Phase Equilibria of Alkali Nitrates (NaNO3, KNO3, RbNO3, CsNO3) in Glycerol + H2O System at Various Temperatures

Abstract

By using a homemade research device for phase equilibrium, the equilibrium solubility of the alkali nitrates (NaNO 3 /KNO 3 /RbNO 3 /CsNO 3 ) in the mixed solvent glycerol [HOCH 2 CH(OH)CH 2 OH] + H 2 O in the mass fraction range of glycerol (0.0 to 1.0) at 35 and 45 °C was measured. Moreover, the density and refractive index of the saturated solutions of NaNO 3 /KNO 3 /RbNO 3 /CsNO 3 + mixed solvent glycerol + H 2 O were determined. The experimental results showed that, in all systems, with the increase of mass fraction of glycerol, the solubility of the salts and the density of the solution decreased, while the refractive index increased gradually. The solubility, refractive index, and density data were fitted by a four-parameter empirical equation.