Thermodynamic properties and cloud droplet activation of a series of oxo-acids 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
Received: 20 Jan 2010 – Published in Atmos. Chem. Phys. Discuss.: 10 Feb 2010Abstract. 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 decarboxylate
in aqueous solution. We studied the effects of this process on our
measurements and findings.
Revised: 08 Jun 2010 – Accepted: 15 Jun 2010 – Published: 02 Jul 2010
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., 10, 5873-5890, doi:10.5194/acp-10-5873-2010, 2010.