Thermal decomposition of CFCl{sub 3}
- Argonne National Lab., IL (United States)
The thermal decomposition of CFCl{sub 3} (CFC-11) has been studied in reflected shock waves using the Cl-atom atomic resonance absorption spectroscopy (ARAS) detection technique. The first thermal rate measurements for CFCl{sub 3} (+M) {yields} CFCl{sub 2} + Cl (+M) are reported. The experimental Cl-atom concentration profiles show two distinct rates of formation. The initial fast process gives a Cl-atom yield of 2, and this is followed by slow secondary processes that are density and temperature dependent. The final Cl-atom yield is greater than 2[CFCl{sub 3}]{sub 0}. This behavior confirms that C-Cl bond scission is the dominant dissociation pathway for both CFCl{sub 3} and the product radical, CFCl{sub 2}, as observed in an earlier study from this laboratory on the related CF{sub 2}Cl{sub 2} decomposition. Profile fits require the fast subsequent dissociation of CFCl{sub 2}, and therefore, the short-time kinetics can be best explained as being due to C-Cl bond breaking in the parent, CFCl{sub 3}. The temperature and density dependences of the later time Cl-atom profiles suggest that the slow secondary rate can be ascribed to reactions involving the carbene diradical, CFCl. The Cl-atom data were analyzed with detailed kinetics modeling calculations. Comparison to earlier results from this laboratory on CF{sub 3}Cl, CF{sub 2}Cl, and CCl{sub 4} suggests that the C-Cl bond strength in CFCl{sub 3} should be between those for CF{sub 2}Cl{sub 2} and CCl{sub 4}. 46 refs., 5 figs., 5 tabs.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 249666
- Journal Information:
- Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 18 Vol. 100; ISSN JPCHAX; ISSN 0022-3654
- Country of Publication:
- United States
- Language:
- English
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