A halogenated alkene compound and a fluorinated alkyne compound are obtained at a high conversion rate and high selectivity by employing any of the following methods (1) to (4): (1) a halogenated butane compound represented by CX.sup.1X.sup.2X.sup.3CHX.sup.4CFHCX.sup.5X.sup.6X.sup.7, wherein X.sup.1, X.sup.2, X.sup.3, X.sup.4, X.sup.5, X.sup.6, and X.sup.7 are the same or different and each is a halogen atom, to a dehydrofluorination reaction; (2) a halogenated butene compound represented by CX.sup.1X.sup.2X.sup.3CX.sup.4═CHCX.sup.5X.sup.6X.sup.7, wherein X.sup.1, X.sup.2, X.sup.3, X.sup.4, X.sup.5, X.sup.6, and X.sup.7 are as defined above, to a dehydrohalogenation reaction; (3) a halogenated alkane compound represented by CHX.sup.8A.sup.1CHX.sup.9A.sup.2, wherein A.sup.1 and A.sup.2 are each a fluorine atom or a perfluoroalkyl group, and X.sup.8 and X.sup.9 are the same or different and each is a halogen atom, to a dehydrohalogenation reaction in the presence of a catalyst in a gas phase; and (4) a halogenated alkene compound represented by CX.sup.8A.sup.1=CHA.sup.2, wherein A.sup.1, A.sup.2, and X.sup.8 are as defined above, to a dehydrohalogenation reaction in the presence of a catalyst.

A process for producing Z-1,1,1,4,4,4-hexafluorobut-2-ene comprises contacting 1,1,2,4,4-pentachlorobuta-1,3-diene with hydrogen fluoride in the vapor phase in the presence of a fluorination catalyst comprising a metal halide to produce E- and Z-1,1,1,4,4,4-hexafluoro-2-chloro-2-butene. A process for producing Z-1,1,1,4,4,4-hexafluorobut-2-ene further comprises contacting E- and Z-1,1,1,4,4,4-hexafluoro-2-chloro-2-butene with base to produce 1,1,1,4,4,4-hexafluoro-2-butyne, and subsequently hydrogenating hexafluoro-2-butyne to produce Z-1,1,1,4,4,4-hexafluoro-2-butene.

A process for producing Z-1,1,1,4,4,4-hexafluorobut-2-ene comprises contacting 1,1,2,4,4-pentachlorobuta-1,3-diene with hydrogen fluoride in the vapor phase in the presence of a fluorination catalyst comprising a metal halide to produce E- and Z-1,1,1,4,4,4-hexafluoro-2-chloro-2-butene. A process for producing Z-1,1,1,4,4,4-hexafluorobut-2-ene further comprises contacting E- and Z-1,1,1,4,4,4-hexafluoro-2-chloro-2-butene with base to produce 1,1,1,4,4,4-hexafluoro-2-butyne, and subsequently hydrogenating hexafluoro-2-butyne to produce Z-1,1,1,4,4,4-hexafluoro-2-butene.

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 phase in the presence of a fluorination catalyst. A process for producing 2,2-dichloro-1,1,1,4,4,4-hexafluorobutane comprises contacting 2-chloro-1,1,1,4,4,4-hexafluorobutane with a chlorine source. A process for producing 1,1,1,4,4,4-hexafluoro-2-butyne comprises contacting 2,2-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.

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 phase in the presence of a fluorination catalyst. A process for producing 2,2-dichloro-1,1,1,4,4,4-hexafluorobutane comprises contacting 2-chloro-1,1,1,4,4,4-hexafluorobutane with a chlorine source. A process for producing 1,1,1,4,4,4-hexafluoro-2-butyne comprises contacting 2,2-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.

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.

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.

A process for producing E-1,1,1,4,4,4-hexafluorobut-2-ene comprises contacting 1,1,2,4,4-pentachlorobuta-1,3-diene with hydrogen fluoride in the vapor phase in the presence of a fluorination catalyst. A process for producing Z-1,1,1,4,4,4-hexafluorobut-2-ene further comprises contacting E-1,1,1,4,4,4-hexafluoro-2-butene with chlorine in the presence of a catalyst to produce 2,3-dichloro-1,1,1,4,4,4-hexafluorobutane, followed by reaction with base to produce 1,1,1,4,4,4-hexafluoro-2-butyne, and subsequently hydrogenating hexafluoro-2-butyne to produce Z-1,1,1,4,4,4-hexafluoro-2-butene.

A process for producing E-1,1,1,4,4,4-hexafluorobut-2-ene comprises contacting 1,1,2,4,4-pentachlorobuta-1,3-diene with hydrogen fluoride in the vapor phase in the presence of a fluorination catalyst. A process for producing Z-1,1,1,4,4,4-hexafluorobut-2-ene further comprises contacting E-1,1,1,4,4,4-hexafluoro-2-butene with chlorine in the presence of a catalyst to produce 2,3-dichloro-1,1,1,4,4,4-hexafluorobutane, followed by reaction with base to produce 1,1,1,4,4,4-hexafluoro-2-butyne, and subsequently hydrogenating hexafluoro-2-butyne to produce Z-1,1,1,4,4,4-hexafluoro-2-butene.

A halogenated alkene compound and a fluorinated alkyne compound are obtained at a high conversion rate and high selectivity by employing any of the following methods (1) to (4): (1) a halogenated butane compound represented by CX.sup.1X.sup.2X.sup.3CHX.sup.4CFHCX.sup.5X.sup.6X.sup.7, wherein X.sup.1, X.sup.2, X.sup.3, X.sup.4, X.sup.5, X.sup.6, and X.sup.7 are the same or different and each is a halogen atom, to a dehydrofluorination reaction; (2) a halogenated butene compound represented by CX.sup.1X.sup.2X.sup.3CX.sup.4═CHCX.sup.5X.sup.6X.sup.7, wherein X.sup.1, X.sup.2, X.sup.3, X.sup.4, X.sup.5, X.sup.6, and X.sup.7 are as defined above, to a dehydrohalogenation reaction; (3) a halogenated alkane compound represented by CHX.sup.8A.sup.1CHX.sup.9A.sup.2, wherein A.sup.1 and A.sup.2 are each a fluorine atom or a perfluoroalkyl group, and X.sup.8 and X.sup.9 are the same or different and each is a halogen atom, to a dehydrohalogenation reaction in the presence of a catalyst in a gas phase; and (4) a halogenated alkene compound represented by CX.sup.8A.sup.1=CHA.sup.2, wherein A.sup.1, A.sup.2, and X.sup.8 are as defined above, to a dehydrohalogenation reaction in the presence of a catalyst.