Solubility Measurement, Correlation, and Molecular Interactions of 3-Methyl-6-nitroindazole in Different Neat Solvents and Mixed Solvents from T = 278.15 to 328.15 K

Solubility and thermodynamic data of 3-methyl-6-nitroindazole in eight pure solvents and three mixed solvents were obtained experimentally via the static equilibrium method within the temperature range of (278.15-328.15) K under atmospheric pressure. Whether in a pure solvent system or a mixed system, the results show that mole fraction solubilities of 3-methyl-6-nitroindazole increased with increasing temperature. The maximum mole fraction solubilities of 3-methyl-6-nitroindazole were recorded in neat N,N-dimethylformamide and the minimum in water. The molecular interactions of 3-methyl-6-nitroindazole with solvents were determined by the determination of activity coefficients of 3-methyl-6-nitroindazole. Among the three groups of mixed solvents measured, the molar fraction of 3-methyl-6-nitroindazole in (DMF + water) system is the maximum. The experimental solubility values of 3-methyl-6-nitroindazole were fitted well with five versatile models with an R² value of >0.99.