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Electronic and Hydrogen Bonding Effects on the Chain-Breaking Activity of Sulfur-Containing Phenolic Antioxidants

“…In the case of bisphenol 4 , the length of the induction period is one-half of the expected value since only two peroxyl radicals per molecule are trapped, despite the presence of two phenolic moieties. The same result was previously found by other authors who performed similar measurements in cumene at different temperatures . The presence in the ESI-MS spectra of the products of reaction between 4 and AIBN of an intense peak at m / z = 285 (not shown) corresponding to a cleavage product in which sulfur is oxidized to sulfate seems to suggest that, after trapping two peroxyl radicals, the bisphenol 4 splits in two fragments not capable of further inhibiting the autoxidation reaction.…”

“…This was unexpected since d[O 2 ] / d t values twice as small and stoichiometric coefficients twice as large as those of the monophenols 1 − 3 were predictable in the bisphenols as a result of the presence of two hydroxyl groups, as found with 4,4‘-methylenebis(2,6-di- tert -butylphenol) . It should, however be emphasized that a similar result ( n = 2) was reported by Farzaliev et al when inhibiting with 4 the AIBN initiated autoxidation of cumene at 60 °C …”

“…In recent studies on the antioxidant effect of bis(4-hydroxy-3,5-di- tert -butylphenyl) sulfides and polysulfides, it has been reported that these compounds retard the hydrocarbon oxidation both by terminating the oxidation chains by hydrogen transfer to peroxyl radicals and by catalyzing the decomposition of hydroperoxides. The inhibiting activity was found to increase with the number of sulfur atoms.…”

3,5-Di-tert-butyl-4-hydroxybenzaldehyde derivatives as antioxidants in cumene oxidation

“…They readily react with peroxy radicals and terminate oxidation chains [1]. Proceeding with studies in the fi eld of synthesis and antioxidant behavior of sulfur-containing additives [2][3][4][5][6], we prepared in this work a series of 3,5-di-tert-butyl-4-hydroxybenzaldehyde (1) derivatives.…”