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  • [Wiley数据库][2012]Ion Transfer Voltammetry Associated with Two Polarizable Interfaces Within Water and Moderately Hydrophobic Ionic Liquid Systems
  • 更新时间:2016-02-23;信息类型:期刊文章
  • An electrochemical system composed of two polarizable interfaces (the metallic electrodejwater and waterjionic liquid interfaces), namely two-polarized-interface (TPI) technique, has been proposed to explore the ion transfer processes between water and moderately hydrophobic ionic liquids(WjmIL), typically 1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (C8mimC1C1N) and 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (C6mimC1C1N). Within the classic four-electrode system, it is not likely that the ion transfer information at the WjmIL interface can be obtained due to an extremely narrow polarized potential window (ppw) caused by these moderately hydrophobic ionic components. In this article, we show that TPI technique has virtually eliminated the ppw limitation based on a controlling step of concentration polarization at the electrodejwater interface. With the aid of this technique, the formal ion transfer potential differences between C1C1N and Cnmim+ (n=6, 8) were accurately determined for 356 mV and 420 mV at a corresponding interface (WjC6mimC1C1N and Wj C8mimC1C1N). Besides, this technique is used to monitor electrochemical polarization at the two WjmIL systems, which exhibits an adaptable polarizability (i.e., a conversion from a nonpolarized interface to a polarized interface). Some of the typical anion transfers at the WjC8mimC1C1N interface have also been investigated, as they are particularly important for ion extraction. The experimental results indicate that this facile TPI technique offers a general avenue to explore ion transfer in multifarious biphasic systems.
  • 链接地址:http://www.ionicliquid.org/download/c-articles/2016-02-23/330.html
  • [Wiley数据库][2012]The Essential Role of Hydrogen-Bonding Interaction in the Extractive Separation of Phenolic Compounds by Ionic Liquid
  • 更新时间:2016-02-23;信息类型:期刊文章
  • Separating phenols or even their homologs is an important process in environmental conservation and biomass utilization, and it has become one fascinating application of ionic liquids (ILs). Nevertheless, its underlying mechanism still needs to be elucidated at the molecular level. This work conducted a theoretical study on the interaction between ILs and phenols by quantum chemical calculations, using tocopherols as model compounds. Calculation results from geometry, electrostatic potential, natural bond orbital, atoms in molecules and energy analyses and their accordance with extraction experiments indicated the essential role of hydrogen-bonding interaction in extracting tocopherols and distinguishing the homologs by IL. The polarizable continuum model and conductor-like screening model for real solvents studies showed that the mechanism still holds when considering the solvation effect. Furthermore, with the aid of theoretical calculation, more efficient extractants, 1-ethyl-3-methylimidazolikum glycinate ([emim]Gly) and 1-ethyl-3-methylimidazolikum alaninate ([emim]Ala), were developed for the separation of tocopherol homologs.
  • 链接地址:http://www.ionicliquid.org/download/c-articles/2016-02-23/329.html
  • [Wiley数据库][2011]Homogeneous synthesis and characterization of starch acetates in ionic liquid without catalysts
  • 更新时间:2016-01-25;信息类型:期刊文章
  • Homogeneous modification of corn starch with acetic anhydride was performed in ionic liquids 1-butyl-3-methylimidazolium chloride (BMIMCl) without catalysts. The results indicated that the pretreatment of starch, which starch was dissolved in BMIMCl at 1058C for 2 h before reaction, provided feasible reaction environment for starch functionalization. Optimum modification conditions for maximum degree of substitute (DS 2.11) wereshown as following: acetic anhydride/anhydroglucose units (AGU) molar ratio 5:1, reaction temperature 1058C and reaction time 2 h. The pretence of acetyl groups in starch products was confirmed by FTIR and 1H NMR spectroscopy. SEM and XRD data showed that the crystalline structure of native starch was disrupted and new structure was formed during the dissolution and modification processes. The higher DS due to acetylation had a beneficial effect on the thermal stability of samples.
  • 链接地址:http://www.ionicliquid.org/download/c-articles/2016-01-25/328.html
  • [Wiley数据库][2011]Determination of insecticides in water using in situ halide exchange reaction-assisted ionic liquid dispersive liquid–liquid microextraction followed by highperformance liquid chromatography
  • 更新时间:2016-01-25;信息类型:期刊文章
  • A dispersive liquid–liquid microextraction (DLLME) method using in situ halide exchange reaction to form ionic liquid (IL) extraction phase was developed to determine four insecticides (i.e. methoxyfenozide, tetrachlorvinphos, thiamethoxam, and diafenthiuron) in water samples. The preconcentration procedure, followed by high-performance liquid chromatography and variable wavelength detectors (VWD), enabled the formation of the immiscible IL extraction phase; the insecticides were transferred into the IL phase simultaneously, which enhanced the efficiency and sufficiency, greatly shortening the operation time. The experimental parameters affecting the extraction efficiency including volume of extraction IL, extraction and centrifugation times, volume of the sample solution and exchanging reagent, and addition of organic solvent and salt were investigated and optimized. Under optimized conditions, the extractions yielded recoveries of the target analytes from 82 to 102%. The calibration curves were linear, and the correlation coefficient ranged from 0.9990 to 0.9999 under the concentration levels of 5–200mg/L. The relative standard deviation (n56) was 2.9–4.6%. The limits of detection (LODs) for the four insecticides were between 0.98 and 2.54mg/L.
  • 链接地址:http://www.ionicliquid.org/download/c-articles/2016-01-25/327.html
  • [Wiley数据库][2011]Novel approach to improve the detection of colchicine via online coupling of ionic liquidbased single-drop microextraction with capillary electrophoresis
  • 更新时间:2016-01-25;信息类型:期刊文章
  • A novel approach based on ionic liquid-single-drop microextraction (IL-SDME) online coupling with capillary electrophoresis (CE) was used to determine a toxic alkaloid – colchicine. The IL-SDME procedure was optimized by extraction solvent, drop volume controlling, sample volume and pH, extraction time, and ionic strength. Under optimum conditions, enrichment factor was as much as 41-fold with a relative standard deviation of 2.8% (n53). Linear range of response was observed from 1 to 100 mg/mL, with detection limit of 0.25mg/mL and correlation coefficient (R2) of 0.9994. The extraction of colchicine from spiked Lanzhou lily sample was performed and obtaining good result with an average recovery rate of 102.4 and 98.8% at 5 and 50mg/mL, respectively. Comparing with the previous methods, IL-SDME-CE is really a convenient, economical, and environmentally benign way for determining colchicine.
  • 链接地址:http://www.ionicliquid.org/download/c-articles/2016-01-25/326.html
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