Synthesis of <i>N</i>-polyethereal polypyrroles and their application for the preconcentration of rare earth ions

Abstract

Conducting polymers containing polyether pseudocages (PI, PII, PIII) have been synthesized via chemical oxidation of 1,5-bis(1,1-pyrrole)-3-oxabutane (MI), 1,8-bis(I,I-pyrrole)-3,6-dioxahexane (MII), and 1,11-bis(1,1-pyrrole)-3,6,9-trioxaundecane (MIII) using anhydrous FeCl3 in CHCl3. Because as obtained polymer resins did not give any response toward any cations, they were reduced (undoped) using chemical reducing agents. Tetrabutylammonium hydroxide was found to be more effective in undoping to obtain more reproducible and reusable polymer resins. The undoped polymer resins were tried in the extraction of rare earth metal ions from the aqueous medium. Among them, only PIII resin removes La(III), Eu(III) and Yb(III) and can be employed for the preconcentration of these metal ions. For batch extraction of La(III), Eu(III) and Yb(III) at neutral pH values, percent recoveries of 98.0 +/- 1.0, 90.7 +/- 1.4, 87.3 +/- 4.0, respectively, has been obtained. The sorption capacity is found as 1.3 mg of La(III) per gram of PIII resin. The PIII resin could be reused at least five times without significant change in its sorption capacity. (c) 2008 Wiley Periodicals, Inc.