Selective extraction of metals from mixed oxide matrixes using choline-based ionic liquids.

The solubility of a range of metal oxides in a eutectic mixture of urea/choline chloride is quantified, and it is shown that the dissolved metals can be reclaimed from a mixed metal oxide matrix using electrodeposition.

Ionic liquid analogues formed from hydrated metal salts.

A dark green, viscous liquid can be formed by mixing choline chloride with chromium(III) chloride hexahydrate and the physical properties are characteristic of an ionic liquid. The eutectic composition is found to be 1:2 choline chloride/chromium chloride. The viscosity and conductivity are measured as a function of temperature and composition and explained in terms of the ion size and liquid void volume.

Deep eutectic solvents formed between choline chloride and carboxylic acids: versatile alternatives to ionic liquids.

Deep Eutectic Solvents (DES) can be formed between a variety of quaternary ammonium salts and carboxylic acids. The physical properties are significantly affected by the structure of the carboxylic acid but the phase behavior of the mixtures can be simply modeled by taking account of the mole fraction of carboxylic acid in the mixture. The physical properties such as viscosity, conductivity, and surface tension of these DES are similar to ambient temperature ionic liquids and insight into the cause of these properties is gained using hole-theory.

Novel solvent properties of choline chloride/urea mixtures.

Eutectic mixtures of urea and a range of quaternary ammonium salts are liquid at ambient temperatures and have interesting solvent properties.