In the dehydrohalogenation of 1, 2-dihalo-1, 1-diphenylethanes, 1, to 2-halo-1, 1- diphenylethene, 2, either at 76° C or at 50° C, promoted by catalytic amount of the anhydrous bromides of Fe (III), Ru (III) and Al (III) and Fe (III) chloride the chemical transformation of the metal halides was observed. In reactions carried out in vacuum or under nitrogen atmosphere, the hydrogen halide eliminated from the organic substrate ...