Abstract
Lipophilic crown ethers with pendant proton-ionizable groups are novel complexing agents for use in solvent extraction of alkali metal and alkaline earth cations. A variety of crown carboxylic acids, crown phosphonic acid monoesters, and crown phosphonic acids have been synthesized to probe the effect of structural variation within the complexing agent upon selectivity and efficiency in solvent extraction. Synthetic routes to these novel extractants and results from competitive solvent extractions of alkali metal cations and of alkaline earth cations from aqueous solutions into chloroform are summarized