Measurement and Correlation of the Solubility and Thermodynamic Properties of Ribavirin(II) in Nine Pure Solvents and (1-Propanol + Water) Binary Solvents

The solubility of ribavirin(II) in nine pure solvents (formic acid, dimethyl sulfoxide, water, methanol, ethanol, 1propanol, 1-butanol, 2-butanol, and acetone) and a 1-propanol-water binary system was analyzed by a gravimetric method under atmospheric pressure and temperature ranging from 283.15 to 323.15 K. Experimental results show that when the temperature increases, the fractional solubility in all selected solvents also increases, and the dissolution behavior is affected by the solvent polarity. The solubility of ribavirin(II) is correlated with the modified Apelblat equation,.h model, and nonrandom two-liquid (NRTL) model, indicating that these three models can satisfactorily predict the experimental values. The modified Apelblat equation shows better fitting performance than the other models. The NRTL model was also used to calculate the mixing thermodynamic properties of ribavirin(II) solution, including mixing Gibbs energy, mixing enthalpy, and mixing entropy. The results show that the dissolution of ribavirin(II) is a spontaneous and entropy-driven process.