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 alkynes 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 gas phase in the presence of a catalyst at a temperature sufficient to cause elimination of the chlorine substituents of the chlorofluoroalkene to produce a fluorine-containing alkyne, having the formula R 1 C≡CR 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 said catalyst is a composition comprising copper, nickel and chromium.
2. The process of claim 1 wherein said catalyst is supported on calcium fluoride.
3. The process of claim 2 wherein the molar ratio of copper:nickel:chromium in the copper/nickel/chromium on calcium fluoride catalyst is 1 copper:about 1 to about 6 nickel, and about 0.25 to about 4 chromium.
4. The process of claim 1 wherein each R f is CF 3 .
5. The process of claim 1 wherein each of R 1 and R 2 is CF 3 .
6. The process of claim 1 wherein the process is conducted at a temperature of from about 350° C. to about 450° C.
7. The process of claim 1 wherein the ratio of hydrogen to chlorofluoroalkene is from about 2:1 to about 6:1.
8. The process of claim 1 wherein the ratio of hydrogen to chlorofluoroalkene is from about 2:1 to about 4:1.
9. The process of claim 1 wherein the ratio of hydrogen to chlorofluoroalkene is about 2:1.
10. The process of claim 2 wherein the molar ratio of copper:nickel:chromium in the copper/nickel/chromium on calcium fluoride catalyst is 1 copper:about 1 to about 3.0 nickel, and about 0.25 to about 1 chromium.
11. The process of claim 2 wherein the molar ratio of copper:nickel:chromium in the copper/nickel/chromium on calcium fluoride catalyst is 1 copper:about 1 to about 2 nickel, and about 0.5 to about 1 chromium.