Preparation of Fluoro- and Bromofluoroaryl Compounds by Copyrolysis of Bromofluoroalkanes

Pyrolysis of tribromofluoromethane yields chiefly hexafluorobenzene. Copyrolysis of this material with several bromine-containing compounds was studied at 540 °C and under several atmospheres’ pressure of nitrogen gas. The addition of bromine or dibromodifluoromethane has very little effect on the pyrolysis products of tribromofluoromethane. Copyrolysis with carbon tetrabromide or bromoform yields increased amounts of bromopentafluorobenzene and dibromotetrafluorobenzene at the expense of hexafluorobenzene. The addition of relatively small amounts of 1,1,1-tribromo-2,2,2-trifluoroethane gives a significant yield of octafluorotoluene.