Method for purifying acrylic acid

A technology of acrylic acid and acetic acid, applied in the separation/purification of carboxylic acid compounds, organic chemistry, etc., which can solve the problems of increasing the difficulty and complexity of extraction operations

Active Publication Date: 2004-11-17
SHANGHAI HUAYI NEW MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage of this patent is that toxic or gaseous substances are used as extraction agents, which increases the difficulty of extraction operations
CN 97197080 patent uses biphenyl, diphenyl ether or dimethyl phthalate as extraction agent, and its disadvantage is that the extraction operation is complicated and needs to be carried out in multiple steps

Method used

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  • Method for purifying acrylic acid

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] Table 1 Extraction effect of each extractant

[0018] No. Extractant Extractant / crude acrylic acid solution (mass ratio) Extraction rate (wt%)

[0019] 1 Isobutyl acetate 1:1 95.55

[0020] 2 isopropyl ether 1:1 94.00

[0021] 3 butyl acetate 1:1 93.98

[0022] 4 Propyl acetate 1:1 93.56

[0023] 5 toluene 1:1 58.58

[0024] As can be seen from Table 1, in the single extractant tested, the extraction effect of isobutyl acetate is the best. Isopropyl ether is next, and butyl acetate is third.

Embodiment 2

[0026] Table 2 Extraction effect of compound extractant

[0027] No. Extractant Extractant / crude acrylic acid solution (mass ratio) Extraction rate (wt%)

[0028] 1 toluene / isobutyl acetate 3:1 98.48

[0029] 2 toluene / butyl acetate 3:1 98.25

[0030] 3 toluene / isopropyl acetate 3:1 97.24

[0031] It can be seen from Table 2 that among the tested compound extractants, the extraction effect of toluene / isobutyl acetate is the best, and the extraction rate can reach 98.48%, which is better than the extraction effect of toluene / butyl acetate.

Embodiment 3

[0033] Table 3 Extraction effect of extractant under different extraction ratio

[0034] Toluene: isobutyl acetate: crude acrylic acid solution (mass ratio) extraction rate (wt%)

[0035] 2:1:1 87.50

[0036] 1.5:1.5:1 96.63

[0037] 1:2:1 98.48

[0038] As can be seen from Table 3, when the extraction ratio is 1:2:1, the extraction effect of toluene / isobutyl acetate is the best.

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Abstract

The invention relates to the process for purifying acrylic acid which comprises using novel organic extracting agent to separate acrylic acid from its water solution, then removing light compositions such as water and acetic acid by azeotropic fractional distillation, wherein the organic extracting agent comprises toluene, acetic ether, butyl acetate, butyl acetate, propionic ether, diisobutyl ketone, isophorone, methyl phenyl ether or their mixture, preferably the composite compound of toluene with isobutyl phenylacetate, the mass ratio of toluene and isobutyl phenylacetate is between 1:1-1:50, preferably 1:2-1:12. The process according to the invention can realize high acetic acid removing ratio.

Description

technical field [0001] The present invention relates to a method for purifying acrylic acid. Background technique [0002] Acrylic acid is produced by gas-phase oxidation of propylene and / or acrolein under the action of a catalyst. The gaseous product is cooled and absorbed by water to obtain an aqueous acrylic acid solution containing 25-50% acrylic acid. In addition to acrylic acid, there are acetic acid and various other trace impurities in the aqueous acrylic acid solution, such as formaldehyde, acrolein, propionic acid, acetone, maleic acid, furfural and acrylic acid dimer. It is quite difficult to separate acrylic acid from its aqueous solution directly by simple rectification method, because acrylic acid and water easily form azeotrope, which makes dehydration difficult. In addition, acrylic acid is prone to self-polymerization, resulting in a decrease in yield. In industry, azeotropic dehydration and solvent extraction are usually used to refine and purify acrylic...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C51/48C07C57/07
Inventor 马建学吴滨刘书举
Owner SHANGHAI HUAYI NEW MATERIAL
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