Catalytic Activity of Mn(III)TPP-Au/SiO_2 Composite Catalyst for Aerobic Oxidation of Cyclohexane

A new type of composite catalyst Mn(Ⅲ)TPP-Au/SiO2 was obtained by immobilizing manganese tetrayphenylporphrin on 5%Au/SiO2 catalyst,with mercaptopyridine as bridging agent,which has sulfhydryl and pyridyl groups.The as-prepared catalyst was characterized by Fourier transform infrared spectroscopy(FT-IR),elemental analysis(EA),and X-ray photoelectron spectroscopy(XPS).The catalytic oxidation of cyclohexane to cyclohexanone(One) and cyclohexanol(Ol) in air was performed as probe reaction without any solvent or promotor,and the influences of the Mn(Ⅲ)TPP-Au/SiO2 amount,reaction pressure,reaction temperature and reaction time on its catalytic performance were investigated.It was found that the activity of Mn(Ⅲ)TPP-Au/SiO2 catalyst was higher than that of pure 5%Au/SiO2 catalyst in the catalytic oxidation of cyclohexane.Under optimum reaction conditions,the conversion of cyclohexane and the total selectivity of cyclohexanone and cyclohexanol were 5.39% and 88.74%,respectively.Furthermore,the catalyst can be used repeatedly.