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3068967 
Journal Article 
Phase diagrams, densities and refractive indexes of poly(ethylene oxide) plus organic salts plus water aqueous two-phase systems: Effect of temperature, anion and molar mass 
Chamorro Rengifo, AF; Dias Ferreira, G; Dias Ferreira, G; Hespanhol da Silva, MC; Mendes da Silva, LH 
2015 
Yes 
Fluid Phase Equilibria
ISSN: 0378-3812 
406 
70-76 
WOS:000362143400009 
The application of aqueous two-phase systems (ATPSs) at the industrial level requires systems formed by non-toxic substances to decrease the negative impact on the environment. Organic salts such as sodium citrate, sodium tartrate and sodium succinate have been utilized in order to fulfill this objective. In this work, ATPSs formed by poly(ethylene oxide), PEO, with molar mass 10,000 or 35,000 g mol(-1), organic salts and water, namely PE010000 + sodium citrate + water, PE010000 + sodium tartrate + water, PE010000 + sodium succinate + water and PE035000 + sodium citrate + water ATPSs at (283.15, 298.15 and 313.15) K have been studied. Effects of temperature, anion and polymer molar mass on the phase diagrams, as well as, the densities and refractive indexes of both phases of the ATPSs were evaluated. The segregation process was endothermic and entropically driven for all ATPSs. The biphasic region on the phase diagrams increased as the molar mass of PEO increased. In addition, the biphasic region also increased in relation to the anions studied: citrate > tartrate > succinate. The consistency of the tie-line data was ascertained by applying the Othmer-Tobias correlation. (C) 2015 Elsevier B.V. All rights reserved. 
Aqueous two-phase system; Organic salts; Poly(ethylene oxide); Phase diagram; Liquid-liquid equilibrium