Patent ID: 6037508
Filing Date: 2000-03-14
Classification: B01J,C07C

Abstract:
A process for the preparation of 1,1,1,2-tetrafluoroethane comprising the steps:(a) reacting, in the gas phase in a reaction zone, trichloroethylene with 1,1,1-trifluorochloroethane and HF, operating with trichloroethylene/1,1,1-trifluorochloroethane molar ratios ranging from 5/95 to 50/50, with HF/(trichloroethylene+1,1,1-trifluorochloroethane) molar ratios of at least 3/1, at a temperature of from 300.degree. C. to 400.degree. C., at a pressure of up to 15 atmospheres, and in the presence of a catalyst comprising Cr.sub.2 O.sub.3 carried on AlF.sub.3 in the gamma and/or beta form, to produce reaction products including 1,1,1,2-tetrafluoroethane; and(b) continuously recycling to the reaction zone the unreacted trichloroethylene and the 1,1,1-trifluorochloroethane from the reaction products leaving the reaction zone and continuously restoring the reagent molar ratios defined in step (a) by the addition to the reaction zone of fresh trichloroethylene and HF.