Process for the preparation of chloro-fluoro-butenes

摘要

2-Chloro- and 2,3-dichloro-1,1,1,4,4,4-hexafluorobut-2-ene is prepared by reacting a chlorobutene derivative of the formula (I> Cl2C=CH-X (I), in which X represents CCl=CCl2 or CCl2-CCl2H, with hydrogen fluoride and chlorine in the presence of a catalyst at temperatures in the range from 50 to 550 DEG C, avoiding hexachlorobutadiene as starting material.