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WO1999020593A1 - Procede de preparation d'acide (meth)acrylique - Google Patents

Procede de preparation d'acide (meth)acrylique Download PDF

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Publication number
WO1999020593A1
WO1999020593A1 PCT/EP1998/006460 EP9806460W WO9920593A1 WO 1999020593 A1 WO1999020593 A1 WO 1999020593A1 EP 9806460 W EP9806460 W EP 9806460W WO 9920593 A1 WO9920593 A1 WO 9920593A1
Authority
WO
WIPO (PCT)
Prior art keywords
column
acrylic acid
meth
mixture
solvent
Prior art date
Application number
PCT/EP1998/006460
Other languages
German (de)
English (en)
Inventor
Holger Herbst
Gerhard Nestler
Ulrich Hammon
Albrecht Dams
Original Assignee
Basf Aktiengesellschaft
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Basf Aktiengesellschaft filed Critical Basf Aktiengesellschaft
Publication of WO1999020593A1 publication Critical patent/WO1999020593A1/fr

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/42—Separation; Purification; Stabilisation; Use of additives
    • C07C51/43—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation
    • C07C51/44—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation by distillation

Definitions

  • the invention relates to a process for the preparation of (meth) acrylic acid from a mixture which contains (meth) acrylic acid and a solvent with a boiling point above the boiling point of (meth) acrylic acid.
  • (Meth) acrylic acid is used as an abbreviation and stands for acrylic acid or methacrylic acid.
  • (Meth) acrylic acid, either as an acid or in the form of its ester, is particularly useful in the preparation of polymers for a wide variety of applications, e.g. as adhesives, textile auxiliaries or aqueous paint dispersions, of importance.
  • (Meth) acrylic acid is usually produced by catalytic gas phase oxidation of alkanes, alkanols, alkenes or alkenals which contain 3 or 4 carbon atoms.
  • (Meth) acrylic acid e.g. obtainable by catalytic gas phase oxidation of propene, acrolein, tert-butanol, isobutene or methacrolein.
  • These starting materials are gaseous, usually diluted with inert gases such as nitrogen, CO 2 , saturated hydrocarbons and / or water vapor, passed in a mixture with oxygen at elevated temperatures (usually 200 to 400 ° C) and, if appropriate, elevated pressure over mixed oxide catalysts and oxidatively converted to the (meth) acrylic acid.
  • inert gases such as nitrogen, CO 2 , saturated hydrocarbons and / or water vapor
  • the reaction mixture obtained in the oxidation of propene contains, among other things, acetic acid, propionic acid, maleic anhydride, aldehydes, propane, water, carbon oxides, nitrogen and oxygen.
  • the separation of the (meth) acrylic acid from the reaction mixture is carried out essentially by leading the reaction gases in a conventional absorption column to a descending absorbent in countercurrent, then in a desorption column consisting essentially of (meth) acrylic acid, the absorbent and secondary components
  • Composite liquid drain of the absorption column largely removed the volatile secondary components by stripping and then separates the liquid drain of the desorption column for the separation of the (meth) acrylic acid and low-volatile secondary components in a column by distillation.
  • the (meth) acrylic acid is usually separated off by feeding the mixture into a column having a rectifying section and a stripping section, part of the remaining low boilers, mainly acetic acid, being withdrawn via the top of the column, and the (meth) acrylic acid via a Side draw is isolated and the absorbent and high-boiling by-products are obtained in the bottom product.
  • a column having a rectifying section and a stripping section part of the remaining low boilers, mainly acetic acid
  • the (meth) acrylic acid via a Side draw is isolated and the absorbent and high-boiling by-products are obtained in the bottom product.
  • the (meth) acrylic acid can also be taken off overhead, as described in DE-A 22 41 714.
  • a pure (meth) acrylic acid can be generated from this crude (meth) acrylic acid by means of further purification steps, for example crystallization.
  • the crude (meth) acrylic acid generally has a purity of 80-99% by weight, the pure (meth) acrylic acid generally of min. 99.7% by weight.
  • a disadvantage of the methods of the prior art is that in the distillative Separation of the (meth) acrylic acid from the solvent is subject to high thermal stress, which leads to partial polymerization of the (meth) acrylic acid despite the use of large amounts of stabilizer and severely limits the running times of the rectification unit.
  • inhibitors are added in large amounts. However, it is not possible to completely prevent polymerization over a long period of time.
  • the object of the present invention was therefore to provide a process for the distillative removal of (meth) acrylic acid from a mixture which contains (meth) acrylic acid and a high-boiling inert organic absorbent (solvent), which enables long operating times of the distillation unit and avoids the disadvantages of the known methods.
  • the object is achieved according to the invention by a process for the preparation of (meth) acrylic acid from a mixture which contains (meth) acrylic acid and a solvent with a boiling point above the boiling point of (meth) acrylic acid, by distillation of the mixture in a column which comprises is connected to at least one evaporator, the column being an amplifier column, the mixture to which at least one evaporator is fed and (meth) acrylic acid removed from a side draw of the column.
  • solvent is to be understood as a high-boiling inert organic absorbent whose boiling point at normal pressure (1 atm) is above the boiling point of (meth) acrylic acid and is preferably above 161 ° C.
  • the solvent is preferably at least
  • Suitable solvents are, for example, in
  • At least two evaporators are preferably provided, which are connected in series and are connected to a common column.
  • the (rectification) column preferably has 15-60 trays.
  • the mixture to be separated is fed into the first evaporator, which has an overflow to the second evaporator, etc.
  • the return from the column flows into the first evaporator.
  • the (meth) acrylic acid is separated off via a side draw which is located in the rectifying section, preferably below the upper third, in particular below the 5th to 10th tray, counted from the top of the column.
  • the side take-off product is drawn off liquid, whereby if necessary, part of it is fed back to the column below the side draw (lower reflux).
  • the vapors are precipitated with the aid of one or more condensers, part of the distillate preferably being returned to the top of the column as reflux (top reflux).
  • the rectification column can e.g. be a tray, packed or packed column. Tray columns are preferably used. Examples include valve, bell, tunnel, sieve and dual-flow tray columns.
  • the evaporators and the condensers have the embodiments known to the person skilled in the art.
  • the associated temperatures in the evaporators are generally 100 to 230 ° C. and 30 to 80 ° C. at the top of the column.
  • a polymerization inhibitor such as hydroquinone, hydroquinone monomethyl ether, paranitrosophenol, paranitrosodiethylaniline or phenothiazine or a combination thereof, preferably phenothiazine, preferably dissolved in (meth) acrylic acid, is added .
  • the inhibitor solution can be supplied at two points: 1. Directly on the column head or mixed with the upper reflux, the inhibitor concentration in the liquid phase being between the side draw and the head is usually 5 to 500 mg / 1, often 10 to 200 mg / 1 and preferably 20 to 100 mg / 1. 2. In addition, if appropriate, directly below the side draw or directly or mixed with the lower reflux, the inhibitor concentration in the liquid phase on the column trays between the side draw and the
  • Sump is usually 100 to 10000 mg / 1, often from 300 to 1000 mg / 1 and preferably from 300 to 800 mg / 1.
  • the entire amount of inhibitor can also be applied to the top of the column, but the procedure is preferably as described above.
  • the effect of the metered inhibitor can be supported or supplemented by adding oxygen, preferably in the form of air, into the evaporator or evaporators and / or the column.
  • the inhibitor concentration in the column can be varied from top to bottom.
  • a lower inhibitor concentration can be used in the upper part of the column, where there is a lower temperature load, than in the lower part of the column, where the temperature load is higher. In this way, the inhibitor costs can be reduced.
  • thermostable inhibitors it is possible to use other inhibitors in the upper part of the column than in the lower part of the column, where, due to the higher temperatures, more thermostable inhibitors may have to be used.
  • the mixture containing (meth) acrylic acid and the solvent is preferably obtained through
  • a reaction mixture containing acrylic acid was produced by catalytic gas phase oxidation of acrolein according to Example B1 of DE-A 4 302 991.
  • 2.1 NmVh of this reaction mixture were cooled to 170 ° C. in a gas cooler (quench) by injecting a coolant mixture composed of 57.4% by weight of diphenyl ether, 20.7% by weight of diphenyl and 20% by weight of o-dimethylphthalate.
  • the liquid portion of the coolant was then separated from the gas phase consisting of reaction gas and evaporated coolant in a separator.
  • the gas phase which has a temperature of 170 ° C., was passed below the first tray into a bubble cap tray with 27 trays and the countercurrent flow of 3 l / h was also composed of 57.4% by weight of diphenyl ether, 20.7% by weight of diphenyl and 20 % By weight of o-dimethyl phthalate composite, applied at the column top at a temperature of 45 ° C, exposed to absorbent.
  • the outlet of the absorption column was indirectly heated to 105 ° C in a heat exchanger and upside down given a desorption column, which was designed as a bubble tray column with 20 trays.
  • the low-boiling components for example acetic acid and aldehydes, compared to acrylic acid, were largely removed from the mixture by stripping with nitrogen (400 l / h countercurrent).
  • the outlet of the desorption column contains 14.7% by weight of acrylic acid. This was fed at a temperature of 25 ° C. in an amount of 3 l / h into the first evaporator of a distillation unit, which consisted of two evaporators connected in series, a common bubble-cap column with 20 trays and a side draw between the 15th and 16th Ground and a condenser.
  • the first evaporator was connected to the second evaporator by an overflow, the return flow of the column running into the first evaporator.
  • the evaporators were operated at a temperature of 120 ° C and 160 ° C at a pressure of 130 mbar.
  • the top temperature of the column was 60 ° C. at a pressure of 100 mbar.
  • An air flow of 3 l / h was passed into the two evaporators. Via the side draw, 1380 ml of acrylic acid were removed in a purity of 99.7% per hour, and 930 ml of this, mixed with 500 ppm of phenothiazine, were returned to the column below the side draw.
  • the vaporous overhead product was condensed (500 ml / h), stabilized with 150 ppm phenothiazine, and 450 ml / h thereof were again applied to the top of the column. The remaining 50 ml / h were mixed into the outlet of the absorption column.
  • the distillation unit could be operated for 690 hours without any problems.
  • Comparative Example VI The outlet of the desorption column from Example 1 was passed at a temperature of 25 ° C. in an amount of 3 l / h between the fifth and sixth tray (viewed from the evaporator) into a column with 20 bubble trays, which were equipped with an evaporator and was equipped with a capacitor.
  • the rectification column was operated at a bottom temperature of 160 ° C. and a bottom pressure of 130 mbar and a top pressure of 80 mbar.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

L'invention concerne un procédé de préparation d'acide (méth)acrylique à partir d'un mélange contenant de l'acide (méth)acrylique et un solvant dont le point d'ébullition est supérieur à celui de l'acide (méth)acrylique, par distillation dudit mélange dans une colonne, reliée à au moins un évaporateur. Selon ce procédé, la colonne est une colonne d'amplification. Le mélange est acheminé jusqu'à au moins un évaporateur et l'acide (méth)acrylique est prélevé en sortie d'un système de décharge latérale de la colonne.
PCT/EP1998/006460 1997-10-22 1998-10-12 Procede de preparation d'acide (meth)acrylique WO1999020593A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE1997146690 DE19746690A1 (de) 1997-10-22 1997-10-22 Verfahren zur Herstellung von (Meth)acrylsäure
DE19746690.7 1997-10-22

Publications (1)

Publication Number Publication Date
WO1999020593A1 true WO1999020593A1 (fr) 1999-04-29

Family

ID=7846304

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP1998/006460 WO1999020593A1 (fr) 1997-10-22 1998-10-12 Procede de preparation d'acide (meth)acrylique

Country Status (2)

Country Link
DE (1) DE19746690A1 (fr)
WO (1) WO1999020593A1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19838783A1 (de) 1998-08-26 2000-03-02 Basf Ag Verfahren zur kontinuierlichen Gewinnung von (Meth)acrylsäure
US20040104108A1 (en) 2002-12-03 2004-06-03 Mason Robert Michael High capacity purification of thermally unstable compounds

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0722926A1 (fr) * 1995-01-18 1996-07-24 Basf Aktiengesellschaft Procédé de séparation rectificative d'acide (méth)acrylique à partir d'un mélange renferment d'acide (méth)acrylique et des aldéhydes inférieures

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0722926A1 (fr) * 1995-01-18 1996-07-24 Basf Aktiengesellschaft Procédé de séparation rectificative d'acide (méth)acrylique à partir d'un mélange renferment d'acide (méth)acrylique et des aldéhydes inférieures

Also Published As

Publication number Publication date
DE19746690A1 (de) 1999-04-29

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