Abstract
The distribution of Tc (VII) between aqueous acidic solutions and organic solutions of nitrogen-containing extractants is investigated in order to establish the relationships between extraction power towards the Tc (VII) -anion, ligand molecular structure, influence of the media and the speciation in this ion-pair extraction. Ligands belonging to the class of calixarenes, derivatized with pyridino groups were newly devloped for these purposes. The number of substituents per calixarene, the position of the nitrogen and the size of calixarene are varying structural parameters. The nitrogen atoms are either protonated or quaternized to allow ion-pair extraction. The aqueous phase contains nitrate or chloride at varying or constant ionic strength. Experiments using Aliquat-336 were conductedunder similar conditions.
