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Ionic liquids are the basis of a potential alternative to conventional processes based on aqueous amines currently used for carbon dioxide capture. Mixtures of ionic liquids offer an additional degree of tailoring over the intrinsic tunable properties of "single" ionic liquids, while totally maintaining the ionic liquid character. In this work, two mixtures of mutually miscible ionic liquids have been investigated, namely, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide + 1-ethyl-3-methylimidazolium ethylsulfate and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide + 1-butyl-3-ethylimidazolium ethylsulfate. Their ability to absorb carbon dioxide in the pressure range up to ca. 16 bar, at 298.2 K, was determined at different composition ratios of the mixtures; their thermal phase-transition temperatures and physical properties (density, viscosity, and surface tension) were determined over the entire compositional range, at atmospheric pressure and the same temperature. The absorption data were adequately correlated by the NRTL (Non-Random Two-Liquid) model, whereas different equations were successful in satisfactorily correlating the physical properties of the mixtures and in predicting them from knowledge of the properties of the pure ionic liquid components.

With a decrease in world oil reserves and a higher demand for petroleum and its derived products, the effective exploitation of oil reservoirs has become increasingly important. Enhanced oil recovery (EOR) assisted by surfactants is an effective method for recovering the oil from reservoirs that have lost their drive after the application of primary and secondary recovery methods. This research is aimed at showing the suitability of several ionic liquids as effective replacements for conventional surfactants in EOR. The reservoir fluid has been modelled as a ternary system of water (pure water or aqueous solution of NaCl) plus the ionic liquid trihexyl(tetradecyl)phosphonium chloride plus dodecane. Determination of its liquid-liquid phase equilibrium indicates the formation of a Winsor type III system, with a triphasic region and adjacent biphasic regions. The interfacial tensions in the system corroborate the ability of the ionic liquid to act as a surface active agent, as desirable for its use in an EOR process. A relevant transport property such as viscosity, in addition to density, has been experimentally measured for the equilibrium phases.

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Citrus essential oils have numerous applications in multiple sectors, including food, drink and personal care industries. Although mainly constituted by terpenes, the appealing characteristics of citrus essential oils are due to oxyterpenes and other derived oxygenated compounds. In fact, the presence of terpenes in the essential oil may lead to instability or loss of quality. Therefore, concentration of the oil in its oxyterpene compounds by removal of terpenes is desirable. The techniques currently in use for deterpenation of essential oils present a series of issues. In the search for better deterpenation processes, here the use of ionic liquids as solvents in liquid-liquid extraction is explored. In particular, the ionic liquids 1-ethyl-3-methylimidazolium acetate and 1-butyl-3-methylimidazolium acetate are investigated for their extraction of oxyterpene from a modelled citrus essential oil composed of limonene (terpene) and linalool (oxyterpene). The choice of the ionic liquids, in addition to other complementary characteristics, was based on a rationale of potential interactions that can be created preferentially with the linalool. The results show a great performance of these acetate-based ionic liquids, as compared to any other ionic or molecular solvent tested to date, for the concentration in oxyterpenes of the citrus essential oil.

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The object of the present work is to evaluate the possibility of carrying out the deterpenation of the citrus essential oil by using a mixture of ethanol and water as a solvent for liquid-liquid extraction. Liquid-liquid equilibrium has been determined for limonene + linalool + ethanol + water quaternary system at 298.15 K. Partitioning and selectivity of extraction were analyzed. Experimental data were correlated using the UNIQUAC and NRTL equations and the energetic parameters of these models at this temperature are determined.