Actinides separation using calyx[n]arenes as extractor agents

This work deals with the synthesis and characterization of the n-acetatescalyx[n]arenes (n= 4, 6 and 8), that they were obtained by acetylation reaction of p-terc-butyl-calix[n]arenes (n= 4, 6 and 8), with acetic anhydride, to be used as extractor agents in the separation of the uranyl ion, UO22+. The n-acetatescalix[n]arenes (n= 4, 6 and 8), were obtained in excess of acetic anhydride, under heating and after the removal of the solvent they are in the powder form. After their synthesis, these were treated with chloroform/methanol for get products with appropriate degree of purity. Qualitative tests of solubility in acetone, chloroform, MIBK, showed that as expected, these compounds have difficult dissolution. The proposed molecular formulate, they were based in the percents of C and H analysis: C52H64O8, C78H96O12 and C104H128O16 for the n-acetatescalyx[n]arenes (n= 4, 6 and 8) respectively. These compounds were characterized also through infrared absorption spectroscopy, ultraviolet absorption spectroscopy and nuclear magnetic resonance of protons spectroscopy. For the extraction studies, parameters such as, the influence of the pH in the extraction of UO22+, the extraction kinetics, the phases relationship, the diluent, the extractor agent concentration, the use of an chelating ligand (HTTA), the size of the cavity of the extractor agent and its functionalization, the saline effect and the reversion of UO22+ were investigated. The results showed that the cavity with uranophilic properties, hexaacetatecalix[n]arene, associated to the chelating ligand, HTTA, is a quite promising system in the extraction of the uranium. (author)