(692f) Ternary Phase Diagram and Phase Transformation Behaviors of Various Creatine Phosphate Sodium Hydrates

The thermodynamic stability of creatine phosphate sodium (CPS) in water–methanol system was investigated by the determination of CPS–water–methanol ternary phase diagram. The involved transformation behaviors were explored in solid-state, solutions, and vapor environment by VT-PXRD, Raman, FTIR spectroscopy and DVS. Results show that CPS can exist in three hydrate forms, namely, heptahydrates, tetrahydrates, and dihydrates, in the ternary phase diagram. These three crystal forms become the stable form in turn as the water content of the solvent mixture increases, with no anhydrate form appearing, which was seldom found in current reports. The transition points move towards higher water activity as the temperature increases. Besides, solution-mediated phase transformation could happen between tetrahydrates and dihydrates, which is influenced by solvent composition, temperature, and solid loading. While solid-state phase transformation of them couldn’t occur when heating. Heptahydrates and tetrahydrates could transform into each other through adsorption or desorption of the water vapor. The study provides a guide for the control of CPS hydrate forms in theory and in the production to obtain the commercial crystal form with high purity.