Electron spin resonance and kinetic studies on the liquid-phase autoxidation of tetralin with lead dioxide

The autoxidation of tetralin with lead dioxide has been studied at 291-323 K. The application of electron spin resonance (ESR) to this reaction has enabled the tetralin peroxy radical (a chain propagating agent) to be detected during the reaction. By measuring simultaneously the concentration of tetralin peroxy radical and the rate of oxygen absorption, the rate expressions for both the radical concentration and oxygen absorption have been determined under the same conditions. A reaction mechanism has been proposed such that the chain initiation involves the formation of the peroxy radical from the hydroperoxide over the catalyst surface and their desorption into the homogeneous phase, where the chain propagation and the chain termination proceed. The simultaneous measurements of the radical concentration and the rate of oxygen absorption have made the accurate determination of the absolute rate constants of the propagation and the termination possible.