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Updated: Aug 6, 2026

Ultrasonic-Assisted Preparation of Biodiesel Products from Vegetable Oils
Published on: April 19, 2024
Quantitative Analysis of the Epoxidation of Waste Cooking Oil Biodiesel by 1H NMR
João F A Costa1,2, Leiliane do S S de Souza2, Kidney O G Neves3
1Graduate Program in Engineering of Natural Resources of the Amazon (PRODERNA), Institute of Technology, Federal University of Pará (UFPA), Belém, Pará 66075-110, Brazil.
Abstract:
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 1H NMR (q 1H 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 1H NMR method proved robust and industrially relevant, establishing 1H NMR as a reliable quantitative tool for monitoring biodiesel epoxidation reactions.
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