Nicotinamide Solubility in Ethanol + Acetonitrile at Different Temperatures

In the current study, the solubility of nicotinamide in all fractions (with 0.1 intervals) of acetonitrile and ethanol mixtures was gravimetrically determined. The results show that maximum solubility was obtained in ethanol mass fraction of 0.8 (xm=8.52×10-2) at 313.2 K and the minimum solubility in the pure acetonitrile (xm=7.33×10-3) at 293.2 K. In the next step, all data are fitted/back-calculated by several mathematical cosolvency equations. Deviation amount of back-calculated data from experimental values (<5.0%) shows the applicability of the models for the prediction of solubility. Also, density data for saturated systems are determined and fitted to the adopted form of the Jouyban-Acree model which obtained a back-calculated MRD% of 0.7%. Furthermore, the thermodynamic behavior of nicotinamide in investigated mixtures was investigated using the calculation of the Gibbs energy, enthalpy, and entropy at Thm. Further, inverse Kirkwood-Buff integrals calculations demonstrated preferential solvation of nicotinamide by acetonitrile in acetonitrile-rich solutions.