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1.
Ionic Fluids Containing Both Strongly and Weakly Interacting Ions of the Same Charge Have Unique Ionic and Chemical Environments as a Function of Ion Concentration 下载免费PDF全文
Dr. Hui Wang Steven P. Kelley Jimmy W. Brantley III Dr. Gregory Chatel Dr. Julia Shamshina Dr. Jorge F. B. Pereira Varun Debbeti Prof. Allan S. Myerson Prof. Robin D. Rogers 《Chemphyschem》2015,16(5):993-1002
Liquid multi‐ion systems made by combining two or more salts can exhibit charge ordering and interactions not found in the parent salts, leading to new sets of properties. This is investigated herein by examining a liquid comprised of a single cation, 1‐ethyl‐3‐methylimidazolium ([C2mim]+), and two anions with different properties, acetate ([OAc]?) and bis(trifluoromethylsulfonyl)imide ([NTf2]?). NMR and IR spectroscopy indicate that the electrostatic interactions are quite different from those in either [C2mim][OAc] or [C2mim][NTf2]. This is attributed to the ability of [OAc]? to form complexes with the [C2mim]+ ions at greater than 1:1 stoichiometries by drawing [C2mim]+ ions away from the less basic [NTf2]? ions. Solubility studies with molecular solvents (ethyl acetate, water) and pharmaceuticals (ibuprofen, diphenhydramine) show nonlinear trends as a function of ion content, which suggests that solubility can be tuned through changes in the ionic compositions. 相似文献
2.
Xiaobo Ji Craig E. Banks Debbie S. Silvester Leigh Aldous Christopher Hardacre Richard G. Compton 《Electroanalysis》2007,19(21):2194-2201
First, the direct and indirect electrochemical oxidation of ammonia has been studied by cyclic voltammetry at glassy carbon electrodes in propylene carbonate. In the case of the indirect oxidation of ammonia, its analytical utility of indirect for ammonia sensing was examined in the range from 10 and 100 ppm by measuring the peak current of new wave resulting from reaction between ammonia and hydroquinone, as function of ammonia concentration, giving a sensitivity 1.29×10?7 A ppm?1 (r2=0.999) and limit‐of‐detection 5 ppm ammonia. Further, the direct oxidation of ammonia has been investigated in several room temperature ionic liquids (RTILs), namely 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([C4mim] [BF4]), 1‐butyl‐3‐methylimidazolium trifluoromethylsulfonate ([C4mim] [OTf]), 1‐Ethyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide ([C2mim] [NTf2]), 1‐butyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide ([C4mim] [NTf2]) and 1‐butyl‐3‐methylimidazolium hexafluorophosphate ([C4mim] [PF6]) on a 10 μm diameter Pt microdisk electrode. In four of the RTILs studied, the cyclic voltammetric analysis suggests that ammonia is initially oxidized to nitrogen, N2, and protons, which are transferred to an ammonia molecule, forming NH via the protonation of the anion(s) (A?). However, in [C4mim] [PF6], the protonated anion was formed first, followed by NH . In all five RTILs, both HA and NH are reduced at the electrode surface, forming hydrogen gas, which is then oxidized. The analytical ability of this work has also been explored further, giving a limit‐of‐detection close to 50 ppm in [C2mim] [NTf2], [C4mim] [OTf], [C4mim] [BF4], with a sensitivity of ca. 6×10?7 A ppm?1 (r2=0.999) for all three ionic liquids, showing that the limit of detection was ca. ten times larger than that in propylene carbonate since ammonia in propylene carbonate might be more soluble in comparison with RTILs when considering the higher viscosity of RTILs. 相似文献
3.
Liyong Yuan Jing Peng Ling Xu Maolin Zhai Jiuqiang Li Genshuan Wei 《Radiation Physics and Chemistry》2009,78(12):1133-1136
The radiation effect on a hydrophobic room-temperature ionic liquid (RTIL), 1-butyl-3-methyl-imidazolium bis[(trifluoromethyl)sulfonyl]imide ([C4mim][NTf2]), was studied by γ-irradiation under nitrogen atmosphere. Accompanied by color darkening and increase of light absorbance in a wide wavelength range, a distinct absorption peak at around 290 nm for irradiated [C4mim][NTf2] appeared when acetonitrile was used as solvent, and the intensity of the peak enhanced with increasing dose. The spectrophotometric study on the irradiated RTILs containing 1,3-dialkylimidazolium cations associated with different inorganic anions revealed that the peak is ascribed to the radiolysis products of the [C4mim]+. And the wavelength of the peak was affected by alkyl chain length on imidazolium cation, while the intensity of the peak was influenced by anions. With incorporating a little amounts of oxidants, such as KMnO4 and HNO3 into irradiated [C4mim][NTf2], the intensity of the peak at 290 nm decreased obviously and the decoloration of [C4mim][NTf2] occurred, suggesting that the peak at 290 nm is assigned to the colored species and the species can be oxidized. 相似文献
4.
Ionic Liquid‐based Microchannels for Highly Sensitive and Fast Amperometric Detection of Toxic Gases
Mengchen Ge Ghulam Hussain D. Brynn Hibbert Debbie S. Silvester Chuan Zhao 《Electroanalysis》2019,31(1):66-74
Ionic liquid (IL)‐based microchannels sensors have been fabricated and employed for the detection of toxic ammonia (NH3) and hydrogen chloride (HCl) gases, with enhanced sensitivity and response times compared to conventional electrodes. Electrochemical techniques were employed to understand the behaviour of these highly toxic gases in two ionic liquids, [C4mpyrr][NTf2] and [C2mim][NTf2], on a gold modified microchannels electrode. The limits of detection (LODs) obtained in [C4mpyrr][NTf2] for NH3 (3.7 ppm) and in [C2mim][NTf2] for HCl (3.6 ppm) were lower than the current Occupational Safety and Health Administration Permissible Exposure Limit (OSHA PEL) for the two gases (25 ppm for NH3 and 5 ppm for HCl). The response time of the sensor is 15 s with a sensitivity of 143 nA ppm?1 and 14 nA ppm?1 for HCl and NH3, respectively. These results demonstrate the superiority of IL‐based microchannels sensors for detecting toxic gases, when compared to commercially available sensors or traditional IL‐based sensor designs, where high sensitivity or fast response time is still a challenge. 相似文献
5.
1-烷基-3-甲基咪唑双三氟甲基磺酰胺型离子液体(Cnmim][NTf2])被认为是最有希望用于核燃料循环中的分离试剂之一, 虽然其化学结构在辐照过程中变化不大, 但在受到γ辐照后会发生明显的变色, 因此有必要研究该类离子液体的变色原因. 本文以60Co为辐照源, 系统研究了辐照后不同C(1)-烷基链长和咪唑环上C(2)位上的H被甲基取代后离子液体的紫外-可见(UV-Vis)吸收光谱行为, 并结合辐照后离子液体荧光光谱和质谱的变化, 分析了导致该类离子液体辐照后颜色加深的原因. 结果表明, 随着咪唑环上C(1)―烷基链长度和剂量增大, 离子液体颜色加深; 而C(2)位上的H被甲基取代后颜色明显变浅. 辐照后咪唑型离子液体的变色主要来自于辐照后产生的烷基侧链含双键的咪唑阳离子, 咪唑阳离子二聚体和含氟咪唑化合物. 此外, γ辐照引起咪唑阳离子易发生π-π堆积, 而聚集态含量增加也会引起颜色加深. 相似文献
6.
《The Journal of chemical thermodynamics》2007,39(6):866-877
Heat capacities in a range of temperatures of (5 to 370) K, enthalpies and temperatures of phase transitions for 1-ethyl-3-methylimidazolium bis(triflamide) ([C2mim][NTf2]) and 1-octyl-3-methylimidazolium bis(triflamide) ([C8mim][NTf2]) have been determined by adiabatic calorimetry. [C2mim][NTf2] has been found to form four crystalline phases with different fusion temperatures. Formation of the phases can be controlled by the temperature of annealing during crystallization. [C8mim][NTf2] forms three sequences of crystalline modifications, each including two polymorphs. Based on results of the measurements, thermodynamic functions for the compounds under study have been calculated.A heat-capacity anomaly near T = 230 K reported earlier for [C4mim][NTf2] and [C6mim][NTf2] have been found in some crystalline modifications of both the studied compounds. The position of the anomaly depends on the temperature of annealing of the crystals. 相似文献
7.
Nathan T. Scharf Annegret Stark Markus M. Hoffmann 《Journal of solution chemistry》2013,42(10):2034-2056
A calorimetric study of dissolution of the ionic liquids (ILs) 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([C2mim][NTf2]), 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([C6mim][NTf2]), and 1-hexyl-3-methylimidazolium tris(trifluoromethylsulfonyl)methide ([C6mim][CTf3]) into chloroform (CHCl3) is presented with particular focus on [C2mim][NTf2]. The interpretation of the calorimetric data for [C2mim][NTf2] was aided by additional NMR self-diffusion measurements and viscosity measurements that through the Stokes–Einstein equation provided information about the average size of the species present. It is evident that the main equilibrium species are ion pairs and aggregates. An estimate for the enthalpy contribution from aggregate formation for [C2mim][NTf2] was found to be ?2.09 kJ per mol of added IL at 288.2 K and slightly decreasing in magnitude to ?1.11 kJ·mol?1 at 318.2 K. While all three ILs release heat upon dissolution into CHCl3, different temperature trends are observed demonstrating the fine balance of competing contributions from breaking IL interactions, cavity formation for the solutes to reside in, and the establishment of new solute–solvent interactions. 相似文献
8.
Alok Rout Satyabrata Mishra K. A. Venkatesan M. P. Antony N. K. Pandey 《Journal of solution chemistry》2018,47(2):373-386
Tri-n-butylphosphate (TBP) in an ionic liquid (IL) has been proposed as a suitable alternative for the solvent extraction of actinides from nitric acid solutions. This paper reports the detailed investigations on the physicochemical and hydrodynamic properties of the solvent system containing TBP in 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C4mim][NTf2]) IL. The properties such as density, viscosity, phase separation time (PST), etc., were measured for irradiated and unirradiated solvent phases composed of TBP, [C4mim][NTf2] and 1.1 mol·L–1 TBP in [C4mim][NTf2]. The results are compared with the values obtained in acid-equilibrated IL phases. ATR–FTIR spectroscopy and dynamic light scattering measurement of the IL phase were employed to characterize the interactions among the IL, TBP and nitric acid medium, and the aggregate size of the adduct formed in the IL phase. 相似文献
9.
We report on the abrasive stripping voltammetry (AbrSV) of six different solid compounds of widely different natures in room temperature ionic liquids (RTILs). Copper as a metal representative, Prussian blue as a typical inorganic complex, indigo as an organic dye model, and anthracene, pyrene, and 9,10‐diphenylanthracene as the typical representatives of aromatic hydrocarbons were chosen in this study. They were immobilized on a gold electrode surface by mechanical abrasion and their subsequent voltammetric measurements were carried out in the ionic liquid [C4mim][NTf2], 1‐butyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide. The present work demonstrates that RTILs provide an excellent electrochemical solvent environment for abrasive stripping voltammetric analysis; in particular, the much wider potential windows in RTILs as compared to aqueous media greatly enhance the analytical applicability of the AbrSV technique. 相似文献
10.
Chen Hou Rongjun Qu Chunnuan Ji Changmei Sun Chunhua Wang 《Journal of polymer science. Part A, Polymer chemistry》2008,46(8):2701-2707
An ionic liquid, 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([C4mim] [BF4]), was first used as the solvent in azobisisobutyronitrile (AIBN)‐initiated reverse atom transfer radical polymerization (RATRP) of acrylonitrile with FeCl3/succinic acid (SA) as the catalyst system. The polymerization in [C4mim][BF4] proceeded in a well‐controlled manner as evidenced by kinetic studies. Compared with the polymerization in bulk, the polymerization in [C4mim][BF4] not only showed the best control of molecular weight and its distribution but also provided rather rapid reaction rate with the ratio of [C4mim][BF4] at 200:1:2:4. The polymerization apparent activation energies in [C4mim][BF4] and bulk were calculated to be 48.2 and 55.7 kJ mol?1, respectively. Polyacrylonitrile obtained was successfully used as a macroinitiator to proceed the chain extension polymerization in [C4mim][BF4] via a conventional ATRP process. [C4mim][BF4] and the catalyst system could be easily recycled and reused after simple purification and had no effect on the living nature of polymerization. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2701–2707, 2008 相似文献
11.
Room temperature ionic liquid as a novel medium for liquid/liquid extraction of metal ions 总被引:2,自引:0,他引:2
Room temperature ionic liquids (RTILs) have been used as novel solvents to replace traditional volatile organic solvents in organic synthesis, solvent extraction, and electrochemistry. The hydrophobic character and water immiscibility of certain ionic liquids allow their use in solvent extraction of hydrophobic compounds. In this work, a typical room temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate [C4mim][PF6], was used as an alternative solvent to study liquid/liquid extraction of heavy metal ions. Dithizone was employed as a metal chelator to form neutral metal-dithizone complexes with heavy metal ions to extract metal ions from aqueous solution into [C4mim][PF6]. This extraction is possible due to the high distribution ratios of the metal complexes between [C4mim][PF6] and aqueous phase. Since the distribution ratios of metal dithiozonates between [C4mim][PF6] and aqueous phase are strongly pH dependent, the extraction efficiencies of metal complexes can be manipulated by tailoring the pH value of the extraction system. Hence, the extraction, separation, and preconcentraction of heavy metal ions with the biphasic system of [C4mim][PF6] and aqueous phase can be achieved by controlling the pH value of the extraction system. Preliminary results indicate that the use of [C4mim][PF6] as an alternate solvent to replace traditional organic solvents in liquid/liquid extraction of heavy metal ions is very promising. 相似文献
12.
Silvester DS Aldous L Hardacre C Compton RG 《The journal of physical chemistry. B》2007,111(18):5000-5007
The electrochemical oxidation of dissolved hydrogen gas has been studied in a range of room-temperature ionic liquids (RTILs), namely [C(2)mim][NTf(2)], [C(4)mim][NTf(2)], [N(6,2,2,2)][NTf(2)], [P(14,6,6,6)][NTf(2)], [C(4)mpyrr][NTf(2)], [C(4)mim][BF(4)], [C(4)mim][PF(6)], [C(4)mim][OTf], and [C(6)mim]Cl on a platinum microdisk electrode of diameter 10 microm. In all cases, except [C(6)mim]Cl, a broad quasi-electrochemically reversible oxidation peak between 0.3 to 1.3 V vs Ag was seen prior to electrode activation ([C(6)mim]Cl showed an almost irreversible wave). When the electrode was pre-anodized ("activated") at 2.0 V vs Ag for 1 min, the peak separations became smaller, and the peak shape became more electrochemically reversible. It is thought that the electrogenerated protons chemically combine with the anions (A-) of the RTIL. The appearance and position of the reverse (reduction) peak on the voltammograms is thought to depend on three factors: (1) the stability of the protonated anion, HA, (2) the position of equilibrium of the protonation reaction HA<==> H+ + A- , and (3) any follow-up chemistry, e.g., dissociation or reaction of the protonated anion, HA. This is discussed for the five different anions studied. The reduction of HNTf(2) was also studied in two [NTf(2)]- -based RTILs and was compared to the oxidation waves from hydrogen. The results have implications for the defining of pKa in RTIL media, for the development of suitable reference electrodes for use in RTILs, and in the possible amperometric sensing of H2 gas. 相似文献
13.
Song and Mason equation of state (EOS) with a simple modification has been extended to modelling PVT properties of ionic liquids (ILs). The considered ILs are [C1mim][MeSO4], [C1mim][CH3OC2H5SO4], [C1mim][(CH3)2PO4], [C2mim][MeSO4], [C2mim][BF4], [C2mim][SCN], [C2eim][NTf2], [C4mim][C(CN)3], [C4mim][CF3SO3], [C4mim][SCN], [C5mim][NTf2], [C8mim][NTf2], [(C6H13)3P(C14H29)][Cl], [(C6H13)3P(C14H29)][NTf2], [(C6H13)3P(C14H29)][Ac], [C3mpyr][NTf2], [C4mpyr][NTf2] and [Py][C2H5OC2H4SO4]. Three temperature-dependent parameters in the proposed EOS have been scaled as functions of reduced temperature with the use of the law of corresponding states. It is shown that the knowledge of just critical temperature and critical density is sufficient to predict the PVT properties of these ILs. The overall average absolute deviation of calculated densities from literature values for 1347 data points of 18 ILs was found to be 0.58%. The predicted density of ILs from proposed EOS has been compared with those obtained by other literature work. Moreover, we indicate that the Zeno line regularity can well be predicted by proposed model for ILs. 相似文献
14.
[C12mim][BF4], [C8mim][BF4], and [C4mim][BF4] were first applied as reaction media for atom transfer radical polymerization using activators regenerated by electron transfer (ARGET ATRP) of acrylonitrile (AN) with 1,1,4,7,7‐pentamethyldiethylenetriamine (PMDETA) as both ligand and reducing agent in the presence of air. The rate of polymerization in [C12mim][BF4] was considerably faster than in [C8mim][BF4] and [C4mim][BF4]. ARGET ATRP of AN in [C12mim][BF4] were better controlled than in [C8mim][BF4] and [C4mim][BF4] under the same experimental conditions. With an increase in the content of PMDETA, the polymerization provided an accelerated reaction rate and a broader polymer molecular weight distribution. A slow polymerization rate and a broad polydispersity index were observed using TMEDA instead of PMDETA as both ligand and reducing agent. There was an obvious induction period with CuCl2 instead of CuBr2 as catalyst. Well‐defined PAN‐b‐PMMA with higher molecular weight at 104,560 and relatively broader distribution at 1.35 was successfully prepared with PAN as macroinitiator via ARGET ATRP in [C12mim][BF4] in the presence of air. The resultant fibers were obtained with the fineness at 1.17dtex and the tenacity at 6.03cN · dtex?1. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
15.
Nobuyuki Matubayasi 《Chemical record (New York, N.Y.)》2019,19(4):723-734
Spatial decomposition is conducted for the electrical conductivity. The contribution per ion pair at a certain distance is identified in terms of a two‐body velocity time correlation function and is integrated over the whole distance of the ion pair to provide the cross‐correlation term of the conductivity. The spatial‐decomposition formula is an exact expression at any concentrations of ions and incorporates physically appealing pictures in the space domain into the theory of time correlation functions. Illustrative analyses are presented for 1m NaCl aqueous solution and the [C4mim][NTf2] ionic liquid. The contrast between the two systems is discussed for the time and spatial ranges of correlations, and it is shown that the ion‐pair contribution to the conductivity for the [C4mim][NTf2] system is not localized and extends beyond the first coordination shell of the cation‐anion pair. 相似文献
16.
Effect of Ionic Liquid Anion Type in the Performance of Solid Polymer Electrolytes Based on Poly(Vinylidene fluoride‐trifluoroethylene) 下载免费PDF全文
A. V. Machado J. M. S. S. Esperança M. M. Silva S. Lanceros‐Méndez 《Electroanalysis》2015,27(2):457-464
The effect of different anions within the ionic liquid in the characteristics of solid polymer electrolytes (SPEs) based on P(VDF‐TrFE) has been investigated. 1‐ethyl‐3‐methylimidazolium acetate, [C2mim][OAc], 1‐ethyl‐3‐methylimidazolium triflate, [C2mim][(CF3SO3)], 1‐ethyl‐3‐methylimidazolium lactate, [C2mim][Lactate], 1‐ethyl‐3‐methylimidazolium thiocyanate, [C2mim][SNC] and 1‐ethyl‐3‐methylimidazolium hydrogen sulfate [C2mim][HSO4] have been used in SPE prepared by solvent casting. The polymer phase, thermal and electrochemical properties of the SPE have been determined. The thermal and electrical properties of the SPEs strongly depend on the selected IL, as determined by their different interactions with the polymer matrix. The room temperature ionic conductivity increases in the following way for the different anions: [SNC]>[CF3SO3)]>[HSO4]>[Lactate]>[OAc], which is mainly dependent on the viscosity of the ionic liquid. 相似文献
17.
Two new Eu‐based ionic liquid systems, [C4mim][DTSA] : [Eu(DTSA)3] and 2[C4mim] [DTSA] : [Eu(DTSA)3] were synthesized at 120° under inert conditions from 1‐butyl‐1‐methylimidazolium ditoluenesulfonylamide ([C4mim][DTSA]). The identity and purity of the synthesized compounds were confirmed by elemental analysis, IR, Raman, and 1H‐NMR spectroscopy. As they solidify below 100° as glasses they qualify as ionic liquids. Fluorescence measurements show that the materials exhibit a strong red luminescence of high color purity. Therefore, they have the potential to be used for optical applications such as in emission displays. 相似文献
18.
讨论了辛基(苯基)-N,N-二异丁基胺甲酰基甲基氧化膦(CMPO)/1-烷基-3-甲基咪唑双(三氟甲烷磺酰)亚胺盐([Cnmim][NTf2],n=2,8,12)萃取体系分别对硝酸溶液中的铕离子(Eu3+)和铀酰根离子(UO22+)的萃取行为。主要研究了硝酸浓度、接触时间、温度、CMPO浓度对CMPO/[Cnmim][NTf2]体系萃取性能的影响,并选取CMPO/[C2mim][NTf2]体系对模拟高放废液中的镧锕元素进行了萃取分离。结果表明:随着离子液体侧链长度增长,萃取平衡时间逐渐延长;CMPO/[C2mim][NTf2]体系对Eu3+的萃取是放热反应,萃取率随酸度增加而逐渐降低,对UO22+则是吸热反应,萃取率随酸度增加而逐渐升高;通过机理研究,推测出对Eu3+的萃取反应是离子交换,而对UO22+的萃取反应则是中性配位;CMPO/[C2mim][NTf2]体系能有效的萃取模拟高放废液中的镧系、锕系元素,且在高酸下有一定的镧锕分离效果。 相似文献
19.
Theo Rodopoulos Dr. Leanne Smith Michael D. Horne Thomas Rüther Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(12):3815-3826
This paper reports on the electrodeposition of aluminium on several substrates from the air‐ and water‐stable ionic liquids 1‐propyl‐1‐methylpiperidinium bis(trifluoromethylsulfonyl)amide ([C3mpip][NTf2]) and 1‐butyl‐1‐methylpyrrolidinium bis(trifluoromethylsulfonyl)amide ([C4mpyr][NTf2]), which contain anhydrous AlCl3. At an AlCl3 concentration of 0.75 molal, no evidence for aluminium electrodeposition was observed in either system at room temperature. However, aluminium electrodeposition becomes feasible upon heating the samples to 80 °C. Aluminium electrodeposition from bis(trifluoromethylsulfonyl)amide‐based ionic liquids that contain AlCl3 has previously been shown to be very dependent upon the AlCl3 concentration and has not been demonstrated at AlCl3 concentrations below 1.13 molal. The dissolution of AlCl3 in [C3mpip][NTf2] and [C4mpyr][NTf2] was studied by variable‐temperature 27Al NMR spectroscopy to gain insights on the electroactive species responsible for aluminium electrodeposition. A similar change in the aluminium speciation with temperature was observed in both ionic liquids, thereby indicating that the chemistry was similar in both. The electrodeposition of aluminium was shown to coincide with the formation of an asymmetric four‐coordinate aluminium‐containing species with an 27Al chemical shift of δ=94 and 92 ppm in the [C3mpip][NTf2]–AlCl3 and [C4mpyr][NTf2]–AlCl3 systems, respectively. It was concluded that the aluminium‐containing species that give rise to these resonances corresponds to the electroactive species and was assigned to [AlCl3(NTf2)]?. 相似文献