Performance of Brӧnsted-Lewis acidic ionic liquids supported Ti-SBA-15 for the esterification of acetic acid to benzyl alcohol

Abstract

Brӧnsted-Lewis acidic ionic liquids (BLAILs)[3-methyl-1-(3-sulfonic acid) imidazolium zinc sulfate ([MIMPS]+(1/2Zn2+)SO42−)] with Brӧnsted acid ionic liquid [MIMPS]+HSO4- and ZnO were synthesized, and their acidities were determined by infrared pyridine probe. Ti doped SBA-15 mesoporous molecular sieves (Ti-SBA-15) were synthesized by co-condensation method. Ionic liquid [MIMPS]+(1/2Zn2+)SO42− and Ti-SBA-15 are compounded at different mass ratios by impregnation method. FT-IR, TG, XRD, N2 physical adsorption, elemental analysis, mass spectroscopy, TEM, and XPS were used to characterize the composition and structure of the catalysts. The catalytic activities of catalysts were investigated via esterification of acetic acid with benzyl alcohol (BnOH). When the reaction temperature is 90 ℃, reaction time is 3 h, nbenzyl alcohol/nacetic acid =1.8, and the amount of catalyst was 0.4 g, the conversion of acetic acid was as high as 93.8 %. After 5 cycles, the conversion of acetic acid decreased only 5%, suggesting that the resulting catalyst had good stability.