An experimental and kinetic study of canola oil transesterification catalyzed by mesoporous alumina supported potassium

An experimental and kinetic study of the transesterification of canola oil with methanol for biodiesel production using a novel mesoporous alumina supported potassium (MAK) catalyst was conducted. The mesoporous alumina supported potassium (MAK) catalyst was synthesized via the aqueous phase sol-gel pathway involving the one-pot simultaneous self-assembly of aluminium isopropoxide (Al(i-PrO)₃) and potassium nitrate (KNO₃). The effect of reaction temperature (from 50 °C to 70 °C), methanol to canola oil molar ratio (M/O, 6:1–15:1) and catalyst loading (1.0 wt%–2.5 wt%, relative to the oil) on the biodiesel yield was investigated. The MAK catalyst achieved the highest of 91.9% biodiesel yield under the reaction conditions of: temperature of 70 °C, catalyst loading 2.0 wt% and M/O 12:1 in 24 h. The reaction rate increased with increasing reaction temperature, catalyst loading and M/O under the conditions tested. The kinetics of the transesterification was also determined and a literature kinetic model has been shown to well reproduce the experimental data. The activation energy was found to range from 20.9 to 23.4 kJ mol⁻¹. The MAK catalyzed transesterification was thought to follow an Eley–Rideal mechanism that the reaction started with methanol adsorption on the active sites of MAK, followed by surface reaction between the adsorbed methanol and triglyceride to yield methyl esters and glycerol. © 2016 Elsevier B.V.