Solid–Liquid Equilibrium (SLE) of the N,N-Dimethylacetamide (DMA) + MCl (M = Na, K, Rb, and Cs) + Water Ternary Systems at Multiple Temperatures

Abstract

We report herein the solid–liquid equilibria (SLE) of N,N-dimethylacetamide (DMA) + MCl (M = Na, K, Rb, and Cs) + H2O ternary systems for the first time. At the three given temperatures (T = 298.15 K, 308.15 K, and 318.15 K), the solubilities, densities, and refractive indices for these ternary systems are determined with the mass fraction of DMA in salt-free solvent system ranging from 0.0 to 1.0. The solubility of salts decreases significantly with the addition of DMA, and the salting-out ratios are calculated accordingly. The nonrandom two-liquid (NRTL) model can effectively fit the experimental solubility. Furthermore, to investigate the temperature effect on the SLE, the dynamic solubility measurement system is selected to determine the solubility of the salts in the mixed solvent (w DMA = 0.3, 0.5, and 0.7) with the temperature continuously increased. The solubility data at multiple temperatures are well fitted by the modified Apelblat equation and the λh equation.

Phase Behavior of N-Methylpyrrolidone + MCl (M = Na, K, Rb, Cs) + H2O Systems at 288.2, 298.2, and 308.2 K

“…The comparison of the solubilities, densities, and refractive indices of the four salts NaCl/KCl/RbCl/CsCl in pure water are in good agreement with the literature values ,,,− (Tables S1–S3 and Figures S1–S3). The experimental values of solubility, density, and refractive index of all the saturated solutions of the NMP + NaCl/KCl/RbCl/CsCl + H 2 O ternary system are listed in Table and graphically shown in Figures – .…”

“…In our previous works, the phase equilibria (LLE and SLE) of the ternary systems containing alkali metal salts, especially Rb and Cs, such as NaCl/KCl/RbCl/CsCl + amide + water − and RbBr/CsBr + FA/NMF/DMF + H 2 O were discussed. N -Methylpyrrolidone (NMP) is an important organic solvent both in a laboratory and in the industry. − NMP is a water-miscible strongly polar (μ = 4.09 D) aprotic solvent with a high boiling point (202 °C, 100 kPa).…”

Phase Diagrams and Physicochemical Properties for the Ternary System (CsCl + NaCl + H2O) at T = (298.15, 308.15, and 318.15) K

“…The solubility, density, and refractive index of CsCl and NaCl saturated aqueous solutions in this work were compared with values in the literature − as listed in Table . The results showed good agreement.…”

Measurement and Correlation of Solubilities and Solution Thermodynamics for N,N-Diethylformamide + MCl (M = Na, K, Rb, and Cs) + Water Systems in the Temperature Range 288.15–338.15 K

“…The isothermal solubility data of salts in the mixed solvent, the density and refraction index of the solution at 288.15, 298.15, and 308.15 K are listed in Table and graphically shown in Figures –. Moreover, the solubility, density, and refractive index of the salts in pure water were compared with literature. − The result is listed in Table S1 and graphically given in Figure S1. The maximum deviation of the measured properties is lower than 0.3%.…”

“…The isothermal solubility of MCl in the solution ( w salt ) was determined by Mohr’s method and the deviation of three measurements was estimated to be within 0.5%. The multiple temperature solubility of MCl in the solution ( w salt ) was measured by a turbidity instrument utilizing a laser monitoring installation . Meanwhile, the binodal curves were studied by the cloud point method .…”