Study on the effect of adding co-solvent (n-alkoxyethanol) to sulfolan on the toluene extraction

Liquid-liquid equilibrium data, both binodal and tie lines are presented for thepseudo-ternary systems: (sulfolane + n-alkoxyethanol) + octane + toluene at 293.15 k.the experimental liquid-liquid equilibrium data have been correlated using the nonrandomtwo liquid (nrtl), uniquac and unifac models to predict the phase compositionof the systems studied here, and the binary interaction parameters of these componentshave been calculated. the correlated tie lines have been compared with the experimentaldata. the comparisons indicate that the calculation based on both nrtl and uniquacmodels gave a good representation of the equilibrium compositions data for all systemsstudied. also othmer, tobias and hand methods satisfactorily correlated tie-line data ofthe studied systems. the agreement between the correlated and experimental results wasvery good. the solvent (25% sulfolane+75% 2-ethoxyethanol) shows a high capacity fortoluene (a distribution coecient around unity), and for this reason, it can be used forhigher recovery of aromatics at lower solvent to feed ratios and temperatures.