Organic compounds -- part of the class 532-570 series – Organic compounds – Halogen containing
Patent
1995-12-08
1998-02-03
Wu, Shean C.
Organic compounds -- part of the class 532-570 series
Organic compounds
Halogen containing
570124, 570134, 570135, 570136, 570175, 570176, C07C 1908, C07C 2118, C07C 17354
Patent
active
057146543
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/JP94/00865 filed May 30, 1994.
INDUSTRIAL USE
This invention relates to a method of producing a Useful compound of 1,1,1,3,3-pentafluoropropane which can be substituted for CFCs and HCFCs which are used as refrigerants, blowing agents and cleaning agents, and/or producing 1,1,3,3,3-pentafluoropropene which can be easily changed to 1,1,1,3,3-pentafluoropropane by hydrogenation and which is useful as an intermediate in the production of other fluorine-containing organic compounds as well as a monomer to produce high molecular compounds.
PRIOR ART
As a production method of 1,1,1,3,3-pentafluoropropane, it is known that 2,2,3-trichloro-1,1,1,3,3-pentafluoropropane is reduced by hydrogen by using a palladium catalyst (U.S. Pat. No. 2,942,036).
The known method, however, is not suitable for producing 1,1,1,3,3-pentafluoropane industrially because the yield of the product is low due to the formation of a large amount of 1,1,3,3,3-pentafluoropropene and 2-chloro-1,1,3,3,3-pentafluoropropene as byproducts.
Another method is also known in which 1,1,3,3,3-pentafluoropropene is reduced by hydrogen at room temperature by using a palladium catalyst carried on alumina (Bull. Acad. Sol. USSR Div. Chem. Sci. (Eng. Transl.) 1312 (1960)).
In this known method, however, the yield of the target product of 1,1,1,3,3-pentafluoropropane is as low as about 70 percent.
1,1,3,3,3-pentafluoropropene is a useful compound which can be used as a raw material in producing various kinds of resins and as an intermediate in producing some medicines or agricultural chemicals, as well as a raw material of HFC blowing agents which do not destroy the ozone layer.
So far it is known that 1,1,3,3,3-pentafluoropropene can be synthesized by dehydrochlorination of 1,1,1,3,3-pentafluoro-3-chloropropane with a base (J. Am. Chem. Soc., 68 496(1946)).
In this known reaction, however, it is difficult to obtain the raw material and there are many problems in using the reaction industrially as a synthetic method of producing 1,1,3,3,3-pentafluoropropene.
Further, there is a known method of using decarboxylation of a potassium salt of .alpha.-hydroperfluoroisobythylate. In this method, however, it is difficult to obtain the raw material and it is difficult to use the decarboxylation reaction itself industrially (Synthesis of Fluoroorganic Compounds, I. L. Knunyants and G. G. Yakobson, Springer-Verlag, Berlin, Heidelberg, p.8 (1985)).
Besides, there is also a known method of using dehydroiodination of 3-iodo-1,1,1,3,3-pentafluoropropane, but again, it is difficult to obtain a large amount of the raw material at low cost (do., Synthesis of Fluoroorganic Compounds).
OBJECT OF INVENTION
It is an object of this invention to provide a method of producing 1,1,1,3,3-pentafluoropropane with a good yield by using 1,1,3,3,3-pentafluoropropene as a raw material.
It is another object of this invention to provide a method of producing 1,1,1,3,3-pentafluoropropane and/or 1,1,3,3,3-pentafluoropropene with a good yield by using 2-chloro-1,1,3,3,3-pentafluoropropene as a raw material.
It is a further object of this invention to provide a production method which is industrially feasible and easy to produce 1,1,3,3,3-pentafluoropropene by using 1,1,1,3,3-pentafluoro-2,3-dichloropropane as a raw material.
CONSTITUTION OF INVENTION
The inventors have studied methods of producing 1,1,1,3,3-pentafluoropropane by hydrogenating 1,1,3,3,3-pentafluoropropene in a gas phase. As a result of the study, the inventors found that though the usual hydrogenation of 1,1,3,3,3-pentafluoropropene at room temperature in the presence of a palladium catalyst results in a low conversion yield, a high reaction temperature improves the conversion yield and the object material Can be obtained with a high yield, thus achieving the first invention. Furthermore, the inventor found that when active carbon is used as a carrier of palladium catalyst, a selectivity of 100 percent can be attained.
That is, the first invention is a method of producing 1,1,1,3,3-penta
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Aoyama Hirokazu
Nakada Tatsuo
Seki Eiji
Yamamoto Akinori
Daikin Industries Ltd.
Wu Shean C.
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