Sulfated-Alumina-Catalyzed Triacetin Synthesis: An Optimization Study of Glycerol Esterification

The catalytic activity of sulfated γ-Al2O3 was evaluated for glycerol esterification using response surface methodology (RSM) with a central composite design (CCD), having as response variable triacetin (TAG) yield. Temperature, glycerol/acetic acid molar ratio, and catalyst load were chosen as variables. The analysis of variance (ANOVA) verified that, for the studied range, only the temperature, molar ratio, their interactions, and quadratic terms were significant statistically. Among the adopted conditions for sulfated γ-Al2O3, the best result attained was 100% glycerol conversion and 39.9% TAG yield at 106.8 °C, 1:8 molar ratio, and 0.75 wt % catalysts. The optimization indicated a maximum yield of 43.6% at 106.8 °C, 1:11.4 molar ratio, and 0.53 wt % SO4 2–/γ-Al2O3. The kinetic study of the reaction rate suggests the first-order dependence on glycerol concentration and activation energy of 59.91 kJ mol–1.