Thermodynamic study of binary mixtures of 1-butyl-1-methylpyrrolidinium dicyanamide ionic liquid with molecular solvents: new experimental data and modeling with PC-SAFT equation of state.

This work is concerned with thermodynamic properties of binary mixtures composed of 1-butyl-1-methylpyrrolidinium dicyanamide ionic liquid (IL) and the following molecular solvents: n-heptane, benzene, toluene, ethylbenzene, thiophene, 1-butanol, 1-hexanol, and 1-octanol. This is the very first time when experimental data on liquid-liquid equilibrium (LLE) phase diagrams and excess enthalpies of mixing (H(E)) for these systems are reported. An impact of the molecular solvent structure on LLE and H(E) is discussed.

Excess enthalpies of mixing, effect of temperature and composition on the density, and viscosity and thermodynamic properties of binary systems of {ammonium-based ionic liquid + alkanediol}.

In the present work the excess enthalpies of butyltrimethylammonium bis(trifluoromethyl-sulfonyl)imide, [N1114][NTf2], with 1,2-propanediol, or 1,2-butanediol, or 2,3-butanediol have been measured at T = 298.15 K. Additionally, the density, ρ, and dynamic viscosity, η, for binary solutions containing ionic liquids (ILs) and alkanedioles, {butyltrimethylammonium bis(trifluoromethyl-sulfonyl)imide, [N1114][NTf2], + 1,2-propanediol, 1,2-butanediol, 2,3-butanediol} and {(2-hydroxyethyl)trimethylammonium bis(trifluoro-methylsulfonyl)imide, [N1112OH][NTf2], + 1,2-propanediol, 1,3-propanediol, 1,5-pentanediol}, at wide temperature and composition ranges at ambient pressure have been investigated.

The impact of chromophoric dissolved organic matter on the photodegradation of 17α-ethinylestradiol (EE2) in natural waters.

17α-Ethinylestradiol (EE2), the potent estrogen which forms the basic constituent of the contraceptive pill, can undergo degradation in natural waters by sunlight and via secondary reactions initiated by photo-excited dissolved organic matter. The current paper presents the findings of an investigation into the irradiation process of EE2 when dissolved in natural waters. This investigation was carried out under simulated sunlight in samples of sea, river and distilled water at a 17α-ethinylestradiol concentration of 300ngL(-1).

Miscibility of ionic liquids with polyhydric alcohols.

Liquid-liquid miscibility temperatures as a function of composition have been determined experimentally for the binary systems formed by ionic liquids ([bmim][BF(4)], [bmim][PF(6)], [emim][Tf(2)N], [bmim][Tf(2)N], [hmim][Tf(2)N]) and polyhydric alcohols (1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2,3-propanetriol, 1,2-butanediol). The impact of ionic liquid and di- or three-hydroxy alcohol characteristics focusing on the effect of the IL's anion nature, cation alkyl chain length, and alcohol structure (number of hydroxyl groups, position of the hydroxy groups in the molecule, and number of carbon atoms in the diols) is presented. It appears that all systems exhibit upper critical solution temperatures.

(18)O/(16)O isotope effect on miscibility of isobutyric acid with water.

The miscibility of isobutyric acid with water and the influence of the isotope substitution of oxygen (16O/18O) in water over a broad concentration range are reported. The system exhibits a phase diagram with an upper critical solution temperature (UCST) and a visible isotope effect thereon. The oxygen isotope substitution decreases the UCST, leading to better miscibility of isobutyric acid with water.

Isotope effects on miscibility of 1-butyl-3-methylimidazolium tetrafluoroborate with butanols.

The liquid-liquid miscibility temperatures as a function of composition and deuterium substitution have been experimentally determined for the binary mixtures of 1-butyl-3-methylimidazolium tetrafluroborate with 1-butanol, isobutyl alcohol, 2-butanol, and tert-butyl alcohol and their deuterated forms (OH/OD substitution). All systems exhibit upper critical solution temperatures (UCSTs) with a visible effect of branching in alcohols. Deuteration of alcohols in the hydroxyl group results in a decrease of the UCST of the given system and the largest shift is observed for tert-butyl alcohol.

A simple quantum statistical thermodynamics interpretation of an impressive phase diagram pressure shift upon (H/D) isotopic substitution in water + 3-methylpyridine.

In a previous work (J. Phys. Chem.

Evidence for lower critical solution behavior in ionic liquid solutions.

Lower critical solution temperatures (LCST)-type of phase diagrams, including the presence of closed loops, have been encountered for the first time in binary and quasi-binary liquid solutions of ionic liquids. Furthermore, the results constitute the first experimental support for the existence of a theoretically postulated, but never encountered, special kind of type VII phase diagram. Two distinct mechanisms are involved in the appearance of demixing upon temperature increase.