Oxidation of cyclohexene catalyzed by Cu(Salen) intercalated α-zirconium phosphate using dry tert-butylhydroperoxide

Cu(Salen) intercalated a-zirconium phosphate, abbreviated as {alpha-ZrP center dot Cu(Salen)} was synthesized in situ by the flexible ligand method. The resulting compound was characterized by BET surface area. X-ray diffraction, energy dispersive X-ray analysis, Fourier transform infrared, electron paramagnetic resonance and atomic absorption spectroscopy. The catalytic activity of alpha-ZrP center dot Cu(Salen) was tested for the oxidation of cyclohexene using dry tert-butylhydroperoxide as an oxidant. In the oxidation reaction, cyclohexene was oxidized to cyclohexene oxide, cyclohexenol and cyclohexenone. Influence of various reaction parameters, viz, reaction temperature, catalyst concentration, substrate concentration and oxidant concentration were studied. Under the optimized conditions, oxidation of cyclohexene gave a maximum of 26.71% conversion. The major product followed the order of selectivity: cyclohexanone > cyclohexanol > cyclohexene oxide. Moreover, hot filtration experiments proved that the catalyst was heterogeneous. The catalyst was reused for six cycles. (C) 2011 Elsevier B.V. All rights reserved.