Transesterification of sunflower oil to biodiesel fuel utilizing a novel K2CO3/Talc catalyst: Process optimizations and kinetics investigations

A novel efficient and cost-effective heterogeneous catalyst for the production of biodiesel from transesterification of sunflower oil was prepared through the impregnation of K2CO3 upon the Talc material. The physicochemical features of the catalyst were studied through several characterization analyses. The effect of the K2CO3 loading was investigated by comparing the catalytic activity of various prepared catalysts. Moreover, the effect of the calcination temperature upon the catalytic activity was examined. To maximize the yield of the produced biodiesel fuel, reaction variables such as the reaction time and temperature, catalyst concentration, and methanol: oil molar ratio were optimized. Additionally, the kinetics of the reaction was understudied. Results revealed that the catalyst with 40 wt.% of K2CO3 calcined at 823 K possessed the highest catalytic activity. That is the biodiesel production yield of 98.4 %. Moreover, the kinetic parameters of the reaction rate constant of 0.01558 min(-1), E-act of 62.4 kJ/mol, and Eyring-Polanyi's Delta H and Delta S of 59.7 kJ/mol and -103.7 J/(mol K), respectively were obtained for this material. These were revealed under the optimum reaction condition of the catalyst reactor loading of 4 wt.% as well as the methanol: oil molar ratio of 6:1 operated at 338 K. Furthermore, the optimized catalyst was demonstrated to successfully withstand the aforementioned optimum criteria up to five consecutive reaction cycles while experiencing a negligible loss of about 8% of its activity.