Synthesis of proton-ionizable lariat ethers

Proton-ionizable lariat ethers are used for solvent extraction by binding metal cations within their central cavities and by their side arms. In this research, three species of proton-ionizable lariat ethers have been prepared to study the effects of structural modifications upon the selectivity and efficiency of metal ion separations.

The first series is a group of N-(trifluoromethyl) ulfonyl sym-(l-alkynyl)dibenzol6-crown-5-oxyacetamides and their carboxylic acid precursors with geminal 1-alkynyl groups of differing lengths for the solvent extraction of alkali metal cations and their transport across polymeric inclusion membranes.

The second series is a family of lariat ether carboxylic acids and N-(X)sulfonyl carboxamides with X = methyl and trifluoromethyl and differing ring sizes for use in the separation of Co(II) and Zn(II) by metal ion flotation. The crown ether ring sizes vary from 13-crown-4 to 19-crown-6.

The third series is a group of new lipophilic proton-ionizable lariat ethers with differing ring sizes for the solvent extraction of alkali metal cations. The lipophilic lariat ethers have crown ether rings of sizes varying from 12-crown-4 to 18-crown-6. The lariat ether NT(X)-sulfonyl carboxamides contain four different X groups to "tune" the acidity of the pendant acidic function.