Liquid-liquid equilibria of aqueous two-phase systems containing ethylene oxide-propylene oxide random copolymer and ammonium sulfate

Liquid-liquid equilibria of aqueous two-phase systems, water + ammonium sul fate + ethylene oxide-propylene oxide (EOPO) random copolymer, were studied experimentally. Experimental techniques and analytical methods are describ ed. Equilibrium data at 298.15 K along with the phase diagrams are given. T he number average molecular weights of EOPO used in the three series of exp eriments were 3640, 2340, and 780, respectively. The modified NRTL model wa s extended for the calculation of the phase equilibria of H2O + EOPO + (NH4 )(2)SO4 systems with various molecular weights. The predicted results are i n good agreement with the experimental data.