Electrospray ionization mass spectrometry of ionic liquids and determination of their solubility in water

Electrospray ionization mass spectrometry is used to detect both the cations (C⁺) and the anions (A^–) of ionic liquids (CA). In this study, the ionic liquids are diluted with aqueous methanol before injection. In addition to the main peaks of the parent ions, fragmentation products are observed upon increasing the cone voltage, whereas aggregates of the parent ion with one or more ionic liquid molecules (e.g., C(CA)_n⁺, A(CA)_n^–) are observed upon decreasing the cone voltage. The ions of several ionic liquids in a mixture are also detected and the ratios of their concentrations estimated. A method is developed to determine quantitatively the concentration of an ionic liquid in solution by using the cation and anion of another ionic liquid as internal standards. By using this method, the solubilities in water at room temperature (22±1 °C) of three typical hydrophobic ionic liquids have been determined: 0.70±0.08 g L^–1 for methyltributylammonium bis(trifluoromethylsulfonyl)imide (MeBu₃NNTf₂), 6.0±0.5 g L^–1 for butylmethylpyrrolidinium bis(trifluoromethylsulfonyl)imide (BuMePyrNTf₂), and 18.6±0.7 g L^–1 for 1-butyl-3-methylimidazolium hexafluorophosphate (BMIPF₆).     

Mercury extraction by ionic liquids: temperature and alkyl chain length effect

The preliminary results described here show the complete transfer of Hg(II) ions, in the absence of a chelating agent in 1-alkyl-3-methylimidazolium hexafluorophosphate ionic liquids; the lag time required to gain the quantitative metal ion partition turned out to be strongly dependent both on alkyl chain length on the imidazolium ring and on the working temperature.     

Ce0.8Y0.2O1.9-Ca3(PO4)2-K3PO4复合电解质在中温区的质子导电性及在常压合成氨中的应用

A precursor of Ce_0.8Y_0.2O_1.9(YDC) solid electrolyte was synthesized by the gol-gel method. YDC and phosphates powders were prepared by mixing the YDC and phosphates according to different weight ratios. The mixtures of the YDC and binary phosphates were ground and sintered at 1 400 ℃. The proton conductivity in solid electrolyte of the sintered samples was examined using electrochemical methods at 400～800 ℃. Ammonia was synthesized from nitrogen and hydrogen at atmospheric pressure in the solid state proton conducting cell reactor. The optimal condition for the ammonia production was determined. The result indicated that composite electrolyte of 80wt% YDC: 20wt% binary phosphates as proton conductor could obtain the highest ionic conductivity and ammonia production rate among the four samples, the rate of evolution of ammonia was up to 9.5 × 10^-9 mol·s^-1·cm^-2.     

Metathesis of hex-1-ene in ionic liquids catalyzed by WCl6

Metathesis of hex-1-ene in ionic liquids catalyzed by WCl₆ was studied. The metathesis is preceded by isomerization of hex-1-ene to hex-2-ene, from which the main reaction product, viz., oct-4-ene, is derived. The WCl₆-1-butyl-3-methylimidazolium tetrafluoroborate (BMIM·BF₄) system efficiently catalyzes metathesis of linear olefin, the ionic liquid serving as the reaction medium by forming a stable homogeneous catalytic system with WCl₆. The yields of the metathesis products increase with increasing reaction temperature. The addition of tin-containing promoters leads to a substantial increase in the reaction rate. In the WCl₆-BMIM·BF₄-SnBu₄ system, the selectivity of the formation of oct-4-ene is significantly enhanced.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2094–2097, October, 2004.     

Regioselective acylation of methyl 2-methyl-4H-thieno[3,2-b]pyrrole-5-carboxylate

The influence of catalysts, acid chlorides, and solvents on the acylation of methyl 2-methyl-4H-thieno[3,2-b]pyrrole-5-carboxylate was studied. The use of AlCl₃ allows the regioselective introduction of the acyl group into position 3 to be performed, whereas the acyl group is regioselectively introduced into position 6 of thienopyrrole when SnCl₄ is used.     

Polypyrrole-Fe2O3 nanohybrid materials for electrochemical storage

We report on the synthesis and electrochemical characterization of nanohybrid polypyrrole (PPy) (PPy/Fe₂O₃) materials for electrochemical storage applications. We have shown that the incorporation of nanoparticles inside the PPy notably increases the charge storage capability in comparison to the “pure” conducting polymer. Incorporation of large anions, i.e., paratoluenesulfonate, allows a further improvement in the capacity. These charge storage modifications have been attributed to the morphology of the composite in which the particle sizes and the specific surface area are modified with the incorporation of nanoparticles. High capacity and stability have been obtained in PC/NEt₄BF₄ (at 20 mV/s), i.e., 47 mAh/g, with only a 3% charge loss after one thousand cyles. The kinetics of charge–discharge is also improved by the hybrid nanocomposite morphology modifications, which increase the rate of insertion–expulsion of counter anions in the bulk of the film. A room temperature ionic liquid such as imidazolium trifluoromethanesulfonimide seems to be a promising electrolyte because it further increases the capacity up to 53 mAh/g with a high stability during charge–discharge processes.     

Liquid Densities and Excess Molar Volumes for Binary Systems (Ionic Liquids + Methanol or Water) at 298.15, 303.15 and 313.15 K,and at Atmospheric Pressure

Binary excess molar volumes, V _m ^E, have been evaluated from density measurements, using a vibrating tube densimeter over the entire composition range for binary liquid mixtures of ionic liquids 1-ethyl-3-methyl-imidazolium diethyleneglycol monomethylethersulphate [EMIM]⁺[CH₃(OCH₂CH₂)₂OSO₃]⁻ or 1-butyl-3-methyl-imidazolium diethyleneglycol monomethylethersulphate [BMIM]⁺[CH₃(OCH₂CH₂)₂OSO₃]⁻ or 1-methyl-3-octyl-imidazolium diethyleneglycol monomethylethersulphate [MOIM]⁺[CH₃(OCH₂CH₂)₂OSO₃]⁻+methanol and [EMIM]⁺[CH₃(OCH₂CH₂)₂OSO₃]⁻+water at 298.15, 303.15 and 313.15 K. The V _m ^E values were found to be negative for all systems studied. The V _m ^E results are explained in terms of intermolecular interactions and packing effects. The experimental data were fitted by the Redlich-Kister polynomial.     

Electrophysical properties of titanates of alkaline-earth metals

Results on oxygen-ion, electron, and proton conduction and oxygen penetrability of titanates of alkaline-earth metals doped with acceptor admixtures are briefly reviewed. The applicability of these materials in electrochemical devices, in particular, as oxygen-penetrable membranes, is considered. The focus is on the studies carried out at the Institute of High-Temperature Electrochemistry, Ural Branch, Russian Academy of Sciences.     

基于离子液体的炭材料制备、改性及应用

离子液体因其熔点低、液态温域宽、蒸气压低、热稳定性高、电导率高、电化学窗口宽、结构可设计及对许多化合物的亲和性等系列性能而引起人们广泛关注。离子液体在炭材料制备、改性领域展示出了良好的前景及巨大的应用潜力,可直接作为碳源,经过高温炭化实现杂原子掺杂制备多孔炭材料;离子液体也可充当反应介质和致孔剂,将生物质转化为多孔炭材料;此外,由于离子液体与炭材料相容性较好,可以用于多孔炭材料改性制备炭复合材料。基于离子液体的炭材料在电催化、超级电容器、吸附分离及生物医学等领域具有潜在的应用价值。本文总结了基于离子液体炭材料的制备、改性及应用最新研究进展,并着重介绍了其在能源和环境相关领域的应用。     

Synthesis of Tetrahydrofuran and Tetrahydropyran Derivatives Catalyzed by Tungstophosphoric Acid in Ionic Liquid

Synthesis of tetrahydrofuran and tetrahydropyran derivatives catalyzed by tungstophosphoric acid （H3PW12040） were conveniently performed with high yield from the corresponding unsaturated alcohols in ionic liquid. Sufuric acid （H2SO4）, trifluoromathanesulfonic acid （TfOH） and p-toluenesulfonic acid （TsOH） were also explored for preparing these products in ionic liquid. The catalysts and ionic liquid can be easily recovered and reused.