SYNTHESIS AND ION-COMPLEXING PROPERTIES OF A NOVEL POLYMER-SUPPORTED REAGENT WITH DIPHOSPHONATE LIGANDS

A new chelating resin with diphosphonate groups has been synthesized f rom the tetraethyl ester of 1,1-vinylidenediphosphonic acid. Comonomer s such as acrylonitrile allow the sterically hindered monomer to be in corporated into the polymer network. A copolymer was prepared by suspe nsion polymerization in high yield with diphosphonate, acrylonitrile, and styrene in the monomer solution at a 4.5:1:3.1 weight ratio and 5 wt % divinylbenzene as the cross-link agent. Bifunctionality enhances metal ion complexation kinetics. The diphosphonate ligands are selecti ve chelators, while sulfonic acid ligands covalently bound to the phen yl groups enhance the accessibility of metal ions in the polymer matri x. The complexing ability of the polymer is studied with Eu(III) as th e target ion in 0.04-4.0 N HNO3 solutions in both the presence and abs ence of 0.40 N NaNO3. A sulfonic acid ion exchange resin complexes 14. 3% Eu(III) while the diphosphonate-based polymer complexes 96.5% from a 1 N HNO3/0.4 N NaNO3 solution.