Multiple Oxo-Vanadium Schiff Base Containing Cyclotriphosphazene as a Robust Heterogeneous Catalyst for Regioselective Oxidation of Naphthols and Phenols to Quinones

Abstract

Grafting of multiple oxo-vanadium Schiff base moieties to cyclotriphosphazene provided an efficient and recyclable heterogeneous catalyst for the regioselective oxidation of naphthols and phenols to quinones by using t-butylhydroperoxide as oxidant. One of the main advantages of the developed catalyst was the presence of multiple oxo-vanadium moieties in close proximity which made the developed catalyst more active as compared to its homogeneous oxo-vanadium Schiff base. After the reaction, the catalyst was easily recovered from the reaction mixture by simple filtration and reused for five runs without loss in activity.