Measurements and Modeling of Liquid–Liquid Equilibrium of Polyethylene Glycol 400, Sodium Phosphate, or Sodium Citrate Aqueous Two-Phase Systems at (298.2, 308.2, and 318.2) K

Abstract

Experimental equilibrium data were obtained for aqueous two-phase systems composed of polyethylene glycol 400 g·mol–1 + sodium phosphate, and polyethylene glycol 400 g·mol–1 + sodium citrate, at T = (298.2, 308.2 and 318.2) K. For the system formed by sodium phosphate, at the studied range, the temperature effect on the position of the binodal curves was not relevant. For the system composed of sodium citrate, the temperature increase caused an expansion of the biphasic region. The efficacy of the salts in inducing phase segregation follows the order sodium phosphate > sodium citrate at temperatures of (298.2 and 308.2) K. Energy interaction parameters for the NRTL and UNIQUAC models were estimated, and the mean deviations between experimental and calculated compositions were 0.46 % and 0.32 %, respectively. These results show that both models, NRTL and UNIQUAC, are able to represent the phase behavior of polymer–salt aqueous two-phase systems evaluated.

Aqueous two-phase system (polyethylene glycol + ionic liquid) for extraction of α-amylase: phase diagrams, systems characterization and partition study

“…From the analysis of the binodal data, it was found that, as the temperature increases, the solubility of PEG increases, i.e., lower temperatures are favorable for the formation of the two phases. This behavior is in agreement with that found by Freire et al (2012) Souza et al (2013) when studying systems formed by PEG 400 and sodium citrate and PEG 400 and sodium phosphate.…”

Novel aqueous biphasic system based on ethyl lactate for sustainable separations: Phase splitting mechanism

“…Extraction and purification of catechins is a challenging task [22]. [23] which showed a good agreement of less than 1% deviation between measured and literature mass fraction data. The validity of the experimental method for the cloud points was further confirmed by carrying out replicas of the assays at random conditions.…”

Density, Refractive Index, pH, and Cloud Point Temperature Measurements and Thermal Expansion Coefficient Calculation for PPG400, PE62, L64, L35, PEG400, PEG600, or PEG1000 + Water Systems

“…In the literature, aqueous polymer systems were studied with PPG 400 , random and block copolymers, such as Ultraric PE62 and Pluronics L64 and L35, and PEG 400 , PEG 600 , and PEG 1000 because these compounds present advantages such as regenerability due to thermoseparation efficiency, low or controlled toxicity, nonflammability, and commercial availability …”

“…In the literature, aqueous polymer systems were studied with PPG 400 , 37 random and block copolymers, such as Ultraric PE62 38 and Pluronics L64 39 and L35, 40 and PEG 400 , 41 PEG 600 , 42 and PEG 1000 43 because these compounds present advantages such as regenerability due to thermoseparation efficiency, 38 low or controlled toxicity, 44 nonflammability, 45 and commercial availability. 46 However, regarding thermophysical properties for aqueous systems composed by these polymers, density (ρ) measurements were reported for aqueous solutions of PPG 400 , 11,47 L64, 48 PEG 400 , 49−51 PEG 600 , 47,50 and PEG 1000 , 51,52 while no such data were not found for PE62 and L35.…”