- Synthesis and characterization of nitrogen-based ionic liquids bearing allyl groups and examples of their application
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The syntheses and full spectral (NMR, MS, and IR), thermal (DSC) and ion chromatographic characterization of two series of amine-derived ionic liquids bearing allyl substituents and having chloride or bis(trifluoromethanesulfonyl)amide anions have been presented. The analysis of the dependence of the 1H NMR chemical shift values of the selected protons on the cation and anion structure has been conducted. DSC analysis records together with ion chromatography analysis results have been presented and interpreted. Moreover, a selection of obtained chloride ionic liquids have been transformed into the corresponding chlorocobaltates and chlorozincates or used as substrates in thiol-ene click reactions to indicate their potential as precursors of catalysts or various surface modifiers.
- Zajac, Adrian,Szpecht, Andrea,Szymanska, Anna,Zielinski, Dawid,Stolarska, Olga,Smiglak, Marcin,Maciejewski, Hieronim
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p. 12274 - 12288
(2020/07/30)
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- Ultrafast Ligand Self-Exchanging Gadolinium Complexes in Ionic Liquids for NMR Field Probes
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Concurrent magnetic field monitoring in MRI with an array of NMR field probes allows for reducing image imperfections. High 19F concentrations together with short relaxation times are basic probe properties. We present the NMR properties of [Gd
- Looser, Anna,Barmet, Christoph,Fox, Thomas,Blacque, Olivier,Gross, Simon,Nussbaum, Jennifer,Pruessmann, Klaas P.,Alberto, Roger
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supporting information
p. 2314 - 2319
(2018/02/23)
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- Dimethyldioxirane (DMDO) as a valuable oxidant for the synthesis of polyfunctional aromatic imidazolium monomers bearing epoxides
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Conventional organic salts represent a new paradigm in many areas of research. Despite their great potential, an improvement in their physicochemical properties requires the chemical modification of their intrinsic structure. Thus, an efficient pathway was developed for the preparation of polyfunctional imidazolium monomers incorporating aromatic rings and terminal epoxides which presented a real synthetic challenge. In this work, we describe the reactivity of various oxidizing agents to develop a strong, clean and powerful methodology to generate epoxidized salts. Various reaction conditions for the formation of the epoxides were investigated such as the role of the cation and the counterion as well as the influence of an aromatic and/or aliphatic linker chain. Finally, we have evaluated the thermal properties of these new polyfunctional salts by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC).
- Chardin,Rouden,Livi,Baudoux
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supporting information
p. 5054 - 5059
(2017/11/09)
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- Anion Analysis of Ionic Liquids and Ionic Liquid Purity Assessment by Ion Chromatography
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The simultaneous determination of halide impurities (fluoride, chloride, bromide, and iodide) and ionic liquid (IL) anions (tetrafluoroborate, hexafluorophosphate, and triflimide) using ion chromatography was developed with a basic, non-gradient ion chromatography system. The non-gradient method uses the eluent Na2CO3/NaHCO3in water/acetonitrile (70:30 v:v) on the AS 22 column to enable a rapid and simultaneous analysis of different IL and halide anions within an acceptable run-time (22 min) and with good resolution R of larger than 2.4, a capacity k′ between 0.4 and 5.1, selectivities α between 1.3 and 2.1, and peak asymmetries Asof less than 1.5. Halide impurities below 1 ppm (1 mg·L–1of prepared sample solution) could be quantified. A range of ionic liquids with tetrafluoroborate [BF4]–, hexafluorophosphate [PF6]–, and bis(trifluoromethylsulfonyl)imide (triflimide) [NTf2]–anions combined with cations based on imidazole, pyridine, and tetrahydrothiophene could be analyzed for their anion purity. The IL-cations do not influence the chromatographic results. With the analysis of 18 ILs differing in their cation-anion combination we could prove the general applicability of the described method for the anion purity analysis of ionic liquids with respect to halide ions. The IL-anion purity of most ILs was above 98 wt %. The highest IL-anion purity was 99.8 wt %, implying anion impurities of only 0.2 wt %. The used halide anion from the synthesis route was the major anion impurity, yet with chloride also bromide and fluoride (potentially from hydrolysis of [BF4]–) were often detected. When iodide was used, at least chloride but sometimes also bromide and fluoride was present. However, even if the IL-anion content is above 99 wt %, it does not necessarily indicate an ionic liquid devoid of other impurities. From the IC analysis, one can also deduce a possible cation impurity if one takes into account the expected (calculated) IL-anion content. A matching experimental and theoretical IL-anion content excludes, a higher experimental content indicates the presence of residual KBF4, NH4PF6, or LiNTf2salt from the halide to IL-anion exchange.
- Rutz, Christina,Schmolke, Laura,Gvilava, Vasily,Janiak, Christoph
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supporting information
p. 130 - 135
(2017/02/05)
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- Bifunctional hydrophobic ionic liquids: Facile synthesis by thiol-ene "click" chemistry
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We describe the facile, robust and orthogonal fabrication of a structurally comprehensive library of hydrophobic trimethoxysilyl-functionalized ionic liquids with C7-C15 thioether spacer, using thiol-ene "click" chemistry. The synthesized ionic liquids displayed very low glass transition temperatures, high thermal stability and were hydrophobic in character. And the ability to serve as surface coating agents was tested by immobilizing them on the surface of iron oxide supermagnetic nanoparticles and the organic loadings were quantified.
- Sanchez Zayas, Manuel,Gaitor, Jamie C.,Nestor, Stephen T.,Minkowicz, Samuel,Sheng, Yinghong,Mirjafari, Arsalan
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p. 2443 - 2452
(2016/05/19)
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- Size matters! on the way to ionic liquid systems without ion pairing
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Several, partly new, ionic liquids (ILs) containing imidazolium and ammonium cations as well as the medium-sized [NTf2]- (0.230 nm3; Tf=CF3SO3-) and the large [Al(hfip)4]- (0.581 nm3; hfip=OC(H)(CF3)2) anions were synthesized and characterized. Their temperature-dependent viscosities and conductivities between 25 and 80°C showed typical Vogel-Fulcher-Tammann (VFT) behavior. Ion-specific self-diffusion constants were measured at room temperature by pulsed-gradient stimulated-echo (PGSTE) NMR experiments. In general, self-diffusion constants of both cations and anions in [Al(hfip) 4]--based ILs were higher than in [NTf2] --based ILs. Ionicities were calculated from self-diffusion constants and measured bulk conductivities, and showed that [Al(hfip)4] --based ILs yield higher ionicities than their [NTf2] - analogues, the former of which reach values of virtually 100% in some cases.From these observations it was concluded that [Al(hfip) 4]--based ILs come close to systems without any interactions, and this hypothesis is underlined with a Hirshfeld analysis. Additionally, a robust, modified Marcus theory quantitatively accounted for the differences between the two anions and yielded a minimum of the activation energy for ion movement at an anion diameter of slightly greater than 1 nm, which fits almost perfectly the size of [Al(hfip)4]-. Shallow Coulomb potential wells are responsible for the high mobility of ILs with such anions. Looking for ideally non-associated ionic liquids (ILs)? By performing extensive NMR diffusion, viscosity, and conductivity measurements as well as applying a modified Marcus theory to a large set of ionic liquids (ILs), it was shown that the ideal noninteracting IL anion should have an optimum diameter of 1 nm and a fluorinated surface. Several of the here described [Al(hfip)4]- (hfip=OC(H)(CF3)2) ILs fulfill these criteria. Shallow Coulomb potential wells (see figure) are responsible for the high mobility of ILs with such anions.
- Rupp, Alexander,Roznyatovskaya, Nataliya,Scherer, Harald,Beichel, Witali,Klose, Petra,Sturm, Carola,Hoffmann, Anke,Tuebke, Jens,Koslowski, Thorsten,Krossing, Ingo
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supporting information
p. 9794 - 9804
(2014/08/18)
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- Isoamyl acetate synthesis in imidazolium-based ionic liquids using packed bed enzyme microreactor
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The acylation of isoamyl alcohol with acetic anhydride catalyzed by immobilized Candida antarctica lipase B was studied in ionic liquids (ILs) based on quaternary imidazolium cations with alkyl, alkenyl, alkynyl, benzyl, alkoxyl or N-aminopropyl side chains. Among the tested ILs, the highest enzyme activity together with the highest isoamyl acetate yield were obtained in [C 7mmim][Tf2N]. No loss of lipase B activity was observed during one-month incubation in this hydrophobic IL without the presence of substrates. Isoamyl acetate synthesis using [C7mmim][Tf2N] as solvent was further studied in a continuously operated miniaturized enzymatic packed bed reactor at various flow rates and temperatures. Up to 92% isoamyl acetate yield could be obtained within 15 min by using 0.5 M acetic anhydride and 1.5 M isoamyl alcohol inlet concentrations at 55°C, corresponding to the volumetric productivity of 61 mmol l-1 min -1, which to the best of our knowledge is the highest reported so far for this reaction. No decrease in productivity was experienced during the subsequent runs of continuous microbioreactor operation performed within 14 consecutive days. The benefits of reactor miniaturization along with the green solvent application were therefore successfully exploited for the development of a sustainable flavour ester production.
- Cvjetko, Marina,Vorkapi?-Fura?, Jasna,?nidar?i?-Plazl, Polona
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experimental part
p. 1344 - 1350
(2012/09/08)
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