Patent ID: 7138553

Claim:
A process for producing pentafluoroethane, comprising the following three steps: (1) a step of reducing the amount of a hydroxyl group-containing aromatic compound contained in tetrachloroethylene by using a purification method comprising contacting tetrachloroethylene containing, as a stabilizer, a hydroxyl group-containing aromatic compound with a zeolite having an average pore size of 4.2 to 11 Å and a carbonaceous adsorbent having an average pore size of 3.4 to 11 Å, in a liquid phase, to reduce the amount of said stabilizer; (2) a step of reacting HF with said tetrachloroethylene reduced in the amount of the hydroxyl group-containing aromatic compound through the step (1), in the presence of an alumina-chromia catalyst in a gas phase to obtain a mixed gas containing 1,1-dichloro-2,2,2-trifluoroethane and 1-chloro-1,2,2,2-tetrafluoroethane; and (3) a step of reacting HF with the mixed gas containing 1,1-dichloro-2,2,2-trifluoroethane and 1-chloro-1,2,2,2-tetrafluoroethane obtained in the step (2), in the presence of an alumina-chromia catalyst in a gas phase to obtain pentafluoroethane.