Biodiesel production from jatropha seeds: Solvent extraction and in situ t ransesterification in a single step

Abstract

The objective of this study was to investigate solvent extractrion and in situ transesterificiltion in a single step to allow direct production of biodiesel From jatropha seeds. Experiments were conducted using milled jatropha seeds. and n- hexane as extracting solvent. The influence of methanol to seed ratio (2: 1- 6: I ). amount of alkali (KOH) catalyst (0.05-0.1 mol /L in methanol). stirring speed (700-900 rpm). temperature (40-60 "C) and reaction time (3-5 h) was examined to define optimum biodiesel yield and biodiesel quality after water washing and drying. When stirring speed. temperature and reaction time were fixed it 700 rpm. 60 "C and 4 h respectively. highest biodiesel yield (80% with a fatty acid methyl ester purity of 99.9%) and optimum biodiesel quality were obtained with a methanol to seed ratio of 6: 1 and 0.075 mol/L KOH in methanol. Subsequently, the influence of stirring speed, temperature and react ion lime on biodiesel yield and biodiesel quality was studied. by applying the randomized factorial experimental design with ANOVA (F-test at p '" 0.05), and using the optimum values previously found for methanol [0 seed ratio and KOH catalyst level. Most experiment.l l runs conducted at SO O( resulted co high biodiesel yields. while stirring speed and reaction rime did not give significantly effect. The highest biodiesel yield (87% with a fatty acid methyl ester purity of99.7%) was obtained with a methanol to seed ratio of 6: I , KOH catalyst of 0.075 mol/L in methanol. a stirring speed of 800 rpm. a temperature of 50 °(. and a reaction time of 5 h. The effects of stirring speed. temperature and reaction rime on biodiesel quality were not significant. Most of the biodiesel quality obtained in this study conformed to the Indonesian Biodiesel Standard.