Atmospheric Chemistry and Physics www.atmos-chem-phys.net 1680-7316 1680-7324 1 1 2001 10.5194/acp-1-1-2001 http://www.atmos-chem-phys.net/1/1/2001/ http://www.atmos-chem-phys.net/1/1/2001/acp-1-1-2001.html http://www.atmos-chem-phys.net/1/1/2001/acp-1-1-2001.pdf 1 7 2001-11-22 298 K rate coefficients for the reaction of OH with <i>i</i> - C₃H₇I, <i>n</i> - C₃H₇I and C₃H₈ S. A. Carl J. N. Crowley Department of Chemistry, University of Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium Max-Planck-Institut für Chemie, Division of Atmospheric Chemistry, Postfach 3060, D-55020 Mainz, Germany The kinetics of the title reactions were investigated using the laser photolysis - resonance fluorescence method, employing the sequential two-photon dissociation of NO₂ in the presence of H₂&nbsp; as the OH source. The 298 K rate constant for OH + C₃H₈ was found to be (1.15 ± 0.1) × 10^-12 cm³ s^-1, in excellent agreement with the literature recommendation, and with a separate determination using HNO₃&nbsp; photolysis at 248 nm as the OH source. The 298 K rate constants for OH + <i>n </i>- C₃H₇I and&nbsp; <i>i </i>- C₃H₇I&nbsp; were measured for the first time and found to be (1.47 ± 0.08) and (1.22 ± 0.06) × 10^-12 cm³ s^-1, respectively. The errors include an assessment of systematic error due to concentration measurement, which, for the propyl-iodides was minimised by on-line UV-absorption spectroscopy. These results show that reaction with OH is an important sink for&nbsp; <i>n </i>- C₃H₇I and&nbsp; <i>i </i>- C₃H₇I, which has implications for the reactive iodine budget of the marine boundary layer.