A combination of microvolumetry, the rotating sector method, ESR, 1H NMR, and IR allowed to establish a detailed mechanism of liquid‐phase oxidation of vinyl compounds X1CH=CHX2 and X1CH=CH–CH=CHX2 (X1 and X2—a polar substitute: С6Н5–, CO–, СOO–) initiated by azobisisobutyronitrile. A distinctive feature of the mechanism is the fact that the oxidation chain is carried out by a low‐molecular hydroperoxide radical joining the π‐bond. For nine compounds in the temperature range of 303–353 K, relative chain propagation and termination rate constants were measured (k2•k3−0.5). Absolute values of k2 were obtained for diphenylethylene (110 L·mol−1·s−1), ethyl ether of trans‐phenyl‐pentadiene acid (13 L·mol−1·s−1), and methyl ether of trans‐phenyl‐pentadiene acid (14.2 L·mol−1·s−1) at T = 323 K. For the same conditions, 10−8k3 were calculated for diphenylethylene (0.87 L·mol−1·s−1) and methyl ether of trans‐phenyl‐pentadiene acid (1.21 L·mol−1·s−1). A cyclic mechanism of the oxidation chain termination on introduced antioxidants (stable nitroxyl radicals of the piperidine series (>NO●) and the transition metal compounds (Men)) was established. The inhibition factor (f) showing how many reaction chains are terminated by the one particle of the antioxidant is equal to 102. The cyclic chain termination is caused by the following reactions: HO2● + >NO● → NOH + O2, HO2● + NOH → >NO● + H2O2 (for >NO●) and HO2● + Men → Men+1 + HO2●−, HO2● + Men+1 → Men + H+ + O2 (for Men).

The kinetics of oxidation (323 K) of bicycloolefins from the norbornene series: norbornene, vinyl norbornene, ethylidenenorbornene, and norbornadiene, inhibited by phenols (PhOH), aromatic amines (AmH), transition metal compounds (Me n ), or stable nitroxyl radicals of the piperidine series (>NO • ), in chlorobenzene solutions have been studied. It has been found that the phenols are single action inhibitors, whereas the amines, the transition metals, and the nitroxyl radicals repeatedly terminate oxidation chains. The results are explained in terms of phenomenology of the bicycloolefin oxidation process associated with the fact that peroxide radicals attack different reaction centers (π and α CH bonds), thereby resulting in the formation of different types of chain carrier radicals: low molecular weight hydroperoxide and polyperoxide radicals.

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A combination of microcalorimetry, the rotating sector method, and ESR at 323 K in the environment of 10 solvents of different polarities was used to measure rate constants of addition of hydroperoxide radicals (HO • 2 ) to π bonds of trans-1,2-diphenylethylene and trans,trans-1,4-diphenylbutadiene-1,3 (k 2 ) and disproportionation rate constants of these radicals (k 3 ). With increasing dielectric constant of the medium, k 2 values increase from 69 to 410 M −1 · s −1 , and k 3 values almost do not change and are in the range of (1.0 ± 0.2) × 10 8 M −1 · s −1 . A linear dependence of logarithm values of rate constants from the dielectric constant of the medium in the coordinates of the Kirkwood-Onsager equation was found that allows to make a conclusion about the effect of nonspecific solvation in the studied systems. The quantum-chemical analysis (NWChem, DFT B3LYP/6-311G**) of the detailed mechanism for HO • 2 addition shows that the influence of the medium polarity reflects the superposition of the effects of nonspecific and specific solvation. The scale of the polar effect will depend on how different solvation energies of the transition and the initial reaction complexes. If a value of the solvation energy of the transition complex is larger than the solvation energy of the initial reaction complex, then the reaction rate should increase with an increase of the solvent's polarity and decrease otherwise. C