Role of radical cations in the activity mechanism of antioxidants in a series of 2,6-dialkyl substituted phenols by the example of the oleic acid oxidation

The influence of electrochemical characteristics of antioxidants (dl-alpha- tocopherol, 2,6-dialkyl substituted phenols) on the oleic acid oxidation by oxygen of air is studied at 65 degrees C, The stability of the antioxidant radical cations, which form in the first oxidation step, is presumed to be connected with their antioxidant activity. The formation of stable paramag netic intermediates is confirmed by the example of dl-alpha-tocopherol and its acetate, using ESR spectroscopy. Different reactivity of the antioxidan ts with respect to a single-electron oxidant, spatially hindered o-quinone, is studied.