NaSCN behaviour in acetone-methanol mixture by vapor-liquid equilibrium experiments and nuclear magnetic resonance spectroscopy results of preferential solvation

Vapour-liquid equilibrium measurements in acetone - methanol - NaSCN system at different salt molarities were performed at atmospheric pressure to emphasise the anomalous crossover effect between salting-in and salting-out on the acetone, reported previously at different salt mole fractions. In addition. H-1, Na-23 and C-13 NMR chemical shifts were measured in acetone - methanol mixture in the presence of sodium thiocyanate at various salt molarities to study the preferential solvation of ions (cation and anion) in the mixed solvent. The anion chemical shift reveals preferential solvation for methanol. Concerning the cation chemical shift, a particular behaviour of this mixture was observed and interpreted by the preferential solvation by acetone in the methanol-rich regions and by methanol in the remaining regions. The solvation of sodium in these mixtures was shown to depend strongly on the solvent-solvent interactions. A comparison between spectroscopic studies of ion solvation and vapour-liquid equilibrium experiments was presented.