Ruthenium-catalyzed oxidative dehalogenation of organics

Water-soluble ruthenium(II) complexes are effective catalysts for the deep oxidation of chlorinated organics in the presence of hydrogen peroxide or m ono-persulfate at room temperature. Reactions are conducted either in nitro methane-water two phase or in water-acetonitrile mixtures or in water alone , in the presence of a surfactant agent (if the case) with the ruthenium(II ) catalysts [Ru(H2O)(2)(dmso)(4)](BF4)(4), [RuCl2(dmso)(4)] or [RuPcS] (dms o = dimethylsulfoxide; PcS = tetra-sulfo-phthalocyaninate). The oxidation o f various chlorinated organics (chloro, bromo-, iodo- and nitro-benzene, po lychlorobenzenes, polychlorophenols) was followed by monitoring the nature and the relative amounts of the final products: chlorinated substrates are often converted into hydrochloric acid and carbon dioxide. Factors such as solvent and oxidant affect the reactions, the most favorable conditions bei ng achieved in aqueous media. Substituted benzenes are oxidized via an init ial electrophilic attack followed by a series: of faster steps, whereas wit h polychlorophenols, which are more sensitive to oxidation than substituted benzenes, the reaction is also radical in character. (C) 1999 Elsevier Sci ence S.A. All rights reserved.