A Lewis acid catalytic process for preparing fluorocarboxylic acid halides

Selected Group III and Group V Lewis acids were found to catalyze the isomerization and rearrangement of halosulfonyldifluoromethyl group (RfCF2SO2X, where X is either chlorine or fluorine) to form fluorocarboxylic acid halides (RfCOX). Fluorodesulfoxylation of the halosulfonyldifluoromethyl group yielded SOF2 as one of the two sulfur-containing oxides. Product analysis would suggest that both Lewis acid catalyzed and halogen exchange reactions are occurring and are dependent upon the starting halosulfonyldifluoromethyl material and Lewis acid.