Solid-Liquid Phase Equilibria of the Ternary System (NaCl + CH₃OH + H₂O) at 298.15, 308.15, 318.15 K, and 0.1 MPa

Abstract

The phase equilibrium of the ternary system (NaCl + CH3OH + H2O) at 298.15, 308.15, 318.15 K, and 0.1 MPa has been investigated by the isothermal dissolution equilibrium method. Solubilities and physicochemical properties including refractive index (nD) and density (ρ) in the ternary system were determined experimentally. According to the experimental data, the phase diagrams and diagrams of physicochemical properties versus sodium chloride concentration in the solvents at 298.15, 308.15, and 318.15 K were plotted, respectively. The experimental results showed that the system did not cause stratification and the equilibrium solid phase was anhydrous sodium chloride. Neither double salt nor solid solution was found at the three temperatures. The physicochemical properties of the ternary system change regularly with the increase of sodium chloride concentration in the solution, and the solvation effect of CH3OH on NaCl was significant. Moreover, the calculated values of NaCl solubility data based on the CNIBS/R-K equations agreed well with the experimental results, and the thermodynamic functions in the dissolution process of NaCl in the CH3OH-H2O binary system were also calculated for further investigation of NaCl dissolution process.

Activity Coefficients and Solubilities of NaCl in Water–Methanol Solutions from Molecular Dynamics Simulations

“…Figure shows the solubility of NaCl in the ternary systems calculated from the simulations compared to experimental data. As shown in the figure, the predicted solubility results agree reasonably well with the experimental data. , This is notable, since most fixed-charge nonpolarizable force fields are unable to predict simultaneously MIACs and solubilities . The JC + SPC/E model combination underpredicts salt solubility in pure water by around 50%.…”

“…(Top panel) Simulation results (blue circles) for the solubility of NaCl in the NaCl + water + methanol ternary system at 298.15 K and 1 bar compared to experimental data: green triangles and red stars from refs and , respectively. Weight fractions in this plot include the salt.…”

“…It is a natural question to ask whether these techniques and the underlying force field parameters perform well for mixed-solvent solutions. Salt solutions in water–alcohol mixed solvents have been the subject of prior experimental and theoretical studies. − It has been shown experimentally that the addition of alcohols to the aqueous salt solutions decreases the salt solubility (“salting-out” effect). − Furthermore, the addition of salt to a number of water–alcohol binary solutions which are totally miscible in the absence of salt also leads to liquid–liquid phase separation. Ternary solutions of salt + water + an alcohol are of particular interest in many technological applications including crystallization, liquid–liquid extraction, and hydrometallurgical process, to name a few.…”

“…A prominent such example is the NaCl + water + methanol ternary system which is frequently present in separation processes . The experimental ternary phase diagram (Shi et al) shows a sharp decline in solubility when moving from pure water to pure methanol as solvent. Furthermore, there is a downward shift in the corresponding MIACs where the Debye–Hückel limiting slope falls much more sharply at higher methanol contents.…”