Optimization of reaction variables in situ transesterification of Jatropha curcas seed oil for biodiesel production

Abstract

Biodiesel was produced from seed oil of Jatropha curcas by in situ acid-catalyzed transesterification with methanol. Optimization of the reaction parameters was carried out using response surface methodology based on Box-Behnken design. All the four variables investigated were found to be significant. The empirical model obtained adequately expresses the relationship between the biodiesel yield and the statistically significant reaction variables (R² = 96.97%). The optimization result predicted an optimal biodiesel yield of 84.07% at a reaction temperature of 48°C; a reaction time of 240 min; with 5 cm³ methanol/g of the seed and catalyst concentration of 0.88M. The validation result was in agreement with the predicted biodiesel yield. The fatty acid methyl profile of the biodiesel shows that it predominantly contains methyl esters of octadecenoic acid, octadecadienoic acid and hexadecanoic acid which make up about 87% the biodiesel. The fuel properties of the biodiesel were in agreement with the requirements of Worldwide Fuel Charter Committee Biodiesel Guidelines.

Keywords: Jatropha curcas, Biodiesel, In situ transesterification, Optimization, Box-Behnken