Reactions of O(3P) with Alkyl Iodides: Rate Coefficients and Reaction Products

Abstract

The rate coefficients for the reactions of O(3P) with CF3I (1) and CH3I (2) were measured between 213 and 364 K to be: k1(T) = (7.9 ± 0.8) x 10-12 exp[−(175 ± 40)/T] and k2(T) = (1.0 ± 0.2) x 10-11 exp[(160 ± 50)/T] cm3 molecule-1 s-1. The rate coefficients for the reaction of O(3P) with CD3I, (CH3)2CHCH2I, (CH3)2CHI, CF3CH2I, CF3CHFI, and CF3CF2I at 298 K were also measured. The yields of the IO and CF3O products in reaction 1 at 298 K were found to be 0.83 ± 0.09 and <0.01, respectively. Product yields of reaction 2 at 298 K were measured to be IO (0.44 ± 0.04), OH (0.16 ± 0.05), H (0.07 ± 0.02), CH3O (<0.03), and HI (<0.05). IO, OH, and CH3O were detected via laser-induced fluorescence, O and H atoms via resonance fluorescence, and IO, CF3O, and HI by chemical ionization mass spectrometry. The IO yield from reactions 1 and 2 showed a slight positive temperature dependence. Within our experimental error the OH yield from reaction 2 was temperature independent. An upper limit for the enthalpy of formati...