Kinetics of Corn Oil Methanolysis Reaction over Na-Modified Mesoporous Gamma Alumina Catalyst

Abstract

Understanding chemical kinetics is fundamental in substantiating the mechanisms of chemical processes, since each catalyst has its unique properties it is essential for kinetic study with introduction of a new catalyst. Mesoporous gamma alumina was doped with various amounts of NaOH, and applied in the methanolysis of corn oil to investigate its kinetic parameters. The catalysts characterization were perfomed through FTIR, N2-sorption, Basic Back Titration, and FESEM analyses. The number of basic sites increased with with amount of NaOH doping. The FESEM image demonstrates the incorporation of Na into the alumina. From the kinetics study, high k value of 0.01561 min-1 was obtained, which was connected to the presence of high level of unsaturated FFA in corn oil. The Ea and A values were 67.7 kJ mol-1 and 8.6 x 108 min-1, respectively. The Ea value indicated that the methanolysis of corn oil was chemically controlled. While higher value of A implied higher probability of successful collisions, justifying the high biodiesel yield. The positive enthalpy implies the methanolysis reaction is endothermic. While negative entropy value proposed an associative mechanism, implying a reversible reaction. Whereas positive Gibb’s free energy suggests non-spontaneous reaction, hence external energy is required for reaction to progress.