Synthesis of bio‐lubricant from non‐edible Mahua oil through epoxidation and ring opening using sulfamic acid catalyst

Abstract Vegetable oils are renewable and biodegradable resources that are environmentally friendly and exhibit excellent lubricating properties, making them promising alternatives to mineral oils for the production of lubricant base stocks. In this work, epoxidation of Mahua oil was carried out by using in situ ‐generated peracetic acid (CH 3 COOOH) to produce epoxidized Mahua oil. In the next step, the epoxide ring was opened using several straight‐ and branched‐chain alcohols, such as methanol, ethanol, 1‐propanol, 2‐propanol, butanol, isoamyl alcohol, 1‐hexanol, 1‐heptanol, and 1‐octanol. Sulfamic acid was used as a catalyst in both the epoxidation and ring‐opening reactions. Response surface methodology (RSM), based on central composite rotatable design, was used to optimize the epoxidation of Mahua oil. The iodine value and oxirane oxygen content (OOC) were measured to estimate the progress of epoxidation and ring‐opening reactions, respectively. A maximum conversion of 71.35% and a yield of 65.64% were obtained for the epoxidation of Mahua oil at 58.2 °C, an H 2 O 2 :oil molar ratio of 8.52:1, an acetic acid:oil molar ratio of 1.12:1, and a reaction time of 4.81 h. Various functional groups representing product formation were identified using Fourier transform IR analysis. The fatty acid methyl ester composition of Mahua oil, analyzed using gas chromatography, confirmed the formation of palmitic acid (18.57%), oleic acid (43.33%), and stearic acid (24.46%). Furthermore, the viscosity, thermos‐oxidative stability, and pour‐point properties of the epoxidation and ring‐opening products were analyzed using a rheometer, thermogravimetric analyzer, differential scanning calorimeter, and pour‐point apparatus, respectively, confirming an improvement in the lubricant properties of the product.