Extraction of Pd(ii) and Pt(ii) from aqueous hydrochloric acid with 1,3-diaminocalix[4]arene: switching of the extraction selectivity by using different extraction modes

Abstract

1,3-Diaminocalix[4]arene shows extraction ability toward Pd(ii) and Pt(ii), the selectivity of which can be switched by changing the concentrations of H+ and Cl− in the aqueous phase.

New reagents for selective extraction of Pd(ii) and Au(iii) from acidic media

“…Analysis of high-field 1 H and 13 C NMR spectra of the products demonstrate that sets of proton and carbon chemical shifts and proton-proton and carbon-proton spin-spin couplings for each compound are similar to those of the previously reported structurally relative bis(a-amine oximes). 41,42 The chemical purity of the compounds (96-99%) was assessed by 1 H NMR from the carbon-13 satellite signals.…”

“…Nuclear magnetic resonance (NMR) spectra were recorded at 27-30 1C for solutions (c 10-40 mg mL À1 ) on a Bruker AV 300 and a Bruker DRX-500 spectrometer (300. 13 Signal assignment was made using J modulated 13 C NMR spectra (proton-noise-decoupling, the opposite phases for the signals of the atoms with the odd and even numbers of the attached protons, tuning to the constant J = 135 Hz). The signals of N-H and O-H groups were determined by polarization transfer upon saturation of the HDO signal of the water traces in the solvent used.…”

“…The signals of N-H and O-H groups were determined by polarization transfer upon saturation of the HDO signal of the water traces in the solvent used. Carbon-proton spin-spin coupling constants were taken from proton-coupled 13 C NMR spectra. The sign of spin-spin couplings was not determined.…”

“…Hydrometallurgical processes produce acidic leachates during the recovery of noble metals from waste sources, while the selective recovery of Au, Pd, or Pt from this kind of matrix is quite challenging. 8–13…”

“…7 Hydrometallurgical processes produce acidic leachates during the recovery of noble metals from waste sources, while the selective recovery of Au, Pd, or Pt from this kind of matrix is quite challenging. [8][9][10][11][12][13] Beside traditional liquid-liquid extraction, selective extraction of noble metals is carried out using a variety of approaches using ion exchange resins, 14 ionic liquids, [15][16][17][18] nanocomposites, 19 silica-based adsorbent functionalized with macrocyclic ligands, 20 and a combination of solvent extraction and precipitation methods, 21 or solvent extraction and direct electrodeposition from the loaded organic phase. 22 In general, the extraction behaviour of Pt(IV) and Pd(II) by most of the commercial amines and solvating extractants is similar, which is an incentive for the development of new reagents for the selective extraction of palladium.…”