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Synthesis of polymer-supported azacrown ether ion exchanger, {(4,5): (13,14)-dibenzo-6,9,12-trioxa-3,15,21-triazazabicyclo[15.3.1]heneicosa-1(21),17,19-triene-2,16-dione : DBPDA ion exchanger}, and its ion binding ability to alkali metal (Li+, Na+, K+) picrates were studied. The binding constants (Kb) of DBPDA ion exchanger to the alkali metal picrates in ether type solvents were obtained by spectrophotometry. Binding constants of alkali metal ions were in the order to Li < Na < K, and alkali metal ions were formed 1 : 1 complexes with ligands of DBPDA ion exchanger. Also, Kb was found to depend on the variables such as solvent and temperature. The binding constants for the complexes were obtained in the ranges of 2 × 103 ∼ 4 × 104 M-1. In order to obtain the enthalpy (△H) and entropy changes (△S) in the complexation process, Kb were plotted against the temperature in the ranges of 10∼40℃ according to the van't Hoff theory. Enthalphy and entropy changes were found in the ranges of -2.71∼-3.79 kcal/mol, and -16.52∼-20.57 eu, respectively.
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