title: Gas-Phase Photolysis of Pyruvic Acid: The Effect of Pressure on Reaction Rates and Products.
abstract: In this work, we investigate the impact of pressure and oxygen on the kinetics of and products from the gas-phase photolysis of pyruvic acid. The results reveal a decrease in the photolysis quantum yield as pressure of air or nitrogen is increased, a trend not yet documented in the literature. A Stern-Volmer analysis demonstrates this effect is due to deactivation of the singlet state of pyruvic acid when the photolysis is performed in nitrogen, and from quenching of both the singlet and triplet state in air. Consistent with previous studies, acetaldehyde and CO2are observed as the major products; however, other products, most notably acetic acid, are also identified in this work. The yield of acetic acid increases with increasing pressure of buffer gas, an effect that is amplified by the presence of oxygen. At least two mechanisms are necessary to explain the acetic acid, including one that requires reaction of photolysis intermediates with O2. These findings extend the fundamental understanding of the gas-phase photochemistry of pyruvic acid, highlighting the importance of pressure on the photolysis quantum yields and products.
authors.affiliation: Department of Chemistry and Biochemistry, CIRES, University of Colorado , Boulder, Colorado 80309, United States.
authors.forename: Allison E
authors.initials: AE
authors.lastname: Reed Harris
authors.affiliation: LISA, UMR-CNRS 7583, Université Paris Est Créteil (UPEC), Université Paris Diderot (UPD), Institut Pierre Simon Laplace (IPSL) , 94010 Créteil, France.
authors.forename: Jean-Francois
authors.initials: JF
authors.lastname: Doussin
authors.affiliation: School of Chemistry, Cardiff University , Cardiff CF10 3AT, U.K.
authors.forename: Barry K
authors.initials: BK
authors.lastname: Carpenter
authors.affiliation: Department of Chemistry and Biochemistry, CIRES, University of Colorado , Boulder, Colorado 80309, United States.
authors.forename: Veronica
authors.identifier: http://orcid.org/0000-0001-5863-8056
authors.initials: V
authors.lastname: Vaida