Radical reactions initiated by chelate complexes of transition metals. IX. Catalytic decomposition of benzoylperoxide and transfer reactions of free radicals to (−)‐ephedrine

Abstract

AbstractThe kinetics and mechanism of catalyzed decomposition of benzoyl peroxide in benzene in the presence of bis‐(−)‐ephedrine copper(II) chelate (Cueph) and free ligand i.e. (−)‐ephedrine were studied. The kinetics of benzoyl peroxide (BPO) decomposition in its initial stage may be described by the equation: The activation energy of this reaction is 10 kcal/mole. During the decomposition of benzoylperoxide in the presence of bis‐(−)‐ephedrine copper(II) chelate a decay of paramagnetic Cu2⊕ particles occurs, the activation energy of this process being 9.1 kcal/mole. By transfer reactions of the radicals generated by the decomposition of benzoyl peroxide with ligand (−)‐ephedrine, free radicals are formed with the unpaired spin localized at the nitrogen atom. The identification of these radicals has been accomplished by comparing the experimental ESR spectra to calculated and simulated ones.