Revision and Extension of a Generally Applicable Group-Additivity Method for the Calculation of the Standard Heat of Combustion and Formation of Organic Molecules

Abstract

The calculation of the heats of combustion DH°c and formation DH°f of organic molecules at standard conditions is presented using a commonly applicable computer algorithm based on the group-additivity method. This work is a continuation and extension of an earlier publication. The method rests on the complete breakdown of the molecules into their constituting atoms, these being further characterized by their immediate neighbor atoms. The group contributions are calculated by means of a fast Gauss–Seidel fitting calculus using the experimental data of 5030 molecules from literature. The applicability of this method has been tested by a subsequent ten-fold cross-validation procedure, which confirmed the extraordinary accuracy of the prediction of DH°c with a correlation coefficient R2 and a cross-validated correlation coefficient Q2 of 1, a standard deviation σ of 18.12 kJ/mol, a cross-validated standard deviation S of 19.16 kJ/mol, and a mean absolute deviation of 0.4%. The heat of formation DH°f has been calculated from DH°c using the standard enthalpies of combustion for the elements, yielding a correlation coefficient R2 for DH°f of 0.9979 and a corresponding standard deviation σ of 18.14 kJ/mol.

Revision and Extension of a Generally Applicable Group-Additivity Method for the Calculation of the Refractivity and Polarizability of Organic Molecules

“…In several earlier papers [1,7,8,[403][404][405][406][407], the present atom-groups additivity algorithm, outlined in [1], has proven its formidable versatility for the reliable prediction of up to 17 physical, thermodynamic, solubility-, optics-, charge-, and environment-related descriptors. In the present work, which is part of an ongoing project, the results of the present refractivity/polarizability calculations again demonstrate its as-yet unsurpassed accuracy and easy expandability.…”

“…The present atom-group additivity approach, on the other hand, has proven its versatility in that it is able to predict a number of properties of nearly any type of compound by means of an identical algorithm, simply using the appropriate atom-group parameters tables. Accordingly, based on the updated parameters tables in this ongoing project, we have been able to calculate the heat of combustion [403] for 30 ILs with a correlation coefficient R 2 of 1.0 and a mean average percentage deviation from experimental values (MAPD) of 0.21%, the heat of vaporization [404] of 61 ILs (R 2 =0.9615, MAPD=2.12%), the liquid viscosity [8] for 93 ILs (R 2 =0.9823, MAPD=3.24%), the surface tension [405] of 160 ILs (R 2 =0.8478, MAPD=5.1%), and the liquid heat capacity at 293K [406] of 140 ILs (R 2 =0.9986, MAPD=1.05%). In analogy to these results, the refractivity values of 228 ILs calculated by means of the atom-group parameters of Table 2 have been compared with their experimental data and collected alphabetically in Table 4, revealing a MAPD of only 0.44%.…”

“…80 years delivered a sufficient number of data to enable the creation of a basis for the prediction of several chemical descriptors of interest based on the present atom-group additivity principle. Accordingly, in analogy to the previous section, the updated parameters tables provided the group parameters for the heat of combustion [403], enabling its calculation for 99 silicon compounds with a correlation coefficient R 2 of 1.0 and a MAPD of 0.19%, for the heat of vaporization [404] for 103 (R 2 =0.8164, MAPD=10.31%), for the surface tension [405] of 18 (R 2 =0.9834, MAPD=2.62%), for the liquid heat capacity at 293K [376] of 26 (R 2 =0.9981, MAPD=2.32%), for the solid heat capacity at 293K [406] of 14 (R 2 =0.9925, MAPD=2.77%), for the standard entropy of fusion [404] of 45 (R 2 =0.7251, MAPD=15.09%), and even for the vapour pressure [407] of 9 silicon compounds (R 2 =0.9897, MAPD=7.92%). In addition to these descriptors, the present present work now provides the refractivity data for 351 silicon derivatives, alphabetically sampled in Table 5.…”

Abraham Solvation Parameter Model: Calculation of L Solute Descriptors for Large C11 to C42 Methylated Alkanes from Measured Gas–Liquid Chromatographic Retention Data

“…∆H vap,298K (kJ mol −1 ) = 6.100 + 9.537 L (9) and the group-additivity method proposed by Naef and Acree [14]:…”

“…For some published QSPR studies [2,6,8] more than 1000 different descriptors have been considered before narrowing the descriptor set down to those yielding the desired predictive accuracy. Group contribution methods [9][10][11][12][13][14][15][16], on the other hand, fragment the given molecule into atoms or functional groups. A numerical value is then assigned to each atom or fragment group.…”