As an extension of the analogous synthesis of aryl difluoromethyl ethers, difluorocarbene. generated from the basic hydrolysis of chlorodifluoromethane in aqueous dioxane, is brought into reaction with thiophenols, yielding aryl difluoromethyl thioethers. Further conversions lead to the m- and p-difluoromethoxy-, difluoro- niethylthio- and difluoromethylsulphonyl-substituted benzoic acids. The chemical stability of the difluoro substituents is discussed and com- pared with ...