Metal ion separations with proton-ionizable crown ethers and their polymers

Richard A. Bartsch, Takashi Hayashita, Joung Hae Lee, Jong Seung Kim, Matthew G. Hankins

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)


Lipophilic crown ethers with pendent proton-ionizable groups are novel complexing agents for use in metal ion separations by solvent extraction. For a series of structurally related, lipophilic dibenzocrown ether carboxylic acids, the efficiency and selectivity of competitive alkali metal cation extraction for aqueous solution into chloroform is found to be strongly influenced by the crown ether ring size and the lipophilic group attachment site. Reaction of dibenzocrown ether carboxylic acids with formaldehyde in formic acid produces condensation polymers which possess both ion-exchange and cyclic polyether binding sites for metal ion complexation. These resins exhibit excellent exchange kinetics for competitive alkali metal cation sorption from aqueous solution and subsequent stripping and may be used in concentrator columns for the recovery of these metal ions from very dilute aqueous solution. Cation selectivity in the sorption and stripping steps is controlled by the structure of the crown ether monomer unit.

Original languageEnglish
Pages (from-to)305-311
Number of pages7
JournalSupramolecular Chemistry
Issue number3-4
Publication statusPublished - 1993
Externally publishedYes

Bibliographical note

Funding Information:
This research was supported by the Division of Chemical Sciences of the Office of Basic Energy Science of the U.S. Department of Energy (Grant DE-FGO5-88ER13832) and the Texas Higher Education Co-ordinating Board Advanced Technology Program. JHL received a postdoctoral fellowship from the Korea Science and Engineering Foundation.

ASJC Scopus subject areas

  • General Chemistry


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