Oxidation of Alcohols Catalyzed by Transition Metal Substituted Phosphomolybdates

Synthesis and characterization of mono transition metal-substituted Keggin-phosphomolybdates, PMo11M (M = Mn, Co, Ni, Cu) as well as their use as efficient catalysts for aerobic oxidation of alcohols in presence of TBHP as a radical initiator was explained. Optimization of reaction condition was also elucidated for oxidation benzyl alcohol as a model reaction. Moreover, oxidation of various alcohols such as cyclopentanol, 1-hexanol and 1-octanol with PMo11M was also presented under optimized conditions. All the catalysts showed good catalytic activity with excellent selectivity for the desired products as well as a higher TON. The catalytic activity of recycled catalysts was also described and it was found that catalysts are stable under present reaction conditions. The system not only catalyzes the reaction but also avoids the use of organic solvents as it was carried out under solvent free conditions. A probable reaction mechanism was also explained for the oxidation of alcohols.