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| Titel |
SIMPOL.1: a simple group contribution method for predicting vapor pressures and enthalpies of vaporization of multifunctional organic compounds |
| VerfasserIn |
J. F. Pankow, W. E. Asher |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 8, no. 10 ; Nr. 8, no. 10 (2008-05-29), S.2773-2796 |
| Datensatznummer |
250006151
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| Publikation (Nr.) |
 copernicus.org/acp-8-2773-2008.pdf |
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| Zusammenfassung |
| The SIMPOL.1 group contribution method is developed for
predicting the liquid vapor pressure poL (atm) and
enthalpy of vaporization Δ Hvap (kJ mol-1) of
organic compounds as functions of temperature (T). For each compound i, the
method assumes log10poL,i (T)=∑kνk,ibk(T) where νk,i is the
number of groups of type k, and bk (T) is the contribution to log10poL,i (T) by each group of type k. A zeroeth group is
included that uses b0 (T) with ν0,i=1 for all i. A total of
30 structural groups are considered: molecular carbon, alkyl hydroxyl,
aromatic hydroxyl, alkyl ether, alkyl ring ether, aromatic ether, aldehyde,
ketone, carboxylic acid, ester, nitrate, nitro, alkyl amine (primary,
secondary, and tertiary), aromatic amine, amide (primary, secondary, and
tertiary), peroxide, hydroperoxide, peroxy acid, C=C, carbonylperoxynitrate,
nitro-phenol, nitro-ester, aromatic rings, non-aromatic rings, C=C–C=O in
a non-aromatic ring, and carbon on the acid-side of an amide. The T
dependence in each of the bk (T) is assumed to follow b(T)=B1/T+B2+B3T+B4ln T. Values of the B coefficients are fit using an initial basis set of 272 compounds for which experimentally based
functions po L,i=fi (T) are available. The range of vapor pressure
considered spans fourteen orders of magnitude. The ability of the initially
fitted B coefficients to predict poL values is examined
using a test set of 184 compounds and a T range that is as wide as 273.15 to
393.15 K for some compounds. σFIT is defined as the average over
all points of the absolute value of the difference between experimental and
predicted values of log10poL,i (T). After
consideration of σFIT for the test set, the initial basis set
and test set compounds are combined, and the B coefficients re-optimized. For
all compounds and temperatures, σFIT=0.34: on average,
poL,i (T) values are predicted to within a factor of 2.
Because d(log10 poL,i (T))d(1/T) is related to the
enthalpy of vaporization ΔHvap,i, the fitted B provide
predictions of ΔHvap,i based on structure. |
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