Kinetics and mechanism of the reaction of CH3 and CH3O with ClO and OClO at 298 K

Abstract

A discharge-flow system equipped with a laser-induced fluorescence cell to detect the methoxyl radical and a quadrupole mass spectrometer to detect both the chlorine monoxide and chlorine dioxide radicals has been used to measure the rate constants for the reactions CH₃+ ClO → products (1), CH₃O + ClO → products (2), CH₃+ OClO → products (3), CH₃+ OClO → products (4), at T= 298 K and P= 1–3 Torr. The observed products of these reactions are CH₃O for reaction (1), HOCl for reaction (2), and CH₃O and ClO for reaction (3). For reaction (4), CH₃OCl is a possible product. The rate constants derived for reactions (1)–(4) are: k₁=(1.3 ± 0.4)× 10^–10 cm³ molecule^–1 s^–1; k₂=(1.3 ± 0.3)× 10^–11 cm³ molecule^–1 s^–1; k₃=(1.6 ± 0.3)× 10^–11 cm³ molecule^–1 s^–1; k₄=(1.5 ± 0.5)× 10^–12 cm³ molecule^–1 s^–1. The likely mechanisms for reactions (1)–(4) are briefly discussed.