Forskning ved Københavns Universitet - Københavns Universitet


Atmospheric chemistry of acetone: Kinetic study of the CH3C(O)CH2O2 + NO/NO2 reactions and decomposition of CH3C(O)CH2O2NO2

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  • Jens Sehested
  • Lene K. Christensen
  • Nielsen, Ole John
  • Merete Bilde
  • Timothy I. Wallington
  • William F. Schneider
  • John J. Orlando
  • Geoffrey S. Tyndall

Pulse radiolysis was used to study the kinetics of the reactions of CH3C(O)CH2O2 radicals with NO and NO2 at 295 K. By monitoring the rate of formation and decay of NO2 using its absorption at 400 and 450 nm the rate constants k(CH3C(O)CH2O2 + NO) = (8 ± 2) × 10-12 and k(CH3C(O)CH2O2 + NO2) = (6.4 ± 0.6) × 10-12 cm3 molecule-1 s-1 were determined. Long path length Fourier transform infrared spectrometers were used to investigate the IR spectrum and thermal stability of the peroxynitrate, CH3C(O)CH2O2NO2. A value of k-6 ≈ 3 s-1 was determined for the rate of thermal decomposition of CH3C(O)CH2O2NO2 in 700 torr total pressure of O2 diluent at 295 K. When combined with lower temperature studies (250-275 K) a decomposition rate of k-6 = 1.9 × 1016 exp (- 10830/T) s-1 is determined. Density functional theory was used to calculate the IR spectrum of CH3C(O)CH2O2NO2. Finally, the rate constants for reactions of the CH3C(O)CH2 radical with NO and NO2 were determined to be k(CH3C(O)CH2 + NO) = (2.6 ± 0.3) × 10-11 and k(CH3C(O)CH2 + NO2) = (1.6 ± 0.4) × 10-11 cm3 molecule-1 s-1. The results are discussed in the context of the atmospheric chemistry of acetone and the long range atmospheric transport of NOx.

TidsskriftInternational Journal of Chemical Kinetics
Udgave nummer7
Sider (fra-til)475-489
Antal sider15
StatusUdgivet - 1 jan. 1998

ID: 225752878