Reductive dehalogenation of bromoform in aqueous solution.

The hybrid semiconducter-macrocycle catalyst TiO2-cobalt phthalocyanine promotes the solar photolysis of aqueous bromoform under anaerobic conditions. The major decomposition products are dibromoethane and HBr. Bromomethane and methane were produced only after prolonged photolysis (30 hr). Acetone, derived from added 2-propanol, was the only observed oxidation product. Preliminary experiments showed that electrolytic reduction of aqueous carbon tetrachloride at a vitamin B12-modified silver electrode produced the expected lower homologues but with surprisingly high yields of methane.