크라운에테르 포스포닉산 모노에틸 에스테르에 의한 알칼리 토금속 양이온의 경쟁 용매추출

Competitive Solvent Extractions of Alkaline Earth Metal Cations by Crown Ether Phosphonic Acid Monoethyl Esters

Competitive solvent extraction of alkaline earth metal cations from water into organic solvent containing the carboxylic acid crown ether and analogous crown ether phosphonic acid monoethyl esters were investigated. sym-(n-Decyldibenzo)-16-crown-5xyacetic acid underline{1} and monoethyl sym-(n-decyldibenzo)-16-crown-5-oxymethylphosphonic acid underline{3} are structurally identical except for the ionizable groups. Both of them provide similar extraction behavior in terms of efficiency and selectivity, but monoethyl sym-(n-decyldibenzo)-16-crown-5-oxymethylphosphonic acid underline3 showed higher alkaline earth metals loadings at acidic or neutral media. Monoethylsym-(n-octyldibenzo)-16-rown-5-oxymethylphosphonic acid underline{2} showed better selectivity and alkaline earth metals loading than did the analogous sym-(n-octyldibenzo)-16-crown-5-oxymethyldiphosphonic acid underline{6}.