Palladium(II) Extraction from Hydrochloric Acid Solutions with 4-[(Hexylsulfanyl)methyl]-3, 5-Dimethyl-1H-Pyrazole

Palladium(II) extraction from hydrochloric acid solutions with a novel weakly basic complexing reagent, 4-[(hexylsulfanyl)methyl]-3,5-dimethyl-1H-pyrazole, dissolved in chloroform was studied. Palladium(II) was found to be highly efficiently extracted from 0.1-3 mol/L HC1 solutions. A coordination mechanism of palladium(II) extraction with a protonated form of the reagent via fast interphase transfer of ion associates was proposed. The composition of the extracted compound, [PdCl2 mu-L](n) (n > 2), was found, and the way of coordination of the reagent to metal ions through N(2) nitrogen atom and thioether sulfur atom was determined. The reagent can be recommended for concentrating palladium(II) and selectively separating it from platinum(IV), copper(II), nickel(II), and iron(III).