T. Hayashita, K. Yamasaki, K. Kunogi
Mar 1, 1996
Citations
0
Influential Citations
10
Citations
Journal
Supramolecular Chemistry
Abstract
Abstract 2,2′-[1,2-Ethanediylbis(oxy)]bisbenzoic acid (1), 2,2′-[oxybis(1,2-ethanediyloxy)]bisbenzoic acid (2), 1,2-[2′-(acetoxy)phenoxy] ethane (3), and 1,5-[2′-(acetoxy)phenoxy]-3-oxopentane (4) have been prepared for use in selective Pb(II) separation. The extraction of Pb(II) and Cu(II) from buffered aqueous solutions of varying pH into chloroform by 1–4 is examined in relation to their molecular structure. Compound 1 with an ethylene glycol spacer unit exhibits excellent extraction selectivity for Pb(II) over Cu(II). Lengthening the spacer group to a diethylene glycol unit diminishes the extraction efficiency and selectivity. For 3 and 4, extraction was inefficient due to low lipophilicity and solubility of the ligands in chloroform. Condensation polymerization of compounds 3 and 4 with formaldehyde in formic acid provides stable chelating resins 5 and 6 which contain both ion-exchange and polyether binding sites for metal complexation. Resin 5 with an ethylene glycol spacer group is found to be an e...