298 K rate coefficients for the reaction of OH with <i>i</i> - C<sub>3</sub>H<sub>7</sub>I, <i>n</i> - C<sub>3</sub>H<sub>7</sub>I and C<sub>3</sub>H<sub>8</sub>

Abstract

Abstract. The kinetics of the title reactions were investigated using the laser photolysis -resonance fluorescence method, employing the sequential two-photon dissociation of NO 2 in the presence of H 2 as the OH source. The 298 K rate constant for OH + C 3 H 8 was found to be (1.15 ± 0.1) × 10 −12 cm 3 s −1 , in excellent agreement with the literature recommendation, and with a separate determination using HNO 3 photolysis at 248 nm as the OH source. The 298 K rate constants for OH + n−C 3 H 7 I and i−C 3 H 7 I were measured for the first time and found to be (1.47 ± 0.08) and (1.22 ± 0.06) × 10 −12 cm 3 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 n−C 3 H 7 I and i−C 3 H 7 I, which has implications for the reactive iodine budget of the marine boundary layer.

Evaluated kinetic and photochemical data for atmospheric chemistry: Volume II – gas phase reactions of organic species

“…The preferred Arrhenius expression predicts a rate coefficient at 190 K which is within 4% of that measured by . The relative rate coefficients of , , , , and are in good agreement with the recommended expression, as are the absolute rate coefficients of (judged to be superseded by the study of , , and Carl and Crowley (2001).…”

Determination of Atmospheric Lifetimes via the Measurement of OH Radical Kinetics

“…410−450 nm) using a dye laser pumped by the third harmonic of a Nd:YAG laser: The use of different sources of OH allows one to examine any effects of the hydroxyl source on the derived OH rate constant. These different OH generation methods also allow the use of longer wavelength radiation, which generally results in less photolysis of the reactants, , although such use can complicate chemistry in the reacting mixture because of the reaction between OH and its precursors. Thus, extreme care must be taken to ensure that the measured OH rate constants are not affected by complications due to reactant photolysis or OH reactions with its precursors.…”