The salting out action of alkali metal nitrates on the water-diethylamine binary system

Abstract

The results of a polythermal study of the salting out action of alkali metal (Na, K, and Cs) nitrates on the water-diethylamine binary system characterized by stratification with a lower critical solution point (LCSP) were comparatively analyzed. Alkali metal nitrates experiencing homoselective solvation in aqueousorganic solvents were found to decrease the LCSP of this binary system, that is, have a salting out action. A decrease in the radius of the cation in the series CsNO3-KNO3-NaNO3 decreased the temperature of critical tie line formation in the monotectic state of salt-water-diethylamine ternary systems (69.3, 48.1, and 22.9°C, respectively). In all ternary systems, first and foremost in the system with potassium nitrate, the effect of diethylamine salting out from aqueous solutions grew stronger as the temperature increased. The conclusion was drawn that, among the salts studied, sodium nitrate had the strongest salting out effect at 22.9–88.4°C, and potassium nitrate, at 88.4–150.0°C.