Rate constants for hydrogen atom + oxygen + M from 298 to 639 K for M = helium nitrogen and water

Hsu, K. J.; Anderson, S. M.; Durant, J. L.; Kaufman, F.

doi:10.1021/j100340a003

Cited by 46 publications

(38 citation statements)

References 2 publications

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“…With the exception of the value for h 5 ,~2 , all those rate constants were taken from the literature without adjustment. The value of h 5 , N Z which was used to generate the predictions was [8,11,14,15,201 is not important because the low concentration of this species (mole fraction <0.008) makes the calculations insensitive to this value. Figure 5 shows and, as shown in Figure 5, there are regions where the predictions are substantially independent of k35.…”

Section: Time (S)supporting

confidence: 86%

Kinetics and modeling of the H₂O₂NO_x system

Bromly¹,

Barnes²,

Nelson

et al. 1995

Int J of Chemical Kinetics

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The addition of NO (0 to 400ppm) to mixtures of Hz (ca. 1%) and 0 2 (0.7 to 22%) has been studied over the temperature range 700 to 825 K, in a flow reactor at atmospheric pressure. The overall effect of NO is to promote the oxidation of Hz but high concentrations of 0 2 actually inhibit the NO-promoted oxidation of Hz.A detailed kinetic mechanism has been constructed and found to describe the experimental observations. The promotion of the oxidation of HZ arises through the catalytic cycleThe ability of R.34 to reactivate chains normally terminated by the formation of HO2 is a key feature of this system. The predictions are highly sensitive to the rate of the reaction R.5 and the rate constants for this reaction is the only adjustable parameter required in the model. The value of h 5 ,~2 found to describe all the results K 5 ,~2 = 2.60 X lOI5 exp(+1350 cal.mol-l/RT) cm6.mol -'.s-l has an absolute uncertainty 135%. The uncertainty relative to other important rate constants in the Ha-02 system is less than 10%. 0 1995 John Wiley & Sons, Inc.

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Section: Time (S)supporting

confidence: 86%

Kinetics and modeling of the H₂O₂NO_x system

Bromly¹,

Barnes²,

Nelson

et al. 1995

Int J of Chemical Kinetics

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“…The results from these calculations are included in Figure 1. Ascanbeseen,theCAS+1+2modelpredictedaBorn-Oppenheimer barrier to reaction of about 0.1 kcal mol -1 relative to the energy 82 Bates et al, 7 Baulch et al, 9 Carleton et al, 83 Cobos et al, 6 Davidson et al, 84 Hanning-Lee et al, 85 Hsu et al, 86 Michael et al, 18 and Mueller et al 87 of the reactants, which obviously is not correct. The situation improved when the Davidson correction was included, but still, the calculation predicted a small barrier to reaction below the energy of the reactants.…”

Section: Master Equationmentioning

confidence: 99%

“…The plotted low-pressure and highpressure limiting rate coefficients are the values preferred by the IUPAC panel. 9 References: Baulch et al, 9 Carleton et al, 83 Cobos et al, 6 Hahn et al, 8 Hsu et al, 86 Kurylo, 88 Michael et al, 18 and Wong and Davis. 89 as bath gases, respectively.…”

Section: Master Equationmentioning

confidence: 99%

The Temperature and Pressure Dependence of the Reactions H + O₂ (+M) → HO₂ (+M) and H + OH (+M) → H₂O (+M)

2008

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The reactions H + O2 (+M) --> HO2 (+M) and H + OH (+M) --> H2O (+M) have been studied using high-level quantum chemistry methods. On the basis of potential energy hypersurfaces obtained at the CASPT2/aug-cc-pVTZ level of theory, high-pressure limiting rate coefficients have been calculated using variable reaction coordinate transition state theory. Over the temperature range 300-3000 K, the following expressions were obtained in units of cm(3) molecule(-1) s(-1): k(infinity)(H + O2) = (25T(-0.367) + (7.5 x 10(-2)) T(0.702)) x 10(-11) and k(infinity)(H + OH) = (4.17 x 10(-11)) T(0.234)exp (57.5/T). Available experimental data on the pressure dependence of the reactions were analyzed using a two-dimensional master equation. The following low-pressure limiting rate coefficients were obtained over the temperature range 300-3000 K in units of cm(6) molecule(-2) s(-1): k0(H + O2 + Ar) = (9.1x10(-29)) T(-1.404)exp (-134/T), k0(H + O2 + N2) = (2.0x10(-27)) T(-1.73)exp (-270/T), k0(H + OH + Ar) = (8.6x10(-28)) T(-1.527)exp (-185/T), and k0(H + OH + N2) = (1.25x10(-26)) T(-1.81)exp (-251/T). For the H + O2 reaction system, F(cent)(Ar) = 0.67 and F(cent)(N2) = 0.72 were obtained as center broadening factors, whereas F(cent)(Ar) = 0.72 and F(cent)(N2) = 0.73 were obtained for the H + OH reaction system. The calculations provide a good description of most of the experimental data, except the room temperature measurements on the H + OH (+M) --> H2O (+M) reaction.

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“…Near the second explosion limit, R2 is favoured over R1 by higher pressures, which reduces the overall oxidation reactivity and leading to the well-known negative pressure dependence [3,5]. However, whilst the rate of R1 is well characterized [6,7], the rate of R2 is more uncertain [4,[6][7][8][9][10][11][12][13][14].…”

Section: Total: 6183 (Words) Calculationmentioning

confidence: 99%

Hydrogen oxidation near the second explosion limit in a flow reactor

Jiang

Yang

et al. 2021

Proceedings of the Combustion Institute

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This work investigates the oxidation of hydrogen near its second explosion limit in a turbulent flow reactor at pressures of 1 to 8 bar, temperatures of 950 K and an equivalence ratio of 0.035. The concentrations of H2, O2 and H2O are measured along the reactor and simulated using several kinetic models from the literature. These experiments demonstrate evident negative pressure dependence from roughly 1 to 4 bar, with further increases in pressure resuming its positive impact on reaction rates.The simulated and measured species concentrations along the reactor generally agree within a factor of 2.Further investigation is then conducted to measure the rate coefficient of reaction H + O2 (+ M) = HO2 (+M) (R2), which is one of the most sensitive reactions in hydrogen's oxidation chemistry at these conditions. This investigation is conducted by using nitric oxide (NO) as a dopant and measuring the resulting, quasi-steady-state concentrations of NO2. The rate coefficients are obtained at 950 -1010 K. Combined with literature results, an Arrhenius expression is proposed, 2 2,0 N k = 4.50×10 20 (T/K) -1.73 [cm 6 mole -2 s -1 ], for the reaction rate at the low-pressure limit over 500 K -2000 K with N2 as the bath gas. Simulations using the models from the literature with the proposed Arrhenius expression for this reaction then demonstrate improved agreement with the experiments.

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Rate constants for hydrogen atom + oxygen + M from 298 to 639 K for M = helium nitrogen and water

Cited by 46 publications

References 2 publications

Kinetics and modeling of the H₂O₂NO_x system

Kinetics and modeling of the H₂O₂NO_x system

The Temperature and Pressure Dependence of the Reactions H + O₂ (+M) → HO₂ (+M) and H + OH (+M) → H₂O (+M)

Hydrogen oxidation near the second explosion limit in a flow reactor

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Rate constants for hydrogen atom + oxygen + M from 298 to 639 K for M = helium nitrogen and water

Cited by 46 publications

References 2 publications

Kinetics and modeling of the H2O2NOx system

Kinetics and modeling of the H2O2NOx system

The Temperature and Pressure Dependence of the Reactions H + O2 (+M) → HO2 (+M) and H + OH (+M) → H2O (+M)

Hydrogen oxidation near the second explosion limit in a flow reactor

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Kinetics and modeling of the H₂O₂NO_x system

Kinetics and modeling of the H₂O₂NO_x system

The Temperature and Pressure Dependence of the Reactions H + O₂ (+M) → HO₂ (+M) and H + OH (+M) → H₂O (+M)