Kinetic investigation of NCO radicals reacting with selected hydrocarbons

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

Karl H. Becker, Harald Geiger, Frank Schmidt and Peter Wiesen


Abstract

Bimolecular rate coefficients for the reactions of isocyanate radicals (NCO) with ethane (C2H6), allene (C3H4), propene (C3H6), but-1-ene (C4H8) and but-1-yne (C4H6) were measured in argon as carrier gas. NCO radicals have been formed using excimer laser photolysis of chlorine isocyanate (ClNCO) and were detected in their electronic ground state, [X with combining tilde]2Π, by laser-induced fluorescence. The NCO+C2H6 reaction was investigated at 20 Torr total pressure in the temperature range 297–899 K. The reaction exhibits a positive temperature dependence which is well described by the following modified Arrhenius equation: In addition, measurements carried out at 651 K in the pressure range 5–528 Torr showed no pressure dependence, which supports the view that the NCO+C2H6 reaction proceeds as a simple H atom abstraction. For the reaction of NCO radicals with allene (C3H4), propene (C3H6), but-1-ene (C4H8) and but-1-yne (C4H6) bimolecular rate coefficients were determined at room temperature and at 20 Torr total pressure. Additionally, the reactions of NCO with C3H4 and C4H6 were studied at different total pressures. For both reactions, no pressure dependence was observed. The following rate coefficients were obtained at 298 K (in units of 10-11 cm3 s-1): kNCO+C3H4=(1.39±0.18), kNCO+C3H6=(4.29±0.20), kNCO+C4H8=(6.18±0.46) and kNCO+C4H6=(1.41±0.14). A correlation between the measured bimolecular rate coefficients of the NCO reactions with unsaturated hydrocarbons and their ionisation potentials was established.


References

  1. J. A. Miller and C. T. Bowman, Prog. Energy Combust. Sci., 1989, 15, 287 CrossRef CAS.
  2. C. P. Fenimore, Symp. (Int.) Combust., [Proc.], 1971, 13, 373 Search PubMed.
  3. C. T. Bowman, Symp. (Int.) Combust., [Proc.], 1992, 24, 859 Search PubMed.
  4. D. L. Baulch, C. J. Cobos, R. A. Cox, C. Esser, P. Frank, T. Just, J. A. Kerr, M. J. Pilling, J. Troe, R. W. Walker and J. Warnatz, J. Phys. Chem. Ref. Data, 1992, 21, 411 CAS.
  5. K. H. Becker, F. Schmidt and P. Wiesen, Combust. Flame, in the press Search PubMed.
  6. D. L. Siebers and J. A. Caton, Combust. Flame, 1990, 79, 31 CAS.
  7. K. H. Becker, R. Kurtenbach, F. Schmidt and P. Wiesen, Ber. Bunsen-Ges. Phys. Chem., 1997, 101, 128 CAS and references cited therein.
  8. K. H. Becker, R. Kurtenbach and P. Wiesen, J. Phys. Chem., 1995, 99, 5986 CrossRef CAS.
  9. K. H. Becker, R. Kurtenbach, F. Schmidt and P. Wiesen, Chem. Phys. Lett., 1995, 235, 230 CrossRef CAS.
  10. S. Leggett, Atmos. Environ., 1996, 30, 215 CrossRef.
  11. S. Wategaonkar and D. W. Setser, J. Phys. Chem., 1993, 97, 10028 CrossRef CAS.
  12. A. Schuck, H. Volpp and J. Wolfrum, Combust. Flame, 1994, 99, 491 CAS.
  13. R. Kurtenbach, PhD Thesis, University of Wuppertal, 1994.
  14. E. Nachbaur and W. Gottardi, Monatsh. Chem., 1966, 97, 115 CAS.
  15. J. Park and J. F. Hershberger, Chem. Phys. Lett., 1994, 218, 537 CrossRef CAS.
  16. D. L. Yang, T. Yu, N. S. Wang and M. C. Lin, Chem. Phys., 1992, 160, 307 CrossRef CAS.
  17. M. M. Maricq and J. J. Szente, J. Phys. Chem., 1994, 98, 2078 CrossRef CAS.
  18. J. S. Pilgrim, A. McIlroy and C. A. Taatjes, J. Phys. Chem. A, 1997, 101, 1873 CrossRef CAS.
  19. P. W. Seakins, M. J. Pilling, J. T. Niiranen, D. Gutman and L. N. Krasnoperov, J. Phys. Chem., 1992, 96, 9847 CrossRef CAS.
  20. J. H. Knox and R. G. Musgrave, Trans. Faraday Soc., 1967, 63, 2201 RSC.
  21. R. A. Perry, Symp. (Int.) Combust., [Proc.], 1998, 21, 913 Search PubMed.
  22. A. Liu, W. A. Mulac and C. D. Jonah, J. Phys. Chem., 1998, 92, 131 Search PubMed.
  23. M. T. Butterficld, T. Yu and M. C. Lin, Chem. Phys., 1993, 169, 129 CrossRef.
  24. T. J. Wallington, L. M. Skewes and W. O. Siegl, J. Photochem. Photobiol., A, 1988, 45, 167 CrossRef CAS.
  25. O. J. Nielsen, O. Jorgensen, M. Donlon, H. W. Sidebottom, D. J. O'Farrell and J. Treacy, Chem. Phys. Lett., 1990, 168, 319 CrossRef CAS.
  26. I. R. Sims, J.-L. Queffelec, D. Travers, B. R. Rowe, L. B. Herbert, J. Karthauser and I. W. M. Smith, Chem. Phys. Lett., 1993, 211, 461 CrossRef CAS.
  27. R. K. Pearson, J. O. Cowles, G. L. Hermann, D. W. Gregg and J. R. Creighton, IEEE J. Quantum Electron., 1973, 9, 879 CAS.
  28. I. Barnes, V. Bastian, K. H. Becker, R. Overath and Z. Tong, Int. J. Chem. Kinet., 1989, 21, 499 CrossRef CAS.
  29. D. M. Golden, A. S. Rodgers and S. W. Benson, J. Am. Chem. Soc., 1966, 88, 3196 CrossRef CAS.
  30. R. Atkinson and S. M. Aschmann, Int. J. Chem. Kinet., 1984, 16, 1175 CrossRef CAS.
  31. S. W. Benson, A. N. Bose and P. Nangia, J. Am. Chem. Soc., 1963, 85, 1388 CrossRef CAS.
  32. R. B. Boodaghians, I. W. Hall, F. S. Toby and R. P. Wayne, J. Chem. Soc., Faraday Trans. 2, 1987, 83, 2073 RSC.
Click here to see how this site uses Cookies. View our privacy policy here.