IUPAC Subcommittee on Gas Kinetic Data Evaluation

Providing evaluated kinetic data on the web since 1999.

IUPAC Subcommittee on Gas Kinetic Data Evaluation

Website: http://www.iupac-kinetic.ch.cam.ac.uk/ See website for latest evaluated data. Datasheets can be downloaded for personal use only and must not be retransmitted or disseminated either electronically or in hardcopy without explicit written permission.

This datasheet last evaluated: 2001-10-02 ; last change in preferred values: 2001-10-02 ; last peer-reviewed publication: 2004-03-09


HO2 + HO2H2O2 + O2 (1) Δ Hοnot given
HO2 + HO2 + MH2O2 + O2 + M(2) Δ Hοnot given

Rate Coefficient Data

Absolute Rate Coefficients

Rate Coefficient (k) / Temperature / ReferenceTechniques and Comments
cm3molecule-1s-1Kelvin
3.8×10 -14 exp[(1250±200)/T]273–339Cox and Burrows, 1979MM (a)
(2.35 ± 0.2)×10 -12 298
2.4×10 -13 exp[(560±200)/T]298–359Thrush and Tyndall, 1982aFP-TDLS (b)
(1.6 ± 0.1)×10 -12 298
2.5×10 -12 (1.013 bar N 2 )296Simonaitis and Heicklen, 1982FP-UVA
k 1 = (1.4 ± 0.2)×10 -12 296
k 1 = 2.2×10 -13 exp(620/T)230–420Kircher and Sander, 1984FP-UVA (c)
k 1 = (1.7 ± 0.22)×10 -12 298
k 2 = 1.9×10 -33 [N 2 ] exp(980/T)230–420Kircher and Sander, 1984FP-UVA (c)
k 2 = (5.4 ± 3.1)×10 -32 [N 2 ]298
k 1 = 1.88×10 -12 298Kurylo et al., 1986FP-UVA (d)
k 2 = 4.53×10 -32 [O 2 ]298
k 2 = 5.95×10 -32 [N 2 ]298
k 1 = 2.0×10 -13 exp[(595±120)/T]253–390Takacs and Howard, 1986DF-LMR
k 1 = (1.54 ± 0.07)×10 -12 294
(3.3 ± 0.9)×10 -12 298Lightfoot et al., 1988FP-UVA
(1.5 ± 0.5)×10 -12 418
(8.8 ± 1.2)×10 -13 577
(8.2 ± 2.0)×10 -13 623
(8.1 ± 1.5)×10 -13 677
(7.6 ± 1.4)×10 -13 723
(9.1 ± 2.5)×10 -13 777
(2.44±0.20)×10 -12 (1000 mbar O 2 )298Crowley et al., 1991MMS
(2.84±0.30)×10 -12 (1000 mbar N 2 )298
(3.5±1.0)×10 -12 (1000 mbar SF 6 )295Sehested et al., 1997PR-UVA

Comments

(a) HO 2 radicals were monitored by molecular modulation spectrometry. The data cited refer to a total pressure of 1013 mbar and absence of H 2 O.

(b) HO 2 radicals were monitored by diode laser spectroscopy. Pressure = 9–27 mbar (7–20 Torr) of O 2 .

(c) Pressure range was 0.133–0.933 bar (100–700 Torr) of Ar and N 2 . Enhancement of k by added water was observed, in a linear fashion independent of the pressure of other gases, according to the equation k obs =k×(1 + 1.4×10 -21 exp(2200/T) [H 2 O]).

(d) Total pressure range was 0.033–1.01 bar (25–760 Torr).

Preferred Values

k1cm3molecule-1s-11.6-121.6×10-12±0.15  if   T 298 k2cm3molecule-1s-1{5.2-32 N_2[N2] 5.2×10-32 ±0.15 N_2[N2]   if   T 298 4.5-32 O_2[O2] 4.5×10-32 O_2[O2]   if   T 298 k1cm3molecule-1s-1{1.6-121.6×10-12±0.15  if   T 298 2.2-13PlusMinus 600200 T2.2×10-13exp( 600±200)/T  if   230 T 420 k2cm3molecule-1s-1{5.1-32 N_2[N2] 5.1×10-32±0.15 N_2[N2]   if   T 298 1.9-33PlusMinus 980300 T N_2[N2]1.9×10-33exp( 980±300)/T N_2[N2]  if   230 T 420

where [H 2 O] is in molecule cm -3 units.

Comments on Preferred Values

The preferred values given here are identical with the values derived by Kircher and Sander (1984) and also recommended in the review by Wallington et al. (1992).

At temperatures close to 298 K, the reaction proceeds by two channels, one bimolecular and the other termolecular. The preferred values for k 1 are based on the work of Cox and Burrows (1979), Thrush and Tyndall (1982a), Kircher and Sander (1984), Kurylo et al. (1986), Takacs and Howard (1986) and Lightfoot et al. (1988). The work of Kurylo et al. (1986) and of Lightfoot et al. (1988) has confirmed quantitatively the effects of pressure previously observed by Simonaitis and Heicklen (1982) and Kircher and Sander (1984). The recommendations for k 2 are based on the work of Kircher and Sander (1984) and Kurylo et al. (1986), with the temperature coefficient of k 2 being taken from Kircher and Sander (1984) and Lightfoot et al. (1988). At higher temperatures, T>600 K, Hippler et al. (1990) and Lightfoot et al. (1988) observe a sharp change in the temperature coefficient with upward curvature of the Arrhenius plot.

The marked effect of water on this reaction was established in the work of Lii et al. (1981) and Kircher and Sander (1984). The recommended multiplying factor for k 1 and k 2 in the presence of water is based on these two studies.

Mozurkewich and Benson (1985) have considered the HO 2 + HO 2 reaction theoretically and conclude that the negative temperature dependence, the pressure dependence, and the observed isotope effects can most reasonably be explained in terms of a cyclic hydrogen bonded, HO 2 O 2 H, intermediate to alternative structures suggested by others.

Sahetchian et al. (1982) reported the formation of H 2 (10% at 500 K) in the reaction system but this is contrary to earlier evidence of Baldwin et al. (1984) and the more recent and careful study of Stephens et al. (1989), who find less than 0.01 fractional contribution from the channel leading to H 2 + 2O 2 . Keyser et al. (1985) have measured a yield of O 2 (b 1 Σ) of <3×10 -2 per HO 2 consumed.

References

  • Baldwin, R. R., Dean, C. E., Honeyman, M. R. and Walker, R. W. , J. Chem. Soc. Faraday 1 , 80 , 3187 , 1984.
  • Cox, R. A. and Burrows, J. P. , J. Phys. Chem. , 83 , 2560 , 1979.
  • Crowley, J. N., Simon, F. G., Burrows, J. P., Moortgat, G. K., Hippler, H., Troe, J. and Willner, J , J. Chem. Phys. , 93 , 1755 , 1990.
  • Jenkin, M. E. and Cox, R. A. , Chem. , 60 , 1 , 1991.
  • Keyser, L. F, Choo, K. Y. and Leu, M. T. , Int. J. Chem. Kinet. , 17 , 1169 , 1985.
  • Kircher, C. C. and Sander, S. P. , J. Phys. Chem. , 88 , 2082 , 1984.
  • Kurylo, M. J., Ouellette, P. A. and Laufer, A. H. , J. Phys. Chem. , 90 , 437 , 1986.
  • Lightfoot, P. D., Veyret, B. and Lesclaux, R. , Chem. Phys. Lett. , 150 , 120 , 1988.
  • Lii, R. -R. , Sauer Jr., M. C. and Gordon, S. , J. Phys. Chem. , 85 , 2833 , 1981.
  • Mozurkewich, M. and Benson, S. W. , Int. J. Chem. Kinet. , 17 , 787 , 1985.
  • Sahetchian, K. A., Heiss, A. and Rigny, R. , Can. J. Chem. , 60 , 2896 , 1982.
  • Sander, S. P. , J. Phys. Chem. , 88 , 6018 , 1984.
  • Sander, S. P., Peterson, M., Watson, R. T. and Patrick, R. , J. Phys. Chem. , 86 , 1236 , 1982.
  • Sehested, J., Mogelberg, T., Fagerstrom, K., Mahmoud, G. and Wallington, T. J. , Int. J. Chem. Kinet. , 29 , 673 , 1997.
  • Simonaitis, R. and Heicklen, J. , J. Phys. Chem. , 86 , 3416 , 1982.
  • Stephens, S. L., Birks, J. W. and Glinski, R. J. , J. Phys. Chem. , 93 , 8384 , 1989.
  • Takacs, G. A. and Howard, C. J. , J. Phys. Chem. , 90 , 687 , 1986.
  • Thrush, B. A. and Tyndall, G. S. , Chem. Phys. Lett. , 92 , 232 , 1982a.
  • Thrush, B. A. and Tyndall, G. S. , J. Chem. Soc. Faraday Trans. 2 , 78 , 1469 , 1982b.
  • Wallington, T. J., Dagaut, P. and Kurylo, M. J. , Chem. Rev. , 92 , 667 , 1992.