Chitosan supported molybdate nanoclusters as an efficient catalyst for oxidation of alkenes and alcohols

The excellent Lewis acidity and variable oxidation states of molybdate anions for the oxidation reactions was utilized by supporting it on eco-friendly and amply available fishery waste chitosan backbone using a simple “mix and make” methodology. The comprehensive structural analysis was done by FTIR, XRD, FESEM, elemental mapping, TEM and XPS. FESEM and elemental analysis revealed the mono-dispersion of molybdate nanoclusters on the surface of the chitosan. The increase in the molybdate loading increased the size of the clusters without affecting their uniformity over the polymer. This multi-nuclear material showed high catalytic activity towards the liquid phase oxidation of alkenes and alcohols owing to the surface sorption of the molybdate nanoclusters. The oxidation of cycloalkenes gave full conversion with > 90% selectivity towards the corresponding epoxides, while the oxidation of aryl alkenes and alcohols gave good to best results in terms of catalytic activity and selectivity. The catalyst exhibited prominent reusability. Graphic abstract