A kinetics and mechanistic study of the atmospherically relevant reaction between molecular chlorine and dimethyl sulfide (DMS)

Abstract

A gas-phase kinetics study of the atmospherically important reaction between Cl₂ and dimethyl sulfide (DMS)Cl₂ + CH₃SCH₃ → productshas been made using a flow-tube interfaced to a photoelectron spectrometer. The rate constant for this reaction has been measured at 1.6 and 3.0 torr at T = (294 ± 2) K as (3.4 ± 0.7) × 10⁻¹⁴ cm³ molecule⁻¹ s⁻¹. Reaction (1) has been found to proceed via an intermediate, (CH₃)₂SCl₂, to give CH₃SCH₂Cl and HCl as the products. The mechanism of this reaction and the structure of the intermediate were investigated using electronic structure calculations. A comparison of the mechanisms of the reactions between Cl atoms and DMS, and Cl₂ and DMS has been made and the relevance of the results to atmospheric chemistry is discussed.