Equilibrium Solubility and Solvent Effect Study of 3-Nitrosalicylic Acid in Different Monosolvents Covering Temperatures from 278.15 to 323.15 K

Abstract

The measurement of equilibrium solubility for 3-nitrosalicylic acid in 13 monosolvents such as methanol, N,N-dimethylformamide (DMF), isobutanol, ethanol, ethylene glycol (EG), N-methyl-2-pyrrolidinone (NMP), n-propanol, ethyl acetate, isopropanol, water, n-butanol, acetonitrile, and 1,4-dioxane was made by the saturation shake-flask technique covering temperatures from 278.15 to 323.15 K under p = 101.2 kPa. As the studied temperature increased, the mole fraction solubility of 3-nitrosalicylic acid increased and had a decreasing tendency in the following order: NMP > DMF > ethyl acetate > methanol > ethanol > n-propanol > acetonitrile > isopropanol > n-butanol > EG > isobutanol > 1,4-dioxane > water. The solvent effects, such as solvent–solute and solvent–solvent molecular interactions, were further examined by the linear solvation energy relationships. Then, the equilibrium solubility magnitudes were correlated with thermodynamic models and semiempirical equations, namely, Wilson, Apelblat, λh, and NRTL. The calculated maximum value of root-mean-square deviation was 182.0 × 10–4, and the maximum value of relative average deviation was 7.24 × 10–2. In general, the obtained relative average deviation values with the Apelblat equation were smaller than those with the other equation/models for a fixed monosolvent. Finally, the mixing solution properties, activity coefficient, and partial molar excess enthalpy at infinite dilution were determined with the help of the Wilson equation.