The Synthesis of Li+-selective Polyether Carriers and Thier Behavior in Cation Transport through Liquid Membranes

Abstract Noncyclic polyethers exhibiting lithium ion selectivity have been synthesized. Their competitive alkalimetal-ion transport through liquid membranes has been investigated, and the influence of their structures on the rates and selectivities of cation transport has been demonstrated. It has been found that the introduction of the oxytrimethylene chain on the polyethers is significant for the appearance of a high selectivity for the lithium ion, and also that the kind of terminal group might play an important role either in determining the rates of cation transport or the selectivity for the lithium ion. The introduction of a methyl group at the 2-position on the quinolyl terminal group of the polyether increased largely the selectivity for the lithium ion compared with that of the polyether having an unsubstituted quinolyl group. The cause of this was discussed on the basis of the NMR spectroscopic method and the CPK-model building.