Solid-liquid equilibria in systems consisting of potassium pseudohalides and amides

Abstract

Within the framework of this research, we measured solid–liquid equilibrium diagrams of binary systems of potassium thiocyanate or potassium selenocyanate in {formamide, or N-methylformamide, or N,N-dimethylformamide} as functions of temperature, using the cloud-point and DSC techniques over the full concentration range. The temperatures varied approximately between 220 and 450 K. As a next step, we determined limited solubility data for the potassium cyanate with {formamide or N-methylformamide}. We then correlated the data by the thermodynamic solubility equations with the solute activity coefficients represented by the Redlich-Kister model. Finally, we proceeded to calculate the coordinates of the invariant points, and discussed the observed phenomena.