Epoxidation of methyl esters from waste vegetable oil by heterogeneous catalysts WO3/Al2O3

Abstract

The paper describes the catalytic epoxidation of methyl esters of higher fatty acids prepared from waste vegetable oils as a renewable raw material (the second important product is glycerol). Bio-epoxides as ""green products"" can be used instead of epoxides from crude oil in many applications such as bio-lubricants, biopolymers, polycarbonates, etc. The epoxidation was catalysed by gamma-alumina impregnated with tungsten (5-15 wt. %) under different reaction conditions such as the type and amount of solvent (acetonitrile, ethyl acetate and tert-butanol) and amount of catalysts (0 to 75 wt.% to ester), molar ratio to ester (from 1 to 6) and reaction time (0-24 h). Characterization of tested catalysts was carried out by various analytical methods such as XRF, XRD, Raman spectroscopy, TPD-NH3, 3 , N2 2 physisorption, Hg-porozimetry, SEM-EDX. Moreover, the ternary plot for each solvent was determined to find the homogeneous region since ester and hydrogen peroxide are immiscible liquids. Finally, according to statistical evaluationed, it was found that methyl ester conversion increases with increasing number of W--O - - O bonds.