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

We report herein the solid-liquid equilibria (SLE) of N,N-dimethylacetamide (DMA) + MCI (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 lambda h equation.