Equilibrium solubility, solvent effect and preferential solvation of 5-nitrofurazone (form γ) in aqueous co-solvent mixtures of isopropanol, N-methyl pyrrolidone, ethanol and dimethyl sulfoxide

Solubilities of 5-nitrofurazone (form γ ) in aqueous co-solvents mixtures of isopropanol, N -methyl pyrrolidone (NMP), ethanol and dimethyl sulfoxide (DMSO) were experimentally investigated via the saturation shake-flask technique at temperatures from 278.15 K to 323.15 K under ambient pressure of p  = 101.2 kPa. The solubility of 5-nitrofurazone increased to a maximum value with 100% mass fractions of NMP and DMSO in aqueous solutions of NMP and DMSO, while with 80% mass fractions of isopropanol and ethanol in aqueous solutions of isopropanol and ethanol. The solids equilibrated with liquor were characterized by X-ray power diffraction, indicating that no solvate formation or polymorphic transformation occurred. The Jouyban-Acree model was accepted to correlate the obtained solubility. The acquired highest relative average deviation and root-mean-square deviation values were, respectively, 5.62 × 10 −2 and 11.18 × 10 −4 . Quantitative values for local mole fractions of NMP (ethanol, DMSO, DMF or isopropanol) and water nearby 5-nitrofurazone were obtained by the method of Inverse Kirkwood–Buff integrals. The parameters of preferential solvation were positive for isopropanol/ethanol in the isopropanol/ethanol mixtures in intermediate compositions, and for NMP/DMF/DMSO in the NMP/DMF/DMSO mixtures in intermediate and NMP/DMF/DMSO-rich compositions, which indicated that 5-nitrofurazone was preferentially solvated by the co-solvents. Linear solvation energy relationships were used to model the solvent effect through the analysis of correlations between solubility data and solvent polarity quantified by suitable descriptors.