Density,refractive index and liquid–liquid equilibrium data of polyethylene glycol 3000 + potassium formate + water at different pH values

New liquid–liquid equilibrium data for polyethylene glycol(PEG) 3000 + CHO_2K + H_2O systems were measured at 298.15 K and pH values of 7.95, 8.40 and 9.98. It was found that an increase in pH caused the binodal curve to be displaced downward and the two-phase region to expand. Accordingly, the binodal curve was adjusted to the Pirdashti equation and the tie-line compositions were correlated using the Othmer–Tobias, Bancroft and Hand equations. The study measured the refractive index and densities of several homogeneous binary and ternary solutions. The solutions were used for calibration within a range of 0% to 30% of the mass of the PEG and potassium formate. The density and refractive index data show a linear variation with the mass fraction of the polymer and the salt. The effect of pH on the binodal, tie-line lengths(TLL) and slope of the tie-line(STL) in the systems was examined. It was found that an increase in pH increased the TLL and decreased the STL. It was observed that the density of the aqueous two-phase system was influenced by the TLL. The difference in density between phases(Δρ) increased as the TLL and pH increased. It was found that the TLL and Δρ showed a linear relationship. The effective excluded volume(EEV) of the PEG was obtained and it was found that EEV also increased as the pH increased.

Density,refractive index and liquid-liquid equilibrium data of polyethylene glycol 3000 + potassium formate + water at different pH values

New liquid-liquid equilibrium data for polyethylene glycol (PEG) 3000 + CHO2K + H2O systems were measured at 298.15 K and pH values of 7.95,8.40 and 9.98.It was found that an increase in pH caused the binodal curve to be displaced downward and the two-phase region to expand.Accordingly,the binodal curve was adjusted to the Pirdashti equation and the tie-line compositions were correlated using the Othmer-Tobias,Bancroft and Hand equations.The study measured the refractive index and densities of several homogeneous binary and ternary solutions.The solutions were used for calibration within a range of 0％ to 30％ of the mass of the PEG and potassium formate.The density and refractive index data show a linear variation with the mass fraction of the polymer and the salt.The effect of pH on the binodal,tie-line lengths (TLL) and slope of the tie-line (STL) in the systems was examined.It was found that an increase in pH increased the TLL and decreased the STL It was observed that the density of the aqueous two-phase system was influenced by the TLL The difference in density between phases (△ρ) increased as the TLL and pH increased.It was found that the TLL and △ρ showed a linear relationship.The effective excluded volume (EEV) of the PEG was obtained and it was found that EEV also increased as the pH increased.