Processes for purification, recovery, and conversion of chlorophenol salts and preparation and recovery of products prepared therefrom

Patent metadata

Field	Value
Publication number	US-12240807-B2
Application number	US-202318115127-A
Country	US
Kind code	B2
Filing date	Feb 28, 2023
Priority date	Dec 7, 2016
Publication date	Mar 4, 2025
Grant date	Mar 4, 2025

Abstract

The present invention generally relates to processes for purification, recovery, and conversion of chlorophenol salts (e.g., 2,5-dichlorophenol and salts thereof). In various aspects, the present invention is related to removing one or more impurities from chlorophenol salt-containing process streams and/or recovering chlorophenol salts from process streams for use of the recovered chlorophenol elsewhere in an integrated process. Process streams that may be treated in accordance with the present invention include those incorporating one or more chlorophenol salts in a feed mixture and also those where one or more chlorophenol salts are present in a product or by-product stream of an integrated process. For example, conversion processes of the present invention are suitable as one piece of an integrated process for producing 3,6-dichloro-2-methoxybenzoic acid (dicamba) or a salt or ester thereof or a process for producing 2,4-dichlorophenoxyacetic acid (2,4-D) or a salt or ester thereof. The present invention further relates to processes for preparation, purification, and recovery of intermediates formed in integrated processes utilizing chlorophenol salts such as 2,5-dichlorophenol as starting material, including the intermediate 3,6-dichlorosalicylic acid (3,6-DCSA) formed during preparation of dicamba from 2,5-dichlorophenol.

First claim

What is claimed is:

1. A process for removing impurities from a feed mixture comprising 2,5-dichlorophenol (2,5-DCP) and/or a salt thereof, the process comprising:
heating the 2,5-DCP feed mixture to a temperature of at least about 25° C., the 2,5-DCP feed mixture comprising an organic solvent, 2,5-DCP, 2,5-dichloro-4-nitrophenol (2,5-DCNP), and a plurality of chlorophenol dimers;
feeding the 2,5-DCP feed mixture into a first extraction zone;
contacting the feed mixture within the first extraction zone with a first aqueous solution comprising a base, thereby forming a first organic phase extract comprising the organic solvent, 2,5-DCP and the plurality of chlorophenol dimers and forming a first aqueous phase extract comprising 2,5-DCNP and/or salts thereof, the first aqueous phase extract being enriched in 2,5-DCNP and/or salts thereof as compared to the first organic phase extract and the 2,5-DCP feed mixture;
feeding the first organic phase extract into a second extraction zone and contacting the first organic phase extract with a second aqueous solution comprising a base, thereby forming a second organic phase extract comprising the chlorophenol dimers and forming a second aqueous phase extract comprising 2,5-DCP and/or salts thereof, the second organic phase extract enriched in the chlorophenol dimers as compared to the first organic phase extract and the second aqueous phase extract enriched in 2,5-DCP as compared to the first organic phase extract, wherein the plurality of chlorophenol dimers comprise meta-(chloro-(2,5dichlorophenoxy) phenol) (Meta-CDPP) and ortho-(chloro-(2,5dichlorophenoxy) phenol) (Ortho-CDPP) and the second organic phase extract contains at least about 50 wt % of the dimers present in the first organic phase extract.

2. The process of claim 1 wherein the second aqueous phase extract contains at least about 90 wt % of the 2,5-DCP present in the first organic phase extract.

3. The process of claim 1 wherein the pH of the second aqueous phase extract is at least about 7.1.

4. The process of claim 1 wherein the second aqueous solution comprises the base in a molar ratio to 2,5-DCP present in the first organic phase extract of at least about 0.5:1.

5. The process of claim 1 wherein the concentration of base in the second aqueous solution is from about 1 wt % to about 45 wt %.

6. The process of claim 1 wherein the first extraction zone comprises at least 10 stages.

7. The process of claim 1 wherein the base of the first aqueous solution comprises an alkali or alkaline earth hydroxide, carbonate, or bicarbonate.

8. The process of claim 1 wherein the base constitutes less than about 2 wt % of the first aqueous solution.

9. The process of claim 1 wherein the base constitutes from about 0.01 wt % to about 2 wt % of the first aqueous solution.

10. The process of claim 1 wherein the molar ratio of base to 2,5-DCNP present in the feed mixture is from about 0.5:1 to about 5:1.

11. The process of claim 1 , wherein the first organic phase extract contains at least about 90% of the 2,5-DCP present in the feed mixture.

12. The process of claim 1 , wherein the first aqueous phase extract contains at least about 90% of the 2,5-DCNP present in the feed mixture.

13. The process of claim 1 , wherein the pH of the first aqueous phase extract is less than about 8.

Assignees

• Monsanto Technology Llc

Inventors

• Berk Howard C
• De Kort Bruno
• Parlow John Joseph
• Stroman Amy E
• Yang Junqiu

Classifications

• C07C37/685 Primary

  Processes comprising at least two steps in series · CPC title

• Y02P20/10

  Process efficiency · CPC title

• C07C51/48

  by liquid-liquid treatment · CPC title

• C07C51/15 Primary

  by reaction of organic compounds with carbon dioxide, e.g. Kolbe-Schmitt synthesis · CPC title

• C07C37/80

  by extractive distillation · CPC title