JP2011132160A - Method of producing aliphatic polyisocyanate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of producing an aliphatic polyisocyanate employing a hydrochloride method and capable of shortening the operation time in its production process to improve its productivity. <P>SOLUTION: The method of producing an aliphatic polyisocyanate comprising a first reaction process of allowing an aliphatic polyamine to react with hydrogen chloride in a first reaction tank 10 in the presence of an inert organic solvent, subsequently allowing the reaction product to react with phosgene, and keeping the resulting reaction liquid at a specified temperature, a second reaction process of keeping the reaction liquid produced in the first reaction process in a second reaction tank 11 at a specified temperature, and a separation process of separating aliphatic polyisocyanate from the reaction liquid produced in the second reaction process, with the first reaction process employing a plurality of first reaction tanks 10, is characterized by starting, while a first reaction process is in progress in one of the first reaction tanks 10, another first reaction process in another of the first reaction tanks 10, and feeding the reaction liquid alternately from the plurality of first reaction tanks 10 to the second reaction tank 11. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing an aliphatic polyisocyanate.

  Isocyanates used as a raw material for urethane resins are generally produced by reacting a raw material polyamine with phosgene (phosgenation reaction) (see, for example, Patent Document 1).

  The phosgenation reaction includes a method in which a raw material polyamine and phosgene are directly reacted (direct method), and a method in which the raw material polyamine is once reacted with hydrogen chloride to form an amine hydrochloride, which is then reacted with phosgene (hydrochloride method). ) Is known.

  Among them, the hydrochloride method is known to have an advantage that the production of by-products can be suppressed as compared with the direct method. Therefore, among isocyanates, in particular, aliphatic polyisocyanates such as hexamethylene diisocyanate (HDI) are generally produced using a hydrochloride method (see, for example, Patent Document 2).

Japanese translation of PCT publication No. 2006-510692 (paragraph 0004) Japanese Patent Publication No. 6-8269

  However, the hydrochloride method is advantageous as compared with the direct method from the viewpoint of suppression of by-products as described above, but the raw material polyamine must be reacted with hydrogen chloride before the reaction with phosgene. Since the operation procedure is complicated and the manufacturing process takes time, and the batch method must be employed to hold the reaction solution in the reaction tank for a certain period of time, the productivity is low.

  An object of the present invention is to shorten the time of the production process and improve productivity in the production method of aliphatic polyisocyanate using the hydrochloride method.

The method for producing an aliphatic polyisocyanate according to the present invention is a method for producing an aliphatic polyisocyanate by reacting an aliphatic polyamine with phosgene in the presence of an inert organic solvent.
A first reaction step in which an aliphatic polyamine is reacted with hydrogen chloride in the presence of an inert organic solvent in the first reaction tank, then reacted with phosgene, and the reaction solution is maintained at a predetermined temperature; and the first reaction step. The reaction solution obtained in step 2 is a second reaction step for holding the reaction solution at a predetermined temperature in a second reaction tank, and a separation step for separating the aliphatic polyisocyanate from the reaction solution obtained in the second reaction step. Including
In the first reaction step, a plurality of independent first reaction vessels are used, and the first reaction step is performed in another first reaction vessel during the progress of the first reaction step in a certain first reaction vessel. The reaction solution is started and the reaction solution is alternately supplied from the plurality of first reaction vessels to the second reaction vessel.

  In the present invention, first, an aliphatic polyamine is reacted with hydrogen chloride to form an amine hydrochloride in the first reaction tank, and then reacted with phosgene to hold the reaction solution at a predetermined temperature (first reaction step). . Next, the reaction liquid obtained in the first reaction step is supplied to the second reaction tank, and the reaction liquid is held at a predetermined temperature in the second reaction tank (second reaction step). And aliphatic polyisocyanate is isolate | separated from the reaction liquid obtained at the 2nd reaction process (separation process).

  Here, in the first reaction step, a plurality of independent first reaction vessels are used, and the first reaction step is started in another first reaction vessel during the progress of the first reaction step in a certain first reaction vessel. To do. Then, the reaction solution is alternately supplied from the plurality of first reaction vessels to the second reaction vessel. In this way, the production time of the aliphatic polyisocyanate can be greatly shortened by allowing the reactions to proceed simultaneously in the plurality of first reaction vessels.

  Further, in the method for producing an aliphatic polyisocyanate according to the present invention, in the second reaction step, a plurality of the second reaction tanks arranged in series are used, and the second reaction tank on the downstream side from the second reaction tank on the upstream side is used. It is preferable to keep the reaction liquid at a predetermined temperature in each of the plurality of second reaction tanks while sequentially transferring the reaction liquid to the two reaction tanks.

  According to the present invention, the first reaction step is performed in parallel using a plurality of first reaction tanks, and the reaction liquid is alternately supplied from the plurality of first reaction tanks to the second reaction tank. The production time of the aliphatic polyisocyanate employing the salt method can be greatly shortened and the productivity can be improved.

It is a figure which shows roughly the manufacturing process of the aliphatic polyisocyanate which concerns on this embodiment. It is a figure which shows schematically the manufacturing process of HDI in an Example and a comparative example. It is a time chart of an Example and a comparative example. 3 is a chart showing details of all steps of Example 1. FIG. 5 is a chart showing details of all steps of Comparative Example 1; It is a chart which shows all the processes of comparative example 2 in detail.

  Next, preferred embodiments of the present invention will be described in detail. In this embodiment, an aliphatic polyisocyanate is produced using a hydrochloride method. First, an aliphatic polyamine as a raw material is reacted with hydrogen chloride to produce an amine hydrochloride (salt formation reaction), then, a reaction solution containing this amine hydrochloride is reacted with phosgene (phosgenation reaction), and the temperature is set to a predetermined temperature. Hold to produce an aliphatic polyisocyanate. Then, aliphatic polyisocyanate is isolate | separated from the obtained reaction liquid (separation process).

  Examples of the aliphatic polyisocyanate in the present invention include aliphatic diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, 3-methyl-1,5-pentane diisocyanate, and lysine diisocyanate, isophorone diisocyanate, hydrogenated tolylene diisocyanate, and hydrogenated xylene diisocyanate. And alicyclic diisocyanates such as hydrogenated diphenylmethane diisocyanate and tetramethylxylene diisocyanate.

(Salt making reaction)
The salt formation reaction is performed by reacting an aliphatic polyamine with hydrogen chloride in the presence of an inert organic solvent in a reaction vessel. The method of reacting the aliphatic polyamine and hydrogen chloride is not particularly limited. For example, a method in which a solvent in which a polyamine is dissolved is dropped into an organic solvent in a reaction tank, and hydrogen chloride gas is charged. A method of dropping the amine solution after the hydrogen chloride gas is absorbed in the organic solvent in the tank, or a method of charging the hydrogen chloride gas into the amine solution in the reaction tank can be employed. Inert organic solvents that can be used include aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as chlorotoluene, chlorobenzene, dichlorobenzene, orthodichlorobenzene, and trichlorobenzene, and esters such as butyl acetate and amyl acetate. And ketones such as methyl isobutyl ketone.

(Phosgenation reaction)
The phosgenation reaction is carried out by further introducing phosgene after the salt formation reaction and holding the reaction solution at a predetermined temperature for a certain time. The reaction (retention) temperature at this time is preferably 100 to 180 ° C. The reaction pressure is preferably 0.1 to 1 MPa. When the reaction pressure is higher, the phosgenation reaction proceeds more rapidly, but when it is higher than 1 MPa, the safety of the apparatus may be a problem.

(Separation process)
The reaction solution after the phosgenation reaction is a mixture of aliphatic polyisocyanate and residual phosgene, hydrogen chloride, an inert organic solvent, or the like. Therefore, this reaction solution is transferred to a separator to separate the aliphatic polyisocyanate. As a separation method, distillation separation using a distiller is preferable. Separation by a distiller may be atmospheric distillation or vacuum distillation, but vacuum distillation is preferred because distillation is preferably performed at as low a temperature as possible.

  Thus, in the production of aliphatic polyisocyanates, when the hydrochloride method in which polyamine and hydrogen chloride are first reacted before the reaction with phosgene is adopted, the secondary method is compared with the direct method in which polyamine is directly reacted with phosgene. Since the production of organisms is suppressed, the yield is increased. However, since the production time becomes longer as described above, an aliphatic polyisocyanate is produced by the following steps in order to shorten the production time.

  FIG. 1 is a diagram schematically showing a production process of an aliphatic polyisocyanate according to this embodiment. As shown in FIG. 1A, an aliphatic polyamine and hydrogen chloride (HCl) are introduced into the first reaction tank 10 to perform a salt formation reaction, and then phosgene (CC) is introduced to start a phosgenation reaction. Then, the reaction solution is held at a predetermined temperature for a certain time in the first reaction tank 10 (first reaction step). Next, the reaction liquid is transferred to the second reaction tank 11, and the reaction liquid is held at 100 to 180 ° C. for a certain time (until the phosgenation reaction is completed) in the second reaction tank 11 (second reaction step). . If it is less than 100 ° C., the reaction proceeds slowly. Moreover, when higher than 180 degreeC, a by-product produces | generates and the problem that a yield falls may arise. Thereafter, the aliphatic polyisocyanate is distilled and separated from the reaction solution in the distiller 12.

  Here, as shown to Fig.1 (a), two 1st reaction tanks 10 (10A, 10B) which perform a 1st reaction process are used. Two independent first reaction tanks 10 are arranged in parallel, and in the middle of the first reaction step (salt formation reaction and phosgenation reaction) in one first reaction tank 10, another first reaction tank 10 start the first reaction step. Then, the reaction solution is supplied from the first reaction tank 10 to the second reaction tank 11 after the first reaction step is completed (a certain time has elapsed from the start of the reaction). 11 to supply the reaction solution alternately. Thus, by using two first reaction tanks 10 together and allowing the reactions to proceed simultaneously in the two first reaction tanks 10, the manufacturing time can be greatly shortened.

  In addition, the number of the 1st reaction tank 10 is not restricted to two, You may arrange | position and use the 3 or more 1st reaction tank 10 in parallel.

  Further, as shown in FIG. 1B, in the second reaction step, two or more second reaction tanks (11A, 11B) may be used. In this case, while sequentially transferring the reaction liquid obtained in the first reaction step from the second reaction tank (11A) on the upstream side to the second reaction tank (11B) on the downstream side, In each, the reaction solution is held at a predetermined temperature. If the number of the second reaction tank 11 is one, the reaction liquid cannot be received from the first reaction tank 10 until the reaction liquid in the second reaction tank 11 is transferred to the distiller 12. If the second reaction tanks 11 are arranged in series and sequentially transferred while holding the reaction liquid for a certain period of time, the reaction proceeds by holding the reaction liquid in the second reaction tank 11 on the downstream side. During the reaction, the reaction liquid can be received from the first reaction tank 10 in another second reaction tank 11. That is, the holding of the reaction liquid in the plurality of second reaction tanks 11 (that is, the progress of the phosgenation reaction) can be performed in parallel, and the manufacturing time can be further shortened.

  Next, the present invention will be described in more detail with reference to examples. However, the present invention is not construed as being limited in any way by the following examples. In the following description, “%” represents “mass%” unless otherwise specified.

  The aliphatic polyisocyanate produced in the examples and comparative examples was hexamethylene diisocyanate (HDI). HDI is obtained by reacting hexamethylenediamine (HDA) with phosgene.

<Details of analysis items>
The HDI solution obtained by the reaction between HDA and phosgene was analyzed by gas chromatography (GC).
HDI peak area area ÷ total peak area area × 100 (PA%)
The purity (PA%) of HDI was calculated using the following formula.

<Synthesis of HDI>
FIG. 2 schematically shows the steps of Example 1 and Comparative Examples 1 and 2. FIG. 3 is a time chart of Example 1 and Comparative Examples 1 and 2.

Example 1
As shown in FIG. 2, in Example 1, the first reaction steps (the first half of the salt formation reaction and the phosgenation reaction) were performed using the two first reaction vessels A and B, respectively. In addition, the second reaction step (second half of the phosgenation reaction) was performed using two second reaction vessels A and B arranged in series. That is, the reaction solution is alternately supplied from the two first reaction vessels A and B to the second reaction vessel A, and the reaction solution is held in the second reaction vessel A for a predetermined time, and then transferred to the second reaction vessel B. In the second reaction tank B, the reaction solution was held for a predetermined time. Then, the separation process which transfers the reaction liquid of the 2nd reaction tank B to a distiller, and isolate | separates HDI was performed.
Also, one batch of treatment in the first reaction tanks A and B (first reaction process), treatment in the second reaction tanks A and B (second reaction process), and treatment in the still (separation process). As a result, a total of 4 batches were continuously performed. In FIG. 4, the detail of all the processes of Example 1 is shown.

[First reaction step]
Each of the first reaction tanks A and B is an apparatus having an internal volume of 500 ml equipped with a thermometer, a hydrogen chloride gas blowing tube, a raw material dropping device, a cooling reflux tower, and a stirrer.
As FIG. 4 shows, the 1st reaction process performed with a 1st reaction tank consists of the following processes 1) -5).
1) The first reaction tank was charged with 150 g of orthodichlorobenzene (ODCB) that had been heated to 120 ° C. in advance.
2) 55 g of ODCB solution containing 20.5 g of HDA was added to the first reaction tank over 40 minutes with hydrogen chloride gas 0.5 g / min while stirring at 200 rpm.
3) While maintaining the mixed solution at 170 ° C., 160 g of ODCB solution containing 105 g of phosgene (CC) was added over 10 minutes.
4) The reaction was allowed to proceed for 95 minutes, and then the reaction solution was transferred to the second reaction tank A.
5) The first reaction vessel was washed with ODCB.
FIG. 4 shows the required time and accumulated time of each step 1) to 5), and the time required to perform the steps 1) to 5) in one batch is 160 minutes. .

[Second reaction step]
The second reaction tanks A and B are apparatuses having the same shape as the first reaction tank, and their internal volumes are also the same.
In the 2nd reaction tank A, the reaction liquid supplied from the 1st reaction tank was made to react for 75 minutes, hold | maintaining at 170 degreeC, and the reaction liquid was transferred to the 2nd reaction tank B after that. In the 2nd reaction tank B, the reaction liquid supplied from the 2nd reaction tank A was made to react for 75 minutes, hold | maintaining at 170 degreeC similarly to the 2nd reaction tank A, Then, the reaction liquid was transferred to the distiller. Note that this second reaction step starts immediately after completion of liquid transfer from the first reaction tank (after completion of step 4 described above). That is, as shown in FIG. 4, if it is the first batch, it starts after 150 minutes have passed since the completion of step 4). The time required for the second reaction step is 80 minutes including the time required for the liquid transfer in each of the second reaction tanks A and B. Therefore, if it is the first batch, the elapsed (integrated) time from the start of production at the stage where the second reaction step is completed is 150 + 80 (second reaction tank A) +80 (second reaction tank B) = 310 minutes. .

[Separation process]
In the distiller, the reaction solution supplied from the second reaction tank B is distilled for 90 minutes under reduced pressure, CC and ODCB are removed, and HDI is taken out. Since this separation process is performed immediately after the liquid transfer from the second reaction tank B, for example, in the case of the first batch, as shown in FIG. The (integrated) time is 310 + 90 = 400 minutes.

  The time chart of Example 1 is shown to Fig.3 (a). In addition, (1)-(4) of FIG. 3 has shown by which batch it is a process. In Example 1, two first reaction vessels A and B are used, and the reaction of the next batch in the other first reaction vessel is started while the reaction in one first reaction vessel is in progress. . Specifically, as shown in FIG. 4, in the middle of the first reaction step (after 80 minutes from the start of each batch) after moving to step 4) in one first reaction tank, the other Start the next batch step 1) in the first reactor.

(Comparative Example 1)
As shown in FIG. 2, in Comparative Example 1, a separation step in which the salt formation reaction and the phosgenation reaction are performed to the end in one first reaction tank, and then the reaction solution is supplied to a distiller to separate HDI. went.
And the process in a 1st reaction tank and the process in a distiller were made into 1 batch, and a total of 4 batches were performed. FIG. 5 shows details of all the steps of Comparative Example 1. Moreover, the time chart of the comparative example 1 is shown in FIG.3 (b).

  The first reaction step (step 1) to step 5)) in FIG. 5 are substantially the same as those in Examples 1 and 2, but in the step 4) in which the phosgenation reaction is performed because the second reaction tank is not used. The time is as long as 258 minutes.

(Comparative Example 2)
As shown in FIG. 2, in Comparative Example 2, the first reaction step (the first half of the salt formation reaction and the phosgenation reaction) was performed in one first reaction tank. In addition, the second reaction step (second half of the phosgenation reaction) was performed using two second reaction vessels A and B arranged in series. Then, the separation process which transfers the reaction liquid of the 2nd reaction tank B to a distiller, and isolate | separates MDI was performed.
Then, the treatment in the first reaction tank (first reaction process), the treatment in the second reaction tanks A and B (second reaction process), and the treatment in the distiller (separation process) are considered as one batch. Four batches were performed in succession. FIG. 6 shows details of all the steps of Comparative Example 2. Moreover, the time chart of the comparative example 2 is shown in FIG.3 (c). The contents of the individual steps of the first reaction step (step 1) to step 5)), the second reaction step, and the separation step in FIG. 6 are the same as those in the first embodiment.

  Table 1 shows a summary of implementation conditions and results for each of Example 1 and Comparative Examples 1 and 2 described above.

  In Table 1, the productivity index represents a value obtained by dividing the total MDI yield (g) of the four batches by the end time (minutes) of the fourth batch. A higher productivity index indicates higher productivity.

<Verification>
The yield and purity of HDI are the same in Example 1 and Comparative Examples 1 and 2. This is a natural result because Example 1 and Comparative Examples 1 and 2 all employ the hydrochloride method. However, there was a difference in the productivity index.

  The productivity index (0.185) of Example 1 is considerably higher than those of Comparative Example 1 (0.087) and Comparative Example 2 (0.135). As can be seen from FIG. 3, in Example 1 in which two first reaction vessels are used, the first reaction steps of the preceding and following batches proceed in parallel between the two first reaction vessels. This is because the entire manufacturing time is shortened.

10 1st reaction tank 11 2nd reaction tank 12 Distiller

Claims (2)

In a process for producing an aliphatic polyisocyanate by reacting an aliphatic polyamine with phosgene in the presence of an inert organic solvent,
A first reaction step in which an aliphatic polyamine is reacted with hydrogen chloride in the presence of an inert organic solvent in a first reaction tank and then reacted with phosgene, and the reaction solution is maintained at a predetermined temperature;
A second reaction step in which the reaction solution obtained in the first reaction step is held in a second reaction tank at a predetermined temperature;
A separation step of separating the aliphatic polyisocyanate from the reaction liquid obtained in the second reaction step,
In the first reaction step, a plurality of independent first reaction vessels are used,
During the progress of the first reaction step in a certain first reaction tank, the first reaction step is started in another first reaction tank,
A method for producing an aliphatic polyisocyanate, characterized in that a reaction solution is alternately supplied from the plurality of first reaction vessels to the second reaction vessel. In the second reaction step, using a plurality of the second reaction tanks arranged in series,
The reaction liquid is held at a predetermined temperature in each of the plurality of second reaction tanks while sequentially transferring the reaction liquid from the second reaction tank on the upstream side to the second reaction tank on the downstream side. The manufacturing method of aliphatic polyisocyanate as described in any one of.

Images