Process for making 1,3,3,3-tetrafluoropropene
View Patent ↗The present invention describes a process for making CF 3 CH═CHF (HFO-1234ze). The process involves the addition of carbon tetrachloride (CCl 4 ) to 1,2-dichloroethylene to form CCl 3 CHClCHCl 2 . The compound CCl 3 CHClCHCl 2 thus can then either be treated with HF to produce CF 3 CHClCHClF as the main product, or it can be converted to CCl 2 ═CHCHCl 2 (1230za) by dechlorination. CCl 2 ═CHCHCl 2 can be treated with HF such that the main product obtained is CF 3 CHClCHClF. CF 3 CH═CHCl may be produced as a by-product, but upon treatment with HF, it affords the compound CF 3 CHClCHClF. The desired compound, CF 3 CH═CHF (HFO-1234ze), is obtained as a trans/cis mixture by dehydrochlorination of CF 3 CH 2 CHClF or by dechlorination of CF 3 CHClCHClF.
1. A process for making CF 3 CH═CHF comprising the steps of:
(a) converting 1,2-dichloroethylene to the compound CCl 3 CHClCHCl 2 by an addition reaction with CCl 4 ;
(b) converting CCl 3 CHClCHCl 2 to the compound CCl 2 ═CHCHCl 2 by a dechlorination reaction;
(c) fluorinating the product of step (b) to form the compound CF 3 CH 2 CHClF; and
(d) dehydrochlorinating the product of step (c) to form the compound CF 3 CH═CHF.
2. The process of claim 1 , wherein the reaction of step (a) is conducted with a catalyst.
3. The process of claim 2 , wherein the catalyst comprises a copper catalyst.
4. The process of claim 2 , wherein the catalyst comprises a ruthenium catalyst.
5. The process of claim 1 , wherein the dechlorination reaction of step (b) is conducted using zinc.
6. The process of claim 1 , wherein the fluorination reaction of step (c) is conducted with hydrogen fluoride and a fluorination catalyst.
7. The process of claim 6 , wherein the hydrogen fluoride is anhydrous.
8. The process of claim 6 , wherein the fluorination catalyst has the formula SbCl x F y , where x+y=5.
9. The process of claim 6 , wherein the fluorination catalyst comprises SbCl 5 .
10. The process of claim 6 , wherein the fluorination catalyst comprises SbF 5 .
11. The process of claim 6 , wherein the fluorination catalyst is supported on activated carbon.
12. The process of claim 1 , wherein the dehydrochlorination reaction of step (d) is conducted in either the liquid phase or the gas phase, with a dehydrochlorination catalyst.
13. The process of claim 12 , wherein the dehydrochlorination reaction is conducted in the liquid phase.
14. The process of claim 13 , wherein the catalyst comprises an alkali metal hydroxide with a phase transfer catalyst.
15. The process of claim 14 , wherein the alkali metal hydroxide comprises sodium hydroxide.
16. The process of claim 14 , wherein the alkali metal hydroxide comprises potassium hydroxide.
17. The process of claim 12 , wherein the dehydrochlorination reaction is conducted in the gas phase.
18. The process of claim 17 , wherein the catalyst comprises acid treated activated carbon.
19. The process of claim 18 , wherein the acid treatment is selected from HCl and HNO 3 .
20. The process of claim 17 , wherein the dehydrochlorination reaction is conducted at a temperature range of from about 300° C. to 500° C.
21. The process of claim 17 , wherein the dehydrochlorination reaction is conducted at a temperature range of from about 350° C. to 370° C.
22. A process for making CF 3 CH═CHF comprising the steps of:
(a) reacting carbon tetrachloride with 1,2-dichloroethylene to form the compound CCl 3 CHClCHCl 2 ;
(b) fluorinating the compound CCl 3 CHClCHCl 2 with HF to produce the compound CF 3 CHClCHClF; and
(c) dechlorinating CF 3 CHClCHClF to produce the compound CF 3 CH═CHF.
23. The process of claim 22 , wherein the dechlorination reaction is conducted with zinc.
24. The process of claim 22 , wherein a portion of the compound CCl 3 CHClCHCl 2 is converted to the compound CCl 2 =CHCHCl 2 (HCC-1230za) by a dechlorination reaction.
25. The process of claim 22 , wherein a portion of the compound CCl 3 CHClCHCl 2 is fluorinated with HF and a fluorination catalyst to afford the compound CF 3 CHClCHClF.
26. The process of claim 25 , wherein the fluorination catalyst has the formula SbCl x F y , where x+y=5.
27. The process of claim 26 , wherein the fluorination catalyst comprises SbCl 5 .
28. The process of claim 26 , wherein the fluorination catalyst comprises SbF 5 .
29. The process of claim 26 , wherein the fluorination catalyst is supported on activated carbon.
30. The process of claim 24 , further comprising the step wherein the compound CCl 2 ═CHCHCl 2 is fluorinated with HF and a fluorination catalyst to produce the compound CF 3 CHClCHClF.
31. The process of claim 30 , further comprising the step wherein the dechlorination of CF 3 CHClCHClF affords the compound CF 3 CH═HF (HFO-1234ze).
32. The process of claim 22 , wherein the dechlorination reaction also produces the compound CF 3 CH═CHCl as a by-product.
33. The process of claim 32 , further comprising the step wherein the by-product compound CF 3 CH═CHCl is fluorinated with hydrogen fluoride and a fluorination catalyst to produce the compound CF 3 CHClCHClF.
34. The process of claim 1 , wherein the reactions are conducted in a continuous manner.
35. The process of claim 22 , wherein the reactions are conducted in a continuous manner.