Organic compounds -- part of the class 532-570 series – Organic compounds – Halogen containing
Patent
1994-11-30
1997-10-21
Ivy, C. Warren
Organic compounds -- part of the class 532-570 series
Organic compounds
Halogen containing
570157, 570158, 570175, C07C 2118, C07C 1908
Patent
active
056798750
DESCRIPTION:
BRIEF SUMMARY
SPECIFICATION
This application is the U.S. national stage filing of PCT/JP93/00661 filed May 19, 1993 published as WO/93/25510 on Dec. 23, 1993.
FIELDS OF INDUSTRIAL APPLICATION
The present inventions relate to methods for manufacturing 1,1,1,2,3-pentafluoropropene, which is useful as an intermediate for compounds that can be substitutes for CFC and HCFC as refrigerants, blowing agents and cleaning agents, and as a monomer of macromolecule compounds, and methods for manufacturing 1,1,1,2,3-pentafluoropropane, which is a useful compound that can be said substitutes for CFC and HCFC for said uses.
CONVENTIONAL METHODS
Among the conventionally known manufacturing methods of 1,1,1,2,3-pentafluoropropene are: 1) the method of 1,1,1,2,3,3-hexafluoropropane (which is produced by hydrogenating hexafluoropropene) being reacted with an aqueous solution of KOH with a 70% to 80% concentration at 150.degree. C. (Ann. Chim. (Italy) vol. 55, 850p, 1965); and 2) the method of 1,1,1,2,3,3-hexafluoropropane being reacted with KOH in dibutylether (Izvest. Akad. Nauk S.S.S.R., Otdel. Khim. Nauk 1412p, 1960). Another known method is: the method of removing HF from 1,1,1,2,3,3-hexafluoropropane by means of granular KCl in the gaseous phase at 700.degree. C. to produce the desired product (Ann. Chim. (Italy) vol. 55, 850p, 1965).
Those methods, however, contained in the above-mentioned literature are not cost-effective because a large amount of alkali is used. As to the gaseous reaction process with KCl it does not suit to the industrial production because it produces a 30% large amount of 1,1,1,3,3-pentafluoropropene having a boiling point approximate to that of 1,1,1,2,3-pentafluoropropene and being difficult to be separate by the ordinary rectification methods cannot well separate away.
The known manufacturing method of 1,1,1,2,3-pentafluoropropane is the method of hydrogenating 1,1,1,2,3-pentafluoropropene as a raw material (Izvest. Akad. Nauk S.S.S.R. 1960, 1412-18).
This method, however, has a low yield because it also further hydrogenates the material and produces 1,1,1,2-tetrafluoropropane. The method does not suit to the industrial production because 1,1,1,2-tetrafluoropropane, which is azeotropic or pseudo-azeotropic with 1,1,1,2,3-pentafluoropropane, is difficult to separate.
OBJECTIVES OF THE INVENTIONS
An objective of the present inventions is to provide a highly cost-effective industrial method to produce 1,1,1,2,3-pentafluoropropene at high yields.
The other objective of those inventions is to provide a method with high reactivities and selectivities to produce 1,1,1,2,3-pentafluoropropane.
CONTENTS OF THE INVENTIONS
The inventors have thoroughly studied cost-effective industrial production methods of 1,1,1,2,3-pentafluoropropene, particularly those by means of the reaction to remove hydrogen fluroride from 1,1,1,2,3,3-hexafluoropropane which is obtained by hydrogenating hexafluoropropene, which is easily available. As a result, they have discovered that the contact of 1,1,1,2,3,3-hexafluoropropane in the gaseous state with active carbon causes a reaction of removing HF to produce 1,1,1,2,3-pentafluoropropene at high yields. The first invention has been achieved based on this discovery.
That is, the first invention relates to a method for manufacturing 1,1,1,2,3-pentafluoropropene characterized by the creation of reaction to remove HF from 1,1,1,2,3,3-hexafluoropropane by means of the contact of 1,1,1,2,3,3-hexafluoropropane in the gaseous state with active carbon.
For the first invention, it is essential to make 1,1,1,2,3,3-hexafluoropropane in the gaseous state contact with active carbon. This is in practice a form of vapor phase reaction in which, for example, 1,1,1,2,3,3-hexafluoropropane in the gaseous state is made flow through a reaction tube filled with active carbon at a specific temperature. The methods of the vapor-phase reaction can be the fixed-bed reaction, the fluid-bed reaction and so on.
There are no particular restrictions in terms of kinds of active carbon to be used. A granular act
REFERENCES:
patent: 2461523 (1949-02-01), Coffman et al.
patent: 2599631 (1952-06-01), Harmon
patent: 2695320 (1954-11-01), Hedrick
patent: 5059729 (1991-10-01), Gervasutti
Aoyama Hirokazu
Seki Eiji
Daikin Industries Ltd.
Ivy C. Warren
Smith Lyman H.
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