Reactions of biological antioxidants: II. Fe(III)‐catalyzed reactions of methyl linoleate hydroperoxides with derivatives of coenzymes Q and vitamin E

Lipid free‐radical oxidations of ubiquinol‐6, ubichromenol‐6, ubichromenol‐10, and α‐tocopherol hydroquinone were kinetically examined in the presence of Fe(III)‐catalyzed dissociations of preformed methyl linoleate hydroperoxides. The rates of oxidation of the chromenols increased more than those of the hydroquinones as reaction acidity was increased. Differences in thermal effects upon rates were influenced by the levels of water in the reactions. The hydroquinones exhibited faster rates relative to α‐tocopherol than the ubichromenols, while the rates for the latter varied markedly depending on the nature of the solvent.