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Manganese oxides supported on γ-AlO, amorphous SiO, MCM-41, and TiO prepared by an impregnation method were used as heterogeneous catalysts for epoxidation of alkenes with 30 % HO in the presence of NaHCO aqueous solution. The effect of support and manganese loading on their activity was studied. The 1.3-MnO/γ-AlO exhibited superior epoxidazing activity of styrene, compared with other supported MnO. Hydrogen temperature-programmed reduction, UV-vis and ESR analyses suggested that Mn (catalytic activity species) dominated in 1.3 % MnO/γ-AlO due to a strong interaction between MnO and γ-AlO. Recycling studies showed the catalyst was a heterogeneous one and retained its activity after recycling four times. [ABSTRACT FROM AUTHOR]

Abstract: A series of manganese oxides (MnO, Mn3O4, Mn2O3 and MnO2) were prepared and firstly applied as heterogeneous catalysts for the liquid phase epoxidation of alkenes with 30% H2O2 in bicarbonate solution. Under our experimental conditions, MnO exhibited superior activity for the conversion of styrene to achieve ca. 100% with 92.4% selectivity of epoxide, compared to the other three manganese oxides as well as other metal oxides. Furthermore, recycling studies showed the good recyclability of MnO as a heterogeneous catalyst, which did not lose the catalytic activity after four reuses appreciably. [Copyright &y& Elsevier]