Chemically modified Jatropha curcas oil for biolubricant applications
Nurazira Mohd Nor, Nadia Salih, Jumat Salimon
Abstract
Jatropha curcas oil is one of interesting renewable resources for preparation of biolubricants. However, direct application of this oil as a biolubricant is restricted due to its low oxidative stability. This drawback can be overcome by molecule structural redesign through a chemical modification process at its unsaturated functional groups. Jatropha curcas oil was modified via epoxidation, ring opening and esterification processes. Its conversion to the epoxidized oil was performed by using in situ performic acid as a catalyst, then reaction with oleic acid in the presence of p-toluenesulfonic acid as a catalyst in the ring opening process. The final esterification process with oleic acid was catalyzed by sulfuric acid. Molecular structures of the modified oil were determined by measurements of the oxirane oxygen content and by Fourier-transform infrared (FTIR), proton and carbon nuclear magnetic resonance (1H NMR and 13C NMR) spectroscopy analyses. The results showed that the oxidative stability, viscosity, flash point and pour point of the final product were significantly improved. In specific, the ring opening and esterification processes inducing branching and bending in the final oil molecular structure have resulted in the improved viscosity index of 135, the pour point of -29?C and the increased flash point of 250?C.