Calculation of the Vapour Pressure of Organic Molecules by Means of a Group-Additivity Method and Their Resultant Gibbs Free Energy and Entropy of Vaporization at 298.15 K

The calculation of the vapour pressure of organic molecules at 298.15 K is presented using a commonly applicable computer algorithm based on the group-additivity method. The basic principle of this method rests on the complete breakdown of the molecules into their constituting atoms, further charact...

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Bibliographic Details
Published in:Molecules (Basel, Switzerland) Switzerland), 2021-02, Vol.26 (4), p.1045
Main Authors: Naef, Rudolf, Acree, Jr, William E
Format: Article
Language:English
Subjects:
Algorithms
Correlation coefficient
Correlation coefficients
Entropy
entropy of vaporization
Experimental data
Free energy
Gibbs free energy
Gibbs free energy of vaporization
group-additivity method
Heat
Hydrocarbons
Neural networks
Organic Chemicals - chemistry
Organic chemistry
Pressure
Research methodology
Standard error
Thermodynamics
Vapor Pressure
Vaporization
vapour pressure
Volatilization
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Summary:The calculation of the vapour pressure of organic molecules at 298.15 K is presented using a commonly applicable computer algorithm based on the group-additivity method. The basic principle of this method rests on the complete breakdown of the molecules into their constituting atoms, further characterized by their immediate neighbour atoms. The group contributions are calculated by means of a fast Gauss-Seidel fitting algorithm using the experimental data of 2036 molecules from literature. A ten-fold cross-validation procedure has been carried out to test the applicability of this method, which confirmed excellent quality for the prediction of the vapour pressure, expressed in log(pa), with a cross-validated correlation coefficient Q of 0.9938 and a standard deviation σ of 0.26. Based on these data, the molecules' standard Gibbs free energy ΔG° has been calculated. Furthermore, using their enthalpies of vaporization, predicted by an analogous group-additivity approach published earlier, the standard entropy of vaporization ΔS° has been determined and compared with experimental data of 1129 molecules, exhibiting excellent conformance with a correlation coefficient R of 0.9598, a standard error σ of 8.14 J/mol/K and a medium absolute deviation of 4.68%.
ISSN:1420-3049
1420-3049
DOI:10.3390/molecules26041045