UV absorption spectra of HO2, CH3O2, C2H5O2, and CH3C(O)CH2O2 radicals and mechanism of the reactions of F and Cl atoms with CH3C(O)CH3

✍ Scribed by Ole J. Nielsen; Matthew S. Johnson; Timothy J. Wallington; Lene K. Christensen; Jesper Platz

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 314 KB
• Volume: 34
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.10037

✦ Synopsis

Abstract

Pulse radiolysis techniques were used to measure the gas phase UV absorption spectra of the title peroxy radicals over the range 215–340 nm. By scaling to σ(CH~3~O~2~)~240 nm~ = (4.24 ± 0.27) × 10^−18^, the following absorption cross sections were determined: σ(HO~2~)~240 nm~ = 1.29 ± 0.16, σ(C~2~H~5~O~2~)~240 nm~ = 4.71 ± 0.45, σ(CH~3~C(O)CH~2~O~2~)~240 nm~ = 2.03 ± 0.22, σ(CH~3~C(O)CH~2~O~2~)~230 nm~ = 2.94 ± 0.29, and σ(CH~3~C(O)CH~2~O~2~)~310 nm~ = 1.31 ± 0.15 (base e, units of 10^−18^ cm^2^ molecule^−1^). To support the UV measurements, FTIR‐smog chamber techniques were employed to investigate the reaction of F and Cl atoms with acetone. The F atom reaction proceeds via two channels: the major channel (92% ± 3%) gives CH~3~C(O)CH~2~ radicals and HF, while the minor channel (8% ± 1%) gives CH~3~ radicals and CH~3~C(O)F. The majority (>97%) of the Cl atom reaction proceeds via H atom abstraction to give CH~3~C(O)CH~2~ radicals. The results are discussed with respect to the literature data concerning the UV absorption spectra of CH~3~C(O)CH~2~O~2~ and other peroxy radicals. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 34: 283–291, 2002