Efficient and selective oxidation of olefins and alcohols using nanoparticles of WO3-supported manganese oxides (W1-xMnxO3)

Nanoparticles of manganese oxide supported on tungsten oxide (WO3) were synthesized by an impregnation method using Mn(NO3)(2) and Na2WO4 as a source of manganese and tungsten. Atomic absorption spectroscopy (AAS), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the physicochemical properties of compounds. Due to a highly dispersed state of manganese or insertion of manganese ions into the WO3 lattice, no manganese oxide peak was observed in the XRD patterns of the W1-xMnxO3 nanoparticles. Investigation of W1-xMnxO3 by AAS and EDX showed that the relative atomic abundance of Mn present in the bulk and on the surface of WO3 was 3.68% and 4.8% respectively. For the first time, the catalytic oxidation of olefins and alcohols, in the presence of these materials and hydrogen peroxide (H2O2) as a green oxidant at room temperature was studied. The recoverability and catalyst leaching of the W1-xMnx3O nanoparticles in epoxidation of styrene as a model reaction were also investigated.