Conformationally Mobile Wide Rim Carbamoylmethylphosphine Oxide (CMPO)-Calixarenes

✍ Scribed by Susan E. Matthews; Mohamed Saadioui; Volker Böhmer; Silvia Barboso; Françoise Arnaud-Neu; Marie-José Schwing-Weill; Alejandro Garcia Carrera; Jean-François Dozol

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 157 KB
• Volume: 341
• Category: Article
• ISSN: 1615-4150
• DOI: 10.1002/(sici)1521-3897(199904)341:3<264::aid-prac264>3.0.co;2-f

✦ Synopsis

Nuclear waste reprocessing is a current topic of great importance. Presently plutonium and uranium are effectively removed from nuclear waste streams by the PUREX process [1]. This leaves a waste stream containing long lived radio-nuclides which are both β and γ emitters as well as α emitters. The latter class of compounds includes the actinides which, if efficiently removed, can be transmuted to non-radioactive or short lived nuclides.

Separation of lanthanides and actinides from nuclear waste is presently achieved using the TRUEX process [2] which utilises CMPO 1 (octyl phenyl N,N-diisobutyl carbamoylmethyl phosphine oxide) as the extractant. Although this is rather efficient it shows little discrimination between lanthanides and actinides. We have previously shown that the attachment of four CMPO-like moieties to the wide rim of a calix [4]arene not only greatly enhances extraction [3], but also imparts a selectivity for actinides and lighter lanthanides [4]. This increase in extraction for molecules of type 2 is believed to be due to the co-operative action of the ligating functions, since studies on CMPO 1 have shown three ligands to be required per cation [5]. However, to date the actual composition and conformation of the extracted species are unknown [6].