(513ct) Solventless Catalytic Etherification of Glycerol over ?-Alumina Supported Ca/Ce Mixed Oxides

In this study, the solvent-less etherification of glycerol was studied and carried out in presence of calcium–cerium mixed oxides supported on γ-alumina as efficient catalysts. The catalysts were successfully prepared by the incipient wetness impregnation using Ce(NO₃)_3(aq) and Ca(NO₃)_2(aq) as precursor solutions, followed by calcination at 550°C – 750°C for 6 hours. Various instruments including BET, XRD, SEM, and ICP-OES analysis were employed for characterization of these catalysts. Typically, the etherification reactions of glycerol were carried out from 220°C to 260°C in nitrogen atmosphere. Furthermore, the design-of-experiment (DOE) principle, mainly response surface methodology (RSM) with central composite design (CCD), was attempted to optimize the combined yield of diglycerol and triglycerol in linear form. Three factors in the DOE, including the reaction temperature, the reaction time and the dosage of catalysts. The combined yield of diglycerol and triglycerol in linear forms was adopted as the response factor. Under the optimal reaction conditions, near 80% glycerol could be converted to oligoglycerols after 8 h using Ca-Ce/γ-alumina catalysts, prepared from the molar ratio of Ca/Ce as 3/1, with a catalyst dose as 2 wt% based on the initial mass of glycerol. A selectivity of 89% for di-glycerol and tri-glycerol in linear form could be achieved, accordingly.