Vk. Manchanda et Pk. Mohapatra, 1-PHENYL-3-METHYL-4-BENZOYL-PYRAZOLONE-5 - A PROMISING EXTRACTANT FORPLUTONIUM, Separation science and technology, 29(8), 1994, pp. 1073-1086
Pyrazolones and isoxazolones have been found to be promising extractan
ts for metal ions, particularly from strong acidic media and in the pr
esence of complexing anions. Extraction constants (log k(ex)) in tolue
ne medium at 25-degrees-C for PuX4 species, where X = 1-phenyl-3-methy
l-4-acetyl-pyrazolone-5 (HPMAP), 1-phenyl-3-methyl-4-benzoyl-pyrazolon
e-5 (HPMBP), or phenyl-3-methyl-4-(3:5-dinitrobenzoyl)pyrazolone-5 (HP
MDP), are determined as 11.35 +/- 0.04, 12.89 +/- 0.03, and 12.73 +/-
0.02, respectively. These values are comparable to the corresponding v
alue for 3-phenyl-4-benzoyl-5-isoxazolone (HPBI) and several order of
magnitude larger than that for 2-thenoyltrifluoroacetone (HTTA). A sys
tematic study is carried out to investigate the extraction behavior of
these beta-diketones toward plutonium present in the analytical waste
solution obtained during the determination of uranium in a (U, Pu) fu
el sample by the Davies Gray method. Whereas 0.3 M HPMBP extracts >85%
of the plutonium present in a single step, maximum extraction observe
d with other reagents is much less than 0.1% HTTA, 0.3% HPMAP, and 2.5
% HPBI. The extraction of plutonium increases with different diluents
in the order n-dodecane < n-hexane < CHCl3 < CCl4 < toluene. Extracted
plutonium is quantitatively stripped with either 10 M HNO3 or 1:1 HCl
+ 0.1 M hydroquinone.