Single electron transfer mechanism of oxidative dechlorination of 4-chloroanisole on copper(II)-smectite

4-Chloroanisole was found to react with Cu(II)-smectite forming a blue clay-organic complex. The presence of radical cation intermediates in the complex was confirmed by electron spin resonance and infrared spectroscopy. The radical cation intermediates were formed via an initial one electron oxidation of 4-chloroanisole by Cu(II)-smectite. Coupling of the radical cation of 4-chloroanisole (I) with a neutral 4-chloroanisole molecule gave a biphenyl radical cation (VI). Single electron transfer from the dimerized radical cation (VI) to Cu(II)-smectite resulted in the formation of a nonradical dication biphenyl intermediate (V). Reaction of the blue clay-organic complex with methanol resulted in the formation of the final dechlorinated dimeric product, viz., 4,4'-dimethoxybiphenyl. Chloride ion was recovered form the methanol extract. It is suggested that Cu(II)-smectite may be a useful catalyst in the oxidative polymerization and dechlorination of chlorinated aromatic toxicants. The products of these reactions should be significantly less toxic than the parent compounds. 15 references, 4 figures, 2 tables.