Kinetics, Products and Mechanism of O(3P) Atom Reactions with Alkyl Iodides

Alkyl halides (RX: X = Cl, I) are an important source of halogens in the atmosphere. The major tropospheric sinks of these compounds are photolysis (RBr, RI) and reaction with OH radicals. In the case of alkyl iodides (RI) relative kinetic studies of their OH reactions in photoreactors are complicated by fast reactions with the O(3P) atoms generated by the photochemical OH radical sources. Figure 1 below shows a ln-ln plot of the kinetic data from an experiment performed in a large photoreactor to determine the OH rate coefficient for the reaction OH + CH₃CH₂CH₂I relative to OH + ethene using the photolysis of methyl nitrite (CH₃ONO) as the OH radical source. A recent example of the implementation of the relative kinetic technique for the determination of OH radical rate coefficients in a photoreactor can be found in Olariu et al. (2000).