Processes for preparing 2,5-dichlorophenol

Patent metadata

Field	Value
Publication number	US-11008276-B2
Application number	US-201916724534-A
Country	US
Kind code	B2
Filing date	Dec 23, 2019
Priority date	Oct 2, 2014
Publication date	May 18, 2021
Grant date	May 18, 2021

Abstract

Processes for producing 2,5-dichlorophenol and 3,6-dichloro-2-methoxybenzoic acid are described. Various processes for isomerizing 2,4-dichlorophenol over a zeolite catalyst to form 2,5-dichlorophenol are provided. Processes for preparing 2,5-dichlorophenol including hydroxylating 1,4-dichlorobenzene are also described. The present invention also relates to processes for producing 3,6-dichloro-2-methoxybenzoic acid.

First claim

What is claimed is:

1. A process for producing 2,5-dichlorophenol, the process comprising:
contacting a feed comprising 2,4-dichlorophenol with a zeolite catalyst in acid form in an isomerization zone to isomerize at least a portion of the 2,4-dichlorophenol to 2,5-dichlorophenol, wherein the zeolite catalyst has a SiO 2 /Al 2 O 3 mole ratio of no greater than about 35:1.

2. The process of claim 1 wherein the SiO 2 /Al 2 O 3 mole ratio is from about 23:1 to about 35:1.

3. The process of claim 1 wherein the zeolite catalyst comprises at least one alumino-silicate zeolite selected from the group consisting of ZSM zeolites, Beta zeolites, Y zeolites, and mixtures thereof.

4. The process of claim 1 wherein the zeolite catalyst comprises a HZ SM-5 zeolite, a HZ SM-11 zeolite, or a mixture thereof.

5. The process of claim 1 further comprising feeding water to the isomerization zone.

6. The process of claim 1 wherein the isomerization is conducted at a catalyst temperature of from about 220° C. to about 550° C.

7. The process of claim 1 wherein the zeolite catalyst is calcined at a temperature in the range of from about 500° C. to about 1000° C.

8. The process of claim 1 wherein the zeolite catalyst is selected from the group consisting of pentasil zeolites, Beta zeolites, and faujasite zeolites.

9. A process for producing 2,5-dichlorophenol, the process comprising:
contacting a feed comprising 2,4-dichlorophenol and 3,4-dichlorophenol with a zeolite catalyst in acid form in an isomerization zone to isomerize at least a portion of the 2,4-dichlorophenol to 2,5-dichlorophenol.

10. The process of claim 9 wherein the zeolite catalyst comprises a HZ SM-5 zeolite, a HZ SM-11 zeolite, or a mixture thereof.

11. The process of claim 9 further comprising feeding water to the isomerization zone.

12. The process of claim 9 wherein the mole ratio of 2,4-dichlorophenol to 3,4-dichlorophenol in the feed is from about 10:1 to about 50:1.

13. The process of claim 9 wherein the zeolite catalyst comprises a desilicated zeolite catalyst.

14. The process of claim 13 wherein the desilicated zeolite catalyst has a meso-macro pore volume (attributable to pores that have diameters greater than 20 Å up to 2500 Å) from about 50% to about 500% greater than the meso-macro pore volume of the initial zeolite catalyst before desilication.

15. A process for producing 3,6-dichloro-2-methoxybenzoic acid comprising:
isomerizing 2,4-dichlorophenol to 2,5-dichlorophenol in accordance with the process of claim 9 ;
carboxylating at least a portion of the 2,5-dichlorophenol to produce 2-hydroxy-3,6-dichlorobenzoic acid; and
methylating the 2-hydroxy-3,6-dichlorobenzoic acid to 3,6-dichloro-2-methoxybenzoic acid.

16. The process of claim 9 wherein the zeolite catalyst is selected from the group consisting of pentasil zeolites, Beta zeolites, and faujasite zeolites.

17. A process for producing 2,5-dichlorophenol, the process comprising:
contacting a feed comprising 2,4-dichlorophenol with a zeolite catalyst in acid form in an isomerization zone to isomerize at least a portion of the 2,4-dichlorophenol to 2,5-dichlorophenol;
suspending contact of the feed comprising 2,4-dichlorophenol with the zeolite catalyst; and
contacting the zeolite catalyst with steam at a temperature from about 250° C. to about 375° C. to rejuvenate the catalyst.

18. The process of claim 17 wherein the zeolite catalyst comprises at least one alumino-silicate zeolite selected from the group consisting of ZSM zeolites, Beta zeolites, Y zeolites, and mixtures thereof.

19. The process of claim 17 wherein the zeolite catalyst comprises a HZ SM-5 zeolite, a HZ SM-11 zeolite, or a mixture thereof.

20. The process of claim 17 wherein the zeolite catalyst comprises a desilicated zeolite catalyst.

21. The process of claim 20 wherein the desilicated zeolite catalyst has a meso-macro pore volume (attributable to pores that have diameters greater than 20 Å up to 2500 Å) from about 50% to about 500% greater than the meso-macro pore volume of the initial zeolite catalyst before desilication.

22. A process for producing 3,6-dichloro-2-methoxybenzoic acid comprising:
isomerizing 2,4-dichlorophenol to 2,5-dichlorophenol in accordance with the process of claim 17 ;
carboxylating at least a portion of the 2,5-dichlorophenol to produce 2-hydroxy-3,6-dichlorobenzoic acid; and
methylating the 2-hydroxy-3,6-dichlorobenzoic acid to 3,6-dichloro-2-methoxybenzoic acid.

23. The process of claim 17 wherein the zeolite catalyst is selected from the group consisting of pentasil zeolites, Beta zeolites, and faujasite zeolites.

Assignees

• Monsanto Technology Llc

Inventors

• Ahn John H
• Probst Don
• Wan Kam-To
• Wang John

Classifications

• C07C39/30

  the halogen being two chlorine atoms · CPC title

• C07C51/16

  by oxidation (C07C51/145 takes precedence) · CPC title

• C07C51/367 Primary

  by introduction of functional groups containing oxygen only in singly bound form · CPC title

• C07C37/00

  Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring · CPC title

• C07C51/00

  Preparation of carboxylic acids or their salts, halides or anhydrides (of acids by hydrolysis of oils, fats or waxes C11C) · CPC title