Fate of 1,3-dioxolane in the troposphere: kinetics, mechanism with theoretical support, and atmospheric implications

Abstract

The atmospheric fate of 1,3-dioxolane is assessed by measuring the OH and Cl initiated gas-phase oxidation kinetics, and exploring their mechanistic pathways. Absolute OH reaction rate coefficient of 1,3-dioxolane using laser photolysis-laser induced fluorescence technique is found to be (1.27 ± 0.03) × 10^–11 cm³ molecule⁻¹ s⁻¹ at 298 ± 2 K and it is in good agreement with the measured relative value of (1.13 ± 0.12) × 10^–11 cm³ molecule⁻¹ s⁻¹, using gas-chromatography. Relative value of Cl reaction rate coefficient with 1,3-dioxolane is found to be (1.64 ± 0.60) × 10^–10 cm³ molecule⁻¹ s⁻¹. The tropospheric lifetime of 1,3-dioxolane is calculated to be about 22 h under ambient conditions. Interestingly, it reduces to about 8 h near marine boundary layer, where Cl reaction takes over the OH reaction. Such a short lifetime with respect to reaction with OH and Cl suggests the atmospheric impact of 1,3-dioxolane to be local. Formic acid, ethylene carbonate, and 1,2-ethanediol monoformate are observed as stable products in OH as well as Cl oxidation. 1,3-dioxolane may contribute as one of the sources of formic acid in the atmosphere. Theoretical calculations for the OH-initiated hydrogen abstraction of 1,3-dioxolane revealed that the reaction follows an indirect path through the formation of pre- and post-reaction complexes at entrance and exit channels, respectively with the lowest barrier height of 3.5 kcal/mol. Photochemical ozone creation potential of 1,3-dioxolane is calculated.