Process for producing 1-chloro-2,2-difluoroethane

Patent metadata

Field	Value
Publication number	US-9981891-B2
Application number	US-201415101733-A
Country	US
Kind code	B2
Filing date	Nov 28, 2014
Priority date	Dec 4, 2013
Publication date	May 29, 2018
Grant date	May 29, 2018

Abstract

The present invention relates to the field of saturated fluorohydrocarbons. The subject matter thereof is more particularly the production of 1-chloro-2,2-difluoroethane from 1,1,2-trichloroethane and/or 1,2-dichloroethylene. A process for producing 1-chloro-2,2-difluoroethane from 1,1,2-trichloroethane and/or 1,2-dichloroethylene including (i) at least one step during which the 1,1,2-trichloroethane and/or the 1,2-dichloroethylene reacts or react with hydrofluoric acid in the gas phase, optionally in the presence of an oxidizing agent, in the presence or in the absence of a fluorination catalyst, to give a stream including 1-chloro-2,2-difluoroethane, hydrochloric acid, hydrofluoric acid and at least one C compound(s) chosen from 1-chloro-2-fluoroethylenes (cis and trans), 1,2-dichloro-2-fluoroethane and, optionally, unreacted 1,1,2-trichloroethane and/or 1,2-dichloroethylene.

First claim

The invention claimed is:

1. A process for manufacturing 1-chloro-2,2-difluoroethane from 1,1,2-trichloroethane and/or 1,2-dichloroethylene, comprising at least one step during which 1,1,2-trichloroethane and/or 1,2-dichloroethylene react(s) with hydrofluoric acid in the gas phase in the presence of an oxidizing agent, and in the presence or absence of a fluorination catalyst, to give a stream comprising 1-chloro-2,2-difluoroethane, hydrochloric acid, hydrofluoric acid and at least one compound C selected from the group consisting of 1-chloro-2-fluoroethylenes (cis and trans), 1,2-dichloro-2-fluoroethane and optionally unreacted 1,1,2-trichloroethane and 1,2-dichloroethylene.

2. A process for manufacturing 1-chloro-2,2-difluoroethane from 1,1,2-trichloroethane, comprising:
(i) at least one step during which 1,1,2-trichloroethane reacts with hydrofluoric acid in the gas phase in the presence of an oxidizing agent, and in the presence or absence of a fluorination catalyst, to give a stream comprising 1-chloro-2,2-difluoroethane, hydrochloric acid, hydrofluoric acid and at least one compound C selected from the group consisting of 1,2-dichloroethylenes (cis and trans), 1-chloro-2-fluoroethylenes (cis and trans), 1,2-dichloro-2-fluoroethane and optionally unreacted 1,1,2-trichloroethane;
(ii) at least one step of separating the compounds derived from the reaction step to give a stream A comprising hydrochloric acid and a stream B comprising hydrofluoric acid, 1-chloro-2,2-difluoroethane, at least one compound C and optionally 1,1,2-trifluoroethane;
(iii) at least one step of separating the stream B to give an organic phase comprising 1-chloro-2,2-difluoroethane, at least one compound C and optionally unreacted 1,1,2-trichloroethane and a non-organic phase predominantly comprising HF;
(iv) at least one step of separating the 1-chloro-2,2-difluoroethane from the organic phase obtained in (iii);
(v) optionally, recycling into step (i) of the organic phase after the separation of step (iv); and
(vi) optionally, recycling into step (i) of the non-organic phase derived from step (iii).

3. The process as claimed in claim 2 , wherein, after the step of separating out the 1-chloro-2,2-difluoroethane, the organic phase comprises 1-chloro-2-fluoroethylene, 1,2-dichloroethylenes (cis and trans) and 1,2-dichloro-2-fluoroethane.

4. The process as claimed in claim 2 , wherein the non-organic phase derived from step (iii) is purified such that the HF content is greater than or equal to 90% by weight before recycling into step (i).

5. The process as claimed in claim 4 , wherein the purification comprises at least one distillation, performed at a temperature of between −23 and 46° C. and an absolute pressure of between 0.3 and 3 bar.

6. The process as claimed in claim 2 , wherein the separation step (ii) comprises at least one distillation, performed at a temperature of between −60 and 120° C. and an absolute pressure of between 3 and 20 bar.

7. The process as claimed in claim 2 , wherein the separation step (iii) comprises at least one decantation step, performed at a temperature of between −20 and 60° C.

8. The process as claimed in claim 2 , wherein the separation step (iv) comprises at least one distillation, performed at a temperature of between 35 and 79° C. and an absolute pressure of between 0.3 and 4 bar.

9. The process as claimed in claim 1 , wherein the temperature of the reaction step is between 150 and 400° C.

10. The process as claimed in claim 1 , wherein the pressure at which the fluorination reaction is performed is between 1 and 20 bar absolute.

11. The process as claimed in claim 1 , wherein the amount of hydrofluoric acid used in the reaction is between 5 and 40 mol per mole of HCC-140 and/or 1,2-dichloroethylene.

12. The process as claimed in claim 1 , wherein the oxidizing agent is selected from the group consisting of oxygen and chlorine.

13. The process as claimed in claim 12 , wherein the amount of oxidizing agent used is between 0.01 mol % and 20 mol % per mole of HCC-140 and/or 1,2-dichloroethylene.

14. A composition of the azeotropic or quasi-azeotropic type comprising from 80 mol % to 95 mol % of 1-chloro-2,2-difluoroethane and from 5 mol % to 20 mol % of trans-1,2-dichloroethylene.

15. A composition of the azeotropic or quasi-azeotropic type comprising 1-chloro-2,2-difluoroethane and trans-1,2-dichloroethylene, wherein the boiling point is between 32 and 119° C. at a pressure of between 1 and 10 bar abs.

16. The composition as claimed in claim 14 , wherein the boiling point is between 32 and 119° C. at a pressure of between 1 and 10 bar abs.

Assignees

• Arkema France

Inventors

• Bonnet Philippe
• Collier Bertrand
• Garrait Dominique
• Sedat Pierre-Marie

Classifications

• C07B2200/09

  Geometrical isomers · CPC title

• C07C17/206 Primary

  the other compound being HX · CPC title

• C07C17/383

  by distillation · CPC title

• C07C19/12

  having two carbon atoms · CPC title

• C07C17/21

  with simultaneous increase of the number of halogen atoms · CPC title