Extraction of metals in carbon dioxide and chelating agents therefor
AssigneeUniversity of Pittsburgh
InventorsEric J. Beckman, Alan J. Russell
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Abstract
The present invention provides a chelating agent suitable for chelating metals metals in liquid or supercritical carbon dioxide. The chelating agent comprises generally a conventional chelating group and a CO.sub.2 -soluble functional group covalently attached to the chelating group. Examples of suitable CO.sub.2 -soluble functional groups include fluorinated polyether groups, silicone groups, fluorinated polyalkyl groups, phosphazene groups and fluorinated polyacrylate groups. The present invention also provides a method of extracting a metal from a matrix containing at least one other material and the metal using such CO.sub.2 -soluble chelating agents.
Claims8
A chelating agent suitable for forming coordinated complexes with a metal in liquid and supercritcal carbon dioxide of covalently bonded (i) a bispicolylamino group, (ii) a non-electron withdrawing spacer group selected (CH.sub.2).sub.x and (iii) a CO.sub.2 soluble functional group selected from (CF.sub.2 CF.sub.2 O).sub.x (CF.sub.2 O).sub.x and (CF.sub.2 (CF.sub.3)FO).sub.x, wherein x is selected to be .gtoreq.3 and is selected to minimize the electron withdrawing effect of the CO.sub.2 soluble functional group and to achieve a chelating agent solubility of at least a 10.sup.-3 gram/gram CO.sub.2.
Dependencies are inferred from the claim text.