T. Hayashita, H. Sawano, T. Higuchi
Jan 8, 1999
Citations
0
Influential Citations
31
Citations
Journal
Analytical Chemistry
Abstract
1,2-Bis[2-(2‘-carboxyalkyloxy)phenoxy]ethanes (3−6), 1,2-bis[2-(2‘-carboxyheptyloxy)phenoxy]benzene (7), 1,2-bis[2-(2‘-carboxyheptyloxy)ethoxy]benzene (8), and 1,2-bis[2-(2‘-carboxyheptyloxy)ethoxy]ethane (9), which possess pseudo-18-crown-6 frameworks, are synthesized for use in selective Pb(II) extraction. For comparison, monocarboxylic acid analogues of 2-phenoxyoctanoic acid (1) and 2-(2‘-methoxyphenyloxy)octanoic acid (2) are also prepared. Extraction of Pb(II) and Cu(II) from buffered aqueous solutions of varying pH into chloroform by these ligands is examined in relation to their molecular structure. Polyether dicarboxylic acids 3−9 exhibit higher Pb(II)/Cu(II) selectivities than the monocarboxylic acids 1 and 2. The alkyl chain length variation from hexyl to octyl to dodecyl to hexadecyl does not affect the Pb(II)/Cu(II) selectivity. Due to steric stress of the binding site, tribenzo ligand 7 shows a low Pb(II)/Cu(II) selectivity. For 3, 8, and 9, no significant difference in Pb(II)/Cu(II) selecti...