Process Variables in Electro‐Organic Synthesis, III. Electrosorption and Mass‐Transfer as Dominating Factors in the Anodic Styrene Oxidation

Abstract

AbstractStyrene – like many other asymmetric olefins [2] – undergoes anodic oxidation to monomeric and dimeric products. The formation for both products starts with the generation of a very reactive radical cation which either solvolyzes to form the monomer or adds to the double bond of unoxidized styrene to form the dimer.Both reactions are so fast, that they proceed at the anode surface. Thus it is the surface concentration of the reactants (solvent and styrene, resp.) which governs the relative rates of the solvolysis and the addition reaction and determine the product composition. It is the styrene surface concentration which is most effectively influenced by the adsorption equilibria on different anode materials (C, Fe3O4 PbO2, Pt) and the mass transport conditions (governed by cstyr, and i/id). It is thus possible to optimize the styrene oxidation towards either monomer or dimer formation at will.