Concentration and Temperature Dependences of 2-Chloro-3-(trifluoromethyl)pyridine Solubilities in (DMF + Tetrahydrofuran) and (DMF + Isopropanol) Mixtures

Abstract

The solubility of 2-chloro-3-(trifluoromethyl)pyridine (CTP) in (DMF + tetrahydrofuran) and (DMF + isopropanol) solvent mixtures were determined by isothermal static method within the temperature range from 273–303 K under 101.3 kPa pressure. The solubility of CTP increased with increasing temperature and the mass fraction of DMF in the binary solvent systems. On the premise of same temperature and mass fraction of DMF, the solubility of CTP in (DMF + tetrahydrofuran) was higher than that in (DMF + isopropanol). The Jouyban–Acree model, the Van’t-Hoff–Jouyban–Acree model, the modified Apelblat–Jouyban–Acree model and the Sun model were utilized to correlate the obtained experimental solubility data respectively, and the Sun model could well describe the dissolution behavior of CTP in the binary mixtures. On the basis of experimental solubility data, the dissolution enthalpy and the dissolution entropy of the dissolution process were calculated. The dissolution process of CTP in the two kind of mixed solvents was an endothermic process.