Catalytic epoxidation of alkenes over supported manganese oxide with hydrogen peroxide: effect of supports and manganese loading

Manganese oxides supported on γ-Al2O3, amorphous SiO2, MCM-41, and TiO2 prepared by an impregnation method were used as heterogeneous catalysts for epoxidation of alkenes with 30 % H2O2 in the presence of NaHCO3 aqueous solution. The effect of support and manganese loading on their activity was studied. The 1.3-MnOx/γ-Al2O3 exhibited superior epoxidazing activity of styrene, compared with other supported MnOx. Hydrogen temperature-programmed reduction, UV–vis and ESR analyses suggested that Mn2+ (catalytic activity species) dominated in 1.3 % MnOx/γ-Al2O3 due to a strong interaction between MnOx and γ-Al2O3. Recycling studies showed the catalyst was a heterogeneous one and retained its activity after recycling four times.