ATMOCHEM - Reactivity of Oxygenated Volatile Organic Compounds (ROVOC): Esters
Zusammenfassung der Projektergebnisse
Rate coefficients have been obtained for the reactions of OH radicals and, in particular, Cl atoms with a number of saturated acyclic and cyclic alkyl esters and also unsaturated acyclic alkyl esters. Most of the rate coefficients were performed at 298 K but in a few cases the kinetic experiments were performed as a function of temperature. In cooperation with the French project partners more than 50 rate coefficients have been determined for the reactions of OH and Cl with saturated and unsaturated alkyl esters and the work has thus considerably expanded the kinetic data for esters. A substantial raction of the kinetic information has already been posted on the “Chemical Kinetic Database on Oxygenated VOCs” hosted by the French partners at CNRS Orleans (http://www.eraorleans.org/eradb/). Product studies have been performed on the OH radical and Cl atom initiated photooxidation of a selection of the saturated acyclic and cyclic alkyl esters and also the unsaturated acyclic alkyl esters. Many of the product studies have been already published in the peer-reviewed literature. A surprising and unexpected result from the products studies was the very large effect of the presence or absence of NOx in the unsaturated ester photooxidation systems. The large effect on the product distribution for the unsaturated esters has been attributed to the large differences in the chemical activation of the alkoxy radicals produced in the degradation processes with and without NOx. Such a large influence of NOx on the product distributions was not observed for the other types of esters. The combined kinetic and product information for the different types of esters will allow much improved assessments of their impacts on tropospheric photooxidant formation, in particular, ozone and also other potential environmental problems.
Projektbezogene Publikationen (Auswahl)
- OH-Initiated Degradation of unsaturated esters in the atmosphere: Kinetics in the temperature range of 287-313 K. J. Phys. Chem. A 113, (2009) 5958–5965
Blanco, M. B., I. Bejan, I. Barnes, P. Wiesen and M. A. Teruel
- The Cl-initiated oxidation of CH3C(O)OCH=CH2, CH3C(O)OCH2CH=CH2, and CH2=CHC(O)O(CH2)3CH3 in the troposphere. Environ. Sci. Pollut. Res. 16, (2009), 641–648
Blanco, M. B., I. Bejan, I. Barnes, P. Wiesen, and M. A. Teruel
- FTIR product distribution study of Cl and OH initiated degradation of methyl acrylate at atmospheric pressure. Environ. Sci. & Technol. 44, (2010), 7031–7036
Blanco, M. B., I. Bejan, I. Barnes, P. Wiesen and M. A. Teruel
- Product distribution in the Cl-initiated photooxidation of CF3C(O)OCH2CF3. J. Phys. Org. Chem. 23 (2010) 950–954
Blanco, M. B., I. Barnes and M. A. Teruel
- Relative kinetic measurements of rate coefficients for the gas-phase reactions of Cl Atoms and OH radicals with a series of methyl alkyl esters. Atmos. Environ. 44, (2010), 5407-5414
Schütze, N., X. Zhong, S. Kirschbaum, I. Bejan, I. Barnes, and Th. Benter
- Atmospheric Oxidation of Vinyl and Allyl Acetate: Product Distribution and Mechanisms of the OH-Initiated Degradation in the Presence and Absence of NOx. Environ. Sci. Technol. 46 (2012) 8817−8825
Blanco , M. B., I. Bejan, I. Barnes, P. Wiesen and M. A. Terue
(Siehe online unter https://doi.org/10.1021/es3015869)
