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: 2004-03-09 ; last change in preferred values: 2001-07-16 ; last peer-reviewed publication: 2004-03-09


HO2NO2 + MHO2 + NO2 + M(1) Δ Hο = 100.5 kJ mol-1

Rate Coefficient Data: Low-pressure rate coefficients

Absolute Rate Coefficients

Rate Coefficient (k0) / Temperature / ReferenceTechniques and Comments
s-1Kelvin
1.5×10 -20 [N 2 ]298Cox and Patrick, 1979(a)
5.2×10 -6 exp[-(10014±250)/T] [N 2 ]261–295Graham et al., 1978(b)
1.3×10 -20 [N 2 ]298
4.1×10 -5 exp[-(10645±260)/T] [N 2 ]261–307Zabel, 1995(c)
1.2×10 -20 [N 2 ]298

Comments

(a) Derived from measurements of the reverse reaction. Conversion of the data to the dissociation reaction of HO 2 NO 2 using the equilibrium constant K c = 1.68×10 28 exp(-11977/T) cm 3 molecule -1 from Uselman et al. (1978) and comparison with earlier dissociation data.

(b) FTIR study in a 5800 L chamber. Measurements were made at 1.3–9.3 mbar (1–7 Torr) of N 2 . At higher pressures (9.3 mbar), deviations from low pressure behavior were observed.

(c) FTIR study in a 420 L chamber. The pressure range was 14–1027 mbar (10–772 Torr). The falloff curve was evaluated with F c = 0.5.

Preferred Values

k0s-1{1.3-20 N_2[N2] 1.3×10-20 ±0.3 N_2[N2]   if   T 298 4.1-5PlusMinus -10650500 T N_2[N2]4.1×10-5exp( -10650±500)/T N_2[N2]  if   260 T 300

Comments on Preferred Values

The preferred values are from the study of Zabel (1995), and are in close agreement with those from Graham et al. (1978). The data from Zabel (1995) provide the most consistent picture of all RO 2 NO 2 dissociation reactions. Falloff curves are constructed with F c = 0.5.

Rate Coefficient Data: High-pressure rate coefficients

Absolute Rate Coefficients

Rate Coefficient (k) / Temperature / ReferenceTechniques and Comments
s-1Kelvin
>0.018278Graham et al., 1978(a)
5.7×10 15 exp(-11170/T)261–307Zabel, 1995(b)
0.30298

Comments

(a) See comment (b) for k 0 . This is a lower limit since a linear Lindemann-Hinshelwood evaluation of the falloff curve was made for the pressure range 0.013–1.01 bar (10–760 Torr) of N 2 .

(b) See comment (c) for k 0 .

Preferred Values

ks-1{ 0.25 ×10±0.5  if   T 298 4.815PlusMinus -11170500 T4.8×1015exp( -11170±500)/T  if   260 T 300

Comments on Preferred Values

See Comments on Preferred Values for k 0 . The data from Zabel (1995) were re-evaluated with F c = 0.6 such as used for the falloff curves of the reverse reaction HO 2 + NO 2 + M HO 2 NO 2 + M and because F c is identical for the forward and backward reaction. Since the measurements from Zabel (1995) were made close to the low pressure limit, only the extrapolation to k is noticeably influenced by the change of the used F c .

References

  • Cox, R. A. and Patrick, K. , Int. J. Chem. Kinet. , 11 , 635 , 1979.
  • Graham, R. A., Winer, A. M. and Pitts Jr., J. N. , Chem. Phys. Lett., 51, 215 (1977); J. Chem. Phys., 68, 4505 , 1978.
  • Uselman, W. M., Levine, S. Z., Chan, W. H., Calvert, J. G. and Shaw, J. H. , Chem. Phys. Lett. , 58 , 437 , 1978.
  • Zabel, F. , Z. Phys. Chem. , 188 , 119 , 1995.