Solubility Behavior of l-Arginine α-Ketoglutarate in Ten Pure and Two Binary Water + Ethanol and Water + Acetone Solvent Systems

Abstract

The solubility data of L-arginine α-ketoglutarate (AAKG) were determined by the static gravimetric method from 283.15 to 323.15 K in 10 pure solvents (water, methanol, ethanol, isopropanol, acetone, acetonitrile, dichloromethane, ethyl acetate, 2-butanone, and 1,4-dioxane) and two water + ethanol and water + acetone binary solvent systems. According to the experimental results, their solubility positively correlated with the temperature. In the selected solvent systems, there was no polymorph found. In addition, the data analysis results showed that the polarity, hydrogen bond, Hildebrand solubility parameters, and molecular structure all affected the dissolution behavior. Four thermodynamic models including the modified Apelblat model, the λh model, the NRTL model, and the Apelblat−Jouyban−Acree model were used to correlate the solubility data.

Solubility Determination and Thermodynamic Modeling of L-Phenylalanine in 12 Monosolvents from 283.15 to 323.15 K

“…33 E T ( 30) is a physical property parameter considering the dielectric constant, dipole moment, and other physical properties, which can be used as a perfect empirical solvent polarity-scale reference. 34 It can be found that except for nbutanol and isobutanol, the solubility in polar protic solvents is in agreement with E T (30), and for the polar aprotic solvents, except for acetonitrile, ethyl acetate, and 1,4-dioxane, the solubility is positively correlated to E T (30) This shows that the solubility is the result of many factors and the polarity of solvents is not the only factor affecting the process of dissolution. 31,32,35 4.3.2.…”