Experimental and Modeling Study of the Thermodynamic Behavior and Solubility of the NH4NO3–D-Sucrose–Water Ternary System at 298.15 K

In this study, thermodynamic properties such as water activity, osmotic coefficient, and saturation points of the aqueous mixture in the system D-Sucrose + Water + ammonium nitrate (AN) were determined at 298.15 K. The measurements were carried out on the mixtures of concentrations of NH4NO3 (ranging from 0.1 to 6 mol·kg−1) and D-sucrose (from 0.1 to 4 mol·kg−1) using our hygrometric method. Powder X-ray diffraction (XRD) and attenuated total reflection–Fourier transform infrared (ATR-FTIR) spectroscopy were used to characterize the solid phases crystallized during the supersaturation of the solution. Other thermodynamic quantities such as the solute activity coefficients, excess Gibbs energies, transfer energies, and solute solubilities were calculated using the Pitzer–Simonson–Clegg (PSC) model. The results obtained indicate that at an AN concentration lower than 1 mol·kg−1, the system exhibits increasingly negative deviations from ideality, and that NH4NO3 promotes the salting-out effect of sucrose.