ACPD Atmospheric Chemistry and Physics Discussions ACPD 1680-7375 Copernicus GmbH Göttingen, Germany 10.5194/acpd-5-3873-2005 Kinetic isotope effects in the gas phase reactions of OH and Cl with CH<sub>3</sub>Cl, CD<sub>3</sub>Cl, and <sup>13</sup>CH<sub>3</sub>Cl Gola A. A. 1 3 D’Anna B. 1 Feilberg K. L. 2 Sellevåg S. R. 1 Bache-Andreassen L. 1 Nielsen C. J. 1 Department of Chemistry, University of Oslo, P.O.Box 1033 Blindern, N-0315 Oslo, Norway Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark permanent address: Department of Physical Chemistry, Medical University of Wroclaw, Pl. Nankiera, 50-140 Wroclaw, Poland 13 06 2005 5 3 3873 3898 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys-discuss.net/5/3873/2005/acpd-5-3873-2005.html The full text article is available as a PDF file from http://www.atmos-chem-phys-discuss.net/5/3873/2005/acpd-5-3873-2005.pdf

The kinetic isotope effects in the reactions of CH<sub>3</sub>Cl, <sup>13</sup>CH<sub>3</sub>Cl and CD<sub>3</sub>Cl with OH radicals and Cl atoms were studied in relative rate experiments at 298&plusmn;2K and 1013&plusmn;10mbar. The reactions were carried out in a smog chamber using long path FTIR detection and the spectroscopic data analyzed employing a non-linear least squares spectral fitting method using measured high-resolution infrared spectra as well as absorption cross sections from the HITRAN database. The reaction rates of <sup>13</sup>CH<sub>3</sub>Cl and CD<sub>3</sub>Cl with OH and Cl were determined relative to CH<sub>3</sub>Cl as: <i>k</i><sub>OH + CH<sub>3</sub>Cl</sub>/<i>k</i><sub>OH + <sup>13</sup>CH<sub>3</sub>Cl</sub>=1.059&plusmn;0.008, <i>k</i><sub>OH + CH<sub>3</sub>Cl</sub>/<i>k</i><sub>OH + CD<sub>3</sub>Cl</sub>=3.9&plusmn;0.4, <i>k</i><sub>Cl + CH<sub>3</sub>Cl</sub>/<i>k</i><sub>Cl + <sup>13</sup>CH<sub>3</sub>Cl</sub>=1.070&plusmn;0.010 and <i>k</i><sub>Cl + CH<sub>3</sub>Cl</sub>/<i>k</i><sub>Cl + CD<sub>3</sub>Cl</sub>=4.91&plusmn;0.07. The uncertainties given are 2&sigma; from the statistical analyses and do not include possible systematic errors. The unusually large <sup>13</sup>C kinetic isotope effect in the OH reaction of CH<sub>3</sub>Cl has important implications for the global emission inventory of CH<sub>3</sub>Cl.