Air Oxidation of Hydrocarbons. IV. The Effects of Varying Solvent and the Mechanism of Uninhibited Chain Termination

Synthesis, DFT Calculations, and In Vitro Antioxidant Study on Novel Carba-Analogs of Vitamin E

“…Basing on oxygen consumption plots (∆[O 2 ]) with time, for each of the tested compounds, the values of the induction period, τ [s], were graphically determined (linear regression method), as is presented in Figure 5. The values of inhibition rate constant k inh [M −1 s −1 ] and the stoichiometric factor n (e.g., the number of peroxyl radicals trapped by a molecule of an antioxidant) were calculated according to the following equations: • C were determined from preliminary set of experiments from the length of the induction period, using PMHC (1c) as a reference antioxidant, for which n = 2; thus, transformed Equation (2) can be applied [26]:…”

“…For autoxidation of styrene in chlorobenzene at 30 • C initiated by 0.05 M AIBN, the rate of initiation was determined to be R i = 5.53 × 10 −9 Ms −1 , while for autoxidation of cumene, it was found to be R i = 4.56 × 10 −9 Ms −1 under the same conditions. , for autoxidation of styrene and cumene in chlorobenzene at 30 °C were determined from preliminary set of experiments from the length of the induction period, using PMHC (1c) as a reference antioxidant, for which n = 2; thus, transformed Equation (2) can be applied [26]:…”

Quantum-Mechanical Studies on Oxidation Potentials and Antioxidizing Action of Phenolic Compounds.

“…The straight line in Fig. 1 is expressed as Fc = 2.807(Cnx)2 -0.459 (6) with a correlation coefficient, r =0.977. By using eq.…”

“…By using eq. 6 and the values of (Cnx) ,2 the critical oxidation potentials, F", can be predicted for (15) For example, the reference hydrocarbon anion for phenol is benzyl anion (CeHiCHa-).…”

“…As the possible evidence for this, they mentioned that N-deuterated N-methylaniline3 and diphenylamine6 show identical kinetics to those of the undeuterated substances and that , -dimethylaniline and N,N, N'jN'-tetramethyl-p-phenylenediamine are fairly potent inhibitors despite the absence of a labile N-H function in their structures.5 On the basis of these observations, they suggested that the inhibition reaction involves the rate-determining step R'OO• + Inhibitor < > Complex (13) in which the complex is assumed to be a loosecomplex. 6 Recently, an ionic mechanism of termination of the chains by amines was proposed by Pedersen,23 who formulated it as…”