Reaction of O(3P) with the alkyl iodides: CF3I, CH3I, CH2I2, C2H5I, 1-C3H7I and 2-C3H7I

Abstract

The kinetics of the reactions between O(³P) and various alkyl iodides (RI) was investigated using the pulsed laser photolysis–resonance fluorescence (PLP–RF) technique at temperatures between 223 and 363 K. The reactions studied were O(³P) + CF₃I (1), O(³P) + CH₃I (2), O(³P) + CH₂I₂ (3), O(³P) + C₂H₅I (4), O(³P) + 1-C₃H₇I (5), and O(³P) + 2-C₃H₇I (6). The Arrhenius expressions (units of cm³ molecule⁻¹ s⁻¹) obtained were: k₁(223–363 K) = (8.73 ± 1.29) × 10⁻¹²exp{−(216 ± 38)/T}, k₂(223–363 K) = (9.88 ± 1.67) × 10⁻¹²exp{(183 ± 50)/T}, k₃ (256–363 K) = (7.36 ± 0.31) × 10⁻¹¹ cm³ molecule⁻¹ s⁻¹, k₄(223–363 K) = (1.58 ± 0.22) × 10⁻¹¹exp{(239 ± 39)/T} k₅(223–363 K) = (1.10 ± 0.17) × 10⁻¹¹exp{(367 ± 42)/T}, and k₆(223–363 K) = (1.84 ± 0.31) × 10⁻¹¹exp{(296 ± 46)/T}. With the exception of k₁ and k₃, all the other rate coefficients display a negative temperature dependence, which highlights the importance of association complex formation in reactions of O(³P) + RI.