Yield, quality, kinetics and thermodynamics studies on extraction of Thevetia peruviana oil from its oil bearing seeds

Abstract

The present research shows possibility of extracting Thevetia peruviana oil from its oil bearing seeds by cold and soxhlet extraction methods, using petroleum ether as extracting solvent at room temperature and 40 to 60°C respectively. Characterisation of the oil showed that the percentage oil yield, acid value, saponification value and viscosity increased as temperature of soxhlet extraction increased, while the specific gravity and iodine value of the extracted oil decreased at high temperature of extraction in soxhlet extraction method. Cold extraction showed improved quality and oil yield, in comparison with oil obtained from soxhlet extraction method. The kinetics of the oil extracted from soxhlet extraction method was derived from mass transfer rate equation and was found to fit well with only pseudo-second order kinetic of volumetric mass transfer rate coefficient 0.04 h-1. The thermodynamics study of the extracted oil showed that ∆H and ∆S were positive while ∆G was negative, indicating that T. peruviana oil extraction process was endothermic, spontaneous and irreversible with exception to extraction at 40 and 45°C. Key words: Extraction, irreversible, kinetic, thermodynamic, quality.