Modeling the liquid phase autoxidation of cyclohexylbenzene to hydroperoxide

Abstract

The liquid phase autoxidation of cyclohexylbenzene (CHB) to CHB hydroperoxide (CHBHP) is the key step of green production of phenol. The CHB oxidation kinetics was originally investigated by semibatch experiments under various oxygen partial pressures. Kinetic models to deal with oxygen-rich and oxygen-poor conditions were developed on the basis of free radical chain mechanism. It was found that the activation energy of the rupture of the bond OO of molecule CHBHP was close to that of cumene hydroperoxide, while the activation energy of hydrogen abstraction from the tert-butyl carbon of CHB was reasonably larger than that of cumene due to the steric effect. The kinetic model involving the oxygen addition to R (Model II) can be used to deal with various oxygen partial pressure conditions. Based on the developed kinetic model, the simulation of well-mixed reactor operated under continuous conditions was performed, and the results were in good agreement with continuous experiments.