Accelerated Decomposition of Benzoyl Peroxide by Dibenzenesulfenimide: One-Electron Transfer or Nucleophilic Substitution ?

Article abstract of DOI:10.1021/jo01302a022

Dibenzenesulfenimide (PhS)2NH reacts with many organic peroxides in solution at room temperature to produce radical as well as nonradical intermediates.The stable dibenzenesulfenimidyl radical (PhS)2N* is a key intermediate and provides a convenient means for monitoring these reactions.We have studied the reaction of (PhS)2NH with benzoyl peroxide (BPO) in detail, and we find this sulfenimide to be among the most effective species in inducing the decomposition of BPO known to date.The BPO is quantitatively converted to benzoic acid; (PhS)2NH gives diphenyl disulfide,N2 and tar.The kinetics of the appearance of the sulfenimidyl radical are complex.Interestingly, although the sulfenimidyl radical is clearly formed, the dibenzenesulfenimide/benzoyl peroxide reaction is ineffective as an initiator of styrene polymerization.A mechanism for the interaction of the sulfenimide and benzoyl peroxide that involves the formation of a tetravalent sulfur compound is proposed.This reaction and other related systems from the literature are discussed in terms of competing one-electron-transfer and/or nucleophilic-substitution mechanisms.