Solubility determination, model evaluation and thermodynamic analysis of 2,2′,4,4′,6,6′-hexanitrobibenzyl in eleven pure solvents

The solubility of 2,2′,4,4′,6,6′-hexanitrobibenzyl in eleven pure solvents (acetone, cyclohexanone, 2-butanone, methyl acetate, ethyl acetate, benzene, chlorobenzene, pyridine, acetonitrile, 1,2-dichloroethane and 1,4-dioxane) was measured by laser dynamic method at the temperature range from 293.15 K to 333.15 K under the pressure of 101.3 kPa. The study found that the solubility of 2,2′,4,4′,6,6′-hexanitrobibenzyl is positively correlated with increasing temperature. The experimental data were correlated using four thermodynamic models: the modified Apelblat model, van't Hoff model, NRTL model, and Wilson model. The modified Apelblat model demonstrated superior correlation performance. Hirshfeld surface and molecular electrostatic potential surface analysis were also conducted to investigate the solvent-solute interaction sites and the effects of interactions on the solubility of 2,2′,4,4′,6,6′-hexanitrobibenzyl in eleven selected pure solvents. Additionally, the thermodynamic properties of the dissolution process were calculated using the van't Hoff model, and the results indicated that the dissolution of 2,2′,4,4′,6,6′-hexanitrobibenzyl in eleven selected pure solvents is an endothermic and entropy-increasing process.