Process for producing methacrylic acid or methacrylic acid esters

Patent metadata

Field	Value
Publication number	US-11905239-B2
Application number	US-202218056338-A
Country	US
Kind code	B2
Filing date	Nov 17, 2022
Priority date	Aug 10, 2018
Publication date	Feb 20, 2024
Grant date	Feb 20, 2024

Abstract

A process can be used for producing methacrylic acid or a methacrylic acid ester. The process involves producing acrolein, reacting the produced acrolein with hydrogen to produce propanal, reacting the propanal with formaldehyde to produce methacrolein, and oxidizing the methacrolein in the presence of an oxygen containing gas and optionally an alcohol, to obtain methacrylic acid or methacrylic acid ester.

First claim

The invention claimed is:

1. A process for producing methacrylic acid or a methacrylic acid ester, the process comprising:
a) producing acrolein from a raw material comprising propylene,
b) reacting the acrolein of a) with hydrogen to produce propanal,
c) reacting the propanal of b) with formaldehyde to produce methacrolein,
d) oxidizing the methacrolein in the presence of an oxygen containing gas and optionally an alcohol, to the methacrylic acid or the methacrylic acid ester, and
wherein the acrolein of a) is hydrogenated in the presence of acrylic acid, which is formed in a) as a byproduct, and wherein the acrylic acid is hydrogenated to propionic acid in b).

2. The process according to claim 1 , wherein the acrolein of a) is produced from oxidation of the propylene in gas phase, at a temperature between 300 and 400° C., in the presence of a catalyst comprising bismuth and molybdenum.

3. A process for producing methacrylic acid or a methacrylic acid ester, the process comprising:
a) producing acrolein from a raw material comprising propylene,
b) reacting the acrolein of a) with hydrogen to produce propanal,
c) reacting the propanal of b) with formaldehyde to produce methacrolein, and
d) oxidizing the methacrolein in the presence of an oxygen containing gas and optionally an alcohol, to the methacrylic acid or the methacrylic acid ester,
wherein acrylic acid, which is formed in a) as a byproduct and/or propionic acid, which is formed in b) from hydrogenation of the acrylic acid in step b) reacts as a co-catalyst in c).

4. The process according to claim 1 , wherein the propylene of a) is evaporated and thereafter converted in the presence of a heterogeneous contact and a co-feed gas comprising at least one component selected from the group consisting of hydrogen, oxygen, and water.

5. The process according to claim 1 , wherein a product of b) is condensed and separated from a gas stream comprising hydrogen and at least two components selected from the group consisting of water, carbon monoxide, carbon dioxide, ethane, ethylene, and propane; and
wherein at least a part of the gas stream is recycled by using the gas stream as a co-feed in at least one of a) or b).

6. The process according to claim 1 , wherein c) is carried out in the presence of from 0.1 to 20 mol % of an organic base, and in the presence of from 0.1 to 20 mol % of an acid, based in each case on the propanal.

7. The process according to claim 1 , wherein d) is an oxidative esterification of methacrolein, which is carried out in a liquid phase at a pressure of from 1 to 100 bar, and in the presence of a heterogeneous noble-metal-comprising catalyst comprising a metal and/or a metal oxide.

8. The process according to claim 7 , wherein the catalyst comprises one or more ultra-finely dispersed metals with an average particle size of less than 20 nm selected from the group consisting of gold, palladium, ruthenium, rhodium, and silver.

9. A process for producing methacrylic acid or a methacrylic acid ester, the process comprising:
a) producing acrolein from a raw material comprising propylene,
b) reacting the acrolein of a) with hydrogen to produce propanal,
c) reacting the propanal of b) with formaldehyde to produce methacrolein, and
d) oxidizing the methacrolein in the presence of an oxygen containing gas and optionally an alcohol, to the methacrylic acid or the methacrylic acid ester,
wherein a) and b) are carried out simultaneously in one reactor.

10. The process according to claim 1 , wherein b) is carried out in the presence of a noble metal catalyst and hydrogen.

11. The process according to claim 6 , wherein the organic base is a secondary amine.

12. The process according to claim 6 , wherein the acid is an organic acid.

13. The process according to claim 6 , wherein a molar ratio of the acid to the organic base ranges from 20:1 to 1:20.

14. The process according to claim 3 , wherein c) is carried out in the presence of from 0.1 to 20 mol % of an organic base, and in the presence of from 0.1 to 20 mol % of an acid, based in each case on the propanal.

15. The process according to claim 9 , wherein c) is carried out in the presence of from 0.1 to 20 mol % of an organic base, and in the presence of from 0.1 to 20 mol % of an acid, based in each case on the propanal.

16. The process according to claim 3 , wherein b) is carried out in the presence of a noble metal catalyst and hydrogen.

17. The process according to claim 9 , wherein b) is carried out in the presence of a noble metal catalyst and hydrogen.

18. The process according to claim 3 , wherein d) is an oxidative esterification of methacrolein, which is carried out in a liquid phase at a pressure of from 1 to 100 bar, and in the presence of a heterogeneous noble-metal-comprising catalyst comprising a metal and/or a metal oxide.

19. The process according to claim 9 , wherein d) is an oxidative esterification of methacrolein, which is carried out in a liquid phase at a pressure of from 1 to 100 bar, and in the presence of a heterogeneous noble-metal-comprising catalyst comprising a metal and/or a metal oxide.

Assignees

• Roehm Gmbh

Inventors

• May Alexander
• Krill Steffen
• Treskow Marcel
• Carambia Diego
• Avella Gabriel

Classifications

• B01J35/45

  Nanoparticles · CPC title

• C07C67/39 Primary

  by oxidation of groups which are precursors for the acid moiety of the ester · CPC title

• B01J23/38

  of noble metals · CPC title

• B01J35/023

  Operations & Transport · mapped topic

• C07C45/75

  Reactions with formaldehyde · CPC title