Thumbnail
Access Restriction
Open

Author Kumaran, S. S. ♦ Su, M. C. ♦ Lim, K. P. ♦ Michael, J. V. ♦ Wagner, A. F.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword CHEMISTRY ♦ ENVIRONMENTAL SCIENCES ♦ ORGANIC CHLORINE COMPOUNDS ♦ DECOMPOSITION ♦ ABSORPTION SPECTRA ♦ CHEMICAL REACTION KINETICS ♦ ORGANIC FLUORINE COMPOUNDS ♦ EXPERIMENTAL DATA ♦ MATHEMATICAL MODELS ♦ CALCULATION METHODS ♦ DISSOCIATION ♦ TEMPERATURE DEPENDENCE ♦ THERMOCHEMICAL PROCESSES
Abstract 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.
ISSN 00223654
Educational Use Research
Learning Resource Type Article
Publisher Date 1996-05-02
Publisher Department Argonne National Laboratory (ANL), Argonne, IL
Publisher Place United States
Journal Journal of Physical Chemistry
Volume Number 100
Issue Number 18
Organization Argonne National Laboratory (ANL), Argonne, IL


Open content in new tab

   Open content in new tab