Solubility Behavior and Polymorphism of N-Acetyl-l-proline in 16 Individual Solvents from 283.15 to 323.15 K

Abstract

The mole fraction solubility data of N-acetyl-l-proline in 16 neat solvents (water, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, n-pentanol, acetone, 2-butanone, acetonitrile, dichloromethane, methyl acetate, ethyl acetate, and 1,4-dioxane) covering a temperature range of 283.15–323.15 K were measured by the static gravimetric method. The polymorphism of N-acetyl-l-proline was investigated by the powder X-ray diffraction test and the patterns show that there are two polymorphs within the studied solid–liquid equilibrium systems. The increasing temperature shows a positive effect on N-acetyl-l-proline solubility in all of the solvents and the largest increasing rate is observed in acetonitrile with an increase of 16-fold. The solubility behavior was found to be influenced by five factors including polarity, hydrogen bonding, solvent–solvent interactions, molecular construction, and viscosity. Two thermodynamic models, i.e., the modified Apelblat model and the Yaws model, were used for the correlation of solubility data. To evaluate the fitting results, the average relative deviation (ARD) and root-mean-square deviation (RMSD), as well as the Akaike information criterion (AIC) and Akaike weights, were computed for each model.

Solubility and Hansen Solubility Parameters of l-Glutamic Acid 5-Methyl Ester in 12 Organic Solvents from 283.15 to 323.15 K

“…All chemicals have been used without further purification. The solid–liquid equilibrium of Glu-Me in 12 monosolvents were studied via the static gravimetric method, , which had been verified in our previous works. − The details of the experimental procedure can be found in the Supporting Information and each data were repeated at least three times to ensure the accuracy of the calculated solubility. The mole fraction solubility ( x 1 ) of Glu-Me can be obtained by eq . …”

“…In addition, the relative suitability of the two thermodynamic models was further evaluated by the Akaike information criterion (AIC) and Akaike weights (ω i ), , which were calculated by eqs –. …”

Solubility and Hansen Solubility Parameter of Nα-Carbobenzyloxy-l-Arginine in Twelve Individual Solvents from 283.15 to 323.15 K

“…The solubility of N α -carbobenzyloxy- l -arginine in 12 solvents was determined by the static gravimetric method. The detailed process of solubility measurement has been described in the Supporting Information, which has been described and verified in our previous studies. − The mole fraction solubility of N α -carbobenzyloxy- l -arginine ( x 1 ) can be calculated using eq . …”

Solubility Behavior of l-Homophenylalanine Ethyl Ester Hydrochloride in 12 Individual Solvents from 283.15 to 323.15 K

“…The details of the chemicals used in the experiment consisting of the raw HEEH are tabulated in Table . The static gravimetric method has been described in detail and verified in our previous works. − Also, the experimental device and detailed process for the solubility measurement can be seen in the Supporting Information.…”