Solvent Extraction of Alkali Metal and Alkaline Earth Metal Cations Using a Mono-Crown Ether and Bis-(Crown Ether)s

Mono-Crown Ether와 Bis-(Crown Ether)s를 이용한 알칼리금속과 알칼리토금속 양이온들의 용매추출

  • 신영국 (충북대학교 자연과학대학 화학과) ;
  • 김해중 (충북대학교 자연과학대학 화학과)
  • Received : 1996.10.08
  • Published : 1997.02.25

Abstract

Solvent extraction of alkali metal and alkaline earth metal cations by mono-crown ether(benzo-15-crown-5) and bis-(crown ether)s(ethylenediamine bis(4'-formyl benzo-15-crown-5)) containing benzo-15-crown-5 moieties were investigated with water-chloroform system at $25^{\circ}C$. The order of the extraction equilibrium constants($K_e$) and the complexation constants($K_c$) for the alkali metal and alkaline earth metal cations with mono-crown ether and bis-(crown ether)s were Ca(II)>Na(I)>Sr(II)>K(I)>Mg(II)>Rb(I) and Sr(II)>Ca(II)>K(I)>Rb(I)>Mg(II)>Na(I) respectively. These results were explained in terms of the size effect of metal cation and electron density effect. Also, the bis-(crown ether)s was found to extract metal cations more effectively than the corresponding mono-crown ether.

Keywords

solvent extraction;mono-crown ether;bis-(crown ether)s;extraction equilibrium constants($K_e$);complexation constants($K_c$)