552
GIERCZAK ET AL.
by Ninomiya et al. [28] and k11(298 K) = (7.1 0.6) ×
10−12 cm3 molecule−1 s−1 by Timonen et al. [29].
Timonen et al. found no temperature dependence over
the range 296–582 K, E/R = 36 241 K−1; hence,
reaction (11) is a barrierless reaction similar to re-
action (2). The two available relative rate studies of
reaction (11) [28,30] yield k11(296 K) values in fair
agreement, about 10% lower, with the values obtained
by the absolute methods. The rate coefficient for reac-
tion (11) is approximately a factor of 4 smaller than
k2(296 K) as qualitatively expected from the IP corre-
lation.
5. Khamaganov, V.; Karunanandan, R.; Rodriguez, A.;
Crowley, J. N. Phys Chem Chem Phys 2007, 9, 4098–
4113.
6. Somnitz, H.; Fida, M.; Ufer, T.; Zellner, R. Phys Chem
Chem Phys 2005, 7, 3342–3352.
7. Blitz, M. A.; Heard, D. E.; Pilling, M. J. Chem Phys Lett
2002, 365, 374–379.
8. Tyndall, G. S.; Orlando, J. J.; Kegley-Owen, C. S.;
Wallington, T. J.; Hurley, M. D. Int J Chem Kinet 1999,
31, 776–784.
9. Tyndall, G. S.; Orlando, J. J.; Wallington, T. J.; Hurley,
M. D. Int J Chem Kinet 1997, 29, 655–663.
10. Timonen, R. S.; Gutman, D. J Phys Chem 1986, 90,
2987–2991.
11. Slagle, I. R.; Gutman, D. J Am Chem Soc 1982, 104,
4741–4748.
12. Kaiser, E. W.; Wallington, T. J. J Phys Chem 1995, 99,
8669–8672.
13. Maricq, M. M.; Szente, J. J. Chem Phys Lett 1996, 253,
333–339.
The rate coefficient for the reaction
CF3CO + Cl2 → CF3C(O)Cl + Cl
(12)
was reported to be k12 = (6.1 2.5) × 10−13 cm3
molecule−1 s−1 and independent of temperature over
the range 223–353 K [31]. The rate coefficient for re-
action (12) is also much smaller than k2(296 K) as
expected. k12 is, however, also much smaller than k11,
implying that physical properties other than the IP of
molecules play a role in determining the rate coefficient
for this reaction [32].
14. Rajakumar, B.; Flad, J. E.; Gierczak, T.; Ravishankara,
A. R.; Burkholder, J. B. J Phys Chem A 2007, 111,
8950–8958.
15. Rajakumar, B.; Gierczak, T.; Flad, J. E.; Ravishankara,
A. R.; Burkholder, J. B. J Photochem Photobiol A: Chem
2008, 199, 336–344.
16. O’Keefe, A.; Deacon, D. A. G. Rev Sci Inst 1988, 59,
2544–2551.
CONCLUSION
17. Sander, S. P.; Friedl, R. R.; Golden, D. M.; Kurylo, M. J.;
Moortgat, G. K.; Wine, P. H.; Ravishankara, A. R.; Kolb,
C. E.; Molina, M. J.; Finlayson-Pitts, B. J.; Huie, R.
E.; Orkin, V. L. Chemical Kinetics and Photochemical
Data for Use in Atmospheric Studies; Jet Propulsion
Laboratory: Pasadena, CA, 2006; JPL Pub. No. 06-2.
18. Brown, S. S.; Ravishankara, A. R.; Stark, H. J Phys
Chem A 2000, 104, 7044–7052.
19. Gierczak, T.; Burkholder, J. B.; Bauerle, S.;
Ravishankara, A. R. Chem Phys 1998, 231, 229–
244.
20. Horowitz, A.; Meller, R.; Moortgat, G. K. J Photochem
Photobiol A: Chem 2001, 146, 19–27.
21. Cuevas, C. A.; Notario, A.; Martinez, E.; Albaladejo, J.
Phys Chem Chem Phys 2004, 6, 2230–2236.
22. Lightfoot, P. D.; Kirwan, S. P.; Pilling, M. J. J Phys
Chem 1988, 92, 4938–4946.
23. Maricq, M. M.; Ball, J. C.; Straccia, A. M.; Szente, J. J.
Int J Chem Kinet 1997, 29, 421–429.
24. Atkinson, R.; Baulch, D. L.; Cox, R. A.; Crowley, J. N.;
Hampson, R. F.; Hynes, R. G.; Jenkin, M. E.; Rossi,
M. J.; Troe, J. Atmos Chem Phys Discuss 2005, 5, 6295–
7168.
25. Paltenghi, R.; Ogryzlo, E. A.; Bayes, K. D. J Phys Chem
1984, 88, 2595–2599.
Rate coefficients for the gas-phase reaction of the
acetyl radical with Cl2 have been measured un-
der pseudo-first-order conditions in CH3CO be-
tween 253 and 384 K at 55–200 Torr (He) to be
k2(T ) = (2.2 0.8) × 10−11 exp[(85 120)/T ] cm3
molecule−1 s−1 where the error limits are 2σ and in-
clude estimated systematic errors. The reaction is effi-
cient, independent of pressure, and nearly temperature
independent (within the range of pressures and temper-
atures used in this work). The rate coefficients obtained
in this work are consistent with but more accurate than
obtained in previous studies, primarily due to the iso-
lation of reaction (2) under conditions that avoided
complications due to secondary CH3CO chemistry.
BIBLIOGRAPHY
1. McKeen, S. A.; Gierczak, T.; Burkholder, J. B.;
Wennberg, P. O.; Hanisco, T. F.; Keim, E. R.; Gao, R.-S.;
Liu, S. C.; Ravishankara, A. R.; Fahey, D. W. Geophys
Res Lett 1997, 24, 3177–3180.
2. Blitz, M. A.; Heard, D. E.; Pilling, M. J. J Phys Chem
A 2006, 110, 6742–6756.
3. Cameron, M.; Sivkumaran, V.; Dillon, T. J.; Crowley, J.
N. Phys Chem Chem Phys 2002, 4, 3628–3638.
4. Emrich, M.; Warneck, P. J Phys Chem A 2000, 104,
9436–9442.
26. Lias, S. G.; Bartmess, J. E.; Liebman, J. F.; Holmes,
J. L.; Levin, R. D.; Mallard, W. J Phys Chem Ref 1988,
17(Suppl. 1), 1–861.
27. Anand, S.; Zamari, M. M.; Menkir, G.; Levis, R. J.;
Schlegel, H. B. J Phys Chem 2004, 108, 3162–
3165.
International Journal of Chemical Kinetics DOI 10.1002/kin