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-CH₂CONEt₂ (1) and TC[6]A-CH₂SCOCH₃ (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.