Absorption spectrum and kinetics of reactions of the acetylperoxy radical

Journal Article · Thu Mar 23 04:00:00 EST 1989 · Journal of Physical Chemistry; (USA)

DOI:https://doi.org/10.1021/j100343a032· OSTI ID:5111177

Moortgat, G; Veyret, B; Lesclaux, R ^[1]

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1. Universite de Bordeaux l, Talence (France)

The ultraviolet absorption spectrum of the acetylperoxy radical was measured in the range 190-280 nm. The radical was generated by flash photolysis of Cl{sub 2}/CH{sub 3}CHO/O{sub 2} mixtures. The absorption spectrum was calibrated against the HO{sub 2} radical generated in the Cl{sub 2}/CH{sub 3}OH/O{sub 2} system. The spectrum shows a strong maximum at 207 nm, with {sigma} = 9.5 {times} 10{sup {minus}18} cm{sup 2} molecule{sup {minus}1} and a weak maximum near 245 nm with {sigma} = 3.7 {times} 10{sup {minus}18} cm{sup 2} molecule{sup {minus}1}. Kinetic data were obtained at 600 Torr of air over the temperature range 253-368 K. Rate constants were deduced from computer simulations of the absorption traces obtained at various wavelengths using nonlinear least-squares treatment of multiple time profiles. The following reactions were studied: 2CH{sub 3}COO{sub 2} {yields} 2CH{sub 3}COO + O{sub 2} (4); CH{sub 3}COO{sub 2} + CH{sub 3}O{sub 2} {yields} CH{sub 3}COO + CH{sub 3}O + O{sub 2} (3a); CH{sub 3}COO{sub 2} + CH{sub 3}O{sub 2} {yields} CH{sub 3}COOH + HCHO + O{sub 2} (3b); the rate constants can be expressed in Arrhenius form as follows: k{sub 4} = 2.8 {times} 10{sup {minus}12} exp((530 {plus minus} 100)/T); k{sub 3a} = 1.8 {times} 10{sup {minus}9} exp(-(1800 {plus minus} 1100)/T); k{sub 3b} = 4.1 {times} 10{sup {minus}15} exp((2100 {plus minus} 1200)/T), all in units of cm{sup 3} molecule{sup {minus}1} s{sup {minus}1}, the errors being 2 standard deviations. These expressions are valid only at tropospheric temperatures, and a global value of k{sub 3}, independent of the temperature, is k{sub 3} = (1.4 {plus minus} 0.3) {times} 10{sup {minus}11} cm{sup 3} molecule{sup {minus}1} s{sup {minus}1}.

• OSTI ID: 5111177
• Journal Information: Journal of Physical Chemistry; (USA), Journal Name: Journal of Physical Chemistry; (USA) Vol. 93:6; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500* -- Photochemistry
ABSORPTION SPECTROSCOPY
ACETALDEHYDE
ACETYL RADICALS
ACYL RADICALS
ALDEHYDES
ARRHENIUS EQUATION
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHEMISTRY
CHLORINE COMPOUNDS
DATA
DECOMPOSITION
EQUATIONS
EXPERIMENTAL DATA
HALOGEN COMPOUNDS
INFORMATION
KINETICS
NUMERICAL DATA
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PEROXY RADICALS
PHOTOCHEMICAL REACTIONS
PHOTOCHEMISTRY
PHOTOLYSIS
PHYSICAL PROPERTIES
RADICALS
REACTION KINETICS
SPECTRA
SPECTROSCOPY
THERMODYNAMIC PROPERTIES
ULTRAVIOLET SPECTRA