New PVDF microcapsules for application in catalysis

Novel polyvinylidene fluoride (PVDF) porous microcapsule membranes were successfully prepared with non-solvent induced phase inversion method for the immobilization of catalyst ammonium molybdate tetrahydrate ((NH4)(6)Mo7O24 center dot 4H(2)O). The chemical-physical analysis of the new PVDF catalytic microcapsules was carried out by means of SEM, EDX, IR, DSC and XRD techniques. Catalytic activity of the PVDF catalytic microcapsules has been evaluated in the oxidation of benzyl alcohol to benzaldehyde in solvent free conditions. The polymeric microcapsules keep in contact the two phases: the organic phase, containing the substrate and the product, and the aqueous phase with the oxidant, H2O2. In literature, ((NH4)(6)Mo7O24 center dot 4H(2)O) was reported to be effective in the oxidation of alcohols with H2O2 in combination with a phase transfer catalyst in chlorinated solvents. The effect of reaction temperature, substrate: oxidant ratio, swelling of polymeric microcapsules on the reaction progress was investigated. PVDF catalytic microcapsules have given proof of their complete stability under oxidation conditions and their good recycle. (C) 2007 Elsevier B.V. All rights reserved.