Selective Extraction Ability of Thiacalix[6]arene Derivatives from Rare Metal Mixed Solution

Abstract

In this study, a synthesis and extraction capability of two new thiacalix [6]arene (TC[6]A) derivatives modified at the lower or upper rims, which are TC[6]A-CH 2 CONEt 2 (1) and TC[6]A-CH 2 SCOCH 3 (2), respectively, will be discussed. The metal extraction properties of 1, 2, and TC[6]A (3), from automotive catalyst residue solution containing platinum-group metal cations (PGM solution) have been investigated. Compound 3 shows highest extraction capability for Zr cation which is ca. 87% (in pH 4.0 PGM solution). On the other hand, 1 shows the highest extraction capability for Zr cation which is ca. 63% (in pH 3.0 of PGM solution), 2 shows the highest extractability for Pd cation which is ca. 86% (in pH 1.5 of PGM solution) and second highest one for Zr cation which is ca. 57% (in pH 4.0 of PGM solution) respectively.

Synthesis and characterisation of p-diethylaminomethylthiacalix[4]arene for selective recovery of platinum from automotive catalyst residue

“…Compounds p-tert-butylthiacalix [4]arene (2), p-tertbutylthiacalix [6]arene (3), p-tert-butyl-tetrakis[(dimethyl (thiocarbamoyl))oxy]thiacalix [4]arene (4) and p-tert-butylhexakis[(methylcarboxyl)oxy]thiacalix [6]arene (5) were synthesised according to literature methods (5,(32)(33)(34). As shown in Scheme 3, the synthesis of p-diethylaminomethylthiacalix [4]arene 1 proceeds as follows.…”

“…Many functionalised thiacalix[n]arenes have been used for solvent extraction of alkali and transition metals (5, 6, 12 -20). Recently, we reported the synthesis and extraction capability of new, modified thiacalix [6]arene derivatives, in which the lower or upper rim was modified with a ZCH 2 CONEt 2 group or a ZCH 2 SCOCH 3 group, respectively (6). The extraction of Pt(IV), Pd(II) and Rh (III) ions from a spent automotive catalyst residue solution containing PGMs was very high using thiacalix [6]arene-CH 2 SCOCH 3 .…”

“…Recently, we reported the synthesis and extraction capability of new, modified thiacalix [6]arene derivatives, in which the lower or upper rim was modified with a ZCH 2 CONEt 2 group or a ZCH 2 SCOCH 3 group, respectively (6). The extraction of Pt(IV), Pd(II) and Rh (III) ions from a spent automotive catalyst residue solution containing PGMs was very high using thiacalix [6]arene-CH 2 SCOCH 3 . According to the literature, thiacalix[n]arene and its derivatives have very high Pd (II) ion extraction percentages, but the efficiency of Pt (IV) extraction is typically less than 5% (18,19).…”

“…To date, the separation of PGMs is carried out using commercially available extractants. Although it is well known that these extracting reagents can extract precious metals from waste solutions, examples of selective separation of particular metal ions from various precious metals are scarce (5,6). Therefore, novel reagents, which can effectively separate rare metals, are required.…”

Selective extraction of Pd(II) ions from automotive catalyst residue in Cl− media by O-thiocarbamoyl-functionalized thiacalix[n]arenes

“…Traeger et al (2012a,b) developed many acyclic sulfur-based extractants and explained their advantages over commercial extractants (Traeger et al, 2012a,b). On the other hand, thiacalix[n]arenes (n = 4, 6, and 8), are macrocyclic compounds, have high affinities for alkali, transition, and lanthanide metal ions, and are used for PGM separation (Itoh et al, 2010;Rajiv Gandhi et al, 2014;. In our previous work, we have reported that 5,11,17,23,29,35-tert-butyl-37,38,39,40,41,42-(dimethylthiocarbamoyl)oxy thiacalix[6]arene (1), 5,11,17,23-tert-butyl-25,26,27,28-(dimethylthiocarbamoyl)oxy thiacalix[4]arene (2), and p-tert-butylthiacalix[4/6]arenes (3 and 4) extract very high amounts of Pd(II) ions in a pH range of 3-4 from single-metal solutions and from diluted solutions of acidic leached automotive catalyst residues (Rajiv .…”