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Method for producing high purity extractive (methyl) acrylic acid

An acrylic acid, high-purity technology, applied in the preparation of carboxylates, the preparation of organic compounds, chemical instruments and methods, etc., can solve the problems of poor removal effect, a large amount of residues, expensive alkyl mercaptans, etc., and achieves a small amount of addition. , low price, low cost effect

Active Publication Date: 2008-07-16
SHANGHAI HUAYI NEW MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although no deposits are formed in this method, alkyl mercaptans are more expensive, coupled with more expensive and non-renewable resin catalysts, resulting in higher costs for acrylic acid dealdehyde treatment; in addition, resin catalysts need to be replaced regularly, and the operation is more cumbersome
Rohm and Haas patent CN1149573A reports that various amine compounds are added to different parts of the rectification tower to remove aldehydes, but this method not only generates a large amount of residue, but also has poor removal effect on aldehydes and maleic acid in crude acrylic acid , especially maleic acid is difficult to remove
[0005] The present invention is in order to overcome the shortcoming of above-mentioned patent, promptly the deposit that generates after the dealdehyde reaction blocks the system and influences continuous production, and the effect of dealdehyde especially removing maleic acid is poor, has selected guanidine compound or its salt and urea or Thiourea compounds form a composite formaldehyde removal agent, which reacts with impurity aldehydes and maleic acid in crude (meth)acrylic acid to generate a high-boiling compound that is soluble in (meth)acrylic acid. During distillation, due to the boiling point of these compounds Higher and stay at the bottom of the kettle, so as to achieve the purpose of removing aldehyde and maleic acid

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1-8

[0015] Add 300 grams of thick acrylic acid containing 120ppm furfural, 20ppm acrolein, 150ppm benzaldehyde, 2000ppm maleic acid in a three-necked flask of 500mml, and account for the polymerization inhibitor hydroquinone of 1000ppm of the quality of raw materials used, then add formaldehyde removal agent, The reaction time is 20 minutes at a temperature of 50° C., and then a 500 mml three-necked flask is connected to a packed distillation column equivalent to 10 theoretical plates for rectification to obtain a refined acrylic acid product. The purity of the refined acrylic acid product is analyzed by gas chromatography internal standard method, and the moisture content is determined by an automatic moisture analyzer.

[0016] A compound composed of guanidine compounds or their salts and urea or thiourea compounds was used as the dealdehyde agent, and the test results are shown in Table 1. Apparently, the content of impurity aldehydes and maleic acid in the purified acrylic aci...

Embodiment 9-16

[0024] Add 300 grams of thick methacrylic acid containing 60ppm furfural, 20ppm methacrolein, 1000ppm maleic acid in a 500ml three-necked flask, and account for the polymerization inhibitor hydroquinone of 1000ppm of the raw material quality used, then add the formaldehyde removal agent, The reaction time is 20 minutes at a temperature of 50° C., and then a 500 mml three-neck flask is connected with a packed distillation column equivalent to 10 theoretical plates for rectification to obtain a refined methacrylic acid product. The purity of refined methacrylic acid product was analyzed by gas chromatography internal standard method, and the moisture content was determined by an automatic moisture analyzer.

[0025] A compound composed of a guanidine compound or its salt and a urea or thiourea compound was used as a formaldehyde removal agent, and the test results are shown in Table 3. Obviously, the content of impurity aldehydes and maleic acid in the purified methacrylic acid ...

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PUM

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Abstract

The invention relates to a method for preparing high-purity fine (methyl) acrylic acid, which adds a composite ethyleneurea consisting of a guanidine compound or the salt or urea or thiourea of the guanidine compound into crude (methyl) acrylic acid to react, then introduces the reaction liquid to a distillation column to carry out intermittent or continuous distillation to obtain a high-purity fine (methyl) acrylic acid product which contains no aldehyde and maleic. The composite ethyleneurea can remove the aldehyde and maleic in the crude (methyl) acrylic acid completely with no solid impurity generating.

Description

technical field [0001] The invention provides a method for preparing high-purity (meth)acrylic acid, that is, a method for removing impurity aldehyde and maleic acid in crude (meth)acrylic acid by adding a compound dealdehyde agent. Specifically, the present invention relates to the addition of guanidine compounds and urea or thioureas to crude (meth)acrylic acid containing impurities such as about 10 to 5000 ppm (meth)acrolein, furfural, benzaldehyde and / or maleic acid. Compound dealdehyde agent composed of compound, make it react with aldehyde and maleic acid in crude (meth)acrylic acid, then intermittently or continuously rectify under vacuum to obtain high-purity (meth)acrylic acid free of aldehyde and maleic acid )acrylic acid. Background technique [0002] In propane, propylene, isopropanol and / or acrolein etc. C 3 Compounds or isobutane, isobutene, tert-butanol and / or methacrolein 4 A variety of by-products are generated during the catalytic oxidation of the compou...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C57/07C07C51/487
Inventor 刘书举张庆怀张春雷马建学邵敬铭
Owner SHANGHAI HUAYI NEW MATERIAL
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