| abstract |
To remove the unsaturated 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, of hydrofluoric acid and of chlorine is treated in gaseous phase in the presence of a fluorination catalyst at a temperature of between 100 DEG and 300 DEG C. and at a pressure between atmospheric pressure and 2.5 MPa, the molar ratio HF/F134a being between 0.05 and 0.5 and the molar ratio Cl2/F134a between 0.0001 and 0.1. |