Flash photolysis kinetic absorption spectroscopy study of the gas-phase reaction HO/sub 2/ + C/sub 2/H/sub 5/O/sub 2/ over the temperature range 228-380 K

Journal Article · Thu Jun 30 04:00:00 EDT 1988 · J. Phys. Chem.; (United States)

DOI:https://doi.org/10.1021/j100324a031· OSTI ID:6477658

Dagaut, P; Wallington, T J; Kurylo, M J

Flash photolysis kinetic absorption spectroscopy was used to investigate the gas-phase reaction between hydroperoxy and ethylperoxy radicals between 228 and 380 K in the pressure range 25-400 Torr: HO/sub 2/ + C/sub 2/H/sub 5/O/sub 2/ ..-->.. products (1). Due to the large difference between the self-reactivities of the two radicals, first- or second-order kinetic conditions could not be maintained for either species. Thus, the rate constant for reaction 1 was determined from computer-modeled fits of the radical absorption decay curves recorded at wavelengths between 230 and 280 nm. This procedure yielded a value for k/sub 1/ at 298 K of (5.3 +/- 1.0) x 10/sup -12/ cm/sup 3/ molecule/sup -1/ s/sup -1/ independent of total pressure (using N/sub 2/) between 25 and 400 Torr. The Arrhenius expression derived from the present study over the temperature range 248-380 K is k/sub 1/ = (5.6 +/- 2.4) x 10/sup -13/ exp((650 +/- 125)/T) cm/sup 3/ molecule/sup -1/ s/sup -1/, where the quoted errors are 2 sigma from linear least-squares analyses. A reanalysis of the authors earlier measurements of the C/sub 2/H/sub 5/O/sub 2/ self-reaction, C/sub 2/H/sub 5/O/sub 2/ + C/sub 2/H/sub 5/O/sub 2/ ..-->.. products (2), using this expression for k/sub 1/ results in the revised Arrhenius equation: k/sub 2/ = (8.5 +/- 1.1) x 10/sup -14/ exp(-(110 +/- 40)/T) cm/sup 3/ molecule/sup -1/ s/sup -1/.

• Research Organization: National Bureau of Standards, Gaithersburg, MD (USA)
• OSTI ID: 6477658
• Journal Information: J. Phys. Chem.; (United States), Journal Name: J. Phys. Chem.; (United States) Vol. 92:13; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500* -- Photochemistry
ABSORPTION SPECTROSCOPY
ARRHENIUS EQUATION
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
DECOMPOSITION
EQUATIONS
HYDROPEROXY RADICALS
KINETICS
MEDIUM TEMPERATURE
PEROXY RADICALS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
RADICALS
REACTION KINETICS
SPECTROSCOPY