Carboxyl-Functionalized Task-Specific Ionic Liquids for Solubilizing Metal Oxides
作者:Peter Nockemann、Ben Thijs、Tatjana N. Parac-Vogt、Kristof Van Hecke、Luc Van Meervelt、Bernard Tinant、Ingo Hartenbach、Thomas Schleid、Vu Thi Ngan、Minh Tho Nguyen、Koen Binnemans
DOI:10.1021/ic801213z
日期:2008.11.3
Imidazolium, pyridinium, pyrrolidinium, piperidinium, morpholinium, and quaternary ammonium bis(trifluoromethyl-sulfonyl)imide salts were functionalized with a carboxyl group. These ionic liquids are useful for the selective dissolution of metal oxides and hydroxides. Although these hydrophobic ionic liquids are immiscible with water at room temperature, several of them form a single phase with water at elevated temperatures. Phase separation occurs upon cooling. This thermomorphic behavior has been investigated by H-1 NMR, and it was found that it can be attributed to the temperature-dependent hydration and hydrogen-bond formation of the ionic liquid components. The crystal structures of four ionic liquids and five metal complexes have been determined.
Radiation Effect of Carboxyl-Functionalized Task-Specific Ionic Liquids on UO<sub>2</sub><sup>2+</sup> Removal: Experimental Study with DFT Validation
Experimental study with DFT validation on the effect of radiation on 1-carboxymethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([HOOCCH2MIM][NTf2]) as a solvent and extractant in rapid homogeneous extraction of UO22+ was performed for the first time. The radiolytic products of the anions and cations of [HOOCCH2MIM] [NTf2] were identified by F-19 NMR and high-resolution ESI-MS, respectively, and they were attributed to a decrease in UO22+ partitioning. Experimental study with DFT validation for complexing reactions between [HOOCCH2MIM] [NTf2] and radiolytic products proved that F- competition was one of the main reasons for the decrease in UO22+ partitioning. However, UO22+ partitioning in irradiated [HOOCCH2MIM] [NTf2] can largely be recovered after thorough water washing because of the removal of radiolytic products of [NTf2](-).