A kinetic study of quicklime-catalyzed sunflower oil methanolysis

• Quicklime as a cheap catalyst for methanolysis of sunflower oil.
• The influence of reaction conditions on the methyl esters synthesis.
• The use of an empirical model describing the sigmoidal process kinetics.
• Successful simulation of triacylglycerols and methyl esters concentrations with time.

The quicklime-catalyzed sunflower oil methanolysis was studied at mild reaction conditions. Quicklime (calcined at 550 °C for 4 h) in amounts of 1.0, 2.5, 5.0 and 10.0% (based on the oil weight) and different molar ratios of methanol-to-oil (6:1, 12:1 and 18:1) were employed to investigate their influence on the methyl esters content and the kinetics of the methanolysis reaction. The optimal methanol-to-oil molar ratio and quicklime amount for achieving the highest fatty acid methyl esters content were established to be 12:1 and 5% (based on the oil weight), respectively. The sigmoidal kinetics of quicklime-catalyzed methanolysis reaction was described by a model which included the changing mechanism of the reaction and the triacylglycerols mass transfer limitation. The kinetic parameters were determined and correlated with the process variables. A good agreement between the kinetic model and the experimental data for all applied reaction conditions was observed.