Yield of Formyl Radical from the Vinyl + O2 Reaction. Issue 5 (9th October 2013)

• Record Type: Journal Article
• Authors: Matsugi, Akira; Miyoshi, Akira
• Is Part Of: International journal of chemical kinetics. Volume 46:Issue 5(2014:May)
• Page Start: 260
• Page End: 274
• Publication Date: 2013-10-09
• Subjects: Chemical kinetics -- Periodicals; 541.394
• DOI: 10.1002/kin.20823
• Languages: English
• ISSNs: 0538-8066

Abstract

<abstract abstract-type="main"> <title>ABSTRACT</title> <p>The yield of formyl (HCO) radical from the reaction of vinyl (C<sub>2</sub>H<sub>3</sub>) radical with O<sub>2</sub> has been investigated by using a pulsed laser photolysis/cavity ring‐down spectroscopy technique at room temperature. The rate constants for the C<sub>2</sub>H<sub>3</sub> + O<sub>2</sub> and HCO + O<sub>2</sub> reactions were measured to be (8.60 ± 0.87) × 10<sup>−12</sup> and (5.55 ± 1.00) × 10<sup>−12</sup> cm<sup>3</sup> molecule<sup>−1</sup> s<sup>−1</sup>, respectively, which were consistent with preceding studies. The yield of HCO radical was determined to be <italic>ϕ</italic>(HCO) = 0.222 ± 0.066, and it was independent of pressure in the pressure range 10–100 Torr with He or N<sub>2</sub> 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 C<sub>2</sub>H<sub>3</sub> + O<sub>2</sub> 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 C<sub>2</sub>H<sub>3</sub> + O<sub>2</sub> 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.</p> </abstract>