PROCESS FOR THE PREPARATION OF PENTAFLUOROETHANE (R 125)

摘要

Process for the preparation of pentafluoroethane (R 125) The invention relates to a process for the preparation of pentafluoroethane (R 125) from 1,1-dichloro-2,2,2- trifluoroethane (R 123) and hydrogen fluoride in the gas phase, which comprises using a chromium- and magnesium- containing catalyst which is obtainable by precipitating chromium(III) hydroxide by reacting 1 mol of a water- soluble chromium(III) salt with at least 1.5 mol of magnesium hydroxide or magnesium oxide in the presence of water, converting the reaction mixture into a paste containing chromium hydroxide and a magnesium salt, and then drying the paste and treating the residue with hydrogen fluoride at temperatures of from 20 to 500.degree.C.