Acid catalyzed synthesis of methyl acrylate from acrylic acid and methanol

Patent metadata

Field	Value
Publication number	US-12098124-B2
Application number	US-202017600764-A
Country	US
Kind code	B2
Filing date	Apr 2, 2020
Priority date	Apr 16, 2019
Publication date	Sep 24, 2024
Grant date	Sep 24, 2024

Abstract

A method for preparing methyl acrylate comprises:
a) heating in a reaction zone a mixture comprising acrylic acid, methanol, and an acid catalyst to react and form a reaction product comprising methyl acrylate which is vaporized with other light components and then fed to a distillation zone, wherein a feed stream entering the reaction zone comprises methanol to acrylic acid in a molar ratio of greater than 1 and less than 2, and a residence time in the reaction zone ranges from 0.25 to 2 hours; b) condensing and phase-separating a distillate from the distillation zone to form an organic phase comprising methyl acrylate and an aqueous phase; c) returning a portion of the organic phase to the distillation zone as organic reflux; and d) feeding the remainder of the organic phase and the aqueous phase of the distillation zone to an extraction column to form a methanol rich aqueous effluent and an organic effluent comprising methyl acrylate.

First claim

We claim:

1. A method for preparing methyl acrylate, comprising:
a) heating in a reaction zone a mixture comprising acrylic acid, methanol, and an acid catalyst to react and form a product comprising methyl acrylate, which is vaporized with other light components and then fed to a distillation zone, wherein a feed stream entering the reaction zone comprises methanol to acrylic acid in a molar ratio of greater than 1 and less than 2, and a residence time in the reaction zone ranges from 0.25 to 2 hours;
b) condensing and phase-separating a distillate from the distillation zone to form an organic phase comprising methyl acrylate and an aqueous phase;
c) returning a portion of the organic phase to the distillation zone as organic reflux; and
d) feeding the remainder of the organic phase and the aqueous phase of the distillation zone to an extraction column to form a methanol rich aqueous effluent and an organic effluent comprising methyl acrylate.

2. The method according to claim 1 , wherein the acid catalyst is sulfuric acid or a sulfonic acid.

3. The method according to claim 1 , wherein acrylic acid entering the reaction zone as fresh feed comprises less than 2 wt. % impurities.

4. The method according to claim 1 , further comprising feeding the methanol rich aqueous effluent from the extraction column to an alcohol recovery column to form a distillate comprising methanol and a bottoms stream substantially free of organics more volatile than water.

5. The method according to claim 4 , wherein at least a portion of the distillate of the alcohol recovery column is recycled to the reaction zone.

6. The method according to claim 4 , wherein a portion of the bottoms stream of the alcohol recovery column is recycled to the extraction column.

7. The method according to claim 1 , further comprising feeding the organic effluent from the extraction column to a lights removal column to separate the organic effluent into a distillate comprising organics more volatile than methyl acrylate and a bottoms stream.

8. The method according to claim 7 , wherein the distillate comprising organics more volatile than methyl acrylate is at least partially condensed and phase separated into an organic phase and an aqueous phase, wherein at least a portion of the organic phase is returned to the light ends column as organic reflux and at least a portion of the remainder of the organic phase and the aqueous phase are recycled to the extraction column.

9. The method according to claim 7 , wherein the bottoms stream of the light ends column is fed to a refining column to form a product stream comprising methyl acrylate and a bottoms stream comprising heavy components less volatile than methyl acrylate, wherein at least a portion of the bottoms stream of the refining column is recycled to the reaction zone.

10. The method according to claim 1 , wherein the reaction zone is operated at a temperature ranging from 60 to 150 ° C.and the acid catalyst comprises sulfuric acid in an amount ranging from 2 to 8 wt. % relative to the total weight of a bottoms stream exiting the reaction zone.

Assignees

• Rohm & Haas

Inventors

• Chakrabarti Reetam
• Ngo Minh N
• Elder James

Classifications

• B01D3/146

  Multiple effect distillation · CPC title

• C07C69/54

  Acrylic acid esters; Methacrylic acid esters · CPC title

• C07C67/58

  by liquid-liquid treatment · CPC title

• C07C67/54

  by distillation · CPC title

• B01J31/0225

  comprising sulfonic acid groups or the corresponding salts · CPC title