Studies on the kinetics of in situ epoxidation of vegetable oils
2008
Cai, Chuanshang | Dai, Honghai | Chen, Rongsheng | Su, Caixia | Xu, Xiaoya | Zhang, Shi | Yang, Liting
In the present work, the kinetics of the epoxidation of soybean oil (SBO) by peroxyacetic acid (PAA) generated in situ in the presence of sulfuric acid as the catalyst was studied at various temperatures (45, 65 and 75 °C). It was found that epoxidation with almost complete conversion of unsaturated carbon and negligible oxirane cleavage can be attained by the in situ technique. The rate constant for epoxidation of SBO was found to be of the order of 10⁻⁶ mol⁻¹s⁻¹ and the activation energy of epoxidation is 43.11 kJ/mol. Some thermodynamic parameters: enthalpy, entropy and free activation energy of 40.63 kJ/mol, -208.80 J/mol and 102.88 kJ/mol, respectively, were obtained for the epoxidation of SBO. The kinetic and thermodynamic parameters of epoxidation obtained from this study indicate that an increase in the process temperature would increase the rate of epoxide formation. The epoxidation of corn oil and sunflower oil were also investigated under the same conditions. The results show that the reaction rate is in the order of soybean oil > corn oil > sunflower oil.
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