Zirconia supported 12-molybdophosphoric acid: Physico-chemical characterization and non-solvent liquid phase oxidation of styrene

A series of solid catalysts comprising 12-molybdophosphoric acid (PM) and hydrous zirconia (Z) have been synthesized by wet impregnation and characterized by various physico-chemical techniques. The structure of PM onto the surface of the support has been confirmed by ³¹P MAS NMR and XPS. Non-solvent liquid phase oxidation of styrene has been carried out with 30% aqueous H₂O₂ as an oxidant by varying different parameters over fresh catalysts. The catalytic activity of calcinated catalysts has also been evaluated by carrying out same oxidation reaction under optimized conditions. As solid catalysts, they show high conversion of styrene with good selectivity towards benzaldehyde and styrene epoxide.