Process for the preparation of 1-chloro-2,2-difluoroethane

Patent metadata

Field	Value
Publication number	US-9884797-B2
Application number	US-201415533406-A
Country	US
Kind code	B2
Filing date	Dec 11, 2014
Priority date	Dec 11, 2014
Publication date	Feb 6, 2018
Grant date	Feb 6, 2018

Abstract

The present invention provides a process for the preparation of 1-chloro-2,2-difluoroethane comprising the following stages: (i) dehydrofluorinating 1,1,1-trifluoro-2-chloroethane to form a product stream comprising 1-chloro-2,2-difluoroethylene, optionally separation of 1-chloro-2,2-difluoroethylene from the product stream and (ii) hydrogenating 1-chloro-2,2-difluoroethylene obtained in stage (i) to give 1-chloro-2,2-difluoroethane.

First claim

The invention claimed is:

1. A process for the preparation of 1-chloro-2,2-difluoroethane comprising the following stages:
(i) dehydrofluorinating 1,1,1-trifluoro-2-chloroethane to form a first product stream comprising 1-chloro-2,2-difluoroethylene, and
(ii) hydrogenating 1-chloro-2,2-difluoroethylene obtained in stage (i) to produce a second product stream comprising 1-chloro-2,2-difluoroethane.

2. The process according to claim 1 wherein stage (i) is carried out, in the liquid or gas phase, in the presence of a dehydrofluorinating agent or as a thermal decomposition.

3. The process according to claim 2 wherein the dehydrofluorinating agent is a base.

4. The process according to claim 3 wherein the base is an alkali or alkaline earth metal hydroxide.

5. The process according to claim 3 , wherein the dehydrofluorinating agent is in a solid state, a molten state, or an aqueous or nonaqueous caustic solution.

6. The process according to claim 5 wherein a caustic solvent for the caustic solution is water.

7. The process according to claim 3 wherein stage (i) is conducted in the presence of a catalyst.

8. The process according to claim 1 wherein stage (i) is conducted at a temperature in a range from 20 to 300° C. in the absence of a catalyst.

9. The process according to claim 7 wherein stage (i) is conducted at a temperature in a range from 150 to 650° C.

10. The process according to claim 2 wherein stage (i) is a thermal decomposition, conducted at a temperature in a range from 350 to 1000° C. in the absence of a dehydrofluorinating agent.

11. The process according to claim 2 , further comprising recovering the dehydrofluorinating agent after stage (i).

12. The process according to claim 1 wherein stage (ii) is conducted in the presence of a catalyst.

13. The process according to claim 1 wherein the 1-chloro-2,2-difluoroethylene obtained in stage (i) is diluted with an inert gas or by recycle of at least a part of the second product stream.

14. The process according to claim 1 wherein stage (ii) is conducted at an inlet temperature from 20° C. to 250° C.

15. The process according to claim 1 , further comprising purifying 1-chloro-2,2-difluoroethane after stage (ii).

16. The process according to claim 1 , further comprising separating 1-chloro-2,2-difluoroethylene from the first product stream after step (i).

Assignees

• Arkema France

Inventors

• Wendlinger Laurent

Classifications

• C07C17/354 Primary

  by hydrogenation · CPC title

• C07C17/25 Primary

  by splitting-off hydrogen halides from halogenated hydrocarbons · CPC title

• C07C17/38

  Separation; Purification; Stabilisation; Use of additives · CPC title

• Y02P20/582

  Recycling of unreacted starting or intermediate materials · CPC title