Catalytic Hydrocracking -Hydrogenation of Castor Oil Fatty Acid Methyl Esters over Nickel Substituted Polyoxometalate Catalyst

Diverse methods for converting biomass into fuels are necessary for the functioning of a flexible and profitable biorefinery. Catalytic hydrocracking of fatty acids and their derivatives, which can be used as biofuels precursors, is rather scarce. In this work we introduce a highly selective hydrocracking process for castor oil fatty acid methyl esters (FAME) over a bifunctional polyoxometalate (POM) catalyst. Keggin-type polyoxometalates catalysts, with tungsten as addenda atoms, were examined in this research. Nickel substituted Keggin polyoxometalate, K-6[SiNi(H2O)(11)O-39]center dot 13H(2)O (Ni-POM), supported over g-alumina, demonstrated the highest activity towards selective hydrocracking on a specific position in methyl ricinoleate, which is the predominant component of castor oil FAME. In addition, hydrogenation is unavoidable in this reaction and hydrogenation products, such as those with reduced double bond or without the hydroxyl group of methyl ricinoleate, are always present. The Ni-POM catalyst and other examined polyoxometalates catalysts were characterized using XRD, EDX, XPS and BET. The products were identified with GC-MS and their yields were recorded with GC.