Effect of structural variation within lipophilic N-(X)sulfonyl carbamoyl lariat ethers on the selectivity and efficiency of competitive alkali metal cation extraction into chloroform.
Sixteen lipophilic N-(X)sulfonyl carbamoyl lariat ethers with polyether ring sizes of 12-crown-4, 14-crown-4, 15-crown-5, and 18-crown-6 are utilized for competitive alkali metal cation extractions from aqueous solutions into chloroform. Variation of the electron-withdrawing properties of X in the series of methyl, phenyl, 4-nitrophenyl, and trifluoromethyl allows the influence of the acidity of the C(O)NHSO2X group in the side arm upon extraction efficiency and selectivity to be assessed. With X = trifluoromethyl, effective alkali metal cation extractions from acidic, neutral, and basic aqueous solutions are achieved. When the crown ether rings are 14-crown-4, 15-crown-5, and 18-crown-6, selectivities for Li+, Na+, and K+, respectively, are observed. Results are compared with those reported for analogous lariat ether carboxylic acids and phosphonic acid monoethyl esters.
Lee
Eun Kyung
EK
Department of Chemistry and Biochemistry, Texas Tech University, Lubbock 79409-1061, USA.
Cho
Bong Rae
BR
Hu
Hui
H
Bartsch
Richard A
RA