Halogen Interchnge Reaction of Halobenzenes in the Presence of Fused Salts

Abstract

When the reaction of C6H5l and Br2 were carried out in fused salt of alkali metal chloride system containing CuCl, halogen interchange reaction was mainly observed to give C6H5Br, but in the presence of of similar fused salt containing ZnCl2, large amounts of C6H5Cl were obtained together with C6H5Br. Analogous halogen interchange reaction of C6H5Br with C12 in the presece of such fused salts gave Ca-WI along with small amounts of C6H4H2 and C6H5Brcl2.When Ca-Ur was chlorinated by Cl2 in the presence of C6H5NO2 as radical inhibitor at 350C, halogen interchange reaction and chlorination were not prohibited in the presence of ZnCl2, in fused salts, but the both reactions were prohibited in the presence of the CuCl.Consideration from these results, reaction temperature and conposition of fused salts dominate the products distributions.It was supposed that in fused salt containing ZnCl2, the halogen interchange reaction proceeded mainly through an ionic mechanism and the halogenation reaction could be explained as a Friedel-Crafts type reaction. In the case of CuCl, the reaction seemed to proceed through a radical mechanism.