Comparative Extraction of Castor seed Oil Using Polar and Non polar Solvents

Abstract

Extraction of oil from castor seeds was carried out by Soxhlet apparatus using hexane at 1:3, 1:6, 1:9 solid to solvent ratios and different extraction time periods of 8, 10, 12 and 14h. The highest oil yields of 43.9, 42.8 and 45.8% were obtained at 1:3 (14h), 1:6 (14h) and 1:9 (12h) respectively. The optimum condition for the extraction using hexane as solvent was found to be solid to solvent ratio, 1:9 and time period of 12h... The same optimum condition was applied to extract the oil using different solvents (i.e. polar and non-polar) such as ethyl acetate, isopropanol, methanol, pentane, petroleum ether and cyclohexane. The result reveals highest oil yield of 49.1% with ethyl acetate at solid to solvent ratio, 1:9 and time period of 12h and the next highest yield 46.9% was obtained using methanol as solvent. Nevertheless, other solvents also gave appreciable yield in the range 42-45%. The physic-chemical properties of castor oil extracted using all the solvents were estimated and compared. The iodine value of oil indicates that it is a non-drying oil. High acid value of oil shows that it needs pre-treatment before being utilised for transesterification process.