Method of hydrodechlorination to produce dihydrofluorinated olefins
View Patent ↗Disclosed herein is a process for the preparation of fluorine-containing olefins comprising contacting a chlorofluoroalkene with hydrogen in the presence of a catalyst at a temperature sufficient to cause replacement of the chlorine substituents with hydrogen. Also disclosed is a catalyst composition for the hydrodechlorination of chlorofluoroalkenes comprising copper metal deposited on a support.
1. A process for the preparation of fluorine-containing olefins comprising contacting a chlorofluoroalkene having the formula R f CCl═CClR f wherein each R f is a perfluoroalkyl group independently selected from the group consisting of CF 3 , C 2 F 5 , n-C 3 F 7 , i-C 3 F 7 , n-C 4 F 9 , i-C 4 F 9 and t-C 4 F 9 , and wherein one of the R f groups may be F with hydrogen in the presence of a catalyst at a temperature sufficient to cause replacement of the chlorine substituents of the chlorofluoroalkene with hydrogen to produce a product mixture comprising a fluorine-containing olefin having the formula E- or Z—R 1 CH═CHR 2 , and optionally, a chlorofluoroolefin having the formula E- or Z—R 1 CCl═CHR 2 , wherein each of R 1 and R 2 are, perfluoroalkyl groups independently selected from the group consisting of CF 3 , C 2 F 5 , n-C 3 F 7 , i-C 3 F 7 , n-C 4 F 9 , i-C 4 F 9 and t-C 4 F 9 , and wherein R 2 may be F, wherein the catalyst selected from the group consisting of copper on carbon, copper on calcium fluoride, palladium on barium sulfate, palladium/barium chloride on alumina, Lindlar catalyst (palladium on CaCO 3 , poisoned with lead), palladium on calcium fluoride poisoned with lead, copper and nickel on carbon, nickel on carbon, nickel on calcium fluoride, copper/nickel/chromium on calcium fluoride and unsupported alloys of copper and nickel.
2. The process of claim 1 wherein said catalyst is selected from the group consisting of copper on carbon, copper on calcium fluoride, palladium on barium sulfate, palladium/barium chloride on alumina, Lindlar catalyst (palladium on CaCO 3 , poisoned with lead), palladium on calcium fluoride poisoned with lead, copper and nickel on carbon, nickel on carbon, nickel on calcium fluoride, copper/nickel/chromium on calcium fluoride and unsupported alloys of copper and nickel.
3. The process of claim 1 wherein the said catalyst is selected from the group consisting of copper on carbon, copper on calcium fluoride, copper and nickel on carbon, nickel on carbon, copper/nickel/chromium on calcium fluoride and unsupported alloys of copper and nickel.
4. The process of claim 1 wherein each R f is CF 3 .
5. The process of claim 1 wherein each R f is n-C 3 F 7 .
6. The process of claim 1 wherein each of R 1 and R 2 is CF 3 .
7. The process of claim 1 wherein each of R 1 and R 2 is n-C 3 F 7 .
8. The process of claim 1 wherein the process is conducted at a temperature of from about 200° C. to about 450° C.
9. The process of claim 1 wherein the ratio of hydrogen to chlorofluoroalkene is from about 1:1 to about 10:1.
10. The process of claim 1 wherein the ratio of hydrogen to chlorofluoroalkene is from about 1:1 to about 7.5:1.
11. The process of claim 3 wherein the molar ratio of copper:nickel:chromium in the copper/nickel/chromium on calcium fluoride catalyst is about 0 to about 1 copper:about 0.5 to about 3.0 nickel, and about 0 to about 2 chromium.
12. The process of claim 3 wherein the amount of copper on carbon or calcium fluoride is from about 1% to about 25% by weight.
13. The process of claim 3 wherein the amount of copper on carbon or calcium fluoride is from about 5% to about 25% by weight.
14. The process of claim 1, wherein each R f is CF 3 and the product mixture further comprises E and/or Z-2-chloro-1,1,1,4,4,4-hexafluoro-2-butene.
15. The process of claim 1, wherein each R f is CF 3 and the product mixture further comprises Z-2-chloro-1,1,1,4,4,4-hexafluoro-2-butene.