Mechanism of Formation and Decomposition of C 6 H 5 (O 2 • )C(OH)C 6 H 4 OH

In the present theoretical study, the thermochemical properties of Ph(O 2 • )C(OH)PhOH and considered products of its oxidation are calculated using the DFT approaches (M062X, B3LYP, wB97XD, M08HX, MN15) at the 6−311++G(d, p) level of theory. The DFT values of Δ ra H o (Y i ) of the atomization of considered structures are corrected using the linear calibration dependencies reported for the peroxides as well as for the hydrocarbons (including aromatic and simple oxygenated compounds). The values of Δ f H o (Y i , CORR) ± 3SD i , derived from the corrected values of Δ ra H o (Y i , CORR), are coordinated by the intersection of their 3SD i intervals, determined previously. The values of Δ f H o (Y, MEAN) ± 2SD Y of the Ph(O 2 • )C(OH)PhOH (2F), Ph • ─OO─C(OH)PhOH (3G), HOPh • ─OO─C(OH)Ph (2G), PhC(OH) 2 PhOH (1H), Ph(O 2 H)C(OH)PhOH (4G) and Ph(O • )C(OH)PhOH (1G) (corresponded, respectively, to −159.4 ± 6,−55.2 ± 6,−61.5 ± 3.7,−385.8 ± 6,−293.4 ± 1.4,−148.9 ± 6 kJ/mol), as well as the values of E a ‡ = 127.8 ± 7, 121.2 ± 8, 17.2 ± 5, 19.4 ± 3 kJ/mol, determined, respectively, for the reactions (R21a), (R21b), (R22a), (R22b) and the values of the rate constants of associated reactions, are reported for the first time. According to calculations, the replacement of >C • H by OH group increases the values of dissociation energy (DE) of >C(X)─O 2 • , >C(X)O─O • , >C(X)O─H, PhC(X)OO─ • PhOH, and HOPhC(X)OO─ • Ph bonds, but decreases those values of >C(X)O 2 – H, HOPhC(X) OO• Ph, and PhC(X) OO• PhOH bonds. As a result of increased stability of the >C(X)─O 2 • bond ( X = OH), the higher temperatures can be used for the chain production of p ‐PhC(O 2 H)HPhOH and p ‐PhC(O 2 H)(OH)PhOH at high concentrations of p ‐PhCH 2 PhOH. On the contrary, the contribution of reactions (R21a) and (R21b) to the oxidation is significant under low concentrations of p ‐PhCH 2 PhOH. Its also found that the stable intermediate O 2 π–π cluster, predicted for the >C • (H) radical, is not observed for the reaction of >C • (OH) with O 2 , due to the formation of a hydrogen bond between the OH group and partially charged O 2 δ− .