이온성 크라운에테르 포스포닉산에 의한 알칼리 금속 양이온과 알칼리 토금속 양이온의 용매추출

초록

A comparison of alkali metal cation and alkaline earth cation solvent extraction was made for three additional monoionizable crown ethers and one diionizable crown ether. sym-(n-Octyldibenzo)-16-crown-5-oxyacetic acid 1 exhibited high efficiency and selecvity in solvent extraction of alkali metal cations with respect to that observed with alkaline earth cations. Sizes of Na+ and Ca2+ appropriately match with the cavity size of monoethyl sym-bis[4(5)-tert-butylbenzo]-16-crown-5-oxymethylphosphonic acid 3. As the result, Na+ and Ca2+are the best extracted. sym-(n-Octyldibenzo)-16-crown-5- oxymethyldiphosphonic acid 4 was found to be somewhat selective for Na+ over Li+ and other alkaline earth metal cations. In the complexation of alklaine earth cations by crown ether diphosphonic acid 4, Ca2+ and Sr2+ are the appropriate sizes, but lager Ba2+may be due to favorable formation of a sandwich type complex between the crown ether cavity and the dianion of the deprotonated crown ether phoaphonic acid moiety.

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