Selective oxidation of benzyl alcohol was carried out using molecular oxygen under mild conditions at high turnover frequency [TOF] over palladium supported on zirconia. Zirconia was synthesized by co-precipitation of zirconyl chloride with dilute ammonia solution. Palladium supported zirconia was synthesized by incipient wet impregnation method. The high surface area of zirconia was responsible for the better dispersion of palladium metal over the support which improved the accessibility of the relatively large molecules to the active sites, leading to an improved catalytic performance for alcohol oxidation. The catalyst was characterized by different physical and analytical techniques. The catalyst was found to be active and selective towards the formation of benzaldehyde. The TOF was found to be > 6000/hour, which was amongst the highest reported in literature. Langmuir-Hinshelwood kinetic model was found to be applicable to the solvent free oxidation of benzyl alcohol oxidation.

Mohsin Siddique, Mohammad Ilyas and Muhammad Saeed