Bond dissociation enthalpy of alpha-tocopherol and other phenolic antioxidants

EPR spectroscopic studies help determine equilibrium constants for reactions between galvinoxyl and various phenolic antioxidants. The known bond dissociation enthalpy (DH) of 2,4, 6-tri-tert-butylphenol helps calculate DH for the ArO-H bond of various phenols. Conformation of para alkylthio group in Probucol explains the high DH value of probucol. The alpha-tocopherol DH value is close to that of the phenolic precursor of galvinoxyl and is higher than that of 2, 6-di-tert-butyl-4-methoxyphenol.