Hybrid Catalysts Compose of Mono-Substituted Keggin-Polyoxometalate and Different Aminopyridine Derivatives as Catalysts for Oxidation of Benzyl Alcohol with Hydrogen Peroxide

amino- pyridinium salts of mono-substiuted Keggin-polyoxometalate were synthesized and the catalytic performance the oxidation of benzyl alcohol to benzaldehyde under solvent-free conditions with hydrogen peroxide was examined. The influences of the composition of hybrid catalyst and mole ratio of H 2 O 2 to benzyl alcohol were discussed, under the testing conditions of 70 oC, catalyst load 0.3 g, benzyl alcohol 2 mL, 30% H 2 O 2 6mL, 5 h, 2-N-(2-pyrindinemethyl) -aminopyridinium salt of FeII substituted phosphotungstate (5b) 4 HPW 11 FeO 39 exhibited the best activity, the conversion of benzyl of 95.4% with high selectivity of 98% was achieved, aminopyridine component in hybrid catalyst act as a counterion of polyoxometalate anion as well as a ancillary ligand, the interactions between organic counterion and polyoxometalate anion involve the electrostatic bond NH 3 + …Fe-POM as well as dative bond pyridine-N→Fe-POM, both affect the redox reactivity of mono-substituted polyoxometalte.