MCM-41 immobilized 12-silicotungstic acid mesoporous materials: Structural and catalytic properties for esterification of levulinic acid and oleic acid

Abstract 12-silicotungstic acid (H 4 SiW 12 O 40 , HSiW) was successfully immobilized in the mesoporous molecular sieves MCM-41, which was prepared by an open synthesis method without hydrothermal process, to form a novel catalyst. The HSiW/MCM-41 catalysts preserve the hexagonal mesoporous features of MCM-41 and the typical Keggin structure of bulk HSiW. Up to a loading of 45 wt.%, the HSiW species are found to be homogeneously dispersed on the surfaces or inside the pores of MCM-41 frameworks. The influences of various catalytic reaction parameters such as the reaction temperature, reaction time and types of alcohol on the conversion of levulinic acid were investigated to characterize the catalytic performances of the mesoporous catalysts. Remarkably, the results show that the conversion value could reach 100% under the optimized conditions. The esterification reaction of oleic acid with methanol was also utilized to evaluate the catalytic performances of the mesoporous materials. The HSiW/MCM-41 catalysts exhibit excellent reusability in the esterification reactions and the yield of methyl oleate is as high as 81.2%.