Aqueous two-phase system of poly(ethylene glycol) 4000 and sodium molybdate at different temperatures

Abstract

Liquid–liquid equilibrium (LLE) data for the Na2MoO4+polyethylene glycol 4000 (PEG 4000)+H2O system were determined experimentally at T=(288.15, 298.15 and 308.15)K. Additionally, experimental data of density, sound velocity, refractive index and viscosity are also reported at T=(288.15, 298.15 and 308.15)K.The effect of temperature on the binodal curves and tie-lines was studied and it was found that an increasing in temperature caused the expansion of two-phase region. The extended UNIQUAC model and the Othmer–Tobias and Bancroft equations were used to correlate the experimental tie-line data obtaining a good representation of the equilibrium. Moreover, the Merchuk equation was used to correlate the binodal curves. A good agreement between experimental and correlated values of the tie-lines was obtained.