A study of the reactions of NO₃ radicals with organic sulfides: Reactivity trend at 298 K

A laser flash photolysis‐long path laser absorption technique has been employed to investigate the kinetics of NO 3 reactions with CH 3 SCH 3 (𝓀 1 ), CD 3 SCD 3 (𝓀 2 ), and C 2 H 5 SC 2 H 5 (𝓀 3 ) in 500 torr air at 298 K. The dependence of 𝓀 1 on total pressure (20–500 torr) and oxygen partial pressure (0—100 torr) has also been investigated, with no dependence observed. Measured rate coefficients in units of 10 −13 cm 3 molecule −1 s −1 are 𝓀 1 = 13 ± 3, 𝓀 2 = 3.4 ± 0.8, and 𝓀 3 = 48 ± 12, where the quoted uncertainties are 2σ estimates of absolute accuracy. The magnitude of NO 3 + sulfide rate coefficients and negative activation energies for 𝓀 1 (reported by other investigators) suggest that reaction does not proceed via a direct hydrogen abstraction mechanism. However, the reactivity trend observed in this study provides evidence that the reaction mechanism does involve breaking a carbon‐hydrogen bond.