A spectroscopic determination of the methyl radical recombination rate constant in shock waves

Glänzer, K.; Qüack, Martin; Troe, J.

doi:10.1016/0009-2614(76)80081-4

Cited by 64 publications

(37 citation statements)

References 22 publications

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“…The temperature dependent factors needed for a 0.6 nm bandpass are included (see Section 2) Figure S1. Plot of the experimental rate coefficients in Ar vs the best fit values from the master equation, including the high temperature data of Du et al 3 The data refer to: Slagle et al, 2 Glänzer et al, 5 Du et al, 3 Oehlschlaeger et al Figure S1, omitting the data of Du et al…”

Section: Fit To the Available Ground State Datamentioning

confidence: 99%

Reanalysis of Rate Data for the Reaction CH₃ + CH₃ → C₂H₆ Using Revised Cross Sections and a Linearized Second-Order Master Equation

et al. 2015

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Rate coefficients for the CH3 + CH3 reaction, over the temperature range 300–900 K, have been corrected for errors in the absorption coefficients used in the original publication ( Slagle Slagle J. Phys. Chem.19889224552462). These corrections necessitated the development of a detailed model of the B̃2A1′ (3s)–X̃2A2″ transition in CH3 and its validation against both low temperature and high temperature experimental absorption cross sections. A master equation (ME) model was developed, using a local linearization of the second-order decay, which allows the use of standard matrix diagonalization methods for the determination of the rate coefficients for CH3 + CH3. The ME model utilized inverse Laplace transformation to link the microcanonical rate constants for dissociation of C2H6 to the limiting high pressure rate coefficient for association, k ∞(T); it was used to fit the experimental rate coefficients using the Levenberg–Marquardt algorithm to minimize χ2 calculated from the differences between experimental and calculated rate coefficients. Parameters for both k ∞(T) and for energy transfer ⟨ΔE⟩down(T) were varied and optimized in the fitting procedure. A wide range of experimental data were fitted, covering the temperature range 300–2000 K. A high pressure limit of k ∞(T) = 5.76 × 10–11(T/298 K)−0.34 cm3 molecule–1 s–1 was obtained, which agrees well with the best available theoretical expression.

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Section: Fit To the Available Ground State Datamentioning

confidence: 99%

Reanalysis of Rate Data for the Reaction CH₃ + CH₃ → C₂H₆ Using Revised Cross Sections and a Linearized Second-Order Master Equation

et al. 2015

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“…Knowledge of the temperature dependence of this reaction is important, both because the reaction is used as a reference reaction for studying abstractions, like [5], and because the temperature dependence provides a sensitive test for theoretical treatments of recombination reactions. Most RiceRamsperger-Kassel-Marcus (RRKM) calculations, which place the activated complex atop a rotational barrier at a point on the reaction coordinate with potential energy near its maximum value, predict a strong increase in rate with increasing temperature (5). Theories which place the critical configuration at lower energies, such as the adiabatic open channel (5), minimum state density (6), or maximum free energy theoCan.…”

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confidence: 99%

“…Most RiceRamsperger-Kassel-Marcus (RRKM) calculations, which place the activated complex atop a rotational barrier at a point on the reaction coordinate with potential energy near its maximum value, predict a strong increase in rate with increasing temperature (5). Theories which place the critical configuration at lower energies, such as the adiabatic open channel (5), minimum state density (6), or maximum free energy theoCan. J. Chem.…”

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confidence: 99%

Individual rate constants of methyl radical reactions in the pyrolysis of dimethyl ether

Held¹,

Manthorne²,

Pacey³

et al. 1977

Can. J. Chem.

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Can. J. Chem. 55,4128 (1977). Dimethyl ether was pyrolyzed in a flow system at 10 to 80 Torr and 1005 K. The average concentration of CH3 radicals in the reactor was measured by ultraviolet absorption spectroscopy. Product yields were measured by gas chromatography. The system was simulated using a computer program, taking into account the warm-up of the entering gas and the occurrence of secondary reactions. Rate constants were varied to find values consistent with experimental observations. The limiting, high pressure rate constant for the recombination of CH3 was estimated to be 1010.15'0.5 C m01-I S-l. Estimated rate constants for the reactions CH3 + CH30CH3 -t CH4 + CH20CH3 and CH3 + C H 2 0 -t CH4 + CHO were 107.12+0.2 6 mO1-~ S -~ and 107.5'0.4 e mol-' s-', respectively. ANDREW M. HELD, KIM C. MANTHORNE, PHILIP D. PACEY et HOWARD P. REINHOLDT. Can. J. Chem. 55,4128 (1977).On a effectuk la pyrolyse de I'tther dimkthylique dans un systkme a flux entre 10 et 80 Torr a 1005 K. On a mesurk la concentration moyenne des radicaux CH3 dans le reacteur par spectroscopie d'absorption ultraviolet. On a mesurt les rendements de produits par chromatographie en phase gazeuse. On a simult le systtme en faisant appel a un programme d'ordinateur en tenant compte de la pkriode de rkchauffement du gaz qui entre et de I'existance de rtactions secondaires. On a fait varier les constantes de vitesse pour trouver des valeurs en accord avec les observations expkrimentales. On a estimk que la constante de vitesse a la limite de hautes pressions pour la recombinaison des radicaux CH3 est de 1010.15'0.5 t mol-I S-l. On a estimk que les constantes de vitesse des rtactions CH3 + CH30CH3 -t CH4 + CH20CH3 et CH3 + C H 2 0 -t CH4 + CHO sont respectivement de 107.12*0.2 C mol

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“…With the Table I mechanism [33] (+) and [34] (X), converted to dissociation rate constants using standard thermochemical properties (8,9]. The recombination data were extrapolated just as for the dissociation data (see text).…”

Section: Discussionmentioning

confidence: 99%

“…The essential result of our investigations is a doubling of the temperature range over which the rate of the primary decomposition step has been measured. The rate constant in second-order form is expressed by (1) log kl(cm3/mol~sec) = 111.29 -25.26 log T - 34 …”

Section: Introductionmentioning

confidence: 99%

Thermal decomposition of ethane

Olson

Tanzawa

Gardiner

1979

Int J of Chemical Kinetics

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The decomposition of C2H6 in Ar was studied by laser-absorption and laser-schlieren measurements of the reaction rate behind incident shock waves with 1300 < T < 2500°K and I .1 < p < 4.4 X mol/cm3. The experimental profiles were parameterized by suitable measures of reaction progress. Computer simulations using a 14-reaction mechanism were used to compare assumptions about rate constant expressions with the experimental parameters and to investigate the sensitivity of computed parameters to these assumptions.A rate constant expression k(cm3/mol.sec) = 2 X 10"' T-25.26 exp(-80 320/T) was found for the primary dissociation step C2H6 + M = CH3 + CH3 + M under the conditions studied; no difference in rate was discernable between M = Ar and M = C2Hs. Rate constant expressions found to be suitable for the remaining reactions of the mechanism, to some of which the computed parameters were sensitive, were in accord with previous proposals. Our results and results from earlier investigations of the primary decomposition reaction, in both forward and reverse directions, were extrapolated, using RRK methods, to obtain low-pressure limiting rate constants and found to be concordant.

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A spectroscopic determination of the methyl radical recombination rate constant in shock waves

Cited by 64 publications

References 22 publications

Reanalysis of Rate Data for the Reaction CH₃ + CH₃ → C₂H₆ Using Revised Cross Sections and a Linearized Second-Order Master Equation

Reanalysis of Rate Data for the Reaction CH₃ + CH₃ → C₂H₆ Using Revised Cross Sections and a Linearized Second-Order Master Equation

Individual rate constants of methyl radical reactions in the pyrolysis of dimethyl ether

Thermal decomposition of ethane

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A spectroscopic determination of the methyl radical recombination rate constant in shock waves

Cited by 64 publications

References 22 publications

Reanalysis of Rate Data for the Reaction CH3 + CH3 → C2H6 Using Revised Cross Sections and a Linearized Second-Order Master Equation

Reanalysis of Rate Data for the Reaction CH3 + CH3 → C2H6 Using Revised Cross Sections and a Linearized Second-Order Master Equation

Individual rate constants of methyl radical reactions in the pyrolysis of dimethyl ether

Thermal decomposition of ethane

Contact Info

Product

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Reanalysis of Rate Data for the Reaction CH₃ + CH₃ → C₂H₆ Using Revised Cross Sections and a Linearized Second-Order Master Equation

Reanalysis of Rate Data for the Reaction CH₃ + CH₃ → C₂H₆ Using Revised Cross Sections and a Linearized Second-Order Master Equation