Lariat ethers with a novel proton-ionizable group. Synthesis and solvent extraction of alkali metal cations

Abstract

Novel lariat ethers with pendent N-alkyl- and N-aryl-sulfonyl carbamoyl groups are synthesized in two steps from sym-(decyl)dibenzo-16-crown-5-oxyacetic acid; for competitive solvent extraction of alkali metal cations from aqueous solutions into chloroform by these proton-ionizable lariat ethers with ‘tunable’ acidity, the selectivity order is Na ⁺ >>K ⁺ with no detectable extraction of Li ⁺ , Rb ⁺ or Cs ⁺ .