Liquid−Liquid and Solid−Liquid Equilibria of the Poly(ethylene glycol) + Sodium Sulfate + Water System at 298.15 K

Abstract

Liquid−liquid and solid−liquid equilibrium data are presented for the PEG 4000 + Na 2 SO 4 + water system at 298.15 K. Six equilibrium regions were found. The binodal curve was fitted by means of a three-parameter equation (relative mean deviation 3.95%), and the tie lines compositions were fitted to both the Othmer−Tobias and Bancroft equations. Densities and refractive indices were determined for the solutions in equilibrium. Samples of the solid phase analyzed by X-ray diffraction showed it to consist of anhydrous Na 2 SO 4 .