Liquid-liquid equilibria of aqueous two-phase systems containing poly(ethylene glycols) of different molecular weight and sodium citrate

TUBÍO GISELA; PELLEGRINI MALPIEDI, LUCIANA; NERLI, BIBIANA; PICÓ, GUILLERMO

JOURNAL OF CHEMICAL AND ENGINEERING DATA

AMER CHEMICAL SOC

Lugar: Washington; Año: 2006 vol. 51 p. 209 - 212

0021-9568

The phase diagrams corresponding to systems of sodium citrate and poly(ethylene glycol) of different molecular weights (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 more asymmetric and close to the origin with an increase in poly(ethylene glycol) molecular weight.