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 00:00:00 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), Vol. 92:13
• Country of Publication: United States
• Language: English

Related Subjects

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