Kinetics of the transesterification of Jatropha curcas triglyceride with an alcohol in the presence of an alkaline catalyst

摘要

Jatropha curcas alkyl ester can be produced via a transesterification reaction of J. curcas triglyceride (JCT) using an alkaline catalyst with an alcohol. In this study, the reaction was carried out in a batch reactor under various operating conditions. The kinetics study of the transesterification of JCT with methanol was conducted at various temperatures ranging from 50 ℃ to 65℃. The conversion of triglyceride (TG) and diglyceride (DG) into biodiesel followed a first-order mechanism, while the conversion of monoglyceride into biodiesel occurred too fast, thus assuming a non-limiting step. The reaction rate constants were determined and then plotted against temperatures for the determination of activation energies. The values of k_(TG) ranged from 0.11 to 0.17 min~(-1) and the values of k_(DG) ranged from 0.07 to 0.20 min~(-1). The activation energies for the transesterification of TG/DG with methanol were 27.38 and 46.72 kJ mol~(-1), respectively. The high E_a values indicate that the transesterification of J. curcas is sensitive to temperature changes.