23531-69-3Relevant articles and documents
Modeling the Co-Antioxidant Behavior of Monofunctional Phenols. Applications to Some Relevant Compounds
Amorati, Riccardo,Ferroni, Fiammetta,Pedulli, Gian Franco,Valgimigli, Luca
, p. 9654 - 9658 (2007/10/03)
A study on the regeneration of α-tocopherol (vitamin E) by phenolic co-antioxidants in homogeneous hydrocarbon solution is reported. The behavior of some relevant phenols such as BHA, BHT, and trans-resveratrol appears to be nicely predicted by a model based on the knowledge of kinetic and thermochemical data concerning the various reactants. Despite its good reputation as an antioxidant, trans-resveratrol was found only moderately effective (kinh = 2.0 × 105 M-1 s -1 in chlorobenzene at 303 K) and unable to recycle vitamin E.
Absolute kinetics of hydrogen abstraction from α-tocopherol by several reactive species including an alkyl radical
Evans, Christopher,Scaiano,Ingold
, p. 4589 - 4593 (2007/10/02)
Laser flash photolysis and competitive techniques have been employed to study the reactions of α-tocopherol with various radicals and ketone triplets in solution. For example benzophenone triplets abstract hydrogen with rate constants of 5.1 × 109 and 3.7 × 109 M-11 s-1 in benzene and benzene/1.3 M methanol. Similar near-diffusion-controlled values were obtained for several other ketone triplets, as well as tert-butoxyl and 4-methoxybenzoyloxyl radicals. Deuterium kinetic isotope effects are frequently very small, reflecting the expected lack of selectivity of fast reactions. The reactivity of the 5-hexenyl radical toward α-tocopherol was examined by studying the competition of this process with the radical cyclization to the cyclopentylmethyl radical. The value of (1.7 ± 0.2) × 106 M-1 s-1 (at 70 °C in benzene) for this hydrogen atom abstraction from α-tocopherol makes this process exceptionally fast in comparison with the limited available rate data for reactions of carbon-centered radicals with other phenols.