Ekberg, Christian and Löfström-Engdahl, Elin and Aneheim, Emma and Foreman, Mark R. StJ. and Geist, Andreas and Lundberg, Daniel and Denecke, Melissa and Persson, Ingmar
(2015).
The structures of CyMe4-BTBP complexes of americium(III) and europium(III) in solvents used in solvent extraction, explaining their separation properties.
Dalton Transactions: an international journal of inorganic chemistry [incorporating Acta Chemica Scandinavica]. 44
:42
, 18395-18402
[Research article]
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PDF
- Accepted Version
1MB |
Official URL: http://dx.doi.org/10.1039/c5dt02859k
Abstract
Separation of trivalent actinoid (An(III)) and lanthanoid (Ln(III)) ions is extremely challenging due to their similar ionic radii and chemical properties. Poly-aromatic nitrogen compounds acting as tetradentate chelating ligands to the metal ions in the extraction, have the ability to sufficiently separate An(III) from Ln(III). One of these compounds, 6,6'-bis(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-benzol[1,2,4]triazin-3-yl)-[2,2]bipyridine, CyMe4-BTBP, has proven to be resistant towards acidic environments and strong radiation from radioactive decomposition. EXAFS studies of the dicomplexes of CyMe4-BTBP with americium(III) and europium(III) in nitrobenzene, cyclohexanone, 1-hexanol, 1-octanol and malonamide (DMDOHEMA) in 1-octanol have been carried out to get a deeper understanding of the parameters responsible for the separation. The predominating complexes independent of solvent used are [Am(CyMe4-BTBP)(2)(NO3)](2+) and [Eu(CyMe4-BTBP)(2)](3+), respectively, which are present as outer-sphere ion-pairs with nitrate ions in the studied solvents with low relative permittivity. The presence of a nitrate ion in the first coordination sphere of the americium(III) complex compensates the charge density of the complex considerably in comparison when only outer-sphere ion-pairs are formed as for the [Eu(CyMe4-BTBP)(2)](3+) complex. The stability and solubility of a complex in a solvent with low relative permittivity increase with decreasing charge density. The [Am(CyMe4-BTBP)(2)(NO3)](2+) complex will therefore be increasingly soluble and stabilized over the [Eu(CyMe4-BTBP)(2)](3+) complex in solvents with decreasing relative permittivity of the solvent. The separation of americium(III) from europium(III) with CyMe4-BTBP as extraction agent will increase with decreasing relative permittivity of the solvent, and thereby also with decreasing solubility of CyMe4-BTBP. The choice of solvent is therefore a balance of a high separation factor and sufficient solubility of the CyMe4-BTBP ligand.
Authors/Creators: | Ekberg, Christian and Löfström-Engdahl, Elin and Aneheim, Emma and Foreman, Mark R. StJ. and Geist, Andreas and Lundberg, Daniel and Denecke, Melissa and Persson, Ingmar | ||||||
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Title: | The structures of CyMe4-BTBP complexes of americium(III) and europium(III) in solvents used in solvent extraction, explaining their separation properties | ||||||
Series Name/Journal: | Dalton Transactions: an international journal of inorganic chemistry [incorporating Acta Chemica Scandinavica] | ||||||
Year of publishing : | 2015 | ||||||
Volume: | 44 | ||||||
Number: | 42 | ||||||
Page range: | 18395-18402 | ||||||
Number of Pages: | 8 | ||||||
Publisher: | Royal Society of Chemistry | ||||||
ISSN: | 1477-9226 | ||||||
Language: | English | ||||||
Publication Type: | Research article | ||||||
Refereed: | Yes | ||||||
Article category: | Scientific peer reviewed | ||||||
Version: | Accepted version | ||||||
Full Text Status: | Public | ||||||
Subjects: | (A) Swedish standard research categories 2011 > 1 Natural sciences > 104 Chemical Sciences > Inorganic Chemistry | ||||||
Agrovoc terms: | chemistry | ||||||
Keywords: | solvent extraction, americium, europium, structure determination, organic solvents | ||||||
URN:NBN: | urn:nbn:se:slu:epsilon-e-3476 | ||||||
Permanent URL: | http://urn.kb.se/resolve?urn=urn:nbn:se:slu:epsilon-e-3476 | ||||||
Additional ID: |
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ID Code: | 13338 | ||||||
Faculty: | NJ - Fakulteten för naturresurser och jordbruksvetenskap | ||||||
Department: | (NL, NJ) > Department of Chemistry and Biotechnology (140101-161231) | ||||||
External funders: | Knut and Alice Wallenberg Foundation | ||||||
Deposited By: | SLUpub Connector | ||||||
Deposited On: | 09 Jun 2016 11:47 | ||||||
Metadata Last Modified: | 09 Sep 2020 14:17 |
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