View PDF Version
 
DOI: 10.1039/A708536B (Paper) Reference Section for: J. Chem. Soc., Faraday Trans., 1998, 94, 1203-1210

Formation of HO2 from OH and C2H2 in the presence of O2

(Note: The full text of this document is currently only available in the PDF Version )

Birger Bohn and Cornelius Zetzsch

Abstract

Pulsed production of OH in a gas-phase system containing acetylene, O2 and NO resulted in biexponential OH-decay curves, indicating formation of HO2 in secondary reactions. Production and detection of OH were performed by 248 nm photolysis of H2O2 and cw-laser long-path absorption at 308 nm, respectively. Measurements were made at room temperature in O2 or N2–O2 mixtures containing 5% O2 at total pressures between 10 and 100 kPa. Analysis of the decay curves resulted in effective rate constants for the removal of OH and the formation of HO2 by acetylene in the presence of O2 in the range (1.4–3.5)×10-13 cm3 s-1, dependent on total pressure and O2 concentration. HO2 is thought to be formed from HCO and O2, with HCO originating in a reaction of an intermediate acetylene–OH adduct with O2. HO2 yields were found to vary between 1.13 and 1.01 and tending to higher values at lower total pressures. These yields are higher than the expected value of 1, which can be explained by a dissociation of a small fraction of vibrationally excited glyoxal formed, together with OH in a second channel of the acetylene–OH adduct+O2 reaction. In order to check whether the increased HO2 yields are real, CO was used instead of acetylene. In this case, an HO2 yield of 0.99 was found, in good agreement with expectations, and a rate constant of (1.66±0.25)×10-13 cm3 s-1 for the OH+CO reaction in 20 kPa O2 was determined. In addition, a rate constant for the HO2+NO reaction of (9.5±1.5)×10-12 cm3 s-1, rate constants for the OH+NO reaction in the range (1.3–7.4)×10-12 cm3 s-1, depending on total pressure, and upper limits for the rate constants of possible reactions HO2+C2H2 (k⩽5×10-15 cm3 s-1) and HO2+CO (k⩽3×10-15 cm3 s-1) were derived. Error limits include statistical (2σ) and possible systematic errors.

References

  1. R. Atkinson, J. Phys. Chem. Ref. Data, Monograph 1, 1989, 121 Search PubMed.
  2. R. A. Perry, R. Atkinson and J. N. Pitts Jr., J. Chem. Phys., 1977, 67, 5577 CrossRef CAS.
  3. J. V. Michael, D. F. Nava, R. P. Borkowski, W. A. Payne and L. J. Stief, J. Chem. Phys., 1980, 73, 6108 CrossRef CAS.
  4. R. A. Perry and D. Williamson, Chem. Phys. Lett., 1982, 93, 331 CrossRef CAS.
  5. G. P. Smith, P. W. Fairchild and D. R. Crosley, J. Chem. Phys., 1984, 81, 2667 CrossRef CAS.
  6. J. A. Miller and C. F. Melius, in Twenty-Second Symposium (International) on Combustion, The Combustion Institute, Pittsburgh, PA, 1988, p. 1031 Search PubMed.
  7. V. Schmidt, G.-Y. Zhu, K. H. Becker and E. H. Fink, in Physico-Chemical Behaviour of Atmospheric Pollutants, ed. B. Versino and G. Angeletti, Reidel, Dordrecht, 1984, p.177 Search PubMed.
  8. A. Wahner, Dissertation, Universität Bochum, 1984.
  9. A. Wahner and C. Zetzsch, Ber. Bunsen-Ges. Phys. Chem., 1985, 89, 323 Search PubMed.
  10. V. Schmidt, G. Y. Zhu, K. H. Becker and E. H. Fink, Ber. Bunsen-Ges. Phys. Chem., 1985, 89, 321 Search PubMed.
  11. E. H. Fink and V. Schmidt, Bericht Nr. 8, Fachbereich 9, Universität Wuppertal, 1985.
  12. M. Siese and C. Zetzsch, Z. Phys. Chem., 1995, 188, 75 CAS.
  13. B. Bohn, M. Siese and C. Zetzsch, J. Chem. Soc., Faraday Trans., 1996, 92, 1459 RSC.
  14. Z. Y. Zhang and J. Peeters, in Physico-Chemical Behaviour of Atmospheric Pollutants, ed. Restelli and G. Angeletti, Kluwer Academic Publishers, Dordrecht, 1990, p. 377 Search PubMed.
  15. J. R. Kanofsky, D. Lucas, F. Pruss and D. Gutman, J. Phys. Chem., 1974, 78, 311 CrossRef CAS.
  16. W. Hack, K. Hoyermann, R. Sievert and H. Gg. Wagner, Oxid. Commun., 1983, 5, 101 Search PubMed.
  17. S. Hatakeyama, N. Washida and H. Akimoto, J. Phys. Chem., 1986, 90, 173 CrossRef CAS.
  18. B. Bohn and C. Zetzsch, J. Phys. Chem., 1997, 101, 1488 Search PubMed.
  19. W. B. DeMore, S. P. Sander, D. M. Golden, R. F. Hampson, M. J. Kurylo, C. J. Howard, A. R. Ravishankara, C. E. Kolb and M. J. Molina, in Chemical Kinetics and Photochemical Data for Use in Stratospheric Modeling, Evaluation Number 12; JPL Publication 97-4, Jet Propulsion Laboratory, Pasadena 1997, and references therein Search PubMed.
  20. A. Wahner and C. Zetzsch, J. Phys. Chem., 1983, 87, 4945 CrossRef CAS.
  21. R. Atkinson, D. L. Baulch, R. A. Cox, R. F. Hampson Jr., J. A. Kerr, M. J. Rossi and J. Troe, J. Phys. Chem. Ref. Data, 1997, 26, 577; 580; 617.
  22. J. D. Cox and G. Pilcher, in Thermochemistry of Organic and Organometallic Compounds, Academic Press, London, 1970 Search PubMed.
  23. C. Zetzsch and C. Leonard, in Proc. EUROTRAC Symposium '90, ed. P. Borrell, P. M. Borrell and W. Seiler, SPB Academic, The Hague, 1991, p. 483 Search PubMed.
  24. M. Elend and C. Zetzsch, in Proc. 1st Workshop of the EUROTRAC-2 Subproject Chemical Mechanism Development (CMD), ed. M. Ammann and R. Lorenzen, ETH-Zürich/Paul Scherrer Institute, Villigen, 1997, p. 135 Search PubMed.
Click here to see how this site uses Cookies. View our privacy policy here.