Synthesis of 1,2-dichlorotetrafluoro- and 1,2,4-trichlorotrifluorobenzenes

Abstract

1,2-Dichlorotetrafluorobenzene was obtained by reactions of chlorine with 5,6,7,8-tetrafluoro-1,4-benzodioxane and with a mixture of 3,4,5,6-tetrafluorophthaloyl chloride and 3,3-dichloro-4,5,6,7-tetrafluorophthalide at 500–550°C. Pyrolysis of pure 3,4- and 2,5-dichlorotrifluorobenzenethiols, as well as of a mixture of 3,4-, 2,4-, and 2,5-dichlorotrifluorobenzenethiols, in the presence of chlorine at 400–415°C in a flow system gave difficultly accessible 1,2,4-trichlorotrifluorobenzene.