Aerobic oxidation of sulfides catalysed by cobalt(II) complexes under homogeneous and heterogeneous conditions

The Co(II)-catalysed oxidation of alkyl- and aryl-sulfides was achieved under homogeneous and heterogeneous conditions using oxygen or air as the oxidant in the presence of excess aldehyde. The reactions in the homogeneous phase were carried out using the soluble Co(acac)(2) or Co(AAEMA)(2) complexes (AAEMA(-) = deprotonated form of 2-(acetoacetoxy)ethyl methacrylate) whereas the heterogeneous catalytic tests were carried out using the copolymers obtained by reaction of Co(AAEMA)(2) with acrylamides. Under suitable conditions excellent conversions and very good selectivities were achieved both in homogeneous and in heterogeneous phase. The supported complexes were recyclable with negligible loss of efficiency and did not suffer from metal leaching.