Mohammed Taghi Zafarani-Moattar - Physical Chemistry Department, University of Tabriz, Tabriz, Iran
Dariush Nikjoo

The complete phase diagram was determined for the Na2SO4–PEGDE–H2O system at 298.15K using PEGDE (poly(ethylene glycol) dimethyl ether)with a molecular weight of 2000. Compositions of the liquid–liquid and the liquid–liquid–solid equilibria were determined using calibration curves of refractive index of the solutions, and atomic absorption (AA) and X-ray diffraction analyses were made on the solids. The solid phase in equilibrium with the biphasic region was anhydrous Na2SO4. The binodal curves were fitted using Merchuk equation. Also, the tie lines compositions were fitted to the Othmer-Tobias equation.The effects of temperature (288.15, 298.15, 30815 and 318.15) K on the binodal curve were also studied.

liquid-liquid equilibrium, Binodal, tie-line, PEGDE, Sodium Sulfate