Room temperature selective oxidation of toluene over vanadium substituted polyoxometalate catalysts

Selective oxidation of toluene at room temperature was carried on vanadium containing molybdophosphoric acid supported on niobia catalysts using t-butyl hydrogen peroxide (TBHP) as oxidant. The catalysts were characterized by FT-IR, X-ray diffraction (XRD), 31P MAS NMR, Laser Raman spectroscopy and N2 adsorption. The characterization data reveals the incorporation of vanadium and retention of intact Keggin ion on the support. The catalyst activity is related to the presence of vanadium in Keggin ion. The effect of TBHP–toluene concentration on the conversion and selectivity during toluene oxidation was also studied. A plausible reaction mechanism for the selective formation of benzaldehyde was proposed. The present catalyst is highly active, selective towards benzaldehyde and reusable with out any appreciable loss in activity and selectivity.

Graphical abstractSelective oxidation of toluene to benzaldehyde is achieved at room temperature over heterogeneous niobia supported vanadium incorporated molybdophoshoric acid catalyst. The present catalyst is highly active, selective towards benzaldehyde and reusable with out any appreciable loss in activity and selectivity.Figure optionsDownload full-size imageDownload as PowerPoint slide