Thermodynamic properties of the species resulting from the phenyl radical with O₂ reaction system

Abstract

Phenyl radicals are formed in combustion and oxidation systems by abstraction of the phenyl—hydrogen from benzene or aromatics by active radical species and by oxidation and thermal reactions of the benzylic carbon on alkyl‐substituted aromatics. The reaction of phenyl with O2 leads to chain‐branching reactions and a number of unsaturated oxygenated hydrocarbon intermediates that may need to be included in detailed combustion models. Thermochemical parameters and structures on important species resulting from the phenyl radical + O2 association and reaction are reported in this study. Enthalpies, Δf H 0298, of a series of stable molecules, radicals, and transition state structures are calculated using ab initio (G3MP2B3 and G3) and density functional (DFT, B3LYP/6–311g(d,p) calculations, group additivity (GA), and literature data. The ab initio and density functional calculations are combined with isodesmic reaction analysis, whenever possible, to improve the accuracy of the enthalpy values. Entropies, S 0italicf298, and heat capacities, Cpf298 (T), are calculated using density functional calculations, group additivity, and literature data. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 583–604, 2008

Prediction of Thermodynamic and Kinetic Parameters for Interfacial Reactions of the SIO2System by Quantum Chemistry Methods

“…The calculation of f H 0 TS(298) from this difference reaction is similar to an isodesmic reaction and includes cancellation of errors for similar bonds in the reactant and TS structure. We point out that in a previous study (94) nineteen transition states structures have been estimated, showing that the B3LYP calculation method results in remarkably good agreement with G3MP2B3 and G3 for most of the transition state structures.…”

How to add a five-membered ring to polycyclic aromatic hydrocarbons (PAHs) – molecular mass growth of the 2-naphthyl radical (C10H7) to benzindenes (C13H10) as a case study

“…Our combined experimental and computational studies revealed critical mass growth processes involving the addition of a five-membered ring to an aromatic aryl radical (2-naphthyl) leading to two distinct three-membered ring PAHs carrying two six-and one five-membered ring: 2-ring total stabilization 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 0.00% 96.67% 0.00% 3.33% 0.00% 0.00% 0.00% 0.00% 100.00% 0.00% 0.00% 0.00% 0.00% 0.01% 0.00% 0.00% 0.00% 94.04% 0.05% 5.89% 0.00% 0.00% 0.00% 0.02% 99.98% 0.00% 0.00% 0.00% 0.00% 0.23% 0.02% 0.00% 0.09% 90.93% 0.37% 8.36% 0.31% 0.68% 0.00% 0.35% 100.00% 0.00% 0.00% 0.00% 0.00% 2.17% 0.23% 0.00% 0.97% 84…”

“…82 This oxy radical pathway could dominate above 900 K as analogous to the reaction of phenyl plus molecular oxygen. 83,84 Similarly, phenanthrenyl radicals can also lead to C13H10 isomers (Scheme 7). Moreover, Norinaga et al 85,86 proposed the mechanism for benz[f]indene formation from pyrolysis of unsaturated light hydrocarbons, however, recent experiments in our laboratory could not support this conclusion.…”

Computational modelling of de novo synthesis of Dibenzofuran: oxidative pathways of Pyrene and Benzodibenzofuran

“…The potential energy surface of vinyl [16], phenyl [17] and Dibenzofuranyl radical [13,14] oxidation pathways was carefully investigated at the ab initio level, addressing the overall similarities of these systems with respect to reactions with O 2 [14]. Thermochemical parameters of the species involved in the mechanisms were also calculated [18][19][20]. The oxidation of molecular PAHs and one-layer graphite by H, HO, NO, NO 2 , and NO 3 species was investigated to model soot particle formation [21].…”