Kinetics and Mechanism of the Reactions of 2,3-Butadione with F and Cl Atoms, UV Absorption Spectra of CH3C(O)C(O)CH2· and CH3C(O)C(O)CH2O2· Radicals, and Atmospheric Fate of CH3C(O)C(O)CH2O· Radicals
| Autor: | A. Guschin, Michael D. Hurley, Timothy J. Wallington, Ole John Nielsen, L. K. Christensen, Jens Sehested |
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| Rok vydání: | 1998 |
| Předmět: | |
| Zdroj: | The Journal of Physical Chemistry A. 102:8913-8923 |
| ISSN: | 1520-5215 1089-5639 |
| DOI: | 10.1021/jp982431y |
| Popis: | FTIR-smog chamber techniques were used to determine rate constants for the gas-phase reaction of Cl and F atoms with CH3C(O)C(O)CH3 and F atoms with CH3C(O)F of (4.0 ± 0.5) × 10-13, (4.9 ± 0.7) × 10-11, and (3.6 ± 0.4) × 10-12 cm3 molecule-1 s-1, respectively. Two pathways for the reaction of Cl and F atoms with CH3C(O)C(O)CH3 were found: (1a) Cl + CH3C(O)C(O)CH3 → HCl + CH3C(O)C(O)CH2·, (1b) Cl + CH3C(O)C(O)CH3 → CH3C(O)Cl + CH3C(O)·, (2a) F + CH3C(O)C(O)CH3 → HF + CH3C(O)C(O)CH2·, (2b) F + CH3C(O)C(O)CH3 → CH3C(O)F + CH3C(O)·, with branching ratios of k1b/(k1b + k1a) = 0.23 ± 0.02 and k2b/(k2b + k2a) = 0.56 ± 0.09. It was determined that the atmospheric fate of CH3C(O)C(O)CH2O· radicals is decomposition to give HCHO, CO, and CH3C(O)· radicals. Pulse radiolysis coupled to UV absorption spectroscopy was used to study the kinetics of the reaction of F atoms with CH3C(O)C(O)CH3 as well as spectra of CH3C(O)C(O)CH2· and CH3C(O)C(O)CH2O2· radicals over the wavelength range 220−400 nm at 295 K. The rate const... |
| Databáze: | OpenAIRE |
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