Integrated process for the production of Z-1,1,1,4,4,4-hexafluoro-2-butene
View Patent ↗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 using either Lindlar's catalyst, or a palladium catalyst further comprising a lantanide element or silver.
1. A process for the preparation of cis-1,1,1,4,4,4-hexafluoro-2-butene comprising:
a) contacting 1,1,1-trifluorotrichloroethane with hydrogen in the presence of a catalyst comprising ruthenium to produce a product mixture comprising 1316mxx;
b) recovering said 1316mxx as a mixture of Z- and E-isomers;
c) 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;
d) subjecting said second product mixture to a separation step to provide E- or Z-1326mxz; and
e) further comprising contacting said E- or Z-CFC1326mxz with an aqueous solution of an alkali metal hydroxide in the presence of a phase transfer catalyst to produce hexafluoro-2-butyne; and;
f) further comprising contacting said hexafluoro-2-butyne with hydrogen in the presence of a catalyst of palladium on a support, and at least one element selected from the group consisting of lanthanum, cerium and silver, to produce cis-1,1,1,4,4,4-hexafluoro-2-butene.
2. The process of claim 1 , wherein step e) comprises further contacting said E- or Z-1326mxz with an aqueous solution of an alkali metal hydroxide in the presence of a quaternary alkylammonium salt having alkyl groups of from four to twelve carbon atoms and mixtures thereof, wherein at least said Z-1326mxz is converted to produce a mixture comprising hexafluoro-2-butyne, and recovering the hexafluoro-2-butyne.
3. The process of claim 1 , wherein step e) comprises further contacting said E- or Z-1326mxz with an aqueous solution of an alkali metal hydroxide in the presence of a quaternary alkylammonium salt which comprises at least one alkyl group of at least 8 carbons, wherein at least said E-1326mxz is converted to produce a mixture comprising hexafluoro-2-butyne, and recovering the hexafluoro-2-butyne.
4. The process of claim 2 or 3 , wherein the alkali metal hydroxide further comprises an alkali metal halide.
5. The process of claim 1 , wherein the catalyst for the first contacting step is ruthenium supported on calcium fluoride or ruthenium supported on silicon carbide.
6. A process for the preparation of fluorine-containing olefins comprising contacting a chlorofluoroalkene having the formula E- and Z-CF 3 CCl═CClCF 3 with hydrogen in the presence of a catalyst comprising copper and palladium on a support, at a temperature of from about 150° C. to 250° C., to produce a product mixture comprising a fluorine-containing olefin having the formula E- or Z-CF 3 CH═CClCF 3 , or a mixture thereof, wherein the conversion of Z-CF 3 CCl═CClCF 3 is at least 80% of the conversion of the E-isomer, and the selectivity to the two isomers of CF 3 CH═CClCF 3 is at least 85%.
7. The process of claim 6 , wherein said support is carbon.
8. The process of claim 6 , wherein the process is conducted at a temperature of from 175° C. to 250° C.
9. The process of claim 6 , wherein the ratio of hydrogen to E- or Z-CF 3 CCl═CClCF 3 1:1 to 8:1.
10. The process of claim 6 , wherein the ratio of hydrogen to E- or Z-CF 3 CCl═CClCF 3 1:1 to 2:1.
11. The process of claim 6 , wherein the selectivity for the production of E- or Z-CF 3 CH═CClCF 3 is at least 90%.
12. The process of claim 6 , wherein the selectivity for the production of E- or Z-CF 3 CH═CClCF 3 is at least 95%.