Electronic and hydrogen bonding effects on the chain-breaking activity of sulfur-containing phenolic antioxidants

A kinetic and thermodynamic investigation of phenols para-substituted with thiyl (SR), sulfinyl (SOR) and sulfonyl (S[O.sub.2]R) groups and ortho-substituted with thiyl groups is presented. The ESI-MS analysis of the products that are formed by reacting the sulfides with peroxyl radicals from the azoinitiator AIBM has revealed the formation of a complex mixture of products that might play a vital role in determining the overall antioxidant activity of the parent compounds.