Dissolution behavior of precious metals and selective palladium leaching from spent automotive catalysts by trihalide ionic liquids.

The dissolution behavior of the precious metals gold, platinum, rhodium and palladium in the trihexyl(tetradecyl)phosphonium trihalide ionic liquids [P][Cl], [P][Br], [P][IBr] and [P][I] was investigated. The highest dissolution rates were observed for the trichloride ionic liquid [P][Cl] and this system was investigated in more detail. The effects of the trichloride concentration in the ionic liquid and temperature were studied, reaching higher leaching rates at higher trichloride conversions and increased temperatures.

Thermal stability of trihexyl(tetradecyl)phosphonium chloride.

Dynamic TGA studies of phosphonium ionic liquids have reported thermal stabilities of 300 °C or higher for these compounds. This is often an overestimation of the real thermal stability. The chosen technique as well as the experimental parameters can influence the thermal stability.

Ionic liquids with trichloride anions for oxidative dissolution of metals and alloys.

Ionic liquids (ILs) with trichloride anions ([Cl]) combined with different cations were synthesised by bringing chlorine gas into contact with the corresponding chloride (Cl) ILs at room temperature. These trichloride ILs safely store chlorine and are useful as oxidising agents for dissolution of various metals and alloys under mild conditions.

Metal extraction with a short-chain imidazolium nitrate ionic liquid.

A short-chain symmetrical dihexyl imidazolium nitrate ionic liquid for conventional solvent extraction of metals was developed. Rare earths were found to be preferentially extracted over 1st row transition metals leading to the application of the ionic liquid system for separation of the Sm(iii)/Co(ii) and La(iii)/Ni(ii) pairs, which are relevant for the recycling of SmCo magnets and NiMH batteries.