Synthesis and characterization of new kinds sulfoxide extractants for palladium(II)

Three new extractants for palladium(II) extraction: bis(noctyl-Sulfinyl-ethyl) ether(L-1), bis(isooctyl-Sulfinyl-ethyl)ether(L-2), bis(isooctyl-Sulfinyl-ethoxy)ethane(L-3) were synthesized. Micro-analytical data, elemental analysis, (HNMR)-H-1 and IR-spectra were used to confirm the structures. Based on independent extraction experiments of Pd(II), the extraction parameters of Pd(II) were studied in detail, and the optimal extraction parameters were obtained and summarized as the following: H+ concentration of aqueous phase 1.0-1.5 mol.L-1, sulfoxide extractants concentration 0.01-0.1 mol.L-1. The order of the extractability of the three extractants towards palladium(II) was L-2>L-3>L-1. The coordination number was studied by the slope method. The results indicated that, in low acidity, the coordination number for extracting palladium (II) was 1.0 with all three extractants, while it was 2.0 in high acidity. FT-IR spectra was used to analyze the structure of the complex. Palladium (II) was coordinated with the oxygen atom in S=O group of the three extractants. and palladium (II) may also coordinated with the oxygen atom in C-O-C group of extractant L-1, L-2.