Liquid-liquid equilibria of water/1-propanol/methyl ethyl ketone/potassium chloride

Abstract

The liquid-liquid equilibrium of water/1-propanol/methyl ethyl ketone (MEK) at 25°C was significantly modified by the presence of dissolved potassium chloride. Water is salted out of the organic phase while MEK is more preferentially salted out of the aqueous phase than 1-propanol. These results in considerable enlargement of the two-phase region and enhancement of the extractive efficiency of MEK for the separation of 1-propanol from its aqueous mixture. Good correlation of the liquid-liquid equilibria (LLE) of the system in the presence of potassium chloride up to saturation was obtained with Tan's modified NRTL phase model for multicomponent solute-solvent mixtures with the solute-solvent interaction parameters expressed as a third-order polynomial function in salt concentration. Similar to the observation reported for vapour-liquid equilibrium (VLE) of solvent-solute mixtures, salting-in and salting-out of the solvent components from the respective phases can be predicted according to the relative solute-solvent interaction parameters of the solvent components in the two phases. © 2001 Elsevier Science B.V. All right reserved.