5593-75-9Relevant articles and documents
The effect of the medium polarity on the mechanism of the reaction of hydroxybenzenes with hydrazyl radical in aprotic solvents
Belaya,Belyj,Zarechnaya,Scherbakov,Mikhalchuk,Doroshkevich
, p. 690 - 697 (2017/05/29)
Mechanisms of the reaction of di- and trihydroxybenzenes with 2,2′-diphenyl-1-picrylhydrazyl (stable radical) in aprotic media of different polarity have been elucidated by experimental and quantum-chemical methods. Kinetic, stoichiometric, and activation
The chain-breaking antioxidant activity of phenolic compounds with different numbers of O-H groups as determined during the oxidation of styrene
Tikhonov, Ivan,Roginsky, Vitaly,Pliss, Evgeny
experimental part, p. 92 - 100 (2009/06/28)
The technique based on monitoring oxygen, consumption was applied to test 18 polyphenols (PP) and model phenolics as a chain-breaking antioxidant during the oxidation of styrene initiated by 2,2′-azobis(2,4- dimethylvaleronitril) at 37°C. The chain-breaking capability of PP was characterized by two parameters: the rate constant k1 for the reaction of antioxidants with the peroxy radical produced from styrene and the stoichiometric coefficient of inhibition, f, which shows how many kinetic chains are terminated by one molecule of PP. Rate constants k1 × 105 (in M-1 s-1) were found to be 10 (catechol), 27 (pyrogallol), 34 (3,6-di-tert-Bucatechol), 4.3 (protocatechic acid), 12 (gallic acid), 15 (caffeic acid), 1 increases when going from one to two and three adjacent O-H groups in a benzene ring (catechol and pyrogallol derivatives, respectively). At the same time, two O-H. groups in metaposition in a A-ring of flavonoids actually do not participate in the inhibition. For the majority of PP, f is near to 2 independent of the number of OH groups. The correlation of k1 with the structure of PP and the O-H bond dissociation enthalpy has been discussed.
Kinetic and thermodynamic parameters for the equilibrium reactions of phenols with the dpph. radical
Foti, Mario C.,Daquino, Carmelo
, p. 3252 - 3254 (2008/10/09)
The kinetics and energetics of the reversible reaction of phenols with the dpph. radical have been studied; steric shielding of the divalent N by the o-NO2 in dpph. seems to be the main cause of the entropic barriers of this reaction. The Royal Society of Chemistry 2006.