Saeid Farhadi,* Zaynab Babazadeh and Mansoureh Maleki

Department of Chemistry, University of Lorestan, Khoramabad, Iran E-mail: farhadi.s@lu.ac.ir

Abstract
Sol-gel silica-supported heteropolyoxotungstate (H₄SiW₁₂O₄₀/SiO₂), prepared by incorporating H₄SiW₁₂O₄₀ cluster into a silica matrix via sol-gel technique, was used as an efficient heterogeneous photocatalyst for oxidation of alcohols by O₂. Irradiation of a series of primary and secondary benzylic alcohols in acetonitrile solvent over H₄SiW₁₂O₄₀/SiO₂ under O₂ atmosphere resulted in the corresponding aldehydes and ketones selectively and in high yield. Non-benzylic alcohols were less reactive under the conditions estabilished here. The photocatalyst  has been reused several times, without observable loss of activity and selectivity. Eventually, heterogeneous photocatalyst considerably is more active than the unsupported H₄SiW₁₂O₄₀._.

Keywords: Photooxidation, Benzylic alcohols, Heterogeneous, Polyoxometalates, Photocatalyst, Sol-gel silica-supported