Solubility Determination and Thermodynamic Modeling of Phenprobamate in 12 Pure Solvents from 283.15 to 323.15 K

In this work, the solubility of phenprobamate in water, acetone, 2-butanone, methyl acetate, ethyl acetate, methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, and 1-pentanol was determined by a static gravimetric method at temperatures ranging from 283.15 to 323.15 K under atmospheric pressure. The solubility magnitudes increase monotonously with the increase of temperature in each solvent. The solubility is roughly ranked as propanone > methyl ethyl ketone > acetic acid methyl ester > ethyl acetate > water in non-alcohol solvents and methanol > 1-pentanol > sec-butanol > ethanol > n-butanol > n-propanol > isopropanol in alcohols. The solubility of phenprobamate could be ultimately determined by the combined influence of solvent polarity, hydrogen bond acceptor propensities, solvent–solvent intermolecular interactions, and spatial steric hindrance. In addition, the solubility data were correlated by the Apelblat model and the Yaws model. The outcomes show that the two models could both satisfactorily fit the experimental data, in which the Yaws model is more appropriate to correlate the solubility of phenprobamate compared with the Apelblat model. The data reported in this work contribute to the further crystallization and separation process of phenprobamate.