Catalytic isomerization of Z-1,1,1,4,4,4-hexafluoro-2-butene to E-1,1,1,4,4,4-hexafluoro-2-butene

1. A process for isomerizing Z-1,1,1,4,4,4-hexafluoro-2-butene to E-1,1,1,4,4,4-hexafluoro-2-butene comprising:

(a) providing a starting material comprising Z-1,1,1,4,4,4-hexafluoro-2-butene;

(b) contacting the starting material with a suitable catalyst in a reaction zone to produce E-HFO-1336mzz; and optionally,

(c) recovering the E-HFO-1336mzz,

wherein, when the contacting step is performed in the gas phase, the catalyst comprises chromium and less than 40% by weight alumina;

wherein when the contacting step is performed in the liquid phase, the catalyst comprises a metal halide wherein the metal halide is aluminum halide, antimony halide, tin halide, tantalum halide, titanium halide, niobium halide, molybdenum halide, iron halide, fluorinated chrome halide, or combinations thereof.

2. The process of claim 1 wherein the contacting step is performed in the gas phase.

3. The process of claim 1 wherein the contacting step is performed in the liquid phase.

4. The process of claim 1 further comprising recovering the E-HFO-1336mzz.

5. The process of claim 1 wherein a suitable catalyst comprises chromium oxyfluoride.

6. The process of claim 1 wherein a suitable catalyst contains SbCl 5 , SbCl 3 , SbF 5 , SnCl 4 , TaCl 5 , TiCl 4 , NbCl 5 , MoCl 6 , FeCl 3 , a fluorinated species of SbCl 5 , a fluorinated species of SbCl 3 , a fluorinated species of SnCl 4 , a fluorinated species of TaCl 5 , a fluorinated species of TiCl 4 , a fluorinated species of NbCl 5 , a fluorinated species of MoCl 6 , a fluorinated species of FeCl 3 , or combinations thereof.

7. The process of claim 6 wherein a suitable catalyst contains MCl 5-n F n , wherein M=Sb or Ta and n=0-5.

8. The process of claim 7 wherein the catalyst is antimony pentafluoride.

9. The process of claim 7 wherein the catalyst is tantalum pentafluoride.

10. The process of claim 6 wherein a suitable catalyst contains AlZ 3 , wherein Z is one or more of Br, F or Cl, provided that Z cannot be entirely F.

11. The process of claim 10 wherein AlZ 3 has the formula AlCl x F y , where the total number of atoms of halide, x plus y equals 3, where x ranges from about 0.05 to 2.95 and y ranges from about 2.95 to 0.05.

12. The process of claim 2 wherein the temperature in the reaction zone is in the range from about 100° C. to about 500° C.

13. The process of claim 12 wherein the temperature in the reaction zone is in the range from about 150° C. to about 400° C.

14. The process of claim 13 wherein the temperature in the reaction zone is in the range from about 250° C. to about 300° C.

15. The process of claim 3 wherein the temperature in the reaction zone is in the range of −20° C. to about 150° C.

16. The process of claim 15 wherein the temperature in the reaction zone is in the range of from about 50° C. to about 150° C.

17. The process of claim 16 wherein the temperature in the reaction zone is in the range of from about from about 100° C. to about 130° C.

18. The process of claim 1 wherein the process is a batch process.

19. The process of claim 1 wherein the process is a continuous process.

20. The process of claim 2 wherein the process is a batch process.

21. The process of claim 2 wherein the process is a continuous process.

22. The process of claim 3 wherein the process is a batch process.

23. The process of claim 3 wherein the process is a continuous process.

24. The process of claim 1 wherein the starting material comprises Z-1336mzz and E-1336mmzz.

25. The process of claim 1 wherein the yield of E-1336mzz is at least 90 mole %.

26. The process of claim 1 wherein the yield of E-1336mzz is at least 95 mole %.

27. The process of claim 1 wherein the yield of E-1336mzz is at least 99 mole %.

28. The process of claim 1 wherein there is unreacted Z-1336mzz in the product, and wherein such unreacted Z-1336mzz is separated from the product and recycled to the reaction zone.