Efficient allylic oxidation of cyclohexene catalyzed by immobilized Schiff base complex using peroxides as oxidants

Allylic oxidation of cyclohexene was carried out over a Schiff base copper complex and its immobilized analogue supported on organically modified silica. The immobilized complex has been characterized by using atomic absorption spectrophotometry (AAS), FT-IR, EPR and UV–vis spectroscopic studies and SEM image analysis. The catalytic oxidation of cyclohexene was carried out over this copper complex and the immobilized analog with different oxidants like dilute aqueous hydrogen peroxide and tert-butyl hydroperoxide at ambient conditions. Acetonitrile and water was used as solvent and dispersion medium, respectively, with or without additional acid in different sets of oxidation reactions. 2-Cyclohexen-1-one was obtained as the major product with small amounts of cyclohexene oxide, 2-cyclohexen-1-ol and 1,2-cyclohexane-diol. The activity of the immobilized catalyst remains nearly the same after two cycles, suggesting the true heterogeneous nature of the catalyst.