Epoxidation of biodiesel with hydrogen peroxide over Ti-containing silicate catalysts

The heterogeneously catalyzed epoxidation of methyl oleate with hydrogen peroxide in the liquid phase is reported using different catalysts such as TS-1, Ti-MCM-41, TiOx-SiO2, and MOx and WOx supported on Al2O3 or SiO2. At 323 K, in acetonitrile as the solvent and with an industrial TS-1 catalyst, an epoxide selectivity of 87% at 93% conversion is achieved after 24 h. Variation of the catalyst mass, particles size and the reaction temperature proove that the conversion is limited by mass transport to the outer crystal surface of the catalyst. With TS-1 as the catalyst, also the unsaturated fatty acid methyl esters (FAME) in biodiesel can be epoxidized with a conversion of 90% and selectivity of 76%. A higher TON than over Ti-MCM-41 or even the industrial TS-1 catalysts is reached, when TS-1 with nanoscaled particles and stacked morphology is applied as the epoxidation catalyst. The latter was synthesized by microwave-assisted synthesis and possesses Ti sites in similar coordination geometry as conventional TS-1 as shown by DR-UV-Vis spectroscopy. (C) 2012 Elsevier Inc. All rights reserved.