Measurement and Correlation of l-Phenylalanine Benzyl Ester Hydrochloride Solubility in 11 Individual Solvents and a Methanol + Acetone Binary Solvent System from 283.15 to 323.15 K

The mole fraction solubility data of l-phenylalanine benzyl ester hydrochloride in 11 neat solvents including, methanol, ethanol, n-propanol, n-butanol, n-pentanol, i-butanol, i-propanol, water, acetone, acetonitrile, and ethyl acetate, as well as one binary mixed solvent of methanol + acetone were measured using the static gravimetric method at a temperature interval of "T = 283.15–323.15 K" and a pressure of "p = 98.8 kPa". The powder X-ray diffraction test was employed to identify the solid-phase characterization of l-phenylalanine benzyl ester hydrochloride in the investigated solvent systems. At constant solvent composition, the solubility was positively correlated with temperature. In the selected monosolvents, the solubility of l-phenylalanine benzyl ester hydrochloride was restricted by multiple factors, and the following order was obtained: methanol > ethanol > n-propanol > n-butanol > n-pentanol > i-butanol > i-propanol > acetone > acetonitrile > ethyl acetate (except for water, which intersects with other solvents). In addition, the modified Apelblat model and the Apelblat–Jouyban–Acree model were employed to fit the solubility data.