PROCESS FOR PRODUCING 1,1,1,2,2-PENTAFLUOROETHANE, PROCESS FOR PRODUCING 2,2-DICHLORO-1,1,1-TRIFLUOROETHANE, AND METHOD OF PURIFYING 1,1,1,2,2-PENTAFLUOROETHANE

摘要

A process for producing HFC-125 by dividing the reaction system into a first reaction zone for the vapor-phase reaction of mainly perchloroethylene with HF in the presence of a catalyst and a second reaction zone for the vapor-phase reaction of HCFC-123 (CF3CHCl2) and/or HCFC-124 (CF3CFHCl) with HF in the presence of a catalyst, wherein the first reaction zone is kept under a high pressure while the second reaction zone is kept under a low pressure. This process serves to keep a high conversion of perchloroethylene and increase the selectivity of HFC-125 while retaining a catalyst life. A process for purifying HFC-125 by the reaction of a mixture composed of at least 85 vol. % of HFC-125 and at most 15 vol. % of CFC-115 with hydrogen in the presence of a catalyst. This process serves to moderate the reaction conditions, reduce the absolute amount of the by-products formed, and purify HFC-125 efficiently.