Liquid-Liquid Equilibria of Aqueous Two-Phase Systems Containing Poly(ethylene glycols) of Different Molecular Weight and Sodium Citrate

TUBIO, G.; PELLEGRINI, L; NERLI, B.; PICÓ, G.

Journal of Chemical and Engineering Data

ACS

Año: 2006 vol. 51 p. 209 - 212

0021-9568

The phase diagrams corresponding to systems of sodium citrate and poly(ethylene glycol) of different molecularweights (600, 1000, 1450, 3350, and 8000) were determined at (22, 37 and 50) °C. Moreover, the medium pH(5.2, 8.2, and 9.2) effect was also studied. The binodal curves were described using a four-parameter sigmoidal equation, and the tie-lines were satisfactorily described using the Othmer-Tobias and Bancroft equations. An  increase in temperature and pH caused the expansion of the two-phase area. The binodal curves became moreasymmetric and close to the origin with an increase in poly(ethylene glycol) molecular weight.r-Tobias and Bancroft equations. An  increase in temperature and pH caused the expansion of the two-phase area. The binodal curves became moreasymmetric and close to the origin with an increase in poly(ethylene glycol) molecular weight.