High-accuracy QSPR models for azeotropic property prediction of binary aromatic hydrocarbon mixtures: a genetic...

Aromatic hydrocarbons such as benzene, toluene, and ethylbenzene are extensively used as solvents in coatings, resin, and artificial leather industries. Azeotropic mixtures involving these compounds are commonly encountered in chemical manufacturing, where accurate azeotropic temperature and composition are essential for designing and optimizing separation processes such as extractive and pressure-swing distillation. In this study, two quantitative structure-property relationship (QSPR) models were developed to predict the azeotropic temperature and composition of binary mixtures containing aromatic hydrocarbons using only molecular structural information. The models show excellent agreement with experimental data (R² = 0.9454 and 0.9448, $R_{\mathrm{adj}}^2$ = 0.9400 and 0.9413). Internal validation via leave-one-out cross-validation yields $R_{\mathrm{cv}}^2$ = 0.9308 and 0.9364, while external validation using an independent test set yields $Q_{\mathrm{ext}}^2$ = 0.8939 and 0.9364, indicating strong robustness and superior predictive performance compared to previously reported models.

Molecular geometries were optimized using HyperChem 8.0, employing MM + and PM3 methods. Molecular descriptors were calculated using the Online Chemical Modeling Environment (OCHEM). Binary mixture descriptors were derived from pure-component descriptors via Kay's mixing rule. The genetic function approximation (GFA) algorithm was used to select the most relevant descriptors, and predictive models were constructed using multiple linear regression (MLR). Model robustness and predictive capacity were evaluated using leave-one-out cross-validation and an external test set, with applicability domains assessed via Williams plots. All computational procedures and modeling analyses were performed using OCHEM, SPSS, and HyperChem 8.0.