• Journal of the Korean Applied Science and Technology
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• v.22 no.3
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• pp.219-227
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• 2005

Competitive solvent extraction of the mixure of alkali metal and alkaline earth cation from water into organic solvent containing the crown ether carboxylic acid and anlogous crown ether phosphonic acid was investigated as follows. The lipophilic group is found to strongly influence to the selective extraction in the mixed systems from only alkali metal cation for sym-(n-decyldibenzo)-16-crown-5-oxyacetic acid $\underline{1}$ to mostly alkaline earth metal cation for sym-bis[4(5)-tert-butylbenzo]-16-crown-5-oxyacetic acid $\underline{3}$. Monoethyl sym-(n-decyldibenzo)-16-crown-5-oxymethylphosphonic acid $\underline{2}$. and monoethyl-sym- bis]4(5)-tert-butylbenzo]-16-crown-5-oxymethylphosphonic acid $\underline{4}$ showed good selectivity for $Na^+$ over $Mg^{2+}$, the second extracted ion. Structural variation in the crown ether phosphonic acid somewhat was influenced to the extraction selectivity in the mixed systems. when variation of the ionized group is influenced in the mixed systems, the selectivity of $Na^+$ as the second extracted ion was much better crown ether carboxylic acid $\underline{1}$ than crown ether phosphonic acid $\underline{2}$, while the efficiency of $Na^+$ extraction was better $\underline{2}$ (83% total loading) than $\underline{1}$ (32%).

• Journal of the Korean Applied Science and Technology
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• v.22 no.1
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• pp.9-14
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• 2005

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 $\underline{3}$ 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 $\underline{6}$.

• Journal of the Korean Applied Science and Technology
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• v.22 no.1
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• pp.50-55
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• 2005

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 $\underline{1}$ 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 $Ca^{2+}$ appropriately match with the cavity size of monoethyl sym-bis[4(5)-tert-butylbenzo]-16-crown-5-oxymethylphosphonic acid $\underline{3}$. As the result, $Na^+$ and $Ca^{2+}$ are the best extracted. sym-(n-Octyldibenzo)-16-crown-5-oxymethyldiphosphonic acid $\underline{4}$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 $\underline{4}$, $Ca^{2+}$ and $Sr^{2+}$ are the appropriate sizes, but lager $Ba^{2+}$ 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.

• Applied Biological Chemistry
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• v.40 no.5
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• pp.442-446
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• 1997

A new analytical method was developed by HPLC after supercritical fluid extraction and fluorogenic derivatization for the determination of quinclorac (3,7-dichloro-8-quinoline carboxylic acid) in soil. The graminicide quinclorac was extracted from soil by supercritical fluid extraction. Supercritical carbon dioxide at 7000 psi $(80^{\circ}C)$ modified with 30% of methanol extracted quinclorac from soil samples at the level of $0.1ng\;g^{-1}$ with 96% recovery. Extracted quinclorac was determined by HPLC as a fluorescent derivative. Derivatization was made with 4-bromomethyl-7-methoxycoumarin (4-Br-Mmc) using 18-crown-6-ether as a catalyst. The conversion was completed within 30 min and the limit of detection was 0.5 ppb to prove that the procedure could be used in the residue analysis of the pesticides containing carboxylic acid group.

• Applied Chemistry for Engineering
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• v.3 no.2
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• pp.266-272
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• 1992

Azacrownoalkyl phenylphosphinic acids were synthesized and their competitive solvent extraction characteristics from water to chloroform layer were investigated. Phosphinic acids were synthesized in good yields by one step reaction of phenylphosphinate, aldehyde, and monoazacrown ether and then basic hydrolysis of the resulting phosphinate dsters. These complexing agents revealed a wide effective pH range in extraction of alkali metal ions from water to the organic phase and total metal ion loading at pH 11 was about 75%. The selectivity of the cation extraction was determined mainly by the cavity size of the azacrown ethers, showing $Na^+$ >> $K^+$ > $Rb^+$ > $Li^+$ > $Cs^+$ for the alkyl phenylphosphinic acid ${\underline{2}}$, containing monoaza-15-crown-5 and $K^+$ >> $Rb^+$ > $Na^+$ > $Cs^+$ > $Li^+$ for the alkyl phenylphosphinic acid, ${\underline{3}}$, containing monoaza-18-crown-6 moiety. Applicable pH range of these azacrown ether phosphinic acids in solvent extraction of alkali metal cations was wider than a crownether carboxylic acid with similar selectivity, showing considerable amount of metal ion loading in slightly acidic or neutral media.