Reevaluation of the rate constant for the reaction propene + NO3by absolute rate determination

Atmospheric reactivity of vinyl acetate: kinetic and mechanistic study of its gas-phase oxidation by OH, O3, and NO3

Vinyl acetate is widely used in industry. It has been classified as a high-production volume (HPV) chemical in the United States. To evaluate its impact on the environment and air quality, its atmospheric reactivity toward the three main tropospheric oxidants (OH, NO(3), and O(3)) has been investigated. Kinetic and mechanistic experiments have been conducted at room temperature and atmospheric pressure using an indoor Pyrex simulation chamber coupled to Fourier transform infrared (FTIR) and UV-visible spectrometers. Rate constants for the reactions of vinyl acetate with OH, NO(3), and O(3) were equal to (2.3 +/- 0.3) x 10(-11), (7.3 +/- 1.8) x 10(-15), and (3.0 +/- 0.4) x 10(-18) cm(3) molecule(-1) s(-1), respectively. From these data, tropospheric lifetimes of vinyl acetate have been estimated as follows: tau(OH) = 6 h, tau(NO(3)) = 6 days, and tau(O(3)) = 5 days. This demonstrates that reaction with OH radicals is the main tropospheric loss process of this compound. From the mechanistic experiments, main oxidation products have been identified and quantified and oxidation schemes have been proposed for each studied reaction.