Method for preparing halogenated butene and butane

Details Method for preparing halogenated butene and butane Method for preparing halogenated butene and butane

1993-09-03

1999-07-06

Siegel, Alan

Organic compounds -- part of the class 532-570 series

Organic compounds

Halogen containing

570166, 570168, C07C 1720, C07C 1708

Patent

active

059199938

DESCRIPTION:

BRIEF SUMMARY
BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates to a method for preparing halogenated butene and butane. Particularly, it relates to a method for preparing at least one halogenated compound selected from the group consisting of 1,1,1,4,4,4-hexafluoro-2,3-dichlorobutane, 1,1,1,4,4,4-hexafluoro-2-chloro-2-butene, 1,1,1,2,4,4,4-heptafluoro-2-butene and 1,1,1,2,2,4,4,4-octafluorobutane.
2. Related Art
1,1,1,4,4,4-Hexafluoro-2,3-dichlorobutane, 1,1,1,4,4,4-hexafluoro-2-chloro-2-butene and 1,1,1,2,4,4,4-heptafluoro-2-butene are useful as industrial chemicals and as an intermediate for medicines and agricultural chemicals. In addition, these materials can be a raw material to prepare 1,1,1,2,2,4,4,4-octafluorobutane which can be prepared by adding hydrogen fluoride (HF) to these materials, and which substitutes for HCFC and is used as a foaming agent, a detergent and a heating medium. 1,1,1,4,4,4-Hexafluoro-2,3-dichlorobutane, 1,1,1,4,4,4-hexafluoro-2-chloro-2-butene and 1,1,1,2,4,4,4-heptafluoro-2-butene can be reduced to prepare 1,1,1,4,4,4-hexafluoro-butane which is used as the same applications as those of these materials.
It is known that 1,1,1,2,4,4,4-heptafluorobutene can be prepared by fluorinating hexachlorobutadiene with KF. However, this method is commercially unsuitable, since a reaction procedure is complex, a treatment of KC1 produced after the reaction is necessary due to the use of KF, and a cost is high.
It is also known that 1,1,1,4,4,4-hexafluoro-2-chloro-2-butene can be prepared by fluorinating hexachloro-1,3-butadiene with HF in the presence of SbCl.sub.5. However, the antimony catalyst is highly corrosive so that this method is not practically useful due to the absence of a material suitable for a reactor. It is not known to commercially prepare 1,1,1,4,4,4-hexafluoro-2,3-dichlorobutane and 1,1,1,2,2,4,4,4-octafluorobutane.


SUMMARY OF THE INVENTION

An object of the present invention is to provide a commercially useful method for preparing 1,1,1,4,4,4-hexafluoro-2,3-dichlorobutane, 1,1,1,4,4,4-hexafluoro-2-chloro-2-butene, 1,1,1,2,4,4,4-heptafluoro-2-butene and 1,1,1,2,2,4,4,4-octafluorobutane, which has not been found yet.
The invention intensively studied ways to obtain a commercially useful method for preparing 1,1,1,4,4,4-hexafluoro-2,3-dichlorobutane, 1,1,1,4,4,4-hexafluoro-2-chloro-2-butene, 1,1,1,2,4,4,4-heptafluoro-2-butene and 1,1,1,2,2,4,4,4-octafluorobutane, found that these halogenated compounds can be prepared by selecting a suitable catalyst in the gas phase fluorination of easily available 1,1,2,3,4,4-hexachloro-1,3-butadiene, and then completed the present invention.
Namely, the present invention provides a method for preparing at least one halogenated compound selected from the group consisting of 1,1,1,4,4,4-hexafluoro-2,3-dichlorobutane, 1,1,1,4,4,4-hexafluoro-2-chloro-2-butene, 1,1,1,2,4,4,4-heptafluoro-2-butene and 1,1,1,2,2,4,4,4-octafluorobutane, which comprises reacting 1,1,2,3,4,4-hexachloro-1,3-butadiene with hydrogen fluoride in a gas phase in the presence of a fluorinating catalyst.


DETAILED EXPLANATION OF THE INVENTION

The raw material 1,1,2,3,4,4-hexachloro-1,3-butadiene can be economically prepared by chlorinating butane.
The catalyst may be a metal fluoride or a metal oxyfluoride. The metal fluoride and the metal oxyfluoride can be prepared, for example, by adding an alkali to a solution of a metal salt to precipitate a metal oxide and then fluorinating the metal oxide with HF. Specific examples of the metal salt are a chloride, a nitrate salt, a sulfate salt and the like. Specific examples of the alkali are ammonia, urea, an alkaline metal hydroxide and the like.
Specific examples of the metal are one metal or a mixture selected from the group consisting of aluminum, chromium, manganese, nickel and cobalt.
The metal fluoride and the metal oxyfluoride can be used with or without supported on a suitable carrier. Specific examples of the suitable carrier are active carbon, aluminum fluoride and the like.
The reaction is

REFERENCES:
patent: 3965201 (1976-06-01), Minklei
patent: 4147733 (1979-04-01), Fiske et al.
patent: 5146019 (1992-09-01), Bielefeldt et al.
patent: 5233105 (1993-08-01), Schwarz et al.

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