Esterification over Nano solid superacid SO42-/ZrO2-Sm2O3-SiO2

A solid superacid catalyst SO42-/ZrO2 Sm2O3-SiO2 was prepared by a coprecipitation method and characterized by means of XRD, TEM and SEM. The kinetics of the esterification of palmitic acid and ethanol catalyzed by nano SO42-/ZrO2 Sm2O3-SiO2 catalyst was studied in a stirred batch reactor for the synthesis of ethyl palmitate. The effects of reaction temperature, feed molar ratio, catalyst loading and reusability of the catalyst were evaluated. The optimum conditions were as follows: n(palmitic acid):n(ethano1)=1:5, w(SO42-/ZrO2 Sm2O3-SiO2)=2.4%, reaction temperature 403K, and reaction time 2 h. The esterification efficiency of palmitic acid was about 82.6%. The experimental reaction rates were correlated using different rate models include the Eley Rideal and Langmuir Hinshelwood Hougen Watson models.