Interaction of thermal and kinetic parameters for a liquid-liquid reaction system: Application to vegetable oils epoxidation by peroxycarboxylic acid

A mathematical model was developed to analyze an exothermic liquid-liquid reaction system using epoxidation of oleic acid by peroxyformic acid formed in situ as an example. Kinetic and thermal parameters were included, mass transfer parameters were eliminated from the model and evaporation/condensation was taken into account. A calorimetric semi-batch reactor under isoperibolic mode was used in the experimental work. Different initial aqueous-phase concentrations of H2O2 [6.5-8.8 mol/l], water [44-45 mol/l], molar flow rate of formic acid [0.02-0.54 mol/min], initial reaction temperature [50-70 °C] and amount of organic phase [34-46 wt.%] were studied. A non-linear regression method was used to estimate kinetic (e.g., rate constant at average temperature and activation energy) and thermal parameters (e.g., reaction enthalpy) of the epoxidation and ring-opening reactions. The standard reaction enthalpy changes were estimated to be −116 kJ/mol for epoxidation reaction and −50 kJ/mol for the ring opening.