Selective epoxidation of methyl soyate over alumina-supported group VI metal oxide catalysts (original) (raw)

Epoxidation of methyl soyate (biodiesel), soybean oil and oleic acid with tert.-butyl hydroperoxide (TBHP) was investigated over ␥-alumina-supported group VI metal oxides (CrO x /Al 2 O 3 , MoO x /Al 2 O 3 and WO x /Al 2 O 3) prepared by impregnation method. The studies revealed that 15 wt% MoO x on ␥-Al 2 O 3 was the most active catalyst (conversion >90 mol% under optimized conditions). While MoO x /Al 2 O 3 is selective mainly for epoxidation, the other catalysts are active for epoxidation as well as for decomposition of TBHP. The active species on the catalyst surface were investigated using in situ UV-visible spectroscopy. A linear correlation was observed between epoxidation activity and surface acidity of the catalyst. A new 1 H NMR method was developed to monitor the progress of epoxidation reaction which was found to be superior to gas chromatographic method in estimating the conversion of double bonds of fatty compounds.