Atmos. Chem. Phys. Discuss., 10, 3755-3805, 2010
© Author(s) 2010. This work is distributed
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This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
Thermodynamic properties and cloud droplet activation of a series of oxo-acids
M. Frosch1, A. A. Zardini1, S. M. Platt1, L. Müller2, M.-C. Reinnig2, T. Hoffmann2, and M. Bilde1
1Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
2Department of Inorganic Chemistry and Analytical Chemistry, Johannes Gutenberg-Universität Mainz, Duesbergweg 10–14, 55128 Mainz, Germany

Abstract. We have investigated the thermodynamic properties of four aliphatic oxo-dicarboyxlic acids identified or thought to be present in atmospheric particulate matter: oxosuccinic acid, 2-oxoglutaric acid, 3-oxoglutaric acid, and 4-oxopimelic acid. The compounds were characterized in terms of their cloud condensation nuclei (CCN) activity, vapor pressure, density, and tendency to decarboxylate in aqueous solution. We deployed a variety of experimental techniques and instruments: a CCN counter, a Tandem Differential Mobililty Analyzer (TDMA) coupled with a laminar flow-tube, and liquid chromatography/mass spectrometry (LC/MS). The presence of the oxo functional group in the α-position causes the vapor pressure of the compounds to diminish by an order of magnitude with respect to the parent dicarboxylic acid, while the CCN activity is similar or increased. Dicarboxylic acids with an oxo-group in the β-position were found to decarboxylate in aqueous solution.

Citation: Frosch, M., Zardini, A. A., Platt, S. M., Müller, L., Reinnig, M.-C., Hoffmann, T., and Bilde, M.: Thermodynamic properties and cloud droplet activation of a series of oxo-acids, Atmos. Chem. Phys. Discuss., 10, 3755-3805, doi:10.5194/acpd-10-3755-2010, 2010.
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