Polymers with Multiple Ligand Sites for Metal Extractions in Dense-Phase Carbon Dioxide

• Published in: Industrial & engineering chemistry research Vol. 40; no. 5; pp. 1301 - 1305
• Main Authors: Powell, Kimberly R, McCleskey, T. Mark, Tumas, William, DeSimone, Joseph M
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 07.03.2001
• Subjects: Applied sciences; Exact sciences and technology; Organic polymers; Physicochemistry of polymers; Polymers with particular properties; Preparation, kinetics, thermodynamics, mechanism and catalysts; Fluorine containing copolymer; Phosphorus copolymer; Metal ion; Solution copolymerization; Liquid carbon dioxide; Organic phosphonate; Diketone; Experimental study; Lateral group; Binding capacity; Copper ion; Lanthanide ion; Europium ion; Preparation; Chelating agent; Soluble compound; Acrylate copolymer; Ion extraction
• DOI: 10.1021/ie000811b
• ISSN: 0888-5885

We have synthesized a series of CO2-soluble polymeric extractants with multiple ligand sites for CO2-based metal extractions. The CO2-soluble polymers were prepared via free-radical copolymerization of a fluorinated acrylate with a series of acrylate- or styrene-based monomers functionalized with ligand sites or ligand precursors. These polymers have high solubility in CO2; up to 30 wt % of a polymer with 15 mol % of a ligand-based monomer can be solubilized in liquid CO2 at 25 °C at 140 bar. Copper and europium extractions have been performed with β-diketone- and phosphonate-functionalized polymers, respectively. Preliminary extractions with copper nitrate were carried out at ligand-to-metal ratios of 1:1 and 2.7:1, resulting in 25−37% and 59% efficiency, respectively, suggesting a ligand binding stoichiometry of 2 for efficient extraction. Europium luminescence studies demonstrate that europium is bound to the polymer along with four water molecules in the inner coordination sphere.