Rice Bran Wax as a Renewable Resource for Biolubricant Formulation

Rice bran wax (RBW) is the major byproduct of rice bran oil production, which can be directly used in several applications such as cosmetics, personal care products, and pharmaceuticals. The wax esters in RBW, containing long-chain fatty acids and fatty alcohols, could be used in biolubricant preparation. In this study, a saponification reaction was initially performed by treating RBW with 30% potassium hydroxide in isopropanol to obtain fatty acid potassium salt. Subsequently, this salt was treated with 30% HCl to obtain fatty acids via a substitution reaction, while fatty alcohols from the initial reaction were discarded. Following this, the obtained crude fatty acids were treated with 5% methanol in the presence of sulfuric acid as a catalyst to produce crude fatty acid methyl esters (FAME). Fourier-transform infrared spectroscopy (FTIR) confirms the presence of fatty acids in the RBW and the crude fatty acids obtained after the saponification and substitution reactions. FTIR was also used to characterize the crude FAMEs. In the future, a transesterification process could be then performed using the crude FAME and trimethylolpropane (TMP) to obtain TMP-esters, which can be utilized as a biolubricant precursor.