Study on Phase Equilibria of CdCl₂–l-Proline (trans-4-Hydroxy-proline)–H₂O and the Standard Molar Enthalpy of Formation of Cd(C₅H₉NO₂)Cl₂·H₂O and Cd(C₅H₉NO₃)Cl₂

Abstract

The solubility of the ternary system of CdCl 2 −L-proline (trans-4-hydroxy-proline)−water at 298.1 K was studied by the isothermal dissolution equilibrium method, and two ternary phase diagrams were drawn. Two double salts (Cd(C 5 H 9 NO 2 )Cl 2 • H 2 O and Cd(C 5 H 9 NO 3 )Cl 2 ) were synthesized, and both of them were characterized by XRD and TG−DTG. In addition, via designing thermochemical cycles and measuring their enthalpy of solution, the standard molar enthalpies of formation of Cd(C 5 H 9 NO 2 )Cl 2 •H 2 O and Cd(C 5 H 9 NO 3 )Cl 2 at 298.15 K were obtained, which were −1225.92 ± 2.19 and −1073.06 ± 1.87 kJ• mol −1 , respectively.