Calixcrown oligomers as cation carriers in a bulk liquid membrane

摘要

One monomeric calixcrown(1) and four calixcrown oligomers(2-5) were used as carriers in a bulk liquid membrane. All the carriers transported K~+ selectively, the order of the transport rate being: the calixcrown amide oligomer 4>the calixcrown ether oligomer 2>the calixcrown ester oligomer 3>the calixcrown siloxane oligomer 5, and the K~+/Na~+ selectivity decreased in the reverse order. These results demonstrate that the transport rate and the selectivity of calixcrown oligomers are related to the type of second component linking the calcixcrown unit. In two-cation transport experiments, at high[K~+]/[Na~+] ratios, all the carriers transported K~+ over Na~+.