A flash photolysis study of the rate of the reaction OH + CH4→ CH3+ H2O over an extended temperature range

Zellner, R.; Steinert, W

doi:10.1002/kin.550080307

Cited by 55 publications

(18 citation statements)

References 24 publications

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“…To illustrate how Monte Carlo simulations may be applied to evaluate kinetic data consider the last example discussed by Cvetanović et al [1], an analysis of Zellner and Steinert's measurements of the rate of from 298 to 892 K [18]. The results of least-OH + CH 4 squares fits of their nineteen points to Kooij's three parameter equation, and Table I and shown in Figures 1 E/k T, B and 2.…”

Section: Examples Simple Illustrationmentioning

confidence: 98%

The use of Monte Carlo simulations to evaluate kinetic data and analytic approximations

Hessler

1997

Int. J. Chem. Kinet.

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Experimental kineticists are always faced with the problem of reducing kinetic data to extract physically meaningful information. A particularly vexing problem arises when different models reproduce the data but yield different values for the physical parameters. For over forty-five years Monte Carlo simulation techniques have been used to study the statistical behavior of parameters extracted from data. Not only do these simulations provide realistic uncertainties, correlation coefficients, and confidence envelopes, but they also provide insight into the nature of the model. These insights may be obtained by viewing two-dimensional scatter plots of the fractional changes of the parameters and one-dimensional histograms of the distributions of the changes in the parameters. Monte Carlo simulations are illustrated with examples from and the high-pressure rate coefficient for OH ϩ CH : CH ϩ H O 4 3 2 methyl-methyl association. A more complex problem involves models for pressure-dependent rate coefficients in the falloff region. We have modeled methyl-methyl association with five of the most current analytic approximations for behavior in the falloff region. All of these reproduce the data to within their uncertainties. However, when Monte Carlo techniques are applied the correlations between the parameters and the nonlinear nature of their behavior become evident. We postulate that the statistical behavior of the parameters of a model may be used to distinguish one model from another and, thereby, identify those analytic approximations that hold promise for further investigation and utilization. Finally, the recent advent of highspeed workstations implies that Monte Carlo simulations should become a routine part of the analysis of kinetic data.

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Section: Examples Simple Illustrationmentioning

confidence: 98%

The use of Monte Carlo simulations to evaluate kinetic data and analytic approximations

Hessler

1997

Int. J. Chem. Kinet.

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“…Zellner and Steinert [58] reco.mmended k3 = 10 9 • 71 cm 3 / (mol s) at 298 K as a reliable value. In figure 6, rate cons~ants in the fQrm IQg (k/T2) are plQtted against reciprocal temperature.…”

Section: ~Cpot=omentioning

confidence: 98%

“…The best straight line drawn through the best rate constant at 298 K gives k3 = 106.93T2exp( -1485/T) (30) The fit to the experimental data is go.od. [58] value Qf k3 at 298 K, eq (15), int k 3 =10-1J • 6 k 3 , and a value of AS~9;8 -27 cal/(mol K) (the same as for HO+H 2 [3]), k~=109.84T'ex:p(-1787jT) cm 3 j(mol s). (31) Equation (31) is drawn in figure 7.…”

Section: ~Cpot=omentioning

confidence: 99%

Semi-empirical extrapolation and estimation of rate constants for abstraction of H from methane by H, O, HO, and O2

Shaw¹

1978

Journal of Physical and Chemical Reference Data

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It has been concluded that for extrapolating rate constants of atom transfer reactions to and from high temperatures, a useful form of the rate constant is k=A T~exp ( -C IT), where A and C are fitted constants. For kf[cm 3 { (mol s) 1 and T{K, on the basis of previous experimental data, the values of log A and C for the following reactions are: H+CHI =H2 +CH::, log A=7.15. C=4449; O+CH!=OH+ClL, log A=6.71, C=3240; HO+CH4 =H!O+CH:, log A=6.93, C=1485 and Oz+CH~=O"H+CH .. , log A=6.93, C=26I53. At all temperatures, abstraction by HO IS faster than by O. The form of the ,rate constant is equivalent to assuming that ~Cp 0 t, the heat capacity at the constant pressure of activation, is zero. When ~CJl°:i: was estimated and assumed to be constant (in principle, a more accurate assumption than ~CpOt=O), the fit to the experimental data was slightly worse. It is confirmed that at 400 to 700 K, the kinetic and thermodynamic equilibrium constants for the reaction H +CH~=H2+CH: are significantly different. (At 1340 K, they are in agreement.) K.ey words: Estimated rate constants; hydrogen abstraction; methane combustion.

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“…However, recent developments in apparatus design have increased the temperature range of the kinetic measurements and have bridged the gap between the relatively low temperatures (up to ~600K) of earlier work to those of flame and shock tube studies. Zellner and Steinert [23] have modified the FP-RA apparatus to allow measurements at temperatures of up to ~1000K. Felder et at.…”

Section: A Direct Techniquesmentioning

confidence: 99%

Reactions of OH radicals with inorganic compounds in the gas phase

Paraskevopoulos

Singleton

1988

Reviews of Chemical Intermediates

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A flash photolysis study of the rate of the reaction OH + CH₄→ CH₃+ H₂O over an extended temperature range

Cited by 55 publications

References 24 publications

The use of Monte Carlo simulations to evaluate kinetic data and analytic approximations

The use of Monte Carlo simulations to evaluate kinetic data and analytic approximations

Semi-empirical extrapolation and estimation of rate constants for abstraction of H from methane by H, O, HO, and O2

Reactions of OH radicals with inorganic compounds in the gas phase

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