PROCESS FOR PRODUCING PENTAFLUOROETHANE AND FOR PURIFYING 1,1,1,2-TETRAFLUOROETHANE

The invention relates to a process for producing pentafluoroethane from unsaturated compounds with two carbon atoms substituted by hydrogen and possibly fluorine, especially trifluoroethylene. The process can also be used in a process for purifying R134a of such unsaturated compounds. 1,1,1,2-tetrafluoroethane (R134a), a substitute for CFC be produced by addition reaction of hydrofluorides to trifluoroethylene (R1123). Due to the method, unsaturated CHF components, especially the initial compound, are present as traces in the product and have a toxic effect. It has been found that such unsaturated CHF components in R134a can be removed by reaction with high-valency metal fluorides, especially CoF3. Pentafluoroethane (R125) is formed which is not toxic and can, if desired, be removed from the R134a by ordinary processes like distillation and is a useful substance. Surprisingly, R125 and R134a are not fully fluorinated by high-valency metal fluorides in suitable conditions.