First Series Transition Metal Substituted Phosphotungstates as Catalysts for Selective Non-Solvent Liquid Phase Oxidation of Styrene to Benzaldehyde: A Comparative Study

Keggin type Cobalt and Manganese substituted phosphotungstates were synthesized and characterized by various physicochemical techniques. They were efficiently used for liquid phase non-solvent oxidation of styrene under mild reaction conditions. It was found that the catalytic systems are efficient in achieving higher conversions with high turn over numbers (TONs) and are selective towards benzaldehyde (BA). The complexes behaved as homogeneous catalysts under present oxidation conditions and were efficiently regenerated after a simple workup and reused up to two cycles.