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Sample records for aqueous ionic melts

  1. Aqueous solutions of ionic liquids: microscopic assembly

    NARCIS (Netherlands)

    J.M. Vicent-Luna; D. Dubbeldam; P. Gómez-Álvarez; S. Calero

    2016-01-01

    Aqueous solutions of ionic liquids are of special interest, due to the distinctive properties of ionic liquids, in particular, their amphiphilic character. A better understanding of the structure-property relationships of such systems is hence desirable. One of the crucial molecular-level interactio

  2. Aqueous Solutions of Ionic Liquids: Microscopic Assembly.

    Science.gov (United States)

    Vicent-Luna, Jose Manuel; Dubbeldam, David; Gómez-Álvarez, Paula; Calero, Sofia

    2016-02-01

    Aqueous solutions of ionic liquids are of special interest, due to the distinctive properties of ionic liquids, in particular, their amphiphilic character. A better understanding of the structure-property relationships of such systems is hence desirable. One of the crucial molecular-level interactions that influences the macroscopic behavior is hydrogen bonding. In this work, we conduct molecular dynamics simulations to investigate the effects of ionic liquids on the hydrogen-bond network of water in dilute aqueous solutions of ionic liquids with various combinations of cations and anions. Calculations are performed for imidazolium-based cations with alkyl chains of different lengths and for a variety of anions, namely, [Br](-), [NO3](-), [SCN](-) [BF4](-), [PF6](-), and [Tf2N](-). The structure of water and the water-ionic liquid interactions involved in the formation of a heterogeneous network are analyzed by using radial distribution functions and hydrogen-bond statistics. To this end, we employ the geometric criterion of the hydrogen-bond definition and it is shown that the structure of water is sensitive to the amount of ionic liquid and to the anion type. In particular, [SCN](-) and [Tf2N](-) were found to be the most hydrophilic and hydrophobic anions, respectively. Conversely, the cation chain length did not influence the results.

  3. Modern electrochemical processes and technologies in ionic melts

    Directory of Open Access Journals (Sweden)

    Omelchuk A.

    2003-01-01

    Full Text Available An analysis of the known methods for the electrochemical purification of non-ferrous metals in ionic melts is presented. A comparative estimation of the results of the electrochemical purification of non-ferrous metals by different methods has been performed. The main regularities of the electrochemical behavior of non-ferrous metals in conventional and electrode micro-spacing electrolysis are presented. It has been found that when electrolyzing some metals, e. g. bismuth, gallium, there is either no mass exchange between the electrodes, or it occurs under filtration conditions. It has been shown that the electrode micro-spacing processes provide a high quality of non-ferrous metals purification at low specific consumption of electric power and reagents. The use of bipolar electrodes and β-alumina diaphragms hinders the transfer of metallic impurities from the anode to the cathode. The effects revealed were used to develop new processes for the separation of non-ferrous metal alloys in ionic melts; most of them have been put into practice in non-ferrous metallurgy.

  4. The Partitioning of Tungsten bwtween Aqueous Fluids and Silicate Melts

    Institute of Scientific and Technical Information of China (English)

    许永胜; 张本仁; 等

    1993-01-01

    An experimental study has been carried out to determine the partition coefficients of tungsten between aqueous fluids and granitic melts at 800℃ and 1.5kb with natural granite as the starting material,The effects of the solution on the partition coefficients of tungsten show a wequence of P>co32->B>H2O.The effects are limited(generally KD<0.3)and the tungsten shows a preferential trend toward the melt over the aqueous fiuid.The value of KD increases with increasing concentration of phosphorus;the KD increases first and then reduces with the concentration of CO32-;when temperature decreases,the KD between the solution of CO32- and the silicate melt increases,and that between the solution of B4O72- and the silicate melt decreases.The partition coefficients of phosphorus and sodium between fluids and silicate melts have been calculated from the concentrations of the elements in the melts.The KD value for phosphorus is 0.38 and that for sodium is 0.56.Evidence shows that the elements tend to become richer and richer in the melts.

  5. Low Melting Point and High Stability Polyoxomolybdate-based Ionic Liquids as Photocatalysts

    Institute of Scientific and Technical Information of China (English)

    DONG Tao; CHEN Fa-wang; CAO Min-hua; HU Chang-wen

    2011-01-01

    The polyoxometalate-imidazole ionic liquids(POM-ILs) with low melting points at 94.5 and 95.5 ℃,[Cnmim]4[Mo8O26](Cnmim=l-alkyl-3-methylimidazolium, n=12,14), have been successfully synthesized and characterized by DSC, single-crystal X-ray diffraction and TGA, etc. The two POM-ILs have relatively high stability with decomposing temperature up to about 347 and 344 ℃, respectively. Further photocatalytic performance was measured via the degradation of rhodamine B(RB) in aqueous solution. The experiments show that the conversion reached to 90% after 90 min under UV-light and the degradation efficiency depended on pH value, different dosages and so on. In addition, the catalysts can be recycled for several times without significant loss of activity.

  6. Olefin Epoxidation in Aqueous Phase Using Ionic-Liquid Catalysts.

    Science.gov (United States)

    Cokoja, Mirza; Reich, Robert M; Wilhelm, Michael E; Kaposi, Marlene; Schäffer, Johannes; Morris, Danny S; Münchmeyer, Christian J; Anthofer, Michael H; Markovits, Iulius I E; Kühn, Fritz E; Herrmann, Wolfgang A; Jess, Andreas; Love, Jason B

    2016-07-21

    Hydrophobic imidazolium-based ionic liquids (IL) act as catalysts for the epoxidation of unfunctionalized olefins in water using hydrogen peroxide as oxidant. Although the catalysts are insoluble in both the substrate and in water, surprisingly, they are very well soluble in aqueous H2 O2 solution, owing to perrhenate-H2 O2 interactions. Even more remarkably, the presence of the catalyst also boosts the solubility of substrate in water. This effect is crucially dependent on the cation design. Hence, the imidazolium perrhenates enable both the transfer of hydrophobic substrate into the aqueous phase, and serve as actual catalysts, which is unprecedented. At the end of the reaction and in absence of H2 O2 the IL catalyst forms a third phase next to the lipophilic product and water and can easily be recycled.

  7. Density and ionic structure of NdF_3-LiF melts

    Institute of Scientific and Technical Information of China (English)

    胡宪伟; 王兆文; 高炳亮; 石忠宁; 刘风国; 曹晓舟

    2010-01-01

    NdF3-LiF melts are commonly used in the electrolysis process of metallic neodymium production. Research on the density and ionic structure of the electrolyte is important for its close connection with the electrolysis mechanism and process. In this paper, the density of LiF-NdF3 melts was studied by the Archimedes method. The results showed that the density decreased with increasing temperature and LiF contents. The changing law was discussed and explained in terms of the micro ionic structure of the melts....

  8. Thermoreversible (Ionic-Liquid-Based) Aqueous Biphasic Systems.

    Science.gov (United States)

    Passos, Helena; Luís, Andreia; Coutinho, João A P; Freire, Mara G

    2016-02-04

    The ability to induce reversible phase transitions between homogeneous solutions and biphasic liquid-liquid systems, at pre-defined and suitable operating temperatures, is of crucial relevance in the design of separation processes. Ionic-liquid-based aqueous biphasic systems (IL-based ABS) have demonstrated superior performance as alternative extraction platforms, and their thermoreversible behaviour is here disclosed by the use of protic ILs. The applicability of the temperature-induced phase switching is further demonstrated with the complete extraction of two value-added proteins, achieved in a single-step. It is shown that these temperature-induced mono(bi)phasic systems are significantly more versatile than classical liquid-liquid systems which are constrained by their critical temperatures. IL-based ABS allow to work in a wide range of temperatures and compositions which can be tailored to fit the requirements of a given separation process.

  9. Thermoreversible (Ionic-Liquid-Based) Aqueous Biphasic Systems

    Science.gov (United States)

    Passos, Helena; Luís, Andreia; Coutinho, João A. P.; Freire, Mara G.

    2016-02-01

    The ability to induce reversible phase transitions between homogeneous solutions and biphasic liquid-liquid systems, at pre-defined and suitable operating temperatures, is of crucial relevance in the design of separation processes. Ionic-liquid-based aqueous biphasic systems (IL-based ABS) have demonstrated superior performance as alternative extraction platforms, and their thermoreversible behaviour is here disclosed by the use of protic ILs. The applicability of the temperature-induced phase switching is further demonstrated with the complete extraction of two value-added proteins, achieved in a single-step. It is shown that these temperature-induced mono(bi)phasic systems are significantly more versatile than classical liquid-liquid systems which are constrained by their critical temperatures. IL-based ABS allow to work in a wide range of temperatures and compositions which can be tailored to fit the requirements of a given separation process.

  10. Structural analysis of low melting organic salts: perspectives on ionic liquids.

    Science.gov (United States)

    Dean, Pamela M; Pringle, Jennifer M; MacFarlane, Douglas R

    2010-08-28

    Ionic liquid-forming salts often display low melting points (a lack of crystallisation at ambient temperature and pressure) as a result of decreased lattice energies in the crystalline state. Intermolecular interactions between the anion and cation, and the conformational states of each component of the salt, are of significant interest as many of the distinctive properties ascribed to ionic liquids are determined to a large extent by these interactions. Crystallographic analysis provides a direct insight into the spatial relationship between the cations and anions and provides a basis for an enhanced understanding of the physico-chemical relationship of the ionic liquids. This perspective article examines the crystallographic studies of relevance to ionic liquid-forming organic salts as a basis for the rational design and synthesis of novel ionic liquids. PMID:20593067

  11. Single Molecule Electrochemical Detection in Aqueous Solutions and Ionic Liquids.

    Science.gov (United States)

    Byers, Joshua C; Paulose Nadappuram, Binoy; Perry, David; McKelvey, Kim; Colburn, Alex W; Unwin, Patrick R

    2015-10-20

    Single molecule electrochemical detection (SMED) is an extremely challenging aspect of electroanalytical chemistry, requiring unconventional electrochemical cells and measurements. Here, SMED is reported using a "quad-probe" (four-channel probe) pipet cell, fabricated by depositing carbon pyrolytically into two diagonally opposite barrels of a laser-pulled quartz quadruple-barreled pipet and filling the open channels with electrolyte solution, and quasi-reference counter electrodes. A meniscus forms at the end of the probe covering the two working electrodes and is brought into contact with a substrate working electrode surface. In this way, a nanogap cell is produced whereby the two carbon electrodes in the pipet can be used to promote redox cycling of an individual molecule with the substrate. Anticorrelated currents generated at the substrate and tip electrodes, at particular distances (typically tens of nanometers), are consistent with the detection of single molecules. The low background noise realized in this droplet format opens up new opportunities in single molecule electrochemistry, including the use of ionic liquids, as well as aqueous solution, and the quantitative assessment and analysis of factors influencing redox cycling currents, due to a precisely known gap size. PMID:26398675

  12. An Increment Method of Calculation of Melting Temperatures of Ionic Crystals

    International Nuclear Information System (INIS)

    A new increment method for calculation of melting temperatures (Tm) of binary inorganic ionic crystalline compounds has been suggested. On the basis of rather simple mathematic relationship the Tm for the majority of these compounds can be defined by the accuracy of no less than 10%. (author)

  13. Evaluation of collective transport properties of ionic melts from molecular dynamics simulations

    Indian Academy of Sciences (India)

    Manish Agarwal; Charusita Chakravarty

    2009-09-01

    Molecular dynamics simulations of beryllium fluoride (BeF2) have been carried out in the canonical (NVT) ensemble using a rigid-ion potential model. The Green-Kubo formalism has been applied to compute viscosities and ionic conductivities of BeF2 melt. The computational parameters critical for reliably estimating these collective transport properties are shown to differ significantly for viscosity and ionic conductivity. In addition to the equilibrium values of these transport properties, structural relaxation times as well as high-frequency IR-active modes are computed from the pressure and charge-flux auto correlation functions (ACFs) respectively. It is shown that a network-forming ionic melt, such as BeF2, will display persistent oscillatory behaviour of the integral of the charge-flux ACF. By suitable Fourier transformation, one can show that these persistent oscillations correspond to highfrequency, infra-red active vibrations associated with local modes of the network.

  14. Thermodynamic studies of ionic hydration and interactions for amino acid ionic liquids in aqueous solutions at 298.15 K.

    Science.gov (United States)

    Dagade, Dilip H; Madkar, Kavita R; Shinde, Sandeep P; Barge, Seema S

    2013-01-31

    Amino acid ionic liquids are a special class of ionic liquids due to their unique acid-base behavior, biological significance, and applications in different fields such as templates in synthetic chemistry, stabilizers for biological macromolecules, etc. The physicochemical properties of these ionic liquids can easily be altered by making the different combinations of amino acids as anion along with possible cation modification which makes amino acid ionic liquids more suitable to understand the different kinds of molecular and ionic interactions with sufficient depth so that they can provide fruitful information for a molecular level understanding of more complicated biological processes. In this context, volumetric and osmotic coefficient measurements for aqueous solutions containing 1-ethyl-3-methylimidazolium ([Emim]) based amino acid ionic liquids of glycine, alanine, valine, leucine, and isoleucine are reported at 298.15 K. From experimental osmotic coefficient data, mean molal activity coefficients of ionic liquids were estimated and analyzed using the Debye-Hückel and Pitzer models. The hydration numbers of ionic liquids in aqueous solutions were obtained using activity data. Pitzer ion interaction parameters are estimated and compared with other electrolytes reported in the literature. The nonelectrolyte contribution to the aqueous solutions containing ionic liquids was studied by calculating the osmotic second virial coefficient through an application of the McMillan-Mayer theory of solution. It has been found that the second osmotic virial coefficient which includes volume effects correlates linearly with the Pitzer ion interaction parameter estimated independently from osmotic data as well as the hydrophobicity of ionic liquids. The enthalpy-entropy compensation effect, explained using the Starikov-Nordén model of enthalpy-entropy compensation, and partial molar entropy analysis for aqueous [Emim][Gly] solutions are made by using experimental Gibb

  15. Basic Ionic Liquid: A Reusable Catalyst for Knoevenagel Condensation in Aqueous Media

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    An efficient, environmentally friendly procedure was developed for the condensation of aldehydes/ketones and activated methylene compounds with basic ionic liquid as thecatalyst in water. This basic ionic liquid catalyst has a very high activity for Knoevenagel condensation to give the corresponding products in 70% -97% isolated yields under mild conditions. The basic ionic liquid catalyst in aqueous system can be reused for six times without any significant loss of activity.

  16. 1-Methyl-3-octylimidazolium Polyoxomolybdate Ionic Liquid with Low Melting Point and High Stability:Preparation and Photocatalytic Activity

    Institute of Scientific and Technical Information of China (English)

    DONG Tao; XU Yan-qing; CHEN Fa-wang; CHI Ying-nan; HU Chang-wen

    2011-01-01

    The polyoxometalate(POM)-imidazole ionic liquid(IL) [C8mim]2[Mo6O19](C8mim=l-methyl-3-octylimidazolium) with a low melting point of 82.6 ℃ was successfully prepared and characterized by FTIR, XPS, NMR, TG and so on. The polyoxomolybdate-based IL has high stability, and its decomposing temperature reaches 321 ℃,which is higher than that of l-alkyl-3-methylimidazolium halides IL. Further photocatalytic performances of the IL were measured via degrading dye rhodamine B(RB) in aqueous solution under the UV light irradiation. The experi ments show that the conversion of RB reaches 80.5% after 90 min under UV-light and the degradation efficiency de pends on the pH value of the solution, irradiation time and the dosage of the IL and so on.

  17. Revised Ionic Radii of Lanthanoid(III) Ions in Aqueous Solution

    International Nuclear Information System (INIS)

    A new set of ionic radii in aqueous solution has been derived for lanthanoid(III) cations starting from a very accurate experimental determination of the ion water distances obtained from extended X-ray absorption fine structure (EXAFS) data. At variance with previous results, a very regular. trend has been obtained, as expected for this series of elements. A general procedure to compute ionic radii in solution by combining the EXAFS technique and molecular dynamics (MD) structural data has been developed. This method can be applied to other ions allowing one to determine ionic radii in solution with an accuracy comparable to that of the Shannon crystal ionic radii. (authors)

  18. Polymerisation, basicity, oxidation state and their role in ionic modelling of silicate melts

    Directory of Open Access Journals (Sweden)

    R. Moretti

    2005-06-01

    Full Text Available In order to describe and quantify the reactivity of silicate melts, the ionic notation provided by the Temkin formalism has been historically accepted, giving rise to the study of melt chemical equilibria in terms of completely dissociated ionic species. Indeed, ionic modelling of melts works properly as long as the true extension of the anionic matrix is known. This information may be attained in the framework of the Toop-Samis (1962a,b model, through a parameterisation of the acid-base properties of the dissolved oxides. Moreover, by combining the polymeric model of Toop and Samis with the «group basicity» concept of Duffy and Ingram (1973, 1974a,b, 1976 the bulk optical basicity (Duffy and Ingram, 1971; Duffy, 1992 of molten silicates and glasses can be split into two distinct contributions, i.e. the basicity of the dissolved basic oxides and the basicity of the polymeric units. Application to practical cases, such as the assessment of the oxidation state of iron, require bridging of the energetic gap between the standard state of completely dissociated component (Temkin standard state and the standard state of pure melt component at P and T of interest. On this basis it is possible to set up a preliminary model for iron speciation in both anhydrous and hydrous aluminosilicate melts. In the case of hydrous melts, I introduce both acidic and basic dissociation of the water component, requiring the combined occurrence of H+ cations, OH- free anions and, to a very minor extent, of T-OH groups. The amphoteric behaviour of water revealed by this study is therefore in line with the earlier prediction of Fraser (1975.

  19. Spontaneous mass transfer and deposition of carbon and silicon on titanium in LiCl-Li ionic-electronic melts

    Directory of Open Access Journals (Sweden)

    Anfinogenov A.I.

    2003-01-01

    Full Text Available Coatings and powders containing separate phases of silicides and carbides have been obtained during the joint saturation of titanium by carbon and silicon in ionic-electronic melt Li- LiCl.

  20. Predicting critical temperatures of ionic and non-ionic fluids from thermophysical data obtained near the melting point.

    Science.gov (United States)

    Weiss, Volker C

    2015-10-14

    In the correlation and prediction of thermophysical data of fluids based on a corresponding-states approach, the critical temperature Tc plays a central role. For some fluids, in particular ionic ones, however, the critical region is difficult or even impossible to access experimentally. For molten salts, Tc is on the order of 3000 K, which makes accurate measurements a challenging task. Room temperature ionic liquids (RTILs) decompose thermally between 400 K and 600 K due to their organic constituents; this range of temperatures is hundreds of degrees below recent estimates of their Tc. In both cases, reliable methods to deduce Tc based on extrapolations of experimental data recorded at much lower temperatures near the triple or melting points are needed and useful because the critical point influences the fluid's behavior in the entire liquid region. Here, we propose to employ the scaling approach leading to universal fluid behavior [Román et al., J. Chem. Phys. 123, 124512 (2005)] to derive a very simple expression that allows one to estimate Tc from the density of the liquid, the surface tension, or the enthalpy of vaporization measured in a very narrow range of low temperatures. We demonstrate the validity of the approach for simple and polar neutral fluids, for which Tc is known, and then use the methodology to obtain estimates of Tc for ionic fluids. When comparing these estimates to those reported in the literature, good agreement is found for RTILs, whereas the ones for the molten salts NaCl and KCl are lower than previous estimates by 10%. The coexistence curve for ionic fluids is found to be more adequately described by an effective exponent of βeff = 0.5 than by βeff = 0.33. PMID:26472385

  1. Nitrogen distribution between aqueous fluids and silicate melts

    Science.gov (United States)

    Li, Yuan; Huang, Ruifang; Wiedenbeck, Michael; Keppler, Hans

    2015-02-01

    The partitioning of nitrogen between hydrous fluids and haplogranitic, basaltic, or albitic melts was studied at 1-15 kbar, 800-1200 °C, and oxygen fugacities (fO2) ranging from the Fe-FeO buffer to 3log units above the Ni-NiO buffer. The nitrogen contents in quenched glasses were analyzed either by electron microprobe or by secondary ion mass spectrometry (SIMS), whereas the nitrogen contents in fluids were determined by mass balance. The results show that the nitrogen content in silicate melt increases with increasing nitrogen content in the coexisting fluid at given temperature, pressure, and fO2. Raman spectra of the silicate glasses suggest that nitrogen species change from molecular N2 in oxidized silicate melt to molecular ammonia (NH3) or the ammonium ion (NH4+) in reduced silicate melt, and the normalized Raman band intensities of the nitrogen species linearly correlate with the measured nitrogen content in silicate melt. Elevated nitrogen contents in silicate melts are observed at reduced conditions and are attributed to the dissolution of NH3/NH4+. Measured fluid/melt partition coefficients for nitrogen (DNfluid/ melt) range from 60 for reduced haplogranitic melts to about 10 000 for oxidized basaltic melts, with fO2 and to a lesser extent melt composition being the most important parameters controlling the partitioning of nitrogen. Pressure appears to have only a minor effect on DNfluid/ melt in the range of conditions studied. Our data imply that degassing of nitrogen from both mid-ocean ridge basalts and arc magmas is very efficient, and predicted nitrogen abundances in volcanic gases match well with observations. Our data also confirm that nitrogen degassing at present magma production rates is insufficient to accumulate the atmosphere. Most of the nitrogen in the atmosphere must have degassed very early in Earth's history and degassing was probably enhanced by the oxidation of the mantle.

  2. Mixed system of ionic liquid and non-ionic surfactants in aqueous media: Surface and thermodynamic properties

    International Nuclear Information System (INIS)

    Highlights: • Interaction of ionic liquid and ethylene oxide based non-ionic surfactants in aqueous media. • Evaluation of various surface properties and thermodynamic parameters. • Micellar growth ensues from exothermic to endothermic with increase in temperature. • Micelle formation is enthalpy driven at low temperature and entropy driven at higher temperature. • The micellization power and adsorption proficiency decreased at high IL concentrations. - Abstract: The mixed system of ionic liquid (IL) tetraethyl ammonium tetrafluoroborate [TEA(BF4)] and numerous ethylene oxide based non-ionic surfactants in aqueous media were studied using surface tension, viscosity and dynamic light scattering (DLS) measurements. Various surface properties like critical micelle concentration (cmc), maximum surface excess concentration (Γmax), minimum surface area per surfactant molecule (Amin), surface tension at the cmc (γcmc), adsorption efficiency (pC20), and effectiveness of surface tension reduction (πcmc) as well as thermodynamic parameters of micellization have been determined. DLS and viscosity measurements revealed that the micellar growth was attributed to the bridged solvophilicity of the POE chain in surfactants at elevated temperatures. In most of the cases, the progression ensues from exothermic to endothermic with increase in temperature of the mixed system. Thermodynamic parameter indicates that the micelle formation process is enthalpy driven at low temperature and entropy driven at higher temperature

  3. Partitioning Behavior of Papain in Ionic Liquids-Based Aqueous Two-Phase Systems

    OpenAIRE

    Zhiwen Bai; Yanhong Chao; Meiling Zhang; Changri Han; Wenshuai Zhu; Yonghui Chang; Huaming Li; Yang Sun

    2013-01-01

    This paper attempts to study and optimize the affinity partitioning conditions of papain in an aqueous two-phase system (ATPS). The effect of the amount of ionic liquids (ILs), the concentration of K2HPO4, temperature, pH, and the volume of papain solution were discussed concretely. The optimum conditions were determined as ionic liquid was 1.4 g and K2HPO4 was 1.4 g, the extraction efficiency of papain co...

  4. Extraction of Biomolecules Using Phosphonium-Based Ionic Liquids + K3PO4 Aqueous Biphasic Systems

    OpenAIRE

    Louros, Cláudia L. S.; Cláudio, Ana Filipa M.; Neves, Catarina M. S. S.; Freire, Mara G.; Marrucho, Isabel M.; Jérôme Pauly; Coutinho, João A. P.

    2010-01-01

    Aqueous biphasic systems (ABS) provide an alternative and efficient approach for the extraction, recovery and purification of biomolecules through their partitioning between two liquid aqueous phases. In this work, the ability of hydrophilic phosphonium-based ionic liquids (ILs) to form ABS with aqueous K3PO4 solutions was evaluated for the first time. Ternary phase diagrams, and respective tie-lines and tie-lines length, formed by distinct phosphonium-based ILs, water, and K3PO4 at 298 K, we...

  5. Integral equation for the interfacial tension of liquid metal in contact with ionic melt

    CERN Document Server

    Kobelev, O A; Kobelev, Oleg A.; Kobelev, Alexandr V.

    2004-01-01

    The closed integral equations for the interfacial tension as a function of external polarization at the liquid metal - ionic melt interface are derived. The version of Popel'-Pavlov isotherm is applied to the analysis of electrocapillary curves (ecc), i.e. the dependences of interfacial tension on electrode potential. The interaction between adsorbed particles is taken into account within 'two exchange parameters' approximation. The type of the distribution of electric potential in the double electric layer (del) is assumed to be like 'in series connected capacitors'. The methods of solution are proposed for the analysis of the experimental ecc's.

  6. Reversible Sol-Gel Transitions in Aqueous Solutions of N-Isopropylacrylamide Ionic Copolymers

    Energy Technology Data Exchange (ETDEWEB)

    Krzyminski, Karol J.; Jasionowski, Marek; Gutowska, Anna

    2008-04-01

    Ionic copolymers of N-isopropylacrylamide (NIPA) exhibiting sol-gel transitions in aqueous solutions were investigated. The studies were aimed at understanding of the structure-property relationship in design of injectable, in situ forming gels for potential biomedical applications in delivery of therapeutics and tissue engineering. Aqueous solutions of NIPA ionic copolymers were found to flow freely at ambient temperatures and formed soft gels with controlled syneresis above 32°C, the lower critical solution temperature of NIPA. The sol-gel transitions and temperature dependent properties of the resulting gels were analyzed using dynamic rheometry, UV and IR spectrometry, and were found to be controlled by the molecular weight and composition of copolymers, ionization state of comonomers, and composition of aqueous solvent.

  7. Ion mixing, hydration, and transport in aqueous ionic systems

    International Nuclear Information System (INIS)

    The enhancement effect on the ion mobility of fluoride (and that of chloride) in a polycationic system, as the chloride content increases, is shown to also exist in other more simple ionic systems with cations such as the cesium ion and an organic ammonium ion. As the chloride content increases, in addition to the finding that there is more unbound water associated with the cation, we also observe that the average lifetime of a hydrogen bond decreases. This change to the hydrogen bonds is correlated to significant changes to both the structural and dynamical properties of water. The more disordered water structure and faster water dynamics are hypothesized to be also responsible for the enhanced ion mobilities. Furthermore, when either the chloride content or hydration level is changed, the self-diffusion constant of each co-ion changes by almost the same factor, implying the existence of a single universal transport mechanism that determines ion mobilities

  8. Probing Ionic Liquid Aqueous Solutions Using Temperature of Maximum Density Isotope Effects

    Directory of Open Access Journals (Sweden)

    Mohammad Tariq

    2013-03-01

    Full Text Available This work is a new development of an extensive research program that is investigating for the first time shifts in the temperature of maximum density (TMD of aqueous solutions caused by ionic liquid solutes. In the present case we have compared the shifts caused by three ionic liquid solutes with a common cation—1-ethyl-3-methylimidazolium coupled with acetate, ethylsulfate and tetracyanoborate anions—in normal and deuterated water solutions. The observed differences are discussed in terms of the nature of the corresponding anion-water interactions.

  9. Aqueous solutions of acidic ionic liquids for enhanced stability of polyoxometalate-carbon supercapacitor electrodes

    Science.gov (United States)

    Hu, Chenchen; Zhao, Enbo; Nitta, Naoki; Magasinski, Alexandre; Berdichevsky, Gene; Yushin, Gleb

    2016-09-01

    Nanocomposites based on polyoxometalates (POMs) nanoconfined in microporous carbons have been synthesized and used as electrodes for supercapacitors. The addition of the pseudocapacitance from highly reversible redox reaction of POMs to the electric double-layer capacitance of carbon lead to an increase in specific capacitance of ∼90% at 1 mV s-1. However, high solubility of POM in traditional aqueous electrolytes leads to rapid capacity fading. Here we demonstrate that the use of aqueous solutions of protic ionic liquids (P-IL) as electrolyte instead of aqueous sulfuric acid solutions offers an opportunity to significantly improve POM cycling stability. Virtually no degradation in capacitance was observed in POM-based positive electrode after 10,000 cycles in an asymmetric capacitor with P-IL aqueous electrolyte. As such, POM-based carbon composites may now present a viable solution for enhancing energy density of electrical double layer capacitors (EDLC) based on pure carbon electrodes.

  10. Cellulose/Gold Nanocrystal Hybrids via an Ionic Liquid/Aqueous Precipitation Route

    Directory of Open Access Journals (Sweden)

    Andreas Taubert

    2009-11-01

    Full Text Available Injection of a mixture of HAuCl4 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.

  11. Experiment and model for the surface tension of amine–ionic liquids aqueous solutions

    International Nuclear Information System (INIS)

    Highlights: • The surface tensions of MEA/DEA–ionic liquids aqueous solutions were measured. • The experiments were modeled satisfactorily by using a thermodynamic equation. • The temperature dependence of the surface tension was illustrated. • The effects of the mass fractions of MEA/DEA and ionic liquids were demonstrated. - Abstract: The surface tension (γ) of 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4])–monoethanolamine (MEA), 1-butyl-3-methylimidazolium bromide ([Bmim][Br])–MEA, [Bmim][BF4]–diethanolamine (DEA) and [Bmim][Br]–DEA aqueous solutions was measured by using the BZY-1 surface tension meter. The temperature ranged from (293.2 to 323.2) K. The mass fraction of amines and ionic liquids (ILS) respectively ranged from 0.15 to 0.30 and 0.05 to 0.10. A thermodynamic equation was proposed to model the surface tension of amines–ILS aqueous solutions and the calculated results agreed well with the experiments. The effects of temperature, mass fraction of amines and ILS on the surface tension were demonstrated on the basis of experiments and calculations

  12. Lithium chloride ionic association in dilute aqueous solution: a constrained molecular dynamics study

    Science.gov (United States)

    Zhang, Zhigang; Duan, Zhenhao

    2004-02-01

    Constrained molecular dynamics simulations were carried out to investigate the lithium chloride ionic associations in dilute aqueous solutions over a wide temperature range. Solvent mediated potentials of mean force have been carefully calculated at different thermodynamic conditions. Two intermediate states of ionic association can be well identified with an energy barrier from the oscillatory free energy profile. Clear pictures for the microscopic association structures are presented with a remarkable feature of strong hydration effect of lithium ion and the bridging role of its hydrating complex. Experimental association constants have been reasonably reproduced and a general trend of the increasing ionic association at high temperatures and low densities was observed. Additional simulations with different numbers of water molecules have been performed to check the possible artifacts introducing from periodic and finite size effects and confirm the reliability of our simulation results. Marginal differences of the simulated curves are believed to result from the significant compensation and canceling effect between the bare ionic forces and solvent induced mean force. Finally we confirmed the importance of accurate descriptions of dielectric properties of solvent in the ionic association study.

  13. Flexible EMI shielding materials derived by melt blending PVDF and ionic liquid modified MWNTs

    Science.gov (United States)

    Sharma, Maya; Sharma, Sukanya; Abraham, Jiji; Thomas, Sabu; Madras, Giridhar; Bose, Suryasarathi

    2014-09-01

    Nano composites of PVDF with ionic liquid [EMIM][TF2N] (IL) modified MWNTs were prepared by melt blending to design materials for EMI shielding applications. MWNTs and IL were mixed in two different ratios (1:1 and 1:5) to facilitate better dispersion of MWNTs in PVDF. It was observed that non-covalent interactions between IL and PVDF resulted in a better dispersion of CNTs and was consistent with increasing concentration of IL. Interestingly, IL modified MWNTs induced the formation of γ-phase crystals in PVDF, which was further confirmed by XRD, FTIR and DSC. Melt rheological measurements and DSC analysis revealed the plasticization effect of IL in PVDF composites further manifesting in a decrease in the storage modulus and the glass transition temperature. This phenomenal effect presumably led to better dispersion of IL modified MWNTs in PVDF further resulting in a significant improvement in electrical conductivity and structural properties. More interestingly, the elongational properties in the composites improved with IL modified MWNTs in striking contrast to MWNT filled PVDF composites. The ac conductivity of the composites reached about 10-3 S cm-1 with the addition of 2 wt% IL modified MWNTs (1:1). This further led to a high electro-magnetic interference (EMI) shielding effectiveness of about 20 dB at 2 wt% IL modified MWNTs. Such materials can further be explored for flexible, lightweight EMI shielding materials for a wide range of operating frequency.

  14. Dynamic Mass Transfer of Hemoglobin at the Aqueous/Ionic-Liquid Interface Monitored with Liquid Core Optical Waveguide.

    Science.gov (United States)

    Chen, Xuwei; Yang, Xu; Zeng, Wanying; Wang, Jianhua

    2015-08-01

    Protein transfer from aqueous medium into ionic liquid is an important approach for the isolation of proteins of interest from complex biological samples. We hereby report a solid-cladding/liquid-core/liquid-cladding sandwich optical waveguide system for the purpose of monitoring the dynamic mass-transfer behaviors of hemoglobin (Hb) at the aqueous/ionic liquid interface. The optical waveguide system is fabricated by using a hydrophobic IL (1,3-dibutylimidazolium hexafluorophosphate, BBimPF6) as the core, and protein solution as one of the cladding layer. UV-vis spectra are recorded with a CCD spectrophotometer via optical fibers. The recorded spectra suggest that the mass transfer of Hb molecules between the aqueous and ionic liquid media involve accumulation of Hb on the aqueous/IL interface followed by dynamic extraction/transfer of Hb into the ionic liquid phase. A part of Hb molecules remain at the interface even after the accomplishment of the extraction/transfer process. Further investigations indicate that the mass transfer of Hb from aqueous medium into the ionic liquid phase is mainly driven by the coordination interaction between heme group of Hb and the cationic moiety of ionic liquid, for example, imidazolium cation in this particular case. In addition, hydrophobic interactions also contribute to the transfer of Hb.

  15. Microfludic device for creating ionic strength gradients over DNA microarrays for efficient DNA melting studies and assay development

    DEFF Research Database (Denmark)

    Petersen, Jesper; Poulsen, Lena; Birgens, Henrik;

    2009-01-01

    specifically, we noted that (i) the two stringency modulators generated melting curves that could be compared, (ii) both led to increased assay robustness, and (iii) both were associated with difficulties in genotyping the same mutation. These findings demonstrate that ionic strength stringency buffers can be...... used instead of thermal gradients. Given the flexibility of design of ionic gradients, these can be created over all types of arrays, and encompass an attractive alternative to temperature gradients, avoiding curtailment of the size or spacing of subarrays on slides associated with temperature...

  16. Synthesis of Thiosalicylate based Hydrophobic Ionic Liquids and their Applications in Metal Extraction from aqueous solutions

    International Nuclear Information System (INIS)

    Two new hydrophobic ionic liquids were synthesized through ion exchange metathesis and characterized through spectral data and thermogravimetric analysis. These include 1,3- dibutylimidazolium thiosalicylate (BBIM)(TS) (1) and 1,3-dihexylimidazolium thiosalicylate (HHIM)(TS) (2). The application of these ILs in extraction of seven transition metal ions (Cr, Mn, Fe, Co, Ni, Cu and Zn) from aqueous solution has been investigated. High extraction efficiencies were observed. Extraction occurs rapidly at room temperature, no heating is required unlike previous reports. (HHIM)(TS) (2) Showed higher extraction efficiency in almost all metal ions tested as compare to (BBIM)(TS) (1). (author)

  17. Hydration properties and ionic radii of actinide(III) ions in aqueous solution

    International Nuclear Information System (INIS)

    Ionic radii of actinide(III) cations (from U(III) to Cf(III)) in aqueous solution have been derived for the first time starting from accurate experimental determination of the ion-water distances obtained by combining extended X-ray absorption fine structure (EXAFS) results and molecular dynamics (MD) structural data. A strong analogy has been found between the lanthanide and actinide series concerning hydration properties. The existence of a contraction of the An-O distance along the series has been highlighted, while no decrease of the hydration number is evident up to Cf(III). (authors)

  18. Aqueous Synthesis of CdTe Quantum Dot Using Dithiol-Functionalized Ionic Liquid

    Directory of Open Access Journals (Sweden)

    Suk Young Choi

    2012-01-01

    Full Text Available We report on an aqueous synthesis of cadmium telluride (CdTe nanocrystals by using dithiol-functionalized ionic liquids (dTFILs. The dTFILs were designed to have dithiol and vinylimidazolium functional groups and used as a ligand molecule of CdTe quantum dot (QD to utilize the bidendate chelate interaction afforded by the dithiol groups of dTFILs. The photoluminescence quantum yield of dTFIL-capped CdTe QDs reached up to ~40%, and their luminescent property was maintained for 8 weeks, suggesting an improved stability in water phase. This approach will provide a new synthetic route to the water soluble QDs.

  19. Simulations of mean ionic activity coefficients and solubilities in aqueous electrolyte solutions

    Science.gov (United States)

    Panagiotopoulos, Athanassios

    Aqueous electrolyte solutions play an important role in industrial, geochemical and biological applications. The mean ionic activity coefficients quantify the deviation of salt chemical potential from ideal solution behavior; experimental measurements are available for many salts over broad ranges of concentration and temperature, but there have been practically no prior simulation results, because if sampling difficulties for explicit-solvent electrolyte solutions. We have developed a new approach for determination of activity coefficients of aqueous electrolytes. Common fixed-point-charge models for water and ions are unable to reproduce simultaneously activity coefficients and solubilities. Polarizable models perform better, but still predict an incorrect temperature dependence of these properties. Work supported by the U.S. Department of Energy, Office of Basic Energy Science.

  20. Ludwig-Soret effect of non-ionic surfactant aqueous solution studied by beam deflection method

    Science.gov (United States)

    Maeda, Kousaku; Kita, Rio; Shinyashiki, Naoki; Yagihara, Shin

    2013-02-01

    We have studied the thermal diffusion of non-ionic surfactant aqueous solutions by a beam deflection method. The thermal diffusion of pentaethylene glycol monododecyl ether (C12E5) and hexaethylene glycol monododecyl ether (C12E6) is studied in the concentration range of 1.0-99.0 wt% and in the temperature range of 20.0-35.0 °C. A stable temperature gradient is applied to the solution, where solute molecules shift to the cold side of the solution for lowconcentration samples. The concentration dependence of the Soret coefficient ST of the C12E6 aqueous solution shows a sign inversion behavior. At all concentrations, the developed concentration gradient is proportionally related to the applied temperature gradient. The results confirm that the magnitude of ST has no temperature gradient dependence under the studied experimental conditions.

  1. Selective separation of protein and saccharides by ionic liquids aqueous two-phase systems

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In the present work,it was found that aqueous solution of a hydrophilic ionic liquid (IL),1-butyl-3-methylimidazolium dicyanamide ([C4mim][N(CN)2]),could be separated into an aqueous two-phase system (ATPS) by inorganic salts such as K2HPO4 and K3PO4.The top phase is IL-rich,while the bottom phase is phosphate-rich.It was shown that 82.7%-100% bovine serum albumin (BSA) could be enriched into the top phase and almost quantitative saccharides (arabinose,glucose,sucrose,raffinose or dextran) were preferentially extracted into the bottom phase in a single-step extraction by [C4mim][N(CN)2] + K2HPO4 ATPS.The extraction efficiency of BSA from the aqueous saccharide solutions was influenced by the molecular structure of saccharides.The conductivity,dynamic light scattering (DLS) and transmission electron microscopy (TEM) were combined to investigate the microstructure of the IL-rich top phase and the possible mechanism for the selective separation.It is suggested that the formation of the IL aggregate and the IL aggregate-BSA complex plays a significant role in the separation of BSA from aqueous saccharide solutions.This is the first example for the selective separation by ILs-based ATPSs.It is expected that these findings would have potential applications in bio-analysis,separation,and IL recycle.

  2. Extraction of Biomolecules Using Phosphonium-Based Ionic Liquids + K3PO4 Aqueous Biphasic Systems

    Directory of Open Access Journals (Sweden)

    Cláudia L. S. Louros

    2010-04-01

    Full Text Available Aqueous biphasic systems (ABS provide an alternative and efficient approach for the extraction, recovery and purification of biomolecules through their partitioning between two liquid aqueous phases. In this work, the ability of hydrophilic phosphonium-based ionic liquids (ILs to form ABS with aqueous K3PO4 solutions was evaluated for the first time. Ternary phase diagrams, and respective tie-lines and tie-lines length, formed by distinct phosphonium-based ILs, water, and K3PO4 at 298 K, were measured and are reported. The studied phosphonium-based ILs have shown to be more effective in promoting ABS compared to the imidazolium-based counterparts with similar anions. Moreover, the extractive capability of such systems was assessed for distinct biomolecules (including amino acids, food colourants and alkaloids. Densities and viscosities of both aqueous phases, at the mass fraction compositions used for the biomolecules extraction, were also determined. The evaluated IL-based ABS have been shown to be prospective extraction media, particularly for hydrophobic biomolecules, with several advantages over conventional polymer-inorganic salt ABS.

  3. Ionic Interactions for Aqueous Templating of Biofunctional Molecules in Block Copolymer Nanostructures

    Science.gov (United States)

    Olsen, Bradley; Kim, Bokyung; Lam, Christopher; Stewart-Sloan, Charlotte; Gkikas, Emmanouil

    2013-03-01

    The use of ionic interactions to direct both biomolecular templating and block copolymer self-assembly into nanopatterned films with only aqueous processing conditions is demonstrated using block copolymers containing both thermally responsive and pH responsive blocks. Reversible addition-fragmentation chain transfer (RAFT) polymerization is employed to synthesize diblock copolymers with one neutral thermoresponsive and one polycationic block and the pH-dependnent complexation between model proteins or biomimetic J-aggregating chromophores and the polycationic block is demonstrated. Spin casting is used to prepare nanostructured films from the protein-block copolymer and chromophore-block copolymer coacervates. After film formation, the lower critical solution temperature (LCST) of the thermoresponsive block allows the nanomaterial to be effectively immobilized in aqueous environments at physiological temperatures, enabling use of the materials for biomolecule immobilization and controlled release. In the case of protein nanotemplating, the ionic environment in which the protein is confined enables the majority of the protein (80%) to retain its activity, even after having been dehydrated in vacuum and confined in the thin film.

  4. The phase transport and reactions of γ-irradiated aqueous-ionic liquids

    International Nuclear Information System (INIS)

    A novel technology based on the transfer of chemical species across water/ionic liquid interfaces via specific complexation reactions is currently being considered for the separation and sequestration of metal ion contaminants from radioactive waste effluents in the nuclear fuel cycle. An ideal solvent for these applications should have a high intrinsic selectivity for a targeted metal or group of metals (e.g., trans-Pu actinides, lanthanides, or other fission products), an efficient switching mechanism (between complexation and decomplexation), and a high immiscibility with aqueous solutions. These characteristics must be maintained in the chemical, radiation, and mass transport environments present during the separation process. Ionic liquids (ILs) have an almost negligible vapour pressure and high thermal stability. Their ability to dissolve a wide range of substrate molecules and potential to be highly resilient in radiation fields make ILs particularly promising media. The separation efficiency of the biphasic system will depend on many parameters, including the aqueous oxidation state of the targeted metal ion, and the thermodynamics and kinetics of interfacial transport and metal-ligand complex formation at the water/IL interface or in the IL phase. The most uncertain and unstudied area for these applications is the effect of ionizing radiation on the stability and separation efficiency of the biphasic system. The present study investigates the effect of γ-radiation on gas/IL and water/IL interfacial stability and mass transfer with trihexyltetradecylphosphonium bis(trifluoromethyl-sulfonyl)imide, a phosphonium-based IL. The IL, in contact with either gas or water, was irradiated at a dose rate of 6.4 kGy·h-1. Gas-phase samples were analyzed by gas chromatography-mass spectrometry (GC-MS) and the changes in the IL and aqueous phases were monitored by conductivity measurements and Raman spectroscopy. In this paper we discuss these observations and their

  5. Secondary Confinement of Water Observed in Eutectic Melting of Aqueous Salt Systems in Nanopores.

    Science.gov (United States)

    Meissner, Jens; Prause, Albert; Findenegg, Gerhard H

    2016-05-19

    Freezing and melting of aqueous solutions of alkali halides confined in the cylindrical nanopores of MCM-41 and SBA-15 silica was probed by differential scanning calorimetry (DSC). We find that the confinement-induced shift of the eutectic temperature in the pores can be significantly greater than the shift of the melting temperature of pure water. Greatest shifts of the eutectic temperature are found for salts that crystallize as oligohydrates at the eutectic point. This behavior is explained by the larger fraction of pore volume occupied by salt hydrates as compared to anhydrous salts, on the assumption that precipitated salt constitutes an additional confinement for ice/water in the pores. A model based on this secondary confinement effect gives a good representation of the experimental data. Salt-specific secondary confinement may play a role in a variety of fields, from salt-impregnated advanced adsorbents and catalysts to the thermal weathering of building materials. PMID:27124392

  6. Design and development of single stage purification of papain using Ionic Liquid based aqueous two phase extraction system and its Partition coefficient studies

    OpenAIRE

    Senthilkumar Rathnasamy; R.Kumaresan2

    2013-01-01

    As an emerging trend in bioseparation, aqueous two phase extractions based on phosponium ionic liquid have been utilized in this work to extract papain from Carica papaya fruit latex and the same wascompared with conventional aqueous two phase extraction system. Factors affecting the partition coefficient of papain such as ionic liquid concentration, pH of the extraction system and temperature have been investigated. The optimization studies show that ionic liquid concentrations and pH are ma...

  7. Relative hydrophobicity between the phases and partition of cytochrome-c in glycine ionic liquids aqueous two-phase systems.

    Science.gov (United States)

    Wu, Changzeng; Wang, Jianji; Li, Zhiyong; Jing, Jun; Wang, Huiyong

    2013-08-30

    In this work, glycine ionic liquids tetramethylammonium glycine ([N1111][Gly]), tetraethylammonium glycine ([N2222][Gly]), tetra-n-butylammonium glycine ([N4444][Gly]), tetra-n-butylphosphonium glycine ([P4444][Gly]) and tetra-n-pentylammonium glycine ([N5555][Gly]) were synthesized and used to prepare aqueous two-phase systems (ATPSs) in the presence of K2HPO4. Binodal curves of such ATPSs and partition coefficients of a series of dinitrophenylated (DNP) amino acids in these ATPSs were determined at 298.15K to understand the effect of cationic structure of the ionic liquids on the phase-forming ability of glycine ionic liquids, relative hydrophobicity between the phases in the ionic liquids ATPSs, and polarity of the ionic liquids-rich phases. With the attempt to correlate the relative hydrophobicity of the phases in the ATPSs with their extraction capability for proteins, partition coefficients of cytochrome-c in the ATPSs were also determined. It was shown that partition coefficients of cytochrome-c were in the range from 2.83 to 20.7 under the studied pH conditions. Then, hydrophobic interactions between cytochrome-c and the ionic liquid are suggested to be the main driving force for the preferential partition of cytochrome-c in the glycine ionic liquid-rich phases of the ATPSs. Result derived from polarity of the ionic liquids-rich phases supports this mechanism.

  8. An experimental study of tin partition between melt and aqueous fluid in F/CI-coexisting magma

    Institute of Scientific and Technical Information of China (English)

    HU XiaoYan; BI XianWu; SHANG LinBo; HU RuiZhong; CAI GuoSheng; CHEN YouWei

    2009-01-01

    In order to investigate the formation mechanism of tin ores associated with F-bearing granite, an experimental study of tin partition between F-bearing granitic melt and coexisting HCI-bearing aqueous fluid was conducted at 850"C and 100MPa with fo2 approaching NNO. Geochemical behavior of tin was traced by changes in starting solid materials with different alumina saturation index ASl, in F content and in starting fluids of various HCl concentrations. The results show that DSn increases with ASl of melt and peraluminous melt is favorable for tin partition into aqueous fluid in the F/Cl-coexisting system. Aqueous fluid of higher HCl concentrations is advantageous for enrichment of tin. Furthermore,chlorine contents in glass run products correlate positively with F and CI contents in the magma. In the F/Cl-coexisting system, granitic melts with high F contents (>~-1 wt%) could extract and enrich tin in the melt which can serve as a reservoir for the formation of tin ores. However, the partition coefficient of tin would increase significantly when F contents in the melt were below 1 wt%. Therefore, the decrease of F contents is favorable to the partition of tin into aqueous fluid with high HCI contents, thus promoting deposition of hydrothermal tin ores.

  9. Absorption of carbon dioxide in aqueous solutions of imidazolium ionic liquids with carboxylate anions

    Energy Technology Data Exchange (ETDEWEB)

    Baj, Stefan; Krawczyk, Tomasz; Dabrowska, Aleksandra; Siewniak, Agnieszka [Silesian University of Technology, Gliwice (Poland); Sobolewski, Aleksander [Institute for Chemical Processing of Coal, Zabrze (Poland)

    2015-11-15

    The solubility of carbon dioxide at atmospheric pressure in aqueous mixtures of 1,3-alkyl substituted imidazolium ionic liquids (ILs) containing carboxylic anions was studied. The ILs showed increased solubility of CO{sub 2} with decreasing water concentration. The relationship between the CO{sub 2} concentration in solution and the mole fraction of water in the ILs describes a sigmoidal curve. The regression constants of a logistic function were used to quantitatively assess the absorbent capacity and the effect of water on CO{sub 2} absorption. ILs containing the most basic anions, such as pivalate, propionate and acetate, had the best properties. It was observed that the impact of water on absorption primarily depended on the cation structure. The best absorption performance was observed for 1,3-dibutylimidazolium pivalate and 1-butyl-3-methyl imidazolium acetate.

  10. Interactions of Aqueous Imidazolium-Based Ionic Liquid Mixtures with Solid-Supported Phospholipid Vesicles

    Science.gov (United States)

    Losada-Pérez, Patricia; Khorshid, Mehran; Renner, Frank Uwe

    2016-01-01

    Despite the environmentally friendly reputation of ionic liquids (ILs), their safety has been recently questioned given their potential as cytotoxic agents. The fundamental mechanisms underlying the interactions between ILs and cells are less studied and by far not completely understood. Biomimetic films are here important biophysical model systems to elucidate fundamental aspects and mechanisms relevant for a large range of biological interaction ranging from signaling to drug reception or toxicity. Here we use dissipative quartz crystal microbalance QCM-D to examine the effect of aqueous imidazolium-based ionic liquid mixtures on solid-supported biomimetic membranes. Specifically, we assess in real time the effect of the cation chain length and the anion nature on a supported vesicle layer of the model phospholipid DMPC. Results indicate that interactions are mainly driven by the hydrophobic components of the IL, which significantly distort the layer and promote vesicle rupture. Our analyses evidence the gradual decrease of the main phase transition temperature upon increasing IL concentration, reflecting increased disorder by weakening of lipid chain interactions. The degree of rupture is significant for ILs with long hydrophobic cation chains and large hydrophobic anions whose behavior is reminiscent of that of antimicrobial peptides. PMID:27684947

  11. Colloidal Behavior of Aqueous Montmorillonite Suspensions in the Presence of Non-ionic Polymer

    Institute of Scientific and Technical Information of China (English)

    Mourad Gareche[1; Nadjet Azril[1; Leila Saoudi[1; Jean Charles Dupin[2; Ahmed Allal[2; Noureddine Zeraibi[1

    2015-01-01

    In this paper, we characterized at first, the rheological behavior of the bentonite suspensions and the aqueous solutions of PEO (polyethylene oxide). Then we are going to investigate the influence of this polymer in a water-based drilling fluid model (6% of bentonite suspension). The objective is to exhibit how the non-ionic polymer with molecular weight 6×103 g/mol, of varying concentration mass (0.7%, 1%, 2% and 3%) significantly alter the rheological properties (yield stress, viscosity, loss and elastic modulus) of the bentonite suspensions. The rheological measurements made in simple shear and in dynamic on the mixture (water-bentonite-PEO), showed rheological properties of bentonite suspensions both in the presence and absence of non-ionic polymer. The PEO presents an affinity for the bentonite particles slowing down their kinetic aggregation. The analysis by XRD (X-rays diffraction) also allowed understanding the structure of this mixture. It had revealed the intercalation between of the clay platelets on one hand, and the links bridges assured by the chains of polymer between bentonite particles beyond a critical concentration in PEO on the other hand.

  12. Improved extraction of fluoroquinolones with recyclable ionic-liquid-based aqueous biphasic systems†

    Science.gov (United States)

    Almeida, Hugo F. D.; Freire, Mara G.; Marrucho, Isabel M.

    2016-01-01

    In the past few years, the improvement of advanced analytical tools allowed to confirm the presence of trace amounts of metabolized and unchanged active pharmaceutical ingredients (APIs) in wastewater treatment plants (WWTPs) as well as in freshwater surfaces. It is known that the continuous contact with APIs, even at very low concentrations (ng L−1–μg L−1), leads to serious human health problems. In this context, this work shows the feasibility of using ionic-liquid-based aqueous biphasic systems (IL-based ABS) in the extraction of quinolones present in aqueous media. In particular, ABS composed of imidazolium- and phosphonium-based ILs and aluminium-based salts (already used in water treatment plants) were evaluated in one-step extractions of six fluoroquinolones (FQs), namely ciprofloxacin, enrofloxacin, moxifloxacin, norfloxacin, ofloxacin and sarafloxacin, and extraction efficiencies up to 98% were obtained. Despite the large interest devoted to IL-based ABS as extractive systems of outstanding performance, their recyclability/reusability has seldomly been studied. An efficient extraction/cleaning process of the IL-rich phase is here proposed by FQs induced precipitation. The recycling of the IL and its further reuse without losses in the ABS extractive performance for FQs were established, as confirmed by the four consecutive removal/extraction cycles evaluated. This novel recycling strategy supports IL-based ABS as sustainable and cost-efficient extraction platforms.

  13. Design of functional guanidinium ionic liquid aqueous two-phase systems for the efficient purification of protein

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Xueqin; Wang, Yuzhi, E-mail: wyzss@hnu.edu.cn; Zeng, Qun; Chen, Jing; Huang, Yanhua; Xu, Kaijia

    2014-03-01

    Graphical abstract: - Highlights: • A series of novel cationic functional hexaalkylguanidinium ionic liquids and anionic functional tetraalkylguanidinium ionic liquids have been synthesized. • Functional guanidinium ionic liquid aqueous two-phase systems have been first designed for the purification of protein. • Mechanisms and performances of the process were researched. • Simple, green, safety and presents better purified ability than ordinary process. • A potential efficient platform for protein purification and related studies. - Abstract: A series of novel cationic functional hexaalkylguanidinium ionic liquids and anionic functional tetraalkylguanidinium ionic liquids have been devised and synthesized based on 1,1,3,3-tetramethylguanidine. The structures of the ionic liquids (ILs) were confirmed by {sup 1}H nuclear magnetic resonance ({sup 1}H NMR) and 13C nuclear magnetic resonance (13C NMR) and the production yields were all above 90%. Functional guanidinium ionic liquid aqueous two-phase systems (FGIL-ATPSs) have been first designed with these functional guanidinium ILs and phosphate solution for the purification of protein. After phase separation, proteins had transferred into the IL-rich phase and the concentrations of proteins were determined by measuring the absorbance at 278 nm using an ultra violet visible (UV–vis) spectrophotometer. The advantages of FGIL-ATPSs were compared with ordinary ionic liquid aqueous two-phase systems (IL-ATPSs). The proposed FGIL-ATPS has been applied to purify lysozyme, trypsin, ovalbumin and bovine serum albumin. Single factor experiments were used to research the effects of the process, such as the amount of ionic liquid (IL), the concentration of salt solution, temperature and the amount of protein. The purification efficiency reaches to 97.05%. The secondary structure of protein during the experimental process was observed upon investigation using UV–vis spectrophotometer, Fourier-transform infrared

  14. Aqueous interfaces with hydrophobic room-temperature ionic liquids: a molecular dynamics study.

    Science.gov (United States)

    Chaumont, A; Schurhammer, R; Wipff, G

    2005-10-13

    We report a molecular dynamics study of the interface between water and (macroscopically) water-immiscible room-temperature ionic liquids "ILs", composed of PF6(-) anions and butyl- versus octyl-substituted methylimidazolium+ cations (noted BMI+ and OMI+). Because the parameters used to simulate the pure ILs were found to exaggerate the water/IL mixing, they have been modified by scaling down the atomic charges, leading to better agreement with the experiment. The comparison of [OMI][PF6] versus [BMI][PF6] ILs demonstrates the importance of the N-alkyl substituent on the extent of solvent mixing and on the nature of the interface. With the most hydrophobic [OMI][PF6] liquid, the "bulk" IL phase is dryer than with the [BMI][PF6] liquid. At the interface, the OMI+ cations retain direct contacts with the bulk IL, whereas the more hydrophilic PF6(-) anions gradually dilute in the local water micro-environment and are thus isolated from the "bulk" IL. The interfacial OMI+ cations are ordered with their imidazolium moiety pointing toward the aqueous side and their octyl chains toward the IL side of the interface. With the [BMI][PF6] liquid, the system gradually evolves from an IL-rich to a water-rich medium, leading to an ill-defined interfacial domain with high intersolvent mixing. As a result, the BMI+ cations are isotropically oriented "at the interface". Because the imidazolium cations are more hydrophobic than the PF6(-) anions, the charge distribution at the interface is heterogeneous, leading to a positive electrostatic potential at the interface with the two studied ILs. Mixing-demixing simulations on [BMI][PF6]/water mixtures are also reported, comparing Ewald versus reaction field treatments of electrostatics. Phase separation is very slow (at least 30 ns), in marked contrast with mixtures involving classical organic liquids, which separate in less than 0.5 ns at the microscopic level. The results allow us to better understand the specificity of the aqueous

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

    Energy Technology Data Exchange (ETDEWEB)

    Baker, Gary A [ORNL; Heller, William T [ORNL

    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.

  16. Self-assembly and antimicrobial activity of long-chain amide-functionalized ionic liquids in aqueous solution.

    Science.gov (United States)

    Garcia, M Teresa; Ribosa, Isabel; Perez, Lourdes; Manresa, Angeles; Comelles, Francesc

    2014-11-01

    Surface active amide-functionalized ionic liquids (ILs) consisting of a long alkyl chain (C6C14) connected to a polar head group (methylimidazolium or pyridinium cation) via an amide functional group were synthesized and their thermal stability, micellar properties and antimicrobial activity in aqueous solution investigated. The incorporation of an amide group increased the thermal stability of the functionalized ionic liquids compared to simple alkyl chain substituted ionic liquids. The surface activity and aggregation behaviour in aqueous solution of amide-functionalized ionic liquids were examined by tensiometry, conductivity and spectrofluorimetry. Amide-functionalized ILs displayed surface activity and their critical micelle concentration (cmc) in aqueous media decreased with the elongation of the alkyl side chain as occurs for typical surfactants. Compared to non-functionalized ILs bearing the same alkyl chain, ionic liquids with an amide moiety possess higher surface activity (pC20) and lower cmc values. The introduction of an amide group in the hydrophobic chain close to the polar head enhances adsorption at the air/water interface and micellization which could be attributed to the H-bonding in the headgroup region. The antimicrobial activity was evaluated against a panel of representative Gram-negative and Gram-positive bacteria and fungi. Amide-functionalized ILs with more than eight carbon atoms in the side chain showed broad antimicrobial activity. Antibacterial activities were found to increase with the alkyl chain length being the C12 homologous the most effective antimicrobial agents. The introduction of an amide group enhanced significantly the antifungal activity as compared to non-functionalized ILs.

  17. Aqueous two phase system based on ionic liquid for isolation of quinine from human plasma sample.

    Science.gov (United States)

    Flieger, J; Czajkowska-Żelazko, A

    2015-01-01

    Aqueous two phase system was applied for selective extraction of quinine from human plasma. Bi-phase was constructed from ionic liquid: butyl-methyl-imidazolium chloride after addition kosmotropic salts K₃PO₄ or KH₂PO₄. Quinine was determined in plasma samples after drinking of tonic containing quinine. Determination was performed by HPLC on 5-μm Zorbax SB-CN column and eluent containing 40% acetonitrile (v/v), 20 mM phosphate buffer at pH 3 and 40 mM NaPF₆ using external standard method. The spectrophotometric detection was set λ=214 nm. Selective fluorescence detection was performed at excitation of 325 nm and emission of 375 nm. Proposed strategy provides suitable sample purification and gives extraction yields in the range of 89-106%. The determination coefficient (R(2)) has a value ≥0.997 in the range of 50-800 ng/ml quinine concentration. The limit of quantification was set at 27.9 ng/ml and the detection limit was found to be 8.4 ng/ml under fluorescence detection.

  18. Electrochemical, computational and spectroscopic investigation on local environment of plutonium in ionic liquid and aqueous medium. A comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Sengupta, Arijit; Murali, Mallekav S.; Mohapatra, Prasanta Kumar [Bhabha Atomic Research Centre Trombay, Mumbai (India). Radiochemistry Div.; Ali, Sk. Musharaf; Shenoy, Kalsanka Trivikram [Bhabha Atomic Research Centre Trombay, Mumbai (India). Chemical Engineering Div.

    2016-07-01

    With an aim to understand the nature of species, cyclic voltammetry (CV) of Pu(IV) in dilute HBr and in a room temperature ionic liquid (RTIL), 1-octyl-3-methylimidazolium bromide (C{sub 8}mimBr) was carried out. Shifts of cathodic and anodic peak potentials of Pu(IV) cyclic voltammograms were observed towards negative potentials in the extended electrochemical window for ionic liquid medium compared to 2 M HBr. The diffusion coefficient of the most likely species of Pu(IV) in aqueous medium was found to be greater than that of the corresponding species in ionic liquid while the activation energy showed reverse trend. The Pu(IV)/Pu(III) redox reaction was found to be exothermic in aqueous medium while it was endothermic in C{sub 8}mimBr. The redox reaction was found to be quasi reversible for both the media while the extent of irreversibility was more in ionic liquid. UV-Vis spectroscopy of Pu in these media showed significant differences in the peak positions and their relative intensities, indicating the possible differences in the interactions of Pu(IV) with the solvent molecules resulting in speciation differences. A new prominent peak was observed in RTIL which could be for a new species of Pu(IV). Computational studies were also carried out to understand the solvation of Pu and the possibility of thermodynamic conversion from Pu(IV) to Pu(III).

  19. Electrochemical, computational and spectroscopic investigation on local environment of plutonium in ionic liquid and aqueous medium. A comparative study

    International Nuclear Information System (INIS)

    With an aim to understand the nature of species, cyclic voltammetry (CV) of Pu(IV) in dilute HBr and in a room temperature ionic liquid (RTIL), 1-octyl-3-methylimidazolium bromide (C8mimBr) was carried out. Shifts of cathodic and anodic peak potentials of Pu(IV) cyclic voltammograms were observed towards negative potentials in the extended electrochemical window for ionic liquid medium compared to 2 M HBr. The diffusion coefficient of the most likely species of Pu(IV) in aqueous medium was found to be greater than that of the corresponding species in ionic liquid while the activation energy showed reverse trend. The Pu(IV)/Pu(III) redox reaction was found to be exothermic in aqueous medium while it was endothermic in C8mimBr. The redox reaction was found to be quasi reversible for both the media while the extent of irreversibility was more in ionic liquid. UV-Vis spectroscopy of Pu in these media showed significant differences in the peak positions and their relative intensities, indicating the possible differences in the interactions of Pu(IV) with the solvent molecules resulting in speciation differences. A new prominent peak was observed in RTIL which could be for a new species of Pu(IV). Computational studies were also carried out to understand the solvation of Pu and the possibility of thermodynamic conversion from Pu(IV) to Pu(III).

  20. Direct extraction of genomic DNA from maize with aqueous ionic liquid buffer systems for applications in genetically modified organisms analysis.

    Science.gov (United States)

    Gonzalez García, Eric; Ressmann, Anna K; Gaertner, Peter; Zirbs, Ronald; Mach, Robert L; Krska, Rudolf; Bica, Katharina; Brunner, Kurt

    2014-12-01

    To date, the extraction of genomic DNA is considered a bottleneck in the process of genetically modified organisms (GMOs) detection. Conventional DNA isolation methods are associated with long extraction times and multiple pipetting and centrifugation steps, which makes the entire procedure not only tedious and complicated but also prone to sample cross-contamination. In recent times, ionic liquids have emerged as innovative solvents for biomass processing, due to their outstanding properties for dissolution of biomass and biopolymers. In this study, a novel, easily applicable, and time-efficient method for the direct extraction of genomic DNA from biomass based on aqueous-ionic liquid solutions was developed. The straightforward protocol relies on extraction of maize in a 10 % solution of ionic liquids in aqueous phosphate buffer for 5 min at room temperature, followed by a denaturation step at 95 °C for 10 min and a simple filtration to remove residual biopolymers. A set of 22 ionic liquids was tested in a buffer system and 1-ethyl-3-methylimidazolium dimethylphosphate, as well as the environmentally benign choline formate, were identified as ideal candidates. With this strategy, the quality of the genomic DNA extracted was significantly improved and the extraction protocol was notably simplified compared with a well-established method.

  1. Density and sound speed study of hydration of 1-butyl-3-methylimidazolium based amino acid ionic liquids in aqueous solutions

    International Nuclear Information System (INIS)

    Highlights: • Apparent and partial molar volumes of aqueous AAILs at T = (293.15 to 313.15) K. • Isothermal and adiabatic compressibilities of AAILs in aqueous solution at T = 298.15 K. • Method for direct estimation of hydration numbers due to electrostriction is given. • Internal pressure and hydration numbers for AAILs at T = 298.15 K. • Results obtained demonstrate kosmotropic behavior of AAILs. - Abstract: Amino acid ionic liquids (AAILs) have huge potential in the field of protein chemistry, enzymatic reactions, templates for synthetic study etc. which is due to their distinctive properties like unique acid-base characteristics, tunable hydrophobicity, hydrogen bonding ability and strong hydration effects. To explore the field of bio-ionic liquids for its real life applications and sustainable technology development, it is essential to have better understanding of these newly researched liquid salts in life’s most chosen medium, i.e. in aqueous medium, through study of their physicochemical properties in aqueous solutions. In this context, we are reporting herewith measurements and analysis of volumetric properties in the temperature range of (293.15 to 313.25) K and acoustic properties at 298.15 K in the concentration range of (0.05 to 0.5) mol · kg−1 for aqueous solutions of 1-butyl-3-methylimidazolium [Bmim] based amino acid ionic liquids, prepared from glycine, L-alanine, L-valine, L-leucine and L-isoleucine. The experimental density and sound speed data were used to obtain apparent, partial and limiting molar volumes as well as isentropic and isothermal compressibility properties. These data have been further used to understand electrostriction as well as concentration dependence of internal pressure. The hydration numbers for AAILs in aqueous medium were estimated from compressibility data using Passynski method and the estimated ionic hydration numbers are compared with those obtained using activity data. The results are explained in

  2. Thin liquid films from aqueous solutions of non-ionic polymeric surfactants.

    Science.gov (United States)

    Exerowa, Dotchi; Platikanov, Dimo

    2009-01-01

    The conditions of formation and stability of foam, emulsion, and wetting films from aqueous solutions of non-ionic polymeric surfactants have been established. Two types of polymeric surfactants - PEO-PPO-PEO three-block copolymers (A-B-A type) and hydrophobically modified inulin graft polymer (AB(n) type) - have been explored. Information about surface forces and nanoscale phenomena in aqueous films containing polymeric surfactants was obtained using the micro-interferometric technique and the Thin Liquid Film-Pressure Balance Technique. Two types of surface forces, which determine the stability of the foam and emulsion films, have been distinguished, namely: DLVO-forces at low electrolyte concentrations and non-DLVO-forces at high electrolyte concentrations. Non-DLVO-forces are steric surface forces of the brush-to-brush and loop-to-loop interaction type according to De Gennes. A substantial difference in the behavior of these two film types has been established and in the case of O/W emulsion films transitions to Newton black film (NBF) have been observed. These films are very stable and so are the respective emulsions. In contrast the wetting films are relatively thicker compared to emulsion films, and their thickness depends on the concentration of the AB(n) polymeric surfactant. The steric repulsion of the loops and tails of the polymeric surfactant determine the film thickness of wetting films on a hydrophilic solid surface. For solid surfaces with different degrees of hydrophobicity the wetting films are stable only at high polymer concentrations and low degree of hydrophobicity. Otherwise the films are unstable and rupture. Two types of bilayer emulsion films have been distinguished for the first time. One type is related to the brush-to-brush or loop-to-loop interactions according to De Gennes. The other type is a NBF where the forces are also steric between strongly hydrated brush and loops but they are short-range forces acting in a two

  3. Dissolution of metal oxides in an acid-saturated ionic liquid solution and investigation of the back-extraction behaviour to the aqueous phase

    OpenAIRE

    Wellens, Sil; Vander Hoogerstraete, Tom; Möller, Claudia; Thijs, Ben; Luyten, Jan; Binnemans, Koen

    2014-01-01

    The dissolution of metal oxides in an acid-saturated ionic liquid, followed by selective stripping of the dissolved metal ions to an aqueous phase is proposed as a new ionometallurgical approach for the processing of metals in ionic liquids. The hydrophobic ionic liquid trihexyl(tetradecyl)phosphonium chloride (Cyphos IL 101) saturated with a concentrated aqueous hydrochloric acid solution was used to dissolve CaO, NiO, MnO, CoO, CuO, ZnO and Fe2O3. It was found that nickel(II) and calcium...

  4. Extraction of Phthalic Acid from Aqueous Solution by Using Ionic Liquids: A Quantum Chemical Approach

    OpenAIRE

    Pilli, S; Mohanty, Kaustubha; Banerjee, Tamal

    2014-01-01

    Phthalic acid is an industrial chemical and it comes under the domain of endocrine disrupting chemicals (EDCs). Green solvents such as ionic liquids (ILs) posses good extractable capabilities for EDCs. COSMO–RS methodology is a widely accepted method for the design or selection of ionic liquids. COSMO–RS is a quantum chemical based method based on COSMO polarization charge densities. In this work the model has been used to screen the potential ionic liquids for the removal of phthalic acid fr...

  5. A resolution approach of racemic phenylalanine with aqueous two-phase systems of chiral tropine ionic liquids.

    Science.gov (United States)

    Wu, Haoran; Yao, Shun; Qian, Guofei; Yao, Tian; Song, Hang

    2015-10-30

    Aqueous two-phase systems (ATPS) based on tropine type chiral ionic liquids and inorganic salt solution were designed and prepared for the enantiomeric separation of racemic phenylalanine. The phase behavior of IL-based ATPS was comprehensive investigated, and phase equilibrium data were correlated by Merchuk equation. Various factors were also systematically investigated for their influence on separation efficiency. Under the appropriate conditions (0.13g/g [C8Tropine]pro, 35mg/g Cu(Ac)2, 20mg/g d,l-phenylalanine, 0.51g/g H2O and 0.30g/g K2HPO4), the enantiomeric excess value of phenylalanine in solid phase (mainly containing l-enantiomer) was 65%. Finally, the interaction mechanism was studied via 1D and 2D NMR. The results indicate that d-enantiomer of phenylalanine interacts more strongly with chiral ILs and Cu(2+) based on the chiral ion-pairs space coordination mechanism, which makes it tend to remain in the top IL-rich phase. By contrast, l-enantiomer is transferred into the solid phase. Above chiral ionic liquids aqueous two-phase systems have demonstrated obvious resolution to racemic phenylalanine and could be promising alterative resolution approach for racemic amino acids in aqueous circumstance.

  6. Femtosecond laser pulse driven melting in gold nanorod aqueous colloidal suspension: identification of a transition from stretched to exponential kinetics.

    Science.gov (United States)

    Li, Yuelin; Jiang, Zhang; Lin, Xiao-Min; Wen, Haidan; Walko, Donald A; Deshmukh, Sanket A; Subbaraman, Ram; Sankaranarayanan, Subramanian K R S; Gray, Stephen K; Ho, Phay

    2015-01-30

    Many potential industrial, medical, and environmental applications of metal nanorods rely on the physics and resultant kinetics and dynamics of the interaction of these particles with light. We report a surprising kinetics transition in the global melting of femtosecond laser-driven gold nanorod aqueous colloidal suspension. At low laser intensity, the melting exhibits a stretched exponential kinetics, which abruptly transforms into a compressed exponential kinetics when the laser intensity is raised. It is found the relative formation and reduction rate of intermediate shapes play a key role in the transition. Supported by both molecular dynamics simulations and a kinetic model, the behavior is traced back to the persistent heterogeneous nature of the shape dependence of the energy uptake, dissipation and melting of individual nanoparticles. These results could have significant implications for various applications such as water purification and electrolytes for energy storage that involve heat transport between metal nanorod ensembles and surrounding solvents.

  7. Femtosecond Laser Pulse Driven Melting in Gold Nanorod Aqueous Colloidal Suspension: Identification of a Transition from Stretched to Exponential Kinetics

    Science.gov (United States)

    Li, Yuelin; Jiang, Zhang; Lin, Xiao-Min; Wen, Haidan; Walko, Donald A.; Deshmukh, Sanket A.; Subbaraman, Ram; Sankaranarayanan, Subramanian K. R. S.; Gray, Stephen K.; Ho, Phay

    2015-01-01

    Many potential industrial, medical, and environmental applications of metal nanorods rely on the physics and resultant kinetics and dynamics of the interaction of these particles with light. We report a surprising kinetics transition in the global melting of femtosecond laser-driven gold nanorod aqueous colloidal suspension. At low laser intensity, the melting exhibits a stretched exponential kinetics, which abruptly transforms into a compressed exponential kinetics when the laser intensity is raised. It is found the relative formation and reduction rate of intermediate shapes play a key role in the transition. Supported by both molecular dynamics simulations and a kinetic model, the behavior is traced back to the persistent heterogeneous nature of the shape dependence of the energy uptake, dissipation and melting of individual nanoparticles. These results could have significant implications for various applications such as water purification and electrolytes for energy storage that involve heat transport between metal nanorod ensembles and surrounding solvents. PMID:25634673

  8. Investigation on the extraction of strontium ions from aqueous phase using crown ether-ionic liquid systems

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The extraction of strontium ions using DCH18C6 as the extractant and various ionic liquids(ILs) as solvents has been investigated.The distribution ratio of Sr2+ can reach as high as 103 under certain conditions,much larger than that in DCH18C6/n-octanol system.The extraction capacity depends greatly on the structure of ionic liquids.In Ils-based extraction systems,the extraction efficiency of strontium ions is reduced by increasing the concentration of nitric acid and can also be influenced directly by the presence of Na+ and K+ in the aqueous phase.It is confirmed that the extraction proceeds mainly via a cation-exchange mechanism.

  9. Partitioning of F Between Aqueous Fluids and Albite Granite Melt and Its Petrogenetic and Metallogenetic SignifiCance

    Institute of Scientific and Technical Information of China (English)

    熊小林; 朱金初; 等

    1998-01-01

    The fluid/melt partitioning experiments on fluorine were carried out in the system albite-H2O-HF at P=100MPa,770℃≤T≤800℃and wt 2%-6% conditions.The concentrations of fluorine in quenched glasses(melt) were determined by electron microprobe and those of flusorine in the coexisting aqueous fluid were calculated by the method of mass balance The result shows that the fluorine was concentrated in graniteic melt relative to the coexisting fluid.The partition coefficient DF(wtFF1/wtFMt)ranges from 0.35to 0.89,It increases with increasing fluorine content in the system,this means that there is not just one single value of partition coefficicent for fluorine in the granitic melt-fluid system.The partitioning behavior of fluorine in this system depends critically on fluorine and proton(H+) concentrations.Our data suggest that F-rich granitic melts exist in nature and that fluorine may not be an important complexing agent of metal elements in F-bearing fluids.

  10. Molecular simulation of homogeneous nucleation of crystals of an ionic liquid from the melt

    International Nuclear Information System (INIS)

    The homogeneous nucleation of crystals of the ionic liquid [dmim+][Cl−] from its supercooled liquid phase in the bulk (P = 1 bar, T = 340 K, representing a supercooling of 58 K) was studied using molecular simulations. The string method in collective variables [Maragliano et al., J. Chem. Phys. 125, 024106 (2006)] was used in combination with Markovian milestoning with Voronoi tessellations [Maragliano et al., J. Chem. Theory Comput. 5, 2589–2594 (2009)] and order parameters for molecular crystals [E. E. Santiso and B. L. Trout, J. Chem. Phys. 134, 064109 (2011)] to sketch a minimum free energy path connecting the supercooled liquid and the monoclinic crystal phases, and to determine the free energy and the rates involved in the homogeneous nucleation process. The physical significance of the configurations found along this minimum free energy path is discussed with the help of calculations based on classical nucleation theory and with additional simulation results obtained for a larger system. Our results indicate that, at a supercooling of 58 K, the liquid has to overcome a free energy barrier of the order of 60 kcal/mol and to form a critical nucleus with an average size of about 3.6 nm, before it reaches the thermodynamically stable crystal phase. A simulated homogeneous nucleation rate of 5.0 × 1010 cm−3 s−1 was obtained for our system, which is in reasonable agreement with experimental and simulation rates for homogeneous nucleation of ice at similar degrees of supercooling. This study represents our first step in a series of studies aimed at understanding the nucleation and growth of crystals of organic salts near surfaces and inside nanopores

  11. Molecular simulation of homogeneous nucleation of crystals of an ionic liquid from the melt.

    Science.gov (United States)

    He, Xiaoxia; Shen, Yan; Hung, Francisco R; Santiso, Erik E

    2015-09-28

    The homogeneous nucleation of crystals of the ionic liquid [dmim(+)][Cl(-)] from its supercooled liquid phase in the bulk (P = 1 bar, T = 340 K, representing a supercooling of 58 K) was studied using molecular simulations. The string method in collective variables [Maragliano et al., J. Chem. Phys. 125, 024106 (2006)] was used in combination with Markovian milestoning with Voronoi tessellations [Maragliano et al., J. Chem. Theory Comput. 5, 2589-2594 (2009)] and order parameters for molecular crystals [E. E. Santiso and B. L. Trout, J. Chem. Phys. 134, 064109 (2011)] to sketch a minimum free energy path connecting the supercooled liquid and the monoclinic crystal phases, and to determine the free energy and the rates involved in the homogeneous nucleation process. The physical significance of the configurations found along this minimum free energy path is discussed with the help of calculations based on classical nucleation theory and with additional simulation results obtained for a larger system. Our results indicate that, at a supercooling of 58 K, the liquid has to overcome a free energy barrier of the order of 60 kcal/mol and to form a critical nucleus with an average size of about 3.6 nm, before it reaches the thermodynamically stable crystal phase. A simulated homogeneous nucleation rate of 5.0 × 10(10) cm(-3) s(-1) was obtained for our system, which is in reasonable agreement with experimental and simulation rates for homogeneous nucleation of ice at similar degrees of supercooling. This study represents our first step in a series of studies aimed at understanding the nucleation and growth of crystals of organic salts near surfaces and inside nanopores. PMID:26429023

  12. Molecular simulation of homogeneous nucleation of crystals of an ionic liquid from the melt

    Energy Technology Data Exchange (ETDEWEB)

    He, Xiaoxia; Shen, Yan [Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Hung, Francisco R., E-mail: frhung@lsu.edu [Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Center for Computation and Technology, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Santiso, Erik E. [Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States)

    2015-09-28

    The homogeneous nucleation of crystals of the ionic liquid [dmim{sup +}][Cl{sup −}] from its supercooled liquid phase in the bulk (P = 1 bar, T = 340 K, representing a supercooling of 58 K) was studied using molecular simulations. The string method in collective variables [Maragliano et al., J. Chem. Phys. 125, 024106 (2006)] was used in combination with Markovian milestoning with Voronoi tessellations [Maragliano et al., J. Chem. Theory Comput. 5, 2589–2594 (2009)] and order parameters for molecular crystals [E. E. Santiso and B. L. Trout, J. Chem. Phys. 134, 064109 (2011)] to sketch a minimum free energy path connecting the supercooled liquid and the monoclinic crystal phases, and to determine the free energy and the rates involved in the homogeneous nucleation process. The physical significance of the configurations found along this minimum free energy path is discussed with the help of calculations based on classical nucleation theory and with additional simulation results obtained for a larger system. Our results indicate that, at a supercooling of 58 K, the liquid has to overcome a free energy barrier of the order of 60 kcal/mol and to form a critical nucleus with an average size of about 3.6 nm, before it reaches the thermodynamically stable crystal phase. A simulated homogeneous nucleation rate of 5.0 × 10{sup 10} cm{sup −3} s{sup −1} was obtained for our system, which is in reasonable agreement with experimental and simulation rates for homogeneous nucleation of ice at similar degrees of supercooling. This study represents our first step in a series of studies aimed at understanding the nucleation and growth of crystals of organic salts near surfaces and inside nanopores.

  13. Design and development of single stage purification of papain using Ionic Liquid based aqueous two phase extraction system and its Partition coefficient studies

    Directory of Open Access Journals (Sweden)

    Senthilkumar Rathnasamy

    2013-04-01

    Full Text Available As an emerging trend in bioseparation, aqueous two phase extractions based on phosponium ionic liquid have been utilized in this work to extract papain from Carica papaya fruit latex and the same wascompared with conventional aqueous two phase extraction system. Factors affecting the partition coefficient of papain such as ionic liquid concentration, pH of the extraction system and temperature have been investigated. The optimization studies show that ionic liquid concentrations and pH are majorly influencing the phaseformations and papain partitioning. It reveals the importance of electrostatic and hydrophobic interactions in the papain partitioning. Purification studies performed on Gel Filtration Chromatography shows that 96% of the papain enzyme could be extracted with the phosponium based ionic liquid in a single stage extraction. The final fraction containing papain enzyme was confirmed by SDS Page analysis.

  14. Effect of electrolytes on surface tension and surface adsorption of 1-hexyl-3-methylimidazolium chloride ionic liquid in aqueous solution

    International Nuclear Information System (INIS)

    Surface and bulk properties of 1-hexyl-3-methylimidazolium chloride [C6mim][Cl] as an ionic liquid (IL) have been investigated by surface tension and electrical conductivity techniques at various temperatures. Results reveal that the ionic liquid behaves as surfactant-like and aggregates in aqueous solution. Critical aggregation concentration (cac) values obtained by conductivity and surface tension measurements are in good agreement with values found in the literature. A series of important and useful adsorption parameters including cac, surface excess concentration (Γ), and minimum surface area per molecule (Amin) at the air + water interface were estimated from surface tension in the presence and absence of different electrolytes. Obtained data show that the surface tension as well as the cac of [C6mim][Cl] is reduced by electrolytes. Also, values of surface excess concentration (Γ) show that the IL ions in the presence of electrolyte have much larger affinity to adsorption at the surface and this affinity increased in aqueous electrolyte solution in the order of I- > Br- > Cl- for counter ion of salts that was explained in terms of a larger repulsion of chloride anions from interface to the bromide and iodide anion as well as difference in their excess polarizability.

  15. Micellization and microstructural studies between amphiphilic drug ibuprofen with non-ionic surfactant in aqueous urea solution

    International Nuclear Information System (INIS)

    Highlights: • Micellization behavior of (ibuprofen + non-ionic surfactant) mixtures has been investigated. • Ion–dipole type of interaction between ibuprofen drug and non-ionic surfactant. • The negative β values propose attractive interactions between the components. • Stern–Volmer binding constants (Ksv) and dielectric constant of mixed systems have also been evaluated. • The results have applicability in drug delivery. - Abstract: Herein, we have accounted for the interaction between a non-steroidal anti-inflammatory drug ibuprofen (IBF) and non-ionic surfactant polyethoxyglycol t-octylphenyl ether (TX-100 (4-(1,1,3,3-tetramethylbutyl)phenyl-polyethylene glycol) and TX-114 ((1,1,3,3-tetramethylbutyl)phenyl-polyethylene glycol)), in aqueous urea solutions using tensiometric and fluorimetric techniques at T = 298.15 K. Surface tension measurements were carried out to evaluate the critical micelle concentrations (cmc) of the drug and surfactant as well as their mixtures of varying compositions. An increase in the surface charge of the micelles was observed with the addition of urea followed by halt of micelles formation. Various physicochemical parameters, such as, cmc values of the mixture, micellar mass fraction (X1Rub) of surfactants (TX-100/TX-114), interaction parameters (β) at the monolayer air–water interface and in bulk solutions, different thermodynamic parameters and activity coefficients (f1m,f2m) for the non-ionic surfactant and drug in the mixed micelles, were determined by using the approach of Clint, of Rubingh, and of Rosen. All results identified synergism and attractive interactions in the mixed systems of (drug–surfactant) mixtures and showed effective involvement of the non-ionic surfactant (TX-100/TX-114) component in the mixture. Micelle aggregation numbers (Nagg), evaluated by using steady-state fluorescence quenching studies, suggest that the contribution of non-ionic surfactant was always more than that of the drug

  16. Speciation of phytate ion in aqueous solution. Cadmium(II) interactions in aqueous NaCl at different ionic strengths

    Energy Technology Data Exchange (ETDEWEB)

    Stefano, Concetta de; Milea, Demetrio; Porcino, Nunziatina; Sammartano, Silvio [Universita di Messina, Dipartimento di Chimica Inorganica, Chimica Analitica e Chimica Fisica, Messina (Italy)

    2006-09-15

    Interactions between myo-inositol 1,2,3,4,5,6-hexakis(dihydrogen phosphate) (phytic acid) and cadmium(II) were studied by using potentiometry (at 25 C with the ISE-H{sup +} glass electrode) in different metal to ligand (Phy) ratios (1:1{<=}Cd{sup 2+}:Phy{<=}4:1) in NaCl{sub aq} at different ionic strengths (0.1{<=}I/mol L{sup -1}{<=}1). Nine Cd{sub i}H{sub j}Phy{sup (12-2i-j)-} species are formed with i=1 and 2 and 4{<=}j{<=}7; and trinuclear Cd{sub 3}H{sub 4}Phy{sup 2-}. Dependence of complex formation constants on ionic strength was modeled by using Specific ion Interaction Theory (SIT) equations. Phytate and cadmium speciation are also dependent on the metal to ligand ratio. Stability of Cd{sub i}H{sub j}Phy{sup (12-2i-j)-} species was modeled as a function of both the ligand protonation step (j) and the number of metal cations bound to phytate (i), and relationships found were used for the prediction of species other than those experimentally determined (mainly di- and tri-protonated complexes), allowing the possibility of modeling Phy and Cd(II) behavior in natural waters and biological fluids. A critical evaluation of phytate sequestering ability toward cadmium(II) has been made under several experimental conditions, and the determination of an empirical parameter has been proposed for an objective ''quantification'' of this ability. A thorough analysis of literature data on phytate-cadmium(II) complexes has been performed. (orig.)

  17. Characterization of electrochemically deposited films from aqueous and ionic liquid cobalt precursors toward hydrogen evolution reactions

    Science.gov (United States)

    Dushatinski, Thomas; Huff, Clay; Abdel-Fattah, Tarek M.

    2016-11-01

    Electrodepositions of cobalt films were achieved using an aqueous or an ethylene glycol based non-aqueous solution containing choline chloride (vitamin B4) with cobalt chloride hexahydrate precursor toward hydrogen evolution reactions from sodium borohydride (NaBH4) as solid hydrogen feedstock (SHF). The resulting cobalt films had reflectivity at 550 nm of 2.2% for aqueously deposited films (ACoF) and 1.3% for non-aqueously deposited films (NCoF). Surface morphology studied by scanning electron microscopy showed a positive correlation between particle size and thickness. The film thicknesses were tunable between >100 μm and <300 μm for each film. The roughness (Ra) value measurements by Dektak surface profiling showed that the NCoF (Ra = 165 nm) was smoother than the ACoF (Ra = 418 nm). The NCoFs and ACoFs contained only α phase (FCC) crystallites. The NCoFs were crystalline while the ACoFs were largely amorphous from X-ray diffraction analysis. The NCoF had an average Vickers hardness value of 84 MPa as compared to 176 MPa for ACoF. The aqueous precursor has a single absorption maximum at 510 nm and the non-aqueous precursor had three absorption maxima at 630, 670, and 695 nm. The hydrogen evolution reactions over a 1 cm2 catalytic surface with aqueous NaBH4 solutions generated rate constants (K) = equal to 4.9 × 10-3 min-1, 4.6 × 10-3 min-1, and 3.3 × 10-3 min-1 for ACoF, NCoF, and copper substrate respectively.

  18. Ionic interactions. Subnanoscale hydrophobic modulation of salt bridges in aqueous media.

    Science.gov (United States)

    Chen, Shuo; Itoh, Yoshimitsu; Masuda, Takuya; Shimizu, Seishi; Zhao, Jun; Ma, Jing; Nakamura, Shugo; Okuro, Kou; Noguchi, Hidenori; Uosaki, Kohei; Aida, Takuzo

    2015-05-01

    Polar interactions such as electrostatic forces and hydrogen bonds play an essential role in biological molecular recognition. On a protein surface, polar interactions occur mostly in a hydrophobic environment because nonpolar amino acid residues cover ~75% of the protein surface. We report that ionic interactions on a hydrophobic surface are modulated by their subnanoscale distance to the surface. We developed a series of ionic head groups-appended self-assembled monolayers with C2, C6, C8, and C12 space-filling alkyl chains, which capture a dendritic guest via the formation of multiple salt bridges. The guest release upon protonolysis is progressively suppressed when its distance from the background hydrophobe changes from 1.2 (C2) to 0.2 (C12) nanometers, with an increase in salt bridge strength of ~3.9 kilocalories per mole.

  19. Quantum Effects on the Free Energy of Ionic Aqueous Clusters Evaluated by Non-equilibrium Computational Methods

    CERN Document Server

    de la Peña, Lisandro Hernández

    2009-01-01

    Non-equilibrium simulation methods and rigid-body path-integral techniques are combined to estimate the relevance of protonic quantum effects in the free energy of ion-water clusters. Crooks' fluctuation relation is used to quantitatively characterize the impact of quantum effects on the dissociation free energy of the paradigm I^-(H_2O)_5. By employing a rigorous smoothing procedure in the calculation of the work distributions, the effects are found to be about 11% and therefore non negligible. Quantum effects on the potential of mean force of Na^+(H_2O)_{12} were also evaluated using Jarzynski's work theorem for a reaction coordinate, and they were also found to be significant. The results suggest that quantization should play a significant role in the kinetic of ionic transport in aqueous environments.

  20. Enhanced Stability of the Model Mini-protein in Amino Acid Ionic Liquids and Their Aqueous Solutions

    CERN Document Server

    Chevrot, Guillaume; Chaban, Vitaly V

    2015-01-01

    Using molecular dynamics simulations, the structure of model mini-protein was thoroughly characterized in the imidazolium-based amino acid ionic liquids and their aqueous solutions. We report that the mini-protein is more stable when AAIL is added as a cosolvent. Complete substitution of water by organic cations and anions further results in hindered conformational flexibility of the mini-protein. This observation suggests that AAILs are able to defend proteins from thermally induced denaturation. We show by means of radial distributions that the mini-protein is efficiently solvated by both solvents due to agood mutual miscibility. However, amino acid based anions prevail in the first coordination sphere of the mini-protein.

  1. Ionic Behavior in Highly Concentrated Aqueous Solutions Nanoconfined between Discretely Charged Silicon Surfaces.

    Science.gov (United States)

    Qiu, Yinghua; Ma, Jian; Chen, Yunfei

    2016-05-17

    Through molecular dynamics simulations considering thermal vibration of surface atoms, ionic behaviors in concentrated NaCl solutions confined between discretely charged silicon surfaces have been investigated. The electric double layer structure was found to be sensitive to the density and distribution of surface charges. Due to the discreteness of the surface charge, a slight charge inversion appeared which depended on the surface charge density, bulk concentration, and confinement. In the nanoconfined NaCl solutions concentrated from 0.2 to 4.0 M, the locations of accumulation layers for Na(+) and Cl(-) ions remained stable, but their peak values increased. The higher the concentration was, the more obvious the charge inversion appeared. In 4.0 M NaCl solution, Na(+) and Cl(-) ions show obvious alternating layered distributions which may correspond to the solidification found in experiments. By changing surface separation, the confinement had a large effect on the ionic distribution. As both surfaces approached each other, many ions and water molecules were squeezed out of the confined space. Two adjacent layers in ion or water distribution profiles can be forced closer to each other and merge together. From ionic hydration analysis, the coordination number of Na(+) ions in highly confined space was much lower than that in the bulk. PMID:27137990

  2. Trace element partitioning between aqueous fluids and silicate melts measured with a proton microprobe

    Energy Technology Data Exchange (ETDEWEB)

    Adam, J.; Green, T.H. [Macquarie Univ., North Ryde, NSW (Australia). School of Earth Sciences; Sie, S.H. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, NSW (Australia). Div. of Exploration Geoscience

    1996-12-31

    A series of experiments were performed to examine the capacity of H{sub 2}O-fluids to concentrate and transport incompatible elements through peridotitic mantle and metamorphosed (eclogitic) ocean crust. Two naturally occurring rock compositions, trondhjemitic and basanitic, were used in experiments. The proton microprobe was used to determine the trace element concentrations in the solutes from H{sub 2}O-fluids equilibrated at 900-1100 degree C, 2.0 GPa with water saturated melts of trondhjemitic and basanitic compositions. Partitioning data for H{sub 2}O-fluids and silicate melts show that H{sub 2}O-fluids equilibrated with mantle peridotites will not be strongly enriched in trace elements relative to their wallrocks, and thus they melts do not strongly concentrate alkaline earths Th and U, relative to high-field strength elements. 3 refs., 1 tab., 2 figs.

  3. EFFECTS OF NH4CI ON THE INTERACTION BETWEEN POLY(ETHYLENE OXIDE)AND IONIC SURFACTANTS IN AQUEOUS SOLUTIONS

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The interaction of poly(ethylene oxide)(PEO)with the ionic surfactants,sodium dodecylsulfate(SDS)and cetyltrimethylammonium chloride(CTAC)respectively,in aqueous solutions containing a certain concentration of NH4Cl,is studied by the viscosity measurement.It has been found that the ion-dipole interaction between PEO and ionic surfactants is changed considerably by the organic salt.For anionic surfactant of SDS,the addition of NH4Cl into solution strengthens the interaction between PEO and the headgroup of SDS.On the other hand,for cationic surfactant of CTAC,the interaction between PEO and the headgroup of CTAC is screened significantly by NH4Cl dissolved in solution.These findings may potentially be attributed to the negative property of the oxygen group of the PEO chain.In the presence of NH4Cl,the cationic ions of the organic salt bind to the oxygen group of the PEO chain so that PEO can be referred to as a pseudopolyelectrolyte in solution.

  4. Aggregation behavior and antimicrobial activity of ester-functionalized imidazolium- and pyridinium-based ionic liquids in aqueous solution.

    Science.gov (United States)

    Garcia, M Teresa; Ribosa, Isabel; Perez, Lourdes; Manresa, Angeles; Comelles, Francesc

    2013-02-26

    Two series of long chain imidazolium- and pyridinium-based ionic liquids containing an ester functional group in the alkyl side chain, 3-methyl-1-alkyloxycarbonylmethylimidazolium bromides (C(n)EMeImBr) and 1-alkyloxycarbonylmethylpyridinium bromides (C(n)EPyrBr), were synthesized and their thermal stability, aggregation behavior in aqueous medium, and antimicrobial activity investigated. The introduction of an ester group decreased the thermal stability of the functionalized ILs compared to simple alkyl chain containing ILs (1-alkyl-3-methylimidazolium bromides and 1-alkylpyridinium bromides). Tensiometry, conductimetry, and spectrofluorimetry were applied to study the self-aggregation of the amphiphilic ILs in aqueous solution. The ILs investigated displayed surface activity and the characteristic chain length dependence of the micellization process of surfactants. As compared to simple alkyl chain containing ILs bearing the same hydrocarbon chain, ester-functionalized ILs possess higher adsorption efficiency (pC(20)) and significantly lower critical micelle concentration (cmc) and surface tension at the cmc (γ(cmc)), indicating that the incorporation of an ester group promotes adsorption at the air/water interface and micelle formation. The antimicrobial activity was evaluated against Gram-negative and Gram-positive bacteria and fungi. ILs containing more than eight carbon atoms in the alkyl chain showed antimicrobial activity. Their efficiency as antimicrobial agents increased with the hydrophobicity of the amphiphilic cation being the C(12) homologous the most active compounds. The incorporation of an ester group particularly increased the biological activity against fungi.

  5. Formation and characteristics of aqueous two-phase systems formed by a cationic surfactant and a series of ionic liquids.

    Science.gov (United States)

    Wei, Xi-Lian; Wang, Xiu-Hong; Ping, A-Li; Du, Pan-Pan; Sun, De-Zhi; Zhang, Qing-Fu; Liu, Jie

    2013-11-15

    Aqueous two-phase systems (ATPS) were obtained in the aqueous mixtures of a cationic surfactant and a series of ionic liquids (ILs). The effects of IL structure, temperature and additives on the phase separation were systematically investigated. The microstructures of some ATPS were observed by freeze-fracture replication technique. Lyotropic liquid crystal was found in the bottom phase besides micelles under different conditions. Remarkably, both IL structure and additives profoundly affected the formation and properties of the ATPSs. The phase separation can be attributed to the existence of different aggregates and the cation-π interactions of the cationic surfactant with the ILs, which has a significant role in the formation of ATPS. The extraction capacity of the studied ATPS was also evaluated through their application in the extraction of two biosubstances. The results indicate that the ILs with BF4(-) as anion show much better extraction efficiencies than the corresponding ILs with Br(-) as anion do under the same conditions. l-Tryptophan was mainly distributed into the NPTAB-rich phase, while methylene blue and capsochrome were mainly in the IL-rich phase.

  6. Removal of anionic azo dyes from aqueous solution by functional ionic liquid cross-linked polymer

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Hejun [Key Laboratory of Colloid and Interface Chemistry, Shandong University, Ministry of Education, Jinan 250100 (China); Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province, China West Normal University, Nanchong 637000 (China); Kan, Taotao [CNOOC Energy Technology and Services-oilfield Technology Services Co., Tanggu, Tianjin 300452 (China); Zhao, Siyuan; Qian, Yixia; Cheng, Xiyuan; Wu, Wenli [School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Wang, Xiaodong [Shandong Provincial Analysis and Test Center, Jinan 250100 (China); Zheng, Liqiang, E-mail: lqzheng@sdu.edu.cn [Key Laboratory of Colloid and Interface Chemistry, Shandong University, Ministry of Education, Jinan 250100 (China)

    2013-10-15

    Highlights: • Equilibrium, kinetic and thermodynamic of adsorption of dyes onto PDVB-IL was investigated. • PDVB-IL has a high adsorption capacity to treat dyes solution. • Higher adsorption capacity is due to the functional groups of PDVB-IL. • Molecular structure of dyes influences the adsorption capacity. -- Abstract: A novel functional ionic liquid based cross-linked polymer (PDVB-IL) was synthesized from 1-aminoethyl-3-vinylimidazolium chloride and divinylbenzene for use as an adsorbent. The physicochemical properties of PDVB-IL were investigated by Fourier transform infrared spectroscopy, scanning electron microscopy and thermogravimetric analysis. The adsorptive capacity was investigated using anionic azo dyes of orange II, sunset yellow FCF, and amaranth as adsorbates. The maximum adsorption capacity could reach 925.09, 734.62, and 547.17 mg/g for orange II, sunset yellow FCF and amaranth at 25 °C, respectively, which are much better than most of the other adsorbents reported earlier. The effect of pH value was investigated in the range of 1–8. The result shows that a low pH value is found to favor the adsorption of those anionic azo dyes. The adsorption kinetics and isotherms are well fitted by a pseudo second-order model and Langmuir model, respectively. The adsorption process is found to be dominated by physisorption. The introduction of functional ionic liquid moieties into cross-linked poly(divinylbenzene) polymer constitutes a new and efficient kind of adsorbent.

  7. Removal of anionic azo dyes from aqueous solution by functional ionic liquid cross-linked polymer

    International Nuclear Information System (INIS)

    Highlights: • Equilibrium, kinetic and thermodynamic of adsorption of dyes onto PDVB-IL was investigated. • PDVB-IL has a high adsorption capacity to treat dyes solution. • Higher adsorption capacity is due to the functional groups of PDVB-IL. • Molecular structure of dyes influences the adsorption capacity. -- Abstract: A novel functional ionic liquid based cross-linked polymer (PDVB-IL) was synthesized from 1-aminoethyl-3-vinylimidazolium chloride and divinylbenzene for use as an adsorbent. The physicochemical properties of PDVB-IL were investigated by Fourier transform infrared spectroscopy, scanning electron microscopy and thermogravimetric analysis. The adsorptive capacity was investigated using anionic azo dyes of orange II, sunset yellow FCF, and amaranth as adsorbates. The maximum adsorption capacity could reach 925.09, 734.62, and 547.17 mg/g for orange II, sunset yellow FCF and amaranth at 25 °C, respectively, which are much better than most of the other adsorbents reported earlier. The effect of pH value was investigated in the range of 1–8. The result shows that a low pH value is found to favor the adsorption of those anionic azo dyes. The adsorption kinetics and isotherms are well fitted by a pseudo second-order model and Langmuir model, respectively. The adsorption process is found to be dominated by physisorption. The introduction of functional ionic liquid moieties into cross-linked poly(divinylbenzene) polymer constitutes a new and efficient kind of adsorbent

  8. Ionic Liquid Surfactant Mediated Structural Transitions and Self-Assembly of Bovine Serum Albumin in Aqueous Media: Effect of Functionalization of Ionic Liquid Surfactants.

    Science.gov (United States)

    Singh, Gurbir; Kang, Tejwant Singh

    2015-08-20

    The self-assembly of globular protein bovine serum albumin (BSA) has been investigated in aqueous solutions of ionic liquid surfactants (ILSs), 1-dodecyl-3-methyl imidazolium chloride, [C12mim][Cl], and its amide, [C12Amim][Cl], and ester, [C12Emim][Cl], functionalized counterparts. Dynamic light scattering (DLS) has provided insights into the alterations in hydrodynamic radii (D(h)) of BSA as a function of concentration of ILSs establishing the presence of different types of BSA-ILS complexes in different concentration regimes of ILSs. Isothermal titration calorimetry (ITC) has been exploited to quantify the ILSs interacting with BSA in dilute concentration regime of ILSs. The zeta-potential measurements shed light on changes in the charged state of BSA. The morphology of various self-assembled structures of BSA in different concentration regimes of ILSs have been explored using confocal laser scanning microscopy (CLSM) and scanning electron microscopy. The structural variations in ILSs have been found to produce remarkable effect on the nature and morphology of self-assembled structures of BSA. The presence of nonfunctionalized [C12mim][Cl] IL at all investigated concentrations has led to the formation of unordered large self-assembled structures of BSA. On the other hand, in specific concentration regimes, ordered self-assembled structures such as long rods and right-handedly twisted helical amyloid fibers have been observed in the presence of functionalized [C12Amim][Cl] and [C12Emim][Cl] ILSs, respectively. The nature of the formed helical fibers as amyloid ones has been confirmed using FTIR spectroscopy. Steady-state fluorescence and circular dichroism (CD) spectroscopy have provided insights into folding and unfolding of BSA as fashioned by interactions with ILSs in different concentration regimes supporting the observations made from other studies.

  9. Molecular dynamics simulations of the aqueous interface with the [BMI][PF6] ionic liquid: Comparison of different solvent models.

    Science.gov (United States)

    Chevrot, G; Schurhammer, R; Wipff, G

    2006-09-28

    We report a Molecular Dynamics (MD) study of the interface between water and the hygroscopic room temperature Ionic Liquid "IL" [BMI][PF6] (1-butyl-3-methyl-imidazolium hexafluorophosphate), comparing the TIP3P, SPC/E and TIP5P models for water and two IL models where the ions are +/-1 or +/-0.9 charged. A recent MD study (A. Chaumont, R. Schurhammer and G. Wipff, J. Phys. Chem. B, 2005, 109, 18964) showed that using TIP3P water in conjunction with the IL(+/-1) model led to water-IL mixing without forming an interface, whereas a biphasic system could be obtained with the IL(+/-0.9) model. With the TIP5P and SPC/E models, the juxtaposed aqueous and IL phases are found to remain distinct for at least 20 ns. The resulting IL humidity, exaggerated with the IL(+/-1) model, is in better agreement with experiment using the IL(+/-0.9) model. We also report demixing simulations on the "randomly mixed" liquids, using the IL(+/-0.9) model for the ionic liquid. With the three tested water models, the phases separate very slowly ( approximately 20 ns or more) compared to "classical" chloroform-water mixtures (less than 1 ns), leading to biphasic systems similar to those obtained after equilibration of the juxtaposed liquids. The characteristics of the interface (size, polarity, ion orientation, electrostatic potential) are compared with the different models. Possible reasons why, among the three tested water models, the widely-used TIP3P model exaggerates the inter-solvent mixing, are analyzed. The difficulty in computationally and experimentally equilibrating water-IL mixtures is attributed to the slow dynamics and micro-heterogeneity of the IL and to the different states of water in the IL phase.

  10. NMR investigation of imidazolium-based ionic liquids and their aqueous mixtures.

    Science.gov (United States)

    Cesare Marincola, Flaminia; Piras, Cristina; Russina, Olga; Gontrani, Lorenzo; Saba, Giuseppe; Lai, Adolfo

    2012-04-10

    (1)H and (13)C NMR spectroscopy is employed to investigate the interaction of water with two imidazolium-based ionic liquids (ILs), 1-hexyl-3-methylimidazolium bromide ([C(6)mim]Br) and 1-octyl-3-methylimidazolium bromide ([C(8)mim]Br), at IL concentrations well above the critical aggregation concentration (CAC). The results are compared with those of the neat samples. To this aim, a detailed analysis of the changes in the (1)H chemical shifts, (13)C relaxation parameters, and 2D ROESY data due to the presence of water is performed. The results for both neat ILs are consistent with a packed structure where head-to-head, head-to-tail, and tail-to-tail contacts occur and where the site of maximal mobility restriction is at the polar head. At the lowest investigated water content, the presence of water influences mainly the environment around the IL polar head, slowing down the motional dynamics of the aromatic ring with respect to the alkyl chain. At higher water contents this difference diminishes, the motional freedom of the whole molecule increasing. The presence of ROESY cross-peaks between protons in the polar and apolar IL regions, as well as between protons in non-neighboring alkyl groups, at all investigated water contents suggests that the alkyl tails are not fully segregated in hydrophobic domains, as expected for micelle-like structures.

  11. Aqueous Self-Assembly of Non-Ionic Bottlebrush Block Copolymer Surfactants with Tunable Molecular Shapes

    Science.gov (United States)

    Rzayev, Javid

    2015-03-01

    Polymer amphiphiles provide a robust and versatile platform for the fabrication of nanostructured soft matter. In this research, we explore a new class of polymer surfactants based on comb-like bottlebrush architecture as highly tunable molecular building blocks for aqueous self-assembly. Excluded volume interactions between densely grafted polymer side chains in the bottlebrush architecture are alleviated by backbone stretching, which leads to the formation of shape-persistent cylindrical macromolecules whose molecular dimensions can be precisely tailored during chemical synthesis. Amphiphilic bottlebrush block copolymers containing hydrophobic polylactide (PLA) and hydrophilic poly(oligoethylene oxide methacrylate) (PEO) side chains of various lengths were synthesized by a combination of controlled radical and ring-opening polymerizations. In dilute aqueous solutions, bottlebrush surfactants rapidly assembled into spherical, cylindrical and bilayer aggregates, as visualized by cryogenic transmission electron microscopy (cryo-TEM). Depending on the compositional side chain asymmetry, the formation of spherical micelles with different sizes and dispersities was observed. The molecular shape-dependent assembly was analyzed with help of a packing parameter (p) computed from the molecular composition data akin to small molecule surfactants, with most uniform spherical aggregates observed for bottlebrush amphiphiles with p close to 0.3. The formation of highly uniform micelles and the presence of a rich morphological diagram with relatively narrow compositional windows were attributed to the lack of conformational freedom in bottlebrush surfactants. Similarly, the unusual formation of cylindrical micelles with long aspect ratios for such high molecular weight amphiphiles was attributed to their inability to stabilize morphological defects, such as Y-junctions, with large deviations from mean curvature. Financial support for this work was provided by the National

  12. Thermophysical properties of aqueous solution of ammonium-based ionic liquids.

    Science.gov (United States)

    Umapathi, Reddicherla; Attri, Pankaj; Venkatesu, Pannuru

    2014-06-01

    Experimental densities (ρ), ultrasonic sound velocities (u), viscosities (η), and refractive indices (n(D)) of binary mixtures of ammonium-based ionic liquids (ILs) such as diethylammonium acetate (DEAA) [(CH3CH2)2NH][CH3COO], triethylammonium acetate (TEAA) [(CH3CH2)3NH][CH3COO], diethylammonium hydrogen sulfate (DEAS) [(CH3CH2)2NH][HSO4], triethylammonium hydrogen sulfate (TEAS) [(CH3CH2)3NH][HSO4], trimethylammonium acetate (TMAA) [(CH3)3NH][CH3COO], and trimethylammonium hydrogen sulfate (TMAS) [(CH3)3NH][HSO4] with water are reported over the wide composition range at 25 °C under atmospheric pressure. The excess molar volumes (V(E)), deviation in isentropic compressibilities (Δκ(s)), deviation in viscosities (Δη) and deviation in refractive indices (Δn(D)) are calculated from experimental values and are correlated by Redlich-Kister polynomial equations. The V(E) and Δκ(s) values for the aforesaid systems are negative over the entire composition range while the Δη and Δn(D) values are positive under the same experimental conditions. The intermolecular interactions and structural effects were analyzed on the basis of measured and derived properties. A qualitative analysis of the results is discussed in terms of the ion-dipole, ion-pair interactions and hydrogen bonding between ILs and water. Furthermore, the hydrogen bonding features between ILs with water were analyzed by using a molecular modeling program with the help of HyperChem7. PMID:24830564

  13. Impact of ionic liquids in aqueous solution on bacterial plasma membranes studied with molecular dynamics simulations.

    Science.gov (United States)

    Lim, Geraldine S; Zidar, Jernej; Cheong, Daniel W; Jaenicke, Stephan; Klähn, Marco

    2014-09-01

    The impact of five different imidazolium-based ionic liquids (ILs) diluted in water on the properties of a bacterial plasma membrane is investigated using molecular dynamics (MD) simulations. Cations considered are 1-octyl-3-methylimidazolium (OMIM), 1-octyloxymethyl-3-methylimidazolium (OXMIM), and 1-tetradecyl-3-methylimidazolium (TDMIM), as well as the anions chloride and lactate. The atomistic model of the membrane bilayer is designed to reproduce the lipid composition of the plasma membrane of Gram-negative Escherichia coli. Spontaneous insertion of cations into the membrane is observed in all ILs. Substantially more insertions of OMIM than of OXMIM occur and the presence of chloride reduces cation insertions compared to lactate. In contrast, anions do not adsorb onto the membrane surface nor diffuse into the bilayer. Once inserted, cations are oriented in parallel to membrane lipids with cation alkyl tails embedded into the hydrophobic membrane core, while the imidazolium-ring remains mostly exposed to the solvent. Such inserted cations are strongly associated with one to two phospholipids in the membrane. The overall order of lipids decreased after OMIM and OXMIM insertions, while on the contrary the order of lipids in the vicinity of TDMIM increased. The short alkyl tails of OMIM and OXMIM generate voids in the bilayer that are filled by curling lipids. This cation induced lipid disorder also reduces the average membrane thickness. This effect is not observed after TDMIM insertions due to the similar length of cation alkyl chain and the fatty acids of the lipids. This lipid-mimicking behavior of inserted TDMIM indicates a high membrane affinity of this cation that could lead to an enhanced accumulation of cations in the membrane over time. Overall, the simulations reveal how cations are inserted into the bacterial membrane and how such insertions change its properties. Moreover, the different roles of cations and anions are highlighted and the fundamental

  14. Degradation of imidazolium-based ionic liquids in aqueous solution using plasma electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Gao, J.; Chen, L.; He, Y.Y.; Yan, Z.C., E-mail: zcyan@scut.edu.cn; Zheng, X.J.

    2014-01-30

    Highlights: • More than 95% of imidazolium-based ILs was degraded within 120 min by means of PE. • The removal efficiency decreased as the order [Cl]{sup −} > [Br]{sup −} > [Ac]{sup −} ≈ [BF{sub 4}]{sup −}. • [C{sub 2}mim]Cl was the most stable compared to [C{sub 4}mim]Cl and [C{sub 6}mim]Cl. • The initial concentration of ILs was found to affect the degradation efficiency. • The imidazole ring was oxidized and then broken to form small molecular compounds. -- Abstract: A novel method of degrading imidazolium-based ionic liquids (ILs) in wastewater using plasma electrolysis (PE) was proposed. The advantage of the PE method was that the ILs acted as both pollutant and electrolyte in the system. Results indicated that ILs with initial concentrations of 1.0–4.0 g/100 mL readily decomposed under an applied voltage of 600 V within 120 min. The anion and alkyl chain lengths of the ILs, discharge time, and post-treatment time were also found to be significant, and the degradation could be described by pseudo-first-order kinetics. Moreover, the energy efficiency of PE for degradation was calculated. The energy yield was generally higher than 2.0 g/kWh, which is approximately 100 times that of the degradation of methyl orange. The oxygen atom, hydroxyl radicals, and hydrogen peroxide produced by PE were important in the oxidation and cleavage of the ILs, and the degradation pathway of the imidazolium-based ILs was investigated using IC, FT-IR, NMR, and GC–MS techniques.

  15. Improving the extraction and purification of immunoglobulin G by the use of ionic liquids as adjuvants in aqueous biphasic systems.

    Science.gov (United States)

    Ferreira, Ana M; Faustino, Vânia F M; Mondal, Dibyendu; Coutinho, João A P; Freire, Mara G

    2016-10-20

    Immunoglobulins G (IgG) could become widespread biopharmaceuticals if cost-efficient processes for their extraction and purification are available. In this work, aqueous biphasic systems (ABS) composed of polyethylene glycols and a buffered salt, and with ionic liquids (ILs) as adjuvants, have been studied as alternative extraction and purification platforms of IgG from a rabbit serum source. Eleven ILs were investigated to provide insights on the chemical features which maximize the IgG partitioning. It is shown that in polymer-salt systems pure IgG preferentially partitions to the polymer-rich phase; yet, the complete extraction was never attained. Remarkably, after the addition of 5wt% of adequate ILs to polymer-salt ABS, the complete extraction of pure IgG in a single-step was accomplished. The best systems and conditions were then applied to the extraction and purification of IgG directly from rabbit serum samples. The complete extraction of IgG in a single-step was maintained while its purity in the polymer-rich phase was enhanced by ca. 37% as compared to the IL-free ABS. The antibody stability was also evaluated revealing that appropriate ILs are able to maintain the IgG stability and can be used as phase-forming components of ABS when envisaging the purification of high-cost biopharmaceuticals.

  16. Aggregation behavior of 1-dodecyl-3-methylimidazolium bromide in aqueous solution: effect of ionic liquids with aromatic anions.

    Science.gov (United States)

    Gu, Yingqiu; Shi, Lijuan; Cheng, Xiyuan; Lu, Fei; Zheng, Liqiang

    2013-05-28

    The effects of ionic liquids (ILs), 1-butyl-3-methylimidazolium methylsulfonate (bmimMsa), 1-butyl-3-methylimidazolium benzenesulfonate (bmimBsa), and 1-butyl-3-methylimidazolium 2-naphthalenesulfonate (bmimNsa), on the aggregation behavior of 1-dodecyl-3-methylimidazolium bromide (C12mimBr) in aqueous solution were investigated by surface tension, dynamic light scattering measurements, and (1)H NMR spectroscopy. The ability to promote the surfactant aggregation is in the order bmimNsa > bmimBsa > bmimMsa. Nevertheless, only bmimNsa distinctly reduces both the CMC value and the surface tension at CMC. Due to the penetration of C10H7SO3(-)anions into the surfactant aggregate, bmimNsa is found to induce a phase transition from micelles to vesicles, whereas the other ILs only slightly increase the sizes of micelles. The combined effect of intermolecular interactions, such as hydrophobic effect, electrostatic attractions, and π-π stacking interactions, is supposed to be responsible for this structural transformation, in which π-π stacking plays an important role. PMID:23642150

  17. Extraction, Preconcentration and Isolation of Flavonoids from Apocynum venetum L. Leaves Using Ionic Liquid-Based Ultrasonic-Assisted Extraction Coupled with an Aqueous Biphasic System

    OpenAIRE

    Zhijian Tan; Yongjian Yi; Hongying Wang; Wanlai Zhou; Chaoyun Wang

    2016-01-01

    Background: Ionic liquids (ILs) are considered as green solvents, and widely applied for the extraction of various compounds. Methods: The present research focuses on the extraction of flavonoids from Apocynum venetum L. leaves by ultrasound-assisted extraction (UAE). Several major influencing factors were optimized. Then, an aqueous biphasic system (ABS) was applied for further isolation of flavonoids. Results: The flavonoids were mainly distributed in the top phase, while impurities were ex...

  18. Recovery of Scandium(III) from Aqueous Solutions by Solvent Extraction with the Functionalized Ionic Liquid Betainium Bis(trifluoromethylsulfonyl)imide

    OpenAIRE

    Onghena, Bieke; Binnemans, Koen

    2015-01-01

    The ionic liquid betainium is(trifluoromethylsulfonyl)imide [Hbet][Tf2N] was used for the extraction of scandium from aqueous solutions. The influence of several extraction parameters on the extraction efficiency was investigated, including the initial metal concentration, phase ratio, and pH. The extraction kinetics was examined, and a comparison was made between conventional liquid−liquid extraction and homogeneous liquid−liquid extraction (HLLE). The stoichiometry of the extracted scandium...

  19. Transport properties investigation of aqueous protic ionic liquid solutions through conductivity, viscosity, and NMR self-diffusion measurements.

    Science.gov (United States)

    Anouti, Mérièm; Jacquemin, Johan; Porion, Patrice

    2012-04-12

    We present a study on the transport properties through conductivity (σ), viscosity (η), and self-diffusion coefficient (D) measurements of two pure protic ionic liquids--pyrrolidinium hydrogen sulfate, [Pyrr][HSO(4)], and pyrrolidinium trifluoroacetate, [Pyrr][CF(3)COO]--and their mixtures with water over the whole composition range at 298.15 K and atmospheric pressure. Based on these experimental results, transport mobilities of ions have been then investigated in each case through the Stokes-Einstein equation. From this, the proton conduction in these PILs follows a combination of Grotthuss and vehicle-type mechanisms, which depends also on the water composition in solution. In each case, the displacement of the NMR peak attributed to the labile proton on the pyrrolidinium cation with the PILs concentration in aqueous solution indicates that this proton is located between the cation and the anion for a water weight fraction lower than 8%. In other words, for such compositions, it appears that this labile proton is not solvated by water molecules. However, for higher water content, the labile protons are in solution as H(3)O(+). This water weight fraction appears to be the solvation limit of the H(+) ions by water molecules in these two PILs solutions. However, [Pyrr][HSO(4)] and [Pyrr][CF(3)COO] PILs present opposed comportment in aqueous solution. In the case of [Pyrr][CF(3)COO], η, σ, D, and the attractive potential, E(pot), between ions indicate clearly that the diffusion of each ion is similar. In other words, these ions are tightly bound together as ion pairs, reflecting in fact the importance of the hydrophobicity of the trifluoroacetate anion, whereas, in the case of the [Pyrr][HSO(4)], the strong H-bond between the HSO(4)(-) anion and water promotes a drastic change in the viscosity of the aqueous solution, as well as on the conductivity which is up to 187 mS·cm(-1) for water weight fraction close to 60% at 298 K.

  20. Investigation of the Ionic Hydration in Aqueous Salt Solutions by Soft X-ray Emission Spectroscopy.

    Science.gov (United States)

    Jeyachandran, Y L; Meyer, F; Benkert, A; Bär, M; Blum, M; Yang, W; Reinert, F; Heske, C; Weinhardt, L; Zharnikov, M

    2016-08-11

    Understanding the molecular structure of the hydration shells and their impact on the hydrogen bond (HB) network of water in aqueous salt solutions is a fundamentally important and technically relevant question. In the present work, such hydration effects were studied for a series of representative salt solutions (NaCl, KCl, CaCl2, MgCl2, and KBr) by soft X-ray emission spectroscopy (XES) and resonant inelastic soft X-ray scattering (RIXS). The oxygen K-edge XES spectra could be described with three components, attributed to initial state HB configurations in pure water, water molecules that have undergone an ultrafast dissociation initiated by the X-ray excitation, and water molecules in contact with salt ions. The behavior of the individual components, as well as the spectral shape of the latter component, has been analyzed in detail. In view of the role of ions in such effects as protein denaturation (i.e., the Hofmeister series), we discuss the ion-specific nature of the hydration shells and find that the results point to a predominant role of anions as compared to cations. Furthermore, we observe a concentration-dependent suppression of ultrafast dissociation in all salt solutions, associated with a significant distortion of intact HB configurations of water molecules facilitating such a dissociation. PMID:27442708

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

    Science.gov (United States)

    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.

  2. The assessment of removing strontium and cesium cations from aqueous solutions based on the combined methods of ionic liquid extraction and electrodeposition

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Po-Yu [Faculty of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung City 807, Taiwan (China)]. E-mail: pyc@kmu.edu.tw

    2007-05-05

    The extraction of Sr{sup 2+} and Cs{sup +} from aqueous solutions by using the ionophores dicyclohexano-18-crown-6 (DCH18C6) and calix[4]arene-bis(tert-octylbenzo-crown-6) (BOBCalixC6), respectively, was demonstrated in the hydrophobic, room-temperature ionic liquid (RTIL), tri-1-butylmethylammonium bis((trifluoromethyl)sulfonyl)imide (Bu{sub 3}MeN-TFSI). The water contents of several hydrophobic ionic liquids and the absorption/desorption reversibility of oxygen and moisture in the Bu{sub 3}MeN-TFSI ionic liquid were determined by electrochemical techniques. The relationship between the distribution coefficient, D{sub M}, and the concentration ratios of C{sub ionophore,IL}/C{sub metal{sub ion,aq}} were investigated. The values of D {sub M} increase with increasing the concentration ratios and they are also influenced with the counter ions of Sr{sup 2+} and Cs{sup +} in the aqueous solutions. In the previous study, it was demonstrated that the Sr{sup 2+} and Cs{sup +} cations in the Bu{sub 3}MeN-TFSI ionic liquid could be coordinated by DCH18C6 and BOBCalixC6, respectively, and formed the DCH18C6.Sr{sup 2+} and BOBCalixC6.2Cs{sup +} ions, which would be cathodically reduced to Sr- and Cs-amalgam at a mercury film electrode (MFE). In this study, the probability was evaluated if the Sr{sup 2+} and Cs{sup +} cations extracted from the aqueous solutions can be really reduced to respective amalgam.

  3. NMR, surface tension and conductance study to investigate host-guest inclusion complexes of three sequential ionic liquids with β-cyclodextrin in aqueous media

    Science.gov (United States)

    Barman, Siti; Ekka, Deepak; Saha, Subhadeep; Roy, Mahendra Nath

    2016-08-01

    Host-guest inclusion complexes of three sequential cationic room temperature surface active ionic liquids, benzyltrialkylammonium chloride [(C6H5CH2)N(CnH2n+1)3Cl; where n = 1, 2, 4] with β-cyclodextrin in aqueous media have been studied using surface tension, conductance and NMR spectroscopy. All the studies have suggested that the hydrophobic benzyl group of ionic liquids is encapsulated inside into the cavity of β-cyclodextrin and played a crucial role in supporting the formation of inclusion complexes. The variation of the thermodynamic parameters with guest size, shape is used to draw inferences about contributions to the overall binding by means of the driving forces, viz., hydrophobic effect, steric hindrance, van der Waal force, and electrostatic force.

  4. Effect of alkyl chain length and temperature on the thermodynamic properties of ionic liquids 1-alkyl-3-methylimidazolium bromide in aqueous and non-aqueous solutions at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghi, Rahmat [Department of Chemistry, University of Kurdistan, Sanandaj (Iran, Islamic Republic of)], E-mail: rahsadeghi@yahoo.com; Shekaari, Hemayat [Department of Chemistry, Faculty of Science, University of Mohaghegh Ardabili, Ardabil (Iran, Islamic Republic of); Hosseini, Rahim [Department of Chemistry, University of Kurdistan, Sanandaj (Iran, Islamic Republic of)

    2009-02-15

    The alkyl chain length of 1-alkyl-3-methylimidazolium bromide ([Rmim][Br], R = propyl (C{sub 3}), hexyl (C{sub 6}), heptyl (C{sub 7}), and octyl (C{sub 8})) was varied to prepare a series of room-temperature ionic liquids (RTILs), and experimental measurements of density and speed of sound at different temperatures ranging from (288.15 to 308.15) K for their aqueous and methanolic solutions in the dilute concentration region (0.01 to 0.30) mol . kg{sup -1} were taken. The values of the compressibilities, expansivity and apparent molar properties for [C{sub n}mim][Br] in aqueous and methanolic solutions were determined at the investigated temperatures. The obtained apparent molar volumes and apparent molar isentropic compressibilities were fitted to the Redlich-Mayer and the Pitzer's equations from which the corresponding infinite dilution molar properties were obtained. The values of the infinite dilution molar properties were used to obtain some information about solute-solvent and solute-solute interactions. The thermodynamic properties of investigated ionic liquids in aqueous solutions have been compared with those in methanolic solutions. Also, the comparison between thermodynamic properties of investigated solutions and those of electrolyte solutions, polymer solutions, cationic surfactant solutions and tetraalkylammonium salt solutions have been made.

  5. Separation of curcuminoids using ionic liquid based aqueous two-phase system coupled with in situ dispersive liquid-liquid microextraction.

    Science.gov (United States)

    Shu, Yang; Gao, Mingcen; Wang, Xueying; Song, Rusheng; Lu, Jun; Chen, Xuwei

    2016-01-01

    An aqueous two-phase extraction system (ATPS) combined with an in situ dispersive liquid-liquid microextraction (DLLME) method using imidazolium ionic liquids (ILs) for the separation of curcuminoids is developed. The influence of structure of IL, the type of metathesis reagents, and the back extraction agents on the extraction efficiency is investigated. 2.0mg of curcuminoids are extracted by an IL ATPS composed of 0.4g 1,3-diethylimidazolium iodine (EeimI), 0.6g potassium hydrogen phosphate, 1.0g water. Then the bis[(trifluoromethyl)sulfonyl]imide lithium (LiNTf2) aqueous solution is added to the EeimI-rich phase of the ATPS. The water-immiscible ionic liquids, 1,3-diethylimidazole bis[(trifluoromethyl)sulfonyl]imide (EeimNTf2), forms by the metathesis reaction. The in situ DLLME is triggered simultaneously and further purifies the curcuminoids. 92% of EeimI transforms into EeimNTf2 and thus the Eeim(+) cation is used for twice in this method. Finally, 0.1mol/L NaOH aqueous solution is used as the back extraction reagent. The curcuminoids precipitate is achieved with 93% of recovery when the aqueous solution is adjusted to pH 3.0. This ATPS-DLLME method is successfully applied to the separation of curcuminoids from Curcuma Longa (0.96±0.02% of extraction yield, a purity of >51% with respect to the total dry mass of the product).

  6. Liquid-liquid miscibility and volumetric properties of aqueous solutions of ionic liquids as a function of temperature

    OpenAIRE

    Wang, Silu; Johan JACQUEMIN; Husson, Pascale; Hardacre, Christpher; Costa Gomes, Margarita F.

    2009-01-01

    The volumetric properties of seven {water + ionic liquid} binary mixtures have been studied as a function of temperature from (293 to 343) K. The phase behaviour of the systems was first investigated using a nephelometric method and excess molar volumes were calculated from densities measured using an Anton Paar densimeter and fitted using a Redlich-Kister type equation. Two ionic liquids fully miscible with water (1-butyl-3-methylimidazolium tetrafluoroborate ([CCIm][BF]) and 1-ethyl-3-methy...

  7. Potentiometric and spectrophotometric characterization of the UO22+-citrate complexes in aqueous solution, at different concentrations, ionic strengths and supporting electrolytes

    International Nuclear Information System (INIS)

    In this paper we report an investigation on the interactions between dioxouranium(VI) and citrate using potentiometry (H+-glass electrode) and UV-spectrophotometry. Potentiometric measurements were carried out in NaCl and KNO3 aqueous solutions at t = 25 C in a wide range of experimental conditions (concentrations, ligand/metal molar ratio, pH, titrants). Measurements in NaCl were carried out at different ionic strength values (0.1 ≤ I/mol L-1 ≤ 1.0); different procedures were employed for the acquisition of experimental data and careful analysis of these data performed. In all cases the speciation model that best fits experimental data takes into account the formation of the following species: UO2(Cit)-, (UO2)2(Cit)22-, (UO2)2(Cit)2(OH)24-, (UO2)2(Cit)2(OH)3-, (UO2)2(Cit)(OH)2-, (UO2)2(Cit)(OH)0, (UO2)3(Cit)2(OH)55-. The dependence on ionic strength of formation constants was taken into account by using both a simple Debye-Hueckel type equation and the SIT (specific ion interaction theory) approach. Moreover, a visible absorption spectrum for each complex reaching a significant percentage of formation in solution (KNO3 medium) has been calculated to characterise the compounds found by pH-metric refinement. Recommended values for the uranyl-citrate species were proposed for each ionic strength values in NaCl aqueous solution. Comparison with literature stability constants is reported too. (orig.)

  8. Ionic Liquid-salt Aqueous Two-phase System, a Novel System for the Extraction of Abused Drugs

    Institute of Scientific and Technical Information of China (English)

    She Hong LI; Chi Yang HE; Hu Wei LIU; Ke An LI; Feng LIU

    2005-01-01

    A 1-butyl-3-methylimidazolium chloride-salt aqueous two-phase system was studied on extraction of abused drugs. The effects of sorts of salts, temperature, concentration of salt and drugs on system were investigated systematically. A satisfactory extraction efficiency of 93%was obtained for papaverine while that of morphine was 65%. The extraction mechanism was primarily discussed.

  9. Concentration and temperature induced dual-responsive wormlike micelle to hydrogel transition in ionic liquid-type surfactant [C₁₆imC₉]Br aqueous solution without additives.

    Science.gov (United States)

    Hu, Yimin; Ge, Lingling; Han, Jie; Guo, Rong

    2015-07-28

    A highly viscoelastic fluid formed by the ionic liquid-type surfactant 1-hexadecyl-3-nonyl imidazolium bromide ([C16imC9]Br) in water in the absence of any additive was studied. The phase behavior and morphology of aggregates were studied by a combination of rheological techniques, small-angle X-ray scattering (SAXS), cryo-etch-scanning electron microscopy (cryo-etch-SEM) and freeze-fractured transmission electron microscopy (FF-TEM). [C16imC9]Br aqueous solutions showed interesting rheological behavior as a function of both concentration and temperature, which invoked a transition between wormlike micelles and hydrogels. With the increase in [C16imC9]Br concentration, the aqueous solution could form viscoelastic wormlike micelles (50-80 mM), hydrogels (90-110 mM) and wormlike micelles (120-180 mM). As the temperature increased, the hydrogels (90-110 mM) could also transit to wormlike micelles. The unusual phase transition between wormlike micelles and elastic hydrogels was postulated to be the change of the average micellar length. PMID:26059909

  10. Al-Co Alloys Prepared by Vacuum Arc Melting: Correlating Microstructure Evolution and Aqueous Corrosion Behavior with Co Content

    OpenAIRE

    Angeliki Lekatou; Athanasios K. Sfikas; Christina Petsa; Alexandros E. Karantzalis

    2016-01-01

    Hypereutectic Al-Co alloys of various Co contents (7–20 weight % (wt.%) Co) were prepared by vacuum arc melting, aiming at investigating the influence of the cobalt content on the microstructure and corrosion behavior. Quite uniform and directional microstructures were attained. The obtained microstructures depended on the Co content, ranging from fully eutectic growth (7 wt.% and 10 wt.% Co) to coarse primary Al9Co2 predominance (20 wt.% Co). Co dissolution in Al far exceeded the negligible ...

  11. Effect of Counterion and Configurational Entropy on the Surface Tension of Aqueous Solutions of Ionic Surfactant and Electrolyte Mixtures

    OpenAIRE

    Youichi Takata; Hiroaki Tagashira; Atsushi Hyono; Hiroyuki Ohshima

    2010-01-01

    In order to clarify the adsorption behavior of cationic surfactants on the air/aqueous electrolyte solution surface, we derived the theoretical equation for the surface tension. The equation includes the electrical work required for charging the air/water surface and the work attributable to the configurational entropy in the adsorbed film. By fitting the equation to the experimental data, we determined the binding constant between adsorbed surfactant ion and counterion, and found that the br...

  12. Aqueous fluids and sedimentary melts as agents for mantle wedge metasomatism, as inferred from peridotite xenoliths at Pinatubo and Iraya volcanoes, Luzon arc, Philippines

    Science.gov (United States)

    Yoshikawa, Masako; Tamura, Akihiro; Arai, Shoji; Kawamoto, Tatsuhiko; Payot, Betchaida D.; Rivera, Danikko John; Bariso, Ericson B.; Mirabueno, Ma. Hannah T.; Okuno, Mitsuru; Kobayashi, Tetsuo

    2016-10-01

    Mantle xenoliths entrained in subduction-zone magmas often record metasomatic signature of the mantle wedge. Such xenoliths occur in magmas from Iraya and Pinatubo volcanoes, located at the volcanic front of the Luzon arc in the Philippines. In this study, we present the major element compositions of the main minerals, trace element abundances in pyroxenes and amphiboles, and Nd-Sr isotopic compositions of amphiboles in the peridotite xenoliths from Pinatubo volcano. The data indicate enrichment in fluid-mobile elements, such as Rb, Ba, U, Pb, and Sr, and Nd-Sr isotopic ratios relative to those of mantle. The results are considered in terms of mixing of asthenospheric mantle and subducting oceanic crustal components. The enrichments observed in the Pinatubo mantle xenoliths are much less pronounced than those reported for the Iraya mantle xenoliths. This disparity suggests differences in the metasomatic agents contributing to the two suites; i.e., aqueous fluids infiltrated the mantle wedge beneath the Pinatubo volcano, whereas aqueous fluids and sediment-derived melts infiltrated the mantle wedge beneath the Iraya volcano.

  13. Preparation of non-aggregating aqueous fullerenes in highly saline solutions with a biocompatible non-ionic polymer

    Science.gov (United States)

    Aich, Nirupam; Boateng, Linkel K.; Flora, Joseph R. V.; Saleh, Navid B.

    2013-10-01

    Size-tunable stable aqueous fullerenes were prepared with different concentrations of biocompatible block-copolymer pluronic (PA) F-127, ranging from 0.001% to 1% (w/v). Size uniformity increased with the increase in PA concentration, yielding optimum 58.8 ± 5.6 and 61.8 ± 5.6 nm nC60s and nC70s, respectively (0.10%w/v PA), as observed using a dynamic light scattering technique. Fullerene aqueous suspensions also manifested enhanced stability in saline solution, Dulbecco’s modified Eagle medium (DMEM), and Roswell Park Memorial Institute (RPMI) culture medium. Transmission electron microscopy was performed to elaborate on the morphology and size specificity of fullerene clusters. Physicochemical characterizations of the suspended fullerenes were performed through UV-vis spectroscopy and electrophoretic mobility measurements. PA molecules showed size restriction by encasement, as observed via molecular dynamics simulations. Such solubilization with controllable size and non-aggregating behavior can facilitate application enhancement and mechanistic environmental and toxicological studies of size-specific fullerenes.

  14. Al-Co Alloys Prepared by Vacuum Arc Melting: Correlating Microstructure Evolution and Aqueous Corrosion Behavior with Co Content

    Directory of Open Access Journals (Sweden)

    Angeliki Lekatou

    2016-02-01

    Full Text Available Hypereutectic Al-Co alloys of various Co contents (7–20 weight % (wt.% Co were prepared by vacuum arc melting, aiming at investigating the influence of the cobalt content on the microstructure and corrosion behavior. Quite uniform and directional microstructures were attained. The obtained microstructures depended on the Co content, ranging from fully eutectic growth (7 wt.% and 10 wt.% Co to coarse primary Al9Co2 predominance (20 wt.% Co. Co dissolution in Al far exceeded the negligible equilibrium solubility of Co in Al; however, it was hardly uniform. By increasing the cobalt content, the fraction and coarseness of Al9Co2, the content of Co dissolved in the Al matrix, and the hardness and porosity of the alloy increased. All alloys exhibited similar corrosion behavior in 3.5 wt.% NaCl with high resistance to localized corrosion. Al-7 wt.% Co showed slightly superior corrosion resistance than the other compositions in terms of relatively low corrosion rate, relatively low passivation current density and scarcity of stress corrosion cracking indications. All Al-Co compositions demonstrated substantially higher resistance to localized corrosion than commercially pure Al produced by casting, cold rolling and arc melting. A corrosion mechanism was formulated. Surface films were identified.

  15. Effect of Counterion and Configurational Entropy on the Surface Tension of Aqueous Solutions of Ionic Surfactant and Electrolyte Mixtures

    Directory of Open Access Journals (Sweden)

    Youichi Takata

    2010-04-01

    Full Text Available In order to clarify the adsorption behavior of cationic surfactants on the air/aqueous electrolyte solution surface, we derived the theoretical equation for the surface tension. The equation includes the electrical work required for charging the air/water surface and the work attributable to the configurational entropy in the adsorbed film. By fitting the equation to the experimental data, we determined the binding constant between adsorbed surfactant ion and counterion, and found that the bromide ions, rather than the chloride ions, are preferentially adsorbed by the air/water surface. Furthermore, it was suggested that the contribution of configurational entropy to the surface tension is predominant in the presence of electrolytes because of the increase in the surface density of surfactant molecules associated with decreasing the repulsive interaction between their hydrophilic groups.

  16. Aqueous cationic, anionic and non-ionic multi-walled carbon nanotubes, functionalised with minimal framework damage, for biomedical application

    Science.gov (United States)

    Chen, Shu; Hu, Sheng; Smith, Elizabeth F.; Ruenraroengsak, Pakatip; Thorley, Andrew J.; Menzel, Robert; Goode, Angela E.; Ryan, Mary P.; Tetley, Teresa D.; Porter, Alexandra E.; Shaffer, Milo S. P.

    2014-01-01

    The use of a thermochemical grafting approach provides a versatile means to functionalise as-synthesised, bulk multi-walled carbon nanotubes (MWNTs) without altering their inherent structure. The associated retention of properties is desirable for a wide range of commercial applications, including for drug delivery and medical purposes; it is also pertinent to studies of intrinsic toxicology. A systematic series of water-compatible MWNTs, with diameter around 12 nm have been prepared, to provide structurally-equivalent samples predominantly stabilised by anionic, cationic, or non-ionic groups. The surface charge of MWNTs was controlled by varying the grafting reagents and subsequent post-functionalisation modifications. The degree of grafting was established by thermal analysis (TGA). High resolution transmission electron microscope (HRTEM) and Raman measurements confirmed that the structural framework of the MWNTs was unaffected by the thermochemical treatment, in contrast to a conventional acid-oxidised control which was severely damaged. The effectiveness of the surface modification was demonstrated by significantly improved solubility and stability in both water and cell culture medium, and further quantified by zeta-potential analysis. The grafted MWNTs exhibited relatively low bioreactivity on human immortal alveolar epithelial type 1-like cells (TT1) following 24h exposure as demonstrated by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) and lactate dehydrogenase release (LDH) assays. The exposure of TT1 cells to MWNTs suppressed the release of the inflammatory mediators, interleukin 6 (IL-6) and interleukin 8 (IL-8). TEM cell uptake studies indicated efficient cellular entry of MWNTs into TT1 cells, via a range of mechanisms. Cationic MWNTs showed a more substantial interaction with TT1 cell membranes than anionic MWNTs, demonstrating a surface charge effect on cell uptake. PMID:24631251

  17. Ionic liquid-based ultrasound-assisted extraction and aqueous two-phase system for analysis of caffeoylquinic acids from Flos Lonicerae Japonicae.

    Science.gov (United States)

    Tan, Ting; Lai, Chang-Jiang-Sheng; OuYang, Hui; He, Ming-Zhen; Feng, Yulin

    2016-02-20

    In this work, an ionic liquid-based ultrasonic-assisted extraction (ILUAE) method was developed to extract caffeoylquinic acids (CQAs) from Flos Lonicerae Japonicae (FLJ). ILUAE parameters were optimized by response surface methodology, including IL concentration, ultrasonic time, and liquid-solid ratio. Optimized ILUAE approach gained the highest extraction yields of 28.53, 18.21, 3.84mg/g for 3-O-caffeoylquinic acid (C1), 3,5-di-O-caffeoylquinic acid (C2), 3,4-di-O-caffeoylquinic acid (C3), respectively. C1-C3 are the three most abundant CQAs compounds in FLJ. The method showed comparable extraction yield and shorter extraction time compared with conventional extraction techniques. Subsequently, an aqueous two-phase system (ATPS) was applied in extraction solutions. Two trace CQAs, 5-O-caffeoylquinic acid (C4) and 4,5-di-O-caffeoylquinic acid (C5), were significantly enriched with signal to noise values increasing from less than 10 to higher than 1475. The results indicated that ILUAE and ATPS are efficient and environmentally-friendly sample extraction and enrichment techniques for CQAs from herbal medicines. PMID:26730510

  18. Comparing an ionic liquid to a molecular solvent in the cesium cation extraction by a calixarene: a molecular dynamics study of the aqueous interfaces.

    Science.gov (United States)

    Sieffert, Nicolas; Wipff, Georges

    2006-10-01

    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.

  19. Extraction, Preconcentration and Isolation of Flavonoids from Apocynum venetum L. Leaves Using Ionic Liquid-Based Ultrasonic-Assisted Extraction Coupled with an Aqueous Biphasic System

    Directory of Open Access Journals (Sweden)

    Zhijian Tan

    2016-03-01

    Full Text Available Background: Ionic liquids (ILs are considered as green solvents, and widely applied for the extraction of various compounds. Methods: The present research focuses on the extraction of flavonoids from Apocynum venetum L. leaves by ultrasound-assisted extraction (UAE. Several major influencing factors were optimized. Then, an aqueous biphasic system (ABS was applied for further isolation of flavonoids. Results: The flavonoids were mainly distributed in the top phase, while impurities were extracted to the bottom phase. The parameters influencing the extraction, namely type and concentration of salt, temperature, and pH, were studied in detail. Under optimized conditions (72.43% IL extract, 28.57% (NH42SO4, 25 °C temperature, pH 4.5, the preconcentration factor and extraction efficiency were found to be 3.78% and 93.35%, respectively. Conclusions: This simple and efficient methodology is expected to see great use in the extraction and isolation of pharmaceutically active components from medicinal plant resources.

  20. 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.

    Science.gov (United States)

    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.

  1. Removal of malachite green dye from aqueous solution using mesoporous silica synthesized from 1-octyl-3-methylimidazolium chloride ionic liquid

    Science.gov (United States)

    Ekka, Basanti; Nayak, Soumitra Ranjan; Dash, Priyabrat; Patel, Raj Kishore

    2016-04-01

    In this research, mesoporous silica was synthesized via a modified sol-gel route using 1-octyl-3-methylimidazolium chloride and was employed to remove malachite green (MG) dye from aqueous solution. Subsequently, this material was characterized and identified by different techniques such as Fourier transform infrared spectroscopy (FT-IR), N2 adsorption-desorption method, scanning electron microscopy (SEM), and thermosgravimetric analysis (TGA). Unique properties such as high surface area and pore diameter, in addition to highly reactive atoms and presence of various functional groups make the mesoporous silica possible for efficient removal of malachite green (MG). In batch experimental set-up, optimum conditions for quantitative removal of MG by mesoporous silica was attained by varying different variables such as adsorbent dosage, initial dye concentration, contact time, and pH. Optimum values were set as pH of 8.0, 0.5 g of adsorbent at contact time of 120 min. The adsorption of MG follows the pseudo-second-order rate equation. Equilibrium data fitted well with the Freundlich model at all amount of adsorbent, while maximum adsorption capacity was 5.981 mg g-1 for 0.5 g mesoporous silica synthesized in IL.

  2. Extraction and Chromatographic Determination of Shikimic Acid in Chinese Conifer Needles with 1-Benzyl-3-methylimidazolium Bromide Ionic Liquid Aqueous Solutions

    OpenAIRE

    2014-01-01

    An ionic liquids-based ultrasound-assisted extraction (ILUAE) method was successfully developed for extracting shikimic acid from conifer needles. Eleven 1-alkyl-3-methylimidazolium ionic liquids with different cations and anions were investigated and 1-benzyl-3-methylimidazolium bromide solution was selected as the solvent. The conditions for ILUAE, including the ionic liquid concentration, ultrasound power, ultrasound time, and liquid-solid ratio, were optimized. The proposed method had goo...

  3. Glass transition dynamics and conductivity scaling in ionic deep eutectic solvents: The case of (acetamide + lithium nitrate/sodium thiocyanate) melts

    Energy Technology Data Exchange (ETDEWEB)

    Tripathy, Satya N., E-mail: satyanarayantripathy@gmail.com; Wojnarowska, Zaneta; Knapik, Justyna; Paluch, Marian [Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice (Poland); Silesian Center for Education and Interdisciplinary Research, 75 Pulku Piechoty 1A, 41-500 Chorzow (Poland); Shirota, Hideaki [Department of Nanomaterial Science and Department of Chemistry, Chiba University, 1-33 Yayoi, Inage-ku, Chiba 263-8522 (Japan); Biswas, Ranjit [Department of Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700098 (India)

    2015-05-14

    A detailed investigation on the molecular dynamics of ionic deep eutectic solvents (acetamide + lithium nitrate/sodium thiocyanate) is reported. The study was carried out employing dielectric relaxation spectroscopy covering seven decades in frequency (10{sup −1}-10{sup 6} Hz) and in a wide temperature range from 373 K down to 173 K, accessing the dynamic observables both in liquid and glassy state. The dielectric response of the ionic system has been presented in the dynamic window of modulus formalism to understand the conductivity relaxation and its possible connection to the origin of localized motion. Two secondary relaxation processes appear below glass transition temperature. Our findings provide suitable interpretation on the nature of secondary Johari-Goldstein process describing the ion translation and orientation of dipoles in a combined approach using Ngai’s coupling model. A nearly constant loss feature is witnessed at shorter times/lower temperatures. We also discuss the ac conductivity scaling behavior using Summerfield approach and random free energy barrier model which establish the time-temperature superposition principle. These experimental observations have fundamental importance on theoretical elucidation of the conductivity relaxation and glass transition phenomena in molten ionic conductors.

  4. Retarded ionic motion in flourites

    NARCIS (Netherlands)

    Schoonman, J.

    1980-01-01

    Metals halides with the fluorite structure attain conductivity values typical of ionic melts far below their melting points, and also go through a second-order transition. Conductivity data for the fluorites are reviewed, and it is shown that the anion vacancies have a large and unique mobility valu

  5. Explaining Ionic Liquid Water Solubility in Terms of Cation and Anion Hydrophobicity

    Directory of Open Access Journals (Sweden)

    Johannes Ranke

    2009-03-01

    Full Text Available The water solubility of salts is ordinarily dictated by lattice energy and ion solvation. However, in the case of low melting salts also known as ionic liquids, lattice energy is immaterial and differences in hydrophobicity largely account for differences in their water solubility. In this contribution, the activity coefficients of ionic liquids in water are split into cation and anion contributions by regression against cation hydrophobicity parameters that are experimentally determined by reversed phase liquid chromatography. In this way, anion hydrophobicity parameters are derived, as well as an equation to estimate water solubilities for cation-anion combinations for which the water solubility has not been measured. Thus, a new pathway to the quantification of aqueous ion solvation is shown, making use of the relative weakness of interactions between ionic liquid ions as compared to their hydrophobicities.

  6. Modelization of flow electrification in a polymer melt

    CERN Document Server

    Flores, F; Allal, A; Guerret-Piécourt, C

    2007-01-01

    Flow electrification of polymer melts is an important side effect of polymer processing. The studies dealing with this phenomenon are seldom and most of the scientific work has been focused on flow electrification of aqueous and insulating Newtonian liquids. From that prior art it is well established that the flow electrification in Newtonian liquids is a consequence of the formation of an ionic double layer. Convection of this layer induces the electrification of the liquid at the outlet of the pipe. In those models, the key parameters governing the flow electrification are thus the intrinsic electrical properties of the polymer and the flow characteristics. In this work, we reconsider the assumptions made previously and we propose a new approach to modelise the flow electrification in the particular case of non-Newtonian polymer materials in laminar flow conditions. We establish that, a key parameter for the electrification quantification in the polymer melt is the shape of the velocity profile. Additionall...

  7. Extraction and Chromatographic Determination of Shikimic Acid in Chinese Conifer Needles with 1-Benzyl-3-methylimidazolium Bromide Ionic Liquid Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Fengli Chen

    2014-01-01

    Full Text Available An ionic liquids-based ultrasound-assisted extraction (ILUAE method was successfully developed for extracting shikimic acid from conifer needles. Eleven 1-alkyl-3-methylimidazolium ionic liquids with different cations and anions were investigated and 1-benzyl-3-methylimidazolium bromide solution was selected as the solvent. The conditions for ILUAE, including the ionic liquid concentration, ultrasound power, ultrasound time, and liquid-solid ratio, were optimized. The proposed method had good recovery (99.37%–100.11% and reproducibility (RSD, n = 6; 3.6%. ILUAE was an efficient, rapid, and simple sample preparation technique that showed high reproducibility. Based on the results, a number of plant species, namely, Picea koraiensis, Picea meyeri, Pinus elliottii, and Pinus banksiana, were identified as among the best resources of shikimic acid.

  8. Fullerol ionic fluids

    KAUST Repository

    Fernandes, Nikhil

    2010-01-01

    We report for the first time an ionic fluid based on hydroxylated fullerenes (fullerols). The ionic fluid was synthesized by neutralizing the fully protonated fullerol with an amine terminated polyethylene/polypropylene oxide oligomer (Jeffamine®). The ionic fluid was compared to a control synthesized by mixing the partially protonated form (sodium form) of the fullerols with the same oligomeric amine in the same ratio as in the ionic fluids (20 wt% fullerol). In the fullerol fluid the ionic bonding significantly perturbs the thermal transitions and melting/crystallization behavior of the amine. In contrast, both the normalized heat of fusion and crystallization of the amine in the control are similar to those of the neat amine consistent with a physical mixture of the fullerols/amine with minimal interactions. In addition to differences in thermal behavior, the fullerol ionic fluid exhibits a complex viscoelastic behavior intermediate between the neat Jeffamine® (liquid-like) and the control (solid-like). © 2010 The Royal Society of Chemistry.

  9. One-pot three-component synthesis of tetrahydrobenzo[b]pyrans catalyzed by cost-effective ionic liquid in aqueous medium☆

    Institute of Scientific and Technical Information of China (English)

    Jianguo Yang; Shuo Liu; Huanan Hu; Shibin Ren; Anguo Ying

    2015-01-01

    A simple and efficient method is proposed for the synthesis of tetrahydrobenzo[b]pyrans with aromatic alde-hydes, active methylene compounds, and dimedone using basic ionic liquid catalyst in water. The procedure offers several advantages including short reaction time, good yield, easy procedure, and good recyclability of catalysts, which may be a practical alternative to conventional processes for preparation of 4-hpyrans.

  10. Theoretical modeling of cationic surfactant aggregation at the silica/aqueous solution interface: Effects of pH and ionic strength

    NARCIS (Netherlands)

    Drach, M.; Andrzejewska, A.; Narkiewicz-Michalek, J.; Rudzinski, W.; Koopal, L.K.

    2002-01-01

    A theory of ionic surfactant aggregation on oppositely charged surfaces is presented. In the proposed model the adsorbed phase is considered as a mixture of singly dispersed surfactant molecules, monolayered and bilayered aggregates of various sizes and the ions of simple electrolyte added to the aq

  11. Determination of Vitamin B6 by Fluorimetry after Aqueous Two-Phase Extraction Based on Ionic Liquid%离子液体双水相萃取荧光法测定维生素B6

    Institute of Scientific and Technical Information of China (English)

    谢秀娟; 张振新

    2011-01-01

    Based on the fact that water-miscible sol vent, such as ionic liquid, can be used to form aqueous two-phase system for extraction of analytes in the presence of salts, ionic liquid-salt system of ionic liquid( [Bmim]Br )and(NH4)2SO4 was developed for the determination of trace vitamin B6 coupled with fluorimetry after aqueous two-phase extraction. Factors that affect the extraction efficiencies of vitamin B6 including pH, the amount of extractant and extraction time were well studied. Under the optimal conditions, I. E. , λex/λem = 342/418 nm,pH = 8. 69, 1. 3 mL ionic liquid, 2. 8 g ammonium sulfate and 3 min of extraction, the extraction method presented a linear range of 1. 6×10-7~l. 04×10-5 g/L with a detection limit of 4. 8 × 10-7 g/L.%基于离子液体在盐的作用下能够形成双水相,用于目标物质的萃取,提出了离子液体-硫酸铵双水相萃取、荧光法测定痕量维生素B6的新方法.实验探讨了影响维生素B6萃取率的主要因素,如酸度、萃取剂的用量、时间等.在最适条件下,即λex/λem=342/418 nm,pH=8.69,离子液体和硫酸铵的用量分别为1.3mL、2.8g,萃取3 min时,体系测定维生素B6的线性范围为1.6×10-7~1.04×10-5 g/L,检出限为4.8×10-7 g/L.

  12. Extraction of Doxycycline Hydrochloride Using Alcohol and Ionic Liquid Binary Aqueous Two Phase System%醇与离子液体二元双水相体系萃取盐酸多西环素

    Institute of Scientific and Technical Information of China (English)

    关卫省; 黎文娟; 韩娟

    2012-01-01

    Based on the molecular alcohol aqueous two-phase system and the ionic liquid aqueous two-phase system, the new method of using n-propanol and hydrophilic ionic liquid(1-butyl-3-methylimidazolium tetrafluoroborate, [Bmim]BF4) with (NH4)2SO4 binary aqueous two phase system for the extraction of doxycycline hydrochloride was developed. The influence factors on partition behaviors of doxycycline hydrochloride were studied, including concentration of (NH4)2SO4, n-propanol con-sumption, pH value, concentration of ionic liquid and doxycycline hydrochloride. The results showed that when using pH value of 4. 0 - 5. 0, (NH4) 2SO4 concentration of 34% and doxycycline hydrochloride concentration between 25 -95 mg/L, the extraction rate and distribution coefficient of doxycycline hydrochloride will be up to 90. 26% -95. 71% and 62. 452 - 149. 401, respectively.%基于小分子醇双水相体系和离子液体双水相体系,建立了正丙醇与亲水性离子液体1-丁基-3-甲基咪唑四氟硼酸[ Bmim]BF4和(NH4 )2SO4形成的二元双水相体系萃取盐酸多西环素的新方法.考察了(NH4)2SO4含量、正丙醇用量、pH值、离子液体含量以及盐酸多西环素含量对盐酸多西环素分配行为的影响.结果表明:当醇和离子液体二元双水相体系的pH值在4.0~5.0范围内,(NH4)2SO4含量为34%,且盐酸多西环素的质量浓度在25 ~ 95 mg/L之间时,该体系对盐酸多西环素的萃取率可达90.26% ~95.71%,分配系数可达62.452 ~ 149.401.

  13. Fission-Product Separation Based on Room-Temperature Ionic Liquids. Final Report

    International Nuclear Information System (INIS)

    During previous DOE sponsored research (DE-FG07-01ER63286), a process was developed for removing Cs+ and Sr2+ from simulated aqueous tank waste by extraction of these ions into a hydrophobic room-temperature ionic liquid solvent, tri-n-butylmethylammonium bis((trifluoromethyl)sulfonyl)imide, containing the ionophores, calix(4)arene-bis(tert-octylbenzo-crown-6) and dicyclohexano-18-crown-6. The coordinated Cs+ and Sr2+ could be removed from the ionic liquid extraction solvent by an electrochemical reduction process carried out at mercury electrodes. In this follow-up project, the effects of residual moisture and oxygen on this processing scheme were assessed. It was determined that the electrochemical reduction of ionophore-bound Cs+ at Hg electrodes is surprisingly tolerant of small amounts of water, but greatly affected by oxygen. However, sparging of the ionic liquid with dry N2 lowers the residual water and oxygen content of the extraction solvent to the level where the reduction of Cs+ at Hg is possible. Thus, the entire treatment cycle for the removal of Cs+ from tank waste using this approach can be carried out in an open cell, provided that the cell is continuously sparged with dry N2. (Due to a reduction in the funds designated for the project, it was not possible to investigate the effects of moisture and oxygen on the Sr2+ removal process.) Additional research carried out under this project led to the discovery and characterization of a new low-melting urea-based melt that can be used as an electrochemical solvent. This melt is less expensive to prepare than most of the well-know room-temperature ionic liquid solvents, has a better electrochemical window than existing urea-based melts, and has potential applications for the processing of nuclear waste. This melt is made by combining urea with the N,N-dialkylimidazolium salt, 1-ethyl-3-methylimidazolium chloride.

  14. Membrane separation of ionic liquid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Daniel; Feiring, Andrew Edward; Majumdar, Sudipto; Nemser, Stuart

    2015-09-01

    A membrane separation process using a highly fluorinated polymer membrane that selectively permeates water of an aqueous ionic liquid solution to provide dry ionic liquid. Preferably the polymer is a polymer that includes polymerized perfluoro-2,2-dimethyl-1,3-dioxole (PDD). The process is also capable of removing small molecular compounds such as organic solvents that can be present in the solution. This membrane separation process is suitable for drying the aqueous ionic liquid byproduct from precipitating solutions of biomass dissolved in ionic liquid, and is thus instrumental to providing usable lignocellulosic products for energy consumption and other industrial uses in an environmentally benign manner.

  15. Hydrogen production from glucose in ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Assenbaum, D.W.; Taccardi, N.; Berger, M.E.M.; Boesmann, A.; Enzenberger, F.; Woelfel, R.; Wasserscheid, P. [Erlangen-Nuernberg Univ. (Germany). Lehrstuhl fuer chemische Reaktionstechnik

    2010-07-01

    technologies suffer from the fact that the overall reaction rates are often restricted by mass and heat transport problems. Lastly, there are severe limitations concerning the feedstock selection as for some important substrates, such as e.g. glucose, the process can only be operated in very diluted systems to avoid rapid tar formation [22,23,24]. In this contribution we describe for the first time a catalytic reaction system producing hydrogen from glucose in astonishingly high selectivities using a single reaction step under very mild conditions. The catalytic reaction system is characterized by its homogeneous nature and comprises a Ru-complex catalyst dissolved and stabilized in an ionic liquid medium. Ionic liquids are salts of melting points below 100 C [25]. These liquid materials have attracted much interest in the last decade as solvents for catalytic reactions [26] and separation technologies (extraction, distillation) [27,28,29,30,31,32]. Besides, these liquids have found industrial applications as process fluids for mechanic [33] and electrochemical applications [34]. Finally, from the pioneering work of Rogers and co-workers, it is known that ionic liquids are able to dissolve significant amounts of water-insoluble biopolymers (such as e.g. cellulose and chitin)[35] and even complex biopolymer mixtures, such as e.g. wood, have been completely dissolved in some ionic liquids [36]. In our specific application, the role of the ionic liquid is threefold: a) the ionic liquid dissolves the carbohydrate starting material thus expanding the range of applicable carbohydrate to water insoluble polymers; b) the ionic liquid provides a medium to dissolve and stabilize the catalyst; c) the ionic liquid dissolves hydrogen at a very low level, so inhibiting any possible collateral hydrogen-consuming process (detailed investigation of the hydrogen solubility in ionic liquids have been reported by e.g. Brennecke and coworkers [37]). (orig.)

  16. Covalent and Ionic Molecules: Why Are BeF2 and AlF3 High Melting Point Solids whereas BF3 and SiF4 Are Gases?

    Science.gov (United States)

    Gillespie, Ronald J.

    1998-07-01

    Calculated ionic charges show that BF3 and SiF4 are predominately ionic molecules yet in contrast to BeF2 and AlF3 they exist as gases at room temperature and form molecular solids rather than infinite three-dimensional "ionic" solids at low temperature. Whether or not ionic molecules form a three-dimensional infinite ionic lattice or a molecular solid depends more on relative atomic (ionic) sizes than on the nature of the bonding in the isolated molecule. The ionic model for BF3 and BF4- provides a simple explanation of their bond lengths and for the constancy of interligand nonbonding distances. BF3 and SiF4 should be represented by ionic structures rather than by the conventional structures with bond lines that are normally assumed to indicate covalent bonds. A letter from Lawrence J. Sacks in our April 2000 issue addresses the above.

  17. Aldol condensation of aromatic aldehyde and aromatic ketone promoted by ionic liquid-aqueous system%离子液体/水体系促进芳醛与芳酮Aldol缩合反应

    Institute of Scientific and Technical Information of China (English)

    郑惠榕; 林棋

    2012-01-01

    研究1-甲基-3-丁基咪唑对甲苯磺酸盐([bmim][p-CH3C6H4SO3])离子液体/水体系促进室温下碱催化芳醛与芳酮Aldol缩合反应.实验结果显示,在室温下,离子液体体积分数为25%,离子液体/水体系对苯甲醛与苯乙酮间Aldol缩合反应具有更明显的加速作用,缩合产物收率达到81%以上;该方法具有条件温和、操作简单、反应时间短、产率高等特点.%The paper reported that the aldol reaction of aromatic aldehyde and aromatic ketone at room temperature could be efficiently promoted by the use of mixed solvent of ionic liquid 3-butyl-1-methylimidazolium p-toluenesulfonate([p-CH3C6H4SO3]) and water.The results show the ionic liquid/aqueous mixture could efficiently accelerate the reaction of the aldol condensation and the yield could reach up to 81% at room temperature in the presence of 25% volume ionic liquid.The present protocol may offer several advantages including mild reaction conditions,simple work-up procedure,short reaction time and high yields.

  18. Thermodynamic Properties of Caprolactam Ionic Liquids

    Institute of Scientific and Technical Information of China (English)

    JIANG Lu; BAI Liguang; ZHU Jiqin; CHEN Biaohua

    2013-01-01

    A series of caprolactam ionic liquids (ILs) containing incorporated halide anions were synthesized.Their physical properties,such as melting points,heats of fusion and heat capacities,were measured by differential scanning calorimeter (DSC).The results indicate that these ionic liquids exhibit proper melting points,high value of heats of fusion,and satisfying heat capacities which are suitable for thermal energy storage applications.

  19. First title: Ionic liquids-useful reaction green solvents for the future Second title: ionic liquids are the replacements for environmentally damaging solvents in a wide range of chemical processes.

    Directory of Open Access Journals (Sweden)

    K.Vijaya Bhaskar

    2012-09-01

    Full Text Available Ionic liquids (IL represent fascinating new class of solvents with unusual physical and chemical properties; low melting salts (up to 1000C. The main driving force for research in this area is the need to find replacement for environmentally damaging solvents in a wide range of chemical processes. To date, most chemical reactions have been carried out in molecular solvents. For the past twenty years, most of our understanding of our chemistry has been based upon the behavior of molecules in the solution phase in molecular solvents. Recently a new class of solvents has emerged called as Ionic liquids. An ionic liquid is an organic salt in which the ions are poorly coordinated, which results in these solvents being liquid below 100°C, or even at room temperature (room temperature ionic liquids, RTIL's. At least one ion has a delocalized charge and one component is organic, which prevents the formation of a stable crystal lattice. Ionic liquids are composed entirely of ions. For example, molten sodium chloride is an ionic liquid; in contrast, a solution of sodium chloride in water (a molecular solvent is an ionic solution. The term “ionic liquids” has replaced the older phrase “molten salts” (or “melts”, which suggests that they are high-temperature, corrosive, viscous media (like molten minerals. The reality is that ionic liquids can be liquid at temperatures as low as –96°C. Furthermore, room-temperature ionic liquids are frequently colourless, fluid, and easy to handle. In the patent and academic literature, the term “ionic liquids” now refers to liquids composed entirely of ions that are fluid around or below 100°C1. Properties, such as melting point, viscosity, and solubility of starting materials and other solvents, are determined by the substituents on the organic component and by the counter ion. Many ionic liquids have even been developed for specific synthetic problems. For this reason, ionic liquids have been termed

  20. SDS/[C_nmim]Br/H_2O体系的双水相性质%Aqueous Two-Phase System(ATPS) Containing Ionic Liquids [C_nmim]Br and SDS

    Institute of Scientific and Technical Information of China (English)

    陈婷; 马爱青; 王菲; 尚亚卓; 刘洪来

    2012-01-01

    研究了咪唑类离子液体[Cnmim]Br与传统阴离子表面活性剂SDS混合水溶液的性质,结果显示混合水溶液性质随咪唑阳离子上烷烃链长的变化而呈现出明显的不同。当离子液体取代烷基链的碳数大于或等于6时,混合体系可以自发地分为共存的两相,即双水相。共存的两相界面清晰、性能稳定且能有效萃取染料二甲酚橙,有望成为新型高效的分离体系,在生物活性物质的纯化、分离中发挥作用。混合体系中离子液体和传统表面活性剂相对含量的改变引起混合溶液中表面活性剂聚集体尺寸和形态的变化,最终导致双水相上、下两相表观现象的差异。此外,离子液体、SDS头基间库仑力作用、烷烃链的疏溶剂力以及离子液体与SDS的协同效应,是形成溶致液晶的重要驱动力,导致较低浓度下十字花纹理层状液晶(LC)的生成。%Properties of mixed aqueous solutions of ionic liquid(Br) and traditional surfactant(SDS) were studied.Results showed that the properties of the mixed systems varied with the chain length of substituted alkyl in ionic liquids.Only those systems containing ionic liquids with equal to or more than 6 carbon atoms in alkyl chains can form aqueous two phase system(ATPS).The ATPS containing ionic liquids and surfactant has obvious extraction ability to xylenol orange and the potential to separate and purify biomaterials.The difference in appearance of ATPS should be attributed to the various size and shape of the surfactants aggregates formed in mixed solutions.Furthermore,the electrostatic attractive interaction,the hydrophobic interaction in addition to the synergistic effect between ionic liquids and SDS further promote the surfactant assembly,which leads to the formation of liquid crystal at lower surfactant concentration.

  1. Ionic liquids as electrolytes for non-aqueous solutions electrochemical supercapacitors in a temperature range of 20 °C-80 °C

    Science.gov (United States)

    Zhang, Lei; Tsay, Ken; Bock, Christina; Zhang, Jiujun

    2016-08-01

    To increase the operating temperature of the supercapacitors (SCs) without compromising their high cycle-life, several typical fluoro- and non-fluoro containing ionic liquids (EMI-mesylate, EMI-hydrogen sulfate, PP13-triflate, PP13-TFSI, and EMI-TFSI, as shown in Fig. 1) are studied as the electrolytes to prepare organic solutions for SC performance measurements using a two-electrode cell. Both cyclic voltammograms and charge/discharge curves at various temperatures such as 20, 40, 60 and 80 °C are collected. At 60 °C, the increased performance order in both rating and cyclability measurements are found to be as follows: 1) EMI-hydrogen sulfate liquids can be used for SC electrolytes operated at high temperature.

  2. A comparative study for adsorption of lysozyme from aqueous samples onto Fe3O4 magnetic nanoparticles using different ionic liquids as modifier.

    Science.gov (United States)

    Kamran, Sedigheh; Absalan, Ghodratollah; Asadi, Mozaffar

    2015-12-01

    In this paper, nanoparticles of Fe3O4 as well as their modified forms with different ionic liquids (IL-Fe3O4) were prepared and used for adsorption of lysozyme. The mean size and the surface morphology of the nanoparticles were characterized by TEM, XRD and FTIR techniques. Adsorption studies of lysozyme were performed under different experimental conditions in batch system on different modified magnetic nanoparticles such as, lysozyme concentration, pH of the solution, and contact time. Experimental results were obtained under the optimum operational conditions of pH 9.0 and a contact time of 10 min when initial protein concentrations of 0.05-2.0 mg mL(-1) were used. The isotherm evaluations revealed that the Langmuir model attained better fits to the equilibrium data than the Freundlich model. The maximum obtained adsorption capacities were 370.4, 400.0 500.0 and 526.3 mg of lysozyme for adsorption onto Fe3O4 and modified magnetic nanoparticles by [C4MIM][Br], [C6MIM][Br] and [C8MIM][Br] per gram of adsorbent, respectively. The Langmuir adsorption constants were 0.004, 0.019, 0.024 and 0.012 L mg(-1) for adsorptions of lysozyme onto Fe3O4 and modified magnetic nanoparticles by [C4MIM][Br], [C6MIM][Br] and [C8MIM][Br], respectively. The adsorption capacity of lysozyme was found to be dependent on its chemical structure, pH of the solution, temperature and type of ionic liquid as modifier. The applicability of two kinetic models including pseudo-first order and pseudo-second order model was estimated. Furthermore, the thermodynamic parameters were calculated. Protein could desorb from IL-Fe3O4 nanoparticles by using NaCl solution at pH 9.5 and was reused.

  3. Partitioning behavior and structural characterization of papain in ionic liquid aqueous two-phase system%木瓜蛋白酶在离子液体双水相中的分配行为

    Institute of Scientific and Technical Information of China (English)

    王伟涛; 蒋志国; 张海德; 彭健; 许英豪; 董安华; 杨雪芳; 蒋欣欣

    2015-01-01

    Papain was extracted by ionic liquid aqueous two-phase system. Firstly,the influence of concentration, pH, and temperature of ionic liquid on the activity of papain was investigated. Secondly, the effects of different ionic liquid aqueous two-phase systems, alkyl chain lengths and concentrations of the ionic liquid, dosage of papain, pH, temperature on the partitioning behavior of papain were discussed. [C4mim]Cl and [C4mim]Br systems were better than [C4mim]BF4 system in extraction of papain, and it was disadvantageous to extract papain at a high temperature (60℃or higher). Activity recovery of enzyme reached 95.16%and purification factor reached 1.5 under the optimum conditions:[C4mim]Cl 0.25 g·ml−1, K2HPO4 0.35 g·ml−1, pH 8.0, enzyme addition 2.0 mg·ml−1, 30℃. The result laid the experimental basis for further scale-up research and commercial production.%采用离子液体双水相提取木瓜蛋白酶。首先考察不同浓度、pH、温度的离子液体对木瓜蛋白酶活性的影响,其次考察不同离子液体双水相体系、离子液体侧烷基链长度及浓度、酶添加量、pH、温度对木瓜蛋白酶分配行为的影响。结果表明:[C4mim]Cl 和[C4mim]Br 体系萃取木瓜蛋白酶的效果比[C4mim]BF4体系好;高温(≥60℃)对离子液体双水相体系萃取木瓜蛋白酶不利。离子液体双水相萃取木瓜蛋白酶的最佳工艺条件:0.25 g·ml−1的[C4mim]Cl,0.35 g·ml−1的K2HPO4,pH 8.0,酶添加量2.0 mg·ml−1,30℃。此条件下木瓜蛋白酶的酶活性回收率达到95.16%,纯化因子达到1.5。为今后进一步研究该体系的放大实验或规模化生产奠定了基础。

  4. Learning Ionic

    CERN Document Server

    Ravulavaru, Arvind

    2015-01-01

    This book is intended for those who want to learn how to build hybrid mobile applications using Ionic. It is also ideal for people who want to explore theming for Ionic apps. Prior knowledge of AngularJS is essential to complete this book successfully.

  5. Phase behavior, diffusion, structural characteristics, and pH of aqueous hydrophobic ionic liquid confined media: insights into microviscosity and microporsity in the [C4C4im][NTf2] + water system.

    Science.gov (United States)

    Nanda, Raju; Kumar, Anil

    2015-01-29

    We present our studies on the physicochemical properties of water confined in Dibutylimidazolium bis(trifluoromethanesulfonylimide) ([C4C4im][NTf2]) reverse micelles through the NMR relaxation measurements that provide us an understanding of microviscosity and pH in the confined condition. We present experimental results on phase behavior, diffusion, structural characteristics and pH in aqueous ionic liquid-confined media. The ternary phase diagram was constructed by the cloud point measurements and the microheterogeneous regions were detected by the measurement of bulk viscosity and diffusion coefficients of K4[Fe(CN)6] inside the homogeneous microemulsion systems through the cyclic voltammetric (CV) measurements. The size of the microemulsion systems was characterized by the dynamic light scattering (DLS) method. The (1)H NMR spectra of homogeneous microemulsion systems were taken which indicates the presence of bound and free water molecules inside the microemulsion system. The NMR spin-lattice relaxation time (T1) of water molecules in its homogeneous microemulsion systems were measured and the reorientational correlation time (τc) of water molecules obtained from it indicates that the fluidity of homogeneous confined media decreases with the decrease in the composition of water. Microviscosity of the aqueous confined media was calculated from the measured T1 relaxation time values by applying the Debye-Stokes equation and correlated with the bulk viscosity of the samples. It was observed that both the microviscosity and bulk viscosity show inverse relationship. The fraction of bound and free water molecules were calculated from the measured T1 values. NMR spin-spin relaxation time (T2) of water molecules in its homogeneous microemulsion systems were measured with the varying pH of the aqueous core. A change in the T2 relaxation time of the water proton was observed proposing an exchange of proton between the H2O and -OH group of the TX-100 molecules. Finally

  6. 离子液体双水相萃取山楂黄酮和多糖的研究%Study on the Extraction of Hawthorn Flavonoids and Polysaccharide in Ionic Liquid Aqueous Two-Phase System

    Institute of Scientific and Technical Information of China (English)

    巩育军; 牛盛童; 黄学锋; 王键

    2014-01-01

    Partition behaviors of hawthorn flavonoids and polysaccharide in ionic liquid aqueous two-phase system(ILATPS)were studied by spectrophotometry.Effects of concentration of ionic liquid and ammonium sulfate,dosage of hawthorn and ultrasonic time on the extraction rate of hawthorn flavonoids and polysaccharide were investigated.The optimal extraction conditions were as follows:concentration of ionic liquid [Bmim]BF4 was 0.26~0.30 g·mL-1,concentration of ammonium sulfate was 0.08~0.10 g·mL-1,dosage of hawthorn was 0.14~0.17 g,ultrasonic time was 15~20 min.Under these conditions,extraction rate of hawthorn fla-vonoids was 86.4%~96.0% in the up phase,and extraction rate of polysaccharide was 75.2%~76.0% in the down phase.%采用分光光度法研究了山楂黄酮和多糖在[Bmim]BF4/(NH4)2 SO4双水相体系的分配行为,探讨了离子液体浓度、(NH4)2 SO4浓度、山楂用量和超声时间等因素对山楂黄酮和多糖萃取率的影响。确定最佳萃取条件为:离子液体[Bmim]BF4浓度0.26~0.30 g·mL-1,(NH4)2 SO4浓度0.08~0.10 g·mL-1,山楂用量0.14~0.17 g,超声时间15~20 min,在此优化条件下,双水相上相中黄酮的萃取率为86.4%~96.0%、下相中多糖的萃取率为75.2%~76.0%。

  7. Synthesis, characterization and thermal properties of thiosalicylate ionic liquids

    Indian Academy of Sciences (India)

    Cecilia Devi Wilfred; Fadwa Babiker Mustafa

    2013-11-01

    In an attempt to produce new functionalized ionic liquids, a series of thiosalicylate ionic liquids based on imidazolium, ammonium, phosphonium, choline and pyrrolidinium cations were synthesized. The compounds were characterized by Infra Red (IR), Nuclear Magnetic Resonance (NMR) and mass spectra (ESI-MS). Their glass-transition temperatures, melting points and decomposition temperatures have been measured. Physicochemical properties of ionic liquids are influenced by alkyl chain length and nature of the cation of ionic liquids.

  8. Design of Separation Processes with Ionic Liquids

    DEFF Research Database (Denmark)

    Peng-noo, Worawit; Kulajanpeng, Kusuma; Gani, Rafiqul;

    2015-01-01

    A systematic methodology for screening and designing of Ionic Liquid (IL)-based separation processes is proposed and demonstrated using several case studies of both aqueous and non-aqueous systems, for instance, ethanol + water, ethanol + hexane, benzene + hexane, and toluene + methylcyclohexane...

  9. Nanoparticles in ionic liquids: interactions and organization.

    Science.gov (United States)

    He, Zhiqi; Alexandridis, Paschalis

    2015-07-28

    Ionic liquids (ILs), defined as low-melting organic salts, are a novel class of compounds with unique properties and a combinatorially great chemical diversity. Ionic liquids are utilized as synthesis and dispersion media for nanoparticles as well as for surface functionalization. Ionic liquid and nanoparticle hybrid systems are governed by a combined effect of several intermolecular interactions between their constituents. For each interaction, including van der Waals, electrostatic, structural, solvophobic, steric, and hydrogen bonding, the characterization and quantitative calculation methods together with factors affecting these interactions are reviewed here. Various self-organized structures based on nanoparticles in ionic liquids are generated as a result of a balance of these intermolecular interactions. These structures, including colloidal glasses and gels, lyotropic liquid crystals, nanoparticle-stabilized ionic liquid-containing emulsions, ionic liquid surface-functionalized nanoparticles, and nanoscale ionic materials, possess properties of both ionic liquids and nanoparticles, which render them useful as novel materials especially in electrochemical and catalysis applications. This review of the interactions within nanoparticle dispersions in ionic liquids and of the structure of nanoparticle and ionic liquid hybrids provides guidance on the rational design of novel ionic liquid-based materials, enabling applications in broad areas.

  10. Molecular dynamics simulation study of ionic hydration and ion association in dilute and 1 molal aqueous sodium chloride solutions from ambient to supercritical conditions

    Science.gov (United States)

    Driesner, T.; Seward, T. M.; Tironi, I. G.

    1998-09-01

    The increasing demand for accurate equations of state of fluids under extreme conditions and the need for a detailed microscopic picture of aqueous fluids in some areas of geochemistry (e.g., mineral dissolution/precipitation kinetics) potentially make molecular dynamics (MD) simulations a powerful tool for theoretical geochemistry. We present MD simulations of infinitely dilute and 1 molal aqueous NaCl solutions that have been carried out in order to study the systematics of hydration and ion association over a wide range of conditions from ambient to supercritical and compare them to the available experimental data. In the dilute case, the hydration number of the Na + ion remains essentially constant around 5.5 from ambient to supercritical temperatures when the density is kept constant at 1 g cm -3 but decreases to below 5 along the liquid-vapor curve. In both cases, the average ion-first shell water distance decreases by about 0.03 Å from ambient to near critical temperatures. The Cl - ion shows a slight expansion of the first hydration shell by about 0.02 Å from ambient to near critical temperatures. The geometric definition of the first hydration shell becomes ambiguous due to a shift of the position of the first minimum of the Cl-O radial distribution function. In the case of the 1 molal solution, the contraction of the Na + first hydration shell is similar to that in the dilute case whereas the hydration number decreases drastically from 4.9 to 2.8 due to strong ion association. The released waters are replaced on a near 1:1 basis by chloride ions. Polynuclear clusters as predicted by Oelkers and Helgeson (1993b) are observed in the high temperature systems. The hydration shell of the Cl --ion shows significant deviation from the behavior in dilute systems, that is, at near vapor saturated conditions, the expansion of the hydration shell is significantly larger (0.12 Å from ambient to near critical temperatures). Due to a very large shift of the first

  11. Analysis of mixed micellar behavior of cationic gemini alkanediyl-α,ω-bis(dimethylcetylammonium bromide) series with ionic and nonionic hydrotropes in aqueous medium at different temperatures.

    Science.gov (United States)

    Khan, Iqrar Ahmad; Khanam, Ahmad Jahan; Sheikh, Mohmad Shafi; Kabir-ud-Din

    2011-12-29

    The interaction between cationic symmetrical gemini alkanediyl-α,ω-bis(dimethylcetylammonium bromide) series (16-s-16, s = 5, 6, abbreviated as G5 and G6) with hydrotropes (cationic: aniline hydrochloride, para-toluidine hydrochloride, and ortho-toluidine hydrochloride; nonionic: phenol, resorcinol, and pyrogallol) in aqueous medium has been investigated at four different temperatures ranging from 298.15 to 313.15 K. Different physicochemical parameters such as critical micelle concentration (cmc), interaction parameter (β(m), an energetic parameter that represents the excess Gibbs free energy of mixing), activity coefficients (f(i)), mole fraction of hydrotrope in mixed micelles at ideal mixing conditions (X(1)(ideal))(,) excess free energy of mixing (Δ(mix)G(E)), standard enthalpy (Δ(mic)H°), entropy (Δ(mic)S°), and Gibbs free energy (Δ(mic)G°) of micellization were evaluated and then intracompared. For further understanding, similar studies were carried out with their conventional counterpart cetyltrimethyl ammonium bromide (CTAB) and then compared. The bulk behaviors were explored using different theoretical models of Clint, Rubingh, and Motomura for justification and comparison of results of different binary combinations of hydrotropes with the gemini series and CTAB. Synergistic interaction was observed in all binary combinations at all temperatures in the micelles which decreases slightly with increasing temperature. This study will give insight into the selection of surfactants in different applications as their properties get modified by interaction with hydrotropes, thus influencing their solution behavior which, in turn, modifying the phase-forming behavior, microemulsion, liquid crystal forming systems, clouding phenomenon, cleaning, and laundry processes besides solubilization. The ability of hydrotropes to dramatically alter the solubility of other molecules in a medium can be exploited for the purpose of selective encapsulation and release

  12. Synchrotron x-ray spectroscopy of EuHN O3 aqueous solutions at high temperatures and pressures and Nb-bearing silicate melt phases coexisting with hydrothermal fluids using a modified hydrothermal diamond anvil cell and rail assembly

    Science.gov (United States)

    Mayanovic, Robert A.; Anderson, Alan J.; Bassett, William A.; Chou, I.-Ming

    2007-01-01

    A modified hydrothermal diamond anvil cell (HDAC) rail assembly has been constructed for making synchrotron x-ray absorption spectroscopy, x-ray fluorescence, and x-ray mapping measurements on fluids or solid phases in contact with hydrothermal fluids up to ???900??C and 700 MPa. The diamond anvils of the HDAC are modified by laser milling grooves or holes, for the reduction of attenuation of incident and fluorescent x rays and sample cavities. The modified HDAC rail assembly has flexibility in design for measurement of light elements at low concentrations or heavy elements at trace levels in the sample and the capability to probe minute individual phases of a multiphase fluid-based system using focused x-ray microbeam. The supporting rail allows for uniform translation of the HDAC, rotation and tilt stages, and a focusing mirror, which is used to illuminate the sample for visual observation using a microscope, relative to the direction of the incident x-ray beam. A structure study of Eu(III) aqua ion behavior in high-temperature aqueous solutions and a study of Nb partitioning and coordination in a silicate melt in contact with a hydrothermal fluid are described as applications utilizing the modified HDAC rail assembly. ?? 2007 American Institute of Physics.

  13. Study on interaction between iron ( Ⅲ ) and pepsin in ionic liquid aqueous two-phase%离子液体双水相中铁(Ⅲ)与胃蛋白酶作用研究

    Institute of Scientific and Technical Information of China (English)

    王玉峰; 陈琳琳; 邓凡政

    2011-01-01

    The interaction between Fe3+ and the pepsin was investigated by fluorescence and UV absorption spectroscopy in ionic liquid aqueous two-phase. The results showed that the interactions,which resulted in the fluorescence quenching of pepsin, belonged to a static quenching mechanism. And by calculation the binding constants were 2. 56 × 105 L/mol (300 K) and 8. 91 × 104 L/mol (310 K) ,and the binding sites were 1. 21 (300 K) and 1. 14 (310 K) . The thermodynamic parameters showed that the in teraction between Fe3+ and pepsin was mainly driven by electrostatic force. Synchronous fluorescence spectrum was used to investigate the conformational change of pepsin.%运用荧光光谱和紫外光谱,研究了在离子液体双水相体系中铁(Ⅲ)与胃蛋白酶的相互作用.结果表明,Fe3+对胃蛋白酶产生了荧光猝灭作用,且属于静态猝灭过程.计算得到在300 K和310 K下的结合常数分别为2.56×105L/mol和8.91×104 L/mol,结合位点数分别为1.21和1.14.热力学参数表明,Fe3与胃蛋白酶之间的相互作用力类型为静电作用.用同步荧光法探讨了Fe3+对胃蛋白酶构象的影响.

  14. Ionic Liquids to Replace Hydrazine

    Science.gov (United States)

    Koelfgen, Syri; Sims, Joe; Forton, Melissa; Allan, Barry; Rogers, Robin; Shamshina, Julia

    2011-01-01

    A method for developing safe, easy-to-handle propellants has been developed based upon ionic liquids (ILs) or their eutectic mixtures. An IL is a binary combination of a typically organic cation and anion, which generally produces an ionic salt with a melting point below 100 deg C. Many ILs have melting points near, or even below, room temperature (room temperature ionic liquids, RTILs). More importantly, a number of ILs have a positive enthalpy of formation. This means the thermal energy released during decomposition reactions makes energetic ILs ideal for use as propellants. In this specific work, to date, a baseline set of energetic ILs has been identified, synthesized, and characterized. Many of the ILs in this set have excellent performance potential in their own right. In all, ten ILs were characterized for their enthalpy of formation, density, melting point, glass transition point (if applicable), and decomposition temperature. Enthalpy of formation was measured using a microcalorimeter designed specifically to test milligram amounts of energetic materials. Of the ten ILs characterized, five offer higher Isp performance than hydrazine, ranging between 10 and 113 seconds higher than the state-of-the-art propellant. To achieve this level of performance, the energetic cations 4- amino-l,2,4-triazolium and 3-amino-1,2,4-triazolium were paired with various anions in the nitrate, dicyanamide, chloride, and 3-nitro-l,2,4-triazole families. Protonation, alkylation, and butylation synthesis routes were used for creation of the different salts.

  15. Water in Room Temperature Ionic Liquids

    Science.gov (United States)

    Fayer, Michael

    2014-03-01

    Room temperature ionic liquids (or RTILs, salts with a melting point below 25 °C) have become a subject of intense study over the last several decades. Currently, RTIL application research includes synthesis, batteries, solar cells, crystallization, drug delivery, and optics. RTILs are often composed of an inorganic anion paired with an asymmetric organic cation which contains one or more pendant alkyl chains. The asymmetry of the cation frustrates crystallization, causing the salt's melting point to drop significantly. In general, RTILs are very hygroscopic, and therefore, it is of interest to examine the influence of water on RTIL structure and dynamics. In addition, in contrast to normal aqueous salt solutions, which crystallize at low water concentration, in an RTIL it is possible to examine isolated water molecules interacting with ions but not with other water molecules. Here, optical heterodyne-detected optical Kerr effect (OHD-OKE) measurements of orientational relaxation on a series of 1-alkyl-3-methylimidazolium tetrafluoroborate RTILs as a function of chain length and water concentration are presented. The addition of water to the longer alkyl chain RTILs causes the emergence of a long time bi-exponential orientational anisotropy decay. Such decays have not been seen previously in OHD-OKE experiments on any type of liquid and are analyzed here using a wobbling-in-a-cone model. The orientational relaxation is not hydrodynamic, with the slowest relaxation component becoming slower as the viscosity decreases for the longest chain, highest water content samples. The dynamics of isolated D2O molecules in 1-butyl-3-methylimidazolium hexafluorophosphate (BmImPF6) were examined using two dimensional infrared (2D IR) vibrational echo spectroscopy. Spectral diffusion and incoherent and coherent transfer of excitation between the symmetric and antisymmetric modes are examined. The coherent transfer experiments are used to address the nature of inhomogeneous

  16. A New Volume-Based Approach for Predicting Thermophysical Behavior of Ionic Liquids and Ionic Liquid Crystals.

    Science.gov (United States)

    Nelyubina, Yulia V; Shaplov, Alexander S; Lozinskaya, Elena I; Buzin, Mikhail I; Vygodskii, Yakov S

    2016-08-17

    Volume-based prediction of melting points and other properties of ionic liquids (ILs) relies on empirical relations with volumes of ions in these low-melting organic salts. Here we report an accurate way to ionic volumes by Bader's partitioning of electron densities from X-ray diffraction obtained via a simple database approach. For a series of 1-tetradecyl-3-methylimidazolium salts, the volumes of different anions are found to correlate linearly with melting points; larger anions giving lower-melting ILs. The volume-based concept is transferred to ionic liquid crystals (ILs that adopt liquid crystalline mesophases, ILCs) for predicting the domain of their existence from the knowledge of their constituents. For 1-alkyl-3-methylimidazolium ILCs, linear correlations of ionic volumes with the occurrence of LC mesophase and its stability are revealed, thus paving the way to rational design of ILCs by combining suitably sized ions. PMID:27479022

  17. Method and apparatus using an active ionic liquid for algae biofuel harvest and extraction

    Science.gov (United States)

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

    2012-11-06

    The invention relates to use of an active ionic liquid to dissolve algae cell walls. The ionic liquid is used to, in an energy efficient manner, dissolve and/or lyse an algae cell walls, which releases algae constituents used in the creation of energy, fuel, and/or cosmetic components. The ionic liquids include ionic salts having multiple charge centers, low, very low, and ultra low melting point ionic liquids, and combinations of ionic liquids. An algae treatment system is described, which processes wet algae in a lysing reactor, separates out algae constituent products, and optionally recovers the ionic liquid in an energy efficient manner.

  18. Paramagnetic ionic liquids for measurements of density using magnetic levitation.

    Science.gov (United States)

    Bwambok, David K; Thuo, Martin M; Atkinson, Manza B J; Mirica, Katherine A; Shapiro, Nathan D; Whitesides, George M

    2013-09-01

    Paramagnetic ionic liquids (PILs) provide new capabilities to measurements of density using magnetic levitation (MagLev). In a typical measurement, a diamagnetic object of unknown density is placed in a container containing a PIL. The container is placed between two magnets (typically NdFeB, oriented with like poles facing). The density of the diamagnetic object can be determined by measuring its position in the magnetic field along the vertical axis (levitation height, h), either as an absolute value or relative to internal standards of known density. For density measurements by MagLev, PILs have three advantages over solutions of paramagnetic salts in aqueous or organic solutions: (i) negligible vapor pressures; (ii) low melting points; (iii) high thermal stabilities. In addition, the densities, magnetic susceptibilities, glass transition temperatures, thermal decomposition temperatures, viscosities, and hydrophobicities of PILs can be tuned over broad ranges by choosing the cation-anion pair. The low melting points and high thermal stabilities of PILs provide large liquidus windows for density measurements. This paper demonstrates applications and advantages of PILs in density-based analyses using MagLev. PMID:23972068

  19. Aqueous biphasic systems with ionic liquids

    OpenAIRE

    Neves, Catarina Maia Seco Seiça

    2009-01-01

    O objectivo principal deste trabalho é estudar o equilíbrio de fases de líquidos iónicos em sistemas aquosos bifásicos. Para isso foram estudadas as solubilidades mútuas entre água e líquidos iónicos hidrofóbicos, e foi criado um modelo que descreve esta propriedade. Além disso, foram realizados e estudados sistemas aquosos bifásicos com líquidos iónicos hidrofílicos e o sal inorgânico K3PO4. Os líquidos iónicos são sais compostos por iões grandes que não formam uma rede cristalina b...

  20. Development of Monopole Interaction Models for Ionic Compounds. Part I: Estimation of Aqueous Henry’s Law Constants for Ions and Gas Phase pKa Values for Acidic Compounds

    Science.gov (United States)

    The SPARC (SPARC Performs Automated Reasoning in Chemistry) physicochemical mechanistic models for neutral compounds have been extended to estimate Henry’s Law Constant (HLC) for charged species by incorporating ionic electrostatic interaction models. Combinations of absolute aq...

  1. Modern ab initio valence bond theory calculations reveal charge shift bonding in protic ionic liquids.

    Science.gov (United States)

    Patil, Amol Baliram; Bhanage, Bhalchandra Mahadeo

    2016-06-21

    The nature of bonding interactions between the cation and the anion of an ionic liquid is at the heart of understanding ionic liquid properties. A particularly interesting case is a special class of ionic liquids known as protic ionic liquids. The extent of proton transfer in protic ionic liquids has been observed to vary according to the interacting species. Back proton transfer renders protic ionic liquids volatile and to be considered as inferior ionic liquids. We try to address this issue by employing modern ab initio valence bond theory calculations. The results indicate that the bonding in the cation and the anion of a prototypical ionic liquid, ethylammonium nitrate, is fundamentally different. It is neither characteristic of covalent/polar covalent bonding nor ionic bonding but rather charge shift bonding as a resonance hybrid of two competing ionic molecular electronic structure configurations. An investigation of other analogous protic ionic liquids reveals that this charge shift bonding seems to be a typical characteristic of protic ionic liquids while the ionic solid analogue compound ammonium nitrate has less charge shift bonding character as compared to protic ionic liquids. Further the extent of charge shift bonding character has been found to be congruent with the trends in many physicochemical properties such as melting point, conductivity, viscosity, and ionicity of the studied ionic liquids indicating that percentage charge shift character may serve as a key descriptor for large scale computational screening of ionic liquids with desired properties.

  2. Quantized ionic conductance in nanopores

    Energy Technology Data Exchange (ETDEWEB)

    Zwolak, Michael [Los Alamos National Laboratory; Lagerqvist, Johan [UCSD; Di Ventra, Massimilliano [UCSD

    2009-01-01

    Ionic transport in nanopores is a fundamentally and technologically important problem in view of its ubiquitous occurrence in biological processes and its impact on DNA sequencing applications. Using microscopic calculations, we show that ion transport may exhibit strong non-liDearities as a function of the pore radius reminiscent of the conductance quantization steps as a function of the transverse cross section of quantum point contacts. In the present case, however, conductance steps originate from the break up of the hydration layers that form around ions in aqueous solution. Once in the pore, the water molecules form wavelike structures due to multiple scattering at the surface of the pore walls and interference with the radial waves around the ion. We discuss these effects as well as the conditions under which the step-like features in the ionic conductance should be experimentally observable.

  3. Water-fluxed melting of the continental crust: A review

    Science.gov (United States)

    Weinberg, Roberto F.; Hasalová, Pavlína

    2015-01-01

    Water-fluxed melting, also known as fluid- or water-present melting, is a fundamental process in the differentiation of continents but its importance has been underestimated in the past 20 years during which research efforts focused mostly on dehydration melting reactions involving hydrate phases, in the absence of a separate aqueous phase. The presence of a free aqueous phase in anatectic terranes influences all major physical and chemical aspects of the melting process, from melt volumes, viscosity and ability to segregate from rock pores, to melt chemical and isotopic composition. A review of the literature shows that melting due to the fluxing of aqueous fluids is a widespread process that can take place in diverse tectonic environments. Active tectono-magmatic processes create conditions for the release of aqueous fluids and deformation-driven, transient high permeability channels, capable of fluxing high-temperature regions of the crust where they trigger voluminous melting. Water-fluxed melting can be either congruent in regions at the water-saturated solidus, or incongruent at suprasolidus, P-T conditions. Incongruent melting reactions can give rise to peritectic hornblende, or to nominally anhydrous minerals such as garnet, sillimanite or orthopyroxene. In this case, the presence of an aqueous phase is indicated by a mismatch between the large melt fraction generated and the much smaller fractions predicted in its absence. The relatively small volumes of aqueous fluids compared to that of rocks imply that melting reactions are generally rock buffered. Fluids tend to move upwards and down temperature. However, there are cases in which pressure gradients drive fluids up temperature, potentially fluxing suprasolidus terranes. Crustal regions at conditions equivalent to the water-saturated solidus represent a natural impediment to the up-temperature migration of aqueous fluids because they are consumed in melting reactions. In this case, continued migration

  4. Methods for Melting Temperature Calculation

    Science.gov (United States)

    Hong, Qi-Jun

    Melting temperature calculation has important applications in the theoretical study of phase diagrams and computational materials screenings. In this thesis, we present two new methods, i.e., the improved Widom's particle insertion method and the small-cell coexistence method, which we developed in order to capture melting temperatures both accurately and quickly. We propose a scheme that drastically improves the efficiency of Widom's particle insertion method by efficiently sampling cavities while calculating the integrals providing the chemical potentials of a physical system. This idea enables us to calculate chemical potentials of liquids directly from first-principles without the help of any reference system, which is necessary in the commonly used thermodynamic integration method. As an example, we apply our scheme, combined with the density functional formalism, to the calculation of the chemical potential of liquid copper. The calculated chemical potential is further used to locate the melting temperature. The calculated results closely agree with experiments. We propose the small-cell coexistence method based on the statistical analysis of small-size coexistence MD simulations. It eliminates the risk of a metastable superheated solid in the fast-heating method, while also significantly reducing the computer cost relative to the traditional large-scale coexistence method. Using empirical potentials, we validate the method and systematically study the finite-size effect on the calculated melting points. The method converges to the exact result in the limit of a large system size. An accuracy within 100 K in melting temperature is usually achieved when the simulation contains more than 100 atoms. DFT examples of Tantalum, high-pressure Sodium, and ionic material NaCl are shown to demonstrate the accuracy and flexibility of the method in its practical applications. The method serves as a promising approach for large-scale automated material screening in which

  5. Aqueous systems and geothermal energy

    International Nuclear Information System (INIS)

    Significant unpublished results reported include: osmotic coefficients of KCl solutions vs. molality at 109 to 2010C; cadmium ion diffusivities in CaCl2 hydrous melts; a x-ray diffraction study of the uranyl complex in water; solubility of amorphous silica in aqueous NaNO3 solutions at 100 to 3000C; and corrosion of carbon steel by geothermal brine

  6. Aqueous chemistry of iodine

    International Nuclear Information System (INIS)

    The chemistry of iodine has been examined in aqueous solutions of pH 6 to 10 containing 2500 ppM boron as H3BO3 at temperatures up to 1500C using absorption spectrophotometry to identify and monitor the iodine species present. Kinetic rate constants for the disproportionation of the HOI intermediate, 3HOI= IO3- + 2I- + 3H+, have been measured as a function of pH even though no direct spectral evidence for HOI itself has been observed. An HOI partition coefficient >104 has been estimated; results of ionic strength tests are consistent with HOI being present as an uncharged triatomic species in solution. Redox and radiation effects on the aqueous iodine chemistry have also been described. 11 refs., 2 figs., 3 tabs

  7. Hydrophobic ionic liquids

    Science.gov (United States)

    Koch, Victor R.; Nanjundiah, Chenniah; Carlin, Richard T.

    1998-01-01

    Ionic liquids having improved properties for application in non-aqueous batteries, electrochemical capacitors, electroplating, catalysis and chemical separations are disclosed. Exemplary compounds have one of the following formulas: ##STR1## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, and R.sub.6 are either H; F; separate alkyl groups of from 1 to 4 carbon atoms, respectively, or joined together to constitute a unitary alkylene radical of from 2 to 4 carbon atoms forming a ring structure converging on N; or separate phenyl groups; and wherein the alkyl groups, alkylene radicals or phenyl groups may be substituted with electron withdrawing groups, preferably F--, Cl--, CF.sub.3 --, SF.sub.5 --, CF.sub.3 S--, (CF.sub.3).sub.2 CHS-- or (CF.sub.3).sub.3 CS--; and X.sup.- is a non-Lewis acid-containing polyatomic anion having a van der Waals volume exceeding 100 .ANG..sup.3.

  8. Acidic Ionic Liquids.

    Science.gov (United States)

    Amarasekara, Ananda S

    2016-05-25

    Ionic liquid with acidic properties is an important branch in the wide ionic liquid field and the aim of this article is to cover all aspects of these acidic ionic liquids, especially focusing on the developments in the last four years. The structural diversity and synthesis of acidic ionic liquids are discussed in the introduction sections of this review. In addition, an unambiguous classification system for various types of acidic ionic liquids is presented in the introduction. The physical properties including acidity, thermo-physical properties, ionic conductivity, spectroscopy, and computational studies on acidic ionic liquids are covered in the next sections. The final section provides a comprehensive review on applications of acidic ionic liquids in a wide array of fields including catalysis, CO2 fixation, ionogel, electrolyte, fuel-cell, membrane, biomass processing, biodiesel synthesis, desulfurization of gasoline/diesel, metal processing, and metal electrodeposition. PMID:27175515

  9. Acidic Ionic Liquids.

    Science.gov (United States)

    Amarasekara, Ananda S

    2016-05-25

    Ionic liquid with acidic properties is an important branch in the wide ionic liquid field and the aim of this article is to cover all aspects of these acidic ionic liquids, especially focusing on the developments in the last four years. The structural diversity and synthesis of acidic ionic liquids are discussed in the introduction sections of this review. In addition, an unambiguous classification system for various types of acidic ionic liquids is presented in the introduction. The physical properties including acidity, thermo-physical properties, ionic conductivity, spectroscopy, and computational studies on acidic ionic liquids are covered in the next sections. The final section provides a comprehensive review on applications of acidic ionic liquids in a wide array of fields including catalysis, CO2 fixation, ionogel, electrolyte, fuel-cell, membrane, biomass processing, biodiesel synthesis, desulfurization of gasoline/diesel, metal processing, and metal electrodeposition.

  10. Synthesis and Characterization of Ammonium-, Pyridinium-, and Pyrrolidinium-Based Sulfonamido Functionalized Ionic Liquids

    DEFF Research Database (Denmark)

    Shunmugavel, Saravanamurugan; Fehrmann, Rasmus; Riisager, Anders

    2012-01-01

    New homologous ammonium-, pyridinium-, and pyrrolidinium-based sulfonamido functionalized ionic liquids have been synthesized in two steps using monoethanolamine, methanesulfonyl chloride, and tosyl chloride as precursors with ethanol as solvent. Attempts to synthesize dual amino functionalized...... ionic liquid containing both a primary and a secondary amine group in the same ionic liquid are also reported. All functionalized ionic liquids were characterized by 1H and 13C NMR. Melting point and thermal stability of the functionalized ionic liquids were measured by differential scanning calorimetry...

  11. Periodicity and map for discovery of new ionic liquids

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Suojiang

    2006-01-01

    [1]Trohalaki,S.,Pachter,R.,Drake,G.W.,Hawkins,T.,Quantitative structure-property relationships for melting points and densities of ionic liquids,Energy & Fuels,2005,19:279-284.[2]Holbery,J.D.,Seddon,K.R.,The phase behavior of 1-alkyl-3-methylimidazolium tetrafluoroborates,ionic liquids and ionic liquid crystals,J.Chem.Soc.Dalton Trans.,1999,13:2133-2139.[3]Katritzky,A.R.,Lomaka,A.,Petrukhin,R.et al.,QSPR correlation of the melting point for pyridinium bromides,potential ionic liquids,J.Chem.Inf.Comput.Sci.,2002,42:71-74.[4]Katritzky,A.R.,Jain,R.,Lomaka,A.et al.,Correlation of the melting points of potential ionic liquids (imidazolium bromides and benzimidazolium bromides) using the CODESSA program,J.Chem.Inf.Comput.Sci.,2002,42:225-231.[5]Eike,D.M.,Brennecke,J.F.,Maginn,E.J.,Predicting melting points of quaternary ammonium ionic liquids,Green Chemistry,2003,5:323-328.[6]Dupont,J.,Souza,R.F.,Suarez,A.Z.,Ionic liquid (molten salt) phase organometallic catalysis,J.Chem.Rev.,2002,102:3667-3692.[7]Turner,E.A.,Pye,C.C.,Singer,R.D.,Use of ab initio calculations toward the rational design of room temperature ionic liquids,J.Phys.Chem.A,2003,107(13):2277-2288.[8]Morrow,T.I.,Maginn,E.J.,Molecular dynamics study of the ionic liquid 1-n-butyl-3-methylimidazolium hexafluorophosphate,J.Phys.Chem.B,2002,106:12807-12813.[9]Cadena,C.,Antony,J.L.,Shah,J.K.et al.,Why is CO2 so soluble in imidazolium-based ionic liquids? J.Am.Chem.Soc.,2004,126(16):5300-5308.[10]Liu,Z.,Huang,S.,Wang,W.,A refined force field for molecular simulation of imidazolium-based ionic liquids,J.Phys.Chem.B,2004,108(34):12978-12989.[11]Earle,M.J,Seddon,K.R.,Ionic liquids,green solvents for the future,Pure Appl.Chem.,2000,72(7):1391-1398.[12]Mendeleev on periodicity:I and II,http://www.rod.beavon.clara.net/periodic1.htm[13]Hoffmann,R.,Building bridges between inorganic and organic chemistry,Angew.Chem.Int.Ed.Engl.,1982,21(10):711-800.

  12. Temperature-controlled ionic liquid dispersive liquid phase microextraction combined with ultra-high-pressure liquid chromatography for the rapid determination of triclosan,triclocarban and methyl-triclosan in aqueous samples

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    As extraction solvents,ionic liquids have green characteristics.In this study,an environmentally benign analytical method termed temperature-controlled ionic liquid dispersive liquid phase microextraction (TIL-DLME) combined with ultra-highpressure liquid chromatography (UHPLC)-tunable ultraviolet detection (TUV) was developed for the pre-concentration and determination of triclosan (TCS),triclocarban (TCC) and methyl-triclosan (M-TCS) in water samples.Significant parameters that may affect extraction efficiencies were examined and optimized,including the types and amount of ionic liquids,volume of the diluent,heating temperature,cooling time,salt effect and pH value.Under the optimum conditions,linearity of the method was observed in the ranges of 0.0100-100 μgL-1 for TCS and M-TCS,and 0.00500-50.0 μgL-1 for TCC with correlation coefficients (r2) > 0.9903.The limits of detection (LODs) ranged from 1.15 to 5.33 ngL-1.TCS in domestic water and TCC in reclaimed water were detected at the concentrations of 1.01 and 0.126 μgL-1,respectively.The spiked recoveries of the three target compounds in reclaimed water,irrigating water,waste water and domestic water samples were obtained in the ranges of 68.4%-71.9%,61.6%-87.8%,58.9%-74.9% and 64.9%-92.4%,respectively.Compared with the previous dispersive liquid-liquid microextraction method (DLLME) about the determination of TCS,TCC and M-TCS,this method is not only more environmentally friendly but also more sensitive.

  13. CPE OF URANIUM (VI USING IONIC LIQUID

    Directory of Open Access Journals (Sweden)

    SANAA NAÏT-TAHAR

    2016-07-01

    Full Text Available Cloud point extraction (CPE was used to extract uranium (VI from an aqueous solution in acetate media. The methodology used is based on the formation of uranyl-ionic liquid (I complexes and uranyl-D2EHPA soluble in a micellar phase of non-ionic surfactant (Triton X-100. The uranium (VI complexes are then extracted into the surfactant-rich phase at ambient temperature. The ionic liquid (IL used as a chelating agent was synthesized and characterized in this study. It is composed of N-butyl N’-triethoxy methyl imidazolium cation and diethylhexylphosphate (D2EHPA-H as anion. The effect of the IL on the extraction efficiency was studied in presence and in absence of IL’s cation in acetate medium.

  14. Thallium Transfer from Hydrochloric Acid Media into Pure Ionic Liquids.

    Science.gov (United States)

    Tereshatov, Evgeny E; Boltoeva, Maria Yu; Mazan, Valerie; Volia, Merinda F; Folden, Charles M

    2016-03-10

    Pure hydrophobic ionic liquids are known to extract metallic species from aqueous solutions. In this work we have systematically investigated thallium (Tl) extraction from aqueous hydrochloric acid (HCl) solutions into six pure fluorinated ionic liquids, namely imidazolium- and pyrrolidinium-based ionic liquids with bis(trifluoromethanesulfonyl)imide and bis(fluorosulfonyl)-imide anions. The dependence of the Tl extraction efficiency on the structure and composition of the ionic liquid ions, metal oxidation state, and initial metal and aqueous acid concentrations have been studied. Tl concentrations were on the order of picomolar (analyzed using radioactive tracers) and millimolar (analyzed using inductively coupled plasma mass spectrometry). The extraction of the cationic thallium species Tl(+) is higher for ionic liquids with more hydrophilic cations, while for the TlX(z)(3-z) anionic species (where X = Cl(-) and/or Br(-)), the extraction efficiency is greater for ionic liquids with more hydrophobic cations. The highest distribution value of Tl(III) was approximately 2000. An improved mathematical model based on ion exchange and ion pair formation mechanisms has been developed to describe the coextraction of two different anionic species, and the relative contributions of each mechanism have been determined. PMID:26769597

  15. The ionic product of water in concentrated tetramethylammonium chloride solutions.

    Science.gov (United States)

    Sipos, P; Bódi, I; May, P M; Hefter, G T

    1997-04-01

    The ionic product of water, pK(w) = - log[H(+)][OH(-)] has been determined in aqueous solutions of tetramethylammonium chloride over the concentration range of 0.1-5.5 M at 25 degrees C using high-precision glass electrode potentiometric titrations. pK(w) data relating to aqueous potassium and sodium chlorides at ionic strengths up to 5 M are markedly lower than the tetramethylammonium chloride results. These differences are almost certainly due to weak associations between potassium and (especially) sodium and hydroxide ions.

  16. A peroxotungstate-ionic liquid brush assembly: an efficient and reusable catalyst for selectively oxidizing sulfides with aqueous H{sub 2}O{sub 2} solution in neat water

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Xianying; Ma, Wenjuan; Ou, Hui; Han, Xiaoyan; Lu, Congmin; Chen, Yan; Wei, Junfa, E-mail: shixy@snnu.edu.cn, E-mail: weijf@snnu.edu.cn [School of Chemistry and Chemical Engineering, Shaanxi Normal University and Key Laboratory for Macromolecular Science of Shaanxi Province, Xian (China)

    2012-08-15

    An efficient and reusable heterogeneous catalytic assembly of peroxotungstate held in a ionic liquid (IL) brush was synthesized and an environmentally-friendly procedure was developed for selective oxidation of sulfides at room temperature using 30 wt.% hydrogen peroxide as the terminal oxidant and water as a sole solvent. No organic co-solvent or other additive was needed. A 1.5-2.0 mol% (based on W atom) loading catalyst was found to be sufficient for a smooth and clean reaction. Both aliphatic and aromatic sulfides were efficiently and selectively transformed into their respective sulfoxides or sulfones by simply controlling of equivalents of hydrogen peroxide. In addition to the high catalytic activity, the catalyst exhibits excellent chemoselectivity. Sensitive functional groups, such as double bond and hydroxyl, remained under the oxidation conditions the reaction even with an excess hydrogen peroxide. The catalyst was easily recovered (via simple filtration) and reused at least eight times without a noticeable loss of activity. (author)

  17. First Binary Mixture Ionic Liquids Containing EMIMBr and IM

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A new series of binary mixture ionic liquids comprising 1-ethyl-3-methylimidozaliumbromide (EMIMBr) and imidazole (IM) have been synthesized. The melting points of the ionicliquids vary with the different content of IM while they still keep satisfactory conductivity andviscosity. According to the analysis of its phase diagram, the eutectic point is about 16.5℃ withthe mass percentage of IM 29%.

  18. Non-Aqueous Capillary Electrophoresis

    Science.gov (United States)

    Szumski, Michał; Buszewski, Bogusław

    Non-aqueous capillary electrophoresis and capillary electrochromatography are special variants of these techniques. Here, organic solvents or their mixtures with or without dissolved electrolytes are used as separation buffer or mobile phase, respectively. The most important features of non-aqueous systems are: better solubility of more hydrophobic ionic substances (many natural products) than in water, much less current and Joule heating allows for using highly concentrated buffers and/or larger capillary internal diameters, polar interactions are enhanced in organic solvents which is often highly advantageous in chiral separation systems. This chapter presents most frequently used solvents, their properties, as well as shows pH* scale which is often used in non-aqueous systems.

  19. Influence of the ionic liquid cation on the solvent extraction of trivalent rare-earth ions by mixtures of Cyanex 923 and ionic liquids.

    Science.gov (United States)

    Rout, Alok; Binnemans, Koen

    2015-01-21

    Trivalent rare-earth ions were extracted from nitric acid medium by the neutral phosphine oxide extractant Cyanex 923 into ionic liquid phases containing the bis(trifluoromethylsulfonyl)imide anion. Five different cations were considered: 1-butyl-3-methylimidazolium, 1-decyl-3-methylimidazolium, methyltributylammonium, methyltrioctylammonium and trihexyl(tetradecyl)phosphonium. The extraction behavior of neodymium(iii) was investigated as a function of various parameters: pH, extractant concentration, concentration of the neodymium(iii) ion in the aqueous feed and concentration of the salting-out agent. The loading capacity of the ionic liquid phase was studied. The extraction efficiency increased with increasing pH of the aqueous feed solution. The extraction occurred for all ionic liquids via an ion-exchange mechanism and the extraction efficiency could be related to the solubility of the ionic liquid cation in the aqueous phase: high distribution ratios for hydrophilic cations and low ones for hydrophobic cations. Addition of nitrate ions to the aqueous phase resulted in an increase in extraction efficiency for ionic liquids with hydrophobic cations due to extraction of neutral complexes. Neodymium(iii) could be stripped from the ionic liquid phase by 0.5-1.0 M nitric acid solutions and the extracting phase could be reused. The extractability of other rare earths present in the mixture was compared for the five ionic liquids.

  20. Ionic liquid tunes microemulsion curvature.

    Science.gov (United States)

    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. PMID:19161325

  1. Melting of Transition Metals

    Energy Technology Data Exchange (ETDEWEB)

    Ross, M; Japel, S; Boehler, R

    2005-04-11

    We review the transition melting studies carried out at Mainz, and describe a recently developed model used to explain that the relatively low melting slopes are due to the partially filled d-bands, and the persistence of the pressure induced s-d transition. The basic tenets of the model have now been reconfirmed by new measurements for Cu and Ni. The measurements show that Cu which has a filled 3d-band, has a melt slope that is about 2.5 greater than its neighbor Ni. In the case of Mo, the apparent discrepancy of DAC melting measurements with shock melting can be explained by accounting for the change in melt slope due to the bcc-cp transition observed in the shock studies. The Fe melt curve is revisited. The possible relevance of the Jahn-Teller effect and recently observed transition metal melts with Icosahedral Short-Range Order (ISRO) is discussed.

  2. Functional ionic liquids; Funktionelle ionische Fluessigkeiten

    Energy Technology Data Exchange (ETDEWEB)

    Baecker, Tobias

    2012-07-01

    In the thesis at hand, new functional ionic liquids were investigated. Main focus was attended to their structure property relations and the structural features leading to a decrease of the melting point. New compounds of the type 1-butyl-3-methylimidazolium tris(N,Ndialkyldithiocarbamato) uranylate with variously substituated dithiocarbamato ligands were synthesized and characterized. Ligands with asymmetrical substitution pattern proved to be most suitable for ionic liquid formation. The single-crystal X-ray structures revealed the interactions in the solid state. Here, the first spectroscopic investigation of the U-S bond in sulfur donated uranyl complexes, up to now only observed in single-crystal X-ray structures, is presented, and the participation of the uranium f-orbitals is shown by theoretical calculations. Electrochemical investigations showed the accessibility of the respective U{sup V}O{sub 2}{sup +} compounds. As well, ionic liquids with [FeCl{sub 4}]{sup -} and [Cl{sub 3}FeOFeCl{sub 3}]{sup 2-} as anion were synthesized. Both of these anions contain high-spin Fe(III) centres in distorted tetrahedral environment, but exhibit different magnetic behaviour. The tetrachloroferrates show the usual paramagnetism, the m-oxobis(trichloroferrate) exhibits unexpectedly strong antiferromagnetic coupling, as was observed by NMR experiments and susceptibility measurements. To investigate structure-property relations in functionalized ionic liquids, a set of protic, primary alkylammonium and aprotic, quarternary trimethylalkylammonium based ionic liquids was synthesized, and characterized. The length of the alkyl chain was systematically varied, and all compounds were synthesized with and without hydroxyl group, as well as formate and bis(triflyl)amide salts, aiming at getting insight into the influence of the different structure parts on the respective ionic liquid's properties.

  3. Cluster Morphology-Polymer Dynamics Correlations in Sulfonated Polystyrene Melts: Computational Study

    Science.gov (United States)

    Agrawal, Anupriya; Perahia, Dvora; Grest, Gary S.

    2016-04-01

    Reaching exceptionally long times up to 500 ns in equilibrium and nonequilibrium molecular dynamics simulations studies, we have attained a fundamental molecular understanding of the correlation of ionomer clusters structure and multiscale dynamics, providing new insight into one critical, long-standing challenge in ionic polymer physics. The cluster structure in melts of sulfonated polystyrene with Na+ and Mg2 + counterions are resolved and correlated with the dynamics on multiple length and time scales extracted from measurements of the dynamic structure factor and shear rheology. We find that as the morphology of the ionic clusters changes from ladderlike for Na+ to disordered structures for Mg2 + , the dynamic structure factor is affected on the length scale corresponding to the ionic clusters. Rheology studies show that the viscosity for Mg2 + melts is higher than for Na+ ones for all shear rates, which is well correlated with the larger ionic clusters' size for the Mg2 + melts.

  4. A view of aqueous electrochemical carbon dioxide reduction to formate at indium electrodes, and the reversible electrodeposition of silver in ionic liquids through the lens of fundamental surface science

    Science.gov (United States)

    Detweiler, Zachary M.

    Two systems were studied using in situ measurement techniques, demonstrating the importance of creative experimental design. The electroreduction of CO2 at heterogeneous indium electrodes in aqueous solution was analyzed by cyclic voltammetry. Bulk electrolyses showed that increased indium oxide presence prior to electrolysis improved the Faradaic efficiency of CO 2 reduction to formate in 0.5 M K2SO2 aqueous solutions at a pH of 4.4. In order to more accurately assign speciation at the electrode surface ex situ O2 and H2O dosing of metallic indium under UHV was studied with XPS, HREELS and TPD. Ambient pressure XPS showed that the ratio of oxide to hydroxide at the indium interface is strongly dependent on the partial pressure of water; decreasing as P(H2O) increases. Using this information, a qualitative picture of the indium interface could be generated. In situ ATR-FTIR with an indium thin film as the working electrode showed that bulk oxide quickly reduces with applied potential, but an interfacial oxide is still present at high reductive overpotential. Additionally, an adsorbed carbonate at the thin film interface was observed upon introducing CO 2 to the cell. The implication of a surface bound carbonate as the CO 2 reduction intermediate draws on a mechanism that has not previously been discussed in the electrochemical reduction of CO2. The previous study of this mechanism from Ficscher-Tropsch literature helps to predict the further reduced products found at more electropositive metals, such as copper or magnesium, the latter of which is described here. Additionaly described here is a series of ILs that were employed as electrolyte for reversible silver deposition. BMIM N(TfO)2 was found to be the most promising of those studied, intrinsically giving a more uniform deposit that was bright and reversible. Deposit formation was studied using SEM and EDX as a function of deposition potential and deposition time. In situ reflectometry was employed to get a

  5. Ionic Liquids in Tribology

    Directory of Open Access Journals (Sweden)

    Ichiro Minami

    2009-06-01

    Full Text Available Current research on room-temperature ionic liquids as lubricants is described. Ionic liquids possess excellent properties such as non-volatility, non-flammability, and thermo-oxidative stability. The potential use of ionic liquids as lubricants was first proposed in 2001 and approximately 70 articles pertaining to fundamental research on ionic liquids have been published through May 2009. A large majority of the cations examined in this area are derived from 1,3-dialkylimidazolium, with a higher alkyl group on the imidazolium cation being beneficial for good lubrication, while it reduces the thermo-oxidative stability. Hydrophobic anions provide both good lubricity and significant thermo-oxidative stability. The anions decompose through a tribochemical reaction to generate metal fluoride on the rubbed surface. Additive technology to improve lubricity is also explained. An introduction to tribology as an interdisciplinary field of lubrication is also provided.

  6. Model of interfacial melting

    DEFF Research Database (Denmark)

    Mouritsen, Ole G.; Zuckermann, Martin J.

    1987-01-01

    A two-dimensional model is proposed to describe systems with phase transitions which take place in terms of crystalline as well as internal degrees of freedom. Computer simulation of the model shows that the interplay between the two sets of degrees of freedom permits observation of grain-boundar......-boundary formation and interfacial melting, a nonequilibrium process by which the system melts at the boundaries of a polycrystalline domain structure. Lipid membranes are candidates for systems with pronounced interfacial melting behavior....

  7. Preparation and Characterization of New Type Ionic Liquids

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A new type of ionic liquids containing cation of diacetone acrylamide [or N-(1,1- bismethyl-3-oxo-butyl)acrylamide] and anions such as CH3COO-(Ac), CF3COO(-(TF), BF4-(BF), PF6-(PF), HSO4-(SO) and Cl-(Cl) were prepared by normal neutralization.The obtained ionic liquids were identified by FT-IR and 1H NMR spectroscopy.However, their properties such as melting point, conductivity, viscosity etc.were determined.

  8. Task-specific ionic liquid for solubilizing metal oxides.

    Science.gov (United States)

    Nockemann, Peter; Thijs, Ben; Pittois, Stijn; Thoen, Jan; Glorieux, Christ; Van Hecke, Kristof; Van Meervelt, Luc; Kirchner, Barbara; Binnemans, Koen

    2006-10-26

    Protonated betaine bis(trifluoromethylsulfonyl)imide is an ionic liquid with the ability to dissolve large quantities of metal oxides. This metal-solubilizing power is selective. Soluble are oxides of the trivalent rare earths, uranium(VI) oxide, zinc(II) oxide, cadmium(II) oxide, mercury(II) oxide, nickel(II) oxide, copper(II) oxide, palladium(II) oxide, lead(II) oxide, manganese(II) oxide, and silver(I) oxide. Insoluble or very poorly soluble are iron(III), manganese(IV), and cobalt oxides, as well as aluminum oxide and silicon dioxide. The metals can be stripped from the ionic liquid by treatment of the ionic liquid with an acidic aqueous solution. After transfer of the metal ions to the aqueous phase, the ionic liquid can be recycled for reuse. Betainium bis(trifluoromethylsulfonyl)imide forms one phase with water at high temperatures, whereas phase separation occurs below 55.5 degrees C (temperature switch behavior). The mixtures of the ionic liquid with water also show a pH-dependent phase behavior: two phases occur at low pH, whereas one phase is present under neutral or alkaline conditions. The structures, the energetics, and the charge distribution of the betaine cation and the bis(trifluoromethylsulfonyl)imide anion, as well as the cation-anion pairs, were studied by density functional theory calculations. PMID:17048916

  9. Conductivity of Oxalic Acid in Aqueous Solution at Low Concentration

    Institute of Scientific and Technical Information of China (English)

    倪良; 韩世钧

    2005-01-01

    Oxalic acid is a weak and unsymmetrical bi-basic acid. There exist dissociation and association equilibria among the species in aqueous solution. The molar conductivity of the solution is the sum of the ionic contributions.Based on this idea, a new prediction equation of ionic conductivity was proposed at low concentration. The molar conductivities of the solution and its relevant ions were calculated respectively. The results obtained were in good agreement with those from experiments and the Quint-Viallard equation.

  10. Hg⁰ removal from flue gas by ionic liquid/H₂O₂.

    Science.gov (United States)

    Cheng, Guangwen; Bai, Bofeng; Zhang, Qiang; Cai, Ming

    2014-09-15

    1-Alkyl-3-methylimidazolium chloride ionic liquids ([Cnmim] Cl, n=4, 6, 8) were prepared. The ionic liquid was then mixed with hydrogen peroxide (H2O2) to form an absorbent. The Hg(0) removal performance of the absorbent was investigated in a gas/liquid scrubber using simulated flue gas. It was found that the ionic liquid/H2O2 mixture was an excellent absorbent and could be used to remove Hg(0) from flue gas. When the mass ratio of H2O2 to ionic liquid was 0.5, the absorbent showed high Hg(0) removal efficiency (up to 98%). The Hg(0) removal efficiency usually increased with the absorption temperature, while decreased with the increase of alkyl chain length in ionic liquid molecule. The Hg(0) removal mechanism involved with Hg(0) oxidation by H2O2 and Hg(2+) transfer from aqueous phase to ionic liquid phase.

  11. Ionic liquids: the link to high-temperature molten salts?

    Science.gov (United States)

    El Abedin, Sherif Zein; Endres, Frank

    2007-11-01

    Due to their wide thermal windows, ionic liquids can be regarded as the missing link between aqueous/organic solutions and high-temperature molten salts. They can be employed efficiently for the coating of other metals with thin layers of tantalum, aluminum, and presumably many others at reasonable temperatures by electrochemical means. The development of ionic liquids, especially air and water stable ones, has opened the door for the electrodeposition of reactive elements such as, for example, Al, Ta, and Si, which in the past were only accessible using high-temperature molten salts or, in part, organic solvents. PMID:17521159

  12. Hydrolysis and Partial Recycling of a Chloroaluminate Ionic Liquid

    Directory of Open Access Journals (Sweden)

    Li-Sheng Wang

    2007-06-01

    Full Text Available Hydrolysis of the ionic liquid Et3NHCl-2AlCl3 and a process for recycling thetriethylamine were studied. When the hydrolysis was carried out at a relatively hightemperature, the released HCl could be absorbed more easily. With addition of sodiumhydroxide to the aqueous hydrolysis solution, a feasible process for recycling triethylaminewas developed, involving first distillation of triethylamine, followed by filtration of thealuminium hydroxide. The yield of recovered triethylamine was about 95%. Thetriethylhydrogenammonium chloride prepared from the recycled triethylamine was of goodpurity and could be reused to synthesize new chloroaluminate ionic liquids.

  13. A new approach for freezing of aqueous solutions under active control of the nucleation temperature.

    Science.gov (United States)

    Petersen, Ansgar; Schneider, Hendrik; Rau, Guenter; Glasmacher, Birgit

    2006-10-01

    An experimental setup for controlled freezing of aqueous solutions is introduced. The special feature is a mechanism to actively control the nucleation temperature via electrofreezing: an ice nucleus generated at a platinum electrode by the application of an electric high voltage pulse initiates the crystallization of the sample. Using electrofreezing, the nucleation temperature in pure water can be precisely adjusted to a desired value over the whole temperature range between a maximum temperature Tn(max) close to the melting point and the temperature of spontaneous nucleation. However, the presence of additives can inhibit the nucleus formation. The influence of hydroxyethylstarch (HES), glucose, glycerol, additives commonly used in cryobiology, and NaCl on Tn(max) were investigated. While the decrease showed to be moderate for the non-ionic additives, the hindrance of nucleation by ionic NaCl makes the direct application of electrofreezing in solutions with physiological salt concentrations impossible. Therefore, in the multi-sample freezing device presented in this paper, the ice nucleus is produced in a separate volume of pure water inside an electrode cap. This way, the nucleus formation becomes independent of the sample composition. Using electrofreezing rather than conventional seeding methods allows automated freezing of many samples under equal conditions. Experiments performed with model solutions show the reliability and repeatability of this method to start crystallization in the test samples at different specified temperatures. The setup was designed to freeze samples of small volume for basic investigations in the field of cryopreservation and freeze-drying, but the mode of operation might be interesting for many other applications where a controlled nucleation of aqueous solutions is of importance. PMID:16887112

  14. Elaboration and characterization of hybrid lithium-ion conducting membranes for aqueous lithium-air batteries

    OpenAIRE

    Lancel, Gilles

    2016-01-01

    Aqueous lithium-air batteries could be a revolution in energy storage, but the main limitation is the use of a thick glass-ceramic lithium ionic conductor to isolate the metallic lithium from the aqueous electrolyte. This makes the system more fragile, limits its cyclability and increases ohmic resistance. The aim of this work is to replace the glass-ceramic by a hybrid membrane made by electrospinning, which combines water tightness, flexibility and lithium-ions conductivity. The ionic condu...

  15. Electrowinning of UO2 from ionic liquid medium

    International Nuclear Information System (INIS)

    This paper deals with the dissolution of UO3 and UO2 by chlorination reaction in bmimCI medium and recovery of uranium by electrodeposition. The electrochemical behavior of U(VI) in ionic liquid was investigated by cyclic voltammetry as a prelude to electrodeposition. About 100 mg of uranium oxide (UO3 and UO2) (average particle size 10 mm) was mixed with 20 g of bmimCI ionic liquid, which is taken in a leak tight electrochemical cell. Dry chlorine gas was bubbled through the melt at the flow rate of 5ml/min, at 353 K, for a pre-determined time. The amount of uranium dissolved in the melt was studied by measuring the absorbance of U(VI) as well as by ICP-OES measurements

  16. On Barium Oxide Solubility in Barium-Containing Chloride Melts

    Science.gov (United States)

    Nikolaeva, Elena V.; Zakiryanova, Irina D.; Bovet, Andrey L.; Korzun, Iraida V.

    2016-08-01

    Oxide solubility in chloride melts depends on temperature and composition of molten solvent. The solubility of barium oxide in the solvents with barium chloride content is essentially higher than that in molten alkali chlorides. Spectral data demonstrate the existence of oxychloride ionic groupings in such melts. This work presents the results of the BaO solubility in two molten BaCl2-NaCl systems with different barium chloride content. The received data together with earlier published results revealed the main regularities of BaO solubility in molten BaO-BaCl2-MCl systems.

  17. Preparation of diffusion coatings in ion-electron melts

    Institute of Scientific and Technical Information of China (English)

    Anfinogenov; A.; I.; Chebykin; V.; V.; Chernov; Ya.; B.

    2005-01-01

    A procedure of Ni, Cr, Mn, Co, and Mo (Me) transfer onto iron substrate in ionic-electronic melts LiCl-Li, CaCl2-Ca, and BaCl2-Ba was elaborated and the transport processes were studied. The saturated vapor pressure of these ionic-electronic melts is as low as enabled working at atmosphere pressure in an inert media up to 1000 ℃.Armco iron was used as a substrate because it practically does not interact with lithium, calcium, and barium. The metals-diffusants were put into the melts in the form of a powder. The complete saturation of the melts with lithium, calcium, and barium was ensured by a preceding contact of a molten salt with an excess of Li, Ca, or Ba before loading of iron.The reactions take place despite the metals and iron were separated from each other by the molten salt. The quantity of the metals transfered was determined by the change in mass before and after experiments, by microprobe analysis, and x-raying of the iron surface layer. The experiments were carried out at 900, 950 and 1000℃ during 5, 10, 15 and 20 hours.At the first stage of the process the formation of the ionic-electronic melt occurs. For example, dissolution of calcium in the case of the system CaCl2-Ca is mainly proceeded in the form of one-valent cations: Ca + Ca2+()Ca+. As soon as the metal-diffusance is immersed into the melt, its dissolution in the form of negative ions takes place: Me + Ca+() Me-+ Ca2+. In the vicinity of the iron substrate the last equilibrium will shift to the left generating a solid solution or intermetallide. The thickness of the diffusion layer rises as the temperature and saturation time increase. The obtained coverings were 20-60 (m thick,and their surface layer contained 15%-80% (mass fraction) of the metal-diffusance.Both the composition of the melt and the procedure of the coverings preparation in ionic-electronic melts have been patented (Patent RU2058422, 1996, pr. 30.09.93).

  18. CALCULATING ACTIVITY COEFFICIENTS OF ELECTROLYTE AQUEOUS SOLUTION WITH PERTURBATION THEORY-BASED EQUATION OF STATE%用微扰理论状态方程计算电解质水溶液的活度系数

    Institute of Scientific and Technical Information of China (English)

    李春喜; 宋红燕; 李以圭; 陆九芳

    2001-01-01

    An equation of state for electrolyte aqueous solution is developed by treating the ion-ion electrostatic and ion-solvent molecule interactions with primitive MSA and perturbation theory, respectively. The effect of the dielectric constant on the ionic chemical potential and the calculation accuracy of ionic mean activity coefficients for 2∶1 and 1∶1 type halide aqueous solution are discussed.By taking ionic Pauling diameter as ionic hard sphere diameter for anions and treating the cation hard sphere diameter as ionic strength dependent, the equation can be used to calculate ionic activity coefficients in the moderate concentration range with good accuracy.

  19. Osmotic Pressure of Aqueous Chondroitin Sulfate Solution: A Molecular Modeling Investigation

    OpenAIRE

    Bathe, Mark; Rutledge, Gregory C.; Grodzinsky, Alan J.; TIDOR, BRUCE

    2005-01-01

    The osmotic pressure of chondroitin sulfate (CS) solution in contact with an aqueous 1:1 salt reservoir of fixed ionic strength is studied using a recently developed coarse-grained molecular model. The effects of sulfation type (4- vs. 6-sulfation), sulfation pattern (statistical distribution of sulfate groups along a chain), ionic strength, CS intrinsic stiffness, and steric interactions on CS osmotic pressure are investigated. At physiological ionic strength (0.15 M NaCl), the sulfation typ...

  20. Antimicrobial Ionic Liquids with Fumarate Anion

    Directory of Open Access Journals (Sweden)

    Biyan He

    2013-01-01

    Full Text Available The shortage of new antimicrobial drugs and increasing resistance of microbe to antimicrobial agents have been of some concern. The formulation studies of new antibacterial and antifungal agents have been an active research field. Ionic liquids are known as designed liquids with controllable physical/chemical/biological properties and specific functions, which have been attracting considerable interest over recent years. However, no attention has been made towards the preparation of ionic liquids with antimicrobial activities. In this paper, a new class of ionic liquids (ILs with fumarate anion was synthesized by neutralization of aqueous 1-butyl-3-methylimidazolium hydroxide with equimolar monoester fumarate and characterized using NMR and thermal gravimetric analysis. The ILs are soluble in water and polar organic solvents and also soluble in the common ILs. The antimicrobial activities of the ILs are more active than commercially available potassium sorbate and are greatly affected by the alkyl chain length. The significant antimicrobial properties observed in this research suggest that the ILs may have potential applications in the modern biotechnology.

  1. Ionic liquids in microemulsions – a concept to extend the conventional thermal stability range of microemulsions

    OpenAIRE

    Zech, Oliver

    2010-01-01

    Ionic liquids (ILs), which are defined as salts with a melting point below 100°C are often considered as future solvents for catalysis, chemical reactions, extractions and electrochemical purposes. Apart from these classical applications, ILs have also gained interest in classical colloid and surface chemistry. The formation of amphiphilic association structures in and with ionic liquids, such as micelles, vesicles, microemulsions and liquid crystalline phases have been described in literatur...

  2. Synthesis of New Energetic Materials and Ionic Liquids Derived from Metronidazole

    OpenAIRE

    Romero, Miguel A.

    2016-01-01

    Simple and efficient synthetic procedures were established for the preparation of new energetic covalent compounds, salts, and protonated ionic liquids based on the readily available antimicrobial agent metronidazole. Some of these materials exhibit the desirable properties of energetic materials and energetic ionic liquids, such as low vapor pressure, low melting point, good chemical and thermal stability, and high energetic content. For each of the relevant compounds prepared, thermal stabi...

  3. Reaction of uranium dioxide with copper-containing chloride melts

    International Nuclear Information System (INIS)

    Cermet composition materials consisting of metallic copper and uranium dioxide can be used for manufacturing fuel rods of nuclear power reactors. Reprocessing of such irradiated fuel of dispersive type can be done employing non-aqueous pyrochemical methods and developing such technology requires information on interaction of uranium dioxide with chloride melts containing copper ions

  4. Signatures of nonthermal melting

    Directory of Open Access Journals (Sweden)

    Tobias Zier

    2015-09-01

    Full Text Available Intense ultrashort laser pulses can melt crystals in less than a picosecond but, in spite of over thirty years of active research, for many materials it is not known to what extent thermal and nonthermal microscopic processes cause this ultrafast phenomenon. Here, we perform ab-initio molecular-dynamics simulations of silicon on a laser-excited potential-energy surface, exclusively revealing nonthermal signatures of laser-induced melting. From our simulated atomic trajectories, we compute the decay of five structure factors and the time-dependent structure function. We demonstrate how these quantities provide criteria to distinguish predominantly nonthermal from thermal melting.

  5. Acrylate Functionalized Tetraalkylammonium Salts with Ionic Liquid Properties

    Directory of Open Access Journals (Sweden)

    Silvia Janietz

    2012-05-01

    Full Text Available Acrylate functionalized ionic liquids based on tetraalkylammonium salts with terminal acrylates- and methylacrylates were synthesized. Melting points and ionic conductivity of twenty compounds in six groups were determined. Within one group the effect of three different counterions was investigated and discussed. The groups differ in cationic structure elements because of their functional groups such as acrylate and methacrylate, alkyl residues at the nitrogen and number of quaternary ammonium atoms within the organic cation. The effect of these cationic structure elements has been examined concerning the compiled parameters with a view to qualifying them as components for solid state electrolytes. The newly synthesized ionic liquids were characterized by NMR and FTIR analysis. The exchange of halide ions like bromide as counter ions to weakly coordinating [PF6], [OTf] or [TFSI] reduces the melting points significantly and leads to an ion conductivity of about 10−4 S/cm at room temperature. In the case of the dicationic ionic liquid, an ion conductivity of about 10−3 S/cm was observed.

  6. Applications of functionalized ionic liquids

    Institute of Scientific and Technical Information of China (English)

    LI Xuehui; ZHAO Dongbin; FEI Zhaofu; WANG Lefu

    2006-01-01

    Recent developments of the synthesis and applications of functionalized ionic liquids(including dual-functionalized ionic liquids) have been highlighted in this review. Ionic liquids are attracting attention as alternative solvents in green chemistry, but as more functionalized ILs are prepared, a greater number of applications in increasingly diverse fields are found.

  7. Radiation chemistry of ionic liquids

    International Nuclear Information System (INIS)

    Ionic liquids are expected as a replacement of processing media for the nuclear fuel cycle. Therefore, an understanding of the interactions of ionizing radiations and photons with ionic liquids is strongly needed. However, the radiation chemistry of ionic liquids is still a relatively unexplored topic although there has been a significant increase in the number of researchers in the field recently. (author)

  8. Melting of sodium clusters

    CERN Document Server

    Reyes-Nava, J A; Beltran, M R; Michaelian, K

    2002-01-01

    Thermal stability properties and the melting-like transition of Na_n, n=13-147, clusters are studied through microcanonical molecular dynamics simulations. The metallic bonding in the sodium clusters is mimicked by a many-body Gupta potential based on the second moment approximation of a tight-binding Hamiltonian. The characteristics of the solid-to-liquid transition in the sodium clusters are analyzed by calculating physical quantities like caloric curves, heat capacities, and root-mean-square bond length fluctuations using simulation times of several nanoseconds. Distinct melting mechanisms are obtained for the sodium clusters in the size range investigated. The calculated melting temperatures show an irregular variation with the cluster size, in qualitative agreement with recent experimental results. However, the calculated melting point for the Na_55 cluster is about 40 % lower than the experimental value.

  9. Ionic smoke detectors

    CERN Document Server

    2002-01-01

    Ionic smoke detectors are products incorporating radioactive material. This article summarises the process for their commercialization and marketing, and how the activity is controlled, according to regulations establishing strict design and production requisites to guarantee the absence of radiological risk associated both with their use and their final handling as conventional waste. (Author)

  10. Ionic and Molecular Liquids

    DEFF Research Database (Denmark)

    Chaban, Vitaly V.; Prezhdo, Oleg

    2013-01-01

    Because of their outstanding versatility, room-temperature ionic liquids (RTILs) are utilized in an ever increasing number of novel and fascinating applications, making them the Holy Grail of modern materials science. In this Perspective, we address the fundamental research and prospective...

  11. Melt fracture revisited

    Energy Technology Data Exchange (ETDEWEB)

    Greenberg, J. M.

    2003-07-16

    In a previous paper the author and Demay advanced a model to explain the melt fracture instability observed when molten linear polymer melts are extruded in a capillary rheometer operating under the controlled condition that the inlet flow rate was held constant. The model postulated that the melts were a slightly compressible viscous fluid and allowed for slipping of the melt at the wall. The novel feature of that model was the use of an empirical switch law which governed the amount of wall slip. The model successfully accounted for the oscillatory behavior of the exit flow rate, typically referred to as the melt fracture instability, but did not simultaneously yield the fine scale spatial oscillations in the melt typically referred to as shark skin. In this note a new model is advanced which simultaneously explains the melt fracture instability and shark skin phenomena. The model postulates that the polymer is a slightly compressible linearly viscous fluid but assumes no slip boundary conditions at the capillary wall. In simple shear the shear stress {tau}and strain rate d are assumed to be related by d = F{tau} where F ranges between F{sub 2} and F{sub 1} > F{sub 2}. A strain rate dependent yield function is introduced and this function governs whether F evolves towards F{sub 2} or F{sub 1}. This model accounts for the empirical observation that at high shears polymers align and slide more easily than at low shears and explains both the melt fracture and shark skin phenomena.

  12. Modeling reactive geochemical transport of concentrated aqueous solutions

    Science.gov (United States)

    Zhang, Guoxiang; Zheng, Zuoping; Wan, Jiamin

    2005-02-01

    Aqueous solutions with ionic strength larger than 1 M are usually considered concentrated aqueous solutions. These solutions can be found in some natural systems and are also industrially produced and released into accessible natural environments, and as such, they pose a big environmental problem. Concentrated aqueous solutions have unique thermodynamic and physical properties. They are usually strongly acidic or strongly alkaline, with the ionic strength possibly reaching 30 M or higher. Chemical components in such solutions are incompletely dissociated. The thermodynamic activities of both ionic and molecular species in these solutions are determined by the ionic interactions. In geological media the problem is further complicated by the interactions between the solutions and sediments and rocks. The chemical composition of concentrated aqueous solutions when migrating through the geological media may be drastically altered by these strong fluid-rock interactions. To effectively model reactive transport of concentrated aqueous solutions, we must take into account the ionic interactions. For this purpose we substantially extended an existing reactive transport code, BIO-CORE2D©, by incorporating a Pitzer ion interaction model to calculate the ionic activity. In the present paper, the model and two test cases of the model are briefly introduced. We also simulate a laboratory column experiment in which the leakage of highly alkaline waste fluid stored at Hanford (a U.S. Department of Energy site, located in Washington State) was studied. Our simulation captures the measured pH evolution and indicates that all the reactions controlling the pH evolution, including cation exchanges and mineral dissolution/precipitation, are coupled.

  13. Chain and Ion Dynamics in Ionomer Melts

    Science.gov (United States)

    Register, Richard A.

    2003-03-01

    Ionomers contain a minor quantity of covalently-bound ionic sites, such as carboxylic or sulfonic acid salts, typically distributed randomly along the polymer backbone. Associations between these ionic groups greatly increase the melt viscosity and elasticity through the formation of a reversible network, where the ionic crosslinks gradually relax by a ``hopping" of ionic groups between aggregates. Because terminal relaxation of the chain requires an accumulation of many hops, the time scales for ion and chain motion differ by several orders of magnitude, so we employ mechanical rheometry to probe chain motion, and gauge ion motion through cation diffusion, by annealing for a preset interval and measuring the cation concentration profile through electron probe microanalysis or electron spin resonance spectroscopy. We have investigated both ethylene-methacrylic acid (E/MAA) ionomers, with a broad molecular weight distribution and substantial long-chain branching, as well as new linear-chain ionomers of narrow distribution based on lightly-sulfonated styrene-ethylene-butene (SSEB) terpolymers. Our E/MAA results support the ion-hopping mechanism, with similarly-large activation energies for terminal relaxation and cation diffusion. The choice of neutralizing metal cation has only a modest effect on the dynamics, though the terminal time increases exponentially with neutralization level. Unneutralized acid groups can accelerate the ion-hopping process by "plasticizing" the ionic aggregates. The model SSEB ionomers, which are noncrystallizable and have a low Tg, permit measurements over a much wider range of effective frequencies and are found to deviate substantially from time-temperature superposition, because the outermost portions of the polymer chains, which contain no ionic groups, relax with a smaller activation energy. Relaxation of these chain segments leads to a dilution of the entanglement network, and a plateau modulus below that for highly

  14. Electrodeposition from cationic cuprous organic complexes: Ionic liquids for high current density electroplating

    OpenAIRE

    Schaltin, Stijn; Brooks, Neil; Binnemans, Koen; Fransaer, Jan

    2011-01-01

    The electrochemical behavior of the low-melting copper salts [Cu(MeCN)(x)][Tf2N] and [Cu(PhCN)(x)][Tf2N] (x = 2-4), where MeCN is acetonitrile and PhCN is benzonitrile, is presented. In these compounds, the copper(I) ion is a main component of the ionic liquid cation. Consequently, the copper concentration is the highest achievable for an ionic liquid and this permits to obtain a good mass transport and high current densities for electrodeposition. The cathodic limit of the ionic liquid is th...

  15. Ionic imbalance induced self-propulsion of liquid metals

    Science.gov (United States)

    Zavabeti, Ali; Daeneke, Torben; Chrimes, Adam F.; O'Mullane, Anthony P.; Zhen Ou, Jian; Mitchell, Arnan; Khoshmanesh, Khashayar; Kalantar-Zadeh, Kourosh

    2016-08-01

    Components with self-propelling abilities are important building blocks of small autonomous systems and the characteristics of liquid metals are capable of fulfilling self-propulsion criteria. To date, there has been no exploration regarding the effect of electrolyte ionic content surrounding a liquid metal for symmetry breaking that generates motion. Here we show the controlled actuation of liquid metal droplets using only the ionic properties of the aqueous electrolyte. We demonstrate that pH or ionic concentration gradients across a liquid metal droplet induce both deformation and surface Marangoni flow. We show that the Lippmann dominated deformation results in maximum velocity for the self-propulsion of liquid metal droplets and illustrate several key applications, which take advantage of such electrolyte-induced motion. With this finding, it is possible to conceive the propulsion of small entities that are constructed and controlled entirely with fluids, progressing towards more advanced soft systems.

  16. Pressure-induced melting of micellar crystal

    DEFF Research Database (Denmark)

    Mortensen, K.; Schwahn, D.; Janssen, S.

    1993-01-01

    Aqueous solutions of triblock copolymers of poly(ethylene oxide) and poly(propylene oxide) aggregate at elevated temperatures into micelles which for polymer concentrations greater-than-or-equal-to 20% make a hard sphere crystallization to a cubic micellar crystal. Structural studies show...... that pressure improves the solvent quality of water, thus resulting in decomposition of the micelles and consequent melting of the micellar crystal. The combined pressure and temperature dependence reveals that in spite of the apparent increase of order on the 100 angstrom length scale upon increasing...

  17. Fluorination effects on the thermodynamic, thermophysical and surface properties of ionic liquids

    Science.gov (United States)

    Reis, P. M.; Carvalho, P. J.; Lopes-da-Silva, J. A.; Esperança, J. M. S. S.; Araújo, J. M. M.; Rebelo, L. P. N.; Freire, M. G.; Pereiro, A. B.

    2016-01-01

    This paper reports the thermal, thermodynamic, thermophysical and surface properties of eight ionic liquids with fluorinated alkyl side chain lengths equal or greater than four carbon atoms. Melting and decomposition temperatures were determined together with experimental densities, surface tensions, refractive indices, dynamic viscosities and ionic conductivities in a temperature interval ranging from 293.15 to 353.15 K. The surface properties of these fluorinated ionic liquids were discussed and several thermodynamic functions, as well as critical temperatures, were estimated. Coefficients of isobaric thermal expansion, molecular volumes and free volume effects were calculated from experimental values of density and refractive index and compared with previous data. Finally, Walden plots were used to evaluate the ionicity of the investigated ionic liquids.

  18. Functionalized ionic liquids. New agents for the extraction of actinides/lanthandies

    Energy Technology Data Exchange (ETDEWEB)

    Ouadi, A.; Billard, I.; Gaillard, C. [CNRS/IN2P3 and Univ. L. Pasteur, Strasbourg (France). Inst. de Recherches Subatomiques; Hesemann, P.; Gadenne, B.; Moreau, J. [CNRS UMR 5076, Heterochimie Moleculaire et Macromoleculaire, Lab. de Chimie Organometallique, Montpellier (France); Moutiers, G.; Mariet, C.; Labet, A.; Mekki, S. [CEA-Institut National des Sciences et Techniques Nucleaires (INSTN), Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). UECCC

    2004-07-01

    Room-temperature ionic liquids (RTILs) are promising solvent alternatives in organic synthesis, catalysis, electrochemistry and separation processes. They appear as interesting media for the elaboration of separation processes in the nuclear fuel cycle. However, the partitioning of metallic species in liquid-liquid extraction is largely limited by the low complexation properties of the hydrophobia ionic liquids: in general, hydrophobic RTILs are non-coordinating, and the highly hydrated metal ions remain in the aqueous phase. (orig.)

  19. Density, viscosity and phase equilibria study of {ethylsulfate-based ionic liquid + water} binary systems as a function of temperature and composition

    Energy Technology Data Exchange (ETDEWEB)

    Królikowska, Marta, E-mail: mlaskowska@ch.pw.edu.pl; Lipiński, Paweł; Maik, Daria

    2014-04-01

    Highlights: • The [EMPIP][EtSO{sub 4}], [EMMOR][EtSO{sub 4}], [EMPYR][EtSO{sub 4}] and its aqueous mixtures have been studied. • The density, dynamic viscosity and SLE have been determined. • The excess molar volumes and viscosity deviations have been calculated. • The NRTL, Wilson, UNIQUAC, Redlich–Kister and VFT equations have been used to correlate the experimental data. - Abstract: This paper is a continuation of our investigation on physicochemical and thermodynamic properties of ionic liquids and its aqueous solutions. In this work the density, ρ and dynamic viscosity, η have been determined for binary mixtures of the ionic liquids: 1-ethyl-1-methyl-piperidinium ethylsulfate, [EMPIP][EtSO{sub 4}], 1-ethyl-1-methylmorpholinium ethylsulfate, [EMMOR][EtSO{sub 4}] and 1-ethyl-1-methylpyrrolidinium ethylsulfate, [EMPYR][EtSO{sub 4}] with water at wide temperature and composition range at atmospheric pressure. From experimental values of the density, ρ and dynamic viscosity, η the excess molar volumes, V{sup E} and viscosity deviations, Δη were calculated and correlated using Redlich–Kister polynomial equation. The (solid + liquid) phase equilibria, SLE for the tested binary mixtures have been determined by well-known dynamic method at a wide range of composition and temperature at atmospheric pressure. For comparison, the SLE data for {[EMPYR][EtSO_4] + water} binary mixtures have been determined using DSC technique. The experimental SLE data have been correlated by means of NRTL, UNIQUAC and Wilson equations. Additionally, the basic thermal properties of the pure ILs, that is, the glass-transition temperature, T{sub g,1} as well as the heat capacity at the glass-transition temperature, ΔC{sub p(g),1}, melting temperature, T{sub m} and enthalpy of melting, Δ{sub m}H have been measured using a differential scanning microcalorimetry technique (DSC). Decomposition of the ILs was detected by the simultaneous TG/DTA experiments. The choice of the

  20. Density, viscosity and phase equilibria study of {ethylsulfate-based ionic liquid + water} binary systems as a function of temperature and composition

    International Nuclear Information System (INIS)

    Highlights: • The [EMPIP][EtSO4], [EMMOR][EtSO4], [EMPYR][EtSO4] and its aqueous mixtures have been studied. • The density, dynamic viscosity and SLE have been determined. • The excess molar volumes and viscosity deviations have been calculated. • The NRTL, Wilson, UNIQUAC, Redlich–Kister and VFT equations have been used to correlate the experimental data. - Abstract: This paper is a continuation of our investigation on physicochemical and thermodynamic properties of ionic liquids and its aqueous solutions. In this work the density, ρ and dynamic viscosity, η have been determined for binary mixtures of the ionic liquids: 1-ethyl-1-methyl-piperidinium ethylsulfate, [EMPIP][EtSO4], 1-ethyl-1-methylmorpholinium ethylsulfate, [EMMOR][EtSO4] and 1-ethyl-1-methylpyrrolidinium ethylsulfate, [EMPYR][EtSO4] with water at wide temperature and composition range at atmospheric pressure. From experimental values of the density, ρ and dynamic viscosity, η the excess molar volumes, VE and viscosity deviations, Δη were calculated and correlated using Redlich–Kister polynomial equation. The (solid + liquid) phase equilibria, SLE for the tested binary mixtures have been determined by well-known dynamic method at a wide range of composition and temperature at atmospheric pressure. For comparison, the SLE data for {[EMPYR][EtSO4] + water} binary mixtures have been determined using DSC technique. The experimental SLE data have been correlated by means of NRTL, UNIQUAC and Wilson equations. Additionally, the basic thermal properties of the pure ILs, that is, the glass-transition temperature, Tg,1 as well as the heat capacity at the glass-transition temperature, ΔCp(g),1, melting temperature, Tm and enthalpy of melting, ΔmH have been measured using a differential scanning microcalorimetry technique (DSC). Decomposition of the ILs was detected by the simultaneous TG/DTA experiments. The choice of the ionic liquids allowed to determine the effect of cation structure on

  1. Nanoscale Ionic Materials

    KAUST Repository

    Rodriguez, Robert

    2008-11-18

    Polymer nanocomposites (nanoparticles dispersed in a polymer matrix) have been the subject of intense research for almost two decades in both academic and industrial settings. This interest has been fueled by the ability of nanocomposites to not only improve the performance of polymers, but also by their ability to introduce new properties. Yet, there are still challenges that polymer nanocomposites must overcome to reach their full potential. In this Research News article we discuss a new class of hybrids termed nanoparticle ionic materials (NIMS). NIMS are organic-inorganic hybrid materials comprising a nanoparticle core functionalized with a covalently tethered ionic corona. They are facilely engineered to display flow properties that span the range from glassy solids to free flowing liquids. These new systems have unique properties that can overcome some of the challenges facing nanocomosite materials. © 2008 WILEY-VCH Verlag GmbH & Co. KGaA.

  2. Flow of Aqueous Humor

    Science.gov (United States)

    ... Facebook Twitter Google Plus Email Print this page Flow of Aqueous Humor Most, but not all, forms ... aqueous humor) produced by the eye's ciliary body flows out freely (follow blue arrow). Aqueous humor flows ...

  3. Use of Ionic Liquids in Recycle of Palladium Catalysts for Synthesis of Polyketone

    Institute of Scientific and Technical Information of China (English)

    TIAN Jing; GUO Jintang; ZHANG Xuemei; ZHANG Xin; XU Yongshen

    2008-01-01

    Room temperature ionic liquids as solvents for palladium-catalyzed copolymerization of carbon monoxide and styrene were prepared by reaction of aqueous lead tetrafluoroborate with correspond-ing chloride or bromide salts. The recyclability of palladium composite catalyst in various ionic liquids was investigated.[Pd(bipy)2][BF4]2 showed a lower catalytic activity than [Pd(bipy)2][PF6]2 in similar conditions, although the catalytic activity of each composite catalyst in ionic liquids still existed after 4 successive recycles. It was shown the catalytic activity of palladium composite catalyst was higher than that of the catalyst formed in situ from palladium acetate, 2,2'-bipyridyl, and HA (A=PF6-, BF4-) in ionic liquids. The effects of volume of ionic liquids, reaction time, and the dosage of benzoquinone on the copolymerization were also studied.

  4. Course on Ionic Channels

    CERN Document Server

    1986-01-01

    This book is based on a series of lectures for a course on ionic channels held in Santiago, Chile, on November 17-20, 1984. It is intended as a tutorial guide on the properties, function, modulation, and reconstitution of ionic channels, and it should be accessible to graduate students taking their first steps in this field. In the presentation there has been a deliberate emphasis on the spe­ cific methodologies used toward the understanding of the workings and function of channels. Thus, in the first section, we learn to "read" single­ channel records: how to interpret them in the theoretical frame of kinetic models, which information can be extracted from gating currents in re­ lation to the closing and opening processes, and how ion transport through an open channel can be explained in terms of fluctuating energy barriers. The importance of assessing unequivocally the origin and purity of mem­ brane preparations and the use of membrane vesicles and optical tech­ niques in the stUGY of ionic channels a...

  5. Chemical reactions at aqueous interfaces

    Science.gov (United States)

    Vecitis, Chad David

    2009-12-01

    Interfaces or phase boundaries are a unique chemical environment relative to individual gas, liquid, or solid phases. Interfacial reaction mechanisms and kinetics are often at variance with homogeneous chemistry due to mass transfer, molecular orientation, and catalytic effects. Aqueous interfaces are a common subject of environmental science and engineering research, and three environmentally relevant aqueous interfaces are investigated in this thesis: 1) fluorochemical sonochemistry (bubble-water), 2) aqueous aerosol ozonation (gas-water droplet), and 3) electrolytic hydrogen production and simultaneous organic oxidation (water-metal/semiconductor). Direct interfacial analysis under environmentally relevant conditions is difficult, since most surface-specific techniques require relatively `extreme' conditions. Thus, the experimental investigations here focus on the development of chemical reactors and analytical techniques for the completion of time/concentration-dependent measurements of reactants and their products. Kinetic modeling, estimations, and/or correlations were used to extract information on interfacially relevant processes. We found that interfacial chemistry was determined to be the rate-limiting step to a subsequent series of relatively fast homogeneous reactions, for example: 1) Pyrolytic cleavage of the ionic headgroup of perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) adsorbed to cavitating bubble-water interfaces during sonolysis was the rate-determining step in transformation to their inorganic constituents carbon monoxide, carbon dioxide, and fluoride; 2) ozone oxidation of aqueous iodide to hypoiodous acid at the aerosol-gas interface is the rate-determining step in the oxidation of bromide and chloride to dihalogens; 3) Electrolytic oxidation of anodic titanol surface groups is rate-limiting for the overall oxidation of organics by the dichloride radical. We also found chemistry unique to the interface, for example: 1

  6. Direct Capture of Organic Acids From Fermentation Media Using Ionic Liquids

    Energy Technology Data Exchange (ETDEWEB)

    Klasson, K.T.

    2004-11-03

    Several ionic liquids have been investigated for the extraction of organic acids from fermentation broth. Partitioning of representative organic acids (lactic, acetic, and succinic) between aqueous solution and nine hydrophobic ionic liquids was measured. The extraction efficiencies were strongly dependent on pH of the aqueous phase. Distribution coefficient was very good (approximately 60) at low succinic acid concentrations for one of the ionic liquids (trihexyltetradecylphosphonium methanesulfonate) at neutral pH. However, this ionic liquid had to be diluted with nonanol due to its high viscosity in order to be useful. A diluent (trioctylamine) was also added to this mixture. The results suggest that an extraction system based on ionic liquids may be feasible for succinic acid recovery from fermentation broth and that two ideal extraction stages are needed to reduce the concentration from 33 g/L to 1 g/L of succinic acid. Further studies are needed to evaluate other issues related to practical applications, including ionic liquid loss in the process, toxicity effects of ionic liquids during simultaneous fermentation and extractions.

  7. Slab melting and magma generation beneath the southern Cascade Arc

    Science.gov (United States)

    Walowski, K. J.; Wallace, P. J.; Clynne, M. A.

    2014-12-01

    Magma formation in subduction zones is interpreted to be caused by flux melting of the mantle wedge by fluids derived from dehydration of the downgoing oceanic lithosphere. In the Cascade Arc and other hot-slab subduction zones, however, most dehydration reactions occur beneath the forearc, necessitating a closer investigation of magma generation processes in this setting. Recent work combining 2-D steady state thermal models and the hydrogen isotope composition of olivine-hosted melt inclusions from the Lassen segment of the Cascades (Walowski et al., 2014; in review) has shown that partial melting of the subducted basaltic crust may be a key part of the subduction component in hot arcs. In this model, fluids from the slab interior (hydrated upper mantle) rise through the slab and cause flux-melting of the already dehydrated MORB volcanics in the upper oceanic crust. In the Shasta and Lassen segments of the southern Cascades, support for this interpretation comes from primitive magmas that have MORB-like Sr isotope compositions that correlate with subduction component tracers (H2O/Ce, Sr/P) (Grove et al. 2002, Borg et al. 2002). In addition, mass balance calculations of the composition of subduction components show ratios of trace elements to H2O that are at the high end of the global arc array (Ruscitto et al. 2012), consistent with the role of a slab-derived melt. Melting of the subducted basaltic crust should contribute a hydrous dacitic or rhyolitic melt (e.g. Jego and Dasgupta, 2013) to the mantle wedge rather than an H2O-rich aqueous fluid. We are using pHMELTS and pMELTS to model the reaction of hydrous slab melts with mantle peridotite as the melts rise through the inverted thermal gradient in the mantle wedge. The results of the modeling will be useful for understanding magma generation processes in arcs that are associated with subduction of relatively young oceanic lithosphere.

  8. Emerging melt quality control solution technologies for aluminium melt

    Institute of Scientific and Technical Information of China (English)

    Arturo Pascual, Jr

    2009-01-01

    The newly developed "MTS 1500" Melt Treatment System is performing the specifically required melt treatment operations like degassing, cleaning, modification and/or grain refinement by an automated process in one step and at the same location. This linked process is saving time, energy and metal losses allowing-by automated dosage of the melt treatment agents-the production of a consistent melt quality batch after batch. By linking the MTS Metal Treatment System with sensors operating on-line in the melt, i.e., with a hydrogen sensor "Alspek H", a fully automated control of parts of the process chain like degassing is possible. This technology does guarantee a pre-specified and documented melt quality in each melt treatment batch. Furthermore, to ensure that castings are consistent and predictable there is a growing realization that critical measuring the cleanliness of an aluminum melt but these can be both slow and costly. A simple, rapid and meaningful method of measuring and bench marking the cleanliness of an aluminum melt has been developed to offer the foundry a practical method of measuring melt cleanliness.This paper shows the structure and performance of the integrated MTS melt treatment process and documents achieved melt quality standards after degassing, cleaning, modification and grain refinement operations under real foundry conditions. It also provides an insight on a melt cleanliness measuring device "Alspek MQ" to provide foundry men better tools in meeting the increasing quality and tighter specification demand from the industry.

  9. GLASS MELTING PHENOMENA, THEIR ORDERING AND MELTING SPACE UTILISATION

    Directory of Open Access Journals (Sweden)

    Němec L.

    2013-12-01

    Full Text Available Four aspects of effective glass melting have been defined – namely the fast kinetics of partial melting phenomena, a consideration of the melting phenomena ordering, high utilisation of the melting space, and effective utilisation of the supplied energy. The relations were defined for the specific melting performance and specific energy consumption of the glass melting process which involve the four mentioned aspects of the process and indicate the potentials of effective melting. The quantity “space utilisation” has been treated in more detail as an aspect not considered in practice till this time. The space utilisation was quantitatively defined and its values have been determined for the industrial melting facility by mathematical modelling. The definitions of the specific melting performance and specific energy consumption have been used for assessment of the potential impact of a controlled melt flow and high space utilisation on the melting process efficiency on the industrial scale. The results have shown that even the partial control of the melt flow, leading to the partial increase of the space utilisation, may considerably increase the melting performance, whereas a decrease of the specific energy consumption was determined to be between 10 - 15 %.

  10. Viscosity Measurement for Tellurium Melt

    Science.gov (United States)

    Lin, Bochuan; Li, Chao; Ban, Heng; Scripa, Rosalia N.; Su, Ching-Hua; Lehoczky, Sandor L.

    2006-01-01

    The viscosity of high temperature Te melt was measured using a new technique in which a rotating magnetic field was applied to the melt sealed in a suspended ampoule, and the torque exerted by rotating melt flow on the ampoule wall was measured. Governing equations for the coupled melt flow and ampoule torsional oscillation were solved, and the viscosity was extracted from the experimental data by numerical fitting. The computational result showed good agreement with experimental data. The melt velocity transient initiated by the rotating magnetic field reached a stable condition quickly, allowing the viscosity and electrical conductivity of the melt to be determined in a short period.

  11. Inorganic materials synthesis in ionic liquids

    Directory of Open Access Journals (Sweden)

    Christoph Janiak

    2014-01-01

    Full Text Available The field of "inorganic materials from ionic liquids" (ILs is a young and dynamically growing research area for less than 10 years. The ionothermal synthesis in ILs is often connected with the preparation of nanomaterials, the use of microwave heating and in part also ultrasound. Inorganic material synthesis in ILs allows obtaining phases which are not accessible in conventional organic or aqueous solvents or with standard methods of solid-state chemistry or under such mild conditions. Cases at hand include "ligand-free" metal nanoparticles without added stabilizing capping ligands, inorganic or inorganic-organic hybrid solid-state compounds, large polyhedral clusters and exfoliated graphene from low-temperature synthesis. There are great expectations that ILs open routes towards new, possibly unknown, inorganic materials with advantageous properties that cannot (or only with great difficulty be made via conventional processes.

  12. Neptunium (V) Adsorption to a Halophilic Bacterium Under High Ionic Strength Conditions: A Surface Complexation Modeling Approach

    Energy Technology Data Exchange (ETDEWEB)

    Ams, David A [Los Alamos National Laboratory

    2012-06-11

    Rationale for experimental design: Np(V) -- important as analog for Pu(V) and for HLW scenarios; High ionic strength -- relevant to salt-based repositories such as the WIPP; Halophilic microorganisms -- representative of high ionic strength environments. For the first time showed: Significant adsorbant to halophilic microorganisms over entire pH range under high ionic strength conditions; Strong influence of ionic strength with increasing adsorption with increasing ionic strength (in contrast to trends of previous low ionic strength studies); Effect of aqueous Np(V) and bacterial surface site speciation on adsorption; and Developed thermodynamic models that can be incorporated into geochemical speciation models to aid in the prediction of the fate and transport of Np(V) in more complex systems.

  13. Investigating Ionic Effects Applied to Water Based Organocatalysed Aldol Reactions

    Directory of Open Access Journals (Sweden)

    Joshua P. Delaney

    2011-12-01

    Full Text Available Saturated aqueous solutions of various common salts were examined for their effect on aqueous aldol reactions catalysted by a highly active C2-symmetric diprolinamide organocatalyst developed in our laboratory. With respect to the aldol reaction between cyclohexanone and 4-nitrobenzaldehyde, deionised water was always a superior medium to salt solutions though some correlation to increasing anion size and depression in enantiomeric excess could be observed. Additionally, the complete inhibition of catalyst activity observed when employing tap water could be alleviated by the inclusion of ethylenediaminetetraacetate (EDTA into the aqueous media prior to reaction initiation. Extension of these reaction conditions demonstrated that these ionic effects vary on a case-to-case basis depending on the ketone/aldehyde combination.

  14. Understanding the impact of the central atom on the ionic liquid behavior: phosphonium vs ammonium cations.

    Science.gov (United States)

    Carvalho, Pedro J; Ventura, Sónia P M; Batista, Marta L S; Schröder, Bernd; Gonçalves, Fernando; Esperança, José; Mutelet, Fabrice; Coutinho, João A P

    2014-02-14

    The influence of the cation's central atom in the behavior of pairs of ammonium- and phosphonium-based ionic liquids was investigated through the measurement of densities, viscosities, melting temperatures, activity coefficients at infinite dilution, refractive indices, and toxicity against Vibrio fischeri. All the properties investigated are affected by the cation's central atom nature, with ammonium-based ionic liquids presenting higher densities, viscosities, melting temperatures, and enthalpies. Activity coefficients at infinite dilution show the ammonium-based ionic liquids to present slightly higher infinite dilution activity coefficients for non-polar solvents, becoming slightly lower for polar solvents, suggesting that the ammonium-based ionic liquids present somewhat higher polarities. In good agreement these compounds present lower toxicities than the phosphonium congeners. To explain this behavior quantum chemical gas phase DFT calculations were performed on isolated ion pairs at the BP-TZVP level of theory. Electronic density results were used to derive electrostatic potentials of the identified minimum conformers. Electrostatic potential-derived CHelpG and Natural Population Analysis charges show the P atom of the tetraalkylphosphonium-based ionic liquids cation to be more positively charged than the N atom in the tetraalkylammonium-based analogous IL cation, and a noticeable charge delocalization occurring in the tetraalkylammonium cation, when compared with the respective phosphonium congener. It is argued that this charge delocalization is responsible for the enhanced polarity observed on the ammonium based ionic liquids explaining the changes in the thermophysical properties observed. PMID:24527930

  15. Understanding the impact of the central atom on the ionic liquid behavior: Phosphonium vs ammonium cations

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, Pedro J.; Ventura, Sónia P. M.; Batista, Marta L. S.; Schröder, Bernd; Coutinho, João A. P., E-mail: jcoutinho@ua.pt [CICECO, Departamento de Química, Universidade de Aveiro, 3810-193 Aveiro (Portugal); Gonçalves, Fernando [Departamento de Biologia e CESAM (Centro de Estudos do Ambiente e do Mar), Universidade de Aveiro, 3810-193 Aveiro (Portugal); Esperança, José [Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, 2780-901 Oeiras (Portugal); Mutelet, Fabrice [Laboratoire Réactions et Génie des Procédés, CNRS (UPR3349), Nancy-Université, 1 rue Grandville, BP 20451 54001 Nancy (France)

    2014-02-14

    The influence of the cation's central atom in the behavior of pairs of ammonium- and phosphonium-based ionic liquids was investigated through the measurement of densities, viscosities, melting temperatures, activity coefficients at infinite dilution, refractive indices, and toxicity against Vibrio fischeri. All the properties investigated are affected by the cation's central atom nature, with ammonium-based ionic liquids presenting higher densities, viscosities, melting temperatures, and enthalpies. Activity coefficients at infinite dilution show the ammonium-based ionic liquids to present slightly higher infinite dilution activity coefficients for non-polar solvents, becoming slightly lower for polar solvents, suggesting that the ammonium-based ionic liquids present somewhat higher polarities. In good agreement these compounds present lower toxicities than the phosphonium congeners. To explain this behavior quantum chemical gas phase DFT calculations were performed on isolated ion pairs at the BP-TZVP level of theory. Electronic density results were used to derive electrostatic potentials of the identified minimum conformers. Electrostatic potential-derived CHelpG and Natural Population Analysis charges show the P atom of the tetraalkylphosphonium-based ionic liquids cation to be more positively charged than the N atom in the tetraalkylammonium-based analogous IL cation, and a noticeable charge delocalization occurring in the tetraalkylammonium cation, when compared with the respective phosphonium congener. It is argued that this charge delocalization is responsible for the enhanced polarity observed on the ammonium based ionic liquids explaining the changes in the thermophysical properties observed.

  16. Ionic liquids, electrolyte solutions including the ionic liquids, and energy storage devices including the ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Gering, Kevin L.; Harrup, Mason K.; Rollins, Harry W.

    2015-12-08

    An ionic liquid including a phosphazene compound that has a plurality of phosphorus-nitrogen units and at least one pendant group bonded to each phosphorus atom of the plurality of phosphorus-nitrogen units. One pendant group of the at least one pendant group comprises a positively charged pendant group. Additional embodiments of ionic liquids are disclosed, as are electrolyte solutions and energy storage devices including the embodiments of the ionic liquid.

  17. Mechanisms and rules of anion partition into ionic liquids: phenolate ions in ionic liquid/water biphasic systems.

    Science.gov (United States)

    Katsuta, Shoichi; Nakamura, Ko-ichi; Kudo, Yoshihiro; Takeda, Yasuyuki

    2012-01-19

    It is important to understand the mechanisms and general rules of ion partitioning in hydrophobic ionic liquid (IL)/water biphasic systems in order to predict the extractability of an ionic species with various ILs. In this study, we have investigated the partition of picrate ion (target anion, T(-)) from aqueous sodium picrate solutions into several ILs and the accompanying changes in aqueous concentrations of the IL component cation (C(+)) and anion (A(-)) at 298.2 K. The main ILs examined are 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide, 1-butyl-3-methylimidazolium hexafluorophosphate, and 1-methyl-3-octylimidazolium bis(trifluoromethanesulfonyl)amide. The aqueous concentrations of C(+) and A(-) decreased and increased, respectively, with the extraction of T(-) into the IL phase. From the standpoint of equilibrium, the partition behavior of T(-) can be explained both by the anion exchange with A(-) in the IL phase and by the ion pair extraction with C(+) in the aqueous phase. The aqueous concentrations of C(+) and A(-) are governed by the solubility product of the IL (K(sp)). The distribution ratio of T(-) is expressed as a function of Δ[T(-)](W), namely, the difference between the initial and equilibrium concentrations of T(-) in the aqueous phase; the distribution ratio of T(-) is nearly constant when Δ[T(-)](W) < K(sp)(1/2), but decreases with increasing Δ[T(-)](W) in the larger Δ[T(-)](W) region. The equilibrium constants of the ion pair extraction and the ion exchange extraction have been determined for picrate and other phenolate ions whose partition data were previously reported. The dependences of the extraction constants and extractability on the kinds of IL component ions can be quantitatively explained on the basis of the variations of K(sp).

  18. Thermodynamics of Oligonucleotide Duplex Melting

    Science.gov (United States)

    Schreiber-Gosche, Sherrie; Edwards, Robert A.

    2009-01-01

    Melting temperatures of oligonucleotides are useful for a number of molecular biology applications, such as the polymerase chain reaction (PCR). Although melting temperatures are often calculated with simplistic empirical equations, application of thermodynamics provides more accurate melting temperatures and an opportunity for students to apply…

  19. Melting of polydisperse hard disks

    NARCIS (Netherlands)

    Pronk, S.; Frenkel, D.

    2004-01-01

    The melting of a polydisperse hard-disk system is investigated by Monte Carlo simulations in the semigrand canonical ensemble. This is done in the context of possible continuous melting by a dislocation-unbinding mechanism, as an extension of the two-dimensional hard-disk melting problem. We find th

  20. Nanoporous membranes with electrochemically switchable, chemically stabilized ionic selectivity

    Science.gov (United States)

    Small, Leo J.; Wheeler, David R.; Spoerke, Erik D.

    2015-10-01

    Nanopore size, shape, and surface charge all play important roles in regulating ionic transport through nanoporous membranes. The ability to control these parameters in situ provides a means to create ion transport systems tunable in real time. Here, we present a new strategy to address this challenge, utilizing three unique electrochemically switchable chemistries to manipulate the terminal functional group and control the resulting surface charge throughout ensembles of gold plated nanopores in ion-tracked polycarbonate membranes 3 cm2 in area. We demonstrate the diazonium mediated surface functionalization with (1) nitrophenyl chemistry, (2) quinone chemistry, and (3) previously unreported trimethyl lock chemistry. Unlike other works, these chemistries are chemically stabilized, eliminating the need for a continuously applied gate voltage to maintain a given state and retain ionic selectivity. The effect of surface functionalization and nanopore geometry on selective ion transport through these functionalized membranes is characterized in aqueous solutions of sodium chloride at pH = 5.7. The nitrophenyl surface allows for ionic selectivity to be irreversibly switched in situ from cation-selective to anion-selective upon reduction to an aminophenyl surface. The quinone-terminated surface enables reversible changes between no ionic selectivity and a slight cationic selectivity. Alternatively, the trimethyl lock allows ionic selectivity to be reversibly switched by up to a factor of 8, approaching ideal selectivity, as a carboxylic acid group is electrochemically revealed or hidden. By varying the pore shape from cylindrical to conical, it is demonstrated that a controllable directionality can be imparted to the ionic selectivity. Combining control of nanopore geometry with stable, switchable chemistries facilitates superior control of molecular transport across the membrane, enabling tunable ion transport systems.Nanopore size, shape, and surface charge all play

  1. Nanoporous membranes with electrochemically switchable, chemically stabilized ionic selectivity

    Science.gov (United States)

    Small, Leo J.; Wheeler, David R.; Spoerke, Erik D.

    2015-10-01

    Nanopore size, shape, and surface charge all play important roles in regulating ionic transport through nanoporous membranes. The ability to control these parameters in situ provides a means to create ion transport systems tunable in real time. Here, we present a new strategy to address this challenge, utilizing three unique electrochemically switchable chemistries to manipulate the terminal functional group and control the resulting surface charge throughout ensembles of gold plated nanopores in ion-tracked polycarbonate membranes 3 cm2 in area. We demonstrate the diazonium mediated surface functionalization with (1) nitrophenyl chemistry, (2) quinone chemistry, and (3) previously unreported trimethyl lock chemistry. Unlike other works, these chemistries are chemically stabilized, eliminating the need for a continuously applied gate voltage to maintain a given state and retain ionic selectivity. The effect of surface functionalization and nanopore geometry on selective ion transport through these functionalized membranes is characterized in aqueous solutions of sodium chloride at pH = 5.7. The nitrophenyl surface allows for ionic selectivity to be irreversibly switched in situ from cation-selective to anion-selective upon reduction to an aminophenyl surface. The quinone-terminated surface enables reversible changes between no ionic selectivity and a slight cationic selectivity. Alternatively, the trimethyl lock allows ionic selectivity to be reversibly switched by up to a factor of 8, approaching ideal selectivity, as a carboxylic acid group is electrochemically revealed or hidden. By varying the pore shape from cylindrical to conical, it is demonstrated that a controllable directionality can be imparted to the ionic selectivity. Combining control of nanopore geometry with stable, switchable chemistries facilitates superior control of molecular transport across the membrane, enabling tunable ion transport systems.Nanopore size, shape, and surface charge all play

  2. Surface modification of nanodiamond in aqueous medium

    Institute of Scientific and Technical Information of China (English)

    许向阳; 朱永伟; 王柏春; 沈湘黔

    2003-01-01

    The methods of chemical-mechanical treatments(CMT)were utilized for surface modification of nanodiamond in aqueous medium,and a considerably stable suspension system was thus obtained.The size of all the particles in the provided system was less than 100 nm with a narrow distribution and excellent stability,and no obvious change of particle crystal structure after the treatments was observed.The mechanism of the treatments was also discussed.The results show that,because of mechanical treatment effect,addition of ionic surfactants and inorganic regulators,the ζ-potential of nanodiamond shifts upwards during the treatments,and the composition of surface functional groups changes.Carboxyl and hydroxyl groups are intensified after the surface modification,which may contribute to the improvement of dispersion and stability.Meanwhile,the addition of non-ionic polymer can also benefit the suspension stability.

  3. Improving the Enzyme Catalytic Efficiency Using Ionic Liquids with Kosmotropic Anions

    Institute of Scientific and Technical Information of China (English)

    ZHAO, Hua; CAMPBELL, Sophia; SOLOMON, Jonathan; SONG, Zhi-Yan; OLUBAJO, Olarongbe

    2006-01-01

    The kosmotropicity of cations and anions in ionic liquids has a strong influence on the enzyme catalytic efficiency in aqueous environments. The kosmotropic anion CF3COO- seemed to activate the protease, and the chaotropic anions tended to destabilize the enzyme.

  4. Ionic Liquids Derived from the Chiral Pool: New Media for Fine Chemistry

    Institute of Scientific and Technical Information of China (English)

    A.C. Gaumont; D. Bregeon; J. Levillain; C. Baudequin; F. Guillen; J.C. Plaquevent

    2005-01-01

    @@ 1Introduction Ionic liquids (Ils) are low melting point salts, which are characterized by properties such as high ability to dissolve organic, organometallic and even inorganic compounds, absence of flammability, lack of measurable vapour pressure and high thermal stability. Due to these peculiar properties, they have recently attracted considerable attention as greener alternatives to volatile organic solvents[1]. A few chiral ionic liquids, which could provide a renewal in the field of chiral solvents, have also been reported recently[2]. Herein, we will present the synthesis of a new family of ionic liquids based on a thiazolinium skeleton. Preliminary results on the use of these chiral ionic liquids in the field of chiral recognition and organic synthesis will also be reported.

  5. Synthesis and Characterization of Tetramethylethylenediamine-Based Hypergolic Ionic Liquids

    Science.gov (United States)

    Fei, Teng; Cai, Huiwu; Zhang, Yanqiang; Liu, Long; Zhang, Suojiang

    2016-04-01

    Four energetic salts (including two ionic liquids) based on 2-(dimethylamino)-N,N,N-trimethylethanaminium and N,N‧-dialkyl-N,N,N‧,N‧-tetramethylethane-1,2-diaminium was prepared and characterized by 1H- and 13C-NMR, infrared and Raman spectroscopies, and elemental analysis. Their physicochemical properties such as melting and decomposition temperatures, density, viscosity, heat of formation, detonation performance, and specific impulse were measured or calculated. With thermal stability up to 200°C, the resulting ionic liquids show densities from 1.02 to 1.19 g cm-3 and heats of formation from 85.1 to 154.4 kJ mol-1. Moreover, 2-(dimethylamino)-N,N,N-trimethylethanaminium dicyanamide is hypergolic with the oxidizer (100% HNO3) and exhibits potential as a green fuel for bipropellants.

  6. Pysico-chemical properties of hydrophobic ionic liquids containing1-octylpyridinium, 1-octyl-2-methylpyridinium or1-octyl-4-methylpyridinium cations

    Energy Technology Data Exchange (ETDEWEB)

    Papaiconomou, Nicolas; Salminen, Justin; Lee, Jong-Min; Prausnitz, John M.

    2006-09-15

    This paper reports synthesis of some ionic liquids based on cations 1-octylpyridinium, 1-octyl-2-methylpyridinium or 1-octyl-4-methylpyridinium and anions dicyanamide [N(CN)2]-, bis(trifluoromethylsulfonyl)imide [Tf2N]-, bis(pentafluoroethylsulfonyl)imide [BETI]-, trifluoromethyl sulfonate [TfO]-, nonafluorobutyl sulfonate [NfO]-, tetrafluoroborate [BF4]-, trifluorophenylborate [BF3Ph]- or hexafluoroarsenate [AsF6]-. Melting points, decomposition temperatures, densities, mutual solubilities with water, and viscosities have been measured. Unlike similar ionic liquids containing imidazolium cations, pyridinium ionic liquids studied here are nearly immiscible in water. Viscosities are similar and water content is slightly lower than those for ionic liquids containing imidazolium cations.

  7. Supercooling of aqueous NaCl and KCl solutions under acoustic levitation.

    Science.gov (United States)

    Lü, Y J; Wei, B

    2006-10-14

    The supercooling capability of aqueous NaCl and KCl solutions is investigated at containerless state by using acoustic levitation method. The supercooling of water is obviously enhanced by the alkali metal ions and increases linearly with the augmentation of concentrations. Furthermore, the supercooling depends on the nature of ions and is 2-3 K larger for NaCl solution than that for KCl solution in the present concentration range: Molecular dynamics simulations are performed to reveal the intrinsic correlation between supercoolability and microstructure. The translational and orientational order parameters are applied to quantitatively demonstrate the effect of ionic concentration on the hydrogen-bond network and ice melting point. The disrupted hydrogen-bond structure determines essentially the concentration dependence of supercooling. On the other hand, the introduced acoustic pressure suppresses the increase of supercooling by promoting the growth and coalescence of microbubbles, the effective nucleation catalysts, in water. However, the dissolved ions can weaken this effect, and moreover the degree varies with the ion type. This results in the different supercoolability for NaCl and KCl solutions under the acoustic levitation conditions. PMID:17042605

  8. Precipitation of neptunium dioxide from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, K E

    1999-12-01

    Tens of thousands of metric tons of highly radioactive, nuclear waste have been generated in the US. Currently, there is no treatment or disposal facility for these wastes. Of the radioactive elements in high-level nuclear waste, neptunium (Np) is of particular concern because it has a long half-life and may potentially be very mobile in groundwaters associated with a proposed underground disposal site at Yucca Mountain, Nevada. Aqueous Np concentrations observed in previous, short-term solubility experiments led to calculated potential doses exceeding proposed long-term regulatory limits. However, thermodynamic data for Np at 25 C showed that these observed aqueous Np concentrations were supersaturated with respect to crystalline NpO{sub 2}. It was hypothesized that NpO{sub 2} is the thermodynamically stable solid phase in aqueous solution, but it is slow to form in an aqueous solution of NpO{sub 2}{sup +} on the time scale of previous experiments. The precipitation of NpO{sub 2} would provide significantly lower aqueous Np concentrations leading to calculated doses below proposed regulatory limits. To test this hypothesis, solubility experiments were performed at elevated temperature to accelerate any slow precipitation kinetics. Ionic NpO{sub 2}{sup +} (aq) was introduced into very dilute aqueous solutions of NaCl with initial pH values ranging from 6 to 10. The reaction vessels were placed in an oven and allowed to react at 200 C until steady-state aqueous Np concentrations were observed. In all cases, aqueous Np concentrations decreased significantly from the initial value of 10{sup {minus}4} M. The solids that formed were analyzed by x-ray powder diffraction, x-ray absorption spectroscopy, and scanning electron microscopy. The solids were determined to be high-purity crystals of NpO{sub 2}. This is the first time that crystalline NpO{sub 2} has been observed to precipitate from NpO{sub 2}{sup +}(aq) in near-neutral aqueous solutions. The results obtained

  9. Wettability by Ionic Liquids.

    Science.gov (United States)

    Liu, Hongliang; Jiang, Lei

    2016-01-01

    Ionic liquids (ILs) have become particularly attractive recently because they have demonstrated themselves to be important construction units in the broad fields of chemistry and materials science, from catalysis and synthesis to analysis and electrochemistry, from functional fluids to clean energy, from nanotechnology to functional materials. One of the greatest issues that determines the performance of ILs is the wettability of correlated surfaces. In this concept article, the key developments and issues in IL wettability are surveyed, including the electrowetting of ILs in gas-liquid-solid systems and liquid-liquid-solid systems, ILs as useful probe fluids, the superwettability of Ils, and future directions in IL wettability. This should generate extensive interest in the field and encourage more scientists to engage in this area to tackle its scientific challenges. PMID:26619157

  10. Hydrogen bonding in ionic liquids.

    Science.gov (United States)

    Hunt, Patricia A; Ashworth, Claire R; Matthews, Richard P

    2015-03-01

    Ionic liquids (IL) and hydrogen bonding (H-bonding) are two diverse fields for which there is a developing recognition of significant overlap. Doubly ionic H-bonds occur when a H-bond forms between a cation and anion, and are a key feature of ILs. Doubly ionic H-bonds represent a wide area of H-bonding which has yet to be fully recognised, characterised or explored. H-bonds in ILs (both protic and aprotic) are bifurcated and chelating, and unlike many molecular liquids a significant variety of distinct H-bonds are formed between different types and numbers of donor and acceptor sites within a given IL. Traditional more neutral H-bonds can also be formed in functionalised ILs, adding a further level of complexity. Ab initio computed parameters; association energies, partial charges, density descriptors as encompassed by the QTAIM methodology (ρBCP), qualitative molecular orbital theory and NBO analysis provide established and robust mechanisms for understanding and interpreting traditional neutral and ionic H-bonds. In this review the applicability and extension of these parameters to describe and quantify the doubly ionic H-bond has been explored. Estimating the H-bonding energy is difficult because at a fundamental level the H-bond and ionic interaction are coupled. The NBO and QTAIM methodologies, unlike the total energy, are local descriptors and therefore can be used to directly compare neutral, ionic and doubly ionic H-bonds. The charged nature of the ions influences the ionic characteristics of the H-bond and vice versa, in addition the close association of the ions leads to enhanced orbital overlap and covalent contributions. The charge on the ions raises the energy of the Ylp and lowers the energy of the X-H σ* NBOs resulting in greater charge transfer, strengthening the H-bond. Using this range of parameters and comparing doubly ionic H-bonds to more traditional neutral and ionic H-bonds it is clear that doubly ionic H-bonds cover the full range of weak

  11. Stable and water-tolerant ionic liquid ferrofluids.

    Science.gov (United States)

    Jain, Nirmesh; Zhang, Xiaoli; Hawkett, Brian S; Warr, Gregory G

    2011-03-01

    Ionic liquid ferrofluids have been prepared containing both bare and sterically stabilized 8-12 nm diameter superparamagnetic iron oxide nanoparticles, which remain stable for several months in both protic ethylammonium and aprotic imidazolium room-temperature ionic liquids. These ferrofluids exhibit spiking in static magnetic fields similar to conventional aqueous and nonaqueous ferrofluids. Ferrofluid stability was verified by following the flocculation and settling behavior of dilute nanoparticle dispersions. Although bare nanoparticles showed excellent stability in some ILs, they were unstable in others, and exhibited limited water tolerance. Stability was achieved by incorporating a thin polymeric steric stabilization layer designed to be compatible with the IL. This confers the added benefit of imbuing the ILF with a high tolerance to water. PMID:21338083

  12. Simulation of Ionic Aggregation and Ion Dynamics in Model Ionomers

    Science.gov (United States)

    Frischknecht, Amalie L.

    2012-02-01

    Ionomers, polymers containing a small fraction of covalently bound ionic groups, are of interest as possible electrolytes in batteries. A single-ion conducting polymer electrolyte would be safer and have higher efficiency than the currently-used liquid electrolytes. However, to date ionomeric materials do not have sufficiently high conductivities for practical application. This is most likely because the ions tend to form aggregates, leading to slow ion transport. A key question is therefore how molecular structure affects the ionic aggregation and ion dynamics. To probe these structure-property relationships, we have performed molecular simulations of a set of recently synthesized poly(ethylene-co-acrylic acid) copolymers and ionomers, with a focus on the morphology of the ionic aggregates. The ionomers have a precise, constant spacing of charged groups, making them ideal for direct comparisons with simulations. Ab initio calculations give insight into the expected coordination of cations with fragments of the ionomers. All-atom molecular dynamics (MD) simulations of the ionomer melt show aggregation of the ionic groups into extended string-like clusters. An extensive set of coarse-grained molecular dynamics simulations extend the results to longer times and larger length scales. The structure factors calculated from the MD simulations compare favorably with x-ray scattering data. Furthermore, the simulations give a detailed picture of the sizes, shapes, and composition of the ionic aggregates, and how they depend on polymer architecture. Implications for ion transport will be discussed. [Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  13. Melting of Ice under Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Schwegler, E; Sharma, M; Gygi, F; Galli, G

    2008-07-31

    The melting of ice under pressure is investigated with a series of first principles molecular dynamics simulations. In particular, a two-phase approach is used to determine the melting temperature of the ice-VII phase in the range of 10 to 50 GPa. Our computed melting temperatures are consistent with existing diamond anvil cell experiments. We find that for pressures between 10 to 40 GPa, ice melts as a molecular solid. For pressures above {approx}45 GPa there is a sharp increase in the slope of the melting curve due to the presence of molecular dissociation and proton diffusion in the solid, prior to melting. The onset of significant proton diffusion in ice-VII as a function of increasing temperature is found to be gradual and bears many similarities to that of a type-II superionic solid.

  14. Preparing Cu2ZnSnS4 films using the co-electrodeposition method with ionic liquids*

    Institute of Scientific and Technical Information of China (English)

    Chen Yong-Sheng; Wang Ying-Jun; Li Rui; Gu Jin-Hua; Lu Jing-Xiao; Yang Shi-E

    2012-01-01

    Cu2ZnSnS4(CZTS)films are successfully prepared by co-electrodeposition in aqueous ionic solution and sulfurized in elemental sulfur vapor ambient at 400℃ for 30 min using nitrogen as the protective gas.It is found that the CZTS film synthesized at Cu/(Zn+Sn)=0.71 has a kesterite structure,a bandgap of about 1.51 eV,and an absorption coefficient of the order of 104 cm-1.This indicates that the co-electrodeposition method with aqueous ionic solution is a viable process for the growth of CZTS films for application in photovoltaic devices.

  15. Electrochemical Depositions in Ionic Liquids

    OpenAIRE

    De Vreese, Peter

    2013-01-01

    In this PhD thesis, several aspects of the electrodeposition of metals and alloys in ionic liquids were investigated. First, the deposition of brass from choline acetate was studied. Secondly, the electrodeposition of pure molybdenum from ionic liquids based on phosphonium chloride and zinc chloride was treated. In each case, the influence of water, either as a main constituent of the electrolyte or an impurity, was investigated. When comparing electrochemical processes such as electrodeposit...

  16. Ionic Liquid Epoxy Resin Monomers

    Science.gov (United States)

    Paley, Mark S. (Inventor)

    2013-01-01

    Ionic liquid epoxide monomers capable of reacting with cross-linking agents to form polymers with high tensile and adhesive strengths. Ionic liquid epoxide monomers comprising at least one bis(glycidyl) N-substituted nitrogen heterocyclic cation are made from nitrogen heterocycles corresponding to the bis(glycidyl) N-substituted nitrogen heterocyclic cations by a method involving a non-nucleophilic anion, an alkali metal cation, epichlorohydrin, and a strong base.

  17. Modeling the elution of organic chemicals from a melting homogeneous snow pack.

    Science.gov (United States)

    Meyer, Torsten; Wania, Frank

    2011-06-01

    Organic chemicals are often released in peak concentrations from melting snow packs. A simple, mechanistic snowmelt model was developed to simulate and predict the elution of organic substances from melting, homogeneous snow, as influenced by chemical properties and snow pack characteristics. The model calculates stepwise the chemical transport along with the melt water flow in a multi-layered snow pack, based on chemical equilibrium partitioning between the individual bulk snow phases. The model succeeds in reproducing the elution behavior of several organic contaminants observed in previously conducted cold room experiments. The model aided in identifying four different types of enrichment of organic substances during snowmelt. Water soluble substances experience peak releases early during a melt period (type 1), whereas chemicals that strongly sorb to particulate matter (PM) or snow grain surfaces elute at the end of melting (type 2). Substances that are somewhat water soluble and at the same time have a high affinity for snow grain surfaces may exhibit increasing concentrations in the melt water (type 3). Finally, elution sequences involving peak loads both at the beginning and the end of melting are simulated for chemicals that are partially dissolved in the aqueous melt water phase and partially sorbed to PM (type 4). The extent of type 1 enrichment mainly depends on the snow depth, whereby deeper snow generates more pronounced concentration peaks. PM influences the elution behavior of organic chemicals strongly because of the very large natural variability in the type and amount of particles present in snow. Urban and road-side snow rich in PM can generate type 2 concentration peaks at the end of the melt period for even relatively water soluble substances. From a clean, melting snow pack typical for remote regions, even fairly hydrophobic chemicals can be released in type 1 mode while being almost completely dissolved in the aqueous melt water phase. The

  18. Ionic Functionalization of Hydrophobic Colloidal Nanoparticles To Form Ionic Nanoparticles with Enzymelike Properties.

    Science.gov (United States)

    Liu, Yuan; Purich, Daniel L; Wu, Cuichen; Wu, Yuan; Chen, Tao; Cui, Cheng; Zhang, Liqin; Cansiz, Sena; Hou, Weijia; Wang, Yanyue; Yang, Shengyuan; Tan, Weihong

    2015-12-01

    Inorganic colloidal nanoparticles (NPs) stabilized by a layer of hydrophobic surfactant on their surfaces have poor solubility in the aqueous phase, thus limiting their application as biosensors under physiological conditions. Here we report a simple model to ionize various types of hydrophobic colloidal NPs, including FePt, cubic Fe3O4, Pd, CdSe, and NaYF4 (Yb 30%, Er 2%, Nd 1%) NPs, to multicharged (positive and negative) NPs via ligand exchange. Surfaces of neutral hydrophobic NPs were converted to multicharged ions, thus making them soluble in water. Furthermore, peroxidase-like activity was observed for ionic FePt, Fe3O4, Pd, and CdSe NPs, of which FePt and CdSe catalyzed the oxidation of the colorless substrate 3,3',5,5'-tetramethylbenzidine (TMB) to the blue-colored product in the absence of H2O2, while Pd and Fe3O4 catalyzed the oxidization of TMB in the presence of H2O2. With the benefit of the ionic functionalization protocols described herein, colloidal NPs should gain wider use as biomarkers, nanozymes, and biosensors.

  19. MULTIPLE MELTING IN NYLON 1010

    Institute of Scientific and Technical Information of China (English)

    FU Shuren; CHEN Taoyung

    1983-01-01

    Multiple melting behavior of nylon 1010 has been investigated by using DSC instrument. Effects of partial scanning, partial scanning and annealing, heating rate, cooling rate and stepwise annealing on the melting curve were studied. Experimental results indicate that the sample undergoes a process of continuous melting and recrystallization during DSC scanning. Nylon 1010 contains a distribution of crystallites of different degrees of perfection which is strongly dependent on its previous thermal history. From the structural reorganization point of view, the origin of double and multiple peaks of the melting curve is explained.

  20. Synthesis of New Energetic Materials and Ionic Liquids Derived from Metronidazole

    Directory of Open Access Journals (Sweden)

    Miguel A. Romero

    2016-01-01

    Full Text Available Simple and efficient synthetic procedures were established for the preparation of new energetic covalent compounds, salts, and protonated ionic liquids based on the readily available antimicrobial agent metronidazole. Some of these materials exhibit the desirable properties of energetic materials and energetic ionic liquids, such as low vapor pressure, low melting point, good chemical and thermal stability, and high energetic content. For each of the relevant compounds prepared, thermal stability was determined by differential scanning calorimetry. Some of these compounds may be considered promising precursors of pharmaceuticals such as antimicrobial, antiparasitic, antifungal, antineoplastic agents, or enzyme inhibitors.

  1. Physicochemical and thermodynamic characterization of N-alkyl-N-methylpyrrolidinium bromides and its aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Zawadzki, Maciej, E-mail: mzawadzki@ch.pw.edu.pl; Królikowska, Marta; Lipiński, Paweł

    2014-08-10

    Highlights: • The aqueous solutions of bromide-based ionic liquids have been studied. • The synthesis and basic thermal characterization of pure IL have been done. • The density, dynamic viscosity, SLE and VLE have been determined. • The experimental data have been correlated using appropriate equations. - Abstract: This work is a continuation of our research of ionic liquids to investigate the physicochemical and thermodynamic properties of (ionic liquid + water) binary mixtures as a novel alternative working pair for the absorption heat pump cycle. In this work, a series of organic salts: N-propyl-N-methyl-pyrrolidinium bromide, [C{sub 1}C{sub 3}PYR]Br; N-butyl-N-methylpyrrolidinium, [C{sub 1}C{sub 4}PYR]Br and N-pentyl-N-methylpyrrolidinium bromide, [C{sub 1}C{sub 5}PYR]Br have been synthesized. The structures of new compounds have been confirmed using NMR spectra and elementary analysis. The basic thermal characterization of pure ILs, including temperature and enthalpy of phase transition (T{sub tr}, Δ{sub tr}H), temperature and enthalpy of melting (T{sub m,} Δ{sub m}H) have been measured using a differential scanning microcalorimetry technique (DSC). Decomposition temperature of the tested ILs were detected by the simultaneous TG/DTA experiments. The effect of temperature on the density (ρ) and dynamic viscosity (η) is reported over a wide temperature range from 298.15 to 343.15 K at ambient pressure. From experimental density data, the excess molar volumes (V{sup E}) were calculated and correlated using Redlich–Kister equation. The isothermal vapour–liquid phase equilibria (VLE) have been measured by an ebulliometric method at wide temperature range from 328.15 to 368.15 K and pressure up to 85 kPa. Experimental data have been correlated by means of NRTL equation. The solid–liquid phase equilibria (SLE) for the tested binary mixtures have been determined over whole composition range using dynamic method. The NRTL equation using parameters

  2. Electrodeposition of metals from non-aqueous solutions

    International Nuclear Information System (INIS)

    Electrodeposition of metals from non-aqueous solutions is reviewed. Attention is paid mainly to surface morphology of deposits and their adhesion. The major reasons for carrying out electrodeposition in non-aqueous electrolytes (such as conventional organic solvents, ionic liquids and molten salts) are the water and air stability and the wide electrochemical window of these media. The following metals have been electrodeposited and investigated for the last 15 years: aluminum, zinc, silver, palladium, tantalum, zirconium, gadolinium, plutonium, nickel, cobalt, and other alloys.

  3. X-ray absorption microscopy of aqueous samples

    Science.gov (United States)

    Frazer, Brad; Gilbert, Benjamin; De Stasio, Gelsomina

    2002-03-01

    X-ray photoelectron emission microscopy (X-PEEM) is used for numerous applications in surface microchemical analysis of material science and biological specimens. We have reconfigured the MEPHISTO X-PEEM instrument that is installed at the University of Wisconsin Synchrotron Radiation Center to measure true x-ray transmission spectra by converting transmitted photons to photoelectrons via a thin photocathode layer of gold. We have also developed a method by which to introduce aqueous samples into ultrahigh vacuum. Hence x-ray spectroscopy can be performed on biologically relevant elements (such as K, Ca, etc.) in a physiological environment, i.e., in solution. More important, when coupled with X-PEEM imaging this technique may offer the unique and exciting possibility of studying living cells. We present initial x-ray absorption spectra of solutions of aqueous ionic and chelated Ca, with the aim of distinguishing bound and free ionic calcium in vivo.

  4. Microscopic Insights into the Electrochemical Behavior of Non-aqueous Electrolytes in Supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Deen [ORNL; Wu, Jianzhong [ORNL

    2013-01-01

    Electric double-layer capacitors (EDLC) are electrical devices that store energy by adsorption of ionic species at the inner surface of porous electrodes. Compared with aqueous electrolytes, ionic liquid and organic electrolytes have the advantage of larger potential windows, making them attractive for the next generation of EDLC with superior energy and power densities. The performance of both ionic liquid and organic electrolyte EDLC hinges on the judicious selection of the electrode pore size and the electrolyte composition that requires a comprehension of the charging behavior from a microscopic view. In this perspective, we discuss predictions from the classical density functional theory (CDFT) on the dependence of the capacitance on the pore size for ionic-liquid and organic-electrolyte EDLC. CDFT is applicable to electrodes with the pore size ranging from that below the ionic dimensionality to mesoscopic scales, thus unique for investigating the electrochemical behavior of the confined electrolytes for EDLC applications.

  5. Separation of Guanine and Hypoxanthine with Some Ionic Liquids in RP-HPLC

    Directory of Open Access Journals (Sweden)

    J. Zheng

    2006-01-01

    Full Text Available In this paper, guanine and hypoxanthine were separated with four different ionic liquids as additives for the mobile phase using reversed phase high performance liquid chromatography (RP-HPLC. The ionic liquids, 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF4], 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIm][BF4], 1-ethyl-3-methylimidazolium methylsulfate ([EMIm][MS] and 1-octyl-3-methylimidazolium methylsulfate ([OMIm][MS] were used. Guanine and hypoxanthine couldn’t be separated with many different kinds of unadjusted mobile phase, such as aqueous-methanol, aqueous-acetonitrile, etc. In this reason, present study introduced the ionic liquid for separation of guanine and hypoxanthine as an eluent modifier. And the effects of length of alkyl on the imidazolium ring and its counterion, the concentrations of ionic liquid on the retention factor and effect of pH of mobile phase on retention factor of solutes were investigated also. As a result, guanine and hypoxanthine were separated with the mobile phase including ionic liquid and the excellent separations of these sorbats were achieved using 2.0 mM Lˉ1 [OMIm][MS] as the eluent modifier.

  6. Application of ionic liquids based enzyme-assisted extraction of chlorogenic acid from Eucommia ulmoides leaves.

    Science.gov (United States)

    Liu, Tingting; Sui, Xiaoyu; Li, Li; Zhang, Jie; Liang, Xin; Li, Wenjing; Zhang, Honglian; Fu, Shuang

    2016-01-15

    A new approach for ionic liquid based enzyme-assisted extraction (ILEAE) of chlorogenic acid (CGA) from Eucommia ulmoides is presented in which enzyme pretreatment was used in ionic liquids aqueous media to enhance extraction yield. For this purpose, the solubility of CGA and the activity of cellulase were investigated in eight 1-alkyl-3-methylimidazolium ionic liquids. Cellulase in 0.5 M [C6mim]Br aqueous solution was found to provide better performance in extraction. The factors of ILEAE procedures including extraction time, extraction phase pH, extraction temperatures and enzyme concentrations were investigated. Moreover, the novel developed approach offered advantages in term of yield and efficiency compared with other conventional extraction techniques. Scanning electronic microscopy of plant samples indicated that cellulase treated cell wall in ionic liquid solution was subjected to extract, which led to more efficient extraction by reducing mass transfer barrier. The proposed ILEAE method would develope a continuous process for enzyme-assisted extraction including enzyme incubation and solvent extraction process. In this research, we propose a novel view for enzyme-assisted extraction of plant active component, besides concentrating on enzyme facilitated cell wall degradation, focusing on improvement of bad permeability of ionic liquids solutions.

  7. Uranium chemistry in blood and aqueous media. Techniques of studies

    International Nuclear Information System (INIS)

    The object of this report in a first step, is to understand the chemistry of uranium in aqueous phase by specifying the behavior of this element in function of several parameters such PH, concentration of present species, temperature, ionic force. In a second step, investigation techniques are reviewed: X rays diffraction, potentiometric titrations, polarography, spectrophotometry, NMR of 13C, 31P, 17O, capillary electrophoresis, laser detection. The third part brings elements to understand the uranium complexation in blood medium

  8. Bespoke cationic nano-objects via RAFT aqueous dispersion polymerisation

    OpenAIRE

    Williams, M.; Penfold, NJW; Lovett, JR; Warren, NJ; Douglas, CWI; Doroshenko, N; Verstraete, P; Smets, J; Armes, SP

    2016-01-01

    A range of cationic diblock copolymer nanoparticles are synthesised via polymerisation-induced self-assembly (PISA) using a RAFT aqueous dispersion polymerisation formulation. The cationic character of these nanoparticles can be systematically varied by utilising a binary mixture of two macro-CTAs, namely non-ionic poly(glycerol monomethacrylate) (PGMA) and cationic poly[2-(methacryloyloxy)ethyl]trimethylammonium chloride (PQDMA), with poly(2-hydroxypropyl methacrylate) (PHPMA) being selected...

  9. Efficient separation of transition metals from rare earths by an undiluted phosphonium thiocyanate ionic liquid.

    Science.gov (United States)

    Rout, Alok; Binnemans, Koen

    2016-06-21

    The ionic liquid trihexyl(tetradecyl)phosphonium thiocyanate has been used for the extraction of the transition metal ions Co(ii), Ni(ii), Zn(ii), and the rare-earth ions La(iii), Sm(iii) and Eu(iii) from aqueous solutions containing nitrate or chloride salts. The transition metal ions showed a high affinity for the ionic liquid phase and were efficiently extracted, while the extraction efficiency of the rare-earth ions was low. This difference in extraction behavior enabled separation of the pairs Co(ii)/Sm(iii), Ni(ii)/La(iii) and Zn(ii)/Eu(iii). These separations are relevant for the recycling of rare earths and transition metals from samarium cobalt permanent magnets, nickel metal hydride batteries and lamp phosphors, respectively. The extraction of metal ions from a chloride or nitrate solution with a thiocyanate ionic liquid is an example of "split-anion extraction", where different anions are present in the aqueous and ionic liquid phase. Close to 100% loading was possible for Co(ii) and Zn(ii) up to a concentration of 40 g L(-1) of the transition metal salt in the initial aqueous feed solution, whereas the extraction efficiency for Ni(ii) gradually decreased with increase in the initial feed concentration. Stripping of Co(ii), Zn(ii) and Ni(ii) from the loaded ionic liquid phase was possible by a 15 wt% NH3 solution. The ionic liquid could reused after extraction and stripping. PMID:27243450

  10. A study of redox kinetic in silicate melt

    International Nuclear Information System (INIS)

    The aim of this thesis is to understand better iron redox reactions and mechanisms in silicate glasses and melts. Particular interest has been paid to the influence of temperature and chemical composition. For this purpose, the influence of alkali element content, iron content and network formers on the kinetics of redox reactions has been determined through XANES and Raman spectroscopy experiments performed either near the glass transition or above the liquidus temperature. As a complement, electrical conductivity and RBS spectroscopy experiments have been made to characterize the diffusivity of the species that transport electrical charges and the reaction morphology, respectively. Temperature and composition variations can induce changes in the dominating redox mechanism. At a given temperature, the parameters that exert the strongest influence on redox mechanisms are the presence or lack of divalent cations and the existing decoupling between the mobility of network former and modifier elements. Near Tg, the diffusion of divalent cations, when present in the melt, controls the kinetics of iron redox reactions along with a flux of electron holes. Composition, through the degree of polymerization and the silicate network structure, influences the kinetics and the nature of the involved cations, but not the mechanisms of the reaction. Without alkaline earth elements, the kinetics of redox reactions are controlled by the diffusion of oxygen species. With increasing temperatures, the diffusivities of all ionic species tend to become similar. The decoupling between ionic fluxes then is reduced so that several mechanisms become kinetically equivalent and can thus coexist. (author)

  11. Structure of cyano-anion ionic liquids: X-ray scattering and simulations.

    Science.gov (United States)

    Dhungana, Kamal B; Faria, Luiz F O; Wu, Boning; Liang, Min; Ribeiro, Mauro C C; Margulis, Claudio J; Castner, Edward W

    2016-07-14

    Ionic liquids with cyano anions have long been used because of their unique combination of low-melting temperatures, reduced viscosities, and increased conductivities. Recently we have shown that cyano anions in ionic liquids are particularly interesting for their potential use as electron donors to excited state photo-acceptors [B. Wu et al., J. Phys. Chem. B 119, 14790-14799 (2015)]. Here we report on bulk structural and quantum mechanical results for a series of ionic liquids based on the 1-ethyl-3-methylimidazolium cation, paired with the following five cyano anions: SeCN(-), SCN(-), N(CN)2 (-), C(CN)3 (-), and B(CN)4 (-). By combining molecular dynamics simulations, high-energy X-ray scattering measurements, and periodic boundary condition DFT calculations, we are able to obtain a comprehensive description of the liquid landscape as well as the nature of the HOMO-LUMO states for these ionic liquids in the condensed phase. Features in the structure functions for these ionic liquids are somewhat different than the commonly observed adjacency, charge-charge, and polarity peaks, especially for the bulkiest B(CN)4 (-) anion. While the other four cyano-anion ionic liquids present an anionic HOMO, the one for Im2,1 (+)/B(CN)4 (-) is cationic.

  12. Structure of cyano-anion ionic liquids: X-ray scattering and simulations

    Science.gov (United States)

    Dhungana, Kamal B.; Faria, Luiz F. O.; Wu, Boning; Liang, Min; Ribeiro, Mauro C. C.; Margulis, Claudio J.; Castner, Edward W.

    2016-07-01

    Ionic liquids with cyano anions have long been used because of their unique combination of low-melting temperatures, reduced viscosities, and increased conductivities. Recently we have shown that cyano anions in ionic liquids are particularly interesting for their potential use as electron donors to excited state photo-acceptors [B. Wu et al., J. Phys. Chem. B 119, 14790-14799 (2015)]. Here we report on bulk structural and quantum mechanical results for a series of ionic liquids based on the 1-ethyl-3-methylimidazolium cation, paired with the following five cyano anions: SeCN-, SCN-, N(CN) 2 -, C(CN) 3 -, and B(CN) 4 -. By combining molecular dynamics simulations, high-energy X-ray scattering measurements, and periodic boundary condition DFT calculations, we are able to obtain a comprehensive description of the liquid landscape as well as the nature of the HOMO-LUMO states for these ionic liquids in the condensed phase. Features in the structure functions for these ionic liquids are somewhat different than the commonly observed adjacency, charge-charge, and polarity peaks, especially for the bulkiest B(CN) 4 - anion. While the other four cyano-anion ionic liquids present an anionic HOMO, the one for Im2,1 +/B(CN) 4 - is cationic.

  13. Copper(I)-containing ionic liquids for high-rate electrodeposition

    OpenAIRE

    Brooks, Neil; Schaltin, Stijn; Van Hecke, Kristof; Van Meervelt, Luc; Binnemans, Koen; Fransaer, Jan

    2011-01-01

    New metal-containing ionic liquids [Cu(CH3CN)n][Tf2N] (n = 2, 4; Tf2N = bis(trifluoromethylsulfonyl)amide) have been synthesised and used as a non-aqueous electrolyte for the electrodeposition of copper at current densities greater than 25 Adm(-2). The tetrahedral copper(I)-containing cation in [Cu(CH3CN)(4)] [Tf2N] is structurally analogous to quaternary ammonium and phosphonium ionic liquids and overcomes problems of metal solubility and mass transport. Two CH3CN ligands are removed at elev...

  14. Ionic liquids based on S-alkylthiolanium cations and TFSI anion as potential electrolytes

    Institute of Scientific and Technical Information of China (English)

    ZHANG HuanQi; YANG Li; FANG ShaoHua; PENG ChengXin; LUO HongJun

    2009-01-01

    New ionic liquids based on S-alkylthiolanium cations with TFSI anions were synthesized and charac-terized.The physical and electrochemical properties,including melting point,thermal stability,solubil-ity,viscosity,conductivity and electrochemical window,were reported.Relation between these proper-ties and the structure of the cations was discussed.In this series,T4TFSI and T5TFSI have melting points below -60℃,and their conductivities are 2.10 mS/cm and 1.46 mS/cm;their electrochemical windows are 4.1 V and 4.5 V at room temperature.These cyclic alkylthiolanium-based ionic liquids are promising as novel electrolytes in various electrochemical devices,especially under low temperature condition.

  15. Amphiphilic behavior of two phosphonium based ionic liquids.

    Science.gov (United States)

    Mukherjee, Indrajyoti; Mukherjee, Suvasree; Naskar, Bappaditya; Ghosh, Soumen; Moulik, Satya P

    2013-04-01

    Solution and surface chemical behavior of two phosphonium based ionic liquids triisobutyl (methyl) phosphonium tosylate (IL-1) and trihexyl (tetradecyl) phosphonium bis 2,4,4-(trimethylpentyl)phosphinate (IL-2) have been studied. The polar IL-1 is surface active and water soluble, whereas the weakly polar IL-2 is more surface active with very low aqueous solubility. IL-1 does not form micelles but affects the micellization properties of ionic, nonionic, and zwitterionic surfactants more strongly than conventional electrolytes. IL-2 itself forms micelles and mixed micelles with Triton X-100 (TX-100) in aqueous solution. It also forms Langmuir monolayers of liquid expanded type, at the air/water interface. IL-1 can replace water in forming microemulsions with the oil isopropylmyristate (IPM), stabilized by IL-2 (surfactant)+isopropanol (IP as a co-surfactant) like the IL-1/IPM/(IL-2+IP) system. It produces a large monophasic zone in the pseudoternary phase diagram. The thermodynamics of formation of the microemulsions of IL-1 in oil (IPM) have been examined. The dimensions and the polydispersity of the dispersed nano-droplets in the microemulsions have been determined by DLS. The thermal stability of the microemulsion forming systems has also been studied. ILs studied against Sarcoma-180 cell lines have evidenced proficient anti-cancer activity of IL-1 and moderate activity of IL-2. PMID:23317771

  16. Ionic conducting poly-benzimidazoles

    International Nuclear Information System (INIS)

    Over the last years, many research works have been focused on new clean energy systems. Hydrogen fuel cell seems to be the most promising one. However, the large scale development of this technology is still limited by some key elements. One of them is the polymer electrolyte membrane 'Nafion' currently used, for which the ratio performance/cost is too low. The investigations we carried out during this thesis work are related to a new class of ionic conducting polymer, the sulfonated poly-benzimidazoles (sPBI). Poly-benzimidazoles (PBI) are aromatic heterocyclic polymers well-known for their excellent thermal and chemical stability. Ionic conduction properties are obtained by having strong acid groups (sulfonic acid SO3H) on the macromolecular structure. For that purpose, we first synthesized sulfonated monomers. Their poly-condensation with an appropriate non-sulfonated co-monomer yields to sPBI with sulfonation range from 0 to 100 per cent. Three different sPBI structures were obtained, and verified by appropriate analytical techniques. We also showed that the protocol used for the synthesis resulted in high molecular weights polymers. We prepared ionic conducting membrane by casting sPBI solutions on glass plates. Their properties of stability, water swelling and ionic conductivity were investigated. Surprisingly, the behaviour of sPBI was quite different from the other sulfonated aromatic polymers with same amount of SO3H, their stability was much higher, but their water swelling and ionic conductivity were quite low. We attributed these differences to strong ionic interactions between the sulfonic acid groups and the basic benzimidazole groups of our polymers. However, we managed to solve this problem synthesizing very highly sulfonated PBI, obtaining membranes with a good balance between all the properties necessary. (author)

  17. Preparation and Properties of Non-Crosslinked and Ionically Crosslinked Chitosan/Agar Blended Hydrogel Films

    OpenAIRE

    Mahmoud Nasef, Mohamed; Esam A. El-hefian; Saalah, Sariah; Yahaya, Adul Hamid

    2011-01-01

    Hydrogel films of chitosan (Cs) and agar blends of various proportions were prepared using physical solution blending. Some of the obtained films were ionically cross-linked by treatment with calcium chloride solution. The obtained films were characterized by Fourier transform infrared (FTIR) spectroscopy, thermogravimetry analysis (TGA), differential scanning calorimetery (DSC) and universal mechanical tester. The non-crosslinked Cs/agar blended films showed lower water swelling, melting tem...

  18. Exploring gas-phase ionic liquid aggregates by mass spectrometry and computational chemistry

    OpenAIRE

    Gray, Andrew Peter

    2012-01-01

    Ionic liquids (IL) are salts which are liquid at low temperatures, typically with melting points under 100 °C. In recent years ILs have been treated as novel solvents and used in a wide variety of applications such as analytical and separation processes, electrochemical devices and chemical syntheses. The properties of many ILs have been extensively studied; these studies have primarily focused on the investigation of key physical properties including viscosity, density and sol...

  19. Observations on the crystallization of spodumene from aqueous solutions in a hydrothermal diamond-anvil cell

    Science.gov (United States)

    Li, Jianking; Chou, I-Ming; Yuan, Shunda; Burruss, Robert A.

    2013-01-01

    Crystallization experiments were conducted in a new type of hydrothermal diamond-anvil cell (HDAC; type V) using LiAlSi2O6 (S) gel and H2O (W) as starting materials. A total of 21 experiments were performed at temperatures up to 950°C and pressures up to 788 MPa. In the samples with relatively low W/S ratios, many small crystals formed in the melt phase during cooling. In those with high W/S ratios, only a few crystals with smooth surfaces crystallized from the aqueous fluid in the presence of melt droplets, which were gradually consumed during crystal growth, indicating rapid transfer of material from the melt to the crystals through the aqueous fluid. The nucleation of crystals started at 710 (±70)°C and 520 (±80) MPa, and crystal growth ended at 570 (±40)°C and 320 (±90) MPa, with the cooling P-T path within the stability field of spodumene + quartz in the S-W system. The observed linear crystal growth rates in the aqueous phase, calculated by dividing the maximum length of a single crystal by the duration of the entire growth step, were 4.7 × 10−6 and 5.7 × 10−6 cm s−1 for the cooling rates of 0.5 and 1°C min−1, respectively. However, a rapid crystal growth rate of 3.6 × 10−5 cm s−1 in the aqueous fluid was observed when the components were supplied by nearby melt droplets. Our results show that when crystals nucleate in the aqueous fluid instead of the melt phase, there are fewer nuclei formed, and they grow much faster due to the low viscosity of the aqueous fluid, which accelerates diffusion of components for the growth of crystals. Therefore, the large crystals in granitic pegmatite can crystallize directly from aqueous fluids rather than hydrosilicate melt.

  20. High energy supercapattery with an ionic liquid solution of LiClO4.

    Science.gov (United States)

    Yu, Linpo; Chen, George Z

    2016-08-15

    A supercapattery combining an ideally polarized capacitor-like electrode and a battery-like electrode is demonstrated theoretically and practically using an ionic liquid electrolyte containing 1-butyl-1-methylpyrrolidinium tri(pentafluoroethyl)trifluorophosphate (BMPyrrFAP), gamma-butyrolactone (γ-GBL) and LiClO4. The electrochemical deposition and dissolution of lithium metal on a platinum and glass carbon electrode were investigated in this ionic liquid solution. The CVs showed that the fresh electrochemically deposited lithium metal was stable in the electrolyte, which encouraged the investigation of this ionic liquid solution in a supercapattery with a lithium battery negative electrode. The active material counted specific energy of the supercapattery based on a lithium negative electrode and an activated carbon (Act-C) positive electrode could reach 230 W h kg(-1) under a galvanostatic charge-discharge current density of 1 mA cm(-2). The positive electrode material (Act-C) was also investigated by CV, AC impedance, SEM and BET. The non-uniform particle size and micropores dominated porous structure of the Act-C enabled its electric double layer capacitor (EDLC) behavior in the ionic liquid solution. The measured specific capacitance of the Act-C in this ionic liquid solution is higher than the same Act-C in aqueous solution, which indicates the Act-C can also perform well in the ionic liquid electrolyte. PMID:27228429

  1. Supported Ionic Liquid Phase (SILP) Catalysis for the Production of Acetic acid by Methanol Carbonylation

    DEFF Research Database (Denmark)

    Hanning, Christopher William

    The work presented here is focused on the development of a new reaction process. It applies Supported Ionic Liquid Phase (SILP) catalysis to a specific reaction. By reacting methanol and carbon monoxide over a rhodium catalyst, acetic acid can be formed. This reaction is important on a large scale...... industrially, with millions of tonnes of acetic acid being produced annually. Acetic acid is an important precursor for making adhesives, plastics and fabrics. By using the SILP concept we are able to carry out the reaction in a continuous system, allowing a steady production of acetic acid without having...... were no longer classified as ionic liquids due to melting points above 100◦C). The phosphonium salts showed even better activity in the system compared to the ionic liquids. Overall the work has shown that this process for the manufacture of acetic acid is viable industrially. This is backed up...

  2. Electrical Conductivity of Cryolite Melts

    Science.gov (United States)

    Fellner, P.; Grjotheim, K.; Kvande, H.

    1985-11-01

    This paper proposes an equation for the electrical conductivity of multicomponent cryolite-based mixtures. The equation is based on a physical model which assumes that the conductivity is proportional to the number density of the effective electric charges in the melt. The various authors in the available literature show a great discrepancy in conductivity data of cryolite-based melts. The equation based on the physical model enables determination of which set of data is preferable. Special consideration in this respect is given to the influence of magnesium flouride and lithium flouride additions to the melt.

  3. Density Measurements of Na2WO4-WO3-ZnO Melts

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Based on Archimedes principle, the densities of Na2WO4-WO3-ZnO melts at a fixed mole ratio of 3.43 of Na2WO4 to ZnO were measured. The results indicated that there was a linear relationship between the densities and temperatures at a fixed composition. At a fixed temperature, the linear relationship between densities and compositions showed different slop within different composition regions. The reasons were explained in view of ionic composition changes.

  4. Solid–liquid equilibria of binary mixtures of fluorinated ionic liquids†

    Science.gov (United States)

    Teles, Ana Rita R.; Correia, Helga; Maximo, Guilherme J.; Rebelo, Luís P. N.; Freire, Mara G.; Pereiro, Ana B.; Coutinho, João A. P.

    2016-01-01

    Within ionic liquids, fluorinated ionic liquids (FILs) present unique physico-chemical properties and potential applications in several fields. However, the melting point of these neoteric compounds is usually higher due to the presence of fluorine atoms. This drawback may be resolved by, for instance, mixing different FILs to create eutectic mixtures. In this work, binary mixtures of fluoro-containing and fluorinated ionic liquids were considered with the aim of decreasing their melting temperatures as well as understanding and characterizing these mixtures and their phase transitions. Five FILs were selected, allowing the investigation of four binary mixtures, each of them with a common ion. Their solid–liquid and solid–solid equilibria were studied by differential scanning calorimetry and the non-ideality of the mixtures was investigated. Overall, a variety of solid–liquid equilibria with systems exhibiting eutectic behavior, polymorphs with solid–solid phase transitions, and the formation of intermediate compounds and solid solutions were surprisingly found. In addition to these intriguing behaviours, novel FILs with lower melting temperatures were obtained by the formation of binary systems, thus enlarging the application range of FILs at lower temperatures. PMID:27603428

  5. Solid-liquid equilibria of binary mixtures of fluorinated ionic liquids.

    Science.gov (United States)

    Teles, Ana Rita R; Correia, Helga; Maximo, Guilherme J; Rebelo, Luís P N; Freire, Mara G; Pereiro, Ana B; Coutinho, João A P

    2016-09-28

    Within ionic liquids, fluorinated ionic liquids (FILs) present unique physico-chemical properties and potential applications in several fields. However, the melting point of these neoteric compounds is usually higher due to the presence of fluorine atoms. This drawback may be resolved by, for instance, mixing different FILs to create eutectic mixtures. In this work, binary mixtures of fluoro-containing and fluorinated ionic liquids were considered with the aim of decreasing their melting temperatures as well as understanding and characterizing these mixtures and their phase transitions. Five FILs were selected, allowing the investigation of four binary mixtures, each of them with a common ion. Their solid-liquid and solid-solid equilibria were studied by differential scanning calorimetry and the non-ideality of the mixtures was investigated. Overall, a variety of solid-liquid equilibria with systems exhibiting eutectic behavior, polymorphs with solid-solid phase transitions, and the formation of intermediate compounds and solid solutions were surprisingly found. In addition to these intriguing behaviours, novel FILs with lower melting temperatures were obtained by the formation of binary systems, thus enlarging the application range of FILs at lower temperatures.

  6. Fabrication of ionic liquid electrodeposited Cu--Sn--Zn--S--Se thin films and method of making

    Science.gov (United States)

    Bhattacharya, Raghu Nath

    2016-01-12

    A semiconductor thin-film and method for producing a semiconductor thin-films comprising a metallic salt, an ionic compound in a non-aqueous solution mixed with a solvent and processing the stacked layer in chalcogen that results in a CZTS/CZTSS thin films that may be deposited on a substrate is disclosed.

  7. Ionic liquids. A new class of lubricants with unusual properties; Ionische Fluessigkeiten. Eine neue Klasse von Schmierstoffen mit ungewoehnlichen Eigenschaften

    Energy Technology Data Exchange (ETDEWEB)

    Kalb, Roland Stefan

    2008-07-15

    Ionic liquids are low melting, organic salts with unusual physical and chemical properties. The complete technological potential of these materials is not foreseeable yet. Within the range of lubricants, some promising publications have appeared. The author of the contribution under consideration reports on the successful, custom-made use of the fascinating material properties of ionic liquids on the basis of the development of a compressor with liquid pistons for Linde AG. From the view of the author, ionic liquids can be used as additives in metalworking, transformation as well as to wear protections in gear transmissions and bearings. As liquid solid lubricants, ionic liquids can be used in high vacuum, at extreme temperatures, for the life span lubrication of difficulty accessible components, for the life span lubrication of sinter sliding bearings.

  8. Gaseous Hydrocarbon Separations Using Functionalized Ionic Liquids

    OpenAIRE

    Moura Leila; Santini Catherine C.; Costa Gomes Margarida F.

    2016-01-01

    The functionalization of the side chains on the cation or the anion of an ionic liquid is a common approach to tailor its properties for different processes including the separation of gases. In this paper, we present the current state of the art concerning the usage of ionic liquids for hydrocarbon separations. We also show how the functionalization of ionic liquids or the appropriate anion/cation combinations can contribute to the increase of the performance of the ionic liquids for the sep...

  9. Application of Ionic Liquids in Hydrometallurgy

    OpenAIRE

    Jesik Park; Yeojin Jung; Priyandi Kusumah; Jinyoung Lee; Kyungjung Kwon; Churl Kyoung Lee

    2014-01-01

    Ionic liquids, low temperature molten salts, have various advantages manifesting themselves as durable and environmentally friendly solvents. Their application is expanding into various fields including hydrometallurgy due to their unique properties such as non-volatility, inflammability, low toxicity, good ionic conductivity, and wide electrochemical potential window. This paper reviews previous literatures and our recent results adopting ionic liquids in extraction, synthesis and processing...

  10. Ionic-Liquid-Tethered Nanoparticles: Hybrid Electrolytes

    KAUST Repository

    Moganty, Surya S.

    2010-10-22

    A new class of solventless electrolytes was created by tethering ionic liquids to hard inorganic ZrO2 nanostructures (see picture; NIM=nanoscale ionic material). These hybrid fluids exhibit exceptional redox stability windows, excellent thermal stability, good lithium transference numbers, long-term interfacial stability in the presence of a lithium anode and, when doped with lithium salt, reasonable ionic conductivities.

  11. The hype with ionic liquids as solvents

    Science.gov (United States)

    Kunz, Werner; Häckl, Katharina

    2016-09-01

    In this mini review, we give our personal opinion about the present state of the art concerning Ionic Liquids, proposed as alternative solvents. In particular, we consider their different drawbacks and disadvantages and discuss the critical aspects of the research of Ionic Liquids as solvents. Finally, we point out some aspects on potentially promising Ionic Liquid solvents.

  12. Catalysis in Molten Ionic Media

    DEFF Research Database (Denmark)

    Boghosian, Soghomon; Fehrmann, Rasmus

    2013-01-01

    This chapter deals with catalysis in molten salts and ionic liquids, which are introduced and reviewed briefly, while an in-depth review of the oxidation catalyst used for the manufacturing of sulfuric acid and cleaning of flue gas from electrical power plants is the main topic of the chapter...

  13. Lipid processing in ionic liquids

    DEFF Research Database (Denmark)

    Lue, Bena-Marie; Guo, Zheng; Xu, Xuebing

    2007-01-01

    Ionic liquids (ILs) have been touted as “green” alternatives to traditional molecular solvents and have many unique properties which make them extremely desirable substitutes. Among their most attractive properties are their lack of vapour pressure, broad liquid range, strong solvating power...

  14. The attenuation of oscillatory thermocapillary convection in the oxide melt by a transverse magnetic field

    Institute of Scientific and Technical Information of China (English)

    JIN WeiQing; AI Fei; HONG Yong; LUO HaoSu; LIU Yan; PAN XiuHong

    2007-01-01

    The effect of a transverse magnetic field on the oscillatory thermocapillary convection in the NaBi(WO4)2 melt was studied by using the in-situ observation system. The oscillation was attenuated when the 60 mT magnetic field was applied, as shown by the decrease in the amplitude and the frequency. Furthermore, the oscillation under smaller temperature difference was stabilized after the magnetic field was applied. The magnetic effect could be due to the Lorentz force generated by the interaction between motional ions and the vertical magnetic field. The ionic conductivities were measured to demonstrate the effect of the magnetic field. The solid ionic electrical conductivity increases with the temperature rise, and the melt ionic electrical conductivity was measured to be about 2.0×10-4 Ω-1·cm-1. Experimental results manifest that the effect of the magnetic field on anions and cations in the melt makes the flow change to the direction normal to the applied field, so the flow is more orderly and the oscillation is suppressed.

  15. Scaleable Clean Aluminum Melting Systems

    Energy Technology Data Exchange (ETDEWEB)

    Han, Q.; Das, S.K. (Secat, Inc.)

    2008-02-15

    The project entitled 'Scaleable Clean Aluminum Melting Systems' was a Cooperative Research and Development Agreements (CRADAs) between Oak Ridge National Laboratory (ORNL) and Secat Inc. The three-year project was initially funded for the first year and was then canceled due to funding cuts at the DOE headquarters. The limited funds allowed the research team to visit industrial sites and investigate the status of using immersion heaters for aluminum melting applications. Primary concepts were proposed on the design of furnaces using immersion heaters for melting. The proposed project can continue if the funding agency resumes the funds to this research. The objective of this project was to develop and demonstrate integrated, retrofitable technologies for clean melting systems for aluminum in both the Metal Casting and integrated aluminum processing industries. The scope focused on immersion heating coupled with metal circulation systems that provide significant opportunity for energy savings as well as reduction of melt loss in the form of dross. The project aimed at the development and integration of technologies that would enable significant reduction in the energy consumption and environmental impacts of melting aluminum through substitution of immersion heating for the conventional radiant burner methods used in reverberatory furnaces. Specifically, the program would couple heater improvements with furnace modeling that would enable cost-effective retrofits to a range of existing furnace sizes, reducing the economic barrier to application.

  16. Laser melting of uranium carbides

    Science.gov (United States)

    Utton, C. A.; De Bruycker, F.; Boboridis, K.; Jardin, R.; Noel, H.; Guéneau, C.; Manara, D.

    2009-03-01

    In the context of the material research aimed at supporting the development of nuclear plants of the fourth Generation, renewed interest has recently arisen in carbide fuels. A profound understanding of the behaviour of nuclear materials in extreme conditions is of prime importance for the analysis of the operation limits of nuclear fuels, and prediction of possible nuclear reactor accidents. In this context, the main goal of the present paper is to demonstrate the feasibility of laser induced melting experiments on stoichiometric uranium carbides; UC, UC1.5 and UC2. Measurements were performed, at temperatures around 3000 K, under a few bars of inert gas in order to minimise vaporisation and oxidation effects, which may occur at these temperatures. Moreover, a recently developed investigation method has been employed, based on in situ analysis of the sample surface reflectivity evolution during melting. Current results, 2781 K for the melting point of UC, 2665 K for the solidus and 2681 K for the liquidus of U2C3, 2754 K for the solidus and 2770 K for the liquidus of UC2, are in fair agreement with early publications where the melting behaviour of uranium carbides was investigated by traditional furnace melting methods. Further information has been obtained in the current research about the non-congruent (solidus-liquidus) melting of certain carbides, which suggest that a solidus-liquidus scheme is followed by higher ratio carbides, possibly even for UC2.

  17. Exploiting donor-acceptor interactions in aqueous dynamic combinatorial libraries : exploratory studies of simple systems

    NARCIS (Netherlands)

    Au-Yeung, Ho Yu; Cougnon, Fabien B. L.; Otto, Sijbren; Pantos, G. Dan; Sanders, Jeremy K. M.; Pantoş, G. Dan

    2010-01-01

    The behaviour of aqueous dynamic combinatorial libraries (DCLs) containing either electron-rich donor building blocks based on dioxynaphthalene (DN), or electron-deficient acceptor building blocks based on naphthalenediimide (NDI) are described. The influence of concentration and ionic strength on l

  18. Recovery of sugars from ionic liquid biomass liquor by solvent extraction

    Energy Technology Data Exchange (ETDEWEB)

    Brennan, Timothy Charles R.; Holmes, Bradley M.; Simmons, Blake A.; Blanch, Harvey W.

    2015-10-13

    The present invention provides for a composition comprising a solution comprising (a) an ionic liquid (IL) or ionic liquid-aqueous (ILA) phase and (b) an organic phase, wherein the solution comprises a sugar and a boronic acid. The present invention also provides for a method of removing a sugar from a solution, comprising: (a) providing a solution comprising (i) an IL or ILA phase and (ii) an organic phase, wherein the solution comprises an IL, a sugar and a boronic acid; (b) contacting the sugar with the boronic acid to form a sugar-boronic acid complex, (c) separating the organic phase and the aqueous phase, wherein the organic phase contains the sugar-boronic acid complex, and optionally (d) separating the sugar from the organic phase.

  19. Aggregation behavior and total miscibility of fluorinated ionic liquids in water.

    Science.gov (United States)

    Pereiro, Ana B; Araújo, João M M; Teixeira, Fabiana S; Marrucho, Isabel M; Piñeiro, Manuel M; Rebelo, Luis Paulo N

    2015-02-01

    In this work, novel and nontoxic fluorinated ionic liquids (FILs) that are totally miscible in water and could be used in biological applications, where fluorocarbon compounds present a handicap because their aqueous solubility (water and biological fluids) is in most cases too low, have been investigated. The self-aggregation behavior of perfluorosulfonate-functionalized ionic liquids in aqueous solutions has been characterized using conductometric titration, isothermal titration calorimetry (ITC), surface tension measurements, dynamic light scattering (DLS), viscosity and density measurements, and transmission electron microscopy (TEM). Aggregation and interfacial parameters have been computed by conductimetry, calorimetry, and surface tension measurements in order to study various thermodynamic and surface properties that demonstrate that the aggregation process is entropy-driven and that the aggregation process is less spontaneous than the adsorption process. The novel perfluorosulfonate-functionalized ILs studied in this work show improved surface activity and aggregation behavior, forming distinct self-assembled structures.

  20. Dy(OTf)3 Catalyzed Reaction of Indole with Aldehydes and Ketones in Ionic Liquids

    Institute of Scientific and Technical Information of China (English)

    MI Xue-Ling; LUO San-Zhong; HE Jia-Qi; CHENG Jin-Pei

    2003-01-01

    @@ The use of environmentally benign reaction media is very important in view of today' s environmentally con scious attitude. In connect with this, room temperature ionic liquids that are air and moisture stable have received a good deal of attention in recent years as novel solvent systems for organic synthesis. A number of reactions such as Friedel-Crafts reactions, Diels-Alder cycloadditions, hydrogenations, and Heck reactions have employed ionic liquids as solvents. Among them, the Friedel-Crafts reaction[1] is of great synthetic significance in view of laboratory synthesis and industrial production. Recent studies showed that Friedel-Crafts reaction of indole with carbonyl compounds proceeded readily in aqueous media. [2] However, the aqueous reactions suffer from some common problems,such as tedious work-up, reuse of catalyst and so on.

  1. Activation and stabilization of enzymes in ionic liquids.

    Science.gov (United States)

    Moniruzzaman, Muhammad; Kamiya, Noriho; Goto, Masahiro

    2010-06-28

    As environmentally benign "green" solvents, room temperature ionic liquids (ILs) have been used as solvents or (co)solvents in biocatalytic reactions and processes for a decade. The technological utility of enzymes can be enhanced greatly by their use in ionic liquids (ILs) rather than in conventional organic solvents or in their natural aqueous reaction media. In fact, the combination of green properties and unique tailor-made physicochemical properties make ILs excellent non-aqueous solvents for enzymatic catalysis with numerous advantages over other solvents, including high conversion rates, high selectivity, better enzyme stability, as well as better recoverability and recyclability. However, in many cases, particularly in hydrophilic ILs, enzymes show relative instability and/or lower activity compared with conventional solvents. To improve the enzyme activity as well as stability in ILs, various attempts have been made by modifying the form of the enzymes. Examples are enzyme immobilization onto support materials via adsorption or multipoint attachment, lyophilization in the presence of stabilizing agents, chemical modification with stabilizing agents, formation of cross-linked enzyme aggregates, pretreatment with polar organic solvents or enzymes combined with suitable surfactants to form microemulsions. The use of these enzyme preparations in ILs can dramatically increase the solvent tolerance, enhance activity as well as stability, and improve enantioselectivity. This perspective highlights a number of pronounced strategies being used successfully for activation and stabilization of enzymes in non-aqueous ILs media. This review is not intended to be comprehensive, but rather to present a general overview of the potential approaches to activate enzymes for diverse enzymatic processes and biotransformations in ILs. PMID:20445940

  2. Binary coalescence of gas bubbles in the presence of a non-ionic surfactant.

    Science.gov (United States)

    Duerr-Auster, N; Gunde, R; Mäder, R; Windhab, Erich J

    2009-05-15

    The coalescence behavior of air bubbles in a dilute aqueous surfactant solution of a polyglycerol fatty acid ester (PGE), a commercial non-ionic surfactant, is investigated in a binary coalescence experiment. The focus is on the influence of the ionic strength of the solution on the rate of coalescence. Results are compared with the adsorption kinetics and surface shear/dilatational rheological properties of the surfactant. Experiments show that the coalescence frequency is significantly lower at low ionic strength, and that bubble stability increases with increasing aging time. Stabilization occurs via surfactant adsorption and a resulting electrostatic and/or steric repulsive force. The electrostatic force presumably originates from small amounts of anionic fatty acid soaps, which are residues from the industrial synthesis. The steric force can be related to the adsorption of visco-elastic layers of PGE at the air-water interface. PMID:19200557

  3. Quality Control of 1-Alkyl-3-methylimidazolium Ionic Liquid Precursors with HPLC

    Institute of Scientific and Technical Information of China (English)

    张延强; 张建敏; 陈玉涣; 张锁江

    2007-01-01

    A high performance liquid chromatography (HPLC) method was proposed to monitor the synthesis and purification of the 1-alkyl-3-methylimidazolium ionic liquid precursors from alkylation of 1-methylimidazole with alkyl halides and determine the purity of final products. The results showed that separation of 1-methylimidazole from the precursors could be obtained under the HPLC performance conditions such as cation exchange column, acetonitrile/KH2PO4 aqueous solution and 209 nm wavelength. The content of unreacted 1-methylimidazole in the precursors could be easily calculated from their corresponding HPLC peak areas with the calibration curve of 1-methylimidazole. The retention times of the 1-alkyl-3-methylimidazolium ionic liquid precursors decreased with their increasing alkyls, and the ionic liquids with the same cation and different anions had almost the same retention times.

  4. Temperature-Driven Mixing-Demixing Behavior of Binary Mixtures of the Ionic Liquid Choline Bis(trifluoromethylsulfonyl)imide and Water

    OpenAIRE

    Nockemann, Peter; Binnemans, Koen; Thijs, Ben; Parac-Vogt, Tatjana; Merz, Klaus; Mudring, Anja-Verena; Menon, Preethy Chirukandath; Rajesh, Ravindran Nair; George, Cordoyiannis; Thoen, Jan; Leys, Jan; Glorieux, Christ

    2009-01-01

    The ionic liquid (2-hydroxyethylammonium)trimethylammonium) bis(trifluoromethylsulfonyl)imide (choline bistriflimide) was obtained as a supercooled liquid at room temperature (melting point = 30 °C). Crystals of choline bistriflimide suitable for structure determination were grown from the melt in situ on the X-ray diffractometer. The choline cation adopts a folded conformation, whereas the bistriflimide anion exhibits a transoid conformation. The choline cation and the bistriflimide anion ar...

  5. Comparable Stability of Hoogsteen and Watson–Crick Base Pairs in Ionic Liquid Choline Dihydrogen Phosphate

    OpenAIRE

    Hisae Tateishi-Karimata; Miki Nakano; Naoki Sugimoto

    2014-01-01

    The instability of Hoogsteen base pairs relative to Watson–Crick base pairs has limited biological applications of triplex-forming oligonucleotides. Hydrated ionic liquids (ILs) provide favourable environments for a wide range of chemical reactions and are known to impact the stabilities of Watson–Crick base pairs. We found that DNA triplex formation was significantly stabilized in hydrated choline dihydrogen phosphate as compared with an aqueous buffer at neutral pH. Interestingly, the stabi...

  6. Electrodeposition of black chromium from CR(III) ionic liquid solution

    OpenAIRE

    Eugénio, S.; Rangel, C. M.; Vilar, Rui

    2009-01-01

    Black chromium is an important coating material used in solar thermal systems as a spectrally selective surface. This coating is usually obtained by electrodeposition from sulphate free chromium (VI) aqueous solutions which represent a health and environmental hazard due to the presence of Cr(VI), a known toxic and carcinogenic agent. Recent developments in green chemistry have shown that ionic liquids can be used as electrolytes, allowing the deposition of a wide range of materials with negl...

  7. The ionic product of water in highly concentrated sodium perchlorate solutions.

    Science.gov (United States)

    Turonek, M L; Hefter, G T; May, P M

    1998-03-01

    The ionic product of water, pK(w)=-log[H(+)][OH(-)], has been determined in aqueous solutions of sodium perchlorate over the concentration range of 1.0-8.0 M at 25 degrees C from high-precision potentiometric titrations carried out in cells with liquid junction using both glass and hydrogen electrodes. The glass electrode results are systematically lower probably as a result of interference by Na(+) ions.

  8. Characterization of Interactions of Hydroxyethylcellulose Derivatives in the Presence of Ionic Surfactants or with Cyclodextrin Monomers

    OpenAIRE

    2006-01-01

    In this work, Structural, dynamical, and rheological properties of aqueous solutions of hydroxyethylcellulose (HEC) derivatives in the presence of ionic surfactants or with cyclodextrin monomers have been investigated. The discussion about these systems has been divided into three parts. In the first part anionic hydroxyethylcellulose (HEC(-)) or its unmodified analogue in the presence of an anionic surfactant (SDS) or a cationic surfactant (CTAB or Gemini) is considered. Weak interactions be...

  9. Pre-concentration and determination of amitriptyline residues in waste water by ionic liquid based immersed droplet microextraction and HPLC

    Institute of Scientific and Technical Information of China (English)

    M.T. Hamed Mosavian; Z. Es'haghi; N. Razavi; S. Banihashemi

    2012-01-01

    This paper describes a new approach for the determination of amitriptyline in wastewater by ionic liquid based immersed droplet microextraction (IL-IDME) prior to highperformance liquid chromatography with ultraviolet detection. 1-Hexyl-3-methylimidazolium hexafluorophosphate ([C6MIM][PF6]) was used as an ionic liquid. Various factors that affect extraction, such as volume of ionic liquid, stirring rate, extraction time, pH of the aqueous solution and salting effect, were optimized. The optimal conditions were as follows: microextraction time, 10 min; stirring rate, 720 rpm; pH, 11; ionic drop volume, 100 uL; and no sodium chloride addition. In quantitative experiments the method showed linearity in a range from 0.01 to 10 ug/mL, a limit of detection of 0.004 ug/mL and an excellent pre-concentration factor (PF) of 1100. Finally, the method was successfully applied to the determination of amitriptyline in the hospital wastewater samples.

  10. Nanopatterned Protein Films Directed by Ionic Complexation with Water-Soluble Diblock Copolymers.

    Science.gov (United States)

    Kim, Bokyung; Lam, Christopher N; Olsen, Bradley D

    2012-06-12

    The use of ionic interactions to direct both protein templating and block copolymer self-assembly into nanopatterned films with only aqueous processing conditions is demonstrated using block copolymers containing both thermally responsive and pH responsive blocks. Controlled reversible addition-fragmentation chain-transfer (RAFT) polymerization is employed to synthesize poly(N-isopropylacrylamide-b-2-(dimethylamino)ethyl acrylate) (PNIPAM-b-PDMAEA) diblock copolymers. The pH-dependent ionic complexation between the fluorescent protein, mCherry, and the ionic PDMAEA block is established using dynamic light scattering (DLS) and UV-Vis spectroscopy. DLS shows that the size of the resulting coacervate micelles depends strongly on pH, while UV-Vis spectroscopy shows a correlation between the protein's absorption maximum and the ionic microenvironment. Zeta potential measurements clearly indicate the ionic nature of the complex-forming interactions. Spin casting was used to prepare nanostructured films from the protein-block copolymer coacervates. After film formation, the lower critical solution temperature (LCST) of the PNIPAM blocks allows the nanomaterial to be effectively immobilized in aqueous environments at physiological temperatures, enabling potential use as a controlled protein release material or polymer matrix for protein immobilization. At pH 9.2 and 7.8, the release rates are at least 10 times faster than that at pH 6.4 due to weaker interaction between protein and PNIPAM-b-PDMAEA (PND) diblock copolymer. Due to the ionic environment in which protein is confined, the majority of the protein (80%) remains active, independent of pH, even after having been dehydrated in vacuum and confined in the films. PMID:24904186

  11. NOVEL FISSION PRODUCT SEPARATION BASED ON ROOM-TEMPERATURE IONIC LIQUIDS

    Energy Technology Data Exchange (ETDEWEB)

    Hussey, Charles L.

    2004-06-01

    The DoE/NE underground storage tanks at Hanford, SRS, and INEEL contain liquid wastes with high concentrations of radioactive species, mainly 137Cs and 90Sr. Because the other components of the liquid waste are mainly sodium nitrate and sodium hydroxide, most of this tank waste can be treated inexpensively as low-level waste if 137Cs and 90Sr can be selectively removed. Many ionophores (crown ether and calixarene compounds) have been synthesized for the purpose of selectively extracting Cs+ and Sr2+ from an aqueous phase into an immiscible organic phase. Recent studies conducted at ORNL1,2 reveal that hydrophobic ionic liquids might be better solvents for extracting metal ions from aqueous solutions with these ionophores than conventional immiscible organic solvents, such as benzene, toluene, and dichloromethane, because both Cs+ and Sr2+ exhibit larger distribution coefficients in the ionic liquids. In addition, the vapor pressures of these ionic liquids are insignificant. Thus, there is little or no vaporization loss of these solvents. Most of the ionic liquids under investigation are relatively nontoxic compared to the hydrocarbon solvents that they replace, classifying them as ''green'' solvents.

  12. Prediction of the zeta potentials and ionic descriptors of a silica hydride stationary phase with mobile phases of different pH and ionic strength.

    Science.gov (United States)

    Kulsing, Chadin; Yang, Yuanzhong; Matyska, Maria T; Pesek, Joseph J; Boysen, Reinhard I; Hearn, Milton T W

    2015-02-15

    In this study, the zeta potentials of a silica hydride stationary phase (Diamond Hydride™) in the presence of different water-acetonitrile mixtures (from 0-80% (v/v) acetonitrile) of different ionic strengths (from 0-40mM) and pH values (from pH 3.0-7.0) have been investigated. Debye-Hückel theory was applied to explain the effect of changes in the pH and ionic strength of these aqueous media on the negative zeta potential of this stationary phase. The experimental zeta potentials of the Diamond Hydride™ particles as a function of acetonitrile content up to 50% (v/v) correlated (R(2)=0.998) with the predicted zeta potential values based on this established theory, when the values of the dissociation constant of all related species, as well as viscosity, dielectric constant and refractive index of the aqueous medium were taken into consideration. Further, the retention behavior of basic, acidic and neutral analytes was investigated under mobile phase conditions of higher pH and lower ionic strength. Under these conditions, the Diamond Hydride™ stationary phase surface became more negative, as assessed from the increasingly more negative zeta potentials, resulting in the ion exchange characteristics becoming more dominant and the basic analytes showing increasing retention. Ionic descriptors were derived from these chromatographic experiments based on the assumption that linear solvation energy relationships prevail. The results were compared with predicted ionic descriptors based on the different calculated zeta potential values resulting in an overall correlation of R(2)=0.888. These studies provide fundamental insights into the impact on the separation performance of changes in the zeta potential of the Diamond Hydride™ surface with the results relevant to other silica hydride and, potentially, to other types of stationary phase materials.

  13. Computer simulation of ionic conduction in ZrF4-BaF2 glass

    International Nuclear Information System (INIS)

    Molecular dynamics simulations are performed for a ZrF4-BaF2 glass system, which is expected to be a good ion-conducting material, in order to investigate the fundamental conduction dynamics of fluoride ions in the glass. The simulation results show that the ionic conduction is governed by crystal is discussed. This is clearly different from the diffusive motion observed in the melt. It is also found that the mobility is clearly different between bridging (Zr-F-Zr) and non-bridging (Zr-F-(Ba), (Ba)-F-(Ba)) fluoride ions in both glass and melt. The present result gives a satisfactory explanation of two distinct time scales observed in a previous NMR measurement (Y. Kawamoto and J. Fujiwara, 1990 Phys. Chem. Glasses 31 117). The first-passage-time approach is applied to the melt to determine the self-diffusion coefficients of the bridging and the non-bridging fluoride ions separately. (authors)

  14. Nanostructuration Effect on the Thermal Behavior of Ionic Liquids.

    Science.gov (United States)

    Rodrigues, Ana S M C; Santos, Luís M N B F

    2016-05-18

    This work shows how the nanostructuration of ionic liquids (ILs) governs the glass and melting transitions of the bistriflimide imidazolium-based [Cn C1 im][NTf2 ] and [Cn Cn im][NTf2 ] series, which highlights the trend shift that occurs at the critical alkyl size (CAS) of n=6. An initial increase in the glass temperature (Tg ) with an increase in the alkyl side chain was observed due to the intensification of the dispersive interactions (van der Waals). Above the CAS, the -CH2 - increment has the same effect in both glass and liquid states, which leads to a plateau in the glass transition after nanostructuration. The melting temperature (Tm ) of the [Cn C1 im][NTf2 ] and [Cn Cn im][NTf2 ] series presents a V-shaped profile. For the short-alkyl ILs, the -CH2 - increment affects the electrostatic ion pair interactions, which leads to an increase in the conformational entropy. The -CH2 - increment disturbs the packing ability of the ILs and leads to a higher entropy value (ΔslSm○ ) and consequently a decrease in Tm . Above the CAS, the -CH2 - contribution to the melting temperature becomes more regular, as a consequence of the nanostructuration of the IL into polar and nonpolar domains. The dependence of the alkyl chain on the temperature, enthalpy, and entropy of melting in the ILs above the CAS is very similar to the one observed for the alkane series, which highlights the importance of the nonpolar alkyl domains on the ILs thermal behavior.

  15. Immobilization of enzymes using non-ionic colloidal liquid aphrons (CLAs): Surface and enzyme effects.

    Science.gov (United States)

    Ward, Keeran; Xi, Jingshu; Stuckey, David C

    2015-12-01

    The use of non-ionic colloidal liquid aphrons (CLAs) as a support for enzyme immobilisation was investigated. Formulation required the mixing of an aqueous-surfactant solution with a relatively non-polar solvent-surfactant solution, forming a solvent droplet surrounded by a thin stabilised aqueous film (soapy shell). Studies utilising anionic surfactants have showed increased retention, however, very little have been understood about the forces governing immobilisation. This study seeks to determine the effects of enzyme properties on CLA immobilisation by examining a non-ionic/non-polar solvent system comprised of two non-ionic surfactants, Tween 20 and 80, mineral oil and the enzymes lipase, aprotinin and α-chymotrypsin. From these results it was deduced that hydrophobic interactions strongly governed immobilisation. Confocal Scanning Laser Microscopy (CSLM) revealed that immobilisation was predominantly achieved by surface adsorption attributed to hydrophobic interactions between the enzyme and the CLA surface. Enzyme surface affinity was found to increase when added directly to the formulation (pre-manufacture addition), as opposed to the bulk continuous phase (post-manufacture addition), with α-chymotrypsin and aprotinin being the most perturbed, while lipase was relatively unaffected. The effect of zeta potential on immobilisation showed that enzymes adsorbed better closer to their pI, indicating that charge minimisation was necessary for immobilisation. Finally, the effect of increasing enzyme concentration in the aqueous phase resulted in an increase in adsorption for all enzymes due to cooperativity between protein molecules, with saturation occurring faster at higher adsorption rates.

  16. Preparation of Ionic Silsesquioxanes with Regular Structures and Their Hybridization

    Directory of Open Access Journals (Sweden)

    Yoshiro Kaneko

    2012-01-01

    Full Text Available This paper deals with our recent studies on the preparation of ionic silsesquioxanes (SQs with regular structures. Cationic ladder-like polySQs (PSQs with hexagonally stacked structures were successfully prepared by the sol-gel reactions of amino group-containing organotrialkoxysilanes in strong acid aqueous solutions. Self-organization of an ion pair (a salt prepared from the amino group in the organotrialkoxysilane and an acid is the key factor for the formation of such regular structures of the PSQs. It is also reported that the control of the conformational structure of the PSQs was performed by the introduction of the chiral moieties. In addition, we investigated the correlation between the of acid-catalysts and the structures of SQs prepared by the hydrolytic condensation of amino group-containing organotrialkoxysilane, that is, the use of the superacid aqueous solution resulted in the formation of cage-like octaSQ, while the ladder-like PSQs with hexagonally stacked structures were formed from the strong acid aqueous solutions under the same reaction conditions. Furthermore, anion-exchange behaviors of the cationic ladder-like PSQ were investigated with various organic and inorganic compounds, such as anionic surfactants, a polymer, and layered clay minerals, to obtain the functional hybrid materials.

  17. Ionic flotation of strontium 89

    International Nuclear Information System (INIS)

    The experimental results on 89Sr ionic flotation out of sewage after deactivation using sodium dodecylbenzene sulfonate (DBSNa) as a foamer. Strontium was used in the form of SrCl2 at the 1.5-2.0 μCi/l isotopic concentration. It is established that the best condition of 89Sr flotation is the 2.0-2.5 pH range. During ionic flotation interaction of 89Sr microquantities with DBSNa has in the main an ion exchange character. The experimental data satisfactorily obey the equation being a consequence of the law of mass action. The process kinetics can be described by the equation of the first-order reaction

  18. A Novel Inorganic Low Melting Electrolyte for Secondary-Aluminum-Nickel Sulfide Batteries

    DEFF Research Database (Denmark)

    Hjuler, H.A.; Winbrush, S. von; Berg, Rolf W.;

    1989-01-01

    A new, inorganic low melting electrolyte with the composition LiAlCl4-NaAlCl4-NaAlBr4-KAlCl4 (3:2:3:2) [or equivalentlyLiAlBr4-NaAlCl4-KAlCl4 (3:5:2)] has been developed. The melting point for this neutral melt is 86°C; the decompositionpotential is approximately 2.0V; the ionic conductivity...... is measured in the range 97°–401°C and is 0.142s cm–1 at100°C, and the density is 2.07g cm–3. The conductivity seems to be an almost linear combination of the conductivities ofthe four individual halo salts which form the melt. Other examined higher melting mixtures exhibit conductivities deviatingless than...... ±10% from their combination expectations. The low melting electrolyte is employed in the rechargeable batterysystem Al/electrolyte/Ni3S2 at 100°C. The open-circuit voltage of this system is from 0.82 to 1.0V. Dendrite-free aluminumdeposits are obtained. The cycling behavior of the battery system...

  19. Preparation,characterization and properties studies of quinine-imprinted polymer in the aqueous phase

    Institute of Scientific and Technical Information of China (English)

    He Jianfeng; Liu Lan; Yang Guilan; Deng Qinying

    2006-01-01

    The uniform-sized spherical molecularly imprinted polymers were successfully prepared through molecular imprinting technology by two-step seed swelling and mini-emulsion polymerization in the aqueous condition using quinine as template molecules and methacrylic acid (MAA)as functional monomer.The polymers were characterized by IR spectra,thermal-weight analysis,scanning electron microscope and laser particle size analysis.The properties of imprinted polymers were investigated in different organic phases and aqueous media.In the organic media,results suggested that polar interactions(hydrogen bonding,ionic interactions)between acidic monomer/polymer and template molecules are mainly responsible for the binding and recognition;whereas in the aqueous medium,a considerable recognition effect was also obtained where the ionic(electrostatic)interaction and hydrophobic interaction play an important role.The experiments of binding different substrates indicated that the MIPs possessed an excellent rebinding ability and inherent selectivity to quinine.

  20. Ionic liquids for enzymatic sensing

    OpenAIRE

    Fraser, Kevin J.

    2012-01-01

    Point-of-care (POC) glucose biosensors play an important role in the management of blood sugar levels in patients with diabetes. One of the most commonly used enzymes in glucose biosensors is Glucose Oxidase (GOx). It is a biorecognition enzyme, which recognises the glucose molecule and acts as a catalyst to produce gluconic acid and hydrogen peroxide in the presence of glucose and oxygen. Ionic liquids (ILs) have evolved as a new type of solvent for biocatalysis, mainly due to their uniq...

  1. Thermodynamics of freezing and melting.

    Science.gov (United States)

    Pedersen, Ulf R; Costigliola, Lorenzo; Bailey, Nicholas P; Schrøder, Thomas B; Dyre, Jeppe C

    2016-01-01

    Although the freezing of liquids and melting of crystals are fundamental for many areas of the sciences, even simple properties like the temperature-pressure relation along the melting line cannot be predicted today. Here we present a theory in which properties of the coexisting crystal and liquid phases at a single thermodynamic state point provide the basis for calculating the pressure, density and entropy of fusion as functions of temperature along the melting line, as well as the variation along this line of the reduced crystalline vibrational mean-square displacement (the Lindemann ratio), and the liquid's diffusion constant and viscosity. The framework developed, which applies for the sizable class of systems characterized by hidden scale invariance, is validated by computer simulations of the standard 12-6 Lennard-Jones system. PMID:27530064

  2. Multifilament cellulose/chitin blend yarn spun from ionic liquids.

    Science.gov (United States)

    Mundsinger, Kai; Müller, Alexander; Beyer, Ronald; Hermanutz, Frank; Buchmeiser, Michael R

    2015-10-20

    Cellulose and chitin, both biopolymers, decompose before reaching their melting points. Therefore, processing these unmodified biopolymers into multifilament yarns is limited to solution chemistry. Especially the processing of chitin into fibers is rather limited to distinctive, often toxic or badly removable solvents often accompanied by chemical de-functionalization to chitosan (degree of acetylation, DA, fibers using ionic liquids (ILs) as gentle, removable, recyclable and non-deacetylating solvents. Chitin and cellulose are dissolved in ethylmethylimidazolium propionate ([C2mim](+)[OPr](-)) and the obtained one-pot spinning dope is used to produce multifilament fibers by a continuous wet-spinning process. Both the rheology of the corresponding spinning dopes and the structural and physical properties of the obtained fibers have been determined for different biopolymer ratios. With respect to medical or hygienic application, the cellulose/chitin blend fiber show enhanced water retention capacity compared to pure cellulose fibers. PMID:26256157

  3. Challenges in Melt Furnace Tests

    Science.gov (United States)

    Belt, Cynthia

    2014-09-01

    Measurement is a critical part of running a cast house. Key performance indicators such as energy intensity, production (or melt rate), downtime (or OEE), and melt loss must all be understood and monitored on a weekly or monthly basis. Continuous process variables such as bath temperature, flue temperature, and furnace pressure should be used to control the furnace systems along with storing the values in databases for later analysis. While using measurement to track furnace performance over time is important, there is also a time and place for short-term tests.

  4. Skull melting of synthetic minerals

    Energy Technology Data Exchange (ETDEWEB)

    Scott, S.D.; Hull, D.E.; Herrick, C.C.

    1977-12-01

    Direct high-frequency induction melting of dielectric materials in a water-cooled cage has been developed in the LASL synthetic minerals program. Molten material is contained in a skull, i.e., sintered shell, of its own composition so the traditional problems associated with refractory melt contamination are essentially eliminated. Preliminary analyses of power input, cage design, and coil geometry are discussed. Initial experimental results on the preparation of polycrystalline ingots, single crystals, and glasses are presented along with possible applications of this technique.

  5. Effect of Ions and Ionic Strength on Surface Plasmon Absorption of Single Gold Nanowires.

    Science.gov (United States)

    Baral, Susil; Green, Andrew J; Richardson, Hugh H

    2016-06-28

    The local temperature change from a single optically excited gold nanowire, lithographically prepared on Al0.94Ga0.06N embedded with Er(3+) ions, is measured in air, pure water, and various concentrations of aqueous solutions of ionic solutes of NaCl, Na2SO4, and MgSO4. The absorption cross section of the nanowire under pure water (2.25 × 10(-14) m(2)) and different solution ionic strength is measured from the slopes of temperature change versus laser intensity plots. Addition of charges into the solution decreases the amount of heat generated during optical excitation of the gold nanostructures because the absorption cross section of the gold nanowire is attenuated. A Langmuir-type behavior of the absorption cross section with ionic strength is observed that is identified with an increase in the occupancy of screened interfacial charges. The absorption cross section of the nanowire decreases with ionic strength until a saturation value of 9 × 10(-15) m(2), where saturation in the occupancy of screened interfacial charge occurs. Dynamic measurements of temperature for a single gold nanowire immersed in a microchannel flow cell show a sharp and fast temperature drop for the flow of ionic solution compared to the pure (deionized) water, suggesting that the technique can be developed as a sensor probe to detect the presence of ions in solution. PMID:27215955

  6. Solubilizing and Stabilizing Proteins in Anhydrous Ionic Liquids through Formation of Protein-Polymer Surfactant Nanoconstructs.

    Science.gov (United States)

    Brogan, Alex P S; Hallett, Jason P

    2016-04-01

    Nonaqueous biocatalysis is rapidly becoming a desirable tool for chemical and fuel synthesis in both the laboratory and industry. Similarly, ionic liquids are increasingly popular anhydrous reaction media for a number of industrial processes. Consequently, the use of enzymes in ionic liquids as efficient, environment-friendly, commercial biocatalysts is highly attractive. However, issues surrounding the poor solubility and low stability of enzymes in truly anhydrous media remain a significant challenge. Here, we demonstrate for the first time that engineering the surface of a protein to yield protein-polymer surfactant nanoconstructs allows for dissolution of dry protein into dry ionic liquids. Using myoglobin as a model protein, we show that this method can deliver protein molecules with near native structure into both hydrophilic and hydrophobic anhydrous ionic liquids. Remarkably, using temperature-dependent synchrotron radiation circular dichroism spectroscopy to measure half-denaturation temperatures, our results show that protein stability increases by 55 °C in the ionic liquid as compared to aqueous solution, pushing the solution thermal denaturation beyond the boiling point of water. Therefore, the work presented herein could provide a platform for the realization of biocatalysis at high temperatures or in anhydrous solvent systems. PMID:26976718

  7. CuO nanostructures: optical properties and morphology control by pyridinium-based ionic liquids.

    Science.gov (United States)

    Sabbaghan, Maryam; Shahvelayati, Ashraf Sadat; Madankar, Kamelia

    2015-01-25

    Copper oxide nanostructures have been synthesized by a simple reflux method in aqueous medium of pyridinium based ionic liquids. The structural and optical properties of CuO nanostructures were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence spectroscopy (PL) and UV-visible. The morphologies of the nanostructures can be controlled by changing the amount of NaOH and ionic liquids. The results show that the use identical pyridinium based ionic liquids in ratio of 4:1 NaOH/Cu(OAc)2⋅H2O yield minor differences in morphology of CuO nanostructures. Different morphologies of CuO nanostructures were obtained by changing the ratio NaOH/Cu(OAc)2⋅H2O to 2:1. Ionic liquids play an important role on optical properties of CuO nanostructures. The results of optical measurements of the CuO nanostructures illustrate that band gaps are estimated to be 1.67-1.85 eV. PL patterns studies show that the ionic liquids can be effect on PL patterns of the samples. The reasons of these phenomena are discussed.

  8. Ruthenium nanoparticles in ionic liquids: structural and stability effects of polar solutes.

    Science.gov (United States)

    Salas, Gorka; Podgoršek, Ajda; Campbell, Paul S; Santini, Catherine C; Pádua, Agílio A H; Costa Gomes, Margarida F; Philippot, Karine; Chaudret, Bruno; Turmine, Mireille

    2011-08-14

    Ionic liquids are a stabilizing medium for the in situ synthesis of ruthenium nanoparticles. Herein we show that the addition of molecular polar solutes to the ionic liquid, even in low concentrations, eliminates the role of the ionic liquid 3D structure in controlling the size of ruthenium nanoparticles, and can induce their aggregation. We have performed the synthesis of ruthenium nanoparticles by decomposition of [Ru(COD)(COT)] in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [C(1)C(4)Im][NTf(2)], under H(2) in the presence of varying amounts of water or 1-octylamine. For water added during the synthesis of metallic nanoparticles, a decrease of the solubility in the ionic liquid was observed, showed by nanoparticles located at the interface between aqueous and ionic phases. When 1-octylamine is present during the synthesis, stable nanoparticles of a constant size are obtained. When 1-octylamine is added after the synthesis, aggregation of the ruthenium nanoparticles is observed. In order to explain these phenomena, we have explored the molecular interactions between the different species using (13)C-NMR and DOSY (Diffusional Order Spectroscopy) experiments, mixing calorimetry, surface tension measurements and molecular simulations. We conclude that the behaviour of the ruthenium nanoparticles in [C(1)C(4)Im][NTf(2)] in the presence of 1-octylamine depends on the interaction between the ligand and the nanoparticles in terms of the energetics but also of the structural arrangement of the amine at the nanoparticle's surface. PMID:21603700

  9. Microwave-Assisted Method for Simultaneous Extraction and Hydrolysis for Determination of Flavonol Glycosides in Ginkgo Foliage Using Brönsted Acidic Ionic-Liquid [HO3S(CH24mim]HSO4 Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Yuangang Zu

    2012-07-01

    Full Text Available The Brönsted acidic ionic-liquid [HO3S(CH24mim] HSO4, a novel dual catalyst–solvent, has been successfully applied in simultaneous microwave-assisted extraction and hydrolysis for the determination of flavonol glycosides in Ginkgo foliage. The parameters, namely the [HO3S(CH24mim]HSO4 concentration, microwave-irradiation power, microwave-irradiation time, and solid–liquid ratio, were optimized. The optimum conditions were: an amount of 1.5 M [HO3S(CH24mim]HSO4, a microwave-irradiation power of 120 W, an irradiation time of 15 min, and a solid–liquid ratio of 1:30 g/mL. Compared with traditional methods the proposed approach demonstrates higher efficiency in a shorter operating time, and is an efficient, rapid, and simple sample preparation method.

  10. Thermodynamic characteristics of acid-base equilibria of DL-α-alanyl-DL-norleucine in aqueous solutions at 298 K

    Science.gov (United States)

    Lytkin, A. I.; Chernikov, V. V.; Krutova, O. N.; Bychkova, S. A.; Skvortsov, I. A.

    2015-09-01

    Protolytic equilibria in aqueous solutions of DL-α-alanyl-DL-norleucine are studied via potentiometry and calorimetry. Measurements are made at 298.15 K and ionic strengths of 0.5, 1.0, and 1.5 (against a background of potassium nitrate). The thermodynamic characteristics (p K, Δ G, Δ H, Δ S) of the stepwise dissociation of the dipeptide both in aqueous-salt solutions and in standard solution are obtained for the first time.

  11. Quantized Friction across Ionic Liquid Thin Films

    OpenAIRE

    Smith, Alexander M.; Lovelock, Kevin R. J.; Gosvami, Nitya Nand; Welton, Tom; Perkin, Susan

    2013-01-01

    Ionic liquids, salts in the liquid state under ambient conditions, are of great interest as precision lubricants. Ionic liquids form layered structures at surfaces, yet it is not clear how this nano-structure relates to their lubrication properties. We measured the friction force between atomically smooth solid surfaces across ionic liquid films of controlled thickness in terms of the number of ion layers. Multiple friction-load regimes emerge, each corresponding to a different number of ion ...

  12. Adsorption of CTAB onto perlite samples from aqueous solutions.

    Science.gov (United States)

    Alkan, Mahir; Karadaş, Mecit; Doğan, Mehmet; Demirbaş, Ozkan

    2005-11-15

    In this study, the adsorption properties of unexpanded and expanded perlite samples in aqueous cetyltrimethylammonium bromide (CTAB) solutions were investigated as a function of ionic strength, pH, and temperature. It was found that the amount of cetyltrimethylammonium bromide adsorbed onto unexpanded perlite was greater than that onto expanded perlite. For both perlite samples, the sorption capacity increased with increasing ionic strength and pH and decreasing temperature. Experimental data were analyzed by Langmuir and Freundlich isotherms and it was found that the experimental data were correlated reasonably well by the Freundlich adsorption isotherm. Furthermore, the isotherm parameters (KF and n) were also calculated. The adsorption enthalpy was determined from experimental data at different temperatures. Results have shown that the interaction between the perlite surface and CTAB is a physical interaction, and the adsorption process is an exothermic one.

  13. An anion effect on the separation of AgI-containing melts using sound waves

    International Nuclear Information System (INIS)

    Highlights: • The sound velocity in the (AgI + LiBr) and (AgI + LiF) melts was measured as a function of the temperature. • The system (AgI + LiBr) is biphasic between the melting point and 984 K. • The sound velocities for the coexisting phases converge when the temperature increases. • The (LiF + AgI) melt remains biphasic at all temperatures investigated up to 1218 K. - Abstract: Sound velocities in molten ((LiF + AgI)) and ((LiBr + AgI)) mixtures have been measured to investigate the relationship between the sound velocity and the temperature and the role of the anion in the (liquid + liquid) phase transition. Our results show that the ((LiBr + AgI)) system is biphasic between the melting point and T = 984 K and becomes monophasic above this temperature. We show that the upper consolute critical temperature for the AgI-containing melts increases with decreasing anion size in the series F− > Cl− > Br−. The ((LiF + AgI)) melt remains biphasic at all temperatures investigated up to T = 1218 K. The temperature coefficients for the sound velocities in the upper and lower phases of the ((LiBr + AgI)) system have opposite signs because of the superposition of the temperature and composition factors. The difference between the magnitudes of the velocities for the coexisting phases decreases exponentially with increasing temperature and is described by a critical exponent of 0.85 for the ((LiBr + AgI)) melt near the critical temperature. This value is 15% less than that found for alkali halide melts, in which long-range Coulomb forces between ions prevail. This difference may result from the fact that silver halides are intermediate between the typical ionic salts and the fully covalently bonded ones

  14. Supported Ionic Liquid Phase (SILP) catalysis

    DEFF Research Database (Denmark)

    Riisager, Anders; Fehrmann, Rasmus; Haumann, Marco;

    2006-01-01

    Applications of ionic liquids to replace conventional solvents in homogeneous transition-metal catalysis have increased significantly during the last decade. Biphasic ionic liquid/organic liquid systems offer advantages with regard to product separation, catalyst stability, and recycling...... but utilise in the case of fast chemical reactions only a small amount of expensive ionic liquid and catalyst. The novel Supported Ionic Liquid Phase (SILP) catalysis concept overcomes these drawbacks and allows the use of fixed-bed reactors for continuous reactions. In this Microreview the SILP catalysis...

  15. Improved Ionic Liquids as Space Lubricants Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Ionic liquids are candidate lubricant materials. However for application in low temperature space mechanisms their lubrication performance needs to be enhanced. UES...

  16. Corrosion problems with aqueous coolants, final report

    Energy Technology Data Exchange (ETDEWEB)

    Diegle, R B; Beavers, J A; Clifford, J E

    1980-04-11

    The results of a one year program to characterize corrosion of solar collector alloys in aqueous heat-transfer media are summarized. The program involved a literature review and a laboratory investigation of corrosion in uninhibited solutions. It consisted of three separate tasks, as follows: review of the state-of-the-art of solar collector corrosion processes; study of corrosion in multimetallic systems; and determination of interaction between different waters and chemical antifreeze additives. Task 1 involved a comprehensive review of published literature concerning corrosion under solar collector operating conditions. The reivew also incorporated data from related technologies, specifically, from research performed on automotive cooling systems, cooling towers, and heat exchangers. Task 2 consisted of determining the corrosion behavior of candidate alloys of construction for solar collectors in different types of aqueous coolants containing various concentrations of corrosive ionic species. Task 3 involved measuring the degradation rates of glycol-based heat-transfer media, and also evaluating the effects of degradation on the corrosion behavior of metallic collector materials.

  17. Adsorption of ionic liquid onto halloysite nanotubes: Thermal and mechanical properties of heterophasic PE-PP copolymer nanocomposites

    Science.gov (United States)

    Bischoff, E.; Simon, D. A.; Liberman, S. A.; Mauler, R. S.

    2016-03-01

    The surface adsorption of inorganic clays with ionic liquids has attracted much attention due to improve the interaction of hydrophilic clay with the hydrophobic polymers. However, successful organic adsorption strongly depends on the characteristics of ionic liquid (anion, chain size and concentration), and the reaction conditions (as polarity of solvent). In this study, such factors were analyzed and correlated with morphology, thermal and mechanical properties of the nanocomposites. The heterophasic ethylene-propylene copolymer nanocomposites were prepared by melt intercalation method in a twin screw co-rotating extruder. The halloysite nanotubes (HNT) was used as filler - natural and modified with different ionic liquids. The results showed that a better distribution and dispersion of the nanoparticles was achieved in the samples with modified HNT (m-HNT) and was more significant when the ionic liquid adsorption was conducted in a less polar solvent. The thermal stability of the nanocomposites with m- HNT was higher compared to the neat CP. Additionally, the better balance in the mechanical properties was obtained by the use of the more hydrophobic ionic liquid and higher concentration with improve of 27% in the Young Modulus without loss in the impact properties at room temperature. These superior behaviors of ionic liquid adsorption products exhibit properties suitable for many industrial applications.

  18. The Importance of the Ionic Product for Water to Understand the Physiology of the Acid-Base Balance in Humans

    OpenAIRE

    Adeva-Andany, María M.; Natalia Carneiro-Freire; Cristóbal Donapetry-García; Eva Rañal-Muíño; Yosua López-Pereiro

    2014-01-01

    Human plasma is an aqueous solution that has to abide by chemical rules such as the principle of electrical neutrality and the constancy of the ionic product for water. These rules define the acid-base balance in the human body. According to the electroneutrality principle, plasma has to be electrically neutral and the sum of its cations equals the sum of its anions. In addition, the ionic product for water has to be constant. Therefore, the plasma concentration of hydrogen ions depends on th...

  19. Ionic versus nonionic contrast use.

    Science.gov (United States)

    Stolberg, H O; McClennan, B L

    1991-01-01

    It has taken many years of research, development and intense scientific investigation to produce intravascular contrast media. Research on relations between chemical structure, animal toxicity, and water-solubility has produced a number of highly water-soluble, iodinated compounds for use in diagnostic radiology as intravascular contrast agents. The currently used intravascular agents may be classified into four groups according to their chemical structure: 1. Ionic monomers 2. Ionic monoacid dimers 3. Nonionic monomers 4. Nonionic dimers It is the objective of this publication to review the history and development of intravascular contrast media as well as their properties, general effects and clinical use. The four types of contrast media differ significantly in their chemical structure and physico-chemical properties, and these differences determine their osmotoxicity, chemotoxicity, and ion toxicity. We analyze the organ specific toxic effects of intravascular contrast media upon the central nervous system, the cardiovascular system, and the renal system. We also review the secondary effects, clinical manifestations, and the incidence of adverse events associated with different types of contrast. The choice of contrast media has become critical since the introduction of nonionic agents because their toxicological and pharmacological properties differ from those of the ionic agents. The application of basic concepts involved in the use of contrast media in excretory urography, computed tomography, angiography, and angiocardiography is discussed, and the advantages of the use of nonionic contrast agents are outlined. Economic and ethical issues are presented with emphasis upon strategies to reduce the risk associated with the injection of intravascular contrast and to curtail consumption according to rational principles of use. PMID:2049958

  20. Ionic self-assembly affords mesoporous ionic networks by crosslinking linear polyviologens with polyoxometalate clusters.

    Science.gov (United States)

    Chen, Guojian; Hou, Wei; Li, Jing; Wang, Xiaochen; Zhou, Yu; Wang, Jun

    2016-03-21

    Ionic-bonded mesoporous ionic networks were prepared by the ionic self-assembly of polyoxometalate (POM) clusters with linear cationic polyviologens in water. The POM-enriched PMIN-2(V) possesses a high surface area up to 120 m(2) g(-1), exhibiting superior non-noble metal heterogeneous catalytic performance in the ambient aerobic selective oxidation of 5-hydroxymethylfurfural. PMID:26898883

  1. Electrochemical deposition of coating from carbide, boride and silicide of IV-VIA group metals in ion melts

    International Nuclear Information System (INIS)

    The prehistory of the development of methods of production of metal-like refractory coatings (titanium, tantalum, niobium, vanadium, zirconium carbides, borides and silicides) with the help of high-temperature electrochemical synthesis (HTES) in ionic melts is described. A review is made on studies into the process of HTES of refractory metal borides, carbides and silicides, manufacture conditions for the coatings and electrolyte compositions (oxide, oxide-fluoride, chloride, chloride-fluoride melts). Structure and properties of coatings produced by the method of HTES are under consideration

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

    Science.gov (United States)

    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. PMID:26785819

  3. First title: Ionic liquids-useful reaction green solvents for the future Second title: ionic liquids are the replacements for environmentally damaging solvents in a wide range of chemical processes.

    OpenAIRE

    K.Vijaya Bhaskar

    2012-01-01

    Ionic liquids (IL) represent fascinating new class of solvents with unusual physical and chemical properties; low melting salts (up to 1000C). The main driving force for research in this area is the need to find replacement for environmentally damaging solvents in a wide range of chemical processes. To date, most chemical reactions have been carried out in molecular solvents. For the past twenty years, most of our understanding of our chemistry has been based upon the behavior of molecules in...

  4. The Influence of Silica Nanoparticles on Ionic Liquid Behavior: A Clear Difference between Adsorption and Confinement

    Directory of Open Access Journals (Sweden)

    Guozhong Wu

    2013-10-01

    Full Text Available The phase behaviors of ionic liquids (ILs confined in nanospace and adsorbed on outer surface of nanoparticles are expected to be different from those of the bulk. Anomalous phase behaviors of room temperature ionic liquid tributylhexadecylphosphonium bromide (P44416Br confined in ordered mesoporous silica nanoparticles with average pore size 3.7 nm and adsorbed on outer surface of the same silica nanoparticles were reported. It was revealed that the melting points (Tm of confined and adsorbed ILs depressed significantly in comparison with the bulk one. The Tm depressions for confined and adsorbed ILs are 8 °C and 14 °C, respectively. For comparison with the phase behavior of confined P44416Br, 1-butyl-3-methylimidazolium bromide (BmimBr was entrapped within silica nanopores, we observed an enhancement of 50 °C in Tm under otherwise similar conditions. The XRD analysis indicates the formation of crystalline-like phase under confinement, in contrast to the amorphous phase in adsorbed IL. It was confirmed that the behavior of IL has clear difference. Moreover, the complex π-π stacking and H-bonding do not exist in the newly proposed phosphonium-based IL in comparison with the widely studied imidazolium-based IL. The opposite change in melting point of P44416Br@SiO2 and BmimBr@SiO2 indicates that the cationic species plays an important role in the variation of melting point.

  5. Ionic liquids for nano- and microstructures preparation. Part 2: Application in synthesis.

    Science.gov (United States)

    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

  6. Characterization of aqueous silver nitrate solutions for leakage tests

    OpenAIRE

    José Ferreira Costa; Walter Luiz Siqueira; Alessandro Dourado Loguercio; Alessandra Reis; Elizabeth de Oliveira; Cláudia Maria Coelho Alves; José Roberto de Oliveira Bauer; Rosa Helena Miranda Grande

    2011-01-01

    OBJECTIVE: To determine the pH over a period of 168 h and the ionic silver content in various concentrations and post-preparation times of aqueous silver nitrate solutions. Also, the possible effects of these factors on microleakage test in adhesive/resin restorations in primary and permanent teeth were evaluated. MATERIAL AND METHODS: A digital pHmeter was used for measuring the pH of the solutions prepared with three types of water (purified, deionized or distilled) and three brands of silv...

  7. Ionic Interactions in Actinide Tetrahalides

    Science.gov (United States)

    Akdeniz, Z.; Karaman, A.; Tosi, M. P.

    2001-05-01

    We determine a model of the ionic interactions in AX 4 compounds (where A is an atom in the actinide series from Th to Am and X = F, Cl, Br or I) by an analysis of data on the static and dynamic structure of their molecular monomers. The potential energy function that we adopt is taken from earlier work on rare-earth trihalides [Z. Akdeniz, Z. Q q e k and M. P. Tosi, Z. Naturforsch. 55a, 861 (2000)] and in particular allows for the electronic polarizability of the actinide ion. This polarizability quantitatively determines the antisymmetric-bending vibrational mode, but its magnitude remains compatible with a symmetric tetrahedral shape of the molecule at equilibrium. The fluorides have an especially high degree of ionic character, and the interionic-force parameters for each halide of the U, Np, Pu and Am series show regular trends, suggesting that extrapolations to the other transuranic-element halides may usefully be made. The Th compounds show some deviations from these trends, and the interionic-force model that we determine for ThCl4 differs somewhat from that obtained in a previous study. We therefore return on the evaluation of the relative stability of charged oligomers of ThCl4 and ZrCl4 and find confirmation of our earlier results on this problem.

  8. Asymmetric Melting and Freezing Kinetics in Silicon.

    OpenAIRE

    Aziz, Michael; Tsao, Jeff Y.; Thompson, Michael O.; Peercy, Paul S.

    1986-01-01

    We report measurements of the melting velocity of amorphous Si relative to that of (100) crystalline Si. These measurements permit the first severe experimental test of theories describing highly nonequilibrium freezing and melting. The results indicate that freezing in Si is inherently slower than melting; this asymmetry can be interpreted in terms of an entropy-related reduction in the freezing rate.

  9. Filament stretching rheometry of polymer melts

    DEFF Research Database (Denmark)

    Hassager, Ole; Nielsen, Jens Kromann; Rasmussen, Henrik Koblitz

    2005-01-01

    The Filament Stretching Rheometry (FSR) method developed by Sridhar, McKinley and coworkers for polymer solutions has been extended to be used also for polymer melts. The design of a melt-FSR will be described and differences to conventional melt elongational rheometers will be pointed out. Results...

  10. Ionic melts with waterlike anomalies: thermodynamic properties of liquid BeF2.

    Science.gov (United States)

    Agarwal, Manish; Sharma, Ruchi; Chakravarty, Charusita

    2007-10-28

    Thermodynamic properties of liquid beryllium difluoride (BeF(2)) are studied using canonical ensemble molecular dynamics simulations of the transferable rigid ion model potential. The negative slope of the locus of points of maximum density in the temperature-pressure plane is mapped out. The excess entropy, computed within the pair correlation approximation, is found to show an anomalous increase with isothermal compression at low temperatures which will lead to diffusional as well as structural anomalies resembling those in water. The anomalous behavior of the entropy is largely connected with the behavior of the Be-F pair correlation function. The internal energy shows a T(35) temperature dependence. The pair correlation entropy shows a T(-25) temperature dependence only at high densities and temperatures. The correlation plots between internal energy and the pair correlation entropy for isothermal compression show the characteristic features expected of network-forming liquids with waterlike anomalies. The tagged particle potential energy distributions are shown to have a multimodal form at low temperatures and densities similar to those seen in other liquids with three-dimensional tetrahedral networks, such as water and silica. PMID:17979355

  11. Homogeneous liquid-liquid extraction of rare earths with the betaine-betainium bis(trifluoromethylsulfonyl)imide ionic liquid system.

    Science.gov (United States)

    Vander Hoogerstraete, Tom; Onghena, Bieke; Binnemans, Koen

    2013-01-01

    Several fundamental extraction parameters such as the kinetics and loading were studied for a new type of metal solvent extraction system with ionic liquids. The binary mixture of the ionic liquid betainium bis(trifluoromethylsulfonyl)imide and water shows thermomorphic behavior with an upper critical solution temperature (UCST), which can be used to avoid the slower mass transfer due to the generally higher viscosity of ionic liquids. A less viscous homogeneous phase and mixing on a molecular scale are obtained when the mixture is heated up above 55 °C. The influence of the temperature, the heating and cooling times, were studied for the extraction of neodymium(III) with betaine. A plausible and equal extraction mechanism is proposed in bis(trifluoromethylsulfonyl)imide, nitrate, and chloride media. After stripping of the metals from the ionic liquid phase, a higher recovery of the ionic liquid was obtained by salting-out of the ionic liquid fraction lost by dissolution in the aqueous phase. The change of the upper critical solution temperature by the addition of HCl or betaine was investigated. In addition, the viscosity was measured below and above the UCST as a function of the temperature. PMID:24169434

  12. Intermolecular/interionic vibrations of 1-methyl-3-n-octylimidazolium tetrafluoroborate ionic liquid and H2O mixtures.

    Science.gov (United States)

    Shirota, Hideaki; Biswas, Ranjit

    2012-11-26

    We report here the low-frequency spectra, resulting from the intermolecular/interionic vibrational dynamics, of aqueous mixtures of an ionic liquid, 1-methyl-3-n-octylimidazolium tetrafluoroborate, with the H(2)O mole fractions of 0.2, 0.4, and 0.6 and the neat ionic liquid and H(2)O within the frequency range of 0.1-700 cm(-1) by means of femtosecond Raman-induced Kerr effect spectroscopy. Addition of H(2)O induces tiny effects on the line shape of the low-frequency Kerr spectrum of the ionic liquid: ca. a 2 cm(-1) red shift in the first moment of the low-frequency spectrum has been observed for a transition from the neat ionic liquid to the binary mixture containing 0.6 mol fraction of H(2)O. Surface tension and liquid density of the mixture also accompany minimal changes upon addition of H(2)O. These results suggest that H(2)O molecules localize at the interface between the ionic and nonpolar regions, and the interionic interaction in the ionic region is weakly perturbed by the existence of H(2)O. On the other hand, successive addition of H(2)O in the mixture slows down the picosecond overdamped relaxation process measured in the 3-300 ps range even though the shear viscosity of the mixture decreases substantially. PMID:23148797

  13. Hadron melting and QCD thermodynamics

    OpenAIRE

    Jakovac, A.

    2013-01-01

    We study in this paper mechanisms of hadron melting based on the spectral representation of hadronic quantum channels, and examine the hadron width dependence of the pressure. The findings are applied to a statistical hadron model of QCD thermodynamics, where hadron masses are distributed by the Hagedorn model and a uniform mechanism for producing hadron widths is assumed. According to this model the hadron - quark gluon plasma transition occurs at $T\\approx 200$-250 MeV, the numerically obse...

  14. Branched isomeric 1,2,3-triazolium-based ionic liquids: new insight into structure-property relationships.

    Science.gov (United States)

    Lartey, M; Meyer-Ilse, J; Watkins, J D; Roth, E A; Bowser, S; Kusuma, V A; Damodaran, K; Zhou, X; Haranczyk, M; Albenze, E; Luebke, D R; Hopkinson, D; Kortright, J B; Nulwala, H B

    2015-11-28

    A series of four isomeric 1,2,3-triazolium-based ionic liquids (ILs) with vary degree of branching were synthesized and characterized to investigate the effect of ion branching on thermal and physical properties of the resulting IL. It was found that increased branching led to a higher ionicity and higher viscosity. The thermal properties were also altered significantly and spectral changes in the near edge X-ray absorption fine structure (NEXAFS) spectra show that branching affects intermolecular interaction. While the ionicity and viscosity varying linearly with branching, the MDSC and NEXAFS measurements show that the cation shape has a stronger influence on the melting temperature and absorptive properties than the number of branched alkyl substituents. PMID:26486091

  15. Gaseous Hydrocarbon Separations Using Functionalized Ionic Liquids

    Directory of Open Access Journals (Sweden)

    Moura Leila

    2016-03-01

    Full Text Available The functionalization of the side chains on the cation or the anion of an ionic liquid is a common approach to tailor its properties for different processes including the separation of gases. In this paper, we present the current state of the art concerning the usage of ionic liquids for hydrocarbon separations. We also show how the functionalization of ionic liquids or the appropriate anion/cation combinations can contribute to the increase of the performance of the ionic liquids for the separation of gaseous hydrocarbons – either by improving the capacity of the ionic liquid to absorb a given gas or by increasing the selectivity towards a particular hydrocarbon. Original results concerning the usage of olefin-complexing metal salts of lithium (I, nickel (II and copper (II dissolved in ionic liquids for selectively absorbing light olefins are presented. It is observed that the absorption capacity of an imidazolium-based ionic liquid is doubled by the addition of a copper (II salt. This result is compared with the effect of the functionalization of the ionic liquid and the advantages and difficulties of the two approaches are analyzed.

  16. Ionic liquid-in-oil microemulsions.

    Science.gov (United States)

    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. PMID:15898765

  17. Improved ionic model of liquid uranium dioxide

    NARCIS (Netherlands)

    Gryaznov, [No Value; Iosilevski, [No Value; Yakub, E; Fortov, [No Value; Hyland, GJ; Ronchi, C

    2000-01-01

    The paper presents a model for liquid uranium dioxide, obtained by improving a simplified ionic model, previously adopted to describe the equation of state of this substance [1]. A "chemical picture" is used for liquid UO2 of stoichiometric and non-stoichiometric composition. Several ionic species a

  18. Engineered microorganisms having resistance to ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Ruegg, Thomas Lawrence; Thelen, Michael P.

    2016-03-22

    The present invention provides for a method of genetically modifying microorganisms to enhance resistance to ionic liquids, host cells genetically modified in accordance with the methods, and methods of using the host cells in a reaction comprising biomass that has been pretreated with ionic liquids.

  19. Aqueous polyethylene oxide solutions

    International Nuclear Information System (INIS)

    A number of aspects concerning the reorientation of polymer, water and ion hydration complexes have been studied in aqueous solution of polyethylene oxide (PEO). The polymer dynamics are investigated by 1H-PEO and 13C-PEO nuclear relaxation experiments. 162 refs.; 30 figs.; 19 tabs

  20. Treatment of Aqueous Solutions

    NARCIS (Netherlands)

    Van Spronsen, J.; Witkamp, G.J.

    2013-01-01

    The invention is directed to a process for the recovery or removal of one or more crystallizable compounds from an aqueous solution containing, apart from the said crystallizable compounds, one or more organic or inorganic scale- forming or scale-inducing materials having a lower solubility in water

  1. Melting and Sintering of Ashes

    DEFF Research Database (Denmark)

    Hansen, Lone Aslaug

    1997-01-01

    in the ashes lead to increased melt fractions in the temperature range 600-750°C.b) Bottom ashes from straw combustion consist purely of silicates, with varying ratios of the quite refractory Al-silicates and quartz to the less refractory K- and Ca-silicates. Bottom ashes melt in the temperature range 800......-1300°C, and a trend of higher fusion temperatures with increasing contents of Al-silicates and quartz was found.c) Fly ashes, bottom ashes and deposits from coal/straw co-firing were all found to consist mainly of metal-alumina and alumina-silicates. These ashes all melt in the temperature range 1000......The thesis contains an experimental study of the fusion and sintering of ashes collected during straw and coal/straw co-firing.A laboratory technique for quantitative determination of ash fusion has been developed based on Simultaneous Thermal Analysis (STA). By means of this method the fraction...

  2. A Diazonium Salt-Based Ionic Liquid for Solvent-FreeModification of Carbon.

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Chengdu [ORNL; Huang, Jing-Fang [ORNL; Li, Zuojiang [ORNL; Luo, Huimin [ORNL; Dai, Sheng [ORNL

    2006-01-01

    A novel ionic liquid that consists of p-butylbenzenediazonium ions and bis(trifluoromethanesulfonyl)amidates (Tf{sub 2}N{sup -}) has been synthesized as a task-specific ionic liquid for the solvent-free modification of carbon materials. The use of anions Tf{sub 2}N{sup =} is the key to rendering the hydrophobicity, low liquidus temperature, and ionicity to this novel molten salt. This diazonium salt has a melting point of 7.2 C and a moderate electric conductivity of 527 {micro} s/cm at 25 C. The thermal stability of this diazonium ionic liquid has been investigated by high-resolution thermogravimetric analysis (HRTGA). The compound is stable up to about 90 C in nitrogen, which is only 10 C less than its solid tetrafluoroborate counterpart. The modification of carbon materials has been carried out through both thermal and electrochemical activations of diazonium ions to generate free radical intermediates without the use of any solvent. The surface-coverage loadings of 3.38 {micro} mol/m{sup 2} and 6.07 {micro} mol/m{sup 2} for covalently attached organic functionalities have been achieved by the thermally induced functionalization and electrochemically assisted reaction, respectively.

  3. Synthesis and properties of alkoxy- and alkenyl-substituted peralkylated imidazolium ionic liquids.

    Science.gov (United States)

    Maton, Cedric; Brooks, Neil R; Van Meervelt, Luc; Binnemans, Koen; Schaltin, Stijn; Fransaer, Jan; Stevens, Christian V

    2013-10-21

    Novel peralkylated imidazolium ionic liquids bearing alkoxy and/or alkenyl side chains have been synthesized and studied. Different synthetic routes towards the imidazoles and the ionic liquids comprising bromide, iodide, methanesulfonate, bis(trifluoromethylsulfonyl)imide ([NTf2](-)), and dicyanamide {[N(CN)2](-)} as the anion were evaluated, and this led to a library of analogues, for which the melting points, viscosities, and electrochemical windows were determined. Incorporation of alkenyl moieties hindered solidification, except for cations with high symmetry. The alkoxy-derivatized ionic liquids are often crystalline; however, room-temperature ionic liquids (RTILs) were obtained with the weakly coordinating anions [NTf2](-) and [N(CN)2](-). For the viscosities of the peralkylated RTILs, an opposite trend was found, that is, the alkoxy derivatives are less viscous than their alkenyl-substituted analogues. Of the crystalline compounds, X-ray diffraction data were recorded and related to their molecular properties. Upon alkoxy substitution, the electrochemical cathodic limit potential was found to be more positive, whereas the complete electrochemical window of the alkenyl-substituted imidazolium salts was shifted to somewhat more positive potentials.

  4. Low Temperature Reduction of Alumina Using Fluorine Containing Ionic Liquids

    Energy Technology Data Exchange (ETDEWEB)

    Dr. R. G. Reddy

    2007-09-01

    The major objective of the project is to establish the feasibility of using specific ionic liquids capable of sustaining aluminum electrolysis near room temperature at laboratory and batch recirculation scales. It will explore new technologies for aluminum and other valuable metal extraction and process methods. The new technology will overcome many of the limitations associated with high temperatures processes such as high energy consumption and corrosion attack. Furthermore, ionic liquids are non-toxic and could be recycled after purification, thus minimizing extraction reagent losses and environmental pollutant emissions. Ionic liquids are mixture of inorganic and organic salts which are liquid at room temperature and have wide operational temperature range. During the last several years, they were emerging as novel electrolytes for extracting and refining of aluminum metals and/or alloys, which are otherwise impossible using aqueous media. The superior high temperature characteristics and high solvating capabilities of ionic liquids provide a unique solution to high temperature organic solvent problems associated with device internal pressure build-up, corrosion, and thermal stability. However their applications have not yet been fully implemented due to the insufficient understanding of the electrochemical mechanisms involved in processing of aluminum with ionic liquids. Laboratory aluminum electrodeposition in ionic liquids has been investigated in chloride and bis (trifluoromethylsulfonyl) imide based ionic liquids. The electrowinning process yielded current density in the range of 200-500 A/m2, and current efficiency of about 90%. The results indicated that high purity aluminum (>99.99%) can be obtained as cathodic deposits. Cyclic voltammetry and chronoamperometry studies have shown that initial stages of aluminum electrodeposition in ionic liquid electrolyte at 30°C was found to be quasi-reversible, with the charge transfer coefficient (0.40). Nucleation

  5. Improvement in Aqueous Solubility of Retinoic Acid Receptor (RAR) Agonists by Bending the Molecular Structure.

    Science.gov (United States)

    Hiramatsu, Michiaki; Ichikawa, Yuki; Tomoshige, Shusuke; Makishima, Makoto; Muranaka, Atsuya; Uchiyama, Masanobu; Yamaguchi, Takao; Hashimoto, Yuichi; Ishikawa, Minoru

    2016-08-01

    Aqueous solubility is a key requirement for many functional molecules, e. g., drug candidates. Decrease of the partition coefficient (log P) by chemical modification, i.e., introduction of hydrophilic group(s) into molecules, is a classical strategy for improving aqueous solubility. We have been investigating alternative strategies for improving the aqueous solubility of pharmaceutical compounds by disrupting intermolecular interactions. Here, we show that introducing a bend into the molecular structure of retinoic acid receptor (RAR) agonists by changing the substitution pattern from para to meta or ortho dramatically enhances aqueous solubility by up to 890-fold. We found that meta analogs exhibit similar hydrophobicity to the parent para compound, and have lower melting points, supporting the idea that the increase of aqueous solubility was due to decreased intermolecular interactions in the solid state as a result of the structural changes. PMID:27378357

  6. Ionic liquid incorporating thiosalicylate for metal removal

    Science.gov (United States)

    Wilfred, Cecilia Devi; Mustafa, Fadwa Babiker; Romeli, Fatimah Julia

    2012-09-01

    Ionic liquids are a class of organic molten salts "designer solvents" that are composed totally of anions (inorganic and organic polyatomic) and organic cations. The replacement of volatile organic solvents from a separation process is of utmost importance since the use of a large excess of these solvents is hazardous and creates ecological problem. The new method for metal ion extraction is by using task-specific ionic liquids such as ionic liquids which incorporate thiosalicylate functionality. This paper looks at producing a new cluster of ionic liquids which incorporates thiosalicylate with pyridinium cation. Its thermophysical properties such as density and viscosity in single and binary mixtures are studied. The ionic liquids' capability in metal removal processes is evaluated.

  7. Application of Ionic Liquids in Hydrometallurgy

    Directory of Open Access Journals (Sweden)

    Jesik Park

    2014-08-01

    Full Text Available Ionic liquids, low temperature molten salts, have various advantages manifesting themselves as durable and environmentally friendly solvents. Their application is expanding into various fields including hydrometallurgy due to their unique properties such as non-volatility, inflammability, low toxicity, good ionic conductivity, and wide electrochemical potential window. This paper reviews previous literatures and our recent results adopting ionic liquids in extraction, synthesis and processing of metals with an emphasis on the electrolysis of active/light, rare earth, and platinum group metals. Because the research and development of ionic liquids in this area are still emerging, various, more fundamental approaches are expected to popularize ionic liquids in the metal manufacturing industry.

  8. Standard thermodynamic functions of complexation between copper(II) and glycine and L-histidine in aqueous solutions

    Science.gov (United States)

    Gorboletova, G. G.; Metlin, A. A.

    2016-09-01

    The Cu2+-glycine-L-histidine system is studied calorimetrically at 298.15 K and an ionic strength of 0.2, 0.5, and 1.0 in aqueous solutions containing potassium nitrate. The standard thermodynamic parameters (Δr H°, Δr G°, Δr S°) of complexation processes are determined.

  9. Effect of pH on the Electrophoretic Mobility of Spores of Bacillus anthracis and Its Surrogates in Aqueous Solutions

    Science.gov (United States)

    Electrophoretic mobility (EPM) of endospores of Bacillus anthracis and surrogates were measured in aqueous solution across a broad pH range and several ionic strengths. EPM values trended around phylogenetic clustering based on the 16S rRNA gene. Measurements reported here prov...

  10. Thermochemical study of the processes of complexation of cobalt(II) ions with L-histidine in aqueous solution

    Science.gov (United States)

    Gorboletova, G. G.; Metlin, A. A.

    2015-09-01

    Thermal effects of the complexation of cobalt(II) ions with L-histidine at 298.15 K and several values of the ionic strength against the background of KNO3 are determined by means of direct calorimetry. The standard thermodynamic characteristics of the reactions of complexation in the aqueous solution have been calculated.

  11. Determination and Correlation of Solubilities of Four Novel Benzothiazolium Ionic Liquids with 6PF- in Six Alcohols

    Institute of Scientific and Technical Information of China (English)

    何志坚; 王小敏; 姚田; 宋航; 姚舜

    2014-01-01

    Four novel benzothiazolium ionic liquids with 6PF- ([C1Bth][PF6], [C4Bth][PF6], [C5Bth][PF6] and [C6Bth][PF6]) were synthesized, and the rang of their melting points were determined between 358.35 K-424.05 K. The relationship of their melting points and the length of the straight alkyl chain on cation reflected‘S’ type ten-dency. Then, the solubilities of the four ionic liquids in six lower alcohols (methanol, ethanol, 1-propanol, 2-propanol, 1-butanol and 2-methyl-1-propanol) were measured in the temperature rang of 253.15-383.15 K at at-mospheric pressure with static analytical method, respectively. It was found that [C6Bth][PF6] in all investigated ionic liquids had the largest solubility in six alcohols and the solubility of [C4Bth][PF6] in methanol was very sensi-tive for temperature in 313.15-333.15 K, which was so-called “temperature-sensitivity”. This feature is of great significance to their application of catalyzing reaction or extraction process, and makes the recovery and reuse of ionic liquids (ILs) become easier. Moreover, the experimental solubility data were correlated with the modified Apelblat equation andλh equation, respectively. It was found that the result of correlation using two divided tem-perature ranges was better than that of using the whole temperature range.

  12. Antinociceptive activity of Delta9-tetrahydrocannabinol non-ionic microemulsions.

    Science.gov (United States)

    Lazzari, P; Fadda, P; Marchese, G; Casu, G L; Pani, L

    2010-06-30

    Delta(9)-Tetrahydrocannabinol (Delta(9)-THC), the major psychoactive constituent of Cannabis sativa L., has been widely studied for its potential pharmaceutical application in the treatment of various diseases and disturbs. This sparingly soluble terpeno-phenolic compound is not easy to handle and to be formulated in pharmaceutical preparations. The aim of this work was to develop a stable aqueous Delta(9)-THC formulation acceptable for different ways of administration, and to evaluate the therapeutic properties of the new Delta(9)-THC based preparation for pain treatment. Due to the thermodynamic stability and advantages of microemulsion based systems, the study was focused on the identification of aqueous microemulsion based systems containing Delta(9)-THC. Oil in water Delta(9)-THC microemulsions were individuated through phase diagrams construction, using the non-ionic surfactant Solutol HS15, being this surfactant acceptable for parenteral administration in human. A selected microemulsion samples containing 0.2 wt% of Delta(9)-THC, stable up to 52 degrees C, was successfully assayed on animal models of pain. Significant antinociceptive activity has been detected by both intraperitoneal and intragastric administration of the new Delta(9)-THC pharmaceutical preparation. The effect has been highlighted in shorter time if compared to a preparation of the same active principle based on previously reported conventional preparation. PMID:20399844

  13. Solid Catalyst with Ionic Liquid Layer (SCILL). A concept to improve the selectivity of selective hydrogenations

    Energy Technology Data Exchange (ETDEWEB)

    Jess, A.; Korth, W. [Bayreuth Univ. (Germany). Chair of Chemical Engineering

    2011-07-01

    Catalytic hydrogenations are important for refinery processes, petrochemical applications as well as for numerous processes of the fine chemicals industry. In some cases, hydrogenations consist of a sequence of consecutive reactions, and the desired product is the intermediate. An important goal is then a high yield and selectivity to the intermediate, if possible at a high conversion degree. The selectivity to an intermediate primarily depends on the chemical nature of the catalyst, but may also be influenced by diffusion processes. Ionic liquids (ILs) are low melting salts (< 100 C) and represent a promising solvent class. This paper focuses on the concept of a Solid Catalyst with Ionic Liquid Layer (SCILL), where the solid catalyst is coated with a thin IL layer to improve the selectivity. (orig.)

  14. Elastic properties of silicate melts at high pressure and implications for low velocity anomalies in the crust and mantle

    Science.gov (United States)

    Clark, A. N.; Lesher, C. E.

    2015-12-01

    Regions of low seismic velocities in the mantle and crust are commonly attributed to the presence of silicate melt or aqueous fluid. The elastic properties of silicate melts are typically modeled at high pressure using equations of state developed for crystalline materials. However, amorphous silicates spanning a wide range of composition and structure, i.e. SiO2 to MgSiO3, and including naturally occurring basalt compositions, exhibit a weak dependence of P-wave velocity on density in clear violation of Birch's law, which governs the behavior of crystalline materials. This anomalous behavior is attributed to the high degree of flexibility of the silicate network on loading that may be a general property of naturally occurring silicate melts at crustal and upper mantle conditions. If this is the case, P-wave velocities for silicate melts will be significantly less pressure dependent than previously assumed, which in turn will enhance the effects of melt fraction on lowering aggregate mantle seismic velocities. Here we present VP calculated for partially molten mantle up to 20 GPa showing that melt fractions purported to explain VP reductions associated with the lithosphere-asthenosphere boundary may be overestimated by 15%, while those reported for the transition zone may be overestimated to an even greater extent. Moreover, we predict that d lnVS/d lnVP (RSP) should vary little across low velocities regions within the upper mantle due solely to the presence of melt, but will be strongly influenced by how melt is distributed, consistent the work of [1]. Finally, RSP is found to be relatively insensitive to type of fluid present, contrary to conventional wisdom, and thus caution is warranted in attributing changes in RSP to either silicate melt or aqueous fluids. The implications of these findings for interpreting low velocity anomalies beneath hotspots and arcs (e.g. Iceland and Japan) will be discussed. [1] Takei, Y. (2002) JGR vol. 107

  15. The attenuation of oscillatory thermo-capillary convection in the oxide melt by a transverse magnetic field

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The effect of a transverse magnetic field on the oscillatory thermocapillary con- vection in the NaBi(WO4)2 melt was studied by using the in-situ observation system. The oscillation was attenuated when the 60 mT magnetic field was applied, as shown by the decrease in the amplitude and the frequency. Furthermore, the os- cillation under smaller temperature difference was stabilized after the magnetic field was applied. The magnetic effect could be due to the Lorentz force generated by the interaction between motional ions and the vertical magnetic field. The ionic conductivities were measured to demonstrate the effect of the magnetic field. The solid ionic electrical conductivity increases with the temperature rise, and the melt ionic electrical conductivity was measured to be about 2.0×10-4 -1cm-1. Experi- mental results manifest that the effect of the magnetic field on anions and cations in the melt makes the flow change to the direction normal to the applied field, so the flow is more orderly and the oscillation is suppressed.

  16. Conductivity of Oxalic Acid in Aqueous Solution at Low Concentration%低浓度草酸水溶液的电导研究

    Institute of Scientific and Technical Information of China (English)

    倪良; 韩世钧

    2005-01-01

    Oxalic acid is a weak and unsymmetrical bi-basic acid. There exist dissociation and association equilibria among the species in aqueous solution. The molar conductivity of the solution is the sum of the ionic contributions.Based on this idea, a new prediction equation of ionic conductivity was proposed at low concentration. The molar conductivities of the solution and its relevant ions were calculated respectively. The results obtained were in good agreement with those from experiments and the Quint-Viallard equation.

  17. Microstructure and corrosion properties of diode laser melted friction stir weld of aluminum alloy 2024 T351

    Energy Technology Data Exchange (ETDEWEB)

    Kalita, Samar Jyoti, E-mail: Samar.Kalita@und.nodak.edu [Engineered Surfaces Center, School of Engineering and Mines, University of North Dakota, Grand Forks, ND (United States)

    2011-02-15

    Friction stir welding is a promising solid state joining process for high strength aluminum alloys. Though friction stir welding eliminates the problems of fusion welding as it is performed below melting temperature (T{sub m}), it creates severe plastic deformation. Friction stir welds of some aluminum alloys exhibit relatively poor corrosion resistance. This research enhanced the corrosion properties of such welds through diode laser surface melting. A friction stir weld of aluminum alloy 2024 T351 was laser melted using a 1 kW diode laser. The melt-depth and microstructure were investigated using optical and scanning electron microscopy. The melt zone exhibited epitaxially grown columnar grains. At the interface between the melted and the un-melted zone, a thick planar boundary was observed. Energy dispersive spectroscopy analyzed the redistribution of elemental composition. The corrosion properties of the laser melted and native welds were studied in aqueous 0.5 M sodium chloride solution using open circuit potential and cyclic potentiodynamic polarization. The results show noticeable increase in the pit nucleation resistance (390 mV) after the laser surface treatment. The repassivation potential was nobler to the corrosion potential after the laser treatment, which confirmed that the resistance to pit growth was improved.

  18. Infrared spectroscopy of ionic clusters

    International Nuclear Information System (INIS)

    This thesis describes new experiments wherein the infrared vibrational predissociation spectra of a number of mass-selected ionic cluster systems have been obtained and analyzed in the 2600 to 4000 cm-1 region. The species studied include: the hydrated hydronium ions, H3O+ (H2O)3-10, ammoniated ammonium ions, NH4+(NH3)1-10 and cluster ions involving both water and ammonia around an ammonium ion core, (mixed clusters) NH4+(NH3)n(H2O)m (n+m=4). In each case, the spectra reveal well resolved structures that can be assigned to transitions arising from the vibrational motions of both the ion core of the clusters and the surrounding neutral solvent molecules. 154 refs., 19 figs., 8 tabs

  19. Infrared spectroscopy of ionic clusters

    Energy Technology Data Exchange (ETDEWEB)

    Price, J.M. (California Univ., Berkeley, CA (USA). Dept. of Chemistry Lawrence Berkeley Lab., CA (USA))

    1990-11-01

    This thesis describes new experiments wherein the infrared vibrational predissociation spectra of a number of mass-selected ionic cluster systems have been obtained and analyzed in the 2600 to 4000 cm{sup {minus}1} region. The species studied include: the hydrated hydronium ions, H{sub 3}O{sup +} (H{sub 2}O){sub 3 {minus}10}, ammoniated ammonium ions, NH{sub 4}{sup +}(NH{sub 3}){sub 1 {minus}10} and cluster ions involving both water and ammonia around an ammonium ion core, (mixed clusters) NH{sub 4}{sup +}(NH{sub 3}){sub n}(H{sub 2}O){sub m} (n+m=4). In each case, the spectra reveal well resolved structures that can be assigned to transitions arising from the vibrational motions of both the ion core of the clusters and the surrounding neutral solvent molecules. 154 refs., 19 figs., 8 tabs.

  20. Actinide chemistry in ionic liquids.

    Science.gov (United States)

    Takao, Koichiro; Bell, Thomas James; Ikeda, Yasuhisa

    2013-04-01

    This Forum Article provides an overview of the reported studies on the actinide chemistry in ionic liquids (ILs) with a particular focus on several fundamental chemical aspects: (i) complex formation, (ii) electrochemistry, and (iii) extraction behavior. The majority of investigations have been dedicated to uranium, especially for the 6+ oxidation state (UO2(2+)), because the chemistry of uranium in ordinary solvents has been well investigated and uranium is the most abundant element in the actual nuclear fuel cycles. Other actinides such as thorium, neptunium, plutonium, americium, and curiumm, although less studied, are also of importance in fully understanding the nuclear fuel engineering process and the safe geological disposal of radioactive wastes. PMID:22873132

  1. Solvation free energies in [bmim]-based ionic liquids: Anion effect toward solvation of amino acid side chain analogues

    Science.gov (United States)

    Latif, Muhammad Alif Mohammad; Micaêlo, Nuno; Abdul Rahman, Mohd Basyaruddin

    2014-11-01

    Stochastic molecular dynamics simulations were performed to investigate the solvation free energy of 15 neutral amino acid side chain analogues in aqueous and five, 1-butyl-3-methylimidazolium ([BMIM])-based ionic liquids. The results in aqueous were found highly correlated with previous experimental and simulation data. Meanwhile, [BMIM]-based RTILs showed better solvation thermodynamics than water to an extent that they were capable of solvating molecules immiscible in water. Non-polar analogues showed stronger solvation in hydrophobic RTIL anions such as [PF6]- and [Tf2N]- while polar analogues showed stronger solvation in the more hydrophilic RTIL anions such as [Cl]-, [TfO]- and [BF4]-.

  2. Electrodeposition of ruthenium, rhodium and palladium from nitric acid and ionic liquid media: Recovery and surface morphology of the deposits

    International Nuclear Information System (INIS)

    Research highlights: → Platinum group metals are man-made noble metals. → Electrochemical recovery of fission platinoids. → Recovery from nitric acid medium. → Recovery from ionic liquid medium. → Platinoids with exotic surface morphologies. - Abstract: Electrodeposition is a promising technique for the recovery of platinum group metals with unique surface morphologies. The electrodeposition of palladium, ruthenium and rhodium from aqueous nitric acid, and non-aqueous 1-butyl-3-methylimidazolium chloride ionic liquid medium was studied at stainless steel electrode. The surface morphology and elemental composition of the resultant deposit were probed by scanning electron microscopy (SEM) and energy dispersive X-ray (EDS) analysis. Deposits with diverse surface morphologies and metal compositions were obtained by varying the composition of the electrolytic medium and applied potential. The results demonstrate the possibility of tailoring the morphologies of PGMs by controlling the composition and potential needed for electrodeposition.

  3. Inclusion complex formation of ionic liquids with 4-sulfonatocalixarenes studied by competitive binding of berberine alkaloid fluorescent probe

    Science.gov (United States)

    Miskolczy, Zsombor; Biczók, László

    2009-07-01

    A clinically important natural isoquinoline alkaloid, berberine, was used as a fluorescent probe to study the encapsulation of 1-alkyl-3-methylimidazolium (C nMIm +) type ionic liquids in 4-sulfonato-substituted calix[4]arene (SCX4) and calix[6]arene (SCX6) at pH 2. Addition of ionic liquids to the aqueous solution of berberine-SCXn inclusion complexes brought about considerable fluorescence intensity diminution due to the extrusion of berberine from the macrocycle into the aqueous phase by the competitive inclusion of C nMIm + cation. The lengthening of the aliphatic side chain of the imidazolium moiety diminished the equilibrium constant of complexation with SCX4, but enhanced the stability of SCX6 complexes. Larger binding strength was found for SCX4.

  4. Solubility and first hydrolysis constants of europium at different ionic strength and 303 K

    International Nuclear Information System (INIS)

    The solubility of europium at 0.02M, 0.1M and 0.7M NaClO4 ionic strength solutions was determined by a radiometric method and pEus-pCH diagrams were obtained. Hydrolysis constants were also determined at the same ionic strengths by pH titration and the values found were log *β1 -7.68±0.11, -8.07±0.10 and -8.20±0.11. The log Ksp values were -23.5±0.2, -22.7±0.2 and -21.9±0.2 for 0.02M, 0.1M and 0.7M NaClO4 ionic strengths, respectively, at 303 K under CO2-free conditions and the extrapolated value at zero ionic strength was log Ksp0 = -24.15. The working pCH ranges for the calculation of the hydrolysis constants were selected from the pEus-pCH diagrams in the region where precipitation of europium oxide or hydroxide was less than 20%. Europium removal from aqueous solutions with zeolites was explored. (author)

  5. Lyotropic Phase Behavior of Polybutadiene-Poly(ethylene oxide) Diblock Copolymers in Ionic Liquids

    Energy Technology Data Exchange (ETDEWEB)

    Simone, Peter M.; Lodge, Timothy P. (UMM)

    2008-08-26

    The lyotropic phase behavior of three poly(1,2-butadiene-b-ethylene oxide) diblock copolymers (PB-PEO) with different monomer volume fractions has been studied in two different ionic liquids, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMI][TFSI]) and 1-butyl-3-methylimidazolium hexafluorophosphate ([BMI][PF{sub 6}]), across the complete concentration range. The ordered microstructures present in the solutions were characterized via small-angle X-ray scattering (SAXS). The phase diagrams for the PB-PEO/ionic liquid solutions include regions corresponding to the classical copolymer microstructures: body-centered-cubic lattices of spheres, hexagonally ordered cylinders, and lamellae. Additionally, the phase diagrams also include wide regions of coexisting microstructures and regions apparently corresponding to a disordered network microstructure. The phase behavior of the PB-PEO copolymers in both ionic liquids was comparable to their previously reported aqueous solution behavior. The temperature dependence of the phase diagrams was very modest, indicative of a highly segregated system. The level of solvent selectivity was also investigated via cryogenic transmission electron microscopy (cryo-TEM) on dilute solutions. On the basis of the morphology of the dilute solution copolymer aggregate structures in the ionic liquid solvents, and on the structural length scales of the concentrated solutions, it was concluded that for PB-PEO [BMI][PF{sub 6}] behaves as a more selective solvent than [EMI][TFSI].

  6. Clinical cardiovascular experiences with iopamidol: a new non-ionic contrast medium.

    Science.gov (United States)

    Partridge, J B; Robinson, P J; Turnbull, C M; Stoker, J B; Boyle, R M; Morrison, G W

    1981-07-01

    Iopamidol, a new non-ionic water-soluble contrast medium, has been compared with standard ionic media in a number of cardiovascular applications. It is stable in aqueous solution, is much less viscous and only slightly more osmolar than metrizamide. Compared to sodium meglumine diatrizoate in a series of 40 coronary arteriograms, it produced a consistent and highly significant decrease in the incidence and severity of hypotension and bradycardia following intracoronary injection. In the same group and in 62 children undergoing ventricular or great vessel angiocardiography, a subjective assessment of patient reaction showed that iopamidol was better tolerated than the ionic medium. There was a very strong patient preference for iopamidol in a group of 20 of the adult patients who had also consented to femoral artery injections of both media. Throughout these series there was no detectable difference in arterial image quality between the media. Venous phase opacification during arterioportography was assessed in 11 cases comparing iopamidol with sodium meglumine iothalamate. No significant difference was found. We conclude that iopamidol is clearly preferable to ionic media for routine cardiovascular applications.

  7. NOvel Fission Product Separation Based on Room-Temperature Ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Hussey, Charles L.

    2005-11-13

    The effective extraction of Cs+ and Sr2+ into a relatively new and heretofore untested hydrophobic ionic liquid, tri-n-butylmethylammonium bis[(trifluoromethyl)sulfonyl]imide was demonstrated with calix[4]arene-bis(tert-octylbenzo-crown-6) and dicyclohexano-18-crown-6, respectively. The coordinated Cs+ and Sr2+ were subsequently removed from the ionic liquid extraction solvent by an electrochemical reduction process carried out at mercury electrodes. This process is non-destructive, permitting the ionic liquid and ionophores to be recycled. Although the process is based on mercury electrodes, this is a benefit rather than a detriment because the liquid mercury containing the Cs and Sr can be easily transported to another electrochemical cell where the Cs and Sr could be electrochemically recovered from the mercury amalgam and concentrated into a minimum volume of water or some other inexpensive solvent. This should facilitate the development of a suitable waste form for the extracted Cs+ and Sr2+. Thus, the feasibility of the proposed ionic liquid-based extraction cycle for the removal of 137Cs+ and 90Sr2+ from simulated aqueous tank waste was demonstrated.

  8. Capacitance of Ti3C2Tx MXene in ionic liquid electrolyte

    Science.gov (United States)

    Lin, Zifeng; Barbara, Daffos; Taberna, Pierre-Louis; Van Aken, Katherine L.; Anasori, Babak; Gogotsi, Yury; Simon, Patrice

    2016-09-01

    Ti3C2Tx MXene, a two-dimensional (2D) early transition metal carbide, has shown an extremely high volumetric capacitance in aqueous electrolytes, but in a narrow voltage window (less than 1.23 V). The utilization of MXene materials in ionic liquid electrolytes with a large voltage window has never been addressed. Here, we report the preparation of the Ti3C2Tx MXene ionogel film by vacuum filtration for use as supercapacitor electrodes operating in 1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMI-TFSI) neat ionic liquid electrolyte. Due to the disordered structure of the Ti3C2Tx hydrogel film and a stable spacing after vacuum drying, achieved through ionic liquid electrolyte immersion of the Ti3C2Tx hydrogel film, the Ti3C2Tx surface became accessible to EMI+ and TFSI- ions. A capacitance of 70 F g-1 together with a large voltage window of 3 V was obtained at a scan rate of 20 mV s-1 in neat EMI-TFSI electrolyte. The electrochemical signature indicates a capacitive behavior even at a high scan rate (500 mV s-1) and a high power performance. This work opens up the possibilities of using MXene materials with various ionic liquid electrolytes.

  9. A computer program for geochemical analysis of acid-rain and other low-ionic-strength, acidic waters

    Science.gov (United States)

    Johnsson, P.A.; Lord, D.G.

    1987-01-01

    ARCHEM, a computer program written in FORTRAN 77, is designed primarily for use in the routine geochemical interpretation of low-ionic-strength, acidic waters. On the basis of chemical analyses of the water, and either laboratory or field determinations of pH, temperature, and dissolved oxygen, the program calculates the equilibrium distribution of major inorganic aqueous species and of inorganic aluminum complexes. The concentration of the organic anion is estimated from the dissolved organic concentration. Ionic ferrous iron is calculated from the dissolved oxygen concentration. Ionic balances and comparisons of computed with measured specific conductances are performed as checks on the analytical accuracy of chemical analyses. ARCHEM may be tailored easily to fit different sampling protocols, and may be run on multiple sample analyses. (Author 's abstract)

  10. Suppressing the dendritic growth of zinc in an ionic liquid containing cationic and anionic zinc complexes for battery applications.

    Science.gov (United States)

    Liu, Zhen; Pulletikurthi, Giridhar; Lahiri, Abhishek; Cui, Tong; Endres, Frank

    2016-05-10

    Metallic zinc is a promising negative electrode for high energy rechargeable batteries due to its abundance, low-cost and non-toxic nature. However, the formation of dendritic zinc and low Columbic efficiency in aqueous alkaline solutions during charge/discharge processes remain a great challenge. Here we demonstrate that the dendritic growth of zinc can be effectively suppressed in an ionic liquid electrolyte containing highly concentrated cationic and anionic zinc complexes obtained by dissolving zinc oxide and zinc trifluoromethylsulfonate in a protic ionic liquid, 1-ethylimidazolium trifluoromethylsulfonate. The presence of both cationic and anionic zinc complexes alters the interfacial structure at the electrode/electrolyte interface and influences the nucleation and growth of zinc, leading to compact, homogeneous and dendrite-free zinc coatings. This study also provides insights into the development of highly concentrated metal salts in ionic liquids as electrolytes to deposit dendrite-free zinc as an anode material for energy storage applications. PMID:27080261

  11. Task-Specific Ionic Liquids for Mars Exploration (Green Chemistry for a Red Planet)

    Science.gov (United States)

    Karr, L. J.; Curreri, P. A.; Paley, M. S.; Kaukler, W. F.; Marone, M. J.

    2012-01-01

    Ionic Liquids (ILs) are organic salts with low melting points that are liquid at or near room temperature. The combinations of available ions and task-specific molecular designability make them suitable for a huge variety of tasks. Because of their low flammability, low vapor pressure, and stability in harsh environments (extreme temperatures, hard vacuum) they are generally much safer and "greener" than conventional chemicals and are thus suitable for a wide range of applications that support NASA exploration goals. This presentation describes several of the ongoing applications that are being developed at MSFC.

  12. Influence of purity of NdF3 single crystals on their ionic conductivity

    Science.gov (United States)

    Sorokin, N. I.; Zhmurova, Z. I.; Krivandina, E. A.; Sobolev, B. P.

    2012-05-01

    Single crystals of the NdF3 superionic conductor have been grown by the Bridgman method from a melt in a helium atmosphere using a fluorinating PbF2 agent. Commercial NdF3 reagents of special purity grade, reagent grade, and pure grade are used. It is found that the ionic conductivity σ of the crystals depends considerably on the purity grade of the starting substances: at 200°C σ = 1.4 × 10-, 3 × 10-4, and 8 × 10-4 S/cm for reagents of special purity grade, reagent grade, and pure grade, respectively.

  13. Olefins hydro-formylation catalysed by rhodium complexes using ionic liquids; Hydroformylation des olefines par les complexes du rhodium dans les liquides ioniques

    Energy Technology Data Exchange (ETDEWEB)

    Favre, F.

    2000-10-26

    Biphasic long chain olefins hydro-formylation catalysed by rhodium complexes using ionic liquids allows a selective reaction and an easy separation of the products from the catalyst. This study reports the synthesis of ionic liquids that were used as the catalyst's solvent. Their physical and chemical properties (melting point, solubility of organic substrates) can be varied with the structure of the organic cation (imidazolium, pyridinium, pyrrolydinium) and with its substituents (nature, length, number). It depends also on the nature of the inorganic anion (hexa-fluoro-phosphate, tetrafluoroborate, tri-fluoro-acetate, triflate, bistriflylamidure...). The use of phosphorus ligands bearing ionic functions proved to be efficient to maintain the onerous rhodium catalyst in the ionic liquid phase. Phosphines, phosphites and phosphinites including anionic (sulfonate, carboxylate) or cationic (imidazolium, pyridinium, guanidinium, phosphonium) groups have been synthesised. Finally, the influences of the ligand and of the ionic liquid on the catalytic system performances are described. Selectivities in aldehydes and reaction rates proved to be highly dependent on the nature of the ligand and of the ionic liquid. The different possibilities of recycling the ionic phase containing the rhodium catalyst have been also studied. (author)

  14. Copolymer Melts in Disordered Media

    OpenAIRE

    Stepanow, S.; Dobrynin, A.; Vilgis, T.; Binder, K.

    1996-01-01

    We have considered a symmetric AB block copolymer melt in a gel matrix with preferential adsorption of A monomers on the gel. Near the point of the microphase separation transition such a system can be described by the random field Landau-Brazovskii model, where randomness is built into the system during the polymerization of the gel matrix. By using the technique of the 2-nd Legendre transform, the phase diagram of the system is calculated. We found that preferential adsorption of the copoly...

  15. Crowding and Anomalous Capacitance at an Electrode–Ionic Liquid Interface Observed Using Operando X-ray Scattering

    OpenAIRE

    Chu, Miaoqi; Miller, Mitchell; Dutta, Pulak

    2016-01-01

    Room temperature ionic liquids are widely recognized as novel electrolytes with properties very different from those of aqueous solutions, and thus with many potential applications, but observing how they actually behave at electrolytic interfaces has proved to be challenging. We have studied the voltage-dependent structure of [TDTHP]+[NTF2]− near its interface with an electrode, using in situ synchrotron X-ray reflectivity. An anion-rich layer develops at the interface above a threshold volt...

  16. Compatibilization of HDPE/agar biocomposites with eutectic-based ionic liquid containing surfactant

    CERN Document Server

    Shamsuri, AA; Zainudin, ES; Tahir, PM

    2014-01-01

    In this research, eutectic-based ionic liquid specifically choline chloride/glycerol was prepared at a 1:2 mole ratio. The choline chloride/glycerol was added with the different content of surfactant (hexadecyltrimethylammonium bromide). The choline chloride/glycerol-hexadecyltrimethylammonium bromide was introduced into high-density polyethylene/agar biocomposites through melt mixing. The mechanical testing results indicated that the impact strength and tensile extension of the biocomposites increased with the introduction of the choline chloride/glycerol-hexadecyltrimethylammonium bromide. The scanning electron microscope, differential scanning calorimetry and thermal gravimetric analysis results exhibited that significant decrease in the number of agar fillers pull-out, melting point and thermal decomposition temperatures of the biocomposites are also due to the choline chloride/glycerol-hexadecyltrimethylammonium bromide. The Fourier transform infrared spectra and X-ray diffractometer patterns of the bioc...

  17. Accounting for Electronic Polarization Effects in Aqueous Sodium Chloride via Molecular Dynamics Aided by Neutron Scattering.

    Science.gov (United States)

    Kohagen, Miriam; Mason, Philip E; Jungwirth, Pavel

    2016-03-01

    Modeled ions, described by nonpolarizable force fields, can suffer from unphysical ion pairing and clustering in aqueous solutions well below their solubility limit. The electronic continuum correction takes electronic polarization effects of the solvent into account in an effective way by scaling the charges on the ions, resulting in a much better description of the ionic behavior. Here, we present parameters for the sodium ion consistent with this effective polarizability approach and in agreement with experimental data from neutron scattering, which could be used for simulations of complex aqueous systems where polarization effects are important.

  18. Quantized friction across ionic liquid thin films.

    Science.gov (United States)

    Smith, Alexander M; Lovelock, Kevin R J; Gosvami, Nitya Nand; Welton, Tom; Perkin, Susan

    2013-10-01

    Ionic liquids - salts in the liquid state under ambient conditions - are of great interest as precision lubricants. Ionic liquids form layered structures at surfaces, yet it is not clear how this nano-structure relates to their lubrication properties. We measured the friction force between atomically smooth solid surfaces across ionic liquid films of controlled thickness in terms of the number of ion layers. Multiple friction-load regimes emerge, each corresponding to a different number of ion layers in the film. In contrast to molecular liquids, the friction coefficients differ for each layer due to their varying composition. PMID:23942943

  19. Ionic conduction in alkali metal doped ZnFe/sub 2/O/sub 4/ compound

    International Nuclear Information System (INIS)

    Zinc ferric oxide (ZnFe/sub 2/O/sub 4/) has been synthesized by liquid phase chemical reaction from aqueous mixture of zinc chloride and ferric chloride in sodium hydroxide (4N) solution and effect of alkali metal on electrical characteristics was explored. The well characterized powder was pressed into pellets and dried at 80 degree C. Samples with alkali metal concentrations 10-100 ppm have been investigated to I-V measurements. The conductivity of pure compound (10-/sub 2/omega-cm)/sup-1/) lies in the semiconductor range but due to alkali metal doping the compound shows ionic conduction at room temperature. The ionic conduction is found to be increased as the dopant concentration increases.(author)

  20. Rheological properties of concentrated solutions of gelatin in an ionic liquid 1-ethyl-3-methylimidazolium dimethyl phosphate.

    Science.gov (United States)

    Horinaka, Jun-Ichi; Okamoto, Arisa; Takigawa, Toshikazu

    2016-10-01

    Rheological properties of gelatin solutions were examined in concentrated regions. Gelatin species from porcine skin and from bovine bone were dissolved in an ionic liquid 1-ethyl-3-methylimidazolium dimethyl phosphate. The dynamic viscoelasticity data for the solutions exhibited rubbery plateaus, indicating the existence of entanglement coupling between gelatin chains in the solutions. From the analogy with rubber elasticity, assuming that the molecular weight between entanglements (Me) is the average mesh size of the entanglement network, Me for gelatin in the solutions were determined from the heights of the rubbery plateaus. Then the value of Me in the molten state (Me,melt), a material constant reflecting the chemical structure of polymer species, for gelatin was estimated to be 8.7×10(3). Compared to synthetic polyamides whose Me,melt were known, Me,melt for gelatin was significantly larger, which could be explained by the densely repeating amide bonds composing gelatin. PMID:27311506

  1. Alkaline ionic liquids applied in supported ionic liquid catalyst for selective hydrogenation of citral to citronellal

    Science.gov (United States)

    Salminen, Eero; Virtanen, Pasi; Mikkola, Jyri-Pekka

    2014-02-01

    The challenge in preparation of ionic liquids containing a strong alkaline anion is to identify a suitable cation which can tolerate the harsh conditions induced by the anion. In this study, a commercial quaternary ammonium compound (quat) benzalkonium [ADBA] (alkyldimethylbenzylammonium) was used as a cation in the synthesis of different alkaline ionic liquids. In fact, the precursor, benzalkonium chloride, is a mixture of alkyldimethylbenzylammonium chlorides of various alkyl chain lengths and is commonly used in the formulation of various antiseptic products. The prepared ionic liquids were utilized as Supported Ionic Liquid Catalysts (SILCAs). Typically, a SILCA contains metal nanoparticles, enzymes or metal complexes in an ionic liquid layer which is immobilized on a solid carrier material such as an active carbon cloth (ACC). The catalysts were applied in the selective hydrogenation of citral to citronellal which is an important perfumery chemical. Interestingly, 70 % molar yield towards citronellal was achieved over a catalyst containing the alkaline ionic liquid benzalkonium methoxide.

  2. Alkaline ionic liquids applied in supported ionic liquid catalyst for selective hydrogenation of citral to citronellal

    Directory of Open Access Journals (Sweden)

    Eero eSalminen

    2014-02-01

    Full Text Available The challenge in preparation of ionic liquids containing a strong alkaline anion is to identify a suitable cation which can tolerate the harsh conditions induced by the anion. In this study, a commercial quaternary ammonium compound (quat benzalkonium [ADBA] (alkyldimethylbenzylammonium was used as a cation in the synthesis of different alkaline ionic liquids. In fact, the precursor, benzalkonium chloride, is a mixture of alkyldimethylbenzylammonium chlorides of various alkyl chain lengths and is commonly used in the formulation of various antiseptic products. The prepared ionic liquids were utilized as Supported Ionic Liquid Catalysts (SILCAs. Typically, a SILCA contains metal nanoparticles, enzymes or metal complexes in an ionic liquid layer which is immobilized on a solid carrier material such as an active carbon cloth (ACC. The catalysts were applied in the selective hydrogenation of citral to citronellal which is an important perfumery chemical. Interestingly, 70 % molar yield towards citronellal was achieved over a catalyst containing the alkaline ionic liquid benzalkonium methoxide.

  3. Melting a Sample within TEMPUS

    Science.gov (United States)

    2003-01-01

    One of the final runs of the TEMPUS experiment shows heating of a sample on STS-94, July 15, 1997, MET:14/11:01 (approximate) and the flows on the surface. At the point this image was taken, the sample was in the process of melting. The surface of the sample is begirning to flow, looking like the motion of plate tectonics on the surface of a planet. During this mission, TEMPUS was able to run than 120 melting cycles with zirconium, with a maximum temperature of 2,000 degrees C, and was able to undercool by 340 degrees -- the highest temperature and largest undercooling ever achieved in space. The TEMPUS investigators also have provided the first measurements of viscosity of palladium-silicon alloys in the undercooled liquid alloy which are not possible on Earth. TEMPUS (stands for Tiegelfreies Elektromagnetisches Prozessiere unter Schwerelosigkeit (containerless electromagnetic processing under weightlessness). It was developed by the German Space Agency (DARA) for flight aboard Spacelab. The DARA project scientist was Igon Egry. The experiment was part of the space research investigations conducted during the Microgravity Science Laboratory-1R mission (STS-94, July 1-17 1997). DARA and NASA are exploring the possibility of flying an advanced version of TEMPUS on the International Space Station.(176KB JPEG, 1350 x 1516 pixels; downlinked video, higher quality not available) The MPG from which this composite was made is available at http://mix.msfc.nasa.gov/ABSTRACTS/MSFC-0300193.html.

  4. Dynamical meson melting in holography

    International Nuclear Information System (INIS)

    We discuss mesons in thermalizing gluon backgrounds in the N=2 supersymmetric QCD using the gravity dual. We numerically compute the dynamics of a probe D7-brane in the Vaidya-AdS geometry that corresponds to a D3-brane background thermalizing from zero to finite temperatures by energy injection. In static backgrounds, it has been known that there are two kinds of brane embeddings where the brane intersects the black hole or not. They correspond to the phases with melted or stable mesons. In our dynamical setup, we obtain three cases depending on final temperatures and injection time scales. The brane stays outside of the black hole horizon when the final temperature is low, while it intersects the horizon and settles down to the static equilibrium state when the final temperature is high. Between these two cases, we find the overeager case where the brane dynamically intersects the horizon although the final temperature is not high enough for a static brane to intersect the horizon. The interpretation of this phenomenon in the dual field theory is meson melting due to non-thermal effects caused by rapid energy injection. In addition, we comment on the late time evolution of the brane and a possibility of its reconnection

  5. Monitoring of polymer melt processing

    International Nuclear Information System (INIS)

    The paper reviews the state-of-the-art of in-line and on-line monitoring during polymer melt processing by compounding, extrusion and injection moulding. Different spectroscopic and scattering techniques as well as conductivity and viscosity measurements are reviewed and compared concerning their potential for different process applications. In addition to information on chemical composition and state of the process, the in situ detection of morphology, which is of specific interest for multiphase polymer systems such as polymer composites and polymer blends, is described in detail. For these systems, the product properties strongly depend on the phase or filler morphology created during processing. Examples for optical (UV/vis, NIR) and ultrasonic attenuation spectra recorded during extrusion are given, which were found to be sensitive to the chemical composition as well as to size and degree of dispersion of micro or nanofillers in the polymer matrix. By small-angle light scattering experiments, process-induced structures were detected in blends of incompatible polymers during compounding. Using conductivity measurements during extrusion, the influence of processing conditions on the electrical conductivity of polymer melts with conductive fillers (carbon black or carbon nanotubes) was monitored. (topical review)

  6. Viscosity model for aluminosilicate melt

    Directory of Open Access Journals (Sweden)

    Zhang G.H.

    2012-01-01

    Full Text Available The structurally based viscosity model proposed in our previous study is extended to include more components, e.g. SiO2, Al2O3, FeO, MnO, MgO, CaO, Na2O and K2O. A simple method is proposed to calculate the numbers of different types of oxygen ions classified by the different cations they bonded with, which is used to characterize the influence of composition on viscosity. When dealing with the aluminosilicate melts containing several basic oxides, the priority order is established for different cations for charge compensating Al3+ ions, according to the coulombic force between cation and oxygen anion. It is indicated that basic oxides have two paradox influences on viscosity: basic oxide with a higher basicity decreases viscosity more greatly by forming weaker non-bridging oxygen bond; while it increases viscosity more greatly by forming stronger bridging oxygen bond in tetrahedron after charge compensating Al3+ ion. The present model can extrapolate its application range to the system without SiO2. Furthermore, it could also give a satisfy interpretation to the abnormal phenomenon that viscosity increases when adding K2O to CaO-Al2O3-SiO2 melt within a certain composition range.

  7. Double melting in polytetrafluoroethylene {gamma}-irradiated above its melting point

    Energy Technology Data Exchange (ETDEWEB)

    Serov, S.A., E-mail: servo@nifhi.ru [Karpov Institute of Physical Chemistry, Vorontsovo Pole Street 10, Moscow 105064 (Russian Federation); Khatipov, S.A.; Sadovskaya, N.V.; Tereshenkov, A.V.; Chukov, N.A. [Karpov Institute of Physical Chemistry, Vorontsovo Pole Street 10, Moscow 105064 (Russian Federation)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer PTFE irradiation leads to formation of double melting peaks in DSC curves. Black-Right-Pointing-Pointer This is connected to dual crystalline morphology typical for PTFE. Black-Right-Pointing-Pointer Two crystalline types exist in the PTFE irradiated in the melt. - Abstract: PTFE irradiation above its melting point leads to formation of double melting and crystallization peaks in DSC curves. Splitting of melting peaks is connected to dual crystalline morphology typical for PTFE irradiated in the melt. According to electron microscopy, two crystalline types with different size and packing density exist in the irradiated PTFE.

  8. Tuning Cationic Block Copolymer Micelle Size by pH and Ionic Strength.

    Science.gov (United States)

    Sprouse, Dustin; Jiang, Yaming; Laaser, Jennifer E; Lodge, Timothy P; Reineke, Theresa M

    2016-09-12

    The formation, morphology, and pH and ionic strength responses of cationic block copolymer micelles in aqueous solutions have been examined in detail to provide insight into the future development of cationic micelles for complexation with polyanions such as DNA. Diblock polymers composed of a hydrophilic/cationic block of N,N-dimethylaminoethyl methacrylate (DMAEMA) and a hydrophobic/nonionic block of n-butyl methacrylate (BMA) were synthesized [denoted as DMAEMA-b-BMA (X-Y), where X = DMAEMA molecular weight and Y = molecular weight of BMA in kDa]. Four variants were created with block molecular weights of 14-13, 14-23, 27-14, 27-29 kDa and low dispersities less than 1.10. The amphiphilic polymers self-assembled in aqueous conditions into core-shell micelles that ranged in size from 25-80 nm. These cationic micelles were extensively characterized in terms of size and net charge in different buffers over a wide range of ionic strength (0.02-1 M) and pH (5-10) conditions. The micelle core is kinetically trapped, and the corona contracts with increasing pH and ionic strength, consistent with previous work on micelles with glassy polystyrene cores, indicating that the corona properties are independent of the dynamics of the micelle core. The contraction and extension of the corona scales with solution ionic strength and charge fraction of the amine groups. The aggregation numbers of the micelles were obtained by static light scattering, and the Rg/Rh ratios are close to that of a hard sphere. The zeta potentials of the micelles were positive up to two pH units above the corona pKa, suggesting that applications relying on micelle charge for stability should be viable over a wide range of solution conditions. PMID:27487088

  9. ISOLATION OF URANIUM(VI) AND THORIUM(IV) FROM AQUEOUS SOLUTIONS BY INORGANIC SORBENTS

    OpenAIRE

    Menchuk, V. V.; Perlova, N. A.

    2016-01-01

    Efficiency of use of a new sorbent on the basis of a silica gel at uranium and thorium isolation from their diluted aqueous solutions was investigated. It is shown that the investigated sorbent sorbs uranium and thorium better than a known sorbent (the silica gel). Influence of phases contact time, pH, the metal nature and solution ionic composition on the efficiency of uranium and thorium sorption process was studied. Experimentally received isotherms sorption are described by means of Langm...

  10. Transient melting of an ESR electrode

    Science.gov (United States)

    Kharicha, A.; Karimi-Sibaki, E.; Bohacek, J.; Wu, M.; Ludwig, A.

    2016-07-01

    Melting parameters of ESR process such as melt rate and immersion depth of electrode are of great importance. In this paper, a dynamic mesh based simulation framework is proposed to model melt rate and shape of electrode during the ESR process. Coupling interactions between turbulent flow, temperature, and electromagnetic fields are fully considered. The model is computationally efficient, and enables us to directly calculate melting parameters. Furthermore, dynamic change of electrode shape by melting can be captured. It is necessary to control the feeding velocity of electrode due to melting instabilities in the ESR process. As such, a numerical control is implemented based on the immersion depth of electrode to achieve the steady state in the simulation. Furthermore, the modeling result is evaluated against an experiment.

  11. RHEOLOGY FEATURE OF SIMPLE METAL MELT

    Institute of Scientific and Technical Information of China (English)

    C.J. Sun; H.R. Geng; Y.S. Shen; X.Y. Teng; Z.X. Yang

    2007-01-01

    The rheology feature of Sb, Bi melt and alloys was studied using coaxial cylinder high-temperature viscometer. The results showed that the curve of torsion-rotational speed for Sb melt presents a linear relation in all measured temperature ranges, whereas for the Bi melt, the curve presents obvious non-Newtonian feature within the low temperature range and at relative high shear stress. The rheology feature of Sb80Bi20 and Sb20Bi80, alloy melts was well correlated with that of Sb and Bi, respectively. It is considered that the rheology behavior of Sb melt plays a crucial role in Sb80Bi20, alloy and that of Bi melt plays a crucial role in Sb20Bi80 alloy.

  12. Structural relaxation of metallic glass forming melts

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The fragility of superheated melts, M, for 13 kinds of metallic alloys has been evaluated from the data of the dynamic viscosity above their liquidus temperatures. The authors find that the glass forming ability of metallic melts depends on the fragility of superheated melts rather than on the value of viscosity. In the present work the value of fragility is less than 1 for good glass-forming melts but more than 1 for the other melts. The variation rate of atomic coordination number with temperature indicates clearly the relaxation rate of molten structures. The fragility of superheated melts is found in good agreement with the variation rate of the atomic coordination number with temperature.

  13. Chemical and heating treatments of ionic monolayer-protected clusters (IMPCs) with different surface counter anions.

    Science.gov (United States)

    Choo, Hosun; Isaacs, Steven R; Small, Adam; Parmley, Seth; Shon, Young-Seok

    2007-12-01

    This paper shows an in-depth study on the chemical and thermal responses of two ionic monolayer-protected gold clusters (Oct(4)N(+-)Br- and Oct(4)N(+-)O(3)SS-IMPCs). Two IMPCs displayed completely different phase-transfer behaviors when the solutions were in contact with the aqueous solution containing N-(2-mercaptopropionyl)glycine (tiopronin). Not Oct(4)N(+-)O(3)SS-IMPCs but Oct(4)N(+-)Br-IMPCs experienced a facile phase transfer from the organic layer to the aqueous layer, which was resulted from the displacement of ionic ligands by tiopronin monolayers on the gold nanoparticle surface. When the toluene solution containing Oct(4)N(+-)Br-IMPCs was treated with the aqueous solution containing NaCl salts, the UV-vis spectrum of the solution containing Oct(4)N(+-)Br-IMPCs undertook a fast spectral evolution caused by decomposition/agglomeration of IMPCs. In contrast, Oct(4)N(+-)O(3)SS-IMPCs exhibited much higher stability against the NaCl treatments. The Oct(4)N(+-)O(3)SS-IMPCs also displayed a superior thermal stability at relatively high temperature of approximately 110 degrees C. Core size evolutions of Oct(4)N(+-)O(3)SS-IMPCs without a fast decomposition or aggregation of clusters were also observed during solid-state heating treatments at approximately 150 and approximately 200 degrees C. These results support that the presence of different anions clearly affect the overall stability of ionic nanoparticles. The stronger binding property of thiosulfate anions compared to bromide anions with gold nanoparticle surfaces makes Oct(4)N(+-)O(3)SS-IMPCs chemically more inert and thermally more stable. PMID:17719060

  14. Selective gas absorption by ionic liquids

    DEFF Research Database (Denmark)

    Shunmugavel, Saravanamurugan; Kegnæs, Søren; Due-Hansen, Johannes;

    2010-01-01

    Reversible absorption performance for the flue gas components CO 2, NO and SO2 has been tested for several different ionic liquids (ILs) at different temperatures and flue gas compositions. Furthermore, different porous, high surface area carriers have been applied as supports for the ionic liquids...... to obtain Supported Ionic Liquid-Phase (SILP) absorber materials. The use of solid SILP absorbers with selected ILs were found to significantly improve the absorption capacity and sorption dynamics at low flue gas concentration, thus making the applicability of ILs viable in technical, continuous flow...... processes for flue gas cleaning. The results show that CO 2, NO and SO2 can be reversible and selective absorbed using different ILs and that Supported Ionic Liquid-Phase (SILP) absorbers are promising materials for industrial flue gas cleaning. Absorption/desorption dynamics can be tuned by temperatures...

  15. Ionic Liquid Epoxy Composite Cryotanks Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this work is to determine the optimal process for manufacturing lightweight linerless cryogenic storage tanks using ionic liquid epoxy composite...

  16. Ionic liquid-nanoparticle hybrid electrolytes

    KAUST Repository

    Lu, Yingying

    2012-01-01

    We investigate physical and electrochemical properties of a family of organic-inorganic hybrid electrolytes based on the ionic liquid 1-methyl-3-propylimidazolium bis(trifluoromethanesulfone) imide covalently tethered to silica nanoparticles (SiO 2-IL-TFSI). The ionic conductivity exhibits a pronounced maximum versus LiTFSI composition, and in mixtures containing 13.4 wt% LiTFSI, the room-temperature ionic conductivity is enhanced by over 3 orders of magnitude relative to either of the mixture components, without compromising lithium transference number. The SiO 2-IL-TFSI/LiTFSI hybrid electrolytes are thermally stable up to 400°C and exhibit tunable mechanical properties and attractive (4.25V) electrochemical stability in the presence of metallic lithium. We explain these observations in terms of ionic coupling between counterion species in the mobile and immobile (particle-tethered) phases of the electrolytes. © 2012 The Royal Society of Chemistry.

  17. On the pH of Aqueous Attoliter-Volume Droplets

    Science.gov (United States)

    Ramos, Kieran P.; Velpula, Samson S.; Demille, Trevor B.; Pajela, Ryan; Goldner, Lori S.

    Droplets of water dispersed in perfluorinated liquids have widespread use including microfluidics, drug delivery and single-molecule measurements. Perfluorinated liquids are distinctly biocompatible due to their stability, low surface tension, lipophobicity, and hydrophobicity. For this reason, the effect of the perfluorinated surface on droplet contents is usually ignored. However, as the droplet diameter is reduced, we expect that any effect of the water/oil interface on droplet contents will become more obvious. We studied the pH of attoliter-volume aqueous droplets in perfluorinated liquids using pH-sensing fluorescent dyes. Droplets were prepared either by sonication or extrusion from buffer and perfluorinated liquids (FC40 or FC77). A non-ionic surfactant was used to stabilize the droplets. Buffer strength, ionic strength, and pH of the aqueous phase were varied and resulting droplet pH compared to the pH of the buffer from which they were formed. Preliminary data are consistent with a pH in droplets that depends on the concentration of non-ionic surfactant. At low surfactant concentrations, the pH in droplets is distinctly lower than the stock buffer. However, as the concentration of non-ionic surfactant is increased the change in pH decreases. This work was funded by NSF/DBI-1152386.

  18. Are Entangled Polymer Melts Different From Solutions?

    OpenAIRE

    Huang, Qian; Mednova, Olga; Rasmussen, Henrik K.; Skov, Anne Ladegaard; Almdal, Kristoffer; Hassager, Ole

    2012-01-01

    The possible existence of a qualitative difference on extensional steady state viscosity between polymer melts and polymer solutions is still an open question. Recent experiments [1-4] showed the extensional viscosity of both polymer melts and solutions decayed as a function of strain rate with an exponent of -0.5. When the strain rate became higher than the order of inverse Rouse time, the polymer solutions showed an upturn [1, 4]. However, in the same regime for polymer melts, the experimen...

  19. CV and CM chondrite impact melts

    Science.gov (United States)

    Lunning, Nicole G.; Corrigan, Catherine M.; McSween, Harry Y.; Tenner, Travis J.; Kita, Noriko T.; Bodnar, Robert J.

    2016-09-01

    Volatile-rich and typically oxidized carbonaceous chondrites, such as CV and CM chondrites, potentially respond to impacts differently than do other chondritic materials. Understanding impact melting of carbonaceous chondrites has been hampered by the dearth of recognized impact melt samples. In this study we identify five carbonaceous chondrite impact melt clasts in three host meteorites: a CV3red chondrite, a CV3oxA chondrite, and a regolithic howardite. The impact melt clasts in these meteorites respectively formed from CV3red chondrite, CV3oxA chondrite, and CM chondrite protoliths. We identified these impact melt clasts and interpreted their precursors based on their texture, mineral chemistry, silicate bulk elemental composition, and in the case of the CM chondrite impact melt clast, in situ measurement of oxygen three-isotope signatures in olivine. These impact melts typically contain euhedral-subhedral olivine microphenocrysts, sometimes with relict cores, in glassy groundmasses. Based on petrography and Raman spectroscopy, four of the impact melt clasts exhibit evidence for volatile loss: these melt clasts either contain vesicles or are depleted in H2O relative to their precursors. Volatile loss (i.e., H2O) may have reduced the redox state of the CM chondrite impact melt clast. The clasts that formed from the more oxidized precursors (CV3oxA and CM chondrites) exhibit phase and bulk silicate elemental compositions consistent with higher intrinsic oxygen fugacities relative to the clast that formed from a more reduced precursor (CV3red chondrite). The mineral chemistries and assemblages of the CV and CM chondrite impact melt clasts identified here provide a template for recognizing carbonaceous chondrite impact melts on the surfaces of asteroids.

  20. Frictional melting of peridotite and seismic slip

    OpenAIRE

    Del Gaudio, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Di Toro, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Han, R.; Department of Earth and Environmental Sciences, Korea University, Seoul South Korea; Hirose, T.; Kochi Institute for Core Sample Research, JAMSTEC, Kochi, Japan.; Nielsen, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; Shimamoto, T.; Department of Earth and Planetary Systems Science Graduate School of Science Hiroshima University, Higashi-Hiroshima Japan; Cavallo, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia

    2009-01-01

    The evolution of the frictional strength along a fault at seismic slip rates (about 1 m/s) is a key factor controlling earthquake mechanics. At mantle depths, friction-induced melting and melt lubrication may influence earthquake slip and seismological data. We report on laboratory experiments designed to investigate dynamic fault strength and frictional melting processes in mantle rocks. We performed 20 experiments with Balmuccia peridotite in a high-velocity rotary shear appa...

  1. Specific ionic effect for simple and rapid colorimetric sensing assays of amino acids using gold nanoparticles modified with task-specific ionic liquid.

    Science.gov (United States)

    Wu, Datong; Cai, Pengfei; Tao, Zhihao; Pan, Yuanjiang

    2016-01-01

    In this study, a novel task-specific ionic liquid functionalized gold nanoparticle (TSIL-GNP) was successfully prepared and applied in the recognition of amino acids. Particularly, the surface of GNP was modified with the ionic liquid containing carbamido and ester group via thiol, which was characterized by Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The stability of this material in aqueous solution improves apparently and can remain unchanged for more than three months. The effect of pH was also discussed in this study. Attractive ionic interaction would effectively weaken intensity of the covalent coupling between the metal ion and the functional groups of amino acids. Thus, TSIL-GNP was successfully applied to recognizing serine, aspartic acid, lysine, arginine, and histidine in the presence of Cu(2+) through distinctive color changes. Suspension would be generated once a spot of cysteine was added into the GNPs solution. Results indicated that it had a good linear relationship between extinction coefficients and concentration of amino acids in a wide range of 10(-3)-10(-6) M. Moreover, the proposed strategy was successfully used to analyze the histidine in urinary samples. In brief, TSIL-GNP is a suitable substrate for discrimination of five amino acids in a rapid and simple way without sophisticated instruments.

  2. Lanthanides and actinides in ionic liquids

    OpenAIRE

    Binnemans, Koen

    2007-01-01

    This lecture gives an overview of the research possibilities offered by combining f-elements (lanthanides and actinides) with ionic liquids [1] Many ionic liquids are solvents with weakly coordinating anions. Solvation of lanthanide and actinide ions in these solvents is different from what is observed in conventional organic solvents and water. The poorly solvating behavior can also lead to the formation of coordination compounds with low coordination numbers. The solvation of f-elements can...

  3. Ionic liquids behave as dilute electrolyte solutions

    OpenAIRE

    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 contr...

  4. Dynamics of Ion Transport in Ionic Liquids

    OpenAIRE

    Lee, Alpha A.; Kondrat, Svyatoslav; Vella, Dominic; Goriely, Alain

    2015-01-01

    A gap in understanding the link between continuum theories of ion transport in ionic liquids and the underlying microscopic dynamics has hindered the development of frameworks for transport phenomena in these concentrated electrolytes. Here, we construct a continuum theory for ion transport in ionic liquids by coarse graining a simple exclusion process of interacting particles on a lattice. The resulting dynamical equations can be written as a gradient flow with a mobility matrix that vanishe...

  5. Ionic liquids in the synthesis of nanoobjects

    Energy Technology Data Exchange (ETDEWEB)

    Tarasova, Natalia P; Smetannikov, Yurii V; Zanin, A A [Institute of Chemistry and Problems of Sustainable Development D.I.Mendeleev University of Chemical Technology of Russia (Russian Federation)

    2010-08-12

    Data on the usage of the novel green solvents, ionic liquids, in the synthesis of nanoobjects and their stabilization are considered. The information is structured according to the resulting products of the synthetic processes: nanoparticles of noble metals, nanoparticles of non-metals, nanoparticles of metal oxides and chalcogenides, nanocomposites, and highly dispersed polymers. The conclusion is made that the ionic liquids might determine the structure and the properties of the nanoobjects, thus opening new fundamental and technological horizons in nanochemistry.

  6. Ionic liquids in the synthesis of nanoobjects

    Science.gov (United States)

    Tarasova, Natalia P.; Smetannikov, Yurii V.; Zanin, A. A.

    2010-08-01

    Data on the usage of the novel green solvents, ionic liquids, in the synthesis of nanoobjects and their stabilization are considered. The information is structured according to the resulting products of the synthetic processes: nanoparticles of noble metals, nanoparticles of non-metals, nanoparticles of metal oxides and chalcogenides, nanocomposites, and highly dispersed polymers. The conclusion is made that the ionic liquids might determine the structure and the properties of the nanoobjects, thus opening new fundamental and technological horizons in nanochemistry.

  7. Nonionic and ionic surfactants at an interface

    OpenAIRE

    Onuki, Akira

    2008-01-01

    A Ginzburg-Landau theory is presented on surfactants in polar binary mixtures, which aggregate at an interface due to the amphiphilic interaction. They can be ionic surfactants coexisting with counterions. Including the solvation and image interactions and accounting for a finite volume fraction of the surfactant, we obtain their distributions and the electric potential around an interface in equilibrium. The surface tension is also calculated. The distribution of the adsorbed ionic surfactan...

  8. Polarization versus Temperature in Pyridinium Ionic Liquids

    DEFF Research Database (Denmark)

    Chaban, V. V.; Prezhdo, O. V.

    2014-01-01

    Electronic polarization and charge transfer effects play a crucial role in thermodynamic, structural, and transport properties of room-temperature ionic liquids (RTILs). These nonadditive interactions constitute a useful tool for tuning physical chemical behavior of RTILs. Polarization and charge...... interactions changes negligibly between 300 and 900 K, while the average dipole moment increases due to thermal fluctuations of geometries. Our results contribute to the fundamental understanding of electronic effects in the condensed phase of ionic systems and foster progress in physical chemistry...

  9. Study of thioglycosylation in ionic liquids

    Directory of Open Access Journals (Sweden)

    Ragauskas Arthur

    2006-06-01

    Full Text Available Abstract A novel, green chemistry, glycosylation strategy was developed based upon the use of ionic liquids. Research studies demonstrated that thiomethyl glycosides could readily be activated with methyl trifluoromethane sulfonate, using 1-butyl-3-methylimidazolium tetrafluoroborate as a solvent. This green chemistry glycosylation strategy provided disaccharides with typical yields averaging 75%. The ionic liquid solvent could be readily reused for five sequential glycosylation reactions with no impact on product yield.

  10. The Solubility Parameters of Ionic Liquids

    Directory of Open Access Journals (Sweden)

    Andrzej Marciniak

    2010-04-01

    Full Text Available The Hildebrand’s solubility parameters have been calculated for 18 ionic liquids from the inverse gas chromatography measurements of the activity coefficients at infinite dilution. Retention data were used for the calculation. The solubility parameters are helpful for the prediction of the solubility in the binary solvent mixtures. From the solubility parameters, the standard enthalpies of vaporization of ionic liquids were estimated.

  11. Low Melt Height Solidification of Superalloys

    Science.gov (United States)

    Montakhab, Mehdi; Bacak, Mert; Balikci, Ercan

    2016-06-01

    Effect of a reduced melt height in the directional solidification of a superalloy has been investigated by two methods: vertical Bridgman (VB) and vertical Bridgman with a submerged baffle (VBSB). The latter is a relatively new technique and provides a reduced melt height ahead of the solidifying interface. A low melt height leads to a larger primary dendrite arm spacing but a lower mushy length, melt-back transition length, and porosity. The VBSB technique yields up to 38 pct reduction in the porosity. This may improve a component's mechanical strength especially in a creep-fatigue type dynamic loading.

  12. Solute Redistribution in Directional Melting Process

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@The solute redistribution in directional melting process is theoretically studied. Based on quantitative evaluations, uniform solute distribution in liquid and a quasi-steady solute distribution in solid are supposed. The discussion on the solute balance comes to a simple model for the solute redistribution in directional melting process. As an example, the variation of liquid composition during melting process of carbon steel is quantitatively evaluated using the model. Results show that the melting of an alloy starts at solidus temperature, but approaches the liquidus temperature after a very short transient process.

  13. A novel family of green ionic liquids with surface activities

    Institute of Scientific and Technical Information of China (English)

    ZHANG HaiBo; ZHOU XiaoHai; DONG JinFeng; ZHANG GaoYong; WANG CunXin

    2007-01-01

    Ionic liquids have many unique properties as a new and remarkable class of environmental benign solvents, which promises widespread applications in industry and other areas. However, the ionic liquids with surface activity are rarely reported. In this work, a series of novel ionic liquids was synthesized by using N-methyl-2-pyrrolidone and alkyl bromide. The physical properties of this family of ionic liquids have been characterized, which shows that these compounds have ionic liquids characteristics,surface activity and biocompatibility.

  14. Task-specific ionic liquids for solubilizing metal compounds

    OpenAIRE

    Thijs, Ben

    2007-01-01

    The main goal of this PhD thesis was to design new task-specific ionic liquids with the ability to dissolve metal compounds. Despite the large quantity of papers published on ionic liquids, not much is known about the mechanisms of dissolving metals in ionic liquids or about metal-containing ionic liquids. Additionally, many of the commercially available ionic liquids exhibit a very limited solubilizing power for metal compounds, although this is for many applications like electrodeposition a...

  15. Ionic liquid gel materials: applications in green and sustainable chemistry

    OpenAIRE

    Marr, Patricia C.; Marr, Andrew C.

    2016-01-01

    Ionic liquid gel materials offer a way to further utilise ionic liquids in technological applications. Combining the controlled and directed assembly of gels, with the diverse applications of ionic liquids, enables the design of a heady combination of functional tailored materials, leading to the development of task specific / functional ionic liquid gels. This review introduces gels and gel classification, focusing on ionic liquid gels and their potential roles in a more sustainable future. ...

  16. Fast Ignition and Sustained Combustion of Ionic Liquids

    Science.gov (United States)

    Joshi, Prakash B. (Inventor); Piper, Lawrence G. (Inventor); Oakes, David B. (Inventor); Sabourin, Justin L. (Inventor); Hicks, Adam J. (Inventor); Green, B. David (Inventor); Tsinberg, Anait (Inventor); Dokhan, Allan (Inventor)

    2016-01-01

    A catalyst free method of igniting an ionic liquid is provided. The method can include mixing a liquid hypergol with a HAN (Hydroxylammonium nitrate)-based ionic liquid to ignite the HAN-based ionic liquid in the absence of a catalyst. The HAN-based ionic liquid and the liquid hypergol can be injected into a combustion chamber. The HAN-based ionic liquid and the liquid hypergol can impinge upon a stagnation plate positioned at top portion of the combustion chamber.

  17. The structure of ionic liquids

    CERN Document Server

    Gontrani, Lorenzo

    2014-01-01

    This volume describes the most recent findings on the structure of ILs interpreted through cutting-edge experimental and theoretical methods. Research in the field of ionic liquids (ILs) keeps a fast and steady pace. Since these new-generation molten salts first appeared in the chemistry and physics landscape, a large number of new compounds has been synthesized. Most of them display unexpected behaviour and possess stunning properties. The coverage in this book ranges from the mesoscopic structure of ILs to their interaction with proteins. The reader will learn how diffraction techniques (small and large angle X-Ray and neutron scattering, powder methods), X-Ray absorption spectroscopies (EXAFS/XANES), optical methods (IR, RAMAN), NMR and calorimetric methods can help the study of ILs, both as neat liquids and in mixtures with other compounds. It will enable the reader to choose the best method to suit their experimental needs. A detailed survey of theoretical methods, both quantum-chemical and classical, ...

  18. Pseudo-capacitance of nanoporous carbons in pyrrolidinium-based protic ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Mysyk, R.; Raymundo-Pinero, E.; Beguin, F. [CRMD, CNRS-University, 1B rue de la Ferollerie, 45071 Orleans (France); Anouti, M.; Lemordant, D. [Universite Francois Rabelais, Laboratoire PCMB/CIME, Parc de Grandmont, 37200 Tours (France)

    2010-03-15

    Protic ionic liquids (PILs) were used as novel electrolyte for carbon-based supercapacitors. The cyclic voltammograms in three-electrode cells show reversible redox humps, revealing pseudo-faradaic charge transfer. Oxidative treatment of activated carbon enriches the surface functionality and leads to a higher capacitance owing to a stronger pseudo-faradaic contribution. The capacitors using PILs demonstrate a higher voltage window than with aqueous H{sub 2}SO{sub 4}, while keeping the same values of capacitance, and being able to operate at lower temperature. A combination of activated carbons and PILs holds promise for improving the energy characteristics of supercapacitors. (author)

  19. Solid Effect DNP in a Rapid-melt setup.

    Science.gov (United States)

    van Bentum, P J M; Sharma, M; van Meerten, S G J; Kentgens, A P M

    2016-02-01

    Dynamic Nuclear Polarization (DNP) has become a key element in nuclear magnetic resonance (NMR). Recently, we developed a novel approach to DNP enhanced liquid-state NMR based on rapid melting of a solid hyperpolarized sample followed by 'in situ' liquid-state NMR detection. This method allows (1)H detection with fast cycling options for signal averaging. In nonpolar solvents, doped with BDPA radicals, proton enhancement factors were achieved of up to 400. A short recycling delay of about 5s allows for a fast determination of the hyper-polarization dynamics as function of the microwave frequency and power. Here, we use the rapid melt dnp method to study the mechanisms for DNP in the solid phase in more detail. Solid Effect, Cross Effect, Solid Overhauser and Liquid-state (supercritical) Overhauser DNP enhancement can be observed in the same setup. In this paper, we concentrate on Solid Effect DNP observed with both homogeneous narrow line radicals such as BDPA and with wide line anisotropic nitroxide radicals such as TEMPOL. We find indications that BDPA protons play an important role in Solid Effect DNP with this radical. A simplified spin diffusion model for BDPA can give a semi-quantitative description of the enhancements as function of the microwave power and as function of the proton concentration in the solid solution. For aqueous frozen samples we observe a similar Solid Effect DNP enhancement, which is analyzed within the simplified spin diffusion model.

  20. Aqueous alteration on main-belt asteroids

    Science.gov (United States)

    Fornasier, S.; Lantz, C.; Barucci, M.; Lazzarin, M.

    2014-07-01

    The study of aqueous alteration is particularly important for unraveling the processes occurring during the earliest times in Solar System history, as it can give information both on the thermal processes and on the localization of water sources in the asteroid belt, and for the associated astrobiological implications. The aqueous alteration process produces the low temperature (< 320 K) chemical alteration of materials by liquid water which acts as a solvent and produces materials like phyllosilicates, sulphates, oxides, carbonates, and hydroxides. This means that liquid water was present in the primordial asteroids, produced by the melting of water ice by heating sources, very probably by ^{26}Al decay. Hydrated minerals have been found mainly on Mars surface, on primitive main-belt asteroids (C, G, B, F, and P-type, following the classification scheme by Tholen, 1984) and possibly also on few transneptunian objects. Reflectance spectroscopy of aqueous altered asteroids shows absorption features in the 0.6-0.9 and 2.5-3.5-micron regions, which are diagnostic of, or associated with, hydrated minerals. In this work, we investigate the aqueous alteration process on a large sample of 600 visible spectra of C-complex asteroids available in the literature. We analyzed all these spectra in a similar way to characterize the absorption-band parameters (band center, depth, and width) and spectral slope, and to look for possible correlations between the aqueous alteration process and the asteroids taxonomic classes, orbital elements, heliocentric distances, albedo, and sizes. We find that 4.6 % of P, 7.7 % of F, 9.8 % of B, 50.5 % of C, and 100 % of the G-type asteroids have absorption bands in the visible region due to hydrated silicates. Our analysis shows that the aqueous alteration sequence starts from the P-type objects, practically unaltered, and increases through the P → F → B → C → G asteroids, these last being widely aqueously altered, strengthening thus

  1. The partitioning of sulfur and chlorine between andesite melts and magmatic volatiles and the exchange coefficients of major cations

    Science.gov (United States)

    Zajacz, Zoltán; Candela, Philip A.; Piccoli, Philip M.; Sanchez-Valle, Carmen

    2012-07-01

    Andesite melts were equilibrated with an H-O-S-bearing volatile phase to determine the partition coefficients for S and Cl as a function of melt composition and oxygen fugacity. The experiments were conducted in rapid-quench MHC vessel assemblies at 200 MPa and 1000 °C, and over a range of imposed fO2 between NNO-1.2 and NNO+1.8. High fluid/melt mass ratios (∼15) were employed, allowing precise and accurate partition coefficients to be obtained by mass balance calculations. Chlorine exhibits Henrian behavior at ClO-0.5 activities typical for arc magmas, with D Cl volatile/melt = 1.36 ± 0.06 (1σ) below 0.2 wt.% Cl in the melt; at higher ClO-0.5 activities, D Cl volatile/melt increases linearly to 2.11 ± 0.02 at 1 wt.% Cl in the melt. In the volatile phase: FeCl2 ∼ NaCl > KCl ∼ HCl. The determination of cation exchange coefficients for major cations yielded: K K,Na volatile/melt = 1.23 ± 0.10 (1σ) and ∗K Fe,Na volatile/melt = D Fe volatile/melt / D Na volatile/melt = 1.08 ± 0.16 (1σ). Under these conditions, the concentration of HCl in the vapor is negatively correlated with the (Na + K)/(Al + Fe3+) ratio in the melt. Reduced sulfur (S2-) appears to obey Henry's law in andesite melt-volatile system at fH2S below pyrrhotite saturation. The partition coefficient for S at fO2 = NNO-0.5 correlates negatively with the FeO concentration in the melt, changing from 254 ± 25 at 4.0 wt.% FeO to 88 ± 6 at 7.5 wt.% FeO. Pyrrhotite saturation is reached when approximately 3.2 mol% S is present in the volatile phase at fO2 = NNO-0.5. At the sulfide/sulfate transition, the partition coefficient of S drops from 171 ± 23 to 21 ± 1 at a constant FeO content of ∼6 wt.% in the melt. At fO2 = NNO+1.8, anhydrite saturation is reached at ∼3.3 mol% S present in the volatile phase. Aqueous volatiles exsolving from intermediate to mafic magmas can efficiently extract S, and effect its transfer to sites of magmatic-hydrothermal ore deposit formation.

  2. Ionic liquid-based microwave-assisted extraction of rutin from Chinese medicinal plants.

    Science.gov (United States)

    Zeng, Huan; Wang, Yuzhi; Kong, Jinhuan; Nie, Chan; Yuan, Ya

    2010-12-15

    An ionic liquid-based microwave-assisted extraction (ILMAE) method has been developed for the effective extraction of rutin from Chinese medicinal plants including Saururus chinensis (Lour.) Bail. (S. chinensis) and Flos Sophorae. A series of 1-butyl-3-methylimidazolium ionic liquids with different anions were investigated. The results indicated that the characteristics of anions have remarkable effects on the extraction efficiency of rutin and among the investigated ionic liquids, 1-butyl-3-methylimidazolium bromide ([bmim]Br) aqueous solution was the best. In addition, the ILMAE procedures for the two kinds of medicinal herbs were also optimized by means of a series of single factor experiments and an L(9) (3(4)) orthogonal design. Compared with the optimal ionic liquid-based heating extraction (ILHE), marinated extraction (ILME), ultrasonic-assisted extraction (ILUAE), the optimized approach of ILMAE gained higher extraction efficiency which is 4.879 mg/g in S. chinensis with RSD 1.33% and 171.82 mg/g in Flos Sophorae with RSD 1.47% within the shortest extraction time. Reversed phase high performance liquid chromatography (RP-HPLC) with ultraviolet detection was employed for the analysis of rutin in Chinese medicinal plants. Under the optimum conditions, the average recoveries of rutin from S. chinensis and Flos Sophorae were 101.23% and 99.62% with RSD lower than 3%, respectively. The developed approach is linear at concentrations from 42 to 252 mg L(-1) of rutin solution, with the regression coefficient (r) at 0.99917. Moreover, the extraction mechanism of ILMAE and the microstructures and chemical structures of the two researched samples before and after extraction were also investigated. With the help of LC-MS, it was future demonstrated that the two researched herbs do contain active ingredient of rutin and ionic liquids would not influence the structure of rutin.

  3. Enzymatic hydrolysis of penicillin in mixed ionic liquids/water two-phase system.

    Science.gov (United States)

    Jiang, Yangyang; Xia, Hansong; Guo, Chen; Mahmood, Iram; Liu, Huizhou

    2007-01-01

    In this paper, an integrated process involving the mixed ionic liquids/water two-phase system (MILWS) is proposed to improve the efficiency for enzymatic hydrolysis of penicillin G. First, hydrophilic [C4mim]BF4 (1-butyl-3-methylimidazolium tetrafluoraborate) and NaH2PO4 salt form an ionic liquids aqueous two-phase system (ILATPS), which could extract penicillin from its fermentation broth efficiently. Second, a hydrophobic [C4mim]PF6 (1-butyl-3-methylimidazolium hexafluoraphosphate) is introduced into the ionic liquids-rich phase of ILATPS containing penicillin and converses it into MILWS. Penicillin is hydrolyzed by penicillin acylase in the water phase of MILWS at pH 5. The byproduct phenylacetic acid (PAA) is partitioned into the ionic liquids mixture phase, while the intended product 6-aminopenicillanic acid (6-APA) is precipitated at this pH. In comparison with a similar butyl acetate/water system (BAWS) at pH 4, MILWS exhibits two advantages. (1) The selectivity between PAA and penicillin is greatly optimized at pH 5 by varying the mole ratio of [C4mim]PF6/[C4mim]BF4 in MILWS, whereas in BAWS the unalterable nature of the organic solvent restricts the optimized pH for maximum selectivity between PAA and penicillin at pH 4. (2) The pH for 6-APA precipitation in BAWS is 4, whereas it shifts to pH 5 in MILWS due to the complexation between negatively charged 6-APA and the cationic surface of the ionic liquids micelle. As a result, the removal of the two products from the enzyme sphere at relatively high pH is permitted in MILWS, which is beneficial for enzymatic activity and stability in comparison with the acidic pH 4 environment in BAWS.

  4. DNA sensor's selectivity enhancement and protection from contaminating nucleases due to a hydrated ionic liquid.

    Science.gov (United States)

    Tateishi-Karimata, Hisae; Pramanik, Smritimoy; Sugimoto, Naoki

    2015-07-01

    The thermodynamic stability of certain mismatched base pairs has made the development of DNA sequence sensing systems challenging. Thus, the stability of fully matched and mismatched DNA oligonucleotides in the hydrated ionic liquid choline dihydrogen phosphate (choline dhp) was investigated. Mismatched base pairs were significantly destabilized in choline dhp relative to those in aqueous buffer. A molecular beacon that forms a triplex with a conserved HIV-1 sequence was then designed and tested in choline dhp. The molecular beacon specifically detected the target duplex via triplex formation at concentrations as low as 1 pmol per 10 μL with 10,000-fold sequence selectivity. Moreover, the molecular beacon was protected from a contaminating nuclease in choline dhp, and DNAs in aqueous solutions were not sufficiently stable for practical use. PMID:25919083

  5. Dielectric spectra broadening as the signature of dipole-matrix interaction. II. Water in ionic solutions.

    Science.gov (United States)

    Levy, Evgeniya; Puzenko, Alexander; Kaatze, Udo; Ben Ishai, Paul; Feldman, Yuri

    2012-03-21

    In this, the second part of our series on the dielectric spectrum symmetrical broadening of water, we consider ionic aqueous solutions. If in Part I, dipole-dipole interaction was the dominant feature, now ion-dipole interplay is shown to be the critical element in the dipole-matrix interaction. We present the results of high-frequency dielectric measurements of different concentrations of NaCl/KCl aqueous solutions. We observed Cole-Cole broadening of the main relaxation peak of the solvent in the both electrolytes. The 3D trajectory approach (described in detail in Part I) is applied in order to highlight the differences between the dynamics and structure of solutions of salts on one hand and dipolar solutes on the other hand.

  6. Dielectric spectra broadening as the signature of dipole-matrix interaction. II. Water in ionic solutions.

    Science.gov (United States)

    Levy, Evgeniya; Puzenko, Alexander; Kaatze, Udo; Ben Ishai, Paul; Feldman, Yuri

    2012-03-21

    In this, the second part of our series on the dielectric spectrum symmetrical broadening of water, we consider ionic aqueous solutions. If in Part I, dipole-dipole interaction was the dominant feature, now ion-dipole interplay is shown to be the critical element in the dipole-matrix interaction. We present the results of high-frequency dielectric measurements of different concentrations of NaCl/KCl aqueous solutions. We observed Cole-Cole broadening of the main relaxation peak of the solvent in the both electrolytes. The 3D trajectory approach (described in detail in Part I) is applied in order to highlight the differences between the dynamics and structure of solutions of salts on one hand and dipolar solutes on the other hand. PMID:22443773

  7. Solid State Ionic Materials - Proceedings of the 4th Asian Conference on Solid State Ionics

    Science.gov (United States)

    Chowdari, B. V. R.; Yahaya, M.; Talib, I. A.; Salleh, M. M.

    1994-07-01

    SO4 (X=Si, Ge, Ti) Systems * A DSC and Conductivity Study of the Influence of Cesium Ion on the Beta-Alpha Transition in Silver Iodide * Phase Diagrams, Stoichiometries and Properties of Bi4V2O11:M2+ Solid Electrolytes * Physical Properties of Electrodeposited Silver Chromotungstate * Pseudopotential Study of Bonding in the Superionic Material AgI: The Effect of Statistical Distribution of Mobile Ions * Cubic Phase Dominant Region in Submicron BaTiO3 Particles * The Crystallization of CoZr Amorphous Alloys via Electrical Resistivity * Cation Ratio Related Properties of Synthetic Mg/Al Layered Double Hydroxide and it's Nanocomposite * DC Conductivity of Nano-Particles of Silver Iodide * Effect of Anomalous Diffusion on Quasielastic Scattering in Superionic Conductors * Computer Simulation Study of Conductivity Enhancement in Superionic-Insulator Composites * Dynamics of Superionic Silver and Copper Iodide Salt Melts * Influence of Dopant Salt AgI, Glass Modifier Ag2O and Glass Formers (SeO3 + MoO3) on Electrical Conductivity in Quaternary Glassy System * Fast Ion Conductivity in the Presence of Competitive Network Formers * Role of Alkali Ions in Borate Glasses * Inelastic Light Scattering in Cadmium Borate Glasses * Investigation on Transport Properties of Mixed Glass System 0.75 [0.75AgI:0.25AgCl]. 0.25[Ag2O:CrO3] * Conduction Mechanism in Lithium Tellurite Glasses * Optimized Silver Tungstoarsenate Glass Electrolyte * Stabilized Superfine Zirconia Powder Prepared by Sol-Gel Process * Study of New PAN-based Electrolytes * Electrical and Thermal Characterization of PVA based Polymer Electrolytes * Conductive Electroactive Polymers: Versatile Solid State Ionic Materials * The Role of Ag2O Addition on the Superconducting Properties of Y-124 Compound * Absorption Spectra Studies of the C60 Films on Transition Metal Film Substrates * Effect of Alumina Dispersal on the Conductivity and Crystallite Size of Polymer Electrolyte * New Mixed Galss-Polymer Solid Electrolytes

  8. Ionic Liquids in Pharmaceuticals%具有药物活性的离子液体

    Institute of Scientific and Technical Information of China (English)

    杨亭亭; 高国华

    2012-01-01

    In order to solve the problems associated with the solid form of conventional pharmaceuticals including polymorphic conversion, low solubility, low bioavailability, and the tendency of amorphous forms to spontaneously crystallize, the liquid form pharmaceuticals have attracted much attention. Recent developments of ionic liquids (ionic liquids are loosely defined as salts with melting points below 100℃) might prove beneficial. Ionic liquids exhibit controlled solubility, unique surface activity, high thermostability and enhancement in bioavailability or bioactivity, which make ionic liquids have the advantage of elimination of polymorphism, new delivery options, or having customized pharmaceutical cocktails. In some cases, an active cation and an active anion can be combined to produce a liquid possessing dual functionality. These make ionic liquids have the possibility of being used in the pharmaceutical industry. The aim of this mini-review is to summarize the recent development of ionic liquids as active pharmaceutical ingredients, antimicrobial agents and agricuhure chemicals, and discuss the existing problems and the future research of ionic liquids in pharmaceuticals.%离子液体阴阳离子的可设计性使其具有可控溶解性、独特表面活性、高热稳定性、增强的生物利用率和生物活性,这些特点使离子液体在消除同质多晶现象、改变药物传输模式及可包含传统药物组分等方面具有优势,成为当前离子液体研究领域的热点之一。本文对离子液体在医药领域的应用做了全面的阐述,主要介绍了近十年来离子液体在活性药物组分、抗菌剂及除草剂方面的成果,探讨了当前存在的问题及研究方向,并对其应用做了展望。

  9. A benchmark initiative on mantle convection with melting and melt segregation

    Science.gov (United States)

    Schmeling, Harro; Dannberg, Juliane; Dohmen, Janik; Kalousova, Klara; Maurice, Maxim; Noack, Lena; Plesa, Ana; Soucek, Ondrej; Spiegelman, Marc; Thieulot, Cedric; Tosi, Nicola; Wallner, Herbert

    2016-04-01

    In recent years a number of mantle convection models have been developed which include partial melting within the asthenosphere, estimation of melt volumes, as well as melt extraction with and without redistribution at the surface or within the lithosphere. All these approaches use various simplifying modelling assumptions whose effects on the dynamics of convection including the feedback on melting have not been explored in sufficient detail. To better assess the significance of such assumptions and to provide test cases for the modelling community we carry out a benchmark comparison. The reference model is taken from the mantle convection benchmark, cases 1a to 1c (Blankenbach et al., 1989), assuming a square box with free slip boundary conditions, the Boussinesq approximation, constant viscosity and Rayleigh numbers of 104 to 10^6. Melting is modelled using a simplified binary solid solution with linearly depth dependent solidus and liquidus temperatures, as well as a solidus temperature depending linearly on depletion. Starting from a plume free initial temperature condition (to avoid melting at the onset time) five cases are investigated: Case 1 includes melting, but without thermal or dynamic feedback on the convection flow. This case provides a total melt generation rate (qm) in a steady state. Case 2 is identical to case 1 except that latent heat is switched on. Case 3 includes batch melting, melt buoyancy (melt Rayleigh number Rm) and depletion buoyancy, but no melt percolation. Output quantities are the Nusselt number (Nu), root mean square velocity (vrms), the maximum and the total melt volume and qm approaching a statistical steady state. Case 4 includes two-phase flow, i.e. melt percolation, assuming a constant shear and bulk viscosity of the matrix and various melt retention numbers (Rt). These cases are carried out using the Compaction Boussinseq Approximation (Schmeling, 2000) or the full compaction formulation. For cases 1 - 3 very good agreement

  10. Squeezout phenomena and boundary layer formation of a model ionic liquid under confinement and charging

    Science.gov (United States)

    Capozza, R.; Vanossi, A.; Benassi, A.; Tosatti, E.

    2015-02-01

    Electrical charging of parallel plates confining a model ionic liquid down to nanoscale distances yields a variety of charge-induced changes in the structural features of the confined film. That includes even-odd switching of the structural layering and charging-induced solidification and melting, with important changes of local ordering between and within layers, and of squeezout behavior. By means of molecular dynamics simulations, we explore this variety of phenomena in the simplest charged Lennard-Jones coarse-grained model including or excluding the effect a neutral tail giving an anisotropic shape to one of the model ions. Using these models and open conditions permitting the flow of ions in and out of the interplate gap, we simulate the liquid squeezout to obtain the distance dependent structure and forces between the plates during their adiabatic approach under load. Simulations at fixed applied force illustrate an effective electrical pumping of the ionic liquid, from a thick nearly solid film that withstands the interplate pressure for high plate charge to complete squeezout following melting near zero charge. Effective enthalpy curves obtained by integration of interplate forces versus distance show the local minima that correspond to layering and predict the switching between one minimum and another under squeezing and charging.

  11. Contracting cardiomyocytes in hydrophobic room-temperature ionic liquid

    International Nuclear Information System (INIS)

    Highlights: ► Biocompatible room-temperature ionic liquid was applied on beating cardiomyocyte. ► The lifetime of beating cardiomyocytes was depended on anion functional group. ► A longer lifetime was recorded for no functional group on alkyl chain on their anion. ► Amino group on alkyl chain and fluorine in anion induced fatal condition changes. ► We reported liquid electrolyte interface to stimulate cardiomyocytes. -- Abstract: Room-temperature ionic liquids (RTILs) are drawing attention as a new class of nonaqueous solvents to replace organic and aqueous solvents for chemical processes in the liquid phase at room temperature. The RTILs are notable for their characteristics of nonvolatility, extremely low vapor pressure, electric conductivity, and incombustibility. These distinguished properties of RTILs have brought attention to them in applications with biological cells and tissue in vacuum environment for scanning electron microscopy, and in microfluidic devices for micro-total analysis system (micro-TAS). Habitable RTILs could increase capability of nonaqueous micro-TAS for living cells. Some RTILs seemed to have the capability to replace water in biological applications. However, these RTILs had been applied to just supplemental additives for biocompatible test, to fixed cells as a substitute for an aqueous solution, and to simple molecules. None of RTILs in which directly soaks a living cell culture. Therefore, we demonstrated the design of RTILs for a living cell culture and a liquid electrolyte to stimulate contracting cardiomyocytes using the RTILs. We assessed the effect of RTILs on the cardiomyocytes using the beating lifetime to compare the applicability of RTILs for biological applications. Frequent spontaneous contractions of cardiomyocytes were confirmed in amino acid anion RTILs [P8,8,8,8][Leu] and [P8,8,8,8][Ala], phosphoric acid derivatives [P8,8,8,8][MeO(H)PO2], and [P8,8,8,8][C7CO2]. The anion type of RTILs had influence on

  12. Teleportation of Multi-ionic GHZ States and Arbitrary Bipartite Ionic State via Linear Optics

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    We present a scheme for teleportation of multi-ionic GHZ states and arbitrary bipartite ionic state only by single-qubit measurements via linear optical elements. In our scheme, we avoid the difficulty of joint measurement and synchronizing the arrival time of the two scattered photons, which are faced by previous schemes. So our scheme can be realized easily within current experimental technology.

  13. Ionic liquids--an overview.

    Science.gov (United States)

    Jenkins, Harry Donald Brooke

    2011-01-01

    A virtually unprecedented exponential burst of activity resulted following the publication, in 1998, of an article by Michael Freeman (Freemantle, M. Chemical & Engineering News, 1998, March 30, 32), which speculated on the role and contribution that ionic liquids (ILs) might make in the future on the development of clean technology. Up until that time only a handful of researchers were routinely engaged in the study of ILs but frenzied activity followed that continues until the present day. Scientists from all disciplines related to Chemistry have now embarked on studies, including theoreticians who are immersed in the aim of improving the "designer role" so that they can tailor ILs to deliver specified properties. This article, whilst not in any sense attempting to be exhaustive, highlights the main features which characterise ILs, presenting these in a form readily assimilated by newcomers to this area of research. An extensive glossary is featured in this article as well as a chronological list which charts the major areas of development. What follows consists of a number of sections briefly describing the role of lLs as solvents, hypergolic fuels, their use in some electrochemical devices such as solar cells and lithium batteries and their use in polymerisation reactions, followed by a concise summary of some of the other roles that they are capable of playing. The role of empirical, volume-based thermodynamics procedures, as well as large scale computational studies on ILs is also highlighted. These developments which are described are remarkable in that they have been achieved in less than a decade and a half although knowledge of these materials has existed for much longer. PMID:22026149

  14. Stability of foams in silicate melts

    Science.gov (United States)

    Proussevitch, Alexander A.; Sahagian, Dork L.; Kutolin, Vladislav A.

    1993-12-01

    Bubble coalescence and the spontaneous disruption of high-porosity foams in silicate melts are the result of physical expulsion of interpore melt (syneresis) leading to bubble coalescence, and diffusive gas exchange between bubbles. Melt expulsion can be achieved either along films between pairs of bubbles, or along Plateau borders which represent the contacts between 3 or more bubbles. Theoretical evaluation of these mechanisms is confirmed by experimental results, enabling us to quantify the relevant parameters and determine stable bubble size and critical film thickness in a foam as a function of melt viscosity, surface tension, and time. Foam stability is controlled primarily by melt viscosity and time. Melt transport leading to coalescence of bubbles proceeds along inter-bubble films for smaller bubbles, and along Plateau borders for larger bubbles. Thus the average bubble size accelerates with time. In silicate melts, the diffusive gas expulsion out of a region of foam is effective only for water (and even then, only at small length scales), as the diffusion of CO 2 is negligible. The results of our analyses are applicable to studies of vesicularity of lavas, melt degassing, and eruption mechanisms.

  15. Uniaxial Elongational viscosity of bidisperse polystyrene melts

    DEFF Research Database (Denmark)

    Nielsen, Jens Kromann; Rasmussen, Henrik K.; Hassager, Ole

    2006-01-01

    The startup and steady uniaxial elongational viscosity have been measured for three bidisperse polystyrene (PS) melts, consisting of blends of monodisperse PS with molecular weights of 52 kg/mole or 103 kg/mole and 390 kg/mole. The bidisperse melts have a maximum in the steady elongational...

  16. Bubble Formation in Basalt-like Melts

    DEFF Research Database (Denmark)

    Jensen, Martin; Keding, Ralf; Yue, Yuanzheng

    2011-01-01

    The effect of the melting temperature on bubble size and bubble formation in an iron bearing calcium aluminosilicate melt is studied by means of in-depth images acquired by optical microscopy. The bubble size distribution and the total bubble volume are determined by counting the number of bubble...

  17. Disordering and Melting of Aluminum Surfaces

    DEFF Research Database (Denmark)

    Stoltze, Per; Nørskov, Jens Kehlet; Landman, U.

    1988-01-01

    We report on a molecular-dynamics simulation of an Al(110) surface using the effective-medium theory to describe the interatomic interactions. The surface region is found to start melting ≅200 K below the bulk melting temperature with a gradual increase in the thickness of the disordered layer as...

  18. Melt dumping in string stabilized ribbon growth

    Science.gov (United States)

    Sachs, Emanuel M.

    1986-12-09

    A method and apparatus for stabilizing the edge positions of a ribbon drawn from a melt includes the use of wettable strings drawn in parallel up through the melt surface, the ribbon being grown between the strings. A furnace and various features of the crucible used therein permit continuous automatic growth of flat ribbons without close temperature control or the need for visual inspection.

  19. Snow Melting and Freezing on Older Townhouses

    DEFF Research Database (Denmark)

    Nielsen, Anker; Claesson, Johan

    2011-01-01

    The snowy winter of 2009/2010 in Scandinavia prompted many newspaper articles on icicles falling from buildings and the risk this presented for people walking below. The problem starts with snow melting on the roof due to heat loss from the building. Melt water runs down the roof and some of it w...

  20. Summer Melts Immigrant Students' College Plans

    Science.gov (United States)

    Naranjo, Melissa M.; Pang, Valerie Ooka; Alvarado, Jose Luis

    2016-01-01

    Many college-intending students find themselves dealing with the undermatch and summer melt phenomena. Undermatch refers to the situation where academically-successful high-school graduates choose not to go to any college or to go to a local community college not commensurate with their academic achievements. Summer melt describes how students may…

  1. Size-dependent melting of Bi nanoparticles

    Science.gov (United States)

    Olson, E. A.; Efremov, M. Yu.; Zhang, M.; Zhang, Z.; Allen, L. H.

    2005-02-01

    Nanocalorimetry was used to investigate the melting of Bi nanoparticles. The particles were formed by evaporating Bi onto a silicon nitride substrate, which was then heated. The particles self-assemble into truncated spherical particles. Below 5-nm average film thickness, mean particle sizes increased linearly with deposition thickness but increased rapidly for 10-nm-thick films. As expected, small particles were found to exhibit size-dependent melting temperatures less than the bulk melting temperature (e.g., ΔT =67K for a 3-nm radius particle). The measured melting temperatures for particles below ˜7nm in radius, however, were ˜50K above the value predicted by the homogeneous melting model. We discuss this discrepancy in terms of a possible size-dependent crystal structure change and the superheating of the solid phase.

  2. TRANSITION IN THE MELT OF FEP COPOLYMER

    Institute of Scientific and Technical Information of China (English)

    SHI Guanyi; YUE Junshi

    1983-01-01

    The nature of the transition in molten FEP copolymer was examined in relation to the enthalpy change, mechanical damping and melt viscosity. For a pre-heat-treated FEP copolymer sample a small endothermic peak appeared at 309-312 ℃ in DSC trace with enthalpy change 0.03-0.05cal/g. A peak was also detected in damping versus temperature curve at the same temperature range.The rheological property of FEP copolymer melt was similar to that of liquid crystal, but no birefrigence was viewed in the melt. Therefore the transition was explained as the melting of small crystallites which persist in typical copolymer beyond its melting temperature. These crystallites can act as nuclei for crystallization upon cooling.

  3. Shape evolution of a melting nonspherical particle

    Science.gov (United States)

    Kintea, Daniel M.; Hauk, Tobias; Roisman, Ilia V.; Tropea, Cameron

    2015-09-01

    In this study melting of irregular ice crystals was observed in an acoustic levitator. The evolution of the particle shape is captured using a high-speed video system. Several typical phenomena have been discovered: change of the particle shape, appearance of a capillary flow of the melted liquid on the particle surface leading to liquid collection at the particle midsection (where the interface curvature is smallest), and appearance of sharp cusps at the particle tips. No such phenomena can be observed during melting of spherical particles. An approximate theoretical model is developed which accounts for the main physical phenomena associated with melting of an irregular particle. The agreement between the theoretical predictions for the melting time, for the evolution of the particle shape, and the corresponding experimental data is rather good.

  4. Nanotexturing of surfaces to reduce melting point.

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Ernest J.; Zubia, David (University of Texas at El Paso El Paso, TX); Mireles, Jose (Universidad Aut%C3%94onoma de Ciudad Ju%C3%94arez Ciudad Ju%C3%94arez, Mexico); Marquez, Noel (University of Texas at El Paso El Paso, TX); Quinones, Stella (University of Texas at El Paso El Paso, TX)

    2011-11-01

    This investigation examined the use of nano-patterned structures on Silicon-on-Insulator (SOI) material to reduce the bulk material melting point (1414 C). It has been found that sharp-tipped and other similar structures have a propensity to move to the lower energy states of spherical structures and as a result exhibit lower melting points than the bulk material. Such a reduction of the melting point would offer a number of interesting opportunities for bonding in microsystems packaging applications. Nano patterning process capabilities were developed to create the required structures for the investigation. One of the technical challenges of the project was understanding and creating the specialized conditions required to observe the melting and reshaping phenomena. Through systematic experimentation and review of the literature these conditions were determined and used to conduct phase change experiments. Melting temperatures as low as 1030 C were observed.

  5. Volatile diffusion in silicate melts and its effects on melt inclusions

    Directory of Open Access Journals (Sweden)

    P. Scarlato

    2005-06-01

    Full Text Available A compendium of diffusion measurements and their Arrhenius equations for water, carbon dioxide, sulfur, fluorine, and chlorine in silicate melts similar in composition to natural igneous rocks is presented. Water diffusion in silicic melts is well studied and understood, however little data exists for melts of intermediate to basic compositions. The data demonstrate that both the water concentration and the anhydrous melt composition affect the diffusion coefficient of water. Carbon dioxide diffusion appears only weakly dependent, at most, on the volatilefree melt composition and no effect of carbon dioxide concentration has been observed, although few experiments have been performed. Based upon one study, the addition of water to rhyolitic melts increases carbon dioxide diffusion by orders of magnitude to values similar to that of 6 wt% water. Sulfur diffusion in intermediate to silicic melts depends upon the anhydrous melt composition and the water concentration. In water-bearing silicic melts sulfur diffuses 2 to 3 orders of magnitude slower than water. Chlorine diffusion is affected by both water concentration and anhydrous melt composition; its values are typically between those of water and sulfur. Information on fluorine diffusion is rare, but the volatile-free melt composition exerts a strong control on its diffusion. At the present time the diffusion of water, carbon dioxide, sulfur and chlorine can be estimated in silicic melts at magmatic temperatures. The diffusion of water and carbon dioxide in basic to intermediate melts is only known at a limited set of temperatures and compositions. The diffusion data for rhyolitic melts at 800°C together with a standard model for the enrichment of incompatible elements in front of growing crystals demonstrate that rapid crystal growth, greater than 10-10 ms-1, can significantly increase the volatile concentrations at the crystal-melt interface and that any of that melt trapped

  6. Melt Rate Improvement for DWPF MB3: Melt Rate Furnace Testing

    Energy Technology Data Exchange (ETDEWEB)

    Stone, M.E.

    2001-07-24

    The Defense Waste Processing Facility (DWPF) would like to increase its canister production rate. The goal of this study is to improve the melt rate in DWPF specifically for Macrobatch 3. However, the knowledge gained may result in improved melting efficiencies translating to future DWPF macrobatches and in higher throughput for other Department of Energy's (DOE) melters. Increased melting efficiencies decrease overall operational costs by reducing the immobilization campaign time for a particular waste stream. For melt rate limited systems, a small increase in melting efficiency translates into significant hard dollar savings by reducing life cycle operational costs.

  7. The laws governing ionic liquid extraction of cations: partition of 1-ethylpyridinium monocation and paraquat dication in ionic liquid/water biphasic systems.

    Science.gov (United States)

    Hamamoto, Takuya; Okai, Miho; Katsuta, Shoichi

    2015-05-21

    To find the laws governing the extraction of cations from aqueous solutions into hydrophobic ionic liquids (ILs), we investigated the partition of 1-ethylpyridinium monocation and paraquat (1,1'-dimethyl-4,4'-bipyridinium) dication in various IL/water biphasic systems. Ten different ILs of 1-butyl-3-methylimidazolium-based or bis(trifluoromethanesulfonyl)amide-based salts were used. The distribution ratio of the target cations (T(n+)) was dependent on the initial concentration in the aqueous phase and also very sensitive to the kind of IL. The behavior was quantitatively explained on the basis of a model in which the extraction goes through both the ion exchange and ion pair transfer processes, while keeping the product of the aqueous concentrations of the IL constituent ions a constant value (solubility product, Ksp). The distribution ratio of T(n+) is expressed as a function of the difference between the initial and equilibrium concentrations of T(n+) in the aqueous phase (Δ[T(n+)]W), the aqueous solubility of IL (Ksp(1/2)), and the cation valence n. The distribution ratio is a nearly constant value (D0) when Δ[T(n+)]W ≪ Ksp(1/2)/n and decreases inversely proportional to the nth power of Δ[T(n+)]W when Δ[T(n+)]W ≫ Ksp(1/2)/n. The log D0 versus log Ksp(1/2) plot gives a linear relationship with a slope of +n for the ILs with the same anion but different cations and that with a slope of nearly -n for the ILs with the same cation but different anions. This means that the extractability dependence on the kinds of IL constituent ions is greater for the divalent cation than for the monovalent one.

  8. Deposition of metal films on an ionic liquid as a basis for a lunar telescope

    Science.gov (United States)

    Borra, Ermanno F.; Seddiki, Omar; Angel, Roger; Eisenstein, Daniel; Hickson, Paul; Seddon, Kenneth R.; Worden, Simon P.

    2007-06-01

    An optical/infrared telescope of 20-100m aperture located on the Moon would be able to observe objects 100 to 1,000 times fainter than the proposed next generation of space telescopes. The infrared region of the spectrum is particularly important for observations of objects at redshifts z>7. The apparent simplicity and low mass of a liquid mirror telescope, compared with a traditional pointable glass mirror, suggest that the concept should be considered further. A previously proposed liquid mirror telescope, based upon a spinning liquid metallic alloy, is not appropriate for infrared applications, which will require a liquid below 130K. Here we report the successful coating of an ionic liquid with silver. The surface is smooth and the silver coating is stable on a timescale of months. The underlying ionic liquid does not evaporate in a vacuum and remains liquid down to a temperature of 175K. Given that there are ~106 simple and ~1018 ternary ionic liquids, it should be possible to synthesize liquids with even lower melting temperatures.

  9. Understanding the hydrogen bonds in ionic liquids and their roles in properties and reactions.

    Science.gov (United States)

    Dong, Kun; Zhang, Suojiang; Wang, Jianji

    2016-05-21

    Ionic liquids (ILs) have many potential applications in the chemical industry. In order to understand ILs, their molecular details have been extensively investigated. Intuitively, electrostatic forces are solely important in ILs. However, experiments and calculations have provided strong evidence for the existence of H-bonds in ILs and their roles in the properties and applications of ILs. As a structure-directing force, H-bonds are responsible for ionic pairing, stacking and self-assembling. Their geometric structure, interaction energy and electronic configuration in the ion-pairs of imidazolium-based ILs and protic ionic liquids (PILs) show a great number of differences compared to conventional H-bonds. In particular, their cooperation with electrostatic, dispersion and π interactions embodies the physical nature of H-bonds in ILs, which anomalously influences their properties, leading to a decrease in their melting points and viscosities and thus fluidizing them. Using ILs as catalysts and solvents, many reactions can be activated by the presence of H-bonds, which reduce the reaction barriers and stabilize the transition states. In the dissolution of lignocellulosic biomass by ILs, H-bonds exhibit a most important role in disrupting the H-bonding network of cellulose and controlling microscopic ordering into domains. In this article, a critical review is presented regarding the structural features of H-bonds in ILs and PILs, the correlation between H-bonds and the properties of ILs, and the roles of H-bonds in typical reactions. PMID:27042709

  10. (1-Butyl-4-methyl-pyridinium)[Cu(SCN)2]: a coordination polymer and ionic liquid.

    Science.gov (United States)

    Spielberg, Eike T; Edengeiser, Eugen; Mallick, Bert; Havenith, Martina; Mudring, Anja-Verena

    2014-04-25

    The compound (C4C1py)[Cu(SCN)2], (C4C1py = 1-Butyl-4-methyl-pyridinium), which can be obtained from CuSCN and the ionic liquid (C4C1py)(SCN), turns out to be a new organic-inorganic hybrid material as it qualifies both, as a coordination polymer and an ionic liquid. It features linked [Cu(SCN)2](-) units, in which the thiocyanates bridge the copper ions in a μ1,3-fashion. The resulting one-dimensional chains run along the a axis, separated by the C4C1py counterions. Powder X-ray diffraction not only confirms the single-crystal X-ray structure solution but proves the reformation of the coordination polymer from an isotropic melt. However, the materials shows a complex thermal behavior often encountered for ionic liquids such as a strong tendency to form a supercooled melt. At a relatively high cooling rate, glass formation is observed. When heating this melt in differential scanning calorimetry (DSC) and temperature-dependent polarizing optical microscopy (POM), investigations reveal the existence of a less thermodynamically stable crystalline polymorph. Raman measurements conducted at 10 and 100 °C point towards the formation of polyanionic chain fragments in the melt. Solid-state UV/Vis spectroscopy shows a broad absorption band around 18,870 cm(-1) (530 nm) and another strong one below 20,000 cm(-1) (<500 nm). The latter is attributed to the d(Cu(I))→π*(SCN)-MLCT (metal-to-ligand charge transfer) transition within the coordination polymer yielding an energy gap of 2.4 eV. At room temperature and upon irradiation with UV light, the material shows a weak fluorescence band at 15,870 cm(-1) (630 nm) with a quantum efficiency of 0.90(2) % and a lifetime of 131(2) ns. Upon lowering the temperature, the luminescence intensity strongly increases. Simultaneously, the band around 450 nm in the excitation spectrum decreases. PMID:24644064

  11. Modulating enzyme activity using ionic liquids or surfactants.

    Science.gov (United States)

    Goldfeder, Mor; Fishman, Ayelet

    2014-01-01

    One of the important strategies for modulating enzyme activity is the use of additives to affect their microenvironment and subsequently make them suitable for use in different industrial processes. Ionic liquids (ILs) have been investigated extensively in recent years as such additives. They are a class of solvents with peculiar properties and a "green" reputation in comparison to classical organic solvents. ILs as co-solvents in aqueous systems have an effect on substrate solubility, enzyme structure and on enzyme-water interactions. These effects can lead to higher reaction yields, improved selectivity, and changes in substrate specificity, and thus there is great potential for IL incorporation in biocatalysis. The use of surfactants, which are usually denaturating agents, as additives in enzymatic reactions is less reviewed in recent years. However, interesting modulations in enzyme activity in their presence have been reported. In the case of surfactants there is a more pronounced effect on the enzyme structure, as can be observed in a number of crystal structures obtained in their presence. For each additive and enzymatic process, a specific optimization process is needed and there is no one-fits-all solution. Combining ILs and surfactants in either mixed micelles or water-in-IL microemulsions for use in enzymatic reaction systems is a promising direction which may further expand the range of enzyme applications in industrial processes. While many reviews exist on the use of ILs in biocatalysis, the present review centers on systems in which ILs or surfactants were able to modulate and improve the natural activity of enzymes in aqueous systems. PMID:24281758

  12. Water Contaminant Mitigation in Ionic Liquid Propellant

    Science.gov (United States)

    Conroy, David; Ziemer, John

    2009-01-01

    Appropriate system and operational requirements are needed in order to ensure mission success without unnecessary cost. Purity requirements applied to thruster propellants may flow down to materials and operations as well as the propellant preparation itself. Colloid electrospray thrusters function by applying a large potential to a room temperature liquid propellant (such as an ionic liquid), inducing formation of a Taylor cone. Ions and droplets are ejected from the Taylor cone and accelerated through a strong electric field. Electrospray thrusters are highly efficient, precise, scaleable, and demonstrate low thrust noise. Ionic liquid propellants have excellent properties for use as electrospray propellants, but can be hampered by impurities, owing to their solvent capabilities. Of foremost concern is the water content, which can result from exposure to atmosphere. Even hydrophobic ionic liquids have been shown to absorb water from the air. In order to mitigate the risks of bubble formation in feed systems caused by water content of the ionic liquid propellant, physical properties of the ionic liquid EMI-Im are analyzed. The effects of surface tension, material wetting, physisorption, and geometric details of the flow manifold and electrospray emitters are explored. Results are compared to laboratory test data.

  13. Terrestrial impact melt rocks and glasses

    Science.gov (United States)

    Dressler, B. O.; Reimold, W. U.

    2001-12-01

    The effects of meteorite and comet impact on Earth are rock brecciation, the formation of shock metamorphic features, rock melting, and the formation of impact structures, i.e. simple craters, complex craters, and multi-ring basins. Large events, such as the 65-Ma Chicxulub impact, are believed to have had catastrophic environmental effects that profoundly influenced the development of life on Earth. In this review, an attempt is made to summarize some of the voluminous literature on impact melting, one important aspect of planetary impact, provide some comments on this process, and to make suggestions for future research. The products of impact melting are glasses, impact melt rocks, and pseudotachylites. Our treatise deals mainly with the geological setting, petrography, and major-element chemistry of melt rocks and glasses. Impact glasses, in several petrographic aspects, are similar to volcanic glasses, but they are associated with shock metamorphosed mineral and rock fragments and, in places, with siderophile element anomalies suggestive of meteoritic contamination. They are found in allogenic breccia deposits within (fall-back 'suevite') and outside (fall-out 'suevite') impact craters and, as spherules, in distal ejecta. Large events, such as the K/T boundary Chicxulub impact, are responsible for the formation of worldwide ejecta horizons which are associated with siderophile element anomalies and shock metamorphosed mineral and rock debris. Impact glasses have a bulk chemical composition that is homogeneous but exemptions to this rule are common. On a microscopic scale, however, impact glasses are commonly strikingly heterogeneous. Tektites are glasses ejected from craters over large distances. They are characterized by very low water and volatile contents and element abundances and ratios that are evidence that tektites formed by melting of upper crustal, sedimentary rocks. Four tektite strewn-fields are known, three of which can be tied to specific impact

  14. The Research Progress of CO2 Capture with Ionic Liquids

    Institute of Scientific and Technical Information of China (English)

    赵志军; 董海峰; 张香平

    2012-01-01

    Due to their negligible volatility, reasonable thermal stability, strong dissolubility, wide liquid range and tunability of structure and property, ionic liquids have been regarded as emerging candidate reagents for CO2 cap- ture from industries gases. In this review, the research progresses in CO2 capture using conventional ionic liquids,functionalized ionic liquids, supported ionic-liquids membranes, polymerized ionic liquids and mixtures of ionic liquids with some molecular solvents were investigated and reviewed. Discussion of relevant research fields was presented and the future developments were suggested.

  15. Excluded volume and ion-ion correlation effects on the ionic atmosphere around B-DNA: Theory, simulations, and experiments

    Energy Technology Data Exchange (ETDEWEB)

    Ovanesyan, Zaven; Marucho, Marcelo, E-mail: marcelo.marucho@utsa.edu [Department of Physics and Astronomy, The University of Texas at San Antonio, San Antonio, Texas 78249-5003 (United States); Medasani, Bharat [Department of Physics and Astronomy, The University of Texas at San Antonio, San Antonio, Texas 78249-5003 (United States); Computational Research Division, Lawrence Berkeley National Lab, Berkeley, California 94700 (United States); Fenley, Marcia O. [Institute of Molecular Biophysics, Florida State University, Tallahassee, Florida 32306 (United States); Guerrero-García, Guillermo Iván [Instituto de Física, Universidad Autónoma de San Luis Potosí, Álvaro Obregón 64, 78000 San Luis Potosí, San Luis Potosí (Mexico); Department of Chemistry and Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (United States); Olvera de la Cruz, Mónica [Department of Chemistry and Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (United States)

    2014-12-14

    The ionic atmosphere around a nucleic acid regulates its stability in aqueous salt solutions. One major source of complexity in biological activities involving nucleic acids arises from the strong influence of the surrounding ions and water molecules on their structural and thermodynamic properties. Here, we implement a classical density functional theory for cylindrical polyelectrolytes embedded in aqueous electrolytes containing explicit (neutral hard sphere) water molecules at experimental solvent concentrations. Our approach allows us to include ion correlations as well as solvent and ion excluded volume effects for studying the structural and thermodynamic properties of highly charged cylindrical polyelectrolytes. Several models of size and charge asymmetric mixtures of aqueous electrolytes at physiological concentrations are studied. Our results are in good agreement with Monte Carlo simulations. Our numerical calculations display significant differences in the ion density profiles for the different aqueous electrolyte models studied. However, similar results regarding the excess number of ions adsorbed to the B-DNA molecule are predicted by our theoretical approach for different aqueous electrolyte models. These findings suggest that ion counting experimental data should not be used alone to validate the performance of aqueous DNA-electrolyte models.

  16. Excluded volume and ion-ion correlation effects on the ionic atmosphere around B-DNA: Theory, simulations, and experiments

    International Nuclear Information System (INIS)

    The ionic atmosphere around a nucleic acid regulates its stability in aqueous salt solutions. One major source of complexity in biological activities involving nucleic acids arises from the strong influence of the surrounding ions and water molecules on their structural and thermodynamic properties. Here, we implement a classical density functional theory for cylindrical polyelectrolytes embedded in aqueous electrolytes containing explicit (neutral hard sphere) water molecules at experimental solvent concentrations. Our approach allows us to include ion correlations as well as solvent and ion excluded volume effects for studying the structural and thermodynamic properties of highly charged cylindrical polyelectrolytes. Several models of size and charge asymmetric mixtures of aqueous electrolytes at physiological concentrations are studied. Our results are in good agreement with Monte Carlo simulations. Our numerical calculations display significant differences in the ion density profiles for the different aqueous electrolyte models studied. However, similar results regarding the excess number of ions adsorbed to the B-DNA molecule are predicted by our theoretical approach for different aqueous electrolyte models. These findings suggest that ion counting experimental data should not be used alone to validate the performance of aqueous DNA-electrolyte models

  17. Melt and Chemical Transport in the Mantle: Insights from Deglaciation-Induced Melting Perturbations in Iceland

    Science.gov (United States)

    Eason, D. E.; Ito, G.; Sinton, J. M.

    2011-12-01

    Eruptive products represent a time-averaged view of the melting region and melt migration processes, making numerous fundamental parameters of the melt system difficult to constrain. Temporal and spatial variations in melting provide potential windows into this obscure region of the Earth by preferentially sampling melts from different regions of the mantle or mixing melts over different length-scales. We present a newly extended geochemical time series from the Western Volcanic Zone (WVZ) of Iceland, which experienced a short-lived melting perturbation due to glacial unloading during the last major deglaciation (~15-10 ka). Glacial unloading during this period led to increased degrees of melting particularly in the shallow mantle, which is manifest as an observed increase in volcanic production up to 30 times the steady-state value, decreased levels of highly to moderately incompatible element ratios (e.g., a 35-50% decrease in Nb/Y, with the greatest change occurring in the northernmost WVZ), and elevated SiO2 and CaO concentrations (~0.8 wt. % and ~1.9 wt. % increase in average oxide concentrations respectively) during and immediately following deglaciation. Although eruptive productivity returns to steady-state values within ~3000 yr following deglaciation, the incompatible element concentrations in erupted lavas gradually increase throughout the post-glacial period. We exploit this short-lived melting perturbation to examine and constrain knowledge of fundamental characteristics of melt generation and transport, including mantle permeability, melt ascent rates, depth-dependent melting functions (dF/dP), and the nature of chemical transport and melt mixing in the system. Using conservation equations describing the generation and porous flow of melt in a viscous matrix, we model melt migration in the mantle during and after ice sheet removal, as well as trace element transport for both equilibrium and disequilibrium transport end members. The predicted

  18. Evaluation of Melt Behavior with initial Melt Velocity under SFR Severe Accidents

    Energy Technology Data Exchange (ETDEWEB)

    Heo, Hyo; Bang, In Cheol [UNIST, Ulsan (Korea, Republic of); Jerng, Dong Wook [Chung-Ang Univ, Seoul (Korea, Republic of)

    2015-10-15

    In the current Korean sodium-cooled fast reactor (SFR) program, early dispersion of the molten metallic fuel within a subchannel is suggested as one of the inherent safety strategies for the initiating phase of hypothetical core disruptive accident (HCDA). The safety strategy provides negative reactivity driven by the melt dispersal, so it could reduce the possibility of the recriticality event under a severe triple or more fault scenario for SFR. Since the behavior of the melt dispersion is unpredictable, it depends on the accident condition, particularly core region. While the voided coolant channel region is usually developed in the inner core, the unvoided coolant channel region is formed in the outer core. It is important to confirm the fuel dispersion with the core region, but there are not sufficient existing studies for them. From the existing studies, the coolant vapor pressure is considered as one of driving force to move the melt towards outside of the core. There is a complexity of the phenomena during intermixing of the melt with the coolant after the horizontal melt injections. It is too difficult to understand the several combined mechanisms related to the melt dispersion and the fragmentation. Thus, it could be worthwhile to study the horizontal melt injections at lower temperature as a preliminary study in order to identify the melt dispersion phenomena. For this reason, it is required to clarify whether the coolant vapor pressure is the driving force of the melt dispersion with the core region. The specific conditions to be well dispersed for the molten metallic fuel were discussed in the experiments with the simulant materials. The each melt behavior was compared to evaluate the melt dispersion under the coolant void condition and the boiling condition. As the results, the following results are remarked: 1. The upward melt dispersion did not occur for a given melt and coolant temperature in the nonboiling range. Over current range of conditions

  19. Viscosity of ring polymer melts

    KAUST Repository

    Pasquino, Rossana

    2013-10-15

    We have measured the linear rheology of critically purified ring polyisoprenes, polystyrenes, and polyethyleneoxides of different molar masses. The ratio of the zero-shear viscosities of linear polymer melts η0,linear to their ring counterparts η0,ring at isofrictional conditions is discussed as a function of the number of entanglements Z. In the unentangled regime η0,linear/η 0,ring is virtually constant, consistent with the earlier data, atomistic simulations, and the theoretical expectation η0,linear/ η0,ring = 2. In the entanglement regime, the Z-dependence of ring viscosity is much weaker than that of linear polymers, in qualitative agreement with predictions from scaling theory and simulations. The power-law extracted from the available experimental data in the rather limited range 1 < Z < 20, η0,linear/η0,ring ∼ Z 1.2±0.3, is weaker than the scaling prediction (η0,linear/η0,ring ∼ Z 1.6±0.3) and the simulations (η0,linear/ η0,ring ∼ Z2.0±0.3). Nevertheless, the present collection of state-of-the-art experimental data unambiguously demonstrates that rings exhibit a universal trend clearly departing from that of their linear counterparts, and hence it represents a major step toward resolving a 30-year-old problem. © 2013 American Chemical Society.

  20. Olivine flotation in mantle melt

    Science.gov (United States)

    Agee, Carl B.; Walker, David

    1993-01-01

    Molten komatiite and peridotite have been compressed in an octahedral multi-anvil device up to 10 GPa. Densities of the melts were measured at pressure intervals in the range 7 to 10 GPa by observing sinking and floating San Carlos olivines and synthetic forsterite marker spheres. The multi-anvil results for komatiite, when combined with piston-cylinder measurements done at 4 to 6 GPa and a calculated reference density at 10 5 Pa, yield a Birch-Murnaghan isothermal bulk modulus of (K 1900C) = 26 GPa and pressure derivative K' = 4.25. The pressure of neutral buoyancy for olivine in komatiite is confirmed to be near 8 GPa as predicted in earlier work. Olivine flotation in the experimental komatiite commences at a pressure close to where the liquidus phase changes from olivine to denser garnet, leading to the possibility of density driven crystal sorting during fractionation. Molten peridotite (KLB-1) shows an isothermal compression (2000°C) of 0.065 g cm -3 GPa -1 in the interval 10 5 Pa to 8.2 GPa. The olivine/liquid peridotite density crossover is predicted to lie between 9 and 11 GPa, indicating that olivine flotation can operate at depths of 300-500 km in a molten peridotitic mantle.

  1. Characterization of aqueous silver nitrate solutions for leakage tests

    Directory of Open Access Journals (Sweden)

    José Ferreira Costa

    2011-06-01

    Full Text Available OBJECTIVE: To determine the pH over a period of 168 h and the ionic silver content in various concentrations and post-preparation times of aqueous silver nitrate solutions. Also, the possible effects of these factors on microleakage test in adhesive/resin restorations in primary and permanent teeth were evaluated. MATERIAL AND METHODS: A digital pHmeter was used for measuring the pH of the solutions prepared with three types of water (purified, deionized or distilled and three brands of silver nitrate salt (Merck, Synth or Cennabras at 0, 1, 2, 24, 48, 72, 96 and 168 h after preparation, and storage in transparent or dark bottles. Ionic silver was assayed according to the post-preparation times (2, 24, 48, 72, 96, 168 h and concentrations (1, 5, 25, 50% of solutions by atomic emission spectrometry. For each sample of each condition, three readings were obtained for calculating the mean value. Class V cavities were prepared with enamel margins on primary and permanent teeth and restored with the adhesive systems OptiBond FL or OptiBond SOLO Plus SE and the composite resin Filtek Z-250. After nail polish coverage, the permanent teeth were immersed in 25% or 50% AgNO3 solution and the primary teeth in 5% or 50% AgNO3 solutions for microleakage evaluation. ANOVA and the Tukey's test were used for data analyses (α=5%. RESULTS: The mean pH of the solutions ranged from neutral to alkaline (7.9±2.2 to 11.8±0.9. Mean ionic silver content differed depending on the concentration of the solution (4.75±0.5 to 293±15.3 ppm. In the microleakage test, significant difference was only observed for the adhesive system factor (p=0.000. CONCLUSIONS: Under the tested experimental conditions and based on the obtained results, it may be concluded that the aqueous AgNO3 solutions: have neutral/alkaline pH and service life of up to 168 h; the level of ionic silver is proportional to the concentration of the solution; even at 5% concentration, the solutions were

  2. Characterization of aqueous silver nitrate solutions for leakage tests

    Science.gov (United States)

    COSTA, José Ferreira; SIQUEIRA, Walter Luiz; LOGUERCIO, Alessandro Dourado; REIS, Alessandra; de OLIVEIRA, Elizabeth; ALVES, Cláudia Maria Coelho; BAUER, José Roberto de Oliveira; GRANDE, Rosa Helena Miranda

    2011-01-01

    Objectives To determine the pH over a period of 168 h and the ionic silver content in various concentrations and post-preparation times of aqueous silver nitrate solutions. Also, the possible effects of these factors on microleakage test in adhesive/resin restorations in primary and permanent teeth were evaluated. Material and Methods A digital pHmeter was used for measuring the pH of the solutions prepared with three types of water (purified, deionized or distilled) and three brands of silver nitrate salt (Merck, Synth or Cennabras) at 0, 1, 2, 24, 48, 72, 96 and 168 h after preparation, and storage in transparent or dark bottles. Ionic silver was assayed according to the post-preparation times (2, 24, 48, 72, 96, 168 h) and concentrations (1, 5, 25, 50%) of solutions by atomic emission spectrometry. For each sample of each condition, three readings were obtained for calculating the mean value. Class V cavities were prepared with enamel margins on primary and permanent teeth and restored with the adhesive systems OptiBond FL or OptiBond SOLO Plus SE and the composite resin Filtek Z-250. After nail polish coverage, the permanent teeth were immersed in 25% or 50% AgNO3 solution and the primary teeth in 5% or 50% AgNO3 solutions for microleakage evaluation. ANOVA and the Tukey's test were used for data analyses (α=5%). Results The mean pH of the solutions ranged from neutral to alkaline (7.9±2.2 to 11.8±0.9). Mean ionic silver content differed depending on the concentration of the solution (4.75±0.5 to 293±15.3 ppm). In the microleakage test, significant difference was only observed for the adhesive system factor (p=0.000). Conclusions Under the tested experimental conditions and based on the obtained results, it may be concluded that the aqueous AgNO3 solutions: have neutral/alkaline pH and service life of up to 168 h; the level of ionic silver is proportional to the concentration of the solution; even at 5% concentration, the solutions were capable of

  3. Stability and aggregation of metal oxide nanoparticles in natural aqueous matrices.

    Science.gov (United States)

    Keller, Arturo A; Wang, Hongtao; Zhou, Dongxu; Lenihan, Hunter S; Cherr, Gary; Cardinale, Bradley J; Miller, Robert; Ji, Zhaoxia

    2010-03-15

    There is a pressing need for information on the mobility of nanoparticles in the complex aqueous matrices found in realistic environmental conditions. We dispersed three different metal oxide nanoparticles (TiO(2), ZnO and CeO(2)) in samples taken from eight different aqueous media associated with seawater, lagoon, river, and groundwater, and measured their electrophoretic mobility, state of aggregation, and rate of sedimentation. The electrophoretic mobility of the particles in a given aqueous media was dominated by the presence of natural organic matter (NOM) and ionic strength, and independent of pH. NOM adsorbed onto these nanoparticles significantly reduces their aggregation, stabilizing them under many conditions. The transition from reaction to diffusion limited aggregation occurs at an electrophoretic mobility from around -2 to -0.8 microm s(-1) V(-1) cm. These results are key for designing and interpreting nanoparticle ecotoxicity studies in various environmental conditions. PMID:20151631

  4. The stability of poly(2,2′-(m-phenylene)-5,5′-bibenzimidazole) membranes in aqueous potassium hydroxide

    DEFF Research Database (Denmark)

    Aili, David; Jankova Atanasova, Katja; Li, Qingfeng;

    2015-01-01

    In the form of membranes, poly(2,2′-(m-phenylene)-5,5′-bibenzimidazole) (mPBI) is known to exhibit high ionic conductivity when doped with aqueous KOH, which makes it interesting as electrolyte in e.g. alkaline fuel cells and water electrolyzers. The conductivity peaks at KOH concentrations aroun...

  5. Static dielectric properties of dense ionic fluids.

    Science.gov (United States)

    Zarubin, Grigory; Bier, Markus

    2015-05-14

    The static dielectric properties of dense ionic fluids, e.g., room temperature ionic liquids (RTILs) and inorganic fused salts, are investigated on different length scales by means of grandcanonical Monte Carlo simulations. A generally applicable scheme is developed which allows one to approximately decompose the electric susceptibility of dense ionic fluids into the orientation and the distortion polarization contribution. It is shown that at long range, the well-known plasma-like perfect screening behavior occurs, which corresponds to a diverging distortion susceptibility, whereas at short range, orientation polarization dominates, which coincides with that of a dipolar fluid of attached cation-anion pairs. This observation suggests that the recently debated interpretation of RTILs as dilute electrolyte solutions might not be simply a yes-no-question but it might depend on the considered length scale. PMID:25978895

  6. Individual SWCNT based ionic field effect transistor

    Science.gov (United States)

    Pang, Pei; He, Jin; Park, Jae Hyun; Krstic, Predrag; Lindsay, Stuart

    2011-03-01

    Here we report that the ionic current through a single-walled carbon nanotube (SWCNT) can be effectively gated by a perpendicular electrical field from a top gate electrode, working as ionic field effect transistor. Both our experiment and simulation confirms that the electroosmotic current (EOF) is the main component in the ionic current through the SWCNT and is responsible for the gating effect. We also studied the gating efficiency as a function of solution concentration and pH and demonstrated that the device can work effectively in the physiological relevant condition. This work opens the door to use CNT based nanofluidics for ion and molecule manipulation. This work was supported by the DNA Sequencing Technology Program of the National Human Genome Research Institute (1RC2HG005625-01, 1R21HG004770-01), Arizona Technology Enterprises and the Biodesign Institute.

  7. Enzyme activity in dialkyl phosphate ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, M.F.; Dunn, J.; Li, L.-L.; Handley-Pendleton, J. M.; van der lelie, D.; Wishart, J. F.

    2011-12-01

    The activity of four metagenomic enzymes and an enzyme cloned from the straw mushroom, Volvariellavolvacea were studied in the following ionic liquids, 1,3-dimethylimidazolium dimethyl phosphate, [mmim][dmp], 1-ethyl-3-methylimidazolium dimethyl phosphate, [emim][dmp], 1-ethyl-3-methylimidazolium diethyl phosphate, [emim][dep] and 1-ethyl-3-methylimidazolium acetate, [emim][OAc]. Activity was determined by analyzing the hydrolysis of para-nitrobenzene carbohydrate derivatives. In general, the enzymes were most active in the dimethyl phosphate ionic liquids, followed by acetate. Generally speaking, activity decreased sharply for concentrations of [emim][dep] above 10% v/v, while the other ionic liquids showed less impact on activity up to 20% v/v.

  8. BWR radiation buildup control with ionic zinc

    International Nuclear Information System (INIS)

    In 1983 a hypothesis was disclosed which suggested that the presence of ionic zinc in the reactor water of the BWR could reduce radiation buildup. This hypothesis was developed from correlations of plant data, and subsequently, from laboratory experiments which demonstrated clearly that ionic zinc inhibits the corrosion of stainless steel. The benefits of zinc addition have been measured at the Vallecitos Nuclear Center under and EPRI/GE project. Experimentation and analyses have been performed to evaluate the impact of intentional zinc addition on the IGSCC characteristics of primary system materials and on the performance of the nuclear fuel. It has been concluded that no negative effects are expected. The author conclude that the intentional addition of ionic zinc to the BWR reactor water at a concentration of approximately 10 ppb will provide major benefits in controlling the Co-60 buildup on primary system stainless steel surfaces. The intentional addition of zinc is now a qualified technique for use in BWRs

  9. Thermally controlled permeation of ionic molecules through synthetic nanopores functionalized with amine-terminated polymer brushes

    Science.gov (United States)

    Nasir, Saima; Ali, Mubarak; Ensinger, Wolfgang

    2012-06-01

    We present temperature-dependent ionic transport through an array of nanopores (cylindrical and conical) and a single conical nanopore functionalized with amine-terminated poly(N-isopropylacrylamide) [PNIPAAM-NH2] brushes. For this purpose, nanopores are fabricated in heavy ion irradiated polyethylene terephthlate (PET) membranes by a controlled chemical track-etching technique, which leads to the generation of carboxyl (COOH) groups on the pore surface. End-functionalized polymer chains are immobilized onto the inner pore walls via a ‘grafting-to’ approach through the covalent linkage of surface COOH moieties with the terminal amine groups of the PNIPAAM molecules by using carbodiimide coupling chemistry. The success of the chemical modification reaction is corroborated by measuring the permeation flux of charged analytes across the multipore membranes in an aqueous solution, and for the case of single conical pore by measuring the current-voltage (I-V) characteristics, which are dictated by the electrostatic interaction of the charged pore surface with the mobile ions in an electrolyte solution. The effective nanopore diameter is tuned by manipulating the environmental temperature due to the swelling/shrinking behaviour of polymer brushes attached to the inner nanopore walls, leading to a decrease/increase in the ionic transport across the membrane. This process should permit the thermal gating and controlled release of ionic drug molecules through the nanopores modified with thermoresponsive polymer chains across the membrane.

  10. Thermally controlled permeation of ionic molecules through synthetic nanopores functionalized with amine-terminated polymer brushes

    International Nuclear Information System (INIS)

    We present temperature-dependent ionic transport through an array of nanopores (cylindrical and conical) and a single conical nanopore functionalized with amine-terminated poly(N-isopropylacrylamide) [PNIPAAM-NH2] brushes. For this purpose, nanopores are fabricated in heavy ion irradiated polyethylene terephthlate (PET) membranes by a controlled chemical track-etching technique, which leads to the generation of carboxyl (COOH) groups on the pore surface. End-functionalized polymer chains are immobilized onto the inner pore walls via a ‘grafting-to’ approach through the covalent linkage of surface COOH moieties with the terminal amine groups of the PNIPAAM molecules by using carbodiimide coupling chemistry. The success of the chemical modification reaction is corroborated by measuring the permeation flux of charged analytes across the multipore membranes in an aqueous solution, and for the case of single conical pore by measuring the current–voltage (I–V) characteristics, which are dictated by the electrostatic interaction of the charged pore surface with the mobile ions in an electrolyte solution. The effective nanopore diameter is tuned by manipulating the environmental temperature due to the swelling/shrinking behaviour of polymer brushes attached to the inner nanopore walls, leading to a decrease/increase in the ionic transport across the membrane. This process should permit the thermal gating and controlled release of ionic drug molecules through the nanopores modified with thermoresponsive polymer chains across the membrane. (paper)

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

    Science.gov (United States)

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

    2011-06-01

    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. PMID:21547960

  12. Synthesis of magnetic graphene nanocomposites decorated with ionic liquids for fast lead ion removal.

    Science.gov (United States)

    Sun, Weiyan; Li, Leilei; Luo, Chuannan; Fan, Lulu

    2016-04-01

    Seeking highly-efficient, low-cost and robust methods to remove metal ions from aqueous solutions is very much in demand. Here, we developed a novel magnetic composite bio-adsorbent, graphene oxide and magnetic chitosan-ionic liquids (GOMCS-ILs), for removing Pb(II) from water. This was the first time to combine ionic liquids and graphene oxide and magnetic chitosan, and apply to the adsorption of metal ions. The addition of ionic liquids can not only improve the dispersivity of the adsorbent, but also increase the adsorption sites. The characteristic result of FTIR, SEM, and XRD showed that GOMCS-ILs were prepared with large surface area and good magnetic responsiveness. The influence of various analytical parameters on the adsorption of Pb(II) such as pH, contact time, and initial ion concentration were studied in detail. The adsorption followed a pseudo second order kinetics. The equilibrium adsorption was well-described by the Langmuir isotherm model and the maximum adsorption capacity was to be 85mgg(-1). Moreover, the GOMCS-ILs could be repeatedly used by simple treatment without obvious structure and performance degradation. These results demonstrated the potential applications of GOMCS-ILs microspheres in efficient removal of Pb(II) from wastewater and deep-purification of polluted water.

  13. Polypyrrole for Artificial Muscles: Ionic Mechanisms

    DEFF Research Database (Denmark)

    Skaarup, Steen

    2006-01-01

    ), opening the possibility of making control and measurement both safe and accurate. The actuation process is identical to charging and discharging an electrochemical cell during redox cycling of a rechargeable battery. It involves ions moving between the electrolyte and being inserted in, or expelled from....... This work examines the influence of solvent, ionic species and electrolyte concentration on the fundamental question about the ionic mechanism involved: Is the actuation process driven by anion motion, cation motion, or a mixture of the two? In addition: What is the extent of solvent motion? The discussion...

  14. Ionic solutes impact collagen scaffold bioactivity.

    Science.gov (United States)

    Pawelec, K M; Husmann, A; Wardale, R J; Best, S M; Cameron, R E

    2015-02-01

    The structure of ice-templated collagen scaffolds is sensitive to many factors. By adding 0.5 wt% of sodium chloride or sucrose to collagen slurries, scaffold structure could be tuned through changes in ice growth kinetics and interactions of the solute and collagen. With ionic solutes (sodium chloride) the entanglements of the collagen molecule decreased, leading to fibrous scaffolds with increased pore size and decreased attachment of chondrocytes. With non-ionic solutes (sucrose) ice growth was slowed, leading to significantly reduced pore size and up-regulated cell attachment. This highlights the large changes in structure and biological function stimulated by solutes in ice-templating systems. PMID:25649518

  15. Anodic dissolution of metals in ionic liquids

    OpenAIRE

    Abbott, Andrew P.; Gero Frisch; Jennifer Hartley; Wrya O. Karim; Ryder, Karl S.

    2015-01-01

    The anodic dissolution of metals is an important topic for battery design, material finishing and metal digestion. Ionic liquids are being used in all of these areas but the research on the anodic dissolution is relatively few in these media. This study investigates the behaviour of 9 metals in an ionic liquid [C4mim][Cl] and a deep eutectic solvent, Ethaline, which is a 1:2 mol ratio mixture of choline chloride and ethylene glycol. It is shown that for the majority of metals studied a quasi-...

  16. Diffusion and ionic conductivity in solid electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Mundy, J. N.

    1979-01-01

    In ionic solids, the most usual experimental method of determining the correlation factor (f) has been a comparison of tracer diffusion and ionic conductivity. Theoretical values of f have been determined for many lattice geometries and jump processes and compared with measured values of f as a means of determining the atomic jump process. This paper considers the problems of applying this technique to solid electrolytes where the concentration of defects responsible for diffusion is comparable to the concentration of the mobile ions. The difficulties of applying the more common experimental techniques are discussed and the present level of theoretical understanding of correlation effects will be outlined.

  17. Inadvertent intrathecal use of ionic contrast agent

    Energy Technology Data Exchange (ETDEWEB)

    Leede, H. van der; Jorens, P.G. [Department of Intensive Care Medicine, University Hospital of Antwerp, Wilrijkstraat 10, 2650 Edegem (Belgium); Parizel, P. [Department of Radiology, University Hospital of Antwerp, Wilrijkstraat 10, 2650 Edegem (Belgium); Cras, P. [Department of Neurology, University Hospital of Antwerp, Wilrijkstraat 10, 2650 Edegem (Belgium)

    2002-07-01

    Intrathecal administration of ionic contrast media may cause severe and fatal neurotoxic reactions due to their hyperosmolarity and ionic nature. They are therefore strictly contraindicated for all radiologic applications involving the central nervous system (e.g., myelography). We present a case in which ioxitalamate was accidentally injected intrathecally. The patient recovered completely due to a combination of the different therapeutic options reported in the literature, including early mechanical ventilation and neuromuscular paralysis, aggressive control of seizures, elevation of head and trunk to prevent cephalad migration of contrast, steroids, cerebrospinal fluid drainage and lavage and prophylactic antibiotics. (orig.)

  18. Physics of the Lindemann melting rule

    Energy Technology Data Exchange (ETDEWEB)

    Lawson, Andrew C [Los Alamos National Laboratory

    2008-01-01

    We investigate the thermodynamics of melting for 74 distinct chemical elements including several actinides and rare earths. We find that the observed melting points are consistent with a linear relationship between the correlation entropy of the liquid and the Grueneisen constant of the solid, and that the Lindemann rule is well obeyed for the elements with simple structures and less well obeyed for the less symmetric more open structures. No special assumptions are required to explain the melting points of the rare earths or light actinides.

  19. Melt processed high-temperature superconductors

    CERN Document Server

    1993-01-01

    The achievement of large critical currents is critical to the applications of high-temperature superconductors. Recent developments have shown that melt processing is suitable for producing high J c oxide superconductors. Using magnetic forces between such high J c oxide superconductors and magnets, a person could be levitated.This book has grown largely out of research works on melt processing of high-temperature superconductors conducted at ISTEC Superconductivity Research Laboratory. The chapters build on melt processing, microstructural characterization, fundamentals of flux pinning, criti

  20. Rapidly solidified titanium alloys by melt overflow

    Science.gov (United States)

    Gaspar, Thomas A.; Bruce, Thomas J., Jr.; Hackman, Lloyd E.; Brasmer, Susan E.; Dantzig, Jonathan A.; Baeslack, William A., III

    1989-01-01

    A pilot plant scale furnace was designed and constructed for casting titanium alloy strips. The furnace combines plasma arc skull melting techniques with melt overflow rapid solidification technology. A mathematical model of the melting and casting process was developed. The furnace cast strip of a suitable length and width for use with honeycomb structures. Titanium alloys Ti-6Al-4V and Ti-14Al-21 Nb were successfully cast into strips. The strips were evaluated by optical metallography, microhardness measurements, chemical analysis, and cold rolling.