Predicting infinite dilution activity coefficients of organic compounds in water by quantum-connectivity descriptors

Abstract

Quantitative structure-property relationship (QSPR) models are developed to predict the logarithm of infinite dilution activity coefficient of hydrocarbons, oxygen containing organic compounds and halogenated hydrocarbons in water at 298.15 K. The description of the molecular structure in terms of quantum-connectivity descriptors allows to obtain more simple QSPR models because of the quantum-chemical and topological information coded in this type of descriptors. The models developed in this paper have fewer descriptors and better statistics than other models reported in literature. The current models allow a more transparent physical interpretation of the phenomenon in terms of intermolecular interactions which occur in solution and which explain the respective deviations from ideality.

Microstructure and fracture behavior of polypropylene/barium sulfate composites

“…In 1975, Randić proposed a structural descriptor called branching index 1 that later became the well‐known Randić (connectivity) index, which is the most used molecular descriptor in structure‐property and structure‐activity relationships studies 2–5. Recently, Randić index is interpreted as the relative molecular area of external accessibility that is the sum of relative accessibility bond areas in a molecule in 6. Mathematical properties of this descriptor have also been studied extensively as summarized in 7, 8.…”

Infinite Dilution Activity Coefficients as Constraints for Force Field Parameterization and Method Development

“…5 Techniques such as gas-liquid chromatography, 5,10 high-performance liquid chromatography 10 and differential ebulliometry 5,10,11 are traditionally used to measure activities in extremely dilute systems at varying concentrations, leading to the infinite dilution activity coefficient by extrapolation. 10 There has been considerable interest in predicting these coefficients [5][6][7][10][11][12][13][14][15][16][17][18][19][20][21] due to their use in phase equilibria studies in chemical engineering applications. [2][3][4]14 IDACs (also represented by γ ∞ ) are related to solvation free energies by the following equation: 6,7,13…”

QSPR analysis of infinite dilution activity coefficients of chlorinated organic compounds in water

“…Alternatively, the quantitative structure-property relationship (QSPR) provides a promising method for the estimation of ∞ based on descriptors derived solely from the molecular structure to fit experimental data [14][15][16][17][18]. The QSPR is based on the assumption that the variation of the behavior of the compounds, as expressed by any measured physicochemical properties, can be correlated with numerical changes in structural features of all compounds, termed "molecular descriptors" [19][20][21][22][23].…”

“…He and Zhong [16] have applied the molecular connectivity indices to develop QSPR models for ln( ∞ ) of hydrocarbons, oxygen containing organic compounds and halogenated hydrocarbons in water, respectively. With the same dataset, Delgado and co-workers [18] recently obtained several QSPR equations for the prediction of ln( ∞ ) by using quantum-chemical descriptors. However, the abovementioned QSPR models have not been evaluated with the external validation set.…”

“…In fact, validation is a crucial aspect of any QSPR/QSAR (quantitative structure-activity relationship) modeling [24]. Furthermore, all authors tried to develop their QSPR models based on a special group of molecular descriptors (connectivity indices in the work of He and Zhong [16], quantum-chemical descriptors in the work of Delgado et al [15,18]). This phenomenon caused the obtained results are not the best results which can be obtained by QSPR analysis.…”