QUATERNARY LIQUID-LIQUID EQUILIBRIA OF SYSTEMS WITH 2 PARTIALLY MISCIBLE SOLVENT PAIRS - 1-OCTANOL PLUS 2-METHOXY-2-METHYLPROPANE PLUS WATER PLUS ETHANOL AT 25-DEGREES-C

Liquid-liquid equilibrium (LLE) data were determined for the quaternar y system 1-octanol + 2-methoxy-2-methylpropane (MTBE)+ water + ethanol . at 25 degrees C and atmospheric pressure. The full range of composit ions was covered by using pseudoternary systems, each one correspondin g to a plane in the tetrahedral phase diagram. The tie-lines for the q uaternary mixtures did not always lie within the plane for the corresp onding pseudoternary system. The LLE data for the quaternary system, a nd for its constituent ternary subsystems, were correlated using the N RTL (alpha = 0.1, 0.2 or 0.3), UNIQUAC and TK-Wilson equations. Each c orrelation afforded similar binary interaction parameters for the part ially miscible pairs common to the ternary subsystems. Moreover, these parameters differed little from those obtained for these solvent pair s in the quaternary system. The LLE data were predicted using the UNIF AC method and also using the above-mentioned correlation equations, fi xing each binary interaction parameter to the value or mean value obta ined by correlating the LLE data for the constituent ternary subsystem s. (C) 1998 Published by Elsevier Science B.V. All rights reserved.