Youngbin Kim  Seunghee Lee  Minseok Sim  Yehee Kim  Rajendra Joshi  Jong-Ki Jeon

Vol. 30,  No. 1, pp. 47-54, Mar.  2024
10.7464/ksct.2024.30.1.47

Nepalese Jatropha curcas Estrification NaOH/c-Al2O3 Transesterification Fatty acid methyl ester

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Jatropha oil extracted from the seeds of Nepalese Jatropha curcas, a non-edible crop, was used as a raw material and converted to biodiesel through a two-step process consisting of an esterification reaction and a transesterification reaction. Amberlyst-15 catalyst was applied to the esterification reaction between the free fatty acids contained in the Jatropha oil and methanol. The acid value of the Jatropha oil could be lowered from 11.0 to 0.26 mgKOH/g through esterification. Biodiesel was synthesized through a transesterification reaction between Jatropha oil with an acid value of 0.26 mgKOH/g and methanol over NaOH/c-Al2O3 catalysts. As the loading amount of NaOH increased from 3 to 25 wt%, the specific surface area decreased from 129 to 28 m2/g and the pore volume decreased from 0.249 to 0.129 cm3/g. The amount and intensity of base sites over the NaOH/ c-Al2O3 catalysts increased simultaneously with the NaOH loading amount. It was confirmed that the optimal NaOH loading amount for the NaOH/c-Al2O3 catalyst was 12 wt%. The optimal temperature for the transesterification reaction of Jatropha oil using the NaOH/c-Al2O3 catalyst was selected to be 65 oC. In the transesterification reaction of Jatropha oil using the NaOH/c-Al2O3 catalyst, the reaction rate was affected by external diffusion limitation when the stirring speed was below 150 RPM, however the external diffusion limitation was negligible at higher stirring speeds.