Elf Atochem S.a.

Societe Atochem

D'elf Atochem S.a.

Eric LaCroix

Andre Lantz

Bernard Cheminal

Andr E Lantz

Francois Garcia

The invention relates to the manufacture of 1,1,1,2-tetrafluoroethane (F134a) by gas-phase catalytic fluorination of 1-chloro-2,2,2-trifluoroethane (F133a). A mixed catalyst is employed, composed of nickel and chromium oxides, halides and/or oxyhalides deposited on a support consisting of aluminium fluoride or of a mixture of aluminium fluoride and alumina. This mixed catalyst makes it possible to obtain an excellent selectivity for F134a with a high production efficiency.

Process for the manufacture of 1,1,1,2-Tetrafluoroethane

The invention relates to a process for the manufacture of 1,1,1,2-tetrafluoro-2-chloroethane and of pentafluoroethane. The process, which consists of the gas phase catalytic fluorination of at least one pentahaloethane of formula C.sub.2 HX.sub.2-n F.sub.3+n in which X denotes a chlorine or bromine atom and n the number 0 or 1 by means of hydrofluoric acid, is characterized in that there is used a mixed catalyst composed of oxides, halides and/or oxyhalides of nickel and chromium deposited on a support consisting of aluminium fluoride or a mixture of aluminium fluoride and alumina.

Process for the manufacture of 1,1,1,2-tetrafluoro-2-chloroethane and of

The invention relates to mass catalysts based on chromium and nickel oxides, obtained from a sol of chromium and nickel hydroxides. These catalysts, in which the Ni/Cr atomic ratio is between 0.05 and 5, may be used from the fluorination of halogenated hydrocarbons by HF in the gas phase.

Mass catalysts based on chromium and nickel oxides and their application

The invention relates to the purification of pentafluoroethane (F125) containing chloropentafluoroethane (F15). The F-125-F115 mixture to be purified is subjected to a fluorination stage to convert F115 into hexafluoroethane (F116) which is then separated from F125, for example by distillation.

Purification of pentafluoroethane

In order to remove the olefinic impurities (in particular 1-chloro-2,2-difluoroethylene and polyfluoropropenes) present in crude 1,1,1,2-tetrafluoroethane (F134a), a gaseous mixture of crude F134a, hydrofluoric acid and oxygen or air is treated in the gas phase, in the presence of a fluorination catalyst, at a temperature between 200.degree. and 350.degree. C. and at a pressure between atmospheric pressure and 2.5 MPa, the HF/F134a molar ratio being between 0.05 and 0.5 and the O.sub.2 /F134a molar ratio being between 0.001 and 0.1.

Process for the purification of 1,1,1,2-tetrafluoroethane

To recover the antimony contained in a solution of use antimony-containing catalyst, emananting from units for the fluorination or chlorofluorination of halogenated hydrocarbons comprising at least two carbon atoms, the solution is concentrated to the limit of distillation of antimony trichloride, an excess of chlorine is then added to convert SbCl.sub.3 to SbCl.sub.5, and SbCl.sub.5 is distilled under reduced pressure without exceeding 120.degree. C. The recoverd antimony pentachloride is sufficiently pure to be able to be recycled directly to the fluorination reactor.

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Lyons, France

Eric LaCroix