Atmospheric Chemistry of Gaseous Diethyl Sulfate

The atmospheric reactivity of diethyl sulfate (DES) has been investigated. Upper limits to the rate constants (in cm³ molecule⁻¹ s⁻¹) for the homogeneous gas-phase reactions of DES with O₃, NH₃, and H₂O have been determined by FTIR spectroscopy and are <3.4 × 10⁻²¹, <1.4 × 10⁻²¹, and ≤2.3 × 10⁻²³, respectively. The reactivity of DES toward OH radicals and Cl atoms has been determined by using relative rate techniques; rate constants for those reactions are (1.8 ± 0.7) × 10⁻¹² and (1.1 ± 0.1) × 10⁻¹¹, respectively. These rate constants correspond to atmospheric lifetimes ranging from ≥1 day with respect to reaction with water to >12 years with respect to ozone. With the possible exception of its reaction with water, these results indicate that the atmospheric fate of DES within an urban air parcel is not determined by its homogeneous gas-phase reactions with any of the atmospheric species studied. No evidence has been found for the formation of DES or related compounds during the ozonolysis of olefins in the presence of SO₂ and ethanol.