Palladium(II) extraction from hydrochloric acid solutions with 2,6-bis[(methylsulfanyl)methyl]cyclohexan-1-one

Palladium(II) extraction from hydrochloric acid solutions with 2,6-bis[(methylsulfanyl)methyl]cyclohexan-1-one, obtained from natural methanethiol, was studied using chloroform as a diluent. Palladium(II) is recovered rapidly and with high efficiency by the extractant from solutions of 0.1–10 mol/L HCl and can be separated with high selectivity from Pt(IV), Cu(II), Ni(II), Zn(II) and Fe(III). A coordination mechanism of the palladium(II) extraction from 1 M HCl solutions was established. The extraction agent is coordinated to the Pd(II) ion through donor sulfur atoms in an extracted compound of the [PdCl2L] type. Stripping of Pd(II) is effectively carried out with a 1 M NH4OH solution or an acidic (0.1 mol/L HCl) thiourea solution.