Esterification of tert-Butanol and Acetic Acid by Silicotungestic Acid Catalyst Supported on Bentonite

A series of solid acid catalysts were synthesized by incipient wetness impregnation method by varying the wt % of silicotungstic acid on bentonite. Silicotungestic acid supported on bentonite was used to catalytic synthesis of tert-butyl acetate with acetic acid and tert-butyl alcohol. The main reaction parameters such as silicotungstic acid loading on bentonite, the amount of catalyst, molar ratio of reactants, reaction temperature and reaction time have been investigated. The optimum conditions were determined as follows: silicotungstic acid loading on bentonite 25 wt %, catalyst 0.7 g, mole ratio of tert-butanol to acetic acid 1:1.1, reaction temperature 110 degrees C and reaction time 2 h. The esterification yield of tert-butyl acetate was about 87.2 %. The catalyst could be used repeatedly for many times without distinct loss in activity.