Integrated process for the production of Z-1,1,1,4,4,4-hexafluoro-2-butene
Disclosed is a process for the preparation of cis-1,1,1,4,4,4-hexafluoro-2-butene comprising contacting 1,1,1-trifluorotrichloroethane with hydrogen in the presence of a catalyst comprising ruthenium to produce a product mixture comprising 1316mxx, recovering said 1316mxx as a mixture of Z- and E-isomers, contacting said 1316mxx with hydrogen, in the presence of a catalyst selected from the group consisting of copper on carbon, nickel on carbon, copper and nickel on carbon and copper and palladium on carbon, to produce a second product mixture, comprising E- or Z-CFC-1326mxz, and subjecting said second product mixture to a separation step to provide E- or Z-1326mxz. The E- or Z-1326mxz can be dehydrochlorinated in an aqueous basic solution with an alkali metal hydroxide in the presence of a phase transfer catalyst to produce hexafluoro-2-butyne, which can then be selectively hydrogenated to produce Z-1,1,1,4,4,4-hexafluoro-2-butene using either Lindlar's catalyst, or a palladium catalyst further comprising a lantanide element or silver.
1. A process for coupling a chlorofluorocarbon comprising: contacting 1,1,1-trichloro-2,2,2-trifluoroethane with hydrogen in the presence of a catalyst comprising ruthenium on a silicon carbide support, to produce a product mixture comprising 1,1,1,4,4,4-hexafluoro-2,3-dichloro-2-butene and hydrogen chloride, and recovering the 1,1,1,4,4,4-hexafluoro-2,3-dichloro-2-butene.
2. The process of claim 1 , wherein said product mixture comprises less than 4 parts per hundred by weight of 2 carbon by-products.
3. The process of claim 2 , wherein said 2 carbon by-products are at least one of 2,2-dichloro-1,1,1-trifluoroethane, 2-chloro-1,1,1-trifluoroethane and 1,1,1-trifluoroethane.
4. The process of claim 1 further comprising the dispersion of said ruthenium on said silicon carbide support is less than 3 m 2 /gm.
5. The process of claim 1 , wherein said ruthenium is present on the silicon carbide support at a loading of between 0.5% and 3% by weight.
6. The process of claim 1 , wherein said hydrogen chloride produced comprises less than 1 percent by weight hydrogen fluoride.
7. The process of claim 1 , wherein the reaction is conducted at a temperature of from 150° C. to 190° C.