Organic compounds -- part of the class 532-570 series – Organic compounds – Heavy metal containing
Reexamination Certificate
2000-03-27
2001-06-26
Richter, Johann (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heavy metal containing
C423S023000, C570S124000
Reexamination Certificate
active
06252099
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to processes for the manufacture of fluorinated hydrocarbons, particularly the production of fluorinated olefins such as vinyl fluoride and for the manufacture of hexafluoroethane using fluoride compositions containing silver.
BACKGROUND
Vinyl fluoride (i.e., CH
2
═CHF or VF) is a useful monomer for the preparation of fluorocarbon polymers which have excellent weathering and chemical resistance properties.
Vinyl fluoride can be produced from acetylene and hydrogen fluoride using mercury catalysts. It can also be produced by the dehydrofluorination of 1,1-difluoroethane (i.e., CHF
2
CH
3
or HFC-152a). U.S. Pat. No. 2,892,000 discloses a process for the manufacture of vinyl fluoride and 1,1-difluoroethane. In this process HF and acetylene are passed over a chromium catalyst (e.g., a chromium oxide or chromium salt catalyst) to obtain mixtures of VF and HFC-152a. A process is also disclosed in this patent for the conversion of product HFC-152a to VF using these catalysts.
Japanese Patent Application No. 52-122310 discloses a process for the manufacture of vinyl fluoride by the reaction of ethylene, HF and oxygen in the presence of a catalyst comprising metallic palladium, copper chloride and, optionally, a chloride of zinc, aluminum, cerium, iron, or nickel. The catalyst was pretreated with HF.
Hexafluoroethane is useful electronic gas. There is an ongoing interest in developing processes for the production of fluorinated olefins such as vinyl fluoride and for the production of hexafluoroethane, especially processes which do not involve the use of chlorine compounds.
SUMMARY OF THE INVENTION
A process is provided for increasing the fluorine content of an olefinic compound of the formula C
n
H
m
F
2n-m
, where n is an integer from 2 to 6 and m is an integer from 1 to 2n. The process comprises (a) contacting the olefinic compound with a metal fluoride composition of the formula (AgF)(MF
2
)
x
where M is selected from the group consisting of Mn, Fe, Co, Ni, Cu, Zn and mixtures thereof and wherein x is a number from 0 to 1, at a temperature above 200° C. sufficient to transfer F from the metal fluoride composition to the olefinic compound, thereby producing a chemically reduced metal fluoride composition comprising metallic silver; (b) oxidizing the reduced metal fluoride composition from (a) in the presence of HF to regenerate the metal fluoride composition of the formula (AgF)(MF
2
)
x
; and (c) recycling regenerated metal fluoride composition of (b) to (a).
This invention also provides a novel composition of the formula Ag
10
F
8
C
2
; and a process for producing hexafluoroethane which comprises heating Ag
10
F
8
C
2
to a temperature sufficient for its decomposition.
REFERENCES:
patent: 2631170 (1943-03-01), Fowler
patent: 2892000 (1959-06-01), Skiles
patent: 3398203 (1968-08-01), Olson
patent: 4394527 (1983-07-01), Fischer et al.
patent: 4978649 (1990-12-01), Surovikin et al.
patent: 5756834 (1998-05-01), Pasenok et al.
patent: 52-122310 (1977-10-01), None
patent: WO 97/30932 (1997-08-01), None
R.G. Plevey et al., Fluorination with Complex Metal Fluorides Part. II,Journal of Fluorine Chemistry, 3, 259-266, 1973/74.
Chemical Abstracts, vol. 103, No. 21, 25 Nov. 1985, Abstract No. 177956, “Hexafluoroethane” (re: JP 60 109533 A(Showa Denko K.K., Japan) Jun. 15, 1985).
Guo et al. Agnew. Chem., Int. Ed. (1998),37 (5), 630-632, May 1998.*
G. Guo et al., Ein vollständig umschlossenes A cetylendiid in Ag2C2·8AgF**,Agnew. Chem., 110/5, 652-654, Mar. 2, 1998.
G. Guo et al., A Fully Encapsulated Acetylenediide in Ag2C2·8AgF**,Angew. Chem. Int. Ed., 37(5), 630-632, Mar. 16, 1998.
E. I. Du Pont de Nemours and Company
Parsa J.
Richter Johann
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