Studies on synthesis and extraction behavior of Th(IV) and U(VI) of phosphoramidates

Phosphoramidates are new class of ligands derived from extremely popular phosphine oxide family and offers fascinating opportunities in various fields of chemistry. This field has the potential to develop and grow as the demand for these ligands continues to increase in the nuclear industry for the reprocessing and separation of nuclear waste. It seemed a constructive exercise to study the behavior of these compounds in the coordination spheres of some selected actinides, especially as these complexes possess potentially reactive P–N, ^~P–C–N and P–N–C linkages. Eventually, our search for newer ligands has lead us to investigate the extraction behavior of phosphoramidates towards the actinide ions having a amine group in the phosphonate moiety. The present study involves the synthesis, characterization, extraction of Th(IV) and U(VI) by dibutyl-N, N-diethyl phoshoramidate (DBDEP) and dioctylbutyl phosphoramidates (DOBP). DBDEP and DOBP were synthesized by Atherton–Todd reaction where the H-phosphonates has been reacted with the corresponding amine in presence of CCl₄ and Et3N. The purified product was characterized by various spectroscopic techniques, such as FT-IR, ¹H, ¹³C, and ³¹P NMR. Extraction study of Th(IV) and U(VI) is also performed by using 0.2 M solution of phosphoramidates in xylene at 303K. The distribution ratios of thorium and uranium were estimated and reported. (author)