Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 5.509 IF 5.509
  • IF 5-year value: 5.689 IF 5-year 5.689
  • CiteScore value: 5.44 CiteScore 5.44
  • SNIP value: 1.519 SNIP 1.519
  • SJR value: 3.032 SJR 3.032
  • IPP value: 5.37 IPP 5.37
  • h5-index value: 86 h5-index 86
  • Scimago H index value: 161 Scimago H index 161
Discussion papers
https://doi.org/10.5194/acp-2018-848
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/acp-2018-848
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

Research article 18 Sep 2018

Research article | 18 Sep 2018

Review status
This discussion paper is a preprint. A revision of the manuscript was accepted for the journal Atmospheric Chemistry and Physics (ACP).

Estimating the saturation vapor pressures of isoprene oxidation products C5H12O6 and C5H10O6 using COSMO-RS

Theo Kurtén1, Noora Hyttinen1, Emma L. D'Ambro2,3, Joel Thornton2,3, and Nønne L. Prisle4 Theo Kurtén et al.
  • 1University of Helsinki, Department of Chemistry and Institute for Atmospheric and Earth System Research (INAR), Helsinki, FI-00014, Finland
  • 2Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
  • 3Department of Atmospheric Sciences, University of Washington, Seattle, Washington 98195, United States
  • 4University of Oulu, Nano and Molecular Systems Research Unit, P.O. Box 3000, 90014, University of Oulu, Oulu, Finland

Abstract. We have used COSMO-RS (the COnductor-like Screening MOdel for Real Solvents), as implemented in the COSMOTherm program, to compute the saturation vapor pressures at 298K of two photo-oxidation products of isoprene: the dihydroxy dihydroperoxide C5H12O6, and the dihydroperoxy hydroxy aldehyde, C5H10O6. The predicted saturation vapor pressures were significantly higher (by up to a factor of 1000) than recent experimental results, very likely due to the overestimation of the effects of intramolecular hydrogen bonds, which tend to increase saturation vapor pressures by stabilizing molecules in the gas phase relative to the liquid. Modifying the hydrogen bond enthalpy parameter used by COSMOTherm can improve the agreement with experimental results – however the optimal parameter value is likely to be system-specific. Alternatively, vapor pressure predictions can be substantially improved (to within a factor of 10 of the experimental values for the two systems studied here) by selecting only conformers with a minimum number of intramolecular hydrogen bonds. The computed saturation vapor pressures were very sensitive to the details of the conformational sampling approach, with the default scheme implemented in the COSMOconf program proving insufficient for the task, for example by predicting significant differences between enantiomers, which should have identical physical properties. Even after exhaustive conformational sampling, COSMOTherm predicts significant differences in saturation vapor pressures between both structural isomers and diastereomers. For C5H12O6, predicted differences in psat between structural isomers are up to two orders of magnitude, and differences between stereoisomers up to a factor of 20 – though these differences are very likely exaggerated by the overestimation of the effect of intramolecular H-bonds. For C5H10O6, predicted differences between (stereo)isomers are below a factor of 3. In future studies of saturation vapor pressures of polyfunctional atmospheric oxidation products using COSMOTherm, we recommend first performing thorough conformational sampling, and subsequently selecting conformers with a minimal number of intramolecular H-bonds.

Theo Kurtén et al.
Interactive discussion
Status: final response (author comments only)
Status: final response (author comments only)
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
[Login for Authors/Co-Editors] [Subscribe to comment alert] Printer-friendly Version - Printer-friendly version Supplement - Supplement
Theo Kurtén et al.
Data sets

Supplementary data for the manuscript "Estimating the saturation vapor pressures of isoprene oxidation products C5H12O6 and C5H10O6 using COSMO-RS", submitted to Atmospheric Chemistry and Physics (Discussions) T. Kurtén, N. Hyttinen, E. L. D'Ambro, J. Thornton, and N. Prisle https://doi.org/10.5281/zenodo.1344890

Theo Kurtén et al.
Viewed  
Total article views: 346 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
274 67 5 346 15 3 4
  • HTML: 274
  • PDF: 67
  • XML: 5
  • Total: 346
  • Supplement: 15
  • BibTeX: 3
  • EndNote: 4
Views and downloads (calculated since 18 Sep 2018)
Cumulative views and downloads (calculated since 18 Sep 2018)
Viewed (geographical distribution)  
Total article views: 346 (including HTML, PDF, and XML) Thereof 345 with geography defined and 1 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Cited  
Saved  
No saved metrics found.
Discussed  
No discussed metrics found.
Latest update: 20 Nov 2018
Publications Copernicus
Download
Short summary
We use COSMO-RS to compute saturation vapour pressures for two products of isoprene photo-oxidation, and compare the results to measurements. COSMO-RS is an attractive option for calculating properties of molecules, as it is based on quantum mechanics, and requires few fitting parameters. However, we show that the default implementation of this method suffers from errors related to both conformational sampling, and intramolecular hydrogen bonding. We propose solutions to these problems.
We use COSMO-RS to compute saturation vapour pressures for two products of isoprene...
Citation
Share