Influence of extractant structure on extraction of nitric acid and americium(III) with diaryl (dialkyl)[diethylcarbamoylmethyl]phosphine oxides

Journal Article · Fri Sep 01 04:00:00 EDT 1995 · Radiochemistry

OSTI ID:175700

Chmutova, M K; Ivanova, L A; Kochetkova, N E ^[1]

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1. Vernadskii Institute of Geochemistry and Analytical Chemistry, Moscow (Russian Federation); and others

A study has been made of nitric acid and americium(III) extraction with dichlorethane solutions of dialkl-(diaryl)[diethylcarbamoylmethyl]phosphine oxides containing various substituents (alkyl, aryl, alkoxyl, and mixed-ligand) at the phosphorus atom. Nitric acid is extracted as complexes containing one, two, or three acid molecules per molecule of the reagent. The effective constants of the nitric acid extraction by all the reagents ({bar K}{sub ex}{sup HNO3}) have been evaluated. The {bar K}{sub ex}{sup HNO3} values linearly correlate with the ligand basicity (pK{sub a}). All the reagents americium(III) complexes with two molecules of reagent. The effective constants of americium(III) extraction {bar K}{sub ex}{sup Am} have been evaluated; no general correlation between {bar K} {sub ex}{sup Am} and pK{sub a} has been found. However, the following partial linear dependences between {bar K}{sub ex}{sup Am} and pK{sub a} have been determined: the direct dependence ({bar K} increases with increasing pK{sub a}) in the case of successive groups by phenyl groups, which illustrates the {open_quotes}anomalous aryl strengthening,{close_quotes} and the direct dependence in the case of introduction of substituents in benzene rings bonded to the phosphorus atom. It has been found that in the case of reagent containing tert-butyl radicals at phosphorus, {bar K}{sub ex}{sup HNO3} and {bar K}{sub ex}{sup Am} fall out of the linear dependences, probably owing to the prevalence of steric factor in the complex formation.

• OSTI ID: 175700
• Journal Information: Radiochemistry, Journal Name: Radiochemistry Journal Issue: 5 Vol. 37; ISSN RDIOEO; ISSN 1066-3622
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
40 CHEMISTRY
AMERICIUM
EXTRACTION
MOLECULAR STRUCTURE
NITRIC ACID
PHOSPHINE OXIDES