Ionic liquid phase behaviour

Domariska, U. and Marciniak, A., Liquid phase behaviour of l-hexyloxy-3-methyl-imidazolium-based ionic liquids with hydrocarbons the influence of anion, /. Chem. Thermodyn., 31,57 2005. 

Once the force field is chosen, a proper simulation method needs to be selected. Molecular dynamics simulations are applied to determine the solvation behaviour of ionic liquids by means of solving the Newtonian equations of motion for all molecules in the presence of a gradient in potential energy. Ionic liquid phase equilibria are determined by using Monte Carlo simulations in the isothermal isobaric Gibbs ensemble, grand canonical ensemble or osmotic ensemble with clever sampling schemes. 

Holbrey, J. D. Seddon, K. R. The phase behaviour of l-alkyl-3-methylimidazolium tetrafluoroborates ionic liquids and ionic liquid crystals, J. Chem. Soc., Dalton Trans., 1999, 2133-2139. 

The behaviour of ternary systems consisting of two polymers and a solvent depends largely on the nature of interactions between components (1-4). Two types of limiting behaviour can be observed. The first one occurs in non-polar systems, where polymer-polymer interactions are very low. In such systems a liquid-liquid phase separation is usually observed each liquid phase contains almost the total quantity of one polymer species. The second type of behaviour often occurs in aqueous polymer solutions. The polar or ionic water-soluble polymers can interact to form macromolecular aggregates, occasionally insoluble, called "polymer complexes". Examples are polyanion-polycation couples stabilized through electrostatic interactions, or polyacid-polybase couples stabilized through hydrogen bonds. 

Domariska, U. and Marciniak A., Phase behaviour of l-hexyloxymethyl-3-methyl-imidazolium and 1,3-dihexyloxymethyl-imidazolium based ionic liquids with alcohols, water, ketones and hydrocarbons The effect of cation and anion on solubility. Fluid Phase Equilib., 260, 9, 2007. 

Lachwa, J. et al.. Condensed phase behaviour of ionic liquid-benzene mixtures congruent melting of a [emim][NTf2] C H inclusion crystal, Chem. Commun., 2445,2006. 

Polyakova, Y. and Row, K. H., Retention behaviour of N-CBZ-D-phenylalanine and D-tryptophan Effect of ionic liquid as mobile-phase modifier, Acta Chromatogr., 17, 210-221,2006. 

Rebelo LPN, Najdanovic-Visak V, Gomes de Azevedo R et al. (2005) Phase behaviour and thermodynamic properties of ionic liquids, ionic liquid mixtures, and ionic liquid solutions. In Rogers, RD, Seddon KR eds) Ionic liquids IIIA fundamentals, progress, challenges, and... 

Blanchard LA, Gu Z, Brennecke JF (2001) High-pressure phase behaviour of ionic liquids/ COj systems. J Phys Chem B 105 2437-2444... 

The immobilization method was also found to have influence on the membrane stability. A comparative study of the preparation of SILMs by two different methods, under pressure and vacuum were reported by Hemandez-Femandez et al. [26]. They used the ionic liquids, [bmim+][Cl"], [bmim ][BF ], [bmim ][PF "] and [bmim llNTf ] as liquid phase supported on a nylon membrane. Small losses of ionic liquid were observed after 7 days of operation when the ionic liquid was immobilized under pressure in a diffusion cell using n-hexane/n-hexane as surrounding phases. However, the losses of IL were higher when immobilization was carried out under vacuum, especially with the most viscous ionic liquids ([bmim+] [PF ] and [bmim+][CT]). This behaviour was explained by the fact that the higher viscosity of ILs makes difflcult their penetration into the middle of the deeper pores of the membrane, and therefore, the ionic liquid was mainly immobilized on the most external layer of the membrane, and consequently, the immobilized ionic liquid is more easily removed during operation. 

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