ISSN:
0538-8066
Keywords:
Chemistry
;
Physical Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Experiments have been carried out on the oxidation of CF3CFH2 (HFC-134a). Reaction was initiated by continuous photolysis of F2 in the near-ultraviolet. The F atoms produced abstracted a hydrogen atom from CF3CFH2 initiating oxidation in gas mixtures containing O2 and made up to a total pressure of 700 torr with N2. Product yields were measured using Fourier-transform infrared (FTIR) spectroscopy. Experiments were performed with several different partial pressures of O2 present, and at three temperatures; 298, 323, and 357 K. The major products were HC(O)F, CF3C(O)F, and CF3O3CF3, consistent with H atom abstraction by O2 and CC bond scission being the dominant loss processes for CF3CFHO radicals:\documentclass{article}\pagestyle{empty}\begin{document}$ CF3CFHO+O2 \rightarrow CF3C(O)F+HO2 (4a) $\end{document}\documentclass{article}\pagestyle{empty}\begin{document}$ CF3CFHO+M \rightarrow CF3+HC(O)F+M (4b) $\end{document}The following expression was derived for the ratio of rate constants for these reactions:k4a/k4b=(3.8±1.6)×10-24 exp[(2400±500)/T]cm3 molecule-1 (viii)The main fate of the CF3 radicals was formation of CF3O3CF3 and small amounts of CF3OH were detected. The results of the present experiments in which F atoms were used to initiate reaction are in good agreement with those of previous studies in which Cl atoms were employed to initiate the oxidation of HFC-134a. © 1998 John Wiley & Sons, Inc. Int J Chem Kinet 30: 541-554, 1998
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
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