Processes for producing Z-1,1,1,4,4,4-hexafluorobut-2-ene and intermediates for producing same
Processes for producing Z-1,1,1,4,4,4-hexafluorobut-2-ene and intermediates for producing same. A process for producing 2-chloro-1,1,1,4,4,4-hexafluorobutane comprises contacting 1,1,2,4,4-pentachlorobuta-1,3-diene with HF in the liquid phases. A process for producing E-1,1,1,4,4,4-hexafluorobut-2-ene comprises contacting 2-chloro-1,1,1,4,4,4-hexafluorobutane with base. A process for producing 2,3-dichloro-1,1,1,4,4,4-hexafluorobutane comprises contacting E-1,1,1,4,4,4-hexafluorobut-2-ene with a chlorine source. A process for producing 1,1,1,4,4,4-hexafluoro-2-butyne comprises contacting 2,3-dichloro-1,1,1,4,4,4-hexafluorobutane with a base. A process for producing Z-1,1,1,4,4,4-hexafluorobut-2-ene comprises contacting 1,1,1,4,4,4-hexafluoro-2-butyne with hydrogen and a catalyst.
1. A process to produce Z-1,1,1,4,4,4-hexafluoro-2-butene comprising: (a′) contacting trichloroethylene in the presence of a dimerization catalyst to produce a product mixture comprising 1,1,2,4,4-pentachlorobuta-1,3-diene (HCC-2320az), wherein the dimerization catalyst comprises iron or copper; (a) contacting 1,1,2,4,4-pentachlorobuta-1,3-diene produced in step (a′) with hydrogen fluoride in the liquid phase in the presence of a fluorination catalyst to produce a product mixture comprising 2-chloro-1,1,1,4,4,4-hexafluorobutane (HCFC-346mdf); (b) contacting 2-chloro-1,1,1,4,4,4-hexafluorobutane with base to produce a product mixture comprising E-1,1,1,4,4,4-hexafluoro-2-butene (E-1336mzz); (c) contacting E-1, 1,1,4,4,4-hexafluoro-2-butene with a chlorine source in the presence of a catalyst to produce a product mixture comprising 2,3-dichloro-1,1,1,4,4,4-hexafluorobutane (HCFC-336mdd); (d) contacting 2,3-dichloro-1,1,1,4,4,4-hexafluorobutane with a base to produce a product mixture comprising 1,1,1,4,4,4-hexafluoro-2-butyne; and (e) contacting 1,1,1,4,4,4-hexafluoro-2-butyne with hydrogen to produce a product mixture comprising Z-1,1,1,4,4,4-hexafluoro-2-butene, wherein step (a′) is performed in the presence of pentachloroethane, wherein the weight ratio of pentachlororethane to trichloroethylene is from about 0.001 to about 1.
2. The process of claim 1 , wherein the catalyst in step (a) is a metal halide.
3. The process of claim 1 , wherein steps (b) and (d) are performed in the presence of a phase transfer catalyst.
4. The process of claim 1 , wherein step (c) is performed in the presence of a vapor phase catalyst in the vapor phase.
5. The process of claim 1 , wherein step (c) is performed in the presence of a liquid phase catalyst in the liquid phase.
6. The process of claim 1 , wherein step (c) is performed with photoinitiation.
7. The process of claim 1 , wherein step (e) is performed in the presence of an alkyne-to-alkene catalyst, comprising palladium.
8. The process of claim 1 , further comprising recovering 2-chloro-1,1,1,4,4,4-hexafluorobutane from step (a).
9. The process of claim 1 , further comprising recovering E-1,1,1,4,4,4-hexafluoro-2-butene from step (b).
10. The process of claim 1 , further comprising recovering 2,3-dichloro-1,1,1,4,4,4-hexafluorobutane from step (c).
11. The process of claim 1 , further comprising recovering 1,1,1,4,4,4-hexafluoro-2-butyne from step (d).
12. The process of claim 1 , wherein the temperature of step (a′) is greater than 200° C. and less than 245° C.
13. The process of claim 1 , wherein, following step (a′), the pentachlororethane is recovered and recycled.