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Sample records for 1-butyl-3-methylimidazolium ionic liquids

  1. Side chain fluorination and anion effect on the structure of 1-butyl-3-methylimidazolium ionic liquids

    NASA Astrophysics Data System (ADS)

    Weber, Henry; Hollóczki, Oldamur; Pensado, Alfonso S.; Kirchner, Barbara

    2013-08-01

    We present a comprehensive molecular dynamics simulation study on 1-butyl-3-methylimidazolium ionic liquids and their fluorinated analogs. The work focused on the effect of fluorination at varying anions. The main findings are that the fluorination of the cations side chain increases overall structuring, especially the aggregation of cation side chain. Furthermore, large and weakly coordinating anions tend to occupy on-top positions of the cation and decrease the aggregation of cation side chains, most likely due to enhanced alkyl-anion interaction.

  2. FE-SEM observation of swelled seaweed using hydrophilic ionic liquid; 1-butyl-3-methylimidazolium tetrafluoroborate.

    PubMed

    Takahashi, Chisato; Shirai, Takashi; Fuji, Masayoshi

    2013-01-01

    The method to observe the exact morphology of swelled seaweed as an example of biological material by field emission scanning electron microscopy (FE-SEM) with the aid of hydrophilic ionic liquid (IL); 1-butyl-3-methylimidazolium tetrafluoroborate is reported. Seaweed was first swelled in 3.5% NaCl solution and then treated with the IL and water mixture in 1:7 weight ratios and centrifuged to remove the excess IL solution. Thus treated seaweed maintained its morphology even at high magnification and did not show drying in the FE-SEM chamber. This observation technique might be useful for various kinds of biological materials to be observed under FE-SEM.

  3. Phase behavior and microstructure of microemulsions containing the hydrophobic ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate.

    PubMed

    Anjum, Nishat; Guedeau-Boudeville, Marie-Alice; Stubenrauch, Cosima; Mourchid, Ahmed

    2009-01-08

    The phase behavior and microstructure of the ternary system water/1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF(6))/Triton X-100 was studied as a function of temperature and ionic liquid (IL) mass fraction alpha. In the present study, a hydrophobic IL instead of commonly used organic solvents such as n-alkanes is used. The fish-shaped region is distorted at low and high values of alpha, whereas it is symmetric at intermediate alpha. With increasing alpha, the extension of the three-phase region decreases regarding the surfactant concentration range, whereas it increases regarding the temperature range. For comparison the phase behavior of two ternary water/bmimPF(6)/alkyl oligoethyleneoxide (C(i)E(j)) systems has been investigated. Our results are compared with those obtained for water/n-alkane/C(i)E(j) and IL/n-alkane/C(i)E(j) systems, respectively.

  4. Radiation effects on microcrystalline cellulose in 1-butyl-3-methylimidazolium chloride ionic liquid.

    PubMed

    Hao, Yan; Peng, Jing; Ao, Yinyong; Li, Jiuqiang; Zhai, Maolin

    2012-11-06

    The radiation processing of cellulose in ionic liquids (ILs) demands a comprehensive knowledge of radiation effects on cellulose in ILs. Herein, gamma radiation-induced degradation kinetics of microcrystalline cellulose (MCC) in 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) was studied by viscometry. The intrinsic viscosity of MCC in [Bmim]Cl decreased slightly with increasing dose; while chemical structure and crystalline state of cellulose has no obvious change up to 300 kGy. The radiation degradation rate constant (k) of MCC in [Bmim]Cl was 2.60×10(-7)/kGy, lower than that of solid cellulose, but higher than that in N-methylmorpholine-N-oxide (NMMO) solvent. Furthermore, k value decreased to 1.12×10(-7)/kGy in dimethyl sulfoxide (DMSO)/[Bmim]Cl system due to the free radicals scavenging of DMSO. The radicals generated during irradiation play main role in the radiation degradation of MCC in [Bmim]Cl. This work provides a new way to control the average molecular weight of cellulose by radiation-induced degradation of cellulose in ILs.

  5. Hydrophobic ionic liquids based on the 1-butyl-3-methylimidazolium cation for lithium/seawater batteries

    NASA Astrophysics Data System (ADS)

    Zhang, Yancheng; Urquidi-Macdonald, Mirna

    Two hydrophobic ionic liquids (room temperature molten salts) based on 1-butyl-3-methylimidazolium cation (BMI +), BMI +PF 6- and BMI +Tf 2N -, were used in developing a highly efficient lithium anode system for lithium/seawater batteries. The lithium anode system was composed of lithium metal/ionic liquid/Celgard membrane. Both BMI +PF 6-and BMI +Tf 2N - maintained high apparent anodic efficiency (up to 100%) under potentiostatic polarization (at +0.5 V versus open-circuit potential (OCP)) in a 3% NaCl solution. Eventually, traces of water contaminated the ionic liquid and a bilayer film (LiH and LiOH) on the lithium surface was formed, decreasing the rate of lithium anodic reaction and hence the discharge current density. BMI +Tf 2N - prevented traces of water from reaching the lithium metal surface longer than BMI +PF 6- (60 h versus 7 h). However, BMI +PF 6- was better than BMI +Tf 2N - in keeping a constant current density (˜0.2 mA cm -2) before the traces of water contaminated the lithium surface due to the non-reactivity of BMI +PF 6- with the lithium metal that kept the bare lithium surface. During the discharge process, BMI +PF 6- and BMI +Tf 2N - acted as ion transport media of Li +, Cl -, OH - and H 2O, but did not react with them because of the excellent chemical stability, high conductivity, and high hydrophobicity of these two ionic liquids. Both BMI +PF 6- and BMI +Tf 2N - gels were tentative approaches used to delay the traces of water coming in contact with the lithium surface.

  6. Aqueous Solutions of the Ionic Liquid 1-butyl-3-methylimidazolium Chloride Denature Proteins

    SciTech Connect

    Baker, Gary A; Heller, William T

    2009-01-01

    As we advance our understanding, ionic liquids (ILs) are finding ever broader scope within the chemical sciences including, most recently, pharmaceutical, enzymatic, and bioanalytical applications. With examples of enzymatic activity reported in both neat ILs and in IL/water mixtures, enzymes are frequently assumed to adopt a quasi-native conformation, even if little work has been carried out to date toward characterizing the conformation, dynamics, active-site perturbation, cooperativity of unfolding transitions, free energy of stabilization, or aggregation/oligomerization state of enzymes in the presence of an IL solvent component. In this study, human serum albumin and equine heart cytochrome c were characterized in aqueous solutions of the fully water-miscible IL 1-butyl-3-methylimidazolium chloride, [bmim]Cl, by small-angle neutron and X-ray scattering. At [bmim]Cl concentrations up to 25 vol.%, these two proteins were found to largely retain their higher-order structures whereas both proteins become highly denatured at the highest IL concentration studied here (i.e., 50 vol.% [bmim]Cl). The response of these proteins to [bmim]Cl is analogous to their behavior in the widely studied denaturants guanidine hydrochloride and urea which similarly lead to random coil conformations at excessive molar concentrations. Interestingly, human serum albumin dimerizes in response to [bmim]Cl, whereas cytochrome c remains predominantly in monomeric form. These results have important implications for enzymatic studies in aqueous IL media, as they suggest a facile pathway through which biocatalytic activity can be altered in these nascent and potentially green electrolyte systems.

  7. Synthesis and thermodynamic properties of a new task-specific ionic liquid 1-butyl-3-methylimidazolium salicylate

    NASA Astrophysics Data System (ADS)

    Wang, Xiao-Dan; Han, Chun; Fan, Hong-Tao

    2015-07-01

    Task-specific ionic liquid 1-butyl-3-methylimidazolium salicylate ([BMI]Sal) was synthesized in two steps. In the temperature range of 298.15-353.15 K, the density and surface tension for pure ionic liquid were determined and the thermodynamic properties of the ionic liquid were discussed in terms of Glasser's theory. The standard molar entropy and lattice energy for [BMI]Sal have been estimated. In addition, the thermal expansion coefficient, α = 5.53 × 10-4 K-1, calculated by the interstice model is in extreme agreement with α (experimental) = 5.50 × 10-4 K-1.

  8. Gold particle synthesis via reduction of gold salt in the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate aqueous solution.

    PubMed

    Xue, Yiguo; Du, Jimin; Zou, Hua; Wang, Xiaojun; Li, Zhonghao

    2012-06-01

    The formation of gold particles via reduction of HAuCl4 x 4H2O by ascorbic acid in the presence of ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate and sodium alginate has been studied. The shape of the synthesized particles could be tuned by controlling the reaction conditions. Specifically, the flowerlike gold particles can be synthesized by the present synthetic route. It demonstrates that both the ionic liquid and the sodium alginate play an important role for the formation of the flowerlike particles. The synthesized flowerlike particles show enhanced electroactivity for H2O2.

  9. Characterization of cellulose II nanoparticles regenerated from ionic liquid, 1-butyl-3-methylimidazolium chloride

    USDA-ARS?s Scientific Manuscript database

    Regenerated cellulose nanoparticles (RCNs) including both elongated fiber and spherical structures were prepared from microcrystalline cellulose (MCC)and cotton using 1-butyl-3-methylimidazolium chloride followed by high-pressure homogenization. The crystalline structure of RCNs was cellulose II in ...

  10. The gaseous enthalpy of formation of the ionic liquid 1-butyl-3-methylimidazolium dicyanamide from combustion calorimetry, vapor pressure measurements, and ab initio calculations.

    PubMed

    Emel'yanenko, Vladimir N; Verevkin, Sergey P; Heintz, Andreas

    2007-04-04

    Ionic liquids are attracting growing interest as alternatives to conventional molecular solvents. Experimental values of vapor pressure, enthalpy of vaporization, and enthalpy of formation of ionic liquids are the key thermodynamic quantities, which are required for the validation and development of the molecular modeling and ab initio methods toward this new class of solvents. In this work, the molar enthalpy of formation of the liquid 1-butyl-3-methylimidazolium dicyanamide, 206.2 +/- 2.5 kJ.mol-1, was measured by means of combustion calorimetry. The molar enthalpy of vaporization of 1-butyl-3-methylimidazolium dicyanamide, 157.2 +/- 1.1 kJ.mol-1, was obtained from the temperature dependence of the vapor pressure measured using the transpiration method. The latter method has been checked with measurements of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide, where data are available from the effusion technique. The first experimental determination of the gaseous enthalpy of formation of the ionic liquid 1-butyl-3-methylimidazolium dicyanamide, 363.4 +/- 2.7 kJ.mol-1, from thermochemical measurements (combustion and transpiration) is presented. Ab initio calculations of the enthalpy of formation in the gaseous phase have been performed for 1-butyl-3-methylimidazolium dicyanamide using the G3MP2 theory. Excellent agreement with experimental results has been observed. The method developed opens a new way to obtain thermodynamic properties of ionic liquids which have not been available so far.

  11. Comparison of autohydrolysis and ionic liquid 1-butyl-3-methylimidazolium acetate pretreatment to enhance enzymatic hydrolysis of sugarcane bagasse

    SciTech Connect

    Hashim, Muzna; Sun, Qining; Tao, Jingming; Wells, Jr., Tyrone; Shah, Aamer; Labbe, Nicole; Ragauskas, Arthur

    2016-11-02

    The aim of this work was to evaluate the efficiency of an ionic liquid (IL) 1-butyl-3-methylimidazolium acetate ([C4mim][OAc]) pretreatment (110 C for 30 min) in comparison to high severity autohydrolysis pretreatment in terms of delignification, cellulose crystallinity and enzymatic digestibility. The increase in severity of autohydrolysis pretreatment had positive effect on glucan digestibility, but was limited by the crystallinity of cellulose. [C4mim][OAc] pretreated sugarcane bagasse exhibited a substantial decrease in lignin content, reduced cellulose crystallinity, and enhanced glucan and xylan digestibility. Glucan and xylan digestibility was determined as 97.4% and 98.6% from [C4mim][OAc] pretreated bagasse, and 62.1% and 57.5% from the bagasse autohydrolyzed at 205 C for 6 min, respectively. The results indicated the improved digestibility and hydrolysis rates after [C4mim][OAc] pretreatment when compared against a comparable autohydrolyzed biomass.

  12. Comparison of autohydrolysis and ionic liquid 1-butyl-3-methylimidazolium acetate pretreatment to enhance enzymatic hydrolysis of sugarcane bagasse

    DOE PAGES

    Hashim, Muzna; Univ. of Tennessee, Knoxville, TN; Sun, Qining; ...

    2016-11-02

    The aim of this work was to evaluate the efficiency of an ionic liquid (IL) 1-butyl-3-methylimidazolium acetate ([C4mim][OAc]) pretreatment (110 C for 30 min) in comparison to high severity autohydrolysis pretreatment in terms of delignification, cellulose crystallinity and enzymatic digestibility. The increase in severity of autohydrolysis pretreatment had positive effect on glucan digestibility, but was limited by the crystallinity of cellulose. [C4mim][OAc] pretreated sugarcane bagasse exhibited a substantial decrease in lignin content, reduced cellulose crystallinity, and enhanced glucan and xylan digestibility. Glucan and xylan digestibility was determined as 97.4% and 98.6% from [C4mim][OAc] pretreated bagasse, and 62.1% and 57.5% frommore » the bagasse autohydrolyzed at 205 C for 6 min, respectively. The results indicated the improved digestibility and hydrolysis rates after [C4mim][OAc] pretreatment when compared against a comparable autohydrolyzed biomass.« less

  13. Anomalous Freezing of Nano-Confined Water in Room-Temperature Ionic Liquid 1-Butyl-3-Methylimidazolium Nitrate.

    PubMed

    Abe, Hiroshi; Takekiyo, Takahiro; Yoshimura, Yukihiro; Saihara, Koji; Shimizu, Akio

    2016-04-18

    Non-crystal formation of ice is investigated by simultaneous X-ray diffraction and differential scanning calorimetry measurements upon cooling to -100 °C. At room temperature, size-tunable water confinement (≈20 Å size) in a room-temperature ionic liquid (RTIL, 1-butyl-3-methylimidazolium nitrate, [C4 mim][NO3 ]) exists in a water-rich region (70-90 mol % D2 O). The confined water (water pocket) is characterized by almost monodispersive size distribution. In [C4 mim][NO3 ]-x mol % D2 O (70

  14. Glycine in 1-butyl-3-methylimidazolium acetate and trifluoroacetate ionic liquids: effect of fluorination and hydrogen bonding.

    PubMed

    Podgoršek, Ajda; Macchiagodena, Marina; Ramondo, Fabio; Costa Gomes, Margarida F; Pádua, Agílio A H

    2012-05-14

    The solvation of glycine in two ionic liquids (ILs), namely, 1-butyl-3-methylimidazolium acetate, [C(1)C(4)Im][OAc], and 1-butyl-3-methylimidazolium trifluoroacetate, [C(1)C(4)Im][TFA], was studied by a combination of experimental and theoretical methods. The solubility of glycine in both ILs was determined at 333.15 K to be (8.1±0.5) and (1.0±0.5) wt % in [C(1)C(4)Im][OAc] and [C(1)C(4)Im][TFA], respectively. By IR spectroscopy it was found that, when dissolved in the ILs, glycine was mainly present in its zwitterionic form. Structural and energetic aspects of the solvation of glycine in the ILs and in mixtures of ILs and water were investigated by ab initio calculations and molecular dynamic simulations. It was observed that the firstly solvation shell around glycine consisted predominantly of acetate or trifluoroacetate anions, which formed hydrogen bonds either with the carboxylic group of neutral glycine or with the protonated ammonium group of the zwitterionic form. When water is present in the solutions, hydrogen bonds between water and the anion prevail. The overall energy of the system was decomposed into its components between pairs of species. It was established that the dominant contribution to the interaction energy between glycine and the IL was due to hydrogen bonds with the anions and the statistics of hydrogen bonds were analysed. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Structural studies of 1-butyl-3-methylimidazolium tetrafluoroborate/TX-100/ p-xylene ionic liquid microemulsions.

    PubMed

    Gao, Yan'an; Zhang, Jin; Xu, Hongyan; Zhao, Xueyan; Zheng, Liqiang; Li, Xinwei; Yu, Li

    2006-07-17

    The ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF4) forms nonaqueous microemulsions with p-xylene, with the aid of the nonionic surfactant TX-100. The phase behavior of the ternary system is investigated, and three microregions of the microemulsions-ionic liquid-in-oil (IL/O), bicontinuous, and oil-in-ionic liquid (O/IL)-are identified by conductivity measurements, according to percolation theory. On the basis of a phase diagram, a series of IL/O microemulsions are chosen and characterized by dynamic light scattering (DLS). The size of aggregates increases on increasing the amount of added polar component (bmimBF(4)), which is a similar phenomenon to that observed for typical water-in-oil (W/O) microemulsions, suggesting the formation of IL/O microemulsions. The microstructural characteristics of the microemulsions are investigated by FTIR and 1H NMR spectroscopy. The results indicate that the interaction between the electronegative oxygen atoms of the oxyethylene (OE) units in TX-100 and the electropositive imidazolium ring may be the driving force for the solubilization of bmimBF4 into the core of the TX-100 aggregates. In addition, the micropolarity of the microemulsions is investigated by using methyl orange (MO) as a UV/Vis spectroscopic probe. A relatively constant polarity of the microemulsion droplets is obtained in the IL microemulsion. Finally, a plausible structure for the IL/O microemulsion is presented.

  16. Calorimetric determination of the enthalpy of 1-butyl-3-methylimidazolium bromide synthesis: a key quantity in thermodynamics of ionic liquids.

    PubMed

    Paulechka, Yauheni U; Kabo, Andrey G; Blokhin, Andrey V

    2009-11-05

    The enthalpy of the 1-butyl-3-methylimidazolium bromide [C(4)mim]Br ionic liquid synthesis reaction 1-methylimidazole (liq) + 1-bromobutane (liq) --> [C(4)mim]Br (liq) was determined in a homemade small-volume isoperibol calorimeter to be Delta(r)H degrees (298) = -87.7 +/- 1.6 kJ x mol(-1). The activation energy for this reaction in a homogeneous system E(A) = 73 +/- 4 kJ x mol(-1) was found from the results of calorimetric measurements. The formation enthalpies for the crystalline and liquid [C(4)mim]Br were determined from the calorimetric data: Delta(f)H degrees (298)(cr) = -178 +/- 5 kJ x mol(-1) and Delta(f)H degrees (298)(liq) = -158 +/- 5 kJ x mol(-1). The ideal-gas formation enthalpy of this compound Delta(f)H degrees (298)(g) = 16 +/- 7 kJ x mol(-1) was calculated using the methods of quantum chemistry and statistical thermodynamics. The vaporization enthalpy of [C(4)mim]Br, Delta(vap)H degrees (298) = 174 +/- 9 kJ x mol(-1), was estimated from the experimental and calculated formation enthalpies. It was demonstrated that vapor pressure of this ionic liquid cannot be experimentally determined.

  17. Free volume and phase transitions of 1-butyl-3-methylimidazolium based ionic liquids from positron lifetime spectroscopy.

    PubMed

    Yu, Yang; Beichel, Witali; Dlubek, Günter; Krause-Rehberg, Reinhard; Paluch, Marian; Pionteck, Jürgen; Pfefferkorn, Dirk; Bulut, Safak; Friedrich, Christian; Pogodina, Natalia; Krossing, Ingo

    2012-05-21

    Positron annihilation lifetime spectroscopy (PALS) was used to study a series of ionic liquids (ILs) with the 1-butyl-3-methylimidazolium cation ([C4MIM](+)) but different anions [Cl](-), [BF4](-), [PF6](-), [OTf](-), [NTf2](-), and [B(hfip)4](-) with increasing anion volumes. Changes of the ortho-positronium (o-Ps) lifetime parameters with temperature were observed for crystalline and amorphous (glass, supercooled, and normal liquid) states. Evidence for distinct phase transitions, e.g. melting, crystallization and solid-solid transitions, was observed in several PALS experiments. The o-Ps mean lifetime τ3 showed smaller values in the crystalline phase due to dense packing of the material compared to the amorphous phase. The o-Ps lifetime intensity I3 in the liquid state is clearly smaller than in the crystallized state. This behaviour can be attributed to a solvation of e(+) by the anions, which reduces the Ps formation probability in the normal and supercooled liquid. These phenomena were observed for the first time when applying the PALS technique to ionic liquids by us in one preliminary and in this work. Four of the ionic liquids investigated in this work ([BF4](-), [NTf2](-), [PF6](-) and [Cl](-) ILs) exhibit supercooled phases. The specific hole densities and occupied volumes of those ILs were obtained by comparing the local free volume with the specific volume from pressure-volume-temperature (PVT) experiments. From the o-Ps lifetime, the mean size vh of free volume holes of the four samples was calculated and compared with that calculated according to Fürth's hole theory. The hole volumes from both methods agree well. From the Cohen-Turnbull fitting of viscosity and conductivity against PALS/PVT results, the influence of the free volume on molecular transport properties was investigated.

  18. The effect of water on the microstructure of 1-butyl-3-methylimidazolium tetrafluoroborate/TX-100/benzene ionic liquid microemulsions.

    PubMed

    Gao, Yan'an; Li, Na; Zheng, Liqiang; Zhao, Xueyan; Zhang, Jin; Cao, Quan; Zhao, Mingwei; Li, Zhen; Zhang, Gaoyong

    2007-01-01

    The ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) forms nonaqueous microemulsions with benzene with the aid of nonionic surfactant TX-100. The phase diagram of the ternary system was prepared, and the microstructures of the microemulsion were recognized. On the basis of the phase diagram, a series of ionic liquid-in-oil (IL/O) microemulsions were chosen and characterized by dynamic light scattering (DLS), which shows a similar swelling behavior to typical water-in-oil (W/O) microemulsions. The existence of IL pools in the IL/O microemulsion was confirmed by UV/Vis spectroscopic analysis with CoCl2 and methylene blue (MB) as the absorption probes. A constant polarity of the IL pool is observed, even if small amounts of water are added to the microemulsion, thus suggesting that the water molecules are solubilized in the polar outer shell of the microemulsion, as confirmed by FTIR spectra. 1H NMR spectroscopic analysis shows that these water molecules interact with the electronegative oxygen atoms of the oxyethylene (OE) units of TX-100 through hydrogen-bonding interactions, and the electronegative oxygen atoms of the water molecules attract the electropositive imidazolium rings of [bmim][BF4]. Hence, the water molecules are like a glue that stick the IL and OE units more tightly together and thus make the microemulsion system more stable. Considering the unique solubilization behavior of added water molecules, the IL/O microemulsion system may be used as a medium to prepare porous or hollow nanomaterials by hydrolysis reactions.

  19. Role of solubilized water in the reverse ionic liquid microemulsion of 1-butyl-3-methylimidazolium tetrafluoroborate/TX-100/benzene.

    PubMed

    Gao, Yan'an; Li, Na; Zheng, Liqiang; Bai, Xiangtao; Yu, Li; Zhao, Xueyan; Zhang, Jin; Zhao, Mingwei; Li, Zhen

    2007-03-15

    The ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF4) can form nonaqueous microemulsions with benzene by the aid of nonionic surfactant TX-100. The effect of water on ionic liquid-in-oil (IL/O) microemulsions was studied, and it was shown that the addition of small amount of water to the IL microemulsion contributed to the stability of microemulsion and thus increased the amount of solubilized bmimBF4 in the microemulsion. The conductivity measurements also showed that the attractive interactions between IL microdroplets were weakened, that is, the IL/O microemulsion becomes more stable in the present of some water. Fourier transform IR was carried out to analyze the states of the added water, and the result showed that these water molecules mainly behaved as bound water and trapped water, indicating that the water molecules are located in the palisade layers of the IL/O microemulsion. Furthermore, 1H NMR and 19F NMR spectra suggested that the added water molecules built the hydrogen binding network of imidazolium cations and H2O, BF4- anion and H2O, and at the same time the electronegative oxygen atoms of the oxyethylene units of TX-100 and water in the palisade layers, which made the palisade layers more firm and thus increased the stability of the microemulsion. The study can help in further understanding the formation mechanism of microemulsions. In addition, the characteristic solubilization behavior of the added water can provide an aqueous interface film for hydrolysis reactions and therefore may be used as an ideal medium to prepare porous or hollow nanomaterials.

  20. Hydrogen bonding behaviors of binary systems containing the ionic liquid 1-butyl-3-methylimidazolium trifluoroacetate and water/methanol.

    PubMed

    Zhang, Qing-Guo; Wang, Nan-Nan; Wang, Shuang-Long; Yu, Zhi-Wu

    2011-09-29

    The hydrogen-bonding properties of binary systems consisting of a representative Brønsted acidic hydrophilic ionic liquid (IL) 1-butyl-3-methylimidazolium trifluoroacetate ([Bmim][CF(3)CO(2)]) and a cosolvent, water or methanol, over the entire concentration range have been investigated by methods of attenuated total reflectance infrared spectroscopy, (1)H NMR spectroscopy, and quantum chemical calculations. It has been found that the hydrogen-bonding interactions between the anion [CF(3)CO(2)](-), rather than the cation, and the cosolvent molecules are dominant at low concentration of cosolvent. The H-bond interaction site between the IL anion and water/methanol is the O atom in the -COO group, while the -CF(3) group makes a positive contribution by donating electron to the carboxylic group, forming a cooperative hydrogen-bonding system. For the cation [Bmim](+), although the C2-H is the favorable proton donor in H-bonding interactions, the water/methanol molecules form H-bonds with the alkyl C-H at low water/methanol concentration due to the stronger interaction between C2-H and [CF(3)CO(2)](-). Interestingly, we found that the interaction between methanol and the IL is stronger than that between water and the IL because the methyl group in methanol has a positive contribution to the formation of H-bonds. The following sequential order of interaction strength is established: [Bmim](+)-methanol-[CF(3)CO(2)](-) > [Bmim](+)-water-[CF(3)CO(2)](-) > [Bmim](+)-[CF(3)CO(2)](-) > [CF(3)CO(2)](-)-methanol > [CF(3)CO(2)] (-)-water > [Bmim](+)-methanol > [Bmim] (+)-water.

  1. Adsorption of TCDD with 1-butyl-3-methylimidazolium dicyanamide ionic liquid: a combined molecular dynamics simulation and quantum chemistry study.

    PubMed

    Pan, Wenxiao; Qi, Yuanyuan; Wang, Ruoxi; Han, Zhe; Zhang, Dongju; Zhan, Jinhua

    2013-04-01

    The effective abatement of flue gas emissions, especially polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), is one of the challenging issues in the field of environmental science currently. Imidazolium-based dicyanamide ionic liquids (ILs) were proposed to have potential in controlling the emissions of PCDD/Fs. However, the relevant mechanism at the molecular level still remains unclear. To address this subject, we here present a combined molecular dynamics (MD) simulation and quantum chemical (QM) study on the adsorption of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the most toxic congener among PCDD/F family, by 1-butyl-3-methylimidazolium dicyanamide IL, a representative imidazolium dicyanoamide ILs, which were demonstrated to possess high capture capability for PCDD/Fs. The MD simulation results show that TCDD molecules can be effectively adsorbed on the IL surface to form a dense layer, but cannot enter the interior of the IL. The results of QM calculations show that the adsorption of TCDDs on the IL surface occurs via intra-molecular hydrogen bond interactions. The calculated interaction energy of the anion with TCDD molecule is two times more than that of the cation, implying that the IL anion dominates the interaction with TCDD molecules, while the cation plays a secondary role. Based on the calculated results, we propose that imidazolium dicyanamide IL films/membranes may be better materials than the corresponding bulk for capturing TCDD. The present theoretical results may be helpful to designing the functional ILs which effectively capture and concentrate PCDD/F compounds.

  2. Phase equilibria study of the binary systems (1-butyl-3-methylimidazolium thiocyanate ionic liquid + organic solvent or water).

    PubMed

    Domańska, Urszula; Laskowska, M; Pobudkowska, Aneta

    2009-05-07

    (Solid + liquid) phase equilibria (SLE) for the binary systems, ionic liquid (IL) 1-butyl-3-methylimidazolium thiocyanate [BMIM][SCN] with an alcohol (1-octanol, 1-nonanol, 1-decanol, 1-undecanol, or 1-dodecanol) or water, and (liquid + liquid) phase equilibria (LLE) for the binary systems of [BMIM][SCN] with an alkane (n-hexane, n-heptane, n-octane, n-nonane, or n-decane), benzene, an alkylbenzenes (toluene or ethylbenzene), tetrahydrofuran (THF), cycloalkanes (cyclohexane or cycloheptane), or ethers (di-n-propyl ether, di-n-butyl ether, di-n-pentyl ether, n-butylmethyl ether, tert-butylmethyl ether (MTBE), or tert-butylethyl ether (ETBE)) have been determined at ambient pressure. A dynamic method was used over a broad range of mole fractions and temperatures from 250 to 430 K. In the case of systems IL + alkane, cycloalkane, or ether, the mutual immiscibility with an upper critical solution temperature (UCST) was detected, and in the systems of IL + benzene, alkylbenzene, or THF, the mutual immiscibility with a lower critical solution temperature (LCST) was observed. UV-vis spectroscopy was used to determine the very small compositions of the IL in the n-hexane (about 2 x 10(-5) IL mole fraction), benzene (about 2 x 10(-3) IL mole fraction), cyclohexane (about 2 x 10(-5) IL mole fraction), and THF (about 1.2 x 10(-2) IL mole fraction). For the binary systems containing alcohol, it was noticed that with increasing chain length of an alcohol, the solubility decreases. The basic thermal properties of the pure IL, that is, the glass-transition temperature as well as the heat capacity at the glass-transition temperature, have been measured using a differential scanning microcalorimetry technique (DSC). Decomposition of the IL was detected by the simultaneous TG/DTA experiments. Well-known UNIQUAC, Wilson, and NRTL equations have been used to correlate the experimental SLE data sets for alcohols and water. For the systems containing immiscibility gaps {IL + alkane

  3. Solvent and rotational relaxation of Coumarin-153 in a micellar solution of a room-temperature ionic liquid, 1-butyl-3-methylimidazolium octyl sulfate, in ethylammonium nitrate

    NASA Astrophysics Data System (ADS)

    Rao, Vishal Govind; Ghatak, Chiranjib; Pramanik, Rajib; Sarkar, Souravi; Sarkar, Nilmoni

    2010-10-01

    We have investigated the micelle formation by room-temperature ionic liquid (RTIL), 1-butyl-3-methylimidazolium octyl sulfate (bmimOs) with another RTIL, ethyl ammonium nitrate (EAN). In addition, the effect of micelle formation on the solvation and rotational relaxation dynamics have been observed using steady-state and picoseconds time-resolved spectroscopy. Both the solvent and rotational relaxations of Coumarin-153 are retarded in the micelle compared to that of neat EAN. The increase in average solvation time on going from neat EAN to bmimOs-EAN micelle is very small compared to the increase in solvation time on going from pure water to water containing micelle.

  4. Physical Properties of Ionic Liquids Consisting of the 1-Butyl-3-Methylimidazolium Cation with Various Anions and the Bis(trifluoromethylsulfonyl)imide Anion with Various Cations

    SciTech Connect

    Jin, Hui; O'Hare, Bernie; Dong, Jing; Arzhantsev, Sergei; Baker, Gary A; Wishart, James F.; Benesi, Alan; Maroncelli, Mark

    2008-01-01

    Physical properties of 4 room-temperature ionic liquids consisting of the 1-butyl-3-methylimidazolium cation with various perfluorinated anions and the bis(trifluoromethylsulfonyl)imide (Tf2N-) anion with 12 pyrrolidinium-, ammonium-, and hydroxyl-containing cations are reported. Electronic structure methods are used to calculate properties related to the size, shape, and dipole moment of individual ions. Experimental measurements of phase-transition temperatures, densities, refractive indices, surface tensions, solvatochromic polarities based on absorption of Nile Red, 19F chemical shifts of the Tf2N- anion, temperature-dependent viscosities, conductivities, and cation diffusion coefficients are reported. Correlations among the measured quantities as well as the use of surface tension and molar volume for estimating Hildebrand solubility parameters of ionic liquids are also discussed.

  5. Interaction between amphiphilic ionic liquid 1-butyl-3-methylimidazolium octyl sulfate and anionic polymer of sodium polystyrene sulfonate in aqueous medium

    NASA Astrophysics Data System (ADS)

    Barhoumi, Z.; Saini, M.; Amdouni, N.; Pal, A.

    2016-09-01

    The micellization of an aqueous solution of the surface active ionic liquid (SAIL), 1-butyl-3-methylimidazolium octylsufate (C4mim)(C8OSO3) and its interaction with an anionic polymer sodium polystyrene sulfonate, (NaPSS) were studied using conductimetry, tensiometry and fluorimetry. Surface tension profile shows a more dramatic increase in the value of surface tension of aqueous (C4mim)(C8OSO3) before the critical micelle concentration (cmc) of IL. The critical micelle concentration (cmc) value of this surfactant was found out from conductance measurements. The thermodynamic parameters, i.e., Gibb's free energy, enthalpy, and entropy of micellization of the IL in aqueous solution have been calculated. Behavior of fluorescence probe confirms the binding interactions between SAIL and the polyelectrolyte.

  6. Syntheses and crystal structures of two ionic liquids with halogen-bonding groups: 4,5-dibromo- and 4,5-diiodo-1-butyl-3-methylimidazolium trifluoromethanesulfonates

    NASA Astrophysics Data System (ADS)

    Mukai, Tomohiro; Nishikawa, Keiko

    2010-05-01

    We have prepared and characterized two novel Lewis acidic ionic liquids, 4,5-dibromo- and 4,5-diiodo-1-butyl-3-methylimidazolium trifluoromethanesulfonates, using differential scanning calorimetry and single-crystal X-ray analysis. The effect of the halogen species on the phase transition behaviour and the cation-anion interacting geometry was investigated. The minor difference in chemical structure strongly affects the melting point, glass transition temperature and crystal structure because of the different halogen-bonding strength and linearity between C-Br⋯O and C-I⋯O. Both the salts melt above room temperature, but the fused salts show glass-forming property and poor crystallizability.

  7. Melting and freezing behaviors of prototype ionic liquids, 1-butyl-3-methylimidazolium bromide and its chloride, studied by using a nano-Watt differential scanning calorimeter.

    PubMed

    Nishikawa, Keiko; Wang, Shaolan; Katayanagi, Hideki; Hayashi, Satoshi; Hamaguchi, Hiro-o; Koga, Yoshikata; Tozaki, Ken-ichi

    2007-05-10

    1-Butyl-3-methylimidazolium bromide ([bmim]Br) and its chloride ([bmim]Cl) are representative prototypes of ionic liquids. We investigated the melting and freezing behaviors of [bmim]Br and [bmim]Cl by using a homemade differential scanning calorimeter (DSC) with nano-Watt stability and sensitivity. The measurements were carried out at heating and cooling rates slow enough to mimic quasi-static processes. Their thermal behaviors of melting and freezing show characteristic features such as a wide pre-melting range and excessive supercooling and individual behaviors of single crystals even for the same substance. The melting temperatures of [bmim]Br and [bmim]Cl were determined from the broad DSC traces and discussed in relation to the crystal structure. We suggest that the observed characteristics are due to the dynamics of the cooperative change between gauche-trans (GT) and trans-trans (TT) conformations of the butyl group in the [bmim]+ cation.

  8. Physicochemical properties, structure, and conformations of 1-Butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide [C4mim]NTf2 ionic liquid.

    PubMed

    Blokhin, Andrey V; Paulechka, Yauheni U; Strechan, Aliaksei A; Kabo, Gennady J

    2008-04-10

    Thermodynamic properties of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C4mim]NTf2) ionic liquid have been studied by adiabatic calorimetry in the temperature range of 5 to 370 K. This compound has been found to form crystal, liquid, and glass. The temperature and enthalpy of fusion for [C(4)mim]NTf(2) have been determined to be T(fus) = 270.22 +/- 0.02 K and Delta(fus)H = 23.78 +/- 0.04 kJ.mol(-1), respectively. The heat capacity of crystalline [C(4)mim]NTf(2) in the T range of 205 to 255 K may vary by a few percent, subject to the procedure of the crystal preparation. The glass transition temperature for [C(4)mim]NTf(2) has been found to be T(g) = 181.5 +/- 0.1 K. On the basis of the results of DFT quantum chemical calculations, the experimental vibrational spectra, and the available literature data, thermodynamic properties of [C(4)mim]NTf(2) in the ideal-gas state have been calculated by the statistical thermodynamic methods. The entropy values for the gaseous compound obtained from the experimental data and the calculations are in satisfactory agreement.

  9. Adsorption of 1-butyl-3-methylimidazolium chloride ionic liquid by functional carbon microspheres from hydrothermal carbonization of cellulose.

    PubMed

    Qi, Xinhua; Li, Luyang; Tan, Tengfei; Chen, Wenting; Smith, Richard L

    2013-03-19

    Functional carbonaceous material (FCM) loaded with carboxylic groups was prepared by hydrothermal carbonization of cellulose in the presence of acrylic acid. The resulting FCM was used as adsorbent for recovery of a water-soluble ionic liquid, 1-butyl-3-methyl-imidazolium chloride ([BMIM][Cl]). The FCM consisted of microspheres (100-150 nm) and had a low surface area (ca. 20 m(2)/g), but exhibited adsorption capacity comparable to that of commercial activated carbon which can be attributed to the presence of high content of polar oxygenated groups (-OH, -C═O, -COOH) as revealed by spectral analyses. Sorption of [BMIM][Cl] onto FCM adsorbent could be well-described by pseudo-second-order kinetics. Thermodynamic and adsorption isothermal analyses revealed that the adsorption process was spontaneous, exothermic, and could be described by the Freundlich adsorption model. The FCM adsorbent could be regenerated effectively and recycled for at least three times without loss of adsorption capacity. The results of this work provide a facile method for production of functional carbonaceous materials from renewable resources that can be used for treatment of aqueous streams containing small concentrations of ionic liquid, [BMIM][Cl].

  10. Interactions of 1-butyl-3-methylimidazolium carboxylate ionic liquids with glucose in water: a study of volumetric properties, viscosity, conductivity and NMR.

    PubMed

    Zhuo, Kelei; Chen, Yujuan; Chen, Jing; Bai, Guangyue; Wang, Jianji

    2011-08-28

    Extensive applications of ionic liquids (ILs) may result in their accumulation in the ecological environment and organisms. Although ILs are popularly called "green solvents", their toxicity, in fact, has been exhibited. Therefore the interaction of ILs with biomolecules is a cutting-edge research subject. Herein, the interactions of 1-butyl-3-methylimidazolium carboxylate ionic liquids ([C(4)mim][HCOO], [C(4)mim][CH(3)COO] and [C(4)mim][CH(3)CH(2)COO]) with glucose in water were studied for their volumetric properties, viscosity, conductivity and NMR spectra. Limiting apparent molar volumes (V(Φ, IL)(0)), viscosity B-coefficients, limiting molar conductivities (Λ(0)) and Walden products (Λ(0)η(0)) were evaluated for the ILs in glucose + water solutions. Volumetric interaction parameters were also obtained from the transfer volumes of the ionic liquids. The contributions of the solvent properties (B(1)) and the ionic liquid-solvent interactions (B(2)) to the B-coefficient were extracted, together with molar activation energies (Δμ(IL)(0≠)) of the ionic liquids for viscous flow of the aqueous glucose + IL solution. In addition, the (13)C and (1)H NMR spectra of methyl β-D-glucopyranoside and ILs in β-D-glucopyranoside + IL + D(2)O were studied. The NMR results show that no special and strong interactions were observed between glucopyranoside and the ILs. However, it was confirmed that the H2 on the imidazolium ring has more activity (acidity) than atoms H4 and H5. The macro-properties and their changes were also discussed in terms of the size, structure and solvation of the ILs and glucose.

  11. How the cation 1-butyl-3-methylimidazolium impacts the interaction between the entrapped water and the reverse micelle interface created with an ionic liquid-like surfactant.

    PubMed

    Lépori, Cristian M O; Correa, N Mariano; Silber, Juana J; Falcone, R Darío

    2016-01-21

    The behavior of the interfacial water entrapped in reverse micelles (RMs) formed by the ionic liquid-like surfactant 1-butyl-3-methylimidazolium 1,4-bis-2-ethylhexylsulfosuccinate (bmim-AOT) dissolved in benzene (or chlorobenzene) was investigated using noninvasive techniques such as dynamic light scattering (DLS), static light scattering (SLS), FT-IR and (1)H NMR. The DLS and SLS results reveal the formation of discrete spherical and non-interacting water droplets stabilized by the bmim-AOT surfactant. Moreover, since the droplet size increases as the W0 (W0 = [water]/[surfactant]) value increases, water interacts with the RM interface. From FT-IR and (1)H NMR data, a weaker water-surfactant interaction in bmim-AOT RMs in comparison with the RMs created by sodium 1,4-bis-2-ethylhexylsulfosuccinate (Na-AOT) is detected. Consequently, there are less water molecules interacting with the interface in bmim-AOT RMs, and their hydrogen bond network is not completely disrupted as they are in Na-AOT RMs. The results show how the nature of the new cation impacts the interaction between the entrapped water and the RM interface, modifying the interfacial water structure in comparison with the results known for Na-AOT.

  12. Thermodynamic, dynamic, and structural properties of ionic liquids comprised of 1-butyl-3-methylimidazolium cation and nitrate, azide, or dicyanamide anions.

    PubMed

    Bedrov, Dmitry; Borodin, Oleg

    2010-10-14

    Molecular dynamics simulations of ionic liquids (IL) comprised of 1-butyl-3-methylimidazolium [bmim] cation and nitrate [NO(3)], azide [N(3)], or dicyanamide [N(CN)(2)] anions were conducted using the polarizable APPLE&P force field. Comparison of thermodynamic properties such as densities, enthalpies of vaporization, and ion binding energies as well as structural correlations obtained from simulations at atmospheric pressure and temperature range 298-393 K showed that IL with the N(CN)(2) anion shows significantly different characteristics as compared to ILs with the N(3) and NO(3) anions. [bmim][N(CN)(2)] IL was found to have the lowest enthalpy of vaporization and the weakest ion-ion structural correlation as compared to ILs with the other two ions. This trend was further manifested in dynamical properties characterized by self-diffusion coefficients and molecular rotational relaxation times, where IL with the N(CN)(2) anion showed the fastest dynamics as compared to other ILs. We also examine the dynamic correlations between the ions' translational and rotational motions as well as discuss the anisotropy of the latter.

  13. Vibrational sum-frequency generation spectroscopy of ionic liquid 1-butyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate at the air-water interface

    NASA Astrophysics Data System (ADS)

    Saha, Ankur; SenGupta, Sumana; Kumar, Awadhesh; Choudhury, Sipra; Naik, Prakash D.

    2016-08-01

    The structure and orientation of room temperature ionic liquid (RTIL) 1-butyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate [PF3(C2F5)3], commonly known as [bmim][fap], have been investigated at the air-[bmim][fap] and air-water interfaces, employing vibrational sum-frequency generation (VSFG) spectroscopy. The VSFG spectra in the CH stretch region suggest presence of the [bmim] cation at the interfaces. Studies reveal that the butyl chain protrudes out into air, and the imidazolium ring lies almost planar to the interface. The CH stretch intensities get enhanced at the air-water interface, mainly because of polar orientation of imidazolium cation induced by interfacial water molecules. The OH stretch intensities are also enhanced at the air-water interface due to polar orientation of interfacial water molecules induced by [bmim][fap]. The Brewster angle microscopy suggests self aggregation of [bmim][fap] in the presence of water, and the aggregation becomes extensive showing dense surface domains with time. However, the surface pressure is almost unaffected due to aggregation.

  14. Electrochemical and Thermodynamic Properties of Ln(III) (Ln = Eu, Sm, Dy, Nd) in 1-Butyl-3-Methylimidazolium Bromide Ionic Liquid

    PubMed Central

    Yang, Xiao; He, Ling; Qin, Song; Tao, Guo-Hong; Huang, Ming; Lv, Yi

    2014-01-01

    The electrochemical behavior and thermodynamic properties of Ln(III) (Ln = Eu, Sm, Dy, Nd) were studied in 1-butyl-3-methylimidazolium bromide ionic liquid (BmimBr) at a glassy carbon (GC) electrode in the range of 293–338 K. The electrode reaction of Eu(III) was found to be quasi-reversible by the cyclic voltammetry, the reactions of the other three lanthanide ions were regarded as irreversible systems. An increase of the current intensity was obtained with the temperature increase. At 293 K, the cathodic peak potentials of −0.893 V (Eu(III)), −0.596 V (Sm(III)), −0.637 V (Dy(III)) and −0.641 V (Nd(III)) were found, respectively, to be assigned to the reduction of Ln(III) to Ln(II). The diffusion coefficients (Do), the transfer coefficients (α) of Ln(III) (Ln = Eu, Sm, Dy, Nd) and the charge transfer rate constants (ks) of Eu(III) were estimated. The apparent standard potential (E0*) and the thermodynamic properties of the reduction of Eu(III) to Eu(II) were also investigated. PMID:24752584

  15. Conductivity and spectroscopic investigation of bis(trifluoromethanesulfonyl)imide solution in ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide.

    PubMed

    Yu, Lei; Pizio, Benjamin S; Vaden, Timothy D

    2012-06-07

    Protic ionic liquids (PILs) are promising alternatives to water for swelling Nafion as a fuel cell proton exchange membrane (PEM). PILs can significantly improve the high-temperature performance of a PEM. The proton dissociation and solvation mechanisms in a PIL, which are keys to understanding the proton transportation and conductivity, have not been fully explored. In this paper, we used FTIR, Raman, and electronic spectroscopy with computational simulation techniques to explore the spectroscopic properties of bis(trifluoromethanesulfonyl)imide (HTFSI) solutions in 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (BMITFSI) ionic liquid at concentrations from ∼0.1 to as high as ∼1.0 M. Solution conductivities were measured at room temperature and elevated temperatures up to ∼65 °C. The solution structure and properties depend on the concentration of HTFSI. At lower concentration, around 0.1 M, the HTFSI solution has higher conductivity than pure BMITFSI. However, the conductivity decreases when the concentration increases from 0.1 to 1.0 M. Temperature-dependent conductivities followed the Vogel-Fulcher-Tamman equation at all concentrations. Conductivity and spectroscopy results elucidate the complicated ionization and solvation mechanism of HTFSI in BMITFSI solutions. Raman spectroscopy and density functional theory (DFT) calculations are consistent with the complete ionization of HTFSI to generate solvated H(+) at low concentrations. FTIR, Raman, and electronic spectroscopic results as well as DFT computational simulation indicated that when the concentration is as high as 1.0 M, a significant amount of TFSI(-) is protonated, most likely at the imide nitrogen.

  16. Characterization of the influence of the ionic liquid 1-butyl-3-methylimidazolium chloride on the structure and thermal stability of green fluorescent protein.

    PubMed

    Heller, William T; O'Neill, Hugh M; Zhang, Qiu; Baker, Gary A

    2010-11-04

    Ionic liquids (ILs) are finding a vast array of applications as novel solvents for a wide variety of processes that include enzymatic chemistry, particularly as more biocompatible ILs are designed and discovered. While it is assumed that a native or near-native structure is required for enzymatic activity, there is some evidence that ILs alter protein structure and oligomerization states in a manner than can negatively impact function. The IL 1-butyl-3-methylimidazolium chloride, [bmim]Cl, is a well-studied, water-miscible member of the popular 1-alkyl-3-methylimidazolium IL family. To improve our understanding of the impact of water-miscible ILs on proteins, we have characterized the structure and oligomerization state of green fluorescent protein (GFP) in aqueous solutions containing 25 and 50 vol % [bmim]Cl using a combination of optical spectroscopy and small-angle neutron scattering (SANS). Measurements were also performed as a function of temperature to provide insight into the effect of the IL on the thermal stability of GFP. While GFP exists as a dimer in water, the presence of 25 vol % [bmim]Cl causes GFP to transition to a monomeric state. The SANS data indicate that GFP is a great deal less compact in 50 vol % [bmim]Cl than in neat water, indicative of unfolding from the native structure. The oligomerization state of the protein in IL-containing aqueous solution changes from a dimer to a monomer in response to the IL, but does not change as a function of temperature in the IL-containing solution. The SANS and spectroscopic results also demonstrate that the addition of [bmim]Cl to the solution decreases the thermal stability of GFP, allowing the protein to unfold at lower temperatures than in aqueous solution.

  17. Electrochemical and spectral properties of ferrocene (Fc) in ionic liquid: 1-butyl-3-methylimidazolium triflimide, [BMIM][NTf(2)]. Concentration effects.

    PubMed

    Vorotyntsev, Mikhail A; Zinovyeva, Veronika A; Konev, Dmitry V; Picquet, Michel; Gaillon, Laurent; Rizzi, Cecile

    2009-01-29

    Several earlier studies of the electrochemical oxidation of ferrocene (Fc) in room-temperature ionic liquids revealed an essentially nonlinear dependence of the oxidation current on the Fc concentration in its relatively dilute solutions, with its formally calculated diffusion coefficient strongly increasing with the concentration. Since no plausible mechanism leading to this very unusual finding had been proposed, our study of Fc solutions in 1-butyl-3-methylimidazolium triflimide, [BMIM][NTf(2)], was performed to verify whether the above observation originated from an incorrect determination of the dissolved Fc concentration. Our observations have demonstrated that reliable control of the Fc concentration in solution is complicated by factors such as the low amount of Fc used to prepare small-volume solutions or the great difficulty to dissolve completely a solid powder in a solvent with an extremely high viscosity. An unexpected additional complication is related to a sufficiently high volatility of Fc which manifests itself even at room temperature and especially at elevated temperatures or/and in the course of vacuum treatment of its solutions or its solid powder. Parallel measurements of electrochemical responses and UV-visible spectra for several series of Fc solutions of various concentrations (prepared with the use of different procedures) have shown a perfect parallelism between the peak current and the intensity of the absorption band in the range of 360-550 nm, leading us to the conclusion of a linear relationship between the oxidation current and the molecularly dissolved Fc concentration. The relations of these measured characteristics with the estimated Fc concentration in these solutions have demonstrated a much greater dispersion (attributed to the difficulty of a precise measurement of the latter) but without a significant deviation from the linearity in general. This finding has allowed us to estimate the diffusion coefficient of this species: D

  18. Asymmetric criticality of binary ionic solutions containing 1-butyl-3-methylimidazolium tetrafluoroborate and alcohol.

    PubMed

    Yin, Tianxiang; Xu, Chen; Lv, Hekun; Liu, Shixia; Wang, Mingjie; Chen, Zhiyun; Shen, Weiguo

    2014-09-07

    The liquid-liquid coexistence curves for binary solutions {1-butyl-3-methylimidazolium tetrafluoroborate ([C4mim][BF4]) + 1-propanol} and {1-butyl-3-methylimidazolium tetrafluoroborate ([C4mim][BF4]) + 2-propanol} have been precisely measured. The values of the critical exponents β obtained from the liquid-liquid equilibrium data in the critical region confirmed the 3D-Ising universality. The isobaric heat capacities per unit volume were measured for {[C4mim][BF4] + 1-propanol (or 2-propanol, 1,3-propanediol, 1,4-butanediol)} in both critical and non-critical regions. The experimental results indicate a major solvophobic contribution to the criticality for the studied ionic solutions. The complete scaling theory was applied to well represent the asymmetric behavior of the diameter of the coexistence curves with the consideration of the heat capacity contribution. It was found that the contribution of the heat capacity related term in the ionic solution decreased with the increase of the permittivity of alcohol and was more important in the description of the asymmetry of the coexistence curve of the ionic solutions than that of the molecular solutions.

  19. Electrochemical reduction of aromatic ketones in 1-butyl-3-methylimidazolium-based ionic liquids in the presence of carbon dioxide: the influence of the ketone substituent and the ionic liquid anion on bulk electrolysis product distribution.

    PubMed

    Zhao, Shu-Feng; Horne, Mike; Bond, Alan M; Zhang, Jie

    2015-07-15

    Electrochemical reduction of aromatic ketones, including acetophenone, benzophenone and 4-phenylbenzophenone, has been undertaken in 1-butyl-3-methylimidazolium-based ionic liquids containing tetrafluoroborate ([BF4](-)), trifluoromethanesulfonate ([TfO](-)) and tris(pentafluoroethyl)trifluorophosphate ([FAP](-)) anions in the presence of carbon dioxide in order to investigate the ketone substituent effect and the influence of the acidic proton on the imidazolium cation (C2-H) on bulk electrolysis product distribution. For acetophenone, the minor products were dimers (<10%) in all ionic liquids, which are the result of acetophenone radical anion coupling. For benzophenone and 4-phenylbenzophenone, no dimers were formed due to steric hindrance. In these cases, even though carboxylic acids were obtained, the main products generated were alcohols (>50%) derived from proton coupled electron transfer reactions involving the electrogenerated radical anions and C2-H. In the cases of both acetophenone and benzophenone, the product distribution is essentially independent of the ionic liquid anion. By contrast, 4-phenylbenzophenone shows a product distribution that is dependent on the ionic liquid anion. Higher yields of carboxylic acids (∼40%) are obtained with [TfO](-) and [FAP](-) anions because in these ionic liquids the C2-H is less acidic, making the formation of alcohol less favourable. In comparison with benzophenone, a higher yield of carboxylic acid (>30% versus ∼15%) was obtained with 4-phenylbenzophenone in all ionic liquids due to the weaker basicity of 4-phenylbenzophenone radical anion.

  20. New solvents designed on the basis of the molecular-microscopic properties of binary mixtures of the type (protic molecular solvent + 1-butyl-3-methylimidazolium-based ionic liquid).

    PubMed

    Fortunato, Graciela G; Mancini, Pedro M; Bravo, M Virginia; Adam, Claudia G

    2010-09-16

    The main purpose of this work is to analyze the microscopic feature of solvent systems resulting from the basis of binary mixtures formed by a protic molecular solvent (methanol, ethanol, propan-1-ol, propan-2-ol, and 2-ethoxyethanol) and a 1-butyl-3-methylimidazolium (bmim)-based ionic liquid (IL) cosolvent composed of different anions (tetrafluoroborate, hexafluorophosphate, chloride, and bromide). At the same time, a complementary aim is to evaluate the incidence of anion type on the solvation pattern. The empirical solvatochromic parameters E(T)(N), π*, β, and α were determined from the UV-vis solvatochromic shifts of adequate probes. The behavior of the solvent systems was analyzed according to their deviation from ideality. E(T)(N) polarity and π* dipolarity/polarizability exhibit positive deviation from ideal behavior in all binary mixtures at the explored compositions. Moreover, E(T)(N) and α parameters display synergetic effects in some binary mixtures composed of tetrafluoroborate and hexafluorophosphate anions. The influence of anion nature on the response patterns is clearly manifested in the basicity β and acidity α of the media. This is connected with the degree and type of interaction between the anions and the 1-butyl-3-methylimidazolium cation. The ion-pair character of the ionic liquids affects their interactions with a solute or a molecular solvent. The application of an appropriate preferential solvation model allowed us to obtain valuable information about solute-solvent and solvent-solvent interactions of the selected ionic liquid mixtures. It is possible to identify relevant mixtures paying particular attention to the most remarkable microscopic properties, the acidity and the basicity, in order to propose "new solvents". Thus, the solvating feature can be tailored selecting the molecular and/or the ionic component at a particular composition. A simplified combined nearly ideal binary solvent/Redlich-Kister (CNIBS/R-K) equation is

  1. The effect of different interfaces and confinement on the structure of the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide entrapped in cationic and anionic reverse micelles.

    PubMed

    Ferreyra, Darío D; Correa, N Mariano; Silber, Juana J; Falcone, R Darío

    2012-03-14

    The behavior of the ionic liquid (IL) 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([bmim][Tf(2)N]) entrapped in two reverse micelles (RMs) formed in an aromatic solvent as dispersant pseudophase: [bmim][Tf(2)N]/benzyl-n-hexadecyldimethylammonium chloride (BHDC)/chlorobenzene and [bmim][Tf(2)N]/sodium 1,4-bis-2-ethylhexylsulfosuccinate (AOT)/chlorobenzene, was investigated using dynamic light scattering (DLS), FT-IR and (1)H NMR spectroscopies. DLS results reveal the formation of RMs containing [bmim][Tf(2)N] as a polar component since the droplet size values increase as the W(s) (W(s) = [[bmim][Tf(2)N

  2. Replica-exchange molecular dynamics simulations of cellulose solvated in water and in the ionic liquid 1-butyl-3-methylimidazolium chloride

    SciTech Connect

    Mostofian, Barmak; Cheng, Xiaolin; Smith, Jeremy C.

    2014-09-02

    Ionic liquids have become a popular solvent for cellulose pretreatment in biorefineries due to their efficiency in dissolution and their reusability. Understanding the interactions between cations, anions, and cellulose is key to the development of better solvents and the improvement of pretreatment conditions. While previous studies described the interactions between ionic liquids and cellulose fibers, shedding light on the initial stages of the cellulose dissolution process, we study the end state of that process by exploring the structure and dynamics of a single cellulose decamer solvated in 1-butyl-3-methyl-imidazolium chloride (BmimCl) and in water using replica-exchange molecular dynamics. In both solvents, global structural features of the cellulose chain are similar. However, analyses of local structural properties show that cellulose explores greater conformational variability in the ionic liquid than in water. For instance, in BmimCl the cellulose intramolecular hydrogen bond O3H'••• O5 is disrupted more often resulting in greater flexibility of the solute. Our results indicate that the cellulose chain is more dynamic in BmimCl than in water, which may play a role in the favorable dissolution of cellulose in the ionic liquid. Here, the calculation of the configurational entropy of the cellulose decamer confirms its higher conformational flexibility in BmimCl than in water at elevated temperatures.

  3. Dynamics of solvent and rotational relaxation of coumarin 153 in room-temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate confined in Brij-35 micelles: a picosecond time-resolved fluorescence spectroscopic study.

    PubMed

    Chakraborty, Anjan; Seth, Debabrata; Chakrabarty, Debdeep; Setua, Palash; Sarkar, Nilmoni

    2005-12-15

    The dynamics of solvent and rotational relaxation of Coumarin 153 (C-153) in ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) and in the ionic liquid confined in Brij-35 micellar aggregates have been investigated using steady-state and time-resolved fluorescence spectroscopy. We observed slower dynamics in the presence of micellar aggregates as compared to the pure IL. However, the slowing down in the solvation time on going from neat IL to IL-confined micelles is much smaller compared to that on going from water to water-confined micellar aggregates. The increase in solvation and rotational time in micelles is attributed to the increase in viscosity of the medium. The slow component is assumed to be dependent on the viscosity of the solution and involves large-scale rearrangement of the anions and cations while fast component is assumed to originate from the initial response of the anions during excitation. The slow component increases due to the increase in the viscosity of the medium and increase in fast component is probably due to the hydrogen bonding between the anions and polar headgroup of the surfactant. The dynamics of solvent relaxation was affected to a small extent due to the micelle formation.

  4. Synthesis, characterization, and application of 1-butyl-3-methylimidazolium thiocyanate for extractive desulfurization of liquid fuel.

    PubMed

    Dharaskar, Swapnil A; Wasewar, Kailas L; Varma, Mahesh N; Shende, Diwakar Z

    2016-05-01

    1-Butyl-3-methylimidazolium thiocyanate [BMIM]SCN has been presented on extractive desulfurization of liquid fuel. The FTIR, (1)H-NMR, and C-NMR have been discussed for the molecular confirmation of synthesized [BMIM]SCN. Further, thermal, conductivity, moisture content, viscosity, and solubility analyses of [BMIM]SCN were carried out. The effects of time, temperature, sulfur compounds, ultrasonication, and recycling of [BMIM]SCN on removal of dibenzothiophene from liquid fuel were also investigated. In extractive desulfurization, removal of dibenzothiophene in n-dodecane was 86.5 % for mass ratio of 1:1 in 30 min at 30 °C under the mild process conditions. [BMIM]SCN could be reused five times without a significant decrease in activity. Also, in the desulfurization of real fuels, multistage extraction was examined. The data and results provided in the present paper explore the significant insights of imidazolium-based ionic liquids as novel extractant for extractive desulfurization of liquid fuels.

  5. (BMI)3LnCl6 crystals as models for the coordination environment of LnCl3 (Ln = Sm, Eu, Dy, Er, Yb) in 1-butyl-3-methylimidazolium chloride ionic-liquid solution.

    PubMed

    Han, Yulun; Lin, Cuikun; Meng, Qingguo; Dai, Fengrong; Sykes, Andrew G; Berry, Mary T; May, P Stanley

    2014-06-02

    A series of (BMI)3LnCl6 (Ln = Sm, Eu, Dy, Er, Yb) crystals was prepared from solutions of LnCl3 dissolved in the ionic liquid, 1-butyl-3-methylimidazolium chloride (BMICl). Crystals with Ln = 5% Sm + 95% Gd and with Ln = 5% Dy + 95% Gd were also grown to assess the importance of cross-relaxation in the Sm and Dy samples. The crystals are isostructural, with monoclinic space group P21/c and four formula units per unit cell. The first coordination sphere of Ln(3+) consists of six Cl(-) anions forming a slightly distorted octahedral LnCl6(3-) center. The second coordination sphere is composed of nine BMI(+) cations. The emission spectra and luminescence lifetimes of both (BMI)3LnCl6 crystals and LnCl3 in BMICl solution were measured. The spectroscopic similarities suggest that crystalline (BMI)3LnCl6 provides a good model of the Ln(3+) coordination environment in BMICl solution.

  6. Solvent and rotational relaxation of coumarin-153 and coumarin-480 in ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate) modified sodium 1,4-bis(2-ethylhexyl) sulfosuccinate (NaAOT) micelle

    NASA Astrophysics Data System (ADS)

    Rao, Vishal Govind; Banerjee, Chiranjib; Mandal, Sarthak; Ghosh, Surajit; Sarkar, Nilmoni

    2013-02-01

    Understanding ion transport dynamics, structure of surfactant aggregates in ionic liquids or ionic liquid/water solutions are quite interesting and potentially important due to widespread applications of surfactant-based systems. In this manuscript we have investigated the effect of 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF4) addition on solvent and rotational relaxation of coumarin-153 (C-153) and coumarin-480 (C-480) in aqueous solution of sodium 1,4-bis(2-ethylhexyl) sulfosuccinate (NaAOT) using steady state and picosecond time resolved fluorescence spectroscopy. The strong adsorption of the bmim+ at the interface and the role of the ionic liquid particularly the cation bmim+ in the modification of the interfacial geometry were probed by the analysis of decay parameters and the rotational relaxation parameters. Since the addition of the NaAOT in water-bmimBF4 mixture above critical micellar concentration (48 mM, obtained from observing pyrene fluorescence) causes strong adsorption of the ionic liquid particularly the cation bmim+, the average solvation time, particularly the slow component increases significantly. More importantly we have found the probe dependent solvation dynamics due to the different location of the probe molecules, C-153 and C-480. C-153 being hydrophobic in nature resides in the stern layer and the adsorption of the bmim+ at the interface modifies stern layer more effectively. So we have observed more pronounced change in solvation dynamics in case of C-153 compared to that in case of C-480. The fluorescence anisotropy decays of the probe molecules were found to be biexponential in nature. The anisotropy decay was interpreted by using a model which consists of the wobbling (rotational) and translational diffusion of the dye coupled with the rotational motion of the micelle as a whole.

  7. Interaction of ionic liquid with water in ternary microemulsions (Triton X-100/water/1-butyl-3-methylimidazolium hexafluorophosphate) probed by solvent and rotational relaxation of coumarin 153 and coumarin 151.

    PubMed

    Seth, Debabrata; Chakraborty, Anjan; Setua, Palash; Sarkar, Nilmoni

    2006-08-29

    The interaction of ionic liquid with water in 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6])/Triton X-100 (TX-100)/H2O ternary microemulsions, i.e., "[bmim][PF6]-in-water" microregions of the microemulsions, has been studied by the dynamics of solvent and rotational relaxation of coumarin 153 (C-153) and coumarin 151 (C-151). The variation of the time constants of solvent relaxation of C-153 is very small with an increase in the [bmim][PF6]/TX-100 ratio (R). The rotational relaxation time of C-153 also remains unchanged in all micremulsions of different R values. The invariance of solvation and rotational relaxation times of C-153 indicates that the position of C-153 remains unaltered with an increase in R and probably the probe is located at the interfacial region of [bmim][PF6] and TX-100 in the microemulsions. On the other hand, in the case of C-151, with an increase in R the fast component of the solvation time gradually increases and the slow component gradually decreases, although the change in solvation time is small in comparison to that of microemulsions containing common polar solvents such as water, methanol, acetonitrile, etc. The rotational relaxation time of C-151 increases with an increase in R. This indicates that with an increase in the [bmim][PF6] content the number of C-151 molecules in the core of the microemulsions gradually increases. In general, the solvent relaxation time is retarded in this room temperature ionic liquid/water-containing microemulsion compared to that of a neat solvent, although retardation is very small compared to that of the solvent relaxation time of the conventional solvent in the core of the microemulsions.

  8. Synthesis, characterization and application of 1-butyl-3 methylimidazolium chloride as green material for extractive desulfurization of liquid fuel.

    PubMed

    Dharaskar, Swapnil A; Varma, Mahesh N; Shende, Diwakar Z; Yoo, Chang Kyoo; Wasewar, Kailas L

    2013-01-01

    The possible application of imidazolium ionic liquids as energy-efficient green material for extractive deep desulfurization of liquid fuel has been investigated. 1-Butyl-3-methylimidazolium chloride [BMIM]Cl was synthesized by nucleophilic substitution reaction of n-methylimidazolium and 1-chlorobutane. Molecular structures of the ILs were confirmed by FTIR, (1)H-NMR, and (13)C-NMR. The thermal properties, conductivity, solubility, water content and viscosity analysis of [BMIM]Cl were carried out. The effects of reaction time, reaction temperature, sulfur compounds, and recycling of IL without regeneration on dibenzothiophene removal of liquid fuel were presented. In the extractive desulfurization process, the removal of dibenzothiophene in n-dodecane using [BMIM]Cl was 81% with mass ratio of 1 : 1, in 30 min at 30°C under the mild reaction conditions. Also, desulfurization of real fuels with IL and multistage extraction were studied. The results of this work might offer significant insights in the perceptive use of imidazoled ILs as energy-efficient green material for extractive deep desulfurization of liquid fuels as it can be reused without regeneration with considerable extraction efficiency.

  9. Synthesis, Characterization and Application of 1-Butyl-3 Methylimidazolium Chloride as Green Material for Extractive Desulfurization of Liquid Fuel

    PubMed Central

    Dharaskar, Swapnil A.; Varma, Mahesh N.; Shende, Diwakar Z.; Yoo, Chang Kyoo; Wasewar, Kailas L.

    2013-01-01

    The possible application of imidazolium ionic liquids as energy-efficient green material for extractive deep desulfurization of liquid fuel has been investigated. 1-Butyl-3-methylimidazolium chloride [BMIM]Cl was synthesized by nucleophilic substitution reaction of n-methylimidazolium and 1-chlorobutane. Molecular structures of the ILs were confirmed by FTIR, 1H-NMR, and 13C-NMR. The thermal properties, conductivity, solubility, water content and viscosity analysis of [BMIM]Cl were carried out. The effects of reaction time, reaction temperature, sulfur compounds, and recycling of IL without regeneration on dibenzothiophene removal of liquid fuel were presented. In the extractive desulfurization process, the removal of dibenzothiophene in n-dodecane using [BMIM]Cl was 81% with mass ratio of 1 : 1, in 30 min at 30°C under the mild reaction conditions. Also, desulfurization of real fuels with IL and multistage extraction were studied. The results of this work might offer significant insights in the perceptive use of imidazoled ILs as energy-efficient green material for extractive deep desulfurization of liquid fuels as it can be reused without regeneration with considerable extraction efficiency. PMID:24307868

  10. Ultrasound-promoted catalyst-free one-pot four component synthesis of 2H-indazolo[2,1-b]phthalazine-triones in neutral ionic liquid 1-butyl-3-methylimidazolium bromide.

    PubMed

    Shekouhy, Mohsen; Hasaninejad, Alireza

    2012-03-01

    A catalyst-free one-pot four component methodology for the synthesis of 2H-indazolo[2,1-b]phthalazine-triones under ultrasonic irradiation at room temperature using 1-butyl-3-methylimidazolium bromide, [Bmim]Br, as a neutral reaction medium is described. A broad range of structurally diverse aldehydes (aromatic aldehydes bearing electron withdrawing and/or electron releasing groups as well as heteroaromatic aldehydes) were applied successfully, and corresponding products were obtained in good to excellent yields without any byproduct.

  11. Simultaneous separation of basic and acidic proteins using 1-butyl-3-methylimidazolium-based ion liquid as dynamic coating and background electrolyte in capillary electrophoresis.

    PubMed

    Wu, Xiaoping; Wei, Weiping; Su, Qingmei; Xu, Liangjun; Chen, Guonan

    2008-06-01

    1-Butyl-3-methylimidazolium tetrafluoroborate ionic liquids (1B-3MI-TFB ILs) were employed as a coating material and BGE in CE for simultaneous separation of basic and acidic proteins such as lysozyme, cytochrome C, ribonuclease A, albumin, and alpha-lactalbumin. 1B-3MI-TFB ILs effectively reversed the surface charges on the capillary inner surface, preventing the adsorption of positively charged proteins onto the silica surface, as well as associated with proteins, thus benefiting the separation efficiencies and reproducibility. Consequently, simultaneous baseline separation of five proteins was achieved within 14 min by using 10 mM of 1B-3MI-TFB ILs as dynamic coating and the only running electrolyte at the voltage of +20 kV. The proposed coating technique is simple, less time-consuming, reproducible, and also stable enough for proteins separation without the need of additives. Symmetrical peaks with efficiencies up to 670,000 plates/m were obtained. Recoveries of proteins with RSD (for migration times) of 0.23-0.42% (run-to-run) and 2.5-3.8% (day-to-day) were achieved, respectively. The applicability of the proposed method in proteins separation was evaluated by the separation of egg white samples.

  12. TX-100/water/1-butyl-3-methylimidazolium hexafluorophosphate microemulsions.

    PubMed

    Gao, Yanan; Han, Shuaibing; Han, Buxing; Li, Ganzuo; Shen, Dong; Li, Zhonghao; Du, Jimin; Hou, Wanguo; Zhang, Gaoyong

    2005-06-21

    Both ionic liquids and water are typical green solvents. In this work, the phase behavior of the ternary system consisting of ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF6), TX-100, and water was determined at 25.0 degrees C. The water-in-bmimPF6, bicontinuous, and bmimPF6-in-water microregions of the microemulsions were identified by cyclic voltammetry method using potassium ferrocyanide K4Fe(CN)6 as the electroactive probe. Dynamic light scattering (DLS) and the UV-vis method were used to characterize the microemulsions. It was demonstrated that the hydrodynamic diameter (Dh) of the bmimPF6-in-water microemulsions is nearly independent of the water content but increases with increasing bmimPF6 content due to the swelling of the micelles by the ionic liquid. The UV-vis further confirmed the existence of water domains in the water-in-bmimPF6 microemulsions, and the salt potassium ferricyanide K3Fe(CN)6 could be dissolved in the water domains.

  13. Benzene and cyclohexane separation using 1-butyl-3-methylimidazolium thiocyanate

    NASA Astrophysics Data System (ADS)

    Gonfa, Girma; Ismail, Marhaina; Bustam, Mohamad Azmi

    2017-09-01

    Cyclohexane is mainly produced by catalytic hydrogenation of benzene. Removal of unreacted benzene from the product stream is very important in this process. However, due to their close boiling points and azeotrope formation, it is very difficult to separate cyclohexane and benzene by conventional distillation. Currently, special separation processes such as processes extractive distillation is commercially used for this separation. However, this extractive distillation suffers from process complexity and higher energy consumption due to their low extractive selectivity of molecular entrainers used. The aim of the present work is to investigate the applicability of ionic liquids as entrainer in extractive distillation of benzene and cyclohexane mixture. In this study, we investigated 1-butyl-3-methylimidazolium thiocyanate ([BMIM][SCN]) ionic liquid for separation of benzene and cyclohexane by measuring the Vapor Liquid Equilibrium data of the two components in the presence of the ionic liquid. As green and potential environmentally friendly solvents, ionic liquids have attracted increasing attention as alternative conventional entrainers in extractive distillation. Isothermal Vapor Liquid Equilibrium for the benzene + cyclohexane + [BMIM][SCN] ternary system was obtained at 353.15 K using a Head Space Gas Chromatography. The addition of [BMIM][SCN] breaks the benzene-cyclohexane azeotrope and increased the relative volatility cyclohexane to benzene in the mixture. The effect of [BMIM][SCN] on the relative volatility cyclohexane to benzene was studied at various benzene and cyclohexane compositions and solvent to feed ratios. The performance of [BMIM][SCN] was compared with typical conventional solvents, dimethylformamide (DMF) and dimethylsulfoxide (DMSO). The results show that the relative volatility of cyclohexane to benzene in the presence of [BMIM][SCN] is higher compared that of DMSO and DMF.

  14. Acute toxicity, biochemical toxicity and genotoxicity caused by 1-butyl-3-methylimidazolium chloride and 1-butyl-3-methylimidazolium tetrafluoroborate in zebrafish (Danio rerio) livers.

    PubMed

    Zhang, Cheng; Shao, Yuting; Zhu, Lusheng; Wang, Jinhua; Wang, Jun; Guo, Yingying

    2017-02-21

    The present study examined the potential toxicity of 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) and 1-butyl-3- methylimidazolium tetrafluoroborate ([Bmim]BF4) in the liver cells of zebrafish (Danio rerio) with different doses (20-160mg/L) on 7 and 14days. The effects of [Bmim]Cl and [Bmim]BF4 on acute toxicity, reactive oxygen species (ROS), antioxidant enzymes, glutathione S-transferase (GST), malondialdehyde (MDA), and DNA damage degree in livers of zebrafish were determined. The 50% lethal concentration (LC50) values after a 96-h exposure to [Bmim]Cl and [Bmim]BF4 were 632.8±67.4 and 604.6±56.2mg/L, respectively, which indicated that the substances were practically harmless. The minor discrepancy may be caused by the different anions. The ROS levels were dose-dependent, which may cause the inhibition of antioxidant enzyme activity, lipid peroxidation, DNA damage and the stimulation of detoxifying enzyme activity. The present study can also provide scientific support for the future selection and evaluation of ionic liquids (ILs).

  15. ALPHA-AMYLASE ACTIVITY IN VARIOUS CONCENTRATIONS OF THE IONIC LIQUID, 1-BUTYL-3-METHYLIMIDAZOLIUM CHLORIDE

    USDA-ARS?s Scientific Manuscript database

    Starch is an extremely abundant, economical and versatile industrial commodity. Many industrial uses of starch depend on hydrolyzing the polymer for the conversion of glucose and maltodextrins. Starch hydrolysis is frequently achieved by utilizing alpha-amylase, which is an endo-acting enzyme that...

  16. Green polymer electrolytes based on chitosan and 1-butyl-3-methylimidazolium acetate

    SciTech Connect

    Shamsudin, Intan Juliana; Ahmad, Azizan; Hassan, Nur Hasyareeda

    2014-09-03

    Green polymer electrolytes based on chitosan as the polymer matrix and ionic liquid 1-butyl-3-methylimidazolium acetate [Bmim][OAc] as charge carriers were prepared by solution casting technique. Complexes with various amount of ionic liquid loading were investigated as possible ionic conducting polymers. The ionic conductivity was found to increase with increasing weight percent of ionic liquid. The highest ionic conductivity of the charged chitosan-[Bmim][OAc] was 2.44 × 10{sup −3} S cm{sup −1} at 90 wt.% of [Bmim][OAc] content at ambient temperature. Attenuated Total Reflection Fourier Transform infrared (ATR-FTIR) spectroscopy has proven the interaction between chitosan and [Bmim][OAc]. X-ray Diffraction (XRD) has shown that the amorphosity of the complexes increase as the amount of [Bmim][OAc] increase.

  17. Reactions of Starch in Ionic Liquids

    USDA-ARS?s Scientific Manuscript database

    We found that starches are found to be soluble at 80 ºC in ionic liquids such as 1-butyl-3-methylimidazolium chloride (BMIMCl) and 1-butyl-3-methylimidazolium dicyanamide (BMIMdca) in concentration up to 10% (w/w). Higher concentrations of biopolymers in these novel solvents resulted in solutions w...

  18. Polymer electrolyte based on crosslinked poly(glycidyl methacrylate) and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide

    SciTech Connect

    Fei, Beatrice Wong Chui; Hanifah, Sharina Abu; Ahmad, Azizan; Hassan, Nur Hasyareeda

    2015-09-25

    Polymer electrolytes based on crosslinked poly(glycidyl methacrylate) as polymer host and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BmimTFSI) as incorporated salt were prepared by in-situ photopolymerization technique. The complexes with different mass ratio of glycidyl methacrylate (GMA) monomer to BmimTFSI were investigated. The ionic conductivity of the polymer electrolyte was increased and reach the highest value of 7.50 × 10{sup −4} S cm{sup −1} at the ratio of 3:7 (GMA: BmimTFSI). The interaction between the polymer host and ionic liquid was proved by Attenuated Total Reflectance-Fourier Transformation Infra-Red Spectroscopy (ATR-FTIR). Meanwhile, the X-ray diffraction analysis shows the amorphousity of the polymer electrolyte film increase with the ionic liquid ratio.

  19. Functionalization and Passivation of Boron Nanoparticles with a Hypergolic Ionic Liquid (Pre-Print)

    DTIC Science & Technology

    2012-04-01

    measured a heat of combustion of 30.6 kJ/g (32.44 kJ/mL) for 1-butyl-3-methylimidazolium dicyanamide ([BMIM][DCA]) using oxygen bomb calorimetry [30...Gaseous Enthalpy of Formation of the Ionic Liquid 1-Butyl- 3-methylimidazolium Dicyanamide from Combustion Calorimetry , Vapor Pressure Measurements

  20. Dielectric relaxation and solvation dynamics in a prototypical ionic liquid + dipolar protic liquid mixture: 1-butyl-3-methylimidazolium tetrafluoroborate + water.

    PubMed

    Zhang, Xin-Xing; Liang, Min; Hunger, Johannes; Buchner, Richard; Maroncelli, Mark

    2013-12-12

    Dielectric and solvation data on mixtures of 1-butyl-3-methylimidazilium tetrafluoroborate ([Im41][BF4]) + water are reported and used to examine the utility of dielectric solvation models. Dielectric permittivity and loss spectra (25 °C) were recorded over the frequency range 200 MHz to 89 GHz at 17 compositions and fit to a 4-Debye form. Dynamic Stokes shift measurements on the solute coumarin 153 (C153), made by combining fluorescence upconversion (80 fs resolution) and time-correlated single photon counting data (20 ns range), were used to determine the solvation response at 7 compositions (20.5 °C). All properties measured here were found to depend upon mixture composition in a simple continuous manner, especially when viewed in terms of volume fraction. Solvation response functions predicted by a simple dielectric continuum model are similar to but ∼7-fold faster than the spectral response functions measured with C153. The solvation data are in better agreement with the recently published predictions of a semimolecular model of Biswas and co-workers [J. Phys. Chem. B 2011, 115, 4011], but these latter predictions are systematically slow by a factor of ∼3.

  1. Surfactant-free microemulsions of 1-butyl-3-methylimidazolium hexafluorophosphate, propylamine nitrate, and water.

    PubMed

    Xu, Jie; Deng, Huanhuan; Fu, Yunlei; Chen, Yuquan; Zhang, Jing; Hou, Wanguo

    2017-03-08

    Generally, surfactants (or amphiphiles) are believed to be necessary components of microemulsions. However, it has been demonstrated that, in the absence of traditional surfactants, microemulsions can also form from a ternary system of two immiscible fluids (i.e., oil and water phases) and an amphi-solvent, but the current understanding of such surfactant-free microemulsions (SFMEs) is very limited. Herein, we report an SFME consisting of the hydrophobic ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF6), the protic IL propylamine nitrate (PAN), and water, in which bmimPF6 and PAN are used as the oil phase and the amphi-solvent, respectively. The microstructures and structural transitions of the SFME were investigated using cyclic voltammetry, fluorescence spectroscopy, and ultraviolet-visible spectroscopy. The SFME exhibited water-in-bmimPF6 (W/IL), bicontinuous (BC), and bmimPF6-in-water (IL/W) microstructures, depending on the composition of the ternary system, similar to the case of traditional surfactant-based microemulsions (SBMEs). The three kinds of microstructures were confirmed by cryogenic transmission electron microscopy (cryo-TEM) observations. To the best of our knowledge, this is the first report on SFMEs composed of two ILs as components, especially where one is used as the amphi-solvent.

  2. Highly ordered cellulose II crystalline regenerated from cellulose hydrolyzed by 1-butyl-3-methylimidazolium chloride.

    PubMed

    Ahn, Yongjun; Song, Younghan; Kwak, Seung-Yeop; Kim, Hyungsup

    2016-02-10

    This research focused on the preparation of highly ordered cellulose II crystalline by cellulose hydrolysis in ionic liquid, and the influence of molecular mobility on recrystallization of cellulose. The molar mass of cellulose was controlled by hydrolysis using 1-butyl-3-methylimidazolium chloride (BmimCl). The molecular mobility of cellulose dissolved in BmimCl was characterized by rheological properties. After characterization of cellulose solution and regeneration, change of molar mass and conversion to crystalline were monitored using gel-permeation chromatography and powder X-ray diffraction, respectively. The molar mass of the cellulose in BmimCl was remarkably decreased with an increase in duration time, resulting in better mobility and a lower conformational constraint below critical molar mass. The decrease in molar mass surprisingly increased the crystallinity up to ∼ 85%, suggesting a recrystallization rate dependence of the mobility. The correlation between the mobility and recrystallization rate represented quit different behavior above and below a critical molar mass, which strongly demonstrated to the effect of mobility on the conversion of amorphous state to crystalline structure.

  3. Multiprobe Spectroscopic Evidence for "Hyperpolarity" within 1-Butyl-3-methylimidazolium Hexafluorophosphate Mixtures with Tetraethylene Glycol

    SciTech Connect

    Sarkar, Abhra; Trivedi, Shruti; Baker, Gary A; Pandey, Siddharth

    2008-01-01

    A hybrid, potentially green solvent system composed of tetraethylene glycol (TEG) and the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) was investigated across all mole fractions with regard to the solvent properties of the mixture. For this purpose, a suite of absorbance- and fluorescence-based solvatochromic probes were utilized to explore solute-solvent and solvent-solvent interactions existing within the [bmim][PF6] + TEG system. These studies revealed an interesting and unusual synergistic solvent effect. In particular, a remarkable hyperpolarity was observed in which the ET value, comprising dipolarity/polarizability and hydrogen bond donor (HBD) acidity contributions, at intermediate mole fractions of the binary mixture well exceeded that of the most polar pure component (i.e., [bmim][PF6]). Independently determined dipolarity/polarizability ( *) and HBD acidity (R) Kamlet-Taft values for the [bmim][PF6] + TEG mixtures were also observed to be anomalously high at intermediate mole fractions, whereas hydrogen bond acceptor (HBA) basicities ( values) were much more in line with the ideal arithmetic values predicted on a mole fraction basis.

  4. CRYSTAL POLYMORPHISM IN 1-BUTYL-3-METHYLIMIDAZOLIUM HALIDES: SUPPORTING IONIC LIQUID FORMATION THROUGH INHIBITION OF CRYSTALLIZATION. (R828257)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  5. Ionic liquid 1-butyl-3-methylimidazolium cyanamide (bmim [dca]) as a solvent and catalyst for acylation of maltodextrin

    USDA-ARS?s Scientific Manuscript database

    We have found a novel method to prepare maltodextrin stearate with DS upto 0.60 in 90% yields from maltodextrin in IL bmim[dca] reacted with vinyl stearate or stearic acid. In this work we have demonstrated that IL could simultaneously act as a solvent and as a catalyst for reaction of maltodextrin...

  6. CRYSTAL POLYMORPHISM IN 1-BUTYL-3-METHYLIMIDAZOLIUM HALIDES: SUPPORTING IONIC LIQUID FORMATION THROUGH INHIBITION OF CRYSTALLIZATION. (R828257)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  7. Comparison and Characterisation of Regenerated Chitosan from 1-Butyl-3-methylimidazolium Chloride and Chitosan from Crab Shells.

    PubMed

    Islam, Saniyat; Arnold, Lyndon; Padhye, Rajiv

    2015-01-01

    Chitosan is a biopolymer derived from chitin which is naturally occurring in the exoskeleton of crustaceans. This paper reports dissolution and regeneration of chitosan by directly dissolving in an ionic liquid solvent, 1-butyl-3-methylimidazolium chloride (BMIMCl). This will provide an ideal platform to solubilise these kinds of polymers to achieve the dissolution. The current study dissolved chitosan from crab shell utilising BMIMCl as a solvent and characterised the resultant regenerated polymer. The regenerated chitosan showed increased hydrogen bonding when characterised by Fourier transform infrared (FTIR) spectral analysis. In addition, the study also compared the characteristics of regenerated and generic chitosan. The regenerated chitosan was also evaluated for antimicrobial properties and showed to possess antibacterial features similar to the commercial grade. This method can be utilised in future for blending of polymers with chitosan in a dissolved phase.

  8. Experimental and theoretical investigation of multistage extraction of 1,3-propanediol using the extraction system phosphate/1-butyl-3-methylimidazolium trifluoromethanesulfonate/water.

    PubMed

    Müller, Anja; Lutze, Philip; Górak, Andrzej

    2013-01-01

    The separation of 1,3-propanediol from fermentation broth is a challenging and energy-demanding step using conventional unit operations. One alternative process is the use of an aqueous two-phase system incorporating ionic liquids to use synergy effects of both technologies. Within this manuscript, the technical feasibility of the extraction of 1,3-propanediol using the aqueous two-phase system phosphate (salt)/1-butyl-3-methylimidazolium trifluoromethanesulfonate (ionic liquid)/water in a continuously operated process in pilot-scale is presented. The extraction was performed in a multistage mixer-settler unit and successfully modeled with an equilibrium-stage model and correlations to describe the liquid-liquid equilibrium of the salt/ionic liquid/water two-phase system. The developed and validated model was used for a further investigation of the influence of different process parameters in the determined operating window. Theses parameters include the number of stages, the phase ratio, the pH, and the mass fraction of the involved components. The results prove that the phosphate and 1-butyl-3-methylimidazolium trifluoromethanesulfonate mass fraction, the phase ratio, and the number of stages have a considerable influence on the recovery of 1,3-propanediol, whereas the pH value has only a smaller impact. Those results can be used for optimization of the system as well as for targeting future research within this area.

  9. Photoisomerization of cyanine derivatives in 1-butyl-3-methylimidazolium hexafluorophosphate and aqueous glycerol: Influence of specific interactions

    SciTech Connect

    Mali, K. S.; Dutt, G. B.; Mukherjee, T.

    2008-03-28

    Photoisomerization of two cyanine derivatives, 3,3{sup '}-diethyloxadicarbocyanine iodide (DODCI) and merocyanine 540 (MC 540), has been investigated in an ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate and aqueous glycerol (93 wt % glycerol +7 wt % water) by measuring fluorescence lifetimes and quantum yields. The aim of this work is to understand how the rates of photoisomerization of DODCI and MC 540 are influenced by specific solute-solvent interactions besides the viscosity of the medium. For DODCI, it has been observed that the nonradiative rate constants, which represent the rates of photoisomerization, are almost identical in the ionic liquid and aqueous glycerol at given temperature, indicating that viscosity is the sole parameter that governs the rate of photoisomerization. In contrast, the photoisomerization rate constants of MC 540 have been found to be a factor of 2 higher in aqueous glycerol compared to the ionic liquid. The observed behavior is due to the zwitterionic character of MC 540, a consequence of which, the twisted state gets stabilized by the solute-solvent hydrogen bonding interactions in aqueous glycerol, thus lowering the barrier for isomerization.

  10. Multiprobe Spectroscopic Inverstigation of Molecular-level Behavior within Aqueous 1-Butyl-3-methylimidazolium Tetrafluoroborate

    SciTech Connect

    Sarkar, Abhra; Ali, Maroof; Baker, Gary A; Tetin, Sergey Y.; Ruan, Qiaoqiao; Pandey, Siddharth

    2009-01-01

    In this work, an array of molecular-level solvent featuressincluding solute-solvent/solvent-solvent interactions, dipolarity, heterogeneity, dynamics, probe accessibility, and diffusionswere investigated across the entire composition of ambient mixtures containing the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate, [bmim][BF4], and pH 7.0 phosphate buffer, based on results assembled for nine different molecular probes utilized in a range of spectroscopic modes. These studies uncovered interesting and unusual solvatochromic probe behavior within this benchmark mixture. Solvatochromic absorbance probessa watersoluble betaine dye (betaine dye 33), N,N-diethyl-4-nitroaniline, and 4-nitroanilineswere employed to determine ET (a blend of dipolarity/polarizability and hydrogen bond donor contributions) and the Kamlet-Taft indices * (dipolarity/polarizability), R (hydrogen bond donor acidity), and (hydrogen bond acceptor basicity) characterizing the [bmim][BF4] + phosphate buffer system. These parameters each showed a marked deviation from ideality, suggesting selective solvation of the individual probe solutes by [bmim][BF4]. Similar conclusions were derived from the responses of the fluorescent polarity-sensitive probes pyrene and pyrene-1-carboxaldehyde. Importantly, the fluorescent microfluidity probe 1,3-bis(1-pyrenyl)propane senses a microviscosity within the mixture that significantly exceeds expectations derived from simple interpolation of the behavior in the neat solvents. On the basis of results from this probe, a correlation between microviscosity and bulk viscosity was established; pronounced solvent-solvent hydrogen-bonding interactions were implicit in this behavior. The greatest deviation from ideal additive behavior for the probes studied herein was consistently observed to occur in the buffer-rich regime. Nitromethane-based fluorescence quenching of pyrene within the [bmim][BF4] + phosphate buffer system showed unusual compliance with a sphere

  11. Influence of the current density on the electrochemical treatment of concentrated 1-butyl-3-methylimidazolium chloride solutions on diamond electrodes.

    PubMed

    Marcionilio, Suzana M L de Oliveira; Alves, Gisele M; E Silva, Rachel B Góes; Marques, Pablo J Lima; Maia, Poliana D; Neto, Brenno A D; Linares, José J

    2016-10-01

    This paper focuses on the influence of the current density treatment of a concentrated 1-butyl-3-methylimidazolium chloride (BMImCl) solution on an electrochemical reactor with a boron-doped diamond (BDD) anode. The decrease in the total organic carbon (TOC) and the BMImCl concentration demonstrate the capability of BDD in oxidizing ionic liquids (ILs) and further mineralizing (to CO2 and NO3 (-)) more rapidly at higher current densities in spite of the reduced current efficiency of the process. Moreover, the presence of Cl(-) led to the formation of oxychlorinated anions (mostly ClO3 (-) and ClO4 (-)) and, in combination with the ammonia generated in the cathode from the nitrate reduction, chloramines, more intensely at higher current density. Finally, the analysis of the intermediates formed revealed no apparent influence of the current density on the BMImCl degradation mechanism. The current density presents therefore a complex influence on the IL treatment process that is discussed throughout this paper.

  12. Molecular dynamics simulations of n-hexane at 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide interface.

    PubMed

    Lísal, Martin; Izák, Pavel

    2013-07-07

    Molecular dynamics simulations of n-hexane adsorbed onto the interface of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([bmim][Tf2N]) are performed at three n-hexane surface densities, ranged from 0.7 to 2.3 μmol/m(2) at 300 K. For [bmim][Tf2N] room-temperature ionic liquid, we use a non-polarizable all-atom force field with the partial atomic charges based on ab initio calculations for the isolated ion pair. The net charges of the ions are ±0.89e, which mimics the anion to cation charge transfer and polarization effects. The OPLS-AA force field is employed for modeling of n-hexane. The surface tension is computed using the mechanical route and its value decreases with increase of the n-hexane surface density. The [bmim][Tf2N]/n-hexane interface is analyzed using the intrinsic method, and the structural and dynamic properties of the interfacial, sub-interfacial, and central layers are computed. We determine the surface roughness, global and intrinsic density profiles, and orientation ordering of the molecules to describe the structure of the interface. We further compute the survival probability, normal and lateral self-diffusion coefficients, and re-orientation correlation functions to elucidate the effects of n-hexane on dynamics of the cations and anions in the layers.

  13. The genotoxic and cytotoxic effects of 1-butyl-3-methylimidazolium chloride in soil on Vicia faba seedlings.

    PubMed

    Liu, Tong; Zhu, Lusheng; Wang, Jinhua; Wang, Jun; Xie, Hui

    2015-03-21

    Although considered as "green" solvents, the toxic effects of ionic liquids (ILs) on organisms have been widely investigated in recent years. However, studies on the toxic effects of ILs on plants all focus on toxicity in nutrient solution. In the present paper, the toxic effects of 1-butyl-3-methylimidazolium chloride ([C4mim]Cl) on Vicia faba seedlings in soil at 0, 500, 1500, and 2500 mg kg(-1) on day 10 were studied. The present results showed that the growth of V. faba seedlings may be seriously inhibited when the IL concentrations were higher than 500 mg kg(-1). The EC50 values for shoot length, root length, and dry weight were 3886, 2483, and 3359 mg kg(-1), respectively. In addition, [C4mim]Cl caused lipid peroxidation and DNA damage at 500 mg kg(-1) and oxidative stress at 1500 mg kg(-1), which indicated that [C4mim]Cl may have genotoxicity and cytotoxicity on V. faba seedlings. Moreover, oxidative damage may be the main toxic mechanism of ILs.

  14. Molecular dynamics simulations of n-hexane at 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide interface

    NASA Astrophysics Data System (ADS)

    Lísal, Martin; Izák, Pavel

    2013-07-01

    Molecular dynamics simulations of n-hexane adsorbed onto the interface of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([bmim][Tf2N]) are performed at three n-hexane surface densities, ranged from 0.7 to 2.3 μmol/m2 at 300 K. For [bmim][Tf2N] room-temperature ionic liquid, we use a non-polarizable all-atom force field with the partial atomic charges based on ab initio calculations for the isolated ion pair. The net charges of the ions are ±0.89e, which mimics the anion to cation charge transfer and polarization effects. The OPLS-AA force field is employed for modeling of n-hexane. The surface tension is computed using the mechanical route and its value decreases with increase of the n-hexane surface density. The [bmim][Tf2N]/n-hexane interface is analyzed using the intrinsic method, and the structural and dynamic properties of the interfacial, sub-interfacial, and central layers are computed. We determine the surface roughness, global and intrinsic density profiles, and orientation ordering of the molecules to describe the structure of the interface. We further compute the survival probability, normal and lateral self-diffusion coefficients, and re-orientation correlation functions to elucidate the effects of n-hexane on dynamics of the cations and anions in the layers.

  15. Compressed CO2-enhanced solubilization of 1-butyl-3-methylimidazolium tetrafluoroborate in reverse micelles of Triton X-100

    NASA Astrophysics Data System (ADS)

    Li, Junchun; Zhang, Jianling; Han, Buxing; Wang, Yong; Gao, Liang

    2004-10-01

    We carried out the first study about the effect of a compressed gas on the properties of reverse micellar solutions with ionic liquid (IL) polar cores. And the properties of compressed CO2/cyclohexane/1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4])/Triton X-100 (TX-100) system were investigated at 288.2, 293.2, 298.2, 308.2 K and different pressures by using phase behavior measurement, small-angle x-ray scattering, and UV-Vis techniques. The concentration of the surfactant in the solution was 0.3 mol/l (M). It was found that compressed CO2 could enhance solubilization of the IL in the reverse micelles considerably at suitable pressures, and formation of the reverse micelles could be controlled easily by pressure. Increase of CO2 pressure resulted in decrease of the micellar sizes at fixed [bmim][BF4]-to-surfactant molar ratios (w), and the size of the reverse micelles increased with the increase of w values. The polarity of the IL cores increased continuously with increasing w value.

  16. Molecular dynamics simulations of n-hexane at 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide interface

    SciTech Connect

    Lisal, Martin; Izak, Pavel

    2013-07-07

    Molecular dynamics simulations of n-hexane adsorbed onto the interface of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([bmim][Tf{sub 2}N]) are performed at three n-hexane surface densities, ranged from 0.7 to 2.3 {mu}mol/m{sup 2} at 300 K. For [bmim][Tf{sub 2}N] room-temperature ionic liquid, we use a non-polarizable all-atom force field with the partial atomic charges based on ab initio calculations for the isolated ion pair. The net charges of the ions are {+-}0.89e, which mimics the anion to cation charge transfer and polarization effects. The OPLS-AA force field is employed for modeling of n-hexane. The surface tension is computed using the mechanical route and its value decreases with increase of the n-hexane surface density. The [bmim][Tf{sub 2}N]/n-hexane interface is analyzed using the intrinsic method, and the structural and dynamic properties of the interfacial, sub-interfacial, and central layers are computed. We determine the surface roughness, global and intrinsic density profiles, and orientation ordering of the molecules to describe the structure of the interface. We further compute the survival probability, normal and lateral self-diffusion coefficients, and re-orientation correlation functions to elucidate the effects of n-hexane on dynamics of the cations and anions in the layers.

  17. Synergistic Effect of 1-Butyl-3-methylimidazolium Hexafluorophosphate and DMSO in the SARA ATRP at Room Temperature Affording Very Fast Reactions and Polymers with Very Low Dispersity

    PubMed Central

    2015-01-01

    An unusual synergistic effect between 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6) and dimethyl sulfoxide (DMSO) mixtures is reported for the supplemental activator and reducing agent atom transfer radical polymerization (SARA ATRP) of methyl acrylate (MA) using a catalytic system composed by sodium dithionate (Na2S2O4) and CuBr2/Me6TREN (Me6TREN: tris[2-(dimethylamino)ethyl]amine) at room temperature. To the best of our knowledge, the use of ionic liquids (IL) has never been reported for the SARA ATRP. The kinetic data obtained for a broad range of target molecular weights revealed very fast polymerization rates, low dispersity values (Đ < 1.05) and well-defined chain-end functionalities. PMID:25068078

  18. Synergistic Effect of 1-Butyl-3-methylimidazolium Hexafluorophosphate and DMSO in the SARA ATRP at Room Temperature Affording Very Fast Reactions and Polymers with Very Low Dispersity.

    PubMed

    Mendes, Joana P; Branco, Fábio; Abreu, Carlos M R; Mendonça, Patrícia V; Popov, Anatoliy V; Guliashvili, Tamaz; Serra, Arménio C; Coelho, Jorge F J

    2014-06-17

    An unusual synergistic effect between 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6) and dimethyl sulfoxide (DMSO) mixtures is reported for the supplemental activator and reducing agent atom transfer radical polymerization (SARA ATRP) of methyl acrylate (MA) using a catalytic system composed by sodium dithionate (Na2S2O4) and CuBr2/Me6TREN (Me6TREN: tris[2-(dimethylamino)ethyl]amine) at room temperature. To the best of our knowledge, the use of ionic liquids (IL) has never been reported for the SARA ATRP. The kinetic data obtained for a broad range of target molecular weights revealed very fast polymerization rates, low dispersity values (Đ < 1.05) and well-defined chain-end functionalities.

  19. States of water located in the continuous organic phase of 1-butyl-3-methylimidazolium tetrafluoroborate/Triton X-100/triethylamine reverse microemulsions.

    PubMed

    Li, Na; Cao, Quan; Gao, Yanan; Zhang, Jin; Zheng, Liqiang; Bai, Xiangtao; Dong, Bin; Li, Zhen; Zhao, Mingwei; Yu, Li

    2007-10-22

    We demonstrate a novel ionic liquid (IL) microemulsion, consisting of 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF4) and nonionic surfactant Triton X-100 prepared in triethylamine which is used either as an organic solvent or a Lewis base. The effects of small amounts of added water on the microstructure of the IL microemulsion are investigated by various techniques. UV/Vis spectroscopic analysis and FTIR spectra indicate that these water molecules are not solubilized into the IL pools of the microemulsions. 1H NMR spectra further show that the added water binds with triethylamine to form a surrounding OH- base environment. Some of OH- ions enter the palisade layers of the IL microemulsions and a continuous base interface is created. The unique solubilization behavior of water reveals that it is possible to use the triethylamine microemulsions as a template to prepare metal hydroxides as well as metal oxides in the microemulsions, which is not possible when using traditional microemulsions.

  20. A novel, sensitive, reusable and low potential acetylcholinesterase biosensor for chlorpyrifos based on 1-butyl-3-methylimidazolium tetrafluoroborate/multiwalled carbon nanotubes gel.

    PubMed

    Zamfir, Lucian-Gabriel; Rotariu, Lucian; Bala, Camelia

    2011-04-15

    A novel, low potential and highly sensitive acetylcholinesterase (AChE) biosensor was developed based on 1-butyl-3-methylimidazolium tetrafluoroborate/multiwalled carbon nanotube composite gel thiocholine sensor. Composite gel promoted electron transfer reaction at a lower potential (+50 mV) and catalyzed electrochemical oxidation of thiocholine with high sensitivity. AChE was immobilized in sol-gel matrix that provides a good support for enzyme without any inhibition effect from the ionic liquid. The amount of immobilized enzyme and incubation time with chlorpyrifos were optimized. Chlorpyrifos could be determined in the range of 10(-8)-10(-6)M with a detection limit of 4 nM. Fast and efficient enzyme reactivation was obtained at low obidoxime concentration (0.1mM). Moreover, the biosensor exhibited a good stability and reproducibility and could be use for multiple determinations of pesticide with no loss of the enzyme activity.

  1. Ionic liquid-in-oil microemulsions.

    PubMed

    Eastoe, Julian; Gold, Sarah; Rogers, Sarah E; Paul, Alison; Welton, Tom; Heenan, Richard K; Grillo, Isabelle

    2005-05-25

    Phase stability and small-angle neutron scattering (SANS) data show that surfactant-stabilized nanodomains of a typical ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate [bmim][BF4]) may be dispersed by the nonionic surfactant Triton-X100 in cyclohexane. Analyses of these SANS data are consistent with the formation of ionic liquid-in-oil microemulsion droplets.

  2. Esterification of Starch in Ionic Liquids

    USDA-ARS?s Scientific Manuscript database

    We shall discuss the use of various ionic liquids in the preparation of starch esters. Starch was reacted with vinyl acetate in different 1-butyl-3-methylimidazolium (bmim) salts as solvents in an effort to produce starches with different acetylation patterns. Overall degree of substitution (DS) w...

  3. Ultraviolet Photoionization Efficiency of the Vaporized Ionic Liquid 1-Butyl-3-Methylimidazolium Tricyanomethanide: Direct Detection of the Intact Ion Pair (Post Print)

    DTIC Science & Technology

    2012-09-21

    Lovelock , K. R. J.; Satterly, C. J.; Villar-Garcia, I. J. Phys. Chem. Chem. Phys. 2007, 9, 982−990. (11) Strasser, D.; Goulay, F.; Kelkar, M. S.; Maginn, E...J.; Leone, S. R. J. Phys. Chem. A 2007, 111, 3191−3915. (12) Lovelock , K. R. J.; Deyko, A.; Corfield, J.-A.; Gooden, P. N.; Licence, P.; Jones, R. G

  4. Thermodynamic, Dynamic, and Structural Properties of Ionic Liquids Comprised of 1-butyl-3-methylimidazolium Cation and Nitrate, Azide, or Dicyanamide Anions

    DTIC Science & Technology

    2010-04-28

    Voth used a coarse-grained model to investigate spatial heterogeneities in alkyl imidazolium based ILs with NO3 anion.xxii These simulations showed... imidazolium -based cations and N3 anion have been reported in the literature. II. Simulation details. Subsequently to the publication of the original...by examining atomistic intermolecular pair distribution functions. Specifically, in Figure 3 we show g(r) between hydrogens on imidazolium ring (Hi

  5. Microemulsions with an ionic liquid surfactant and room temperature ionic liquids as polar pseudo-phase.

    PubMed

    Zech, Oliver; Thomaier, Stefan; Bauduin, Pierre; Rück, Thomas; Touraud, Didier; Kunz, Werner

    2009-01-15

    In this investigation we present for the first time microemulsions comprising an ionic liquid as surfactant and a room-temperature ionic liquid as polar pseudo-phase. Microemulsions containing the long- chain ionic liquid1-hexadecyl-3-methyl-imidazolium chloride ([C16mim][Cl]) as surfactant, decanol as cosurfactant, dodecaneas continuous phase and room temperature ionic liquids (ethylammonium nitrate (EAN) and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim

  6. Decrease of droplet size of the reverse microemulsion 1-butyl-3-methylimidazolium tetrafluoroborate/Triton X-100/cyclohexane by addition of water.

    PubMed

    Gao, Yanan; Hilfert, Liane; Voigt, Andreas; Sundmacher, Kai

    2008-03-27

    In the present contribution, results concerning the role of small amounts of water in the 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF4)-in-cyclohexane ionic liquid (IL) reverse microemulsions are reported. Dynamic light scattering (DLS) revealed that the size of microemulsion droplets decreased remarkably with increasing water content although water is often used as a polar component to swell reverse microemulsions. It was thus deduced that the number of microemulsion droplets was increased which was confirmed by conductivity measurements. The states of dissolved water were investigated by Fourier transform IR (FTIR) spectroscopic analysis showing that water molecules mainly act as bound water. 1H NMR along with two-dimensional rotating frame nuclear Overhauser effect (NOE) experiments (ROESY) further revealed that water molecules were mainly located in the periphery of the polar core of the microemulsion droplets and behave like a chock being inserted in the palisade layer of the droplet. This increased the curvature of the surfactant film at the IL/cyclohexane interface and thus led to the decrease of the microemulsion droplet size. The order of surfactant molecules arranged in the interface film was increased and thus induced a loss of entropy. Isothermal titration calorimetry (ITC) indicated that an enthalpy increase compensates for the loss of entropy during the process of microstructural transition.

  7. 1-Butyl-3-Methylimidazolium Tetrafluoroborate Film as a Highly Selective Sensing Material for Non-Invasive Detection of Acetone Using a Quartz Crystal Microbalance

    PubMed Central

    Tao, Wenyan; Lin, Peng; Liu, Sili; Xie, Qingji; Ke, Shanming; Zeng, Xierong

    2017-01-01

    Breath acetone serves as a biomarker for diabetes. This article reports 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]), a type of room temperature ionic liquid (RTIL), as a selective sensing material for acetone. The RTIL sensing layer was coated on a quartz crystal microbalance (QCM) for detection. The sensing mechanism is based on a decrease in viscosity and density of the [bmim][BF4] film due to the solubilization of acetone leading to a positive frequency shift in the QCM. Acetone was detected with a linear range from 7.05 to 750 ppmv. Sensitivity and limit of detection were found to be 3.49 Hz/ppmv and 5.0 ppmv, respectively. The [bmim][BF4]-modified QCM sensor demonstrated anti-interference ability to commonly found volatile organic compounds in breath, e.g., isoprene, 1,2-pentadiene, d-limonene, and dl-limonene. This technology is useful for applications in non-invasive early diabetic diagnosis. PMID:28117697

  8. MICROWAVE-ASSISTED PREPARATION OF 1-BUTYL-3-METHYLIMIDAZOLIUM TETRACHLOROGALLATE AND ITS CATALYTIC USE IN ACETAL FORMATION UNDER MILD CONDITIONS

    EPA Science Inventory

    1-Butyl-3-methylimidazolium tetrachlorogallate, [bmim][GaCl4], prepared via microwave-assisted protocol, is found to be an active catalyst for the efficient acetalization of aldehydes under mild conditions.

  9. Ionic Liquid as a Solvent and Catalyst for Acylation of Maltodextrin

    USDA-ARS?s Scientific Manuscript database

    Catalyst-free esterification of maltodextrin was carried out in ionic liquid. Stearate esters of maltodextrin were obtained in various degree of substitution (DS) when vinyl stearate or stearic acid was heated with maltodextrin in ionic liquid, 1-butyl-3-methylimidazolium cyanamide (bmim[dca]). Re...

  10. Enzymatic Transesterification of Kraft Lignin with Long Acyl Chains in Ionic Liquids.

    PubMed

    Hulin, Lise; Husson, Eric; Bonnet, Jean-Pierre; Stevanovic, Tatjana; Sarazin, Catherine

    2015-09-09

    Valorization of lignin is essential for the economic viability of the biorefinery concept. For example, the enhancement of lignin hydrophobicity by chemical esterification is known to improve its miscibility in apolar polyolefin matrices, thereby helping the production of bio-based composites. To this end and due to its many reactive hydroxyl groups, lignin is a challenging macromolecular substrate for biocatalyzed esterification in non-conventional media. The present work describes for the first time the lipase-catalyzed transesterification of Kraft lignin in ionic liquids (ILs). Three lipases, three 1-butyl-3-methylimidazolium based ILs and ethyl oleate as long chain acyl donor were selected. Best results were obtained with a hydrophilic/hydrophobic binary IL system (1-butyl-3-methylimidazolium trifluoromethanesulfonate/1-butyl-3-methylimidazolium hexafluoro- phosphate, 1/1 v/v) and the immobilized lipase B from Candida antarctica (CALB) that afforded a promising transesterification yield (ca. 30%). Similar performances were achieved by using 1-butyl-3-methylimidazolium hexafluorophosphate as a coating agent for CALB rather than as a co-solvent in 1-butyl-3-methylimidazolium trifluoromethane-sulfonate thus limiting the use of hydrophobic IL. Structural characterization of lignin oleate was performed by spectroscopic studies (FTIR and ¹H-NMR). The synthesized lignin oleate exhibited interesting thermal and textural properties, different from those of the original Kraft lignin.

  11. Short Time Dynamics of Ionic Liquids in AIMD-Based Power Spectra.

    PubMed

    Wendler, Katharina; Brehm, Martin; Malberg, Friedrich; Kirchner, Barbara; Delle Site, Luigi

    2012-05-08

    Power spectra of several imidazolium-based ionic liquids, 1,3-dimethylimidazolium chloride, 1-ethyl-3-methylimidazolium thiocyanate, 1-ethyl-3-methylimidazolium dicyanamide 5, 1-butyl-3-methylimidazolium chloride, 1-butyl-3-methylimidazolium thiocyanate, and 1-butyl-3-methylimidazolium dicyanamide, are presented based on ab initio molecular dynamics simulations. They provide an alternative tool of analysis of several electronic structure-based properties, in particular, those related to the strength of hydrogen bonding in liquids. Moreover, they can be employed to interpret experimental IR or Raman spectra, avoiding the additional calculations required for theoretical IR or Raman spectra. The obtained power spectra are shown to be in good agreement with experimental spectra, and electronic structure properties related to them are analyzed. Further, there are indications for a locality of the power spectra on a relatively short time scale of ≈10 ps or system size of about 8 ion pairs as already speculated in previous work.

  12. Understanding lignin treatment in dialkylimidazolium-based ionic liquid-water mixtures.

    PubMed

    Yan, Bing; Li, Kunlan; Wei, Ligang; Ma, Yingchong; Shao, Guolin; Zhao, Deyang; Wan, Wenying; Song, Lili

    2015-11-01

    The treatment of enzymatically hydrolyzed lignin (EHL) in dialkylimidazolium-based ionic liquid (IL)-water mixtures (50-100wt% IL content) was investigated at 150°C for 3h. pH, IL type, and IL content were found to greatly influence the degradation of lignin and the structure of regenerated lignin. 1-Butyl-3-methylimidazolium methylsulfonate-water mixtures with low pH facilitated lignin depolymerization but destroyed the regenerated lignin substructure. Regenerated lignin with low molecular weight and narrow polydispersity index (2.2-7.7) was obtained using a 1-butyl-3-methylimidazolium acetate-based system. Water addition inhibited lignin depolymerization at 50-100wt% IL content, except for 70wt% 1-butyl-3-methylimidazolium chloride-water mixture. Compared with pure IL treatment, obvious differences were observed in the breakdown of inter-unit linkages and ratio of syringyl to guaiacyl units in regenerated lignin with IL-water treatment.

  13. Theoretical study on interactions between lignocellulose components and ionic liquids

    NASA Astrophysics Data System (ADS)

    Wang, J.; Zhuang, W. C.; Shi, X. Q.; Cao, W. L.

    2017-09-01

    Interactions between lignocellulose and ionic liquids have been studied by designed lignocellulose components models, and their complexes with 1-butyl-3-methylimidazolium chloride. All the structures were optimized by DFT methods and hydrogen bonds within lignocelluloses components, and their complexes with 1-butyl-3-methylimidazolium chloride were investigated by AIM calculations. Our calculated results demonstrate that when dissolved in ionic liquids, the stable intermolecular hydrogen bonds and weak π-stacking interactions between ionic liquids and lignocelluloses components reduce the energy of complex systems, which are advantageous for lignocelluloses components dissolution in ionic liquids. Moreover, there are deformation accrued for both lignocelluloses components and ionic liquids, which may be a prerequisite for lignocelluloses components dissolution in ionic liquids.

  14. Properties of an ionic liquid-tolerant Bacillus amyloliquefaciens CMW1 and its extracellular protease.

    PubMed

    Kurata, Atsushi; Senoo, Humiya; Ikeda, Yasuyuki; Kaida, Hideaki; Matsuhara, Chiaki; Kishimoto, Noriaki

    2016-07-01

    An ionic liquid-tolerant bacterium, Bacillus amyloliquefaciens CMW1, was isolated from a Japanese fermented soybean paste. Strain CMW1 grew in the presence of 10 % (v/v) 1-butyl-3-methylimidazolium chloride ([BMIM]Cl), a commonly used ionic liquid. Additionally, strain CMW1 grew adequately in the presence of the hydrophilic ionic liquids 10 % (v/v) 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([EMIM]CF3SO3) or 2.5 % (v/v) 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([BMIM]CF3SO3). Strain CMW1 produced an extracellular protease (BapIL) in the culture medium. BapIL was stable in the presence of 80 % (v/v) ionic liquids, [EMIM]CF3SO3, [BMIM]Cl, [BMIM]CF3SO3, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, and functioned in 10 % (v/v) these ionic liquids. BapIL was stable at pH 4.0-12.6 or in 4004 mM NaCl solution, and exhibited activity in the presence of 50 % (v/v) hydrophilic or hydrophobic organic solvents. BapIL was completely inhibited by 1 mM PMSF and partially by 5 mM EDTA. BapIL belongs to the true subtilisins according to analysis of the deduced amino acid sequence. We showed that BapIL from the ionic liquid-tolerant B. amyloliquefaciens CMW1 exhibited tolerance to ionic liquid and halo, alkaline, and organic solvents.

  15. Phase Behavior of N2O and CO2 in Room-Temperature Ionic Liquids [bmim][Tf2N], [bmim][BF4], [bmim][N(CN)2], [bmim][Ac], [eam][NO3], and [bmim][SCN

    NASA Astrophysics Data System (ADS)

    Shiflett, Mark B.; Niehaus, Anne Marie S.; Elliott, Beth A.; Yokozeki, A.

    2012-03-01

    The gas solubility of nitrous oxide (N2O) in room-temperature ionic liquids, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium dicyanamide, 1-butyl-3-methylimidazolium acetate, 1-butyl-3-methylimidazolium thiocyanate, and ethylammonium nitrate has been measured at isothermal conditions from about (283 to 348)K using a gravimetric microbalance. The observed pressure-temperature composition ( PTx) data have been analyzed by use of a generic Redlich-Kwong equation-of-state (EOS) model, which has been successfully applied in our previous works. The interaction parameters have been determined using our measured vapor-liquid equilibrium data. Vapor-liquid-liquid equilibrium measurements have been made and validate EOS model predictions which suggest that these systems demonstrate Type III and Type V phase behavior, according to the classification of van Konynenburg and Scott. The global phase behavior of N2O has also been compared with both the measured data from this study and literature data for carbon dioxide (CO2) in each ionic liquid and Henry's law constants are compared at room temperature (298.15 K).

  16. Optimization of oligomeric enzyme activity in ionic liquids using Rhodotorula glutinis yeast phenylalanine ammonia lyase.

    PubMed

    Barron, Christiaan C; Sponagle, Brandon J D; Arivalagan, Pugazhendhi; D'Cunha, Godwin B

    2017-01-01

    Phenylalanine ammonia lyase (E.C.4.3.1.24, PAL) activity of Rhodotorula glutinis yeast has been demonstrated in four commonly used ionic liquids. PAL forward reaction was carried out in 1-butyl-3-methylimidazolium methyl sulfate ([BMIM][MeSO4]), 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]), 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) and 1-butyl-3-methylimidazolium lactate ([BMIM][lactate]). Our experiments have revealed that PAL is catalytically active in ionic liquids and the enzyme activity in ([BMIM][PF6]) is comparable to that obtained in aqueous buffer medium. Different conditions were optimized for maximal PAL forward activity including time of incubation (30.0min)L-phenylalanine substrate concentration (30.0mM), nature of buffer (50.0mM Tris-HCl), pH (9.0), temperature (37°C), and speed of agitation (100 rev min(-1)). Under these optimized conditions, about 83% conversion of substrate to product was obtained for the PAL forward reaction that was determined using UV spectroscopy at 290nm. PAL reverse reaction in ([BMIM][PF6]) was determined spectrophotometrically at 520nm; and about 59% substrate conversion was obtained. This data provides further knowledge in enzyme biocatalysis in non-aqueous media, and may be of importance when studying the function of other oligomeric/multimeric proteins and enzymes in ionic liquids. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Understanding the dissolution of cellulose in 1-butyl-3-methylimidazolium acetate+DMAc solvent.

    PubMed

    Xu, Airong; Guo, Xin; Xu, Rui

    2015-11-01

    Cellulose solvent ([C4mim][CH3COO]/DMAc) could be obtained by adding N,N-dimethylacetamide (DMAc) in 1-butyl-3-methylimidazolium acetate ([C4mim][CH3COO]). The solubilities of cellulose in [C4mim][CH3COO]/DMAc solvents were determined at 25°C. The effects of molar ratio of DMAc to [C4mim][CH3COO] on cellulose solubility and the possible dissolution mechanism of cellulose in [C4mim][CH3COO]/DMAc solvent have been studied. Moreover, the regenerated cellulose from [C4mim][CH3COO]/DMAc solvent were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). It was found that, cellulose was more readily dissolved in [C4mim][CH3COO]/DMAc solvent than in a neat [C4mim][CH3COO], which mainly attributed to the increased "free" [CH3COO](-) anions and [C4mim](+) cations which result from the dissociation of [C4mim][CH3COO] by DMAc. Moreover, the regenerated cellulose from [C4mim][CH3COO]/DMAc solvent displayed good thermostability and similar molecular structure to the original cellulose.

  18. A Sustainable Approach to the Stereoselective Synthesis of Diazaheptacyclic Cage Systems Based on a Multicomponent Strategy in an Ionic Liquid.

    PubMed

    Suresh Kumar, Raju; Almansour, Abdulrahman I; Arumugam, Natarajan; Altaf, Mohammad; Menéndez, José Carlos; Kumar, Raju Ranjith; Osman, Hasnah

    2016-01-29

    The microwave-assisted three-component reactions of 3,5-bis(E)-arylmethylidene]tetrahydro-4(1H)-pyridinones, acenaphthenequinone and cyclic α-amino acids in an ionic liquid, 1-butyl-3-methylimidazolium bromide, occurred through a domino sequence affording structurally intriguing diazaheptacyclic cage-like compounds in excellent yields.

  19. Application of the Bahe's pseudolattice-theory to water-1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF(4)) mixtures at 298.15K Part I. Autoprotolysis constants.

    PubMed

    Bou Malham, I; Letellier, P; Turmine, M

    2007-04-15

    The autoprotolysis constants (K(s)) of water - 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF(4)) mixtures were determined at 298K over the composition range of 0 to 77.43vol.% bmimBF(4) using potentiometric method with a glass electrode. A slight increase in the autoprotolysis constant was observed when the salt was added to the water. The value of the ionic product of the medium then decreases as the bmimBF(4) content increases from about 20vol.%. The acid-base properties of these media were perfectly described by Bahe's approaches that were completed by Varela et al. concerning structured electrolyte solutions with large short-range interactions.

  20. Determination of solute partition behavior with room-temperature ionic liquid based micellar gas-liquid chromatography stationary phases using the pseudophase model.

    PubMed

    Lantz, Andrew W; Pino, Verónica; Anderson, Jared L; Armstrong, Daniel W

    2006-05-19

    The use of micelles in ionic liquid based gas-chromatography stationary phases was evaluated using equations derived for a "three-phase" model. This model allows the determination of all three partition coefficients involved in the system, and elucidates the micellar contribution to retention and selectivity. Four types of micellar-ionic liquid columns were examined in this study: 1-butyl-3-methylimidazolium chloride with sodium dodecylsulfate or dioctyl sulfosuccinate, and 1-butyl-3-methylimidazolium hexafluorophosphate with polyoxyethylene-100-stearyl ether or polyoxyethylene-23-lauryl ether. The partition coefficients were measured for a wide range of probe molecules capable of a variety of types and magnitudes of interactions. In general, most probe molecules preferentially partitioned to the micellar pseudophase over the bulk ionic liquid component of the stationary phase. Therefore, addition of surfactant to the stationary phase usually resulted in greater solute retention. It is also shown that the selectivity of the stationary phase is significantly altered by the presence of micelles, either by enhancing or lessening the separation. The effects of surfactant on the interaction parameters of the stationary phase are determined using the Abraham solvation parameter model. The addition of sodium dodecylsulfate and dioctyl sulfosuccinate to 1-butyl-3-methylimidazolium chloride stationary phases generally increased the phase's hydrogen bond basicity and increased the level of dispersion interaction. Polyoxyethylene-100-stearyl ether and polyoxyethylene-23-lauryl ether surfactants, however, enhanced the pi-pi/n-pi, polarizability/dipolarity, and hydrogen bond basicity interactions of 1-butyl-3-methylimidazolium hexafluorophosphate to a greater degree than the ionic surfactants with 1-butyl-3-methylimidazolium chloride. However, these nonionic surfactants appeared to hinder the ability of the stationary phase to interact with solutes via dispersion forces

  1. Influence of cation structure on binary liquid-liquid equilibria for systems containing ionic liquids based on trifluoromethanesulfonate anion with hydrocarbons.

    PubMed

    Marciniak, Andrzej; Karczemna, Ewa

    2010-04-29

    Binary liquid-liquid equilibria for 15 systems containing an ionic liquid (1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methylpyridinium trifluoromethanesulfonate, 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate) with a hydrocarbon (n-hexane, n-heptane, cyclohexane, benzene, toluene) were measured by the dynamic method. The influence of cation structure of trifluoromethanesulfonate anion based ionic liquids on solubility of aliphatic and aromatic hydrocarbons is discussed.

  2. A DFT investigation on interactions between lignin and ionic liquids

    NASA Astrophysics Data System (ADS)

    Wang, Ju; Shi, Xiaoqin; Du, Xihua; Cao, Weiliang

    2017-08-01

    The interactions of the lignin model, the lignin oligomer with degree of polymerization n = 2, with 1-butyl-3-methylimidazolium chloride ionic liquid were investigated through DFT calculations in detail. Computational results revealed that lignin dissolution in ionic liquids should be a result of the joint interactions of lignin with anion and cation of ionic liquid, and the formation of ion pair weakens the interactions between lignin and ionic liquid components. Unlike the dominant H-bonds within the lignin-anion interactions, the lignin-cation interactions involve a combination of hydrogen bond and π-stacking. These results would provide mechanistic insights and suggestions for lignocellulosic dissolution in ionic liquids.

  3. Lipid extraction from microalgae using a single ionic liquid

    DOEpatents

    Salvo, Roberto Di; Reich, Alton; Dykes, Jr., H. Waite H.; Teixeira, Rodrigo

    2013-05-28

    A one-step process for the lysis of microalgae cell walls and separation of the cellular lipids for use in biofuel production by utilizing a hydrophilic ionic liquid, 1-butyl-3-methylimidazolium. The hydrophilic ionic liquid both lyses the microalgae cell walls and forms two immiscible layers, one of which consists of the lipid contents of the lysed cells. After mixture of the hydrophilic ionic liquid with a suspension of microalgae cells, gravity causes a hydrophobic lipid phase to move to a top phase where it is removed from the mixture and purified. The hydrophilic ionic liquid is recycled to lyse new microalgae suspensions.

  4. Anion effects in the extraction of lanthanide 2-thenoyltrifluoroacetone complexes into an ionic liquid

    SciTech Connect

    Jensen, Mark P.; Beitz, James V.; Rickert, Paul G.; Borkowski, Marian; Laszak, Ivan; Dietz, Mark L.

    2012-07-01

    The extraction of trivalent lanthanides from an aqueous phase containing 1 M NaClO{sub 4} into the room temperature ionic liquid 1-butyl-3-methylimidazolium nonafluoro-1-butane sulfonate by the beta-diketone extractant 2-thenoyltrifluoroacetone (Htta) was studied. Radiotracer distribution, absorption spectroscopy, time-resolved laser-induced fluorescence spectroscopy, and X-ray absorption fine structure measurements point to the extraction of multiple lanthanide species. At low extractant concentrations, fully hydrated aqua cations of the lanthanides are present in the ionic liquid phase. As the extractant concentration is increased 1:2 and 1:3 lanthanide:tta species are observed. In contrast, 1:4 Ln:tta complexes were observed in the extraction of lanthanides by Htta into 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide. (authors)

  5. Cellulose/gold nanocrystal hybrids via an ionic liquid/aqueous precipitation route.

    PubMed

    Li, Zhonghao; Taubert, Andreas

    2009-11-18

    Injection of a mixture of HAuCl(4) and cellulose dissolved in the ionic liquid (IL) 1-butyl-3-methylimidazolium chloride [Bmim]Cl into aqueous NaBH4 leads to colloidal gold nanoparticle/cellulose hybrid precipitates. This process is a model example for a very simple and generic approach towards (noble) metal/cellulose hybrids, which could find applications in sensing, sterile filtration, or as biomaterials.

  6. The effects of dose and route on the toxicokinetics and disposition of 1-butyl-3-methylimidazolium chloride in male F-344 rats and female B6C3F1 mice.

    PubMed

    Sipes, I G; Knudsen, G A; Kuester, R K

    2008-02-01

    These studies characterize the effect of dose and route of administration on the disposition and elimination of the ionic liquid, 1-butyl-3-methylimidazolium chloride (Bmim-Cl). After i.v. (5 mg/kg) or oral (50 mg/kg) administration to male F-344 rats [(14)C]Bmim-Cl detected in blood decreased rapidly. Clearance rates from the blood after i.v. and oral administration were similar (7.4 and 11.9 ml/min, respectively). Systemic bioavailability was determined to be 62.1% of a 50 mg/kg dose in rats. Urinary excretion of the parent compound by rats was the major route of elimination (i.v.: 91% in 24 h; oral: 55-74% in 24 h). The rates and routes of elimination were not affected by escalation of dose (0.5-50 mg/kg) or repeated oral administration (five daily administrations, 50 mg/kg) and were similar in male rats and B6C3F1 female mice (86-95% of dose eliminated in 24 h). Apparent systemic exposure to Bmim-Cl after dermal administration was dependent upon vehicle, as assessed by the percentage of dose eliminated in urine after application in a particular vehicle (water: 1%; ethanol/water: 3%; and dimethylformamide/water: 13% of dose). Regardless of gender, species, dose, route, or number of exposures, high-pressure liquid chromatography-UV/visible-radiometric analyses of urine samples showed a single peak that coeluted with the Bmim-Cl standard. These studies illustrate that systemic bioavailability of Bmim-Cl is high, tissue disposition and metabolism are negligible, and absorbed compound is extensively extracted by the kidney and eliminated in the urine as the parent compound.

  7. Molecularly imprinted SPE coupled with HPLC for the selective separation and enrichment of alkyl imidazolium ionic liquids in environmental water samples.

    PubMed

    Xia, Gao; Jing, Fan; Guifen, Zhu; Xiaolong, Wang; Jianji, Wang

    2013-10-01

    A novel 1-butyl-3-methylimidazolium chloride ionic liquid surface imprinted solid-phase sorbent was synthesized. The as-prepared material was characterized by SEM, Brunauer-Emmett-Teller surface area analysis and Fourier Transform IR measurements. Then its adsorption properties for alkyl imidazolium ionic liquids, including adsorption capacities, adsorption kinetics, and properties of selective separation and enrichment were studied in detail. It was shown that the ionic liquid surface imprinted polymer exhibited high selective recognition characteristics for the imidazolium chloride ionic liquids with short alkyl chains (C(n)mimCl, n = 2, 4, 6, 8) and the adsorption equilibrium was achieved within 25 min. Various parameters were optimized for the 1-butyl-3-methylimidazolium chloride ionic liquid surface imprinted polymer SPE column, such as flow rate, eluent solvent, selectivity, and reusability of the column. Then, the SPE column coupled with HPLC was used for the determination of alkyl imidazolium ionic liquids. Experimental results showed that the existence of their structural analogs and common concomitants in environmental matrices did not affect the enrichment of 1-butyl-3-methyl imidazolium chloride ionic liquid. The average recoveries of 1-butyl-3-methylimidazolium chloride ionic liquid in spiked water samples were in the range of 92.0-102.0% with the RSD lower than 5.8%.

  8. Direct synthesis of silver nanoparticles in ionic liquid

    NASA Astrophysics Data System (ADS)

    Corrêa, Cíntia M.; Bizeto, Marcos A.; Camilo, Fernanda F.

    2016-05-01

    Ionic liquids have structural organization at nanoscale that can trigger the spontaneous ordering of structures in nanoscopic range. Due to this characteristic, several metal nanoparticles have been prepared in this media. In this paper, we describe the direct preparation of silver nanoparticles in the following imidazolium ionic liquids: 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1,2-dimethyl-3-butylimidazolium bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-octyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, and in citrate tetrabutylammonium, that is an ionic liquid that acts as solvent and reducing agent at the same time. We also evaluated the morphology of the nanoparticles and the stability of the dispersions. Spherical silver nanoparticles with surface Plasmon bands in the range of 400-430 nm were produced in all the ionic liquids, with the only exception for the 1-octyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide that produced a black precipitate. The best results were obtained by using 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide and citrate tetrabutylammonium ionic liquids. The former resulted in concentrated spherical silver nanoparticles dispersion (ca. 1.0 mM of Ag) with diameters ranging from 6 to 12 nm and by adding polyvinylpyrrolidone (PVP) to the dispersions they became stable for at least 1 month. The citrate tetrabutylammonium ionic liquid produced even more concentrated dispersion of spherical silver nanoparticles with diameters ranging from 2 to 6 nm. These dispersions were quite stable without the need of PVP, since the Plasmon band in the electronic absorption spectra remained unaltered for months after the preparation. The citrate tetrabutylammonium ionic liquid offers a slow kinetic for the silver nanoparticle formation as the citrate is a milder reducing agent than borohydride.

  9. Ionic liquids influence on the surface properties of electron beam irradiated wood

    NASA Astrophysics Data System (ADS)

    Croitoru, Catalin; Patachia, Silvia; Doroftei, Florica; Parparita, Elena; Vasile, Cornelia

    2014-09-01

    In this paper, the influence of three imidazolium-based ionic liquids (1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate and 1-hexyl-3-methylimidazolium chloride) on the structure and surface properties of sycamore maple (Acer pseudoplatanus) veneers submitted to electron beam irradiation with a dose of 50 kGy has been studied by using Fourier transform infrared spectroscopy, as well as image, scanning electron microscopy/SEM/EDX, atomic force microscopy and contact angle analysis. The experimental results have proven that the studied ionic liquids determine a better preservation of the structural features of wood (cellulose crystallinity index and lignin concentration on the surface) as well as some of surface properties such as surface energy, roughness, color upon irradiation with electron beam, in comparison with the reference wood, but surface composition is changed by treatment with imidazolium-based ionic liquids mainly with 1-butyl-3-methylimidazolium tetrafluoroborate. Also, under electron beam irradiation covalent bonding of the imidazolium moiety to wood determines a higher resistance to water penetration and spreading on the surface.

  10. Accurate measurements of thermodynamic properties of solutes in ionic liquids using inverse gas chromatography.

    PubMed

    Mutelet, Fabrice; Jaubert, Jean-Noël

    2006-01-13

    Activity coefficients at infinite dilution of 29 organic compounds in two room temperature ionic liquids were determined using inverse gas chromatography. The measurements were carried out at different temperatures between 323.15 and 343.15K. To establish the influence of concurrent retention mechanisms on the accuracy of activity coefficients at infinite dilution for 1-butyl-3-methylimidazolium octyl sulfate and 1-ethyl-3-methylimidazolium tosylate, phase loading studies of the net retention volume per gram of packing as a function of the percent phase loading were used. It is shown that most of the solutes are retained largely by partition with a small contribution from adsorption on 1-butyl-3-methylimidazolium octyl sulfate and that the n-alkanes are retained predominantly by interfacial adsorption on 1-ethyl-3-methylimidazolium tosylate.

  11. Ionic-liquid-assisted synthesis of YF{sub 3} with different crystalline phases and morphologies

    SciTech Connect

    Zhong Haoxiang; Hong Jianming; Cao Xiaofeng; Chen Xuetai Xue Ziling

    2009-03-05

    YF{sub 3} with different crystalline phases and morphologies have been prepared via a facile hydrothermal route assisted by imidazolium ionic liquids 1-butyl-3-methylimidazolium tetrafluoroborate (C{sub 4}mimBF{sub 4}) or 1-butyl-3-methylimidazolium hexafluorophosphate (C{sub 4}mimPF{sub 6}). The microstructures and morphologies of YF{sub 3} particles were characterized by X-ray powder diffraction, X-ray photoelectron spectra (XPS), transmission electron microscopy (TEM), high resolution electron microscopy (HRTEM) and field emission scanning electron microscopy (FESEM). Cubic and orthorhombic YF{sub 3} were selectively synthesized by adjusting the molar ratio of the reagents and using C{sub 4}mimBF{sub 4} as the fluoride source, while only orthorhombic YF{sub 3} was obtained using C{sub 4}mimPF{sub 6}, indicating that the crystalline phases and morphologies of the products were significantly influenced by fluoride source and reaction media.

  12. Spectroscopic properties and amplified spontaneous emission of fluorescein laser dye in ionic liquids as green media

    NASA Astrophysics Data System (ADS)

    AL-Aqmar, Dalal M.; Abdelkader, H. I.; Abou Kana, Maram T. H.

    2015-09-01

    The use of ionic liquids (ILs) as milieu materials for laser dyes is a promising field and quite competitive with volatile organic solvents and solid state-dye laser systems. This paper investigates some photo-physical parameters of fluorescein dye incorporated into ionic liquids; 1-Butyl-3-methylimidazolium chloride (BMIM Cl), 1-Butyl-3-methylimidazolium tetrachloroaluminate (BMIM AlCl4) and 1-Butyl-3-methylimidazolium tetrafluoroborate (BMIM BF4) as promising host matrix in addition to ethanol as reference. These parameters are: absorption and emission cross-sections, fluorescence lifetime and quantum yield, in addition to the transition dipole moment, the attenuation length and oscillator strength were also investigated. Lasing characteristics such as amplified spontaneous emission (ASE), the gain, and the photostability of fluorescein laser dye dissolved in different host materials were assessed. The composition and properties of the matrix of ILs were found that it has great interest in optimizing the laser performance and photostability of the investigated laser dye. Under transverse pumping of fluorescein dye by blue laser diode (450 nm) of (400 mW), the initial ASE for dye dissolved in BMIM AlCl4 and ethanol were decreased to 39% and 36% respectively as time progressed 132 min. Relatively high efficiency and high fluorescence quantum yield (11.8% and 0.82% respectively) were obtained with good photostability in case of fluorescein in BMIM BF4 that was decreased to ∼56% of the initial ASE after continuously pumping with 400 mW for 132 min.

  13. CO2 as a regulator for the controllable preparation of highly dispersed chitosan-supported Pd catalysts in ionic liquids.

    PubMed

    Xue, Zhimin; Sun, Xiaofu; Li, Zhonghao; Mu, Tiancheng

    2015-07-11

    A controllable synthetic route has been developed for the preparation of chitosan supported Pd catalysts in an ionic liquid, 1-butyl-3-methylimidazolium acetate ([Bmim]OAc), by using compressed CO2 as the anti-solvent and regulator. It was found that the dispersion of Pd particles on chitosan and the catalytic activity of the as-prepared catalysts for the hydrogenation of styrene could be tuned by changing the pressure of CO2.

  14. Lithium ion conductive behavior of TiO2 nanotube/ionic liquid matrices

    PubMed Central

    2014-01-01

    A series of TiO2 nanotube (TNT)/ionic liquid matrices were prepared, and their lithium ion conductive properties were studied. SEM images implied that ionic liquid was dispersed on the whole surface of TNT. Addition of TNT to ionic liquid (1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide (BMImTFSA)) resulted in significant increase of ionic conductivity. Furthermore, lithium transference number was also largely enhanced due to the interaction of anion with TNT. Vogel-Fulcher-Tammann parameter showed higher carrier ion number for TNT/BMImTFSA in comparison with BMImTFSA. PMID:25313300

  15. Amplified electrochemical sensor employing CuO/SWCNTs and 1-butyl-3-methylimidazolium hexafluorophosphate for selective analysis of sulfisoxazole in the presence of folic acid.

    PubMed

    Karimi-Maleh, Hassan; Amini, Fatemeh; Akbari, Ahmad; Shojaei, Moein

    2017-06-01

    In the present work, CuO nanoparticle decorated on single wall carbon nanotubes (CuO/SWCNTs) nanocomposite was successfully synthesized by chemical precipitation method and used for modification of carbon paste electrode (CPE) in the presence of 1-butyl-3-methylimidazolium hexafluorophosphate (1-B-3-MIHFP) liquid as binder. The novel voltammetric sensor was used as first electrochemical sensor for determination of sulfisoxazole (SFX). CuO/SWCNTs nanocomposite characterized by scanning electron microscopy (SEM) and X-ray powder diffraction (XRD) methods. Voltammetric methods such as cyclic voltammetry, square wave voltammetry (SWV), electrochemical impedance spectroscopy (EIS) and chronoamperometry were performed to assess the electrochemical performance of CuO/SWCNTs/1-B-3-MIHFP/CPE towards SFX in aqueous solution. The voltammetric obtained data confirm the significant enhancement of oxidation current and reduction overvoltage for electro-oxidation of SFX at a surface of CuO/SWCNTs/1-B-3-MIHFP/CPE. The square wave voltammetric response shows the linear increment of oxidation signals with an increase in the concentration of SFX in the range of 0.08-650μM with limit of detection 0.04μM. Using CuO/SWCNTs/1-B-3-MIHFP/CPE the SFX and folic acid peaks are separated ca. 0.72 and 0.895V, respectively; hence SFX can be detected in the presence of folic acid. Finally, the CuO/SWCNTs/1-B-3-MIHFP/CPE was used as high sensitive tools for analysis of SFX and folic acid in real samples.

  16. Effect of the physicochemical properties of binary ionic liquids on lipase activity and stability.

    PubMed

    Yao, Peipei; Yu, Xinxin; Huang, Xirong

    2015-01-01

    In the present study, the lipase-catalyzed hydrolysis of p-nitrophenyl butyrate is used as a model reaction to determine the activity and stability of Candida rugosa lipase in binary ionic liquids (ILs). The binary ILs consist of hydrophobic 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim]PF6) and a small amount of hydrophilic 1-butyl-3-methylimidazolium nitrate ([Bmim]NO3) or 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([Bmim]CF3SO3) or 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF4). The activity and the stability of lipase are first correlated with the physicochemical properties of the binary ILs. In the three binary IL systems, both the hydrophilicity and the polarity of the systems increase with the increase of the content of hydrophilic ILs (HILs). At a fixed concentration of HIL, they vary in a descending order of [Bmim]PF6/[Bmim]NO3>[Bmim]PF6/[Bmim]CF3SO3>[Bmim]PF6/[Bmim]BF4. This order is in contrast with the order of the lipase conformation stability, i.e., the higher the polarity of ILs, the more unstable the lipase conformation. However, both the activity and the stability of lipase depend on the type and the content of the HIL in binary ILs, showing a complex dependency. Analysis shows that the catalytic performance of lipase in the binary ILs is affected not only by the direct influence of the ILs on lipase conformation, but also through their indirect influence on the physicochemical properties of water. The present study helps to explore binary IL mixtures suitable for lipase-based biocatalysis.

  17. Surface Nanocrystallization of an Ionic Liquid

    SciTech Connect

    Jeon, Yoonnam; Vaknin, David; Bu, Wei; Sung, Jaeho; Ouchi, Yukio; Sung, Woongmo; Kim, Doseok

    2012-03-26

    Surface crystallization at the vapor-liquid interface of the ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) is observed in synchrotron x-ray diffraction studies. Sharp Bragg reflections emerge in grazing-angle x-ray diffraction patterns 37 C above the bulk melting temperature, indicating the presence of a long-range ordered phase at the surface in coexistence with the bulk parent liquid. The unique structure of the vapor-liquid interface where butyl chains attached to the cations are expelled to the vapor side facilitates interionic electrostatic interactions that lead to the crystallization. Our results demonstrate the complexity of ionic-liquid structure with their tendency to spontaneously phase separate into nanodomains with finite correlation lengths in coexistence with the liquid phase. By virtue of interfacial boundary conditions, these nanodomains grow laterally to form quasi-two-dimensional crystals.

  18. Structural study of lysozyme in two ionic liquids at cryogenic temperature

    NASA Astrophysics Data System (ADS)

    Yoshimura, Yukihiro; Takekiyo, Takahiro; Mori, Takahiro

    2016-11-01

    We have investigated the structure and activity of chicken egg-white lysozyme in aqueous solutions of two typical ionic liquids, 1-butyl-3-methylimidazolium chloride and ethylammonium nitrate, at cryogenic temperature. An increase in structural disorder due to the unfolding and a decrease in the α-helical structure of lysozyme were noticeable upon glass formation. However, a decrease in the structural stability after cooling was less than that before cooling. The secondary and tertiary structures showed good reversibility upon cooling to 77 K and then reverting back to ambient temperature. We discussed an influence of a cooling upon the structure in aqueous ionic liquid solutions.

  19. Electrodeposition of Three Dimensionally Ordered Macroporous Germanium from Two Different Ionic Liquids.

    PubMed

    Hao, Jian; Zhao, Jiupeng; Zhang, Yiwen; An, Xiaokun; Liu, Xin; Li, Yao; Endres, Frank

    2016-01-01

    Three dimensionally ordered macroporous (3DOM) Ge films have been made via ordered polystyrene (PS) templates by electrodeposition from ionic liquids 1-Butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) amide and 1-Ethyl-3-methylimidazolium tris (pentafluoroethyl) trifluorophosphate at room temperature. We discuss the possibility of obtaining high quality 3DOM Ge films from two different ionic liquids by the simple and inexpensive template-assisted electrochemical pathway. Scanning electron microscopy confirms the quality of the samples, and the optical measurements demonstrate that 3DOM Ge made electrochemically shows photonic crystal behavior. Such a material has the potential to make 3DOM Ge feasible for electrical, optical applications and for photonic crystal solar cells.

  20. Templated electrodeposition of silver nanowires in a nanoporous polycarbonate membrane from a nonaqueous ionic liquid electrolyte

    NASA Astrophysics Data System (ADS)

    Kazeminezhad, I.; Barnes, A. C.; Holbrey, J. D.; Seddon, K. R.; Schwarzacher, W.

    2007-03-01

    Template electrodeposition has been used to prepare a wide range of nanostructures but has generally been restricted to aqueous electrolytes. We report the deposition of silver nanowires in a commercial nuclear track-etched polycarbonate template from the nonaqueous ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) using silver electrochemically dissolved from the anode. Transmission electron microscopy (TEM) shows that the nanowires have a very high aspect ratio with an average diameter of 80 nm and length of 5 μm. Ionic liquid electrolytes should greatly extend the range of metals that can be electrodeposited as nanowires using templates.

  1. Determination of rifaximin in rat serum by ionic liquid based dispersive liquid-liquid microextraction combined with RP-HPLC.

    PubMed

    Rao, Ramisetti Nageswara; Vali, Rajavarapu Mastan; Rao, Alamanda Vara Prasada

    2012-08-01

    An efficient and environmental friendly ionic liquid based dispersive liquid-liquid microextraction procedure was optimized for determination of rifaximin in rat serum by reverse phase high-performance liquid chromatography. The effect of ionic liquids, dispersive solvents, extractant/disperser ratio, and salt concentrations on sample recovery and enrichment factors were studied. Among the five ionic liquids studied in the present investigation, 1-butyl-3-methylimidazolium hexafluorophosphate was found to be most effective for extraction of rifaximin. The recovery was found to be more than 98% using 1-butyl-3-methylimidazolium hexafluorophosphate and methanol as extraction and dispersive solvents, at an extractant/disperser ratio of 0.43. The recovery was further enhanced to 99.5% by the addition of 5.0% NaCl solution. A threefold enhancement in detection limit was achieved when compared to protein precipitation. The ionic liquid containing the extracted rifaximin was directly injected into HPLC system. The linear relationship was observed in the range of 0.03-10.0 μg/mL with the correlation coefficient (r(2)) 0.9998. Limits of detection and quantification were found to be 0.01 and 0.03 μg/mL, respectively. The relative standard deviation was 2.5%. The method was validated and applied to study pharmacokinetics of rifaxmin in rat serum.

  2. Fabrication and Characterization of Polysaccharide Ion Gels with Ionic Liquids and Their Further Conversion into Value-Added Sustainable Materials

    PubMed Central

    Takada, Akihiko; Kadokawa, Jun-ichi

    2015-01-01

    A review of the fabrication of polysaccharide ion gels with ionic liquids is presented. From various polysaccharides, the corresponding ion gels were fabricated through the dissolution with ionic liquids. As ionic liquids, in the most cases, 1-butyl-3-methylimidazolium chloride has been used, whereas 1-allyl-3methylimidazolium acetate was specifically used for chitin. The resulting ion gels have been characterized by suitable analytical measurements. Characterization of a pregel state by viscoelastic measurement provided the molecular weight information. Furthermore, the polysaccharide ion gels have been converted into value-added sustainable materials by appropriate procedures, such as exchange with other disperse media and regeneration. PMID:25793912

  3. How Does the Addition of a Third Ion Affect the Molecular Interactions and the Thermodynamic Properties of Acetate-Based Ionic Liquids?

    PubMed

    Otero, I; Lepre, L F; Dequidt, A; Husson, P; Costa Gomes, M F

    2017-10-06

    The effect of the addition of a third ion to the ionic liquid 1-butyl-3-methylimidazolium acetate [C4C1Im][OAc] was studied through the measurement of the enthalpy of mixing and of the excess molar volume of its mixtures with 1-butyl-3-methylimidazolium trifluoroacetate [C4C1Im][CF3CO2], 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [C4C1Im][NTf2], and tetrabutylphosphonium acetate [P4444][OAc]. Negative enthalpies of mixing (ΔmixH < 0) and positive excess molar volumes (V(E) > 0) were observed in all cases. The infrared and NMR studies of the pure ionic liquids and their mixtures show that the presence of a third ion with a weaker affinity with the common counterion contributes to prevailing the more favorable hydrogen-bond, herein always between the imidazolium cation and the acetate anion. Both radial and spatial distribution functions calculated by molecular simulation confirm this behavior. The remarkable enhancement of the viscosities of the [C4C1Im][OAc] + [P4444][OAc] mixtures could be discussed in light of the calculated friction coefficients.

  4. Microwave-assisted separation of ionic liquids from aqueous solution of ionic liquids.

    PubMed

    Ha, Sung Ho; Mai, Ngoc Lan; Koo, Yoon-Mo

    2010-12-03

    Microwave-assisted separation has been applied to recover ionic liquid (IL) from its aqueous solution as an efficient method with respect to time and energy compared to the conventional vacuum distillation. Hydrophilic ILs such as 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF(4)]), 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([Bmim][TfO]) and 1-ethyl-3-methylimidazolium methylsulfate ([Emim][MS]) could be recovered in 6 min from the mixture of ILs and water (1:1, w/w) under microwave irradiation at constant power of 10 W while it took at least 240 min to obtain ILs containing same water content (less than 0.5 wt%) by conventional vacuum oven at 363.15 K with 90 kPa of vacuum pressure. Energy consumptions per gram of evaporated water from the homogeneous mixture of hydrophilic ILs and water (1:1, w/w) by microwave-assisted separation were at least 52 times more efficient than those in conventional vacuum oven. It demonstrated that microwave-assisted separation could be used for complete recovery of ILs in sense of time and energy as well as relevant purity.

  5. Oxidative desulfurization of dibenzothiophene from model oil using ionic liquids as extracting agent

    NASA Astrophysics Data System (ADS)

    Taha, Mohd F.; Atikah, N.; Chong, F. K.; Shaharun, Maizatul S.

    2012-09-01

    The oxidative desulfurization of dibenzothiophene (DBT) from model oil (in n-dodecane) was carried out using ionic liquid as the extractant and catalyst, and hydrogen peroxide (H2O2) in combination with acetic acid (CH3COOH) and sulphuric acid (H2SO4) as the oxidant. The ionic liquids used were 1-butyl-3-methylimidazolium octyl sulphate ([Bmim][OcSO4]) and 1-butyl-3-methylimidazolium acetate ([Bmim][Ac]). The effect of the amounts of H2O2 on oxidative desulphurization of model oil was first investigated without the usage of ionic liquids at room temperature. The results indicate that greater amount of H2O2 give higher desulfurization and the maximum desulfurization in this study, i.e. 34 %, was occurred when the molar ratio of H2O2 to sulfur was 5:1. With the usage of ionic liquid and the molar ratio of 5:1 (H2O2:sulfur), the efficiency of DBT removal from model oil was increased significantly in terms of percent removal and removal time. Ionic liquid of [Bmim][OcSO4] performed better than [Bmim][Ac] with 72 % DBT removal. When molar ratio of H2O2 to sulphur was 5:1, volume ratio of ionic liquid to model oil was 1:1 and mixing time was 60 min at room temperature. The results indicate the potential of ionic liquids as the extractant and catalyst for oxidative desulfurization of hydrocarbon fuels.

  6. A nonaqueous lyotropic liquid crystal fabricated by a polyoxyethylene amphiphile in protic ionic liquid.

    PubMed

    Ma, Fumin; Chen, Xiao; Zhao, Yurong; Wang, Xudong; Li, Qiuhong; Lv, Chao; Yue, Xiu

    2010-06-01

    The aggregation behaviors of oleyl polyoxyethylene (10) ether, Brij 97, in room temperature ionic liquids, ethylammonium nitrate (EAN), pyrrolidinium nitrate ([Pyrr][NO(3)]), ethylammonium butyrate (EAB), 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim][PF(6)]), and 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF(4)]), have been investigated. Only in the Brij 97/EAN binary system is the hexagonal liquid crystalline phase formed, and its ordering is found to decrease with increasing temperature. The lattice spacing values measured from the small-angle X-ray scattering (SAXS) shrink with reduction of ionic liquid content at room temperature. The general rules for aggregate formation in these ionic liquids are discussed and compared with that in water. A degraded ability to produce the ordered self-assembly of Brij 97 from H(2)O to EAN to [Bmim][PF(6)], [Bmim][BF(4)], [Pyrr][NO(3)], and EAB is found and analyzed based on the molecular packing and Gordon parameters and also hydrogen-bonding or solvophobic interactions. Steady-shear rheological measurements combined with the frequency sweep data indicate the highly viscoelastic nature of this liquid crystalline phase.

  7. Ionic liquids-lithium salts pretreatment followed by ultrasound-assisted extraction of vitexin-4″-O-glucoside, vitexin-2″-O-rhamnoside and vitexin from Phyllostachys edulis leaves.

    PubMed

    Hou, Kexin; Chen, Fengli; Zu, Yuangang; Yang, Lei

    2016-01-29

    An efficient method for the extraction of vitexin, vitexin-4″-O-glucoside, and vitexin-2″-O-rhamnoside from Phyllostachys edulis leaves comprises heat treatment using an ionic liquid-lithium salt mixture (using 1-butyl-3-methylimidazolium bromide as the solvent and lithium chloride as the additive), followed by ultrasound-assisted extraction. To obtain higher extraction yields, the effects of the relevant experimental parameters (including heat treatment temperature and time, relative amounts of 1-butyl-3-methylimidazolium bromide and lithium chloride, power and time of the ultrasound irradiation, and the liquid-solid ratio) are evaluated and response surface methodology is used to optimize the significant factors. The morphologies of the treated and untreated P. edulis leaves are studied by scanning electron microscopy. The improved extraction method proposed provides high extraction yield, good repeatability and precision, and has wide potential applications in the analysis of plant samples.

  8. Extraction of ranitidine and nizatidine with using imidazolium ionic liquids prior spectrophotometric and chromatographic detection.

    PubMed

    Kiszkiel, Ilona; Starczewska, Barbara; Leśniewska, Barbara; Późniak, Patrycja

    2015-03-15

    A new extraction medium was proposed for liquid-liquid extraction of the histamine H2 receptor antagonists ranitidine (RNT) and nizatidine (NZT). The ionic liquids with low vapor pressure and favorable solvating properties for a range of compounds such as 1-butyl-3-methylimidazolium hexafluorophosphate [C4mim][PF6] and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [C4mim][Tf2N] were tested for isolation of analytes. The extraction parameters of RNT and NZT, namely, amount of ionic liquid, pH of sample solution, shaking and centrifugation time were optimized. The isolation processes were performed with 1 mL of the ionic liquids. The extracted samples (pH values near 4) were shaken at 1750 rpm. The influence of interfering substances on the efficiency of extraction process was also studied. Methods for the histamine H2 receptor antagonists (ranitidine and nizatidine) determination after their separation using imidazolium ionic liquids by high performance liquid chromatography (HPLC) combined with UV spectrophotometry were developed. The application of ionic liquids in extraction step allows for selective isolation of analytes from aqueous matrices and their preconcentration. The above methods were applied to the determination of RNT and NZT in environmental samples (river water and wastewater after treatment).

  9. High viscosity of imidazolium ionic liquids with the hydrogen sulfate anion: a Raman spectroscopy study.

    PubMed

    Ribeiro, Mauro C C

    2012-06-21

    Ionic liquids based on 1-alkyl-3-methylimidazolium cations and the hydrogen sulfate (or bisulfate) anion, HSO(4)(-), are much more viscous than ionic liquids with alkyl sulfates, RSO(4)(-). The structural origin of the high viscosity of HSO(4)(-) ionic liquids is unraveled from detailed comparison of the anion Raman bands in 1-ethyl-3-methylimidazolium hydrogen sulfate and 1-butyl-3-methylimidazolium hydrogen sulfate with available data for simple HSO(4)(-) salts in crystalline phase, molten phase, and aqueous solution. Two Raman bands at 1046 and 1010 cm(-1) have been assigned as symmetric stretching modes ν(s)(S═O) of HSO(4)(-), the latter being characteristic of chains of hydrogen-bonded anions. The intensity of this component increases in the supercooled liquid phase. For comparison purposes, Raman spectra of 1-ethyl-3-methylimidazolium ethyl sulfate and 1-butyl-3-methylimidazolium methyl sulfate have been also obtained. There is no indication of difference in the strength of hydrogen bond interactions of imidazolium cations with HSO(4)(-) or RSO(4)(-) anions. Raman spectra at high pressures, up to 2.6 GPa, are also discussed. Raman spectroscopy provides evidence that hydrogen-bonded anions resulting in anion-anion interaction is the reason for the high viscosity of imidazolium ionic liquids with HSO(4)(-). If the ionic liquid is exposed to moisture, these structures are disrupted upon absorption of water from the atmosphere.

  10. Dissolution of cellulose in ionic liquid: A review

    NASA Astrophysics Data System (ADS)

    Mohd, N.; Draman, S. F. S.; Salleh, M. S. N.; Yusof, N. B.

    2017-02-01

    Dissolution of cellulose with ionic liquids (IL) and deep eutectic solvent (DES) lets the comprehensive dissolution of cellulose. Basically, cellulose can be dissolved, in some hydrophilic ionic liquids, such as 1-butyl-3-methylimidazolium chloride (BMIMCl) and 1-allyl-3-methylimidazolium chloride (AMIMCl). Chloride based ionic liquids are suitable solvents for cellulose dissolution. Although the ILs is very useful in fine chemical industry, its application in the pharmaceutical and food industry have been very limited due to issues with toxicity, purity, and high cost. Seeing to these limitations, new green alternative solvent which is DES was used. This green solvents, may be definitely treated as the next-generation reagents for more sustainable industrial development. Thus, this review aims to discuss the dissolution of cellulose either with ionic liquids or DES and its application.

  11. Radiation stability of some room temperature ionic liquids

    NASA Astrophysics Data System (ADS)

    Jagadeeswara Rao, Ch.; Venkatesan, K. A.; Tata, B. V. R.; Nagarajan, K.; Srinivasan, T. G.; Vasudeva Rao, P. R.

    2011-05-01

    Radiation stability of some room temperature ionic liquids (RTILs) that find useful electrochemical applications in nuclear fuel cycle has been evaluated. The ionic liquids such as protonated betaine bis(trifluoromethylsulfonyl)imide (HbetNTf 2), aliquat 336 (tri-n-octlymethylammonium chloride), 1-butyl-3-methylimidazolium chloride (bmimCl), 1-hexyl-3-methylimidazolium chloride (hmimCl), N-butyl-N-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (BMPyNTf 2) and N-methyl-N-propylpiperidinium bis(trifluoromethylsulfonyl)imide (MPPiNTf 2) have been irradiated to various absorbed dose levels, up to 700 kGy. The effect of gamma radiation on these ionic liquids has been evaluated by determining the variations in the physical properties such as color, density, viscosity, refractive index and electrochemical window. The changes in density, viscosity and refractive index of these ionic liquids upon irradiation were insignificant; however, the color and electrochemical window varied significantly with increase of absorbed dose.

  12. Femtosecond Raman-Induced Kerr Effect Study of Temperature-Dependent Intermolecular Dynamics in Imidazolium-Based Ionic Liquids: Effects of Anion Species and Cation Alkyl Groups.

    PubMed

    Kakinuma, Shohei; Ishida, Tateki; Shirota, Hideaki

    2017-01-12

    The temperature dependence of the intermolecular vibrational dynamics in imidazolium-based ionic liquids (ILs) with 10 different anions was studied by femtosecond Raman-induced Kerr effect spectroscopy. For all ILs investigated in this study, the intensity in the low-frequency region below 50 cm(-1) increases, and the spectral density in the high-frequency region above 80 cm(-1) decreases (and shows a redshift) with increasing temperature. The first phenomenon would be attributed to the activation of the translational vibrational motions, whereas the second one is ascribed to the slowing librational motion of the imidazolium ring with increasing temperature. Calculated spectra of the density of states for the intermolecular vibrations of 1-butyl-3-methylimidazolium hexafluorophosphate, which is one of the experiment samples studied here, obtained by molecular dynamics simulation agreed well with the experimental results and confirmed the spectral assignments. When we compared the difference spectra between spectra measured at various temperatures and the spectrum measured at 293 K, a clear difference was found in the ∼50 cm(-1) region of the Kerr spectra of 1-butyl-3-methylimidazolium thiocyanate and 1-butyl-3-methylimidazolium dicyanamide from those of the other ILs. The difference might have originated from the librational motions of the corresponding anions. We also compared the temperature-dependent Kerr spectra of hexafluorophosphate salts of 1-butyl-3-methylimidazolium, 1-hexyl-3-methylimidazolium, and 1-heptyl-3-methylimidazolium cations. These ILs showed a similar temperature dependence, which was not affected by the alkyl group length. The temperature-dependent viscosities and glass transition temperatures of the ILs were also estimated to determine their fragilities.

  13. Determination of triazine herbicides in juice samples by microwave-assisted ionic liquid/ionic liquid dispersive liquid-liquid microextraction coupled with high-performance liquid chromatography.

    PubMed

    Su, Rui; Li, Dan; Wu, Lijie; Han, Jing; Lian, Wenhui; Wang, Keren; Yang, Hongmei

    2017-07-01

    A novel microextraction method, termed microwave-assisted ionic liquid/ionic liquid dispersive liquid-liquid microextraction, has been developed for the rapid enrichment and analysis of triazine herbicides in fruit juice samples by high-performance liquid chromatography. Instead of using hazardous organic solvents, two kinds of ionic liquids, a hydrophobic ionic liquid (1-hexyl-3-methylimidazolium hexafluorophosphate) and a hydrophilic ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate), were used as the extraction solvent and dispersion agent, respectively, in this method. The extraction procedure was induced by the formation of cloudy solution, which was composed of fine drops of 1-hexyl-3-methylimidazolium hexafluorophosphate dispersed entirely into sample solution with the help of 1-butyl-3-methylimidazolium tetrafluoroborate. In addition, an ion-pairing agent (NH4 PF6 ) was introduced to improve recoveries of the ionic liquid phase. Several experimental parameters that might affect the extraction efficiency were investigated. Under the optimum experimental conditions, the linearity for determining the analytes was in the range of 5.00-250.00 μg/L, with the correlation coefficients of 0.9982-0.9997. The practical application of this effective and green method is demonstrated by the successful analysis of triazine herbicides in four juice samples, with satisfactory recoveries (76.7-105.7%) and relative standard deviations (lower than 6.6%). In general, this method is fast, effective, and robust to determine triazine herbicides in juice samples. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Recombination of photogenerated lophyl radicals in imidazolium-based ionic liquids.

    PubMed

    Strehmel, Veronika; Wishart, James F; Polyansky, Dmitry E; Strehmel, Bernd

    2009-12-07

    Laser flash photolysis is applied to study the recombination reaction of lophyl radicals in ionic liquids in comparison with dimethylsulfoxide as an example of a traditional organic solvent. The latter exhibits a similar micropolarity as the ionic liquids. The ionic liquids investigated are 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (1), 1-hexyl-3-methylimidazolium hexafluorophosphate (2), and 1-butyl-3-methylimidazolium tetafluoroborate (3). The recombination of the photolytic generated lophyl radicals occur significantly faster in the ionic liquids than expected from their macroscopic viscosities and is a specific effect of these ionic liquids. On the other hand, this reaction can be compared with the macroscopic viscosity in the case of dimethylsulfoxide. Activation parameters obtained for lophyl radical recombination suggest different, anion-dependent mechanistic effects. Quantum chemical calculations based on density functional theory provide a deeper insight of the molecular properties of the lophyl radical and its precursor. Thus, excitation energies, spin densities, molar volumes, and partial charges are calculated. Calculations show a spread of spin density over the three carbon atoms of the imidazolyl moiety, while only low spin density is calculated for the nitrogens.

  15. Recombination of Photogenerated Lophyl Radicals in Imidazolium-Based Ionic Liquids

    SciTech Connect

    Strehmel, V.; Wishart, J.; Polyansky, D.E.; Strehmel, B.

    2009-10-20

    Laser flash photolysis is applied to study the recombination reaction of lophyl radicals in ionic liquids in comparison with dimethylsulfoxide as an example of a traditional organic solvent. The latter exhibits a similar micropolarity as the ionic liquids. The ionic liquids investigated are 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (1), 1-hexyl-3-methylimidazolium hexafluorophosphate (2), and 1-butyl-3-methylimidazolium tetafluoroborate (3). The recombination of the photolytic generated lophyl radicals occur significantly faster in the ionic liquids than expected from their macroscopic viscosities and is a specific effect of these ionic liquids. On the other hand, this reaction can be compared with the macroscopic viscosity in the case of dimethylsulfoxide. Activation parameters obtained for lophyl radical recombination suggest different, anion-dependent mechanistic effects. Quantum chemical calculations based on density functional theory provide a deeper insight of the molecular properties of the lophyl radical and its precursor. Thus, excitation energies, spin densities, molar volumes, and partial charges are calculated. Calculations show a spread of spin density over the three carbon atoms of the imidazolyl moiety, while only low spin density is calculated for the nitrogens.

  16. Synthesis of (S)-ricinoleic acid and its methyl ester with the participation of ionic liquid.

    PubMed

    Kula, Józef; Bonikowski, Radoslaw; Szewczyk, Malgorzata; Ciolak, Kornelia

    2014-10-01

    (R)-ricinoleic acid methyl ester obtained from commercial castor oil was transformed in a three-step procedure into its S-enantiomer in overall 36% yield using ionic liquid (1-butyl-3-methylimidazolium acetate) in the key step process. The developed procedure provides easy access to (S)-ricinoleic acid and its methyl ester of over 95% enantiomeric excess. Optical rotations of the newly obtained compounds as well as their chromatographic and spectral characteristics are provided and discussed in the context of enantiopurity both of the substrate material and the final products.

  17. Hydrodynamic sono-voltammetry of ferrocene in [Tf2N]- based ionic liquid media.

    PubMed

    Costa, Cédric; Doche, Marie-Laure; Hihn, Jean-Yves; Bisel, Isabelle; Moisy, Philippe; Lévêque, Jean-Marc

    2010-02-01

    The present work deals with the hydrodynamic behavior of several room-temperature ionic liquids presenting the same bis(trifluoromethanesulfonyles)imide anion, associated with four different cations: 1-butyl-3-methylimidazolium, 1-octyl-3-methylimidazolium, N-trimethyl-N-propylammonium and 1-butyl-1-methylpyrrolidinium cations. Steady state voltammetry was used as an electrochemical technique to characterize mass transfer in both silent and sonicated conditions, using a rotating disk electrode. Results obtained in RTILs media are compared to those acquired in synthetic solutions of controlled viscosity, in order to develop a better understanding of the phenomena involved in such media.

  18. Microregion detection of ionic liquid microemulsions.

    PubMed

    Gao, Yanan; Wang, Suqing; Zheng, Liqiang; Han, Shuaibing; Zhang, Xuan; Lu, Deming; Yu, Li; Ji, Yongqiang; Zhang, Gaoyong

    2006-09-15

    Nonaqueous ionic liquid (IL) microemulsion consisting of IL, 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF(4)), surfactant TX-100, and toluene was prepared and the phase behavior of the ternary system was investigated. Electrical conductivity measurement was used for investigating the microregions of the nonaqueous IL microemulsions. On the basis of the percolation theory, the bmimBF(4)-in-toluene (IL/O), bicontinuous, and toluene-in-bmimBF(4) (O/IL) microregions of the microemulsions were successfully identified using insulative toluene as the titration phase. However, this method was invalid when conductive bmimBF(4) acted as the titration phase. The microregions obtained by conductivity measurements were further proved by electrochemical cyclic voltammetry experiments. The results indicated that the conductivity method was feasible for identifying microstructures of the nonaqueous IL microemulsions.

  19. The vapour of imidazolium-based ionic liquids: a mass spectrometry study.

    PubMed

    Deyko, A; Lovelock, K R J; Licence, P; Jones, R G

    2011-10-06

    Eight common dialkylimidazolium-based ionic liquids have been successfully evaporated in ultra-high vacuum and their vapours analysed by line of sight mass spectrometry using electron ionisation. The ionic liquids investigated were 1-alkyl-3-methylimidazolium bis[(trifluoromethane)sulfonyl]imide, [C(n)C(1)Im][Tf(2)N] (where n = 2, 4, 6, 8), 1-alkyl-3-methylimidazolium tetrafluoroborate, [C(n)C(1)Im][BF(4)] (where n = 4, 8), 1-butyl-3-methylimidazolium octylsulfate, [C(4)C(1)Im][C(8)OSO(3)] and 1-butyl-3-methylimidazolium tetrachloroferrate, [C(4)C(1)Im][FeCl(4)]. All ionic liquids studied here evaporated as neutral ion pairs; no evidence of decomposition products in the vapour phase were observed. Key fragment cations of the ionised vapour of the ionic liquids are identified. The appearance energies, E(app), of the parent cation were measured and used to estimate the ionisation energies, E(i), for the vapour phase neutral ion pairs. Measured ionisation energies ranged from 10.5 eV to 13.0 eV. Using both the identity and E(app) values, the fragmentation pathways for a number of fragment cations are postulated. It will be shown that the enthalpy of vaporisation, Δ(vap)H, can successfully be measured using more than one fragment cation, although caution is required as many fragment cations can also be formed by ionisation of decomposition products.

  20. Solvent extraction separation of Th-227 and Ac-225 in room temperature ionic liquids

    SciTech Connect

    Bell, Jason R; Boll, Rose Ann; Dai, Sheng; Luo, Huimin

    2012-01-01

    The solvent extractions of Th-227 and Ac-225 from the aqueous phase into ionic liquids (ILs) were investigated by using N,N,N ,N - tetraoctyldiglycolamide (TODGA) or di(2-ethylhexyl)phosphoric acid (HDEHP) as an extractant. Four ionic liquids, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C4mim][NTf2]), 1-butyl-3-methylimidazolium bis(perfluoroethanesulfonyl)imide ([C4mim][BETI]), 1-butyl-2,3-trimethyleneimidazolium (trifluoromethanesulfonyl)imide [BuI5][NTf2], and 1-benzyl pyridinium bis(trifluoromethanesulfonyl)imide ([PhCH2Py][NTf2]) were used as extraction solvents for separation of Th-227 and Ac-225 in this study. Excellent extraction efficiencies and selectivities were found for Th-227/Ac-225 when HDEHP was used as an extractant in these ionic liquids. The effects of different extractant concentrations in ionic liquids and acidities of the aqueous phase on extraction efficiencies and selectivities of Th-227/Ac-225 are also presented in this article.

  1. The Highly Selective and Near-Quantitative Conversion of Glucose to 5-Hydroxymethylfurfural Using Ionic Liquids

    PubMed Central

    Eminov, Sanan; Brandt, Agnieszka; Wilton-Ely, James D. E. T.

    2016-01-01

    A number of ionic liquids have been shown to be excellent solvents for lignocellulosic biomass processing, and some of these are particularly effective in the production of the versatile chemical building block 5-hydroxymethylfurfural (HMF). In this study, the production of HMF from the simple sugar glucose in ionic liquid media is discussed. Several aspects of the selective catalytic formation of HMF from glucose have been elucidated using metal halide salts in two distinct ionic liquids, 1-butyl-3-methylimidazolium chloride and 1-butyl-3-methylimidazolium hydrogen sulfate as well as mixtures of these, revealing key features for accelerating the desired reaction and suppressing byproduct formation. The choice of ionic liquid anion is revealed to be of particular importance, with low HMF yields in the case of hydrogen sulfate-based salts, which are reported to be effective for HMF production from fructose. The most successful system investigated in this study led to almost quantitative conversion of glucose to HMF (90% in only 30 minutes using 7 mol% catalyst loading at 120°C) in a system which is selective for the desired product, has low energy intensity and is environmentally benign. PMID:27711238

  2. Interactions between dendrimers and ionic liquids revealed by pulsed field gradient and nuclear Overhauser effect NMR studies.

    PubMed

    Zhao, Libo; Li, Cai; Zhang, Jiahai; Wu, Qinglin; Xu, Tongwen; Cheng, Yiyun

    2012-06-21

    The host-guest interactions of cationic and anionic poly(amidoamine) (PAMAM) dendrimers with three ionic liquids including 1-butyl-3-methylimidazolium 2-(2-methoxyethoxy)ethyl sulfate ([BMIM][MDEGSO(4)]), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMIM][TFSI]), and trihexyltetradecylphosphonium bis((trifluoromethyl)sulfonyl)imide ([THTDP][TFSI]) were investigated by several NMR techniques such as (1)H and (19)F NMR, pulsed field gradient (PFG) NMR, and 2D nuclear Overhauser enhancement spectroscopy (NOESY). Anionic PAMAM dendrimer interacts with the ionic liquids via ionic interactions. However, almost no interaction is observed between cationic PAMAM dendrimer and the ionic liquids without pH adjustment. Besides, no inclusion formation between the PAMAM dendrimers and the ionic liquids is observed on the basis of NOE NMR studies. The interactions between dendrimers and ionic liquids are very different from those between dendrimers and surfactants or amphiphilic drugs. The results obtained from PFG and NOE studies provide new insights into dendrimer-based host-guest systems.

  3. Ionic liquid-based dispersive liquid-liquid microextraction followed by RP-HPLC determination of saquinavir in rat serum: application to pharmacokinetics.

    PubMed

    Ramisetti, Nageswara Rao; Nimmu, Narendra Varma; Challa, Gangu Naidu

    2014-12-01

    An ionic liquid-based dispersive liquid-liquid microextraction followed by RP-HPLC determination of the most commonly prescribed protease inhibitor, saquinavir, in rat plasma was developed and validated. The effects of different ionic liquids, dispersive solvents, extractant/disperser ratio and salt concentration on sample recovery and enrichment were studied. Among the ionic liquids investigated, 1-butyl-3-methylimidazolium hexafluorophosphate was found to be most effective for extraction of saquinavir from rat serum. The recovery was found to be 95% at an extractant/disperser ratio of 0.43 using 1-butyl-3-methylimidazolium hexafluorophosphate and methanol as extraction and dispersive solvents. The recovery was further enhanced to 99.5% by addition of 5.0% NaCl. A threefold enhancement in detection and quantification limits was achieved, at 0.01 and 0.03 µg/mL, compared with the conventional protein precipitation method. A linear relationship was observed in the range of 0.035-10.0 µg/mL with a correlation coefficient (r(2) ) of 0.9996. The method was validated and applied to study pharmacokinetics of saquinavir in rat serum.

  4. Dynamics of Loop 1 of Domain I in Human Serum Albumin WhenDissolved in Ionic Liquids

    SciTech Connect

    Page, Taylor; Kraut, Nadine; Page, Phillip; Baker, Gary A; Bright, Frank

    2009-01-01

    We report on the rotational reorientation dynamics associated with loop 1 of domain I within a large multidomain protein (human serum albumin, HSA) when it is dissolved in binary mixtures of ionic liquid (1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C4mim][Tf2N]), 1-butyl-3-methylimidazolium tetrafluoroborate ([C4mim][BF4]), or 1-butyl-3-methylimidazolium hexafluorophosphate ([C4mim][PF6])) and distilled deionized water (ddH2O) as a function of temperature and water loading. In IL/2% ddH2O (v/v) mixtures, loop 1 of domain I is more significantly denatured in comparison to the protein dissolved in aqueous solutions containing strong chemical denaturants (e.g., 8 M guanidine HCl (Gu HCl) or urea). As water loading increases, there is evidence for progressive refolding of loop 1 of domain I followed by recoupling with domains I, II, and III in the [C4mim][BF4]/ddH2O mixtures at 20 C. Above 30% (v/v) water, where domain I appears refolded, the Ac reporter molecule s semiangle steadily decreases from 35 to 20 with increasing water loading. From the perspective of domain I in HSA, this behavior is similar to the effects of dilution from 4 to 0 M Gu HCl in aqueous solution. Overall, these results lend insight into the tangle of biocatalytic and structural/dynamical mechanisms that enzymes may undergo in ionic liquid-based systems. It will be particularly motivating to extend this work to include enzyme-attuned ionic liquids shown to improve biocatalytic performance beyond that possible in the native (predominantly aqueous) setting.

  5. Synthesis of Novel Flower-Like Zn(OH)F via a Microwave-Assisted Ionic Liquid Route and Transformation into Nanoporous ZnO by Heat Treatment

    PubMed Central

    2009-01-01

    Zinc hydroxide fluoride (Zn(OH)F) with novel flower-like morphology has been prepared via a microwave-assisted ionic liquid route. The flower-like Zn(OH)F particle has six petals and every petal is composed of lots of acicular nano-structure. Nanoporous ZnO is obtained by thermal decomposition of as-prepared Zn(OH)F in air, and the flower-like morphology is well retained. In the process of synthesis, ionic liquid 1-Butyl-3-methylimidazolium tetrafluoroborate is used as both the reactant and the template. PMID:20651922

  6. Synthesis of Novel Flower-Like Zn(OH)F via a Microwave-Assisted Ionic Liquid Route and Transformation into Nanoporous ZnO by Heat Treatment

    NASA Astrophysics Data System (ADS)

    Song, Jia-Kui; Zheng, Ming-Bo; Yang, Zhen-Jiang; Chen, Hui-Qin; Wang, Hai-Yan; Liu, Jin-Song; Ji, Guang-Bin; Zhang, Hai-Qian; Cao, Jie-Ming

    2009-12-01

    Zinc hydroxide fluoride (Zn(OH)F) with novel flower-like morphology has been prepared via a microwave-assisted ionic liquid route. The flower-like Zn(OH)F particle has six petals and every petal is composed of lots of acicular nano-structure. Nanoporous ZnO is obtained by thermal decomposition of as-prepared Zn(OH)F in air, and the flower-like morphology is well retained. In the process of synthesis, ionic liquid 1-Butyl-3-methylimidazolium tetrafluoroborate is used as both the reactant and the template.

  7. Ionic liquids for improving the extraction of NSAIDs in water samples using dispersive liquid-liquid microextraction by high performance liquid chromatography-diode array-fluorescence detection.

    PubMed

    Toledo-Neira, Carla; Álvarez-Lueje, Alejandro

    2015-03-01

    A rapid, sensitive and efficient analytical method based on the use of ionic liquids for determination of non-steroidal anti-inflammatory drugs (NSAIDs) in water samples was developed. High-performance liquid chromatography equipped with a diode array and fluorescence detector was used for quantification of ketoprofen, ibuprofen and diclofenac in tap and river water samples. This new method relies on the use of two ionic liquids with multiple functionalities: one functions as an extraction solvent (1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]), and the other changes the polarity in the aqueous medium (1-butyl-3-methylimidazolium tetrafluoroborate, ([BMIM][BF4]). Factors such as the type and volume of the ILs and dispersive solvent, sample volume, and centrifugation time were investigated and optimized. The optimized method exhibited good precision, with relative standard deviation values between 2% and 3%, for the three NSAIDs. Limits of detection achieved for all of the analytes were between 17 and 95 ng mL(-1), and the recoveries ranged from 89% to 103%. Furthermore, the enrichment factors ranged from 49 to 57. The proposed method was successfully applied to the analysis of NSAIDs in tap and river water samples.

  8. Determination of atenolol in human plasma using ionic-liquid-based ultrasound-assisted in situ solvent formation microextraction followed by high-performance liquid chromatography.

    PubMed

    Zeeb, Mohsen; Farahani, Hadi; Papan, Mohammad Kazem

    2016-06-01

    An efficient analytical method called ionic-liquid-based ultrasound-assisted in situ solvent formation microextraction followed by high-performance liquid chromatography was developed for the determination of atenolol in human plasma. A hydrophobic ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) was formed by the addition of a hydrophilic ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate) to a sample solution containing an ion-pairing agent during microextraction. The analyte was extracted into the ionic liquid phase while the microextraction solvent was dispersed throughout the sample by utilizing ultrasound. The sample was then centrifuged, and the extracting phase retracted into the microsyringe and injected to liquid chromatography. After optimization, the calibration curve showed linearity in the range of 2-750 ng/mL with the regression coefficient corresponding to 0.998. The limits of detection (S/N = 3) and quantification (S/N = 10) were 0.5 and 2 ng/mL, respectively. A reasonable relative recovery range of 90-96.7% and satisfactory intra-assay (4.8-5.1%, n = 6) and interassay (5.0-5.6%, n = 9) precision along with a substantial sample clean-up demonstrated good performance of the procedure. It was applied for the determination of atenolol in human plasma after oral administration and some pharmacokinetic data were obtained.

  9. Microwave-assisted rapid conversion of carbohydrates into 5-hydroxymethylfurfural by ScCl3 in ionic liquids.

    PubMed

    Zhou, Xuanmu; Zhang, Zehui; Liu, Bing; Xu, Zheng; Deng, Kejian

    2013-06-28

    In this study, synthesis of HMF from carbohydrates was carried out in ionic liquids 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) catalyzed by ScCl3 under microwave irradiation. Under the optimal reaction conditions, HMF was obtained in a high yield of 73.4% in 2 mins with the microwave power at 400 W. Compared with the conventional oil-bath heating manner, the use of microwave irradiation not only reduced reaction times from hours to minutes, but also improved HMF yield. This catalytic system could be reused several times without losing its catalytic activity. This efficient catalytic system will generate a promising application strategy for biomass transformation.

  10. Aggregation and micelle formation of ionic liquids in aqueous solution

    NASA Astrophysics Data System (ADS)

    Miskolczy, Zsombor; Sebők-Nagy, Krisztina; Biczók, László; Göktürk, Sinem

    2004-12-01

    Association of ionic liquids possessing n-octyl moiety either in the cation or in the anion has been studied in aqueous solution with conductivity and turbidity measurements as well as using 2-hydroxy-substituted Nile Red solvatochromic probe. 1-Butyl-3-methylimidazolium octyl sulfate was found to act as a surfactant above 0.031 M critical micelle concentration. In contrast, 1-methyl-3-octylimidazolium chloride produced inhomogeneous solution of larger aggregates, which were dissolved on the addition of more than 2:1 molar excess of sodium dodecyl sulfate (SDS) due to mixed micelle formation. Even small amount (<10 mM) of ionic liquids could markedly reduce the polarity of the Stern layer of SDS micelle.

  11. Hydrolysis of insoluble cellulose to glucose catalyzed by cellulase-containing liposomes in an aqueous solution of 1-butyl-3-methylimidazolium chloride.

    PubMed

    Yoshimoto, Makoto; Tanimura, Kazuhiko; Tokunaga, Kazuki; Kamimura, Akio

    2013-01-01

    The liposome containing cellulase from Trichoderma viride was prepared under the condition that an appreciable amount of cellulase was incorporated in lipid membranes. The liposomal cellulase and free enzyme were examined in their hydrolytic activities to insoluble cellulose powder CC31 in the acetate buffer solution (pH 4.8) of 15 w/w% [Bmim][Cl] (1-butyl-3-methylimidazolium chloride). The mean diameter and size distribution of cellulase-containing liposome were practically unchanged under the above condition. The free cellulase was deactivated more rapidly than the liposomal cellulase in catalyzing the hydrolysis of 2.0 g/l CC31 at 45°C in the presence of [Bmim][Cl] for 48 h. The activities of liposomal and free cellulase to cellobiose as soluble substrate were less susceptible to [Bmim][Cl] than their cellulolytic activities to CC31, meaning that β-glucosidase is relatively stable among the three enzyme components of cellulase. The rate of glucose production could be appreciably improved by the pretreatment of CC31 with [Bmim][Cl] alone at 120°C for 30 min followed by the liposomal cellulase-catalyzed hydrolysis of the substrate at 45°C at the [Bmim][Cl] concentration of 15 w/w%.

  12. Electrochemical behavior of o-sec-butylphenol at glassy carbon electrode modified with multiwalled carbon nanotubes and 1-butyl-3-methylimidazolium hexafluorophosphate.

    PubMed

    Zheng, Shaohua; Huang, Ying; Chen, Guonan

    2012-09-21

    A sensitive electrochemical sensor based on immobilized multiwalled carbon nanotubes (MWCNTs) and 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM·PF(6)) on a glassy carbon electrode (GCE) for o-sec-butylphenol (osBP) was proposed. The electro-oxidation behavior was studied, the experimental conditions were optimized and kinetic parameters were calculated. The results indicated that this electrochemical sensor has the advantages of fast electron-transfer rate, minimal fouling of electrodes, high sensitivity and stability for o-sec-butylphenol. Upon comparison with a glassy carbon electrode, this senor would effectively minimize the over-potential and increase the electrochemical response to o-sec-butylphenol. Under the optimum conditions, the peak current was linear to the osBP concentration range from 1 × 10(-7) to 2.5 × 10(-5) M with the detection limit of 8.65 × 10(-9) M (S/N = 3). The proposed method was applied to the determination of spiked water samples with satisfactory results.

  13. Mechanical exfoliation of graphite in 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6) providing graphene nanoplatelets that exhibit enhanced electrocatalysis

    NASA Astrophysics Data System (ADS)

    Hayes, William Ignatius; Lubarsky, Gennady; Li, Meixian; Papakonstantinou, Pagona

    2014-12-01

    A novel production method for graphene nanoplatelets (GPs) with enhanced electrocatalytic behaviour is presented. GPs show improvement in their oxygen reduction reaction (ORR) catalysis after prolonging the grinding of graphite in 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6). Nitrogen doping of the GPs has inferred a further increase in ORR. The ORR onset potential, cathodic current magnitude and electron transfer efficiency have all improved as a direct consequence of increasing the graphite grinding duration from 30 min to 4 h. Atomic force microscopy has confirmed a decrease in the GP diameter and height as the grinding increases. Raman spectroscopy indicates a higher level of defects present after prolonging the graphite grinding in BMIM-PF6, most likely a result of the increased edge plane exposure. This increased edge plane appears to promote a higher level of nitrogen incorporation as the graphite grinding duration increases, as confirmed by X-ray photoelectron spectroscopy analysis. The stability of the cathodic current assessed by chronoamperometry analysis is higher for the GP and nitrogen doped graphene nanoplatelet (N-GP) samples than the platinum on carbon black (Pt/C). This study presents a novel process for the production of nitrogen doped graphene nanoplatelets, constituting a strategy for the up-scaled production of electrocatalysts.

  14. Ionic liquid tunes microemulsion curvature.

    PubMed

    Liu, Liping; Bauduin, Pierre; Zemb, Thomas; Eastoe, Julian; Hao, Jingcheng

    2009-02-17

    Middle-phase microemulsions formed from cationic dioctadecyldimethylammonium chloride (DODMAC), anionic sodium dodecylsulfate (SDS), n-butanol, and n-heptane were studied. An ionic liquid (IL), 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]), was employed as the electrolyte in the aqueous media instead of inorganic salts usually used in microemulsion formulation. Studies have been carried out as a function of the concentrations of [bmim][BF4], n-butanol, total surfactant (cDODMAC+SDS), and temperature on the phase behavior and the ultralow interfacial tensions in which the anionic component is present in excess in the catanionic film. Ultralow interfacial tension measurements confirmed the formation of middle-phase microemulsions and the necessary conditions for stabilizing middle-phase microemulsions. Electrical conductivity, small-angle X-ray scattering (SAXS), and small-angle neutron scattering (SANS) experiments were also performed, indicating that the typical heptane domain size has an average radius of 360 A and the ionic liquid induces softening of the charged catanionic film. Most interestingly, the IL concentration (cIL) is shown to act as an effective interfacial curvature-control parameter, representing a new approach to tuning the formulation of microemulsions and emulsions. The results expand the potential uses of ILs but also point to the design of new ILs that may achieve superefficient control over interfacial and self-assembly systems.

  15. Heats of vaporization of room temperature ionic liquids by tunable vacuum ultraviolet photoionization

    SciTech Connect

    Chambreau, Steven D.; Vaghjiani, Ghanshyam L.; To, Albert; Koh, Christine; Strasser, Daniel; Kostko, Oleg; Leone, Stephen R.

    2009-11-25

    The heats of vaporization of the room temperature ionic liquids (RTILs) N-butyl-N-methylpyrrolidinium bistrifluorosulfonylimide, N-butyl-N-methylpyrrolidinium dicyanamide, and 1-butyl-3-methylimidazolium dicyanamide are determined using a heated effusive vapor source in conjunction with single photon ionization by a tunable vacuum ultraviolet synchrotron source. The relative gas phase ionic liquid vapor densities in the effusive beam are monitored by clearly distinguished dissociative photoionization processes via a time-of-flight mass spectrometer at a tunable vacuum ultraviolet beamline 9.0.2.3 (Chemical Dynamics Beamline) at the Advanced Light Source synchrotron facility. Resulting in relatively few assumptions, through the analysis of both parent cations and fragment cations, the heat of vaporization of N-butyl-N-methylpyrrolidinium bistrifluorosulfonylimide is determined to be Delta Hvap(298.15 K) = 195+-19 kJ mol-1. The observed heats of vaporization of 1-butyl-3-methylimidazolium dicyanamide (Delta Hvap(298.15 K) = 174+-12 kJ mol-1) and N-butyl-N-methylpyrrolidinium dicyanamide (Delta Hvap(298.15 K) = 171+-12 kJ mol-1) are consistent with reported experimental values using electron impact ionization. The tunable vacuum ultraviolet source has enabled accurate measurement of photoion appearance energies. These appearance energies are in good agreement with MP2 calculations for dissociative photoionization of the ion pair. These experimental heats of vaporization, photoion appearance energies, and ab initio calculations corroborate vaporization of these RTILs as intact cation-anion ion pairs.

  16. Determining diffusion coefficients of ionic liquids by means of field cycling nuclear magnetic resonance relaxometry.

    PubMed

    Kruk, D; Meier, R; Rachocki, A; Korpała, A; Singh, R K; Rössler, E A

    2014-06-28

    Field Cycling Nuclear Magnetic Resonance (FC NMR) relaxation studies are reported for three ionic liquids: 1-ethyl-3- methylimidazolium thiocyanate (EMIM-SCN, 220-258 K), 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM-BF4, 243-318 K), and 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6, 258-323 K). The dispersion of (1)H spin-lattice relaxation rate R1(ω) is measured in the frequency range of 10 kHz-20 MHz, and the studies are complemented by (19)F spin-lattice relaxation measurements on BMIM-PF6 in the corresponding frequency range. From the (1)H relaxation results self-diffusion coefficients for the cation in EMIM-SCN, BMIM-BF4, and BMIM-PF6 are determined. This is done by performing an analysis considering all relevant intra- and intermolecular relaxation contributions to the (1)H spin-lattice relaxation as well as by benefiting from the universal low-frequency dispersion law characteristic of Fickian diffusion which yields, at low frequencies, a linear dependence of R1 on square root of frequency. From the (19)F relaxation both anion and cation diffusion coefficients are determined for BMIM-PF6. The diffusion coefficients obtained from FC NMR relaxometry are in good agreement with results reported from pulsed- field-gradient NMR. This shows that NMR relaxometry can be considered as an alternative route of determining diffusion coefficients of both cations and anions in ionic liquids.

  17. Plasticizing effect of ionic liquid on cellulose acetate obtained by melt processing.

    PubMed

    Bendaoud, Amine; Chalamet, Yvan

    2014-08-08

    Cellulose acetate (CA) plasticized by 1-butyl-3-methylimidazolium chloride (BMIMCl) and with diethylphtalate (DEP) was obtained by melt processing at 150°C. The effect and the interaction of ionic liquid with the cellulose acetate and their influence on structural, thermo-mechanical, rheological and tensile properties of CA materials were investigated. Ionic liquid (BMIMCl) has shown a good plasticization and more efficient destruction of the crystalline structure of cellulose acetate than the DEP plasticized CA. BMIMCl interacts intensively with CA molecules due to the pronounced van der Waals interactions, hydrogen bonding and electrostatic nature of ionic liquid. The tensile test and the low Young's modulus for plasticized CA suggest a strong reduction of the interaction between the CA chains due to the presence of the ionic liquid.

  18. Rotational Diffusion of Charged and Nondipolar Solutes in Ionic Liquid-Organic Solvent Mixtures: Evidence for Stronger Specific Solute-Solvent Interactions in Presence of Organic Solvent.

    PubMed

    Prabhu, Sugosh R; Dutt, G B

    2015-08-20

    Rotational diffusion of a charged solute, rhodamine 110 (R110), and a nondipolar solute, 2,5-dimethyl-1,4-dioxo-3,6-diphenylpyrrolo[3,4-c]pyrrole (DMDPP), has been investigated in ionic liquids, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMIM][Tf2N]) and 1-butyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate ([BMIM][FAP]), with 0.8 mole fraction of dibenzyl ether (DBE). This study has been undertaken to find out how specific interactions between the solute and the ionic liquid are affected upon dilution with a nondipolar solvent. It has been observed that at a given viscosity (η) and temperature (T), the reorientation times of R110 increase by 40-60% in the ionic liquid-organic solvent mixtures compared to ones in the corresponding neat ionic liquids. In the case of DMDPP, the influence of DBE is less pronounced, and its reorientation times increase by 25-50% at a given η/T. The addition of DBE weakens the numerous interactions prevailing between the cations and the anions of the ionic liquids, which results in stronger specific interactions between the solutes and the constituent ions, consequently leading to slower rotation of the solutes.

  19. Preparation and characterisation of high-density ionic liquids incorporating halobismuthate anions.

    PubMed

    Cousens, Nico E A; Taylor Kearney, Leah J; Clough, Matthew T; Lovelock, Kevin R J; Palgrave, Robert G; Perkin, Susan

    2014-07-28

    A range of ionic liquids containing dialkylimidazolium cations and halobismuthate anions ([BiBr(x)Cl(y)I(z)](-) and [Bi2Br(x)Cl(y)I(z)](-)) were synthesised by combining dialkylimidazolium halide ionic liquids with bismuth(III) halide salts. The majority were room temperature liquids, all with very high densities. The neat ionic liquids and their mixtures with 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide were characterised using Densitometry, Viscometry, NMR Spectroscopy, Electrospray Ionisation Mass Spectrometry (ESI), Liquid Secondary Ion Mass Spectrometry (LSIMS), Matrix-assisted Laser Desorption/Ionization Mass Spectrometry (MALDI), X-Ray Photoelectron Spectroscopy (XPS) and Thermogravimetric Analysis (TGA), to establish their speciation and suitability for high-temperature applications.

  20. Interfacial interactions in aprotic ionic liquid based protonic membrane and its correlation with high temperature conductivity and thermal properties.

    PubMed

    Mistry, Mayur K; Subianto, Surya; Choudhury, Namita Roy; Dutta, Naba K

    2009-08-18

    Novel supported liquid membranes (SLMs) have been developed by impregnating Nafion and Hyflon membranes with ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMI-BTSI). These supported liquid membranes were characterized in terms of their ionic liquid uptake behavior, leaching of ionic liquid by water, thermal stability, mechanical properties, glass transition temperature, ion exchange capacity, and proton conductivity. In general, modified membranes are more flexible than unmodified samples due to the plasticization effects of the ionic liquid. However, these supported liquid membranes exhibit a significant increase in their operational stability and proton conductivity over unmodified membranes. We also demonstrate that proton conductivity of these supported liquid membranes allows conduction of protons in anhydrous conditions with conductivity increasing with temperature. Conductivity of up to 3.58 mS cm(-1) has been achieved at 160 degrees C in dry conditions, making these materials promising for various electrochemical applications.

  1. A study of the time-resolved fluorescence spectrum and red edge effect of ANF in a room-temperature ionic liquid.

    PubMed

    Hu, Zhonghan; Margulis, Claudio J

    2006-06-15

    In a recent article, we have analyzed using molecular dynamics simulations the steady-state red edge effect (REE) observed by Samanta and co-workers when the fluorescent probe 2-amino-7-nitrofluorene (ANF) is photoexcited at different wavelengths in 1-butyl-3-methylimidazolium ([BMIM+]) hexafluorophosphate ([PF6-]). In this letter, we predict the time- and wavelength-dependent emission spectra of ANF in the same ionic solvent. From the analysis of our simulated data, we are able to derive an approximate time scale for reorganization of the solvent around the solute probe. The effect that slow varying local liquid environments have on the overall time-dependent signal is also discussed.

  2. Atomic Resolution Insights into the Structural Aggregations and Optical Properties of Neat Imidazolium-Based Ionic Liquids.

    PubMed

    Du, Likai; Geng, Cuihuan; Zhang, Dongju; Lan, Zhenggang; Liu, Chengbu

    2016-07-14

    A fundamental understanding of the structural heterogeneity and optical properties of ionic liquids is crucial for their potential applications in catalysis, optical measurement, and solar cells. Herein, a synergistic approach combining molecular dynamics simulations, excited-state calculations, and statistical analysis was used to explore the explicit correlation between the structural and optical properties of one imidazolium amino acid-based ionic liquid, 1-butyl-3-methylimidazolium glycine. The estimated absorption spectrum successfully rationalizes the unusual and non-negligible absorption band beyond 300 nm for the neat imidazolium-based ionic liquid. The absorption behavior of imidazolium-based ionic liquids is shown to be sensitive to the details of their locally heterogeneous environments. We quantitatively highlight the imidazolium moiety and its various molecular aggregations, rather than the monomeric imidazolium moiety, that are responsible for the absorption characteristics. These results would improve our understanding of the preliminary interplay between structural heterogeneity and optical properties for neat imidazolium-based ionic liquids.

  3. Solute-solvent interactions in imidazolium camphorsulfonate ionic liquids.

    PubMed

    Nobuoka, Kaoru; Kitaoka, Satoshi; Iio, Masashi; Harran, Thomas; Ishikawa, Yuichi

    2007-11-28

    We directly observe the interaction between 1-butyl-3-methylimidazolium (bmim) or 1-butyl-2,3-dimethylimidazolium (bm(2)im) and the solute, ethyl acrylate (EA), which is the popular dienophile in the Diels-Alder reaction and an H-bonding acceptor, by using specially designed electrospray mass spectrometry. In imidazolium ionic liquids, cation-anion interactions are controlled by selecting the appropriate anion, and the naked C(2)-H of imidazolium, which loosely interacts with its counterion, can readily interact with an H-bonding acceptable solute. The ion-counterion (solvent-solvent) interaction affects the ion-solute (solvent-solute) interaction. This relation is one of the key criteria for selecting the cation-anion combination in tailoring ILs.

  4. Synthesis of cellulose dehydroabietate in ionic liquid [bmim]Br.

    PubMed

    Xu, Xuetang; Duan, Wengui; Huang, Mei; Li, Guanghua

    2011-09-27

    A new type of cellulose derivative, cellulose dehydroabietate (CDA), was synthesized by the O-acylation reaction of cellulose with dehydroabietic acid chloride (DHAC) using ionic liquid 1-butyl-3-methylimidazolium bromide ([bmim]Br) as a solvent and 4-dimethyl-aminopyridine (DMAP) as a catalyst. The resulting CDA was characterized by means of FT-IR, X-ray diffraction (XRD), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), and elemental analysis. Also, some properties of CDA were determined. These results showed that CDA has better solubility, water-repellency, and resistance to acids and bases than raw cellulose, and these properties increase with the DS of CDA. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Fabrication of ionic liquid ultrathin film by sequential deposition

    NASA Astrophysics Data System (ADS)

    Morino, Yusuke; Kanai, Yuta; Imanishi, Akihito; Yokota, Yasuyuki; Fukui, Ken-ichi

    2014-01-01

    A simple, mild, reproducible, and controllable nanodeposition method for ionic liquids (ILs) by ejection of IL solution through a high-speed electromagnetic valve (pulse valve) to a substrate under vacuum is proposed (pulse-valve method). Sequential deposition of an IL [1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (BMIM-TFSI)] on Au(111) substrates from its methanol solution was examined by adopting the pulse-valve method and the deposited IL films were analyzed by X-ray photoelectron spectroscopy (XPS) and tapping-mode atomic force microscopy (AFM). The amount of IL deposited per a pulse was successfully reduced to less than an equivalent thickness of 0.2 nm. The deposited IL was homogeneously distributed over a substrate area of 1 × 1 cm2 substrate area and the deposited amount was reproducible for independent depositions.

  6. Mixed ionic liquid as electrolyte for lithium batteries

    NASA Astrophysics Data System (ADS)

    Diaw, M.; Chagnes, A.; Carré, B.; Willmann, P.; Lemordant, D.

    Ionic liquids like 1-butyl-3-methylimidazolium tetrafluoroborate (IMIBF 4) or hexafluorophosphate (IMIPF 6) and 1-butyl-4-methylpyridinium tetrafluoroborate (PyBF 4) were mixed with organic solvents such as butyrolactone (BL) and acetonitrile (ACN). A lithium salt (LiBF 4 or LiPF 6) was added to these mixtures for possible application in the field of energy storage (batteries or supercapacitors). Viscosities, conductivities and electrochemical windows at a Pt electrode of these electrolytes were investigated. All studied electrolytes are stable toward oxidation and exhibit a vitreous phase transition, which has been determined by application of the VTF theory to conductivity measurements. Mixtures containing the BF 4- anion exhibit the lowest viscosity and the highest conductivity. Two mixtures have been optimized in terms of conductivity: BL/IMIBF 4 (60/40, v/v) and ACN/IMIBF 4 (70/30, v/v).

  7. Ion gels by self-assembly of a triblock copolymer in an ionic liquid.

    PubMed

    He, Yiyong; Boswell, Paul G; Bühlmann, Philippe; Lodge, Timothy P

    2007-05-10

    We report a new way of developing ion gels through the self-assembly of a triblock copolymer in a room-temperature ionic liquid. Transparent ion gels were achieved by gelation of a poly(styrene-block-ethylene oxide-block-styrene) (SOS) triblock copolymer in 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) with as low as 5 wt % SOS triblock copolymer. The gelation behavior, ionic conductivity, rheological properties, and microstructure of the ion gels were investigated. The ionic conductivity of the ion gels is only modestly affected by the triblock copolymer network. Its temperature dependence nearly tracks that of the bulk ionic liquid viscosity. The ion gels are thermally stable up to at least 100 degrees C and possess significant mechanical strength. The results presented here suggest that triblock copolymer gelation is a promising way to develop highly conductive ion gels and provides many advantages in terms of variety and processing.

  8. Investigation of binary and ternary systems of ionic liquids with water and/or supercritical CO2 by in situ attenuated total reflection infrared spectroscopy.

    PubMed

    Andanson, Jean-Michel; Jutz, Fabian; Baiker, Alfons

    2010-02-18

    Two commonly used ionic liquids (ILs), 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF(4)]) and 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF(6)]), as well as binary and ternary mixtures of them with water and/or supercritical CO(2) (scCO(2)) were investigated by means of infrared spectroscopy at high pressure. The experiments were performed using attenuated total reflection (ATR) infrared spectroscopy on dry and wet ILs at 40 degrees C and pressures up to 150 bar of scCO(2). The studies indicate that the content of water does not change significantly the solubility of CO(2) in the ionic liquids tested. Furthermore, the presence of water does not change significantly the interaction between the IL anion and CO(2), which explains why the presence of water in IL does not modify the solubility of CO(2) in the system, even in the case of an initial molar ratio of approximately 50/50 of water in [bmim][BF(4)]. We show that despite the limited solubility of water in supercritical CO(2) an ionic liquid can be efficiently dried using scCO(2) extraction even in the case of a hydrophilic ionic liquid (e.g., [bmim][BF(4)]). During the scCO(2) extraction, the concentration of water was followed in situ using attenuated total reflection (ATR) infrared spectroscopy. After extraction, no residual water could be detected by this technique, which corresponds approximately to a water concentration of below 320 ppm.

  9. Molecular dynamics study of ionic liquids complexation within β-cyclodextrins.

    PubMed

    Semino, Rocío; Rodríguez, Javier

    2015-04-09

    We have studied 1:1 inclusion complexes of two imidazole-based ionic liquids within β-cyclodextrin: 1-dodecyl-3-methylimidazolium and 1-butyl-3-methylimidazolium. By means of an adaptive biasing force scheme, we obtained the free energy profile along two different pathways, differing in the orientations of the head-to-tail vector with respect to the primary-secondary rim axis. Regarding 1-dodecyl-3-methylimidazolium, we found one minimum energy structure for each pathway, in which the hydrophobic tail remains embedded within the cyclodextrin, while the headgroup lies ∼11-12 Å from one of the rims; the structure where the polar head lies near the primary rim is the most stable. The analysis of the free energy of encapsulation of 1-butyl-3-methylimidazolium shows two minima for each insertion pathway, each of them associated with configurations where the imidazolium head lies close to one of the polar rims. As such, the most stable structure corresponds to one where the hydrophobic tail lies embedded within the cyclodextrin, while its head is localized near the secondary rim. The results are interpreted in terms of a simple model which captures the essential features that control the encapsulation process. A comparison with available experimental data is presented.

  10. Surface tension of room temperature ionic liquids measured by dynamic light scattering.

    PubMed

    Osada, R; Hoshino, T; Okada, K; Ohmasa, Y; Yao, M

    2009-05-14

    Using dynamic light scattering techniques, we obtained the surface tension sigma, surface excess entropy S(sigma), surface excess enthalpy H(sigma), and viscosity eta for the following seven room temperature ionic liquids in a wide temperature range from 30 to around 140 degrees C: 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, N-methyl-N-propylpiperidinium bis(trifluoromethanesulfonyl)imide, N,N,N-trimethyl-N-propylammonium bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-hexyl-3-methylimidazolium hexafluorophosphate, and 1-octyl-3-methyl imidazolium hexafluorophosphate. We have found that sigma increases systematically with decreasing the anion size and the alkyl side chain length. On the other hand, S(sigma) and eta increase with decreasing the anion size but decrease with decreasing the alkyl chain length. H(sigma) seems to decrease with increasing the anion size, but it has no clear dependence on the alkyl chain length. We discuss the bulk and surface properties, referring to the Coulomb interactions and van der Waals interactions.

  11. Surface tension of room temperature ionic liquids measured by dynamic light scattering

    NASA Astrophysics Data System (ADS)

    Osada, R.; Hoshino, T.; Okada, K.; Ohmasa, Y.; Yao, M.

    2009-05-01

    Using dynamic light scattering techniques, we obtained the surface tension σ, surface excess entropy S(σ), surface excess enthalpy H(σ), and viscosity η for the following seven room temperature ionic liquids in a wide temperature range from 30 to around 140 °C: 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, N-methyl-N-propylpiperidinium bis(trifluoromethanesulfonyl)imide, N,N,N-trimethyl-N-propylammonium bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-hexyl-3-methylimidazolium hexafluorophosphate, and 1-octyl-3-methyl imidazolium hexafluorophosphate. We have found that σ increases systematically with decreasing the anion size and the alkyl side chain length. On the other hand, S(σ) and η increase with decreasing the anion size but decrease with decreasing the alkyl chain length. H(σ) seems to decrease with increasing the anion size, but it has no clear dependence on the alkyl chain length. We discuss the bulk and surface properties, referring to the Coulomb interactions and van der Waals interactions.

  12. Alkylation of Methyl Linoleate with Propene in Ionic Liquids in the Presence of Metal Salts.

    PubMed

    Pomelli, Christian Silvio; Ghilardi, Tiziana; Chiappe, Cinzia; de Angelis, Alberto Renato; Calemma, Vincenzo

    2015-12-07

    Vegetable oils and fatty acid esters are suitable precursor molecules for the production of a variety of bio-based products and materials, such as paints and coatings, plastics, soaps, lubricants, cosmetics, pharmaceuticals, printing inks, surfactants, and biofuels. Here, we report the possibility of using Lewis acidic ionic liquids (ILs) to obtain polyunsaturated ester dimerization-oligomerization and/or, in the presence of another terminal alkene (propene), co-polymerization. In particular, we have tested the Lewis acidic mixtures arising from the addition of a proper amount of GaCl₃ (Χ > 0.5) to two chloride-based (1-butyl-3-methylimidazolium chloride, [bmim]Cl, and 1-butylisoquinolium chloride, [BuIsoq]Cl) or by dissolution of a smaller amount of Al(Tf₂N)₃ (Χ = 0.1) in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [bmim][Tf₂N]. On the basis of product distribution studies, [bmim][Tf₂N]/Al(Tf₂N)₃ appears the most suitable medium in which methyl linoleate alkylation with propene can compete with methyl linoleate or propene oligomerization.

  13. Heteroatom-Containing Porous Carbons Derived from Ionic Liquid-Doped Alkali Organic Salts for Supercapacitors.

    PubMed

    Zhu, Jingyue; Xu, Dan; Qian, Wenjing; Zhang, Jinyu; Yan, Feng

    2016-04-13

    A simple strategy for the synthesis of heteroatom-doped porous carbon materials (CMs) via using ionic liquid (IL)-doped alkali organic salts as small molecular precursors is developed. Doping of alkali organic salts (such as sodium glutamate, sodium tartrate, and sodium citrate) with heteroatoms containing ILs (including 1-butyl-3-methylimidazolium chlorine and 3-butyl-4-methythiazolebromination) not only incorporates the heteroatoms into the carbon frameworks but also highly improves the carbonization yield, as compared with that of either alkali organic salts or ILs as precursors. The porous structure of CMs can be tuned by adjusting the feed ratio of ILs. The porous CMs derived from 1-butyl-3-methylimidazolium chlorine-doped sodium glutamate exhibit high charge storage capacity with a specific capacitance of 287 F g(-1) and good stability over 5000 cycles in 6 m KOH at a current density of 1 A g(-1) for supercapacitors. This strategy opens a simple and efficient method for the synthesis of heteroatom-doped porous CMs.

  14. Separation of lignin from corn stover hydrolysate with quantitative recovery of ionic liquid

    DOE PAGES

    Underkofler, Kaylee A.; Teixeira, Rodrigo E.; Pietsch, Stephen A.; ...

    2015-02-20

    Abundant lignocellulosic biomass could become a source of sugars and lignin, potential feedstocks for the now emergent biorenewable economy. The production and conversion of sugars from biomass have been well-studied, but far less is known about the production of lignin that is amenable to valorization. In this paper, we report the isolation of lignin generated from the hydrolysis of biomass dissolved in the ionic liquid 1-butyl-3-methylimidazolium chloride. We show that lignin can be isolated from the hydrolysate slurry by simple filtration or centrifugation, and that the ionic liquid can be recovered quantitatively by a straightforward wash with water. Finally, themore » isolated lignin is not only free from ionic liquid but also lacks cellulosic residues and is substantially depolymerized, making it a promising feedstock for valorization by conversion into fuels and chemicals.« less

  15. Separation of lignin from corn stover hydrolysate with quantitative recovery of ionic liquid

    SciTech Connect

    Underkofler, Kaylee A.; Teixeira, Rodrigo E.; Pietsch, Stephen A.; Knapp, Kurtis G.; Raines, Ronald T.

    2015-02-20

    Abundant lignocellulosic biomass could become a source of sugars and lignin, potential feedstocks for the now emergent biorenewable economy. The production and conversion of sugars from biomass have been well-studied, but far less is known about the production of lignin that is amenable to valorization. In this paper, we report the isolation of lignin generated from the hydrolysis of biomass dissolved in the ionic liquid 1-butyl-3-methylimidazolium chloride. We show that lignin can be isolated from the hydrolysate slurry by simple filtration or centrifugation, and that the ionic liquid can be recovered quantitatively by a straightforward wash with water. Finally, the isolated lignin is not only free from ionic liquid but also lacks cellulosic residues and is substantially depolymerized, making it a promising feedstock for valorization by conversion into fuels and chemicals.

  16. Dissolution and regeneration of Bombyx mori silk fibroin using ionic liquids.

    PubMed

    Phillips, David M; Drummy, Lawrence F; Conrady, Deborah G; Fox, Douglas M; Naik, Rajesh R; Stone, Morley O; Trulove, Paul C; De Long, Hugh C; Mantz, Robert A

    2004-11-10

    In this work, the suitability of imidazolium-based ionic liquid solvents is investigated for the dissolution and regeneration of silkworm (Bombyx mori) silk. Within an ionic liquid the anion plays a larger role in dictating the ultimate solubility of the silk. The dissolution of the silk in the ionic liquid is confirmed using wide-angle X-ray scattering. The dissolved silk is also processed into 100 mum-thick, two-dimensional films, and the structure of these films is examined. The rinse solvent, acetonitrile or methanol, has a profound impact on both the topography of the films and the secondary structure of the silk protein. The image depicts a silkworm cocoon dissolved in 1-butyl-3-methylimidazolium chloride and then regenerated as a film with birefringence.

  17. Spectroscopic analysis of 1-butyl-2,3-dimethylimidazolium ionic liquids: Cation-anion interactions

    NASA Astrophysics Data System (ADS)

    Men, Shuang; Jiang, Jing; Licence, Peter

    2017-04-01

    In this study, four 1-butyl-2,3-dimethylimidazolium ionic liquids are analysed by X-ray photoelectron spectroscopy, together with three 1-butyl-3-methylimidazolium ionic liquids. A reliable fitting model for the carbon 1s region of 1-butyl-2,3-dimethylimidazolium ionic liquids is modified according to established models. The effect of the anion on the electronic environment of the cation is explored based upon the comparison between measured binding energies of nitrogen 1s and the hydrogen bond acceptor ability. The effect of the cation on the cation-anion interaction is also demonstrated by carefully comparing the hydrogen bond donating ability of different cations, with a definite anion.

  18. Reactions of Ions with Ionic Liquid Vapors by Selected-Ion Flow Tube Mass Spectrometry.

    PubMed

    Chambreau, Steven D; Boatz, Jerry A; Vaghjiani, Ghanshyam L; Friedman, Jeffrey F; Eyet, Nicole; Viggiano, A A

    2011-04-21

    Room-temperature ionic liquids exert vanishingly small vapor pressures under ambient conditions. Under reduced pressure, certain ionic liquids have demonstrated volatility, and they are thought to vaporize as intact cation-anion ion pairs. However, ion pair vapors are difficult to detect because their concentration is extremely low under these conditions. In this Letter, we report the products of reacting ions such as NO(+), NH4(+), NO3(-), and O2(-) with vaporized aprotic ionic liquids in their intact ion pair form. Ion pair fragmentation to the cation or anion as well as ion exchange and ion addition processes are observed by selected-ion flow tube mass spectrometry. Free energies of the reactions involving 1-ethyl-3-methylimidazolium bis-trifluoromethylsulfonylimide determined by ab initio quantum mechanical calculations indicate that ion exchange or ion addition are energetically more favorable than charge-transfer processes, whereas charge-transfer processes can be important in reactions involving 1-butyl-3-methylimidazolium dicyanamide.

  19. Separation of Lignin from Corn Stover Hydrolysate with Quantitative Recovery of Ionic Liquid.

    PubMed

    Underkofler, Kaylee A; Teixeira, Rodrigo E; Pietsch, Stephen A; Knapp, Kurtis G; Raines, Ronald T

    2015-04-06

    Abundant lignocellulosic biomass could become a source of sugars and lignin, potential feedstocks for the now emergent bio-renewable economy. The production and conversion of sugars from biomass have been well-studied, but far less is known about the production of lignin that is amenable to valorization. Here we report the isolation of lignin generated from the hydrolysis of biomass dissolved in the ionic liquid 1-butyl-3-methylimidazolium chloride. We show that lignin can be isolated from the hydrolysate slurry by simple filtration or centrifugation, and that the ionic liquid can be recovered quantitatively by a straightforward wash with water. The isolated lignin is not only free from ionic liquid, but also lacks cellulosic residues and is substantially depolymerized, making it a promising feedstock for valorization by conversion into fuels and chemicals.

  20. Separation of Lignin from Corn Stover Hydrolysate with Quantitative Recovery of Ionic Liquid

    PubMed Central

    Underkofler, Kaylee A.; Teixeira, Rodrigo E.; Pietsch, Stephen A.; Knapp, Kurtis G.; Raines, Ronald T.

    2015-01-01

    Abundant lignocellulosic biomass could become a source of sugars and lignin, potential feedstocks for the now emergent bio-renewable economy. The production and conversion of sugars from biomass have been well-studied, but far less is known about the production of lignin that is amenable to valorization. Here we report the isolation of lignin generated from the hydrolysis of biomass dissolved in the ionic liquid 1-butyl-3-methylimidazolium chloride. We show that lignin can be isolated from the hydrolysate slurry by simple filtration or centrifugation, and that the ionic liquid can be recovered quantitatively by a straightforward wash with water. The isolated lignin is not only free from ionic liquid, but also lacks cellulosic residues and is substantially depolymerized, making it a promising feedstock for valorization by conversion into fuels and chemicals. PMID:25866701

  1. Application of Ionic Liquids in the Microwave-Assisted Extraction of Proanthocyanidins from Larix gmelini Bark

    PubMed Central

    Yang, Lei; Sun, Xiaowei; Yang, Fengjian; Zhao, Chunjian; Zhang, Lin; Zu, Yuangang

    2012-01-01

    Ionic liquid based, microwave-assisted extraction (ILMAE) was successfully applied to the extraction of proanthocyanidins from Larix gmelini bark. In this work, in order to evaluate the performance of ionic liquids in the microwave-assisted extraction process, a series of 1-alkyl-3-methylimidazolium ionic liquids with different cations and anions were evaluated for extraction yield, and 1-butyl-3-methylimidazolium bromide was selected as the optimal solvent. In addition, the ILMAE procedure for the proanthocyanidins was optimized and compared with other conventional extraction techniques. Under the optimized conditions, satisfactory extraction yield of the proanthocyanidins was obtained. Relative to other methods, the proposed approach provided higher extraction yield and lower energy consumption. The Larix gmelini bark samples before and after extraction were analyzed by Thermal gravimetric analysis, Fourier-transform infrared spectroscopy and characterized by scanning electron microscopy. The results showed that the ILMAE method is a simple and efficient technique for sample preparation. PMID:22606036

  2. The use of CE ECL with ionic liquid for the determination of drug alkaloids and applications in human urine.

    PubMed

    Liu, Yan-Ming; Tian, Wei; Jia, Yu-Xiu; Yue, Hai-Yan

    2009-04-01

    A new approach for the determination of methylephedrine hydrochloride (ME), thebaine, codeine phosphate (CP), and acetylcodeine (AC) was established by CE-ECL with ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate). The conditions for the CE separation, ECL detection, and the effect of ionic liquid were systematically investigated. Under the optimal conditions, the four analytes were well separated within 8 min using 1-butyl-3-methylimidazolium tetrafluoroborate as additive in the electrophoretic buffer. The concentration detection limits of ME, thebaine, CP, and AC were 2.1 x 10(-8), 1.4 x 10(-7), 6.3 x 10(-8), and 3.6 x 10(-8) mol/L (S/N=3), respectively. The LOQs (S/N=10) in real human urine samples were 7.6 x 10(-7) mol/L for ME, 3.6 x 10(-6) mol/L for thebaine, 6.5 x 10(-7) mol/L for CP, and 4.6 x 10(-7) mol/L for AC, respectively. The recoveries of four alkaloids at different levels in human urine samples were between 90.0 and 103.5%. The developed method was successfully applied to the determination of four drug alkaloids in human urine samples.

  3. Salting-out effects in aqueous ionic liquid solutions: cloud-point temperature shifts.

    PubMed

    Trindade, Joana R; Visak, Zoran P; Blesic, Marijana; Marrucho, Isabel M; Coutinho, João A P; Lopes, José N Canongia; Rebelo, Luis P N

    2007-05-10

    The effects of the addition of three inorganic salts, namely, NaCl, Na(2)SO(4), and Na(3)PO(4), on the liquid-liquid (L-L) phase diagram of aqueous solutions containing the model ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate, [bmim][BF(4)], were investigated. All three inorganic salts trigger salting-out effects, leading to significant upward shifts of the L-L demixing temperatures of the systems. The magnitude of the shifts depends on both the water-structuring nature of the salt and its concentration; that is, the effects are correlated with the ionic strength of the solution and the Gibbs free energy of hydration of the inorganic salt. The pH effect and the occurrence of salt precipitation in concentrated solutions are also discussed.

  4. Probing intermolecular interactions in water/ionic liquid mixtures by far-infrared spectroscopy.

    PubMed

    Dominguez-Vidal, Ana; Kaun, Nina; Ayora-Cañada, Maria Jose; Lendl, Bernhard

    2007-05-03

    Far-infrared spectra in the range from 600 to 20 cm-1 of two hydrophilic (1-ethyl-3-methylimidazolium tetrafluoroborate and 1-butyl-3-methylimidazolium tetrafluoroborate) and one hydrophobic (1-butyl-3-methylimidazolium hexafluorophosphate) ionic liquids and their mixtures with water at different concentrations are reported. Shifts of the librational water bands depending on the nature of the anion are found to be related to the strength of the interaction between the water molecules and the anions. For both hydrophilic ionic liquids, the librational band is centered around 460 cm-1, whereas for the hydrophobic ionic liquid, it is shifted to 388 cm-1, indicating less hindered rotation of single water molecules. Multivariate curve resolution, paying special attention to the spectral range from 50 to 350 cm-1, was used to investigate the presence of different species with increasing water concentration. For both hydrophilic ionic liquids, a band located at 153 cm-1 was resolved into two different contributions. A small contribution at 202 cm-1 can be attributed to intermolecular interactions between water molecules forming dimers. The major contribution (centered at 148 cm-1) corresponds to water molecules that do not bond to each other via H-bonding. It is therefore assigned to a hindered translation arising from the stretching of the hydrogen bond between BF4- anions and water molecules. Formation of water dimers in the hydrophobic ionic liquid does not occur. Furthermore, the spectral contribution of the stretching of H-bonds between water molecules and PF6- cannot be unambiguously detected, which indicates an extremely weak interaction between water molecules and this anion.

  5. Ionic liquid-linked dual magnetic microextraction of lead(II) from environmental samples prior to its micro-sampling flame atomic absorption spectrometric determination.

    PubMed

    Yilmaz, Erkan; Soylak, Mustafa

    2013-11-15

    A novel and rapid microextraction approach termed as ionic liquid-linked dual magnetic microextraction (IL-DMME), was developed for the atomic absorption spectrometric determination of lead. The developed method based on a combination of dispersive liquid-liquid microextraction (DLLME) and dispersive micro solid-phase extraction (D-μ-SPE). In the first DLLME step, 1-butyl-3-methylimidazolium hexafluorophosphate [C4mim][PF6], was selected to extract the lead-pyrrolidine-dithiocarbamate (Pb-PDC) complex from sample solution by the assistance of vortex agitator. After the first step, fifty milligrams of Fe3O4 magnetic nanoparticles (MNPs) were added to extraction of the ionic liquid and Pb-PDC complex in aqueous solution. The effective factors in proposed IL-DMME procedure, including volume of 1-butyl-3-methylimidazolium hexafluorophosphate, amount of Fe3O4 magnetic nanoparticles, vortex time, amount of ammonium pyrrolidinedithiocarbamate, sample volume and matrix effect were optimized in details. Under the optimal conditions, the method present has low detection limit (0.57 μg L(-1)), high preconcentration factor (160) and good repeatability (<7.5%, n=10). The accuracy of the developed method was evaluated by the analysis of the certified reference materials and addition-recovery tests. The method was successfully applied to the determination of lead in water, plant and hair samples. © 2013 Elsevier B.V. All rights reserved.

  6. Selective quenching of 2-naphtholate fluorescence by imidazolium ionic liquids.

    PubMed

    Kumar, Vinod; Pandey, Siddharth

    2012-10-04

    The effect of addition of water-miscible ionic liquids (ILs), 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF(4)]), 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([bmim][OTf]), and 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate ([bmpyrr][OTf]), on photophysical properties of 2-naphthol in water at various pHs is reported. Electronic absorbance behavior of 2-naphthol dissolved in aqueous mixtures of ILs is observed to be similar to that found in water at different pHs. The excited-state properties, however, are changed dramatically as the IL is added to the milieu. The presence of imidazolium IL results in significant quenching of the fluorescence emission from 2-naphtholate. On the contrary, pyrrolidinium IL does not quench the fluorescence from the anionic species. The quenching of 2-naphtholate fluorescence by aromatic imidazolium cations in aqueous IL mixtures is found to follow simple Stern-Volmer behavior. The aromatic imidazolium cation acts as an electron/charge acceptor during the quenching process where formation of a weakly fluorescent complex between the imidazolium cation and the excited 2-naphtholate anion possibly involving the acidic C2 proton of imidazolium is proposed. Because of the absence of such an acidic proton, the nonaromatic pyrrolidinium cation is not able to form a complex with the excited 2-naphtholate and cannot act as an electron/charge acceptor. Excited-state emission intensity decay data further corroborate this hypothesis as the intensity decay fits well to a single-exponential decay with no change in recovered lifetimes as [bmpyrr][OTf] is added; a double-exponential decay is required to satisfactorily fit the decay data in the presence of [bmim][BF(4)], hinting at the presence of a weakly fluorescent complex. The uniqueness of ILs in affecting excited-state properties of the 2-naphthol system is demonstrated through comparison with NaBF(4), NaCl, and polyethylene glycol with an average molecular weight of

  7. Ionic structures of nanobased FeCl3/[C4mim]Cl ionic liquids.

    PubMed

    Li, Ji-Guang; Hu, Yu-Feng; Sun, Shu-Feng; Ling, Shan; Zhang, Jin-Zhu

    2012-06-07

    We synthesized a series of FeCl(3)/[C(4)mim]Cl (iron(III) chloride with 1-butyl-3-methylimidazolium chloride) ionic liquids. The temperature dependence of the Raman spectra of the FeCl(3)/[C(4)mim]Cl ionic liquids was measured for the first time to analyze their ionic species. In addition, the infrared spectra, thermodynamic properties, and freeze-fracture transmission electron microscopy were combined together with the Raman spectra to reveal the microscopic information of the FeCl(3)/[C(4)mim]Cl ionic liquids. When the mole ratio of FeCl(3)/[C(4)mim]Cl is less than 1, the Raman scattering identifies the presence of [FeCl(4)](-) in the ionic liquid. When FeCl(3) is in excess, [Fe(2)Cl(7)](-) begins to appear. Besides, we found that the relative intensity of the two symmetry vibrations of [Fe(2)Cl(7)](-) is changing as the temperature is varied. The strength of the interionic interactions in FeCl(3)/[C(4)mim]Cl ionic liquids follows the order 1/1.5 > 1.5/1 > 1/1 due to the formation of [FeCl(4)](-) and [Fe(2)Cl(7)](-). The nanostructures in FeCl(3)/[C(4)mim]Cl ionic liquids were observed for the first time by using biological imaging. The sizes of the local domains are found to be tens of nanometers.

  8. Development of sample preparation method for eleutheroside B and E analysis in Acanthopanax senticosus by ionic liquids-ultrasound based extraction and high-performance liquid chromatography detection.

    PubMed

    Yang, Lei; Ge, Hongshuang; Wang, Wenjie; Zu, Yuangang; Yang, Fengjian; Zhao, Chunjian; Zhang, Lin; Zhang, Ying

    2013-12-01

    An ionic liquids-based ultrasonic-assisted extraction (ILUAE) method was successfully developed for extracting eleutheroside B and E from Radix Acanthopanax senticosus. Thirteen 1-alkyl-3-methylimidazolium ionic liquids with different cations and anions were investigated and 1-butyl-3-methylimidazolium bromide ([C4mim]Br) solution was selected as the solvent. The conditions for ILUAE, including the ionic liquid concentration, soaking time, ultrasonic power, ultrasonic time, solid-liquid ratio and number of extraction cycles, were optimized. With the proposed method, the energy consumption time was reduced to 30 min, whereas conventional method requires about 4h. The proposed method had good recovery (97.96-103.39%) and reproducibility (RSD, n=5; 3.3% for eleutheroside B, 4.6% for eleutheroside E). ILUAE was an efficient, rapid and simple sample preparation technique that showed high reproducibility and was environmental friendly. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Optimization of lignin production from empty fruit bunch via liquefaction with ionic liquid.

    PubMed

    Sidik, Dilaeleyana Abu Bakar; Ngadi, Norzita; Amin, Nor Aishah Saidina

    2013-05-01

    The production of lignin from empty fruit bunch (EFB) has been carried out using liquefaction method with 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) ionic liquid (IL), in presence of sulfuric acid (H2SO4) as a catalyst. Response surface methodology (RSM) based on a factorial Central Composite Design (CCD) was employed to identify the optimum condition for lignin yield. The result indicated that the second order model was adequate for all the independent variables on the response with R(2)=0.8609. The optimum temperature, time, ionic liquid to EFB ratio, and catalyst concentration were 150.5 °C, 151 min, 3:1 wt/wt and 4.73 wt%, respectively for lignin yield=26.6%. The presence of lignin liquefied product was confirmed by UV-Vis and FTIR analysis. It was also demonstrated lignin extraction from lignocellulosic using recycled IL gave sufficient performance. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Nonaqueous microemulsions based on n,n'-alkylimidazolium alkylsulfate ionic liquids.

    PubMed

    Rojas, Oscar; Tiersch, Brigitte; Rabe, Christian; Stehle, Ralf; Hoell, Armin; Arlt, Bastian; Koetz, Joachim

    2013-06-11

    The ternary system composed of the ionic liquid surfactant (IL-S) 1-butyl-3-methylimidazolium dodecylsulfate ([Bmim][DodSO4]), the room temperature ionic liquid (RTIL) 1-ethyl-3-methylimidazolium ethylsulfate ([Emim][EtSO4]), and toluene has been investigated. Three major mechanisms guiding the structure of the isotropic phase were identified by means of conductometric experiments, which have been correlated to the presence of oil-in-IL, bicontinuous, and IL-in-oil microemulsions. IL-S forms micelles in toluene, which swell by adding RTIL as to be shown by dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS) experiments. Therefore, it is possible to form water-free IL-in-oil reverse microemulsions ≤10 nm in size as a new type of nanoreactor.

  11. Electrochemical deposition of ultrathin ruthenium films on Au(1 1 1) from an ionic liquid

    NASA Astrophysics Data System (ADS)

    Mann, O.; Freyland, W.; Raz, O.; Ein-Eli, Y.

    2008-07-01

    We report the first investigation of ruthenium electrodeposition on Au(1 1 1) from an ionic liquid, 1-butyl-3-methylimidazolium dicyanamide, which exhibits sufficient solubility of RuCl 3 at room temperature. Employing cyclic voltammetry and in situ electrochemical scanning tunneling microscopy (EC-STM) we find that Ru(IV)-complex formation is a necessary prerequisite for Ru metal deposition from this ionic liquid. The corresponding oxidation reaction occurs at an anodic potential of ˜0.6 V vs. Pt/Pt(II). Thin Ru films of ˜5 nm average thickness and with a relatively homogeneous morphology have been grown with a very slow growth rate of 0.1 nm min -1. The metallic nature of these films is proven by X-ray photoelectron spectroscopy.

  12. Comparative Investigation of the Ionicity of Aprotic and Protic Ionic Liquids in Molecular Solvents by using Conductometry and NMR Spectroscopy.

    PubMed

    Thawarkar, Sachin; Khupse, Nageshwar D; Kumar, Anil

    2016-04-04

    Electrical conductivity (σ), viscosity (η), and self-diffusion coefficient (D) measurements of binary mixtures of aprotic and protic imidazolium-based ionic liquids with water, dimethyl sulfoxide, and ethylene glycol were measured from 293.15 to 323.15 K. The temperature dependence study reveals typical Arrhenius behavior. The ionicities of aprotic ionic liquids were observed to be higher than those of protic ionic liquids in these solvents. The aprotic ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate, [bmIm][BF4 ], displays 100 % ionicity in both water and ethylene glycol. The protic ionic liquids in both water and ethylene glycol are classed as good ionic candidates, whereas in DMSO they are classed as having a poor ionic nature. The solvation dynamics of the ionic species of the ionic liquids are illustrated on the basis of the (1) H NMR chemical shifts of the ionic liquids. The self-diffusion coefficients D of the cation and anion of [HmIm][CH3 COO] in D2 O and in [D6 ]DMSO are determined by using (1) H nuclei with pulsed field gradient spin-echo NMR spectroscopy.

  13. Ionic liquids: determination of their aqueous content using differential scanning calorimeter equipment, chaotic parameters and a radial basis network model.

    PubMed

    Torrecilla, José S; Rojo, Ester; Domínguez, Juan C; Rodríguez, Francisco

    2010-06-15

    A new computerized approach to the determination of water in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide, 1-butyl-3-methylimidazolium hexafluorophosfate and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ionic liquids (ILs) using the differential scanning calorimeter (DSC) scans of their mixtures with water is presented here. This approach consists of a combination of chaotic algorithms and a radial basis network (RBN). The data collected (heat flow signal) from DSC scans of ILs and water mixtures are used to calculate six chaotic parameters (two Liapunov exponents, two correlation parameters and two fractal dimensions), and then, these values are transferred into an RBN trained computer for modeling and estimating output. The predicted results using the RBN were compared with the measurements of water content carried out by the Karl Fischer technique and the difference between the real and predicted values was less than 0.05 and 4.9% in the internal and external validation, respectively. Such an integrated chaotic parameters (CPs)/RBN system is capable of detecting and quantifying water content in the aforementioned ILs, based on the created models and patterns, without any previous knowledge of this thermal process.

  14. Advanced two-photon photolithography for patterning of transparent, electrically conductive ionic liquid-polymer nanostructures

    NASA Astrophysics Data System (ADS)

    Bakhtina, Natalia A.; MacKinnon, Neil; Korvink, Jan G.

    2016-04-01

    A key challenge in micro- and nanotechnology is the direct patterning of functional structures. For example, it is highly desirable to possess the ability to create three-dimensional (3D), conductive, and optically transparent structures. Efforts in this direction have, to date, yielded less than optimal results since the polymer composites had low optical transparency over the visible range, were only slightly conductive, or incompatible with high resolution structuring. We have previously presented the novel cross-linkable, conductive, highly transparent composite material based on a photoresist (IP-L 780, OrmoComp, or SU-8) and the ionic liquid 1-butyl-3-methylimidazolium dicyanamide. Material patterning by conventional and two-photon photolithography has been demonstrated as proof-of-concept. Aiming to increase the resolution and to extend the spectrum of exciting applications we continued our research into identifying new ionic liquid - polymer composites. In this paper, we report the precise 3D single-step structuring of optically transparent and electrically conductive ionic liquid - polymer nanostructures with the highest spatial resolution (down to 150 nm) achieved to date. This was achieved via the development of novel cross-linkable composite based on the photoresist IP-G 780 and the ionic liquid 1-butyl-3-methylimidazolium dicyanamide. The successful combination of the developed material with the advanced direct laser writing technique enabled the time- and cost-saving direct manufacturing of transparent, electrically conductive components. We believe that the excellent characteristics of the structured material will open a wider range of exciting applications.

  15. Ionic liquids behave as dilute electrolyte solutions

    PubMed Central

    Gebbie, Matthew A.; Valtiner, Markus; Banquy, Xavier; Fox, Eric T.; Henderson, Wesley A.; Israelachvili, Jacob N.

    2013-01-01

    We combine direct surface force measurements with thermodynamic arguments to demonstrate that pure ionic liquids are expected to behave as dilute weak electrolyte solutions, with typical effective dissociated ion concentrations of less than 0.1% at room temperature. We performed equilibrium force–distance measurements across the common ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C4mim][NTf2]) using a surface forces apparatus with in situ electrochemical control and quantitatively modeled these measurements using the van der Waals and electrostatic double-layer forces of the Derjaguin–Landau–Verwey–Overbeek theory with an additive repulsive steric (entropic) ion–surface binding force. Our results indicate that ionic liquids screen charged surfaces through the formation of both bound (Stern) and diffuse electric double layers, where the diffuse double layer is comprised of effectively dissociated ionic liquid ions. Additionally, we used the energetics of thermally dissociating ions in a dielectric medium to quantitatively predict the equilibrium for the effective dissociation reaction of [C4mim][NTf2] ions, in excellent agreement with the measured Debye length. Our results clearly demonstrate that, outside of the bound double layer, most of the ions in [C4mim][NTf2] are not effectively dissociated and thus do not contribute to electrostatic screening. We also provide a general, molecular-scale framework for designing ionic liquids with significantly increased dissociated charge densities via judiciously balancing ion pair interactions with bulk dielectric properties. Our results clear up several inconsistencies that have hampered scientific progress in this important area and guide the rational design of unique, high–free-ion density ionic liquids and ionic liquid blends. PMID:23716690

  16. Ionic liquids behave as dilute electrolyte solutions.

    PubMed

    Gebbie, Matthew A; Valtiner, Markus; Banquy, Xavier; Fox, Eric T; Henderson, Wesley A; Israelachvili, Jacob N

    2013-06-11

    We combine direct surface force measurements with thermodynamic arguments to demonstrate that pure ionic liquids are expected to behave as dilute weak electrolyte solutions, with typical effective dissociated ion concentrations of less than 0.1% at room temperature. We performed equilibrium force-distance measurements across the common ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C4mim][NTf2]) using a surface forces apparatus with in situ electrochemical control and quantitatively modeled these measurements using the van der Waals and electrostatic double-layer forces of the Derjaguin-Landau-Verwey-Overbeek theory with an additive repulsive steric (entropic) ion-surface binding force. Our results indicate that ionic liquids screen charged surfaces through the formation of both bound (Stern) and diffuse electric double layers, where the diffuse double layer is comprised of effectively dissociated ionic liquid ions. Additionally, we used the energetics of thermally dissociating ions in a dielectric medium to quantitatively predict the equilibrium for the effective dissociation reaction of [C4mim][NTf2] ions, in excellent agreement with the measured Debye length. Our results clearly demonstrate that, outside of the bound double layer, most of the ions in [C4mim][NTf2] are not effectively dissociated and thus do not contribute to electrostatic screening. We also provide a general, molecular-scale framework for designing ionic liquids with significantly increased dissociated charge densities via judiciously balancing ion pair interactions with bulk dielectric properties. Our results clear up several inconsistencies that have hampered scientific progress in this important area and guide the rational design of unique, high-free-ion density ionic liquids and ionic liquid blends.

  17. Selective extraction of emerging contaminants from water samples by dispersive liquid-liquid microextraction using functionalized ionic liquids.

    PubMed

    Yao, Cong; Li, Tianhao; Twu, Pamela; Pitner, William R; Anderson, Jared L

    2011-03-25

    Functionalized ionic liquids containing the tris(pentafluoroethyl)trifluorophosphate (FAP) anion were used as extraction solvents in dispersive liquid-liquid microextraction (DLLME) for the extraction of 14 emerging contaminants from water samples. The extraction efficiencies and selectivities were compared to those of an in situ IL DLLME method which uses an in situ metathesis reaction to exchange 1-butyl-3-methylimidazolium chloride (BMIM-Cl) to 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide (BMIM-NTf(2)). Compounds containing tertiary amine functionality were extracted with high selectivity and sensitivity by the 1-(6-amino-hexyl)-1-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate (HNH(2)MPL-FAP) IL compared to other FAP-based ILs and the BMIM-NTf(2) IL. On the other hand, polar or acidic compounds without amine groups exhibited higher enrichment factors using the BMIM-NTf(2) IL. The detection limits for the studied analytes varied from 0.1 to 55.1 μg/L using the traditional IL DLLME method with the HNH(2)MPL-FAP IL as extraction solvent, and from 0.1 to 55.8 μg/L using in situ IL DLLME method with BMIM-Cl+LiNTf(2) as extraction solvent. A 93-fold decrease in the detection limit of caffeine was observed when using the HNH(2)MPL-FAP IL compared to that obtained using in situ IL DLLME method. Real water samples including tap water and creek water were analyzed with both IL DLLME methods and yielded recoveries ranging from 91% to 110%.

  18. Cryogenic neon matrix-isolation FTIR spectroscopy of evaporated ionic liquids: geometrical structure of cation-anion 1:1 pair in the gas phase.

    PubMed

    Akai, Nobuyuki; Parazs, David; Kawai, Akio; Shibuya, Kazuhiko

    2009-04-09

    Low-temperature infrared spectra of thermally evaporated ionic liquids, 1-ethyl- and 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide and bis(trifluoromethanesulfonyl)amide have been measured in a cryogenic Ne matrix. The experimental IR spectrum of bis(trifluoromethanesulfonyl)amide can be reproduced theoretically by not B3LYP/6-31G* but MP2/6-31G* calculation, which suggests that the vibrational analysis for ionic liquids composed of bis(trifluoromethanesulfonyl)imide anion would be more successfully performed using the MP2 calculation. By comparison of the matrix-isolation spectra of the ionic liquids with the MP2 calculation, their geometrical structures in the gas phase are determined to be of C(2-position)-H(+)...N(-) interaction structure, which corresponds to the geometry of the energetically second-lowest ion-pair structure. The present study may provide a valuable clue to understand a vaporization mechanism of ionic liquid.

  19. Rapid carbonation for calcite from a solid-liquid-gas system with an imidazolium-based ionic liquid.

    PubMed

    Ibrahim, Abdul-Rauf; Vuningoma, Jean Bosco; Huang, Yan; Wang, Hongtao; Li, Jun

    2014-06-25

    Aqueous carbonation of Ca(OH)2 is a complex process that produces calcite with scalenohedral calcite phases and characterized by inadequate carbonate species for effective carbonation due to the poor dissolution of CO2 in water. Consequently, we report a solid-liquid-gas carbonation system with an ionic liquid (IL), 1-butyl-3-methylimidazolium bromide, in view of enhancing the reaction of CO2 with Ca(OH)2. The use of the IL increased the solubility of CO2 in the aqueous environment and enhanced the transport of the reactive species (Ca2+ and CO32-) and products. The presence of the IL also avoided the formation of the CaCO3 protective and passivation layer and ensured high carbonation yields, as well as the production of stoichiometric rhombohedral calcite phases in a short time.

  20. Rapid Carbonation for Calcite from a Solid-Liquid-Gas System with an Imidazolium-Based Ionic Liquid

    PubMed Central

    Ibrahim, Abdul-Rauf; Vuningoma, Jean Bosco; Huang, Yan; Wang, Hongtao; Li, Jun

    2014-01-01

    Aqueous carbonation of Ca(OH)2 is a complex process that produces calcite with scalenohedral calcite phases and characterized by inadequate carbonate species for effective carbonation due to the poor dissolution of CO2 in water. Consequently, we report a solid-liquid-gas carbonation system with an ionic liquid (IL), 1-butyl-3-methylimidazolium bromide, in view of enhancing the reaction of CO2 with Ca(OH)2. The use of the IL increased the solubility of CO2 in the aqueous environment and enhanced the transport of the reactive species (Ca2+ and CO32−) and products. The presence of the IL also avoided the formation of the CaCO3 protective and passivation layer and ensured high carbonation yields, as well as the production of stoichiometric rhombohedral calcite phases in a short time. PMID:24968273

  1. The Effect of Water on Rheology of Native Cellulose/Ionic Liquids Solutions.

    PubMed

    Nazari, Behzad; Utomo, Nyalaliska W; Colby, Ralph H

    2017-09-11

    Cellulose coagulates upon adding water to its solutions in ionic liquids. Although cellulose remains in solution with much higher water contents, here we report the effect of 0-3 wt % water on solution rheology of cellulose in 1-butyl-3-methylimidazolium chloride and 1-ethyl-3-methylimidazolium acetate. Fourier transform infrared spectroscopy, thermal gravimetric analysis, and polarized light microscopy were also used to study water absorbance to the solutions. Tiny amounts of water (0.25 wt %) can significantly affect the rheological properties of the solutions, imparting a yield stress, while dry solutions appear to be ordinary viscoelastic liquids. The yield stress grows linearly with water content and saturates at a level that increases with the square of cellulose content. Annealing the solutions containing small amounts of water at 80 °C for 20 min transforms the samples to the fully dissolved "dry" state.

  2. Can the tricyanomethanide anion improve CO2 absorption by acetate-based ionic liquids?

    PubMed

    Lepre, L F; Szala-Bilnik, J; Pison, L; Traïkia, M; Pádua, A A H; Ando, R A; Costa Gomes, M F

    2017-05-17

    Carbon dioxide absorption by mixtures of two ionic liquids with a common cation-1-butyl-3-methylimidazolium acetate, [C4C1Im][OAc], and 1-butyl-3-methylimidazolium tricyanomethanide, [C4C1Im][C(CN)3]-was determined experimentally at pressures below atmospheric pressure as a function of temperature between 303 K and 343 K, and at 303 K as a function of pressure up to 10 bar. It is observed that the absorption of carbon dioxide decreases with increasing tricyanomethanide anion concentration and with increasing temperature, showing a maximum of 0.4 mole fraction of carbon dioxide in pure [C4C1Im][OAc] at 303 K. At this temperature, the CO2 absorption in the mixtures [C4C1Im][OAc](1-x)[C(CN)3]x is approximately the mole-fraction average of that in the pure ionic liquids. By applying an appropriate thermodynamic treatment, after identification of the species in solution, it was possible to calculate both the equilibrium constant, Keq, and Henry's law constant, KH, in the different mixtures studied thus obtaining an insight into the relative contribution of chemical and physical absorption of the gas. It is shown that chemical sorption proceeds through a 1 : 2 stoichiometry between CO2 and acetate-based ionic liquid. The presence of the C(CN)3(-) anion does not significantly affect the chemical reaction of the gas with the solvent (Keq = 75 ± 2 at 303 K) but leads to lower Henry's law constants (from KH = 77.8 ± 0.6 bar to KH = 49.5 ± 0.5 bar at 303 K), thus pointing towards larger physical absorption of the gas. The tricyanomethanide anion considerably improves the mass transfer by increasing the fluidity of the absorbent as proven by the larger diffusivities of all the ions when the concentration of the C(CN)3(-) anion increases in the mixtures.

  3. Characterization of pathogenic bacteria using ionic liquid via single drop microextraction combined with MALDI-TOF MS.

    PubMed

    Ahmad, Faheem; Wu, Hui-Fen

    2011-10-07

    The present research was based on the single drop microextraction (SDME) approach using an ionic liquid drop to extract bacteria from aqueous samples for characterization of pathogenic bacteria by MALDI-TOF MS. The SDME of bacteria from aqueous samples was successfully achieved by using platinum nanoparticles mixed in ionic liquid (IL, 1-butyl-3-methylimidazolium hexafluorophosphate) and IL alone as the extraction drops. The IL was used as liquid drops by SDME to obtain protein profiles from bacteria. Significant numbers of biomarker protein peaks of bacteria were identified from target biological samples. The IL also significantly improved the signal reproducibility of spectra using the SDME approach combined with MALDI-TOF MS. Thus, the present technique was successfully applied to detect pathogenic bacteria at low concentrations of 10(6) cfu mL(-1) from aqueous suspensions. The selected bacteria viz., Escherichia coli and Serratia marcescens were used as target biological sample.

  4. Development of sample preparation method for isoliquiritigenin, liquiritin, and glycyrrhizic acid analysis in licorice by ionic liquids-ultrasound based extraction and high-performance liquid chromatography detection.

    PubMed

    Yang, Lei; Li, Li-li; Liu, Ting-ting; Zu, Yuan-gang; Yang, Feng-jian; Zhao, Chun-jian; Zhang, Lin; Chen, Xiao-qiang; Zhang, Zhong-hua

    2013-05-01

    An ionic liquid-based ultrasonic-assisted extraction (ILUAE) method had been used for the effective extraction of isoliquiritigenin (IQ), liquiritin (LQ) and glycyrrhizic acid (GA) from licorice. The ionic liquids with different cations and anions were investigated in this work and 0.5 M 1-butyl-3-methylimidazolium bromide solution was selected as solvent. In addition, the technical parameters including soaking time, solid-liquid ratio, ultrasonic power and time were optimized. Compared with the conventional solvent extraction, the proposed approach exhibited higher efficiency, which indicated the ILUAE was an efficient, rapid and simple sample preparation technique. There was no degradation of the target analytes had been observed at the optimum conditions which was evidenced by the stability studies performed with standard of IQ, LQ and GA. The proposed method also showed high reproducibility and was environmental friendly.

  5. Screening of lignan patterns in Schisandra species using ultrasonic assisted temperature switch ionic liquid microextraction followed by UPLC-MS/MS analysis.

    PubMed

    Dong, Wei; Yu, Shuijing; Deng, Yangwu; Pan, Tao

    2016-01-01

    The ultrasonic assisted temperature-switch ionic liquid microextraction (UATS-ILME) has been successfully applied in extracting of seven lignans from Schisandra. 1-Butyl-3-methylimidazolium tetrafluoroborate ([C4MIM][BF4]) aqueous solution was selected for extracting the target analytes in raw material at 80°C. The lignans were deposited into a single drop by in situ forming 1-butyl-3-methylimidazolium hexafluorophosphate ([C4MIM][PF6]) by cooling down to 0°C and centrifuging for 10min. The extracts were analyzed by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) in a robust multiple-reaction monitoring (MRM) mode in five minutes. Meanwhile, the proposed method was validated and successfully applied to the determination of seven lignans in twelve Schisandra species. The results indicated that UATS-ILME combined with UPLC-MS/MS is a powerful and practical tool, which has great potential for comprehensive quality control of herbal medicines.

  6. Molecular dynamics simulation of the behaviour of water in nano-confined ionic liquid-water mixtures

    NASA Astrophysics Data System (ADS)

    Docampo-Álvarez, B.; Gómez-González, V.; Montes-Campos, H.; Otero-Mato, J. M.; Méndez-Morales, T.; Cabeza, O.; Gallego, L. J.; Lynden-Bell, R. M.; Ivaništšev, V. B.; Fedorov, M. V.; Varela, L. M.

    2016-11-01

    This work describes the behaviour of water molecules in 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid under nanoconfinement, between graphene sheets. By means of molecular dynamics simulations, the adsorption of water molecules at the graphene surface is studied. A depletion of water molecules in the vicinity of the neutral and negatively charged graphene surfaces, and their adsorption at the positively charged surface are observed in line with the preferential hydration of the ionic liquid anions. The findings are appropriately described using a two-level statistical model. The confinement effect on the structure and dynamics of the mixtures is thoroughly analyzed using the density and the potential of mean force profiles, as well as by the vibrational densities of the states of water molecules near the graphene surface. The orientation of water molecules and the water-induced structural transitions in the layer closest to the graphene surface are also discussed.

  7. Biodiesel production using alkaline ionic liquid and adopted as lubricity additive for low-sulfur diesel fuel.

    PubMed

    Luo, Hui; Fan, Weiyu; Li, Yang; Nan, Guozhi

    2013-07-01

    Preparation of biodiesel from vegetable oils, such as rapeseed oil, soybean oil and sunflower oil, catalyzed by an alkaline ionic liquid 1-butyl-3-methylimidazolium imidazolide ([Bmim]Im) was investigated in this work. The results demonstrated that [Bmim]Im exhibited high activity and the yield of biodiesel was up to 95% or more when molar ratio of methanol to vegetable oil was 6:1, ionic liquid dosage was 6 wt.%, reaction temperature was 60°C, and reaction time was 60 min. After [Bmim]Im was used for the sixth time, the yield of biodiesel still remained at about 95%. The effects of the biodiesels on the lubricity of low-sulfur diesel fuel were also investigated using the High Frequency Reciprocating Rig method, and the results showed that sunflower biodiesel and soybean biodiesel had higher lubrication performance than that of rapeseed biodiesel. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Ionic liquid, glass or crystalline solid? Structures and thermal behaviour of (C4mim)2CuCl3.

    PubMed

    Zürner, Philipp; Schmidt, Horst; Bette, Sebastian; Wagler, Jörg; Frisch, Gero

    2016-02-28

    The ionic liquid (C4mim)2CuCl3 was synthesised from a mixture of copper(i) chloride and 1-butyl-3-methylimidazolium chloride (C4mimCl) and investigated using crystallographic and thermoanalytical methods. In the crystalline state, the compound consists of C4mim(+) cations and triangular [CuCl3](2-) anions and forms three different modifications, which are connected through phase transitions at 227 and 203 K. The high and intermediate temperature phases crystallise in the space group C2, whereas the low temperature phase exhibits the space group P21. The three crystal structures are related through an isomorphic and a klassengleiche symmetry transition, respectively. The solid undergoes congruent melting at 320 K. The enthalpy of fusion was determined to be 25.7 kJ mol(-1). The melting process is irreversible and the ionic liquid can be supercooled to its glass transition at 221 K.

  9. Ionic liquid as a promising biobased green solvent in combination with microwave irradiation for direct biodiesel production.

    PubMed

    Wahidin, Suzana; Idris, Ani; Shaleh, Sitti Raehanah Muhamad

    2016-04-01

    The wet biomass microalgae of Nannochloropsis sp. was converted to biodiesel using direct transesterification (DT) by microwave technique and ionic liquid (IL) as the green solvent. Three different ionic liquids; 1-butyl-3-metyhlimidazolium chloride ([BMIM][Cl], 1-ethyl-3-methylimmidazolium methyl sulphate [EMIM][MeSO4] and 1-butyl-3-methylimidazolium trifluoromethane sulfonate [BMIM][CF3SO3]) and organic solvents (hexane and methanol) were used as co-solvents under microwave irradiation and their performances in terms of percentage disruption, cell walls ruptured and biodiesel yields were compared at different reaction times (5, 10 and 15 min). [EMIM][MeSO4] showed highest percentage cell disruption (99.73%) and biodiesel yield (36.79% per dried biomass) after 15 min of simultaneous reaction. The results demonstrated that simultaneous extraction-transesterification using ILs and microwave irradiation is a potential alternative method for biodiesel production.

  10. Nacre-like calcium carbonate controlled by ionic liquid/graphene oxide composite template.

    PubMed

    Yao, Chengli; Xie, Anjian; Shen, Yuhua; Zhu, Jinmiao; Li, Hongying

    2015-06-01

    Nacre-like calcium carbonate nanostructures have been mediated by an ionic liquid (IL)-graphene oxide (GO) composite template. The resultant crystals were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, and X-ray powder diffractometry (XRD). The results showed that either 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4) or graphene oxide can act as a soft template for calcium carbonate formation with unusual morphologies. Based on the time-dependent morphology changes of calcium carbonate particles, it is concluded that nacre-like calcium carbonate nanostructures can be formed gradually utilizing [BMIM]BF4/GO composite template. During the process of calcium carbonate formation, [BMIM]BF4 acted not only as solvents but also as morphology templates for the fabrication of calcium carbonate materials with nacre-like morphology. Based on the observations, the possible mechanisms were also discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Surface segregation in binary mixtures of imidazolium-based ionic liquids

    NASA Astrophysics Data System (ADS)

    Souda, Ryutaro

    2010-09-01

    Surface composition of binary mixtures of room-temperature ionic liquids has been investigated using time-of-flight secondary ion mass spectrometry at room temperature over a wide composition range. The imidazolium cations with longer aliphatic groups tend to segregate to the surface, and a bis(trifluoromethanesulfonyl)imide anion (Tf 2N -) is enriched at the surface relative to hexafluorophosphate (PF 6-). The surface of an equimolar mixture of Li[Tf 2N] and 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF 6]) has a nominal composition of [bmim][Tf 2N] because of surface segregation and ligand exchange. The surface segregation of cations and anions is likely to result from alignment of specific ligand-exchanged molecules at the topmost surface layer to exclude more hydrophobic part of the molecules.

  12. Controlling hydrolysis reaction rates with binary ionic liquid mixtures by tuning hydrogen-bonding interactions.

    PubMed

    Weber, Cameron C; Masters, Anthony F; Maschmeyer, Thomas

    2012-02-16

    The ability of a binary ionic liquid (IL) system consisting of a phosphonium transition state analogue (TSA) and 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([BMIM][NTf(2)]) to accelerate the rate of the well-studied hydrolysis of a tert-alkyl picolinium salt by influencing the solvent structure was investigated. A significant rate enhancement was observed in the presence of the TSA; however, comparison with other cations illustrated that this enhancement was not unique to the chosen TSA. Instead, the rate enhancements were correlated with the dilution of hydrogen bonding by the added cations. This phenomenon was further examined by the use of 1-butyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonyl)imide ([BMMIM][NTf(2)]) as a cosolvent and the use of Reichardt's dye to measure the extent of hydrogen bonding on solutes in these systems. The rate increases are rationalized in terms of weaker hydrogen bonding from the solvent system to water.

  13. Pretreatment of sugarcane bagasse by acid-catalysed process in aqueous ionic liquid solutions.

    PubMed

    Zhang, Zhanying; O'Hara, Ian M; Doherty, William O S

    2012-09-01

    A biomass pretreatment process was developed using acidified ionic liquid (IL) solutions containing 10-30% water. Pretreatment of sugarcane bagasse at 130°C for 30 min by aqueous 1-butyl-3-methylimidazolium chloride (BMIMCl) solution containing 1.2% HCl resulted in a glucan digestibility of 94-100% after 72 h of enzymatic hydrolysis. HCl was found to be a more effective catalyst than H(2)SO(4) or FeCl(3). Increasing acid concentration (from 0.4% to 1.2%) and reaction temperature (from 90 to 130°C) increased glucan digestibility. The glucan digestibility of solid residue obtained with the acidified BMIMCl solution that was re-used for three times was >97%. The addition of water to ILs for pretreatment could significantly reduce IL solvent costs and allow for increased biomass loadings, making the pretreatment by ILs a more economic proposition. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. An electrochemical fungicide pyrimethanil sensor based on carbon nanotubes/ionic-liquid construction modified electrode.

    PubMed

    Yang, Jichun; Wang, Qiong; Zhang, Minhui; Zhang, Shuming; Zhang, Lei

    2015-11-15

    In this study, a simple, rapid, sensitive and environmentally friendly electroanalytical detection method for pyrimethanil (PMT) was developed, which was based on multi-walled carbon nanotubes (MWCNTs) and ionic liquids (IL) 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) modified glassy carbon electrode (GCE). MWCNTs-IL modified electrode significantly enhanced the oxidation peak current of PMT by combining the excellent electrochemical properties of MWCNTs and IL, suggesting that the modified electrode can remarkably improve the sensitivity of PMT detection. Under the optimum conditions, this electrochemical sensor exhibited a linear concentration range for PMT of 1.0 × 10(-7)-1.0 × 10(-4) mol L(-1) and the detection limit was 1.6 × 10(-8) mol L(-1) (S/N = 3). The fabricated electrode showed good reproducibility, stability and anti-interference, and also it was successfully employed to detect PMT in real samples. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. The accurate estimation of physicochemical properties of ternary mixtures containing ionic liquids via artificial neural networks.

    PubMed

    Cancilla, John C; Díaz-Rodríguez, Pablo; Matute, Gemma; Torrecilla, José S

    2015-02-14

    The estimation of the density and refractive index of ternary mixtures comprising the ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate, 2-propanol, and water at a fixed temperature of 298.15 K has been attempted through artificial neural networks. The obtained results indicate that the selection of this mathematical approach was a well-suited option. The mean prediction errors obtained, after simulating with a dataset never involved in the training process of the model, were 0.050% and 0.227% for refractive index and density estimation, respectively. These accurate results, which have been attained only using the composition of the dissolutions (mass fractions), imply that, most likely, ternary mixtures similar to the one analyzed, can be easily evaluated utilizing this algorithmic tool. In addition, different chemical processes involving ILs can be monitored precisely, and furthermore, the purity of the compounds in the studied mixtures can be indirectly assessed thanks to the high accuracy of the model.

  16. Poly(ethylene oxide) Mushrooms Adsorbed at Silica-Ionic Liquid Interfaces Reduce Friction.

    PubMed

    Sweeney, James; Webber, Grant B; Atkin, Rob

    2016-03-01

    The adsorbed layer conformation and lubricity of 35, 100, and 300 kDa PEO adsorbed to ionic liquid (IL)-silica interfaces from 0.01 wt % solutions have been investigated using colloid probe atomic force microscopy. The ILs used were propylammonium nitrate (PAN) and 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]), which are protic and aprotic ILs, respectively. Normal force curves reveal steric interactions consistent with adsorbed polymer layers which are best fit using the mushroom model. Friction measurements show that the adsorbed polymer layer markedly reduces friction compared to surfaces sliding in the pure ILs and that lubricity increases with polymer length. When polymer is adsorbed to the sliding surfaces, friction is controlled by the creation and disruption of intermolecular interactions between entangled chains and the dragging of polymer chains through the interpenetration region. These experiments show that added polymer can reduce friction while maintaining the useful properties of ILs as lubricants.

  17. Trivalent actinide and lanthanide separations using tetraalkyldiglycolamides (TCnDGA) in molecular and ionic liquid diluents

    SciTech Connect

    Bruce J. Mincher; Robert V. Fox; Mary E. Mincher; Chien M. Wai

    2014-09-01

    The use of the diglycolamide, tetrabutyldiglycolamide was investigated for intergroup separations of the lanthanides, focusing especially on those lanthanides (Y, Ce, Eu, Tb, Dy, Er, and Yb) found in lighting phosphors. Tetrabutyldiglycolamide extraction efficiency for the lanthanides varied depending on whether the diluent was the conventional molecular diluent 1-octanol, the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)-imide, or a mixture of the two. This was attributed to extraction of either neutral, cationic or anionic lanthanide metal complexes with nitrate ion. Based on the batch contact solvent extraction results measured here, a series of extractions providing product streams containing separated Y, Ce, Eu, Tb/Dy, and Er/Yb are proposed.

  18. Understanding changes in cellulose crystalline structure of lignocellulosic biomass during ionic liquid pretreatment by XRD.

    PubMed

    Zhang, Jiafu; Wang, Yixun; Zhang, Liye; Zhang, Ruihong; Liu, Guangqing; Cheng, Gang

    2014-01-01

    X-ray diffraction (XRD) was used to understand the interactions of cellulose in lignocellulosic biomass with ionic liquids (ILs). The experiment was designed in such a way that the process of swelling and solubilization of crystalline cellulose in plant cell walls was followed by XRD. Three different feedstocks, switchgrass, corn stover and rice husk, were pretreated using 1-butyl-3-methylimidazolium acetate ([C4mim][OAc]) at temperatures of 50-130°C for 6h. At a 5 wt.% biomass loading, increasing pretreatment temperature led to a drop in biomass crystallinity index (CrI), which was due to swelling of crystalline cellulose. After most of the crystalline cellulose was swollen with IL molecules, a low-order structure was found in the pretreated samples. Upon further increasing temperature, cellulose II structure started to form in the pretreated biomass samples as a result of solubilization of cellulose in [C4mim][OAc] and subsequent regeneration.

  19. Ionic liquids as novel solvents for biosynthesis of octenyl succinic anhydride-modified waxy maize starch.

    PubMed

    Li, Dandan; Zhang, Xiwen; Tian, Yaoqi

    2016-05-01

    Biosynthesis of octenyl succinic anhydride (OSA) starch was investigated using ionic liquids (ILs) as reaction media. Waxy maize starch was pretreated in 1-butyl-3-methylimidazolium chlorine and then esterified with OSA in 1-octyl-3-methylimidazolium nitrate by using Novozyme 435 as catalyst. The degree of substitution of OSA starch reached 0.0130 with 5 wt% starch concentration and 1 wt% lipase dosage based on ILs weight at 50 °C for 3h. The formation of OSA starch was confirmed by fourier transform infrared spectroscopy. Scanning electron microscopy and X-ray diffraction revealed that the morphology and crystal structure of starch were significantly destroyed. Thermogravimetric analysis showed that esterification decreased the thermal stability of starch. The successful lipase-catalyzed synthesis of OSA starch in ILs suggests that ILs are potential replacement of traditional organic solvents for starch ester biosynthesis. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Ultrasound-assisted ionic liquid-based dispersive liquid-liquid microextraction for preconcentration of patent blue V and its determination in food samples by UV-visible spectrophotometry.

    PubMed

    Unsal, Yunus Emre; Soylak, Mustafa; Tuzen, Mustafa

    2015-04-01

    Ultrasound-assisted ionic liquid-based dispersive liquid-liquid microextraction procedure (UA-IL-DLLME) was developed for determination of trace levels of patent blue V prior to its determination by UV-visible spectrophotometry. Patent blue V was extracted from 25-mL sample into a 100-μL volume of ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]), with the aid of sonication in an ultrasonic bath. Several variables affecting microextraction efficiency were optimized. Under the optimum experimental conditions, the detection limit (3 s) was 0.68 μg L(-1), and the preconcentration factor was 100. The relative standard deviation for six replicate determinations of patent blue V was 4.5%. The method was applied to the determination of patent blue V in food samples. The proposed procedure is effective, very simple, and fast.

  1. Understanding positive and negative deviations in polarity of ionic liquid mixtures by pseudo-solvent approach.

    PubMed

    Beniwal, Vijay; Kumar, Anil

    2016-08-24

    Physico-chemical properties of liquid mixtures in general display large deviations from linear behaviour, arising out of complex specific and non-specific intermolecular interactions. The polarity of liquid mixtures displaying large positive and negative deviations can be minimized and linear mixing can be achieved in liquids using a pseudo-solvent methodology. The work described herein is designed to investigate the influence of different physical parameters on the linear pseudo-solvent composition in ionic liquid mixtures. For this purpose, we have determined the deviations from linearity, ΔE values (defined as given by ) for binary mixtures of a variety of ionic liquids, including two molecular solvents, DMSO and formamide. Firstly, the investigations were carried out in three 1-butyl-3-methylimidazolium cation based aprotic ionic liquids and the roles of anionic structure and hydrogen bond acceptor basicities (β values) of the ionic liquids were determined. The influence of the cationic structure, i.e., the hydrogen bond donor acidity (α values) and non-associative nature of the ionic liquids, was determined using C2-methylated analogs, 1-butyl-2,3-dimethylimidazolium cation based ionic liquids. The role of the protic nature of ionic liquids was studied in two protic ionic liquids, viz., 1-methylimidazolium formate and 1-methylimidazolium acetate. The effects of the temperature, pseudo-solvent structure and solvatochromic probe structure on the ΔE values were also explored.

  2. Nanodroplet cluster formation in ionic liquid microemulsions.

    PubMed

    Gao, Yanan; Voigt, Andreas; Hilfert, Liane; Sundmacher, Kai

    2008-08-04

    A common ionic liquid (IL), 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF(4)), is used as polar solvent to induce the formation of a reverse bmimBF(4)-in-toluene IL microemulsion with the aid of the nonionic surfactant Triton X-100. The swelling process of the microemulsion droplets by increasing bmimBF(4) content is detected by dynamic light scattering (DLS), conductivity, UV/Vis spectroscopy, and freeze-fracture transmission electron microscopy (FF-TEM). The results show that the microemulsion droplets initially formed are enlarged by the addition of bmimBF(4). However, successive addition of bmimBF(4) lead to the appearance of large-sized microemulsion droplet clusters (200-400 nm). NMR spectroscopic analysis reveal that the special structures and properties of bmimBF(4) and Triton X-100 together with the polar nature of toluene contribute to the formation of such self-assemblies. These unique self-assembled structures of IL-based microemulsion droplet clusters may have some unusual and unique properties with a number of interesting possibilities for potential applications.

  3. Surface modification using ionic liquid ion beams

    NASA Astrophysics Data System (ADS)

    Takaoka, Gikan H.; Hamaguchi, Takuya; Takeuchi, Mitsuaki; Ryuto, Hiromichi

    2014-12-01

    We developed an ionic liquid (IL) ion source using 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6) and produced IL ion beams by applying a high electric field between the tip and the extractor. Time-of-flight measurements showed that small cluster and fragment ions were contained in the positive and negative ion beams. The positive and negative cluster ions were deposited on Si(1 0 0) substrates. X-ray photoelectron spectroscopy measurements showed that the composition of the deposited layers was similar to that of an IL solvent. This suggests that a cation (A+) or an anion (B-) was attached to an IL cluster (AB)n, resulting in the formation of positive cluster ions (AB)nA+ or negative cluster ions (AB)nB-, respectively. The surfaces of the IL layers deposited on Si(1 0 0) substrates were flat at an atomic level for positive and negative cluster ion irradiation. Moreover, the contact angles of the deposited layers were similar to that of the IL solvent. Thus, surface modification of Si(1 0 0) substrates was successfully demonstrated with BMIM-PF6 cluster ion beams.

  4. Supported Ionic Liquid Membranes and Ion-Jelly® Membranes with [BMIM][DCA]: Comparison of Its Performance for CO2 Separation.

    PubMed

    Couto, Ricardo; Neves, Luísa; Simões, Pedro; Coelhoso, Isabel

    2015-01-14

    In this work, a supported ionic liquid membrane (SILM) was prepared by impregnating a PVDF membrane with 1-butyl-3-methylimidazolium dicyanamide ([BMIM][DCA]) ionic liquid. This membrane was tested for its permeability to pure gases (CO2, N2 and O2) and ideal selectivities were calculated. The SILM performance was also compared to that of Ion-Jelly® membranes, a new type of gelled membranes developed recently. It was found that the PVDF membrane presents permeabilities for pure gases similar or lower to those presented by the Ion-Jelly® membranes, but with increased ideal selectivities. This membrane presents also the highest ideal selectivity (73) for the separation of CO2 from N2 when compared with SILMs using the same PVDF support but with different ionic liquids.

  5. Supported Ionic Liquid Membranes and Ion-Jelly® Membranes with [BMIM][DCA]: Comparison of Its Performance for CO2 Separation

    PubMed Central

    Couto, Ricardo; Neves, Luísa; Simões, Pedro; Coelhoso, Isabel

    2015-01-01

    In this work, a supported ionic liquid membrane (SILM) was prepared by impregnating a PVDF membrane with 1-butyl-3-methylimidazolium dicyanamide ([BMIM][DCA]) ionic liquid. This membrane was tested for its permeability to pure gases (CO2, N2 and O2) and ideal selectivities were calculated. The SILM performance was also compared to that of Ion-Jelly® membranes, a new type of gelled membranes developed recently. It was found that the PVDF membrane presents permeabilities for pure gases similar or lower to those presented by the Ion-Jelly® membranes, but with increased ideal selectivities. This membrane presents also the highest ideal selectivity (73) for the separation of CO2 from N2 when compared with SILMs using the same PVDF support but with different ionic liquids. PMID:25594165

  6. Determining diffusion coefficients of ionic liquids by means of field cycling nuclear magnetic resonance relaxometry

    SciTech Connect

    Kruk, D.; Meier, R.; Rössler, E. A.; Rachocki, A.; Korpała, A.; Singh, R. K.

    2014-06-28

    Field Cycling Nuclear Magnetic Resonance (FC NMR) relaxation studies are reported for three ionic liquids: 1-ethyl-3- methylimidazolium thiocyanate (EMIM-SCN, 220–258 K), 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM-BF{sub 4}, 243–318 K), and 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF{sub 6}, 258–323 K). The dispersion of {sup 1}H spin-lattice relaxation rate R{sub 1}(ω) is measured in the frequency range of 10 kHz–20 MHz, and the studies are complemented by {sup 19}F spin-lattice relaxation measurements on BMIM-PF{sub 6} in the corresponding frequency range. From the {sup 1}H relaxation results self-diffusion coefficients for the cation in EMIM-SCN, BMIM-BF{sub 4}, and BMIM-PF{sub 6} are determined. This is done by performing an analysis considering all relevant intra- and intermolecular relaxation contributions to the {sup 1}H spin-lattice relaxation as well as by benefiting from the universal low-frequency dispersion law characteristic of Fickian diffusion which yields, at low frequencies, a linear dependence of R{sub 1} on square root of frequency. From the {sup 19}F relaxation both anion and cation diffusion coefficients are determined for BMIM-PF{sub 6}. The diffusion coefficients obtained from FC NMR relaxometry are in good agreement with results reported from pulsed- field-gradient NMR. This shows that NMR relaxometry can be considered as an alternative route of determining diffusion coefficients of both cations and anions in ionic liquids.

  7. Conductivity-Relaxation Relations in Nanocomposite Polymer Electrolytes Containing Ionic Liquid.

    PubMed

    Shojaatalhosseini, Mansoureh; Elamin, Khalid; Swenson, Jan

    2017-10-04

    In this study, we have used nanocomposite polymer electrolytes, consisting of poly(ethylene oxide) (PEO), δ-Al2O3 nanoparticles, and lithium bis(trifluoromethanesolfonyl)imide (LiTFSI) salt (with 4 wt % δ-Al2O3 and PEO:Li ratios of 16:1 and 8:1), and added different amounts of the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesolfonyl)imide (BMITFSI). The aim was to elucidate whether the ionic liquid is able to dissociate the Li-ions from the ether oxygens and thereby decouple the ionic conductivity from the segmental polymer dynamics. The results from DSC and dielectric spectroscopy show that the ionic liquid speeds up both the segmental polymer dynamics and the motion of the Li(+) ions. However, a close comparison between the structural (α) relaxation process, given by the segmental polymer dynamics, and the ionic conductivity shows that the motion of the Li(+) ions decouples from the segmental polymer dynamics at higher concentrations of the ionic liquid (≥20 wt %) and instead becomes more related to the viscosity of the ionic liquid. This decoupling increases with decreasing temperature. In addition to the structural α-relaxation, two more local relaxation processes, denoted β and γ, are observed. The β-relaxation becomes slightly faster at the highest concentration of the ionic liquid (at least for the lower salt concentration), whereas the γ-relaxation is unaffected by the ionic liquid, over the whole concentration range 0-40 wt %.

  8. Intermolecular vibrations and fast relaxations in supercooled ionic liquids

    NASA Astrophysics Data System (ADS)

    Ribeiro, Mauro C. C.

    2011-06-01

    Short-time dynamics of ionic liquids has been investigated by low-frequency Raman spectroscopy (4 < ω < 100 cm-1) within the supercooled liquid range. Raman spectra are reported for ionic liquids with the same anion, bis(trifluoromethylsulfonyl)imide, and different cations: 1-butyl-3-methylimidazolium, 1-hexyl-3-methylimidazolium, 1-butyl-1-methylpiperidinium, trimethylbutylammonium, and tributylmethylammonium. It is shown that low-frequency Raman spectroscopy provides similar results as optical Kerr effect (OKE) spectroscopy, which has been used to study intermolecular vibrations in ionic liquids. The comparison of ionic liquids containing aromatic and non-aromatic cations identifies the characteristic feature in Raman spectra usually assigned to librational motion of the imidazolium ring. The strength of the fast relaxations (quasi-elastic scattering, QES) and the intermolecular vibrational contribution (boson peak) of ionic liquids with non-aromatic cations are significantly lower than imidazolium ionic liquids. A correlation length assigned to the boson peak vibrations was estimated from the frequency of the maximum of the boson peak and experimental data of sound velocity. The correlation length related to the boson peak (˜19 Å) does not change with the length of the alkyl chain in imidazolium cations, in contrast to the position of the first-sharp diffraction peak observed in neutron and X-ray scattering measurements of ionic liquids. The rate of change of the QES intensity in the supercooled liquid range is compared with data of excess entropy, free volume, and mean-squared displacement recently reported for ionic liquids. The temperature dependence of the QES intensity in ionic liquids illustrates relationships between short-time dynamics and long-time structural relaxation that have been proposed for glass-forming liquids.

  9. Intermolecular vibrations and fast relaxations in supercooled ionic liquids.

    PubMed

    Ribeiro, Mauro C C

    2011-06-28

    Short-time dynamics of ionic liquids has been investigated by low-frequency Raman spectroscopy (4 < ω < 100 cm(-1)) within the supercooled liquid range. Raman spectra are reported for ionic liquids with the same anion, bis(trifluoromethylsulfonyl)imide, and different cations: 1-butyl-3-methylimidazolium, 1-hexyl-3-methylimidazolium, 1-butyl-1-methylpiperidinium, trimethylbutylammonium, and tributylmethylammonium. It is shown that low-frequency Raman spectroscopy provides similar results as optical Kerr effect (OKE) spectroscopy, which has been used to study intermolecular vibrations in ionic liquids. The comparison of ionic liquids containing aromatic and non-aromatic cations identifies the characteristic feature in Raman spectra usually assigned to librational motion of the imidazolium ring. The strength of the fast relaxations (quasi-elastic scattering, QES) and the intermolecular vibrational contribution (boson peak) of ionic liquids with non-aromatic cations are significantly lower than imidazolium ionic liquids. A correlation length assigned to the boson peak vibrations was estimated from the frequency of the maximum of the boson peak and experimental data of sound velocity. The correlation length related to the boson peak (∼19 Å) does not change with the length of the alkyl chain in imidazolium cations, in contrast to the position of the first-sharp diffraction peak observed in neutron and X-ray scattering measurements of ionic liquids. The rate of change of the QES intensity in the supercooled liquid range is compared with data of excess entropy, free volume, and mean-squared displacement recently reported for ionic liquids. The temperature dependence of the QES intensity in ionic liquids illustrates relationships between short-time dynamics and long-time structural relaxation that have been proposed for glass-forming liquids.

  10. First example of stepwise, zwitterionic mechanism for bicyclo[2.2.1]hept-5-ene (norbornene) formation process catalyzed by the 1-butyl-3-methylimidazolium cations.

    PubMed

    Jasiński, Radomir

    B3LYP/6-31++G(d) calculations indicated that the reaction of (2E)-3-phenyl-2-nitroprop-2-enenitrile with cyclopentadiene catalyzed by cations of 1,3-dialkylimidazolium ionic liquid shall not take place according to the classical scheme of one-step [2+4] Diels-Alder cycloaddition. Along the path finally leading to bicyclo[2.2.1]hept-5-ene (norbornene) with a nitro group in endo orientation, the process of bicarbocyclic skeleton formation shall take place according to the domino mechanism, via [2+4] heterocycloadduct. On the other hand, along the path leading finally to bicyclo[2.2.1]hept-5-ene with a nitro group in exo orientation, acyclic adduct with a zwitterionic nature is formed in the first reaction, which undergoes cyclisation next in the second step of the reaction.

  11. Evaluation of thermophysical properties of ionic liquids with polar solvent: a comparable study of two families of ionic liquids with various ions.

    PubMed

    Govinda, Varadhi; Attri, Pankaj; Venkatesu, Punnuru; Venkateswarlu, Ponneri

    2013-10-17

    In this work, we explore and compare the role of the ion effect on the thermophysical properties of two families of ionic liquids (ILs), namely, tetra-alkyl ammonium cation [R4N](+) with hydroxide [OH](-) anion and 1-alkyl-3-methyl imidazolium cation [amim](+) with different anions (chloride, methyl sulfate, and tetrafluoroborate), with polar solvent such as dimethylsulfoxide (DMSO) in the temperature range from 25 to 40 °C and over the whole concentration range of ILs. Two families of ILs, namely, tetramethyl ammonium hydroxide [(CH3)4N][OH] (TMAH), tetraethyl ammonium hydroxide [(C2H5)4N][OH] (TEAH), tetrapropyl ammonium hydroxide [(C3H7)4N][OH] (TPAH), and tetrabutyl ammonium hydroxide [(C4H9)4N][OH] (TBAH) from ammonium-based ILs and 1-ethyl-3-methylimidazolium chloride [Emim][Cl], 1-ethyl-3-methylimidazolium methylsulfate [Emim][MeSO4], 1-butyl-3-methylimidazolium tetrafluoroborate [Bmim][BF4], and 1-butyl-3-methylimidazolium chloride ([Bmim][Cl]) from imidazolium family of ILs, are used in the present study. To address the molecular interactions of ILs with DMSO, densities (ρ), ultrasonic sound velocities (u), and viscosities (η) have been measured over the entire composition range and at four temperatures, 25, 30, 35, and 40 °C, under atmospheric pressure. From these experimental data, the excess molar volume (V(E)), the deviation in isentropic compressibility (Δκs), and the deviation in viscosity (Δη) were calculated and were adequately correlated by using the Redlich-Kister polynomial equation. The measured and predicted data were interpreted on the basis of intermolecular interactions and structural effects between like and unlike molecules upon mixing. The hydrogen-bonding features between ammonium-based ILs and DMSO were analyzed using molecular modeling program by HyperChem 7.

  12. Direct UV-spectroscopic measurement of selected ionic-liquid vapors

    SciTech Connect

    Dai, Sheng; Luo, Huimin; Wang, Congmin; Li, Haoran

    2010-01-01

    The hallmark of ionic liquids lies in their negligible vapor pressure. This ultralow vapor pressure makes it difficult to conduct the direct spectroscopic measurement of ionic-liquid vapors. In fact, there have been no electronic spectroscopic data currently available for ionic-liquid vapors. This deficiency significantly hampers the fundamental understanding of the unique molecular structures of ionic liquids. Herein, the UV absorption spectra of eight ionic liquids, such as 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([Bmim{sup +}] [Tf{sub 2}N{sup -}]) and 1-ethyl-3-methylimidazolium bis(perfluoroethylsulfonyl)imide ([Emim{sup +}][beti{sup -}]) in the vapor phase in a distillation-like environment, were measured through a high-temperature spectroscopic technique to fill this knowledge gap. Two strong absorption peaks of the [Bmim{sup +}][Tf{sub 2}N{sup -}] vapor lie at 202 and 211 nm, slightly different from those of the neat [Bmim{sup +}][Tf{sub 2}N{sup -}] thin film and its solution in water. Based on the quantitative determination of the vapor absorption spectra as a function of temperature, the vaporization enthalpies of these ionic liquids vapors were measured and found to be in good agreement with the corresponding literature values. This in situ method opens up a new avenue to study the nature of ionic-liquid vapors and to determine the vaporization enthalpies of ionic liquids.

  13. Determination of water in room temperature ionic liquids by cathodic stripping voltammetry at a gold electrode.

    PubMed

    Zhao, Chuan; Bond, Alan M; Lu, Xunyu

    2012-03-20

    An electrochemical method based on cathodic stripping voltammetry at a gold electrode has been developed for the determination of water in ionic liquids. The technique has been applied to two aprotic ionic liquids, (1-butyl-3-ethylimidazolium tetrafluoroborate and 1-butyl-3-methylimidazolium hexafluorophosphate), and two protic ionic liquids, (bis(2-hydroxyethyl)ammonium acetate and triethylammonium acetate). When water is present in an ionic liquid, electrooxidation of a gold electrode forms gold oxides. Thus, application of an anodic potential scan or holding the potential of the electrode at a very positive value leads to accumulation of an oxide film. On applying a cathodic potential scan, a sensitive stripping peak is produced as a result of the reduction of gold oxide back to gold. The magnitude of the peak current generated from the stripping process is a function of the water concentration in an ionic liquid. The method requires no addition of reagents and can be used for the sensitive and in situ determination of water present in small volumes of ionic liquids. Importantly, the method allows the determination of water in the carboxylic acid-based ionic liquids, such as acetate-based protic ionic liquids, where the widely used Karl Fischer titration method suffering from an esterification side reaction which generates water as a side product.

  14. Solvation of a Cellulose Microfibril in Imidazolium Acetate Ionic Liquids: Effect of a Cosolvent.

    PubMed

    Velioglu, Sadiye; Yao, Xun; Devémy, Julien; Ahunbay, M Goktug; Tantekin-Ersolmaz, S Birgul; Dequidt, Alain; Costa Gomes, Margarida F; Pádua, Agílio A H

    2014-12-26

    The solvation and the onset of dissolution of a cellulose I(β) microcrystal in ionic liquid media are studied by molecular simulation. Ionic liquids can dissolve large amounts of cellulose, which can later be regenerated from solution, but their high viscosity is an inconvenience. Hydrogen bonding between the anion of the ionic liquid and cellulose is the main aspect determining dissolution. Here we try to elucidate the role of a molecular cosolvent, dimethyl sulfoxide (DMSO), which is an aprotic polar compound, in the system composed of cellulose and the ionic liquid 1-butyl-3-methylimidazolium acetate. We calculated quantities related to specific interactions (mainly hydrogen bonds), conformations, and the structure of local solvation environments, both for a solvated oligomer chain of cellulose and for a model microfibril composed of 36 chains in the I(β) crystal structure. We compare two solvent systems: the pure ionic liquid and a mixed solvent with an equimolar composition in ionic liquid and DMSO. All entities are represented by detailed all-atom, fully flexible force fields. The main conclusions are that DMSO behaves as an "innocent" cosolvent, lowering the viscosity and accelerating mass transport in the system, but without interacting specifically with cellulose or disrupting the interactions between cellulose with the anions of the ionic liquid. An understanding of solvation in mixed solvents composed of ionic liquids and molecular compounds can enable the design of high-performance media for the use of biomass materials.

  15. Salting-out homogenous extraction followed by ionic liquid/ionic liquid liquid-liquid micro-extraction for determination of sulfonamides in blood by high performance liquid chromatography.

    PubMed

    Liu, Zhongling; Yu, Wei; Zhang, Hanqi; Gu, Fanbin; Jin, Xiangqun

    2016-12-01

    Salting-out homogenous extraction followed by ionic liquid/ionic liquid dispersive liquid-liquid micro-extraction system was developed and applied to the extraction of sulfonamides in blood. High-performance liquid chromatography was applied to the determination of the analytes. The blood sample was centrifuged to obtain the serum. After the proteins in the serum were removed in the presence of acetonitrile, ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate, dipotassium hydrogen phosphate, ionic liquid 1-Hexyl-3-methylimidazolium hexafluorophosphate were added into the resulting solution. After the resulting mixture was ultrasonically shaken and centrifuged, the precipitate was separated. The acetonitrile was added in the precipitate and the analytes were extracted into the acetonitrile phase. The parameters affecting the extraction efficiency, such as volume of ionic liquid, amount of dipotassium hydrogen phosphate, volume of dispersant, extraction time and temperature were investigated. The limits of detection of sulfamethizole (STZ), sulfachlorpyridazine (SCP), sulfamethoxazole (SMX) and Sulfisoxazole (SSZ) were 4.78, 3.99, 5.21 and 3.77μgL(-1), respectively. When the present method was applied to the analysis of real blood samples, the recoveries of analytes ranged from 90.0% to 113.0% and relative standard deviations were lower than 7.2%.

  16. Determination of pyrethroid pesticides in tomato using ionic liquid-based dispersive liquid-liquid microextraction.

    PubMed

    Han, Dandan; Tang, Baokun; Row, Kyung Ho

    2014-03-01

    A sensitive determination method was developed for the analysis of pyrethroid pesticide residues in tomato samples using ionic liquid-based dispersive liquid-liquid microextraction. A hydrophobic ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) and acetonitrile were used as the extraction solvent and dispersive solvent, respectively. The following experimental parameters affecting the extraction efficiency were examined: types of extraction solvent and volume of extraction solvent, types of dispersive solvent and volume of dispersive solvent and pH and ion strength of the sample solution. Under the optimum conditions, the extraction recoveries ranged from 83.9 to 96.7%. Moreover, the enrichment factors for esbiothrin, fenpropathrin and cyhalothrin were 42, 48 and 45, respectively. The calibration curves were linear with correlation coefficients ranging from 0.9997 to 0.9999 at concentrations of 0.05-1.5 µg/kg. The relative standard deviation (n = 5) was 1.7-4.5%. The limits of detection for esbiothrin, fenpropathrin and cyhalothrin were 8.1, 9.9 and 14.3 µg/kg, respectively.

  17. A roadmap to uranium ionic liquids: Anti-crystal engineering

    SciTech Connect

    Yaprak, Damla; Spielberg, Eike T.; Bäcker, Tobias; Richter, Mark; Mallick, Bert; Klein, Axel; Mudring, Anja -Verena

    2014-04-15

    In the search for uranium-based ionic liquids, tris(N,N-dialkyldithiocarbamato)uranylates have been synthesized as salts of the 1-butyl-3-methylimidazolium (C4mim) cation. As dithiocarbamate ligands binding to the UO22+ unit, tetra-, penta-, hexa-, and heptamethylenedithiocarbamates, N,N-diethyldithiocarbamate, N-methyl-N-propyldithiocarbamate, N-ethyl-N-propyldithiocarbamate, and N-methyl-N-butyldithiocarbamate have been explored. X-ray single-crystal diffraction allowed unambiguous structural characterization of all compounds except N-methyl-N-butyldithiocarbamate, which is obtained as a glassy material only. In addition, powder X-ray diffraction as well as vibrational and UV/Vis spectroscopy, supported by computational methods, were used to characterize the products. Differential scanning calorimetry was employed to investigate the phase-transition behavior depending on the N,N-dialkyldithiocarbamato ligand with the aim to establish structure–property relationships regarding the ionic liquid formation capability. Compounds with the least symmetric N,N-dialkyldithiocarbamato ligand and hence the least symmetric anions, tris(N-methyl-N-propyldithiocarbamato)uranylate, tris(N-ethyl-N-propyldithiocarbamato)uranylate, and tris(N-methyl-N-butyldithiocarbamato)uranylate, lead to the formation of (room-temperature) ionic liquids, which confirms that low-symmetry ions are indeed suitable to suppress crystallization. As a result, these materials combine low melting points, stable complex formation, and hydrophobicity and are therefore excellent candidates for nuclear fuel purification and recovery.

  18. The solvation structures of cellulose microfibrils in ionic liquids

    SciTech Connect

    Mostofian, Barmak; Smith, Jeremy C; Cheng, Xiaolin

    2011-01-01

    The use of ionic liquids for non-derivatized cellulose dissolution promises an alternative method for the thermochemical pretreatment of biomass that may be more efficient and environmentally acceptable than more conventional techniques in aqueous solution. Here, we performed equilibrium MD simulations of a cellulose microfibril in the ionic liquid 1-butyl-3-methylimidazolium chloride (BmimCl) and compared the solute structure and the solute-solvent interactions at the interface with those from corresponding simulations in water. The results indicate a higher occurrence of solvent-exposed orientations of cellulose surface hydroxymethyl groups in BmimCl than in water. Moreover, spatial and radial distribution functions indicate that hydrophilic surfaces are a preferred site of interaction between cellulose and the ionic liquid. In particular, hydroxymethyl groups on the hydrophilic fiber surface adopt a different conformation from their counterparts oriented towards the fiber s core. Furthermore, the glucose units with these solvent-oriented hydroxymethyls are surrounded by the heterocyclic organic cation in a preferred parallel orientation, suggesting a direct and distinct interaction scheme between cellulose and BmimCl.

  19. A roadmap to uranium ionic liquids: Anti-crystal engineering

    DOE PAGES

    Yaprak, Damla; Spielberg, Eike T.; Bäcker, Tobias; ...

    2014-04-15

    In the search for uranium-based ionic liquids, tris(N,N-dialkyldithiocarbamato)uranylates have been synthesized as salts of the 1-butyl-3-methylimidazolium (C4mim) cation. As dithiocarbamate ligands binding to the UO22+ unit, tetra-, penta-, hexa-, and heptamethylenedithiocarbamates, N,N-diethyldithiocarbamate, N-methyl-N-propyldithiocarbamate, N-ethyl-N-propyldithiocarbamate, and N-methyl-N-butyldithiocarbamate have been explored. X-ray single-crystal diffraction allowed unambiguous structural characterization of all compounds except N-methyl-N-butyldithiocarbamate, which is obtained as a glassy material only. In addition, powder X-ray diffraction as well as vibrational and UV/Vis spectroscopy, supported by computational methods, were used to characterize the products. Differential scanning calorimetry was employed to investigate the phase-transition behavior depending on the N,N-dialkyldithiocarbamato ligand with the aim tomore » establish structure–property relationships regarding the ionic liquid formation capability. Compounds with the least symmetric N,N-dialkyldithiocarbamato ligand and hence the least symmetric anions, tris(N-methyl-N-propyldithiocarbamato)uranylate, tris(N-ethyl-N-propyldithiocarbamato)uranylate, and tris(N-methyl-N-butyldithiocarbamato)uranylate, lead to the formation of (room-temperature) ionic liquids, which confirms that low-symmetry ions are indeed suitable to suppress crystallization. As a result, these materials combine low melting points, stable complex formation, and hydrophobicity and are therefore excellent candidates for nuclear fuel purification and recovery.« less

  20. Determination of luteolin and apigenin in celery using ultrasonic-assisted extraction based on aqueous solution of ionic liquid coupled with HPLC quantification.

    PubMed

    Han, Dandan; Row, Kyung Ho

    2011-12-01

    Ionic liquids are a class of organic salts with melting points equal to or below 100 °C, and their use in sample preparation has shown its promise, for example, in alleviation of environmental pollution and improvement of selectivity and extraction of certain interesting compounds. Optimal conditions were obtained by using 1.0 mol L(-1) 1-butyl-3-methylimidazolium methylsulfate ([Bmim][MS]) aqueous solution at pH 1.0 as the extraction solvent. An ultrasonic power of 200 W was chosen to ensure complete dispersion of [Bmim][MS] into celery in 90 min and the solid:liquid ratio was 1:10. The proposed ultrasonic assistant extraction approach, based on ionic liquid aqueous solution, exhibited satisfactory results, with recovery values ranging from 72.7% to 89.5%. Under optimal conditions, compared with conventional solvent extraction amounts of luteolin and apigenin were more than doubled. Copyright © 2011 Society of Chemical Industry.

  1. Co-electroosmotic capillary electrophoresis of basic proteins with 1-alkyl-3-methylimidazolium tetrafluoroborate ionic liquids as non-covalent coating agents of the fused-silica capillary and additives of the electrolyte solution.

    PubMed

    Corradini, Danilo; Nicoletti, Isabella; Bonn, Günther K

    2009-06-01

    The paper reports the results of a study carried out to evaluate the use of three 1-alkyl-3-methylimidazolium-based ionic liquids as non-covalent coating agents for bare fused-silica capillaries and additives of the electrolyte solutions (BGE) for CE of basic proteins in the co-EOF separation mode. The three ionic liquids are differentiated from each other by the length of the alkyl group on the imidazolium cation, consisting of either an ethyl, butyl or octyl substituent, whereas tetrafluoroborate is the common anionic component of the ionic liquids. Coating the capillary with the ionic liquid resulted in improved peak shape and protein separation, while the EOF was maintained cathodic. This indicates that each ionic liquid is effective at masking the protein interaction sites on the inner surface of the capillary, also when its adsorption onto the capillary wall has not completely neutralized all the negative charges arising from the ionization of the silanol groups and the ionic liquid is not incorporated into the BGE employed for separation. Using the coated capillaries with BGE containing the ionic liquid employed for the coating, at concentration low enough to maintaining the EOF cathodic, both peak shape and protein separation varied to different extents, based on the particular ionic liquid used and its concentration. Fast and efficient separation of the model basic protein mixture in co-electroosmotic CE is obtained with the 1-butyl-3-methylimidazolium tetrafluoroborate coated capillary and 100 mM acetate buffer (pH 4.0) containing 4.4 mM 1-butyl-3-methylimidazolium tetrafluoroborate as the BGE.

  2. New Alkylether-Thiazolium Room-Temperature Ionic Liquid Lubricants: Surface Interactions and Tribological Performance.

    PubMed

    Espinosa, Tulia; Sanes, José; Bermúdez, María-Dolores

    2016-07-20

    The use of newly synthesized alkylether-thiazolium ionic liquids as lubricants is described for the first time. Two ionic liquids composed of a thiazolium cation and a bis(trifluoromethanesulfonyl)amide ([Th][Tf2N]) or dicyanamide ([Th][(NC)2N]) anion have been studied, and their tribological behavior has been compared with that of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide ([Im][Tf2N]) in pin-on-disk tests using sapphire balls against AISI 52100 or AISI 316L steels. All ionic liquids show higher contact angles on AISI 316L steel than on AISI 52100, the lowest values found for ([Im][Tf2N]) on both steel surfaces. AISI 52100 shows similar friction coefficients for all lubricants, and negligible wear rates for the ionic liquids containing the bis(trifluoromethanesulfonyl)amide anion. Immersion tests show no corrosion of AISI 52100 in imidazolium or thiazolium bis(trifluoromethanesulfonyl)amide ionic liquids. AISI 316L shows similar friction coefficients for both bis(trifluoromethanesulfonyl)amide ionic liquids, but the lowest wear rate is obtained for [Th][Tf2N]. An increase in friction coefficient and wear rate is observed for thiazolium dicyanamide. This increase is related to a tribocorrosion process due to decomposition of the thiazolium cation. XPS shows the formation of iron sulfide on the wear track on AISI 316L after lubrication with thiazolium dicyanamide. No tribocorrosion processes take place for the [Tf2N] ionic liquids.

  3. Dissociation of equimolar mixtures of aqueous carboxylic acids in ionic liquids: role of specific interactions.

    PubMed

    Shukla, Shashi Kant; Kumar, Anil

    2015-04-30

    Hammett acidity function observes the effect of protonation/deprotonation on the optical density/absorbance of spectrophotometric indicator. In this work, the Hammett acidity, H0, of equimolar mixtures of aqueous HCOOH, CH3COOH, and CH3CH2COOH was measured in 1-methylimidazolium-, 1-methylpyrrolidinium-, and 1-methylpiperidinium-based protic ionic liquids (PILs) and 1-butyl-3-methylimidazolium-based aprotic ionic liquid (AIL) with formate (HCOO(-)) anion. Higher H0 values were observed for the equimolar mixtures of aqueous carboxylic acids in protic ionic liquids compared with those of the aprotic ionic liquid because of the involvement of the stronger specific interactions between the conjugate acid of ionic liquid and conjugate base of carboxylic acids as suggested by the hard-soft acid base (HSAB) theory. The different H0 values for the equimolar mixtures of aqueous carboxylic acids in protic and aprotic ionic liquids were noted to depend on the activation energy of proton transfer (Ea,H(+)). The higher activation energy of proton transfer was obtained in AIL, indicating lower ability to form specific interactions with solute than that of PILs. Thermodynamic parameters determined by the "indicator overlapping method" further confirmed the involvement of the secondary interactions in the dissociation of carboxylic acids. On the basis of the thermodynamic parameter values, the potential of different ionic liquids in the dissociation of carboxylic acids was observed to depend on the hydrogen bond donor acidity (α) and hydrogen bond acceptor basicity (β), characteristics of specific interactions.

  4. The Importance of Ion Size and Electrode Curvature on Electrical Double Layers in Ionic Liquids

    SciTech Connect

    Feng, Guang; Qiao, Rui; Huang, Jingsong; Dai, Sheng; Sumpter, Bobby G; Meunier, Vincent

    2010-01-01

    Room-temperature ionic liquids (ILs) are an emerging class of electrolytes for supercapacitors. We investigate the effects of ion size and electrode curvature on the electrical double layers (EDLs) in two ILs 1-butyl-3-methylimidazolium chloride [BMIM][Cl] and 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF(6)], using a combination of molecular dynamics (MD) and quantum density functional theory (DFT) simulations. The sizes of the counter-ion and co-ion affect the ion distribution and orientational structure of EDLs. The EDL capacitances near both planar and cylindrical electrodes were found to follow the order: [BMIM][Cl] (near the positive electrode) > [BMIM][PF(6)] (near the positive electrode) {approx} [BMIM][Cl] (near the negative electrode) {approx} [BMIM][PF(6)] (near the negative electrode). The EDL capacitance was also found to increase as the electrode curvature increases. These capacitance data can be fit to the Helmholtz model and the recently proposed exohedral electrical double-cylinder capacitor (xEDCC) model when the EDL thickness is properly parameterized, even though key features of the EDLs in ILs are not accounted for in these models. To remedy the shortcomings of existing models, we propose a 'Multiple Ion Layers with Overscreening' (MILO) model for the EDLs in ILs that takes into account two critical features of such EDLs, i.e., alternating layering of counter-ions and co-ions and charge overscreening. The capacitance computed from the MILO model agrees well with the MD prediction. Although some input parameters of the MILO model must be obtained from MD simulations, the MILO model may provide a new framework for understanding many important aspects of EDLs in ILs (e.g., the variation of EDL capacitance with the electrode potential) that are difficult to interpret using classical EDL models and experiments.

  5. The importance of ion size and electrode curvature on electrical double layers in ionic liquids

    SciTech Connect

    Feng, G.; Qiao, R.; Huang, J; Dai, S.; Sumpter, B. G.; Meunier, V.

    2011-01-01

    Room-temperature ionic liquids (ILs) are an emerging class of electrolytes for supercapacitors. We investigate the effects of ion size and electrode curvature on the electrical double layers (EDLs) in two ILs 1-butyl-3-methylimidazolium chloride [BMIM][Cl] and 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF{sub 6}], using a combination of molecular dynamics (MD) and quantum density functional theory (DFT) simulations. The sizes of the counter-ion and co-ion affect the ion distribution and orientational structure of EDLs. The EDL capacitances near both planar and cylindrical electrodes were found to follow the order: [BMIM][Cl] (near the positive electrode) > [BMIM][PF{sub 6}] (near the positive electrode) ≈ [BMIM][Cl] (near the negative electrode) ≈ [BMIM][PF{sub 6}] (near the negative electrode). The EDL capacitance was also found to increase as the electrode curvature increases. These capacitance data can be fit to the Helmholtz model and the recently proposed exohedral electrical double-cylinder capacitor (xEDCC) model when the EDL thickness is properly parameterized, even though key features of the EDLs in ILs are not accounted for in these models. To remedy the shortcomings of existing models, we propose a “Multiple Ion Layers with Overscreening” (MILO) model for the EDLs in ILs that takes into account two critical features of such EDLs, i.e., alternating layering of counter-ions and co-ions and charge overscreening. The capacitance computed from the MILO model agrees well with the MD prediction. Although some input parameters of the MILO model must be obtained from MD simulations, the MILO model may provide a new framework for understanding many important aspects of EDLs in ILs (e.g., the variation of EDL capacitance with the electrode potential) that are difficult to interpret using classical EDL models and experiments.

  6. Encapsulated Ionic Liquids for CO2 Capture: Using 1-Butyl-methylimidazolium Acetate for Quick and Reversible CO2 Chemical Absorption.

    PubMed

    Moya, Cristian; Alonso-Morales, Noelia; Gilarranz, Miguel A; Rodriguez, Juan J; Palomar, Jose

    2016-12-05

    The potential advantages of applying encapsulated ionic liquid (ENIL) to CO2 capture by chemical absorption with 1-butyl-3-methylimidazolium acetate [bmim][acetate] are evaluated. The [bmim][acetate]-ENIL is a particle material with solid appearance and 70 % w/w in ionic liquid (IL). The performance of this material as CO2 sorbent was evaluated by gravimetric and fixed-bed sorption experiments at different temperatures and CO2 partial pressures. ENIL maintains the favourable thermodynamic properties of the neat IL regarding CO2 absorption. Remarkably, a drastic increase of CO2 sorption rates was achieved using ENIL, related to much higher contact area after discretization. In addition, experiments demonstrate reversibility of the chemical reaction and the efficient ENIL regeneration, mainly hindered by the unfavourable transport properties. The common drawback of ILs as CO2 chemical absorbents (low absorption rate and difficulties in solvent regeneration) are overcome by using ENIL systems.

  7. The Effect of Microporous Polymeric Support Modification on Surface and Gas Transport Properties of Supported Ionic Liquid Membranes

    PubMed Central

    Akhmetshina, Alsu A.; Davletbaeva, Ilsiya M.; Grebenschikova, Ekaterina S.; Sazanova, Tatyana S.; Petukhov, Anton N.; Atlaskin, Artem A.; Razov, Evgeny N.; Zaripov, Ilnaz I.; Martins, Carla F.; Neves, Luísa A.; Vorotyntsev, Ilya V.

    2015-01-01

    Microporous polymers based on anionic macroinitiator and toluene 2,4-diisocyanate were used as a support for 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([emim][Tf2N]) immobilization. The polymeric support was modified by using silica particles associated in oligomeric media, and the influence of the modifier used on the polymeric structure was studied. The supported ionic liquid membranes (SILMs) were tested for He, N2, NH3, H2S, and CO2 gas separation and ideal selectivities were calculated. The high values of ideal selectivity for ammonia-based systems with permanent gases were observed on polymer matrixes immobilized with [bmim][PF6] and [emim][Tf2N]. The modification of SILMs by nanosize silica particles leads to an increase of NH3 separation relatively to CO2 or H2S. PMID:26729177

  8. Impact of regeneration process on the crystalline structure and enzymatic hydrolysis of cellulose obtained from ionic liquid.

    PubMed

    Cao, Xuefei; Peng, Xinwen; Sun, Shaoni; Zhong, Linxin; Wang, Sha; Lu, Fachuang; Sun, Runcang

    2014-10-13

    The present study investigated the impact of regeneration process on the crystalline structure and enzymatic hydrolysis behaviors of microcrystalline cellulose (MCC) regenerated from ionic liquid 1-butyl-3-methylimidazolium chloride. The crystalline structures of these regenerated samples were analyzed by X-ray diffraction. Results suggested that almost amorphous cellulose was obtained by regenerating MCC in acetone (DRC-a), while partial cellulose II structure could be found in these regenerated samples from water and ethanol. Additionally, the enzymatic hydrolysis behaviors of MCC and its regenerated samples were comparatively studied. Results showed that above 90% of cellulose could be converted into glucose within 4h for DRC-a and regenerated cellulose without drying (WRC-w) as compared to that of MCC (9.7%). Therefore, the regeneration process could significantly influence the crystallinity and digestibility of cellulose.

  9. Morphology-controlled synthesis of nanostructured zinc hydroxide fluoride via a microwave-assisted ionic liquid route

    NASA Astrophysics Data System (ADS)

    Zhang, Songtao; Zheng, Mingbo; Song, Jiakui; Li, Nianwu; Lu, Hongling; Cao, Jieming

    2014-12-01

    Zinc hydroxide fluoride (Zn(OH)F) with multiform morphologies such as flower-like particles, pumpkin-like aggregates, and hollow orange-like aggregates are prepared by a microwave-assisted ionic liquid method. During synthesis, microwave irradiation accelerates the reaction rate and shortens the reaction time. 1-Butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]) or 1-2-hydroxylethyl-3-methylimidazolium tetrafluoroborate ([C2OHmim][BF4]) is used as both reactant and template. Experimental results indicate that the morphology evolution of Zn(OH)F is mainly controlled by the concentration of zinc acetate solution. A possible mechanism underlying the formation of nanostructured Zn(OH)F with diverse morphologies is proposed. Furthermore, nanoporous ZnO is obtained by the thermal decomposition of as-prepared Zn(OH)F in air, and the morphology is well retained.

  10. Temperature effects on the capacitance of an imidazolium-based ionic liquid on a graphite electrode: a molecular dynamics simulation.

    PubMed

    Liu, Xiaohong; Han, Yining; Yan, Tianying

    2014-08-25

    Temperature-dependent electric double layer (EDL) and differential capacitance-potential (C(d)-U) curves of the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM(+)/PF6(-)) were studied on a graphite electrode by molecular dynamics simulations. It was found that all C(d)-U curves were asymmetric camel-shaped with higher C(d) at negative polarization, attributed to the specific adsorption of BMIM(+). In addition, the maxima of Cd at the negative polarization decrease monotonically with temperature due to the thicker EDL, whereas at the positive polarization they gradually increase from 450 to 550 K and decrease at 600 K. Such temperature effects at positive polarization may be understood in terms of the competition between two aspects: the weakening specific adsorption of BMIM(+) allows more effective screening to the positive charge and overall increasing EDL thickness. Although the former dominates from 450 to 550 K, the latter becomes dominant at 600 K.

  11. Dynamics of solvation and rotational relaxation of Coumarin 153 in ionic liquid confined nanometer-sized microemulsions.

    PubMed

    Chakrabarty, Debdeep; Seth, Debabrata; Chakraborty, Anjan; Sarkar, Nilmoni

    2005-03-31

    The effects of confinement of the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate on solvation dynamics and rotational relaxation of Coumarin 153 (C-153) in Triton X-100/cyclohexane microemulsions have been explored using steady-state and picosecond time-resolved emission spectroscopy. The steady-state and rotational relaxation data indicate that C-153 molecules are incorporated in the core of the microemulsions. The average rotational relaxation time increases with increase in w ([bmim][BF(4)]/[TX-100]) values. The solvent relaxation in the core of the microemulsion occurs on two different time scales and is almost insensitive to the increase in w values. The solvent relaxation is retarded in the pool of the microemulsions compared to the neat solvent. Though, the retardation is very small compared to several-fold retardation of the solvation time of the conventional solvent inside the pool of the microemulsions.

  12. Ionic liquid-based single drop microextraction of ultra-trace copper in food and water samples before spectrophotometric determination

    NASA Astrophysics Data System (ADS)

    Wen, Xiaodong; Deng, Qingwen; Guo, Jie

    2011-09-01

    In this work, room temperature ionic liquid (RTIL) 1-butyl-3-methylimidazolium hexafluorophosphate ([C 4mim]PF 6) was used as extractant in single drop microextraction (SDME). The traditionally volatile organic extractants were substituted by this green reagent, which changed SDME preconcentration into environmentally friendly method, relatively. After this pretreatment, ultra-trace copper in water and food samples could be accurately detected by spectrophotometer. This study was focused on the improvement of the analytical performance of spectrophotometric determination, expanding its applications. The influence factors relevant to IL-SDME, such as absorption spectra of complex, drop volume of RTIL, stirring rate and time, concentration of chelating agent, pH, and salt effect were studied systematically. Under the optimal conditions, the limit of detection (LOD) was 0.15 μg L -1 with an enhancement factor (EF) of 33. The proposed method was green, simple, rapid, sensitive, and cost-efficient.

  13. Exploration of complexes of 18-crown-6 with three similarly substituted imidazolium, pyridinium and pyrrolidinium ionic liquids

    NASA Astrophysics Data System (ADS)

    Saha, Subhadeep; Roy, Mahendra Nath

    2017-09-01

    Supramolecular host-guest complexation with excellent comparison among three similarly substituted ionic liquids, namely, 1-butyl-3-methylimidazolium chloride, 1-butyl-4-methylpyridinium chloride and 1-butyl-1-methylpyrrolidinium chloride have been investigated with 18-crown-6 in acetonitrile medium by conductivity in a range of temperature to elucidate the stoichiometry of the complexes. The programmed mathematical study with the help of conductivity data provides association constants for the complexes, by which the thermodynamic properties have been evaluated for improved understanding about complexation. The molecular interactions have been explained and critically discussed with the help of FT-IR and 1H NMR spectroscopic studies, which illustrate H-bond and ion-dipolar attractions primarily exist in complexation.

  14. The Effect of Microporous Polymeric Support Modification on Surface and Gas Transport Properties of Supported Ionic Liquid Membranes.

    PubMed

    Akhmetshina, Alsu A; Davletbaeva, Ilsiya M; Grebenschikova, Ekaterina S; Sazanova, Tatyana S; Petukhov, Anton N; Atlaskin, Artem A; Razov, Evgeny N; Zaripov, Ilnaz I; Martins, Carla F; Neves, Luísa A; Vorotyntsev, Ilya V

    2015-12-30

    Microporous polymers based on anionic macroinitiator and toluene 2,4-diisocyanate were used as a support for 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF₆]) and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([emim][Tf₂N]) immobilization. The polymeric support was modified by using silica particles associated in oligomeric media, and the influence of the modifier used on the polymeric structure was studied. The supported ionic liquid membranes (SILMs) were tested for He, N₂, NH₃, H₂S, and CO₂ gas separation and ideal selectivities were calculated. The high values of ideal selectivity for ammonia-based systems with permanent gases were observed on polymer matrixes immobilized with [bmim][PF₆] and [emim][Tf₂N]. The modification of SILMs by nanosize silica particles leads to an increase of NH₃ separation relatively to CO₂ or H₂S.

  15. Mutual and thermal diffusivity of binary mixtures of the ionic liquids [BMIM][C(CN)3] and [BMIM][B(CN)4] with dissolved CO2 by dynamic light scattering.

    PubMed

    Rausch, Michael H; Heller, Andreas; Herbst, Jonas; Koller, Thomas M; Bahlmann, Matthias; Schulz, Peter S; Wasserscheid, Peter; Fröba, Andreas P

    2014-05-01

    Ionic liquids (ILs) are promising solvents for gas separation processes such as carbon dioxide (CO2) capture from flue gases. For the design of corresponding processes and apparatus, thermophysical properties of ILs containing dissolved gases are required. In the present study, it is demonstrated that with a single optical setup, mutual and thermal diffusivities as well as refractive indices can be measured quasi-simultaneously for such mixtures. Dynamic light scattering (DLS) from bulk fluids was applied to determine mutual and thermal diffusivities for mixtures of 1-butyl-3-methylimidazolium tricyanomethanide ([BMIM][C(CN)3]) or 1-butyl-3-methylimidazolium tetracyanoborate ([BMIM][B(CN)4]) with dissolved CO2 at temperatures from 303.15 to 333.15 K and pressures between 2 and 26 bar in macroscopic thermodynamic equilibrium. Good agreement with literature data and only slight differences between the diffusivities measured for the two systems at the same temperature and comparable mole fractions of CO2 were found. Increasing mutual diffusivities with increasing mole fractions of CO2 are consistent with decreasing viscosities reported for other IL-CO2 mixtures in the literature and can be attributed to weakening of molecular interactions by the dissolved gas. For the conditions studied, no dependence of the thermal diffusivity on the temperature or the mole fraction of CO2 could be found.

  16. Probing the interactions between ionic liquids and water: experimental and quantum chemical approach.

    PubMed

    Khan, Imran; Kurnia, Kiki A; Mutelet, Fabrice; Pinho, Simão P; Coutinho, João A P

    2014-02-20

    For an adequate choice or design of ionic liquids, the knowledge of their interaction with other solutes and solvents is an essential feature for predicting the reactivity and selectivity of systems involving these compounds. In this work, the activity coefficient of water in several imidazolium-based ionic liquids with the common cation 1-butyl-3-methylimidazolium was measured at 298.2 K. To contribute to a deeper insight into the interaction between ionic liquids and water, COSMO-RS was used to predict the activity coefficient of water in the studied ionic liquids along with the excess enthalpies. The results showed good agreement between experimental and predicted activity coefficient of water in ionic liquids and that the interaction of water and ionic liquids was strongly influenced by the hydrogen bonding of the anion with water. Accordingly, the intensity of interaction of the anions with water can be ranked as the following: [CF3SO3](-) < [SCN](-) < [TFA](-) < Br(-) < [TOS](-) < Cl(-) < [CH3SO3](-) [DMP](-) < [Ac](-). In addition, fluorination and aromatization of anions are shown to reduce their interaction with water. The effect of temperature on the activity coefficient of water at infinite dilution was measured by inverse gas chromatography and predicted by COSMO-RS. Further analysis based on COSMO-RS provided information on the nature of hydrogen bonding between water and anion as well as the possibility of anion-water complex formation.

  17. Speciation of rare-earth metal complexes in ionic liquids: a multiple-technique approach.

    PubMed

    Nockemann, Peter; Thijs, Ben; Lunstroot, Kyra; Parac-Vogt, Tatjana N; Görller-Walrand, Christiane; Binnemans, Koen; Van Hecke, Kristof; Van Meervelt, Luc; Nikitenko, Sergey; Daniels, John; Hennig, Christoph; Van Deun, Rik

    2009-01-01

    The dissolution process of metal complexes in ionic liquids was investigated by a multiple-technique approach to reveal the solvate species of the metal in solution. The task-specific ionic liquid betainium bis(trifluoromethylsulfonyl)imide ([Hbet][Tf(2)N]) is able to dissolve stoichiometric amounts of the oxides of the rare-earth elements. The crystal structures of the compounds [Eu(2)(bet)(8)(H(2)O)(4)][Tf(2)N](6), [Eu(2)(bet)(8)(H(2)O)(2)][Tf(2)N](6) x 2 H(2)O, and [Y(2)(bet)(6)(H(2)O)(4)][Tf(2)N](6) were found to consist of dimers. These rare-earth complexes are well soluble in the ionic liquids [Hbet][Tf(2)N] and [C(4)mim][Tf(2)N] (C(4)mim = 1-butyl-3-methylimidazolium). The speciation of the metal complexes after dissolution in these ionic liquids was investigated by luminescence spectroscopy, (1)H, (13)C, and (89)Y NMR spectroscopy, and by the synchrotron techniques EXAFS (extended X-ray absorption fine structure) and HEXS (high-energy X-ray scattering). The combination of these complementary analytical techniques reveals that the cationic dimers decompose into monomers after dissolution of the complexes in the ionic liquids. Deeper insight into the solution processes of metal compounds is desirable for applications of ionic liquids in the field of electrochemistry, catalysis, and materials chemistry.

  18. Interactions of Ionic Liquids with Uranium and its Bioreduction

    SciTech Connect

    Zhang, C.; Francis, A.

    2012-09-18

    We investigated the influence of ionic liquids (ILs) 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM]{sup +}[PF{sub 6}]{sup -}, N-ethylpyridinium trifluoroacetate [EtPy]{sup +}[CF{sub 3}COO]{sup -} and N-ethylpyridinium tetrafluoroborate [Et-Py]{sup +}[BF{sub 4}]{sup -} on uranium reduction by Clostridium sp. under anaerobic conditions. Potentiometric titration, UV-vis spectrophotometry, LC-MS and EXAFS analyses showed monodentate complexation between uranyl and BF{sub 4}{sup -} PF{sub 6}{sup -}; and bidentate complexation with CF{sub 3}COO{sup -}. Ionic liquids affected the growth of Clostridium sp. as evidenced by decrease in optical density, changes in pH, gas production, and the extent of U(VI) reduction and precipitation of U(IV) from solution. Reduction of U(VI) to U(IV) was observed in the presence of [EtPy][BF{sub 4}] and [BMIM][PF{sub 6}] but not with [EtPy][CF{sub 3}COO].

  19. Ionic liquid biodegradability depends on specific wastewater microbial consortia.

    PubMed

    Docherty, Kathryn M; Aiello, Steven W; Buehler, Barbara K; Jones, Stuart E; Szymczyna, Blair R; Walker, Katherine A

    2015-10-01

    Complete biodegradation of a newly-synthesized chemical in a wastewater treatment plant (WWTP) eliminates the potential for novel environmental pollutants. However, differences within- and between-WWTP microbial communities may alter expectations for biodegradation. WWTP communities can also serve as a source of unique consortia that, when enriched, can metabolize chemicals that tend to resist degradation, but are otherwise promising green alternatives. We tested the biodegradability of three ionic liquids (ILs): 1-octyl-3-methylpyridinium bromide (OMP), 1-butyl-3-methylpyridinium bromide (BMP) and 1-butyl-3-methylimidazolium chloride (BMIM). We performed tests using communities from two WWTPs at three time points. Site-specific and temporal variation both influenced community composition, which impacted the success of OMP biodegradability. Neither BMP nor BMIM degraded in any test, suggesting that these ILs are unlikely to be removed by traditional treatment. Following standard biodegradation assays, we enriched for three consortia that were capable of quickly degrading OMP, BMP and BMIM. Our results indicate WWTPs are not functionally redundant with regard to biodegradation of specific ionic liquids. However, consortia can be enriched to degrade chemicals that fail biodegradability assays. This information can be used to prepare pre-treatment procedures and prevent environmental release of novel pollutants.

  20. Laser desorption from a room temperature ionic liquid

    NASA Astrophysics Data System (ADS)

    Harris, Peter Ronald

    We report laser desorption from a Room Temperature Ionic Liquid (RTIL) as a novel source for time of flight mass spectrometry. We use the 2nd harmonic of an Nd:YAG laser to deposit intensities of 1-50 MW/cm2 via backside illumination onto our RTIL desorption sample. A microstructured metal grid situated on top of a glass microscope slide coated with RTIL serves as our desorption sample. The RTIL we use, 1-Butyl, 3-Methylimidazolium Hexafluorophosphate, remains liquid at pressures below 10-8 torr. The use of liquid desorption sample allows for improved surface conditions, homogeneity and sample life as compared to Matrix Assisted Laser Desorption Ionization (MALDI) techniques. Our desorption technique is also unique as it allows the study of both multiphoton and acoustic desorption processes within the same time of flight spectra. Our technique yields intrinsically high resolution, low noise data. We observe differences between ion species in their preference for desorption by a particular desorption method. Specifically, we observe desorption solely by acoustic means of an entire RTIL molecule adducted with an RTIL cation. Finally, we report the applicability of this technique for the desorption of biomolecules.

  1. Hydrolysis of microcrystalline cellulose using functionalized Bronsted acidic ionic liquids - A comparative study.

    PubMed

    Parveen, Firdaus; Patra, Tanmoy; Upadhyayula, Sreedevi

    2016-01-01

    Cellulose conversion to platform chemicals is required to meet the demands of increasing population and modernization of the world. Hydrolysis of microcrystalline cellulose was studied with SO3H, COOH and OH functionalized imidazole based ionic liquid using 1-butyl-3-methylimidazolium chloride [BMIM]Cl as a solvent. The influence of temperature, time, acidity of ionic liquids and catalyst loading was studied on hydrolysis reaction. The maximum %TRS yield 85%, was obtained at 100°C and 90min with 0.2g of SO3H functionalized ionic liquid. UV-vis spectroscopy using 4-nitro aniline as an indicator was performed to find out the Hammett function of ionic liquid and acidity trends are as follows: SO3H>COOH>OH. Density functional theory (DFT) calculations were performed to optimize the ionic liquid and their conjugate bases at B3LYP 6-311G++ (d, p) level using Gaussian 09 program. Theoretical findings are in agreement with the experimental results.

  2. Effect of morphology of mesoporous silica on characterization of protic ionic liquid-based composite membranes

    NASA Astrophysics Data System (ADS)

    Ye, Yun-Sheng; Liang, Gao-Wei; Chen, Bo-Han; Shen, Wei-Chung; Tseng, Chi-Yung; Cheng, Ming-Yao; Rick, John; Huang, Yao-Jheng; Chang, Feng-Chih; Hwang, Bing-Joe

    Effects caused by the morphology of mesoporous silica on the characterization of protic ionic liquid-based composite membranes for anhydrous proton exchange membrane applications are investigated. Two types of SBA15 materials with platelet and fiberlike morphologies are synthesized and incorporated into a mixture of polymerizable monomers together with an ionic liquid (IL) [1-butyl-3-methylimidazolium bis(trifluoromethane sulfone)imide (BMIm-TFSI)] to form new conducting membranes using an in situ photo crosslinking process. Incorporation of a defined amount of fiber-shaped SBA 15 and platelet 15 significantly increases the ionic conductivity to between two and three times that of a plain poly(methyl methacrylate) (PMMA)/IL membrane (2.3 mS cm -1) at 160 °C. The protic ionic liquid (PIL) retention ability of the membranes is increased by the capillary forces introduced by the mesoporous silica materials, while ionic conductivity loss after leaching test is retarded. The highest ionic conductivity (5.3 mS cm -1) is obtained by incorporating 5 wt% of P-SBA 15 in the membrane to about six times that of plain PMMA/IL membrane (0.9 mS cm -1) at 160 °C after leaching test.

  3. Noncovalent approach to one-dimensional ion conductors: enhancement of ionic conductivities in nanostructured columnar liquid crystals.

    PubMed

    Shimura, Harutoki; Yoshio, Masafumi; Hoshino, Koji; Mukai, Tomohiro; Ohno, Hiroyuki; Kato, Takashi

    2008-02-06

    Noncovalent design of new liquid-crystalline (LC) columnar assemblies based on an ionic liquid has shown to be useful to achieve anisotropic high ionic conductivities. An equimolar mixture of an ionic liquid, 1-butyl-3-methylimidazolium bromide, and 3-[3,4,5-tri(octyloxy)benzoyloxy]propane-1,2-diol, which is partially miscible with the ionic liquid, exhibits an LC hexagonal columnar phase from -4 to 63 degrees C. This columnar supramolecular assembly forming the nanostructures shows the one-dimensional (1D) ionic conductivity of 3.9 x 10(-3) S cm(-1) at 50 degrees C along the column, which is more than 700 times higher than that of the corresponding covalent-type columnar ionic liquid, 1-methyl-3-[3,4,5-tri(octyloxy)benzyl]imidazolium bromide, which is 5.3 x 10(-6) S cm(-1) at 50 degrees C. This significant enhancement of the ionic conductivity is attributed to the increase of the mobility of the ionic part.

  4. First-Principles, Physically Motivated Force Field for the Ionic Liquid [BMIM][BF4].

    PubMed

    Choi, Eunsong; McDaniel, Jesse G; Schmidt, J R; Yethiraj, Arun

    2014-08-07

    Molecular simulations play an important role in establishing structure-property relations in complex fluids such as room-temperature ionic liquids. Classical force fields are the starting point when large systems or long times are of interest. These force fields must be not only accurate but also transferable. In this work, we report a physically motivated force field for the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) based on symmetry-adapted perturbation theory. The predictions (from molecular dynamics simulations) of the liquid density, enthalpy of vaporization, diffusion coefficients, viscosity, and conductivity are in excellent agreement with experiment, with no adjustable parameters. The explicit energy decomposition inherent in the force field enables a quantitative analysis of the important physical interactions in these systems. We find that polarization is crucial and there is little evidence of charge transfer. We also argue that the often used procedure of scaling down charges in molecular simulations of ionic liquids is unphysical for [BMIM][BF4]. Because all intermolecular interactions in the force field are parametrized from first-principles, we anticipate good transferability to other ionic liquid systems and physical conditions.

  5. The first molecular level monitoring of carbohydrate conversion to 5-hydroxymethylfurfural in ionic liquids. B2O3--an efficient dual-function metal-free promoter for environmentally benign applications.

    PubMed

    Khokhlova, Elena A; Kachala, Vadim V; Ananikov, Valentine P

    2012-04-01

    The mechanistic nature of the conversion of carbohydrates to the sustainable platform chemical 5-hydroxymethylfurfural (5-HMF) was revealed at the molecular level. A detailed study of the key sugar units involved in the biomass conversion process has shown that the simple dissolution of fructose in the ionic liquid 1-butyl-3-methylimidazolium chloride significantly changes the anomeric composition and favors the formation of the open fructoketose form. A special NMR approach was developed for the determination of molecular structures and monitoring of chemical reactions directly in ionic liquids. The transformation of glucose to 5-HMF has been followed in situ through the detection of intermediate species. A new environmentally benign, easily available, metal-free promoter with a dual functionality (B(2)O(3)) was developed for carbohydrate conversion to 5-HMF.

  6. Fabrication of normally-off AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors by photo-electrochemical gate recess etching in ionic liquid

    NASA Astrophysics Data System (ADS)

    Zhang, Zhili; Qin, Shuangjiao; Fu, Kai; Yu, Guohao; Li, Weiyi; Zhang, Xiaodong; Sun, Shichuang; Song, Liang; Li, Shuiming; Hao, Ronghui; Fan, Yaming; Sun, Qian; Pan, Gebo; Cai, Yong; Zhang, Baoshun

    2016-08-01

    We characterized an ionic liquid (1-butyl-3-methylimidazolium nitrate, C8H15N3O3) as a photo-electrochemical etchant for fabricating normally-off AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors (MIS-HEMTs). Using the ionic liquid, we achieved an etching rate of ˜2.9 nm/min, which is sufficiently low to facilitate good etching control. The normally-off AlGaN/GaN MIS-HEMT was fabricated with an etching time of 6 min, with the 20 nm low-pressure chemical vapor deposition (LPCVD) silicon nitride (Si3N4) gate dielectric exhibiting a threshold voltage shift from -10 to 1.2 V, a maximum drain current of more than 426 mA/mm, and a breakdown voltage of 582 V.

  7. Observation of Charge Inversion of an Ionic Liquid at the Solid Salt-Liquid Interface by Sum Frequency Generation Spectroscopy.

    PubMed

    Peñalber, Chariz Y; Baldelli, Steven

    2012-04-05

    Sum frequency generation (SFG) vibrational spectroscopy of the ionic liquid, 1-butyl-3-methylimidazolium dicyanamide [BMIM][DCA], in contact with two different solid salt surfaces, BaF2(111) single crystal and solid NaCl{100}, are discussed in this Letter. This investigation describes the nature of an ionic liquid-(solid) salt interface using SFG, contributing a new understanding to the molecular-level interactions involved in salts, which are conceptually similar compounds (of purely ionic character) but of different physical properties (liquid versus solid at room temperature). Results show the presence of [BMIM](+) at the NaCl{100} surface and [DCA](-) at the BaF2(111) surface. [BMIM](+) cations adhere closely via Coulombic interactions to the negatively charged NaCl{100} surface, while [DCA](-) anions subsequently have a strong electrostatic affinity to the positively charged BaF2(111) surface. Ions of the ionic liquid adsorb to the solid salt surface to form a Helmholtz-like electric double layer.

  8. Synthesis of Asymmetrical Organic Carbonates using CO2 as a Feedstock in AgCl/Ionic Liquid System at Ambient Conditions.

    PubMed

    Hu, Jiayin; Ma, Jun; Lu, Lu; Qian, Qingli; Zhang, Zhaofu; Xie, Chao; Han, Buxing

    2017-03-22

    Synthesis of asymmetrical organic carbonates from the renewable and inexpensive CO2 is of great importance but also challenging, especially at ambient conditions. Herein, we found that some metal salt/ionic liquid catalyst systems were highly active for the synthesis of asymmetrical organic carbonates from CO2 , propargylic alcohols, and primary alcohols. Especially, the AgCl/1-butyl-3-methylimidazolium acetate ([Bmim][OAc]) system was very efficient for the reactions of a wide range of substrates at room temperature and atmospheric pressure, and the yields of the asymmetrical organic carbonates could approach 100 %. The catalyst system could be reused at least five times without changing its catalytic performance, and could be easily recovered and reused. A detailed study indicated that AgCl and [Bmim][OAc] catalyzed the reactions cooperatively, resulting in unique catalytic performance.

  9. Evaluation of a hydrophilic ionic liquid as a salting-out phase separation agent to a water-tetrahydrofuran homogeneous system for aqueous biphasic extraction separation.

    PubMed

    Hirayama, Naoki; Higo, Takaaki; Imura, Hisanori

    2012-01-01

    The use of a hydrophilic ionic liquid (IL), 1-butyl-3-methylimidazolium chloride (C(4)mimCl), as a salting-out phase separation agent to a water-tetrahydrofuran homogeneous system was studied for possible applications to novel aqueous biphasic extraction separation. The IL showed a salting-out phase-separation ability. Also, differences in the polarity between the formed two phases were smaller than that when using NaCl as a salting-out agent. This result suggested that C(4)mimCl remaining in water-rich phase acts not only as a salting-out agent, but also a component of a mixed-solvent. Possible uses of C(4)mimCl/NaCl mixed salting-out agent system were also discussed.

  10. Development of Ionic Liquid Modified Disposable Graphite Electrodes for Label-Free Electrochemical Detection of DNA Hybridization Related to Microcystis spp.

    PubMed Central

    Sengiz, Ceren; Congur, Gulsah; Erdem, Arzum

    2015-01-01

    In this present study, ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate (IL)) modified pencil graphite electrode (IL-PGEs) was developed for electrochemical monitoring of DNA hybridization related to Microcystis spp. (MYC). The characterization of IL-PGEs was performed using microscopic and electrochemical techniques. DNA hybridization related to MYC was then explored at the surface of IL-PGEs using differential pulse voltammetry (DPV) technique. After the experimental parameters were optimized, the sequence-selective DNA hybridization related to MYC was performed in the case of hybridization between MYC probe and its complementary DNA target, noncomplementary (NC) or mismatched DNA sequence (MM), or and in the presence of mixture of DNA target: NC (1:1) and DNA target: MM (1:1). PMID:26371004

  11. Development of Ionic Liquid Modified Disposable Graphite Electrodes for Label-Free Electrochemical Detection of DNA Hybridization Related to Microcystis spp.

    PubMed

    Sengiz, Ceren; Congur, Gulsah; Erdem, Arzum

    2015-09-09

    In this present study, ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate (IL)) modified pencil graphite electrode (IL-PGEs) was developed for electrochemical monitoring of DNA hybridization related to Microcystis spp. (MYC). The characterization of IL-PGEs was performed using microscopic and electrochemical techniques. DNA hybridization related to MYC was then explored at the surface of IL-PGEs using differential pulse voltammetry (DPV) technique. After the experimental parameters were optimized, the sequence-selective DNA hybridization related to MYC was performed in the case of hybridization between MYC probe and its complementary DNA target, noncomplementary (NC) or mismatched DNA sequence (MM), or and in the presence of mixture of DNA target: NC (1:1) and DNA target: MM (1:1).

  12. TiO2 nanoparticles: low-temperature hydrothermal synthesis in ionic liquids/water and the photocatalytic degradation for o-nitrophenol.

    PubMed

    Dai, Jingtao; He, Ruiyu; Yuan, Yuan; Wang, Wei; Fanga, Dong

    2014-01-01

    The well-crystallized anatase TiO2-IL nanoparticles were synthesized by one-step routes under low-temperature using room temperature ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate as an additional solvent with water. The photocatalytic properties of TiO2 nanoparticles were evaluated by photocatalytic degradation experiments of o-nitrophenol. The TiO2 nanoparticles show a higher photocatalytic activity than the TiO2 with pure water and commercial TiO2 (P25), which may be related to the high crystallinity. The TiO2-IL nanoparticles still hold a high photocatalytic activity after the catalyst was recycled nine times. Chemical oxygen demand removal was achieved under optimum experimental conditions.

  13. The effect of surfactant-assisted ultrasound-ionic liquid pretreatment on the structure and fermentable sugar production of a water hyacinth.

    PubMed

    Chang, Ken-Lin; Han, Ye-Ju; Wang, Xiao-Qin; Chen, Xi-Mei; Leu, Shao-Yuan; Liu, Jing-Yong; Peng, Yen-Ping; Liao, Yu-Ling; Potprommanee, Laddawan

    2017-08-01

    This study investigated the possibility of enhancing the disruption of water hyacinth (WH) in an ultrasound-ionic liquid (US-IL) pretreatment assisted by sodium dodecyl sulfate (SDS). 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) was used to dissolve the WH. The optimum concentration of SDS for the highest production of reducing sugar was also determined. Compared to the US-IL pretreatment, the production of reducing sugars, cellulose conversion and delignification were increased by 72.23%, 58.74% and 21.01%, respectively, upon addition of 0.5% SDS. Moreover, the enhancement of SDS in the US-IL pretreatment was confirmed by the analysis of structural features, which demonstrated that the SDS increased the removal of lignin and decreased the cellulose crystallinity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Sensitive determination of Amaranth in drinks by highly dispersed CNT in graphene oxide "water" with the aid of small amounts of ionic liquid.

    PubMed

    Wang, Meiling; Sun, Yinlu; Yang, Xiongbo; Zhao, Jianwei

    2015-07-15

    Graphene oxide (GO) is a pH-dependent amphiphile. In this paper, it was found that carbon nanotubes (CNTs) can be highly dispersed in graphene oxide "water" with the aid of prototype ionic liquid of 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]). The introduction of [BMIM][PF6] not only can minimize the defects of poor electrical conductivity of GO, but also can improve the dispersibility of CNT in water. Hence, a new composite of CNT/GO-[BMIM][PF6] with high dispersibility and strong conductivity was presented for the first time and employed in the sensitive determination of Amaranth in soft drinks. The detection limit achieved (0.1 nM) is much lower than the guideline values in soft drinks. The ease of preparation, low background current, high sensitivity and stability can create novel avenues and applications for fabricating robust sensors for determination of other azo dyes in foods.

  15. Structural and Dielectric Properties of Ionic Liquid Doped Metal Organic Framework based Polymer Electrolyte Nanocomposites

    NASA Astrophysics Data System (ADS)

    Dutta, Rituraj; Kumar, Ashok

    2016-10-01

    Metal Organic Frameworks (MOFs) are mesoporous materials that can be treated as potential hosts for trapping guest molecules in their pores. Ion conduction and phase behavior dynamics of Ionic Liquids (ILs) can be controlled by tunable interactions of MOFs with the ILs. MOFs incorporated with ionic liquid can be dispersed in the polymers to synthesize polymer electrolyte nanocomposites with high ionic conductivity, electrochemical and thermal stability for applications in energy storage and conversion devices such as rechargeable Li-ion batteries. In the present work we have synthesized Cu-based MOF [Cu3(l,3,5-benzene tricarboxylate)2(H2O)] incorporated with the ionic liquid 1-Butyl-3-methylimidazolium bromide at different weight ratios of MOF and IL. The synthesized MOF-IL composites are dispersed in Poly (ethylene oxide) (PEO). Frequency dependent behavior of permittivity and dielectric loss of the nanocomposites depict the non-Debye dielectric relaxation mechanism. The room temperature Nyquist plots reveal decreasing bulk resistance upto 189 Ω with optimum ionic conductivity of 1.3×10-3S cm-1at maximum doping concentration of IL in the nanocomposite system.

  16. Phase Transitions of Triflate-Based Ionic Liquids under High Pressure.

    PubMed

    Faria, Luiz F O; Ribeiro, Mauro C C

    2015-11-05

    Raman spectroscopy has been used to study phase transitions of ionic liquids based on the triflate anion, [TfO](-), as a function of pressure or temperature. Raman spectra of ionic liquids containing the cations 1-butyl-3-methylimidazolium, [C4C1Im](+), 1-octyl-3-methylimidazolium, [C8C1Im](+), 1-butyl-2,3-dimethylimidazolium, [C4C1C1Im](+), and 1-butyl-1-methylpyrrolidinium, [C4C1Pyr](+), were compared. Vibrational frequencies and binding energy of ionic pairs were calculated by quantum chemistry methods. The ionic liquids [C4C1Im][TfO] and [C4C1Pyr][TfO] crystallize at 1.0 GPa when the pressure is increased in steps of ∼ 0.2 GPa from the atmospheric pressure, whereas [C8C1Im][TfO] and [C4C1C1Im][TfO] do not crystallize up to 2.3 GPa of applied pressure. The low-frequency range of the Raman spectrum of [C4C1Im][TfO] indicates that the system undergoes glass transition, rather than crystallization, when the pressure applied on the liquid has been increased above 2.0 GPa in a single step. Strong hysteresis of spectral features (frequency shift and bandwidth) of the high-pressure crystalline phase when the pressure was released stepwise back to the atmospheric pressure has been found .

  17. Effect of unsaturation on the absorption of ethane and ethylene in imidazolium-based ionic liquids.

    PubMed

    Moura, Leila; Mishra, Manas; Bernales, Varinia; Fuentealba, Patricio; Padua, Agilio A H; Santini, Catherine C; Costa Gomes, Margarida F

    2013-06-20

    The influence of the presence of imidazolium side chain unsaturation on the solubility of ethane and ethylene was studied in three ionic liquids: 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide-saturated alkyl side-chain in the cation; 1-methyl-3-(buten-3-yl)imidazolium bis(trifluorosulfonyl)imide-double bond in the side-chain of the cation; and 1-methyl-3-benzylimidazolium bis(trifluorosulfonyl)imide-benzyl group in the side-chain of the cation. The solubility of both gases decreases when the side-chain of the cations is functionalized with an unsaturated group. This can be explained by a less favorable enthalpy of solvation. The difference of solubility between ethane and ethylene can be explained from a balance of enthalpic and entropic factors: for the ionic liquid with the saturated alkyl side-chain and the benzyl-substituted side-chain, it is the favorable entropy of solvation that explains the larger ethylene solubility, whereas in the case of the saturated side-chain, it is the more favorable enthalpy of solvation. Molecular simulation allowed the identification of the mechanisms of solvation and the preferential solvation sites for each gas in the different ionic liquids. Simulations have shown that the entropy of solvation is more favorable when the presence of the gas weakens the cation-anion interactions or when the gas can be solvated near different sites of the ionic liquid.

  18. [Effects of imidazolium chloride ionic liquids on the acute toxicity and weight of earthworm].

    PubMed

    Huang, Ruo-Nan; Fan, Jun-Jie; Tu, Hong-Zhi; Tang, Ling-Yan; Liu, Hui-Jun; Xu, Dong-Mei

    2013-04-01

    Standard contact filter paper test of OECD and artificial soil test were used to study the acute lethal effect of three imidazolium chloride ionic liquids, 1-butyl- 3-methylimidazolium chloride ([Bmim] Cl), 1-hexyl- 3-methylimidazolium chloride ([Hmim] Cl), and 1-octyl- 3-methylimidazolium chloride ([Omim] Cl) on earthworm (Eisenia fetida), and the weight of the earthworms was measured after subtle exposure. The 24 h-LC50 values of [Bmim] Cl, [Hmim] Cl and [Omim] Cl using the contact filter paper method were 109.60, 50.38 and 7.94 microg x cm(-2), respectively. The 48 h-LC50 values were 98.52, 39.14 and 3.61 microg x cm(-2), respectively. Using the artificial soil method, the 7 d-LC50 values of [Bmim] Cl, [Hmim] Cl and [Omim] Cl were 447.78, 245.56 and 180.51 mg x kg(-1), respectively, and the 14 d-LC50 values were 288.42, 179.75, 150.35 mg x kg(-1), respectively. There were differences in poisoning symptoms of the three ionic liquids on earthworms. The growth of Eisenia fetida was inhibited and declined with increasing ionic liquid concentration. The toxicity of ionic liquids on Eisenia fetida increased with the length of carbon chain.

  19. Structure and mechanisms underlying ion transport in ternary polymer electrolytes containing ionic liquids

    NASA Astrophysics Data System (ADS)

    Mogurampelly, Santosh; Ganesan, Venkat

    2017-02-01

    We use all atom molecular dynamics simulations to investigate the influence of 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6) ionic liquid on the structure and transport properties of poly(ethylene oxide) (PEO) polymer electrolytes doped with LiPF6 salt. We observe enhanced diffusivities of the Li+, PF6-, and BMIM+ ions with increasing loading of the ionic liquid. Interplay between the different ion-ion and ion-polymer interactions is seen to lead to a destabilization of the Li-PF6 coordination and increase in the strength of association between the Li+ cations and the polymer backbone. As a consequence, the polymer segmental relaxation times are shown to be only moderately affected by the addition of ionic liquids. The ionic-liquid induced changes in the mobilities of Li+ ions are seen to be correlated to polymer segmental relaxation times. However, the mobilities of BMIM+ ions are seen to be more strongly correlated to the BMIM-PF6 ion-pair relaxation times.

  20. Solvent effects on the polar network of ionic liquid solutions

    NASA Astrophysics Data System (ADS)

    Bernardes, Carlos E. S.; Shimizu, Karina; Canongia Lopes, José N.

    2015-05-01

    Molecular dynamics simulations were used to probe mixtures of ionic liquids (ILs) with common molecular solvents. Four types of systems were considered: (i) 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide plus benzene, hexafluorobenzene or 1,2-difluorobenzene mixtures; (ii) choline-based ILs plus ether mixtures (iii) choline-based ILs plus n-alkanol mixtures; and (iv) 1-butyl-3-methylimidazolium nitrate and 1-ethyl-3-methylimidazolium ethyl sulfate aqueous mixtures. The results produced a wealth of structural and aggregation information that highlight the resilience of the polar network of the ILs (formed by clusters of alternating ions and counter-ions) to the addition of different types of molecular solvent. The analysis of the MD data also shows that the intricate balance between different types of interaction (electrostatic, van der Waals, H-bond-like) between the different species present in the mixtures has a profound effect on the morphology of the mixtures at a mesoscopic scale. In the case of the IL aqueous solutions, the present results suggest an alternative interpretation for very recently published x-ray and neutron diffraction data on similar systems.

  1. Thinning of reverse osmosis membranes by ionic liquids

    NASA Astrophysics Data System (ADS)

    Meng, Hong; Gong, Beibei; Geng, Tao; Li, Chunxi

    2014-02-01

    In this study, ionic liquids (ILs) were used to thin out the dense layer and, in turn, tune the surface properties and separation performance of commercial aromatic polyamide reverse osmosis membranes. It was observed that the structure of the ILs and dipping time had a strong impact on the dense layer thickness and morphology. This can be understood in terms of the dissolubility and interaction force between ILs and the organic membrane surface, such as hydrogen bonding and π-π interactions. Among the ILs synthesized, 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) showed the most promising thinning effects. It was observed that the thickness of the dense layer on the surface decreased from 127 to 67 nm after dipping treatment with [BMIM]Cl for 24 h. The water flux was enhanced by 20% at the expense of a slight decline of salt rejection. AFM, contact angle and zeta potential analyses suggest that the surface hydrophilicity and electronegativity increased, while the roughness decreased, which improved the anti-fouling properties.

  2. Molecular origin of high free energy barriers for alkali metal ion transfer through ionic liquid-graphene electrode interfaces.

    PubMed

    Ivaništšev, Vladislav; Méndez-Morales, Trinidad; Lynden-Bell, Ruth M; Cabeza, Oscar; Gallego, Luis J; Varela, Luis M; Fedorov, Maxim V

    2016-01-14

    In this work we study mechanisms of solvent-mediated ion interactions with charged surfaces in ionic liquids by molecular dynamics simulations, in an attempt to reveal the main trends that determine ion-electrode interactions in ionic liquids. We compare the interfacial behaviour of Li(+) and K(+) at a charged graphene sheet in a room temperature ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate, and its mixtures with lithium and potassium tetrafluoroborate salts. Our results show that there are dense interfacial solvation structures in these electrolytes that lead to the formation of high free energy barriers for these alkali metal cations between the bulk and direct contact with the negatively charged surface. We show that the stronger solvation of Li(+) in the ionic liquid leads to the formation of significantly higher interfacial free energy barriers for Li(+) than for K(+). The high free energy barriers observed in our simulations can explain the generally high interfacial resistance in electrochemical storage devices that use ionic liquid-based electrolytes. Overcoming these barriers is the rate-limiting step in the interfacial transport of alkali metal ions and, hence, appears to be a major drawback for a generalised application of ionic liquids in electrochemistry. Some plausible strategies for future theoretical and experimental work for tuning them are suggested.

  3. Organo-niobate Ionic Liquids: Synthesis, Characterization and Application as Acid Catalyst in Pechmann Reactions

    PubMed Central

    Soares, Valerio C. D.; Alves, Melquizedeque B.; Souza, Ernesto R.; Pinto, Ivana O.; Rubim, Joel C.; Andrade, Carlos Kleber Z.; Suarez, Paulo A. Z.

    2007-01-01

    The combinations of 1-butyl-3-methylimidazolium chloride with NbCl5 yielded ionic mixtures with different melting point temperatures and acidity depending on the niobium molar fraction. The mixtures were characterized by thermal (DSC) and spectroscopic (FT-IR and 1H NMR) analysis. The Pechmann reactions of different phenols with ethylacetoacetate, producing coumarins, was used as model to evaluate the catalytic behavior of these mixtures as acid Lewis catalyst. These reactions were carried out using acidic mixtures of 60 mol%.

  4. Ionic liquid-based dispersive liquid-liquid microextraction for sensitive determination of aromatic amines in environmental water.

    PubMed

    Han, Dandan; Yan, Hongyuan; Row, Kyung H

    2011-05-01

    Ionic liquid-based dispersive liquid-liquid microextraction was developed for the extraction and preconcentration of aromatic amine from environmental water. A suitable mixture of extraction solvent (100 μL, 1-butyl-3-methylimidazolium hexafluorophoshate) and dispersive solvent (750 μL, methanol) were injected into the aqueous samples (10.00 mL), forming a cloudy solution. After centrifuging, enriched analytes in the sediment phase were determined by HPLC-UV. The effect of various factors, such as the extraction and dispersive solvent, sample pH, extraction time and salt effect were investigated. Under optimum conditions, enrichment factors for 2-anilinoethanol, o-chloroaniline and 4-bromo-N,N-dimethylaniline were above 50 and the limits of detection (LODs) were 0.023, 0.015 and 0.026 ng/mL, respectively. Their linear ranges were 0.8-400 ng/mL for 2-anilinoethanol, 0.5-200 ng/mL for o-chloroaniline and 0.4-200 ng/mL for 4-bromo-N,N-dimethylaniline, respectively. Relative standard deviations (RSDs) were below 5.0%. The relative recoveries from samples of environmental water were in the range of 82.0-94.0%. Compared with other methods, dispersive liquid-liquid microextraction is simple, rapid, sensitive and economical.

  5. On the interfacial behavior of ionic liquids: surface tensions and contact angles.

    PubMed

    Restolho, José; Mata, José L; Saramago, Benilde

    2009-12-01

    In this work the liquid/vapour and the solid/liquid interfaces of a series of ionic liquids: 1-ethyl-3-methylpyridinium ethyl sulfate, [EMPy][EtSO4], 1-ethyl-3-methylimidazolium ethyl sulfate, [EMIM][EtSO4], 1-ethanol-3-methylimidazolium tetrafluoroborate, [C2OHMIM][BF4], 1-butyl-3-methylimidazolium tetrafluoroborate, [BMIM][BF4], and 1-octyl-3-methylimidazolium tetrafluoroborate, [OMIM][BF4], were investigated. The surface tension was measured in a wide temperature range, (298-453) K. The contact angles were determined on substrates of different polarities. Both on the polar (glass) and the non-polar substrates ((poly-(tetrafluoroethylene) and poly-(ethylene)), the liquids with maximum and minimum surface tensions lead, respectively, to the highest and the lowest contact angles. The dispersive, gamma(L)(d), and non-dispersive, gamma(L)(nd), components of the liquid surface tension, gamma(L), were calculated from the contact angles on the non-polar substrates using the Fowkes approach. The polarity fraction, gamma(L)(nd)/gamma(L), was compared with the polarity parameter, k, obtained from the fitting of the surface tension vs. temperature data to the Eötvös equation. Good agreement was found for the extreme cases: [OMIM][BF4] exhibits the lowest polarity and [BMIM][BF4], the highest. When compared with the polarity fractions of standard liquids considered as "polar" liquids, the ionic liquids studied may be considered as moderately polar.

  6. Soft microgripping using ionic liquids for high temperature and vacuum applications

    NASA Astrophysics Data System (ADS)

    Amin, Abdullah Al; Jagtiani, Ashish; Vasudev, Abhay; Hu, Jun; Zhe, Jiang

    2011-12-01

    Aqueous droplet-based micro-gripper has been used for micro-assembly. However they cannot be used for high temperature and vacuum applications. Ionic liquids, organic salts that have a lower melting point temperature, appear suitable for droplet-based micro-gripping application in high temperature and vacuum environments because of their nonvolatility and thermal stability. In this paper, we demonstrated the use of ionic liquid as the operating liquid for micro-gripping applications in high temperatures (up to 110 °C) and vacuum (up to 24 inch Hg) environments. Electrowetting was utilized to dynamically change the contact angle of a 1-butyl-3-methylimidazolium hexafluorophosphate (BmimPF6) liquid bridge to control the capillary lifting forces. The lifting force generated by the liquid bridge was experimentally characterized. The range of capillary lifting forces can be adjusted by changing the liquid bridge height and droplet volume to pick up and release objects with different weights. The dynamic response of the BmimPF6 liquid bridge was also characterized.

  7. Novel microemulsions: ionic liquid-in-ionic liquid.

    PubMed

    Cheng, Siqing; Zhang, Jianling; Zhang, Zhaofu; Han, Buxing

    2007-06-28

    The hydrophobic IL 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF(6)]) can be dispersed in hydrophilic IL propylammonium formate (PAF) with the aid of surfactant AOT, and [bmim][PF(6)]-in-PAF microemulsions are formed.

  8. The effects of high concentrations of ionic liquid on GB1 protein structure and dynamics probed by high-resolution magic-angle-spinning NMR spectroscopy.

    PubMed

    Warner, Lisa; Gjersing, Erica; Follett, Shelby E; Elliott, K Wade; Dzyuba, Sergei V; Varga, Krisztina

    2016-12-01

    Ionic liquids have great potential in biological applications and biocatalysis, as some ionic liquids can stabilize proteins and enhance enzyme activity, while others have the opposite effect. However, on the molecular level, probing ionic liquid interactions with proteins, especially in solutions containing high concentration of ionic liquids, has been challenging. In the present work the (13)C, (15)N-enriched GB1 model protein was used to demonstrate applicability of high-resolution magic-angle-spinning (HR-MAS) NMR spectroscopy to investigate ionic liquid - protein interactions. Effect of an ionic liquid (1-butyl-3-methylimidazolium bromide, [C4-mim]Br) on GB1was studied over a wide range of the ionic liquid concentrations (0.6 to 3.5 M, which corresponds to 10%-60% v/v). Interactions between GB1 and [C4-mim]Br were observed from changes in the chemical shifts of the protein backbone as well as the changes in (15)N ps-ns dynamics and rotational correlation times. Site-specific interactions between the protein and [C4-mim]Br were assigned using 3D methods under HR-MAS conditions. Thus, HR-MAS NMR is a viable tool that could aid in elucidation of the molecular mechanism of ionic liquid - protein interactions.

  9. Application and recovery of ionic liquids in the preparative separation of four flavonoids from Rhodiola rosea by on-line three-dimensional liquid chromatography.

    PubMed

    Ma, Shufeng; Hu, Liming; Ma, Chaoyang; Lv, Wenping; Wang, Hongxin

    2014-09-01

    A novel on-line three-dimensional liquid chromatography method was developed to separate four main flavonoids from Rhodiola rosea. Ethyl acetate/0.5 mol/L ionic liquid 1-butyl-3-methylimidazolium chloride aqueous solution was selected as the solvent system. In the first-dimension separation, the target flavonoids were entrapped and subsequently desorbed into the second-dimension high-speed countercurrent chromatographic column for separation. In the third-dimension chromatography, the residual ionic liquid in the four separated flavonoids was removed and the used ionic liquid was recovered. As a result, 35.1 mg of compound 1, 20.4 mg of compound 2, 8.5 mg of compound 3, and 10.6 mg of compound 4 were obtained from 1.53 g R. rosea extract. They were identified as rhodiosin, rhodionin, herbacetin, and kaempferol, respectively. The recovery of ionic liquid reached 99.1% of the initial amount. The results showed that this method is a powerful technology for the separation of R. rosea flavonoids and that the ionic-liquid-based solvent system has advantages over traditional solvent systems in renewable and environmentally friendly properties.

  10. Molecular dynamics simulation of polymer electrolytes based on poly(ethylene oxide) and ionic liquids. II. Dynamical properties

    NASA Astrophysics Data System (ADS)

    Costa, Luciano T.; Ribeiro, Mauro C. C.

    2007-10-01

    Dynamical properties of polymer electrolytes based on poly(ethylene oxide) (PEO) and ionic liquids of 1-alkyl-3-methylimidazolium cations were calculated by molecular dynamics simulations with previously proposed models [L. T. Costa and M. C. Ribeiro, J. Chem. Phys. 124, 184902 (2006)]. The effect of changing the ionic liquid concentration, temperature, and the 1-alkyl-chain lengths, [1,3-dimethylimidazolium]PF6 and [1-butyl-3-methylimidazolium]PF6 ([dmim]PF6 and [bmim]PF6), was investigated. Cation diffusion coefficient is higher than those of anion and oxygen atoms of PEO chains. Ionic mobility in PEO /[bmim]PF6 is higher than in PEO /[dmim]PF6, so that the ionic conductivity κ of the former is approximately ten times larger than the latter. The ratio between κ and its estimate from the Nernst-Einstein equation κ /κNE, which is inversely proportional to the strength of ion pairs, is higher in ionic liquid polymer electrolytes than in polymer electrolytes based on inorganic salts with Li+ cations. Calculated time correlation functions corroborate previous evidence from the analysis of equilibrium structure that the ion pairs in ionic liquid polymer electrolytes are relatively weak. Structural relaxation at distinct spatial scales is revealed by the calculation of the intermediate scattering function at different wavevectors. These data are reproduced with stretched exponential functions, so that temperature and wavevector dependences of best fit parameters can be compared with corresponding results for polymer electrolytes containing simpler ions.

  11. SO₃H-functionalized acidic ionic liquids as catalysts for the hydrolysis of cellulose.

    PubMed

    Liu, Yuanyuan; Xiao, Wenwen; Xia, Shuqian; Ma, Peisheng

    2013-01-30

    The conversion of cellulose into valuable chemicals to deal with the depletion of fossil fuel has got much attention. Completing the hydrolysis of cellulose under mild conditions is the key step. In this study, six kinds of SO(3)H-functionalized acidic ionic liquids were used as acid catalyst to promote the hydrolysis of cellulose in 1-butyl-3-methylimidazolium chloride ([BMIM]Cl). All of them were efficient for the hydrolysis of cellulose, with the maximum total reducing sugars (TRS) yields over 83% at 100 °C. Acidic ionic liquids with analogous structures showed similar catalytic activities. Triethyl-(3-sulfo-propyl)-ammonium hydrogen sulfate (IL-5 in this study) was the optimum ionic liquid for cellulose hydrolysis, with the maximum TRS yield at 100 °C up to 99% when the dosage used was 0.2g. In addition, the water in [BMIM]Cl had negative effect on cellulose hydrolysis. Therefore, controlling the content of water in a comparatively low level is quite necessary.

  12. Why the partition coefficient of ionic liquids is concentration-dependent.

    PubMed

    Köddermann, Thorsten; Reith, Dirk; Arnold, A

    2013-09-19

    The partition coefficient of a substance measures its solubility in octanol compared with water and is widely used to estimate toxicity. If a substance is hardly soluble in octanol, then it is practically impossible for it to enter (human) cells and therefore is less likely to be toxic. For novel drugs it might be important to penetrate the cell through the membrane or even integrate into it. While for most simple substances the partition coefficient is concentration-independent at low concentrations, this is not true for a few important classes of complex molecules, such as ionic liquids or tensides. We present a simple association-dissociation model for concentration dependence of the partition coefficient of ionic liquids. Atomistic computer simulations serve to parametrize our model by calculating solvation free energies in water and octanol using thermodynamic integration. We demonstrate the validity of the method by reproducing the concentration-independent partition coefficients of small alcohols and the concentration-dependent partition coefficient of a commonly used ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [C4MIM][NTf2]. The concentration dependence is accurately predicted in a concentration range of several orders of magnitude.

  13. Oligomerization of n-butenes catalyzed by nickel complexes dissolved in organochloroaluminate ionic liquids

    SciTech Connect

    Chauvin, Y.; Olivier, H.; Wyrvalski, C.N.

    1997-01-15

    The industrial synthesis of higher olefins is generally performed via oligomerization of lower olefins by transition metal complexes or acidic catalysts. The broad variety of olefins that are nowadays produced by these reactions are used as polyethylene co-monomers or as intermediates in the synthesis of detergents, surface active compounds, lubricating oils, and plasticizers. Thus, in the Dimersol{reg_sign} process, butenes are dimerized into C{sub 8} olefins which are usually further hydroformylated giving C{sub 9} alcohols used in the manufacture of plasticizers. In spite of important research efforts devoted to these homogeneous phase oligomerization reactions, activity and conversion still need to be improved. In a more general sense, the separation of the products from the catalyst and the solvent is a major drawback, which leads to increased operational costs and environmental impact. Organochloroaluminate ionic liquids have been envisioned as solvents of nickel catalysts in oligomerization reactions to overcome this technical limitation. The solubility of nickel complexes and the poor solubility of olefins in polar and non-coordinating ionic liquids make possible the separation of the reaction products by simple decantation, with low costs and absence of by-products. In the present article, the authors report the use of 1-butyl-3-methylimidazolium chloro-ethyl-aluminate ionic liquids as solvents in butene oligomerization catalyzed by nickel complexes in a two-phase system. 24 refs., 2 figs., 2 tabs.

  14. Correlation between quasielastic Raman scattering and configurational entropy in an ionic liquid.

    PubMed

    Ribeiro, Mauro C C

    2007-05-10

    Low-frequency (5-200 cm(-1)) Raman spectra are reported for the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate, [bmim]PF(6), in glassy, supercooled liquid, and normal liquid phases (77-330 K). Raman spectra of [bmim]PF(6) agree with previous results obtained by optical Kerr effect spectroscopy and molecular dynamics simulation. Both the superposition model and the coupling model give reasonable fit to low-frequency Raman spectra of [bmim]PF(6). The configurational entropy of [bmim]PF(6) has been evaluated as a function of temperature using recently reported data of heat capacity. The calculated configurational entropy is inserted in the Adam-Gibbs theory for supercooled liquids, giving a good fit to non-Arrhenius behavior of viscosity and diffusive process, with the latter revealed by a recent neutron scattering investigation of [bmim]PF(6). There is a remarkable linear dependence between intensity of quasielastic Raman scattering and configurational entropy from 77 K up to the melting point of [bmim]PF(6). This correlation offers insight into the nature of dynamical processes probed by low-frequency Raman spectra of ionic liquids.

  15. Angle-resolved X-ray photoelectron spectroscopy of the surface of imidazolium ionic liquids.

    PubMed

    Lockett, Vera; Sedev, Rossen; Bassell, Chris; Ralston, John

    2008-03-07

    The surfaces of three imidazolium based ionic liquids with a common anion were studied with angle-resolved X-ray photoelectron spectroscopy (XPS). The room temperature ionic liquids (RTILs): 1-butyl-3-methylimidazolium (bmim), 1-hexyl-3-methylimidazolium (hmim), and 1-octyl-3-methylimidazolium (omim) tetrafluoroborates, were meticulously purified and dried under vacuum. Survey and high-resolution spectra were obtained at different take-off angles (0-84 degrees ), thus increasing the surface sensitivity of the measurement. No impurities were detected and the survey spectra at normal emission (0 degrees ) confirmed the stoichiometric composition of the liquids. However, the spectra at take-off angles of 60, 70, 80 and 84 degrees indicated a higher amount of carbon. High resolution spectra of C1s, at these angles, showed an increased amount of aliphatic carbon when compared to the spectra at normal emission. The longer the side chain (R) of the imidazolium cation (Rmim), the larger was the amount of aliphatic carbon detected. Previous studies with other surface sensitive techniques have yielded contradictory conclusions about the surface orientation of the Rmim. We conclude unequivocally that the alkyl chain of the imidazolium ring of the investigated RTILs is oriented away from the liquid. Our study demonstrates the ability of XPS to probe the structure, along with the composition, of the free liquid surface by comparing signals from different penetration depths.

  16. Effects of ionic liquid and nanogold particles on high-performance liquid chromatography-electrochemical detection and their application in highly efficient separation and sensitive analysis of five phenolic acids in Xuebijing injection.

    PubMed

    Jia, Pu; Wang, Shixiang; Meng, Xue; Lan, Wei; Luo, Jing; Liao, Sha; Xiao, Chaoni; Zheng, Xiaopu; Li, Lianshe; Liu, Qinshe; Zheng, Jianbin; Zhou, Yuanzhen; Zheng, Xiaohui

    2013-03-30

    A novel high performance liquid chromatography-electrochemical detector (HPLC-ECD) analytical system was developed in this study by integratedly utilizing ionic liquid (IL) of 1-butyl-3-methylimidazolium bromide and an additive of gold nanoparticles. The resulted pilot study was first performed to assess the effects of 1-butyl-3-methylimidazolium bromide and gold nanoparticles on the chromatographic characteristics of five phenolic acids in Xuebijing injection, including danshensu (DSS), protocatechuic acid (PA), protocatechuic aldehyde (PAH), hydroxy safflower yellow A (HSYA) and ferulic acid (FA). It was notable to observe that retainability of the phenolic acids were markly lowered by IL addition. Compared with the cases without IL addition, the retention times of DSS, PA, PAH, HSYA and FA have decreased 2.851, 1.532, 1.53, 0.818 and 0.552 min, respectively when 0.6% IL in the mobile phase. In addition, the corresponding theoretical plate numbers and peak areas for these compounds were significantly increased. Area response for DSS, PA, PAH, HSYA and FA were enhanced by 772%, 628%, 584%, 703% and 600%, respectively. It was observed that nano-gold catalysis power enabled peak areas of DSS, PAH, FA and PA to enhance 5.7, 6.2, 8.5 and 66.5 times relative to the case with addition of IL. Altogether, the optimized HPLC-ECD system was successfully applied to the pharmacokinetics study of Xuebijing injection with underlying applicability to in vivo and in vitro analysis of a variety of natural product from Chinese medicine plants, TCM formulae and associated patent TCM preparation.

  17. Layered structure of room-temperature ionic liquids in microemulsions by multinuclear NMR spectroscopic studies.

    PubMed

    Falcone, R Dario; Baruah, Bharat; Gaidamauskas, Ernestas; Rithner, Christopher D; Correa, N Mariano; Silber, Juana J; Crans, Debbie C; Levinger, Nancy E

    2011-06-06

    Microemulsions form in mixtures of polar, nonpolar, and amphiphilic molecules. Typical microemulsions employ water as the polar phase. However, microemulsions can form with a polar phase other than water, which hold promise to diversify the range of properties, and hence utility, of microemulsions. Here microemulsions formed by using a room-temperature ionic liquid (RTIL) as the polar phase were created and characterized by using multinuclear NMR spectroscopy. (1)H, (11)B, and (19)F NMR spectroscopy was applied to explore differences between microemulsions formed by using 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF(4)]) as the polar phase with a cationic surfactant, benzylhexadecyldimethylammonium chloride (BHDC), and a nonionic surfactant, Triton X-100 (TX-100). NMR spectroscopy showed distinct differences in the behavior of the RTIL as the charge of the surfactant head group varies in the different microemulsion environments. Minor changes in the chemical shifts were observed for [bmim](+) and [BF(4)](-) in the presence of TX-100 suggesting that the surfactant and the ionic liquid are separated in the microemulsion. The large changes in spectroscopic parameters observed are consistent with microstructure formation with layering of [bmim](+) and [BF(4)](-) and migration of Cl(-) within the BHDC microemulsions. Comparisons with NMR results for related ionic compounds in organic and aqueous environments as well as literature studies assisted the development of a simple organizational model for these microstructures. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Photochemical synthesis of silver particles in Tween 20/water/ionic liquid microemulsions.

    PubMed

    Harada, Masafumi; Kimura, Yoshifumi; Saijo, Kenji; Ogawa, Tetsuya; Isoda, Seiji

    2009-11-15

    Metal particles of silver (Ag) were synthesized by the photoreduction of silver perchlorate (AgClO(4)) in water-in-ionic liquid (ILs) microemulsions consisting of Tween 20, water and ionic liquids. The ILs were tetrafluoroborate anions associated with the cations 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF(4)]) and 1-octyl-3-methylimidazolium tetrafluoroborate ([OMIm][BF(4)]). The time evolution of Ag particle formation by photoreduction using UV-irradiation was investigated by UV-Vis, cryo-TEM, extended X-ray absorption fine structure (EXAFS) and small angle X-ray scattering (SAXS) measurements. The average diameter of the metallic Ag particles prepared in the water-in-[BMIm][BF(4)] and water-in-[OMIm][BF(4)] microemulsions was estimated from TEM to be 8.9 and 4.9nm, respectively, which was consistent with that obtained from the SAXS analysis. Using Guinier plots in a low q-range (<0.16nm(-1)), we demonstrate that the average diameter of the water droplets that consisted of aggregates of ionic precursors of AgClO(4) before reduction and Ag particles after reduction, in the microemulsions, was estimated to be about 20-40nm. The diameter of the water droplets increased as a function of photoreduction time because of the formation of Ag particles and their aggregates. EXAFS analysis indicated that Ag(+) ions were completely reduced to Ag(0) atoms during the photoreduction, followed by the formation of larger Ag particles.

  19. The electrochemical reduction of the purines guanine and adenine at platinum electrodes in several room temperature ionic liquids.

    PubMed

    Zanoni, Maria Valnice Boldrin; Rogers, Emma I; Hardacre, Christopher; Compton, Richard G

    2010-02-05

    The reduction of guanine was studied by microelectrode voltammetry in the room temperature ionic liquids (RTILs) N-hexyltriethylammonium bis (trifluoromethanesulfonyl) imide [N(6,2,2,2)][N(Tf)(2)], 1-butyl-3-methylimidazolium hexafluorosphosphate [C(4)mim][PF(6)], N-butyl-N-methyl-pyrrolidinium bis(trifluoromethanesulfonyl)imide [C(4)mpyrr][N(Tf)(2)], 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide [C(4)mim][N(Tf)(2)], N-butyl-N-methyl-pyrrolidinium dicyanamide [C(4)mpyrr][N(NC)(2)] and tris(P-hexyl)-tetradecylphosphonium trifluorotris(pentafluoroethyl)phosphate [P(14,6,6,6)][FAP] on a platinum microelectrode. In [N(6,2,2,2)][NTf(2)] and [P(14,6,6,6)][FAP], but not in the other ionic liquids studied, guanine reduction involves a one-electron, diffusion-controlled process at very negative potential to produce an unstable radical anion, which is thought to undergo a dimerization reaction, probably after proton abstraction from the cation of the ionic liquid. The rate of this subsequent reaction depends on the nature of the ionic liquid, and it is faster in the ionic liquid [P(14,6,6,6)][FAP], in which the formation of the resulting dimer can be voltammetrically monitored at less negative potentials than required for the reduction of the parent molecule. Adenine showed similar behaviour to guanine but the pyrimidines thymine and cytosine did not; thymine was not reduced at potentials less negative than required for solvent (RTIL) decomposition while only a poorly defined wave was seen for cytosine. The possibility for proton abstraction from the cation in [N(6,2,2,2)][NTf(2)] and [P(14,6,6,6)][FAP] is noted and this is thought to aid the electrochemical dimerization process. The resulting rapid reaction is thought to shift the reduction potentials for guanine and adenine to lower values than observed in RTILs where the scope for proton abstraction is not present. Such shifts are characteristic of so-called EC processes where reversible electron transfer

  20. A Comprehensive Study on Lyotropic Liquid-Crystalline Behavior of an Amphiphile in 20 Kinds of Amino Acid Ionic Liquids.

    PubMed

    Fujimura, Kanae; Ichikawa, Takahiro; Yoshio, Masafumi; Kato, Takashi; Ohno, Hiroyuki

    2016-02-18

    We examined the self-organization behavior of a designed amphiphilic molecule in 20 kinds of amino acid ionic liquids composed of 1-butyl-3-methylimidazolium cation and natural amino acid anion ([C4mim][AA]). Addition of [C4mim][AA], regardless of their anion species, to the amphiphile provided homogeneous mixtures showing lyotropic liquid-crystalline (LC) behavior. Upon increasing the component ratio of [C4mim][AA] in the mixtures, a successive change of the mesophase patterns from inverted hexagonal columnar, in some case via bicontinuous cubic, to layered phases was observed. By examining the LC properties at various temperatures and component ratios, we constructed lyotropic LC phase diagrams. Interestingly, the appearance of these phase diagrams is greatly different according to the selection of [AA]. Through comparison, we found that the self-organization behavior of an amphiphile in ionic liquids can be tuned by controlling their ability to form hydrogen-bond, van der Waals, and π-π interactions.

  1. Purification of β-mannanase derived from Bacillus subtilis ATCC 11774 using ionic liquid as adjuvant in aqueous two-phase system.

    PubMed

    Aziz, Nur Fazrin Husna Abdul; Abbasiliasi, Sahar; Ng, Hui Suan; Phapugrangkul, Pongsathon; Bakar, Mohamad Hafizi Abu; Tam, Yew Joon; Tan, Joo Shun

    2017-06-15

    The partitioning of β-mannanase derived from Bacillus subtilis ATCC 11774 in aqueous two-phase system (ATPS) was studied. The ATPS containing different molecular weight of polyethylene glycol (PEG) and types of salt were employed in this study. The PEG/salt composition for the partitioning of β-mannanase was optimized using response surface methodology. The study demonstrated that ATPS consists of 25% (w/w) of PEG 6000 and 12.52% (w/w) of potassium citrate is the optimum composition for the purification of β-mannanase with a purification fold (PF) of 2.28 and partition coefficient (K) of 1.14. The study on influences of pH and crude loading showed that ATPS with pH 8.0 and 1.5% (w/w) of crude loading gave highest PF of 3.1. To enhance the partitioning of β-mannanase, four ionic liquids namely 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF4), 1-ethyl-3-methylimidazolium tetrafluoroborate ([Emim]BF4), 1-butyl-3-methylimidazolium bromide ([Bmim]Br), 1-ethyl-3-methylimidazolium bromide ([Emim]Br) was added into the system as an adjuvant. The highest recovery yield (89.65%) was obtained with addition of 3% (w/w) of [Bmim]BF4. The SDS-PAGE analysis revealed that the β-mannanase was successfully recovered in the top phase of ATPS with the molecular size of 36.7kDa. Therefore, ATPS demonstrated a simple and efficient approach for recovery and purification of β-mannanase from fermentation broth in one single-step strategy. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Liquid-liquid extraction of Pu(IV), U(VI) and Am(III) using malonamide in room temperature ionic liquid as diluent.

    PubMed

    Rout, Alok; Venkatesan, K A; Srinivasan, T G; Vasudeva Rao, P R

    2012-06-30

    The extraction behavior of U(VI), Pu(IV) and Am(III) from nitric acid medium by a solution of N,N-dimethyl-N,N-dioctyl-2-(2-hexyloxyethyl)malonamide (DMDOHEMA) in the room temperature ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (C(4)mimNTf(2)), was studied. The distribution ratio of these actinides in DMDOHEMA/C(4)mimNTf(2) was measured as a function of various parameters such as the concentration of nitric acid, DMDOHEMA, NTf(2)(-), alkyl chain length of ionic liquid. The extraction of actinides in the absence of DMDOHEMA was insignificant and the distribution ratio achieved in conjunction with C(4)mimNTf(2), was remarkable. The separation factor of U(VI) and Pu(IV) achieved with the use of DMDOHEMA, ionic liquid was compared with Am(III) and other fission products. The stoichiometry of the metal-solvate was determined to be 1:2 for U(VI) and Pu(IV) and 1:3 for Am(III).

  3. MD simulations of the formation of stable clusters in mixtures of alkaline salts and imidazolium-based ionic liquids.

    PubMed

    Méndez-Morales, Trinidad; Carrete, Jesús; Bouzón-Capelo, Silvia; Pérez-Rodríguez, Martín; Cabeza, Óscar; Gallego, Luis J; Varela, Luis M

    2013-03-21

    Structural and dynamical properties of room-temperature ionic liquids containing the cation 1-butyl-3-methylimidazolium ([BMIM](+)) and three different anions (hexafluorophosphate, [PF6](-), tetrafluoroborate, [BF4](-), and bis(trifluoromethylsulfonyl)imide, [NTf2](-)) doped with several molar fractions of lithium salts with a common anion at 298.15 K and 1 atm were investigated by means of molecular dynamics simulations. The effect of the size of the salt cation was also analyzed by comparing these results with those for mixtures of [BMIM][PF6] with NaPF6. Lithium/sodium solvation and ionic mobilities were analyzed via the study of radial distribution functions, coordination numbers, cage autocorrelation functions, mean-square displacements (including the analysis of both ballistic and diffusive regimes), self-diffusion coefficients of all the ionic species, velocity and current autocorrelation functions, and ionic conductivity in all the ionic liquid/salt systems. We found that lithium and sodium cations are strongly coordinated in two different positions with the anion present in the mixture. Moreover, [Li](+) and [Na](+) cations were found to form bonded-like, long-lived aggregates with the anions in their first solvation shell, which act as very stable kinetic entities within which a marked rattling motion of salt ions takes place. With very long MD simulation runs, this phenomenon is proved to be on the basis of the decrease of self-diffusion coefficients and ionic conductivities previously reported in experimental and computational results.

  4. Optimization of covalent immobilization of Trichoderma reesei cellulase onto modified ReliZyme HA403 and Sepabeads EC-EP supports for cellulose hydrolysis, in buffer and ionic liquids/buffer media.

    PubMed

    Bilgin, Ramazan; Yalcin, M Serkan; Yildirim, Deniz

    2016-08-01

    The covalent immobilization of Trichoderma reesei cellulase onto modified ReliZyme HA403 and Sepabeads EC-EP supports were carried out. The optimal immobilization conditions were determined using response surface methodology. The hydrolysis of cellulose using the free and immobilized cellulase preparations in ionic liquids (IL) using cosolvents was investigated. The hydrolytic activities in buffer medium containing 25% (v/v) of 1-butyl-3-methylimidazolium hexafluorophosphate were around 2.6-, 1.6-, and 5.5-fold higher than the activities in buffer medium. The retained initial activities were 32% and 57%, respectively for cellulase preparations immobilized onto Sepabeads EC-EP support and onto modified ReliZyme HA403 support after 5 reuses.

  5. SEM Observation of Hydrous Superabsorbent Polymer Pretreated with Room-Temperature Ionic Liquids

    PubMed Central

    Tsuda, Tetsuya; Mochizuki, Eiko; Kishida, Shoko; Iwasaki, Kazuki; Tsunashima, Katsuhiko; Kuwabata, Susumu

    2014-01-01

    Room-temperature ionic liquid (RTIL), which is a liquid salt at or below room temperature, shows peculiar physicochemical properties such as negligible vapor pressure and relatively-high ionic conductivity. In this investigation, we used six types of RTILs as a liquid material in the pretreatment process for scanning electron microscope (SEM) observation of hydrous superabsorbent polymer (SAP) particles. Very clear SEM images of the hydrous SAP particles were obtained if the neat RTILs were used for the pretreatment process. Of them, tri-n-butylmethylphosphonium dimethylphosphate ([P4, 4, 4, 1][DMP]) provided the best result. On the other hand, the surface morphology of the hydrous SAP particles pretreated with 1-ethyl-3-methylimidazolium tetrafluoroborate ([C2mim][BF4]) and 1-butyl-3-methylimidazolium tetrafluoroborate ([C4mim][BF4]) was damaged. The results of SEM observation and thermogravimetry analysis of the hydrous SAP pretreated with the RTILs strongly suggested that most water in the SAP particles are replaced with RTIL during the pretreatment process. PMID:24621609

  6. Experimental and numerical investigations of ionic liquid-aqueous flow in microchannel

    NASA Astrophysics Data System (ADS)

    Li, Qi; Tsaoulidis, Dimitrios; Angeli, Panagiota

    2015-11-01

    The hydrodynamic characteristics of plug flow of an ionic liquid-aqueous two-phase system in a microchannel were studied experimentally and numerically. A mixture of 0.2M N-octyl(plenyl)-N,N-diisobutylcarbamoylmethyphosphine oxide (CMOP)- 1.2 M Tri-n-butylphosphate (TBP) in room temperature ionic liquid 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]amide ([C4min][NTf2]), and a nitric acid solution of 1M were chosen. These fluids are relevant Eu(III) separation by extraction from nitric acid solutions. The two liquid phases were introduced into microchannels of 0.2 and 0.5mm internal diameter through a T-junction inlet. The flow pattern was visualized during plug formation at the inlet section and further downstream by means by bright field planar micro-Particle Image Velocimetry. Key features of plug flow, such as plug velocity, film thickness, plug length and recirculation intensity were measured under various experimental conditions. To gain further understanding of the 3-D flow field, Computation Fluid Dynamics (CFD) simulations approach were also conducted.

  7. Effects of ionic liquid as additive and the pH of the mobile phase on the retention factors of amino benzoic acids in RP-HPLC.

    PubMed

    Zheng, J; Polyakova, Y; Row, K H

    2007-01-01

    As an organic salt, ionic liquids are widely used as new solvent media. In this paper, three positional isomers, such as o-amino benzoic acid, m-amino benzoic acid, and p-amino benzoic acid are separated with four different ionic liquids as additives to the mobile phase using reversed-phase (RP) high-performance liquid chromatography (HPLC). Amino benzoic acids are biologically active substances; the p-isomer is present in a group of water-soluble vitamins and is widely known as a sunscreen agent. The ionic liquids used are 1-butyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium methylsulfate, and 1-octyl-3-methylimidazolium methylsulfate. The effects of the length of the alkyl group on the imidazolium ring and its counterion, the concentrations of the ionic liquid, and the effect of the pH of the mobile phase on the retention factor of the amino benzoic acid isomers are studied. Separation with the ionic liquid in the eluent was better than the separation without the ionic liquid. The pH mainly affected the retention and elution order of the solutes in RP-HPLC.

  8. Static and dynamic electrowetting of an ionic liquid in a solid/liquid/liquid system.

    PubMed

    Paneru, Mani; Priest, Craig; Sedev, Rossen; Ralston, John

    2010-06-23

    A droplet of an ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate, bmim.BF(4)) is immersed in an immiscible liquid (n-hexadecane) and electrowetted on a flat Teflon AF1600-coated ITO electrode. The static contact angle decreases significantly when voltage is applied between the droplet and the electrode: from 145 degrees down to 50 degrees (with DC voltage) and 15 degrees (with AC voltage). The electrowetting curves (contact angle versus voltage) are similar to the ones obtained in other solid/liquid/vapor and solid/liquid/liquid systems: symmetric with respect to zero voltage and correctly described by Young-Lippmann equation below saturation. The reversibility is excellent and contact angle hysteresis is minimal (approximately 2 degrees). The step size used in applying the DC voltage and the polarity of the voltage are unimportant. The saturation contact angle cannot be predicted with the simple zero-interfacial tension theory. Spreading (after applying a DC voltage) and retraction (after switching off the voltage) of the droplet is monitored. The base area of the droplet varies exponentially during wetting (exponential saturation) and dewetting (exponential decay). The characteristic time is 20 ms for spreading and 35 ms for retraction (such asymmetry is not observed with water-glycerol mixtures of a similar viscosity). The spreading kinetics (dynamic contact angle versus contact line speed) can be described by the hydrodynamic model (Voinov's equation) for small contact angles and by the molecular-kinetic model (Blake's equation) for large contact angles. The role of viscous and molecular dissipation follows the scheme outlined by Brochard-Wyart and de Gennes.

  9. Self-healing guar gum and guar gum-multiwalled carbon nanotubes nanocomposite gels prepared in an ionic liquid.

    PubMed

    Sharma, Mukesh; Mondal, Dibyendu; Mukesh, Chandrakant; Prasad, Kamalesh

    2013-10-15

    Guar gum is a galactomannan extracted from the seed of the leguminous shrub Cyamopsis tetragonoloba. It was found to form a soft viscoelastic gel in 1-butyl-3-methylimidazolium chloride, an ionic liquid at an optimized concentration of 10%w/v. A nanocomposite gel of the gum with enhanced strength could be prepared with 0.2%w/v of multiwalled carbon nanotubes (MWCNTs) in the ionic liquid. When the gels thus prepared were subjected to surface fractures or bisected completely, they found to self-heal at room temperature without any external interventions. The self-healing process could be repeated several times. These viscoelastic gel systems showed thixotropic nature and recovery of the storage modulus with time for several cycles was observed upon rheological investigations. The interaction took place between ionic liquid, guar gum and MWCNT was studied by SEM, TEM, FT-IR, powder XRD and rheometry. The results suggested that, upon standing at room temperature development of electrostatic interactions and the van der Waals interactions among the ionic liquid molecules facilitated the formation of reversible noncovalent bonds and eventually activated the self-healing in the gel systems through appropriate chain entanglements.

  10. New insight into the environmental impact of two imidazolium ionic liquids. Effects on seed germination and soil microbial activity.

    PubMed

    Salgado, J; Parajó, J J; Teijeira, T; Cruz, O; Proupín, J; Villanueva, M; Rodríguez-Añón, J A; Verdes, P V; Reyes, O

    2017-10-01

    The next generation of ionic liquids must be synthetized taking into account structures that guarantee the suitable properties for a defined application as well as ecological data. Thus, searching of the right methodologies to know, quickly and efficiently, the ecological effects of these compounds is a preliminary task. The effects of two imidazolium based ionic liquids with different anions, 1-butyl-3-methylimidazolium tetrafluoroborate, [C4C1Im][BF4], and 1-propyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [C3C1Im][NTf2], on seedling emergence of six tree species and on the microbial behaviour of two soils were determined in this work. Results showed that the highest doses of both ionic liquids caused the total inhibition of germination for almost all the species studied and that the seeds are more sensitive to the presence of these compounds than soil microbial activity. Nevertheless, signals of stress and death are observed from the results of heat released by microorganisms after the addition of the highest doses of both ionic liquids. The novelty of this work resides in the enlargement of knowledge of toxicity of ILs on complex organisms such as arboreal species and microbial activity of soils studied for the first time through a microcalorimetric technique. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. On the importance of simultaneous infrared/fiber-optic temperature monitoring in the microwave-assisted synthesis of ionic liquids.

    PubMed

    Obermayer, David; Kappe, C Oliver

    2010-01-07

    The temperature profiles obtained from both an external infrared and internal fiber-optic sensor were compared for heating and synthesizing the ionic liquid 1-butyl-3-methylimidazolium bromide (bmimBr) under microwave conditions. Utilizing a single-mode microwave reactor that allows simultaneous infrared/fiber-optic temperature measurements, significant differences between the two methods of temperature monitoring were revealed. Due to the strong microwave absorptivity of ionic liquids and the delay experienced in monitoring temperature on the outer surface of a heavy-walled glass vial, external infrared temperature sensors can not be used to accurately control the temperature in the heating of ionic liquids under microwave conditions. The use of internal fiber-optic probes allows the monitoring and control of the heating behavior in a much better way. In order to prevent the strong exotherm in the synthesis of bmimBr under microwave conditions the use of a reaction vessel made out of silicon carbide is the method of choice. Because of the high thermal conductivity and effusivity of silicon carbide, the heat generated during the ionic liquid formation is efficiently exchanged with the comparatively cool air in the microwave cavity via the silicon carbide ceramic.

  12. Ligandless ultrasonic-assisted and ionic liquid-based dispersive liquid-liquid microextraction of copper, nickel and lead in different food samples.

    PubMed

    Jalbani, N; Soylak, M

    2015-01-15

    A simple and rapid ultrasonic assisted-ionic liquid based-liquid-liquid microextraction (UA-IL-DLLME) method has been developed for the enrichment and separation of Cu(II), Ni(II) and Pb(II). A two level factorial design was used to determine the effect of key factors such as pH, volume of ionic liquid (IL), carbon tetra chloride (CCl4) and sonication time (St). 1-Butyl-3-methylimidazolium hexafluorophosphate ([C4MIM][PF6]) and CCl4 were used as an extractant and dispersant solvent, respectively. The accuracy of the proposed method was evaluated by analysing of SRM Apple Leaves 1515 certified reference material. The limits of detections (LODs) were 0.17 μg/L, 0.49 μg/L and 0.95 μg/L for Cu, Ni and Pb, respectively. The enrichment factor (EF) was 100. The method has been successfully applied for the analysis of the content of Cu, Ni and Pb in spice, vegetable and fruit samples by flame atomic absorption spectrometry (FAAS).

  13. Nonaqueous CE using contactless conductivity detection and ionic liquids as BGEs in ACN.

    PubMed

    Borissova, Maria; Gorbatsova, Jelena; Ebber, Arkadi; Kaljurand, Mihkel; Koel, Mihkel; Vaher, Merike

    2007-10-01

    N,N'-Alkylmethylimidazolium cations have been separated in NACE when one of the N,N'-dialkylimidazolium salts (ionic liquids (ILs)) was used as an electrolyte additive to the organic solvent separation medium. The separated species were 1-methyl-, 1-ethyl-, 1-butyl-, 1-octyl-, 1-decyl-3-methylimidazolium and N-butyl-3-methylpyridinium cations and BGE composed of 1-ethyl-3-methylimidazolium ethylsulfate or 1-butyl-3-methylimidazolium trifluoroacetate [BMIm][FAcO] (A6; B2) diluted in ACN. It was demonstrated that contactless conductivity detection (CCD) may be applied to monitoring the separation process in nonaqueous separation media, allowing to use the UV light-absorbing imidazolium-based electrolyte additives. There could be marked three concentration regions of added ILs; at first ionic strength of BGE below 1-2 mM, and then the actual electrophoretic mobility of analytes rises from 0. At concentrations above 1-2 mM, the added IL facilitated separation. In concentration region of 1-20 mM, the actual electrophoretic mobility of analyzed imidazolium cations was increasing with decrease in separation medium ionic strength. At higher concentrations of BGE (above 30 mM), the conductivity of the separation media became too high for this detector. Some organic dyes were also successfully separated and detected by contactless conductivity detector in a 20 mM A6 separation electrolyte in ACN.

  14. Association structures of ionic liquid/DMSO mixtures studied by high-pressure infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Jiang, Jyh-Chiang; Lin, Kuan-Hung; Li, Sz-Chi; Shih, Pao-Ming; Hung, Kai-Chan; Lin, Sheng Hsien; Chang, Hai-Chou

    2011-01-01

    Using high-pressure infrared methods, we have investigated close interactions of charge-enhanced C-H-O type in ionic liquid/dimethyl sulfoxide (DMSO) mixtures. The solvation and association of the 1-butyl-3-methylimidazolium tetrafluoroborate (BMI^ + BF_4^ - ) and 1-butyl-2,3-dimethylimidazolium tetrafluoroborate (BMM^ + BF_4^ - ) in DMSO-d6 were examined by analysis of C-H spectral features. Based on our concentration-dependent results, the imidazolium C-H groups are more sensitive sites for C-H-O than the alkyl C-H groups and the dominant imidazolium C-H species in dilute ionic liquid/DMSO-d6 should be assigned to the isolated (or dissociated) structures. As the dilute mixtures were compressed by high pressures, the loss in intensity of the bands attributed to the isolated structures was observed. In other words, high pressure can be used to perturb the association-dissociation equilibrium in the polar region. This result is remarkably different from what is revealed for the imidazolium C-H in the BMM^ + BF_4^ - /D2O mixtures. DFT-calculations are in agreement with our experimental results indicating that C4-H-O and C5-H-O interactions seem to play non-negligible roles for BMM^ + BF_4^ - /DMSO mixtures.

  15. An ionic liquid as a solvent for headspace single drop microextraction of chlorobenzenes from water samples.

    PubMed

    Vidal, Lorena; Psillakis, Elefteria; Domini, Claudia E; Grané, Nuria; Marken, Frank; Canals, Antonio

    2007-02-12

    A headspace single-drop microextraction (HS-SDME) procedure using room temperature ionic liquid and coupled to high-performance liquid chromatography capable of quantifying trace amounts of chlorobenzenes in environmental water samples is proposed. A Plackett-Burman design for screening was carried out in order to determine the significant experimental conditions affecting the HS-SDME process (namely drop volume, aqueous sample volume, stirring speed, ionic strength, extraction time and temperature), and then a central composite design was used to optimize the significant conditions. The optimum experimental conditions found from this statistical evaluation were: a 5 microL microdrop of 1-butyl-3-methylimidazolium hexafluorophosphate, exposed for 37 min to the headspace of a 10 mL aqueous sample placed in a 15 mL vial, stirred at 1580 rpm at room temperature and containing 30% (w/v) NaCl. The calculated calibration curves gave a high level of linearity for all target analytes with correlation coefficients ranging between 0.9981 and 0.9997. The repeatability of the proposed method, expressed as relative standard deviation, varied between 1.6 and 5.1% (n=5). The limits of detection ranged between 0.102 and 0.203 microg L(-1). Matrix effects upon extraction were evaluated by analysing spiked tap and river water as well as effluent water samples originating from a municipal wastewater treatment plant.

  16. Reactions of excited-state benzophenone ketyl radical in a room-temperature ionic liquid.

    PubMed

    Takahashi, Kenji; Tezuka, Hiroaki; Kitamura, Shingo; Satoh, Toshifumi; Katoh, Ryuzi

    2010-02-28

    The photochemistry of the benzophenone ketyl radical in D(1) excited state, BPH(D(1)), was studied by means of two-color dual-pulse laser flash photolysis (355 and 532 nm) in a room-temperature ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide (Bmim-TFSA), and in methanol. Upon excitation with the 532 nm pulse, BPH(D(1)) emitted strong fluorescence. The transient absorption and fluorescence spectra of BPH(D(1)) were measured with nanosecond and sub-nanosecond time resolution, respectively. The observed Stokes shift was 1700 cm(-1) in Bmim-TFSA, and this shift was close to that in acetonitrile. The fluorescence lifetime of BPH(D(1)) was determined to be 5 ns in Bmim-TFSA, and again the value was close to that in acetonitrile. The rate constant of the reaction of BPH(D(1)) with CCl(4) in Bmim-TFSA was determined to be (2.1 +/- 0.4) x 10(9) M(-1) s(-1), which was 10 times the rate constant calculated on the basis of the bulk viscosity of Bmim-TFSA. The results are discussed in terms of the effective microscopic viscosity of the ionic liquid that was recently reported for the cage effect.

  17. Ionic liquid-assisted sonochemical preparation of CeO2 nanoparticles for CO oxidation

    DOE PAGES

    Alammar, Tarek; Noei, Heshmat; Wang, Yuemin; ...

    2014-10-10

    CeO2 nanoparticles were synthesized via a one-step ultrasound synthesis in different kinds of ionic liquids based on bis(trifluoromethanesulfonylamide, [Tf2N]–, in combination with various cations including 1-butyl-3-methylimidazolium ([C4mim]+), 1-ethyl-2,3-dimethylimidazolium ([Edimim]+), butyl-pyridinium([Py4]+), 1-butyl-1-methyl-pyrrolidinium ([Pyrr14]+), and 2-hydroxyethyl-trimethylammonium ([N1112OH]+). Depending on synthetic parameters, such as ionic liquid, Ce(IV) precursor, heating method, and precipitator, formed ceria exhibits different morphologies, varying from nanospheres, nanorods, nanoribbons, and nanoflowers. The morphology, crystallinity, and chemical composition of the obtained materials were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX), Raman spectroscopy, and N2 adsorption. The structural and electronic propertiesmore » of the as-prepared CeO2 samples were probed by CO adsorption using IR spectroscopy under ultrahigh vacuum conditions. The catalytic activities of CeO2 nanoparticles were investigated in the oxidation of CO. CeO2 nanospheres obtained sonochemically in [C4mim][Tf2N] exhibit the best performance for low-temperature CO oxidation. As a result, the superior catalytic performance of this material can be related to its mesoporous structure, small particle size, large surface area, and high number of surface oxygen vacancy sites.« less

  18. Ionic liquid-assisted sonochemical preparation of CeO2 nanoparticles for CO oxidation

    DOE PAGES

    Alammar, Tarek; Noei, Heshmat; Wang, Yuemin; ...

    2014-10-10

    CeO2 nanoparticles were synthesized via a one-step ultrasound synthesis in different kinds of ionic liquids based on bis(trifluoromethanesulfonylamide, [Tf2N]–, in combination with various cations including 1-butyl-3-methylimidazolium ([C4mim]+), 1-ethyl-2,3-dimethylimidazolium ([Edimim]+), butyl-pyridinium([Py4]+), 1-butyl-1-methyl-pyrrolidinium ([Pyrr14]+), and 2-hydroxyethyl-trimethylammonium ([N1112OH]+). Depending on synthetic parameters, such as ionic liquid, Ce(IV) precursor, heating method, and precipitator, formed ceria exhibits different morphologies, varying from nanospheres, nanorods, nanoribbons, and nanoflowers. The morphology, crystallinity, and chemical composition of the obtained materials were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX), Raman spectroscopy, and N2 adsorption. The structural and electronic propertiesmore » of the as-prepared CeO2 samples were probed by CO adsorption using IR spectroscopy under ultrahigh vacuum conditions. The catalytic activities of CeO2 nanoparticles were investigated in the oxidation of CO. CeO2 nanospheres obtained sonochemically in [C4mim][Tf2N] exhibit the best performance for low-temperature CO oxidation. As a result, the superior catalytic performance of this material can be related to its mesoporous structure, small particle size, large surface area, and high number of surface oxygen vacancy sites.« less

  19. Counterintuitive trends of the wetting behavior of ionic liquid-based electrolytes on modified lithium electrodes.

    PubMed

    Schmitz, Paulo; Kolek, Martin; Diddens, Diddo; Stan, Marian Cristian; Jalkanen, Kirsi; Winter, Martin; Bieker, Peter

    2017-07-26

    The demand for high energy densities has brought rechargeable lithium metal batteries back into the research focus. Ionic liquids (ILs) are considered as suitable electrolyte components for these systems. In this work, the wetting behavior of 1-ethyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)imide ([C2MIm]TFSI), 1-butyl-3-methylimidazolium bis-((trifluoromethyl)sulfonyl)imide ([C4MIm]TFSI), 1-hexyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)imide ([C6MIm]TFSI), and N-butyl-N-methylpyrrolidinium bis((trifluoromethyl)sulfonyl)imide (Pyr14TFSI) on mechanically modified lithium electrodes, with and without lithium bis((trifluoromethyl)sulfonyl)imide (LiTFSI) conducting salt, is investigated and is compared to an organic carbonate-based electrolyte. Three different patterns were chosen for the lithium modification, enabling a surface area increase of 12%, 20%, and 56% for the modified lithium electrodes. Especially for pure ILs, the contact angle on lithium was significantly larger with higher surface areas of the lithium electrodes. Since the addition of LiTFSI remarkably decreased the contact angles of the ILs on the modified lithium surfaces, it could be shown that the effect of LiTFSI can be attributed to a decreased surface tension. This observation could be explained by an interruption of the ordering of ionic liquid cations and anions, which is supported by Raman spectroscopy and molecular dynamics (MD) simulations.

  20. Comparative ecotoxicology study of two neoteric solvents: Imidazolium ionic liquid vs. glycerol derivative.

    PubMed

    Perales, Eduardo; García, Cristina Belén; Lomba, Laura; Aldea, Luis; García, José Ignacio; Giner, Beatriz

    2016-10-01

    In this study we have compared the acute ecotoxicity of two solvents, with very different structure and origin, but sharing many physical-chemical properties, so they can be used for similar purposes; a well-known ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) and a solvent partially derived from biomass, 3-bis(2,2,2-trifluoroethoxy)propan-2-ol (BTFIP). We have used three biomodels (Vibrio fischeri, Daphnia magna and Danio rerio) and performed the comparison applying the Environmental, Health and Safety (EHS) hazard assessment. According to the results, ecotoxicity of [BMIM][PF6] and BTFIP is quite similar in the simplest model Vibrio fischeri, while in Daphnia magna [BMIM][PF6] is clearly more toxic. However, in Danio rerio, toxicity of these chemicals is again quite similar and both can be classified as "nontoxic". The higher index value of [BMIM][PF6] in water mediate effect in the EHS assessment indicates that this ionic liquid is more dangerous than BTFIP, although accumulation and degradation properties have not been taken into account. Further studies will be necessary to ascertain these conclusions.

  1. Direct proteins electrochemistry based on ionic liquid mediated carbon nanotube modified glassy carbon electrode.

    PubMed

    Zhao, Qiang; Zhan, Dongping; Ma, Hongyang; Zhang, Meiqin; Zhao, Yifang; Jing, Ping; Zhu, Zhiwei; Wan, Xinhua; Shao, Yuanhua; Zhuang, Qiankun

    2005-01-01

    A novel glassy carbon electrode modified by a gel containing multi-walled carbon nanotubes (MWNTs) and ionic liquid of 1-butyl-3-methylimidazolium hexafluorophosphate (BMIPF6) is reported. The gel is formed by grinding of MWNTs and BMIPF6. Such gel is then coated on the surface of a glassy carbon electrode. We have employed scanning electron microscopy, Fourier transform infrared spectrometry (FTIR) and cyclic voltammetry to characterize the modified electrode. The direct electron transfers of hemoglobin and catalase on the modified electrode have been observed and studied in detail electrochemically. Hemoglobin is verified to be adsorbed on the modified electrode with the retention of conformation, which has been proved by microscopic FTIR. The electrochemical response of the adsorbed hemoglobin on the modified electrode is very stable, and shows repeated changes in the different pH solutions. It also has shown electrocatalysis to the reduction of oxygen and trichloroacetic acid. Catalase adsorbed on the gel modified electrode still keep activity to hydrogen peroxide. This work provides a simple and easy approach to construct biosensors based on the carbon nanotubes and ionic liquids.

  2. Thermal stability, complexing behavior, and ionic transport of polymeric gel membranes based on polymer PVdF-HFP and ionic liquid, [BMIM][BF4].

    PubMed

    Shalu; Chaurasia, S K; Singh, R K; Chandra, S

    2013-01-24

    PVdF-HFP + IL(1-butyl-3-methylimidazolium tetrafluoroborate; [BMIM][BF(4)]) polymeric gel membranes containing different amounts of ionic liquid have been synthesized and characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared (FTIR), differential scanning calorimetry, thermogravimetric analysis (TGA), and complex impedance spectroscopic techniques. Incorporation of IL in PVdF-HFP polymer changes different physicochemical properties such as melting temperature (T(m)), thermal stability, structural morphology, amorphicity, and ionic transport. It is shown by FTIR, TGA (also first derivative of TGA, "DTGA") that IL partly complexes with the polymer PVdF-HFP and partly remains dispersed in the matrix. The ionic conductivity of polymeric gel membranes has been found to increase with increasing concentration of IL and attains a maximum value of 1.6 × 10(-2) S·cm(-1) for polymer gel membrane containing 90 wt % IL at room temperature. Interestingly, the values of conductivity of membranes with 80 and 90 wt % of IL were higher than that of pure IL (100 wt %). The polymer chain breathing model has been suggested to explain it. The variation of ionic conductivity with temperature of these gel polymeric membranes follows Arrhenius type thermally activated behavior.

  3. Video-microscopic observation of ionic liquid/alcohol interface and the corresponding molecular simulation study

    NASA Astrophysics Data System (ADS)

    Zhu, Peixi

    This research is aimed at studying the ionic liquid/n-pentanol interface via video-microscopy and molecular dynamic simulations. Understanding the interfacial phenomena and interfacial transport between ionic liquids and other liquids is of interest to the development and application of ionic liquids in a number of areas. One such area is the biphasic hydroformylation of alkenes to obtain alcohol and aldehyde, in which case ionic liquid is the reaction medium where a catalyst resides. The dissolution of an ionic liquid into an alcohol was studied by microscopically observing and measuring the shrinking of a micropipette-produced droplet in real time. Although microscopic investigation of droplet dissolution has been studied before, no attempt had been made to measure the diffusion coefficient D of the droplet species in the surrounding medium. A key finding of this work is that the Epstein-Plesset mathematical model, which describes the dissolution of a droplet/bubble in another fluid medium, can be used to measure D. Other experimental studies of the ionic liquid/alcohol system include electrical conductivity and UV-visible spectroscopy measurements of solutions of 1-hexyl-3-methylimidazolium tetrafluoroborate in n-pentanol. Those experiments were done in order to understand the molecular state of the particular ionic liquid in n-pentanol, as well as obtaining the dissociation constant K of such weak electrolyte solution. The experimental results provide an entry to the assessment of ionic liquid interaction with n-pentanol at molecular scale. Subsequently, molecular dynamics simulation was implemented for the investigation of such interaction. The computation started with simulation of the bulk phase of 1-butyl-3-methylimidazolium tetrafluoroborate, an affine ionic liquid on which molecular simulations had already been reported. A generalized probability based on Fuoss approximation for the closest ion to a distinguished countercharge ion was developed. In

  4. Double layer in room temperature ionic liquids: influence of temperature and ionic size on the differential capacitance and electrocapillary curves.

    PubMed

    Costa, Renata; Pereira, Carlos M; Silva, Fernando

    2010-09-28

    Differential capacity-potential curves, C(E), were obtained from electrochemical impedance spectra (12 kHz-2 Hz) for the interfaces between Hg and a series of alkyl imidazolium-based room temperature ionic liquids having the same anion, bis(trifluoromethanesulfonyl) imide: 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl) imide [EMIM][Tf(2)N], 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl) imide [BMIM][Tf(2)N], 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl) imide [HMIM][Tf(2)N]. The electrocapillary curves were obtained from drop time measurements and the values of the pzc were calculated. The pzc apparently becomes more negative as the imidazolium alkyl chain length increases. A small effect of the cation is seen on the C(E) curves at negative potentials. The effect of the aromatic nature of the cation is assessed by comparing 1-butyl-1-methylimidazolium bis(trifluoromethanesulfonyl) imide, with 1-butyl-3-methylpyrrolidinium bis(trifluoromethanesulfonyl) imide [BMPyr][Tf(2)N]. The effects of temperature on the capacitance, drop time electrocapillary curve and on the pzc were also obtained. The capacity was found to increase with increasing temperature in the whole range of accessible potentials.

  5. Genotoxicity, mutagenicity and cytotoxicity of carotenoids extracted from ionic liquid in multiples organs of Wistar rats.

    PubMed

    Larangeira, Paula Martins; de Rosso, Veridiana Vera; da Silva, Victor Hugo Pereira; de Moura, Carolina Foot Gomes; Ribeiro, Daniel Araki

    2016-11-01

    The ionic liquid or melted salt 1-Butyl-3-methylimidazolium is an alternative process to extract natural pigments, such as carotenoids. Lycopene represents 80-90% of total of carotenoids presents in tomatoes and it has been widely studied due its potent antioxidant action. The aim of this study was to evaluate genotoxicity, mutagenicity and cytotoxicity of carotenoids extracted from ionic liquid using experimental model in vivo. For this purpose, a total of 20 male Wistar rats were distributed into four groups (n=5), as follows: control group; received a corresponding amount of corn oil for 7days by intragastric gavage (i.g.), ionic liquid group, received 10mgkg(-1) body weight for 7days by gavage; 10mg carotenoids group, received 10mgkg(-1) bw dissolved in corn oil for 7days by gavage and 500mg carotenoids group, received 500mgkg(-1) bw dissolved in corn oil for 7days by gavage. Rat liver treated with ionic liquid exhibited moderate histopathological changes randomly distributed in the parenchyma, such as cytoplasmic eosinophilia, apoptotic bodies, inflammatory infiltrate and focal necrosis. DNA damage was found in peripheral blood and liver cells of rats treated with ionic liquid or carotenoids at 500mg. An increase of micronucleated cells and 8-OhDG immunopositive cells were also detected in rats treated with carotenoids at 500mg. In summary, our results demonstrate that recommended dose for human daily intake of carotenoids extracted by ionic liquid did not induce genotoxicity, mutagenicity and cytotoxicity in multiple organs of rats. Copyright © 2016 Elsevier GmbH. All rights reserved.

  6. Separation and pre-concentration of glucocorticoids in water samples by ionic liquid supported vortex-assisted synergic microextraction and HPLC determination.

    PubMed

    Qin, Hui; Li, Bi; Liu, Mou Sheng; Yang, Ya Ling

    2013-04-01

    We have developed a synergic microextraction procedure based on ionic liquid for the pre-concentration and determination of glucocorticoids in water samples. Using nonionic surfactant Triton X-100 (TX-100) as synergic reagent, 1-butyl-3-methylimidazolium hexa-fluorophosphate accomplished extraction rapidly without heating in water bath. One key property of ionic liquids that highlights their potential is their wide liquid temperature range. The improved extraction was named as ionic liquid supported vortex-assisted synergic microextraction. Compared with the traditional liquid-liquid extraction and cloud point extraction, ionic liquid supported vortex-assisted synergic microextraction was accomplished in 8 min with considerably high recovery. The proposed method greatly improved the sensitivity of HPLC for the determination of glucocorticoids. The results obtained indicated a good linearity with the correlation coefficient of 0.997 over the range of 0.6-300 ng/mL and high sensitivity with LODs of 4.11, 9.19, and 7.50 ng/mL for hydrocortisone butyrate, beclomethasone dipropionate, and nandrolone phenylpropionate, respectively. The RSD of the method was 1.57-1.81% (n = 6) with enrichment factor of 99.85, and good recovery (≥97.24%). The method was successfully applied to the determination of glucocorticoids in mineral water, water of Dianchi lake, and tap water samples.

  7. Targeting adequate thermal stability and fire safety in selecting ionic liquid-based electrolytes for energy storage.

    PubMed

    Chancelier, L; Diallo, A O; Santini, C C; Marlair, G; Gutel, T; Mailley, S; Len, C

    2014-02-07

    The energy storage market relating to lithium based systems regularly grows in size and expands in terms of a portfolio of energy and power demanding applications. Thus safety focused research must more than ever accompany related technological breakthroughs regarding performance of cells, resulting in intensive research on the chemistry and materials science to design more reliable batteries. Formulating electrolyte solutions with nonvolatile and hardly flammable ionic liquids instead of actual carbonate mixtures could be safer. However, few definitions of thermal stability of electrolytes based on ionic liquids have been reported in the case of abuse conditions (fire, shortcut, overcharge or overdischarge). This work investigates thermal stability up to combustion of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C1C4Im][NTf2]) and 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ([PYR14][NTf2]) ionic liquids, and their corresponding electrolytes containing lithium bis(trifluoromethanesulfonyl)imide LiNTf2. Their possible routes of degradation during thermal abuse testings were investigated by thermodynamic studies under several experimental conditions. Their behaviours under fire were also tested, including the analysis of emitted compounds.

  8. Self-Assembled Functional Nanostructure of Plasmid DNA with Ionic Liquid [Bmim][PF₆]: Enhanced Efficiency in Bacterial Gene Transformation.

    PubMed

    Soni, Sarvesh K; Sarkar, Sampa; Mirzadeh, Nedaossadat; Selvakannan, P R; Bhargava, Suresh K

    2015-04-28

    The electrostatic interaction between the negatively charged phosphate groups of plasmid DNA and the cationic part of hydrophobic ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim][PF6]), initiates spontaneous self-assembly to form the functional nanostructures made up of DNA and ionic liquid (IL). These functional nanostructures were demonstrated as promising synthetic nonviral vectors for the efficient bacterial pGFP gene transformation in cells. In particular, the functional nanostructures that were made up of 1 μL of IL ([Bmim][PF6]) and 1 μg of plasmid DNA can increase the transformation efficiency by 300-400% in microbial systems, without showing any toxicity for E. coli DH5α cells. (31)P nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron (XPS) spectroscopic analysis revealed that the electrostatic interaction between negatively charged phosphate oxygen and cationic Bmim(+) tends to initiate the self-assembly process. Thermogravimetric analysis of the DNA-IL functional nanostructures showed that these nanostructures consist of ∼16 wt % ionic liquid, which is considered to provide the stability to the plasmid DNA that eventually enhanced the transformation efficiency.

  9. Interfacial properties of an ionic liquid by molecular dynamics.

    PubMed

    Heggen, Berit; Zhao, Wei; Leroy, Frédéric; Dammers, Anton J; Müller-Plathe, Florian

    2010-05-27

    We studied the influence of a liquid-vapor interface on dynamic properties like reorientation and diffusion as well as the surface tension of the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF(6)]) by molecular dynamics simulations. In the interfacial region, reorientation of a short molecular axis is slightly faster than that in the central layer, while that of the longer molecular axis is retarded. The molecular reorientation is well-described by a stretched exponential decay modeled by the Kohlrausch-Williams-Watts equation. Analysis of the average translational diffusion coefficient of molecules in a central layer shows consistency with the Vogel-Fulcher-Tamann equation in a temperature range from 300 to 380 K. A first-passage time analysis of the system at 380 K yields a more refined spatial characterization of translational diffusion perpendicular to the liquid-vapor interfaces. In the central region of the slab, the diffusion coefficient of cations is only marginally higher than that of anions, but close to an interface, this difference is much higher, up to 50%. Apparent activation energies for rotational and diffusional dynamics, respectively, were estimated assuming Arrhenius behavior. They indicate that reorientation of the long molecular axis depends on the diffusion ability, whereas for the reorientation of the short axis, no such correlation is observed. The results are in general agreement with the literature, with slightly overestimated absolute values. This applies as well for the surface tension, where, however, a dependence on the treatment of the electrostatics was found. Particle-mesh Ewald (PME) or reaction field (RF) and the treatment of bonds by constraints have an influence. If no bond constraints are applied, the results are consistent for both methods for the description of the electrostatics.

  10. Ionic liquid mediated extraction, assisted by ultrasound energy, of available/mobilizable metals from sediment samples.

    PubMed

    Álvarez, Silvana M; Llamas, Natalia E; Lista, Adriana G; Álvarez, Mónica B; Domini, Claudia E

    2017-01-01

    A new extraction method for metals from sediment samples was developed. In this procedure, the chelating agent EDTA was combined with a minimal amount of the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate (Bmim[BF4]), assisted by ultrasound energy. The available analytes -Cd, Cr, Cu, Ni, Pb and Zn- were extracted under optimal conditions for a 12.5 ratio (extractant volume/sample mass) with 0.005molL(-1) EDTA solution, 0.1molL(-1) NaHCO3, 5.0mmolL(-1) Bmim[BF4] and 7.0min of sonication time, using an ultrasonic bath (output power of 160W). The best extractions were obtained with 100W (power dissipated in the liquid). These conditions were obtained applying the univariate method. It is important to highlight that the conventional method (extraction with 0.05molL(-1) EDTA solution only) consumes 6h to extract available metals from sediment samples selectively, and with the proposed procedure the extraction time is noticeable reduced to 7.0min. Extractable metal concentrations obtained were measured by flame atomic absorption spectrometry. The results showed good agreement with those obtained by the conventional method using a Student's paired t-test. Published by Elsevier B.V.

  11. Ionic liquid-based aqueous two-phase system extraction of sulfonamides in milk.

    PubMed

    Shao, Mingyuan; Zhang, Xuli; Li, Na; Shi, Jiayuan; Zhang, Huijie; Wang, Zhibing; Zhang, Hanqi; Yu, Aimin; Yu, Yong

    2014-06-15

    A simple method for the determination of six sulfonamides (SAs) in milk samples was developed. 1-Butyl-3-methylimidazolium tetrafluoroborate and trisodium citrate dihydrate were used to form aqueous two-phase system. The aqueous two phase system was applied to the extraction of the SAs and the determination of the analytes was performed by high-performance liquid chromatography. To achieve optimum extraction performance, several experimental parameters, including the type and the amount of salt, the type and amount of ionic liquid, ultrasonic time and pH of sample solution, were investigated and optimized. Under the optimal experimental conditions, good linearity was observed in the range of 8.55-1036.36ngmL(-1). The limits of detection and quantification were in the range of 2.04-2.84 and 6.73-9.37ngmL(-1), respectively. The present method was successfully applied to the determination of SAs in milk samples, and the recoveries of analytes were in the range of 72.32-108.96% with relative standard deviations ranging from 0.56 to 12.20%. The results showed that the present method was rapid, feasible and environmentally friendly.

  12. Molecular dynamics studies on the adaptability of an ionic liquid in the extraction of solid nanoparticles.

    PubMed

    Frost, Denzil S; Machas, Michael; Dai, Lenore L

    2012-10-02

    Recently, a number of publications have suggested that ionic liquids (ILs) can absorb solid particles. This development may have implications in fields like oil sand processing, oil spill beach cleanup, and water treatment. In this Article, we provide a computational investigation of this phenomenon via molecular dynamics simulations. Two particle surface chemistries were investigated: (1) hydrocarbon-saturated and (2) silanol-saturated, representing hydrophobic and hydrophilic particles, respectively. Employing 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF(6)]) as a model IL, these nanoparticles were allowed to equilibrate at the IL/water and IL/hexane interfaces to observe the interfacial self-assembled structures. At the IL/water interface, the hydrocarbon-based nanoparticles were nearly completely absorbed by the IL, while the silica nanoparticles maintained equal volume in both phases. At the IL/hexane interface, the hydrocarbon nanoparticles maintained minimal interactions with the IL, whereas the silica nanoparticles were nearly completely absorbed by it. Studies of these two types of nanoparticles immersed in the bulk IL indicate that the surface chemistry has a great effect on the corresponding IL liquid structure. These effects include layering of the ions, hydrogen bonding, and irreversible absorption of some ions to the silica nanoparticle surface. We quantify these effects with respect to each nanoparticle. The results suggest that ILs likely exhibit this absorption capability because they can form solvation layers with reduced dynamics around the nanoparticles.

  13. Non-volatile polymer electrolyte based on poly(propylene carbonate), ionic liquid, and lithium perchlorate for electrochromic devices.

    PubMed

    Zhou, Dan; Zhou, Rui; Chen, Chuanxiang; Yee, Wu-Aik; Kong, Junhua; Ding, Guoqiang; Lu, Xuehong

    2013-06-27

    A series of solvent-free ionic liquid (IL)-based polymer electrolytes composed of amorphous and biodegradable poly(propylene carbonate) (PPC) host, LiClO4, and 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM(+)BF4(-)) were prepared and characterized for the first time. FTIR studies reveal that the interaction between PPC chains and imidazolium cations weakens the complexation between PPC chains and Li(+) ions. Thermal analysis (DSC and TGA) results show that the incorporation of BMIM(+)BF4(-) into PPC/LiClO4 remarkably decreases the glass transition temperature and improves the thermal stability of the electrolytes. AC impedance results show that the ionic conductivities of the electrolytes are significantly increased with the increase of BMIM(+)BF4(-) amount, the ambient ionic conductivity of the electrolyte at a PPC/LiClO4/BMIM(+)BF4(-) weight ratio of 1/0.2/3 is 1.5 mS/cm, and the ionic transport behavior follows the Arrhenius equation. Both PPC/LiClO4/BMIM(+)BF4(-) and PPC/BMIM(+)BF4(-) electrolytes were applied in electrochromic devices with polyaniline as the electrochromic layer. The PPC/LiClO4/BMIM(+)BF4(-)-based device exhibits much better electrochromic performance in terms of optical contrast and switching time due to the presence of much smaller cations.

  14. Interfacial Restructuring of Ionic Liquids Determined by Sum-Frequency Generation Spectroscopy and X-ray Reflectivity

    SciTech Connect

    Jeon, Yoonnam; Sung, Jaeho; Bu, Wei; Vaknin, David; Ouchi, Yukio; Kim, Doseok

    2009-01-16

    Surface sum-frequency generation spectroscopy and X-ray reflectivity were used to study the surface of [BMIM][X] ionic liquids (BMIM = 1-butyl-3-methylimidazolium cation, X = BF{sub 4}{sup -}, PF{sub 6}{sup -}, and I{sup -}). Sum-frequency signal strength from the terminal methyl groups of the cation at the surface indicates that the topmost surface of these ionic liquids is occupied by polar-oriented hydrophobic butyl chains having approximately 1/3 of the in-plane density of fully packed alkyl chains as observed by the same method for the hexadecanol Langmuir monolayer. X-ray reflectivity data reveal a layer with density larger than that of bulk. However, the reflectivity is not sufficiently sensitive to the exact location of this layer either at the vacuum interface or sandwiched between the bulk and the low-density alkyl chain, as observed in the sum-frequency measurements. Analysis of the reflectivity data in conjunction with the sum-frequency spectra strongly suggests the molecules forming the topmost layer are on average polar-oriented with their (loosely packed) butyl chains toward the gas/liquid interface, while the (densely packed) imidazolium cores/anions are in contact with the bulk liquid.

  15. Peculiarity of the liquid/vapour interface of an ionic liquid: study of surface tension and viscoelasticity of liquid BMImPF6 at various temperatures

    NASA Astrophysics Data System (ADS)

    Halka, V.; Tsekov, R.; Freyland, W.

    2005-03-01

    We have measured the surface tension and the capillary wave spectra at the liquid/vapour interface of the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate at various temperatures up to 400 K. From the weak temperature dependence of the surface tension a low value of the surface excess entropy of 3.5 × 10-5 J K-1 m-2 results which is consistent with a strongly aligned surface layer of imidazolium cations previously predicted by MD-calculations. The capillary wave spectra recorded at different wave numbers in the range 170 cm-1q 500 cm-1 exhibit strong deviations from the behaviour expected for the free surface of simple liquids. With an extended dispersion relation including the contributions of surface dipole moment density and shear surface excess viscosity - the spectra have been analyzed. It is found that - is negligibly small, whereas substantially influences the capillary wave spectra. The electrostatic potential across the interface, which corresponds to the measured dipole moment densities, qualitatively agrees with simulation calculations. The distinct temperature dependence of suggests that with increasing temperature an order-disorder transformation occurs in the surface layer.

  16. Photochemical synthesis of silver particles using water-in-ionic liquid microemulsions in high-pressure CO2.

    PubMed

    Harada, Masafumi; Kawasaki, Chika; Saijo, Kenji; Demizu, Masashi; Kimura, Yoshifumi

    2010-03-15

    Silver particles (Ag particles) were synthesized by the photoreduction of silver perchlorate (AgClO(4)) in water-in-ionic liquid (IL) microemulsions consisting of nonionic surfactant Tween 20, water, and ionic liquids, [1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF(4)]) or 1-octyl-3-methylimidazolium tetrafluoroborate ([OMIm][BF(4)])], mixed with a high-pressure (25 MPa) CO(2). The time evolution of the Ag particle formation by photoreduction was investigated by UV-Vis, cryo-TEM, extended X-ray absorption fine structure (EXAFS), and small-angle X-ray scattering (SAXS) measurements. In the particle formation process, aggregation and precipitation of Ag particles were suppressed under high-pressure CO(2). The average diameters of the metallic Ag particles prepared in water-in-[BMIm][BF(4)] and water-in-[OMIm][BF(4)] microemulsions were estimated from TEM to be 3.2 and 3.7 nm, respectively. SAXS analysis shows that the average diameters of the water droplets, which consisted of ionic precursors of AgClO(4) and Ag particles (or Ag aggregates), were estimated to be about 30-40 nm. In the process of Ag particle formation, the water droplet size under high-pressure CO(2) is more effectively regulated than that under ambient air, thereby preventing Ag particles from aggregating and precipitating.

  17. Ionic liquid assisted chemical strategy to TiO2 hollow nanocube assemblies with surface-fluorination and nitridation and high energy crystal facet exposure for enhanced photocatalysis.

    PubMed

    Yu, Shengli; Liu, Baocang; Wang, Qin; Gao, Yuxi; Shi, Ying; Feng, Xue; An, Xiaoting; Liu, Lixia; Zhang, Jun

    2014-07-09

    Realization of anionic nonmetal doping and high energy crystal facet exposure in TiO2 photocatalysts has been proven to be an effective approach for significantly improving their photocatalytic performance. A facile strategy of ionic liquid assisted etching chemistry by simply hydrothermally etching hollow TiO2 spheres composed of TiO2 nanoparticles with an ionic liquid of 1-butyl-3-methylimidazolium tetrafluoroborate without any other additives is developed to create highly active anatase TiO2 nanocubes and TiO2 nanocube assemblies. With this one-pot ionic liquid assisted etching process, the surface-fluorination and nitridation and high energy {001} crystal facets exposure can be readily realized simultaneously. Compared with the benchmark materials of P25 and TiO2 nanostructures with other hierarchical architectures of hollow spheres, flaky spheres, and spindles synthesized by hydrothermally etching hollow TiO2 spheres with nonionic liquid of NH4F, the TiO2 nanocubes and TiO2 nanocube assemblies used as efficient photocatalysts show super high photocatalytic activity for degradation of methylene blue, methyl orange, and rhodamine B, due to their surface-fluorination and nitridation and high energy crystal facet exposure. The ionic liquid assisted etching chemistry is facile and robust and may be a general strategy for synthesizing other metal oxides with high energy crystal facets and surface doping for improving photocatalytic activity.

  18. Studies on structural, thermal and AC conductivity scaling of PEO-LiPF6 polymer electrolyte with added ionic liquid [BMIMPF6

    NASA Astrophysics Data System (ADS)

    Chaurasia, S. K.; Saroj, A. L.; Shalu, Singh, V. K.; Tripathi, A. K.; Gupta, A. K.; Verma, Y. L.; Singh, R. K.

    2015-07-01

    Preparation and characterization of polymer electrolyte films of PEO+10wt.% LiPF6 + xwt.% BMIMPF6 (1-butyl-3-methylimidazolium hexafluorophosphate) containing dopant salt lithium hexafluorophosphate (LiPF6) and ionic liquid (BMIMPF6) having common anion PF6 - are reported. The ionic conductivity of the polymer electrolyte films has been found to increase with increasing concentration of BMIMPF6 in PEO+10 wt.% LiPF6 due to the plasticization effect of ionic liquid. DSC and XRD results show that the crystallinity of polymer electrolyte decreases with BMIMPF6 concentration which, in turn, is responsible for the increase in ionic conductivity. FTIR spectroscopic study shows the complexation of salt and/or ionic liquid cations with the polymer backbone. Ion dynamics behavior of PEO+LiPF6 as well as PEO+LiPF6 + BMIMPF6 polymer electrolytes was studied by frequency dependent conductivity, σ(f) measurements. The values σ(f) at various temperatures have been analyzed in terms of Jonscher power law (JPL) and scaled with respect to frequency which shows universal power law characteristics at all temperatures.

  19. J-aggregation of ionic liquid solutions of meso-tetrakis(4-sulfonatophenyl)porphyrin

    SciTech Connect

    Ali, Maroof; Kumar, Vinod; Baker, Sheila N; Baker, Gary A; Pandey, Siddharth

    2010-01-01

    The title porphyrin was dissolved in the hydrophilic ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate, [bmim][BF4], and triggered to assemble into J-aggregates by the addition of incremental volumes of water containing various amounts of acid (0.1, 0.2, or 1.0 M HCl). In contrast to recent studies, the current investigation is unique in that it centers on media that contain a predominant ionic liquid component (2.9 5.4 M [bmim][BF4]), as opposed to an aqueous electrolyte containing a small fraction of ionic liquid as dissociated solute. Complex aggregation and underlying photophysical behavior are revealed from absorption spectroscopy, steady-state fluorescence, and resonance light scattering studies. Upon addition of aqueous HCl, the efficient formation of H4TPPS2 J-aggregates from the diprotonated form of meso-tetrakis(4-sulfonatophenyl)porphyrin (H2TPPS4) occurs in [bmim][BF4]-rich media in a manner highly dependent upon the acidity, TPPS concentration, and solvent composition. The unique features of TPPS aggregation in this ionic liquid were elucidated, including the surprising disassembly of J-aggregates at higher aqueous contents, and our results are described qualitatively in terms of the molecular exciton theory. Finally, the potential of this system for the optical sensing of water at a sensitivity below 0.5 wt% is demonstrated. Overall, our findings accentuate how little is known about functional self-assembly within ionic liquids and suggest a number of avenues for exploring this completely untouched research landscape.

  20. A simple physical model for the simultaneous rationalisation of melting points and heat capacities of ionic liquids.

    PubMed

    Zvereva, Elena E; Katsyuba, Sergey A; Dyson, Paul J

    2010-11-07

    The analysis of potential energy surfaces of ion pairs within the framework of an anharmonic oscillator model allows rationalization and prediction of melting points (T(mp)) and heat capacities (C(p)) of ionic liquids (ILs) comprising di- and trialkylimidazolium or tetraalkylphosphonium cations and weakly coordinating BF(4), PF(6), or Tf(2)N anions. Multiple short contacts between the counterions are demonstrated to be typical for the imidazolium based ILs. Differences in the types of contacts result in moderate changes of melting points of the ILs, comparable with differences in T(mp) experimentally determined for the same crystal. The theoretical evaluation of IL heat capacities additionally requires a consideration of conformational behaviour of the corresponding cations. A similar conformational composition of 1-butyl-3-methylimidazolium hexafluorophosphate and tetrafluoroborate at ambient temperature is demonstrated by the combined DFT-vibrational spectroscopy approach. A rough proportionality of C(p) to 1/T(mp) of ionic liquids is suggested, provided that the conformational composition of the ILs does not change on crystal-to-liquid transition.

  1. Phase-transfer behavior of cross-linked poly(acrylic acid) particles prepared by dispersion polymerization from ionic liquid to water.

    PubMed

    Minami, Hideto; Mizuta, Yusuke; Kimura, Akira

    2012-02-07

    The phase-transfer behavior of poly(acrylic acid) (PAA) particles from the hydrophobic ionic liquid N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(trifluoromethanesulfonyl)amide phase to the water phase in the particle state, which we reported previously, was examined in more detail. PAA particles were prepared in the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide ([Bmim][TFSA]) and the organic solvent chloroform and were extracted. The transfer of PAA particles to water in the particle state was also observed in [Bmim][TFSA] systems. In contrast, the transfer phenomenon was not observed in the chloroform system. It was clarified that water/oil interfacial tension γ(wo) is an important parameter in the extraction of PAA in the particle state from the viewpoint of free energy. When the cationic surfactant tetradecyltrimethylammonium bromide, aqueous solution was used as the extraction medium, the PAA particles were extracted in the particle state from chloroform to water, in which γ(wo) became as low as that of the ionic liquid. This suggests that the phase-transfer phenomenon of PAA particles in the particle state was induced by the ionic liquid's unique property of low interfacial tension with water despite its high hydrophobic character.

  2. Role of LiBF4 in Ionic Liquid Membranes for Facilitated CO2 Transport.

    PubMed

    Choi, Yeji; Hong, Gil Hwan; Kang, Sang Wook

    2016-03-01

    The ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM BF4)/LiBF4 electrolyte was prepared for highly selective facilitated CO2 transport membranes. When LiBF4 was incorporated into BMIM BF4, synergy effects by free Li+ ion and imidazolium cations is expected to enhance the separation performance for CO2/N2 and CO2/CH4. The free state of BF4- ions in BMIM BF4/LiBF4 solutions was investigated by FT-Raman spectroscopy. For the coordination of LiBF4 with BMIMBF4, thermal gravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) was utilized. Electrolyte membranes consisting of BMIM BF4 and LiBF4 showed selectivities of 8.40 and 8.25 for CO2/N2 and CO2/CH4, respectively. Neat BMIM BF4 membrane showed selectivities of 5.0 and 4.8, respectively. Enhanced separation performance was attributed to increased free Li+ and abundant free imidazolium cations.

  3. Temperature-dependent formation and transformation of mesostructures in water-ionic liquid mixtures.

    PubMed

    Kattnig, Daniel R; Hinderberger, Dariush

    2012-05-01

    The temperature-dependent formation and transformation of mesostructures in binary mixtures of the ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim(+)][BF(4)(-)]) and water are characterized. Through addition of nitroxide radicals as paramagnetic spin probes, the temperature dependence of the solution structure can be assessed by using electron paramagnetic resonance (EPR) spectroscopy from typical solutes' points of view. Additionally, the phase behavior on cooling and reheating is probed by differential scanning calorimetry (DSC). Thermal hysteresis and memory effects are observed, and DSC is used to identify the crystallization and thawing of ice as the pertinent phase transition. The EPR data of the nitroxide radicals before and after freezing and thawing reveal a transformation of the mesostructures, probably triggered by the crystallization of water pools to ice. A more polar state results after thawing, thereby suggesting a rupture and dissolution of the ordered IL-rich mesostructures. If the thawed solutions are not agitated, the system relaxes very slowly, that is, at room temperature with a time constant of approximately 90 h, to its equilibrium state of mesophase-separated IL-rich and bulk-like water regions. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Enhanced Horizontal Transfer of Antibiotic Resistance Genes in Freshwater Microcosms Induced by an Ionic Liquid

    PubMed Central

    Wang, Qing; Mao, Daqing; Mu, Quanhua; Luo, Yi

    2015-01-01

    The spread and propagation of antibiotic resistance genes (ARGs) is a worldwide public health concern. Ionic liquids (ILs), considered as “environmentally friendly” replacements for industrial organic solvents, have been widely applied in modern industry. However, few data have been collected regarding the potential ecological and environmental risks of ILs, which are important for preparing for their potential discharge into the environment. In this paper, the IL 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIm][PF6]) (0.001-5.0 g/L) was tested for its effects on facilitating ARGs horizontal transfer mediated by plasmid RP4 in freshwater microcosms. In the horizontal transfer microcosms, the transfer frequency of plasmid RP4 was significantly enhanced (60-fold higher than untreated groups) by the IL [BMIm][PF6] (1.0 g/L). Meanwhile, two strains of opportunistic pathogen Acinetobacter spp. and Salmonella spp. were isolated among the transconjugants, illustrating plasmid RP4 mediated horizontal transfer of ARGs occurred in pathogen. This could increase the risk of ARGs dissemination to human pathogens and pose great threat to public health. The cause that [BMIm[PF6] enhanced the transfer frequency of plasmid RP4 was proposed by suppressed cell membrane barrier and enhanced cell membrane permeability, which was evidenced by flow cytometry (FCM). This is the first report that some ILs facilitate horizontal transfer of plasmid RP4 which is widely distributed in the environment and thus add the adverse effects of the environmental risk of ILs. PMID:25951456

  5. Acute toxicity of ionic liquids for three freshwater organisms: Pseudokirchneriella subcapitata, Daphnia magna and Danio rerio.

    PubMed

    Pretti, Carlo; Chiappe, Cinzia; Baldetti, Ilaria; Brunini, Sara; Monni, Gianfranca; Intorre, Luigi

    2009-05-01

    The static acute toxicities of 18 ionic liquids (ILs) were determined for three representative freshwater organisms, the cladoceran Daphnia magna, the green alga Pseudokirchneriella subcapitata (formerly known as Selenastrum capricornutum), and the fish Danio rerio (formerly known as zebrafish). The test kit compounds contained three widely used ILs (1-butyl-3-methylimidazolium bis(triflimide), [bmim][Tf(2)N], butylpyridinium bis(triflimide), [bpy][Tf(2)N], and N,N-methylbutylpyrrolidinium bis(triflimide), [bmpyrr][Tf(2)N]) and 15 less common salts. These latter comprised a range of five anions, four positively charged head groups (ammonium, morpholinium, thiophenium, and sulfonium), five 1-methyl-3-alkyl imidazolium derivatives bearing a specific functional group on the longer alkyl chain (Cl, OH, or (CH(3))(3)Si) and three imidazolium derivatives characterized by the presence of a hydrogen atom on the imidazolium nitrogen ("Brønsted acidic imidazolium"-based ILs). Generally, long-chain ammonium salts showed higher toxicity to algae, cladocerans, and fish, whereas very low toxicities characterized sulfonium- and morpholinium-based ILs. In imidazolium-based ILs, the substitution of one or two carbon atoms of the longer alkyl chain with a more electronegative atom (chlorine or oxygen) reduced the acute toxicity for algae and cladocerans. Low toxicity also characterized the "Brønsted acidic imidazolium"-based ILs. Structural information for a rational designer of safer ILs can be obtained from these studies.

  6. Effects of Room-Temperature Ionic Liquids on Zebra Mussels (Dreissena polymorpha)

    NASA Astrophysics Data System (ADS)

    Costello, D. M.; Bernot, R. J.; Lamberti, G. A.

    2005-05-01

    Zebra mussels (Dreissena polymorpha) are exotic bivalves that are widely distributed in eastern North America. We propose that this nuisance organism could serve as a model species for studies of aquatic toxicology. We tested zebra mussels response to room-temperature ionic liquids (ILs), which are being synthesized as environmentally friendly alternatives to volatile organic solvents. Volatile organic solvents contribute to atmospheric pollution and ozone depletion, whereas ILs are non-volatile and less harmful to the atmosphere. Although ILs would contribute significantly less to air pollution, little is known about their potential effects on aquatic ecosystems. In 72-hour toxicity tests, we determined the acute effects of three imidazolium-based ILs (1-butyl-3-methylimidazolium bromide (bmimBr), 1-hexyl-3-methylimidazolium bromide (hmimBr), and 1-octyl-3-methylimidazolium bromide (omimBr)) on the survival of zebra mussels. As alkyl chain length decreased, median lethal concentration (LC50) decreased from 1291 mg L-1 for bmimBr, to 105 mg L-1 for hmimBr, and 21.2 mg L-1 for omimBr. For bivalve mussels, the toxicities of these ILs are comparable to the toxicities of commonly used industrial solvents (e.g., toluene, benzene). This study presents a foundation for using zebra mussels in toxicity studies as well as possible models for less common Unionid mussels.

  7. Complexation of chitosan with surfactant like ionic liquids: molecular interactions and preparation of chitosan nanoparticles.

    PubMed

    Bharmoria, Pankaj; Singh, Tejwant; Kumar, Arvind

    2013-10-01

    Interactions and behavior of chitosan (Ch) with surface active ionic liquids (ILs)- 1-butyl-3-methylimidazolium octylsulfate, [C4mim][C8OSO3] or 3-methyl-1-octylimidazolium chloride, [C8mim][Cl]-have been probed at the air solution interface and in the bulk in aqueous media at pH 3.0 using a multi-technique approach, viz. tensiometry, conductometry, turbidimetry, dynamic light scattering (DLS), and atomic force microscopy (AFM). At the interface, a strong complexation is observed in Ch-[C4mim][C8OSO3] system. Bulk [C4mim][C8OSO3] interacts with Ch to form Ch-[C4mim][C8OSO3] complexes which precipitate out at higher IL concentrations, whereas comparatively weaker Ch-[C8mim][Cl] complexes remain solubilized in the solution. DLS measurements showed that the Ch chains contract before the cmc and expands after the cmc upon interaction with both the ILs. Interaction of ILs with Ch resulted in facile preparation of uniformly distributed Ch nanoparticles with good sphericity and control which have been verified using DLS, SEM, AFM, and fluorescence microscopy. The present study provides an understanding of forces governing the complexation behavior of Ch with surface active ILs and their efficacy to produce Ch nanoparticles. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. Decomposition of Imidazolium-Based Ionic Liquids in Contact with Lithium Metal.

    PubMed

    Schmitz, Paulo; Jakelski, Rene; Pyschik, Marcelina; Jalkanen, Kirsi; Nowak, Sascha; Winter, Martin; Bieker, Peter

    2017-03-09

    Ionic liquids (ILs) are considered to be suitable electrolyte components for lithium-metal batteries. Imidazolium cation based ILs were previously found to be applicable for battery systems with a lithium-metal negative electrode. However, herein it is shown that, in contrast to the well-known IL N-butyl-N-methylpyrrolidinium bis[(trifluoromethyl)sulfonyl]imide ([Pyr14 ][TFSI]), 1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([C2MIm][TFSI]) and 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([C4MIm][TFSI]) are chemically unstable versus metallic lithium. A lithium-metal sheet was immersed in pure imidazolium-based IL samples and aged at 60 °C for 28 days. Afterwards, the aged IL samples were investigated to deduce possible decomposition products of the imidazolium cation. The chemical instability of the ILs in contact with lithium metal and a possible decomposition starting point are shown for the first time. Furthermore, the investigated imidazolium-based ILs can be utilized for lithium-metal batteries through the addition of the solid-electrolyte interphase (SEI) film-forming additive fluoroethylene carbonate. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Organic solvents induce the formation of oil-in-ionic liquid microemulsion aggregations.

    PubMed

    Gao, Yanan; Li, Na; Zhang, Shaohua; Zheng, Liqiang; Li, Xinwei; Dong, Bin; Yu, Li

    2009-02-05

    The role of four organic solvents in the formation process of 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF4) based ionic liquid (IL) microemulsions is investigated. The results showed that the addition of Triton X-100 remarkably decreased the conductivity of bmimBF4. The added organic solvents provided a strong apolar environment for the hydrophobic tails of Triton X-100 and caused the surfactant molecules to aggregate into the interfacial film of oil-in-bmimBF4 (O/IL) microemulsions. As a result, the conductivities of the solutions were initially increased because the insulative Triton X-100 molecules were assembled, which corresponded to increasing the concentration of continuous bmimBF4 solutions. The hydrophobic interaction between the dispersed organic solvents and the hydrophobic tails of Triton X-100 may be the driving force for the formation of O/IL microemulsions. The droplets of O/IL microemulsions were successively swollen by organic solvents, and a bicontinuous IL-containing microemulsion was observed by freeze-fracture transmission electron microscopy for the first time. The current study can help in further understanding the ILs-containing microemulsions and thereby improve microemulsion theory.

  10. Evidence of water-in-ionic liquid microemulsion formation by nonionic surfactant Brij-35.

    PubMed

    Rai, Rewa; Pandey, Siddharth

    2014-09-02

    Brij-35, a common and popular nonionic surfactant, is shown to form water-in-ionic liquid (w/IL) microemulsions with IL 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) as the bulk phase. The presence of w/[bmim][PF6] microemulsions is hinted by the significantly increased solubility of water in Brij-35 solution of [bmim][PF6]. The formation of w/[bmim][PF6] microemulsions by Brij-35 is confirmed using dynamic light scattering (DLS) and small-angle X-ray scattering (SAXS) measurements. Brij-35 forms reverse micelle-type aggregates within [bmim][PF6] in the absence of added-water. These reverse micelles become w/[bmim][PF6] microemulsions as the water is added to the system. As the water loading (w0) is increased, the average diameter of the aggregates increases. Fourier transform infrared (FTIR) absorbance data reveal the presence of both "bound" and "free" water within the system. The "bound" water is associated with the water pools of the w/[bmim][PF6] microemulsions. Excited-state proton transfer (ESPT) involving probe pyranine shows deprotonation of pyranine within the water pools of the w/[bmim][PF6] microemulsions.

  11. Dielectric analysis of micelles and microemulsions formed in a hydrophilic ionic liquid. I. Interaction and percolation.

    PubMed

    Lian, Yiwei; Zhao, Kongshuang

    2011-10-06

    Dielectric measurements were carried out on binary mixtures of Triton X-100 (TX-100, a nonionic surfactant with a polyoxyethylene chain) and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF(4)], a hydrophilic ionic liquid), and [bmim][BF(4)]/TX-100/cyclohexane microemulsions in a wide frequency range to study the molecular interaction and percolation in these systems. Striking dielectric relaxations were observed, and the dc conductivity data were obtained from the measured total dielectric loss spectra. The interaction between TX-100 and [bmim][BF(4)] is estimated by analyzing the dc conductivity of TX-100/[bmim][BF(4)] solutions in light of the Bruggeman's effective medium approximation, which indicates that spherical micelles are formed when the TX-100 volume fraction is below 48% and the number of cations associated with every TX-100 molecule is eight. For IL-oil microemulsions, both the dependence of dc conductivity and the permittivity (for fixed frequency) on cyclohexane concentration were used to identify the oil-in-IL, bicontinuous, and IL-in-oil microregions. Both the conduction and dielectric relaxation behavior suggest that a static percolation occurs in this hydrophilic IL microemulsion.

  12. Temperature-induced microstructural changes in ionic liquid-based microemulsions.

    PubMed

    Gao, Yanan; Li, Na; Hilfert, Liane; Zhang, Shaohua; Zheng, Liqiang; Yu, Li

    2009-02-03

    In the present contribution, results concerning the effect of temperature on the nonionic surfactant Triton X-100 based 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF4)-in-cyclohexane and bmimBF4-in-toluene ionic liquid (IL) reverse microemulsions are reported. Dynamic light scattering (DLS) along with freeze-fracture transmission electron microscopy (FF-TEM) measurements revealed that the sizes of single microemulsion droplets increased with increasing temperature. However, a decreased temperature led to the appearance of droplet clusters, which have also been observed previously when the single microemulsion droplets were swollen by added bmimBF4 to a certain extent (Gao, Y. A.; Vogit, A.; Hilfert, L.; Sundmacher, K. ChemPhysChem, 2008, 9, 1603-1609). Compared to traditional aqueous microemulsions, IL microemulsions revealed relatively high temperature-independence. The droplet-shaped microstructure was always kept in a large range of temperature. The temperature-independence is ascribed to the temperature-insensitive electrostatic attraction between the solubilized bmimBF4 and Triton X-100, which was considered to be the driving force for solubilizing bmimBF4 into the cores of Triton X-100 aggregates. Two-dimensional rotating frame nuclear Overhauser effect (NOE) experiments (ROESY) further confirmed the microstructural change with temperature.

  13. Role of the surfactant structure in the behavior of hydrophobic ionic liquids within aqueous micellar solutions.

    PubMed

    Behera, Kamalakanta; Kumar, Vinod; Pandey, Siddharth

    2010-04-06

    The behavior of an ionic liquid (IL) within aqueous micellar solutions is governed by its unique property to act as both an electrolyte and a cosolvent. The influence of the surfactant structure on the properties of aqueous micellar solutions of zwitterionic SB-12, nonionic Brij-35 and TX-100, and anionic sodium dodecyl sulfate (SDS) in the presence of the "hydrophobic" IL 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF(6)]) is assessed along with the possibility of forming oil-in-water microemulsions in which the IL acts as the "oil" phase. The solubility of [bmim][PF(6)] within aqueous micellar solutions increases with increasing surfactant concentration. In contrast to anionic SDS, the zwitterionic and nonionic surfactant solutions solubilize more [bmim][PF(6)] at higher concentrations and the average aggregate size remains almost unchanged. The formation of IL-in-water microemulsions when the concentration of [bmim][PF(6)] is above its aqueous solubility is suggested for nonionic Brij-35 and TX-100 aqueous surfactant solutions.

  14. Investigation of the interaction of pepsin with ionic liquids by using fluorescence spectroscopy.

    PubMed

    Fan, Yunchang; Zhang, Sheli; Wang, Qiang; Li, Junhai; Fan, Haotian; Shan, Dongkai

    2013-06-01

    The molecular mechanism of the interaction between pepsin and two typical ionic liquids (ILs), 1-butyl-3-methylimidazolium chloride ([C4mim]Cl) and 1-octyl-3-methylimidazolium chloride ([C8mim]Cl), was investigated with fluorescence spectroscopy, ultraviolet absorption, and circular dichroism spectroscopy at a pH value of 1.6. The results suggest that ILs could quench the intrinsic fluorescence of pepsin, probably via a dynamic quenching mechanism. The fluorescence quenching constants were determined by employing the classic Stern-Volmer equation. The constant values are very small, indicating that only a very weak interaction between ILs and pepsin exists. The Gibbs free-energy change, enthalpy change (ΔH), and entropy change (ΔS) during the interaction of pepsin and ILs were estimated. Positive values of ΔH and ΔS indicate that the interaction between ILs and pepsin is mainly driven by hydrophobic interaction. Synchronous and three-dimensional fluorescence spectra demonstrate that the addition of ILs (0-0.20 mol L(-1) for each IL) does not bring apparent changes to the microenvironments of tyrosine and tryptophan residues. Activity experiments show that the activity of pepsin is concentration dependent; higher concentrations of ILs (>0.22 mol L(-1) for [C8mim]Cl and >0.30 mol L(-1) for [C4mim]Cl) cause the remarkable reduction of enzyme activity. The presence of ILs also does not improve the thermal stability of pepsin.

  15. Pretreatment of corn stover by combining ionic liquid dissolution with alkali extraction.

    PubMed

    Geng, Xinglian; Henderson, Wesley A

    2012-01-01

    Pretreatment plays an important role in the efficient enzymatic hydrolysis of biomass into fermentable sugars for biofuels. A highly effective pretreatment method is reported for corn stover which combines mild alkali-extraction followed by ionic liquid (IL) dissolution of the polysaccharides and regeneration (recovery of the polysaccharides as solids). Air-dried, knife-milled corn stover was soaked in 1% NaOH at a moderate condition (90°C, 1 h) and then thoroughly washed with hot deionized (DI) water. The alkali extraction solublized 75% of the lignin and 37% of the hemicellulose. The corn stover fibers became softer and smoother after the alkali extraction. Unextracted and extracted corn stover samples were separately dissolved in an IL, 1-butyl-3-methylimidazolium chloride (C(4) mimCl), at 130°C for 2 h and then regenerated with DI water. The IL dissolution process did not significantly change the chemical composition of the materials, but did alter their structural features. Untreated and treated corn stover samples were hydrolyzed with commercial enzyme preparations including cellulases and hemicellulases at 50°C. The glucose yield from the corn stover sample that was both alkali-extracted and IL-dissolved was 96% in 5 h of hydrolysis. This is a highly effective methodology for minimizing the enzymatic loading for biomass hydrolysis and/or maximizing the conversion of biomass polysaccharides into sugars. Copyright © 2011 Wiley Periodicals, Inc.

  16. Hydrothermal microwave valorization of eucalyptus using acidic ionic liquid as catalyst toward a green biorefinery scenario.

    PubMed

    Xu, Ji-Kun; Chen, Jing-Huan; Sun, Run-Cang

    2015-10-01

    The application of the acidic ionic liquid (IL), 1-butyl-3-methylimidazolium hydrogensulfate ([bmim]HSO4), as a catalyst in the hydrothermal microwave treatment (HMT) and green upgradation of eucalyptus biomass has been investigated. The process was carried out in a microwave reactor system at different temperatures (140-200°C) and evaluated for severities. The xylooligosaccharides (XOS, refers to a DP of 2-6) yield up to 5.04% (w/w) of the initial biomass and 26.72% (w/w) of xylan were achieved. Higher temperature resulted in lower molecular weight product, and enhanced the concentration of monosaccharides and byproducts. The morphology and structure of the solid residues were performed using an array of techniques, such as SEM, XRD, FTIR, BET surface area, and CP/MAS (13)C NMR, by which the increase of crystallinity, the destruction of surface structure, and the changes in functional groups and compositions were studied after the pretreatment, thus significantly enhancing the enzymatic hydrolysis.

  17. Development of Bitter Taste Sensor Using Ionic-Liquid/Polymer Membranes

    NASA Astrophysics Data System (ADS)

    Akutagawa, Nobuyuki; Toida, Jinichi; Amano, Yoshihiko; Ikezaki, Hidekazu; Toko, Kiyoshi; Arikawa, Yukihiko

    A taste sensor is composed of several kinds of lipid/polymer membranes as transducers which convert taste information to electric signal. Thus, the role of membranes is very important to detect various taste components. In this paper, we developed novel membranes which specifically respond to quinine that is typical bitter substances. These membranes were composed of hydrophobic ionic liquid such as N, N, N-trimethyl-N-propylammonium bis(trifluoromethansulfonyl)imide, 1-butyl-3-methylimidazolium hexafluorophosphate and 1-butylpyridinium hexafluorophosphate, a plasticizer, 2-nitrophenyl octyl ether and a polymer, polyvinyl chloride. In addition to quinine, they also showed response to both several kinds of alkaloids such as caffeine and strychnine, and non-alkaloid such as phenylthiocarbamide. The order of these responses was equal to that of the tongue glossopharyngeal nerve of flog. Furthermore, there were the other alkaloids which response to these membranes. Especially in these alkaloids, they showed high response to denatonium benzoate and berberin chloride which have a strong bitter taste.

  18. Esterification of potato starch by a biocatalysed reaction in an ionic liquid.

    PubMed

    Zarski, Arkadiusz; Ptak, Sylwia; Siemion, Przemyslaw; Kapusniak, Janusz

    2016-02-10

    In this study, potato starch was esterified with oleic acid, using 1-butyl-3-methylimidazolium chloride as a reaction medium and an immobilised lipase from Thermomyces lanuginosus as a catalyst. The degree of substitution (DS) of the products was determined by the volumetric method; and the best esterified product (with the highest DS) was determined by an elemental analysis. The effect of the reaction parameters on the DS, such as the time and the temperature, were also studied. The product with the highest DS (0.22) was found in the reaction carried out at 60 °C for 4h. Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) analyses confirmed the esterification of the potato starch. Furthermore, the results of X-ray diffraction (XRD) and a scanning electron microscopy (SEM) revealed that the crystallinity and the morphology of the native potato starch was slightly changed during its partial gelatinisation in the ionic liquid, and was completely destroyed as a result of the formation of the esters. The thermal stability of the starch oleate decreased, when compared to the unmodified starch, as was indicated by a thermal gravimetric analysis (TGA).

  19. Pretreatment of eucalyptus with recycled ionic liquids for low-cost biorefinery.

    PubMed

    Xu, Jikun; Liu, Bingchuan; Hou, Huijie; Hu, Jingping

    2017-06-01

    It is urgent to develop recycled ionic liquids (ILs) as green solvents for sustainable biomass pretreatment. The goal of this study is to explore the availability and performance of reusing 1-allyl-3-methylimidazolium chloride ([amim]Cl) and 1-butyl-3-methylimidazolium acetate ([bmim]OAc) for pretreatment, structural evolution, and enzymatic hydrolysis of eucalyptus. Cellulose enzymatic digestibility slightly decreased with the increased number of pretreatment recycles. The hydrolysis efficiencies of eucalyptus pretreated via 4th recycled ILs were 54.3% for [amim]Cl and 72.8% for [bmim]OAc, which were 5.0 and 6.7-folds higher than that of untreated eucalyptus. Deteriorations of ILs were observed by the relatively lower sugar conversion and lignin removal from eucalyptus after 4th reuse. No appreciable changes in fundamental framework and thermal stability of [amim]Cl were observed even after successive pretreatments, whereas the anionic structure of [bmim]OAc was destroyed or replaced. This study suggested that the biomass pretreatment with recycled ILs was a potential alternative for low-cost biorefinery. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Elucidation of the effect of ionic liquid pretreatment on rice husk via structural analyses

    PubMed Central

    2012-01-01

    Background In the present study, three ionic liquids, namely 1-butyl-3-methylimidazolium chloride ([BMIM]Cl), 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc), and 1-ethyl-3-methylimidazolium diethyl phosphate ([EMIM]DEP), were used to partially dissolve rice husk, after which the cellulose were regenerated by the addition of water. The aim of the investigation is to examine the implications of the ionic liquid pretreatments on rice husk composition and structure. Results From the attenuated total reflectance Fourier transform-infrared (ATR FT-IR) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM) results, the regenerated cellulose were more amorphous, less crystalline, and possessed higher structural disruption compared with untreated rice husk. The major component of regenerated cellulose from [BMIM]Cl and [EMIM]DEP pretreatments was cellulose-rich material, while cellulose regenerated from [EMIM]OAc was a matrix of cellulose and lignin. Cellulose regenerated from ionic pretreatments could be saccharified via enzymatic hydrolysis, and resulted in relatively high reducing sugars yields, whereas enzymatic hydrolysis of untreated rice husk did not yield reducing sugars. Rice husk residues generated from the ionic liquid pretreatments had similar chemical composition and amorphousity to that of untreated rice husk, but with varying extent of surface disruption and swelling. Conclusions The structural architecture of the regenerated cellulose and rice husk residues showed that they could be used for subsequent fermentation or derivation of cellulosic compounds. Therefore, ionic liquid pretreatment is an alternative in the pretreatment of lignocellulosic biomass in addition to the conventional chemical pretreatments. PMID:22958710

  1. Solubility of alkali metal halides in the ionic liquid [C4C1im][OTf].

    PubMed

    Kuzmina, O; Bordes, E; Schmauck, J; Hunt, P A; Hallett, J P; Welton, T

    2016-06-28

    The solubilities of the metal halides LiF, LiCl, LiBr, LiI, NaF, NaCl, NaBr, NaI, KF, KCl, KBr, KI, RbCl, CsCl, CsI, were measured at temperatures ranging from 298.15 to 378.15 K in the ionic liquid 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([C4C1im][OTf]). Li(+), Na(+) and K(+) salts with anions matching the ionic liquid have also been investigated to determine how well these cations dissolve in [C4C1im][OTf]. This study compares the influence of metal cation and halide anion on the solubility of salts within this ionic liquid. The highest solubility found was for iodide salts, and the lowest solubility for the three fluoride salts. There is no outstanding difference in the solubility of salts with matching anions in comparison to halide salts. The experimental data were correlated employing several phase equilibria models, including ideal mixtures, van't Hoff, the λh (Buchowski) equation, the modified Apelblat equation, and the non-random two-liquid model (NRTL). It was found that the van't Hoff model gave the best correlation results. On the basis of the experimental data the thermodynamic dissolution parameters (ΔH, ΔS, and ΔG) were determined for the studied systems together with computed gas phase metathesis parameters. Dissolution depends on the energy difference between enthalpies of fusion and dissolution of the solute salt. This demonstrates that overcoming the lattice energy of the solid matrix is the key to the solubility of inorganic salts in ionic liquids.

  2. Radiation effects on hydrophobic ionic liquid [C4mim][NTf2] during extraction of strontium ions.

    PubMed

    Yuan, Liyong; Peng, Jing; Xu, Ling; Zhai, Maolin; Li, Jiuqiang; Wei, Genshuan

    2009-07-02

    The applications of room-temperature ionic liquids (RTILs) in separation of high level radioactive nuclides demand a comprehensive knowledge of the stability and metal ion extraction of RTILs under radiation. Herein, we assessed the influence of gamma-irradiation on the [C(4)mim][NTf(2)]-based extraction system, where [C(4)mim](+) is 1-butyl-3-methylimidazolium and [NTf(2)](-) is bis(trifluoromethylsulfonyl)imide, by solvent extraction of Sr(2+) using irradiated [C(4)mim][NTf(2)] in combination with dicyclohexyl-18-crown-6 (DCH18C6). It was found that the degree of extraction for Sr(2+) from water to irradiated [C(4)mim][NTf(2)] decreased compared with that to unirradiated [C(4)mim][NTf(2)], and the decrement enhanced obviously with increasing dose. NMR spectroscopic probe analysis revealed the formation of acids during irradiation of [C(4)mim][NTf(2)]. The decrease of Sr(2+) partitioning in irradiated [C(4)mim][NTf(2)] is attributed to the competition between H(+) with Sr(2+) to interact with DCH18C6. Accordingly, washing irradiated [C(4)mim][NTf(2)] with water gives a simple way of ionic liquid recycling. Furthermore, the degree of extraction for Sr(2+) from 3 mol.L(-1) nitric acid solution to [C(4)mim][NTf(2)] is independent of the irradiation of [C(4)mim][NTf(2)] since the amount of the radiation-generated H(+) is negligible in such a high acidic solution.

  3. A paradoxical method for NAD+/NADH accumulation on an electrode surface using a hydrophobic ionic liquid.

    PubMed

    Masuda, Miyuki; Motoyama, Yusuke; Kuwahara, Jun; Nakamura, Nobuhumi; Ohno, Hiroyuki

    2013-01-15

    In this communication, we describe a novel and facile method for the immobilization of NAD(+)/NADH on an electrode surface using a hydrophobic ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C4mim][Tf(2)N]). By taking advantage of the insolubility of NAD(+)/NADH in hydrophobic ionic liquids, it is expected that NAD(+)/NADH can be retained on the electrode's surface. Alcohol dehydrogenase (ADH) and NAD(+)/NADH were immobilized with a gelatin hydrogel on an electrode that was modified with an electropolymerized ruthenium complex containing 5-amino-1,10-phenanthroline (pAPRu) as a mediator for NADH oxidation. The (ADH, NAD(+))/pAPRu-immobilized electrode exhibited the electrocatalytic oxidation of ethanol in [C4mim][Tf(2)N]. The obtained catalytic current in [C4mim][Tf(2)N] was comparable to that in buffer solution containing NAD(+). It was confirmed by UV-vis spectroscopy that NAD(+) did not dissolve in the [C4mim][Tf(2)N] and was retained on the electrode's surface. Furthermore, we succeeded in constructing an ethanol/O(2) biofuel cell comprised of an (ADH, NAD(+))/pAPRu anode and a bilirubin oxidase cathode using [C4mim][Tf(2)N] as an electrolyte.

  4. Green synthesis of polymer monoliths incorporated with carbon nanotubes in room temperature ionic liquid and deep eutectic solvents.

    PubMed

    Zhang, Li-Shun; Gao, Shu-Ping; Huang, Yan-Ping; Liu, Zhao-Sheng

    2016-07-01

    In this work, an efficient method to prepare polymer monoliths with incorporated carbon nanotubes in a mixture of room temperature ionic liquid and deep eutectic solvents was developed. With assistance of the binary green solvent, 1-butyl-3-methylimidazolium tetrafluoroborate and choline chloride/ethylene glycol, single-walled carbon nanotubes were dispersed successfully in pre-polymerization mixture without need of oxidative cutting of carbon nanotubes, which may allow depletion of the emission of volatile organic compounds into environment. The novel single-walled carbon nanotubes monolith was evaluated by capillary electrochromatography. Compared with the monolith made without single-walled carbon nanotubes, the monolith with the incorporation of single-walled carbon nanotubes exhibited high column efficiency (251,000plates/m) in the chromatographic separation. The morphology of the monolith can be tuned by the composition of mixture of ionic liquids and deep eutectic solvents to afford good column permeability and excellent separation ability for small molecules of alkyl phenones and alkyl benzenes. The results demonstrated that the method is a green strategy for the fabrication of multifunctional polymer monoliths. Copyright © 2016. Published by Elsevier B.V.

  5. Synthesis, COSMO-RS analysis and optical properties of surface modified ZnS quantum dots using ionic liquids

    NASA Astrophysics Data System (ADS)

    Shahid, Robina; Muhammad, Nawshad; Gonfa, Girma; Toprak, Muhammet S.; Muhammed, Mamoun

    2015-10-01

    Zinc sulfide (ZnS) quantum dots (QDs) were synthesized using the microwave assisted ionic liquid (MAIL) route. Three ionic liquids (ILs), namely, 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF4]), trihexyl(tetradecyl) phosphonium bis(trifluoromethanesulfonyl) amide ([P6,6,6,14][TSFA]) and trihexyl(tetradecyl) phosphonium chloride ([P6,6,6,14][Cl]) were used in this study. The size and structure of the QDs were characterized by high-resolution transmission electron microscopy (HR-TEM) and selected area electron diffraction (SAED) pattern, respectively. The synthesized QDs were of wurtzite crystalline structure with size less than 5 nm. The QDs were more uniformly distributed while using the phosponium based ILs as a reaction medium during synthesis. The optical properties were investigated by UV-vis absorption and photoluminescence (PL) emission spectroscopy. The optical properties of QDs showed the quantum confinement effect in their absorption and the effect of cation and anion structural moiety was observed on their bandedge emission. The QDs emission intensity was measured higher for [P6,6,6,14][Cl] due to their better dispersion as well as high charge density of Cl anion. The capability of the ILs in stabilizing the QDs was interpreted by density functional theory (DFT) computations. The obtained results are in good agreement with the theoretical prediction.

  6. Investigation of Dynamics in BMIM TFSA Ionic Liquid through Variable Temperature and Pressure NMR Relaxometry and Diffusometry

    DOE PAGES

    Pilar, Kartik; Rua, Armando; Suarez, Sophia N.; ...

    2017-05-11

    A comprehensive variable temperature, pressure and frequency multinuclear (1H, 2H, and 19F) magnetic resonance study was undertaken on selectively deuterated 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide (BMIM TFSA) ionic liquid isotopologues. This study builds on our earlier investigation of the effects of increasing alkyl chain length on diffusion and dynamics in imidazolium-based TFSA ionic liquids. Fast field cycling 1H T1 data revealed multiple modes of motion. Through calculation of diffusion coefficient (D) values and activation energies, the low- and high-field regimes were assigned to the translational and reorientation dynamics respectively. Variable-pressure 2H T1 measurements reveal site-dependent interactions in the cation with strengths in themore » order MD3 > CD3 > CD2, indicating dissimilarities in the electric field gradients along the alkyl chain, with the CD2 sites having the largest gradient. Additionally, the α saturation effect in T1 vs. P was observed for all three sites, suggesting significant reduction of the short-range rapid reorientational dynamics. This reduction was also deduced from the variable pressure 1H T1 data, which showed an approach to saturation for both the methyl and butyl group terminal methyl sites. Pressure-dependent D measurements show independent motions for both cations and anions, with the cations having greater D values over the entire pressure range.« less

  7. Transport properties of aqueous ionic liquid microemulsions: influence of the anion type and presence of the cosurfactant.

    PubMed

    Piekart, Jakub; Łuczak, Justyna

    2015-12-14

    Transport properties, viz. specific conductivity, dynamic viscosity and apparent diffusion coefficients, were measured as a function of water content in aqueous ionic liquid microemulsions containing 1-butyl-3-methylimidazolium hexafluorophosphate, [BMIM][PF6] and bis(trifluoromethanesulphonyl)imide, [BMIM][Tf2N], stabilized by the nonionic surfactant TX-100, or its mixture with a cosurfactant, i.e. butanol. The investigation covered the whole water content range through various (Winsor I-III and dissolved solution) structures of the system. The comparative approach allowed closer inspection into phenomena being on the background of observed transport properties behavior taking into account the influence of the cosurfactant. The addition of butanol offers considerable advantages, such as an increase in conductivity, especially in systems containing ionic liquids with lower conductivity. This is accompanied by a significant decrease in viscosity, even to values that are comparable with those of molecular solvents. Moreover, the reasons for the surprisingly higher conductivity of [BMIM][PF6]-based systems were provided, and the conclusions were supported by cyclic voltammetry as well as spectrophotometric and dynamic light scattering measurements.

  8. Heterogeneity in a room-temperature ionic liquid: persistent local environments and the red-edge effect.

    PubMed

    Hu, Zhonghan; Margulis, Claudio J

    2006-01-24

    In this work, we investigate the slow dynamics of 1-butyl-3-methylimidazolium hexafluorophosphate, a very popular room-temperature ionic solvent. Our study predicts the existence of heterogeneity in the liquid and shows that this heterogeneity is the underlying microscopic cause for the recently reported "red-edge effect" (REE) observed in the study of fluorescence of the organic probe 2-amino-7-nitrofluorene. This theoretical work explains in microscopic terms the relation between REE and dynamic heterogeneity in a room-temperature ionic liquid (IL). The REE is typical of micellar or colloidal systems, which are characterized by microscopic environments that are structurally very different. In contrast, in the case of this room-temperature IL, the REE occurs because of the long period during which molecules are trapped in quasistatic local solvent cages. This trapping time, which is longer than the lifetime of the excited-state probe, together with the inability of the surroundings to adiabatically relax, induces a set of site-specific spectroscopic responses. Subensembles of fluorescent molecules associated with particular local environments absorb and emit at different frequencies. We describe in detail the absorption wavelength-dependent emission spectra of 2-amino-7-nitrofluorene and show that this dependence on lambda(ex) is characteristic of the IL and, as is to be expected, is absent in the case of a normal solvent such as methanol.

  9. Flow-Tube Investigations of Hypergolic Reactions of a Dicyanamide Ionic Liquid Via Tunable Vacuum Ultraviolet Aerosol Mass Spectrometry.

    PubMed

    Chambreau, Steven D; Koh, Christine J; Popolan-Vaida, Denisia M; Gallegos, Christopher J; Hooper, Justin B; Bedrov, Dmitry; Vaghjiani, Ghanshyam L; Leone, Stephen R

    2016-10-07

    The unusually high heats of vaporization of room-temperature ionic liquids (RTILs) complicate the utilization of thermal evaporation to study ionic liquid reactivity. Although effusion of RTILs into a reaction flow-tube or mass spectrometer is possible, competition between vaporization and thermal decomposition of the RTIL can greatly increase the complexity of the observed reaction products. In order to investigate the reaction kinetics of a hypergolic RTIL, 1-butyl-3-methylimidazolium dicyanamide (BMIM(+)DCA(-)) was aerosolized and reacted with gaseous nitric acid, and the products were monitored via tunable vacuum ultraviolet photoionization time-of-flight mass spectrometry at the Chemical Dynamics Beamline 9.0.2 at the Advanced Light Source. Reaction product formation at m/z 42, 43, 44, 67, 85, 126, and higher masses was observed as a function of HNO3 exposure. The identities of the product species were assigned to the masses on the basis of their ionization energies. The observed exposure profile of the m/z 67 signal suggests that the excess gaseous HNO3 initiates rapid reactions near the surface of the RTIL aerosol. Nonreactive molecular dynamics simulations support this observation, suggesting that diffusion within the particle may be a limiting step. The mechanism is consistent with previous reports that nitric acid forms protonated dicyanamide species in the first step of the reaction.

  10. Separation and determination of lignans from seeds of Schisandra species by micellar electrokinetic capillary chromatography using ionic liquid as modifier.

    PubMed

    Tian, Kan; Qi, Shengda; Cheng, Yuqiao; Chen, Xingguo; Hu, Zhide

    2005-06-17

    In this paper, a micellar electrokinetic chromatographic (MEKC) method using ionic liquid as modifier for the quantification of the active components of lignans found in the medicinal herbs Schisandra species was developed for the first time. Preliminary investigations employing sodium dodecyl sulfate (SDS) as surfactant did not lead to the necessary resolution of the studied compounds, the addition of ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM-BF4) to the SDS micellar system resulted in the complete separation of all the compounds. The effects on the separation by several parameters such as BMIM-BF4 and SDS concentration, applied voltage, background electrolyte pH and concentration, were evaluated. Under the optimal conditions (5 mM borate-5 mM phosphate buffer in the presence of 20 mM SDS and 10 mM BMIM-BF4, pH 9.2, applied voltage 25 kV and detection at 254 nm), the method successfully applied to the determination of lignans in extracts of Schisandra chinensis (Turcz.) Baill. and Schisandra henryi C.B. Clarke in less than 13 min. The separation mechanism was also discussed.

  11. Halloysite clay nanotubes and platinum nanoparticles dispersed in ionic liquid applied in the development of a catecholamine biosensor.

    PubMed

    Brondani, Daniela; Scheeren, Carla Weber; Dupont, Jairton; Vieira, Iolanda Cruz

    2012-08-21

    Halloysite clay nanotubes were used as a support for the immobilization of the enzyme peroxidase from clover sprouts (Trifolium), and employed together with platinum nanoparticles in 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid (Pt-BMI·PF(6)) in the development of a new biosensor for the determination of catecholamines by square-wave voltammetry. Under optimized conditions, the analytical curves showed detection limits of 0.05, 0.06, 0.07, 0.12 μM for dopamine, isoproterenol, dobutamine and epinephrine, respectively. The biosensor demonstrated high sensitivity, good repeatability and reproducibility, and long-term stability (18% decrease in response over 150 days). A recovery study of dopamine in pharmaceutical samples gave values from 97.5 to 101.4%. The proposed biosensor was successfully applied to the determination of dopamine in pharmaceutical samples, with a maximum relative error of ±1.0% in relation to the standard (spectrophotometric) method. The good analytical performance of the proposed method can be attributed to the efficient immobilization of the peroxidase in the nanoclay, and the facilitation of electron transfer between the protein and the electrode surface due to the presence of the Pt nanoparticles and ionic liquid.

  12. Extraction of testosterone and epitestosterone in human urine using aqueous two-phase systems of ionic liquid and salt.

    PubMed

    He, Chiyang; Li, Shehong; Liu, Huwei; Li, Kean; Liu, Feng

    2005-08-05

    Based on aqueous two-phase systems (ATPS) consisting of 1-butyl-3-methylimidazolium chloride, a hydrophilic ionic liquid (IL), and K2HPO4, a new and simple extraction technique, coupled with a reversed-phase high performance liquid chromatography (RP-HPLC), was developed for the simultaneous concentration and analysis of testosterone (T) and epitestosterone (ET) in human urine. Under the optimal conditions, the extraction efficiencies for both analytes were 80-90% in a one-step extraction. The method required only 3.0 mL of urine and a single hydrolysis/deproteinization/extraction step followed by direct injection of the IL-rich upper phase into HPLC system for analysis. The method has been satisfactorily applied to the analysis of T and ET in human urine with detection limits of 1 ng/mL and linear ranges of 10-500 ng/mL for both compounds. Compared with conventional liquid-liquid extraction or solid phase extraction, this new method is much "greener" due to no use of volatile organic solvent and low consumption of IL. The proposed extraction technique opens up new possibilities in the separation of other drugs.

  13. Simulation of a cellulose fiber in ionic liquid suggests a synergistic approach to dissolution

    DOE PAGES

    Mostofian, Barmak; Smith, Jeremy C.; Cheng, Xiaolin

    2013-08-11

    Ionic liquids dissolve cellulose in a more efficient and environmentally acceptable way than conventional methods in aqueous solution. An understanding of how ionic liquids act on cellulose is essential for improving pretreatment conditions and thus detailed knowledge of the interactions between the cations, anions and cellulose is necessary. Here in this study, to explore ionic liquid effects, we perform all-atom molecular dynamics simulations of a cellulose microfibril in 1-butyl-3-methylimidazolium chloride and analyze site–site interactions and cation orientations at the solute–solvent interface. The results indicate that Cl- anions predominantly interact with cellulose surface hydroxyl groups but with differences between chains ofmore » neighboring cellulose layers, referred to as center and origin chains; Cl- binds to C3-hydroxyls on the origin chains but to C2- and C6-hydroxyls on the center chains, thus resulting in a distinct pattern along glucan chains of the hydrophilic fiber surfaces. In particular, Cl- binding disrupts intrachain O3H–O5 hydrogen bonds on the origin chains but not those on the center chains. In contrast, Bmim+ cations stack preferentially on the hydrophobic cellulose surface, governed by non-polar interactions with cellulose. Complementary to the polar interactions between Cl- and cellulose, the stacking interaction between solvent cation rings and cellulose pyranose rings can compensate the interaction between stacked cellulose layers, thus stabilizing detached cellulose chains. Moreover, a frequently occurring intercalation of Bmim+ on the hydrophilic surface is observed, which by separating cellulose layers can also potentially facilitate the initiation of fiber disintegration. The results provide a molecular description why ionic liquids are ideal cellulose solvents, the concerted action of anions and cations on the hydrophobic and hydrophilic surfaces being key to the efficient dissolution of the amphiphilic carbohydrate.« less

  14. Simulation of a cellulose fiber in ionic liquid suggests a synergistic approach to dissolution

    SciTech Connect

    Mostofian, Barmak; Smith, Jeremy C.; Cheng, Xiaolin

    2013-08-11

    Ionic liquids dissolve cellulose in a more efficient and environmentally acceptable way than conventional methods in aqueous solution. An understanding of how ionic liquids act on cellulose is essential for improving pretreatment conditions and thus detailed knowledge of the interactions between the cations, anions and cellulose is necessary. Here in this study, to explore ionic liquid effects, we perform all-atom molecular dynamics simulations of a cellulose microfibril in 1-butyl-3-methylimidazolium chloride and analyze site–site interactions and cation orientations at the solute–solvent interface. The results indicate that Cl- anions predominantly interact with cellulose surface hydroxyl groups but with differences between chains of neighboring cellulose layers, referred to as center and origin chains; Cl- binds to C3-hydroxyls on the origin chains but to C2- and C6-hydroxyls on the center chains, thus resulting in a distinct pattern along glucan chains of the hydrophilic fiber surfaces. In particular, Cl- binding disrupts intrachain O3H–O5 hydrogen bonds on the origin chains but not those on the center chains. In contrast, Bmim+ cations stack preferentially on the hydrophobic cellulose surface, governed by non-polar interactions with cellulose. Complementary to the polar interactions between Cl- and cellulose, the stacking interaction between solvent cation rings and cellulose pyranose rings can compensate the interaction between stacked cellulose layers, thus stabilizing detached cellulose chains. Moreover, a frequently occurring intercalation of Bmim+ on the hydrophilic surface is observed, which by separating cellulose layers can also potentially facilitate the initiation of fiber disintegration. The results provide a molecular description why ionic liquids are ideal cellulose solvents, the concerted action of anions and cations on the hydrophobic and hydrophilic surfaces being key to the efficient

  15. Fabrication of hollow mesoporous NiO hexagonal microspheres via hydrothermal process in ionic liquid

    SciTech Connect

    Zhao, Jinbo; Wu, Lili; Zou, Ke

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer Ni(OH){sub 2} precursors were synthesized in ionic liquid and water solution by hydrothermal method. Black-Right-Pointing-Pointer NiO hollow microspheres were prepared by thermal treatment of Ni(OH){sub 2} precursors. Black-Right-Pointing-Pointer NiO hollow microspheres were self-assembled by mesoporous cubic and hexagonal nanocrystals with high specific surface area. Black-Right-Pointing-Pointer The mesoporous structure is stable at 773 K. Black-Right-Pointing-Pointer The ionic liquid absorbed on the O-terminate surface of the crystals to form hydrogen bond and played key roles in determining the final shape of the NiO novel microstructure. -- Abstract: The novel NiO hexagonal hollow microspheres have been successfully prepared by annealing Ni(OH){sub 2}, which was synthesized via an ionic liquid-assisted hydrothermal method. The samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), transmission electron microscopy (TEM), N{sub 2} adsorption-desorption and Fourier transform infrared spectrometer (FTIR). The results show that the hollow NiO microstructures are self-organized by mesoporous cubic and hexagonal nanocrystals. The mesoporous structure possessed good thermal stability and high specific surface area (ca. 83 m{sup 2}/g). The ionic liquid 1-butyl-3methylimidazolium tetrafluoroborate ([Bmim][BF{sub 4}]) was found to play a key role in controlling the morphology of NiO microstructures during the hydrothermal process. The special hollow mesoporous architectures will have potential applications in many fields, such as catalysts, absorbents, sensors, drug-delivery carriers, acoustic insulators and supercapacitors.

  16. Thermostable gel polymer electrolyte based on succinonitrile and ionic liquid for high-performance solid-state supercapacitors

    NASA Astrophysics Data System (ADS)

    Pandey, Gaind P.; Liu, Tao; Hancock, Cody; Li, Yonghui; Sun, Xiuzhi Susan; Li, Jun

    2016-10-01

    A flexible, free-standing, thermostable gel polymer electrolyte based on plastic crystalline succinonitrile (SN) and ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate (BMImBF4) entrapped in copolymer poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) is prepared and optimized for application in solvent-free solid-state supercapacitors. The synthesized gel polymer electrolyte exhibits a high ionic conductivity over a wide temperature range (from ∼5 × 10-4 S cm-1 at -30 °C up to ∼1.5 × 10-2 S cm-1 at 80 °C) with good electrochemical stability window (-2.9 to 2.5 V). Thermal studies confirm that the SN containing gel polymer electrolyte remains stable in the same gel phase over a wide temperature range from -30 to 90 °C. The electric double layer capacitors (EDLCs) have been fabricated using activated carbon as active materials and new gel polymer electrolytes. Electrochemical performance of the EDLCs is assessed through cyclic voltammetry, galvanostatic charge-discharge cycling and impedance spectroscopy. The EDLC cells with the proper SN-containing gel polymer electrolyte has been found to give high specific capacitance 176 F g-1 at 0.18 A g-1 and 138 F g-1 at 8 A g-1. These solid-state EDLC cells show good cycling stability and the capability to retain ∼80% of the initial capacitance after 10,000 cycles.

  17. Performance of Liquid Phase Exfoliated Graphene As Electrochemical Double Layer Capacitors Electrodes

    NASA Astrophysics Data System (ADS)

    Huffstutler, Jacob; Wasala, Milinda; Richie, Julianna; Winchester, Andrew; Ghosh, Sujoy; Kar, Swastik; Talapatra, Saikat

    2014-03-01

    We will present the results of our investigations of electrochemical double layer capacitors (EDLCs) or supercapacitors (SC) fabricated using liquid-phase exfoliated graphene. Several electrolytes, such as aqueous potassium hydroxide KOH (6M), ionic 1-Butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6], and ionic 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate[BMP][FAP] were used. These EDLC's show good performance compared to other carbon nanomaterials based EDLC's devices. We found that the liquid phase exfoliated graphene based devices possess specific capacitance values as high as 262 F/g, when used with ionic liquid electrolyte[BMP][FAP], with power densities (~ 454 W/kg) and energy densities (~ 0.38Wh/kg). Further, these devices indicated rapid charge transfer response even without the use of any binders or specially prepared current collectors. A detailed electrochemical impedance spectroscopy analysis in order to understand the phenomenon of charge storage in these materials will be presented.

  18. NMR Diffusion Measurements as a Simple Method to Examine Solvent-Solvent and Solvent-Solute Interactions in Mixtures of the Ionic Liquid [Bmim][N(SO2 CF3 )2 ] and Acetonitrile.

    PubMed

    Keaveney, Sinead T; Schaffarczyk McHale, Karin S; Stranger, James W; Ganbold, Batchimeg; Price, William S; Harper, Jason B

    2016-12-05

    The self-diffusion coefficients of each component in mixtures of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([Bmim][N(SO2 CF3 )2 ]) and acetonitrile were determined. The results suggest that the hydrodynamic boundary conditions change from "stick" to "slip" as the solvent composition transitions from "ionic liquid dissolved in acetonitrile" (χIL <0.4) to "acetonitrile dissolved in ionic liquid" (χIL >0.4). At higher χIL , the acetonitrile species are affected by "cage" and "jump" events, as the acetonitrile molecules reside nearer to the charged centre on the ions than in the "non-polar" regions. The self-diffusion coefficients of hexan-1-amine, dipropylamine, 1-hexanol and dipropylether in mixtures of [Bmim][N(SO2 CF3 )2 ] and acetonitrile were determined. In general, the nitrogen-containing solutes were found to diffuse slower than the oxygen-containing solutes; this indicates that there are greater ionic liquid-N interactions than ionic liquid-O interactions. This work demonstrates that the self-diffusion coefficients of species can provide valuable information about solvent-solvent and solvent-solute interactions in mixtures containing an ionic liquid.

  19. Ionic liquid and aqueous two-phase extraction based on salting-out coupled with high-performance liquid chromatography for the determination of seven rare ginsenosides in Xue-Sai-Tong injection.

    PubMed

    Li, Lan-Jie; Jin, Yong-Ri; Wang, Xiao-Zhong; Liu, Ying; Wu, Qian; Shi, Xiao-Lei; Li, Xu-Wen

    2015-09-01

    A method of ionic liquid salt aqueous two-phase extraction coupled with high-performance liquid chromatography has been developed for the analysis of seven rare ginsenosides including Rg6 , F4 , 20(S)-Rg3 , 20(R)-Rg3 , Rk3 , Rk1 , and Rg5 in Xue-Sai-Tong injection. The injection was mixed with ionic liquid 1-butyl-3-methylimidazolium bromide aqueous solution, and a mixture was obtained. With the addition of sodium dodecyl sulfate and dipotassium phosphate into the mixture, the aqueous two-phase mixture was formed after ultrasonic treatment and centrifuged. Rare ginsenosides were extracted into the upper phase. To obtain a high extraction factors, various influences were considered systematically, such as the volume of ionic liquid, the category and amount of salts, the amount of sodium dodecyl sulfate, the pH value of system, and the time of ultrasonic treatment. Under the optimal condition, rare ginsenosides in Xue-Sai-Tong injection were enriched and detected, the recoveries of seven rare ginsenosides ranged from 90.05 to 112.55%, while relative standard deviations were lower than 2.50%. The developed method was reliable, rapid and sensitive for the determination of seven rare ginsenosides in the injections. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Reactable ionic liquid assisted solvothermal synthesis of graphite-like C3N4 hybridized α-Fe2O3 hollow microspheres with enhanced supercapacitive performance

    NASA Astrophysics Data System (ADS)

    Xu, Li; Xia, Jiexiang; Xu, Hui; Yin, Sheng; Wang, Kun; Huang, Liying; Wang, Leigang; Li, Huaming

    2014-01-01

    A route to fabricate the graphite-like C3N4 hybridized α-Fe2O3 (g-C3N4/α-Fe2O3) hollow microspheres is designed. This route develops an ionic liquid system containing iron ions for manufacturing the g-C3N4/α-Fe2O3 hollow microspheres by a novel and eco-friendly solvothermal method at low temperature condition. The effect of ionic liquids on the morphology of the g-C3N4/α-Fe2O3 hybrid composites has been investigated in detail. It is found that ionic liquid 1-butyl-3-methylimidazolium tetrachlorideferrate(III) [Bmim]FeCl4 is supposed to have the triple roles of reactant, dispersing media and template at the same time, and is vital for the structure of the g-C3N4/α-Fe2O3 hollow microspheres. In addition, the capacitance of the g-C3N4/α-Fe2O3 hollow microspheres as electrode materials for supercapacitors is tested by cyclic voltammetry and chronopotentiometry measurements. The g-C3N4/α-Fe2O3 hollow microspheres exhibit large specific capacitance, excellent cycling performance and high Coulombic efficiency. The designed g-C3N4/α-Fe2O3 hollow microspheres show potential applications in supercapacitors.

  1. Ionic liquid-based extraction followed by graphite-furnace atomic absorption spectrometry for the determination of trace heavy metals in high-purity iron metal.

    PubMed

    Matsumiya, Hiroaki; Kato, Tatsuya; Hiraide, Masataka

    2014-02-01

    The analysis of high-purity materials for trace impurities is an important and challenging task. The present paper describes a facile and sensitive method for the determination of trace heavy metals in high-purity iron metal. Trace heavy metals in an iron sample solution were rapidly and selectively preconcentrated by the extraction into a tiny volume of an ionic liquid [1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide] for the determination by graphite-furnace atomic absorption spectrometry (GFAAS). A nitrogen-donating neutral ligand, 2,4,6-tris(2-pyridyl)-1,3,5-triazine (TPTZ), was found to be effective in the ionic liquid-based selective extraction, allowing the nearly complete (~99.8%) elimination of the iron matrix. The combination with the optimized GFAAS was successful. The detectability reached sub-μg g(-1) levels in iron metal. The novel use of TPTZ in ionic liquid-based extraction followed by GFAAS was successfully applied to the determination of traces of Co, Ni, Cu, Cd, and Pb in certified reference materials for high-purity iron metal.

  2. The effect of the number of alkyl substituents on imidazolium ionic liquids phytotoxicity and oxidative stress in spring barley and common radish seedlings.

    PubMed

    Biczak, Robert; Pawłowska, Barbara; Telesiński, Arkadiusz; Ciesielski, Wojciech

    2016-12-01

    Increasing amounts of two ILs: 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6] and 1-butyl-2,3-dimethylimidazolium hexafluorophosphate [BMMIM][PF6], were introduced to soil in which spring barley (Hordeum vulgare) and common radish (Raphanus sativus L. subvar. radicula Pers.) seedlings were cultivated, in order to evaluate the phytotoxicity of ionic liquids with imidazolium cation with two or three alkyl substituents attached. The results of the study i.e. the inhibition of the length of plants and their roots, as well as the yield of fresh weight of plants, clearly showed that differences in the number of substituents did not affect the toxicity of these ILs. Although, radish was more resistant to the applied ionic liquids than barley. Ionic liquids led to a decrease in the content of all assimilation pigments and induced oxidative stress in the plants, as showed by an increase in malondialdehyde (MDA) content, and changes in the level of H2O2 and antioxidant enzymes: superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD). The best biomarkers of oxidative stress in both plants were the changes in chlorophyll content and the increase in POD activity. Both spring barley and radish exposed to [BMIM][PF6] and [BMMIM][PF6] accumulated a large amount of fluoride ions, which further increased the toxicity of these compounds for both plants.

  3. Catalysis of rice straw hydrolysis by the combination of immobilized cellulase from Aspergillus niger on β-cyclodextrin-Fe3O4 nanoparticles and ionic liquid.

    PubMed

    Huang, Po-Jung; Chang, Ken-Lin; Hsieh, Jung-Feng; Chen, Shui-Tein

    2015-01-01

    Cellulase from Aspergillus niger was immobilized onto β-cyclodextrin-conjugated magnetic particles by silanization and reductive amidation. The immobilized cellulase gained supermagnetism due to the magnetic nanoparticles. Ninety percent of cellulase was immobilized, but the activity of immobilized cellulase decreased by 10%. In this study, ionic liquid (1-butyl-3-methylimidazolium chloride) was introduced into the hydrolytic process because the original reaction was a solid-solid reaction. The activity of immobilized cellulase was improved from 54.87 to 59.11 U g immobilized cellulase(-1) at an ionic liquid concentration of 200 mM. Using immobilized cellulase and ionic liquid in the hydrolysis of rice straw, the initial reaction rate was increased from 1.629 to 2.739 g h(-1) L(-1). One of the advantages of immobilized cellulase is high reusability--it was usable for a total of 16 times in this study. Compared with free cellulase, magnetized cellulase can be recycled by magnetic field and the activity of immobilized cellulase was shown to remain at 85% of free cellulase without denaturation under a high concentration of glucose (15 g L(-1)). Therefore, immobilized cellulase can hydrolyze rice straw continuously compared with free cellulase. The amount of harvested glucose can be up to twentyfold higher than that from the hydrolysis by free cellulase.

  4. Syntheses and crystal structures of benzene-sulfonate and -carboxylate copper polymers and their application in the oxidation of cyclohexane in ionic liquid under mild conditions.

    PubMed

    Hazra, Susanta; Ribeiro, Ana P C; Guedes da Silva, M Fátima C; Nieto de Castro, Carlos A; Pombeiro, Armando J L

    2016-09-21

    The syntheses, crystal structures and catalytic activities of the polymers derived from 2-(2-pyridylmethyleneamino)benzenesulfonic acid (HL), viz. [CuL(H2tma)]n (1) and [{Cu2L2(H2pma)}·(8H2O)]n (2) [H3tma = benzene-1,3,5-tricarboxylic (trimesic) acid and H4pma = benzene-1,2,4,5-tetracarboxylic (pyromellitic) acid], are presented. Despite the comparable combinations and compositions of ligands (sulfonate and carboxylate) in these two polymers the bridging moiety in 1 is sulfonate while in 2 it is carboxylate. Complexes 1 and 2 act as catalysts in the peroxidative oxidation of cyclohexane under mild conditions using either the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate [bmim][PF6] or acetonitrile as the solvent. The ionic liquid medium leads to increases in the yields and in the turnover numbers, achieved in shorter reaction times in comparison with those when using the conventional acetonitrile solvent. A simple recycling of the catalysts in the ionic liquid medium is achieved without loss of activity and selectivity.

  5. Catalysis of Rice Straw Hydrolysis by the Combination of Immobilized Cellulase from Aspergillus niger on β-Cyclodextrin-Fe3O4 Nanoparticles and Ionic Liquid

    PubMed Central

    Huang, Po-Jung; Chang, Ken-Lin; Chen, Shui-Tein

    2015-01-01

    Cellulase from Aspergillus niger was immobilized onto β-cyclodextrin-conjugated magnetic particles by silanization and reductive amidation. The immobilized cellulase gained supermagnetism due to the magnetic nanoparticles. Ninety percent of cellulase was immobilized, but the activity of immobilized cellulase decreased by 10%. In this study, ionic liquid (1-butyl-3-methylimidazolium chloride) was introduced into the hydrolytic process because the original reaction was a solid-solid reaction. The activity of immobilized cellulase was improved from 54.87 to 59.11 U g immobilized cellulase−1 at an ionic liquid concentration of 200 mM. Using immobilized cellulase and ionic liquid in the hydrolysis of rice straw, the initial reaction rate was increased from 1.629 to 2.739 g h−1 L−1. One of the advantages of immobilized cellulase is high reusability—it was usable for a total of 16 times in this study. Compared with free cellulase, magnetized cellulase can be recycled by magnetic field and the activity of immobilized cellulase was shown to remain at 85% of free cellulase without denaturation under a high concentration of glucose (15 g L−1). Therefore, immobilized cellulase can hydrolyze rice straw continuously compared with free cellulase. The amount of harvested glucose can be up to twentyfold higher than that from the hydrolysis by free cellulase. PMID:25874210

  6. Conformational and Dynamic Properties of Poly(ethylene oxide) in an Ionic Liquid: Development and Implementation of a First-Principles Force Field.

    PubMed

    McDaniel, Jesse G; Choi, Eunsong; Son, Chang-Yun; Schmidt, J R; Yethiraj, Arun

    2016-01-14

    The conformational properties of polymers in ionic liquids are of fundamental interest but not well understood. Atomistic and coarse-grained molecular models predict qualitatively different results for the scaling of chain size with molecular weight, and experiments on dilute solutions are not available. In this work, we develop a first-principles force field for poly(ethylene oxide) (PEO) in the ionic liquid 1-butyl 3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) using symmetry adapted perturbation theory (SAPT). At temperatures above 400 K, simulations employing both the SAPT and OPLS-AA force fields predict that PEO displays ideal chain behavior, in contrast to previous simulations at lower temperature. We therefore argue that the system shows a transition from extended to more compact configurations as the temperature is increased from room temperature to the experimental lower critical solution temperature. Although polarization is shown to be important, its implicit inclusion in the OPLS-AA force is sufficient to describe the structure and energetics of the mixture. The simulations emphasize the difference between ionic liquids from typical solvents for polymers.

  7. Room-temperature ionic liquids as electrolytes in electroanalytical determination of traces of 2-furaldehyde from oil and related wastewaters from refining processes.

    PubMed

    Shamsipur, Mojtaba; Beigi, Ali Akbar Miran; Teymouri, Mohammad; Ghorbani, Yousefali; Irandoust, Mohsen; Mehdizadeh, Ali

    2010-04-15

    Three different ionic liquids, 1-ethyl-3-methylimidazolium tetrafluoroborate, [EMIM][BF(4)]; 1-butyl-3-methylimidazolium trifluoromethanesulfonate, [BMIM][OTf]; and 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide [bmpyrr][NTf(2)] were studied as electrolytes in the electroanalytical quantification of 2-furaldehyde using square wave and differential pulse voltammetries. On applying a cathodic scan, a well-defined 2-electron wave was observed corresponding to the reduction of 2-furaldehyde to furfuryl alcohol. The electrochemical stability of the ionic liquids as electrolytes for analytical aspects and electrokinetic studies was investigated using a glassy carbon electrode (GCE). The measurements were carried out in a designed double-wall three-electrode cell, using two platinum wires as the quasi-reference and counter electrodes. Differential pulse voltammetry was found to be the most sensitive method at GCE. The detection limits of 1.4, 19.0 and 2.5 microg g(-1) were obtained for the determination of 2-furaldehyde in [EMIM][BF(4)], [BMIM][OTf] and [BMPyrr][NTf(2)], respectively. At a concentration of 50 microg g(-1), the maximum relative standard deviation (n=3) was 4.9%. The effect of water content of the ionic liquids on their potential windows and waveforms was also investigated. The proposed method was successfully applied to the determination of 2-furaldehyde in real samples, especially in oil matrices. (c) 2009 Elsevier B.V. All rights reserved.

  8. Functionalization of carbon nanotubes with water-insoluble porphyrin in ionic liquid: direct electrochemistry and highly sensitive amperometric biosensing for trichloroacetic acid.

    PubMed

    Tu, Wenwen; Lei, Jianping; Ju, Huangxian

    2009-01-01

    A functional composite of single-walled carbon nanotubes (SWNTs) with hematin, a water-insoluble porphyrin, was first prepared in 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF(6)]) ionic liquid. The novel composite in ionic liquid was characterized by scanning electron microscopy, ultraviolet absorption spectroscopy, and electrochemical impedance spectroscopy, and showed a pair of direct redox peaks of the Fe(III)/Fe(II) couple. The composite-[BMIM][PF(6)]-modified glassy carbon electrode showed excellent electrocatalytic activity toward the reduction of trichloroacetic acid (TCA) in neutral media due to the synergic effect among SWNTs, [BMIM][PF(6)], and porphyrin, which led to a highly sensitive and stable amperometric biosensor for TCA with a linear range from 9.0x10(-7) to 1.4x10(-4) M. The detection limit was 3.8x10(-7) M at a signal-to-noise ratio of 3. The TCA biosensor had good analytical performance, such as rapid response, good reproducibility, and acceptable accuracy, and could be successfully used for the detection of residual TCA in polluted water. The functional composite in ionic liquid provides a facile way to not only obtain the direct electrochemistry of water-insoluble porphyrin, but also construct novel biosensors for monitoring analytes in real environmental samples.

  9. Rapid and sensitive analysis of microcystins using ionic liquid-based in situ dispersive liquid-liquid microextraction.

    PubMed

    Yu, Honglian; Clark, Kevin D; Anderson, Jared L

    2015-08-07

    Three structurally different ionic liquids (ILs), namely 1-butyl-3-methylimidazolium chloride ([BMIM][Cl]), 1-(6-hydroxyethyl)-3-methylimidazolium chloride ([HeOHMIM][Cl]) and 1-benzyl-3-(2-hydroxyethyl)imidazolium bromide ([BeEOHIM][Br]), were applied as extraction solvents using in situ dispersive liquid-liquid microextraction (in situ DLLME) for the preconcentration of two microcystin variants, microcystin-RR (MC-RR) and microcystin-LR (MC-LR) from aqueous samples. Extraction parameters including sample solution pH, ratio of IL to metathesis reagent, sample volume, IL quantity, and salt concentration were optimized to achieve the best extraction efficiency. The [BeEOHIM][Br] IL, which contains both an aromatic moiety and a hydroxyl group within its chemical structure, exhibited superior extraction efficiency compared to the other two ILs. The analytical performance of the [BeEOHIM][Br] IL as an extraction solvent for in situ DLLME of microcystins was investigated using HPLC-UV and HPLC-MS. The limits of detection (LODs) for MC-RR and MC-LR were 0.7μgL(-1) using UV detection with a linear range from 1 to 50μgL(-1). The separation method was successfully adapted for ESI-MS/SIM detection, wherein the LODs for MC-RR and MC-LR were greatly improved to 0.005 and 0.003μgL(-1), respectively. The accuracy of the method was demonstrated by examining the relative recovery using tap water and river water and produced recoveries ranging from 45.0 to 109.7% and from 46.3 to 103.2%, respectively.

  10. Regenerating cellulose from ionic liquids for an accelerated enzymatic hydrolysis

    SciTech Connect

    Zhao, Hua; Jones, Cecil L; Baker, Gary A; Xia, Shuqian; Olubajo, Olarongbe; Person, Vernecia

    2009-01-01

    The efficient conversion of lignocellulosic materials into fuel ethanol has become a research priority in producing affordable and renewable energy. The pretreatment of lignocelluloses is known to be key to the fast enzymatic hydrolysis of cellulose. Recently, certain ionic liquids (ILs)were found capable of dissolving more than 10 wt% cellulose. Preliminary investigations [Dadi, A.P., Varanasi, S., Schall, C.A., 2006. Enhancement of cellulose saccharification kinetics using an ionic liquid pretreatment step. Biotechnol. Bioeng. 95, 904 910; Liu, L., Chen, H., 2006. Enzymatic hydrolysis of cellulose materials treated with ionic liquid [BMIM]Cl. Chin. Sci. Bull. 51, 2432 2436; Dadi, A.P., Schall, C.A., Varanasi, S., 2007. Mitigation of cellulose recalcitrance to enzymatic hydrolysis by ionic liquid pretreatment. Appl. Biochem. Biotechnol. 137 140, 407 421] suggest that celluloses regenerated from IL solutions are subject to faster saccharification than untreated substrates. These encouraging results offer the possibility of using ILs as alternative and nonvolatile solvents for cellulose pretreatment. However, these studies are limited to two chloride-based ILs: (a) 1-butyl-3-methylimidazolium chloride ([BMIM]Cl), which is a corrosive, toxic and extremely hygroscopic solid (m.p. 70 C), and (b) 1-allyl-3-methylimidazolium chloride ([AMIM]Cl), which is viscous and has a reactive side-chain. Therefore, more in-depth research involving other ILs is much needed to explore this promising pretreatment route. For this reason, we studied a number of chloride- and acetate-based ILs for cellulose regeneration, including several ILs newly developed in our laboratory. This will enable us to select inexpensive, efficient and environmentally benign solvents for processing cellulosic biomass. Our data confirm that all regenerated celluloses are less crystalline (58 75% lower) and more accessible to cellulase (>2 times) than untreated substrates. As a result, regenerated Avicel

  11. Application of ionic liquids for elution of bioactive flavonoid glycosides from lime fruit by miniaturized matrix solid-phase dispersion.

    PubMed

    Xu, Jing-Jing; Yang, Rui; Ye, Li-Hong; Cao, Jun; Cao, Wan; Hu, Shuai-Shuai; Peng, Li-Qing

    2016-08-01

    In this work, two flavonoid glycosides (neohesperidin and naringin) in lime fruit were effectively extracted by miniaturized matrix solid phase dispersion (MSPD), followed by ultra-performance liquid chromatography-ultraviolet detection. The best results were obtained using Florisil (150mg) as the sorbent and 1-butyl-3-methylimidazolium tetrafluoroborate (0.4mL, 250mM) as the elution solvent. This work represents the first attempt of using ionic liquids as a green eluent for extraction of the investigated compounds in miniaturized MSPD. Compared with the conventional methods, the proposed method is advantageous due to improved enrichment factor and reduced reagent consumption. A good linearity was observed with r(2) values (>0.998). Meanwhile, the method gave acceptable recoveries (90.16-96.47%) for the determination of flavonoids in plant samples. The limits of detection of the two analytes ranged between 4.08 and 5.04μg/g. The results showed that the optimized method has a great potential for sample preparation in routine analysis of complex plant samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Insights into the mechanism of extraction of uranium (VI) from nitric acid solution into an ionic liquid by using tri-n-butyl phosphate.

    PubMed

    Gaillard, Dr Clotilde; Boltoeva, Maria; Billard, Isabelle; Georg, Sylvia; Mazan, Valérie; Ouadi, Ali; Ternova, Dariia; Hennig, Christoph

    2015-08-24

    We present new results on the liquid-liquid extraction of uranium (VI) from a nitric acid aqueous phase into a tri-n-butyl phosphate/1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (TBP/[C4 mim][Tf2 N]) phase. The individual solubilities of the ionic-liquid ions in the upper part of the biphasic system are measured over the whole acidic range and as a function of the TBP concentration. New insights into the extraction mechanism are obtained through the in situ characterization of the extracted uranyl complexes by coupling UV/Vis and extended X-ray absorption fine structure (EXAFS) spectroscopy. We propose a chemical model to explain uranium (VI) extraction that describes the data through a fit of the uranyl distribution ratio DU . In this model, at low acid concentrations uranium (VI) is extracted as the cationic complex [UO2 (TBP)2 ](2+) , by an exchange with one proton and one C4 mim(+) . At high acid concentrations, the extraction proceeds through a cationic exchange between [UO2 (NO3 )(HNO3 )(TBP)2 ](+) and one C4 mim(+) . As a consequence of this mechanism, the variation of DU as a function of TBP concentration depends on the C4 mim(+) concentration in the aqueous phase. This explains why noninteger values are often derived by analysis of DU versus [TBP] plots to determine the number of TBP molecules involved in the extraction of uranyl in an ionic-liquid phase.

  13. A new dispersive liquid-liquid microextraction using ionic liquid based microemulsion coupled with cloud point extraction for determination of copper in serum and water samples.

    PubMed

    Arain, Salma Aslam; Kazi, Tasneem Gul; Afridi, Hassan Imran; Arain, Mariam Shahzadi; Panhwar, Abdul Haleem; Khan, Naeemullah; Baig, Jameel Ahmed; Shah, Faheem

    2016-04-01

    A simple and rapid dispersive liquid-liquid microextraction procedure based on ionic liquid assisted microemulsion (IL-µE-DLLME) combined with cloud point extraction has been developed for preconcentration copper (Cu(2+)) in drinking water and serum samples of adolescent female hepatitits C (HCV) patients. In this method a ternary system was developed to form microemulsion (µE) by phase inversion method (PIM), using ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([C4mim][PF6]) and nonionic surfactant, TX-100 (as a stabilizer in aqueous media). The Ionic liquid microemulsion (IL-µE) was evaluated through visual assessment, optical light microscope and spectrophotometrically. The Cu(2+) in real water and aqueous acid digested serum samples were complexed with 8-hydroxyquinoline (oxine) and extracted into IL-µE medium. The phase separation of stable IL-µE was carried out by the micellar cloud point extraction approach. The influence of of different parameters such as pH, oxine concentration, centrifugation time and rate were investigated. At optimized experimental conditions, the limit of detection and enhancement factor were found to be 0.132 µg/L and 70 respectively, with relative standard deviation <5%. In order to validate the developed method, certified reference materials (SLRS-4 Riverine water) and human serum (Sero-M10181) were analyzed. The resulting data indicated a non-significant difference in obtained and certified values of Cu(2+). The developed procedure was successfully applied for the preconcentration and determination of trace levels of Cu(2+) in environmental and biological samples.

  14. Investigation of the local structure of mixtures of an ionic liquid with polar molecular species through molecular dynamics: cluster formation and angular distributions.

    PubMed

    Carrete, Jesús; Méndez-Morales, Trinidad; Cabeza, Óscar; Lynden-Bell, Ruth M; Gallego, Luis J; Varela, Luis M

    2012-05-24

    In this work, we used molecular dynamics simulations to analyze in detail the spatial distributions of the different constituents in mixtures of 1-butyl-3-methylimidazolium tetrafluoroborate with three polar molecular species: water and two alcohols of different chain lengths (methanol and ethanol). In particular, we report results regarding the influence of the chosen species and its concentration on the formation of ionic and molecular clusters over the whole miscibility range, as well as on the angular distribution of polar molecules around the anion and the cation in these systems. Both analyses showed that addition of a molecular species breaks down the polar network of the pure ionic liquid in clusters whose mean size decreases progressively as more molecules are added. At very high concentrations of the molecular species, the ions are found to be isolated in mixtures with water and methanol, but they tend to form pairs in ethanol. In mixtures with water we identified large clusters that form a water network at very high water concentrations, while at low water concentrations polar molecules tend to form smaller aggregates. In contrast, in mixtures with alkanols there is no evidence of the formation of large alcohol clusters at any concentration. Spatial order in alcohol was also studied by means of the Kirkwood G factor, reaching the conclusion that the angular correlations which appear in pure alcohols due to dipole interactions are destroyed by the ionic liquid, even when present only in tiny amounts.

  15. Molar conductivity behavior of ionic liquid compare to inorganic salt in electrolyte solution at ambien temperature

    NASA Astrophysics Data System (ADS)

    Hanibah, H.; Hashim, N. Z. Nor; Shamsudin, I. J.

    2017-09-01

    Molar Conductivity (Λ) behaviour of 1-butyl-3-methylimidazolium (Bmin) acetate and Bmin chloride (Bmin Cl) ionic liquids compared to lithium perchlorate (LiClO4) has been studied in aqueous and acetonitrile (ACN) solution at ambient temperature. The limiting molar conductivity (Λ0) was obtained using the Kohlrausch's and Ostwald's equation for the investigated systems. The results show that the Λ0 value for LiClO4 in both aqueous or acetonitrile (ACN) electrolyte system with a highest value as compare to ionic liquid electrolyte systems. This might as a result of ions association of LiClO4 in aqueous medium as the concentration of the solute increases in the solvent. In addition, the partial dissociation behaviour of LiClO4 in less polar solvent such as ACN also significantly affects the Λ0 value for this electrolyte system. However, for Bmin acetate and Bmin Cl in the aqueous or ACN medium show a much lower Λ0 value as compare to LiClO4 electrolyte system, 45.64, 74.63 and 107.32 S cm2 mol-1 respectively. This as a result of the nature behaviour of ionic liquid itself that present as free moving ions at room temperature before any dissolution into the solvent. In addition, a vice versa trend of Λ0 value is noted for Bmin acetate and Bmin Cl, 21.34 and 14.56 S cm2 mol-1 respectively in ACN electrolyte system. This indicated the solvent and the size of the anion play an important role in the estimation of limiting molar conductivity values which significantly affect the present of total free moving ions in an electrolyte system.

  16. Development of OPLS-AA Force Field Parameters for 68 Unique Ionic Liquids.

    PubMed

    Sambasivarao, Somisetti V; Acevedo, Orlando

    2009-04-14

    OPLS-AA force field parameters have been developed and validated for use in the simulation of 68 unique combinations of room temperature ionic liquids featuring 1-alkyl-3-methylimidazolium [RMIM] (R = Me, Et, Bu, Hex, Oct), N-alkylpyridinium [RPyr], and choline cations, along with Cl(-), PF6(-), BF4(-), NO3(-), AlCl4(-), Al2Cl7(-), TfO(-), saccharinate, and acesulfamate anions. The new parameters were fit to conformational profiles from gas-phase ab initio calculations at the LMP2/cc-pVTZ(-f)//HF/6-31G(d) theory level and compared to experimental condensed-phase structural and thermodynamic data. Monte Carlo simulations of the ionic liquids gave relative deviations from experimental densities of ca. 1-3% at 25 °C for most combinations and also yielded close agreement over a temperature range of 5 to 90 °C. Predicted heats of vaporization compared well with available experimental data and estimates. Transferability of the new parameters to multiple alkyl side-chain lengths for [RMIM] and [RPyr] was determined to give excellent agreement with charges and torsion potentials developed specific to desired alkyl lengths in 35 separate ionic liquid simulations. As further validation of the newly developed parameters, the Kemp elimination reaction of benzisoxazole via piperidine was computed in 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6] using mixed quantum and molecular mechanics (QM/MM) simulations and was found to give close agreement with the experimental free energy of activation.

  17. Influence of ionic association, transport properties, and solvation on the catalytic hydrogenation of 1,3-cyclohexadiene in ionic liquids.

    PubMed

    Podgoršek, Ajda; Salas, Gorka; Campbell, Paul S; Santini, Catherine C; Pádua, Agílio A H; Costa Gomes, Margarida F; Fenet, Bernard; Chauvin, Yves

    2011-10-27

    The influence of the nature of two different ionic liquids, namely 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [C(1)C(4)Im][NTf(2)], and 1-butyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide, [C(1)C(1)C(4)Im][NTf(2)], on the catalytic hydrogenation of 1,3-cyclohexadiene with [Rh(COD)(PPh(3))(2)][NTf(2)] (COD = 1,5-cyclooctadiene) was studied. Initially, the effect of different concentrations of 1,3-cyclohexadiene on the molecular interactions and on the structure in two ionic liquids was investigated by NMR and by molecular dynamic simulations. It was found that in both ionic liquids 1,3-cyclohexadiene is solvated preferentially in the lipophilic regions. Furthermore, the higher solubility of 1,3-cyclohexadiene in [C(1)C(4)Im][NTf(2)] and the smaller positive values of the excess molar enthalpy of mixing for the 1,3-cyclohexadiene + [C(1)C(4)Im][NTf(2)] system in comparison with 1,3-cyclohexadiene + [C(1)C(1)C(4)Im][NTf(2)] indicate more favorable interactions between 1,3-cyclohexadiene and the C(1)C(4)Im(+) cation than with the C(1)C(1)C(4)Im(+) cation. Subsequently, diffusivity and conductivity measurements of the 1,3-cyclohexadiene + ionic liquid mixtures at different compositions allowed a characterization of mass and charge transport in the media and access to the ionicity of ionic liquids in the mixture. From the dependence of the ratio between molar conductivity and the conductivity inferred from NMR diffusion measurements, Λ(imp)/Λ(NMR), on concentration of 1,3-cyclohexadiene in the ionic liquid mixture, it was found that increasing the amount of 1,3-cyclohexadiene leads to a decrease in the ionicity of the medium. Finally, the reactivity of the catalytic hydrogenation of 1,3-cyclohexadiene using [Rh(COD)(PPh(3))(2)][NTf(2)] performed in [C(1)C(4)Im][NTf(2)] at different compositions of 1,3-cyclohexadiene and in [C(1)C(1)C(4)Im][NTf(2)] at one composition was related linearly to the viscosity, hence the reaction rate is

  18. Development of an ionic liquid-based microwave-assisted method for simultaneous extraction and distillation for determination of proanthocyanidins and essential oil in Cortex cinnamomi.

    PubMed

    Liu, Ye; Yang, Lei; Zu, Yuangang; Zhao, Chunjian; Zhang, Lin; Zhang, Ying; Zhang, Zhonghua; Wang, Wenjie

    2012-12-15

    Cortex cinnamomi is associated with many health benefits and is used in the food and pharmaceutical industries. In this study, an efficient ionic liquid-based microwave-assisted simultaneous extraction and distillation (ILMSED) technique was used to extract cassia oil and proanthocyanidins from Cortex cinnamomi; these were quantified by gas chromatography/mass spectrometry (GC-MS) and the vanillin-HCl colorimetric method, respectively. 0.5M 1-butyl-3-methylimidazolium bromide ionic liquid was selected as solvent. The optimum parameters of dealing with 20.0 g sample were 230 W microwave irradiation power, 15 min microwave extraction time and 10 liquid-solid ratio. The yields of essential oil and proanthocyanidins were 1.24 ± 0.04% and 4.58 ± 0.21% under the optimum conditions. The composition of the essential oil was analysed by GC-MS. Using the ILMSED method, the energy consumption was reduced and the extraction yields were improved. The proposed method was validated using stability, repeatability, and recovery experiments. The results indicated that the developed ILMSED method provided a good alternative for the extraction of both the essential oil and proanthocyanidins from Cortex cinnamomi. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Optimization of Ionic Liquid Based Simultaneous Ultrasonic- and Microwave-Assisted Extraction of Rutin and Quercetin from Leaves of Velvetleaf (Abutilon theophrasti) by Response Surface Methodology

    PubMed Central

    Zhao, Chunjian; Lu, Zhicheng; He, Xin; Li, Zhao; Shi, Kunming; Yang, Lei; Fu, Yujie; Zu, Yuangang

    2014-01-01

    An ionic liquids based simultaneous ultrasonic and microwave assisted extraction (ILs-UMAE) method has been proposed for the extraction of rutin (RU), quercetin (QU), from velvetleaf leaves. The influential parameters of the ILs-UMAE were optimized by the single factor and the central composite design (CCD) experiments. A 2.00 M 1-butyl-3-methylimidazolium bromide ([C4mim]Br) was used as the experimental ionic liquid, extraction temperature 60°C, extraction time 12 min, liquid-solid ratio 32 mL/g, microwave power of 534 W, and a fixed ultrasonic power of 50 W. Compared to conventional heating reflux extraction (HRE), the RU and QU extraction yields obtained by ILs-UMAE were, respectively, 5.49 mg/g and 0.27 mg/g, which increased, respectively, 2.01-fold and 2.34-fold with the recoveries that were in the range of 97.62–102.36% for RU and 97.33–102.21% for QU with RSDs lower than 3.2% under the optimized UMAE conditions. In addition, the shorter extraction time was used in ILs-UMAE, compared with HRE. Therefore, ILs-UMAE was a rapid and an efficient method for the extraction of RU and QU from the leaves of velvetleaf. PMID:25243207

  20. Renewable feedstocks in green solvents: thermodynamic study on phase diagrams of D-sorbitol and xylitol with dicyanamide based ionic liquids.

    PubMed

    Paduszyński, Kamil; Okuniewski, Marcin; Domańska, Urszula

    2013-06-13

    Experimental and theoretical studies on thermodynamic properties of three ionic liquids based on dicyanamide anion (namely, 1-butyl-3-methylimidazolium dicyanamide, 1-butyl-1-methylpyrrolidinium dicyanamide, and 1-butyl-1-methylpiperidinium dicyanamide) and their binary mixtures with sugar alcohols (D-sorbitol and xylitol) were conducted in order to assess the applicability of the salts ionic liquids for dissolution of those biomass-related materials. Density and dynamic viscosity (at ambient pressure) of pure ionic liquids are reported in the temperature range from T = 293.15 to 363.15 K. Solid-liquid equilibrium phase diagrams in binary systems {sugar alcohol + ionic liquid} were measured with dynamic method up to the fusion temperature of sugar alcohol. The impact of the chemical structure of both the ionic liquid and sugar alcohol were established and discussed. For the very first time, the experimental solubility data were reproduced and analyzed in terms of equation of state rooted in statistical mechanics. For this purpose, perturbed-chain statistical associating fluid theory (PC-SAFT) was employed. In particular, new molecular schemes for the ionic liquids, D-sorbitol, and xylitol were proposed, and then the pure chemicals were parametrized by using available density and vapor pressure data. The model allowed accurate correlation of pure fluid properties for both ionic liquids and sugar alcohols, when the association term is taken into account. The results of solid-liquid equilibria modeling were also satisfactory. However, one or two adjustable binary corrections to the adopted combining rules were required to be adjusted in order to accurately capture the phase behavior. It was shown that a consistent thermodynamic description of extremely complex systems can be achieved by using relatively simple (but physically grounded) theoretical tools and molecular schemes.

  1. Water-free rare-earth-metal ionic liquids/ionic liquid crystals based on hexanitratolanthanate(III) anion.

    PubMed

    Ji, Shun-Ping; Tang, Meng; He, Ling; Tao, Guo-Hong

    2013-04-02

    The hexanitratolanthanate anion (La(NO(3))(6)(3-)) is an interesting symmetric anion suitable to construct the component of water-free rare-earth-metal ionic liquids. The syntheses and structural characterization of eleven lanthanum nitrate complexes, [C(n)mim](3)[La(NO(3))(6)] (n=1, 2, 4, 6, 8, 12, 14, 16, 18), including 1,3-dimethylimidazolium hexanitratolanthanate ([C(1)mim](3)[La(NO(3))(6)], 1), 1-ethyl-3-methylimidazolium hexanitratolanthanate ([C(2)mim](3)[La(NO(3))(6)], 2), 1-butyl-3-methylimidazolium hexanitratolanthanate ([C(4)mim](3)[La(NO(3))(6)], 3), 1-isobutyl-3-methylimidazolium hexanetratolanthanate ([isoC(4)mim](3)[La(NO(3))(6)], 4), 1-methyl-3-(3'-methylbutyl)imidazolium hexanitratolanthanate ([MC(4)mim](3)[La(NO(3))(6)], 5), 1-hexyl-3-methylimidazolium hexanitratolanthanate ([C(6)mim](3)[La(NO(3))(6)], 6), 1-methyl-3-octylimidazolium hexanitratolanthanate ([C(8)mim](3)[La(NO(3))(6)], 7), 1-dodecyl-3-methylimidazolium hexanitratolanthanate ([C(12)mim](3)[La(NO(3))(6)], 8), 1-methyl-3-tetradecylimidazolium hexanitratolanthanate ([C(14)mim](3)[La-(NO(3))(6)], 9), 1-hexadecyl-3-methylimid-azolium hexanitratolanthanum ([C(16)dmim](3)[La(NO(3))(6)], 10), and 1-methyl-3-octadecylimidazolium hexanitratolanthanate ([C(18)mim](3)[La(NO(3))(6)], 11) are reported. All new compounds were characterized by (1)H and (13)C NMR, and IR spectroscopy as well as elemental analysis. The crystal structure of compound 1 was determined by using single-crystal X-ray diffraction, giving the following crystallographic information: monoclinic; P2(1)/c; a=15.3170 (3), b=14.2340 (2), c=13.8954(2) Å; β=94.3453(15)°, V=3020.80(9) Å(3), Z=4, ρ=1.764 g cm(-3). The coordination polyhedron around the lanthanum ion is rationalized by six nitrate anions with twelve oxygen atoms. No hydrogen-bonding network or water molecule was found in 1. The thermodynamic stability of the new complexes was investigated by using thermogravimetric analysis (TGA). The water

  2. Ionic liquid-based single drop microextraction of ultra-trace copper in food and water samples before spectrophotometric determination.

    PubMed

    Wen, Xiaodong; Deng, Qingwen; Guo, Jie

    2011-09-01

    In this work, room temperature ionic liquid (RTIL) 1-butyl-3-methylimidazolium hexafluorophosphate ([C4mim]PF6) was used as extractant in single drop microextraction (SDME). The traditionally volatile organic extractants were substituted by this green reagent, which changed SDME preconcentration into environmentally friendly method, relatively. After this pretreatment, ultra-trace copper in water and food samples could be accurately detected by spectrophotometer. This study was focused on the improvement of the analytical performance of spectrophotometric determination, expanding its applications. The influence factors relevant to IL-SDME, such as absorption spectra of complex, drop volume of RTIL, stirring rate and time, concentration of chelating agent, pH, and salt effect were studied systematically. Under the optimal conditions, the limit of detection (LOD) was 0.15 μg L(-1) with an enhancement factor (EF) of 33. The proposed method was green, simple, rapid, sensitive, and cost-efficient. Copyright © 2011 Elsevier B.V. All rights reserved.

  3. Charging and aggregation of latex particles in aqueous solutions of ionic liquids: towards an extended Hofmeister series.

    PubMed

    Oncsik, Tamas; Desert, Anthony; Trefalt, Gregor; Borkovec, Michal; Szilagyi, Istvan

    2016-03-14

    The effect of ionic liquid (IL) constituents and other monovalent salts on the stability of polystyrene latex particles was studied by electrophoresis and light scattering in dilute aqueous suspensions. The surface charge and the aggregation rate were both sensitive to the type of ion leading to different critical coagulation concentration (CCC) values. Systematic variation of the type of IL cation and anion allows us to place these ions within the Hofmeister series. We find that the dicyanoamide anion should be placed between iodide and thiocyanate, while all 1-alkyl-3-methylimidazolium cations can be positioned to the left of the tetramethylammonium and ammonium ions. The hydrophobicity of the 1-butyl-1-methylpyrrolidinium (BMPL(+)) ion is intermediate between 1-ethyl-3-methylimidazolium (EMIM(+)) and 1-butyl-3-methylimidazolium (BMIM(+)). With increasing alkyl chain length, the 1-alkyl-3-methylimidazolium cations adsorb on the latex particles very strongly, and 1-hexyl-3-methylimidazolium (HMIM(+)) and 1-octyl-3-methylimidazolium (OMIM(+)) lead to pronounced charge reversal and to an intermediate restabilization region.

  4. Dissolution of the rare-earth mineral bastnaesite by acidic amide ionic liquid for recovery of critical

    SciTech Connect

    Dai, Sheng; Freiderich, John W.; Luo, Huimin; Moyer, Bruce A.; Stankovich, Joseph J.

    2015-08-19

    Rare-earth elements provide the cornerstones to clean sustainable energy and modern technologies such as computers, communications, and transportation. As such, the recovery of rare earths (REs) from minerals such as bastnaesite remains important for modern times. As the light lanthanides (La–Nd) constitute the majority (typically > 98.7 %) of the REs in bastnaesite with the heavy REs (Sm–Lu) contributing the remainder (approximately 1.3 %), an enrichment of heavier REs may serve as an effective means of assisting rare-earth recovery. Such an extractive metallurgy process involving ionic liquids (ILs) leads to an enrichment of heavy REs by nearly an order of magnitude. The acidic IL N,N-dimethylacetamidium bis(trifluoromethylsulfonyl)imide (DMAH+NTf2) in the IL 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMIM+NTf2) dissolves froth flotation bastnaesite, synthetic bastnaesite analogues (RECO3F), RE2O3, and RE2(CO3)3 minerals. Furthermore, an overall reaction for the dissolution of bastnaesite is proposed for this IL system. This IL system may provide the initial stages of a greater RE separation scheme for bastnaesite froth flotation concentrates.

  5. Surface structures of equimolar mixtures of imidazolium-based ionic liquids using high-resolution Rutherford backscattering spectroscopy

    NASA Astrophysics Data System (ADS)

    Nakajima, Kaoru; Oshima, Shinichi; Suzuki, Motofumi; Kimura, Kenji

    2012-11-01

    Surface structures of equimolar mixtures of imidazolium-based ionic liquids (ILs) having a common cation (1-butyl-3-methylimidazolium ([C4MIM]) or 1-hexyl-3-methylimidazolium ([C6MIM])) and different anions (bis(trifluoromethanesulfonyl)imide ([TFSI]), hexafluorophosphate ([PF6]) or chlorine) are studied using high-resolution Rutherford backscattering spectroscopy (HRBS). Both cations and anions have the same preferential orientations at the surface as in the pure ILs. In the mixture, the larger anion is located shallower than the smaller anion. The [TFSI] anion is slightly enriched at the surface relative to [PF6] with coverage of ~ 60% for the equimolar mixtures of [C4(6)MIM] [TFSI] and [C4(6)MIM] [PF6]. No surface segregation is observed for [C6MIM] [TFSI]0.5[Cl]0.5 and [C6MIM] [PF6]0.5[Cl]0.5. These results are different from the recent TOF-SIMS measurement where very strong surface segregation of [TFSI] was concluded for the mixture of [C4MIM] [TFSI] and [C4MIM] [PF6].

  6. Multi-podant diglycolamides and room temperature ionic liquid impregnated resins: An excellent combination for extraction chromatography of actinides.

    PubMed

    Gujar, R B; Ansari, S A; Verboom, W; Mohapatra, P K

    2016-05-27

    Extraction chromatography resins, prepared by impregnating two multi-podant diglycolamide ligands, viz. diglycolamide-functionalized calix[4]arene (C4DGA) and tripodal diglycolamide (T-DGA) dissolved in the room temperature ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide (RTIL: C4mimTf2N) on Chromosorb-W (an inert solid support), gave excellent results for the removal of trivalent actinides from acidic waste solutions. Distribution coefficient measurements on several metal ions showed selective sorption of Am(III) over hexavalent uranyl ions and other fission product elements such as strontium and cesium. The sorbed metal ions could be efficiently desorbed with a complexing solution containing guanidine carbonate and EDTA buffer. The sorption of Am(III) on both resins followed pseudo-second order rate kinetics with rate constants of 1.37×10(-6) and 6.88×10(-7)g/cpmmin for T-DGA and C4DGA resins, respectively. The metal sorption on both resins indicated the Langmuir monolayer chemisorption phenomenon with Eu(III) sorption capacities of 4.83±0.21 and 0.52±0.05mg per g of T-DGA and C4DGA resins, respectively. The results of column studies show that these resins are of interest for a possible application for the recovery of hazardous trivalent actinides from dilute aqueous solutions.

  7. Enhanced hydrolysis of bamboo biomass by chitosan based solid acid catalyst with surfactant addition in ionic liquid.

    PubMed

    Si, Wenqing; Li, Yichen; Zheng, Jie; Wei, Shun'an; Wang, Dan

    2017-10-15

    Surfactants were used for the hydrolysis of bamboo biomass to enhance lignocellulose hydrolysis. Tween 80, polyethylene glycol 4000 (PEG 4000), and sodium dodecyl sulfate (SDS) were tested as surfactants for improving the bamboo hydrolysis with a novel sulfonated cross-linked chitosan solid acid catalyst (SCCAC) in ionic liquid (IL). Compared to the use of only SCCAC in 1-Butyl-3-methylimidazolium chloride ([BMIM]Cl), the surfactants facilitated hydrolysis and improved the yield of total reducing sugar (TRS) under the same conditions. Tween 80 was the most effective surfactant, with a TRS yield of 68.01% achieved at 120°C after 24h. Surfactants broke the lignocellulose structure, promoted lignin removal, and increased positive interactions between cellulose and the catalyst, which were favorable for hydrolysis. This novel surfactant-assisted hydrolysis strategy with SCCAC and IL as the solvent demonstrated a promise for the large-scale transformation of biomass into biofuels and bioproducts. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Octadecyltrichlorosilane (OTS)-coated ionic liquid drops: Micro-reactors for homogenous catalytic reactions at designated interfaces.

    PubMed

    Zhang, Xiaoning; Cai, Yuguang

    2012-01-01

    An ionic liquid (IL), 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) can assemble on prefabricated carboxylic acid-terminated chemical patterns on octadecyltrichlorosilane (OTS) film. The chemical pattern controls the position, shape and size of the IL on the surface. After the IL assembly - by incubating IL drops assembled on sample surface in an OTS silane vapor - an OTS layer was coated on the IL drop surface which encapsulated the IL drop. The OTS-coated capsule can exist stably under aqueous solution. The OTS coating protected the IL drops from being instantaneously dissolved by other solutions. We found that a homogenous catalyst (FeCl(3)) dissolved in [Bmim]Cl can be assembled together on the chemical patterns and subsequently encapsulated together with [Bmim]Cl by OTS coating. The pinhole defects within the vapor-coated silane layer provide space for the catalyst inside the capsule and reactants outside the capsule to meet and react. When the OTS-coated capsule containing a FeCl(3)/IL mixture was soaked under H(2)O(2) solution, the Fe(3+) ions catalyzed the decomposition reaction of hydrogen peroxide at the vapor-coated OTS-water interface. Since the shape and position of the interface is defined by the underneath chemical pattern, our findings show that the OTS-coated IL drops assembled on chemical patterns can be used as novel micro-reactors. This allows homogenous catalytic reactions to occur at the designated interfaces.

  9. Dielectric spectroscopy study on ionic liquid microemulsion composed of water, TX-100, and BmimPF6

    NASA Astrophysics Data System (ADS)

    Chen, Zhen; Nozaki, Ryusuke

    2012-06-01

    We report here a broadband dielectric spectroscopy study on an ionic liquid microemulsion (ILM) composed of water, Triton X-100 (TX-100), and 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF6). It is found that the phase behavior of this ILM can be easily identified by its dielectric response. The dielectric behavior of the ILM in the GHz range is consistent with that of TX-100/water mixtures with comparable water-to-TX-100 weight ratio. It consists of the relaxations due to ethylene oxide (EO) unit relaxation, hydration water dynamics, and/or free water dynamics. The water content dependence of the EO unit relaxation suggests that this relaxation involves dynamics of hydration water molecules. In the IL-in-water microemulsion phase, it is found that bmimPF6 molecules are preferentially dissolved in water when their concentration in water is lower than the solubility. An additional dielectric relaxation that is absent in the TX-100/water mixtures is observed in the frequency range of 107-108 Hz for this ILM. This low-frequency relaxation is found closely related to the bmimPF6 molecule and could be attributed to the hopping of its cations/anions between the anionic/cationic sites.

  10. Facile synthesis of nitrogen and sulfur codoped carbon from ionic liquid as metal-free catalyst for oxygen reduction reaction.

    PubMed

    She, Yiyi; Lu, Zhouguang; Ni, Meng; Li, Li; Leung, Michael K H

    2015-04-08

    Developing metal-free catalysts for oxygen reduction reaction (ORR) is a great challenge in the development of fuel cells. Nitrogen and sulfur codoped carbon with remarkably high nitrogen content up to 13.00 at % was successfully fabricated by pyrolysis of homogeneous mixture of exfoliated graphitic flakes and ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([Bimi][Tf2N]). The exfoliated graphite flakes served as a structure-directing substance as well as additional carbon source in the fabrication. It was demonstrated that the use of graphite flakes increased the nitrogen doping level, optimized the composition of active nitrogen configurations, and enlarged the specific surface area of the catalysts. Electrochemical characterizations revealed that the N and S codoped carbon fabricated by this method exhibited superior catalytic activities toward ORR under both acidic and alkaline conditions. Particularly in alkaline solution, the current catalyst compared favorably to the conventional 20 wt % Pt/C catalyst via four-electron transfer pathway with better ORR selectivity. The excellent catalytic activity was mainly ascribed to high nitrogen doping content, appropriate constitution of active nitrogen configurations, large specific surface area, and synergistic effect of N and S codoping.

  11. Enhancement in ionic liquid tolerance of cellulase immobilized on PEGylated graphene oxide nanosheets: Application in saccharification of lignocellulose.

    PubMed

    Xu, Jiaxing; Sheng, Zhenhuan; Wang, Xinfeng; Liu, Xiaoyan; Xia, Jun; Xiong, Peng; He, Bingfang

    2016-01-01

    The objective of the present work was to improve ionic liquid (IL) tolerance of cellulase based on the exploration of functional nanoscale carriers for potential application in lignocellulosic biorefinery. PEGylated graphene oxide (GO) composite was successfully fabricated by chemical binding of 4-arm-PEG-NH2 and GO and applied to the immobilization of cellulase. The PEGylated GO-Cellulase retained 61% of the initial activity in 25% (w/v) 1-butyl-3-methylimidazolium chloride ([Bmim][Cl]) while free cellulase only retained 2%. The IL stability was enhanced more than 30 times. The relatively minor change in Km value (from 2.7 to 3.2mgmL(-1)) after the immobilization suggested that PEGylated GO-Cellulase was capable of closely mimicking the performance of free enzyme. After treating rice straw with [Bmim][Cl] and dilution to a final IL concentration of 15% (w/v), the slurry was directly hydrolyzed using PEGylated GO-Cellulase without IL removing and a high hydrolysis rate of 87% was achieved. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Effect of a room-temperature ionic liquid on the structure and properties of electrospun poly(vinylidene fluoride) nanofibers.

    PubMed

    Xing, Chenyang; Guan, Jipeng; Li, Yongjin; Li, Jingye

    2014-03-26

    Novel anti-static nanofibers based on blends of poly(vinylidene fluoride) (PVDF) and a room-temperature ionic liquid (RTIL), 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6], were fabricated using an electrospinning approach. The effects of the RTIL on the morphology, crystal structure, and physical properties of the PVDF nanofibers were investigated. Incorporation of RTIL leads to an increase in the mean fiber diameter and the rough fiber surface of the PVDF/RTIL composite nanofibers compared with the neat PVDF nanofibers. The PVDF in the PVDF/RTIL nanofibers exhibits an extremely high content (almost 100%) of β crystals, in contrast to the dominance of PVDF γ crystals in bulk melt-blended PVDF/RTIL blends. Nonwoven fabrics produced from the electrospun PVDF/RTIL composite nanofibers show better stretchability and higher electrical conductivity than those made from neat PVDF without RTIL, and are thus excellent antielectrostatic fibrous materials. In addition, RTIL greatly improved the hydrophobicity of the PVDF fibers, enabling them to effectively separate a mixture of tetrachloromethane (CCl4) and water. The extremely high β content, excellent antielectrostatic properties, better stretchability, and hydrophobicity of the present PVDF/RTIL nanofibers make them a promising candidate for micro- and nanoscale electronic device applications.

  13. Acidic Zeolite L as a Highly Efficient Catalyst for Dehydration of Fructose to 5-Hydroxymethylfurfural in Ionic Liquid.

    PubMed

    Ma, Zhongsen; Hu, Hualei; Sun, Zhongqiang; Fang, Wenting; Zhang, Jian; Yang, Longfei; Zhang, Yajie; Wang, Lei

    2017-04-22

    Zeolite L was synthesized by the hydrothermal method and post-treated by NH4 exchange to adjust its acidity. The samples were systematic characterized by various techniques including XRD, X-ray fluorescence spectroscopy, N2 adsorption-desorption, scanning electron microscopy, pyridine IR spectroscopy, and NH3 temperature-programmed desorption. The results demonstrated that the NH4 -exchange post-treatment increased the surface area, micropore volume, and acidity of zeolite L. The catalytic performance of the samples was tested in the dehydration of fructose to 5-hydroxymethylfurfural (HMF) in ionic liquid (1-butyl-3-methylimidazolium bromide, [bmim]Br). 99.1 % yield of HMF was obtained when the KL-80 °C-1 h sample (KL zeolite treated with 1 m NH4 NO3 solution at 80 °C for 1 h) was used. The high efficiency could be attributed to the appropriate acid properties of the catalyst. The zeolite catalyst could be reused four times without significant decrease in activity. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. A novel support for laccase immobilization: cellulose acetate modified with ionic liquid and application in biosensor for methyldopa detection.

    PubMed

    Moccelini, Sally K; Franzoi, Ana C; Vieira, Iolanda C; Dupont, Jairton; Scheeren, Carla W

    2011-04-15

    A material based on cellulose acetate (CA) and the room temperature ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMI·N(Tf)(2)) was developed and characterized by scanning electron microscopy, electron dispersive spectroscopy and infrared analysis. Laccase (Lac) from Aspergillus oryzae was immobilized in this material to investigate the behavior of methyldopa by square-wave voltammetry. Under optimized conditions, the Lac biosensor based on CA/BMI·N(Tf)(2) exhibited an excellent electrocatalytic performance: the analytical curve showed good linear range for methyldopa concentrations from 34.8 to 370.3 μM with a detection limit of 5.5 μM. This sensor demonstrated acceptable stability (ca. 60 days; at least 350 determinations), good repeatability and reproducibility (relative standard deviations of 1.5 and 4.3%, respectively). The recovery study of methyldopa in pharmaceutical formulations ranged from 94.1 to 105.9%. The determination of this substance using the biosensor compared favorably with that using a spectrophotometry procedure at the 95% confidence level, and indicated potential application to methyldopa determination in pharmaceutical samples.

  15. Unusual solvatochromic absorbance probe behaviour within mixtures of poly(ethylene glycol)-400 + ionic liquid, [bmim][Tf2N

    NASA Astrophysics Data System (ADS)

    Ali, Anwar; Ali, Maroof; Malik, Nisar Ahmad; Uzair, Sahar

    2014-03-01

    The potentially green solvents made up of ionic liquids (ILs) and poly(ethylene glycols) may have wide range of the applications in many chemical and biochemical fields. In the present work, solvatochromic absorbance probe behaviour is used to assess the physicochemical properties of the mixtures composed of PEG-400 + IL, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [bmim][Tf2N]. Lowest energy intramolecular charge-transfer absorbance maxima of a betaine dye, i.e., ETN , indicates the dipolarity/polarizability and/or hydrogen-bond donating (HBD) acidity of the [bmim][Tf2N] + PEG-400 mixtures to be even higher than that of neat [bmim][Tf2N], the solution component with higher dipolarity/polarizability and/or HBD acidity. Dipolarity/polarizability (π∗) obtained separately from the electronic absorbance response of probe N,N-diethyl-4-nitroaniline, and the HBD acidity (α) of PEG-400 + [bmim][Tf2N] mixtures are also observed to be anomalously high. A comparative study of the PEG + IL mixtures has also been done with PEG-400 + molecular organic solvents (protic polar [methanol], aprotic polar [N,N-dimethylformamide], and non polar, [benzene]) mixtures, but these mixtures do not show this type of unusual behaviour. A four-parameter simplified combined nearly ideal binary solvent/Redlich-Kister (CNIBS/R-K) equation is shown to satisfactorily predict the solvatochromic parameters within PEG-400 + different solvent mixtures.

  16. Synthesis of Cu, Zn and Cu/Zn brass alloy nanoparticles from metal amidinate precursors in ionic liquids or propylene carbonate with relevance to methanol synthesis

    NASA Astrophysics Data System (ADS)

    Schütte, Kai; Meyer, Hajo; Gemel, Christian; Barthel, Juri; Fischer, Roland A.; Janiak, Christoph

    2014-02-01

    Microwave-induced decomposition of the transition metal amidinates {[Me(C(NiPr)2)]Cu}2 (1) and [Me(C(NiPr)2)]2Zn (2) in the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF4]) or in propylene carbonate (PC) gives copper and zinc nanoparticles which are stable in the absence of capping ligands (surfactants) for more than six weeks. Co-decomposition of 1 and 2 yields the intermetallic nano-brass phases β-CuZn and γ-Cu3Zn depending on the chosen molar ratios of the precursors. Nanoparticles were characterized by high-angle annular dark field-scanning transmission electron microscopy (HAADF-STEM), dynamic light scattering and powder X-ray diffractometry. Microstructure characterizations were complemented by STEM with spatially resolved energy-dispersive X-ray spectrometry and X-ray photoelectron spectroscopy. Synthesis in ILs yields significantly smaller nanoparticles than in PC. β-CuZn alloy nanoparticles are precursors to catalysts for methanol synthesis from the synthesis gas H2/CO/CO2 with a productivity of 10.7 mol(MeOH) (kg(Cu) h)-1.Microwave-induced decomposition of the transition metal amidinates {[Me(C(NiPr)2)]Cu}2 (1) and [Me(C(NiPr)2)]2Zn (2) in the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF4]) or in propylene carbonate (PC) gives copper and zinc nanoparticles which are stable in the absence of capping ligands (surfactants) for more than six weeks. Co-decomposition of 1 and 2 yields the intermetallic nano-brass phases β-CuZn and γ-Cu3Zn depending on the chosen molar ratios of the precursors. Nanoparticles were characterized by high-angle annular dark field-scanning transmission electron microscopy (HAADF-STEM), dynamic light scattering and powder X-ray diffractometry. Microstructure characterizations were complemented by STEM with spatially resolved energy-dispersive X-ray spectrometry and X-ray photoelectron spectroscopy. Synthesis in ILs yields significantly smaller nanoparticles than in PC.

  17. Microwave irradiation for the facile synthesis of transition-metal nanoparticles (NPs) in ionic liquids (ILs) from metal-carbonyl precursors and Ru-, Rh-, and Ir-NP/IL dispersions as biphasic liquid-liquid hydrogenation nanocatalysts for cyclohexene.

    PubMed

    Vollmer, Christian; Redel, Engelbert; Abu-Shandi, Khalid; Thomann, Ralf; Manyar, Haresh; Hardacre, Christopher; Janiak, Christoph

    2010-03-22

    Stable chromium, molybdenum, tungsten, manganese, rhenium, ruthenium, osmium, cobalt, rhodium, and iridium metal nanoparticles (M-NPs) have been reproducibly obtained by facile, rapid (3 min), and energy-saving 10 W microwave irradiation (MWI) under an argon atmosphere from their metal-carbonyl precursors [M(x)(CO)(y)] in the ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF(4)]). This MWI synthesis is compared to UV-photolytic (1000 W, 15 min) or conventional thermal decomposition (180-250 degrees C, 6-12 h) of [M(x)(CO)(y)] in ILs. The MWI-obtained nanoparticles have a very small (<5 nm) and uniform size and are prepared without any additional stabilizers or capping molecules as long-term stable M-NP/IL dispersions (characterization by transmission electron microscopy (TEM), transmission electron diffraction (TED), and dynamic light scattering (DLS)). The ruthenium, rhodium, or iridium nanoparticle/IL dispersions are highly active and easily recyclable catalysts for the biphasic liquid-liquid hydrogenation of cyclohexene to cyclohexane with activities of up to 522 (mol product) (mol Ru)(-1) h(-1) and 884 (mol product) (mol Rh)(-1) h(-1) and give almost quantitative conversion within 2 h at 10 bar H(2) and 90 degrees C. Catalyst poisoning experiments with CS(2) (0.05 equiv per Ru) suggest a heterogeneous surface catalysis of Ru-NPs.

  18. Infrared studies of PVC-based electrolytes incorporated with lithium triflate and 1-butyl-3-methyl imidazolium trifluoromethanesulfonate as ionic liquid

    NASA Astrophysics Data System (ADS)

    Zulkepeli, Nik A. S. Nik; Winie, Tan; Subban, R. H. Y.

    2017-09-01

    In this work, 1-butyl-3-methylimidazolium trifluoromethanesulfonate (BMIMCF3SO3) is employed as ionic liquid in PVC-based polymer electrolyte system with lithium triflate (LiCF3SO3) as doping salt. The samples in film form were prepared by quantitatively varying the concentration of BMIMCF3SO3 to a fixed ratio of PVC-LiCF3SO3 using solution cast technique. The highest room temperature ionic conductivity of 1.120 × 10-7 Scm-1 was exhibited by PVC-LiCF3SO3-BMIMCF3SO3 containing 3 wt. % BMIMCF3SO3. FTIR spectra of the polymer electrolytes were examined to study the complexation of the PVC-based polymer electrolytes. Intensity of free ions, ion pairs, and ion aggregates were obtained from FTIR deconvolution in an attempt to correlate with ionic conductivity results. The intensity of free ions was found to be high for sample with 3 wt. % BMIMCF3SO3.

  19. Sulfonic Acid- and Lithium Sulfonate-Grafted Poly(Vinylidene Fluoride) Electrospun Mats As Ionic Liquid Host for Electrochromic Device and Lithium-Ion Battery.

    PubMed

    Zhou, Rui; Liu, Wanshuang; Leong, Yew Wei; Xu, Jianwei; Lu, Xuehong

    2015-08-05

    Electrospun polymer nanofibrous mats loaded with ionic liquids (ILs) are promising nonvolatile electrolytes with high ionic conductivity. The large cations of ILs are, however, difficult to diffuse into solid electrodes, making them unappealing for application in some electrochemical devices. To address this issue, a new strategy is used to introduce proton conduction into an IL-based electrolyte. Poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) copolymer is functionalized with sulfonic acid through covalent attachment of taurine. The sulfonic acid-grafted P(VDF-HFP) electrospun mats consist of interconnected nanofibers, leading to remarkable improvement in dimensional stability of the mats. IL-based polymer electrolytes are prepared by immersing the modified mats in 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM(+)BF4(-)). It is found that the SO3(-) groups can have Lewis acid-base interactions with the cations (BMIM(+)) of IL to promote the dissociation of ILs, and provide additional proton conduction, resulting in significantly improved ionic conductivity. Using this novel electrolyte, polyaniline-based electrochromic devices show higher transmittance contrast and faster switching behavior. Furthermore, the sulfonic acid-grafted P(VDF-HFP) electrospun mats can also be lithiated, giving additional lithium ion conduction for the IL-based electrolyte, with which Li/LiCoO2 batteries display enhanced C-rate performance.

  20. Ionic liquids for nano- and microstructures preparation. Part 2: Application in synthesis.

    PubMed

    Łuczak, Justyna; Paszkiewicz, Marta; Krukowska, Anna; Malankowska, Anna; Zaleska-Medynska, Adriana

    2016-01-01

    Ionic liquids (ILs) are widely applied to prepare metal nanoparticles and 3D semiconductor microparticles. Generally, they serve as a structuring agent or reaction medium (solvent), however it was also demonstrated that ILs can play a role of a co-solvent, metal precursor, reducing as well as surface modifying agent. The crucial role and possible types of interactions between ILs and growing particles have been presented in the Part 1 of this review paper. Part 2 of the paper gives a comprehensive overview of recent experimental studies dealing with application of ionic liquids for preparation of metal and semiconductor based nano- and microparticles. A wide spectrum of preparation routes using ionic liquids is presented, including precipitation, sol-gel technique, hydrothermal method, nanocasting and ray-mediated methods (microwave, ultrasound, UV-radiation and γ-radiation). It was found that ionic liquids formed of a 1-butyl-3-methylimidazolium [BMIM] combined with tetrafluoroborate [BF4], hexafluorophosphate [PF6], and bis(trifluoromethanesulfonyl)imide [Tf2N] are the most often used ILs in the synthesis of nano- and microparticles, due to their low melting temperature, low viscosity and good transportation properties. Nevertheless, examples of other IL classes with intrinsic nanoparticles stabilizing abilities such as phosphonium and ammonium derivatives are also presented. Experimental data revealed that structure of ILs (both anion and cation type) affects the size and shape of formed metal particles, and in some cases may even determine possibility of particles formation. The nature of the metal precursor determines its affinity to polar or nonpolar domains of ionic liquid, and therefore, the size of the nanoparticles depends on the size of these regions. Ability of ionic liquids to form varied extended interactions with particle precursor as well as other compounds presented in the reaction media (water, organic solvents etc.) provides nano- and

  1. A derivative photoelectrochemical sensing platform for herbicide acetochlor based on TiO₂-poly (3-hexylthiophene)-ionic liquid nanocomposite film modified electrodes.

    PubMed

    Jin, Dangqin; Xu, Qin; Wang, Yanjuan; Hu, Xiaoya

    2014-09-01

    Nonelectroactive acetochlor can be indirectly determined through the photocatalytical degradation of acetochlor. A derivative visible light photoelectrochemical sensor for indirect detection of the herbicide acetochlor using TiO2-poly(3-hexylthiophene)-ionic liquid nanocomposite is constructed. Poly(3-hexylthiophene) (P3HT) was synthesized via chemical oxidative polymerization with anhydrous FeCl3 as oxidant, 3-hexylthiophene as monomer, chloroform as solvent, and the functional TiO2 nanoparticles were facilely prepared by blending TiO2 nanoparticles and P3HT at room temperature ionic liquid, 1-Butyl-3-methylimidazolium hexafluorophosphate solution. Operational parameters, including the photolysis time, ratios of TiO2 to P3HT, bias voltage and pH of buffer solution have been optimized. Under optimal conditions, the proposed photoelectrochemical method could detect acetochlor ranging from 0.5 to 20 μmol L(-1) with a detection limit of 0.2 nmol L(-1) at a signal-to-noise ratio of 3. The assay results of acetochlor in water samples with the proposed method were in acceptable agreement with those of the gas chromatograph-mass spectrometer (GC-MS) method. The promising sensor opens a new opportunity for fast, portable, and sensitive analysis of acetochlor in environmental samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Ionic liquid-mediated molecularly imprinted solid-phase extraction coupled with gas chromatography-electron capture detector for rapid screening of dicofol in vegetables.

    PubMed

    Yan, Hongyuan; Sun, Ning; Han, Yehong; Yang, Chen; Wang, Mingyu; Wu, Ruijun

    2013-09-13

    New ionic liquid-mediated molecularly imprinted polymers (IL-MIPs) were prepared by precipitation polymerization using 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM(+)PF6(-)) as the auxiliary solvent, α-chloro-DDT as the dummy template, and they were successfully applied as the sorbents of solid-phase extraction (SPE) for rapid screening of dicofol from cabbage, tomato, and carrot samples. The IL-MIPs were characterized by FTIR, FE-SEM, static adsorption and chromatographic evaluation, and the results revealed that the IL-MIPs had higher adsorption capacity and selectivity to dicofol in aqueous solution than that of ionic liquid-mediated non-imprinted polymers (IL-NIPs) and non-imprinted polymers (NIPs). Under the optimized conditions, the IL-MIPs-SPE-GC method offered good linearity (0.4-40.0ngg(-1), r(2)=0.9995) and the average recoveries of dicofol at three spiked levels were in a range of 84.6-104.1% (n=3) with RSD≤7.6%. The proposed method obviously improved the selectivity and purification effect, and eliminated the effect of template leakage on dicofol quantitative analysis. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Ultra-trace determination of lead in water and food samples by using ionic liquid-based single drop microextraction-electrothermal atomic absorption spectrometry.

    PubMed

    Manzoori, Jamshid L; Amjadi, Mohammad; Abulhassani, Jafar

    2009-06-30

    An improved single drop microextraction procedure was developed for the preconcentration of lead prior to its determination by electrothermal atomic absorption spectrometry. Ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate [C4MIM][PF6], was used as an alternative to volatile organic solvents for extraction. Lead was complexed with ammonium pyrroldinedithiocarbamate (APDC) and extracted into a 7-microL ionic liquid drop. The extracted complex was directly injected into the graphite furnace. Several variables affecting microextraction efficiency and ETAAS signal, such as pyrolysis and atomization temperature, pH, APDC concentration, extraction time, drop volume and stirring rate were investigated and optimized. In the optimum experimental conditions, the limit of detection (3s) and the enhancement factor were 0.015 microg L(-1) and 76, respectively. The relative standard deviation (RSD) for five replicate determinations of 0.2 microg L(-1) Pb was 5.2%. The developed method was validated by the analysis of certified reference materials and applied successfully to the determination of lead in several real samples.

  4. Ionic liquid-based single drop microextraction combined with electrothermal atomic absorption spectrometry for the determination of manganese in water samples.

    PubMed

    Manzoori, Jamshid L; Amjadi, Mohammad; Abulhassani, Jafar

    2009-02-15

    Room temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate [C(4)MIM][PF(6)], was used as an alternative to volatile organic solvents in single drop microextraction-electrothermal atomic absorption spectrometry (SDME-ETAAS). Manganese was extracted from aqueous solution into a drop of the ionic liquid after complextaion with 1-(2-thiazolylazo)-2-naphthol (TAN) and the drop was directly injected into the graphite furnace. Several variables affecting microextraction efficiency and ETAAS signal, such as pyrolysis and atomization temperature, pH, TAN concentration, extraction time, drop volume and stirring rate were investigated and optimized. In the optimum experimental conditions, the limit of detection (3s) and the enhancement factor were 0.024 microg L(-1) and 30.3, respectively. The relative standard deviation (RSD) for five replicate determinations of 0.5 microg L(-1) Mn(II) was 5.5%. The developed method was validated by the analysis of a certified reference material (NIST SRM 1643e) and applied successfully to the determination of manganese in several natural water samples.

  5. Ionic Liquid as Reaction Medium for Synthesis of Hierarchically Structured One-Dimensional MoO2 for Efficient Hydrogen Evolution.

    PubMed

    Zhang, Baohua; Xue, Yiguo; Jiang, Anning; Xue, Zhimin; Li, Zhonghao; Hao, Jingcheng

    2017-03-01

    Hierarchically structured one-dimensional (1D) MoO2 is synthesized for the first time in ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([BMIM][Tf2N]). The synthesis system is very simple (single [BMIM][Tf2N] solvent plus MoO2(acac)2 reactant). [BMIM][Tf2N] itself works as both the reaction medium and the template for the formation of these interesting 1D MoO2 particles with ultrathin nanosheet subunits. The as-synthesized hierarchically 1D MoO2_40 particles exhibit remarkable electrocatalytic activity with good long-term cycle stability for the hydrogen evolution reaction (HER) in acidic media. The HER activity of present synthesized MoO2 is comparable to those of the most active Mo-based electrocatalysts in acid media reported up to now. Therefore, the ionic liquid route provides us with a newly powerful tool for the synthesis of interesting alternative to noble metal catalysts for efficient electrocatalytic production of hydrogen in acidic environment.

  6. Micro-electrodeposition in the presence of ionic liquid for the preconcentration of trace amounts of Fe, Co, Ni and Zn from aqueous samples

    NASA Astrophysics Data System (ADS)

    Zawisza, Beata; Sitko, Rafał

    2013-04-01

    The paper presents the preconcentration of trace elements via electrodeposition onto a (micro)aluminum cathode in the presence of ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6] as a supporting electrolyte. The advantages of the proposed method include very simple instrumentation for the preconcentration of trace elements and low-cost reagents. The experiment showed that the use of ionic liquid in the electrodeposition process significantly improves sensitivity, recovery and detection limits for the determination of trace amounts of iron, cobalt, nickel and zinc. The preconcentrated metals were determined using X-ray fluorescence spectrometry. The optimum parameters for electrodeposition such as pH, the volume of the analyzed solution, the voltage and the deposition time were studied. Under the optimized conditions, the detection limits were 5, 2, 3 and 6 μg L- 1 for iron, cobalt, nickel and zinc, respectively. The precision and recovery of the method were in the range of 3-5.5%, and 92-103%, respectively. The calibration was performed using aqueous standards of Fe(III), Co(II), Ni(II) and Zn(II) in the range 0.01-0.25 mg L- 1. The method was applied successfully in water analysis.

  7. Strontium nitrate extraction to ionic liquids by a crown ether: a molecular dynamics study of aqueous interfaces with C4mim+- vs C8mim+-based ionic liquids.

    PubMed

    Chaumont, A; Wipff, G

    2010-11-04

    In order to gain microscopic insights into the extraction mechanism of strontium cations by 18-crown-6 (18C6) to room temperature ionic liquids (ILs), we simulated by molecular dynamics (MD) strontium complexes in neat ionic liquids and at their interfaces with water. We compared two ILs, based on the PF(6)(-) anion and either 1-butyl-3-methylimidazolium (C(4)mim(+)) or 1-octyl-3-methylimidazolium (C(8)mim(+)) cations. Regarding the complexes, two states were considered: charged [Sr⊂18C6](2+) vs neutral [Sr⊂18C6,(NO(3))(2)], where the nitrates are either fully dissociated or coordinated to Sr. In "dry" or "humid" [C(4)mim][PF(6)] and in "dry" [C(8)mim][PF(6)] IL, the neutral complex is found to be the most stable one. In the binary IL/water solutions, the charged complexes mostly partition to the aqueous phase, whereas the neutral [Sr⊂18C6,(NO(3))(2)] complexes are more concentrated in the interfacial domain. The aqueous solutions in contact with the ionic liquids contain C(4)mim(+), but almost no C(8)mim(+) ions, supporting a classical extraction mechanism to [C(8)mim][PF(6)] and an ion exchange mechanism to [C(4)mim][PF(6)]. Furthermore, remarkable events occurred during the dynamics, where complexes were extracted to the IL phases. When compared to the interfacial landscapes obtained with the same solutes at a classical organic liquid (chloroform)/water interface, those with ILs allow us to better understand specific features of liquid-liquid extraction to ILs.

  8. Impact of ionic liquid-modified multiwalled carbon nanotubes on the crystallization behavior of poly(vinylidene fluoride).

    PubMed

    Xing, Chenyang; Zhao, Liping; You, Jichun; Dong, Wenyong; Cao, Xiaojun; Li, Yongjin

    2012-07-19

    The impact of pristine multiwalled carbon nanotubes (MWCNTs), an ionic liquid (IL), 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6], and the ionic liquid-modified MWCNTs (IL-MWCNTs) on the crystallization behavior of melt-crystallized poly(vinylidene fluoride) (PVDF) has been investigated. Pristine MWCNTs accelerate crystallization of PVDF as an efficient nucleation agent, while the formed crystals are mainly nonpolar α crystal form with few polar β crystals. Incorporation of only ionic liquid results in depression of the PVDF melt crystallization rate due to the miscibility of IL with PVDF but leads to a higher content of polar crystals (β and γ forms) than MWCNTs. The ionic liquid and MWCNTs show significant synergetic effects on both the nucleation and the formation of polar crystals for PVDF by melt crystallization. Addition of IL-MWCNTs not only improves the MWCNTs dispersion in PVDF matrix but also increases the overall crystallization rate of PVDF drastically. More important, the melt-crystallized PVDF nanocomposites with IL-MWCNTs show 100% polar polymorphs but no α crystal forms. To the best of our knowledge, this is the first report on the achievements of full polar crystal form in the melt-crystallized PVDF without mechanical deformation or electric field. The IL to MWCNTs ratio and the IL-MWCNTs loading content effects on the crystallization behavior of PVDF in the nanocomposites were also studied. It is considered that the specific interactions between >CF2 with the planar cationic imidazolium ring wrapped on the MWCNTs surface lead to the full zigzag conformations of PVDF; thus, nucleation in polar crystals (β and γ forms) lattice is achieved and full polar crystals are obtained by subsequent crystal growth from the nuclei.

  9. Aggregation behavior of Triton X-100 with a mixture of two room-temperature ionic liquids: can we identify the mutual penetration of ionic liquids in ionic liquid containing micellar aggregates?

    PubMed

    Rao, Vishal Govind; Mandal, Sarthak; Ghosh, Surajit; Banerjee, Chiranjib; Sarkar, Nilmoni

    2012-11-29

    In this manuscript, we have characterized two different micellar aggregates containing all nonvolatile components. We have shown (i) the effect of ethylammonium nitrate (EAN) addition on the properties of micellar solution of Triton X-100 in 1-butyl-3-methylimidazolium hexafluorophosphate (bmimPF(6)) and (ii) the effect of bmimPF(6) addition on the properties of micellar solution of Triton X-100 in EAN. To investigate the effect, we have used (1)H NMR, pulsed-field gradient spin-echo NMR (PFGSE NMR), and methyl orange (MO) and coumarin 153 (C-153) as absorption and emission probes, respectively. The penetration of added EAN inside the Triton X-100/bmimPF(6) micellar aggregates is indicated by (i) red shift in both the absorption spectra of MO and emission spectra of C-153 and (ii) downfield shift of proton signals of ethylene oxide units in Triton X-100. On the other hand, (1)H NMR and PFGSE NMR indicates the penetration of added bmimPF(6) inside the Triton X-100/EAN micellar aggregates. However, the constancy of both the absorption spectra of MO and emission spectra of C-153 indicates that the microenvironment around the probe molecules remains unaffected. We have also investigated the effect of micelle formation and the effect of penetration of ionic liquids (ILs) in micellar aggregates, on the solvation dynamics of C-153. The solvent relaxation around C-153 gets retarded on going from neat ILs to the micellar solution of Triton X-100 in ILs. In addition to this, we have also observed that with the addition of EAN in Triton X-100/bmimPF(6) micellar aggregates the solvation dynamics becomes faster, whereas with the addition of bmimPF(6) in Triton X-100/EAN micellar aggregates we did not observe any notable change in solvation dynamics. This observation further supports the conclusions drawn from UV-visible and NMR studies.

  10. Trace mercury determination in drinking and natural water samples by room temperature ionic liquid based-preconcentration and flow injection-cold vapor atomic absorption spectrometry.

    PubMed

    Martinis, Estefanía M; Bertón, Paula; Olsina, Roberto A; Altamirano, Jorgelina C; Wuilloud, Rodolfo G

    2009-08-15

    A liquid-liquid extraction procedure (L-L) based on room temperature ionic liquid (RTIL) was developed for the preconcentration and determination of mercury in different water samples. The analyte was quantitatively extracted with 1-butyl-3-methylimidazolium hexafluorophosphate ([C(4)mim][PF(6)]) under the form of Hg-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (Hg-5-Br-PADAP) complex. A volume of 500 microl of 9.0 mol L(-1) hydrochloric acid was used to back-extract the analyte from the RTIL phase into an aqueous media prior to its analysis by flow injection-cold vapor atomic absorption spectrometry (FI-CV-AAS). A preconcentration factor of 36 was achieved upon preconcentration of 20 mL of sample. The limit of detection (LOD) obtained under the optimal conditions was 2.3ngL(-1) and the relative standard deviation (RSD) for 10 replicates at 1 microg L(-1) Hg(2+) was 2.8%, calculated with peaks height. The method was successfully applied to the determination of mercury in river, sea, mineral and tap water samples and a certified reference material (CRM).

  11. Magnetic stirrer induced dispersive ionic-liquid microextraction for the determination of vanadium in water and food samples prior to graphite furnace atomic absorption spectrometry.

    PubMed

    Naeemullah; Kazi, Tasneem Gul; Tuzen, Mustafa

    2015-04-01

    A new dispersive liquid-liquid microextraction, magnetic stirrer induced dispersive ionic-liquid microextraction (MS-IL-DLLME) was developed to quantify the trace level of vanadium in real water and food samples by graphite furnace atomic absorption spectrometry (GFAAS). In this extraction method magnetic stirrer was applied to obtained a dispersive medium of 1-butyl-3-methylimidazolium hexafluorophosphate [C4MIM][PF6] in aqueous solution of (real water samples and digested food samples) to increase phase transfer ratio, which significantly enhance the recovery of vanadium - 4-(2-pyridylazo) resorcinol (PAR) chelate. Variables having vital role on desired microextraction methods were optimised to obtain the maximum recovery of study analyte. Under the optimised experimental variables, enhancement factor (EF) and limit of detection (LOD) were achieved to be 125 and 18 ng L(-1), respectively. Validity and accuracy of the desired method was checked by analysis of certified reference materials (SLRS-4 Riverine water and NIST SRM 1515 Apple leaves). The relative standard deviation (RSD) for 10 replicate determinations at 0.5 μg L(-1) of vanadium level was found to be <5.0%. This method was successfully applied to real water and acid digested food samples.

  12. Studies on the micropolarities of bmimBF4/TX-100/toluene ionic liquid microemulsions and their behaviors characterized by UV-visible spectroscopy.

    PubMed

    Li, Na; Gao, Yan'an; Zheng, Liqiang; Zhang, Jin; Yu, Li; Li, Xinwei

    2007-01-30

    Ionic liquids (ILs), 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF4), were substituted for polar water and formed nonaqueous microemulsions with toluene by the aid of nonionic surfactant TX-100. The phase behavior of the ternary system was investigated, and microregions of bmimBF4-in-toluene (IL/O), bicontinuous, and toluene-in-bmimBF4 (O/IL) were identified by traditional electrical conductivity measurements. Dynamic light scattering (DLS) revealed the formation of the IL microemulsions. The micropolarities of the IL/O microemulsions were investigated by the UV-vis spectroscopy using the methyl orange (MO) and methylene blue (MB) as absorption probes. The results indicated that the polarity of the IL/O microemulsion increased only before the IL pools were formed, whereas a relatively fixed polar microenvironment was obtained in the IL pools of the microemulsions. Moreover, UV-vis spectroscopy has also shown that ionic salt compounds such as Ni(NO3)2, CoCl2, CuCl2, and biochemical reagent riboflavin could be solubilized into the IL/O microemulsion droplets, indicating that the IL/O microemulsions have potential application in the production of metallic or semiconductor nanomaterials, and in biological extractions or as solvents for enzymatic reactions. The IL/O microemulsions may have some expected effects due to the unique features of ILs and microemulsions.

  13. A novel ionic liquid/micro-volume back extraction procedure combined with flame atomic absorption spectrometry for determination of trace nickel in samples of nutritional interest.

    PubMed

    Dadfarnia, Shayesteh; Shabani, Ali Mohammad Haji; Bidabadi, Mahboubeh Shirani; Jafari, Abbas Ali

    2010-01-15

    A simple, highly sensitive and environment-friendly method for the determination of trace amount of nickel ion in different matrices is proposed. In the preconcentration step, the nickel from 10 mL of an aqueous solution was extracted into 500 microL of ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate [C(4)MIM][PF(6)], containing PAN as complexing agent. Subsequently, the PAN complex was back-extracted into 250 microL of nitric acid solution, and 100 microL of it was analyzed by flow injection flame atomic absorption spectrometry (FI-FAAS). The main parameter influencing the extraction and determination of nickel, such as pH, concentration of PAN, extraction time and temperature, ionic strength, and concentration of stripping acid solution, were optimized. An enhancement factor of 40.2 was achieved with 25 mL sample. The limit of detection (LOD) and quantification obtained under the optimum conditions were 12.5 and 41.0 microg L(-1), respectively. To validate the proposed methods two certified reference materials 681-I and BCR No. 288 were analyzed and the results were in good agreement with the certified values. The proposed method was successfully applied to determination of nickel in water samples, rice flour and black tea.

  14. Molecular dynamics simulation of the structure and interfacial free energy barriers of mixtures of ionic liquids and divalent salts near a graphene wall.

    PubMed

    Gómez-González, Víctor; Docampo-Álvarez, Borja; Méndez-Morales, Trinidad; Cabeza, Oscar; Ivaništšev, Vladislav B; Fedorov, Maxim V; Gallego, Luis J; Varela, Luis M

    2016-12-21

    A molecular dynamics study of mixtures of 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF4]) with magnesium tetrafluoroborate (Mg[BF4]2) confined between two parallel graphene walls is reported. The structure of the system is analyzed by means of ionic density profiles, lateral structure of the first layer close to the graphene surface and angular orientations of imidazolium cations. Free energy profiles for divalent magnesium cations are calculated using two different methods in order to evaluate the height of the potential barriers near the walls, and the results are compared with those of mixtures of the same ionic liquid and a lithium salt (Li[BF4]). Preferential adsorption of magnesium cations is analyzed using a simple model and compared to that of lithium cations, and vibrational densities of states are calculated for the cations close to the walls analyzing the influence of the graphene surface charge. Our results indicate that magnesium cations next to the graphene wall have a roughly similar environment to that in the bulk. Moreover, they face higher potential barriers and are less adsorbed on the charged graphene walls than lithium cations. In other words, magnesium cations have a more stable solvation shell than lithium ones.

  15. Development and optimization of a naphthoic acid-based ionic liquid as a "non-organic solvent microextraction" for the determination of tetracycline antibiotics in milk and chicken eggs.

    PubMed

    Gao, Jiajia; Wang, Hui; Qu, Jingang; Wang, Huili; Wang, Xuedong

    2017-01-15

    In traditional ionic liquids (ILs)-based microextraction, ILs are often used as extraction and dispersive solvents; however, their functional effects are not fully utilized. Herein, we developed a novel ionic liquid 1-butyl-3-methylimidazolium naphthoic acid salt ([C4MIM][NPA]) with strong acidity. It was used as a mixed dispersive solvent with conventional [C2MIM][BF4] in "functionalized ionic liquid-based non-organic solvent microextraction (FIL-NOSM)" for determination of tetracycline antibiotics (TCs) in milk and eggs. Utilization of [C4MIM][NPA] in FIL-NOSM method increased extraction recoveries (ERs) of TCs by more than 20% and eliminated the pH adjustment step because of its strong acidity. Under optimized conditions based on central composite design, the ERs of four TCs were 94.1-102.1%, and the limitsofdetection were 0.08-1.12μgkg(-1) in milk and egg samples. This proposed method provides high extraction efficiency, less pretreatment time and requires non-organic solvents for determination of trace TC concentrations in complex animal-based food matrices.

  16. Low-temperature heat capacities of 1-alkyl-3-methylimidazolium bis(oxalato)borate ionic liquids and the influence of anion structural characteristics on thermodynamic properties.

    PubMed

    Yang, Miao; Zhao, Jun-Ning; Liu, Qing-Shan; Sun, Li-Xian; Yan, Pei-Fang; Tan, Zhi-Cheng; Welz-Biermann, Urs

    2011-01-07

    Two chelated orthoborate ionic liquids (ILs), 1-butyl-3-methylimidazolium bis(oxalato)borate ([Bmim][BOB]) and 1-hexyl-3-methylimidazolium bis(oxalato)borate ([Hmim][BOB]), were prepared and characterized. Their thermodynamic properties were studied using adiabatic calorimetry and differential scanning calorimetry (DSC). The thermodynamic properties of the two ILs were evaluated and compared with each other, and then with those of other [Bmim] type ILs. The results clearly indicate that for a given cation (or anion) and at a certain temperature, the more atoms in the anion (or cation), the higher the heat capacity; the higher glass-transition temperatures of [BOB] type ILs than others are mainly caused by the higher symmetry of the orthoborate anion structure. It is suggested that a high content of strong electronegative atoms and C(n) or C(nv) (n = 1,2,3,…,∞) point group symmetry in the anion are favorable for the design and synthesis of room temperature ILs with a wide liquid range.

  17. Comparing an ionic liquid to a molecular solvent in the cesium cation extraction by a calixarene: a molecular dynamics study of the aqueous interfaces.

    PubMed

    Sieffert, Nicolas; Wipff, Georges

    2006-10-05

    We report a molecular dynamics (MD) study of the interfacial behavior of key partners involved in the Cs(+) cation extraction by a calix[4]arene-crown-6 host (L), comparing an ionic liquid (IL) to a classical molecular solvent (chloroform) as receiving "oil" phase. The IL is composed of hydrophobic 1-butyl-3-methylimidazolium cations (BMI(+)) and bis(trifluoromethylsulfonyl)imide anions (Tf(2)N(-)) and forms a biphasic system with water. The simulations reveal similarities but also interesting differences between the two types of interfaces. Much longer times are needed to "equilibrate" IL systems, compared to classical liquid mixtures, and there is more intersolvent mixing with the IL than with chloroform, especially concerning the water-in-oil content. There is also some excess of the BMI(+) cations over the Tf(2)N(-) anions in the aqueous phase. Simulations on the Na(+)NO(3)(-) and Cs(+)NO(3)(-) ions show that they sometimes interact at the interface with the IL ions, forming hydrated intimate ion pairs, whereas they are "repelled" by the classical interface. The LCs(+) complex and L ligand also behave differently, depending on the "oil phase". They are better solvated by the IL than by chloroform and thus poorly attracted at the IL interface, whereas they adsorb at the chloroform interface, adopting well-defined amphiphilic orientations. The results are discussed in the context of assisted ion transfer and provide a number of arguments explaining the specificity and efficiency of IL based, compared to classical extraction systems.

  18. DFT Study of the Reaction Mechanisms of Carbon Dioxide and its Isoelectronic Molecules CS2 and OCS Dissolved in Pyrrolidinium and Imidazolium Acetate Ionic Liquids.

    PubMed

    Danten, Y; Cabaço, M I; Coutinho, J A P; Pinaud, Noël; Besnard, M

    2016-06-16

    The reaction mechanisms of CO2 and its isoelectronic molecules OCS and CS2 dissolved in N-butyl-N-methylpyrrolidinium acetate and in 1-butyl-3-methylimidazolium acetate were investigated by DFT calculations in "gas phase". The analysis of predicted multistep pathways allowed calculating energies of reaction and energy barriers of the processes. The major role played by the acetate anion in the degradation of the solutes CS2 and OCS as well as in the capture of OCS and CO2 by the imidazolium ring is highlighted. In both ionic liquids, this anion governs the conversion of CS2 into OCS and of OCS into CO2 through interatomic S-O exchanges between the anion and the solutes with formation of thioacetate anions. In imidazolium acetate, the selective capture of CS2 and OCS by the imidazolium ring competes with the S-O exchanges. From the calculated values of the energy barriers a basicity scale of the anions is proposed. The (13)C NMR chemical shifts of the predicted adducts were calculated and agree well with the experimental observations. It is argued that the scenario issued from the calculated pathways is shown qualitatively to be independent from the functionals and basis set used, constitute a valuable tool in the understanding of chemical reactions taking place in liquid phase.

  19. Measurement of Ultraslow Rotational Dynamics of Probes in Imidazolium-Based Ionic Liquids Near and Below the Glass Transition Temperature: Studying the Role of Structural Heterogeneity on Dynamic Heterogeneity

    NASA Astrophysics Data System (ADS)

    Mendoza, Kayla; Udugama-Arachchilage, Rakhitha; Bardak, Fehmi; Tamas, George; Quitevis, Edward

    2014-03-01

    The dynamics of imidazolium-based ionic liquids were probed in the supercooled liquid regime by observing the fluorescence recovery after photobleaching of directionally oriented tetracene molecules. Spatial heterogeneity arises in ionic liquids containing a 1-alkyl-3-methylimidazolium cation for alkyl chain lengths equal to and exceeding four carbons; aggregation of the alkyl tails leads to the formation of non-polar domains, which increase in size with increasing alkyl chain length. Near the glass transition, supercooled liquids relax non-exponentially, and this non-exponentiality has been attributed to dynamic heterogeneity. The purpose of this study was to observe the role of structural heterogeneity on dynamic heterogeneity. The rotational dynamics of tetracene in 1-butyl-3-methylimidazolium bistriflate, 1, 3-dibutylimidazolium bistriflate, and 1-heptyl-3-methylimidazlium bistriflate were observed in the vicinity of their glass transition temperatures. From the weak dependence of the degree of non-exponentiality exhibited by the relaxation function on alky chain length and cation symmetry, it was concluded that structural heterogeneity does not play a strong role in determining dynamic heterogeneity. This work was supported by NSF grant CHE-1153077.

  20. Temperature-controlled ionic liquid-based ultrasound-assisted microextraction for preconcentration of trace quantity of cadmium and nickel by using organic ligand in artificial saliva extract of smokeless tobacco products

    NASA Astrophysics Data System (ADS)

    Arain, Sadaf Sadia; Kazi, Tasneem Gul; Arain, Asma Jabeen; Afridi, Hassan Imran; Baig, Jameel Ahmed; Brahman, Kapil Dev; Naeemullah; Arain, Salma Aslam

    2015-03-01

    A new approach was developed for the preconcentration of cadmium (Cd) and nickel (Ni) in artificial saliva extract of dry snuff (brown and black) products using temperature-controlled ionic liquid-based ultrasound-assisted dispersive liquid-liquid microextraction (TIL-UDLLμE) followed by electrothermal atomic absorption spectrometry (ETAAS). The Cd and Ni were complexed with ammonium pyrrolidinedithiocarbamate (APDC), extracted in ionic liquid drops, 1-butyl-3-methylimidazolium hexafluorophosphate [C4MIM][PF6]. The multivariate strategy was applied to estimate the optimum values of experimental variables influence the % recovery of analytes by TIL-UDLLμE method. At optimum experimental conditions, the limit of detection (3s) were 0.05 and 0.14 μg L-1 while relative standard deviations (% RSD) were 3.97 and 3.55 for Cd and Ni respectively. After extraction, the enhancement factors (EF) were 87 and 79 for Cd and Ni, respectively. The RSD for six replicates of 10 μg L-1 Cd and Ni were 3.97% and 3.55% respectively. To validate the proposed method, certified reference material (CRM) of Virginia tobacco leaves was analyzed, and the determined values of Cd and Ni were in good agreement with the certified values. The concentration of Cd and Ni in artificial saliva extracts corresponds to 39-52% and 21-32%, respectively, of the total contents of both elements in dry brown and black snuff products.

  1. Temperature-controlled ionic liquid-based ultrasound-assisted microextraction for preconcentration of trace quantity of cadmium and nickel by using organic ligand in artificial saliva extract of smokeless tobacco products.

    PubMed

    Arain, Sadaf Sadia; Kazi, Tasneem Gul; Arain, Asma Jabeen; Afridi, Hassan Imran; Baig, Jameel Ahmed; Brahman, Kapil Dev; Naeemullah; Arain, Salma Aslam

    2015-03-05

    A new approach was developed for the preconcentration of cadmium (Cd) and nickel (Ni) in artificial saliva extract of dry snuff (brown and black) products using temperature-controlled ionic liquid-based ultrasound-assisted dispersive liquid-liquid microextraction (TIL-UDLLμE) followed by electrothermal atomic absorption spectrometry (ETAAS). The Cd and Ni were complexed with ammonium pyrrolidinedithiocarbamate (APDC), extracted in ionic liquid drops, 1-butyl-3-methylimidazolium hexafluorophosphate [C4MIM][PF6]. The multivariate strategy was applied to estimate the optimum values of experimental variables influence the % recovery of analytes by TIL-UDLLμE method. At optimum experimental conditions, the limit of detection (3s) were 0.05 and 0.14μgL(-1) while relative standard deviations (% RSD) were 3.97 and 3.55 for Cd and Ni respectively. After extraction, the enhancement factors (EF) were 87 and 79 for Cd and Ni, respectively. The RSD for six replicates of 10μgL(-1) Cd and Ni were 3.97% and 3.55% respectively. To validate the proposed method, certified reference material (CRM) of Virginia tobacco leaves was analyzed, and the determined values of Cd and Ni were in good agreement with the certified values. The concentration of Cd and Ni in artificial saliva extracts corresponds to 39-52% and 21-32%, respectively, of the total contents of both elements in dry brown and black snuff products.

  2. Ionic liquids as a key medium for efficient extraction of copper complexes from chia seeds (Salvia hispanica L.).

    PubMed

    Wojcieszek, Justyna; Popowski, Dominik; Ruzik, Lena

    2016-05-15

    Due to insufficient information, the aim of study was to concern on the optimization of extraction procedure of selected metal complexes with flavonoids from chia seeds. Evaluation of the amount of elements in compound, not only their total concentration content, is highly important due to the fact, that only a part from total content of metal is absorbed by human body. At the beginning the total amount of elements in chia seeds was established as 14.51±0.42 µg g(-1) for copper, 57.44±1.23 µg g(-1) for manganese, 81.12±1.89 µg g(-1) for zinc and 0.35±0.13 µg g(-1) for cobalt. After the most suitable solvent was established, effects of several parameters on the efficiency of metal extraction were studied. Solvent concentration, solid-solvent ratio, extraction method, extraction time and temperature have been investigated as independent variables. The optimal extraction conditions included vortexing during 20 min in 50°C, using an ionic liquid (1-butyl-3-methylimidazolium bromide) as an extractant, with solid-solvent ratio of 1:20. The determination of total and extractable amount of metals in chia seeds was carried out by standalone ICP MS. In addition, a complementary analysis of extracted metal complexes was performed using SEC-ICP MS method. It was confirmed that the ionic liquid is able to extract different copper complexes in comparison with commonly used solvents. The study indicated that extraction by using an ionic liquid has been successfully applied for determination of metals and metal complexes in chia seeds. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Vortex-assisted ionic liquid-based dispersive liquid-liquid microextraction for assessment of chromium species in artificial saliva extract of different chewing tobacco products.

    PubMed

    Akhtar, Asma; Kazi, Tasneem Gul; Afridi, Hassan Imran; Musharraf, Syed Ghulam; Talpur, Farah Naz; Khan, Noman; Bilal, Muhammad; Khan, Mustafa

    2016-12-01

    A novel dispersive liquid-liquid microextraction (ILDLLμE) method using an extracting solvent (ionic liquid) and dispersant (Triton X-114) was developed for the separation and preconcentration of hexavalent chromium (Cr(6+)) in artificial saliva extract (ASE) of chewing tobacco products, gutkha, and mainpuri (n = 23). In the proposed method, the extraction of Cr(6+) was accomplished by using ammonium pyrrolidinedithiocarbamate (APDC) as complexing agent and 1-butyl-3-methylimidazolium hexafluorophosphate [C4MIM] [PF6] as extracting solvent. The tiny droplet of metal chelate was then dispersed into TX-114 emulsion, using vortex mixer. Various parameters such as concentration of APDC, pH of the solution, volume of [C4MIM] [PF6], and TX-114 as well as extraction time were studied. Under the most favorable conditions, the limit of detection was found to be 0.068 μg/L with the relative standard deviation <5 %. The enrichment factor of developed method was found as 62.5, and method has been effectively applied for the analysis of Cr species in artificial saliva extract of gutkha and mainpuri products. The Cr(6+) was quantitatively recovered (<97 %) under optimal conditions, while the recovery of trivalent specie (Cr(3+)), at the same experimental conditions, was observed to be <5 %. The Cr(3+) was determined by the difference of total Cr and Cr(6+) in artificial saliva extract of selected STP. Health risks associated with the intake of total Cr in gutkha and mainpuri were assessed in terms of estimated daily intake, such as carcinogenic and noncarcinogenic risks. Estimated daily intake of Cr via chewing 10 g/day of gutkha and mainpuri was found to be below the maximum tolerable daily intake, whereas the calculated risk of cancer for Cr was observed in the acceptable range of 10E(-6)-10E(-4), except some brands of gutkha. Graphical Abstract ᅟ.

  4. The Overriding Roles of Concentration and Hydrophobic Effect on Structure and Stability of Heme Protein Induced by Imidazolium-Based Ionic Liquids.

    PubMed

    Jha, Indrani; Kumar, Awanish; Venkatesu, Pannuru

    2015-07-02

    Spectroscopic and molecular docking investigations were carried out to characterize the effect of imidazolium-based ionic liquids (ILs) with varying chain length of the cation on the thermal stability as well as spectroscopic behavior of heme protein hemoglobin (Hb). The goal of this work is to investigate the role of concentration of ILs, the effect of alkyl chain length of the cation, and the related Hofmeister series on the structure of Hb. To achieve this goal, a series of ILs possessing same Cl(-) anion and a set of cation [Cnmim](+) with increasing chain length such as 1-ethyl-3-methylimidazolium chloride ([Emim][Cl]), 1-butyl-3-methylimidazolium chloride ([Bmim][Cl]), 1-hexyl-3-methylimidazolium chloride ([Hmim][Cl]), and 1-decyl-3-methylimidazolium chloride ([Dmim][Cl]) were used in this study. It was observed that the stability of the protein was concentration dependent as well as the hydrophobic interactions between [Cnmim](+) of ILs, and the amino acid residues in the protein played a major role in protein unfolding. As a consequence, the destabilization tendency of the ILs toward the Hb increases with increasing chain length of the cation of ILs. Additionally, the cations of the ILs obeyed the Hofmeister series when arranged in the order of providing stability to Hb structure.

  5. Toxicity of two imidazolium ionic liquids, [bmim][BF4] and [omim][BF4], to standard aquatic test organisms: Role of acetone in the induced toxicity.

    PubMed

    Tsarpali, Vasiliki; Dailianis, Stefanos

    2015-07-01

    The main goal of this study was to investigate the toxicity of the imidazolium-based ionic liquids (ILs), [bmim][BF4] (1-butyl-3-methylimidazolium tetrafluoroborate) and [omim][BF4] (1-octyl-3-methylimidazolium tetrafluoroborate), in battery of standard aquatic toxicity test organisms. Specifically, exposure of the algae Scenedesmus rubescens, crustaceans Thamnocephalus platyurus and Artemia franciscana, rotifers Brachionus calyciflorus and Brachionus plicatilis and bivalve Mytilus galloprovincialis to different concentrations of [bmim][BF4], [omim][BF4] and/or a binary mixture of [bmim][BF4]-[omim][BF4] (1:1) with or without acetone (carrier solvent), revealed that solvent can differentially mediate ILs' toxic profile. Acetone's ability to differentially affect ILs' cation's alkyl chain length, as well as the hydrolysis of [BF4(-)] anions was evident. Given that the toxic potency of the tested ILs seemed to be equal or even higher (in some cases) than those of conventional organic solvents, the present study revealed that the characterization of imidazolium-based ILs as "green solvents" should not be generalized, at least in case of their natural occurrence in mixtures with organic solvents, such as acetone. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. X-ray Reflectivity Study of the Interaction of an Imidazolium-Based Ionic Liquid with a Soft Supported Lipid Membrane.

    PubMed

    Bhattacharya, G; Giri, R P; Saxena, H; Agrawal, V V; Gupta, A; Mukhopadhyay, M K; Ghosh, S K

    2017-02-07

    Ionic liquids (ILs) are important for their antimicrobial activity and are found to be toxic to some microorganisms. To shed light on the mechanism of their activities, the interaction of an imidazolium-based IL 1-butyl-3-methylimidazolium tetrfluoroborate ([BMIM][BF4]) with E. coli bacteria and cell-membrane-mimicking lipid mono- and bilayers has been studied. The survival of the bacteria and corresponding growth inhibition are observed to be functions of the concentration of the IL. The IL alters the pressure-area isotherm of the monolayer formed at an air-water interface by the 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid. The in-plane elasticity of the lipid layer is reduced as a consequence of the insertion of this IL. The X-ray reflectivity study from a polymer-supported lipid bilayer shows strong perturbation in the self-assembled structure of the bilayer due to the interaction. As a consequence, there is a considerable decrease in bilayer thickness and a corresponding increase in electron density. These results, however, depend on the chain configurations of the lipid molecules.

  7. Theinfluence of a hierarchical porous carbon network on the coherent dynamics of a nanoconfined room temperature ionic liquid: A neutron spin echo and atomistic simulation investigation

    SciTech Connect

    Banuelos, Jose Leo; Feng, Guang; Fulvio, Pasquale F; Li, Song; Rother, Gernot; Arend, Nikolas; Faraone, Antonio; Dai, Sheng; Cummings, Peter T; Wesolowski, David J

    2014-01-01

    The molecular-scale dynamic properties of the room temperature ionic liquid (RTIL) 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, or [C4mim+ ][Tf2N ], confined in hierarchical microporous mesoporous carbon, were investigated using neutron spin echo (NSE) and molecular dynamics (MD) simulations. Both NSE and MD reveal pronounced slowing of the overall collective dynamics, including the presence of an immobilized fraction of RTIL at the pore wall, on the time scales of these approaches. A fraction of the dynamics, corresponding to RTIL inside 0.75 nm micropores located along the mesopore surfaces, are faster than those of RTIL in direct contact with the walls of 5.8 nm and 7.8 nm cylindrical mesopores. This behavior is ascribed to the near-surface confined-ion density fluctuations resulting from the ion ion and ion wall interactions between the micropores and mesopores as well as their confinement geometries. Strong micropore RTIL interactions result in less-coordinated RTIL within the micropores than in the bulk fluid. Increasing temperature from 296 K to 353 K reduces the immobilized RTIL fraction and results in nearly an order of magnitude increase in the RTIL dynamics. The observed interfacial phenomena underscore the importance of tailoring the surface properties of porous carbons to achieve desirable electrolyte dynamic behavior, since this impacts the performance in applications such as electrical energy storage devices.

  8. Probing electron density of H-bonding between cation-anion of imidazolium-based ionic liquids with different anions by vibrational spectroscopy.

    PubMed

    Gao, Yan; Zhang, Liqun; Wang, Yong; Li, Haoran

    2010-03-04

    Attenuated total reflection infrared spectroscopy and density functional theory calculation have been employed to study the spectral properties of imidazolium-based ionic liquids (ILs) with different anions. ILs based on 1-butyl-3-methylimidazolium cation with different anions, OH(-), CF(3)CO(2)(-), HSO(4)(-), H(2)PO(4)(-), Cl(-), PF(6)(-), and BF(4)(-), are investigated in the present work. It has been shown that the C(2)-H stretching vibration of the imidazolium ring is closely related to the electron density of H-bonding between the two closest cations and anions for pure ILs. The electron density of H-bonding between cation and anion with different anions decreases in the order [OH](-) > [H(2)PO(4)](-) > [HSO(4)](-) > [CF(3)CO(2)](-) > [Cl](-) > [BF(4)](-) > [PF(6)](-). For aqueous ILs, with increasing water content, the aromatic C-H stretching vibration of the imidazolium cation showed systematic blue-shifts. Especially for BmimOH, the nu(C(2))(-H) undergoes a drastic blue-shift by 58 cm(-1), suggesting that the formation of the strong hydrogen bonds O-H...O may greatly weaken the electron density of H-bonding between the cation and anion of ILs.

  9. [Separation and determination of optical isomers of phenylephrine by chiral ligand exchange capillary elcctrophoresis coupling with the promoting effect of ionic liquid].

    PubMed

    Yang, Simei; Zhang, Jiayao; Li, Fei; Hu, Xufang; Cao, Qiue

    2016-01-01

    A method for the separation and determination of optical isomers of phenylephrine was developed based on the promoting effect of non-chiral ionic liquid on chiral ligand-exchange capillary electrophoresis after the electrophoretic parameters were optimized systematically. R-phenylephrine and S-phenylephrine can be separated and determined effectively in 20 mmol/L Tris-H3PO4 buffer solution (pH 5.4) composed of 4.0 mmol/L Cu(II), 8.0 mmol/L L-proline (L-Pro) and 15 mmol/L 1-butyl-3-methylimidazolium chloride ([BMIM] Cl) with the applied voltage of 20 kV, capillary temperature of 25 °C , detection wavelength of 254 nm, and injection of 5 s at 3,447 Pa. The resolution of R- and S-phenylephrines was 1. 42. The linear ranges for the determination of R-phenylephrine and S-phenylephrine were 12. 5 - 150 mg/L and 15. 0-150 mg/L, respectively. The method has been satisfactorily used for the determination of R-phenylephrine and S-phenylephrine in the spiked blood and urine samples. The spiked recoveries in the urine sample were in the range of 93. 7% -108. 2% with the RSDs lower than 3. 18% (n= 3) , and the spiked recoveries in the blood sample were in the range of 91. 4% and 113. 1% with the RSDs lower than 4. 82% (n =3).

  10. Facile fabrication of a novel anisotropic gold nanoparticle-chitosan-ionic liquid/graphene modified electrode for the determination of theophylline and caffeine.

    PubMed

    Yang, Guangming; Zhao, Faqiong; Zeng, Baizhao

    2014-09-01

    In the present study, a suspension solution containing anisotropic gold nanoparticle (GNP), chitosan (CHIT) and ionic liquid (IL, i.e. 1-butyl-3-methylimidazolium tetrafluoroborate, [BMIM][BF4]), is prepared by reducing HAuCl4 with sodium citrate in CHIT-IL aqueous solution. The hybrid solution is coated on a graphene (r-GO) modified glassy carbon electrode to construct an electrochemical sensor for the determination of theophylline (TP) and caffeine (CAF). The obtained hybrid film shows rough surface, and anisotropic GNPs are well dispersed on it. The factors concerning this assay strategy are carefully investigated, including the components of the hybrid film, the concentrations of r-GO, HAuCl4 and IL, and the pH of buffer solution. Under the optimized conditions, the linear response ranges are 2.50×10(-8)-2.10×10(-6) mol L(-1) and 2.50×10(-8)-2.49×10(-6) mol L(-1) for TP and CAF, respectively; the detection limits are 1.32×10(-9) mol L(-1) and 4.42×10(-9) mol L(-1), respectively. The electrochemical sensor shows good reproducibility, stability and selectivity, and it has been successfully applied to the determination of TP and CAF in real samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Two solid-phase recycling method for basic ionic liquid [C4mim]Ac by macroporous resin and ion exchange resin from Schisandra chinensis fruits extract.

    PubMed

    Ma, Chun-hui; Zu, Yuan-gang; Yang, Lei; Li, Jian

    2015-01-22

    In this study, two solid-phase recycling method for basic ionic liquid (IL) 1-butyl-3-methylimidazolium acetate ([C4mim]Ac) were studied through a digestion extraction system of extracting biphenyl cyclooctene lignans from Schisandra chinensis. The RP-HPLC detection method for [C4mim]Ac was established in order to investigate the recovery efficiency of IL. The recycling method of [C4mim]Ac is divided into two steps, the first step was the separation of lignans from the IL solution containing HPD 5000 macroporous resin, the recovery efficiency and purity of [C4mim]Ac achieved were 97.8% and 67.7%, respectively. This method cannot only separate the lignans from [C4mim]Ac solution, also improve the purity of lignans, the absorption rate of lignans in [C4mim]Ac solution was found to be higher (69.2%) than that in ethanol solution (57.7%). The second step was the purification of [C4mim]Ac by the SK1B strong acid ion exchange resin, an [C4mim]Ac recovery efficiency of 55.9% and the purity higher than 90% were achieved. Additionally, [C4mim]Ac as solvent extraction of lignans from S. chinensis was optimized, the hydrolysis temperature was 90°C and the hydrolysis time was 2h.

  12. Silver Nanoparticles in Comparison with Ionic Liquid and rGO as Gate Dopant for Paper-Pencil-Based Flexible Field-Effect Transistors

    NASA Astrophysics Data System (ADS)

    Mandal, Soumen; Arun, Ravi Kumar; Nagahanumaiah; Chanda, Nripen; Das, Surajit; Agarwal, Pankaj; Akhtar, Jamil; Mishra, Prabhash

    2015-01-01

    Nanoparticle-based flexible field-effect transistors (FETs) containing carbon nanotubes (CNTs) and silicon nanowires (SiNWs) have attracted tremendous attention, since their interesting device performance can be utilized for integrated nanoscale electronics. However, use of CNTs and SiNWs on polymer substrates poses serious limitations in terms of their fabrication procedure, repeatability, and biodegradability. In this article, we report for the first time the fabrication and characteristics of solution-processed FETs on a paper substrate doped with easily prepared silver nanoparticles (AgNPs). To compare the FET performance, we fabricated two other FETs on paper containing ionic liquid (IL, 1-butyl-3-methylimidazolium octyl sulfate) and reduced graphene oxide (rGO) as dopants. We observe that the AgNP-based dopant generated good FET characteristics in terms of linear transconductance variations and higher carrier concentration values, showing negligible changes after bending and aging. In comparison with the AgNP-FET, the rGO- and IL-based dopants yielded high carrier mobilities, but the rGO-based FET is more susceptible to aging and bending. The excellent linearity of the I DS- V G curve found for the AgNP-FET ensures its applicability for devices requiring linear transfer characteristics such as linear amplifiers.

  13. Dielectric relaxation dynamics and AC conductivity scaling of metal-organic framework (MOF-5) based polymer electrolyte nanocomposites incorporated with ionic liquid

    NASA Astrophysics Data System (ADS)

    Dutta, Rituraj; Kumar, A.

    2017-10-01

    Dielectric relaxation dynamics and AC conductivity scaling of a metal-organic framework (MOF-5) based poly (vinylidene fluoride-co-hexafluoropropylene) (PVdf-HFP) incorporated with 1-Butyl-3-methylimidazolium hexafluorophosphate have been studied over a frequency range of 40 Hz–5 MHz and in the temperature range of 300 K–380 K. High values of dielectric permittivity (~{{\\varepsilon }\\prime} ) having strong dispersion are obtained at low frequency because of interfacial polarization. The real part of the dielectric modulus spectra (M‧) shows no prominent peak, whereas the imaginary part (M″) shows certain peaks, with a reduction in relaxation time (τ) that can be attributed to a non-Debye relaxation mechanism. The spectra also depict both concentration- and temperature-independent scaling behavior. The power law dependent variation of AC conductivity follows the jump relaxation model and reveals activated ion hopping over diffusion barriers. The value of the frequency exponent is observed to decrease with increasing concentration of ionic liquid, indicating the forward hopping of ions in the relaxation process. The AC conductivity scaling curves at different temperatures also depict the temperature-independent relaxation dynamics.

  14. Photoinduced electron transfer between 2-methylanthraquinone and triethylamine in an ionic liquid: time-resolved EPR and transient absorption spectroscopy study.

    PubMed

    Zhu, Guanglai; Wang, Yu; Fu, Haiying; Xu, Xinsheng; Cui, Zhifeng; Ji, Xuehan; Wu, Guozhong

    2015-02-25

    Photoinduced electron transfer between 2-methylanthraquinone (MeAQ) and triethylamine (TEA) in a room-temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]), was investigated by comparing the time-resolved electron paramagnetic resonance (TR-EPR) spectroscopy and the transient absorption spectroscopy. The results of TR-EPR spectroscopy, in which MeAQ was 8 mmol L(-1) and TEA was 150 mmol L(-1), indicated that the transient radical would exist longer time in [bmim][PF6] than in acetonitrile. At the delay time of 8 μs after laser excitation, the TR-EPR signal transformed from an emissive peak into an absorptive peak when the experiment was performed in [bmim][PF6]. The results of the transient absorption spectroscopy, in which MeAQ was 0.1 mmol L(-1) and TEA was 2.2 mmol L(-1), showed that the efficiency and the rate of the photoinduced electron transfer reaction in [bmim][PF6] were obviously lower than that in acetonitrile. It was concluded that various factors, such as concentration, viscosity and local structural transformation of the solution, have an influence on the process of photoinduced electron transfer in [bmim][PF6]. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Inkjet printing of nanoporous gold electrode arrays on cellulose membranes for high-sensitive paper-like electrochemical oxygen sensors using ionic liquid electrolytes.

    PubMed

    Hu, Chengguo; Bai, Xiaoyun; Wang, Yingkai; Jin, Wei; Zhang, Xuan; Hu, Shengshui

    2012-04-17

    A simple approach to the mass production of nanoporous gold electrode arrays on cellulose membranes for electrochemical sensing of oxygen using ionic liquid (IL) electrolytes was established. The approach, combining the inkjet printing of gold nanoparticle (GNP) patterns with the self-catalytic growth of these patterns into conducting layers, can fabricate hundreds of self-designed gold arrays on cellulose membranes within several hours using an inexpensive inkjet printer. The resulting paper-based gold electrode arrays (PGEAs) had several unique properties as thin-film sensor platforms, including good conductivity, excellent flexibility, high integration, and low cost. The porous nature of PGEAs also allowed the addition of electrolytes from the back cellulose membrane side and controllably produced large three-phase electrolyte/electrode/gas interfaces at the front electrode side. A novel paper-based solid-state electrochemical oxygen (O(2)) sensor was therefore developed using an IL electrolyte, 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF(6)). The sensor looked like a piece of paper but possessed high sensitivity for O(2) in a linear range from 0.054 to 0.177 v/v %, along with a low detection limit of 0.0075% and a short response time of less than 10 s, foreseeing its promising applications in developing cost-effective and environment-friendly paper-based electrochemical gas sensors.

  16. Significantly improving enzymatic saccharification of high crystallinity index's corn stover by combining ionic liquid [Bmim]Cl-HCl-water media with dilute NaOH pretreatment.

    PubMed

    He, Yu-Cai; Liu, Feng; Gong, Lei; Zhu, Zheng-Zhong; Ding, Yun; Wang, Cheng; Xue, Yu-Feng; Rui, Huan; Tao, Zhi-Cheng; Zhang, Dan-Ping; Ma, Cui-Luan

    2015-01-01

    In this study, a pretreatment by combining acidified aqueous ionic liquid 1-butyl-3-methylimidazolium chloride (IL [Bmim]Cl) solution with dilute NaOH extraction was employed to pretreat high crystallinity index (CrI) of corn stover before its enzymatic saccharification. After NaOH extraction, [Bmim]Cl-HCl-water (78.8:1.2:20, w/w/w) media was used for further pretreatment at 130 °C for 30 min. After being enzymatically hydrolyzed for 48 h, corn stover pretreated could be biotransformed into reducing sugars in the yield of 95.1%. Furthermore, SEM, XRD and FTIR analyses of untreated and pretreated corn stovers were examined. It was found that the intact structure was disrupted by combination pretreatment and resulted in a porous and amorphous regenerated cellulosic material that greatly improved enzymatic hydrolysis. Finally, the recovered hydrolyzates obtained from the enzymatic hydrolysis of pretreated corn stovers could be fermented into ethanol efficiently. In conclusion, the combination pretreatment shows high potential application in future. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Solvation Structure of Imidazolium Cation in Mixtures of [C4mim][TFSA] Ionic Liquid and Diglyme by NMR Measurements and MD Simulations.

    PubMed

    Shimomura, Takuya; Kodama, Daisuke; Kanakubo, Mitsuhiro; Tsuzuki, Seiji

    2017-04-06

    Interactions of 1-butyl-3-methylimidazolium cation ([C4mim](+)) with bis(trifluoromethanesulfonyl)amide anion ([TFSA](-)) and diethyleneglycol dimethyl ether (diglyme) in mixtures of [C4mim][TFSA] ionic liquid and diglyme have been investigated using (1)H and (13)C NMR spectroscopy and molecular dynamics (MD) simulations. The results of NMR chemical shift measurements and MD simulations showed that the diglyme oxygen atoms have contact with the imidazolium hydrogen atoms of [C4mim](+) in the mixtures. The contact between the hydrogen atoms of imidazolium and the oxygen atoms of [TFSA](-) remains even when the diglyme mole fraction (xdiglyme) increases up to 0.9. However, the coordination numbers of the hydrogen atoms of [C4mim](+) with oxygen atoms of diglyme increase with xdiglyme. The [TFSA](-) anions around [C4mim](+) are not completely replaced by diglyme even at xdiglyme > 0.9. The MD simulations revealed that the diglymes also have contact with the butyl group of [C4mim](+). The methyl groups of diglyme prefer to have contact with the terminal methyl group of the butyl group, whereas the diglyme oxygen atoms prefer to have contact with the methylene group connected to the imidazolium ring of [C4mim](+).

  18. Photoinduced electron transfer between 2-methylanthraquinone and triethylamine in an ionic liquid: Time-resolved EPR and transient absorption spectroscopy study

    NASA Astrophysics Data System (ADS)

    Zhu, Guanglai; Wang, Yu; Fu, Haiying; Xu, Xinsheng; Cui, Zhifeng; Ji, Xuehan; Wu, Guozhong

    2015-02-01

    Photoinduced electron transfer between 2-methylanthraquinone (MeAQ) and triethylamine (TEA) in a room-temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]), was investigated by comparing the time-resolved electron paramagnetic resonance (TR-EPR) spectroscopy and the transient absorption spectroscopy. The results of TR-EPR spectroscopy, in which MeAQ was 8 mmol L-1 and TEA was 150 mmol L-1, indicated that the transient radical would exist longer time in [bmim][PF6] than in acetonitrile. At the delay time of 8 μs after laser excitation, the TR-EPR signal transformed from an emissive peak into an absorptive peak when the experiment was performed in [bmim][PF6]. The results of the transient absorption spectroscopy, in which MeAQ was 0.1 mmol L-1 and TEA was 2.2 mmol L-1, showed that the efficiency and the rate of the photoinduced electron transfer reaction in [bmim][PF6] were obviously lower than that in acetonitrile. It was concluded that various factors, such as concentration, viscosity and local structural transformation of the solution, have an influence on the process of photoinduced electron transfer in [bmim][PF6].