Kinetic study of in situ epoxidation of mustard oil

Abstract

• This work explores the epoxidation and kinetics of mustard oil. • A structural study was carried out using NMR and FTIR spectroscopy. • Determined epoxy equivalent weight (EEW) for calculation of reactive groups. • Reaction rate constant calculated using maximum and minimum oxirane oxygen content. This work explores the kinetics of epoxidation of mustard oil in the presence of liquid inorganic acid catalysts by in situ generation of peroxyacetic acid. The formation of the epoxide group was studied over the reaction time for various temperatures. It was found that about 84% conversion to oxirane was achieved with significantly less oxirane cleavage by in situ epoxidation process. Peroxyacetic acid was found to be a more efficient epoxidising agent than peroxyformic acid. A structural study of epoxidised mustard oil was carried out using NMR spectroscopy as well as FTIR technique. For sulphuric acid-catalysed epoxidation of mustard oil, the rate constants ranged from 34.7 to 65. 8 × 10 −6 L mol −1 s − 1, for the temperature range of 55 to 70 °C. The activation energy was found to be 44.7 kJ mol −1 . Other associated thermodynamic parameters of change in entropy, change in enthalpy, and change in free energy of activation were calculated to be –206.8 J mol −1 K −1 , 40.2 kJ mol −1, and 109.1 kJ mol −1 , respectively.