The absorption cross sections of cf₃o₂, chf₂o₂ and CF₂O radicals

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Resumo

An investigation of photolysis of CHF₂Br, CF₃Br and CF₂ClBr in a mixture with oxygen was carried out at T = 298 K when the mixture was irradiated with a mercury lamp with a maximum radiation at a wavelength of λ = 253.7 nm. Absorption spectra were recorded in the range of 200–900 nm on a Specord M-40 spectrophotometer. The kinetics of photolysis was investigated by the consumption of the initial refrigerant and the accumulation of molecular bromine. The kinetic curves of changes in optical density depending on the irradiation time for CHF₂Br and CF₃Br refrigerants at wavelengths of 214, 224 and 240 nm had inflection points. This effect is explained by the accumulation of RO₂radicals, which in this region of the spectrum absorb UV radiation much more strongly than the original refrigerants. The coordinates of the inflection points made it possible to calculate the absorption cross sections of CF₃O₂ and CHF₂O₂ radicals at wavelengths of 214, 224 and 240 nm. For CF₂ClBr freon, the optical density at a wavelength of 222 nm decreased linearly during the entire irradiation time in accordance with the linear accumulation of photolysis products – BrCl and CF₂O. This allowed us to estimate the upper limit of the absorption cross-section of the CF₂O photolysis product.

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Sobre autores

I. Larin

Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences

Email: eltrofimova@yandex.ru
Rússia, Moscow

T. Belyakova

Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences

Email: eltrofimova@yandex.ru
Rússia, Moscow

G. Pronchev

Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences

Email: eltrofimova@yandex.ru
Rússia, Moscow

E. Trofimova

Semenov Federal Research Center for Chemical Physics, Russian Academy of Sciences

Autor responsável pela correspondência
Email: eltrofimova@yandex.ru
Rússia, Moscow

Bibliografia

  1. Larin I.K., Belyakova T.I., Messineva N.A. et al. // Russ. J. Phys. Chem. B 2021. V. 15. № 5. P. 795. https://doi.org/10.1134/S1990793121050195
  2. Noto T., Babushok V., Hamins A. et al. // Combust. and Flame. 1998. V. 112. № 1–2. P. 147. https://doi.org/10.1016/S0010-2180(97)81763-4
  3. Papanastasiou D.K., Carlon N.R., NEᵤman J.A. et al. // Geophys. Res. Lett. 2013. V. 40. № 2. P. 464. https://doi.org/10.1002/grl.50121
  4. Montreal Protocol on Substances that Deplete the Ozone Layer. United Nations Environment Programme (UNEP). Montreal: Halons Technical Options Committee (HTOC), 2006.
  5. Natl. Inst. Stand. Special Publication 1069. Washington: U.S. Government Printing Office, 2007.
  6. Larin I.K. // Russ. J. Phys. Chem. B 2022. V. 16. № 3. P. 492. https://doi.org/10.1134/S1990793122030083
  7. Linteris G.T., Fumiaki T., Katta V.R. // Combust. Flame. 2007. V. 149. № 1–2. P. 91. https://doi.org/10.1016/j.combustflame.2006.12.013
  8. Halocarbons: Ozone Depletion and Global Warming Overview. Washington: NASA. 2006.
  9. Lightfoot P.D., Cox R.A., Crowley J.N. et al. // Atmos. Environ. Part A. 1992. V. 26. № 10. P. 1805. https://doi.org/10.1016/0960-1686(92)90423-I
  10. Biggs P., Canosa-Mas C.E., Fracheboud J.-M. et al. // Geophys. Res. Lett. 1995. V. 22. № 10. P. 1221. https://doi.org/10.1029/95GL01011
  11. Nielsen O.J., Sehested J. // Chem. Phys. Lett. 1993. V. 213. P. 433. https://doi.org/10.1016/0009-2614(93)89139-9
  12. Wallington T.J., Hurley M.D., Schneider W.F. // Chem. Phys. Lett. 1993. V. 213. P. 442. https://doi.org/10.1016/0009-2614(93)89140-D
  13. Tyndall G.S., Cox R.A., Granier C. et al. // J. Geophys. Res. 2001. V. 106. № D11. P. 12157. https://doi.org/10.1029/2000JD900746
  14. Wallington T.J., Dagaut P., Kurylo M.J. // Chem. Rev. 1992. V. 92. № 4. P. 667. https://doi.org/10.1021/cr00012a008
  15. Nielsen O.J., Ellermann T., Sehested J. et al // Int. J. Chem. Kinet. 1992. V. 24. № 11. P. 1009. https://doi.org/10.1002/kin.550241111
  16. Nielsen O.J., Ellermann T., Bartkiewicz E. et al. // Chem. Phys. Lett. 1992. V. 192. № 1. P. 82. https://doi.org/10.1016/0009-2614(92)85432-A
  17. Maricq M.M., Szente J.J. // J. Phys. Chem. 1992. V. 96. № 12. P. 4925. https://doi.org/10.1021/j100191a037
  18. Wallington T.J., Ball J.C., Nielsen O.J. et al. // J. Phys. Chem. 1992. V. 96(3). P. 1241. https://doi.org 10.1021/j100182a041
  19. Barker J.R. Progress and Problems in Atmospheric Chemistry. Singapore: World Scientific Publishing Company, 1995. https://doi.org/10.1142/2455
  20. Sehested J.. Atmospheric Chemistry of Hydrofluorocarbons and Hydrochlorocarbons. Roskilde, Denmark: Riso National Laboratory, 1995.
  21. Semenov N.N. Chain reactions. Moscow: Nauka, 1986.
  22. Belyakova T.I., Larin I.K., Messineva N.A. et al. // Russ. J. Phys. Chem. B 2018. V. 12. № 2. P. 352. https://doi.org/10.1134/S1990793118020045
  23. Chemical Kinetics and Photochemical Data for Use in Atmospheric Studies. Evaluation No. 17. JPL Publication 10-6. Pasadena, Jet Propulsion Laboratory, 2011. http://jpldataeval.jpl.nasa.gov
  24. Larin I.K., Belyakova T.I., Messineva N.A. et al. // Kinetics and Catalysis. 2014. V. 55. № 5. P. 549. https://doi.org/10.1134/S0023158414050085
  25. Belyakova T.I., Larin I.K., Messineva N.A. et al. // Kinetics and Catalysis. 2017. V. 58. № 2. P. 105. https://doi.org/10.7868/S0453881117020010
  26. Ugarov A.A. Candidate’s thesis for the degree of Candidate of physical and mathematical Sciences. Moscow: INEPCP RAS, 2003.

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2. Fig. 1. Dependence of the partial pressure P of molecular bromine on the time t of irradiation of a mixture of CF₃Br (30 Torr) with O₂ (150 Torr). Temperature T = 298 K.

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3. Fig. 2. Dependence of the optical density D on the time t of irradiation of a mixture of CF₃Br (30 Torr) with O₂ (150 Torr) in the absorption region of CF₃Br (λ = 214 nm).

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4. Fig. 3. Dependence of the partial pressure P of molecular bromine on the time t of irradiation of a mixture of CHF₂Br (39 Torr) with O₂ (150 Torr). Temperature T = 298 K.

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5. Fig. 4. Dependence of the optical density D on the time t of irradiation of a mixture of CHF₂Br (39 Torr) with O₂ (150 Torr) in the absorption region of CHF₂Br (λ = 224 nm).

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6. Fig. 5. Dependence of the optical density D on the time t of irradiation of a mixture of CF₂ClBr (10.4 Torr) with O₂ (150 Torr) in the absorption region of CF₂ClBr (λ = 222 nm).

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7. Fig. 6. Dependence of the partial pressure P of bromine chloride on the time t of irradiation of a mixture of CF₂ClBr (10.4 Torr) with O₂ (150 Torr). Temperature T = 298 K.

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