In the reported experiments, crown ether-modified polyethylenimines (PEI-CR) were prepared to elucidate their cation binding efficiency and selectivity by liquid-liquid and solid-liquid extraction methods. With alkali metal cations it was found that polyethylenimines containing benzo-15-crown-5 moieties (Ia and Ib) extracted all cations examined more efficiently than their monomeric analogs, especially in the cases of K** plus and Rb** plus cations. The solid-liquid extraction revealed clearly that the polymers complexed with K** plus and Rb** plus cations according to a 1:2 cation-to-crown stoichiometry. The high selectivities of the polymers for K** plus and Rb** plus were interpreted in terms of the favorable conformation of the polymer chain for the formation of intramolecular 1:2 complexes. On the contrary, these polymers bound alkali earth cations less effectively with low selectivities.
|Number of pages||10|
|Journal||Journal of polymer science. Part A-1, Polymer chemistry|
|Publication status||Published - 1983 Jan 1|
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