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作 者:王登进[1] 王德枌[2] 孙小强[2] 胡宏纹[2]
机构地区:[1]中国药科大学 [2]南京大学化学系
出 处:《高等学校化学学报》1990年第7期672-675,共4页Chemical Journal of Chinese Universities
基 金:国家自然科学基金
摘 要:用两类结构不同的Schiff碱型、仲胺型双-(苯并-18-冠-6)在氯仿-水体系中对碱金属苦味酸盐进行萃取,测量了配合物组成比和萃取平衡常数。Extraction of alkali metal picrates with two different kinds of schiff base and secondary amine type bis-crown ethers containing benzo-18-crown-6 moiety was carried out in chloroform at 25 ±0. 2℃. The distribution ratio of alkali metal picrates, the stoichiometry and extraction equilibrium constantsK, of bis-crown ether-cation complexes were determined. The results show that the bis-crown ethers form1 : 1(crown unit : cation) cpmlexes with Na+,K+,Rb+ and probably form 2 : 1 intramolecular or intermolecuiar complexes -with Cs+, but mono Schiff base type bis-crown ethers preferably form 1 :1 complexes with Cs+. Moreover the K, values of the secondary amine type bis-crown ethers are much larger than those of the Schiff base type bis-crown ethers. N1 exhibits the greatest extractibility and selectivity for Cs+ ions. It is noteworthy that the bis-crown ethers N5 containing unsymmetrical crown rings has a larger extractibility for Rb+ ions.
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