Chain-breaking fused heterocyclic antioxidants; antioxidant activities of phenothiazines compared to related compounds

摘要

The antioxidant activities of phenothiazines and related diphenylamines were evaluated in the oxidation of tetralin at 60℃ and linoleic acid micelles in aqueous dispersion at 37℃ induced by an azo initiator. The antioxidant activities of phenothiazines were much higher than those of the structurally comparable diphenylamines in both systems. The results are interpreted in terms of electron donating capacity and stabilization of the aminyl radical by the sulfur atom. Semiempirical molecular orbital AMl and PM3 calculations were applied to study hydrogen abstractions of antioxidants in the chain process of autoxidation. The results indicate that the rates of oxidation during the induction period were correlated with the dissociation energy of the N-H bond.