Synthesis of immobilized Bronsted acidic ionic liquid on silica gel as heterogeneous catalyst for esterification

The Bronsted acidic ionic liquid 1-(propyl-3-sulfonate) vinylimidazolium hydrogen sulfate ([(CH2)(3)SO(3)HVIm] HSO4) was immobilized on the silica gel using tetraethoxysilane (TEOS) as silica source. The properties of samples were characterized by FT-IR, elemental analysis and TG. The results showed that [(CH2)(3)SO(3)HVIm] HSO4 had been successfully immobilized onto the silica gel, and the immobilized ionic liquid catalyst (IL/silica gel) had good thermal stability. Moreover, the IL/silica gel exhibited high catalytic activity for a series of esterification and could be separated from the reaction mixture easily. It also remained satisfactory catalytic activity for the synthesis of n-Butyl acetate after 7 times recycling. (c) 2010 Elsevier B.V. All rights reserved.