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We report experimental data showing the effect of temperature on polymer partitioning in the dextran (DEX500) -polyethylene glycol (PEG8000) -water system. Increasing temperature increases the concentration of PEG in the top phase and decreases the concentration of DEX in the bottom phase. A solution thermodynamic model based on local compositions with temperature-dependent parameters correlates the experimental data well, and an efficient Gibbs-free energy minimization algorithm for phase equilibrium calculations is described. The partial molar enthalpies and entropies of each of the solutes, calculated with the model, are negative and decrease in magnitude as temperature increases.

In this paper, experimental data on the phase behavior of the binary system (methane + 5-α-cholestane) are presented. Experiments were carried out according to the synthetic method. The temperature range investigated was from 320 K to 450 K. The pressures applied did not exceed 250 MPa. Vapor−liquid equilibria have been measured for 18 different mixtures. Additionally, the melting curve of pure 5-α-cholestane and the course of the three-phase curve (solid 5-α-cholestane + liquid + vapor) was determined. The second critical end point was located at a temperature T = (342.2 ± 0.5) K, a pressure p = (193.3 ± 0.4) MPa, and a mole fraction of 5-α-cholestane in the critical fluid phase x = 0.049 ± 0.004.