(812c) Optimization of the Production of Glycerol Carbonate From Glycerol Using a Mg/Al/Zr Catalyst

The use of a mixed oxide catalyst Mg/Al/Zr is presented in this work for the transesterification reaction of glycerol to produce carbonate glycerol. Glycerol carbonate synthesis involves glycerol, dimethyl carbonate and a suitable catalyst for the transesterification reaction, in this case using Mg/Al/Zr mixed oxides. The optimization of the reaction conditions was performed to determine a reaction process at a low operative cost, i.e. atmospheric pressure and a moderate reaction temperature. Several catalysts of Mg/Al type HDL catalyst and mixed oxides were initially synthesized and evaluated in the reaction. The catalysts were characterized by X-ray diffraction and BET surface area. The best catalyst was found to be the mixed oxide Mg/Al/Zr. This catalyst showed a higher basicity than other catalysts tested, and required considerably less time than that required for other catalysts to reach the same conversion degree of glycerol. The objective was then to analyze the effect of each factor (calcination temperature, Mg/Al/Zr molar ratio, reaction temperature, glycerol to dimethyl carbonate molar ratio and glycerol to catalyst weight ratio) on the yield of glycerol carbonate with the Mg/Al/Zr catalyst. Moreover, these factors were optimized through the use of an experimental design to obtain the maximum glycerol carbonate yield. The glycerol carbonate yield was found to be dependent on the reaction temperature, glycerol to dimethyl carbonate ratio and the catalyst amount. The optimal operating conditions to maximize the glycerol carbonate yield were a reaction temperature of 90 °C, a glycerol to dimethyl carbonate molar ratio of 1:5 mol/mol and a glycerol to catalyst weight ratio of 1:0.15.