Optimization and kinetics of tung nut oil transesterification with methanol using novel solid acidic ionic liquid polymer as catalyst for methyl ester synthesis

Optimization and kinetic modeling of methyl ester production from non-edible tung nut oil (Vernicia fordii) and methanol using a solid acidic ionic liquid polymer as a catalyst were performed in this study. A solid acidic ionic liquid polymer was synthesized using vinyl imidazole, 1, 3-propane sulfonate, N, N- dimethyl dodecylamine, allyl bromide and toluene, characterized and used for transesterification of tung nut oil for methyl esters synthesis. The optimum reaction conditions resulted in highest methyl ester yield of 91% were a tung-nut- oil -to-methanol molar ratio of 1:1.5, solid acidic ionic liquid polymer catalyst loading of 160 wt % based on the oil, reaction time of 6 h, agitation speed of 400 rpm and reaction temperature of 65 °C. Further kinetic studies performed at different temperatures revealed that the conversion of tung nut oil to methyl ester follows the first order reaction. Methyl esters were purified using an ion exchange resin and then analyzed by GC-MS. The activation energy (Ea) was calculated as 72.81 kJ mol−1. The properties of methyl esters such as kinematic viscosity at 40 °C, density at 25 °C, cloud point and pour point were also determined. Methyl esters met the quality standard defined under ASTM.