Epoxidation of Oleic Acid Using Acetic Acid and Citric Acid as Hybrid Organic Oxygen Carriers

This study investigates the epoxidation of oleic acid employing a hybrid oxygen-carrier system consisting of acetic acid and citric acid.Conventional peracid-based epoxidation pathways often suffer from instability and undesirable side reactions, which restrict their broader application.To overcome these challenges, the influence of three key parameters, namely reaction temperature, hydrogen peroxide, and the oxygen carrier molar ratio, was systematically investigated.The results indicate that moderate reaction conditions (55-65 °C) enhanced oxirane formation and maintained epoxide stability, while both hydrogen peroxide and oxygen carriers at a stoichiometric ratio (1 : 1) achieved the highest epoxide yield of approximately 21 %.Increasing either parameter beyond the optimum promoted oxirane ring-opening and degradation reaction, leading to reduced conversion.A first-order kinetic model was established and optimised using MATLAB, and the predicted values showed excellent agreement with experimental data (R 2 = 0.9927), confirming the reliability of the developed model.Overall, the use of acetic-citric acid hybrid oxygen carriers improved epoxide stability, minimised secondary reactions, and provided a greener alternative for producing high-quality epoxidised oleic acid with potential application in sustainable polymer and bio-based chemical industries.