Organic compounds -- part of the class 532-570 series – Organic compounds – Halogen containing
Patent
1996-02-26
1998-06-09
Lambkin, Deborah
Organic compounds -- part of the class 532-570 series
Organic compounds
Halogen containing
570132, 570156, C07C 1700, C07C 1725, C07C 1908
Patent
active
057637032
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/JP94/01285, Aug. 3, 1994.
INDUSTRIAL USES
This invention is concerned with the method of manufacturing hexafluorocyclobutene, a useful compound that can be employed not only as a raw material for detergents and HFC foaming agents which will not deplete the ozone layer, but also a raw material for various resins and serve as an intermediate for medicinal drugs and agricultural chemicals. This invention can also be applied to the method of manufacturing (Z)-1,2,3,3,4,4-hexafluorocyclobutane, a useful compound that can be employed as an alternate to CFCs and HCFCs presently being used as refrigerants, blowing agents and detergents.
CONVENTIONAL TECHNOLOGIES
The method of carrying out the reaction of zinc with 1,2-dichlorohexafluorocyclobutane in alcohol to obtain hexafluorocyclobutene is well known (G. Fuller and J. C. Tatlow, J. Chem Soc., 3198 (1961)).
The reaction, however, requires a large quantity of solvent and also involves enormous costs for processing zinc chloride produced by the reaction. Therefore, the process cannot be considered effective for industrial use.
The method for reducing 1,2-dichlorohexafluorocyclobutane using lithium aluminum hydride (LiAlH.sub.4), is known as the (Z)-1,2,3,3,4,4-hexafluorocyclobutane manufacturing method (also described in the above-mentioned document).
However, the yield of (Z)-1,2,3,3,4,4-hexafluorocyclobutane using this common method is low as being a 30% yield. The method also produces a large quantity of the geometrical isomer of the target compound, (E)-1,2,3,3,4,4-hexafluorocyclobutane, as a by-product. Therefore, this method is not suitable for industrial use. In this paper, (Z) refers to "Zusammen" which corresponds to the "cis" form; and (E) refers to "Entgegen" which corresponds to the "trans" form.
PURPOSES OF THE INVENTION
One purpose of this invention is to provide an easy and inexpensive method with high selectivity of hexafluorocyclobutene from 1,2-dichlorohexafluorocyclobutane.
Another purpose of the invention is to provide a high-yield method for manufacturing (Z)-1,2,3,3,4,4-hexafluorocyclobutane employing the hexafluorocyclobutene reduction reaction.
An additional purpose of this invention is to provide a high-yield method for manufacturing (Z)-1,2,3,3,4,4-hexafluorocyclobutane employing the 1,2-dichlorohexafluorocyclobutane reduction reaction.
CONSTRUCTION OF THE INVENTION
The inventors have conducted a thorough study of the processes for the efficient, low-cost manufacturing of hexafluorocyclobutene. As a result of the study, the inventors have perfected a process for high-selectively manufacturing hexafluorocyclobutene from 1,2-dichlorohexafluorocyclobutane available at low cost.
The invention is concerned with the method of manufacturing hexafluorocyclobutene, an intermediate for synthesis of (Z)-1,2,3,3,4,4-hexafluorocyclobutane, by dechlorinating 1,2-dichlorohexafluorocyclobutane using hydrogen in the presence of a catalyst consisting of metal oxide and/or silicon oxide, the metal oxide comprising at least one or plural kinds of metal selected from iron, chromium, cobalt, copper, nickel and manganese.
In the manufacturing process carried out according to the invention, the raw material, 1,2-dichlorohexafluorocyclobutane, is easily available by dimerizing 1,2,2-trifluoro-1-chloroethylene.
In addition, the metal oxide used as a catalyst in the reductive dehalogenation (dechlorination) of 1,2-dichlorohexafluorocyclobutane, can be obtained by calcinating the metal hydroxide sediment produced by the conventional method in which an alkali such as ammonia solution or alkaline metal hydroxide is added to chloride, sulfate, or nitrate solution of Cr, Fe, Co, Cu, Ni or Mn. Each of the metal oxides can be used alone. Moreover, compound oxide or mixed oxide of multiple metals selected from those above mentioned can be used as a catalyst for the reaction.
The catalyst can be granulated or compressed into a pellet shape. The oxide can be supported on a suitable carrier which is not directly involved in the rea
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Aoyama Hirokazu
Nakada Tatsuo
Yamamoto Akinori
Daikin Industries Ltd.
Lambkin Deborah
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