Microwave-assisted catalytic transfer hydrogenation of biodiesel at constant microwave power

Abstract

Using Raney-Ni as catalyst, isopropyl alcohol as hydrogen donor and water as solvent, the intensification of catalytic transfer hydrogenation (CTH) of Jatropha oil biodiesel by the microwave at different constant power was studied in detail. The effects of important parameters, including catalyst loading, microwave power, isopropyl alcohol amount, water quantity, and stirring speed, on the CTH of Jatropha oil biodiesel have been investigated. For CTH of Jatropha oil biodiesel, the non-isothermal kinetics at constant microwave power of 50 W and at 75 were gained, and the results of verification showed the rate parameters calculated were credible. Furthermore, the isothermal kinetics at constant microwave power of 100 W and at 150 W were investigated. The results showed the microwave intensity had a significant influence on the reaction rate and the selectivity of CTH of Jatropha oil biodiesel. At the high microwave intensity, the reaction rate was accelerated and the selectivity was increased. It was found that the non-thermal effect from microwave truly played an important role in the strengthening of CTH reaction, and had a higher positive effect on the hydrogenation reaction of methyl linoleate to methyl oleate than on the hydrogenation reaction of methyl oleate to methyl stearate. Moreover, the performance of upgraded Jatropha oil biodiesel has been presented. Overall, the work has provided an approach to investigate the non-isothermal kinetics at constant microwave power, and our finding has clearly demonstrated the intensification from microwave played different influences on the two consecutive steps of CTH reaction for Jatropha oil biodiesel.