University of Oulu

Toivola, M., Prisle, N., Elm, J., Waxman, E., Volkamer, R., Kurtén, T. (2017) Can COSMOTherm Predict a Salting in Effect?. J. Phys. Chem. A, 121 (33), 6288-6295.

Can COSMOTherm predict a salting in effect?

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Author: Toivola, Martta1; Prisle, Nønne L.2; Elm, Jonas3;
Organizations: 1Department of Chemistry, University of Helsinki, P.O. Box 55, FI-00014 Helsinki, Finland
2Nano and Molecular Systems Research Unit, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland
3Department of Physics, University of Helsinki, P.O. Box 64, FI-00014 Helsinki, Finland
4Department of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States
5Present address: Applied Physics Division, NIST, Boulder, CO, USA
6CIRES, University of Colorado Boulder, Boulder, Colorado 80309, United States
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 3.9 MB)
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Language: English
Published: American Chemical Society, 2017
Publish Date: 2019-10-30


We have used COSMO-RS, a method combining quantum chemistry with statistical thermodynamics, to compute Setschenow constants (KS) for a large array of organic solutes and salts. These comprise both atmospherically relevant solute-salt combinations, as well as systems for which experimental data are available. In agreement with previous studies on single salts, the Setschenow constants predicted by COSMO-RS (as implemented in the COSMOTherm program) are generally too large compared to experiments. COSMOTherm overpredicts salting out (positive KS), and/or underpredicts salting in (negative KS). For ammonium and sodium salts, KS values are larger for oxalates and sulfates, and smaller for chlorides and bromides. For chloride and bromide salts, KS values usually increase with decreasing size of the cation, along the series Pr4N+ < Et4N+ < Me4N+ ≤ Na+ ≈ NH4+. Of the atmospherically relevant systems studied, salting in is predicted only for oxalic acid in sodium and ammonium oxalate, and sodium sulfate, solutions. COSMOTherm was thus unable to replicate the experimentally observed salting in of glyoxal in sulfate solutions, likely due to the overestimation of salting out effects. By contrast, COSMOTherm does qualitatively predict the experimentally observed salting in of multiple organic solutes in solutions of alkylaminium salts.

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Series: The journal of physical chemistry. A
ISSN: 1089-5639
ISSN-E: 1520-5215
ISSN-L: 1089-5639
Volume: 121
Issue: 33
Pages: 6288 - 6295
DOI: 10.1021/acs.jpca.7b04847
Type of Publication: A1 Journal article – refereed
Field of Science: 116 Chemical sciences
114 Physical sciences
Funding: We thank the Academy of Finland for funding and the CSC IT Center for Science for computer time. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant Agreement No. 717022), and U.S. National Science Foundation (AGS1649147). E.W. is the recipient of an NRC fellowship. J.E. thanks the Carlsberg Foundation for financial support.
EU Grant Number: (717022) SURFACE - The unexplored world of aerosol surfaces and their impacts.
Dataset Reference: The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.jpca.7b04847.
Copyright information: This document is the Accepted Manuscript version of a Published Work that appeared in final form in J. Phys. Chem. A, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see