Experimental Study of the Rate of OH + HO2 → H2O + O2 at High Temperatures Using the Reverse Reaction

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• 作者：Zekai Hong ; Subith S. Vasu ; David F. Davidson ; Ronald K. Hanson
• 刊名：Journal of Physical Chemistry A
• 出版年：2010
• 出版时间：May 6, 2010
• 年：2010
• 卷：114
• 期：17
• 页码：5520-5525
• 全文大小：210K
• 年卷期：v.114,no.17(May 6, 2010)
• ISSN：1520-5215

文摘

The rate constant of the reaction OH + HOb>2b> → Hb>2b>O + Ob>2b> (1) can be inferred at high temperatures from measurements of the rate of its reverse reaction Hb>2b>O + Ob>2b> → OH + HOb>2b> (−1). In this work, we used laser absorption of both Hb>2b>O and OH to study the reverse reaction in shock-heated Hb>2b>O/Ob>2b>/Ar mixtures over the temperature range 1600−2200 K. Initial Hb>2b>O concentrations were determined using tunable diode laser absorption near 2.5 μm, and OH concentration time-histories were measured using UV ring dye laser absorption near 306.7 nm. Detailed kinetic analysis of the OH time-history profiles yielded a value for the rate constant kb>1b> of (3.3 ± 0.9) × 10¹³ [cm³ mol⁻¹ s⁻¹] between 1600 and 2200 K. The results of this study agree well with those reported by Srinivasan et al. (Srinivasan, N.K.; Su, M.-C.; Sutherland, J.W.; Michael, J.V.; Ruscic, B. J. Phys. Chem. A <b>2006b>, 110, 6602−6607) in the temperature regime between 1200 and 1700 K. The combination of the two studies suggests only a weak temperature dependence of kb>1b> above 1200 K. Data from the current study and that of Keyser (Keyser, L.F. J. Phys. Chem. <b>1988b>, 92, 1193−1200) at lower temperatures can be described by the kb>1b> expression proposed by Baulch et al. (Baulch, D.L.; Cobos, C.J.; Cox, R.A.; Esser, C.; Frank, P.; Just, Th.; Kerr, J.A.; Pilling, M.J.; Troe, J.; Walker, R.W.; Warnatz, J. J. Phys. Chem. Ref. Data <b>1992b>, 21, 411), kb>1b> = 2.89 × 10¹³ exp(252/T) [cm³ mol⁻¹ s⁻¹]. However, it should be noted that some previous studies suggest a kb>1b> minimum around 1250 K (Hippler, H.; Neunaber, H.; Troe, J. J. Chem. Phys. <b>1995b>, 103, 3510−3516) or 1000 K (Kappel, C.; Luther, K.; Troe, J. Phys. Chem. Chem. Phys. <b>2002b>, 4, 4392−4398).