Effect of phthalocyanines supported carbon nanotube for the catalytic oxidation of benzyl alcohol

Abstract

A series of tetra-substituted metal phthalocyanine-multi-walled carbon nanotube composites ([4a (OPh-p-Cl)MPc]-MWCNTs) were fabricated, which were used to effectively catalyze the oxidation of benzyl alcohol. The as-prepared composites were characterized by ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction spectroscopy, scanning electron microscope and transmission electron microscope. In order to improve the catalytic activity, the effects of solvent, amount of oxidant, amount of catalyst, temperature and reaction time on catalytic oxidation of benzyl alcohol to benzaldehyde were studied. It can be found that the Cu phthalocyanine based composite [4a (OPh-p-Cl)CuPc]-MWCNTs have the best catalytic activity in the oxidation of benzyl alcohol. The conversion rate of benzyl alcohol can reached 70%, the selectivity of benzaldehyde was 87%, and the yield of benzaldehyde can reached to 61%. In addition, a possible mechanism for the enhanced catalytic activity of the optimized [4a (OPh-p-Cl)MPc]-MWCNTs has been discussed.