Aroyl peroxides. Part IV. The decomposition of benzoyl peroxide in nitrobenzene. The effect of added nitrobenzene on the decomposition of benzoyl peroxide in benzene

Abstract

The kinetics and products of the reactions of benzoyl peroxide with nitrobenzene and with benzene containing 1% of nitrobenzene have been studied over a range of initial peroxide concentrations [P]₀. The rate equation in each case was dependent on the value of [P]₀, and had the two forms. (i)–d[P]/dt=k₁[P]+k_I[P]+k_3/2[P]^3/2([P]₀ <0·06–0·08M), (ii)–d[P]/dt=k₁[P]+k_II[P]([P]₀ >0·06–0·08M). The catalytic effect of nitrobenzene on the rate of disappearance of the peroxide in benzene, which is accompanied by a marked change in the distribution of the products, is discussed in terms of the formation of complexes of the radical intermediates with nitrobenzene, leading to increased concentrations of the complexed radicals, and consequent modification of their reactions.