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ACIDIC ESTERS OF ORTHOPHOSPHORIC ACID AS SELECTIVE EXTRACTANTS FOR METALLIC CATIONS, TRACER STUDIES

Journal Article · · J. Inorg. & Nuclear Chem.

The extraction of Sc(III), Y(III), La(III), Ac(III), Pm(III), Tm(III), and Am(III) into solutions of solvent from aqueous mineral acid phases have been investigated as a function of solvent concentrntion in the organic phase, hydrogen ion concentration in the aqueous phase, the nature of G, and the position of M(III) in the periodic table, using the radioactive-tracer technique. The distribution ratio, K, defined for a given radioactive nuclide as its concentration in the organic phase divided by its concentration in the aqueous phase, has been found, for all of the M(III) examples studied, to have an inverse third-power dependency upcn the hydrogen ion concentrntion in the aqueous phase in both the pendencies have been found to be direct first-power in the (GO)PO(OH)/ sub 2/ systems and direct (GO)/sub 2/PO(OH) systems. Since the (GO)/sub 2/PO(OH) solvents have been shown to be dimeric, the extracted species is postulated as M/ sup III/{HSTA(G0)/sub 2/P0/sub 2/!/sub 2/}/sub 3/. The (GO)PO(OH)/ sub 2/ solvents have been shown to be polymeric. A postulated dimer'' mechanism of extractlon suggests that the extracted species is M/sup III/ {HSTA(GO)PO/sub 3/H!/ sub 2/}/sub 3/. However, an alternative suggested infinite polymer'' mechanism of extraction seems equally likely. Specifically, solvents in which G is 2-ethyl hexyl, symbolized as EH, and para(1,1,3,3-tetramethyl butyl)phenyl, symbolized as O THETA , have been investigated. In both the (GO)PO(OH)/sub 2/ and (GO)/sub 2/ PO(OH) systems the O THETA solvent shows a higher K than the EH solvent. In the O THETA systems, the K/sub s/ (an empirical stability constant) for the di-ester is higher than that for the mono-ester for each of the members of the vertical group Sc, Y, La, Ac. In the EH systems, the K/sub s/ for the di-ester is the larger for Sc by a factor of approximately 30 and the smaller for Ac by a factor of approximately 1O-/sup -5. In all the systems the K (and K/sub s/) values are compressed toward the bottom of the group in the vertical group, Sc, Y, La, Ac, i.e., the ratio of the K (or Ks) of one element to that of the element lmmedlately below it decreases downward. (auth)

Research Organization:
Argonne National Lab., Lemont, Ill.
NSA Number:
NSA-13-002807
OSTI ID:
4312411
Journal Information:
J. Inorg. & Nuclear Chem., Journal Name: J. Inorg. & Nuclear Chem. Vol. Vol: 7
Country of Publication:
Country unknown/Code not available
Language:
English