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Yield of Formyl Radical from the Vinyl + O2 Reaction

Authors

  • Akira Matsugi,

    1. Department of Chemical System Engineering, School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
    2. Research Institute of Science for Safety and Sustainability, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, Japan
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  • Akira Miyoshi

    Corresponding author
    1. Department of Chemical System Engineering, School of Engineering, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
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  • Contract grant sponsor: Japan Society for the Promotion of Science, Japan.

  • This article was published online on 9 October 2013. An error was subsequently identified. This notice is included in the online and print versions to indicate that both have been corrected 13 November 2013.

ABSTRACT

The yield of formyl (HCO) radical from the reaction of vinyl (C2H3) radical with O2 has been investigated by using a pulsed laser photolysis/cavity ring-down spectroscopy technique at room temperature. The rate constants for the C2H3 + O2 and HCO + O2 reactions were measured to be (8.60 ± 0.87) × 10−12 and (5.55 ± 1.00) × 10−12 cm3 molecule−1 s−1, respectively, which were consistent with preceding studies. The yield of HCO radical was determined to be ϕ(HCO) = 0.222 ± 0.066, and it was independent of pressure in the pressure range 10–100 Torr with He or N2 buffer. The Rice–Ramsperger–Kassel–Marcus calculation combined with a prior energy distribution model could reproduce the experimental HCO-radical yield and indicated that a significant portion of HCO radicals formed in the C2H3 + O2 reaction promptly dissociated to H + CO. The first CO-stretch excited state of HCO radical, HCO(0,0,1), was observed at the total pressure of 1 Torr; the time profiles of which were satisfactory reproduced by a kinetic simulation including the relaxation of hot HCO radicals. These experimental, theoretical, and modeling results provide solid evidence for the prompt dissociation of hot HCO radicals formed in the C2H3 + O2 reaction. The product-specific rate constants that extrapolated to higher temperature and wider pressure ranges are presented. Implications of the suggested mechanism for combustion modeling are also discussed.

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