Kinetics and thermodynamics of cottonseed oil extraction

Petroleum derived n-hexane is commercially used in solvent extraction plants due to its higher extraction efficiency in spite of the fact that it is graded as highly toxic and hazardous. The present study is based on the use of both a much safer and non toxic solvent ethanol and n-hexane for the extraction of oil from cottonseed. The extraction data were obtained by varying temperature, solvent-solid ratio and particle size, to compare the extraction efficiency of both ethanol and n-hexane. The data show that nearly the same amount of extraction is possible at a higher solvent-solid ratio for both the solvents. This study has established that the kinetics of oil extraction follows a second order reaction mechanism. The thermodynamic analysis of the data shows that both ΔHº and ΔSº are positive, and ΔGº is negative indicating that the extraction process is endothermic, irreversible, and spontaneous.