Arkema France

D'elf Atochem S.a.

Emmanuel Guiraud

Laurent Wendlinger

Jean-Pierre Schirmann

Michel Devic

Serge Hub

Dominique Garrait

Fabrice Domingues Dos Santos

Thierry Lannuzel

Béatrice Boussand

Dominique Guillet

Jean-Michel Galland

Philippe Leduc

The present invention relates to the preparation of trifluoroethylene (VFor TrFE) by hydrogenolyzis of chlorotrifluoroethylene (CTFE) in the gaseous phase over a group VIII metal catalyst deposited on a support. This method can be used to obtain VFin an economical manner in conditions which minimize the risk of explosion of this molecule. Using a catalyst containing a group VIII metal and, more specifically, containing Pd deposited on a support and a specific series of steps of separation and purification makes it possible to obtain excellent CTFE conversion rates and high selectivity in VFat atmospheric pressure and at low temperatures.

Method for synthesising trifluoroethylene from chlorotrifluoroethylene

The invention relates to a gas-phase continuous method for preparing 2,3,3,3-tetrafluoro-1-propene, said method comprising the following steps: (i) hydrogenation of hexafluoropropylene to form 1,1,1,2,3,3-hexafluoropropane; (ii) dehydrofluorination of the 1,1,1,2,3,3-hexafluoropropane obtained in the previous step to 1,2,3,3,3-pentafluoropropene-1; (iii) hydrogenation of the 1,2,3,3,3-pentafluoropropene-1 obtained in the previous step to form 1,1,1,2,3-pentafluoropropane; and (iv) dehydrofluorination of the 1,1,1,2,3-pentafluoropropane obtained in the previous step to form 2,3,3,3-tetrafluoro-1-propene.

Method for preparing 2,3,3,3-tetrafluoro-1-propene

The subject of the invention is a continuous process for the preparation of 1,1,1,2-tetrafluoroethane (134a) from 2-chloro-1,1,1-trifluoroethane (133a) and hydrofluoric acid in the gaseous phase in the presence of a chromium-based catalysts. According to the invention, the flow of gas leaving the reactor is subjected to a distillation in order to separate at the top a flow containing almost all the HC1 and at least 90% of the 134a produced by the reaction and at the bottom a flow containing at least 90% of the unconverted reactants (133a and HF), and the latter flow is recycled directly to the reactor, without any purifying operation.

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

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Saint Genis Laval, France

Emmanuel Guiraud