Kinetic studies of the reaction of Cl atoms with CH3SSCH3

Abstract

The reaction of Cl atoms with dimethyl disulfide, CH₃SSCH₃, was studied in the gas phase and over the temperature range 273–363 K with the very low pressure reactor (VLPR) technique. The reaction proceeds via two competing pathways: (a) hydrogen atom abstraction that produces CH₃SSCH₂ radicals, with a rate given by the expression k_1a=(1.83 ± 0.08)× 10^–10 exp [–(2.43 ± 0.21)/RT] cm³ molecule^–1 s^–1, (R in kJ mol^–1 K^–1, 2σ uncertainty); and (b) an intermediate adduct CH₃S(Cl)SCH₃ formation channel, which further leads to CH₃SCl and CH₃S products, its rate is given by the expression k_1b=(5.17 ± 0.32)× 10^–11 exp [(3.39 ± 0.29)/RT] cm³ molecule^–1 s^–1. The branching ratio k_1a/k_1b was found to be 0.35 at room temperature and low pressure conditions.