Process for the separation of 2-chloro-1,1-difluoroethane and trans-dichloroethylene

Patent metadata

Field	Value
Publication number	US-10227277-B2
Application number	US-201615551789-A
Country	US
Kind code	B2
Filing date	Feb 15, 2016
Priority date	Feb 17, 2015
Publication date	Mar 12, 2019
Grant date	Mar 12, 2019

Abstract

The invention relates to the separation of a mixture comprising 2-chloro-1,1-difluoroethane (R142) and trans-dichloroethylene (TDCE) by extractive distillation and more particularly to a separation process wherein the TDCE is removed selectively by extractive distillation, thus leading to purified 2-chloro-1,1-difluoroethane.

First claim

The invention claimed is:

1. A process for the separation of a mixture comprising 2-chloro-1,1-difluoroethane and trans-dichloroethylene by extractive distillation.

2. The separation process according to claim 1 , wherein the 2-chloro-1,1-difluoroethane/trans-dichloroethylene molar ratio before extractive distillation ranges from 2 to 100.

3. The separation process according to claim 1 , wherein the 2-chloro-1,1-difluoroethane/trans-dichloroethylene molar ratio after extractive distillation ranges from 9 to 99.999.

4. The separation process according to claim 1 , wherein the extractive distillation is carried out under a pressure ranging from 0.05 bar to 10 bar.

5. The separation process according to claim 1 , wherein the extractive distillation is carried out at a temperature ranging from −50° C. to 250° C.

6. The separation process according to claim 1 , wherein the extractive distillation is carried out using an extracting agent/product to be removed molar ratio ranging from 0.01 to 20.

7. The separation process according to claim 1 , wherein the mixture comprising 2-chloro-1,1-difluoroethane and trans-dichloroethylene originates from a fluorination reaction of 1,1,2-trichloroethane.

8. The separation process according to claim 1 , wherein an extraction agent is utilized, consisting of compounds having a boiling point greater than 35° C.

9. The separation process according to claim 1 , wherein an extraction agent is utilized, having a dipole moment less than or equal to 5 Debye.

10. The separation process according to claim 8 , wherein the separation factor of the 2-chloro-1,1-difluoroethane and trans-dichloroethylene in the extraction agent is greater than 1.1.

11. The separation process according to claim 8 , wherein the separation factor of the 2-chloro-1,1-difluoroethane and trans-dichloroethylene in the extraction agent is less than 1.

12. The separation process according to claim 8 , wherein the extraction agent is a hydrocarbon selected from the linear, branched or non-branched, cyclic or aromatic, saturated or unsaturated hydrocarbons, optionally substituted.

13. The separation process according to claim 12 , wherein the optionally substituted hydrocarbons have from 1 to 12 carbon atoms.

14. The separation process according to claim 12 , wherein the hydrocarbons are substituted with at least one substituent chosen from an oxygen atom, a nitrogen atom, a halogen atom, an alcohol group, an amine group.

15. The separation process according to claim 8 , wherein the extraction agent is chosen from the linear, branched, cyclic or aromatic hydrocarbons comprising from 6 to 8 carbon atoms.

16. The separation process according to claim 15 , wherein the extraction agent is chosen from hexane, cyclohexane, methylcyclohexane, n-heptane, octane, 2-methylpentane or toluene.

17. The separation process according to claim 8 , wherein the extraction agent is chosen from the halogenated hydrocarbons comprising from 2 to 4 halogen atoms.

18. The separation process according to claim 17 , wherein the halogenated hydrocarbons are chosen from tetrachloromethane, 1,1,2-trichloroethane, 1,1,1-trichloroethane, tetrachloroethene, 1,1,2,2-tetrachloroethane, 1,1,1,2-tetrachloroethane, trichloroethene, tribromomethane or triiodomethane, preferably 1,1,2-trichloroethane and tetrachloroethene.

19. The separation process according to claim 7 , wherein the extraction agent is 1,1,2-trichloroethane originating from said fluorination reaction.

Assignees

• Arkema France

Inventors

• Garrait Dominique
• Andre David
• Baba-Ahmed Abdelatif
• Herdt Charlotte

Classifications

• C07C17/383 Primary

  by distillation · CPC title

• C07C17/386 Primary

  with auxiliary compounds · CPC title

• C07C21/073

  Dichloro-alkenes · CPC title

• C07C19/12

  having two carbon atoms · CPC title