- Metal catalysis in oxidation by peroxides. 24. Extraction of aqueous peroxomolybdenum species into organic media and their reactivity
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The effect of the lipophilicity and coordinating ability of neutral ligands, belonging to the classes of phosphoric amides and pyridine oxides, on the extraction of neutral oxidants molybdenum(VI)-peroxo complexes from an aqueous acidic phase to an organic one, has been studied.The nature of the Mo(VI)-peroxo species present both in aqueous and organic phase has also been investigated.Sizable amounts of mineral acid, added to adjust pH, may be extracted into the organic phase.The various factors affecting this process such as the nature of the acid added, the organic solvent and the neutral ligand, as well as the effect of this feature on the partition of the oxidant between the two phases are briefly discussed.
- Bortolini, Olga,Bragante, Letanzio,Di Furia, Fulvio,Modena, Giorgio
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- Synthesis, characterization and evaluation of phosphoramides for actinide extraction
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A new class of extractants called hexaalkylphosphoramides has been chosen for actinide separation applications in the present study. Hexaalkylphosphoramides [(NR2)3P[dbnd]O] are compounds which possess three nitrogen sub-units along with a strong donor oxygen atom. The studies on them provide an opportunity to synthesize a large variety of structurally diverse analogs. Thus, the desired properties of the extractant can be tuned for a specific application. We discuss the synthesis, purification, and characterization of two such hexaalkylphosphoramides (Propyl and Butyl) in this paper. Their physico-chemical properties were measured and the extraction behavior was evaluated with U(VI), Th(IV) and Pu(IV). The results were compared with trialkyl phosphates such as tri-n-butyl phosphate (TBP) and tri-n-amyl phosphate (TAP). The results revealed that the extraction behaviors of phosphoramides are comparable to trialkyl phosphates.
- Jegan,Suresh,Brahmmananda Rao,Sreenivasalu,Sivaraman
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- Rapid Analysis of Tetrakis(dialkylamino)phosphonium Stability in Alkaline Media
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Hydroxide-stable organic cations are crucial components for ion-transport processes in electrochemical energy systems, and the tetrakis(dialkylamino)phosphonium cation is a promising candidate for this application. These phosphoniums are known to be highly resistant to alkaline media; however, very few investigations have systematically evaluated how these cations decompose in the presence of hydroxide or alkoxide anions. The excellent stability of several tetraaminophosphoniums in 2 M KOH/CH3OH at 80 °C led us to design experiments for the rapid assessment of phosphonium degradation in homogeneous solution and under phase-transfer conditions. The analysis illustrated how substituents around the cation core affect both degradation pathways and rates. β-H elimination and direct attack at the phosphorus atom are the most common degradation pathways observed in an alcoholic solvent, while α-H abstraction and direct attack are observed under phase-transfer conditions (PhCl and 50 wt % NaOH/H2O). The collected data provided a relative stability comparison for this family of cations to enable future design improvements and illustrated the utility of using multiple tests for degradation studies.
- Womble, C. Tyler,Kang, Jamie,Hugar, Kristina M.,Coates, Geoffrey W.,Bernhard, Stefan,Noonan, Kevin J. T.
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p. 4038 - 4046
(2017/10/30)
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