Identification of active phase for selective oxidation of benzyl alcohol with molecular oxygen catalyzed by copper-manganese oxide nanoparticles

Abstract

Catalytic activity of copper-manganese mixed oxide nanoparticles (Cu/Mn = 1: 2) prepared by coprecipitation method has been studied for selective oxidation of benzyl alcohol using molecular oxygen as an oxidizing agent. The copper-manganese (CuMn 2) oxide catalyst exhibited high specific activity of 15.04 mmolg -1 h -1 in oxidation of benzyl alcohol in toluene as solvent. A 100 conversion of the benzyl alcohol was achieved with >99% selectivity to benzaldehyde within a short reaction period at 102°C. It was found that the catalytic performance is dependent on calcination temperature, and best activity was obtained for the catalyst calcined at 300°C. The high catalytic performance of the catalyst can be attributed to the formation of active MnO 2 phase or absence of less active Mn 2O 3 phase in the mixed CuMn 2 oxide. The catalyst has been characterized by powder X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer Emmett-Teller (BET) surface area measurement, and Fourier transform infrared (FT-IR) spectroscopies. © 2013 Roushown Ali et al.