The reactions of IO with HO2, NO and CH3SCH3: Flow tube studies of kinetics and product formation

Abstract

Rate coefficients for the reaction between IO and HO2 and between IO and NO were obtained using a low-pressure flow tube at total pressures of 1.0–2.0 Torr of He, and between 353 and 273 K. Reactants and products were detected using a quadrupole mass spectrometer. The temperature-dependent rate coefficient for the reaction between IO and HO2 is described by k2 = (2.2 ± 0.6) × 10−11 exp{(400 ± 80)/T} cm3 s−1. The temperature-dependent rate coefficient for the reaction between IO and NO is described by k4 = (8.3 ± 2.3) × 10−12 exp{(269 ± 85)/T} cm3 s−1. The rate coefficient at 298 K (and 2.5–2.7 Torr He) for the reaction of IO and CH3SCH3 was found to be k5 = (1.6 ± 0.3) × 10−14 cm3 s−1. At all the temperatures used in this study the only products observed were HOI from reaction (2), NO2 from reaction (4), and CH3S(O)CH3 from reaction (5).