Optimization for Epoxidation of Malaysian Jatropha curcas Oil Based Trimethylolpropane Ester Biolubricant

Abstract

Epoxidized Jatropha curcas-based trimethylolpropane triester (ETMPJO) was prepared by the in-situ epoxidation reaction of trimethylolpropane ester (TMPJO) catalyzed by hydrogen peroxide (H₂O₂) in the presence of formic acid. The epoxidation process was optimized through the variable parameters such as hydrogen peroxide to tmpjo molar ratio, formic acid to TMPJO molar ratio, temperature and time of the epoxidation reaction. The results showed the epoxidation optimal condition was achieved at the molar ratio of TMPJO to H₂O₂ and formic acid of 1 : 2.0 and 1 : 2.5, temperature of 50 °C for 2 h, respectively. The resultant ETMPJO was characterized by using fourier transformation infrared (FTIR), nuclear magnetic resonance (NMR) spectroscopies and gas chromatography analysis. The FTIR spectrum of ETMPJO showed the appearance of peaks at 825 and 908 cm^–1 for the epoxy functional group. ¹H NMR spectrum showed a chemical shift at 2.88 ppm of the epoxide group protons. ¹³C NMR spectrum showed the chemical signal of carbon epoxide group at 54–57 ppm. At the optimal condition, the resultant ETMPJO obtained was at 91% yield with comparatively high relative conversion oxirane (RCO) of 87%. With high oxygen oxirane content (OOC) of 4.38, ETMPJO owns a good characteristic for an intermediate compound for possible further conversion to produce high-end products. Moreover, its physiochemical and lubrication characteristics indicated that ETMPJO is plausible to be used as biolubricants for industrial application.