Subcritical hydrolysis and supercritical methylation of supercritical carbon dioxide extraction of Jatropha oil

This study investigates supercritical carbon dioxide (scCO2) extraction of triglycerides from powdered Jatropha curcas crude seeds followed by subcritical hydrolysis and supercritical methylation of the oil extracted by scCO2 to obtain biodiesel. Effects of the reaction temperature, the reaction time and the solvent to feed ratio on free fatty acids in the hydrolyzed oil and fatty acid esters in the methylated oil via two experimental designs were also examined. Supercritical methylation of the hydrolyzed oil following subcritical hydrolysis of the scCO2 extract yielded a methylation reaction conversion of 98.3%. The activation energy of hydrolysis and trans-esterified reactions were 50.2 and 23.9 kJ/mole, respectively. This study demonstrates that supercritical methylation preceded by subcritical hydrolysis of the scCO2 oil is a feasible two-step process in producing biodiesel from powdered Jatropha seeds.