Kinetic modeling of the benzyl+HO2 reaction

Silva, Gabriel da; Bozzelli, Joseph W.

doi:10.1016/j.proci.2008.05.040

Cited by 62 publications

(64 citation statements)

References 29 publications

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“…In both cases, we found fitted activation energy from calculations of VTST to be very close to the corresponding reaction energy (i.e. [44]. Because of this treatment, larger A factors (i.e.…”

Section: High-pressure Limit Reaction Rate Constantssupporting

confidence: 59%

Reactions of HO2 with n-propylbenzene and its phenylpropyl radicals

Altarawneh

Dlugogorski

2015

Combustion and Flame

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Abstraction of an H atom from the propyl side chain by hydroperoxyl radicals (HO 2 ) constitutes a central reaction in the low-temperature oxidation of n-propylbenzene (nPB).Herein, we calculate reaction rate constants for H abstraction from primary, secondary and benzylic sites in nPB. Rate of abstraction of a benzylic H atom dominates that of a secondary H atom with negligible abstraction of the primary H atom at T ≥ 600 K. We present the reaction enthalpies for 1-phenyl-1-propyl (R1), 1-phenyl-2-propyl (R2) and 1-phenyl-3-propyl (R3) radicals, and compare the computed reaction rate constants and bond dissociation enthalpies with analogous scarce literature values. Addition of HO 2 radicals to radical sites in R1, R2 and R3 proceeds in a highly exothermic process and results in the formation of HO 2 -phenylpropyl adducts. Mapped potential energy surfaces illustrate all plausible exit channels of the three HO 2 -phenylpropyl adducts. Master equation calculations for the three phenylpropyl + HO 2 reactions indicate that direct O-OH bond fission and water elimination control the fate of the adducts leading to the formation of ketonic-type structures. Results from this study should be useful to update kinetic models for the low-temperature oxidation of alkylbenzenes in general.

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Section: High-pressure Limit Reaction Rate Constantssupporting

confidence: 59%

Reactions of HO2 with n-propylbenzene and its phenylpropyl radicals

Altarawneh

Dlugogorski

2015

Combustion and Flame

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“…[39] For several open-shell species, such as benzyl radical( PhÀCH 2 ·, 3), benzylperoxy radical (PhCH 2 OO·, 5), benzyloxy radical (PhCH 2 O·, 7), hydroxybenzyl radical (PhC·(H)(OH), 14), phenylcarbonyl radical( PhC·(O), 15), and benzoyloxy radical (PhC(O)O·, 21)f ormation enthalpies are those recommended in the compilation of Luo. [20] We note in passing that for some of theses pecies, such as 3 [41,42] and 7, [10,43] significantly different values have been derived from experimental or theoretical studies. This is even true for someo ft he apparently simple closed-shell species, such as benzyla lcohol (9), for which Papina et al derived an enthalpy of formation of À94.6 AE 3.0 kJ mol À1 using combustion calorimetry.…”

Section: Resultsmentioning

confidence: 95%

Initiation Chemistries in Hydrocarbon (Aut)Oxidation

Sandhiya

Zipse

2015

Chemistry A European J

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For the (aut)oxidation of toluene to benzyl hydroperoxide, benzyl alcohol, benzaldehyde, and benzoic acid, the thermochemical profiles for various radical-generating reactions have been compared. A key intermediate in all of these reactions is benzyl hydroperoxide, the heat of formation of which has been estimated by using results from CBS-QB3, G4, and G3B3 calculations. Homolytic O-O bond cleavage in this hydroperoxide is strongly endothermic and thus unlikely to contribute significantly to initiation processes. In terms of reaction enthalpies the most favorable initiation process involves bimolecular reaction of benzyl hydroperoxide to yield hydroxy and benzyloxy radicals along with water and benzaldehyde. The reaction enthalpy and free energy of this process is significantly more favorable than those for the unimolecular dissociation of known radical initiators, such as dibenzoylperoxide or dibenzylhyponitrite.

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“…For salicylic alcohol, an approximate determination using the group-additivity Joback-Reid method [61] was published [62], giving a value of -67.12 kcal/mol in good agreement with our recommended value. Da Silva and Bozzelli [63,64], using a simpler theoretical method (G3B3) suggested a value of 31.1 kcal/mol for the benzyloxyl radical and 29.6 kcal/mol for the benzylperoxyl radical. Both values are larger than the best ones we found and, moreover, they suggest that the latter is more stable than the former, contrary to what we found.…”

Section: Insert Tablementioning

confidence: 99%

Enthalpies of formation of the benzyloxyl, benzylperoxyl, hydroxyphenyl radicals and related species on the potential energy surface for the reaction of toluene with the hydroxyl radical

Ventura¹,

Kieninger²,

Salta

et al. 2019

Theor Chem Acc

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The reaction of toluene (T) with OH • produces addition products as well as the benzyl radical (TR). TR can react with OH • or O2 to produce oxygenated species, for many of which there is no experimental information available. We present here theoretically determined heats of formation (HFs) of 17 such species using the non-isodesmic reactions on the potential energy surface (PES) of TR+O2 and T+OH • +O2. For those species the experimental HFs of which are known, we obtained a good correlation between experimental and theoretical values at the G4 (r 2 =0.999) and M06/cc-pVQZ (r 2 =0.997) levels, thus showing the goodness of the methods used. Previously unknown HFs of other radicals (benzyloxyl, spiro [1,2-dioxetane benzyl], hydroxyphenyl, and benzylperoxyl) and closed shell species (salicylic alcohol, benzo[b]oxetane and p-hydroxy cyclohexa-2,5dienone) were later determined using those methods.

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Kinetic modeling of the benzyl+HO2 reaction

Cited by 62 publications

References 29 publications

Reactions of HO2 with n-propylbenzene and its phenylpropyl radicals

Reactions of HO2 with n-propylbenzene and its phenylpropyl radicals

Initiation Chemistries in Hydrocarbon (Aut)Oxidation

Enthalpies of formation of the benzyloxyl, benzylperoxyl, hydroxyphenyl radicals and related species on the potential energy surface for the reaction of toluene with the hydroxyl radical

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