Synergic solvent extraction and thermal studies of fluorinated beta-diketone-organophosphorus adduct complexes of lanthanide and related elements
- Iowa State Univ., Ames, IA (United States)
Solvent extraction and gas chromatography have proven to be very successful techniques for quantitative separation and determination of many types of compounds. While the former has been well established as a universal tool for both organic and inorganic separations, the latter has been primarily used for organic applications. Recent investigations (80) however, have amply demonstrated the utility of gas chromatography for inorganic analysis. Although both techniqes provide excellent analytical capabilities, a greater analytical potential for separation and determination of inorganic materials would be produced by a combination of the two techniques. The combination of the resoltion capabilites of gas chromatography and the specificity of solvent extraction should considerably broaden the scope of practical analysis of cationic mixtures. During a recent study at the Ames Laboratory a mixture of hexafluoracetylacetone (HHFA) and tri-n-butylphosphate (TBP) in cyclohexane was used for the first time as a gas chromatographic reagent for the lanthanide elements (19). This initial work included a broad spectrum of studies designed to assess the potential of mixed-ligand chelates for inorganic gas chromatography. The successful gas chromatography (GC) R.E.(A) 3 -2TBP, where A is the anion of the ligand and R.E. represents the rare earth cation, were extracted into the organic phase. The synergic system, HHFA-TBP, was found to possess extraction properties necessary for a subsequent gas chromatographic determination. Rare earths at micro and macro levels (10-8 to 10-2 _M_) were rapidly and quantitatively converted to the corresponding mixed chelates under pH conditions such that hydrolysis of the cations in the aqueous phase did not occur. The stioichiometry of the complexes extracted into solutions of HHFA-TBP in cyclohexane remained constant for the lanthanide series. Analytical extraction curves were measured for Th(IV), Sc(III), U(VI), U(IV), Ca(II), Y(III), FE(III), Zn(II), CU(II) and some lanthanide elements. The utility of the extraction systems, HTFA in benzene, HTFA-TBP in cyclohexane and HHFA-TBP in cyclohexane, for analytical separations of SC(III), FE(III), UOx -2 and TH(IV) from the rare earths and of the rare earths from Al(III) was demonstrated. A literature review containing the available information on the extraction of various cations by HTFA is given. On the basis of this information and the reported distribution curves, conditions for the separation of certain cations from each other and from the reare earths were suggested. Trends in thermal stability and volatility of chelates of the lanthanide and releated elements were obtained from thermogravimetric anlaysis of the hydrated and mixed chelates. Significant improvements in thermal stability of rare earth chelates were obtained by displacement of hydrated water upon adduct formation with TBP.
- Research Organization:
- Ames Lab., Ames, IA (United States)
- Sponsoring Organization:
- US Atomic Energy Commission (AEC)
- DOE Contract Number:
- W-7405-ENG-82.
- NSA Number:
- NSA-24-036350
- OSTI ID:
- 4911085
- Report Number(s):
- IS-T-353
- Resource Relation:
- Other Information: Thesis. UNCL
- Country of Publication:
- United States
- Language:
- English
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BIOCHEMISTRY
BUTYL PHOSPHATES
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ETHYL RADICALS
HEPTANE
KETONES
METALS
METHYL RADICALS
OCTANE
ORGANIC FLUORINE COMPOUNDS
PENTANE
PHOSPHORIC ACID
PROPYL RADICALS
SEPARATION PROCESSES
SOLUTIONS
SYNERGISM
WATER IRON
GALLIUM
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INDIUM
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HOLMIUM
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LUTETIUM
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THULIUM
THORIUM
CALCIUM
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N20500* -Chemistry-Separation Processes