A new apparatus based on the static total-pressure (staticsynthetic) method was designed and commissioned. The novelty of the apparatus involves the placement of the loading valves, allowing metering of components directly into the liquid phase of the equilibrium cell. The new apparatus was tested and the experimental procedure developed by measuring phase equilibrium data (T−P−z) for a number of different systems available in the literature. Three of these test systems are presented in this paper, namely, the binary systems of n-hexane + 2-butanol, n-pentane + 2-butanol, and n-pentane + ethanol at temperatures of 329.21, 317.17, and 303.11 K, respectively. The modeled data (T−P−x) compare well to data available in the literature. New T−P−z data were measured for the binary system of n-pentane + 2-propanol at temperatures of 313.11, 323.11, and 333.12 K. The T−P−x−y data were modeled using both the combined and direct method.
The present work focuses on the application
of a deep eutectic
solvent (DES) to the separation of liquid mixtures. Experimental activity
coefficients at infinite dilution γ13
∞ of 23 organic solutes in tetrapropylammonium
bromide +1,6-hexanediol DES were measured by gas–liquid chromatography
(GLC) at four temperatures ranging from (313.15 to 343.15) K and atmospheric
pressure. The hydrogen bond acceptor-to-hydrogen bond donour molar
ratio was 1:2. The effect of molecular structure on the values of
γ13
∞ was also examined. From experimental limiting activity coefficients,
values of partial molar excess enthalpy at infinite dilution (ΔH
i
E,∞) were obtained using
the Gibbs–Helmholtz equation over the same temperature range.
Furthermore, infinite dilution selectivity (S
ij,s
∞) and capacity (k
j,s
∞) for various practical separation problems
were calculated from experimental γ13
∞ and were compared with those
of previously investigated ionic liquids and popular industrial solvents.
It was observed that the investigated deep eutectic solvent would
be an effective separation agent for mixtures of alkanes and thiophene
or pyridine, as well as those involving alcohols and cycloalkanes
or aromatics or ketones.
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