New water-soluble calixarene-bis(benzocrown-6) for caesium-sodium separation by nanofiltration-complexation
Pellet-Rostaing, S Chitry, F Spitz, Jean-Alexis Sorin, A Favre-Reguillon, A Lemaire, M # ×
Pergamon-elsevier science ltd
Tetrahedron vol:59 issue:51 pages:10313-10324
Calix-bis(benzocrown-6) 6 and 7 were converted into the water-soluble receptors 9, 10, 12 and 15 by introducing hydroxy, carboxy, sulfato or diethanolamino groups at the para position of the phenolic ring and/or on the benzo-ether moieties. The complexation properties of these ionophores were studied for all alkali cations in methanolic and aqueous media. Stability constants were calculated by UV-Vis spectroscopy. All ligands showed a more or less affinity for the larger cations, depending on the nature and the position of the substituents grafted on the benzo-ether chain only or both on the calixarene ring and the benzo-ether loop. For selective Cs+/Na+ separation, the efficiency of the ligands was evaluated by means of a nanofiltration system. In comparison with the known tetrahydroxylated bis-crown-6 calixarene 1, compounds 9, 12 and 15 represent the most selective ligands for the Cs+ cation in a moderate salted medium ([NaNO3]=85 g/L). (C) 2003 Elsevier Ltd. All rights reserved.