ELECTROCHEMICAL CATALYSIS IN MICROEMULSIONS - DYNAMICS AND ORGANIC-SYNTHESIS

Microemulsions are clear microheterogeneous fluids made from water, oi l, and surfactant. They provide cheaper and less toxic alternatives to organic solvents. In this paper, we review progress in understanding reaction dynamics and designing mediated electrochemical syntheses in microemulsions. Rates of mediated electrochemical reactions in conduct ive microemulsions can be enhanced by preconcentration of reactants in a dynamic film on the electrode surface, or more generally by control ling the formal potential of the mediator in the fluid. The electrode/ fluid interface in microemulsions probably consists of a dynamic layer of surfactant molecules packed more loosely on the electrode than in aqueous micellar solutions. Microemulsions afforded good yields of car bon-carbon addition products in reactions mediated by the cobalt compl ex vitamin B-12. Excellent stereoselective control in microemulsions m ade with the cationic surfactant cetyltrimethylammonium bromide was de monstrated for the catalytic cyclization of 2-(4-bromobutyl)-2-cyclohe xen-1-one to 1-decalone. Electrochemical synthesis in microemulsions m ay be a viable future approach to environmentally friendly methods of producing organic chemicals. (C) 1997 Elsevier Science S.A.