Recombination of Methyl Radicals. 1. New Data between 1175 and 1750 K in the Falloff Region

and, Hong Du‡; Hessler, Jan P.; Ogren, Paul J.

doi:10.1021/jp951217w

Cited by 58 publications

(48 citation statements)

References 52 publications

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“…These results can be compared to the values reported in several other recent studies. Both Du et al [6] and Hwang, Wagner, and Wolff [ 5 ] are at variance with the present work, the former by greater than their published error limits, and the later within their error limits. Hwang, Rabinowitz, and Gardiner [7] are also in agreement.…”

Section: Resultssupporting

confidence: 80%

A shock tube study of methyl‐methyl reactions between 1200 and 2400 K

Davidson

Rosa

Chang

et al. 1995

Int J of Chemical Kinetics

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The methyl-methyl reaction was studied in a shock tube using uv narrowline laser absorption to measure time-varying concentration profiles of CH3. Methyl radicals were rapidly formed initially by pyrolysis of various precursors, azomethane, ethane, or methyl iodide, dilute in argon. The contributions of the various product channels, C~H I ; , C2H5 + H, CzH4 + Hz, and CH2 + CH4, were examined by varying reactant mixtures and temperature.The measured rate coefficients for recombination to CzHfi between 1200 and 1800 K are accurately fit using the unimolecular rate coefficients reported by Wagner and Wardlaw (1988). The rate coefficient for the CzH5 + H channel was found to be 2.4 (+0.5) X 10'" exp (-6480/Tj [cm3/mol-sl between 1570 and 1780 K, and is in agreement with the value reported by Frank and Braun-Unkhoff (1988). No evidence of a contribution by the C2H4 + Ha channel was found in ethane/methane/argon mixtures, although methyl profiles in these mixtures should be particularly sensitive to this channel. An upper limit of approximately 10l1 [cm3/mol-sl over the range 1700 to 2200 K was inferred for the rate coefficient of the CzH4 + Hz channel. Between 1800 and 2200 K, methyl radicals are also rapidly removed by CHs + H * 'CHz + Ha.In this temperature range, the reverse reaction was found to have a rate coefficient of 1.3 ( 2 0.3) X 1014 [cm3/mol-s], which is 1.8 times the room-temperature value. 0 1995 John Wiley & Sons, Inc.

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Section: Resultssupporting

confidence: 80%

A shock tube study of methyl‐methyl reactions between 1200 and 2400 K

Davidson

Rosa

Chang

et al. 1995

Int J of Chemical Kinetics

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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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“…In addition, reactions describing azomethane decomposition [19] and TBHP chemistry [11,16,17] were added to the mechanism. Table I presents these and other reactions that are important in the CH 3 + OH experiments.…”

Section: Ch 3 + Oh Kineticsmentioning

confidence: 99%

High‐temperature shock tube study of the reactions CH₃ + OH → products and CH₃OH + Ar → products

Vasudevan

Cook

Hanson

et al. 2008

Int J of Chemical Kinetics

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The reaction between methyl and hydroxyl radicals has been studied in reflected shock wave experiments using narrow-linewidth OH laser absorption. OH radicals were generated by the rapid thermal decomposition of tert-butyl hydroperoxide. Two different species were used as CH 3 radical precursors, azomethane and methyl iodide. The overall rate coefficient of the CH 3 + OH reaction was determined in the temperature range 1081-1426 K under conditions of chemical isolation. The experimental data are in good agreement with a recent theoretical study of the reaction. The decomposition of methanol to methyl and OH radicals was also investigated behind reflected shock waves. The current measurements are in good agreement with a recent experimental study and a master equation simulation. C 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 488-495, 2008

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Recombination of Methyl Radicals. 1. New Data between 1175 and 1750 K in the Falloff Region

Cited by 58 publications

References 52 publications

A shock tube study of methyl‐methyl reactions between 1200 and 2400 K

A shock tube study of methyl‐methyl reactions between 1200 and 2400 K

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

High‐temperature shock tube study of the reactions CH₃ + OH → products and CH₃OH + Ar → products

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Recombination of Methyl Radicals. 1. New Data between 1175 and 1750 K in the Falloff Region

Cited by 58 publications

References 52 publications

A shock tube study of methyl‐methyl reactions between 1200 and 2400 K

A shock tube study of methyl‐methyl reactions between 1200 and 2400 K

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

High‐temperature shock tube study of the reactions CH3 + OH → products and CH3OH + Ar → products

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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

High‐temperature shock tube study of the reactions CH₃ + OH → products and CH₃OH + Ar → products