C-pivot lariat ethers bearing an electron-donating side arm as lithium cation selective extractants

Abstract

A new series of methyl-substituted lariat ethers having a 12-, 13-, or 14-crown-4 ring was prepared by the reaction of the corresponding bromomethyl methyl crown ethers (1-3), with an appropriate sodium alkoxide or potassium phenoxide. Their complexation properties toward alkali metal cations were evaluated by the solvent extraction method. The lariat ether based on 13-crown-4 with a quinolinyloxy side arm (5a) shows a good affinity toward lithium cation over other alkali metal cations