KR100189205B1 - Process for the production of crystalline adduct of bisphenol and phenol and apparatus therefor - Google Patents

Abstract

The present invention relates to a method for purifying crystal adducts.

The present invention relates to a method for depositing high quality crystal adducts having a low content of microcrystalline adducts in precipitation of crystal adducts in a crystal column, and a method for separating and recovering high quality crystal adducts from a crystal adduct slurry.

The invention also relates to a crystallizer for depositing high quality crystal adducts.

The present invention also relates to a process for obtaining high quality bisphenol A, which is excellent in color and free from coloration of the melt in evaporating off the phenol contained therefrom from the crystal adduct.

The present invention also provides bisphenol A by a phenol evaporation step of evaporating and removing phenol contained therefrom from a phenol solution containing bisphenol A and steam stripping a phenol-containing bisphenol A obtained from the phenol evaporation step. The present invention relates to a method for efficiently obtaining high quality bisphenol A.

Description

Method for purifying bisphenol A-phenol crystal adduct, method for preparing this crystal adduct, crystallization apparatus for the same, and method for producing bisphenol A

1 shows an example of an apparatus flow diagram when carrying out the first process of the present invention for producing a crystal adduct,

2 shows an example of an apparatus flow diagram when carrying out the second process of the present invention for producing a crystal adduct,

3 shows an example of an apparatus flow diagram when carrying out the third process of the present invention for producing a crystal adduct,

4 shows an example of an apparatus flow diagram when carrying out the fourth process of the present invention for producing a crystal adduct,

5 shows an example of a flow sheet in the case of carrying out the fifth process of the present invention for producing a crystal adduct,

FIG. 6 shows an example of an apparatus flow diagram in the case of steam stripping a phenol solution containing bisphenol A.

7 shows an example of an apparatus schematic for condensing stripping gas,

8 shows another example of an apparatus schematic for condensing stripping gas.

* Explanation of symbols for main parts of the drawings

(In Figure 1)

A, B, C, D: Crystal tower E: Solid-liquid separator

F: Crystal Additive Dissolution Tank P: Inner Cylinder

Q: Microcrystalline Adduct Melting Tank

(In Figure 2)

A, B: crystal tower P: inner cylinder

Q: Microcrystalline Adduct Melting Tank

(In Figure 3)

1: outer cylinder 2: inner cylinder

3: microcrystalline adduct dissolution tank A: crystal tower

(In Figure 4)

A: 1st crystal tower B: 2nd crystal tower

3 to 4: first commercial cooler 5: preliminary cooler

6-7: 2nd phase cooler 8-13: Pump

101-107: crystallization line

(In Figure 5)

A-1, A-2, A-3: Crystallization process B-1, B-2, B-3: Solid-liquid separation process

C-1, C-2: Remelting process

(In Figure 6)

1,2,3 Thin Film Evaporator 4: External Heater

(In Figure 7)

21: first cooler 22: second cooler

(In Figure 8)

21: first cooler 22: second cooler

41: cooler 45: partition plate

The present invention relates to a method for purifying high quality bisphenol A-phenol crystal adducts with good color, a method for producing this crystal adduct, a crystallizer therefor and a method for producing high quality bisphenol A.

It is known to react acetone with excess phenol in the presence of an acid catalyst to produce bisphenol A [2,2-bis (4'-hydroxyphenyl) propane]. In order to separate and recover high-purity bisphenol A from the reaction product, the reaction product is cooled to precipitate a crystalline adduct of bisphenol A and phenol (hereinafter, simply referred to as a crystalline adduct). It is also known to remove it (K-36-23335, K-62-42790).

In such a method for producing bisphenol A, since the purity and color of the bisphenol A recovered as a product largely depends on the purity and color of the crystal adduct, a high purity and good color crystal adduct is obtained. Is required.

In order to obtain a high-purity crystal adduct from a phenol solution containing bisphenol A obtained by reacting acetone with excess phenol, the phenol solution was combined with a plurality of crystallization steps in the middle and a separation step and a dissolution step. The method of processing by a series of crystallization processes is known.

In the conventional method for producing a crystal addition product using a plurality of crystallization processes, one crystal tower is used in the crystallization step of each stage, and a higher purity crystal additive can be obtained by increasing the number of crystallization steps in the crystallization step. have. In this case, however, if the number of crystallization steps is increased, the number of crystal adduct separation devices and crystallization product dissolution tanks also needs to be increased as the number of crystallization steps increases. Include a problem. In addition, by increasing the size of the crystallization tower, it is possible to obtain a high purity crystal adduct. However, if the size of the crystal tower is increased, the size of the cooling device, the crystal adduct circulator and the microcrystalline adduct dissolving tank also needs to be increased exponentially as the size of the crystal tower increases. It also includes the problem of larger size and higher device cost.

As a method for crystallizing a phenol solution containing bisphenol A and depositing a crystal adduct, a part of the crystal adduct slurry is extracted from the crystal tower, cooled by a cooler and recycled to the crystal tower. To maintain the temperature of the crystallization tower at a predetermined crystallization temperature is performed. However, in this method, it is difficult to control the particle size of the crystal adduct in the slurry to be obtained, and the particle size distribution of the obtained crystal adduct varies greatly, and a crystal adduct containing a large amount of fine crystal adduct particles is obtained. On the other hand, since the fine particle-like crystal adduct is large in its surface area, it is easy to adsorb impurities which are coloring causing substances, and the obtained crystal adduct is poor in color. And bisphenol A obtained from such a crystal addition product also contains the substance which is its coloring source, and color steel becomes bad. Therefore, from the viewpoint of obtaining high quality bisphenol A, a method for efficiently producing a crystal adduct slurry having a low content of microcrystalline adduct particles when crystallizing a phenol solution containing bisphenol A to obtain a crystal adduct slurry is obtained. It is important to develop it.

It is known to filter a crystal adduct slurry obtained by crystallizing a phenol solution containing bisphenol A in order to obtain a crystal adduct of high purity, and to wash the separated crystal adduct with high purity phenol. In this case, by increasing the number of crystallization processes, product crystal adducts with increased purity can be obtained. However, in the production of crystal adducts including a plurality of crystallization steps, even when high purity phenol is used in the cleaning liquid for washing the crystal adducts obtained in each crystallization step, impurities having high adsorptivity such as colored substances are used as crystal adducts. Since it is difficult to separate from the crystals, a special high purity of the crystal adduct is not achieved, but there is a problem in that the cost for obtaining a large amount of its high purity phenol is high.

In the method for producing bisphenol A as described above, the purity and color of the bisphenol A recovered as a product greatly depend on the purity and color of the crystal adduct as described above, but the conditions for heating and melting the obtained crystal adduct, It is also greatly influenced by the conditions for evaporating the heated melt.

Separation of phenol from crystalline adducts is generally carried out by evaporation, extraction, stripping with water vapor or the like. As a method for removing phenol from the crystal adduct by evaporation, specifically, as shown in JP-A 52-42790, after melting, the crystal adduct is evaporated at a temperature higher than 180 ° C. and under reduced pressure for 0.1 to 30 minutes. A method of fractionally condensing a phenol to separate it from bisphenol A or a method of vapor stripping a phenol-containing bisphenol after evaporation of a crystal adduct at 180 to 200 ° C. to remove phenol is disclosed (Japanese Patent Application No. 63-132850). . However, the color of bisphenol A obtained by evaporating phenol in the crystal adduct is deteriorated due to the heating in the evaporation treatment. For example, even if it is a crystal adduct having a good color of APHA 15 or less, the color of the product bisphenol A obtained by heating and melting it and evaporating phenol from the melt deteriorates and usually shows an APHA of 40 or more.

In order to solve such a problem, a method of obtaining bisphenol A having an improved color by adding oxalic acid or citric acid to a phenol / water / bisphenol A mixture and then distilling it has been proposed (Public Works No. 40-19333). In addition, in order to improve the stability of bisphenol A, thioglycolic acid, glycolic acid, or polyphosphoric acid is added (Special Publication No. 47-43937), or lactic acid, malic acid, or glycerin acid is added (Japanese Patent Laid-Open No. 2-231444). Etc. are also known. However, also in these methods, the effect of the color improvement of bisphenol A was not enough.

On the other hand, in the method of obtaining a high purity bisphenol A by steam stripping the phenol-containing bisphenol A obtained by evaporating and removing phenol from the crystal adduct, a stripping gas consisting of phenol, bisphenol A and steam is obtained. This stripping gas is attached to the cooling condensation treatment, and bisphenol A and phenol are separated and recovered, but in this case, solids of bisphenol A and phenol are fixed to the base wall of the cooler as a scale, which significantly deteriorates the cooling efficiency of the cooler. There is a problem such as clogging of the cooler.

One object of the present invention is to provide a method for purifying crystal adducts.

Another object of the present invention is to provide a method for efficiently preparing high quality crystal adducts.

It is still another object of the present invention to provide a method for depositing high quality crystal adducts having a low content of microcrystalline adducts in depositing crystal adducts in a crystal column.

It is another object of the present invention to provide a method for separating and recovering a high quality crystal adduct from a crystal adduct slurry.

It is still another object of the present invention to provide a crystallization apparatus for depositing high quality crystal adducts.

It is still another object of the present invention to provide a method for obtaining bisphenol A having a high color and no coloration of a melt in preparing bisphenol A by evaporating and removing phenol contained therein from a crystal adduct.

It is still another object of the present invention to provide a method of preventing the coloring of bisphenol A by heating in the evaporation when producing bisphenol A by evaporating off the phenol contained therefrom from the crystal adduct.

Another object of the present invention is to provide bisphenol A by a phenol evaporation step of evaporating and removing the phenol contained therefrom from a phenol solution containing bisphenol A, and vapor stripping the phenol-containing bisphenol A obtained from the phenol evaporation step. It is to provide a method for efficiently obtaining high quality bisphenol A at the time of manufacture.

It is still another object of the present invention to provide a method for condensing the stripping gas obtained in the stripping treatment of phenol-containing bisphenol A without depositing solid bisphenol A and phenol.

MEANS TO SOLVE THE PROBLEM The present inventors came to complete this invention as a result of earnestly researching in order to achieve the said objective.

According to the present invention, there is provided a method for producing purified phenol, wherein the industrial phenol having a water content of 0.5 wt% or less is brought into contact with a strong acid type ion exchange resin and then distilled at a temperature of 185 ° C or less.

According to the present invention, a phenol solution in which bisphenol A is dissolved in a first crystal tower (A) of two crystal towers connected in series as a first process for preparing a crystal adduct. The crystal additive adducts containing the seed crystals obtained in this crystallization step were introduced into the crystallization column of the crystallization product of bisphenol A-phenol, and introduced into the second crystal tower (B). After the crystal growth of the seed crystal is carried out at a temperature lower than that of the crystallization tower A, the crystal adduct slurry obtained in this first unit crystallization step is introduced into the solid-liquid separation process to separate the crystal adduct from the mother liquor. After re-dissolving the crystal adduct with phenol of higher purity than the mother liquor, it is supplied to the first crystal tower (C) of two crystal towers connected in series for performing the crystallization step of the second stage, and bisphenol A. Crystalline part of phenol At the same time as depositing seed crystals made from the temporary product, the crystal additive adduct obtained in this crystallization step is introduced into the second crystal tower (D), and crystal growth of the seed crystals is carried out at a lower temperature than the first crystal tower (C). A method for producing a bisphenol A-phenol crystal adduct is provided.

According to the present invention, there is provided a method for producing a bisphenol A-phenol crystal adduct using a second (n ≧ 2) crystal tower having an inner cylinder with an opening formed thereon as a second process for producing a crystal adduct. (A) depositing a bisphenol A-phenol crystal adduct in each crystal tower to form a crystal adduct slurry; (b) extracting a crystal adduct slurry from the inner bottom of each crystal tower; (c) After cooling a part of each extracted crystal adduct slurry, it is circulated and introduced into each crystal tower, and (d) the crystal adduct extracted from at least the nth crystal tower among the first to nth crystal towers. A portion of the slurry is heated, the microcrystalline adduct particles contained in the crystal adduct slurry are dissolved, and then circulated into the crystal tower, and (e) the cooled crystal adduct slurry circulated through the crystal column of the first stage. Phenolic containing bisphenol A in The raw material liquid consisting of the liquid is added and supplied to the crystallization tower of the first stage, and (f) a part of the crystalline adduct slurry extracted from the inner cylinder bottom of each crystal tower of the (n-1) th stage from the first stage is transferred. It is added to the circulating cooling line of the crystal addition product slurry in the crystallization tower of each next stage, and it is supplied to the crystallization tower of each next stage, and (g) the crystal addition product slurry extracted from the inner cylinder bottom of the crystallization tower of the nth stage. A method for producing a bisphenol A-phenol crystal adduct is provided, which recovers a part of or a part of the heated circulating slurry in the nth stage as a product crystal adduct slurry.

According to the present invention, a phenol solution containing bisphenol A is supplied into the outer cylinder of the double crystal structure column in which an inner cylinder having an opening is inserted into the outer cylinder of the closed structure as a third process for producing a crystal adduct. The bisphenol A-phenol crystalline adduct slurry was extracted from the bottom of the inner cylinder of the crystal tower, and a part of the extracted crystalline adduct slurry was cooled and circulated and introduced into the outer cylinder to produce swirl flow. After heating a portion of the extracted crystal adduct slurry and dissolving the microcrystalline adduct particles contained in the crystal adduct slurry, the outer cylinder is formed such that swirl flow in the same direction as the cooling crystal adduct slurry is generated from the bottom of the outer cylinder. Part of the crystal adduct slurry extracted from the inner bottom of the cylinder and contained in the crystal adduct slurry at the same time as being circulated in the inside. A portion of the crystal slurry adduct was dissolved in the water particles, there is provided a bisphenol A · phenol determine additional method for producing a water slurry, characterized in that to determine additional product collected as an aqueous slurry.

According to the present invention, as a fourth process for producing a crystal adduct, a crystal tower and a cooler are prepared, a part of the crystal adduct slurry is extracted from the crystal tower, cooled by the cooler, and the cooled crystal adduct slurry is cooled. In the crystallization method in which the precipitated crystal adduct is precipitated in the crystal tower by recycling the crystal column, and the precipitated crystal adduct is extracted from the crystal tower and separated from the crystal adduct slurry. Install one of the condenser coolers as a preliminary cooler, use only a cooler other than the preliminary cooler to cool the crystal adduct slurry, and replace the cooler whose heat transfer efficiency in which the crystal adduct is deposited on the heat transfer surface is reduced. To continuously dissolve and regenerate the crystal adduct attached to the heat transfer surface by heating the cooler whose heat transfer efficiency is lowered. A method for producing a bisphenol A-phenol crystal adduct is provided.

According to the present invention, as a fifth process for producing a crystal adduct, a phenol solution containing bisphenol A is subjected to a crystallization step of n (n ≧ 2) steps, a solid-liquid separation step of n steps, and at least one step of bisphenol A. A crystal addition obtained by solid-liquid separation of the crystallization product obtained in the crystallization process of each stage from the 1st stage to the n-1st stage including the phenol crystal adduct washing | cleaning process and the crystallization adduct reprocessing process of the n-1st stage. After washing with water or as a washing solution, it is redissolved with phenol solution to be supplied to the next step of crystallization, and the crystallization product obtained in the nth step of crystallization is solid-liquid separated, and the obtained crystal adduct is washed with a cleaning liquid to obtain high purity crystals. In the method of obtaining an adduct, (a) refined phenol is used for at least one part of the washing | cleaning liquid of the nth crystal addition product obtained by solid-liquid separation fixation of the nth stage, and (b) At least a part of the phenol solution for re-dissolution of the crystalline adduct obtained in the separation and fixing is used for washing drainage of the crystalline adduct obtained in the solid-liquid separation process of the nth stage or the mother liquor obtained in the solid-liquid separation process of the nth stage, and (c) at least At least a part of the washing liquid of the crystal adduct obtained in the solid-liquid separation process of the n-1 stage is washed with the mother liquor obtained in the solid-liquid separation process of the n-th stage or the liquid drainage of the crystal adduct obtained in the solid-liquid separation process of the n-th stage. And (d) the impurity concentration in the phenol solution for recrystallization of the crystalline adducts and the impurity concentration in the crystalline adduct washing solution in each stage from the first stage to the n-1th stage, Bisphenol A-phenol characterized in that the impurity concentration in the phenol solution for re-dissolution of the crystal adduct is higher than the impurity concentration in the rinse solution of the crystal adduct. A method for preparing a crystal adduct is provided.

According to the present invention, the bisphenol A-phenol crystal adduct slurry obtained by crystallizing a phenol solution containing bisphenol A as a sixth process for producing a crystal adduct is subjected to filtration and has a particle size of 100 µm. A part of the following microcrystalline adduct component is transferred to the filtration side, and the ratio of the microcrystalline adduct component of 100 micrometers or less in particle size collect | recovers the coarse crystal adduct of 20 weight% or less, The bisphenol crystal adduct characterized by the above-mentioned. A manufacturing method is provided.

According to the present invention, as a crystallizer for producing a crystal adduct, a crystal tower and a plurality of coolers are provided, and the crystal tower has a crystal adduct slurry return port at a position other than its bottom, and a crystal adduct slurry outlet at its bottom; Each cooler has an inlet and an outlet, respectively, between the crystal adduct slurry outlet of the crystal tower and the inlet of each cooler, and between the return port of the crystal adduct slurry and the outlet of each cooler, respectively. And the crystal adduct sludge is transferred from the crystal adduct slurry outlet of the crystallite tower to the crystal adduct slurry return port of this crystal tower selectively via a cooler except any one of the coolers of this condenser. The apparatus for obtaining the made bisphenol A phenol crystal adduct is provided.

According to the present invention, as a first process for obtaining bisphenol A, the crystal adduct under substantially neutral conditions of molten color APHA 15 or less composed of bisphenol A and phenol is heated to a condition of oxygen concentration of 0.005 vol% or less in the atmosphere. Provided is a process for producing a high quality bisphenol A characterized by evaporating and removing phenol from the melt obtained while melting.

According to the present invention, as a second process for obtaining bisphenol A, a mixture containing a crystal adduct and aliphatic carboxylic acid having a molten color APHA composed of bisphenol A and phenol under substantially neutral conditions of 15 or less is subjected to a temperature of 130 to Provided is a method for producing a high quality bisphenol characterized in that the phenol is evaporated off at 200 ° C. under reduced pressure.

According to the present invention, a third process for obtaining bisphenol A is composed of bisphenol A and phenol, and the melt color APHA under weakly acidic conditions containing a strongly acidic substance is added to an aliphatic carboxylic acid salt of 15 or less crystal adduct. Provided is a method for producing a high quality bisphenol, wherein the phenol is evaporated off at a temperature of 130 to 200 ° C. under reduced pressure after the addition and mixing of the strong acidic substance in the crystal adduct.

According to the present invention, as a fourth process for obtaining bisphenol A, the molten color APHA supplies a crystal adduct of bisphenol A having a phenol of 15 or less to phenol to an apparatus system including a melting apparatus and an evaporation apparatus, and in this melting apparatus A method of melting a crystal adduct and evaporating a crystal adduct melt in this evaporator to separate bisphenol A and phenol from each other, wherein at least the amount of oxygen adhering to the inner wall surface of the melting apparatus and the evaporation apparatus included in the apparatus system. Is removed to 10 mmol or less per 1 m 2 of the inner wall by organic solvent washing, and then a crystal adduct is supplied to the apparatus, and a method for producing high-quality bisphenol A is provided.

According to the present invention, as a fifth process for obtaining bisphenol A, the molten color APHA has at least one evaporation column in which a molten liquid of crystal adducts of bisphenol A and phenol of 15 or less is disposed inside the member for improving the evaporation surface area. When the phenol is evaporated and removed under reduced pressure, oxygen adhering to the inner wall surface of the evaporation tower and the surface of the member to improve the evaporation traces disposed inside the evaporation tower is 10 millimoles or less per 1 m 2 of surface area. Provided is a method for producing a high quality bisphenol A, characterized in that using the evaporation tower removed in advance.

According to the present invention, as a sixth process for obtaining bisphenol A, when phenol is evaporated off from bisphenol A-phenol crystal adduct to obtain bisphenol A, a phenol solution containing bisphenol A formed from this crystal adduct is thinned. A phenol evaporation step of obtaining a bisphenol A having a phenol content of 1 to 5% by weight by evaporation at a temperature of 160 to 185 ° C. and a pressure of 15 to 60 torr using an evaporator; Bisphenol A containing bisphenol A by carrying out countercurrent contact with stripping gas under the temperature of 170-185 degreeC and the pressure of 15 Troy, and the bisphenol A containing the phenol obtained by this 1st stripping process. And a second stripping process in which the stripping process is carried out by contacting the stripped gas with a fragrance oil at a temperature of 170 to 185 ° C and a pressure of 15 Torr or less. Stripping consisting of steam containing phenol and bisphenol A obtained in the second stripping process, using steam as stripping gas in the second stripping process, and stripping gas in the first stripping process. Provided is a method for producing a high quality bisphenol A characterized by the use of a gas.

According to the present invention, as a seventh process for obtaining bisphenol A, a thin film evaporator is used for a phenol solution containing bisphenol A under substantially neutral conditions and formed of bisphenol A-phenol crystal adducts having a melt color of 15 APHA or less. And a phenol evaporation step of obtaining bisphenol A having a phenol content of 1 to 5% by weight by evaporating under a temperature of 160 to 185 ° C and a pressure of 15 to 60 torr under conditions of an oxygen concentration of 0.005 vol% or less in the atmosphere; In the first stripping process, the bisphenol A containing phenol obtained in the phenol evaporation step is subjected to countercurrent contact with the stripping gas at a temperature of 170 to 185 ° C. and a pressure of 15 Torr or less, and the first stripping process. A second stripping treatment of the bisphenol A containing the obtained phenol by countercurrent contact with the stripping gas at a temperature of 170 to 185 캜 and a pressure of 15 Torr or less; Phenolic and bisphenol A obtained by the process for stripping in a 2nd stripping process using steam as a stripping gas in this 2nd stripping process, and a stripping gas in this 1st stripping process Provided is a method for producing a high quality bisphenol A, which comprises using a stripping gas consisting of steam containing.

According to the present invention, as an eighth process for obtaining bisphenol A, stripping containing a phenol compound, bisphenol A and steam obtained when steam stripping of a mixed melt of phenol and bisphenol under low pressure conditions of 30 Torr or less is performed. A method of condensing a gas, wherein the stripping gas contains phenol or bisphenol A under low pressure conditions up to 30 Torr and under temperature conditions in which the vapor is maintained as a gas and a portion of the phenolic compound is fused into the liquid. Making a countercurrent contact with a first cooling medium made of phenol to condense substantially the entire amount of bisphenol A and a part of the phenol contained in the stripping gas and at the same time obtain a mixed gas of uncondensed steam and phenol; The mixed gas obtained in the first cooling step is condensed under a low pressure condition of 30 Torr or less and substantially the entire amount of the mixed gas. Under the temperature conditions, by contact with an aqueous solution of a phenol consisting of counter-current and the second cooling medium, a second condensation process of the stripping gas consists of a method of cooling step condenses a substantial amount of the mixed gas is provided.

Next, the method for purifying the crystal adduct according to the present invention will be described in detail.

In the purification method of the crystal addition product of this invention, about the crystal addition product of bisphenol A and a phenol, (i) industrial phenol, (ii) reaction process of a phenol and acetone, (iv) the concentration process of a reaction product, (iv) Crystallization Step of Phenol Containing Bisphenol A At least one phenol selected from the phenols obtained in the washing step of the adduct is washed using a purified phenol purified by a specific method. The present inventors earnestly studied the stabilization method of the said phenol itself in order to obtain the phenol suitable for washing | cleaning a crystalline adduct, As a result, after contacting this phenol with a strong acid type ion exchange resin, the phenol purified product obtained by evaporation process is The product bisphenol A obtained by washing the crystal adduct using this purified phenol and removing the phenol from the washed crystal adduct without containing a coloring cause substance which lowers the color of the product bisphenol A has excellent colorability. Found to be low.

The phenol used for washing the crystal adduct in the present invention is a crystallization product of (i) an industrial phenol, (ii) a phenol separated from the reaction product of phenol and acetone, and (iii) a phenol containing bisphenol. Purified product of at least one phenol selected from the used phenols after washing the phenol and (iii) crystal adducts separated from the above is used.

As industrial phenols, those having a phenol purity of 99.5% by weight or more are commercially available, but in the present invention, purified products of these phenols can be used.

The reaction product obtained by the reaction of phenol and acetone is separated from the reaction product in order to concentrate the produced bisphenol A contained therein. However, in the present invention, a purified product of the separated phenol can be used.

When crystallization of a phenol containing bisphenol A is crystallized to precipitate crystal adducts, a plurality of stages of crystallization and solid-liquid separation of crystallization products are usually employed, whereby a plurality of mother liquors (phenols) are obtained. In the invention, a purified product of phenol that forms these mother liquors can be used. The mother liquor purified product used in the present invention may be a purified product of any mother liquor of the mother liquor, but preferably, a mother liquor purified product separated from the crystallization product obtained in the most advanced crystallization step is used.

In the present invention, after washing the crystal adduct, a used phenol is obtained. However, in the present invention, a purified product of the used phenol can be advantageously used.

As a raw material phenol for obtaining the said phenol refined used by this invention, the use of the thing whose purity is 99 weight% or more, Preferably it is 99.5 weight% or more is preferable.

When the phenol is purified, the raw material phenol is first treated by contact with a strong acid type ion exchange resin, but in this case, those having a sulfone group are used as the strong acid type ion exchange resin. Examples of the strong acid type ion exchange resin include sulfonated styrene-divinyl benzene copolymers, sulfonated crosslinked styrene polymers, phenol-formaldehyde-sulfonic acid resins, and benzene-formaldehyde-sulfonic acid resins. All of these resins have a crosslinked structure and are insoluble. The strong acid type ion exchange resin is known to be a gel type or a macroporous type, and in the present invention, use of a gel type, which can be used, is preferable. The macroporous type is different from the gel type, and when used as a catalyst, the activity decreases with time, and therefore its use is not very preferable. In the gel strong acid type ion exchange resin, the degree of crosslinking (% by weight of the crosslinking agent contained in the resin) is 10% or less, preferably 5% or less. Preferred gel type strong acid ion exchange resins used in the present invention include Amberlite and Amberlyst, and Mitsubishi Chemical Corporation, available from Rohm Haas Company, for example. The diamond ion which can make a lips is mentioned. The treatment of phenol using this strong acid type ion exchange resin can be carried out by a method of circulating phenol in a packed column containing a strong acid type ion exchange resin, or by adding a phenol to a stirring tank containing a strong acid type ion exchange resin and stirring the mixture. There is a number. Treatment temperature is 45-150 degreeC, Preferably it is 50-100 degreeC. The contact time of the strong acid type ion exchange resin and phenol is 5 to 200 minutes, preferably about 15 to 60 minutes. When processing phenol using this strong acid type ion exchange resin, the moisture in phenol is 0.5 weight% or less, Preferably it is 0.1 weight% or less. If there is more moisture than this, the impurity charge effect by a strong acid type ion exchange resin worsens. Removal of water up to 0.5% by weight from phenol can be carried out by azeotropic addition of a known azeotropic agent to the phenol.

The phenol contacted with the strong acid type ion exchange resin contains a high boiling point impurity in which impurities are inverted, and the high boiling point impurity is separated as a distillation residue by distillation.

The operating conditions of the distillation column should be able to separate the phenol and high boiling point impurities, but it is necessary to carry out under the condition that the high boiling point impurities are not mixed in the distilled phenol, and it is important to keep the distillation treatment temperature below 185 ° C. . If the temperature is 185 DEG C or lower, the operating pressure is arbitrarily set, but is usually performed under a reduced pressure of 50 Torr to 600 Torr. If the operating temperature exceeds 185 ° C, decomposition of high-boiling impurities, etc. occurs, which is not preferable because it lowers the quality of the purified phenol.

Purified phenol obtained by the above treatment has an APHA standard color of 10 or less and does not particularly deteriorate its color even if adhered to the product bisphenol.

The washing | cleaning of a crystal addition product with refined phenol should just be a method which can fully achieve contact with a crystal addition product and a refined phenol. This washing treatment is, for example, a method in which a mother liquor is removed from the crystal addition product in a solid-liquid separation device such as a filter or a centrifugal separator for separating the crystal addition product, and then purified phenol is introduced into the solid-liquid separation device, Crystal adducts attached to a small amount of mother liquor discharged from the solid-liquid separation device may be washed with purified phenol in a separate stirring bath. The use ratio of the refined phenol to the crystalline adduct is in the ratio of 30 to 1000 parts by weight, preferably 100 to 300 parts by weight with respect to 100 parts by weight of the crystal addition product.

The crystal adduct cleaned by the above-mentioned refined phenol is to attach the purified phenol to the surface thereof, but this itself is sent to the phenol removal process from the crystal adduct, where the phenol is removed and the high purity product bisphenol A is recovered. . The removal of phenol from the crystalline adduct can be carried out by conventionally known methods such as distillation, extraction, steam stripping and the like.

According to the purification method of the crystal addition product of this invention, the product bisphenol A which is excellent in color can be obtained. This invention has the following advantages because it uses the refined product of specific phenol as a washing | cleaning liquid of a crystal addition product.

(1) Since the adduct which does not contain an impurity, especially the impurity which causes coloring, is obtained, the product bisphenol which is high purity and low colorability excellent in color is obtained.

(2) Since no detergent is mixed in the washing liquid, the washing liquid can be circulated and used in the reaction system or crystallization system as it is.

The refined phenol used in the present invention is suitable as a cleaning liquid for the above-described crystalline adducts of phenol and bisphenol A. However, the refined phenol derivatives are excellent in color and therefore have good color, and various raw phenol derivatives such as alkylphenol and phenol resin are manufactured. It is also suitable as.

In addition, by adding a small amount (0.0001 to 0.01 wt%) of oxalic acid or citric acid to the purified phenol obtained in the present invention, it is possible to suppress the deterioration of its color in storage and reaction.

Next, the manufacturing method of the crystal additive of this invention is demonstrated.

[First Process]

1 shows an apparatus flow diagram when carrying out the first process for producing a crystal adduct according to the present invention. In this figure, A, B, C, and D denote a crystal tower, E denotes a solid-liquid separator and F denotes a dissolution tank.

In each crystal tower A, B, C, and D, the inner cylinder P which has an opening part in the upper part is inserted and installed. In addition, microcrystalline adduct dissolution tank Q is provided in each crystal tower A, B, C, and D. The crystal towers A and B are connected in series to form an apparatus system for performing the crystallization process of the first stage, and the crystal towers C and D are connected in series to form an apparatus system for performing the crystallization process of the second stage. do.

A phenol solution containing bisphenol A as a raw material to be treated is supplied to the lower portion of the first crystal tower A in the two crystal towers A and B connected in series through the line 1 and the line 2, wherein the bisphenol A Seeds composed of phenol crystal adducts are precipitated. In this crystal tower A, the phenol solution containing the crystal additive (top) in the upper part of the tower flows out of the inner cylinder P, and is extracted to the outside through the line 3, and the pump 4, the line 5, and the cooler Through 6 and line 2, it is circulated into the first crystal tower A, whereby the phenol solution in the crystal tower A is cooled and the crystal tower A is cooled to a predetermined temperature.

Some of the crystalline adduct slurry (hereinafter simply referred to as slurries), which are crystallization products comprising seed extracted from the inner cylinder P in the crystal tower A, are line 7, pump 8, line 9 and line 10. And a slurry, which is introduced into the microcrystalline adduct dissolution tank Q through the heater 11, in which the fine crystals in the crystal adduct are dissolved and contain only the grains of the coarse crystal of constant size. It is circulated to the bottom, whereby the grain size of the seed crystal contained in the crystal tower A is made uniform, and the crystal seed crystal tower A has a low seed crystal content and a high seed crystal content of the coarse crystal.

The microcrystalline adduct in the crystallization tower A has a large specific surface area and shows high adsorption with respect to a coloring causative substance. Therefore, a seed with good color can be obtained by reducing the particle content of the microcrystalline component in the crystal adduct obtained as seed crystal in the crystal tower A as much as possible. According to the researches of the present inventors, it is found that high purity crystal adducts with good color can be produced by maintaining the particle content of the microcrystalline component having a particle diameter of 100 μm or less in the crystal adduct at 30% by weight or less, preferably 20% by weight or less. It became.

The phenol solution containing bisphenol A used as a raw material treated in the present invention usually contains bisphenol A: 7 to 50% by weight, preferably 10 to 30% by weight, and isomers of bisphenol A, tris phenol and the like as other components. It is included in the proportion of 8% by weight or less.

The temperature of the phenol solution containing bisphenol A supplied by the line (1) is about 1-20 degreeC higher than the saturation temperature of a crystal adduct. The crystallization temperature of the crystallization tower A is 45-70 degreeC, Preferably it is 48-57 degreeC. The slurry circulated through the line 3, the pump 4, the cooler 6, and the line 2 drops in the cooler 6 at about 10 ° C. or less, preferably about 5 ° C. or less. The residence time of the phenol solution in the crystal tower A is 0.5 to 10 hours, preferably 0.5 to 5 hours.

On the other hand, the slurry introduced into the microcrystalline adduct dissolution tank Q through the line 7, the pump 8, the line 10, and the heater 11 is increased in the heater 11 by about 0.5 to 5 ° C. Lose. The residence time of the phenol solution in this tank Q is about 3 to 15 minutes.

In the microcrystalline adduct dissolving tank Q, the microcrystalline adduct having a particle size of 100 μm or less is mainly dissolved, and the slurry in which this microcrystalline adduct is dissolved is returned to the crystallization tower A through the line 13 to be crystallized in the crystallization tower A. Growth is accelerated to obtain a coarse grain finish.

A part of the slurry extracted from the bottom of the inner cylinder P in the first crystal tower A is introduced into the lower portion of the second crystal tower B through the line 7, the pump 8, the line 12 and the line 21, This is where the growth of crystal adducts takes place. This second crystal tower B is operated in the same manner as described with respect to the crystal tower A.

In the crystal tower B, the temperature range is 45-70 degreeC, and is maintained about 3-10 degreeC lower than the crystallization temperature of the crystal tower A. The slurry passing through the cooler 26 is lowered at about 10 ° C or less, preferably about 5 ° C or less.

On the other hand, the temperature of the slurry through the heater 31 is raised about 0.5-5 degreeC here.

In the microcrystalline adduct dissolving tank Q placed in the crystal tower B, a crystal adduct component having a particle size of 100 μm or less is dissolved, and the slurry in which the microcrystalline adduct is dissolved is returned to the crystal tower through the line 33 so that the growth of the crystal is prevented. Is promoted. The concentration of the crystal additives in the slurry extracted from the bottom of the inner cylinder P in the crystal tower B is 35% by weight or less, preferably 25% by weight or less, and the particle content of the microcrystalline component having a particle size of 100 μm or less in the crystal addition product is 30% by weight. It is% or less, Preferably it is 20 weight% or less.

A part of the slurry extracted from the bottom of the inner cylinder P in the second crystal tower B is introduced into the solid-liquid separation device E through the line 35, where the crystal adduct and the mother liquid are separated, and the separated crystal adduct is Through (36), it is introduced into the crystal adduct dissolution tank F, where it is dissolved again.

As the solid-liquid separator E, a conventionally known one, such as a centrifuge or a filtration device, is used. As a dissolution tank F, a conventionally well-known thing, for example, a stirring tank which has a stirrer inside, and a heating type dissolution tank are used.

In the dissolution tank F, it is preferable to introduce purified phenol from the line 81 and to dilute and dissolve the crystal adduct under stirring using this purified phenol. In this case, heating can also be used together as needed. The temperature of a dissolution tank is 70-160 degreeC, Preferably it is 80-100 degreeC. As the purified phenol, one whose purity is higher than that of the mother liquor is used.

In the case of diluting and dissolving the crystal adduct with purified phenol, the purified phenol may have any impurity content which does not cause coloring of the product bisphenol A, but may be any. As the refined phenol which can be preferably used in the present invention, various refined phenols described in the above-described purification method of the crystal adduct can be mentioned.

Such purified phenols have an APHA standard color of 10 or less and do not particularly deteriorate their color even when attached to the crystal adduct and the product bisphenol A.

The phenol solution containing bis phenol A from the dissolution tank F is introduced into the lower portion of the first crystallization tower C which constitutes the crystallization system of the second stage through the line 41. In this case, the concentration of the phenol solution is adjusted so that the concentration of bisphenol A is 7-50% by weight, preferably 10-30% by weight.

This crystal tower C is operated similarly to the crystal tower A shown above. In the crystal tower C, the crystallization temperature is 45-70 degreeC, and it is maintained about 0-10 degreeC higher than the temperature of the crystal tower A. The slurry passed through the cooler 46 is dropped at a temperature of about 10 ° C. or less, preferably about 5 ° C. or less.

On the other hand, the slurry which passes through the heater 51 is raised in temperature about 0.5-5 degreeC here.

In the microcrystalline adduct dissolution tank Q placed in the crystal tower C, the microcrystalline adduct component having a particle size of 100 μm or less is dissolved, and the slurry in which the microcrystalline component is dissolved is returned to the crystal tower C through the line 53 to promote its growth. do.

A portion of the slurry extracted from the bottom of the inner cylinder P in the crystal tower C is introduced into the lower portion of the second crystal tower D, which constitutes the crystallization system of the second stage, through the lines 52, 61, and 62. Here, crystal growth takes place.

This second crystal tower D is operated in the same manner as shown in the crystal tower A.

In the crystal tower D, the crystallization temperature is 45 to 70 ° C., which is about 0 to 10 ° C. lower than the temperature of the crystal tower C, and about 0 to 10 ° C. higher than the crystal tower B.

On the other hand, the slurry which passes through the heater 71 raises the temperature about 0.5-5 degreeC here.

In the microcrystalline adduct dissolving tank Q placed in the crystal tower D, the microcrystalline adduct component having a particle size of 100 μm or less is dissolved, and the slurry in which the microcrystalline component is dissolved is returned to the crystal tower through the line 73 to grow the crystals. Is done. The concentration of the crystal adduct in the slurry extracted from the bottom of the inner cylinder P in the crystal tower D is 35% by weight or less, preferably 25% by weight or less, and the content of the microcrystalline adduct component having a particle size of 100 μm or less in the crystal adduct is 30. Or less, preferably 20% or less by weight.

The slurry extracted from the bottom of the inner cylinder P in the crystal tower D is recovered as a product slurry through the line 80. This slurry is solid-liquid separated as needed, and the obtained crystal adduct is sent to a recovery process of bisphenol A to remove phenol and recover bisphenol A.

According to the first process for obtaining a crystal adduct according to the present invention, a bisphenol A-phenol crystal adduct with high purity and good color of APHA 15 or less can be obtained in high yield.

This bisphenol A phenol crystal adduct removes phenol from this, and gives bisphenol A of high purity and color.

[Second process]

Next, a second process for obtaining a crystal adduct according to the present invention will be described with reference to the drawings.

2 shows an apparatus flow diagram in the case of carrying out the present invention using two (n = 2) crystal towers. In this figure, A represents the crystal tower of the first stage and B represents the crystal tower of the second stage.

In each crystal tower A and B, the inner cylinder P which installed the opening part in the upper part is inserted and installed. In addition, microcrystalline adduct dissolution tank Q is provided in each crystal tower A and B. As shown in FIG.

In each crystal tower A and B which are normally operating, crystal addition product precipitates in the inside, and the slurry of crystal addition product is formed. In addition, from the bottom of the inner cylinder P of the respective crystal towers A and B, the crystalline adduct slurry is discharged to the outside through each of the lines 3 and 23, a part of which is the respective pumps 4, 24 and line ( 5), (25) and coolers (6), (26) and lines (2) and (22) are circulated into the respective crystal towers A and B, whereby the slurry in the crystal towers A and B is cooled to The crystal towers A and B are cooled to a predetermined temperature.

In addition, a part of the slurry including the crystal adducts extracted from the inner cylinder P in each crystal tower A, B is line (7), (27), pump (8), (28), line (9), (29) Is introduced into the microcrystalline adduct dissolution tank Q through lines 10, 29 and heaters 11, 31, whereby microcrystalline particles in the crystal adduct are dissolved and coarse crystal adducts of constant size The containing slurry is circulated through the lines 13 and 33 to the lower portions of the crystallization towers A and B, whereby the particle diameters of the crystal adducts contained in the crystallization towers A and B are evened, and thus the crystallization in the crystallization towers A and B is undetermined. A crystal adduct having a low adduct particle content and a high coarse crystal adduct particle content is produced. The operation of circulating the crystalline adduct slurry in the dissolution tank Q and then circulating to the crystallization tower may be performed at least in the final stage, and may be omitted in the crystallization tower of other stages as necessary.

The microcrystalline adduct in the crystal towers A and B has a large specific surface area and shows high adsorption to the coloring agent. Therefore, by reducing the content of the microcrystalline adduct particles in the crystal adducts obtained in the crystal towers A and B as much as possible, a good color crystal adduct can be obtained. According to the researches of the present inventors, it has been found that high purity crystal adducts having good color can be produced by maintaining the content of microcrystalline adduct particles having a particle diameter of 100 μm or less in the crystal adduct at 30% by weight or less, preferably 20% by weight or less. .

From the bottom of the outer cylinders of the crystal towers A and B when circulating introduction of the temperature lowered slurry through the lines (2) and (22) and the temperature-rise slurry through the lines (13) and (33) into the crystal towers A and B The swirling flow of the same direction is made into the outer cylinder. In this case, Preferably it introduces so that it may become tangential with respect to an outer cylinder inner peripheral surface, and it is performed so that the introduction position may differ. In addition, the introduction position of these two slurries is represented by the angle from the center point of an outer cylinder, Preferably it is good to carry out in the position which is 90-180 degree away. In addition, the introduction positions of the two slurries need not necessarily be on the same horizontal line so as to cause the swirl flow in the same direction, and there may be some height difference at least under the outer cylinder.

As described above, the respective slurries passing through the lines 2, 22 and 13, 33 are introduced into the crystal towers A and B such that the introduction direction thereof is tangential to the inner circumferential surfaces of the crystal towers A and B. While the swirl flow is generated in the slurry in the crystallization towers A and B, the swirl flow rises to the upper end of the inner cylinder P, and then descends from the opening of the upper portion of the inner cylinder P to the lower portion of the inner cylinder P. Emitted from.

By producing such swirling flows in the crystal towers A and B, the following effects can be obtained.

(1) Two liquid streams of different temperatures can be effectively and uniformly mixed.

(2) Since dispersion of the slurry is prevented and the slurry concentration in the outer cylinder is uniform, nonuniformity of residence time in the outer cylinder of the crystal addition product particles can be eliminated.

(3) A sufficient linear velocity can be obtained to prevent sedimentation deposition in the outer cylinder of the crystal adduct particle.

In this invention, the raw material liquid which consists of a phenol solution containing bisphenol A is added to the cooled slurry through the cooler 6 circulated to the crystal tower A of the 1st stage, and is supplied to the crystal tower A of the 1st stage.

In the present invention, a part of the slurry extracted from the bottom of the inner cylinder P of the crystallization tower A of the first stage is added to the slurry cooled through the cooler 26 circulated to the crystallization tower B of the second stage and the second It is supplied to the crystal tower B of the stage. By supplying the slurry obtained from the crystallization tower A of the first stage to the crystallization tower B of the second stage in this way, efficient cooling of the feed slurry is achieved, and the heat of cooling is used for the growth of the crystal adduct particles so that the degree of supersaturation of the liquid is achieved. Advantages are reduced and the particle size distribution of the crystal adduct particles can be increased.

The temperature of the phenol solution containing bisphenol A supplied from the line (1) is about 1-20 ° C higher than the saturation temperature of the adduct and the temperature of the crystallization tower A is 45-70 ° C. The slurry circulated through the line 3, the pump 4, the cooler 6 and the line 2 is lowered in the cooler 6 at a temperature of about 10 ° C or less, preferably about 5 ° C or less. The residence time of the phenol solution in the crystal tower A is 0.5 to 10 hours, preferably 0.5 to 5 hours.

On the other hand, the slurry introduced into the microcrystalline adduct dissolution tank Q through the line 7, the pump 8, the line 10, and the heater 11 rises in the heater 11 by about 0.5 to 5 ° C. And remain in the microcrystalline adduct melting tank Q. The residence time of the slurry in this tank Q is about 3 to 15 minutes.

In the microcrystalline dissolution tank Q, crystal adducts having a particle diameter of 100 µm or less are dissolved, and the slurry in which the microcrystalline is dissolved is returned to the crystal tower A through the line 13 to promote crystal growth.

A part of the slurry extracted from the bottom of the inner cylinder P in the crystal column A of the first stage is passed through the line 7, the pump 8, the line 12, and the line 21, and then passes through the cooler 26. It is added to the slurry circulated to the stone tower B and introduced into the crystallization tower B of the 2nd stage. The crystal tower B of the second stage is operated in the same manner as described with respect to the crystal tower A.

The temperature of the crystal tower B is maintained at a temperature 3 to 10 ° C. lower than the temperature of the crystal tower A. On the other hand, the slurry which passes through the heater 31 raises the temperature here about 0.5-5 degreeC, and the temperature of the microcrystal addition product dissolution tank Q which was attached to the crystallization tower B by this is 0.5-5 degreeC than the temperature of the crystallization tower B. It is maintained at a high temperature.

In the microcrystalline adduct dissolution tank Q placed in the crystal tower B, crystal adducts having a particle diameter of 100 μm or less are dissolved, and the slurry in which the microcrystals are dissolved is returned to the crystal tower B through the line 33 to grow crystals of the crystal adduct. This is facilitated. The concentration of the crystal adduct in the slurry extracted from the bottom of the inner cylinder P in the crystal tower B is 35% by weight or less, preferably 25% by weight or less, and the content of microcrystalline adduct particles having a particle diameter of 100 μm or less in the crystal adduct is 30% by weight. It is% or less, Preferably it is 20 weight% or less.

A part of the slurry extracted from the bottom of the inner cylinder P in the second crystal tower B is recovered as a product slurry through the line 35. This slurry is solid-liquid separated as needed, and the obtained crystal adduct is sent to the recovery process of bisphenol A, a phenol is removed, and bisphenol A is collect | recovered.

The product slurry can be extracted from the bottom of the inner casing P of the second stage as described above, and the part of the heated circulating slurry circulated from the microcrystalline adduct dissolution tank Q through the line 33 to the crystal tower B is produced. It can also collect | recover as a slurry.

In FIG. 2, although the apparatus flow diagram in the case of implementing the method of this invention using two crystal towers A and B is shown, it can carry out similarly even if more crystal towers are used. That is, when performing crystallization using n (n≥2) crystallization towers, the raw material solution is added to the cooled crystal additive slurry circulated to the crystallization tower of the first stage, and is supplied to the crystallization tower of the first stage, A portion of the crystal adduct slurry extracted from the inner cylinder bottom of each crystal tower from the first stage to the (n-1) stage is added to the circulating cooling slurry in the crystal tower of the next stage and After supplying to the stone tower, part of the crystalline adduct slurry extracted from the inner cylinder bottom of the nth stage (final stage) crystal tower or a part of the heated circulation slurry in the nth stage crystal tower is recovered as a product slurry. do. In this case, the temperature of the crystallization tower is maintained at the highest temperature of the crystallization tower of the first stage and the temperature of the crystallization tower of the nth stage is the lowest, but is sequentially lowered from the first stage to the nth stage. do. The temperature difference between each crystal tower and the crystal column of each next stage is 3-10 degreeC, Preferably it is 5-8 degreeC, and the temperature of the crystal tower of each next stage is kept as low as this temperature difference.

According to the second process of the present invention, bisphenol A-phenol crystal adducts having high purity and good color can be obtained in high yield.

This bisphenol A phenol crystal adduct removes phenol from this and gives bisphenol A which is high purity and color is good.

[Third Process]

Next, a third process for obtaining a crystal adduct according to the present invention will be described with reference to the drawings.

3 is an apparatus flow diagram for carrying out the third process of the invention. In this figure, (1) is an outer cylinder, (2) is an inner cylinder, (3) is a microcrystalline adduct dissolution tank, (4) is a cooler, (5) is a heater, (6), (7) is a pump, and A is It is a crystal tower.

The crystal tower A has a double cylinder structure in which an inner cylinder 2 having an opening part is inserted into an outer cylinder 1 of a sealed structure.

The closed structure as used in the present invention refers to a state in which the crystal tower is sealed with an inert gas, rather than being in an open air state.

Opening the atmosphere will absorb some of the oxygen in the atmosphere in the slurry in the crystallization column, worsening the color of the adduct, and adversely affecting the subsequent treatment, so that high-quality adduct, even bisphenol A, cannot be obtained. . Therefore, in the crystal tower, it is necessary to seal with an inert gas in order to prevent the mixing of oxygen. In this case, if oxygen can be prevented from mixing, it is not necessarily a sealed pressure vessel that can withstand high pressure. In addition, the crystal tower does not need to provide a direct extraction hole in the outer cylinder portion, but installs the inner cylinder on the central axis of the swirl flow of the slurry inside and raises the swirl flow of the slurry to the upper portion thereof, so that the slurry flows from the opening of the upper portion of the inner cylinder to the inside of the inner cylinder. After descending, take the way out from the bottom of inner tube. This ensures uniform mixing and sufficient residence time against adduct particles for the circulating slurry introduced.

In order to carry out the present invention preferably, first, a phenol solution containing bisphenol A, which is a raw material to be treated, is filled into the crystallization tower A through lines 8 and 9 and at the same time from the bottom of the inner cylinder 2 Extract the phenol solution through (10), and through the line (11), the pump (6), the line (12), the cooler (4), the line (13) and the line (9) into the outer cylinder at the bottom of the crystallization tower A. Cycle continuously. By this operation, the phenol solution in the crystal tower A is cooled to crystallize the crystal adduct and produce a slurry containing the crystal adduct. The slurry is extracted from the bottom of the inner cylinder 2, cooled in the cooler 4 as described above, and then circulated into the outer cylinder 1 of the lower portion of the crystal tower A.

In addition, a portion of the slurry from the bottom of the inner cylinder 2 is transferred to the line 10, line 14, pump 7, line 15, heater 5, tank 3 and line 16, (17). Through) continuously into the outer cylinder (1) of the bottom of the crystal tower A. By this operation, the microcrystalline adduct particles in the slurry extracted from the bottom of the inner cylinder 2 are dissolved in the tank 3, and the slurry having a low content of the microcrystalline adduct particles is circulated into the crystal tower A. As a result, the content rate of the microcrystalline adduct particle in the crystallization tower A is reduced.

In this state, the raw material phenol solution is introduced into the outer cylinder 1 at the bottom of the crystal tower A through the line 8 and the line 9, and at the same time, the product slurry is removed from the bottom of the inner cylinder 2. Eject through 20).

In this case, if the slurry can be flowed down by gravity in the next process, it is extracted using the line 20 in this way. Otherwise, a part thereof may be extracted from the discharge line 21 of the pump 7. It may be. In addition, a part of the slurry having a small content of microcrystals may be recovered from the line 18, and this may be used as a product crystal adduct slurry.

In the present invention, when introducing the temperature-reduced slurry through the line (9) and the temperature-rise slurry through the lines (16), (17) into the outer cylinder (1), the swirl flow in the same direction from the lower portion of the outer cylinder into the outer cylinder Introduced to occur. In this case, Preferably it introduces so that it may become tangential with respect to an outer cylinder inner peripheral surface, and it introduces so that the introduction position may differ. If the introduction position is too close, the local flow may be disturbed, and a flat swirl flow may not be obtained, and the structure and strength of the crystal tower may not be expected. Therefore, the introduction positions of these two slurries are preferably displayed at an angle from the center point of the outer cylinder and preferably at a position 90 to 180 degrees apart. And if it is for producing the swirl flow in the same direction, the introduction positions of the two slurries need not necessarily be on the same horizontal plane, and there may be some height difference at least in the lower part of the outer cylinder.

As described above, each slurry flowing through the lines 9, 16, and 17 is introduced into the outer cylinder so that the swirl flow is generated in the same direction, and the swirl flow flows into the inner cylinder 1 (2). ) Up to the upper end and then descend from the upper opening of the inner cylinder 2 into the inner cylinder 2 and exit from the bottom of the inner cylinder through the line 10.

By producing such a swirl flow in the outer cylinder 1, the following effects can be acquired.

(1) Two liquid streams of different temperatures can be effectively and uniformly mixed.

(2) Since dispersion of the slurry is prevented and the slurry concentration in the outer cylinder is uniform, nonuniformity of residence time in the outer cylinder of the crystal addition product particles can be eliminated.

(3) A sufficient linear velocity can be obtained to prevent sedimentation deposition in the outer cylinder of the crystal adduct particle.

In addition, a portion of the slurry extracted from the bottom of the inner cylinder (2) as described above is line 10, line 14, pump (7), heater (5), tank (3) and line (16), (17). When circulating through the crystallization tower A through the microcrystalline adduct in the slurry dissolves and disappears in the tank 3, a slurry containing a coarse crystallization adduct having a predetermined size is circulated to the crystallization tower A through the lines 16 and 17. As a result, the grain size of the crystal adduct contained in the crystal tower A becomes even, thereby producing a crystal adduct in the crystal tower A having a low content of microcrystalline adduct particles and a high content of coarse crystal adduct particles. This microcrystalline adduct in crystal tower A has a high specific surface area, and thus exhibits high adsorption to the coloring agent. Therefore, by reducing the content of microcrystalline adduct particles in the crystal adduct obtained in the crystal tower A as much as possible, a crystal adduct with good color can be obtained. According to the researches of the present inventors, it is found that a high purity crystal adduct having good color can be produced by maintaining the content of microcrystalline adduct particles having a particle diameter of 100 μm or less in the crystal adduct at 30% by weight or less, preferably 20% by weight or less. It became.

The temperature of the phenol solution containing bisphenol A supplied from the line 8 is about 1-20 degreeC higher than the saturation temperature of an adduct, and the crystallization tower A is 45-70 degreeC. The slurry circulated through the line 11, the pump 6, the cooler 4, and the line 9 drops in the cooler 4 at a temperature of about 10 ° C. or less, preferably about 5 ° C. or less. The residence time of the phenol solution in the crystal tower A is 0.5 to 10 hours, preferably 0.5 to 5 hours.

On the other hand, the slurry introduced into the microcrystalline adduct dissolution tank 3 through the line 14, the pump 7, the line 15, and the heater 5 has a temperature of 0.5 to 5 ° C. in the heater 5. It is raised to an extent and held in the microcrystalline dissolution tank 3. The residence time of the phenol solution in this tank 3 is about 3 to 15 minutes.

In the microcrystalline dissolution tank 3, a crystal adduct having a particle size of 100 μm or less is dissolved, and the content of the crystal adduct particle having a particle diameter of 100 μm or less in the crystal adduct in the slurry passing through the line 16 is 30% by weight or less, preferably 20 It is weight% or less.

Some of the slurry exiting from the bottom of the inner column 2 is recovered as product slurry via line 20. In this case, in the case of causing the slurry to flow down by gravity in the following process, it is extracted using the line 2 in this way. Otherwise, a part thereof may be extracted from the discharge line 21 of the pump 7. have. In addition, a part of the slurry having a small content of microcrystals may be recovered from the line 18, and this may be used as a product crystal adduct slurry. This slurry can be subjected to crystallization in the same manner as above. In addition, the crystal addition product can be obtained by solid-liquid separation treatment of this slurry.

According to the third process of the present invention, it is possible to efficiently produce crystal adducts having a low content of microcrystalline adduct particles and good color. This crystal adduct gives a good color bisphenol A by separating and removing phenol from it.

[Fourth process]

Next, a fourth process for obtaining a crystal adduct according to the present invention and a crystallizing apparatus for carrying it out will be described with reference to FIG.

In FIG. 4, A is the first crystal tower, B is the second crystal tower, (3) to (4) the first commercial cooler, (5) is the preliminary cooler, and (6) to (7) Represents a second commercial cooler.

The phenol solution of bisphenol A as a raw material is first introduced into the first crystal tower A from the line 101. A portion of the crystal adduct slurry drawn by line 102 from the bottom of first crystal tower A is passed through pump 8 and line 104 to second crystal tower B, and a portion of After cooling through the pumps 9 and 10 and the coolers 3 and 4, it is returned from the line 103 to the first crystal tower A. The temperature in the first crystal tower A is determined according to the temperature and the inflow ratio of the raw material liquid flowing in from the line 101 and the circulating liquid flowing from the line 103, and when the concentration reaches the corresponding temperature Precipitation of the crystal adduct which is equimolar between bisphenol A and phenol occurs. The liquid flowing in the circulation line from line 102 through pumps 9 and 10 and coolers 3 and 4 to line 103 is thus a slurry comprising the crystal adduct. Similarly, a portion of the liquid drawn by line 105 from the bottom of second crystal tower B is sent by line 107 to a filtration device for recovering the crystal adduct, so that some of the pumps 12 and 13 ) And cooler (6) and (7) and then back to the second crystal tower B from line (106). The temperature in the second crystal tower B is determined according to the respective temperatures and inflow ratios of the liquid flowing from the line 104 and the liquid flowing from the line 106, and the bisphenol until the concentration corresponding to the temperature is reached. Precipitation of the crystal addition product which is equimolar with A of phenol occurs. The liquid flowing in the circulation line from line 105 through pumps 12 and 13 and coolers 6 and 7 to line 106 is therefore a slurry comprising the crystal adduct.

The line comprising the pump 11 and the cooler 5 is a spare line to take over the load when another pump and cooler is removed from the line. An example of the operation of the commercial coolers 3, 4, 6 and 7, and the preliminary cooler 5 is shown in Table 1 below.

In Table 1, A represents cooling the slurry of the first crystallization system, and B represents cooling the slurry of the second crystallization system. The operation mode is shifted from (1) to (5) in sequence, and one cycle is completed at the time when it returns to (1) again. In order to dissolve the crystal adducts deposited on the heat transfer surface, it takes about 1 hour after the liquid temperature in the cooler rises above the crystal dissolution temperature, but the heat transfer effect of the cooler decreases due to the adhesion of the crystal adducts. The time until regeneration is required also depends on the conditions of use, but at least several ten hours and the cycle is easily attainable. In the fourth process of the present invention and the crystallization device for the implementation thereof, in the operation of the externally cooled crystallization device system which cools the crystal adduct slurry using the cooler as described above, the coolers are provided in parallel with the plurality of coolers, One of the coolers of the cooler is used as a pre-cooler, and the crystal adduct slurry is cooled using only a cooler other than the pre-cooler. At the same time, it is characterized by dissolving and regenerating the crystal adduct attached to the heat transfer surface by heating the cooler whose heat transfer efficiency is lowered. In this case, one of the plurality of coolers may be fixedly operated as a preliminary cooler at all times, or may be operated cyclically with each cooler sequentially as a preliminary cooler.

The crystal tower in the present invention may be one, but preferably, as shown in FIG. 4, the crystal tower is installed in two towers in series to perform two-stage crystallization, and a commercial cooler is separately installed for each crystal tower. It is good to install one common cooler in both crystal towers. If the two-stage crystallization is carried out by installing two crystal towers in series, the difference between the inlet temperature of the crystalline adduct slurry and the temperature in the tower in each tower can be reduced, so that sudden crystal precipitation can be avoided. Large crystal adducts can be obtained. In addition, since the load on the cooler can be reduced, precipitation of crystals on the cooler heat transfer surface can be suppressed. And if the preliminary cooler is common to both towers, the installation cost can be reduced. In this case, the preliminary cooler alternately cools two kinds of liquids having different temperatures and solute concentrations, but it was found that a slight difference in temperature or solute concentration is not a problem if the heat exchange capacity is the same.

In the external cooling crystallizer system which cools the crystal addition product slurry using a cooler, the liquid flowing through the cooler is usually a slurry containing crystal (crystal addition product of bisphenol A and phenol). The cooler is a kind of indirect heat exchanger, and the slurry passing through the cooler is cooled through the heat transfer surface. Thereby, precipitation of a crystal advances to the extent corresponded to the temperature fall. However, there is a time lag between the temperature drop and crystal precipitation, and crystals gradually precipitate after being temporarily supersaturated. In addition, precipitation of crystal adducts requires the presence of seed crystals, and the precipitation proceeds in the form of crystals already existing in the slurry rather than new crystals because the crystals in the slurry act as seed seeds. Therefore, the rate at which the scale (composed of fine crystals and impurities) is formed on the heat transfer surface of the cooler is not very large at first, but once attached, it accelerates gradually. When this scale accumulates, a problem arises that the heat transfer efficiency (ie, cooling efficiency) decreases first, and when the scale is peeled off and transported to the crystal tower, there is a problem that the purity of the product decreases. Therefore, normally, when the scale accumulates, the cooler is removed from the line and cleaned. Since the operation of crystallization must be stopped during this operation, the operation of crystallization to some extent cannot be done frequently, and as a result, the cooler is used until a considerable scale has accumulated.

According to the invention the above problem is completely solved. That is, in the present invention, when fine crystals slightly precipitate on the cooler heat transfer surface without cleaning and removing the scale, the load of the cooler is switched to a preliminary cooler, and the cooler is allowed to flow a heating medium instead of a cooling medium as necessary. This is to dissolve and remove the fine crystals deposited on the heat transfer surface. The heating medium may be separately provided with a circulation line, and the cooler may be connected to the heating medium circulation line. In this way, since fine crystals are removed before they form a hard scale, the scale load problem can be avoided by simply removing the cooler from the line and heating it, without time-consuming and laborious scale cleaning. will be.

[The fifth process]

Next, a fifth process for obtaining a crystal adduct according to the present invention will be described with reference to the drawings.

5 shows an example of a flow sheet in the case of carrying out the method of the present invention. In FIG. 5, A-1, A-2, and A-3 represent a 1st crystal process, a 2nd crystal process, and a 3rd crystal process, respectively. B-1, B-2, and B-3 represent a 1st solid-liquid separation process, a 2nd solid-liquid separation process, and a 3rd solid-liquid separation process, respectively. C-1 and C-2 represent the 1st remelting process and the 2nd remelting process of a crystal addition product, respectively.

In the case of producing the crystal adduct according to the flow sheet shown in Fig. 5, in the steady state flowchart, a phenol solution containing bisphenol A, which is a raw material for crystallization, is subjected to the first crystallization step A- through line (1). The crystallization product obtained in the first crystallization step A-1 is introduced into the first solid-liquid separation step B-1 via line 2, where the first crystal adduct D-1 and the first mother liquor F-1 are introduced. The first mother liquor F-1 contains useful components such as phenol and bisphenol A, and is circulated in the reaction process between phenol and acetone after proper treatment. The first crystal adduct separated from the first crystallized raw anum was washed with the second mother liquor F-2 obtained in the second solid-liquid separation process of the next stage, B-2, and the first wash liquid E-1 obtained in this washing was It is circulated by the reaction process between phenol and acetone.

The first crystal adduct D-1 washed with the second mother liquor F-2 as described above is introduced into the first remelting process C-1 to add the second crystal from the second solid-liquid separation process B-2 in the next stage. It is dissolved by the water washing drainage E-2 and then introduced into the second crystallization process A-2 via the line 3.

The crystallization product obtained in the second crystallization step A-2 is introduced into the second solid-liquid separation step B-2 via line 4, where it is separated into the second crystal adduct D-2 and the second mother liquor F-2. The second mother liquor F-2 is used to wash the crystal adduct D-1 separated in the first solid-liquid separation step B-1 as described above. On the other hand, the second crystal adduct D-2 is washed with the third mother liquor F-3 obtained in the third solid-liquid separation step B-3 of the next stage, and the second wash liquid E-2 is the first material dissolution step as described above. It is used as a phenol solution for melt | dissolution of the 1st crystal addition product D-1 in C-1.

The second crystal adduct D-2 washed with the third mother liquor F-3 as described above is introduced into the second remelting process C-2 to add the third crystal from the third solid-liquid separation process B-3 in the next stage. After dissolving by the water washing liquid E-3, it is introduced into the third crystal process A-3 through the line 5.

The crystallization product obtained in the third crystallization step A-3 is introduced into the third solid-liquid separation step B-3 via line 6, where it is separated into the third crystal adduct D-3 and the third mother liquor F-3. The first mother liquor F-1 is used to clean the second crystal adduct D-2 separated in the second solid-liquid separation step B-2 as described above.

The third crystal adduct D-3 is washed with purified phenol F, and the third wash basin E-3 is dissolved in the second crystal adduct D-2 in the second remelting step C-2 as described above. Used as a phenolic solution.

The third crystal adduct D-3 washed with purified phenol F obtained in the third solid-liquid separation process is recovered as a product.

In the present invention, as the purified phenol F, usually, any one can be used as long as the molten color APHA is preferably 15 or less.

As the purified phenol that can be preferably used in the present invention, for example, various phenol purified products presented with respect to the purification method of the above crystal addition product can be used.

As the cleaning liquid of the crystal adduct of each step in the present invention, a mother liquid from the next stage is used for at least a portion thereof, but in this case, it is also possible to use a part of the cleaning liquid from the next stage as necessary. In addition, as a phenol solution for dissolving the crystalline adduct in the re-dissolution process of each stage, a washing drainage from the next stage is used for at least a portion thereof, but in this case, a part of the mother liquor from the next stage is used in combination. You can do it. In the present invention, both the washing liquid used for washing the crystal adduct and the phenol solution for dissolving the crystal adduct have an impurity concentration contained in the downstream side, that is, from the first stage crystallization process to the n stage crystallization process. It's getting less as you head. In other words, the impurity concentration in the crystalline addition product washing liquid and the phenol solution for dissolving the crystalline adduct used in each step is larger than that in the next step. The impurity concentration in the washing liquid used in each adjacent stage decreases almost equipotentially.

In addition, an impurity as used in this specification means the side product at the time of producing bisphenol A by reaction of a phenol and acetone. Such impurities include isomers of Bisphenol A, Chromman compounds and the like.

In addition, in the present invention, a part of each washing process from the first stage to the n-th stage is omitted according to the required purity of the product additive, and the crystal additives obtained in the solid-liquid separation process are directly brought to the next stage of remelting process. It may be. In this case, the phenol solution used in the re-dissolution process uses the mother liquor (or washing liquid) obtained in the solid-liquid separation step of the next step.

As described above, in the present invention, the amount of the phenol used as a whole can be lowered and the cost can be reduced by adjusting the amount of the phenol solution for washing used in each stage according to the required purity of the product adduct.

Although the crystallization process in this invention is two or more stages, and the example which includes the three-stage crystallization process was shown in the figure, even if it is four or more stages of crystallization processes, it can carry out as mentioned above.

According to the fifth process of the present invention, high-quality crystal adducts can be obtained only by using purified phenol only for washing the crystal adducts of the final stage. Therefore, in this invention, the use amount of high-purity refined phenol is at least, and there exists an advantage that the manufacturing cost of a crystal addition product may be low.

[The sixth process]

A sixth process for obtaining crystal adducts according to the present invention is described below. The crystal adduct slurry used as a raw material of this process is a crystal adduct slurry obtained by crystallizing the reaction product obtained by reacting phenol and acetone, or a crystal obtained by remelting and crystallizing the crystal adduct separated from the slurry. It may be an adduct slurry or the like.

In the present invention, when this crystalline adduct slurry is filtered to separate the crystalline adduct from the mother liquor, at least a part of the microcrystalline adduct component having a particle diameter of 100 μm or less among the crystalline adducts contained in the slurry is transferred to the filtrate (mother liquor) side. To obtain a coarse crystal adduct having a proportion of the microcrystalline adduct component having a particle size of 100 µm or less of 20% by weight or less, preferably 15% by weight or less. In this case, in order to transfer the microcrystalline adduct component to the filtrate side, it can be performed according to the selection of a filter or selection of filtration operation conditions. Generally as a filter, the mesh is 100-150 micrometers, Preferably it is 100-125 micrometers. When the microcrystalline adduct component according to the filtration operation conditions is shifted to the filtrate side, it can be performed depending on the thickness of the crystal adduct cake obtained by the filtration treatment and the frequency of backwashing the cake.

In the present invention, the coarse crystal adduct obtained as described above is itself a high quality having a low impurity content, but the quality can be further improved by washing the coarse crystal adduct with purified phenol again. In this case, as the purified phenol, various phenol purified products presented with respect to the purification method of the above crystal adduct can be used.

The washing | cleaning of a crystal addition product with refined phenol should just be a method which can fully achieve contact of a crystal addition product with refined phenol. This washing treatment is a method of removing the mother liquor from the crystal adduct in a solid-liquid separation device such as a filter or centrifugal separator for separating the crystal adduct, and then introducing the purified phenol into the solid-liquid separation device to wash the liquid or separating the solid-liquid. The crystal adduct adhered to a small amount of mother liquor discharged from the apparatus may be washed with purified phenol in a separate stirring tank. The use ratio of the purified phenol relative to the crystal adduct is 50 parts by weight or more, preferably 100 parts by weight or more based on 100 parts by weight of the crystal addition product.

The crystal adduct washed by the above-mentioned purified phenol is to attach the purified phenol to the surface thereof, which is sent from the crystal adduct to the phenol removal process to remove the phenol from which the high-purity product bisphenol A is recovered. The removal of phenol from the crystalline adduct can be carried out by conventionally known methods such as distillation, extraction, steam stripping, and the like.

According to the present invention, it is possible to easily obtain a crystal adduct having excellent color stability and good thermal stability that is hardly colored. In addition, bisphenol A obtained by removing phenol from this crystalline adduct is also a high quality product which is excellent in color and hardly colored.

Next, each process for obtaining bisphenol A according to this invention is explained in full detail.

[First Process]

The first process for obtaining bisphenol A according to the invention is described below.

In the present invention, the crystal adduct is used under substantially neutral conditions and has a melt color APHA of 15 or less, preferably 15 or less.

In the reaction between phenol and acetone for obtaining bisphenol A, strong acidic substances such as hydrochloric acid, sulfuric acid, and sulfonic acid type strong ion exchange resins are used as the acid catalyst. Such strong acidic substances not only act as catalysts in the reaction system between phenol and acetone, but also exhibit the action of promoting the generation of colored substances and impurities under heating conditions, thereby reducing the color and purity of the recovered bisphenol A and phenol. Therefore, it is proposed to remove or neutralize such strong acidic substances after the reaction so as not to flow to a subsequent dephenol process involving heating conditions. For example, in a reaction using hydrochloric acid as a catalyst, a method is proposed in which a product is heated to remove hydrochloric acid, and the remaining hydrochloric acid is neutralized with alkali to neutralize to pH 5 to 6 (Japanese Patent Application No. 47-43937). In addition, in the method using a strong acid type ion exchange resin, organic sulfonic acid is detached and mixed into the product by decomposition of the ion exchange resin when reacting, and thus a method of neutralizing the organic sulfonic acid using a weakly basic ion exchange resin is proposed. (US Pat. No. 4191843). On the other hand, since the color and purity of phenol and bisphenol A are lowered not only by acid but also by alkali, it is necessary to neutralize strong acidic substances by alkali so as not to exceed the neutralization point.

As described above, in the reaction in which phenol and acetone are reacted in the presence of a strong acidic substance, it is necessary to neutralize the strong acidic substance present in the reaction product so as not to cross the neutralization point or to remove it from the reaction system. When the alkali used for neutralization remains, it is necessary to remove this alkali. In addition, the removal of the strongly acidic substance or alkali present in the reaction product can be removed by using a multi-stage crystallization process in the subsequent crystallization process.

The term crystalline adduct under substantially neutral conditions used in the present invention means a crystalline adduct with the influence of the above strong acidic or alkaline substances removed. Such a crystal adduct is dissolved in an aqueous methanol solution adjusted to acidity so as to show pH 5.0, and in a pH measurement method under substantially non-isolated conditions of phenol, pH 4.90-5.50, preferably pH 4.95-5.20. Say that. In addition, pH of the crystal addition product shown in this specification is obtained from the said measuring method.

In the present invention, as the crystal adducts, those having substantially neutral conditions as described above are used, but in this case, it is preferable to keep the molten color APHA of the crystal adducts of 15 or less. Melt color APHA of 15 or less can be obtained by maintaining the crystal adduct under substantially neutral conditions as described above, but can be obtained by increasing the number of crystallization stages in the crystallization step as necessary, It can be obtained by washing water with purified phenol.

When the crystalline adduct is washed with the purified phenol, the purified phenol may be any one as long as the content of impurities is small so as not to cause coloring of the product bisphenol A. In the present invention, as the purified phenol, usually, the melt color APHA is 10 or less, preferably 5 or less.

As the refined phenol which can be preferably used in the present invention, various purified phenols, for example, can be cited as the purification method of the above crystal addition product.

The washing | cleaning of a crystal addition product with refined phenol should just be a method which can fully achieve contact of a crystal addition product with refined phenol. This washing treatment is a method of removing the mother liquor from the crystal adduct in a solid-liquid separation device such as a filter or a centrifugal separator for separating the crystal adduct, and then introducing purified phenol into the solid-liquid separation device to wash the liquid. The crystal adduct which a small amount of mother liquid discharged | emitted from an apparatus adheres to can also be wash | cleaned with refined phenol in a separate stirring tank. The use ratio of the purified phenol relative to the crystal adduct is 30 to 1000 parts by weight, preferably 100 to 300 parts by weight with respect to 100 parts by weight of the crystal adduct.

The purified phenol after being used for washing the crystal adduct is used as it is or as a raw material phenol in the synthesis reaction step of the bisphenol A after being used for washing the prepared crystal adduct obtained in the previous crystallization step.

In the present invention, the phenol is evaporated and removed from the melt obtained by heating and melting the crystal adduct. At this time, the oxygen concentration in the heating atmosphere in the heating melting step and the step of evaporating and removing the phenol from the melt are 0.005 vol% or less. Preferably it is kept at 0.001 vol% or less.

The temperature at the time of heating and melting a crystal adduct is 1215-180 degreeC, Preferably it is 120-150 degreeC, and the pressure is 1.0-5.0 atm in absolute pressure, Preferably it is 1.0-1.9 atm. The heat melting of the crystal adduct may be accomplished using an external heating vessel.

Evaporation of phenols from the melt of the crystalline adduct can be accomplished using distillation towers or thin film evaporators. In this case, the evaporation apparatus may be multi-stage, but the heating temperature of the final stage is 160-200 ° C., preferably 170-185 ° C., and the pressure is usually 100 Torr or less, preferably 5-40, under reduced pressure. Thor pressure is employed.

Preferred evaporation removal of this phenol is accomplished by distilling most of the phenol using a thin film evaporator or the like and then removing the remaining traces of phenol by steam stripping. In this case, the supply amount of steam is 1/50 to 1/5, preferably 1/25 to 1/10 by weight relative to bisphenol A.

The product bisphenol A obtained as mentioned above has a purity of 99.95% by weight or more, and is excellent in color, and usually has a color of APHA 20 or less. Such high-quality bisphenol A is suitable as a raw material bisphenol A of high-quality polycarbonate or epoxy resin and is suitable as bisphenol A used in the optical field.

[Second process]

A second process for obtaining bisphenol A according to the invention is described below.

The raw material for the evaporation treatment used in the present invention is a mixture containing a crystalline adduct having 15 or less of the molten color APHA in neutral conditions and an aliphatic carboxylic acid.

In order to carry out the present invention preferably, the crystal adduct or its melt or mixture of the crystal adduct and the phenol value or the melt thereof is substantially melted in the presence of aliphatic carboxylic acid under neutral conditions and heated under reduced pressure to evaporate the phenol. Remove

The aliphatic carboxylic acid used in the present invention exhibits an action of preventing the coloring of bisphenol A when the bisphenol A in a molten state is brought into contact with air for a long time or kept at a high temperature. In the present invention, bisphenol A having excellent color and no coloring can be obtained by evaporating the mixture of the crystal adduct and aliphatic carboxylic acid under substantially neutral conditions and evaporating off the phenol in the crystal adduct.

The aliphatic carboxylic acid may be any one as long as it exhibits a color preventing effect with respect to bisphenol A, and conventionally known ones are used. For example, formic acid, oxalic acid, citric acid, tartaric acid, glycolic acid, lactic acid, malic acid, glycerin acid and the like can be given. Such compounds decompose or isomerize at a temperature of 160 ° C. or higher during the reaction, showing an excellent effect as a color inhibitor for bisphenol A.

As the anti-coloring agent in the present invention, it is necessary to use aliphatic carboxylic acid, and if oxalic acid ester, terephthalic acid, sodium hydrogen phosphate, etc. are used, sufficient anti-coloring effect of bisphenol A cannot be obtained. Keeping in contact with air or at high temperatures causes bisphenol A to become pigmented, which significantly deteriorates its color. The amount of aliphatic carboxylic acid added is 1 to 100 ppm by weight, preferably 5 to 50 ppm by weight, based on the crystal adduct.

In addition, in this invention, when melt | dissolving the mixture containing this crystal addition product in presence of oxalic acid or citric acid, the melting temperature is 115-180 degreeC, Preferably it is 120-150 degreeC, and melting pressure is 1-5 atm, Preferably Preferably it is 1.0-1.9 atm. The molten atmosphere is preferably an atmosphere having a low oxygen concentration, and it is advantageous to use an atmosphere having an oxygen concentration of 0.005 vol%, preferably 0.001 vol% or less.

In the present invention, in order to melt the crystal adduct or the mixture containing the same in a short time, the crystal adduct or the mixture containing the same is diluted and melted using a heat phenol having almost no coloring such as purified phenol as described above. Or a method of dissolving a crystalline adduct or a mixture containing the same in a molten liquid solution.

In the present invention, the heated melt obtained as described above is evaporated. In this case, the evaporation is carried out at 130 to 200 ° C under reduced pressure. Preferred evaporation is performed such that the temperature of the entire melt is 185 ° C. or less and at least a portion of the melt is heated to a temperature of 160 ° C. or more. If the evaporation temperature is too low, the effect of the aliphatic carboxylic acid added as a coloring inhibitor cannot be sufficiently exerted, while if it is too high, the color decomposition of the aliphatic carboxylic acid is caused. This evaporation is performed under reduced pressure and the pressure is 100 Torr or less, Preferably it is 5-40 Torr. In addition, the atmosphere of the evaporation treatment is preferably an atmosphere having a low oxygen concentration, and it is usually advantageous to use an atmosphere having an oxygen concentration of 0.005 vol% or less, preferably 0.001 vol% or less.

According to the present invention, it is possible to obtain a product bisphenol A having high purity, excellent color, and prevention of coloration during melting. Such a thing also has excellent storage stability.

[Third Process]

A third process for obtaining bisphenol A according to the present invention is described below.

The crystal adduct of bisphenol A and phenol used in this invention is manufactured by a conventionally well-known method. That is, an excess of phenol and acetone can be reacted in the presence of a strong acid catalyst to obtain a reaction product containing bisphenol A, and then crystallized by the reaction product to obtain a crystal adduct with bisphenol A. In this case, the purity of the crystal adduct may be improved by performing a crystallization process in multiple stages or by a method of washing the crystal adduct. However, when a small amount of strongly acidic material used as a catalyst in the reaction between phenol and acetone is contained in the crystal adduct. There are many. This strongly acidic substance reacts with phenol or bisphenol A under heating conditions to promote the generation of colored substances and impurities, thereby lowering the purity of the recovered bisphenol A and phenol. On the other hand, strongly acidic substances used as catalysts in the reaction of phenol and acetone are generally removed by the neutralization treatment after the reaction and also by the multi-stage crystallization process, but the removal is often incomplete and usually in trace crystalline adducts. Strongly acidic substances are mixed.

The present invention uses, as a raw material, a crystal adduct containing a small amount of strong acid. The amount of the strongly acidic substance in the crystal adduct used in the present invention is usually 0.3 meq / l or less. Such a crystal adduct is dissolved in an aqueous methanol solution adjusted to acidity so as to show pH 5.0, and pH 4.0 to 5.5, preferably pH 4.3 to 5.2 in a pH measurement method under substantially non-electrolyzed conditions of phenol. It represents. As used herein, the term "crystal adduct" under mildly acidic conditions means a crystal adduct in such a pH range.

In the present invention, the crystal adduct is used under mildly acidic conditions as described above. In this case, it is preferable to keep the molten color APHA of the crystal adduct below 15. A crystal adduct having a melting color of APHA of 15 or less can be obtained by increasing the number of crystallization stages in the crystallization step of crystallizing the crystal adduct, and also by washing the crystal adduct with purified phenol.

In order to carry out the present invention preferably, the crystalline adduct under mildly acidic conditions is melted in the presence of aliphatic carboxylate, and heated under reduced pressure to evaporate phenol off.

The aliphatic carboxylic acid salt used in the present invention reacts with the trace amount of strongly acidic substance incorporated into the crystal adduct, and neutralizes it and at the same time by-produces the aliphatic carboxylic acid liberated by the neutralization reaction. Therefore, in the present invention, when the crystal adduct is melted and evaporated in the presence of an aliphatic carboxylate, bisphenol A having excellent color can be obtained since there is no strong acidic substance which reacts with phenol and bisphenol A to produce colored substances and impurities. Due to the anti-coloring effect of the by-produced free carboxylic acid, the resulting bisphenol A is such that the coloring of the melt is remarkably suppressed.

As the aliphatic carboxylate, any one can be used as long as it can react with a strongly acidic substance, but alkali metal salts, ammonium salts and alkaline earth metal salts are generally used. As the aliphatic carboxylic acid component of the aliphatic carboxylate, those having an anti-coloring effect on bisphenol A are preferably used, and conventionally known ones such as formic acid, oxalic acid, citric acid, tartaric acid, glycolic acid, lactic acid, malic acid, glycerin acid, and the like. Can be mentioned. These aliphatic carboxylates decompose or isomerize at a temperature of 160 ° C. or higher during the reaction, and exhibit an excellent effect as a color inhibitor for bisphenol A. The amount of aliphatic carboxylate added is the amount that substantially neutralizes the crystal adduct, that is, the amount of neutralization of the strongly acidic substance.

The addition of more carboxylic acid salts than this neutralization equivalent is undesirable, and a large amount of carboxylic acid salts deteriorates the color of the product bisphenol A. When carboxylate is added, free carboxylic acid may be added together with the carboxylate when the amount of by-product free carboxylic acid is small and the coloring prevention effect by the free carboxylic acid is small. The amount of the free carboxylic acid added is 0.1 to 50 wt ppm, preferably 1 to 30 wt ppm, based on the crystal adduct including the byproduct free carboxylic acid. In the case of heating and melting the crystal adduct in the presence of a carboxylate, the melting temperature thereof is 115 to 180 占 폚, preferably 120 to 150 占 폚, and the melting pressure is 1 to 5 atm, preferably 1.0 to 1.9 atm. The molten atmosphere is preferably an atmosphere having a low oxygen concentration, and usually an atmosphere having an oxygen concentration of 0.005 vol% or less, preferably 0.001 vol% or less is advantageous. In the present invention, in order to melt the crystal adduct in a short time, the crystal adduct is diluted and melted using a heat phenol having almost no coloring such as the above-described purified phenol, or the melting of the crystal adduct is completed. The method of making it melt | fuse in a liquid flow can also be employ | adopted.

In the present invention, the heated melt of the crystal adduct to which the aliphatic carboxylate is added is evaporated. In this case, the evaporation is carried out at 130 to 200 ° C under reduced pressure. Preferred evaporation is carried out such that the temperature of the entire melt is 185 ° C. or less and at least a portion of the melt is subjected to heating at a temperature of 160 ° C. or more. If the evaporation temperature is too low, it will not be possible to sufficiently exhibit the anti-coloring effect of the by-produced aliphatic carboxylic acid in the reaction between the strongly acidic substance and the aliphatic carboxylate, while if too high, the color decomposition of the aliphatic carboxylic acid will be caused. This evaporation process is performed under reduced pressure, and the pressure is 100 Torr or less, Preferably it is 5-40 Torr. In addition, the atmosphere of the evaporation treatment is preferably an atmosphere having a low oxygen concentration, and it is usually advantageous to use an atmosphere having an oxygen concentration of 0.005 vol% or less, preferably 0.001 vol% or less.

According to the present invention, it is possible to obtain a product bisphenol A which is high in purity and excellent in color, and prevents coloration during melting. Such a thing also has excellent storage stability.

[Fourth process]

A fourth process for obtaining bisphenol A according to the present invention is described below.

The crystal adduct used in the present invention has a melt color APHA of 15 or less, preferably 10 or less. Such a crystal addition product can be obtained by multistage crystallization of a phenol solution containing bisphenol A. In addition, the crystal adduct obtained by crystallizing the phenol solution containing bisphenol A is washed with purified phenol from which the above coloring agent is removed to obtain bisphenol A. It is presented about the process.

The crystal adduct obtained as described above is treated by using a phenol removal apparatus system from the crystal adduct including the melting apparatus and the evaporation apparatus, but in the present invention, at least one of the crystal adducts previously included in the phenol removing apparatus prior to the treatment. Oxygen removal processing adhering to the surface of the material which comprises an inner wall surface is performed to this melting apparatus and the evaporation apparatus.

The inner wall surface of the melting apparatus and the evaporation apparatus is formed of a metal material, usually stainless steel, such as SUS 304, SUS 316, 316L, etc., on the surface of which is usually bonded with oxygen of about 30 to 60 millimoles per square meter. . This oxygen amount can be measured by various methods. For example, there is also a method of obtaining and estimating the correlation between the cleaning conditions and the amount of surface-bonded oxygen measured by the surface etching by the test piece, but can also be measured from the relationship between the amount of surface-bonded oxygen and the coloring of the cleaning phenol. Also in the case of other cleaning liquids, the correlation between the coloring and the amount of surface-bonded oxygen can be determined in advance and used as a measuring method. For example, coloring of phenol becomes 6 APHA per 1 part by weight of oxygen, and can be used as a correlation of this measurement. According to the researches of the present inventors, when the melter and the evaporator are used by removing the oxygen adhering to the inner wall surface in advance, the melting agent and the evaporator are remarkably produced by the melting of the crystal adducts and the generation of the coloring causative material generated by heating in the evaporation of the melt. It was found that the product bisphenol having good color can be obtained by suppressing it.

Oxygen removal from the inner wall surface of the melting apparatus and the evaporation apparatus can be achieved by washing the inner wall surface with an organic solvent. As the organic solvent, phenol or bisphenol A, a mixture of phenol and bisphenol A, and the like can be used. The washing treatment temperature is 100 to 200 ° C, preferably 120 to 185 ° C. As the atmosphere for cleaning, a non-acidic gas atmosphere such as nitrogen gas, nitrogen gas, argon gas, or degassed vapor, or a reduced pressure atmosphere is used, and the oxygen concentration in the atmosphere is 0.01 vol% or less, preferably 0.005 vol% or less. More preferably, it is 0.001 vol% or less. The cleaning of the inner wall surface by the organic solvent can be achieved by spraying the organic solvent on the inner wall surface through a spray nozzle. After washing with the organic solvent, the organic solvent remaining in the bottom of the melting apparatus and the evaporation apparatus is discharged, and the interior is dried as necessary. In addition, a trace oxygen analyzer by a conventional gas chromatography method or an electrochemical method can be used for the measurement of the concentration of the gaseous oxygen.

In the oxygen removal treatment from the inner wall surface, the amount of oxygen adhering to the inner wall surface is 10 millimoles or less, preferably 5 millimoles or less per 1 m 2 of the inner wall surface.

As the melting apparatus, an external heating hermetic container having a heating jacket on the outer wall surface, or an internal heating hermetic container having a heating coil inside is used. Distillation column, stripping device, centrifugal thin film evaporator is used as the evaporator.

A pipe is provided between the melting apparatus and the evaporator, and a discharge pipe of bisphenol A is provided in the evaporator. In the present invention, the oxygen removal treatment is preferably performed on the inner wall surface of these pipes in the same manner as described above.

In the present invention, at least the melting apparatus and the evaporation apparatus included in the apparatus system as described above are subjected to the oxygen removing treatment of adhering to the inner wall surface thereof, and then the crystal additives are supplied to the apparatus system and the crystal addition is performed in the melting apparatus. Water is melted, and the obtained melt is evaporated by an evaporator to evaporate phenol.

The operating conditions of the melting apparatus are temperature: 115 to 180 ° C, preferably 120 to 150 ° C, pressure: atmospheric pressure, oxygen concentration: 0.01 vol% or less, preferably 0.005 vol% or less, and more preferably 0.001 vol% or less. Conditions are employed. The evaporator may be used in one stage or in multiple stages, but in the case of using in one stage, in the case of using in one stage of evaporation apparatus and in multiple stages, the operating conditions of the evaporator of the final stage are 180 to 200 ° C, preferably 170 to 185 DEG C, pressure: 1 to 100 torr, preferably 5 to 40 torr, oxygen concentration in the atmosphere: 0.005 vol% or less, preferably 0.001 vol% or less.

According to the present invention, the amount of the colored causative agent due to the melting of the crystal adduct and the heating of the melt in the evaporation process can significantly suppress the amount of production, thereby obtaining a high-purity bisphenol A having good color.

[The fifth process]

A fifth process for obtaining bisphenol A according to the present invention is described below.

As the crystal adduct used in the present invention, various crystal adducts presented with respect to the fourth process of the present invention presented for obtaining bisphenol A are used.

The crystalline adduct used as a raw material in the present invention is melted together with phenol attached or entrained therein, and then led to an evaporation process consisting of an evaporation tower in which a member for improving at least one evaporation surface area is disposed therein. In the present invention, the oxygen adhering to the inner wall surface of the evaporation tower and the surface of the member for improving the evaporation surface area is removed prior to the start of operation of the evaporation tower.

The inner wall of the evaporation tower and the member for improving the evaporation surface area, for example, the surface of the metal constituting the filler or the rack stage, are formed of ordinary stainless steel, for example, SUS 304, SUS 316, SUS 316L and the like. About 30 to 60 millimoles of oxygen per 1 m 2 are attached and bonded. According to the researches of the present inventors, when the evaporation tower is used by removing the oxygen adhering to the metal surface in advance, it is possible to remarkably suppress the generation of a coloring causative material caused by the heating in the evaporation treatment of the crystal adduct, and the color is good. It was also found that a product bisphenol A, in which the change in color over time is suppressed can be obtained.

Oxygen removal from the inner wall surface of the evaporation tower and the surface which improved the evaporation surface area, for example, the filler surface, can be achieved by cleaning the surface with an organic solvent. As the organic solvent, phenol and / or bisphenol A, a mixture of phenol and bisphenol A, and the like can be used. The washing process temperature is 100-200 degreeC, Preferably it is 120-185 degreeC. As an atmosphere for cleaning, an atmosphere having an oxygen concentration of 0.1 vol% or less, preferably 0.05 vol% or less is used, such as an inert gas such as nitrogen gas, argon gas or degassing steam atmosphere. The cleaning of the inner wall surface of the evaporation tower and the surface of the member which improves the evaporation surface area by the organic solvent can be achieved by spraying a container solvent on the surface through a spray nozzle, and also by distributing the organic solvent into the evaporation tower.

In the oxygen removal treatment, the amount of oxygen adhering to the inner wall surface of the evaporation tower and the surface of the member for improving the evaporation surface area is 10 millimoles or less, preferably 5 millimoles or less per square meter of surface area.

In the present invention, the oxygen removal treatment is applied not only to the inner wall surface of the evaporation tower and to the member surface for improving the evaporation surface area, but also to melt other metal surfaces such as crystal adducts contacted by the crystalline adduct melt or the bisphenol A melt. It is preferable to apply to the inner wall surface of the melting apparatus, the inner wall surface of the piping between the melting apparatus and the evaporation tower, and moreover, the inner wall surface of the bisphenol A extraction piping provided in the evaporation tower.

In the present invention, the crystal adduct is heated and melted to form a molten liquid, and then supplied to an evaporation tower, where the phenol is evaporated and removed.

As the melting apparatus of the crystal additive, an external heating hermetic container having a heating jacket on the outer wall surface, an internal heating hermetic container having a heating coil inside, or the like is used.

The operating conditions at the time of melting the crystal adduct are generally temperature: 115 to 180 ° C, preferably 120 to 150 ° C, pressure: 1.0 to 5.0 atm (absolute pressure), preferably 1.0 to 1.9 atm (absolute pressure). Conditions are employed. Further, the oxygen concentration in the molten atmosphere of the crystal adduct is maintained at 0.005 vol% or less, preferably 0.001 vol% or less. In the present invention, in order to melt the crystal addition product in a short time, the crystal addition product is diluted or melted using a heat phenol having almost no coloring such as the above-described purified phenol, or the melting of the crystal addition product is finished. It is also possible to employ a method of melting in a liquid flow.

As an evaporation tower, the thing which provided the member which improves the evaporation surface area at least inside the cylinder body whose inner wall surface is formed from metal material especially stainless steel, for example, SUS304, SUS 316, SUS 316L, etc. is also used. This evaporation tower can provide heating means at its bottom. As a member for improving the evaporation surface area, a conventionally known filler, a cache end, a wet wall, or the like can be proposed, and these can be used alone or in combination. In this case, it is composed of a filler, a cache end, a wet wall member material, a metal material such as stainless steel such as SUS 304, SUS 316, and SUS 316L.

In addition, the filling material may be a rasching ring, a falling ring, a plate, or a perforated plate, and the tray of the cache stage is a bubble type, a perforated plate type, and the tray is down. It may be equipped with a killer.

The evaporation tower is used in combination of at least one, preferably two or more. This evaporation tower may be an evaporation tower (vapor stripping evaporation tower) using steam. Preferred evaporation of the crystalline adduct melt according to the invention is achieved using a combination of a conventional evaporation tower without steam and a vapor stripping evaporation tower using steam.

Next, a method of evaporating the crystalline adduct melt using an evaporation treatment system comprising a first evaporation tower not using steam and a second evaporation tower using steam will be described in detail.

In this evaporation treatment method, the molten liquid from the crystal addition product melting apparatus is introduced into the first evaporation tower and evaporated therein in the absence of steam and under reduced pressure, to evaporate a part of phenol in the melt. From the top of the first evaporation tower, steam containing phenol is separated and recovered, and from the bottom, a portion of the phenol is separated and recovered by evaporation of the molten liquid. The bottoms from the first evaporation tower are introduced into the second evaporation tower, where the evaporation is carried out in the presence of steam and under reduced pressure, and the residual phenol in the melt is evaporated off. From this second evaporation tower, a mixed vapor containing phenol, steam, and a small amount of bisphenol A is discharged as the tower top, and high purity bisphenol A is separated and recovered as the column bottoms.

As operating conditions of the first evaporation tower not using steam, a temperature of 125 to 200 ° C, preferably 130 to 185 ° C and a pressure of 100 Torr or less is preferably employed, preferably 5 to 40 Torr. The oxygen concentration in the vapor atmosphere in the evaporation tower is maintained at 0.005 vol% or less, preferably 0.001 vol% or less. In this first evaporation column, 95 to 99.8% by weight, preferably 98 to 99.7% by weight, of the phenol present in the crystal addition product melt is evaporated off.

The operating conditions of the second evaporation tower using the above steam include: temperature: 130 to 200 ° C, preferably 160 to 186 ° C, pressure of 100 torr or less, preferably 5 to 40 torr, and steam supply amount per 1 kg of bisphenol A melt: 0.02 to 0.2 kg, preferably 0.04 to 0.1 kg is employed. The oxygen concentration in the vapor atmosphere in the evaporation tower is maintained at 0.005 vol% or less, preferably 0.001 vol% or less. In this second evaporation column, substantially the entire amount of phenol in the crystalline addition product melt obtained in the first evaporation column is evaporated off, and bisphenol A having a phenol content of 200 wt ppm or less, preferably 50 wt ppm or less is obtained as the bottoms. Lose.

From the second evaporation column using the above steam, a mixed vapor containing steam, phenol and a small amount of bisphenol A is obtained, but phenol and bisphenol A are separated and recovered from this mixed steam. Separation and recovery of phenol and bisphenol A from this mixed steam can be carried out by various conventionally known methods, but in the present invention, in particular, by using a condensation method of a stripping gas comprising a two-step cooling step described later, It is preferable to carry out.

According to the present invention, the evaporation treatment of the crystalline adduct melt can be carried out by using an evaporation tower having a large evaporation surface area under reduced pressure, so that the evaporation treatment can be carried out with good efficiency. Furthermore, in this case, the evaporation tower is formed by using an oxygen removal treatment on the inner wall surface and the member surface disposed inside in advance, so that the amount of the coloring causing substance due to heating in the evaporation of the melt can be reduced. It is possible to obtain high purity bisphenol A which can be remarkably reduced, excellent in color, and in which the color of the melt significantly reduces the change over time.

[The sixth process]

The sixth process for obtaining bisphenol A by this invention is demonstrated below.

As the crystal adduct used in the present invention, various crystal adducts described in relation to the fourth process of the above invention indicated to obtain bisphenol A are used.

Next, a sixth process of the present invention will be described with reference to FIG.

In FIG. 6, (1), (2), and (3) represent a thin film evaporator. This is a structure of evaporating the thin film formed in the inner peripheral wall by heating from the outside. In the present invention, it is preferable to use a centrifugal thin film evaporator which has a rotary blade inside and which forms a liquid film on the inner peripheral wall surface in accordance with the rotation of the rotary blade.

In Fig. 6, reference numeral 4 denotes an external heater attached to each thin film evaporator. This is usually configured as a jacket through which the heating medium flows.

In this invention, the crystal addition product used as a raw material melts this by heating, or dilutes it with refined phenol, and makes it the phenol solution containing bisphenol A. The phenol solution preferably used in the present invention has a color of APHA 15 or less and a bisphenol A concentration of 50 to 80% by weight, preferably 60 to 75% by weight.

This raw phenol solution is introduced into the first thin film evaporator (hereinafter also referred to simply as the evaporator) 1 in line 10, and the phenol solution flows down the inner circumferential wall of the evaporator as a liquid film, and the different external heater ( Heated by 4) and discharged past the vapor line 11 containing phenol and bisphenol A. This steam condenses it to recover phenol and bisphenol A.

The temperature of the phenol solution passing through line 10 is preferably 120 to 150 ° C. The temperature of the first evaporator 1 is 160 to 185 ° C, preferably 165 to 175 ° C, and the pressure is 15 to 60 torr, preferably 15 to 30 torr.

In the first evaporator 1, the remaining liquid (bisphenol A) obtained by evaporating the raw phenol solution is extracted through the line 12 and introduced into the second evaporator 2. The temperature of the evaporated balance of the phenol solution passing through line 12 is preferably 170 to 185 ° C. Moreover, the phenol concentration is 1 to 5 weight% in bisphenol A which comprises this balance.

In the second evaporator (2), bisphenol A is heated by the external heater (4) in countercurrent contact with a stripping gas consisting of steam, phenol and bisphenol A extracted from the third evaporator (3), phenol bisphenol A and Stripping gas containing steam is discharged past line 13.

The temperature in the 2nd evaporator 2 becomes like this. Preferably it is 170-185 degreeC, and a pressure is 15 Torr or less, Usually, 10-15 Torr.

The evaporation balance obtained from the second evaporator 2 is introduced into the third evaporator 3 via the line 14. Preferably the temperature of this residue is 170-185 degreeC, and the phenol concentration in bisphenol A which comprises a balance is 0.05-0.10 weight%, Preferably it is 0.05-0.07 weight%.

In the third evaporator (3), the bisphenol A from the second evaporator (2) is heated by the external heater (4) in countercurrent contact with the vapor introduced through the line (15), and the stripping gas is lined. Extracted after (17), this stripping gas is introduce | transduced into the 2nd evaporator 2 as the stripping gas. The temperature in the third evaporator is 170 to 185 ° C, and the pressure is 15 torr or less, usually 10 to 15 torr. The amount of steam introduced into the third evaporator 3 in the line 15 is 3% by weight or more, preferably 4 to 6, in terms of weight relative to the bisphenol A introduced into the third evaporator 3 through the line 14. Weight percent. The composition of the stripping gas passing through the line 17 is 0.8 to 1.2 wt% of phenol, preferably 1 wt% or less, bisphenol A: 5 to 7 wt%, and the balance: steam.

The high purity bisphenol A obtained in the third evaporator 3 is extracted after the line 16. This bisphenol A has a phenol content of 0.005 wt%, and the color APHA has a high quality of 20 or less.

In the stripping gas discharged from the second evaporator 2 past the line 13, the phenol and bisphenol A contained in the gas are separated and recovered by using a condensation treatment.

Although the stripping gas can be condensed by a conventionally known method, it is particularly preferable to carry out using the condensation method of the stripping gas, which consists of a two-step cooling process described later.

In the present invention, a phenol solution containing bisphenol A derived from bisphenol A-phenol crystal adduct is first evaporated using a first thin film evaporator to obtain bisphenol A having a phenol content of 1 to 5% by weight. In the present invention, while maintaining the temperature of the first thin film evaporator at a condition of 160 to 185 ° C. and a pressure of 15 to 60 Torr, bisphenol A does not precipitate smoothly even if cooling due to rapid evaporation of phenol occurs. The evaporation process can be performed.

In the present invention, the bisphenol A obtained as described above is subjected to steam stripping treatment using a thin film evaporator in order to evaporate and remove the phenol contained therein. Since it is low as 5% by weight and two thin film evaporators are used in series, the temperature of these evaporators is maintained at 170 to 185 ° C., and is maintained at a high vacuum of 15 Torr or less to evaporate the phenol in the bisphenol A. It is possible to obtain a high-purity bisphenol A with a phenol content of 0.005% by weight or less while being excellent in color.

In order to obtain bisphenol A which is excellent in color, the phenol solution containing bisphenol A which is the manufacturing raw material, and the temperature at the time of evaporating this solution are maintained at 185 degreeC or less, and generation | occurrence | production of colored impurities, such as isopropenyl phenol, is carried out. In the case of the present invention, since bisphenol A is substantially completely evaporated and removed by maintaining the evaporation temperature at 185 ° C. or lower, the resulting bisphenol A has a high purity of APHA 20 or less. .

Further, in the present invention, a stripping gas composed of steam containing phenol and bisphenol A produced in the third thin film evaporator is used as the stripping vapor gas for the second thin film evaporator, whereby the phenol strip in the second thin film evaporator is used. There is also an advantage that the ping effect is increased.

According to the evaporation treatment of the present invention, since the evaporation treatment can be performed in a very short residence time (usually 60 to 180 seconds) as a whole, the treatment efficiency is very high. In particular, in the case of the present invention, it is preferable to combine the first thin film evaporator, the second thin film evaporator, and the third thin film evaporator in the order from the top, and to flow the liquid flow from the top to the bottom by gravity, thus oxygen The leaf can be effectively prevented and the residence time of the liquid in the system can be kept short.

[Seventh process]

The seventh process for obtaining bisphenol A by this invention is demonstrated below.

As the crystal addition product to be used in the present invention, a substance having a melt color of 15 APHA or less, preferably 10 APHA or less, under substantially neutral conditions indicated in relation to the first process of the present invention indicated to obtain bisphenol A. Used.

In the present invention, a solution containing bisphenol A, which is formed under crystal additives having a melting color of 15 APHA or less under substantially neutral conditions, is subjected to evaporation and removal of phenol under reduced pressure using a thin film evaporator under substantially anoxic. Process. In this case, substantially oxygen free means that the oxygen concentration in the atmosphere in the apparatus system for evaporating and removing phenol is 0.005 volume ppm or less. As a method of bringing the inside of the apparatus system into such an oxygen free state, there is a method of purging an inert gas such as nitrogen gas or argon gas in the apparatus system, and more preferably, the step of depressurizing the interior of the apparatus system and the reduced pressure. There is a method of repeatedly carrying out the step of purging the inert gas in the system.

In the case of evaporating off phenol from a solution containing bisphenol A formed from a specific crystal adduct according to the present invention, a coloring inhibitor may be added if necessary. This anti-coloring agent can directly participate in the crystalline adduct, in which case the anti-coloring agent is added and mixed to the crystalline adduct in any state, i.e., the crystalline adduct in powder, molten, slurry or solution state. You can.

In this invention, the coloring inhibitor which can be used preferably is an aliphatic carboxylic acid. This aliphatic carboxylic acid exhibits the effect of making bisphenol A in a molten state contact with the air for a long time or preventing coloring of bisphenol A when kept at a high temperature.

As aliphatic carboxylic acid, any thing can be used as long as it exhibits a coloring prevention effect with respect to bisphenol A, and a conventionally well-known thing is used. As such a thing, formic acid, oxalic acid, citric acid, tartaric acid, glycolic acid, lactic acid, malic acid, glycerin acid, etc. are mentioned, for example. These cause decomposition or isomerization at the temperature of 160 degreeC or more during reaction, and show the outstanding effect as a coloring inhibitor to bisphenol A. The addition amount of aliphatic carboxylic acid is 1-100 weight ppm with respect to a crystal addition product, Preferably it is 5-50 weight ppm.

By addition of this aliphatic carboxylic acid, the product bisphenol A which is good in thermal stability with which coloring was prevented at the time of melting can be obtained.

This invention can be implemented similarly to the case of the said 6th process of this invention using the apparatus system shown in FIG.

[Eighth process]

The eighth process for obtaining bisphenol A by this invention is shown below.

The stripping gas used as the raw material to be treated in the present invention is a gas obtained when stripping a mixture of phenol and bisphenol A with steam, and is composed of phenol, bisphenol A and steam. As such a stripping gas, for example, a stripping gas discharged from the line 13 shown in FIG. 6 can be used.

In the present invention, the stripping gas is supplied to the first cooling step as it is under reduced pressure, and is cooled by making a countercurrent connection with the first cooling medium made of phenol or phenol containing bisphenol A. This first cooling step is carried out so that substantially the entire amount of bisphenol A in the stripping gas is dissolved in the cooling medium. The vapor in the stripping gas is hardly condensed in this first cooling process, and is sent to the next second cooling process. Some of the phenol in the stripping gas is condensed in this first cooling process and the remaining uncondensed is sent to the next second cooling process with steam. The bisphenol A and phenol mixture liquid separated and recovered by the stripping gas in the first cooling process can use a part thereof as a cooling medium.

The temperature of the first cooling medium is about 1 to 50 ° C. higher than the freezing point of phenol.

The recovery rate of phenol in this first cooling step is 70% by weight or more, preferably 85% by weight or more, relative to the pre-feed phenol for this first cooling step.

The cooling medium used in the first cooling step may be an amount sufficient to cool the stripping gas to a desired temperature, and is usually 5 to 10, preferably 5 to 6, by weight to the stripping gas. The weight ratio of bisphenol A in the stripping gas obtained in the first cooling step to bisphenol A contained in the cooling medium in which phenol is dissolved is 0.05 to 0.02, preferably 0.08 to 0.14. In the 1st cooling process, since excess phenol exists with respect to bisphenol A, even if it is cooling temperature below the freezing point of bisphenol A, the crystal adduct of bisphenol A and phenol does not crystallize.

The pressure of the first cooling process is 30 Torr or less, preferably 5 to 20 Torr, and corresponds to the pressure in the second thin film evaporator 2. In addition, the temperature of a 1st cooling process is the temperature which steam value maintains and a part of phenol keeps a liquid under the said pressure conditions. Preferable cooling temperature (temperature which condenses bisphenol A) is 1-50 degreeC higher than the freezing point of a phenol, and its cooling temperature is 42-90 degreeC, Preferably it is 45-55 degreeC.

The mixed gas of steam and phenol sent to the second cooling step is cooled by being brought into countercurrent contact with a second cooling medium made of an aqueous solution of phenol. This 2nd cooling process is performed so that the substantially whole quantity of the vapor | steam and phenol sent to this process may be condensed, and in this process, the aqueous solution of phenol will be collect | recovered. A part of the aqueous solution of phenol obtained in this second cooling step can use a part thereof as the second cooling medium. The concentration of phenol in the aqueous solution is determined by the composition of the stripping gas and the conditions of the first cooling step, but is usually 55 to 75% by weight. Moreover, the temperature of this 2nd cooling medium is a temperature about 1-10 degreeC lower than the steam condensation temperature.

The second cooling medium used in the second cooling step may be an amount sufficient to condense the entire amount of the mixed gas, and is usually 100 to 300, in a weight ratio to the mixed gas of vapor and phenol sent in the first cooling step. Preferably 190-250. The pressure of this 2nd cooling process is 30 Torr or less, Preferably it is 5-20 Torr, and respond | corresponds to the pressure of a 1st cooling process. The cooling temperature (steam condensation temperature) in a 2nd cooling process should just be a temperature at which the whole quantity of the mixed gas of steam and a phenol condenses under the said pressure conditions.

The cooler used in a 1st cooling process and a 2nd cooling process should just be a gas-liquid contact type apparatus, and arbitrary things are used. As such a cooler, a packed tower, a spray tower, etc. can be used, for example. In the case of using a packed column, as the filler, it is preferable to use a Rashihi ring, a polling, a porous metal plate or the like so as to suppress pressure loss. In addition, although the coolers used by a 1st cooling process and a 2nd cooling process may be respectively provided separately, the 1 tower type apparatus containing two coolers may be sufficient. Next, an embodiment of the above condensation treatment method for stripping gas will be described with reference to the drawings.

In Fig. 7, reference numeral 21 denotes the first cooler and reference numeral 22 denotes the second cooler. Line 23 represents a stripping gas line connecting to line 13 shown in FIG. Line 24 is a vacuum line connecting to an exhaust pump (not shown) and a cooler, and the entire electric system including the cooler is maintained under reduced pressure.

The stripping gas is fed to the lower part of the first cooler 21 via line 23, where it is introduced into the first cooling medium (phenol or bisphenol A, which is introduced at the top of the first cooler beyond line 25). Phenol)) in countercurrent contact. The cooling medium in which bisphenol A condensed in the first cooler and phenol are dissolved is drawn out from the bottom of the first cooler after passing through the line 26 containing the discharge pump 27. The cooling medium discharged past this line 26 may be partially recycled to the line 25 as a cooling medium after cooling a portion thereof to a required temperature if necessary.

At the top of the first cooler 21, a mixed gas of steam and phenol, which is drawn off through the line 28, is introduced into the lower part of the second cooler 22 and here from the top of the second cooler past the line 29. Countercurrent contact with the introduced second cooling medium (aqueous solution of phenol) In this second cooler, the mixed gas of steam and phenol is condensed, and this condensate is drawn out at the bottom of the second cooler 22 together with the cooling medium and past the line 30 including the pump 31 and Some pass over line 33, cool past cooler 34 for the cooling medium, then pass over line 29 and are recycled to the second cooler. The remainder of the cooling medium containing condensate vapor and phenol extracted via line 30 is drawn out of system beyond line 32.

Next, in the condensation treatment method of the stripping gas, a flow sheet in the case of using a one-top cooling device including a first cooler and a second cooler is shown in FIG.

In Fig. 8, reference numeral 50 denotes a tower cooling device having a first cooler 21 and a second cooler 22 at its nap. This cooling device has a structure in which a partition plate 45 having an opening in the center is disposed in the middle between the first cooler 21 and the second cooler 22, and a cylinder 43 is placed in the opening. Have In this apparatus, the annular hollow chamber formed between the outer circumferential surface of the cylindrical body 43 and the inner wall of the cooling device 50 is for storing liquid. Reference numeral 42 is a guide plate for guiding the liquid flowing down the second cooler 22 to the annular hollow chamber. Normal space 44 represents a gas passage.

In addition, in the code | symbol of FIG. 8, the same code | symbol as shown in FIG. 7 shows the same meaning. 8, the flow control system shown in FIG. 7 is not shown in figure.

According to the condensation treatment of the stripping gas, the stripping gas can be cooled under a reduced pressure of 30 Torr or less without boosting the stripping gas. Moreover, in this case, despite adopting a low pressure condition of 30 Torr or less and thus a low steam condensation temperature condition, crystals of bisphenol A or phenol are not precipitated at all. Therefore, in this condensation treatment method of the stripping gas, solid precipitation does not reduce the efficiency of the cooler or cause a problem of closing the cooler.

Further, according to the condensation treatment of the stripping gas, all of steam, phenol and bisphenol A constituting the stripping gas are condensed, and their gas is not substantially introduced into the vacuum exhaust machine. Therefore, the vacuum exhaust pump is advantageous because only the apparatus system is maintained at a predetermined decompression condition, the exhaust capacity is small, and the equipment cost and energy cost are small.

EXAMPLE

Next, the present invention will be described in more detail with reference to Examples.

[A: Purification of Crystal Additives]

Example A-1

A commercial industrial phenol (water concentration of 0.1 wt%, impurity concentration of 0.05 wt%) was contact-treated at 80 DEG C and a contact time of 150 minutes using Amberlite IR-118 H + resin manufactured by Andas Corporation, and the distillation column bottom temperature was 175 DEG C, Distillation was carried out at a column constant pressure of 560 Torr to obtain a purified phenol of molten color 6 APHA.

On the other hand, a mixture of bisphenol A, phenol and impurities, which are molten color 50 APHA obtained by reacting phenol and acetone in the presence of an acid catalyst, was crystallized to precipitate a crystal adduct.

Next, the slurry of this crystal adduct was filtered under reduced pressure to obtain a solid crystal adduct, and the resultant was washed using the purified phenol obtained above at a ratio of 2.5 parts by weight based on 1 part by weight of the crystal adduct. The crystal adduct thus obtained was steam stripped at 175 DEG C and 25 Torr for 30 minutes to substantially completely remove phenol to obtain bisphenol A. The melt color (APHA) of this bisphenol A was 15 and extremely good in color. The number of melt colors (APHA) is ASTM. It was measured according to D 1686 (Standard Test Method for Color of Solid Aromatic Hydrocarbons and Related Materials in the Molten State).

Comparative Example A-1

A mixture of bisphenol A, phenol and impurities, which is a molten color 50 APHA, was crystallized to precipitate a crystal adduct. The slurry of this crystalline adduct was filtered under reduced pressure, the solid crystalline adduct was obtained, a part of it was decomposed at 190 degreeC, and phenol was collect | recovered. This phenol was wash | cleaned using the ratio of 2.5 weight part with respect to 1 weight part of remaining crystal adducts. The washing crystal adduct thus obtained was steam stripped at 175 DEG C and 25 Torr for 30 minutes to substantially remove all of the phenol to obtain bisphenol A, but this was a melt color of 20 APHA. Moreover, the color when this bisphenol A was kept at atmospheric pressure for 5 hours after melting was 80 APHA.

Comparative Example A-2

When distilling purified phenol, the distillation column bottom temperature was 200 degreeC and it carried out similarly to Example A-1, and obtained phenol. Bisphenol A was obtained in the same manner as in Example A-1 using this phenol as a washing liquid for the crystal addition product, but this was a melt of 30 APHA.

The molten color at 175 degreeC of the bisphenol A obtained by said Example A-1 and Comparative Examples A-1 and A-2 is put together in the following table, and is shown.

Example A-2

An industrial phenol having a water concentration of 0.07 wt% and an impurity concentration of 430 wt ppm was subjected to contact treatment at a temperature of 80 ° C. and a contact time of 20 minutes using Amberlite IR-118H + resin manufactured by Rohm Amdhath Corporation. Next, the obtained contact treated material was distilled at the distillation column bottom temperature of 173 degreeC, and column top pressure 560 Torr, and the refined phenol was obtained.

Comparative Example A-3

The experiment was carried out in the same manner as in Example A-2, except that industrial phenol having a water concentration of 0.73 wt% and an impurity concentration of 430 wt ppm was used.

The properties of the purified phenol obtained as described above are shown in Table A-2 together with the properties of the raw material industrial phenol and the phenol after ion exchange resin treatment.

Example A-3

Although the ion exchange resin treatment shown in Example A-2 was continuously performed for 1000 hours, in this case, benzofuran, which is a compound representing impurities, was not detected in the phenol after the treatment.

Example A-4

After reacting phenol and acetone in the presence of an acid catalyst, bisphenol A, a melt color 50 APHA obtained by evaporating most of the produced water and a part of phenol from the reaction product obtained, is crystallized by crystallization. Precipitated. The crystalline adduct slurry solution was filtered under reduced pressure, and the purified phenol obtained by the method described below was washed using 2.5 parts by weight based on 1 part by weight of the adduct. The crystal adduct thus obtained was steam stripped at 175 ° C. and 25 Torr for 30 minutes to substantially completely remove phenol to obtain bisphenol A. The molten color of this bisphenol A was 10-15 APHA, and the color was extremely good. Moreover, it was confirmed that the color when this bisphenol A was kept at atmospheric pressure for 5 hours after melting was 30 APHA, and it was low in colorability.

In addition, the purified phenol used above is melt color 5 APHA, which is obtained by dehydrating the above-mentioned phenol from the reaction product with acetone by dehydration (water concentration of 0.1 wt%). It was obtained by contact treatment with a light IR-118H + resin at a temperature of 80 ° C. and a contact time of 50 minutes, followed by distillation at a column bottom temperature of 175 ° C. and a tower static pressure of 560 Torr.

[B: Manufacturing Method of Crystal Additives]

Example B-1 (second process)

According to the apparatus flow diagram shown in FIG. 2, in the phenol solution containing bisphenol A, the slurry containing crystal addition product was obtained, and the crystal addition product was collect | recovered separately from this slurry. The relationship with the line or apparatus which indicated main operation conditions in this case by the code | symbol in FIG. 2 is shown below.

(1) Component Composition of Feedstock in Line (1)

Bisphenol A: 22% by weight

Phenolic: 74 wt%

Other: 4 wt%

(2) Crystal Tower A

(Ⅰ) Temperature: 54 ℃

(Ii) Residence time: 120 minutes

(3) Melt tank of microadducts attached to crystal tower A

(Iii) temperature 55 ℃

(Ii) Residence time: 6 minutes

(4) crystal tower B

(Iii) Temperature: 47 ℃

(Ii) Residence time: 120 minutes

(5) Crystalline adduct dissolving tank attached to crystal tower B

(Ⅰ) Temperature: 48 ℃

(Ii) Residence time: 6 minutes

In the above experiments, the color of the crystal adduct separated from the slurry obtained through the line 35 was 15 APHA, and the content rate of the particulate component having a particle size of 10 μm or less in the crystal adduct was 13% by weight.

Comparative Example B-1

In the apparatus system shown in FIG. 2, the crystal addition product slurry was manufactured using only the crystal tower A of the 1st stage. In this case, the operating conditions of the crystallization tower A were the same as in the case of Example B-1 except that the temperature was 47 ° C and the temperature of the microcrystalline adduct dissolution tank Q placed in the crystallization tower A was 48 ° C. .

The color of the crystal addition product obtained by this experiment was 30 APHA, and the ratio of the microparticle component of 100 micrometers or less in particle size in the crystal addition product was 29 weight%.

Example B-2 (Third Process)

According to the apparatus flow diagram shown in FIG. 3, the slurry containing a crystal addition product was obtained from the phenol solution containing bisphenol A, and the crystal addition product was collect | recovered and recovered from this slurry. In Fig. 3, the main operation conditions in this case are shown below in relation to the line indicated by the reference sign or the device.

(1) Composition of Feedstock in Line (8)

Bisphenol A: 22% by weight

Phenolic: 74 wt%

Other: 4 wt%

(2) Crystal Tower A

(Ⅰ) Temperature: 54 ℃

(Ii) Residence time: 120 minutes

(3) Melt tank of microcrystalline additives attached to crystal tower A (3)

(Ⅰ) Temperature: 55 ℃

(Ii) Residence time: 6 minutes

In the above experiment, the proportion of the particles having a particle size of 100 μm or less in the crystal adduct separated from the slurry obtained through the line 20 was 20% by weight.

Example B-3 (third process)

In Example B-2, the temperature of the crystallization tower A is changed to 44 ° C, and the difference between the temperature in the microcrystalline adduct dissolution tank 3 and the temperature of the crystallization tower A is set to 5 ° C. The experiment was performed similarly except having set the residence time of the slurry in the tank 3 to 4 minutes. As a result, the proportion of the particulate component having a particle size of 100 µm or less contained in the crystal additive in the slurry recovered through the line 20 was 29.5 wt%.

Comparative Example B-2

In Example B-3, the same experiment was conducted except that a part of the slurry extracted from the bottom of the inner cylinder 2 was not recycled through the heater 5 and the tank 3. As a result, the proportion of the particulate component contained in the crystal adduct in the slurry recovered through the line 20 was 69% by weight.

[Reference Example B-1 (Reference Example of Fifth Process)]

The reaction product obtained by making acetone and phenol react in presence of an acidic catalyst was concentrated, crystallized at 50 degreeC, and 3000 g of crystallization slurries of 20 wt% of bisphenol A phenol addition products were obtained. This was washed and filtered using 600 g of purified phenol prepared separately under reduced pressure filtration (prepared mother liquor (2250 g) obtained at this time as A) at 50 ° C (at this time, 580 g of the obtained washing liquid was B).

The crystalline adduct after washing was redissolved in 1310 g of purified phenol (APHA: 5) separately prepared, crystallized at 50 ° C, and a slurry of 20 wt% of bisphenol A-phenol adduct was obtained, which was filtered under reduced pressure at 50 ° C. After 1430 g of the obtained mother liquor was used as C), washing and filtration were performed twice with 600 g of purified phenol separately prepared (the first washing drainage 580 g obtained at this time was D and the second washing drainage 580 g was E). The impurity concentration of the bisphenol phenol crystal adduct thus obtained was 100 wt ppm, and the molten color was 5 APHA.

Example B-4 (Fifth Process)

In the same manner as in Reference Example B-1, the reaction product obtained by reacting acetone and phenol in the presence of an acid catalyst was concentrated and crystallized at a temperature of 50 ° C to obtain 3000 g of a crystallization slurry of bisphenol A and 20 wt% of a phenol crystal adduct. The crystal adduct obtained by filtering this under reduced pressure at 50 degreeC was wash | cleaned with 700 g of mother liquid C of the reference example B-1. The remaining 730 g of the mother liquor C of Reference Example B-1 and 580 g of the washing liquid D were added to the crystalline adduct after washing, and redissolved, and then crystallized at 50 ° C. It obtained and filtered under reduced pressure at 50 degreeC. Subsequently, the obtained crystal adduct was washed with washing liquid E580 of Reference Example B-1, and then washed with 600 g of purified phenol again as a final washing step. The impurity concentration of the obtained bisphenol A phenol crystal adduct was 100 wt ppm as in the reference example, and the melt color was 5APHA.

Therefore, in this Example, only the refined phenol was used for the washing | cleaning process of the last stage, and all the rest used the mother liquid or washing | cleaning liquid collect | recovered at the back-end side of a process, and the usage-amount of refined phenol is reduced, and high quality bisphenol is used. A-phenol crystal adduct, Furthermore, high quality bisphenol A can be obtained.

Example B-5 (Sixth Process)

In the reaction product obtained by making phenol and acetone react in presence of an acidic catalyst, after phenol was distilled off, the obtained concentrate was crystallized at 50 degreeC, and the crystalline adduct slurry containing 20 weight% of bisphenol A phenol crystalline adduct was obtained.

Next, the slurry was filtered under reduced pressure while maintaining the slurry temperature at 50 ° C. with a filter having a filter cloth having a 106 μm mesh, and then the obtained crystal addition product cake was washed with purified phenol.

The proportion of the microcrystalline adduct component of 100 µm or less in this washing crystal addition product was 5% by weight. The molten color of this crystal adduct was 10 APHA, and the concentration of colored impurities was remarkably low. In addition, the concentration of the chromman compound (coloring impurity) contained in this crystal adduct was 100 wt ppm.

Moreover, except having used the thing of the various mesh as a filter cloth in the above, the crystal addition product in which the microcrystal addition product content rate of 100 micrometers or less of particle diameters changed variously was obtained. About this crystal addition product, the density | concentration of the hue APHA of a molten color, and a Kroman compound is measured, and the result is shown to Table B-2.

As can be seen from the results shown in Table B-2, the crystal adduct having a support ratio of 20% by weight or less of the microcrystalline adduct component having a particle size of 100 μm or less is excellent in color and has a concentration of a chroman compound which is a complexing impurity. It is also of high quality.

[C: Preparation of Bisphenol A]

Example C-1 (First Process)

A mixture of bisphenol A, phenol and impurities, obtained by reacting phenol and acetone in the presence of an acid catalyst, was treated in a multistage crystallization process to obtain a crystal adduct of molten color APHA 5, pH 5.05.

Next, the crystal addition product was melted and heated using an external heat-sealed heating container under conditions of temperature: 130 ° C., pressure (absolute pressure): 1.20 atm, and oxygen concentration in the atmosphere: 0.0010 vol%. To a closed evaporator and evaporated at a melt temperature of 180 ° C. and an oxygen concentration of 0.001 vol% in the atmosphere, followed by introducing steam, and stripping at a temperature of 0.0030 wt% of oxygen in an atmosphere at a temperature of 180 ° C. Pinged.

The bisphenol A thus obtained had a purity of 99.96% by weight and a prephenol content of 30 wt ppm or less, and was of a high quality exhibiting the color of the molten color APHA 20.

Comparative Example C-1

In Example C-1, experiments were carried out in the same manner except that the oxygen concentration in the atmosphere in the heating and melting step of the crystal addition product and the evaporation and stripping treatment step of the melt were set to 0.006 vol%. In this case, the obtained bisphenol A exhibited a molten color APHA 65 and had a purity of 99.96% by weight or more and a prophenol content of 30 wt ppm or less.

Example C-2

In Example C-1, the experiment was carried out similarly except using the separately prepared melt APHA 10 and the pH of the crystal addition product of pH 4.85. In this case, the obtained bisphenol A showed the molten color APHA 40, and was 99.90 weight% or more of purity, and 50 ppm or less of prephenol content.

Comparative Example C-3

In Example C-1, the same experiment was conducted except that the separately prepared molten color APHA 20 and pH 5.05 adduct were used. Obtained bisphenol A showed the molten color APHA45, It was 99.96 weight% or more of purity, and was 30 wt ppm or less of prephenol content.

Example C-2

In Example C-1, the experiment was carried out in the same manner except that the oxygen concentration in the atmosphere in the heat melting step of the crystal addition product and the evaporation step of the melt were variously changed. The results are shown in Table C-1.

In addition, BPA in Table C-1 represents bisphenol A. Experiment No. 6 shows a comparative example.

Example C-3 (second process)

A mixture of bisphenol A phenol, which is a molten color 50 APHA, and impurities obtained by reacting phenol and acetone in the presence of an acid catalyst was crystallized in multiple steps to precipitate a crystal adduct. The slurry solution was filtered under reduced pressure to obtain a solid crystal adduct, and the resultant was washed with a purified phenol obtained by the method described later in a proportion of 2.5 parts by weight based on 1 part by weight of the adduct. The molten crystal obtained as described above (color: APHA 5 to 10, pH 5.05 or less) was melted under the condition of oxygen concentration in the atmosphere: 0.0010 vol%, and the obtained melt was then subjected to a temperature of 175 ° C, a pressure of 10 Torr, and an oxygen concentration in the atmosphere. : Evaporation was carried out under the condition of 0.0010 vol%, and phenol was substantially completely removed to obtain bisphenol A. In this case, the prephenol content was 30 wt ppm or less.

Next, the bisphenol A was heated and maintained at 175 ° C. for 0 hours or 2 hours in an air atmosphere, and air was blown at 175 ° C. for 2.0 hours to accelerate thermal stability test (test B). Evaluated the color at that time. The results are shown in Table C-2. In addition, experiment numbers 6-12 show a comparative example.

In addition, the refined phenol used above was a melt color 6 APHA, and commercially available phenol (water concentration 0.1 wt%, impurity concentration 0.05 wt%) using an Amberlite IR-118H + resin manufactured by Rohm and Haas Inc. It was obtained by contact treatment at a contact time of 50 minutes and by distillation at a distillation column bottom temperature of 175 ° C and a tower static pressure of 560 Torr.

Comparative Example C-4

In Example C-3, the same experiment was conducted except that the separately prepared molten color APHA 5 to 10 and pH 4.85 crystalline adduct were used. The color of Bisphenol A obtained in this case was as Table C-3. Moreover, the prephenol in bisphenol A was 50 wt ppm.

Comparative Example C-5

Bisphenol A was obtained in the same manner as in Example C-3 when the purified phenol was distilled off at a column bottom temperature of 200 ° C., but this showed a molten color APHA 30 after Test A of 175 ° C. to 0 hours.

Example C-4 (third process)

A mixture of bisphenol A, a phenol and an impurity of molten color 50 APHA, obtained by reacting phenol and acetone in the presence of an acid catalyst, was crystallized in multiple steps to obtain a crystal addition product (color: APHA 5 to 10, pH 4.85 or less). The additive shown in Table C-4 was added to the crystal addition product, and the resultant melt was melted under the conditions of temperature: 150 ° C and oxygen concentration in the atmosphere: 0.0010 vol%. By evaporation under conditions of a medium oxygen concentration of 0.0010 vol%, bisphenol A was obtained by substantially completely removing phenol. In this case, the prephenol content was 30 wt ppm or less.

Next, the thermal stability test (test A) which kept this bisphenol A for 0 hours at 175 degreeC and 2 hours at 175 degreeC under air atmosphere, and the accelerated thermal stability test (test B) which blows air at 175 degreeC for 2.5 hours were performed, The color at that time was evaluated. The results are shown in Table C-4. In addition, experiment numbers 6-9 show a comparative example.

In addition, in the additive shown in Table C-4, the additive amount according to the present invention (Experiment Nos. 1 to 5) is the neutralization equivalent amount of the strongly acidic substance in the crystal additive (about 1 ppm relative to the crystal additive), for comparison. The amount of the additive (Experiment Nos. 6 to 8) added was about 20 ppm relative to the crystal adduct.

Example C-5

In Example C-4, the same experiment was conducted except that the molten color APHA 5 to 10 and pH 4.22 crystal addition product were used. The results are shown in C-5.

In addition, in the additive shown in Table C-5, the addition amount of magnesium citrate and sodium malate according to the present invention is the neutralization equivalent amount of the strongly acidic substance in the crystal addition product (about 4 ppm relative to the crystal addition product), which was used for comparison. The addition amount of citric acid is 20 ppm with respect to a crystal addition product.

Example C-6 (fourth process)

As the melting apparatus, an external heating hermetic container made of SUS 304 was used, and a stripping apparatus made of SUS 304 was used as the evaporator. The crystal addition product supply pipe was provided in the upper part of the melter, and the melt pipe was provided in the bottom part, and this melt pipe was connected to the middle part of the stripping apparatus. In addition, a pipe for phenol vapor discharge was provided at the top of the stripping device, and a pipe for discharging the melt of bisphenol A was provided at the bottom thereof. In addition, all of the said piping was made of SUS304.

Next, in the apparatus system configured as described above, the liquid of the bisphenol A melt attached to the inner wall surface of the melting apparatus, the inner wall surface of the stripping apparatus, the piping between the melting apparatus and the stripping apparatus, and the stripping apparatus. The inner wall surface of the piping for discharging of was cleaned as follows.

(1) Cleaning the inner wall of the melting apparatus

After spraying the phenol liquid of 130 degreeC on an inner wall surface under normal pressure through a spray nozzle, and fully wash | cleaning an inner wall surface, it sprays 150 degreeC phenol / bisphenol A mixed liquid (mixed weight ratio: 65/35), and makes an inner wall surface Was sufficiently washed.

(2) Cleaning the inner wall of the stripping device

Under normal pressure, 130 ° C. phenol was allowed to flow through a spray nozzle attached to the upper part of the device, and after washing the center of the device, 130 ° C. phenol followed by 150 ° C. phenol / bisphenol A mixture (mixed weight ratio = 65/35 ) So that the device wall is sufficiently wetted. Subsequently, a phenol / bisphenol A mixture (mixed weight ratio = 65/35) was passed through under conditions of 180 ° C. and 10 Torr.

(3) Cleaning the inner wall of the pipe

The phenol at 130 ° C. was circulated through the pipe and washed. At that time, care was taken not to exist in the interior wall.

Moreover, it was confirmed that the amount of oxygen adhering to the inner wall surface of each apparatus and piping by said washing | cleaning was 5 millimoles or less per 1 m <2> of inner wall surfaces.

Next, using the apparatus in which the molten liquid of the crystal additive product and the molten liquid of bisphenol A contacted as described above, and the apparatus system in which the inner wall surface of the pipe was previously deoxygenated, the purified crystal additive product (molten colored APHA) was prepared as follows. Phenolic was removed by evaporation in 5), and bisphenol A was separated.

[Production of Crystal Additives]

A mixture of bisphenol A, a phenol and an impurity of melt color 50 APHA obtained by reacting phenol and acetone in the presence of an acid catalyst was crystallized to precipitate an adduct. This slurry solution was filtered under reduced pressure, and the refine | purified phenol obtained by the anti-friction mentioned later was wash | cleaned using 2.5 weight part with respect to 1 weight part of addition products, and the refined crystal addition product was obtained.

[Production of Purified Phenol]

The purified phenol used above was a thing of melt color 6 APHA, and was manufactured as follows. A commercial phenol (water concentration of 0.1 wt%, impurity concentration of 0.05 wt%) was subjected to contact treatment at a temperature of 80 DEG C and a contact time of 50 minutes using Amberlite IR-118H + resin manufactured by Rohm and Haas, and the resulting product was subjected to a distillation column. Distillation was carried out at a temperature of 175 ° C and a column top pressure of 560 Torr to recover purified phenol from the column.

[Operation Conditions]

Moreover, the operating conditions for the melting apparatus and the stripping apparatus in the above are as follows.

[Melting device]

Temperature: 130 ℃

Pressure: normal pressure

Atmospheric Oxygen Concentration: 0.0005vol%

[Striping device]

Temperature: 175 ℃

Pressure: 10 Torr

Atmospheric Oxygen Concentration: 0.0015vol%

Comparative Example C-6

In Example C-6, the same experiment was conducted except that the inner walls of the melting apparatus, the stripping apparatus, and the pipe were not cleaned.

Next, the molten color at 175 ° C of bisphenol A obtained in Example C-6 and Comparative Example C-6 is collectively displayed in the following table.

Example C-7 (Fifth Process)

An external heating hermetically sealed container made of SUS 316 was used as the crystal addition product dissolving device, and the inside was filled with a filler made of SUS 316.

Two packed towers made of SUS 304 were used.

In the melting apparatus, a crystal addition product supply pipe was placed thereon, a melt pipe was placed at the bottom thereof, and the pipe was connected to an intermediate portion of the first charging tower. In the first charging tower, pipes for phenol vapor discharge were laid at the top of the tower, a melt pipe containing bisphenol A and phenol was placed at the bottom thereof, and the pipes were connected to the middle of the second charging tower. The top of the second packed tower was provided with a pipe for discharging the mixed steam containing phenol, steam and a small amount of bisphenol A, which was connected to the cooling condenser shown in FIG. In addition, a bisphenol A discharge pipe and a steam supply pipe were installed at the bottom of the column of the second packed column.

Moreover, the heating coil which distribute | circulates a heating steam was arrange | positioned in each bottom part of said 1st charging tower and 2nd charging tower. In addition, all the above-mentioned pipings were all made of SUS316.

Next, in the apparatus system configured as described above, the inner wall surface of the melting apparatus, the inner wall surface of the first charging tower and the second charging tower and the filler surface thereof, piping between the melting apparatus and the first charging tower, The pipes between the first charging tower and the second charging tower and the bisphenol A discharge pipe disposed at the bottom of the second charging tower were washed as follows to remove the adhered oxygen.

(1) Cleaning the inner wall of the melting apparatus

After spraying 130 degreeC phenol liquid on the inner wall surface at normal pressure through a spray nozzle, and fully wash | cleaning an inner wall surface, it sprays 150 degreeC phenol / bisphenol A mixed liquid (mixed weight ratio = 65/35), and fully wash | cleans an inner wall surface. did.

Under normal pressure, 130 ° C. phenol was introduced through a spray nozzle installed at the top of the device, followed by washing in the device, followed by 130 ° C. phenol followed by 150 ° C. phenol / bisphenol A mixture (mixed weight ratio = 65/35). The device wall and the filler surface were circulated sufficiently to get wet. Subsequently, a phenol / bisphenol A mixture (mixed weight ratio = 65/36) was passed through under conditions of 180 ° C. and 10 Torr.

(3) Cleaning the inner wall of pipe

The phenol at 130 ° C was circulated through the pipe and washed. At that time, care was taken not to exist in the gas phase wall surface.

In addition, by the above cleaning, the amount of oxygen adhering to the inner wall surface of the melting apparatus, the inner wall surface of the packed column and its filler, and the inner wall surface of the pipe was found to be 5 mmol or less per 1 m 2 of surface area.

Next, using the above-described apparatus system in which the surface of the melting apparatus, the packed column, the filler, and the pipe which the molten liquid of the crystal additive adduct and the melt of bisphenol A are in contact with each other is previously deoxygenated, Phenolic was evaporated and removed by color APHA: 5), and the bisphenol A was separated and recovered, and cooling condensation treatment of the mixed vapor obtained in the top of the second packed column was performed.

[Production of Crystal Additives]

A mixture of bisphenol A, a phenol and an impurity, which is a molten color 50 APHA, obtained by reacting phenol and acetone in the presence of an acid catalyst was crystallized to precipitate a crystal adduct. The slurry solution was filtered under reduced pressure to obtain a solid crystal adduct. The purified phenol obtained by the method described later was washed at a ratio of 2.5 parts by weight based on 1 part by weight of the adduct, thereby obtaining a purified crystal adduct.

[Production of Purified Phenol]

The refined phenol used above was that of molten color 6 APHA and was produced as follows. A commercial phenol (water concentration of 0.1 wt%, impurity concentration of 0.05 wt%) was subjected to contact treatment at a temperature of 80 ° C. and a contact time of 50 minutes using Amberlite IR-118H + resin manufactured by Rohm and Haas, and the resulting product was subjected to a distillation column. Distillation was carried out at a temperature of 175 deg.

[Operation Conditions]

The operating conditions of the melting apparatus, the first charging tower, the second charging tower, and the cooling condensing system in the above are as follows.

[Melting device]

Temperature: 130 ℃

Pressure: normal pressure

Oxygen concentration in the atmosphere: 0.0005 vol%

[First charging tower]

Temperature: 170 ℃

Pressure: 10 Torr

Oxygen concentration in steam atmosphere: 0.0015 vol%

[Second charging tower]

Temperature: 180 ℃

Pressure: 10 Torr

Steam supply: 0.08㎏ per kg of melt

Oxygen concentration in steam atmosphere: 0.0005 vol%

[Operation conditions of the first cooler of FIG. 6]

(1) Stripping gas introduced into the first cooler 1 in the line 3

Pressure: 10 Torr

Temperature: 180 ℃

Composition: Bisphenol A 25 wt%, Phenol 25wt%, Steam 50 wt%

(2) a first cooling medium (phenol) introduced in line (5)

Temperature: 50 ℃

Cooling medium stripping gas weight ratio: 6

(3) Recovery rate of bisphenol A from the stripping gas in the cooler (1): 100%

[Operation conditions of the second cooler of FIG. 6]

(1) uncondensed gas introduced into the second cooler in line 8

Pressure: 10 Torr

Temperature: 51 ℃

Composition: Phenolic 65 wt%, Vapor 35 wt%

(2) Second cooling medium (phenol aqueous solution) introduced into the second cooler (2) in the line (9)

Temperature: 9 ℃

Cooling medium / uncondensed gas weight ratio: 190

(3) Recovery rate of each phenol and steam from uncondensed gas in the cooler (2)

Phenol Recovery Rate: 100%

Steam recovery rate: 100%

Example C-8

In Example C-7, the same experiment was conducted except that the oxygen removal treatment was performed only on the inner wall surface of each packed tower and the surface of the filler.

Comparative Example C-7

In Example C-7, the same experiment was conducted except that no oxygen removal treatment was performed.

Comparative Example C-8

In Example C-7, experiments were carried out in the same manner as in the case of using the packed column without oxygen removal treatment on the inner wall surface and the filler surface of each packed tower.

The molten color at 175 ° C of bisphenol A obtained in each of the above Examples and Comparative Examples is collectively shown in the following table.

Example C-9 (sixth process)

The reaction mixture obtained by reacting phenol and acetone in the presence of an acid catalyst was subjected to multistage crystallization. Bisphenol A-phenol crystalline adduct whose melt color was APHA 5 was partially diluted with purified phenol, and heated to 130 ° C. to give 30 weight of bisphenol A. It was set as the phenol solution containing%.

This phenol solution was used as a raw material liquid and processed using the evaporator system shown in FIG.

Next, the main operating conditions of the system shown in FIG. 6 and the composition of the liquid passing through the main line are shown below.

(1) Evaporator (1)

(Ⅰ) External heater temperature: 170 ℃

(Ii) Internal pressure: 20 Torr

(2) second evaporator (2)

(Ⅰ) External heater temperature: 180 ℃

(Ii) Internal pressure: 10 Torr

(3) Third Evaporator (3)

(Ⅰ) External heater temperature: 180 ℃

(Ii) Internal pressure: 10 Torr

(4) in bisphenol A passing through line 12

Phenol content; 2.7 wt%

(5) bisphenol A passing through line 16

(Iii) Phenol content: 23wt ppm

(Ii) Melt color: APHA 20

(6) Steam feed through line 15: 0.04 parts by weight per 1 part by weight of bisphenol A through line 14

Comparative Example C-9

When the operating conditions of the first evaporator 1 were 190 ° C. and 10 Torr, the phenol content in bisphenol A passing through the line 12 was reduced by only 7% by weight, and the operation of the first evaporator was unstable.

Comparative Example C-10

When the temperature of each external heater in the second evaporator 2 and the third evaporator 3 was set to 200 ° C., the molten color of the product bisphenol A passing through the line 16 was APHA 45 and the phenol content was 70 ppm. .

Example C-10 (seventh process)

The reaction mixture obtained by reacting phenol and acetone in the presence of an acid catalyst under substantially neutral conditions (pH 5.05) obtained by multi-stage crystallization, and partially diluting bisphenol A-phenol crystalline adduct having a melting color of APHA 5 with purified phenol. It heated to 130 degreeC and made it the phenol solution containing 30 weight% of bisphenol A.

This phenol solution was used as raw material liquid, and it processed using the evaporator system shown in FIG.

Next, the main operating conditions of the system shown in FIG. 6 and the composition of the liquid passing through the main line are shown below.

(1) Evaporator (1)

(Ⅰ) External heater temperature: 170 ℃

(Ii) Internal pressure: 20 Torr

(Iii) Oxygen concentration in the atmosphere: 0.0010 vol%

(2) second evaporator (2)

(Ⅰ) External heater temperature: 180 ℃

(Ii) Internal pressure: 10 Torr

(Iii) Oxygen concentration in the atmosphere: 0.0030 vol%

(3) Third Evaporator (3)

(Ⅰ) External heater temperature: 180 ℃

(Ii) Internal pressure: 10 Torr

(Iii) Oxygen concentration in the atmosphere: 0.0030 vol%

(4) bisphenol A passing through line 16

(Iii) Phenol content: 29 wt ppm

(Ii) Melt color: APHA 15

(5) the amount of steam supplied through line 15; 0.04 part by weight relative to 1 part by weight of bisphenol A across line 14

Example C-11

In Example C-10, the same experiment was conducted except that 20 wt ppm of the additive shown in Table 8 was added to the phenol solution containing bisphenol A as a raw material. By this experiment, high purity bisphenol A (APHA: 10, phenol content: 27 wt ppm) was obtained through line 16.

Next, using the thermal stability test (test A) which keeps this bisphenol A heated at 175 degreeC for 0 hours or 2 hours in air atmosphere, and the accelerated thermal stability test (test B) which blows air at 175 degreeC for 2.0 hours, The color of was evaluated. The results are shown in Table C-8.

Example C-12

A mixture of bisphenol A, a phenol and an impurity, which is a molten color 50 APHA obtained by reacting phenol and acetone in the presence of an acid catalyst, was crystallized in multiple steps to precipitate a crystal adduct. The slurry solution was filtered under reduced pressure to obtain a solid crystal adduct. The purified phenol obtained by the method described below was washed at a ratio of 2.5 parts by weight with respect to 1 part by weight of the adduct, and then the crystal adduct (color: APHA 5 to 10). , pH 5.05 or less).

Next, 1 part by weight of purified phenol was added to 1 part by weight of the crystal adduct, and the resultant melt (pH 5.05) was evaporated in the same manner as in Example C-1 to obtain high-purity bisphenol A (purity: 99.96 wt%). ) The phenol content of this bisphenol A was 30 wt ppm or less, and the melt color was 15 APHA. In addition, the refined phenol used above was of melt color 6 APHA, and commercially available industrial phenol (water concentration of 0.1 wt%, impurity concentration of 0.05 wt%) was contacted with a temperature of 80 ° C. using Amberlite IR-118H + resin manufactured by Rohm and Haas The resultant was subjected to contact treatment at a time of 50 minutes, and distilled at a distillation column temperature of 175 ° C and a tower static pressure of 560 Torr.

Example C-13

Continuous condensation of the stripping gas was carried out according to the system diagram shown in FIG. The operating conditions of the first cooler 1 and the second cooler 2 in this case are shown below.

[Operation conditions of the first cooler]

(1) Stripping gas introduced into the first cooler 21 from the line 23

Pressure: 10 Torr

Temperature: 180 ℃

Composition: Bisphenol A 25 wt%, Phenol 25wt%, Steam 50wt%

(2) First cooling medium (phenol) introduced from line 25

Temperature: 50 ℃

Cooling medium / stripping gas weight ratio: 6

(3) Recovery rate of bisphenol A from the stripping gas in the cooler 21: 100%

[Operation conditions of the second cooler]

(1) uncondensed gas introduced into the second cooler 22 from the line 28

Pressure: 10 Torr

Temperature: 51 ℃

Composition: Phenolic 65wt%, Vapor 35wt%

(2) Second cooling medium (phenol aqueous solution) introduced into the second cooler 22 from the line 29

Temperature: 9 ℃

Cooling medium / uncondensed gas weight ratio: 190

(3) Recovery rate of each of phenol and steam from uncondensed gas in the cooler 21

Phenol Recovery: 100%

Steam recovery rate: 100%

Claims (6)

In obtaining the bisphenol A by evaporating and removing phenol from bisphenol A phenol crystal adduct, the phenol solution containing bisphenol A formed from this crystal adduct is made into a temperature of 160-185 degreeC, and 15-15 using a thin film evaporator. A phenol evaporation step of evaporating under a pressure of 60 Torr to obtain a bisphenol A having a phenol content of 1 to 5% by weight, and a bisphenol A containing phenol obtained in this phenol evaporation step at a temperature of 170 to 185 ° C and 15 Torr or less. The first stripping step of stripping treatment by countercurrently contacting the stripping gas at a pressure of and bisphenol A containing phenol obtained in the first stripping step was carried out at a temperature of 170 to 185 ° C and a pressure of 15 torr or less. It consists of a 2nd stripping process of carrying out a stripping process by making it countercurrently contact with the stripping gas, and uses steam as a stripping gas in this 2nd stripping process. And a stripping gas composed of steam containing phenol and bisphenol A obtained in the second stripping step as a stripping gas in the first stripping step. . The method according to claim 1, wherein the molten color of the bisphenol A-phenol crystal adduct is 15 APHA or less. A phenol solution containing bisphenol A, which is substantially neutral, and formed of bisphenol A-phenol crystalline adduct having a melt color of 15 APHA or less, was subjected to a thin film evaporator using a thin film evaporator in a range of 160 to not more than 0.005% by volume of oxygen in the atmosphere. The phenol evaporation process which obtains bisphenol A whose phenol content is 1-5 weight% by evaporating under the temperature of 185 degreeC and the pressure of 15-60 torr, and the bisphenol A containing the phenol obtained by this phenol evaporation process are 170-185 degreeC And a bisphenol A containing a phenol obtained in the first stripping process and the phenol obtained in the first stripping process by stripping the stripping process by countercurrently contacting the stripping gas under a temperature of 15 Torr and a pressure of 15 torr. It consists of the 2nd stripping process of carrying out a stripping process by carrying out countercurrent contact with the stripping gas under the following pressures, The stripping process in this 2nd stripping process A steam is used as the gas for tripping, and a stripping gas composed of vapors containing phenol and bisphenol A obtained in the second stripping step is used as the stripping gas in the first stripping step. Process for the preparation of high quality bisphenol A. The method according to claim 3, wherein the phenol is removed after the aliphatic carboxylic acid is added and mixed with the phenol solution containing bisphenol A formed from bisphenol A phenol crystal adduct. 4. The process according to claim 3, wherein the bisphenol A.phenol crystalline adduct is washed with purified phenol after re-dissolving and rearranging at least once. The method of claim 1, wherein the stripping gas containing phenolic compound, bisphenol A and steam discharged from the first stripping process is maintained as a gas under low pressure conditions of 30 Torr or less, and a portion of the phenolic compound is converted into a liquid. Under refrigerated contact with a first cooling medium comprising phenol or phenol containing bisphenol A, condensing substantially the entire amount of bisphenol A contained in the stripping gas and a portion of the phenol, while uncondensing steam After obtaining a mixed gas of phenol and the phenol, the mixed gas is then brought in countercurrent contact with a second cooling medium consisting of an aqueous solution of phenol under low pressure conditions of 30 Torr or less and under temperature conditions to condense substantially the entire amount of the mixed gas, And condensing substantially the entire amount of the mixed gas.