Solubility Behavior and Synergistic Solvation Effects of N-Benzylglycine in Eleven Neat and One Binary Solvent Systems from 283.15 to 323.15 K

Abstract

The equilibrium solubility of N-benzylglycine in 11 pure solvents (methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, acetone, acetonitrile, dichloromethane, ethyl acetate, 1,4-dioxane, and water) and one binary water + ethanol solvent mixture was measured by a static gravimetric method covering the temperature range of (283.15−323.15) K. The polymorphism of N-benzylglycine was characterized via the powder X-ray diffraction test and the results indicate that no crystal form transition occurred during the dissolution process in all solvents studied. When the solvent composition is constant, the solubility of N-benzylglycine in all neat solvents and solvent mixtures is positively correlated with the experimental temperature. With the increase of the mole fraction of water at a certain temperature, the solubility curve of the binary water + ethanol solvent mixtures shows an inflection point, which may be the result of the synergistic solvation effects. The KAT-LSER model equation was used to analyze the mixed solvent system by multiple linear regression analysis to reveal the interactions between solute−solvent and solvent−solvent. In addition, the modified Apelblat model and the Apelblat−Jouyban−Acree model were utilized to correlate the solubility data.

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

“…For alcohols, it can be seen that the mole fraction solubility of Glu-Me in these solvents, from high to low, was in the order: methanol > ethanol > 2-propanol > 1-propanol at the lower temperature from 283.15 to 308.15 K, but when T > 308.15 K, this order becomes methanol > ethanol > 1-propanol > 2-propanol. The polarity is entirely consistent with the solubility order of Glu-Me in these alcohol solvents at high temperatures ( T > 308.15 K), following the principle of “similar compatibility”. , Moreover, it has been reported that the larger alkyl groups increased the hydrophobic effect, resulting in a decrease in solubility . Due to the presence of the ethyl group in the molecular structure of 1-propanol, this may result in a lower solubility value than that of 2-propanol at low temperatures ( T < 308.15).…”

“…The polarity is entirely consistent with the solubility order of Glu-Me in these alcohol solvents at high temperatures (T > 308.15 K), following the principle of "similar compatibility". 27,51 Moreover, it has been reported that the larger alkyl groups increased the hydrophobic effect, resulting in a decrease in solubility. 52 Due to the presence of the ethyl group in the molecular structure of 1-propanol, this may result in a lower solubility value than that of 2-propanol at low temperatures (T < 308.15).…”

“…In order to elucidate whether the crystal form of the substance will change before and after the solubility experiment, the powder X-ray diffraction (PXRD) analysis was performed on the raw material of Glu-Me and the equilibrated solids obtained from the solubility measurement. The detailed steps for the test sample preparation can be found in the Supporting Information and also in our previous studies. , An X-ray diffractometer (PANalytical BV X’Pert PRO MPD, Netherlands) was conducted via Cu Kα radiation (1.5406 Å) to scan the Glu-Me samples under a manipulation environment: a voltage of 40 kV, a current of 150 mA, a scanning speed of 10 °/min, and a 2θ range of 5–60°.…”

Solubility and Solvent Effect Analysis of Boc-l-glutamine in Different Solvents at Multiple Temperatures

“…Details of the raw materials used for measuring the Boc- l -glutamine solubility are given in Table , and none of the chemicals have been further purified. The mole fraction solubility of Boc- l -glutamine in pure solvents was measured by the static gravimetric method, − which has been described , and validated − in previous works. In addition, the experimental equipment and detailed procedures for solubility measurement are presented in the Supporting Information.…”

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

“…In order to determine whether the equilibrium state of solid N α -carbobenzyloxy- l -arginine changes in different solvent systems, powder X-ray diffraction (PXRD) was used to analyze the raw material and the equilibrium solid samples. The preparation method of the sample has been described in the Supporting Information and our previous work . PXRD (PANalytical B.V. X’Pert PRO MPD, Netherlands) uses an X-ray generator with Cu Ka radiation (1.5406 Å) at a scanning rate of 10° per minute, and the data were collected from 5 to 60° at 2θ degree.…”