Patent ID: 8415515

Claim:
A process for the production of pentafluoroethane which comprises the steps of: (i) in a first reactor or a first plurality of reactors reacting perchloroethylene with hydrogen fluoride in the vapour phase at elevated temperature in the presence of a fluorination catalyst to produce a composition comprising dichlorotrifluoroethane, hydrogen chloride, unreacted perchloroethylene, less than 2 weight % of chlorotetrafluoroethane and pentafluoroethane combined and less than 5 weight % of compounds having the formula C 2 Cl 6-x F x , where x is an integer of from 0 to 6, based on the total weight of organic compounds in the composition; (ii) subjecting the composition from step (i) to a separation step to yield a purified composition comprising at least 95 weight % of dichlorotrifluoroethane and less than 0.5 weight % of compounds having the formula C 2 Cl 6-x F x , where x is an integer of from 0 to 6, based on the total weight of organic compounds in the composition; and (iii) in a second reactor or a second plurality of reactors reacting the composition from step (ii) with hydrogen fluoride (HF) in the vapour phase at an elevated temperature in the presence of a fluorination catalyst to produce a composition comprising pentafluoroethane and less than 0.5 weight % of chloropentafluoroethane, based on the total weight of organic compounds in the composition, and wherein step (i) of the process is operated so that 30 weight % or more of the perchloroethylene that is fed to the at least one reactor remains unreacted having passed through the or each reactor.