Measurement and Correlation of the Solubility of 2,6-Diaminohexanoic Acid Hydrochloride in Aqueous Methanol and Aqueous Ethanol Mixtures

Abstract

The solubility of 2,6-diaminohexanoic acid hydrochloride in three pure and aqueous alcohols (methanol and ethanol) was measured by a dynamic method with a laser monitoring technique in the temperature range from 283.15 K to 333.15 K. The solubility in the different solvents increases in the following order: water > methanol > ethanol. In binary solvents, the solubility decreases with increasing alcohol concentration. The solubility data were correlated with the combined nearly ideal binary solvent/Redlich–Kister (CNIBS/R-K) model and a modified Jouyban–Acree model. For the five solvents studied, the CNIBS/R-K model was found to provide a more accurate mathematical representation of the experimental data, while the modified Jouyban–Acree model contained provisions for correlating both solvent composition and temperature.