Synthesis of novel bifunctional polymers for selective metal ion complexation

Polymer supported reagents were synthesized by functionalization of polymer supports for the purpose of selective metal ion separation. Three categories of polymer supports with different microenvironments were prepared. Vinylbenzyl chloride (VBC) crosslinked with 2% divinylbenzene was copolymerized with either methyl methacrylate (MMA) to give a polar environment or styrene (STY) to give a hydrophobic environment. Different oligo ethyleneimines and phosphonic acid were used as ligands in the synthesis of monofunctional resins. Bifunctional aminophosphonic acid resins were prepared by phosphorylation of ethyleneimine ligands. The characterization of the resins shows that as the length of the ethyleneimine ligand increases, more crosslinking takes place. Metal ion studies of Cu²⁺, Pb²⁺, Cd²⁺ and Eu³⁺ were performed in pH 5 sodium-acetate buffer solution at a 24 hour contact time. The microenvironmental effect plays an important role in the degree of functionalization as well as in metal ion complexation. Bifunctional aminophosphonic acid resins outperformed the amine or phosphonic acid monofunctional resins in metal ion complexation. The Mannich reaction of a polystyrene-based primary amine resin with diethylmalonate(DEM), tetraisopropylmethylene diphosphonate (TIPP), triethylphosphonoacetate (TEPAc) and phosphorous acid (PhA) were carried out varying the acid amount, reaction time and temperature. The Fries rearrangement of poly(4-acetoxystyrene) was successfully achieved with aluminum chloride-nitrobenzene under moisture-free reaction conditions. The Fries-rearranged resin and its phosphorylated analogue were studied with several metal ions.