Studies of Organic Peroxides. X. The Reaction of Benzoyl Peroxide with Secondary Amines

Abstract The reaction of benzoyl peroxide with secondary amines, namely diphenylamine, diethylamine, piperidine and pyrrolidine was studied in benzene. The rates of reactions were followed by the thermal analysis and the titration method. The rates of reactions of these amines increase in the order diethylamine<diphenylamine<piperidine<pyrrolidine. The effect of the p, p′-substituents of benzoyl peroxide on the reaction rate was examined. The Hammett relationship with respect to p, p′-substituents held for all amines with positive ρ values. It was concluded that the reactions involve nucleophilic attack by the amines on the peroxide. Stoichiometry of the reaction was also examined by the method of thermal analysis. Diethylamine reacts with the peroxide in the 2 : 1 amine-peroxide ratio, while piperidine about 1.3 : 1 and diphenylamine 0.6 : 1, respectively. ESR spectra showed that diphenylamine and diethylamine produce fairly stable free radicals in low yields, while piperidine and pyrrolidine do not yield, detectable free radicals.