Screening and Kinetic study of in situ Epoxidation Methyl Ester Jatropha Curcas Oil as Biolubricant Precursor

Abstract

The methyl ester of Jatropha curcas seed oil (JCO) with iodine value of 98.136 I2/100g, and the dominant fatty acid of methyl ester Jatropha curcas seed oil are oleic acid 46 % and linoleic acid 32 % was determined by gas chromatography. These fatty acids were undergoing epoxidation by peroxyformic acid generated in situ in the presence of concentrated sulphuric acid. The effect of molar ratios of hydrogen peroxide (1.5 mol to 3.0 mol) to the unsaturation fatty acid of methyl ester JCO, the molar ratio of formic acid (0.5 mol to 1.5 mol) to double bond of methyl ester JCO and reaction time (2 hours to 6 hours) were established by using two level factorial design. It was found that those major parameters that contribute highest impact of the formation of epoxy methyl ester are the molar ratio of hydrogen peroxide and formic acid. Fourier transforms infra red spectrum showed the presence of oxygen peak at 698.5 cm-1. In addition, the kinetic studied of epoxidation methyl ester JCO by generated in situ from peroxyformic acid in the presence of homogeneous catalysts and organic solvent diluents at 40 oC, 65 oC and 80 oC was investigated. The rate constants for in situ epoxidation of methyl ester JCO by peroxyformic acids in toluene in the range of 0.43–0.89 hr-1 and activation energies was obtained 19.103 KJ.mol−1. Finally, thermodynamic parameter such as entropy, enthalpy, and free energy of activation energy were found to be 3.89 kcal/mol, -78.0326 cal/mol and 30.264 kcal/mol respectively. It can be concluded that methyl ester JCO has potential to be used produce epoxy methyl ester JCO to be used as a starting feedstock for biolubricant.