Extraction of tetrachloroaurate or tetrabromoaurate anions has been carried out using several ionic liquids bearing trialkyl(2-ethoxy-2-oxoethyl)ammonium (alkyl group = C2H5 [EtGBOEt+], n-C3H7 [PrGBOEt+] or n-C4H9 [BuGBOEt+]) cations and halide (Cl− or Br−), bis(trifluoromethanesulfonyl)imide (Tf2N−) and dicyanamide (Dca−) anions. The removal of gold anionic moieties from water was first studied by mixing aqueous solutions containing gold complexes and water soluble bromide ionic liquids. This led to the formation of a solid precipitate corresponding to a hydrophobic ionic liquid based on a tetrahalogenoaurate anion. Liquid–liquid extraction of anionic gold complexes using hydrophobic ionic liquids was also investigated.
