Radiation stability of diglycolamide functionalized calix[4]arenes in ionic liquid: Solvent extraction, EPR and GC-MS studies

Ionic liquid-based solvent systems containing diglycolamide-functionalized calix[4]arenes (C4DGAs) are efficient for actinide ion extraction from nitric acid feeds. Therefore, the radiolytic stability of three C4DGAs (wide-rim, narrow-rim and both side DGA-functionalized calix[4]arenes) and TODGA (N,N,N',N'-tetraoctyldiglycolamide) (used for comparison purpose), was evaluated by exposing their solutions in an ionic liquid as well as a 95:5 mixture of n-dodecane + isodecanol to gamma radiation up to an absorbed dose of 1000 kGy. Liquid-liquid extraction studies were carried out using Am-241 as a radiotracer. Apart from a decrease in the D-Am values, ascribed to radiolytic degradation, FT-IR, EPR and GC-MS studies were carried out to characterize the degraded species. The different extractants are less sensitive to radiolytic degradation in the ionic liquid than in the molecular diluent. (c) 2016 Elsevier B.V. All rights reserved.