Study on 6-Bromo-2-methylquinoline in Ten Monosolvents and Four Binary Blends at 278.15–323.15 K: Solubility, Correlation, and Solvent Effect

The equilibrium solubility of 6-bromo-2-methylquinoline in various binary blends [ethanol/isopropanol/N,N-dimethylformamide (DMF)/methanol + water] and ten monosolvents (methanol, ethanol, n-propanol, isopropanol, ethyl acetate, toluene, acetone, acetonitrile, DMF, and water) was studied by the isothermal method at 278.15–323.15 K under 101.2 kPa. Among the ten pure solvents, the maximum solubility in mole fraction was obtained in toluene (3.318 × 10–2), followed by ethyl acetate (2.991 × 10–2), acetone (2.764 × 10–2), acetonitrile (2.528 × 10–2), DMF (2.220 × 10–2), n-propanol (9.141 × 10–3), isopropanol (8.123 × 10–3), ethanol (3.896 × 10–3), methanol (9.981 × 10–4), and water (2.888 × 10–5) at 323.15 K. In four solvent mixtures, the maximum and minimum solubilities were obtained in the (DMF + water) and (methanol + water) blends. The solubility of 6-bromo-2-methylquinoline in pure solvents was only affected by temperature and calculated by the Apelblat, van’t Hoff, and NRTL models. The Jouyban–Acree (J–A), van’t Hoff–Jouyban–Acree (V–J–A), and modified Apelblat–Jouyban–Acree (A–J–A) models were used to evaluate the solubility data in mixed systems. The calculation of solvent effect deeply explored the dissolution behavior of 6-bromo-2-methylquinoline from the molecular point of view, and the results showed that the interaction between the solute and solvent was dominant. The apparent thermodynamic properties of 6-bromo-2-methylquinoline in pure solvents were obtained by van’t Hoff plots.