Determination of the cross propagation rate constants in the autoxidation of hydrocarbons by the electron spin resonance technique

The decomposition of tert-butyl hydroperoxide with lead dioxide in the presence of hydrocarbons has been studied using electron spin resonance (ESR) at 293-333 K. By simultaneously measuring the concentration of the tert-butylperoxy radical and the rate of oxygen generation, the rate constants for the cross propagation (hydrogen abstraction from hydrocarbons by the tert-butylperoxy radical) and self-reactions of tert-butylperoxy radicals could be determined directly. The rate constants for termination, chain transfer, and cross termination involving the tert-butylperoxy radical have been also determined by ESR. The simultaneous measurements of the radical concentration and the rate of oxygen generation provide an accurate and easy way for determining absolute rate constants involving the tert-butylperoxy radical at various temperatures.