Processes for producing Z-1,1,1,4,4,4-hexafluorobut-2-ene and intermediates for producing same

1. A process for producing 2,2-dichloro-1,1,1,4,4,4-hexafluorobutane comprising: contacting 2-chloro-1,1,1,4,4,4-hexafluorobutane with a chlorine source.

2. The process of claim 1 wherein the chlorine source is Cl 2 and the process is performed in the absence of a catalyst.

3. The process of claim 1 further comprising recovering 2,2-dichloro-1,1,1,4,4,4-hexafluorobutane.

4. The process of claim 1 wherein 2-chloro-1,1,1,4,4,4-hexafluorobutane is produced by contacting 1,1,2,4,4-pentachlorobuta-1,3-diene with HF in the liquid phase in the presence of a fluorination catalyst.

5. The process of claim 4 further comprising recovering 2-chloro-1,1,1,4,4,4-hexafluorobutane.

6. The process of claim 4 wherein 1,1,2,4,4-pentachlorobuta-1,3-diene is produced by contacting trichloroethylene in the presence of a dimerization catalyst.

7. The process of claim 4 wherein 1,1,2,4,4-pentachlorobuta-1,3-diene is produced by contacting trichloroethylene in the presence of a dimerization catalyst and pentachloroethane.

8. The process of claim 1 further comprising contacting 2,2-dichloro-1,1,1,4,4,4-hexafluorobutane with base to produce a product mixture comprising 1,1,1,4,4,4-hexafluoro-2-butyne.

9. The process of claim 8 further comprising recovering 1,1,1,4,4,4-hexafluoro-2-butyne.

10. The process of claim 8 further comprising contacting 1,1,1,4,4,4-hexafluoro-2-butyne with hydrogen to produce a product mixture comprising Z-1,1,1,4,4,4-hexafluoro-2-butene.

11. The process of claim 10 further comprising recovering Z-1,1,1,4,4,4-hexafluoro-2-butene.

12. The process of claim 10 wherein 1,1,1,4,4,4-hexafluoro-2-butyne is contacted with hydrogen in the presence of an alkyne-to-alkene catalyst, wherein the alkyne-to-alkene catalyst is a palladium catalyst at a concentration of 100-5000 ppm dispersed over aluminum oxide, silicon carbide, or titanium silicates with a Ag or lanthanide poison.

13. A process for producing Z-1,1,1,4,4,4-hexafluoro-2-butene comprising:

(a) contacting trichloroethylene with a dimerization catalyst to produce a product mixture comprising 1,1,2,4,4-pentachlorobuta-1,3-diene;

(b) contacting 1,1,2,4,4-pentachlorobuta-1,3-diene with HF in the liquid phase in the presence of a fluorination catalyst in the liquid phase to form a product mixture comprising 2-chloro-1,1,1,4,4,4-hexafluorobutane,

(c) contacting 2-chloro-1,1,1,4,4,4-hexafluorobutane with a chlorine source to form a product mixture comprising 2,2-dichloro-1,1,1,4,4,4-hexafluorobutane;

(d) contacting 2,2-dichloro-1,1,1,4,4,4-hexafluorobutane with base to produce a product mixture comprising 1,1,1,4,4,4-hexafluoro-2-butyne; and

(e) contacting 1,1,1,4,4,4-hexafluoro-2-butyne with hydrogen produce a product mixture comprising Z-1,1,1,4,4,4-hexafluoro-2-butene.

14. The process of claim 13 further comprising recovering Z-1,1,1,4,4,4-hexafluoro-2-butene from the product mixture of step (e).

15. A composition comprising 2-chloro-1,1,1,4,4,4-hexafluorobutane, Z-1,1,1,4,4,4-hexafluoro-2-chloro-2-butene, 1,2-dichloro-1,1,4,4,4-pentafluorobutane, E-1,1,1,4,4,4-hexafluoro-2-butene, and 1,1-dichloro-2,2,4,4,4-pentafluorobutane.

16. A composition comprising 2-chloro-1,1,1,4,4,4-hexafluorobutane, 1,1,1,4,4,4-hexafluorobutane, 1,1,1-trifluoro-2-trifluoromethylbutane, Z-1,1,1,4,4,4-hexafluoro-2-chloro-2-butene, E-1,1,1,4,4,4-hexafluoro-2-chloro-2-butene, Z-1,1,1,4,4,4-hexafluoro-2,3-dichlorobutene, and E-1,1,1,4,4,4-hexafluoro-2,3-dichlorobutene.