Solubility measurement, thermodynamic modeling, and molecular dynamic simulation of glycylglycine in five binary solvents

Abstract

Glycylglycine (Gly–Gly) is a crucial biochemical reagent widely used in cosmetics, food additives, and medicine. Using the equilibrium method, the solubility data of Gly–Gly in four binary solvents (ethanol/isopropanol/ethanediol/acetone + water) were investigated at temperatures over a range of 288.15–328.15 K under 101.3 kPa, as well as in the binary solvent of acetic acid + water from 293.15 to 333.15 K. The solubility data were correlated by Apelblat-Jouyban Acree, Van’t Hoff-Jouyban Acree, and CNIBS/Redlich-Kister models. Additionally, the radial distribution function was obtained through molecular dynamic simulation. It presented the unusual dissolution behavior of Gly–Gly in acetic acid and water mixture. The apparent thermodynamic properties, including standard enthalpy, Gibbs free energy, and entropy change of dissolution, were obtained accordingly. This article could help the industrial crystallization of Gly–Gly.