New compound N-methyl-N-isopropyl octanthioamide for palladium selective extraction and separation from HCl media

To seek more efficient extractant for Pd recovery from leaching solution of spent automotive catalysts, a new compound N-methyl-N-isopropyl octanthioamide (TA-813) was synthesized and characterized through FT-IR, 1 H NMR, ESI-MS and elemental analysis. Its extraction and stripping behaviors for Pd were studied. To evaluate its reusability performance, extraction−stripping cycles were carried out. Finally, TA-813 was applied to separating Pd from simulated leaching solution of spent automotive catalysts. TA-813 shows fast extraction kinetics, high extraction efficiency and specific selectivity for Pd. During extraction two TA-813 molecules coordinate with one Pd. The loaded Pd in the organic phase is efficiently stripped by neutral and acidic thiourea solutions. TA-813 shows no loss in activity after eight extraction−stripping cycles. Even from simulated leaching solution of spent automotive catalysts, in which the concentrations of some purities (La, Ce, Mg, Al) are much higher than that of Pd, Pd is still selectively extracted.