Optimization of operational conditions for biodiesel production from cottonseed oil on CaO-MgO/Al2O3 solid base catalysts

In the present work, biodiesel production from the transesterification of the cottonseed oil with ethanol over a novel CaO-MgO/Al2O3 catalyst has been studied, and the effects of experimental factors such as loading of CaO-MgO on Al2O3, reaction temperature and molar ratio of ethanol to cottonseed oil on the oil conversion were investigated. CaO-MgO/Al2O3 catalysts were prepared via a conventional co-precipitation method. These catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and temperature-programmed desorption of CO2 (TPD-CO2). The operational conditions on the cottonseed oil conversion were investigated using Design of Experiment (DOE). The optimized conditions predicted by Box-Behnken design were found to be 14.4 wt% loading of CaO-MgO on Al2O3, with molar ratio of ethanol to cottonseed oil = 12.24 and reaction temperature = 95.63 degrees C in order to achieve a conversion of 97.62%. The predicted results agree with the experimental results (12.5 wt% loading of CaO-MgO on Al2O3, molar ratio of ethanol to cottonseed oil = 8.5 and reaction temperature of 95 C with 92.45% conversion). Crown Copyright (C) 2014 Published by Elsevier B.V. on behalf of Taiwan Institute of Chemical Engineers. All rights reserved.