Thermodynamic Modeling, Hansen Solubility Parameters, and Solubility Behavior of N-Benzyloxycarbonyl-L-asparagine in Twelve Pure Solvent Systems at 283.15-323.15 K

The solid-liquid equilibrium solubility and solvent effect of N-benzyloxycarbonyl-L-asparagine in monosolvent systems (water, isopropanol, ethanol, n-propanol, isobutanol, n-butanol, acetonitrile, n-pentanol, 2-butanone, acetone, 1,4-dioxane, and methanol) were studied. The solubility of N-benzyloxycarbonyl-L-asparagine was measured by the static gravimetric method at 283.15 to 323.15 K (5 K interval). The polymorph of N-benzyloxycarbonyl-L-asparagine was investigated by powder X-ray diffraction. Experiments confirmed that the crystal form did not change during the determination of solubility. Furthermore, the results showed that the solubility of N-benzyloxycarbonyl-L-asparagine was positively correlated with the test temperature in the test solvent. The solubility of N-benzyloxycarbonyl-L-asparagine in 12 pure solvents was analyzed by Hansen solubility parameters, molecular structures, hydrogen bonds, and solvent polarity. The solubility of N-benzyloxycarbonyl-L-asparagine in 12 pure solvents was affected by many factors. The Yaws model and the modified Apelblat model were employed to correlate the experimental solubility, and the fitting results of the two models were very good. In addition, AIC values and Akaike weights of the two models were calculated to evaluate the fitting level.