Atmospheric Chemistry of Cyclohexanone: UV Spectrum and Kinetics of Reaction with Chlorine Atoms

Absolute and relative rate techniques were used to study the reactivity of Cl atoms with cyclohexanone in 6 Torr of argon or 800–950 Torr of N2 at 295 ± 2 K. The absolute rate experiments gave k(Cl + cyclohexanone) = (1.88 ± 0.38) × 10−10, whereas the relative rate experiments gave k(Cl + cyclohexanone) = (1.66 ± 0.26) × 10−10 cm3 molecule−1 s−1. Cyclohexanone has a broad UV absorption band with a maximum cross section of (4.0 ± 0.3) × 10−20 cm2 molecule−1 near 285 nm. The results are discussed with respect to the literature data. C © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 223–229, 2008 Correspondence to: T. J. Wallington; e-mail: twalling@ ford.com. Contract grant sponsor: The Ministry of Education, Culture, Sports, Science, and Technology, Japan. Contract grant sponsor: Program for Improvement of Research Environment for Young Researchers from Special Coordination Funds for Promoting Science and Technology (SCF) commissioned by the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan. c © 2008 Wiley Periodicals, Inc. INTRODUCTION Ketones are an important class of oxygenated volatile organic compounds used as solvents and formed during the atmospheric oxidation of most organic compounds [1,2]. Accurate UV spectra and kinetic data for reactions of chlorine atoms with organic compounds are needed in atmospheric chemistry studies for two reasons. First, they are inputs into global atmospheric models to assess the loss of organics via photolysis and