Synergism in the Solvent Extraction of Europium(III) with Thenoyltrifluoroacetone and CMPO in Methylimidazolium Ionic Liquids

摘要

The solvent extraction of Eu(III) from an aqueous chloride phase into hydrophobic ionic liquids (ILs), 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imides ([C(1)C(n)im(+)][Tf2N-], n=4, 6, 8 and 10), by -diketone 2-thenoyltrifluoroacetone (HTTA) alone and in combination with N,N-diisobutyl-2-(octylphenylphosphoryl)acetamide (CMPO) was investigated. The interaction between the two extractants (acidic/neutral) in deuterochloroform has been studied by H-1, C-13, F-19 and P-31 NMR spectra and NOESY experiments. H-1 and F-19 Q-NMR analytical techniques were also applied for determination of [C(1)C(4)im(+)] and [Tf2N-] entities transferred into the aqueous phase. Eu(III) was efficiently extracted by HTTA/[C(1)C(n)im(+)][Tf2N-] and HTTA/CMPO/[C(1)C(n)im(+)][Tf2N-] systems but a relatively small synergism was established. A cation extraction mechanism was proposed via the log-log slope analysis method. The effect of the IL cation alkyl chain length on the extraction process was studied as well.