Thiodiphenol-Based <i>n</i>‑Dialkylamino Extractants for Selective Platinum Group Metal Separation from Automotive Catalysts

Five kinds of dialkylamino-modified thiodiphenols (<b>2</b>–<b>6</b>) were synthesized to elucidate the extraction of Pd­(II) and Pt­(IV) in HCl media by thiodiphenol-based <i>n</i>-dialkylamino extractants. Although the synthesized species <b>2</b>–<b>6</b> showed good solubility in hydrocarbon-based diluents such as kerosene, ShellSol D70, and ISOPAR M, the addition of <i>n</i>-octanol to the platinum group metals (PGMs) extraction was needed to inhibit third layer formation. All the <b>2</b>–<b>6</b> extract Pd­(II) and Pt­(IV) were much more effective than the commercial extractants, 2-hydroxy-5-nonylacetophenone oxime (LIX84-I), tri-<i>n</i>-butylphosphate (TBP), and tri-<i>n</i>-octylamine (TOA). Increasing the hydrophobicity of the extractants by increasing the alkyl chain length had an effect on the Pd­(II), Pt­(IV), and Rh­(III) extractabilities, which increased in the order from <b>2</b> to <b>6</b>. Extractant <b>6</b> could also be used for the selective extraction of Pd­(II) and Pt­(IV) (<i>E</i>% > 99%) from the leach liquors of automotive catalysts containing Pd­(II), Pt­(IV), Rh­(III), La­(III), Ce­(III), Y­(III), Zr­(IV), Ba­(II), and Al­(III) in HCl media. The effective stripping of Pd­(II) and Pt­(IV) was achieved from an extracted organic phase containing <b>6</b> using 0.5 M thiourea in 1.0 M HCl. In addition, <b>6</b> was reusable and exhibited a high <i>E</i>% for Pd­(II) and Pt­(IV) (>96%) after five extraction cycles, indicating potential usefulness for the selective recovery of Pd­(II) and Pt­(IV) from leachates in platinum group metal refineries

Thiodiphenol-Based <i>n</i>‑Dialkylamino Extractants for Selective Platinum Group Metal Separation from Automotive Catalysts

Five kinds of dialkylamino-modified thiodiphenols (<b>2</b>–<b>6</b>) were synthesized to elucidate the extraction of Pd­(II) and Pt­(IV) in HCl media by thiodiphenol-based <i>n</i>-dialkylamino extractants. Although the synthesized species <b>2</b>–<b>6</b> showed good solubility in hydrocarbon-based diluents such as kerosene, ShellSol D70, and ISOPAR M, the addition of <i>n</i>-octanol to the platinum group metals (PGMs) extraction was needed to inhibit third layer formation. All the <b>2</b>–<b>6</b> extract Pd­(II) and Pt­(IV) were much more effective than the commercial extractants, 2-hydroxy-5-nonylacetophenone oxime (LIX84-I), tri-<i>n</i>-butylphosphate (TBP), and tri-<i>n</i>-octylamine (TOA). Increasing the hydrophobicity of the extractants by increasing the alkyl chain length had an effect on the Pd­(II), Pt­(IV), and Rh­(III) extractabilities, which increased in the order from <b>2</b> to <b>6</b>. Extractant <b>6</b> could also be used for the selective extraction of Pd­(II) and Pt­(IV) (<i>E</i>% > 99%) from the leach liquors of automotive catalysts containing Pd­(II), Pt­(IV), Rh­(III), La­(III), Ce­(III), Y­(III), Zr­(IV), Ba­(II), and Al­(III) in HCl media. The effective stripping of Pd­(II) and Pt­(IV) was achieved from an extracted organic phase containing <b>6</b> using 0.5 M thiourea in 1.0 M HCl. In addition, <b>6</b> was reusable and exhibited a high <i>E</i>% for Pd­(II) and Pt­(IV) (>96%) after five extraction cycles, indicating potential usefulness for the selective recovery of Pd­(II) and Pt­(IV) from leachates in platinum group metal refineries

Phagocytosis assay using IgG-coated PE beads.

<p>Representative histograms of PE fluorescence in differentiated HL-60 cells without (red) and with (blue) TAP-4PH treatment. HL-60 cells in the absence of IgG-coated PE beads are shown in the black-dotted line.</p

Fluorescence imaging of live cells during neuronal differentiation of PC-12 cells.

<p>PC-12 cells were induced to differentiate into nerve cells by NGF. The cells at the indicated days after differentiation were treated with 50 μM TAP-4PH for 30 min. Top panels, TAP-4PH; bottom panels, bright-field images. Scale bar: 20 μm.</p

Chemical structure and fluorescence emission spectra of TAP-4PH.

<p>a) Chemical structure of the 1,3a,6a-Triazapentalene derivative TAP-4PH. b) Fluorescence emission spectra of TAP-4PH (10 μM) in aqueous and organic solvents. Green: acetonitrile; red: dichloromethane; blue: acetone; magenta: PBS.</p

Live cell visualization of cytoplasm by TAP-4PH in various cell types.

<p>Luminescence images of live cells treated with 10 μM TAP-4PH for 30 min at 37°C. Scale bar: 20 μm.</p

Time-dependent incorporation and distribution of TAP-4PH in A549 cells.

<p>a) Luminescence images of A549 cells incubated with 10 μM TAP-4PH for the indicated time periods. b) After incubation with 10 μM TAP-4PH for 30 min, the cells were washed and then incubated in fresh medium without TAP-4PH (time 0 min). Confocal luminescence images were taken after incubation for the indicated time periods. Scale bar: 20 μm.</p

Cell proliferation after treatment of A549 cells with TAP-4PH.

<p>Cell numbers were measured after treatment with TAP-4PH for 24 h. Data represent the mean ± SE, n = 3.</p