Process for the preparation of 1,1,1,2-tetra-fluoroethane.

摘要

The subject of the invention is a continuous process for the manufacture of 1,1,1,2-tetrafluoroethane (134a) from 2-chloro-1,1,1-trifluoroethane (133a) and hydrofluoric acid in the gas phase in the presence of a chromium-based catalyst. According to the invention, the gas flow exiting from the reactor is distilled to separate at the head a flow containing nearly all the HCl and at least 90 % of the 134a produced by the reaction and at the foot a flow containing at least 90 % of the unconverted reactants (133a and HF) and the latter flow is directly recycled to the reactor, without any purification operation.