Atmospheric chemistry of HFC-134a. Kinetic and mechanistic study of the CF[sub 3]CFHO[sub 2] + HO[sub 2] reaction

Journal Article · Thu Sep 08 04:00:00 EDT 1994 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100087a025· OSTI ID:6954349

Maricq, M M; Szente, J J; Hurley, M D; Wallington, T J ^[1]

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1. Ford Motor Company, Dearborn, MI (United States)

Rate constant measurements for the title reaction and for F + CF[sub 3]CFH[sub 2] are reported over the 210-363 K temperature range. Reacting mixtures of CF[sub 3]CFHO[sub 2] and HO[sub 2] radicals are created by the flash photolysis of F[sub 2] in the presence of HFC-134a (CF[sub 3]CFH[sub 2]), H[sub 2], and O[sub 2] and are probed by time-resolved UV absorption spectroscopy. The deconvolution of spectra taken at various delay times provides concentration versus time profiles for the respective radical species. A comparison of the initial CF[sub 3]CFHO[sub 2] and HO[sub 2] concentrations yields a relative rate determination of k[sub 1] = (9.8[sub [minus]5][sup +9]) x 10[sup [minus]11]e[sup (1130[+-]190)/T] cm[sup 3] s[sup [minus]1] for the F + CF[sub 3]CFH[sub 2] rate constant. A simultaneous fit of the radical decay curves to a mechanism containing the known HO[sub 2] self-reaction kinetics, the previously determined CF[sub 3]CFHO[sub 2] self-reaction mechanism, and a cross reaction between these species yields a rate constant of k[sub 7] = (1.8[sub [minus]1.0][sup +2.4]) x 10[sup [minus]13]e[sup (910[+-]220)/T] cm[sup 3] s[sup [minus]1] for the HO[sub 2] + CF[sub 3]CFHO[sub 2] reaction. A product study at 296 K by Fourier transform infrared spectroscopy reveals that less than 5% of the product appears as CF[sub 3]C(O)F. By inference >95% of the reaction gives the hydroperoxide CF[sub 3]CFHOOH. 34 refs., 7 figs., 4 tabs.

• OSTI ID: 6954349
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 98:36; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102 -- Chemical & Spectral Procedures
400201 -- Chemical & Physicochemical Properties
400500* -- Photochemistry
54 ENVIRONMENTAL SCIENCES
540110
540120 -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (1990-)
ATMOSPHERIC CHEMISTRY
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISTRY
COMPILED DATA
DATA
DECOMPOSITION
ELEMENTS
FLUORINATED ALIPHATIC HYDROCARBONS
FLUORINE
HALOGENATED ALIPHATIC HYDROCARBONS
HALOGENS
HYDROGEN
HYDROPEROXY RADICALS
INFORMATION
INFRARED SPECTRA
KINETICS
NITRIC OXIDE
NITROGEN COMPOUNDS
NITROGEN OXIDES
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
OZONE
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
RADICALS
REACTION KINETICS
SPECTRA
ULTRAVIOLET SPECTRA