Process for cis 1,1,1,4,4,4-hexafluoro-2-butene

1. A process for preparing cis-1,1,1,4,4,4-hexafluorobutene comprising steps:

(a) reacting CCl 4 with a compound having the formula:

CF 3 CX═CXH

where X=halogen or H independent of each other, wherein the compound CF 3 CX═CXH is selected from the group consisting of CF 3 CCl═CClH, CF 3 CH═CHCl, CF 3 CCl═CH 2 , CF 3 CCl═CFH, CF 3 CF═CHCl, CF 3 CF═CFH, CF 3 CH═CFH, CF 3 CF═CH 2 , CF 3 CH═CFH, CF 3 CH═CHBr, CF 3 CBr═CH 2 , CF 3 CBr═CHBr, CF 3 CH═CHI, CF 3 CI═CHI, and CF 3 CI═CH 2 ; to form a compound having the formula:

CF 3 CXClCXHCCl 3

(b) fluorinating the compound formed in step (a) to form a compound having the formula:

CF 3 CXHCXHCF 3

(c) converting the compound formed in step (b) by a reaction selected from the group consisting of dehydrohalogenation, dehalogenation and both reactions, to form a compound having the formula:

CF 3 C≡CCF 3

and

(d) catalytically reducing the compound formed in step (c) with hydrogen to form the compound having the formula:

2. The process of claim 1 , wherein any of the steps can be run in a continuous manner.

3. The process of claim 1 , wherein the compound CF 3 CX═CXH is CF 3 CCl═CHCl.

4. The process of claim 1 , wherein the compound CF 3 CX═CXH is CF 3 CCl═CFH.

5. The process of claim 1 , wherein the compound CF 3 CXClCXHCCl 3 is CF 3 CCl 2 CHClCCl 3 .

6. The process of claim 1 , wherein the compound CF 3 CXClCXHCCl 3 is CF 3 CCl 2 CFHCCl 3 .

7. The process of claim 1 , wherein the step (c) reaction comprises dehydrohalogenation of CF 3 CXHCXHCF 3 .

8. The process of claim 1 , wherein the step (c) reaction comprises dehalogenation of CF 3 CXHCXHCF 3 .

9. The process of claim 1 , wherein the step (c) reaction comprises both dehydrohalogenation and dehalogenation of CF 3 CXHCXHCF 3 .

10. A continuous process for preparing cis-1,1,1,4,4,4-hexafluorobutene comprising steps:

(a) the addition of CCl 4 to CF 3 CCl═CHCl using CuCl 2 and acetonitrile to produce CF 3 CCl 2 CHClCCl 3 ;

(b) the fluorination of CF 3 CCl 2 CHClCCl 3 from step (a) using SbCl 5 and anhydrous HF to produce CF 3 CCl 2 CHClCF 3 ;

(c) the dehydrohalogenation of CF 3 CCl 2 CHClCF 3 from step (b) with KOH and a phase transfer catalyst to produce CF 3 CCl═CClCF 3 ;

(d) the dehalogenation of CF 3 CCl═CClCF 3 from step (d) with Zn dust and acetic anhydride to produce CF 3 C≡CCF 3 ; and

(e) the reduction of CF 3 C≡CCF 3 from step (d) using hydrogen and a catalyst consisting of 5% Pd on CaCO 3 poisoned with 3.5% lead, to produce cis-CF 3 CH═CHCF 3 .