Process for the preparation of pentafluorethane (R 125)

摘要

Prepn. of pentafluoroethane (R 125) comprises reacting perchloroethylene with hydrogen fluoride in the gas phase in the presence of a chromium-contg. catalyst which is prepd. according to the following steps : (1) a water-soluble chromium (III) salt is mixed in water with magnesium (hydr)oxide and opt. graphite ; (2) the reaction mixt. is converted into a dough and dried so that the dried dough contains 4.5 - 26 wt.% chromium (calculated as Cr2O3) and at least 25 wt.% Mg (calculated as MgO) ; and (3) the dried dough is treated with hydrogen fluoride at 20 - 500 degrees C.