Quantitative Analysis of the Epoxidation of Waste Cooking Oil Biodiesel by 1 H NMR

High Resolution Image Download MS PowerPoint Slide The valorization of waste cooking oils (WCO) through biodiesel production represents a sustainable strategy aligned with circular-economy principles. Beyond its use as a renewable fuel, biodiesel serves as a precursor of high-value derivatives such as biolubricants and polymer additives. In this study, methyl (MB) and ethyl (EB) esters derived from WCO biodiesel were epoxidized using peracetic acid. Quantitative 1 H NMR (q 1 H NMR) spectroscopy was applied, using the terminal methyl group as an internal reference and the oxirane protons for quantification. Maximum conversions of 74.25 ± 0.04% (MB) and 80.62 ± 0.11% (EB) were achieved at 1.67% and 2.00% peracetic acid, respectively. Higher concentrations led to decreased conversions due to oxirane-ring opening and secondary oxidation. Ethyl esters showed higher reactivity but also a greater degradation tendency. The developed q 1 H NMR method proved robust and industrially relevant, establishing 1 H NMR as a reliable quantitative tool for monitoring biodiesel epoxidation reactions.