Solubility and Thermodynamic Properties of (1R,2R)-(+)-1,2-Diaminocyclohexane L-Tartrate in Methanol (Ethanol or 2-Propanol) + Water Binary Solvents at Various Temperatures

Abstract The solubility of (1R,2R)-(+)-1,2-diaminocyclohexane L-tartrate (DHT) in methanol + water, ethanol + water, and 2-propanol + water mixed solvents were measured using a synthetic method with alcohols mass fractions varying from 0.1 to 0.5 over 278.15 to 318.15 K under atmospheric pressure ( P = 0.1 MPa). It was proved that the solubility of DHT in the three binary solvents increased with increasing temperature, while decreased with the mass fraction of alcohols rising. The experimental solubility data were correlated by the modified Apelblat equation and Sun model. The modified Apelblat model showed better agreement with the experimental data than the other model. Furthermore, the thermodynamic parameters including \(\Delta G_{{{\text{sol}}}}^{^\circ }\) , \(\Delta H_{{{\text{sol}}}}^{^\circ }\) , and \(\Delta S_{{{\text{sol}}}}^{^\circ }\) for DHT in the dissolution process were obtained from Van’t Hoff plots.