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Sample records for simple ionic compounds

  1. Fun with Ionic Compounds

    ERIC Educational Resources Information Center

    Logerwell, Mollianne G.; Sterling, Donna R.

    2007-01-01

    Ionic bonding is a fundamental topic in high school chemistry, yet it continues to be a concept that students struggle to understand. Even if they understand atomic structure and ion formation, it can be difficult for students to visualize how ions fit together to form compounds. This article describes several engaging activities that help…

  2. Thermodynamic Analysis of Ionic Compounds: Synthetic Applications.

    ERIC Educational Resources Information Center

    Yoder, Claude H.

    1986-01-01

    Shows how thermodynamic cycles can be used to understand trends in heats of formation and aqueous solubilities and, most importantly, how they may be used to choose synthetic routes to new ionic compounds. (JN)

  3. CADDIS Volume 2. Sources, Stressors and Responses: Ionic Strength - Simple Conceptual Diagram

    EPA Pesticide Factsheets

    Introduction to the ionic strength module, when to list ionic strength as a candidate cause, ways to measure ionic strength, simple and detailed conceptual diagrams for ionic strength, ionic strength module references and literature reviews.

  4. A Simple Method for the Calculation of Lattice Energies of Inorganic Ionic Crystals Based on the Chemical Hardness.

    PubMed

    Kaya, Savaş; Kaya, Cemal

    2015-09-08

    This paper presents a new technique for estimation of lattice energies of inorganic ionic compounds using a simple formula. This new method demonstrates the relationship between chemical hardness and lattice energies of ionic compounds. Here chemical hardness values of ionic compounds are calculated via our molecular hardness equation. The results obtained using the present method and comparisons made by considering experimental data and the results from other theoretical methods in the literature showed that the new method allows easy evaluation of lattice energies of inorganic ionic crystals without the need for ab initio calculations and complex calculations.

  5. The Thermochemical Stability of Ionic Noble Gas Compounds.

    ERIC Educational Resources Information Center

    Purser, Gordon H.

    1988-01-01

    Presents calculations that suggest stoichiometric, ionic, and noble gas-metal compounds may be stable. Bases calculations on estimated values of electron affinity, anionic radius for the noble gases and for the Born exponents of resulting crystals. Suggests the desirability of experiments designed to prepare compounds containing anionic,…

  6. Effect of ionic radii on the Curie temperature in Ba1-x-ySrxCayTiO3 compounds

    NASA Astrophysics Data System (ADS)

    Berenov, A.; Le Goupil, F.; Alford, N.

    2016-06-01

    A series of Ba1-x-ySrxCayTiO3 compounds were prepared with varying average ionic radii and cation disorder on A-site. All samples showed typical ferroelectric behavior. A simple empirical equation correlated Curie temperature, TC, with the values of ionic radii of A-site cations. This correlation was related to the distortion of TiO6 octahedra observed during neutron diffraction studies. The equation was used for the selection of compounds with predetermined values of TC. The effects of A-site ionic radii on the temperatures of phase transitions in Ba1-x-ySrxCayTiO3 were discussed.

  7. Effect of ionic radii on the Curie temperature in Ba1-x-ySrxCayTiO3 compounds.

    PubMed

    Berenov, A; Le Goupil, F; Alford, N

    2016-06-21

    A series of Ba1-x-ySrxCayTiO3 compounds were prepared with varying average ionic radii and cation disorder on A-site. All samples showed typical ferroelectric behavior. A simple empirical equation correlated Curie temperature, TC, with the values of ionic radii of A-site cations. This correlation was related to the distortion of TiO6 octahedra observed during neutron diffraction studies. The equation was used for the selection of compounds with predetermined values of TC. The effects of A-site ionic radii on the temperatures of phase transitions in Ba1-x-ySrxCayTiO3 were discussed.

  8. Extraction of organic compounds with room temperature ionic liquids.

    PubMed

    Poole, Colin F; Poole, Salwa K

    2010-04-16

    Room temperature ionic liquids are novel solvents with a rather specific blend of physical and solution properties that makes them of interest for applications in separation science. They are good solvents for a wide range of compounds in which they behave as polar solvents. Their physical properties of note that distinguish them from conventional organic solvents are a negligible vapor pressure, high thermal stability, and relatively high viscosity. They can form biphasic systems with water or low polarity organic solvents and gases suitable for use in liquid-liquid and gas-liquid partition systems. An analysis of partition coefficients for varied compounds in these systems allows characterization of solvent selectivity using the solvation parameter model, which together with spectroscopic studies of solvent effects on probe substances, results in a detailed picture of solvent behavior. These studies indicate that the solution properties of ionic liquids are similar to those of polar organic solvents. Practical applications of ionic liquids in sample preparation include extractive distillation, aqueous biphasic systems, liquid-liquid extraction, liquid-phase microextraction, supported liquid membrane extraction, matrix solvents for headspace analysis, and micellar extraction. The specific advantages and limitations of ionic liquids in these studies is discussed with a view to defining future uses and the need not to neglect the identification of new room temperature ionic liquids with physical and solution properties tailored to the needs of specific sample preparation techniques. The defining feature of the special nature of ionic liquids is not their solution or physical properties viewed separately but their unique combinations when taken together compared with traditional organic solvents.

  9. Ionic surface active compounds in atmospheric aerosols.

    PubMed

    Sukhapan, Jariya; Brimblecombe, Peter

    2002-04-27

    Surfactants in the atmosphere have several potential roles in atmospheric chemistry. They can form films on aqueous surfaces, which lowers the surface tension and possibly delays water evaporation and gaseous transportation across the aqueous interface. They can also increase the solubility of organic compounds in the aqueous phase. Recently, the decrease of surface tension in cloud growing droplets has been suggested as relevant to increases in the number of droplets of smaller size, potentially enhancing cloud albedo. Natural surfactants in the lung aid gas transfer and influence the dissolution rate of aerosol particles, so surfactants in atmospheric aerosols, once inhaled, may interact with pulmonary surfactants. Ambient aerosols were collected from the edge of Norwich, a small city in a largely agricultural region of England, and analysed for surfactants. Methylene blue, a conventional dye for detecting anionic surfactants, has been used as a colorimetric agent. The concentration of surfactants expressed as methylene blue active substances (MBAS) is in the range of 6-170 pmol m(-3)(air). A negative correlation with chloride aerosol indicates that these surfactants are probably not the well-known surfactants derived from marine spray. A more positive correlation with aerosol nitrate and gaseous NOx supports an association with more polluted inland air masses. The surfactants found in aerosols seem to be relatively strong acids, compared with weaker acids such as the long-chain carboxylic acids previously proposed as atmospheric surfactants. Surfactants from the oxidation of organic materials (perhaps vegetation- or soil-derived) seem a likely source of these substances in the atmosphere.

  10. Covalence and ionicity in MgAgAs-type compounds.

    PubMed

    Bende, David; Grin, Yuri; Wagner, Frank R

    2014-07-28

    MgAgAs-type "half-Heusler" compounds are known to realize two out of three possible atomic arrangements of this structure type. The number of transition metal components typically determines which of the alternatives is favored. On the basis of DFT calculations for all three variants of 20 eight- and eighteen-valence-electron compounds, the experimentally observed structural variant was found to be determined by basically two different bonding patterns. They are quantified by employing two complementary position-space bonding measures. The Madelung energy E((M)(QTAIM)) calculated with the QTAIM effective charges reflects contributions of the ionic interactions to the total energy. The sum of nearest-neighbor delocalization indices ςnn characterizes the covalent interactions through electron sharing. With the aid of these quantities, the energetic sequence of the three atomic arrangements for each compound is rationalized. The resulting systematic is used to predict a scenario in which an untypical atomic arrangement becomes most favorable.

  11. Effect of ionic radii on the Curie temperature in Ba1-x-ySrxCayTiO3 compounds

    PubMed Central

    Berenov, A.; Le Goupil, F.; Alford, N.

    2016-01-01

    A series of Ba1-x-ySrxCayTiO3 compounds were prepared with varying average ionic radii and cation disorder on A-site. All samples showed typical ferroelectric behavior. A simple empirical equation correlated Curie temperature, TC, with the values of ionic radii of A-site cations. This correlation was related to the distortion of TiO6 octahedra observed during neutron diffraction studies. The equation was used for the selection of compounds with predetermined values of TC. The effects of A-site ionic radii on the temperatures of phase transitions in Ba1-x-ySrxCayTiO3 were discussed. PMID:27324841

  12. Student Misconceptions in Writing Balanced Equations for Dissolving Ionic Compounds in Water

    ERIC Educational Resources Information Center

    Naah, Basil M.; Sanger, Michael J.

    2012-01-01

    The goal of this study was to identify student misconceptions and difficulties in writing symbolic-level balanced equations for dissolving ionic compounds in water. A sample of 105 college students were asked to provide balanced equations for dissolving four ionic compounds in water. Another 37 college students participated in semi-structured…

  13. Ionic Liquids Beyond Simple Solvents: Glimpses at the State of the Art in Organic Chemistry.

    PubMed

    Kuchenbuch, Andrea; Giernoth, Ralf

    2015-12-01

    Within the last 25 years ionic liquids have written a tremendous success story, which is documented in a nearly uncountable amount of original research papers, reviews, and numerous applications in research and industry. These days, ionic liquids can be considered as a mature class of compounds for many different applications. Frequently, they are used as neoteric solvents for chemical tansformations, and the number of reviews on this field of research is huge. In this focused review, though, we are trying to evaluate the state of the art of ionic liquid chemistry beyond using them simply as solvents for chemical transformations. It is not meant to be a comprehensive overview on the topic; the choice of emphasis and examples rather refects the authors' personal view on the field. We are especially highlighting fields in which we believe the most fundamental developments within the next five years will take place: biomass processing, (chiral) ionic liquids from natural sources, biotransformations, and organic synthesis.

  14. Extending the applicability of the Goldschmidt tolerance factor to arbitrary ionic compounds

    PubMed Central

    Sato, Toyoto; Takagi, Shigeyuki; Deledda, Stefano; Hauback, Bjørn C.; Orimo, Shin-ichi

    2016-01-01

    Crystal structure determination is essential for characterizing materials and their properties, and can be facilitated by various tools and indicators. For instance, the Goldschmidt tolerance factor (T) for perovskite compounds is acknowledged for evaluating crystal structures in terms of the ionic packing. However, its applicability is limited to perovskite compounds. Here, we report on extending the applicability of T to ionic compounds with arbitrary ionic arrangements and compositions. By focussing on the occupancy of constituent spherical ions in the crystal structure, we define the ionic filling fraction (IFF), which is obtained from the volumes of crystal structure and constituent ions. Ionic compounds, including perovskites, are arranged linearly by the IFF, providing consistent results with T. The linearity guides towards finding suitable unit cell and composition, thus tackling the main obstacle for determining new crystal structures. We demonstrate the utility of the IFF by solving the structure of three hydrides with new crystal structures. PMID:27032978

  15. Research on the properties and interactions of simple atomic and ionic systems

    NASA Technical Reports Server (NTRS)

    Novick, R.

    1972-01-01

    Simple ionic systems were studied, such as metastable autoionizing states of the negative He ion, two-photon decay spectrum of metastable He ion, optical excitation with low energy ions, and lifetime measurements of singly ionized Li and metastable He ion. Simple atomic systems were also investigated. Metastable autoionizing atomic energy levels in alkali elements were included, along with lifetime measurements of Cr-53, group 2A isotopes, and alkali metal atoms using level crossing and optical double resonance spectroscopy.

  16. The bond ionicity in ANB8-N compounds from maximally localized Wannier functions

    NASA Astrophysics Data System (ADS)

    Qteish, Abdallah

    2015-07-01

    The bond ionicity in seventy two ANB8-N compounds is investigated according to the recently introduced first-principles ionicity scale, based on the centers of the maximally localized Wannier functions, which has several interesting features. The obtained bond ionicities (qi) are found to exhibit the expected trends, according to electronegativity arguments. In particular, the bond ionicity in the alkaline-earth oxides increases by going from MgO to BaO. A strong crystal structure dependence of qi is observed. A critical value of qi (of 0.91) that separates between the tetrahedrally and octahedrally coordinated systems is inferred directly from the calculated values of qi. The volume dependence of qi is investigated for all the considered compounds and found to reduce by volume decrease for most of the studied systems. The adopted ionicity scale is established as a very strong competitor to the most widely accepted Phillips and Pauling ionicity measures.

  17. Ionic Strength-Induced Formation of Smectite Quasicrystals Enhances Nitroaromatic Compound Sorption

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The influence of ionic strength on nitroaromatic compound sorption from water by K+- and Ca2+-saturated smectite (SWy-2) was examined. The results indicated that sorption of 1,3-dinitrobenzene by K-SWy-2 increased up to 2.2 times as KCl ionic strength increased from 0.01 to 0.30 M. In contrast, sorp...

  18. Partition coefficients of organic compounds in new imidazolium based ionic liquids using inverse gas chromatography.

    PubMed

    Revelli, Anne-Laure; Mutelet, Fabrice; Jaubert, Jean-Noël

    2009-06-05

    Partition coefficients of organic compounds in four ionic liquids: 1-ethanol-3-methylimidazolium tetrafluoroborate, 1-ethanol-3-methylimidazolium hexafluorophosphate, 1,3-dimethylimidazolium dimethylphosphate and 1-ethyl-3-methylimidazolium diethylphosphate were measured using inverse gas chromatography from 303.3 to 332.55K. The influence of gas-liquid and gas-solid interfacial adsorption of different solutes on ionic liquids was also studied. Most of the polar solutes were retained largely by partition while light hydrocarbons were retained predominantly by interfacial adsorption on the ionic liquids studied in this work. The solvation characteristics of the ionic liquids were evaluated using the Abraham solvation parameter model.

  19. Unusual Features of Crystal Structures of Some Simple Copper Compounds

    ERIC Educational Resources Information Center

    Douglas, Bodie

    2009-01-01

    Some simple copper compounds have unusual crystal structures. Cu[subscript 3]N is cubic with N atoms at centers of octahedra formed by 6 Cu atoms. Cu[subscript 2]O (cuprite) is also cubic; O atoms are in tetrahedra formed by 4 Cu atoms. These tetrahedra are linked by sharing vertices forming two independent networks without linkages between them.…

  20. Ionic Liquids Beyond Simple Solvents: Glimpses at the State of the Art in Organic Chemistry

    PubMed Central

    Kuchenbuch, Andrea

    2015-01-01

    Abstract Within the last 25 years ionic liquids have written a tremendous success story, which is documented in a nearly uncountable amount of original research papers, reviews, and numerous applications in research and industry. These days, ionic liquids can be considered as a mature class of compounds for many different applications. Frequently, they are used as neoteric solvents for chemical tansformations, and the number of reviews on this field of research is huge. In this focused review, though, we are trying to evaluate the state of the art of ionic liquid chemistry beyond using them simply as solvents for chemical transformations. It is not meant to be a comprehensive overview on the topic; the choice of emphasis and examples rather refects the authors’ personal view on the field. We are especially highlighting fields in which we believe the most fundamental developments within the next five years will take place: biomass processing, (chiral) ionic liquids from natural sources, biotransformations, and organic synthesis. PMID:27308192

  1. Dynamics of nonspherical compound capsules in simple shear flow

    NASA Astrophysics Data System (ADS)

    Luo, Zheng Yuan; Bai, Bo Feng

    2016-10-01

    The dynamics of an initially ellipsoidal compound capsule in a simple shear flow is investigated numerically using a three-dimensional front-tracking finite-difference model. Membrane bending resistance is included based on Helfrich's energy function besides the resistances against shear deformation and area dilatation governed by the constitutive law of Skalak et al. In this paper, we focus specifically on how the presence of a spherical inner capsule and its size affects the characteristics and transition of various dynamical states of nonspherical compound capsules (i.e., the outer capsule). Significant differences in the dynamical characteristics are observed between compound capsules and homogeneous capsules in both qualitative and quantitative terms. We find the transition from swinging to tumbling can occur at vanishing viscosity mismatch through increasing the inner capsule size alone to a critical value regardless of the initial shape of the nonspherical compound capsule (i.e., prolate or oblate). Besides, for compound capsules with viscosity mismatch, the critical viscosity ratio for the swinging-to-tumbling transition remarkably decreases by increasing the inner capsule size. It is thus concluded that the inner capsule size is a key governing parameter of compound capsule dynamics apart from the capillary number, aspect ratio, and viscosity ratio that have been long identified for homogeneous capsules. Further, we discuss the mechanisms underlying the effects of the inner capsule on the compound capsule dynamics from the viewpoint of the effective viscosity of internal fluid and find that the effects of the inner capsule on compound capsule dynamics are qualitatively similar to that of increasing the internal viscosity on homogeneous capsule dynamics. However, in quantitative terms, the compound capsule cannot be viewed as a homogeneous capsule with higher viscosity as obvious inhomogeneity in fluid stress distribution is induced by the inner membrane.

  2. STUDIES ON THE SENSITIZATION OF ANIMALS WITH SIMPLE CHEMICAL COMPOUNDS

    PubMed Central

    Chase, Merrill W.

    1947-01-01

    Evidence is presented to show that guinea pigs actively sensitized to simple chemical compounds form serum antibodies capable of sensitizing the skin of normal guinea pigs. Skin sites prepared as for the Prausnitz-Küstner test develop immediate-type ("evanescent") reactions with erythema and edema, upon subsequent injection of the corresponding simple compounds or protein conjugates thereof, and give effects resembling transferred reaginic reactions as seen in human beings. The antibodies were obtainable after sensitization by acyl chlorides, acid anhydrides, and also substances of lesser reactivity, picryl chloride and 2:4 dinitrochlorobenzene, which are human allergens. Observations are reported on the specificity of the antibodies and on various details of the reaction. Like effects result when antiprotein immune sera and their corresponding antigens are employed for the test, making it highly probable that the antibodies secured after sensitization to drugs result from immunization by conjugates formed in vivo. The sera obtained after sensitization with simple chemical compounds readily confer passive anaphylaxis, and their capacity for sensitizing the skin declines gradually with progressive heating. It was observed that following a reaction of substantial degree in guinea pig skin the area involved does not fully recover for some days its capacity to react, the effect being a manifestation, it would seem, of what has been termed "non-specific antianaphylaxis." PMID:19871693

  3. Environmental impact of ionic liquids: Automated evaluation of chemical oxygen demand of photochemical degraded compounds.

    PubMed

    Saraiva, M Lúcia Mfs; Costa, Susana; Passos, Marieta

    2017-02-19

    A novel automated fluorimetric technique was developed for the assessment of ionic liquids (ILs) chemical oxygen demand (COD). It was combined a photodegradation step with the perspective of promote ILs degradation. The method was implemented on a sequential injection analysis (SIA) system and based on the reduction of cerium (IV) in the presence of irradiated ILs. The obtained results demonstrated higher COD values for compounds incorporating the chloride anion. Bmim [Cl], bmpyr [Cl] and hmim [Cl] also exhibiting considerable photodegradability ratio. Cholinium cation and methanesulfonate and tetrafluoroborate anions seem to confer resistance to photolysis. The developed methodology proved to be a simple, affordable and robust method. Additionally, it showed a good repeatability under the tested conditions (rsd < 3.5%, n = 10). Therefore, it is expected that the developed approach can be used as screening method for preliminary evaluation of compounds potential impact in the aquatic field. Additionally, the photolysis seems to be an attractive option to promote ILs degradation before their release to wastewater.

  4. Student Conceptions of Ionic Compounds in Solution and the Influences of Sociochemical Norms on Individual Learning

    ERIC Educational Resources Information Center

    Warfa, Abdi-Rizak M.

    2013-01-01

    Using the symbolic interactionist perspective that meaning is constituted as individuals interact with one another, this study examined how group thinking during cooperative inquiry-based activity on chemical bonding theories shaped and influenced college students' understanding of the properties of ionic compounds in solution. The analysis…

  5. Nanoscale Density Fluctuations in Ionic Liquid Binary Mixtures with Nonamphiphilic Compounds: First Experimental Evidence.

    PubMed

    Mariani, Alessandro; Dattani, Rajeev; Caminiti, Ruggero; Gontrani, Lorenzo

    2016-10-04

    A complex mesoscopic organization is observed in systems containing ethylammonium nitrate (EAN) and two nonamphiphilic compounds, using wide and small angle X-ray scattering and molecular dynamics simulations. The macroscopically homogeneous mixtures exhibit a separation where an ionic liquid-rich region is percolating a molecular liquid-rich one, but no unmixing is observed. This effect was already reported in EAN-alcohol mixtures, but the models proposed so far cannot explain this behavior for a nonamphiphilic compound.

  6. A simple recovery process for biodegradable plastics accumulated in cyanobacteria treated with ionic liquids.

    PubMed

    Kobayashi, Daigo; Fujita, Kyoko; Nakamura, Nobuhumi; Ohno, Hiroyuki

    2015-02-01

    Here, we proposed a simple recovery process for poly(3-hydroxybutyrate) (PHB) accumulated in cyanobacteria by using ionic liquids (ILs), which dissolve cyanobacteria but not PHB. First, we investigated the effects of IL polarity on hydrogen-bonding receipt ability (β value) and hydrogen-bonding donating ability (α value) and evaluated the subsequent dissolution of cyanobacteria. We found that ILs having α values higher than approximately 0.4 and β values of approximately 0.9 were suitable for dissolution of cyanobacteria. In particular, 1-ethyl-3-methylimidazolium methylphosphonate ([C2mim][MeO(H)PO2]) was found to dissolve cyanobacteria components, but not PHB. Thus, we verified that PHB produced in cyanobacteria could be separated and recovered by simple filtering after dissolution of cyanobacteria in [C2mim][MeO(H)PO2]. Using this technique, more than 98 % of PHB was obtained on the filter as residues separated from cyanobacteria. Furthermore, [C2mim][MeO(H)PO2] maintained the ability to dissolve cyanobacteria after a simple recycling procedure.

  7. Reclamation of niobium compounds from ionic liquid electrochemical polishing of superconducting radio frequency cavities

    SciTech Connect

    Wixtrom, Alex I.; Buhler, Jessica E.; Reece, Charles E.; Abdel-Fattah, Tarek M.

    2013-06-01

    Recent research has shown that choline chloride (vitamin B4)-based solutions can be used as a greener alternative to acid-based electrochemical polishing solutions. This study demonstrated a successful method for electrochemical deposition of niobium compounds onto the surface of copper substrates using a novel choline chloride-based ionic liquid. Niobium ions present in the ionic liquid solution were dissolved into the solution prior to deposition via electrochemical polishing of solid niobium. A black coating was clearly visible on the surface of the Cu following deposition. This coating was analyzed using scanning electron microscopy (SEM), electron dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), and X-ray fluorescence spectroscopy (XRF). This ionic liquid-based electrochemical deposition method effectively recycles previously dissolved niobium from electrochemical polishing of superconducting radio frequency (SRF) cavities.

  8. Enhanced ionic conductivity of AgI nanowires/AAO composites fabricated by a simple approach

    NASA Astrophysics Data System (ADS)

    Liu, Li-Feng; Lee, Seung-Woo; Li, Jing-Bo; Alexe, Marin; Rao, Guang-Hui; Zhou, Wei-Ya; Lee, Jae-Jong; Lee, Woo; Gösele, Ulrich

    2008-12-01

    AgI nanowires/anodic aluminum oxide (AgI NWs/AAO) composites have been fabricated by a simple approach, which involves the thermal melting of AgI powders on the surface of the AAO membrane, followed by the infiltration of the molten AgI inside the nanochannels. As-prepared AgI nanowires have corrugated outer surfaces and are polycrystalline according to scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations. X-ray diffraction (XRD) shows that a considerable amount of 7H polytype AgI exists in the composites, which is supposed to arise from the interfacial interactions between the embedded AgI and the alumina. AC conductivity measurements for the AgI nanowires/AAO composites exhibit a notable conductivity enhancement by three orders of magnitude at room temperature compared with that of pristine bulk AgI. Furthermore, a large conductivity hysteresis and abnormal conductivity transitions were observed in the temperature-dependent conductivity measurements, from which an ionic conductivity as high as 8.0 × 102 Ω-1 cm-1 was obtained at around 70 °C upon cooling. The differential scanning calorimetry (DSC) result demonstrates a similar phase transition behavior as that found in the AC conductivity measurements. The enhanced ionic conductivity, as well as the abnormal phase transitions, can be explained in terms of the existence of the highly conducting 7H polytype AgI and the formation of well-defined conduction paths in the composites.

  9. Phase equilibria in ionic liquid-aromatic compound mixtures, including benzene fluorination effects.

    PubMed

    Blesic, Marijana; Lopes, José N Canongia; Pádua, Agílio A H; Shimizu, Karina; Gomes, Margarida F Costa; Rebelo, Luís Paulo N

    2009-05-28

    This work extends the scope of previous studies on the phase behavior of mixtures of ionic liquids with benzenes or its derivatives by determining the solid-liquid and liquid-liquid phase diagrams of mixtures containing an ionic liquid and a fluorinated benzene. The systems studied include 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide plus hexafluorobenzene or 1,3,5-trifluorobenzene and 1-ethyl-3-methylimidazolium triflate or N-ethyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide plus benzene. The phase diagrams exhibit different kinds of solid-liquid behavior: the (usual) occurrence of eutectic points; the (not-so-usual) presence of congruent melting points and the corresponding formation of inclusion crystals; or the observation of different ionic liquid crystalline phases (polymorphism). These different types of behavior can be controlled by temperature annealing during crystallization or by the nature of the aromatic compound and can be interpreted, at a molecular level, taking into account the structure of the crystals or liquid mixtures, together with the unique characteristics of ionic liquids, namely the dual nature of their interactions with aromatic compounds.

  10. Extraction of S- and N-Compounds from the Mixture of Hydrocarbons by Ionic Liquids as Selective Solvents

    PubMed Central

    Gabrić, Beata; Sander, Aleksandra; Cvjetko Bubalo, Marina; Macut, Dejan

    2013-01-01

    Liquid-liquid extraction is an alternative method that can be used for desulfurization and denitrification of gasoline and diesel fuels. Recent approaches employ different ionic liquids as selective solvents, due to their general immiscibility with gasoline and diesel, negligible vapor pressure, and high selectivity to sulfur- and nitrogen-containing compounds. For that reason, five imidazolium-based ionic liquids and one pyridinium-based ionic liquid were selected for extraction of thiophene, dibenzothiophene, and pyridine from two model solutions. The influences of hydrodynamic conditions, mass ratio, and number of stages were investigated. Increasing the mass ratio of ionic liquid/model fuel and multistage extraction promotes the desulfurization and denitrification abilities of the examined ionic liquids. All selected ionic liquids can be reused and regenerated by means of vacuum evaporation. PMID:23843736

  11. Simple observation of Streptococcus mutans biofilm by scanning electron microscopy using ionic liquids.

    PubMed

    Asahi, Yoko; Miura, Jiro; Tsuda, Tetsuya; Kuwabata, Susumu; Tsunashima, Katsuhiko; Noiri, Yuichiro; Sakata, Takao; Ebisu, Shigeyuki; Hayashi, Mikako

    2015-12-01

    Scanning electron microscopy (SEM) has been successfully used to image biofilms because of its high resolution and magnification. However, conventional SEM requires dehydration and metal coating of biological samples before observation, and because biofilms consist mainly of water, sample dehydration may influence the biofilm structure. When coated with an ionic liquid, which is a kind of salt that exists in the liquid state at room temperature, biological samples for SEM observation do not require dehydration or metal coating because ionic liquids do not evaporate under vacuum conditions and are electrically conductive. This study investigates the ability of ionic liquids to allow SEM observation of Streptococcus mutans biofilms compared with conventional coating methods. Two hydrophilic and two hydrophobic ionic liquids, all of which are electronic conductors, are used. Compared with samples prepared by the conventional method, the ionic-liquid-treated samples do not exhibit a fibrous extracellular matrix structure and cracking on the biofilm surface. The hydrophilic ionic liquids give clearer images of the biofilm structure than those of the hydrophobic ionic liquids. This study finds that ionic liquids are useful for allowing the observation of biofilms by SEM without preparation by dehydration and metal coating.

  12. Binary and ternary ionic compounds in the outer crust of a cold nonaccreting neutron star

    NASA Astrophysics Data System (ADS)

    Chamel, N.; Fantina, A. F.

    2016-12-01

    The outer crust of a cold nonaccreting neutron star has been generally assumed to be stratified into different layers, each of which consists of a pure body-centered cubic ionic crystal in a charge compensating background of highly degenerate electrons. The validity of this assumption is examined by analyzing the stability of multinary ionic compounds in dense stellar matter. It is thus shown that their stability against phase separation is uniquely determined by their structure and their composition irrespective of the stellar conditions. However, equilibrium with respect to weak and strong nuclear processes imposes very stringent constraints on the composition of multinary compounds, and thereby on their formation. By examining different cubic and noncubic lattices, it is found that substitutional compounds having the same structure as cesium chloride are the most likely to exist in the outer crust of a nonaccreting neutron star. The presence of ternary compounds is also investigated. Very accurate analytical expressions are obtained for the threshold pressure, as well as for the densities of the different phases irrespective of the degree of relativity of the electron gas. Finally, numerical calculations of the ground-state structure and of the equation of state of the outer crust of a cold nonaccreting neutron star are carried out using recent experimental and microscopic nuclear mass tables.

  13. Ionic-Liquid-Mediated Extraction and Separation Processes for Bioactive Compounds: Past, Present, and Future Trends.

    PubMed

    Ventura, Sónia P M; E Silva, Francisca A; Quental, Maria V; Mondal, Dibyendu; Freire, Mara G; Coutinho, João A P

    2017-02-02

    Ionic liquids (ILs) have been proposed as promising media for the extraction and separation of bioactive compounds from the most diverse origins. This critical review offers a compilation on the main results achieved by the use of ionic-liquid-based processes in the extraction and separation/purification of a large range of bioactive compounds (including small organic extractable compounds from biomass, lipids, and other hydrophobic compounds, proteins, amino acids, nucleic acids, and pharmaceuticals). ILs have been studied as solvents, cosolvents, cosurfactants, electrolytes, and adjuvants, as well as used in the creation of IL-supported materials for separation purposes. The IL-based processes hitherto reported, such as IL-based solid-liquid extractions, IL-based liquid-liquid extractions, IL-modified materials, and IL-based crystallization approaches, are here reviewed and compared in terms of extraction and separation performance. The key accomplishments and future challenges to the field are discussed, with particular emphasis on the major lacunas found within the IL community dedicated to separation processes and by suggesting some steps to overcome the current limitations.

  14. Chemical association in simple models of molecular and ionic fluids. III. The cavity function

    NASA Astrophysics Data System (ADS)

    Zhou, Yaoqi; Stell, George

    1992-01-01

    Exact equations which relate the cavity function to excess solvation free energies and equilibrium association constants are rederived by using a thermodynamic cycle. A zeroth-order approximation, derived previously by us as a simple interpolation scheme, is found to be very accurate if the associative bonding occurs on or near the surface of the repulsive core of the interaction potential. If the bonding radius is substantially less than the core radius, the approximation overestimates the association degree and the association constant. For binary association, the zeroth-order approximation is equivalent to the first-order thermodynamic perturbation theory (TPT) of Wertheim. For n-particle association, the combination of the zeroth-order approximation with a ``linear'' approximation (for n-particle distribution functions in terms of the two-particle function) yields the first-order TPT result. Using our exact equations to go beyond TPT, near-exact analytic results for binary hard-sphere association are obtained. Solvent effects on binary hard-sphere association and ionic association are also investigated. A new rule which generalizes Le Chatelier's principle is used to describe the three distinct forms of behaviors involving solvent effects that we find. The replacement of the dielectric-continuum solvent model by a dipolar hard-sphere model leads to improved agreement with an experimental observation. Finally, equation of state for an n-particle flexible linear-chain fluid is derived on the basis of a one-parameter approximation that interpolates between the generalized Kirkwood superposition approximation and the linear approximation. A value of the parameter that appears to be near optimal in the context of this application is obtained from comparison with computer-simulation data.

  15. Chemical association in simple models of molecular and ionic fluids. III. The cavity function

    SciTech Connect

    Zhou, Y. ); Stell, G. )

    1992-01-15

    Exact equations which relate the cavity function to excess solvation free energies and equilibrium association constants are rederived by using a thermodynamic cycle. A zeroth-order approximation, derived previously by us as a simple interpolation scheme, is found to be very accurate if the associative bonding occurs on or near the surface of the repulsive core of the interaction potential. If the bonding radius is substantially less than the core radius, the approximation overestimates the association degree and the association constant. For binary association, the zeroth-order approximation is equivalent to the first-order thermodynamic perturbation theory (TPT) of Wertheim. For {ital n}-particle association, the combination of the zeroth-order approximation with a linear'' approximation (for {ital n}-particle distribution functions in terms of the two-particle function) yields the first-order TPT result. Using our exact equations to go beyond TPT, near-exact analytic results for binary hard-sphere association are obtained. Solvent effects on binary hard-sphere association and ionic association are also investigated. A new rule which generalizes Le Chatelier's principle is used to describe the three distinct forms of behaviors involving solvent effects that we find. The replacement of the dielectric-continuum solvent model by a dipolar hard-sphere model leads to improved agreement with an experimental observation. Finally, equation of state for an {ital n}-particle flexible linear-chain fluid is derived on the basis of a one-parameter approximation that interpolates between the generalized Kirkwood superposition approximation and the linear approximation. A value of the parameter that appears to be near optimal in the context of this application is obtained from comparison with computer-simulation data.

  16. Specific ionic effect for simple and rapid colorimetric sensing assays of amino acids using gold nanoparticles modified with task-specific ionic liquid.

    PubMed

    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.

  17. STUDIES ON THE SENSITIZATION OF ANIMALS WITH SIMPLE CHEMICAL COMPOUNDS

    PubMed Central

    Landsteiner, K.; Di Somma, A. A.

    1938-01-01

    With the view of making new types of chemicals accessible for investigations on drug hypersensitiveness, methods have been devised for sensitizing animals with diazomethane and mustard oil, two non-aromatic compounds. Guinea pigs have been sensitized to diazomethane, a substance of high reactivity and known to cause severe allergic effects in man. With the second substance, allylisothiocyanate, likewise capable of forming conjugates with substances in the animal body, sensitization effects have been obtained in man and in hogs. Sensitization in human beings was successful with one out of six individuals treated. The observations indicate species and individual differences as regards the ability to become sensitized to various chemical compounds. PMID:19870801

  18. STUDIES ON THE SENSITIZATION OF ANIMALS WITH SIMPLE CHEMICAL COMPOUNDS

    PubMed Central

    Landsteiner, K.; Di Somma, A. A.

    1940-01-01

    Sensitization of guinea pigs to picric acid was obtained by application of oil solutions to the skin, preferably on inflamed sites or by treatment with a compound of picric acid with n-butyl-p-aminobenzoate. The lesions obtained in sensitive animals on superficial administration bore resemblance to human eczema. It seems probable that picric acid sensitization is an instance where a substance does not sensitize directly but after conversion into a more reactive compound, a principle which should be of wider application to instances where the original substance does not readily form conjugates. PMID:19871030

  19. Ammonia as a case study for the spontaneous ionization of a simple hydrogen-bonded compound.

    PubMed

    Palasyuk, Taras; Troyan, Ivan; Eremets, Mikhail; Drozd, Vadym; Medvedev, Sergey; Zaleski-Ejgierd, Patryk; Magos-Palasyuk, Ewelina; Wang, Hongbo; Bonev, Stanimir A; Dudenko, Dmytro; Naumov, Pavel

    2014-03-24

    Modern ab initio calculations predict ionic and superionic states in highly compressed water and ammonia. The prediction apparently contradicts state-of-the-art experimentally established phase diagrams overwhelmingly dominated by molecular phases. Here we present experimental evidence that the threshold pressure of ~120 GPa induces in molecular ammonia the process of autoionization to yet experimentally unknown ionic compound--ammonium amide. Our supplementary theoretical simulations provide valuable insight into the mechanism of autoionization showing no hydrogen bond symmetrization along the transformation path, a remarkably small energy barrier between competing phases and the impact of structural rearrangement contribution on the overall conversion rate. This discovery is bridging theory and experiment thus opening new possibilities for studying molecular interactions in hydrogen-bonded systems. Experimental knowledge on this novel ionic phase of ammonia also provides strong motivation for reconsideration of the theory of molecular ice layers formation and dynamics in giant gas planets.

  20. The role of ionic surfactants on the solubilization of cyclohexenone compounds in aqueous media.

    PubMed

    Nisar, Jan; Khan, Muhammad Anas; Badshah, Amir; Ilyas, Mohammad; Khan, Gul Tiaz

    2014-01-01

    The solubilization and partitioning study of five newly synthesized organic compounds (Cyclohexenone Carboxylates) with ionic surfactants, sodium dodecylsulphate (SDS) and cetyltrimethylammonium bromide (CTAB) was studied using ultraviolet-visible absorption spectroscopy technique. The differential spectroscopic technique was employed to study the partition coefficient (K(x)) of organic molecules between bulk water phase and the miceller phase. The values of partitioning coefficient were in the range 29.714 × 10(3) to 5.46 × 10(6). The standard free energy of partitioning (ΔG(op)) was also determined, which was found out in the range of -25 to -38 kJ /mole and shows the stability of the system. The results show that the cyclohexenone carboxylate compounds have great interactions with CTAB as compared to SDS.

  1. Enzymatic hybridization of α-lipoic acid with bioactive compounds in ionic solvents.

    PubMed

    Papadopoulou, Athena A; Katsoura, Maria H; Chatzikonstantinou, Alexandra; Kyriakou, Eleni; Polydera, Angeliki C; Tzakos, Andreas G; Stamatis, Haralambos

    2013-05-01

    The lipase-catalyzed molecular hybridization of α-lipoic acid (LA) with bioactive compounds pyridoxine, tyrosol and tyramine was performed in ionic solvents and deep eutectic solvents. The biocatalytic reactions were catalyzed by Candida antarctica lipase B immobilized onto various functionalized multi-walled carbon nanotubes (f-CNTs-CaLB), as well as by commercial Novozym 435. The use of f-CNTs-CaLB leads, in most cases, to higher conversion yields as compared to Novozym 435. The nature and ion composition of ionic solvents affect the performance of the biocatalytic process. The highest conversion yield was observed in (mtoa)NTf2. The high enzyme stability and the relatively low solubility of substrates in specific media account for the improved biocatalytic synthesis of molecular hybrids of LA. Principal component analysis was used to screen for potential lipoxygenase inhibitors. In vitro studies showed that the synthesized compounds exhibit up to 10-fold increased inhibitory activity on lipoxygenase mediated lipid peroxidation as compared to parent molecules.

  2. Application of ionic liquid for extraction and separation of bioactive compounds from plants.

    PubMed

    Tang, Baokun; Bi, Wentao; Tian, Minglei; Row, Kyung Ho

    2012-09-01

    In recent years, ionic liquids (ILs), as green and designer solvents, have accelerated research in analytical chemistry. This review highlights some of the unique properties of ILs and provides an overview of the preparation and application of IL or IL-based materials to extract bioactive compounds in plants. IL or IL-based materials in conjunction with liquid-liquid extraction (LLE), ultrasonic-assisted extraction (UAE), microwave-assisted extraction (MAE), high performance liquid chromatography (HPLC) and solid-phase extraction (SPE) analytical technologies etc., have been applied successfully to the extraction or separation of bioactive compounds from plants. This paper reviews the available data and references to examine the advantages of IL and IL-based materials in these applications. In addition, the main target compounds reviewed in this paper are bioactive compounds with multiple therapeutic effects and pharmacological activities. Based on the importance of the targets, this paper reviews the applications of ILs, IL-based materials or co-working with analytical technologies. The exploitation of new applications of ILs on the extraction of bioactive compounds from plant samples is expected to increase.

  3. Global atmospheric budget of simple monocyclic aromatic compounds

    NASA Astrophysics Data System (ADS)

    Cabrera-Perez, David; Taraborrelli, Domenico; Sander, Rolf; Pozzer, Andrea

    2016-06-01

    The global atmospheric budget and distribution of monocyclic aromatic compounds is estimated, using an atmospheric chemistry general circulation model. Simulation results are evaluated with an ensemble of surface and aircraft observations with the goal of understanding emission, production and removal of these compounds.Anthropogenic emissions provided by the RCP database represent the largest source of aromatics in the model (≃ 23 TgC year-1) and biomass burning from the GFAS inventory the second largest (≃ 5 TgC year-1). The simulated chemical production of aromatics accounts for ≃ 5 TgC year-1. The atmospheric burden of aromatics sums up to 0.3 TgC. The main removal process of aromatics is photochemical decomposition (≃ 27 TgC year-1), while wet and dry deposition are responsible for a removal of ≃ 4 TgC year-1.Simulated mixing ratios at the surface and elsewhere in the troposphere show good spatial and temporal agreement with the observations for benzene, although the model generally underestimates mixing ratios. Toluene is generally well reproduced by the model at the surface, but mixing ratios in the free troposphere are underestimated. Finally, larger discrepancies are found for xylenes: surface mixing ratios are not only overestimated but also a low temporal correlation is found with respect to in situ observations.

  4. Ionic liquid solutions as extractive solvents for value-added compounds from biomass

    PubMed Central

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

    2014-01-01

    In the past few years, the number of studies regarding the application of ionic liquids (ILs) as alternative solvents to extract value-added compounds from biomass has been growing. Based on an extended compilation and analysis of the data hitherto reported, the main objective of this review is to provide an overview on the use of ILs and their mixtures with molecular solvents for the extraction of value-added compounds present in natural sources. The ILs (or IL solutions) investigated as solvents for the extraction of natural compounds, such as alkaloids, flavonoids, terpenoids, lipids, among others, are outlined. The extraction techniques employed, namely solid–liquid extraction, and microwave-assisted and ultrasound-assisted extractions, are emphasized and discussed in terms of extraction yields and purification factors. Furthermore, the evaluation of the IL chemical structure and the optimization of the process conditions (IL concentration, temperature, biomass–solvent ratio, etc.) are critically addressed. Major conclusions on the role of the ILs towards the extraction mechanisms and improved extraction yields are additionally provided. The isolation and recovery procedures of the value-added compounds are ascertained as well as some scattered strategies already reported for the IL solvent recovery and reusability. Finally, a critical analysis on the economic impact versus the extraction performance of IL-based methodologies was also carried out and is here presented and discussed. PMID:25516718

  5. Ionic liquid solutions as extractive solvents for value-added compounds from biomass.

    PubMed

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

    2014-12-01

    In the past few years, the number of studies regarding the application of ionic liquids (ILs) as alternative solvents to extract value-added compounds from biomass has been growing. Based on an extended compilation and analysis of the data hitherto reported, the main objective of this review is to provide an overview on the use of ILs and their mixtures with molecular solvents for the extraction of value-added compounds present in natural sources. The ILs (or IL solutions) investigated as solvents for the extraction of natural compounds, such as alkaloids, flavonoids, terpenoids, lipids, among others, are outlined. The extraction techniques employed, namely solid-liquid extraction, and microwave-assisted and ultrasound-assisted extractions, are emphasized and discussed in terms of extraction yields and purification factors. Furthermore, the evaluation of the IL chemical structure and the optimization of the process conditions (IL concentration, temperature, biomass-solvent ratio, etc.) are critically addressed. Major conclusions on the role of the ILs towards the extraction mechanisms and improved extraction yields are additionally provided. The isolation and recovery procedures of the value-added compounds are ascertained as well as some scattered strategies already reported for the IL solvent recovery and reusability. Finally, a critical analysis on the economic impact versus the extraction performance of IL-based methodologies was also carried out and is here presented and discussed.

  6. Shock-Synthesis of Prebiotic Compounds in Impacting Simple Ices

    NASA Astrophysics Data System (ADS)

    Goldman, N.

    2013-12-01

    expansion and cooling. Aromatic compounds could be prebiotic precursors for a number of life-building molecules, including nucleotides of RNA and DNA. At higher peak shock conditions (48-60 GPa, 3700-4600 K), the C-C and C-N bonded oligomers decompose upon expansion and cooling to form precursors to amino acids and other complex prebiotic chemical species, such as long chain alkanes, alkenes, CH4 and formaldehyde. All shock compression simulations we have conducted between 36-62 GPa and 2800-4700 K have produced significant quantities of HCN and HNC upon expansion and cooling to ambient conditions. These products can yield amino acids, pyrimidines, and/or purines in aqueous solution. Our results indicate that impacts from cometary ices could have yielded a wide variety of prebiotic organic material in addition to amino acids on early Earth, independent of external features such as the presence of a catalyst, illuminating UV radiation, or pre-existing conditions on a planet. Knowledge of the chemical properties of the types of prebiotic molecules under extreme thermodynamic conditions studied herein is needed for a complete understanding of the role of impacting icy materials in the formation of life-building compounds. * This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  7. Ionic liquids as an electrolyte for the electro synthesis of organic compounds.

    PubMed

    Kathiresan, Murugavel; Velayutham, David

    2015-12-25

    The use of ionic liquids (ILs) as a solvent and an electrolyte for electro organic synthesis has been reviewed. To date several ILs exist, however the ILs based on tetraalkylammonium, pyrrolidinium, piperidinium and imidazolium cations with BF4(-), PF6(-), and TFSI anions have been widely used and explored the most. Electro organic synthesis in ionic liquid media leading to the synthesis of a wide range of organic compounds has been discussed. Anodic oxidation or cathodic reduction will generate radical cation or anion intermediates, respectively. These radicals can undergo self coupling or coupling with other molecules yielding organic compounds of interest. The cation of the IL is known to stabilize the radical anion extensively. This stabilization effect has a specific impact on the electrochemical CO2 reduction and coupling to various organics. The relative stability of the intermediates in IL leads to the formation of specific products in higher yields. Electrochemical reduction of imidazolium or thiazolium based ILs generates N-heterocyclic carbenes that have been shown to catalyze a wide range of base or nucleophile catalyzed organic reactions in IL media, an aspect that falls into the category of organocatalysis. Electrochemical fluorination or selective electrochemical fluorination is another fascinating area that delivers selectively fluorinated organic products in Et3N·nHF or Et4NF·nHF adducts (IL) via anodic oxidation. Oxidative polymerization in ILs has been explored the most; although morphological changes were observed compared to the conventional methods, polymers were obtained in good yields and in some cases ILs were used as dopants to improve the desired properties.

  8. Monte Carlo simulation of diffusion and ionic conductivity in a simple cubic random alloy via the interstitialcy mechanism

    NASA Astrophysics Data System (ADS)

    Wilangowski, F.; Stolwijk, N. A.

    2015-12-01

    This Monte Carlo study deals with mass and charge transport in binary ionic alloys governed by interstitialcy defects acting as diffusion vehicles. In particular, we calculate tracer correlation factors {{f}\\text{A}} and {{f}\\text{B}} in a simple cubic random alloy AB for diffusion via the collinear interstitialcy mechanism as a function of composition and jump frequency ratio {{w}\\text{A}}\\ll {{w}\\text{B}} . Interstitialcy correlation factors {{f}\\text{I}} , which play a crucial role in the interpretation of ion-conductivity data, are also determined. The evaluation of partial correlation factors provides insight into the types of jumps that mostly contribute to the different transport processes under consideration. Examination of the percolation behaviour yields the site-percolation threshold of the mobile component B for {{w}\\text{A}}=0 . Surprisingly, a unique second-order threshold composition is found, which relates to the abundance of different interstitialcy jump types when {{w}\\text{A}}/{{w}\\text{B}} . Both numerically obtained threshold values are accurately reproduced by estimated analytical expressions based on simple arguments. Practical implications of the simulation results are explored by calculating tracer diffusivity ratios D\\text{A}*/D\\text{B}* and by comparing self-diffusion with ionic conductivity using the Nernst-Einstein equation.

  9. Monte Carlo simulation of diffusion and ionic conductivity in a simple cubic random alloy via the interstitialcy mechanism.

    PubMed

    Wilangowski, F; Stolwijk, N A

    2015-12-23

    This Monte Carlo study deals with mass and charge transport in binary ionic alloys governed by interstitialcy defects acting as diffusion vehicles. In particular, we calculate tracer correlation factors f(A) and f(B) in a simple cubic random alloy AB for diffusion via the collinear interstitialcy mechanism as a function of composition and jump frequency ratio wA/wB. [corrected]. Interstitialcy correlation factors f(I), which play a crucial role in the interpretation of ion-conductivity data, are also determined. The evaluation of partial correlation factors provides insight into the types of jumps that mostly contribute to the different transport processes under consideration. Examination of the percolation behaviour yields the site-percolation threshold of the mobile component B for w(A) = 0. Surprisingly, a unique second-order threshold composition is found, which relates to the abundance of different interstitialcy jump types when wA < wB [corrected]. Both numerically obtained threshold values are accurately reproduced by estimated analytical expressions based on simple arguments. Practical implications of the simulation results are explored by calculating tracer diffusivity ratios D*(A)/D*(B) and by comparing self-diffusion with ionic conductivity using the Nernst-Einstein equation.

  10. "Sticky Ions": A Student-Centered Activity Using Magnetic Models to Explore the Dissolving of Ionic Compounds

    ERIC Educational Resources Information Center

    Ryan, Sheila; Herrington, Deborah G.

    2014-01-01

    Understanding what happens at the particulate level when ionic compounds dissolve in water is difficult for many students, yet this understanding is critical in explaining many macroscopic observations. This article describes a student-centered activity designed to help strengthen students' conceptual understanding of this process at the…

  11. On the Extraction of Aromatic Compounds from Hydrocarbons by Imidazolium Ionic Liquids

    PubMed Central

    Cassol, Cláudia C.; Umpierre, Alexandre P.; Ebeling, Günter; Ferrera, Bauer; Chiaro, Sandra S. X.; Dupont, Jairton

    2007-01-01

    The liquid-liquid equilibrium for the ternary system formed by n-octane and aromatic (alkylbenzenes) and heteroaromatic compounds (nitrogen and sulfur containing heterocyles) and 1-alkyl-3-methylimidazolium ionic liquids (ILs) associated with various anions has been investigated. The selectivity on the extraction of a specific aromatic compound is influenced by anion volume, hydrogen bond strength between the anion and the imidazolium cation and the length of the 1-methyl-3-alkylimidazolium alkyl side chain. The interaction of alkylbenzenes and sulfur heterocyles with the IL is preferentially through CH-π hydrogen bonds and the quantity of these aromatics in the IL phase decreases with the increase of the steric hindrance imposed by the substituents on the aromatic nucleus. In the case of nitrogen heterocycles the interaction occurs preferentially through N(heteroaromatic)-H(imidazolium) hydrogen bonds and the extraction process is largely controlled by the nitrogen heterocycle pKa. Competitive extraction experiments suggest that benzene, pyridine and dibenzothiophene do not compete for the same hydrogen bond sites of the IL.

  12. Ionic liquids in chromatographic and electrophoretic techniques: toward additional improvements in the separation of natural compounds

    PubMed Central

    Freire, Carmen S. R.; Coutinho, João A. P.; Silvestre, Armando J. D.; Freire, Mara G.

    2016-01-01

    Due to their unique properties, in recent years, ionic liquids (ILs) have been largely investigated in the field of analytical chemistry. Particularly during the last sixteen years, they have been successfully applied in the chromatographic and electrophoretic analysis of value-added compounds extracted from biomass. Considering the growing interest in the use of ILs in this field, this critical review provides a comprehensive overview on the improvements achieved using ILs as constituents of mobile or stationary phases in analytical techniques, namely in capillary electrophoresis and its different modes, in high performance liquid chromatography, and in gas chromatography, for the separation and analysis of natural compounds. The impact of the IL chemical structure and the influence of secondary parameters, such as the IL concentration, temperature, pH, voltage and analysis time (when applied), are also critically addressed regarding the achieved separation improvements. Major conclusions on the role of ILs in the separation mechanisms and the performance of these techniques in terms of efficiency, resolution and selectivity are provided. Based on a critical analysis of all published results, some target-oriented ILs are suggested. Finally, current drawbacks and future challenges in the field are highlighted. In particular, the design and use of more benign and effective ILs as well as the development of integrated (and thus more sustainable) extraction–separation processes using IL aqueous solutions are suggested within a green chemistry perspective. PMID:27667965

  13. Ionic liquids in chromatographic and electrophoretic techniques: toward additional improvements in the separation of natural compounds.

    PubMed

    Soares, Belinda; Passos, Helena; Freire, Carmen S R; Coutinho, João A P; Silvestre, Armando J D; Freire, Mara G

    2016-09-07

    Due to their unique properties, in recent years, ionic liquids (ILs) have been largely investigated in the field of analytical chemistry. Particularly during the last sixteen years, they have been successfully applied in the chromatographic and electrophoretic analysis of value-added compounds extracted from biomass. Considering the growing interest in the use of ILs in this field, this critical review provides a comprehensive overview on the improvements achieved using ILs as constituents of mobile or stationary phases in analytical techniques, namely in capillary electrophoresis and its different modes, in high performance liquid chromatography, and in gas chromatography, for the separation and analysis of natural compounds. The impact of the IL chemical structure and the influence of secondary parameters, such as the IL concentration, temperature, pH, voltage and analysis time (when applied), are also critically addressed regarding the achieved separation improvements. Major conclusions on the role of ILs in the separation mechanisms and the performance of these techniques in terms of efficiency, resolution and selectivity are provided. Based on a critical analysis of all published results, some target-oriented ILs are suggested. Finally, current drawbacks and future challenges in the field are highlighted. In particular, the design and use of more benign and effective ILs as well as the development of integrated (and thus more sustainable) extraction-separation processes using IL aqueous solutions are suggested within a green chemistry perspective.

  14. Homoleptic alkaline earth metal bis(trifluoromethanesulfonyl)imide complex compounds obtained from an ionic liquid.

    PubMed

    Babai, Arash; Mudring, Anja-Verena

    2006-04-17

    The first homoleptic alkaline earth bis(trifluoromethanesulfonyl)imide (Tf2N) complexes [mppyr]2[Ca(Tf2N)4], [mppyr]2[Sr(Tf2N)4], and [mppyr][Ba(Tf2N)3] were crystallized from a solution of the respective alkaline earth bis(trifluoromethanesulfonyl)imide and the ionic liquid [mppyr][Tf2N] (mppyr = 1,1-N-methyl-N-propylpyrrolidinium). In the calcium and strontium compounds, the alkaline earth metal (AE) is coordinated by four bidentately chelating Tf2N ligands to form isolated (distorted) square antiprismatic [AE(Tf2N)4]2- complexes which are separated by N-methyl-N-propylpyrrolidinium cations. In contrast, the barium compound, [mppyr][Ba(Tf2N)3], forms an extended structure. Here the alkaline earth cation is surrounded by six oxygen atoms belonging to three Tf2N- anions which coordinate in a bidentate chelating fashion. Three further oxygen atoms of the same ligands are linking the Ba2+ cations to infinite (infinity)(1)[Ba(Tf2N)3] chains.

  15. Evaluation and comparison of effective connectivity during simple and compound limb motor imagery.

    PubMed

    Yi, Weibo; Zhang, Lixin; Wang, Kun; Xiao, Xiaolin; He, Feng; Zhao, Xin; Qi, Hongzhi; Zhou, Peng; Wan, Baikun; Ming, Dong

    2014-01-01

    Motor imagery (MI) has been demonstrated beneficial in motor rehabilitation in patients with movement disorders. In contrast with simple limb motor imagery, less work was reported about the effective connectivity networks of compound limb motor imagery which involves several parts of limbs. This work aimed to investigate the differences of information flow patterns between simple limb motor imagery and compound limb motor imagery. Ten subjects participated in the experiment involving three tasks of simple limb motor imagery (left hand, right hand, feet) and three tasks of compound limb motor imagery (both hands, left hand combined with right foot, right hand combined with left foot). The causal interactions among different neural regions were evaluated by Short-time Directed Transfer Function (SDTF). Quite different from the networks of simple limb motor imagery, more effective interactions overlying larger brain regions were observed during compound limb motor imagery. These results imply that there exist significant differences in the patterns of EEG activity flow between simple limb motor imagery and compound limb motor imagery, which present more complex networks and could be utilized in motor rehabilitation for more benefit in patients with movement disorders.

  16. Sputter deposition onto ionic liquids: Simple and clean synthesis of highly dispersed ultrafine metal nanoparticles

    SciTech Connect

    Torimoto, Tsukasa; Okazaki, Ken-ichi; Kiyama, Tomonori; Hirahara, Kaori; Tanaka, Nobuo; Kuwabata, Susumu

    2006-12-11

    Sputter deposition of gold (Au) onto ionic liquids (ILs) resulted in the formation of highly dispersed Au nanoparticles without additional chemical species, such as reducing and/or stabilizing agents. The Au nanoparticles in 1-ethyl-3-methylimidazolium tetrafluoroborate had an average diameter (d{sub av}) of 5.5 nm with a standard deviation ({sigma}) of 0.86 nm, while sputter deposition onto N,N,N-trimethyl-N-propylammonium bis(trifluoromethanesulfonyl)imide resulted in the formation of much smaller Au nanoparticles with d{sub av} of 1.9 nm and {sigma} of 0.46 nm. Prolongation of sputtering time results in a higher concentration of Au nanoparticles in ILs, but did not cause a remarkable change in their size.

  17. Room temperature ionic liquids: A simple model. Effect of chain length and size of intermolecular potential on critical temperature

    NASA Astrophysics Data System (ADS)

    Chapela, Gustavo A.; Guzmán, Orlando; Díaz-Herrera, Enrique; del Río, Fernando

    2015-04-01

    A model of a room temperature ionic liquid can be represented as an ion attached to an aliphatic chain mixed with a counter ion. The simple model used in this work is based on a short rigid tangent square well chain with an ion, represented by a hard sphere interacting with a Yukawa potential at the head of the chain, mixed with a counter ion represented as well by a hard sphere interacting with a Yukawa potential of the opposite sign. The length of the chain and the depth of the intermolecular forces are investigated in order to understand which of these factors are responsible for the lowering of the critical temperature. It is the large difference between the ionic and the dispersion potentials which explains this lowering of the critical temperature. Calculation of liquid-vapor equilibrium orthobaric curves is used to estimate the critical points of the model. Vapor pressures are used to obtain an estimate of the triple point of the different models in order to calculate the span of temperatures where they remain a liquid. Surface tensions and interfacial thicknesses are also reported.

  18. Room temperature ionic liquids: A simple model. Effect of chain length and size of intermolecular potential on critical temperature.

    PubMed

    Chapela, Gustavo A; Guzmán, Orlando; Díaz-Herrera, Enrique; del Río, Fernando

    2015-04-21

    A model of a room temperature ionic liquid can be represented as an ion attached to an aliphatic chain mixed with a counter ion. The simple model used in this work is based on a short rigid tangent square well chain with an ion, represented by a hard sphere interacting with a Yukawa potential at the head of the chain, mixed with a counter ion represented as well by a hard sphere interacting with a Yukawa potential of the opposite sign. The length of the chain and the depth of the intermolecular forces are investigated in order to understand which of these factors are responsible for the lowering of the critical temperature. It is the large difference between the ionic and the dispersion potentials which explains this lowering of the critical temperature. Calculation of liquid-vapor equilibrium orthobaric curves is used to estimate the critical points of the model. Vapor pressures are used to obtain an estimate of the triple point of the different models in order to calculate the span of temperatures where they remain a liquid. Surface tensions and interfacial thicknesses are also reported.

  19. Simple and mass-produced mechanochemical preparation of graphene nanosheet/polyaniline composite assisted with bifunctional ionic liquid

    NASA Astrophysics Data System (ADS)

    Lu, Xiangjun; Dou, Hui

    2016-05-01

    Graphene nanosheet/polyaniline (GNS/PANI) composite was prepared by a simple and mass-produced mechanochemical method, where the functionalized ionic liquid 1-(3-sulfonic acid) propyl-3-methylimidazolium hydrogen sulfate conducts as not only the dispersant of GNS but also the dopant of PANI. The GNS/PANI composite characterized by Fourier transformation infrared spectra, UV-Vis spectra and X-ray diffraction shows that the resulting PANI in composite is in its doped, conductive emeraldine oxidation state. Scanning electron microscope images reveal that the GNS/PANI composite with PANI uniformly coated on the surface of GNS is randomly stacking. Compared with pure PANI, the GNS/PANI composite has higher electrical conductivity, better thermal stability and electrochemical activity due to the presence of GNS.

  20. A simple approach for morphology tailoring of alginate particles by manipulation ionic nature of polyurethanes.

    PubMed

    Daemi, Hamed; Barikani, Mehdi; Barmar, Mohammad

    2014-05-01

    A number of different ionic aqueous polyurethane dispersions (PUDs) were synthesized based on NCO-terminated prepolymers. Two different anionic and cationic polyurethane samples were synthesized using dimethylol propionic acid and N-methyldiethanolamine emulsifiers, respectively. Then, proper amounts of PUDs and sodium alginate were mixed to obtain a number of aqueous polyurethane dispersions-sodium alginate (PUD/SA) elastomers. The chemical structure, thermal, morphological, thermo-mechanical and mechanical properties, and hydrophilicity content of the prepared samples were studied by FTIR, EDX, DSC, TGA, SEM, DMTA, tensile testing and contact angle techniques. The cationic polyurethanes and their blends with sodium alginate showed excellent miscibility and highly stretchable properties, while the samples containing anionic polyurethanes and alginate illustrated a poor compatibility and no significant miscibility. The morphology of alginate particles shifted from nanoparticles to microparticles by changing the nature of PUDs from cationic to anionic types. The final cationic elastomers not only showed better mechanical properties but also were formulated easier than anionic samples.

  1. Modified normal-phase ion-pair chromatographic methods for the facile separation and purification of imidazolium-based ionic compounds

    SciTech Connect

    Urban, ND; Schenkel, MR; Robertson, LA; Noble, RD; Gin, DL

    2012-07-04

    lmidazolium- and oligo(imidazolium)-based ionic organic compounds are important in the design of room-temperature ionic liquid materials; however, the chromatographic analysis and separation of such compounds are often difficult. A convenient and inexpensive method for effective thin-layer chromatography (TLC) analysis and column chromatography separation of imidazolium-based ionic compounds is presented. Normal-phase ion-pair TLC is used to effectively analyze homologous mixtures of these ionic compounds. Subsequent separation of the mixtures is performed using ion-pair flash chromatography on normal-phase silica gel, yielding high levels of recovery. This method also results in a complete exchange of the counter anion on the imidazolium compounds to the anion of the ion-pair reagent. (C) 2012 Elsevier Ltd. All rights reserved.

  2. A simple halide-to-anion exchange method for heteroaromatic salts and ionic liquids.

    PubMed

    Alcalde, Ermitas; Dinarès, Immaculada; Ibáñez, Anna; Mesquida, Neus

    2012-04-02

    A broad and simple method permitted halide ions in quaternary heteroaromatic and ammonium salts to be exchanged for a variety of anions using an anion exchange resin (A(-) form) in non-aqueous media. The anion loading of the AER (OH(-) form) was examined using two different anion sources, acids or ammonium salts, and changing the polarity of the solvents. The AER (A(-) form) method in organic solvents was then applied to several quaternary heteroaromatic salts and ILs, and the anion exchange proceeded in excellent to quantitative yields, concomitantly removing halide impurities. Relying on the hydrophobicity of the targeted ion pair for the counteranion swap, organic solvents with variable polarity were used, such as CH(3)OH, CH(3)CN and the dipolar nonhydroxylic solvent mixture CH(3)CN:CH(2)Cl(2) (3:7) and the anion exchange was equally successful with both lipophilic cations and anions.

  3. Adsorption of a Textile Dye on Commercial Activated Carbon: A Simple Experiment to Explore the Role of Surface Chemistry and Ionic Strength

    ERIC Educational Resources Information Center

    Martins, Angela; Nunes, Nelson

    2015-01-01

    In this study, an adsorption experiment is proposed using commercial activated carbon as adsorbent and a textile azo dye, Mordant Blue-9, as adsorbate. The surface chemistry of the activated carbon is changed through a simple oxidation treatment and the ionic strength of the dye solution is also modified, simulating distinct conditions of water…

  4. Thermodynamic characterization of the biocompatible ionic liquid effects on protein model compounds and their functional groups.

    PubMed

    Attri, Pankaj; Venkatesu, Pannuru

    2011-04-14

    The stability of proteins under co-solvent conditions is dependant on the nature of the co-solvent; the co-solvent can alter a protein's properties and structural effects through bimolecular interactions between its functional groups and co-solvent particles. Ionic liquids (ILs) represent a rather diverse class of co-solvents that are combinations of different ions, which are liquids at or close to room temperature. To quantify the bimolecular interactions of protein functional groups with biocompatible ILs, we report the systematic and quantitative apparent transfer free energies (ΔG'(tr)) of a homologous series of cyclic dipeptides (CDs) from water to aqueous solutions of ILs through solubility measurements, as a function of IL concentration at 25 °C under atmospheric pressure. The materials investigated in the present work included the CDs of cyclo(Gly-Gly), cyclo(Ala-Gly), cyclo(Ala-Ala), cyclo(Leu-Ala), and cyclo(Val-Val). The ILs used such as diethylammonium acetate ([Et(2)NH][CH(3)COO], DEAA), triethylammonium acetate ([Et(3)NH][CH(3)COO], TEAA), diethylammonium dihydogen phosphate ([Et(3)NH][H(2)PO(4)], DEAP), triethylammonium dihydogen phosphate ([Et(3)NH][H(2)PO(4)], TEAP), diethylammonium sulfate ([Et(3)NH][HSO(4)], DEAS) and triethylammonium sulfate ([Et(3)NH][HSO(4)], TEAS). We observed positive values of ΔG'(tr) for CDs from water to ILs, indicating that interactions between ILs and CDs are unfavourable, which leads to stabilization of the native structure of CDs. The experimental results were further used for estimating the transfer free energies (Δg'(tr)) of the peptide bond (-CONH-), the peptide backbone unit (-CH(2)C=ONH-), and various functional groups from water to IL solutions. Our results explicitly elucidate that a series of all ammonium ILs act as stabilizers for tested model compounds through the exclusion of ILs from CDs surface.

  5. A simple and green pathway toward nitrogen and sulfur dual doped hierarchically porous carbons from ionic liquids for oxygen reduction

    NASA Astrophysics Data System (ADS)

    Cui, Zhentao; Wang, Shuguang; Zhang, Yihe; Cao, Minhua

    2014-08-01

    We for the first time demonstrate a simple and green approach to heteroatom (N and S) co-doped hierarchically porous carbons (N-S-HC) with high surface area by using one organic ionic liquid as nitrogen, sulfur and carbon sources and the eutectic salt as templating. The resultant dual-doped N-S-HC catalysts exhibit significantly enhanced electrocatalytic activity, long-term operation stability, and tolerance to crossover effect compared to commercial Pt/C for oxygen reduction reactions (ORR) in alkaline environment. The excellent electrocatalytic performance may be attributed to the synergistic effects, which includes more catalytic sites for ORR provided by N-S heteroatom doping and high electron transfer rate provided by hierarchically porous structure. The DFT calculations reveal that the dual doping of S and N atoms lead to the redistribution of spin and charge densities, which may be responsible for the formation of a large number of carbon atom active sites. This newly developed approach may supply an efficient platform for the synthesis of a series of heteroatom doped carbon materials for fuel cells and other applications.

  6. Catalytic Addition of Simple Alkenes to Carbonyl Compounds Using Group 10 Metals

    PubMed Central

    Schleicher, Kristin D.

    2011-01-01

    Recent advances using nickel complexes in the activation of unactivated monosubstituted olefins for catalytic intermolecular carbon–carbon bond-forming reactions with carbonyl compounds, such as simple aldehydes, isocyanates, and conjugated aldehydes and ketones, are discussed. In these reactions, the olefins function as vinyl- and allylmetal equivalents, providing a new strategy for organic synthesis. Current limitations and the outlook for this new strategy are also discussed. PMID:21904421

  7. Ionic Blocks

    ERIC Educational Resources Information Center

    Sevcik, Richard S.; Gamble, Rex; Martinez, Elizabet; Schultz, Linda D.; Alexander, Susan V.

    2008-01-01

    "Ionic Blocks" is a teaching tool designed to help middle school students visualize the concepts of ions, ionic compounds, and stoichiometry. It can also assist high school students in reviewing their subject mastery. Three dimensional blocks are used to represent cations and anions, with color indicating charge (positive or negative) and size…

  8. Effect of Eccentricity in Compound Droplets Subject to a Simple Shear Flow

    NASA Astrophysics Data System (ADS)

    Kim, Sangkyu; Dabiri, Sadegh

    2016-11-01

    A double emulsion, or a compound droplet, is a system where two liquids are separated by an immiscible third liquid, thereby forming an emulsion inside an emulsion. Compound drops benefit from this separation in applications such food sciences, microfluidics, pharmaceutical engineering, and polymer sciences. While the subjects of double emulsion preparations, deformations, and breakup mechanisms are well-explored, the time-evolution of non-concentric compound drops has received far less analytical or computational scrutiny. In this work, we present computational results using finite volume method with front-tracking approach for initially spherical and non-concentric compound drops in a shear flow. Our findings for low Reynolds number flows show that: 1. The surrounding shear flow to the outer drop induces a rotational velocity field inside it, causing the inner drop to tumble with the flow, 2. the tumbling motion persists in time, and acts to increase the eccentricity of the compound drop, and 3. the hemisection-plane to the outer drop that is aligned with the plane of the simple shear defines an unstable equilibrium for inner drop's center, and the inner drop continuously drifts away from that plane. This work suggests a means of favorably configuring compound drops suitable for breakups, and helps to understand their migration in channel flows.

  9. 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

    EPA Science Inventory

    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...

  10. Binding of alkyl- and alkoxy-substituted simple phenolic compounds to human serum proteins.

    PubMed

    Ogata, N; Shibata, T

    2000-01-01

    Wood creosote, primarily a mixture of simple alkyl- and/or alkoxy-substituted phenolic compounds with closely related structures, has long been used as an oral antidiarrheal agent. The use of wood creosote as a parenteral antidiarrheal agent was investigated, and for basic pharmacokinetic data we measured the extent of equilibrium binding of its six major constituent phenolic compounds to human serum proteins using an ultrafiltration method. The percent binding of these major constituent phenolic compounds, namely phenol, guaiacol, p-cresol, o-cresol, creosol and 4-ethylguaiacol, bound to 40-mg/ml human serum albumin was 15.5+/-0.9, 28.0+/-1.5, 37.2+/-0.7, 52.3+/-5.3, 36.8+/-2.0 and 56.7+/-2.4%, respectively, while percent binding to human serum (68 mg protein/ml) was 41.3+/-0.7, 42.6+/-0.5, 64.8+/-0.4, 70.1+/-1.6, 65.7+/-0.2 and 83.1+/-0.1% (mean +/- standard deviation, n = 4), respectively, when tested individually at a concentration of 500 micromol/l. Saturation of binding was not observed for the phenolic compounds up to a concentration of 50 mmol/l. Phenolic compounds with a lipophilic substituent showed higher percent binding to proteins than those without it. We conclude that simple phenolic compounds having alkyl- and/or alkoxy-substituents bind to serum proteins to a considerable extent and that the binding is hydrophobic and nonspecific.

  11. Investigation of ionic transport in sodium scandium phosphate (NSP) and related compounds

    NASA Astrophysics Data System (ADS)

    Bhat, Kaustubh; Blügel, Stefan; Lustfeld, Hans

    Sodium ionic conductors offer significant advantages for application in large scale energy storage systems. In this study, we investigate the different pathways available for sodium ion conduction in NSP and calculate energy barriers for ionic transport using Density Functional Theory (DFT) and the Nudged Elastic Band Method. We identify the structural parameters that reduce the energy barrier, by calculating the influence of positive and negative external pressure on the energy barrier. Lattice strain can be introduced by cation or anion substitution within the NASICON structure. We substitute the scandium atom with other trivalent atoms such as aluminium and yttrium, and calculate the resulting energy barriers. Sodium thiophosphate (Na3PS4) has previously shown about two orders of magnitude higher ionic conductivity than sodium phosphate (Na3PO4). We investigate the effect of substituting oxygen with sulphur in NSP. We acknowledge discussions with our experimental colleagues F. Tietz and M. Guin toward this work

  12. Partition Coefficients of Organic Compounds in New Imidazolium and Tetralkylammonium Based Ionic Liquids Using Inverse Gas Chromatography

    SciTech Connect

    Mutelet, Fabrice; Revelli, Anne-Laure; Jaubert, Jean-Noel; Sprunger, Laura; Acree, William; Baker, Gary A

    2010-01-01

    Partition coefficients of 51 organic compounds in two ionic liquids (IL), 1-ethyl-3-methylimidazolium dicyanamide and trimethylhexylammonium bis((trifluoromethyl)sulfonyl)amide, were measured using inverse gas chromatography from (322.5 to 352.5) K. These partition coefficients were converted into water-to-IL partition coefficients using the corresponding gas-to-water partition coefficients. Both sets of partition coefficients were analyzed using the Abraham solvation parameter model with cation-specific and anionspecific equation coefficients. The derived equations correlated the experimental gas-to-IL and water-to-IL partition coefficient data to within (0.12 and 0.14) log units, respectively.

  13. Generalization of ionic partition diagrams to lipophilic compounds and to biphasic systems with variable phase volume ratios.

    PubMed

    Gobry, V; Ulmeanu, S; Reymond, F; Bouchard, G; Carrupt, P A; Testa, B; Girault, H H

    2001-10-31

    The ionic partition diagram methodology has been generalized to address both hydrophilic and lipophilic compounds and to consider biphasic systems with variable phase volume ratios. With this generalized approach electrochemical measurements of ion transfer potentials afford the determination of the standard partition coefficients of all forms of ionizable molecules, including the neutral form, as well as the evaluation of the dissociation constant of monoprotic substances. An interesting consequence of this approach is the definition of an extraction pK(a,ext) which is the apparent pK(a) of neutral acids and bases when dissolved in the organic phase.

  14. A Simple and Universal Gel Permeation Chromatography Technique for Precise Molecular Weight Characterization of Well-Defined Poly(ionic liquid)s

    SciTech Connect

    He, Hongkun; Zhong, Mingjiang; Adzima, Brian; Luebke, David; Nulwala, Hunaid; Matyjaszewski, Krzysztof

    2013-03-20

    Poly(ionic liquid)s (PILs) are an important class of technologically relevant materials. However, characterization of well-defined polyionic materials remains a challenge. Herein, we have developed a simple and versatile gel permeation chromatography (GPC) methodology for molecular weight (MW) characterization of PILs with a variety of anions. PILs with narrow MW distributions were synthesized via atom transfer radical polymerization, and the MWs obtained from GPC were further confirmed via nuclear magnetic resonance end group analysis.

  15. The complex story of a simple Brønsted acid: unusual speciation of HBr in an ionic liquid medium.

    PubMed

    Driver, Gordon W; Mutikainen, Ilpo

    2011-11-07

    Crystalline solids, co-existing in equilibrium with the 3-methyl-1H-imidazolium bromohydrogenates(I) ionic liquid, have been characterised by X-ray diffraction analysis. The Brønsted acidic, homo-conjugate [H(2)Br(3)](-) anions presented are discussed in terms of their structure and reactivity, in efforts to advance the understanding of Brønsted acidity in ionic liquid media.

  16. Should Gaseous BF3 and SiF4 Be Described as Ionic Compounds?

    NASA Astrophysics Data System (ADS)

    Haaland, Arne; Helgaker, Trygve; Ruud, Kenneth; Shorokhov, D. J.

    2000-08-01

    The atomic charges in BF3 calculated by the "atoms in molecules" approach are +2.58 and -0.87 for B and F, respectively; in SiF4 the calculated charges are +3.42 and -0.86, and it has therefore been suggested that these molecules should be described as fully ionic (R. J. Gillespie, J. Chem. Educ. 1998, 75, 923). However, atomic charges calculated by an alternative approach (from the atomic polar tensors) are lower by more than 30%. Calculations based on a spherical ion model show that this model underestimates the mean bond energies of BF3 and SiF4 by more than 40%, and calculations based on a polarizable ion model indicate that the F- ions are considerably distorted in the direction of polar covalency. It is concluded, therefore, that a description in terms of a completely ionic model may be misleading.

  17. Formation of hybrid ABX3 perovskite compounds for solar cell application: first-principles calculations of effective ionic radii and determination of tolerance factors.

    PubMed

    Becker, Markus; Klüner, Thorsten; Wark, Michael

    2017-03-14

    The development of hybrid organic-inorganic perovskite solar cells is one of the most rapidly growing fields in the photovoltaic community and is on its way to challenge polycrystalline silicon and thin film technologies. High power conversion efficiencies can be achieved by simple processing with low cost. However, due to the limited long-term stability and environmental toxicity of lead in the prototypic CH3NH3PbI3, there is a need to find alternative ABX3 constitutional combinations in order to promote commercialization. The Goldschmidt tolerance factor and the octahedral factor were found to be necessary geometrical concepts to evaluate which perovskite compounds can be formed. It was figured out that the main challenge lies in estimating an effective ionic radius for the molecular cation. We calculated tolerance factors and octahedral factors for 486 ABX3 monoammonium-metal-halide combinations, where the steric size of the molecular cation in the A-position was estimated concerning the total charge density. A thorough inquiry about existing mixed organic-inorganic perovskites was undertaken. Our results are in excellent agreement with the reported hybrid compounds and indicate the potential existence of 106 ABX3 combinations hitherto not discussed in the literature, giving hints for more intense research on prospective individual candidates.

  18. Combined use of chiral ionic liquid surfactants and neutral cyclodextrins: Evaluation of ionic liquid head groups for enantioseparation of neutral compounds in capillary electrophoresis

    PubMed Central

    Liu, Yijin; Shamsi, Shahab A.

    2014-01-01

    Cyclodextrins (CDs) are most commonly used chiral selectors in capillary electrophoresis (CE). Although the use of neutral CDs and its derivatives have shown to resolve plethora of charged enantiomers, they cannot resolve neutral enantiomers. The use of ionic liquids (ILs) surfactants forming successful complex with CDs present itself an opportunity to resolve neutral enantiomers. In this work, the effect of IL head groups and their complexation ability with heptakis (2,3,6-tri-O-methyl)-β-cyclodextrin (TM-β-CD) was studied for the separation of neutral enantiomers by CE. First, cationic IL type surfactants with different chiral head groups were synthesized. Physicochemical properties such as critical micelle concentration was determined by surface tension, whereas aggregation and polarity were determined by fluorescence spectroscopy. The complexation ability of ILs with TM-β-CD was characterized in the gas phase by CE-mass spectrometry. The influence of the type of ILs head group and its concentration on chiral resolution, resolution per unit time and selectivity were investigated for four structurally diverse neutral compounds. The binding constants of the neutral analytes to the IL-CD complex were estimated by y-reciprocal method. The hydrophobicity of the side chain of the IL head group displayed significant effect on the binding constants and enantioseparations. PMID:25130088

  19. Structural basis for the enhanced stability of protein model compounds and peptide backbone unit in ammonium ionic liquids.

    PubMed

    Vasantha, T; Attri, Pankaj; Venkatesu, Pannuru; Devi, R S Rama

    2012-10-04

    Protein folding/unfolding is a fascinating study in the presence of cosolvents, which protect/disrupt the native structure of protein, respectively. The structure and stability of proteins and their functional groups may be modulated by the addition of cosolvents. Ionic liquids (ILs) are finding a vast array of applications as novel cosolvents for a wide variety of biochemical processes that include protein folding. Here, the systematic and quantitative apparent transfer free energies (ΔG'(tr)) of protein model compounds from water to ILs through solubility measurements as a function of IL concentration at 25 °C have been exploited to quantify and interpret biomolecular interactions between model compounds of glycine peptides (GPs) with ammonium based ILs. The investigated aqueous systems consist of zwitterionic glycine peptides: glycine (Gly), diglycine (Gly(2)), triglycine (Gly(3)), tetraglycine (Gly(4)), and cyclic glycylglycine (c(GG)) in the presence of six ILs such as diethylammonium acetate (DEAA), diethylammonium hydrogen sulfate (DEAS), triethylammonium acetate (TEAA), triethylammonium hydrogen sulfate (TEAS), triethylammonium dihydrogen phosphate (TEAP), and trimethylammonium acetate (TMAA). We have observed positive values of ΔG'(tr) for GPs from water to ILs, indicating that interactions between ILs and GPs are unfavorable, which leads to stabilization of the structure of model protein compounds. Moreover, our experimental data ΔG'(tr) is used to obtain transfer free energies (Δg'(tr)) of the peptide backbone unit (or glycyl unit) (-CH(2)C═ONH-), which is the most numerous group in globular proteins, from water to IL solutions. To obtain the mechanism events of the ILs' role in enhancing the stability of the model compounds, we have further obtained m-values for GPs from solubility limits. These results explicitly elucidate that all alkyl ammonium ILs act as stabilizers for model compounds through the exclusion of ILs from model compounds of

  20. Synthesis and toxicity evaluation of hydrophobic ionic liquids for volatile organic compounds biodegradation in a two-phase partitioning bioreactor.

    PubMed

    Rodriguez Castillo, Alfredo Santiago; Guihéneuf, Solène; Le Guével, Rémy; Biard, Pierre-François; Paquin, Ludovic; Amrane, Abdeltif; Couvert, Annabelle

    2016-04-15

    Synthesis of several hydrophobic ionic liquids (ILs), which might be selected as good candidates for degradation of hydrophobic volatile organic compounds in a two-phase partitioning bioreactor (TPPB), were carried out. Several bioassays were also realized, such as toxicity evaluation on activated sludge and zebrafish, cytotoxicity, fluoride release in aqueous phase and biodegradability in order to verify their possible effects in case of discharge in the aquatic environment and/or human contact during industrial manipulation. The synthesized compounds consist of alkylimidazoliums, functionalized imidazoliums, isoqinoliniums, triazoliums, sulfoniums, pyrrolidiniums and morpholiniums and various counter-ions such as: PF6(-), NTf2(-) and NfO(-). Toxicity evaluation on activated sludge of each compound (5% v/v of IL) was assessed by using a glucose uptake inhibition test. Toxicity against zebrafish and cytotoxicity were evaluated by the ImPACCell platform of Rennes (France). Fluoride release in water was estimated by regular measurements using ion chromatography equipment. IL biodegradability was determined by measuring BOD28 of aqueous samples (compound concentration,1mM). All ILs tested were not biodegradable; while some of them were toxic toward activated sludge. Isoquinolinium ILs were toxic to human cancerous cell lines. Nevertheless no toxicity was found against zebrafish Danio rerio. Only one IL released fluoride after long-time agitation.

  1. Highly Efficient Extraction of Phenolic Compounds by Use of Magnetic Room Temperature Ionic Liquids for Environmental Remediation

    PubMed Central

    Deng, Ning; Li, Min; Zhao, Lijie; Lu, Chengfei; de Rooy, Sergio L.; Warner, Isiah M.

    2011-01-01

    A hydrophobic magnetic room temperature ionic liquid (MRTIL), trihexyltetradecylphosphonium tetrachloroferrate(III) ([3C6PC14][FeCl4]), was synthesized from trihexyltetradecylphosphonium chloride and FeCl3·6H2O. This MRTIL was investigated as a possible separation agent for solvent extraction of phenolic compounds from aqueous solution. Due to its strong paramagnetism, [3C6PC14][FeCl4] responds to an external neodymium magnet, which was employed in the design of a novel magnetic extraction technique. The conditions for extraction, including extraction time, volume ratio between MRTIL and aqueous phase, pH of aqueous solution, and structures of phenolic compounds were investigated and optimized. The magnetic extraction of phenols achieved equilibrium in 20 min and the phenolic compounds were found to have higher distribution ratios under acidic conditions. In addition, it was observed that phenols containing a greater number of chlorine or nitro substitutents exhibited higher distribution ratios. For example, the distribution ratio of phenol (DPh) was 107. In contrast, 3,5-dichlorophenol distribution ratio (D3,5-DCP) had a much higher value of 6372 under identical extraction conditions. When compared with four selected traditional non-magnetic room temperature ionic liquids, our [3C6PC14][FeCl4] exhibited significantly higher extraction efficiency under the same experimental conditions used in this work. Pentachlorophenol, a major component in the contaminated soil sample obtained from a superfund site, was successfully extracted and removed by use of [3C6PC14][FeCl4] with high extraction efficiency. Pentachlorophenol concentration was dramatically reduced from 7.8 μg.mL−1 to 0.2 μg.mL−1 after the magnetic extraction by use of [3C6PC14][FeCl4]. PMID:21783320

  2. Exploring simple, transparent, interpretable and predictive QSAR models for classification and quantitative prediction of rat toxicity of ionic liquids using OECD recommended guidelines.

    PubMed

    Das, Rudra Narayan; Roy, Kunal; Popelier, Paul L A

    2015-11-01

    The present study explores the chemical attributes of diverse ionic liquids responsible for their cytotoxicity in a rat leukemia cell line (IPC-81) by developing predictive classification as well as regression-based mathematical models. Simple and interpretable descriptors derived from a two-dimensional representation of the chemical structures along with quantum topological molecular similarity indices have been used for model development, employing unambiguous modeling strategies that strictly obey the guidelines of the Organization for Economic Co-operation and Development (OECD) for quantitative structure-activity relationship (QSAR) analysis. The structure-toxicity relationships that emerged from both classification and regression-based models were in accordance with the findings of some previous studies. The models suggested that the cytotoxicity of ionic liquids is dependent on the cationic surfactant action, long alkyl side chains, cationic lipophilicity as well as aromaticity, the presence of a dialkylamino substituent at the 4-position of the pyridinium nucleus and a bulky anionic moiety. The models have been transparently presented in the form of equations, thus allowing their easy transferability in accordance with the OECD guidelines. The models have also been subjected to rigorous validation tests proving their predictive potential and can hence be used for designing novel and "greener" ionic liquids. The major strength of the present study lies in the use of a diverse and large dataset, use of simple reproducible descriptors and compliance with the OECD norms.

  3. Attenuation of 2-methoxyethanol-induced testicular toxicity in the rat by simple physiological compounds.

    PubMed

    Mebus, C A; Welsch, F; Working, P K

    1989-06-01

    2-Methoxyethanol (2-ME) is an industrial solvent which is toxic to both male and female reproductive systems of laboratory animals. Earlier data have demonstrated that the developmental toxicity of 2-ME can be attenuated by simple physiological compounds such as serine, acetate, sarcosine, glycine, and D-glucose. The present experiments were designed to evaluate the same compounds for their ability to ameliorate the testicular toxicity that occurs in rats after 2-ME exposure. The extent of testicular damage was assessed by quantitating daily sperm production (DSP) on Day 24 following a single dose of 2-ME (6.6 mmol/kg, 500 mg/kg). Serine completely eliminated 2-ME-induced decreases in DSP, while glucose was without effect. Acetate, sarcosine, and glycine were of similar efficacy resulting in DSP that was significantly greater than that observed in rats which received 2-ME alone. Histopathological studies revealed that 2-ME treatment resulted in stage-specific degeneration of late stage pachytene spermatocytes 24 hr after treatment. No apparent degenerative changes occurred after concurrent treatment with serine. Similarly, serine also prevented the decreased number of spermatids in the lumina of the seminiferous tubules on Day 24 after 2-ME exposure alone. All of the compounds utilized in this study are linked to oxidation pathways involving tetrahydrofolic acid as a catalyst for one-carbon moiety transfer into purine and pyrimidine bases which are necessary precursors for DNA and RNA synthesis. The ability of these compounds to attenuate the testicular toxicity of 2-ME may result from their ability to donate one-carbon units which can be used in purine base biosynthesis. Reduced availability of bases would be expected to affect late stage pachytene spermatocytes which are known to be undergoing rapid RNA synthesis.

  4. A novel and simple electrochemical sensor for electrocatalytic reduction of nitrite and oxidation of phenylhydrazine based on poly (o-anisidine) film using ionic liquid carbon paste electrode

    NASA Astrophysics Data System (ADS)

    Ojani, Reza; Raoof, Jahan-Bakhsh; Zamani, Saeed

    2013-04-01

    In this study, nitrite electroreduction and phenylhydrazine electrooxidation were investigated on poly(o-anisidine) formed by cyclic voltammetry at the surface of ionic liquid carbon paste electrode. The films were characterized by cyclic voltammetry and scanning electron microscopy (SEM) and were contrasted with poly(o-anisidine) prepared under identical conditions in the absence of ionic liquid in carbon paste electrode. This carbon paste modified electrode exhibits a good electrocatalytic capability (via an EC' mechanism) for both electrooxidation and electroreduction of some important molecules. The obtained results showed that the catalytic oxidation peak currents of phenylhydrazine and catalytic reduction peak currents of nitrite at the surface of this simple (unfunctionalized) polymeric electrode were linearly dependent on their concentrations. Electrode was successfully applied for determination of nitrite and phenylhydrazine in real samples.

  5. Preparation a new sorbent based on polymeric ionic liquid for stir cake sorptive extraction of organic compounds and inorganic anions.

    PubMed

    Huang, Xiaojia; Wang, Yulei; Hong, Qiuyun; Liu, Yi; Yuan, Dongxing

    2013-11-01

    A new multi-interaction sorbent (MIS) based on polymeric ionic liquid was prepared and used as extractive medium of stir cake sorptive extraction (SCSE). In the presence of dimethyl sulfoxide, an ionic liquid, 1-vinylbenzyl-3-methylimidazolium chloride was used as monomer to copolymerize in situ with divinylbenzene to form the MIS. The influences of the content of monomer and the porogen solvent in the polymerization mixture on the extraction performance were investigated thoroughly. The MIS was characterized by infrared spectroscopy, elemental analysis, scanning electron microscopy and mercury intrusion porosimetry. Parabens and aromatic amines were used to investigate the extraction performance of MIS-SCSE for apolar and strongly polar analytes, respectively. The extraction parameters for parabens and aromatic amines were optimized. At the same time, simple and sensitive analytical methods for parabens and aromatic amines in real samples were developed by the combination of MIS-SCSE and HPLC/DAD. Some inorganic anions, such as F(-), Br(-), NO3(-), PO4(3-) and SO4(2-), were used to test the extraction performance of MIS-SCSE for anions. Results indicated that mechanism involved in the extraction of MIS is the multi-interaction modes including π-π, hydrophobic, hydrogen-bonding, dipole-dipole and anion-exchange interactions.

  6. Fractionation of organosolv lignin from olive tree clippings and its valorization to simple phenolic compounds.

    PubMed

    Toledano, Ana; Serrano, Luis; Balu, Alina Mariana; Luque, Rafael; Pineda, Antonio; Labidi, Jalel

    2013-03-01

    Lignin valorization practices have attracted a great deal of interest in recent years due to the large excess of lignin produced by the pulp and paper industry, together with second-generation bioethanol plants. In this work, a new lignin valorization approach is proposed. It involves ultrafiltration as a fractionation process to separate different molecular weight lignin fractions followed by a hydrogen-free, mild, hydrogenolytic, heterogeneously catalyzed methodology assisted by microwave irradiation to obtain simple phenolic, monomeric products by depolymerization using a nickel-based catalyst. The main products obtained were desaspidinol, syringaldehyde, and syringol; this proves the efficiency of the depolymerization conditions applied. The concentration of these observed compounds increased when the molecular weights of the lignin fractions increased. The applied depolymerization conditions, which take advantage of the use of formic acid as a hydrogen-donating solvent, did not generate any biochar in the systems.

  7. Simple nanoparticle-based luminometric method for molecular weight determination of polymeric compounds.

    PubMed

    Pihlasalo, Sari; Virtamo, Maria; Legrand, Nicolas; Hänninen, Pekka; Härmä, Harri

    2014-01-21

    A nanoparticle-based method utilizing time-resolved luminescence resonance energy transfer (TR-LRET) was developed for molecular weight determination. This mix-and-measure nanoparticle method is based on the competitive adsorption between the analyte and the acceptor-labeled protein to donor Eu(III) nanoparticles. The size-dependent adsorption of molecules enables the molecular weight determination of differently sized polymeric compounds down to a concentration level of micrograms per liter. The molecular weight determination from 1 to 10 kDa for polyamino acids and from 0.3 to 70 kDa for polyethylene imines is demonstrated. The simple and cost-effective nanoparticle method as microtiter plate assay format shows great potential for the detection of the changes in molecular weight or for quantification of differently sized molecules in biochemical laboratories and in industrial polymeric processes.

  8. Chicken barn climate and hazardous volatile compounds control using simple linear regression and PID

    NASA Astrophysics Data System (ADS)

    Abdullah, A. H.; Bakar, M. A. A.; Shukor, S. A. A.; Saad, F. S. A.; Kamis, M. S.; Mustafa, M. H.; Khalid, N. S.

    2016-07-01

    The hazardous volatile compounds from chicken manure in chicken barn are potentially to be a health threat to the farm animals and workers. Ammonia (NH3) and hydrogen sulphide (H2S) produced in chicken barn are influenced by climate changes. The Electronic Nose (e-nose) is used for the barn's air, temperature and humidity data sampling. Simple Linear Regression is used to identify the correlation between temperature-humidity, humidity-ammonia and ammonia-hydrogen sulphide. MATLAB Simulink software was used for the sample data analysis using PID controller. Results shows that the performance of PID controller using the Ziegler-Nichols technique can improve the system controller to control climate in chicken barn.

  9. Application of pyroelectric crystal and ionic liquid to the production of metal compounds

    SciTech Connect

    Imashuku, Susumu; Imanishi, Akira; Kawai, Jun

    2013-04-19

    Zinc fluoride (ZnF{sub 2}) was deposited on a silicon substrate by changing temperature of a pyroelectric crystal of LiTaO{sub 3} on which ionic liquid (EMI-Tf{sub 2}N) containing zinc ions was dripped at 1 Pa. ZnF{sub 2} was also obtained by bombarding argon ions on EMI-Tf{sub 2}N containing zinc ions. From these results, it is concluded that EMI-Tf{sub 2}N containing zinc ions on the LiTaO{sub 3} crystal was evaporated on the silicon substrate by changing temperature of the LiTaO{sub 3} crystal in vacuum and that the evaporated EMI-Tf{sub 2}N containing metal zinc ions was decomposed to ZnF{sub 2} by the bombardment of electrons accelerated by the electric field between the LiTaO{sub 3} crystal and the silicon substrate.

  10. Platinum(II)-Oligonucleotide Coordination Based Aptasensor for Simple and Selective Detection of Platinum Compounds.

    PubMed

    Cai, Sheng; Tian, Xueke; Sun, Lianli; Hu, Haihong; Zheng, Shirui; Jiang, Huidi; Yu, Lushan; Zeng, Su

    2015-10-20

    Wide use of platinum-based chemotherapeutic regimens for the treatment for carcinoma calls for a simple and selective detection of platinum compound in biological samples. On the basis of the platinum(II)-base pair coordination, a novel type of aptameric platform for platinum detection has been introduced. This chemiluminescence (CL) aptasensor consists of a designed streptavidin (SA) aptamer sequence in which several base pairs were replaced by G-G mismatches. Only in the presence of platinum, coordination occurs between the platinum and G-G base pairs as opposed to the hydrogen-bonded G-C base pairs, which leads to SA aptamer sequence activation, resulting in their binding to SA coated magnetic beads. These Pt-DNA coordination events were monitored by a simple and direct luminol-peroxide CL reaction through horseradish peroxidase (HRP) catalysis with a strong chemiluminescence emission. The validated ranges of quantification were 0.12-240 μM with a limit of detection of 60 nM and selectivity over other metal ions. This assay was also successfully used in urine sample determination. It will be a promising candidate for the detection of platinum in biomedical and environmental samples.

  11. Is compound chaining the serial-order mechanism of spelling? A simple recurrent network investigation.

    PubMed

    Goldberg, Ariel M; Rapp, Brenda

    2008-03-01

    Although considerable progress has been made in determining the cognitive architecture of spelling, less is known about the serial-order mechanism of spelling: the process(es) involved in producing each letter in the proper order. In this study, we investigate compound chaining as a theory of the serial-order mechanism of spelling. Chaining theories posit that the retrieval from memory of each element in a sequence is dependent upon the retrieval of previous elements. We examine this issue by comparing the performance of simple recurrent networks (a class of neural networks that we show can operate by chaining) with that of two individuals with acquired dysgraphia affecting the serial-order mechanism of spelling-the graphemic buffer. We compare their performance in terms of the effects of serial position, the effect of length on overall letter accuracy, and the effect of length on the accuracy of specific positions within the word. We find that the networks produce significantly different patterns of performance from those of the dysgraphics, indicating that compound chaining is not an appropriate theory of the serial-order mechanism of spelling.

  12. CADDIS Volume 2. Sources, Stressors and Responses: Ionic Strength

    EPA Pesticide Factsheets

    Introduction to the ionic strength module, when to list ionic strength as a candidate cause, ways to measure ionic strength, simple and detailed conceptual diagrams for ionic strength, ionic strength module references and literature reviews.

  13. Constitutive knox1 gene expression in dandelion (Taraxacum officinale, Web.) changes leaf morphology from simple to compound.

    PubMed

    Müller, Kai J; He, Xinqiang; Fischer, Rainer; Prüfer, Dirk

    2006-10-01

    Seed plants with compound leaves constitute a polyphyletic group, but studies of diverse taxa show that genes of the class 1 KNOTTED-LIKE HOMEOBOX (KNOX1) family are often involved in compound leaf development. This suggests that knox1 genes have been recruited on multiple occasions during angiosperm evolution (Bharathan et al. in Science 296:1858-1860, 2002). In agreement with this, we demonstrate that the simple leaf of dandelion (Taraxacum officinale Web.) can be converted into a compound leaf by the constitutive expression of heterologous knox1 genes. Dandelion is a rosette plant of the family Asteraceae, characterised by simple leaves with deeply lobed margins and endogenous knox1 gene expression. Transgenic dandelion plants constitutively expressing the barley (Hordeum vulgare L.) hooded gene (bkn3, barley knox3) or the related bkn1 gene, developed compound leaves featuring epiphyllous rosettes. We discuss these results in the context of two current models of compound leaf formation.

  14. A simple guiding principle for the temperature dependence of the solubility of light gases in imidazolium-based ionic liquids derived from molecular simulations.

    PubMed

    Kerlé, Daniela; Namayandeh Jorabchi, Majid; Ludwig, Ralf; Wohlrab, Sebastian; Paschek, Dietmar

    2017-01-18

    We have determined the temperature dependence of the solvation behavior of a large collection of important light gases in imidazolium-based ionic liquids with the help of extensive molecular dynamics simulations. The motivation of our study is to unravel common features of the temperature dependent solvation under well controlled conditions, and to provide a guidance for cases, where experimental data from different sources disagree significantly. The solubility of molecular hydrogen, oxygen, nitrogen, methane, krypton, argon, neon and carbon dioxide in the imidazolium based ionic liquids of type 1-n-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Cnmim][NTf2]) with varying alkyl side chain lengths n = 2, 4, 6, 8 is computed for a temperature range between 300 K and 500 K at 1 bar. By applying Widom's particle insertion technique and Bennet's overlapping distribution method, we are able to determine the temperature dependent solvation free energies of those selected light gases in simulated imidazolium based ionic liquids with high statistical accuracy. Our simulations demonstrate that the magnitude of the solvation free energy of a gas molecule at a chosen reference temperature and that of its temperature-derivatives are intimately related to one another. We conclude that this "universal" behavior is rooted in a solvation entropy-enthalpy compensation effect, which seems to be a defining feature of the solvation of small molecules in ionic liquids. The observations lead to simple analytical relations, determining the temperature dependence of the solubility data based on the absolute solubility at a certain reference temperature. By comparing our results with available experimental data from many sources, we can show that our approach is particularly helpful for providing reliable estimates for the solvation behavior of very light gases, such as hydrogen, where conflicting experimental data exist.

  15. Simple and Rapid Method To Determine Antimycobacterial Potency of Compounds by Using Autoluminescent Mycobacterium tuberculosis

    PubMed Central

    Sharma, Sreevalli; Gelman, Ekaterina; Narayan, Chandan; Bhattacharjee, Deepa; Achar, Vijayashree; Humnabadkar, Vaishali; Balasubramanian, V.; Ramachandran, Vasanthi

    2014-01-01

    A major obstacle in the process of discovery of drugs against Mycobacterium tuberculosis is its extremely slow growth rate and long generation time (∼20 to 24 h). Consequently, determination of MICs and minimum bactericidal concentrations (MBCs) of potential drug candidates using current methods requires 7 days (resazurin-based MIC assay [REMA]) and 1 month (CFU enumeration), respectively. We employed a synthetic luciferase operon optimized for expression in high-GC-content bacteria and adapted it for use in mycobacteria. Using luminescence-based readouts, we were able to determine the MICs and bactericidal activities of approved tuberculosis (TB) drugs, which correlated well with currently used methods. Although luminescence-based readouts have been used previously to determine the MICs and bactericidal activities of approved TB drugs, in this study we adapted this assay to carry out a pilot screen using a library of 1,114 compounds belonging to diverse chemical scaffolds. We found that MICs derived from a 3-day luminescence assay matched well with REMA-based MIC values. To determine the bactericidal potencies of compounds, a 1:10 dilution of the cultures from the MIC plate was carried out on day 7, and the bactericidal concentrations determined based on time to positivity in 2 weeks were found to be comparable with MBC values determined by the conventional CFU approach. Thus, the luminescent mycobacterium-based approach not only is very simple and inexpensive but also allowed us to generate the information in half the time required by conventional methods. PMID:25049243

  16. Biologically Relevant Mechanism For Catalytic Removal of Superoxide by Simple Manganese Compounds

    SciTech Connect

    Barnese K.; Cabelli D.; Gralla, E.B.; Valentine, J.S.

    2012-05-01

    Nonenzymatic manganese was first shown to provide protection against superoxide toxicity in vivo in 1981, but the chemical mechanism responsible for this protection subsequently became controversial due to conflicting reports concerning the ability of Mn to catalyze superoxide disproportionation in vitro. In a recent communication, we reported that low concentrations of a simple Mn phosphate salt under physiologically relevant conditions will indeed catalyze superoxide disproportionation in vitro. We report now that two of the four Mn complexes that are expected to be most abundant in vivo, Mn phosphate and Mn carbonate, can catalyze superoxide disproportionation at physiologically relevant concentrations and pH, whereas Mn pyrophosphate and citrate complexes cannot. Additionally, the chemical mechanisms of these reactions have been studied in detail, and the rates of reactions of the catalytic removal of superoxide by Mn phosphate and carbonate have been modeled. Physiologically relevant concentrations of these compounds were found to be sufficient to mimic an effective concentration of enzymatic superoxide dismutase found in vivo. This mechanism provides a likely explanation as to how Mn combats superoxide stress in cellular systems.

  17. Enhancement of intestinal absorption of poorly absorbed hydrophilic compounds by simultaneous use of mucolytic agent and non-ionic surfactant.

    PubMed

    Takatsuka, Shinya; Kitazawa, Takeo; Morita, Takahiro; Horikiri, Yuji; Yoshino, Hiroyuki

    2006-01-01

    The effect of co-administration of a mucolytic agent with a penetration enhancer was assessed on the intestinal absorption of poorly absorbed hydrophilic compounds. Fluorescein isothiocyanate-labeled dextran with average molecular weight of ca. 4.4 kDa (FD-4) was used as a model compound, and N-acetylcysteine (NAC) was used as a mucolytic agent. Sodium caprate (C10), tartaric acid (TA), sodium taurodeoxycholate (TDC), sodium dodecyl sulfate (SDS), p-t-octyl phenol polyoxyethylene-9.5 (Triton X-100, TX-100) were selected as penetration enhancers with different mechanisms of action. Various dosing solutions containing a penetration enhancer in the absence or in the presence of NAC were directly administered into the exposed rat jejunum, and the bioavailability of FD-4 up to 2 h was determined. The extent of improvement by co-administration was highly dependent on the penetration enhancer species applied. The observed enhancement was thought to result from the mucolytic activity of NAC, which can reduce the mucus viscosity and facilitate the penetration of FD-4 to mucosal membrane. Among the combinations tested, the simultaneous administration of NAC and TX-100 provided the highest enhancement (22.5-fold) of intestinal FD-4 absorption compared to the control. Although the detailed mechanism for the observed drastic improvement is unclear, one possible reason was thought to be due to the improved diffusivity of TX-100 micellar system in the mucus layer. All these results suggest that the combination of a mucolytic agent and a non-ionic surfactant may have potential as an enhancing system for peroral delivery of poorly absorbed hydrophilic compounds like protein and peptide drugs.

  18. Ionic ac and dc conductivities of NaCrP2O7 compound

    NASA Astrophysics Data System (ADS)

    Sassi, M.; Oueslati, A.; Gargouri, M.

    2015-05-01

    The NaCrP2O7 compound was prepared by the solid-state reaction method. The formation of a single-phase material was confirmed by the X-ray diffraction studies and found to be a monoclinic system. The electrical properties of this compound have been measured in the temperature range from 523 to 673 K and the frequency range from 209 Hz to 5 MHz. The Nyquist plots are well fitted to an equivalent circuit consisting of a series of combination of grains and grain boundary elements. The ac conductivity of NaCrP2O7 has been analyzed as a function of temperature and frequency. The scaling behavior of the imaginary part of the complex modulus suggests that the relaxation describes the same mechanism at various temperatures. The conductivity and modulus formalisms provide nearly the same activation energies for electrical relaxation of mobile ions suggesting that the ion transport is probably due to a hopping mechanism dominated by the motion of the monovalent ions Na+ along tunnels presented in the structure of the investigated material.

  19. Azole-Anion-Based Aprotic Ionic Liquids: Functional Solvents for Atmospheric CO2 Transformation into Various Heterocyclic Compounds.

    PubMed

    Zhao, Yanfei; Wu, Yunyan; Yuan, Guangfeng; Hao, Leiduan; Gao, Xiang; Yang, Zhenzhen; Yu, Bo; Zhang, Hongye; Liu, Zhimin

    2016-10-06

    The chemical transformation of atmospheric CO2 is of great significance yet still poses a great challenge. Herein, azole-anion-based aprotic ionic liquids (ILs) were synthesized by the deprotonation of weak proton donors (e.g., 2-methylimidazole, 4-methylimidazole, and 2,4-dimethylimidazole) with tetrabutylphosphonium hydroxide, [Bu4 P][OH]. We found that these ILs, such as [Bu4 P][2-MIm], could activate atmospheric CO2 through the formation of carbamates. The resultant carbamate intermediates could further react with various types of substrate, including propargylic alcohols, 2-aminobenzonitriles, ortho-phenylenediamines, and 2-aminothiophenol, thereby producing α-alkylidene cyclic carbonates, quinazoline-2,4(1 H,3 H)-diones, benzimidazolones, and benzothiazoline, respectively, in moderate-to-good yields. Thus, we have achieved the transformation of CO2 at atmospheric pressure, and we expect this method to open up new routes for the synthesis of various oxygen-containing heterocyclic compounds under metal-free conditions.

  20. Determination of quaternary ammonium compounds by potentiometric titration with an ionic surfactant electrode: single-laboratory validation.

    PubMed

    Price, Randi; Wan, Ping

    2010-01-01

    A potentiometric titration for determining the quaternary ammonium compounds (QAC) commonly found in antimicrobial products was validated by a single laboratory. Traditionally, QACs were determined by using a biphasic (chloroform and water) manual titration procedure. Because of safety considerations regarding chloroform, as well as the subjectivity of color indicator-based manual titration determinations, an automatic potentiometric titration procedure was tested with quaternary nitrogen product formulations. By using the Metrohm Titrando system coupled with an ionic surfactant electrode and an Ag/AgCl reference electrode, titrations were performed with various QAC-containing formulation products/matrixes; a standard sodium lauryl sulfate solution was used as the titrant. Results for the products tested are sufficiently reproducible and accurate for the purpose of regulatory product enforcement. The robustness of the method was measured by varying pH levels, as well as by comparing buffered versus unbuffered titration systems. A quantitation range of 1-1000 ppm quaternary nitrogen was established. Eight commercially available antimicrobial products covering a variety of matrixes were assayed; the results obtained were comparable to those obtained by the manual titration method. Recoveries of 94 to 104% were obtained for spiked samples.

  1. Compound-class specific estimation of solid organic compound vapour pressure and aqueous solubility from simple molecular structure descriptors and the temperature of melting.

    PubMed

    van Noort, Paul C M

    2009-10-01

    For many solid organic compounds, experimental data for their aqueous solubility and vapour pressure are lacking. Therefore, estimation procedures for these compound properties are needed. On theoretical grounds, this study derives a general compound-class specific estimation procedure for solid organic compound aqueous solubility and vapour pressure. The estimation procedure uses a linear combination of simple molecular descriptors for the molecular structure variation within the compound class and a polynomial for the temperature of melting. This procedure is applied to the vapour pressure of polycyclic aromatic hydrocarbons (PAHs), alkylated PAHs, polychlorinated dibenzo-p-dioxins and biphenyls and to the aqueous solubility of PAHs, methylated PAHs, chlorinated benzenes, polychlorinated and polybrominated biphenyls, chlorinated phenols, cresols, and chlorinated 2-methoxyphenols. The standard error of the solid vapour pressure or aqueous solubility estimates from the various compound-class specific regression equations was about 0.2 log units. For PAHs, chlorobenzenes, and PCBs used in the present study, aqueous solubility estimated from the regression equations taking the temperature of melting equal to 298 K, i.e. assuming that the compounds are in a hypothetical liquid state, was equal, within 0.1-0.3 log units to the subcooled liquid solubility estimated from literature regression equations.

  2. Weighted Feature Significance: A Simple, Interpretable Model of Compound Toxicity Based on the Statistical Enrichment of Structural Features

    PubMed Central

    Huang, Ruili; Southall, Noel; Xia, Menghang; Cho, Ming-Hsuang; Jadhav, Ajit; Nguyen, Dac-Trung; Inglese, James; Tice, Raymond R.; Austin, Christopher P.

    2009-01-01

    In support of the U.S. Tox21 program, we have developed a simple and chemically intuitive model we call weighted feature significance (WFS) to predict the toxicological activity of compounds, based on the statistical enrichment of structural features in toxic compounds. We trained and tested the model on the following: (1) data from quantitative high–throughput screening cytotoxicity and caspase activation assays conducted at the National Institutes of Health Chemical Genomics Center, (2) data from Salmonella typhimurium reverse mutagenicity assays conducted by the U.S. National Toxicology Program, and (3) hepatotoxicity data published in the Registry of Toxic Effects of Chemical Substances. Enrichments of structural features in toxic compounds are evaluated for their statistical significance and compiled into a simple additive model of toxicity and then used to score new compounds for potential toxicity. The predictive power of the model for cytotoxicity was validated using an independent set of compounds from the U.S. Environmental Protection Agency tested also at the National Institutes of Health Chemical Genomics Center. We compared the performance of our WFS approach with classical classification methods such as Naive Bayesian clustering and support vector machines. In most test cases, WFS showed similar or slightly better predictive power, especially in the prediction of hepatotoxic compounds, where WFS appeared to have the best performance among the three methods. The new algorithm has the important advantages of simplicity, power, interpretability, and ease of implementation. PMID:19805409

  3. A New Fast and Simple Border Molding Process for Complete Dentures Using a Compound Stick Gun.

    PubMed

    Park, Chan; Yang, Hong-So; Lim, Hyun-Pil; Yun, Kwi-Dug; Oh, Gye-Jeong; Park, Sang-Won

    This article describes the use of a newly invented compound stick gun to take impressions for complete denture. The border molding process involves loading the modeling compound in an electric heating device and applying an even thickness of compound on the flange of a custom tray at a proper temperature without hot water tempering. This method provides a quicker and easier border molding process alternative to conventional techniques.

  4. Quantitative Analysis of Organic Compounds: A Simple and Rapid Method for Use in Schools

    ERIC Educational Resources Information Center

    Schmidt, Hans-Jurgen

    1973-01-01

    Describes the procedure for making a quantitative analysis of organic compounds suitable for secondary school chemistry classes. Using the Schoniger procedure, the organic compound, such as PVC, is decomposed in a conical flask with oxygen. The products are absorbed in a suitable liquid and analyzed by titration. (JR)

  5. Defining the limits of flowers: the challenge of distinguishing between the evolutionary products of simple versus compound strobili

    PubMed Central

    Rudall, Paula J.; Bateman, Richard M.

    2010-01-01

    Recent phylogenetic reconstructions suggest that axially condensed flower-like structures evolved iteratively in seed plants from either simple or compound strobili. The simple-strobilus model of flower evolution, widely applied to the angiosperm flower, interprets the inflorescence as a compound strobilus. The conifer cone and the gnetalean ‘flower’ are commonly interpreted as having evolved from a compound strobilus by extreme condensation and (at least in the case of male conifer cones) elimination of some structures present in the presumed ancestral compound strobilus. These two hypotheses have profoundly different implications for reconstructing the evolution of developmental genetic mechanisms in seed plants. If different flower-like structures evolved independently, there should intuitively be little commonality of patterning genes. However, reproductive units of some early-divergent angiosperms, including the extant genus Trithuria (Hydatellaceae) and the extinct genus Archaefructus (Archaefructaceae), apparently combine features considered typical of flowers and inflorescences. We re-evaluate several disparate strands of comparative data to explore whether flower-like structures could have arisen by co-option of flower-expressed patterning genes into independently evolved condensed inflorescences, or vice versa. We discuss the evolution of the inflorescence in both gymnosperms and angiosperms, emphasising the roles of heterotopy in dictating gender expression and heterochrony in permitting internodal compression. PMID:20047867

  6. A Simple Demonstration of the Curie-Weiss Law and a Spin-Crossover Compound.

    ERIC Educational Resources Information Center

    Hutchinson, Bennett; And Others

    1980-01-01

    Discusses an addition to an apparatus which allows the effect of temperature on a paramagnetic compound to be measured, therefore demonstrating the Curie-Weiss law. The experiment can be used as a demonstration or student experiment to stimulate discussion of magnetic susceptibility and ligand field trips. (Author/JN)

  7. A simple method for screening antimicrobial compounds with application to horticultural crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It is often difficult to extrapolate information obtained under laboratory conditions to the field. This is especially true in the case of translating reactions between microorganisms grown in a Petri dish with experimental antimicrobials, and using these experimental compounds in commercial applic...

  8. CADDIS Volume 2. Sources, Stressors and Responses: Ionic Strength - Detailed Conceptual Diagram

    EPA Pesticide Factsheets

    Introduction to the ionic strength module, when to list ionic strength as a candidate cause, ways to measure ionic strength, simple and detailed conceptual diagrams for ionic strength, ionic strength module references and literature reviews.

  9. Correlative Multimodal Probing of Ionically-Mediated Electromechanical Phenomena in Simple Oxides: Reversible and Irreversible Electrochemical Processes in NiO

    SciTech Connect

    Kim, Yunseok; Strelcov, Evgheni; Hwang, In Rok; Choi, Taekjib; Park, Bae Ho; Jesse, Stephen; Kalinin, Sergei V

    2013-01-01

    The interplay between the ionic and electronic transport in NiO is explored on the nanoscale using correlative imaging by first-order reversal curve measurements in current-voltage and electrochemical strain microscopy. Electronic current and electromechanical response are observed in reversible and electroforming regime. These studies provide insight into nanoscale mechanisms of electroresistive phenomena in NiO and establish universal method to study interplay between the ionic and electronic transport and electrochemical transformations in mixed electronic-ionic conductors.

  10. Enhanced super-hydrophobic and switching behavior of ZnO nanostructured surfaces prepared by simple solution--immersion successive ionic layer adsorption and reaction process.

    PubMed

    Suresh Kumar, P; Sundaramurthy, J; Mangalaraj, D; Nataraj, D; Rajarathnam, D; Srinivasan, M P

    2011-11-01

    A simple and cost-effective successive ionic layer adsorption and reaction (SILAR) method was adopted to fabricate hydrophobic ZnO nanostructured surfaces on transparent indium-tin oxide (ITO), glass and polyethylene terephthalate (PET) substrates. ZnO films deposited on different substrates show hierarchical structures like spindle, flower and spherical shape with diameters ranging from 30 to 300 nm. The photo-induced switching behaviors of ZnO film surfaces between hydrophobic and hydrophilic states were examined by water contact angle and X-ray photoelectron spectroscopy (XPS) analysis. ZnO nanostructured films had contact angles of ~140° and 160°±2 on glass and PET substrates, respectively, exhibiting hydrophobic behavior without any surface modification or treatment. Upon exposure to ultraviolet (UV) illumination, the films showed hydrophilic behavior (contact angle: 15°±2), which upon low thermal stimuli revert back to its original hydrophobic nature. Such reversible and repeatable switching behaviors were observed upon cyclical exposure to ultraviolet radiation. These biomimetic ZnO surfaces exhibit good anti-reflective properties with lower reflectance of 9% for PET substrates. Thus, the present work is significant in terms of its potential application in switching devices, solar coatings and self-cleaning smart windows.

  11. Multiple functional ionic liquids based dispersive liquid-liquid microextraction combined with high performance chromatography for the determination of phenolic compounds in water samples.

    PubMed

    Sun, Jian-Nan; Chen, Juan; Shi, Yan-Ping

    2014-07-01

    A new mode of ionic liquid based dispersive liquid-liquid microextraction (IL-DLLME) is developed. In this work, [C6MIm][PF6] was chosen as the extraction solvent, and two kinds of hydrophilic ionic liquids, [EMIm][BF4] and [BSO3HMIm][OTf], functioned as the dispersive solvent. So in the whole extraction procedure, no organic solvent was used. With the aid of SO3H group, the acidic compound was extracted from the sample solution without pH adjustment. Two phenolic compounds, namely, 2-naphthol and 4-nitrophenol were chosen as the target analytes. Important parameters affecting the extraction efficiency, such as the type of hydrophilic ionic liquids, the volume ratio of [EMIm][BF4] to [BSO3HMIm][OTf], type and volume of extraction solvent, pH value of sample solution, sonication time, extraction time and centrifugation time were investigated and optimized. Under the optimized extraction conditions, the method exhibited good sensitivity with the limits of detection (LODs) at 5.5 μg L(-1)and 10.0 μg L(-1) for 4-nitrophenol and 2-naphthol, respectively. Good linearity over the concentration ranges of 24-384 μg L(-1) for 4-nitrophenol and 28-336 μg L(-1) for 2-naphthol was obtained with correlation coefficients of 0.9998 and 0.9961, respectively. The proposed method can directly extract acidic compound from environmental sample or even more complex sample matrix without any pH adjustment procedure.

  12. Waveform Similarity Analysis: A Simple Template Comparing Approach for Detecting and Quantifying Noisy Evoked Compound Action Potentials.

    PubMed

    Potas, Jason Robert; de Castro, Newton Gonçalves; Maddess, Ted; de Souza, Marcio Nogueira

    2015-01-01

    Experimental electrophysiological assessment of evoked responses from regenerating nerves is challenging due to the typical complex response of events dispersed over various latencies and poor signal-to-noise ratio. Our objective was to automate the detection of compound action potential events and derive their latencies and magnitudes using a simple cross-correlation template comparison approach. For this, we developed an algorithm called Waveform Similarity Analysis. To test the algorithm, challenging signals were generated in vivo by stimulating sural and sciatic nerves, whilst recording evoked potentials at the sciatic nerve and tibialis anterior muscle, respectively, in animals recovering from sciatic nerve transection. Our template for the algorithm was generated based on responses evoked from the intact side. We also simulated noisy signals and examined the output of the Waveform Similarity Analysis algorithm with imperfect templates. Signals were detected and quantified using Waveform Similarity Analysis, which was compared to event detection, latency and magnitude measurements of the same signals performed by a trained observer, a process we called Trained Eye Analysis. The Waveform Similarity Analysis algorithm could successfully detect and quantify simple or complex responses from nerve and muscle compound action potentials of intact or regenerated nerves. Incorrectly specifying the template outperformed Trained Eye Analysis for predicting signal amplitude, but produced consistent latency errors for the simulated signals examined. Compared to the trained eye, Waveform Similarity Analysis is automatic, objective, does not rely on the observer to identify and/or measure peaks, and can detect small clustered events even when signal-to-noise ratio is poor. Waveform Similarity Analysis provides a simple, reliable and convenient approach to quantify latencies and magnitudes of complex waveforms and therefore serves as a useful tool for studying evoked compound

  13. Simple ortho- and para-hydroquinones as compounds neuroprotective against oxidative stress in a manner associated with specific transcriptional activation

    SciTech Connect

    Satoh, Takumi Saitoh, Sachie; Hosaka, Manami; Kosaka, Kunio

    2009-02-06

    Electrophilic compounds protect neurons through the activation of the Keap1/Nrf2 pathway and the induction of phase-2 enzymes [T. Satoh, S.A. Lipton, Redox regulation of neuronal survival by electrophilic compounds, Trends Neurosci. 30 (2007) 38-45; T. Satoh, S. Okamoto, J. Cui, Y. Watanabe, K. Furuta, M. Suzuki, K. Tohyama, S.A. Lipton, Activation of the Keap1/Nrf2 pathway for neuroprotection by electrophilic phase II inducers. Proc. Natl. Acad. Sci. USA 103 (2006) 768-773]. Hydroquinone-type electrophilic compounds such as tert-butyl hydroquinone (TBHQ) and carnosic acid (CA) have attracted special attention, because the oxidative conversion of 'hydroquinone' to 'quinone' is essential for the transcriptional activation of the above-mentioned enzymes [T. Satoh, K. Kosaka, K. Itoh, A. Kobayashi, M. Yamamoto, Y. Shimojo, C. Kitajima, J. Cui, J. Kamins, S. Okamoto, T. Shirasawa, S.A. Lipton, Carnosic acid, a catechol-type electrophilic compound, protect neurons both in vitro and in vivo through activation of the Keap1/Nrf2 pathway via S-alkylation of specific cysteine, J. Neurochem. 104 (2008) 1161-1131; A.D. Kraft, D.A. Johnson, J.A. Johnson, Nuclear factor E2-related factor 2-dependent antioxidant response element activation by tert-butylhydroquinone and sulforaphane occurring preferentially in astrocytes conditions neurons against oxidative insult, J. Neurosci. 24 (2004) 1101-1112]. In the present study, we examined the relationship between electrophilicity and the protective effects afforded by electrophilic compounds. Electrophilicity was assessed in terms of the ability of a compound to bind to a cysteine on bovine serum albumin, by which we found that neuroprotective hydroquinones [TBHQ (para-) and CA (ortho-)] had distinctive patterns of cysteine binding compared with other electrophilic compounds. Further, we found that isomers of simple ortho- and para-hydroquinones such as 2-methylhydroquinone (para-) and 4-methyl-catechol (ortho-) [not in abstract] had

  14. Cyclic voltammetry using silver as cathode material: a simple method for determining electro and chemical features and solubility values of CO2 in ionic liquids.

    PubMed

    Reche, Irene; Gallardo, Iluminada; Guirado, Gonzalo

    2015-01-28

    A report is presented on the use of cyclic voltammetry using silver as a working electrode. The combined electrocatalytic properties of silver and ionic liquids allow cyclic voltammetry to be turned into an ideal tool for the rapid and accurate access to diffusion coefficient values and solubility values of carbon dioxide in ionic liquids under standard conditions.

  15. Heat Transfer, Adiabatic Effectiveness and Injectant Distributions Downstream of Single Rows and Two Staggered Rows of Film-Cooling Holes with Simple and Compound Angles

    DTIC Science & Technology

    1991-12-01

    ROWS AND TWO STAGGERED ROWS OF FILM-COOLING HOLES WITH SIMPLE AND COMPOUND ANGLES 92-01241 by DIII l, p111111~ 11I Stephen Mark Jackson DECEMBER 1991...HOLES WITH SIMPLE AND COMPOUND ANGLES 12. PERSONAL AUTHORS STEPHEN MARK JACKSON 13a TYPE OF REPORT 13b TIME COVERED 14. DATE OF REPORT (Year. A4int, Day...Rows of Film-Cooling Holes with Simple and Compound Angles by Stephen Mark Jackson lieutenant, United States Navy B.S., United States Naval Academy, 1983

  16. Simple determination of a strongly aromatic compound, sotolon, by capillary electrophoresis.

    PubMed

    Taga, Atsushi; Sato, Atsushi; Suzuki, Kentaro; Takeda, Manami; Kodama, Shuji

    2012-01-01

    A strongly aromatic compound, sotolon, was assessed by capillary zone electrophoresis within 9 min without specific pre-sample treatment. The calibration curve comprised a straight line with good linearity (R = 0.997) over a relatively wide range of 3.13 to 100 ppm. The precision of this system was excellent with relative standard deviations of 1.39% for migration time and 2.96 % for peak response over 10 repetitions at a concentration of 12.5 ppm. The limit of quantitation and limit of detection values were 3.13 ppm (S/N = 9) and 0.781 ppm (S/N = 3), respectively. Using this system, sotolon was clearly detected from a maple-flavored food additive.

  17. Predicting the partitioning of biological compounds between room-temperature ionic liquids and water by means of the solvation-parameter model.

    PubMed

    Padró, Juan M; Ponzinibbio, Agustín; Mesa, Leidy B Agudelo; Reta, Mario

    2011-03-01

    The partition coefficients, P(IL/w), for different probe molecules as well as for compounds of biological interest between the room-temperature ionic liquids (RTILs) 1-butyl-3-methylimidazolium hexafluorophosphate, [BMIM][PF(6)], 1-hexyl-3-methylimidazolium hexafluorophosphate, [HMIM][PF(6)], 1-octyl-3-methylimidazolium tetrafluoroborate, [OMIM][BF(4)] and water were accurately measured. [BMIM][PF(6)] and [OMIM][BF(4)] were synthesized by adapting a procedure from the literature to a simpler, single-vessel and faster methodology, with a much lesser consumption of organic solvent. We employed the solvation-parameter model to elucidate the general chemical interactions involved in RTIL/water partitioning. With this purpose, we have selected different solute descriptor parameters that measure polarity, polarizability, hydrogen-bond-donor and hydrogen-bond-acceptor interactions, and cavity formation for a set of specifically selected probe molecules (the training set). The obtained multiparametric equations were used to predict the partition coefficients for compounds not present in the training set (the test set), most being of biological interest. Partial solubility of the ionic liquid in water (and water into the ionic liquid) was taken into account to explain the obtained results. This fact has not been deeply considered up to date. Solute descriptors were obtained from the literature, when available, or else calculated through commercial software. An excellent agreement between calculated and experimental log P(IL/w) values was obtained, which demonstrated that the resulting multiparametric equations are robust and allow predicting partitioning for any organic molecule in the biphasic systems studied.

  18. Phase Transition Enthalpy Measurements of Organic and Organometallic Compounds and Ionic Liquids. Sublimation, Vaporization, and Fusion Enthalpies from 1880 to 2015. Part 2. C11-C192

    NASA Astrophysics Data System (ADS)

    Acree, William; Chickos, James S.

    2017-03-01

    The second part of this compendium concludes with a collection of phase change enthalpies of organic molecules inclusive of C11-C192 reported over the period 1880-2015. Also included are phase change enthalpies including fusion, vaporization, and sublimation enthalpies for organometallic, ionic liquids, and a few inorganic compounds. Paper I of this compendium, published separately, includes organic compounds from C1 to C10 and describes a group additivity method for evaluating solid, liquid, and gas phase heat capacities as well as temperature adjustments of phase changes. Paper II of this compendium also includes an updated version of a group additivity method for evaluating total phase change entropies which together with the fusion temperature can be useful in estimating total phase change enthalpies. Other uses include application in identifying potential substances that either form liquid or plastic crystals or exhibit additional phase changes such as undetected solid-solid transitions or behave anisotropically in the liquid state.

  19. Ionic liquid-based dispersive liquid-liquid microextraction with back-extraction coupled with capillary electrophoresis to determine phenolic compounds.

    PubMed

    Zhou, Caihong; Tong, Shanshan; Chang, Yunxia; Jia, Qiong; Zhou, Weihong

    2012-04-01

    Ionic liquid (IL) based dispersive liquid-liquid microextraction (DLLME) with back-extraction coupled with capillary electrophoresis ultraviolet detection was developed to determine four phenolic compounds (bisphenol-A, β-naphthol, α-naphthol, 2, 4-dichlorophenol) in aqueous cosmetics. The developed method was used to preconcentrate and clean up the four phenolic compounds including two steps. The analytes were transferred into room temperature ionic liquid (1-octyl-3-methylimidazolium hexafluorophosphate, [C(8) MIM][PF(6) ]) rich-phase in the first step. In the second step, the analytes were back-extracted into the alkaline aqueous phase. The effects of extraction parameters, such as type and volume of extraction solvent, type and volume of disperser, extraction and centrifugal time, sample pH, salt addition, and concentration and volume of NaOH in back-extraction were investigated. Under the optimal experimental conditions, the preconcentration factors were 60.1 for bisphenol-A, 52.7 for β-naphthol, 49.2 for α-naphthol, and 18.0 for 2, 4-dichlorophenol. The limits of detection for bisphenol-A, β-naphthol, α-naphthol and 2, 4-dichlorophenol were 5, 5, 8, and 100 ng mL(-1), respectively. Four kinds of aqueous cosmetics including toner, soften lotion, make-up remover, and perfume were analyzed and yielded recoveries ranging from 81.6% to 119.4%. The main advantages of the proposed method are quick, easy, cheap, and effective.

  20. Determination of volatile compounds in cider apple juices using a covalently bonded ionic liquid coating as the stationary phase in gas chromatography.

    PubMed

    Pello-Palma, Jairo; González-Álvarez, Jaime; Gutiérrez-Álvarez, María Dolores; Dapena de la Fuente, Enrique; Mangas-Alonso, Juan José; Méndez-Sánchez, Daniel; Gotor-Fernández, Vicente; Arias-Abrodo, Pilar

    2017-04-01

    A chromatographic method for the separation of volatile compounds in Asturian cider apple juices has been developed. For this separation purpose, a monocationic imidazolium-based ionic liquid bearing a reactive terminal iodine atom was synthesized by a quaternization-anion exchange chemical sequence. Next, the gas chromatography (GC) stationary phase was prepared by covalently linking the imidazolium monolith to the reactive silanol groups of the inner capillary wall at 70 °C. This coated GC column exhibited good thermal stability (290 °C), as well as good efficiency (2000 plates/m) in the separation of volatile compounds from Asturian apple cider juices, and was characterized using the Abraham solvation parameter model. The intra-day and inter-day precision of the chromatographic method was evaluated, obtaining relative standard deviations from 3.7 to 12.9% and from 7.4 to 18.0%, respectively. Furthermore, recoveries from 82.5 to 122% were achieved. Graphical Abstract Covalent bonding of an ionic liquid to inner column wall led to a great improvement of the separation efficiencies of stationary phases in gas chromatography.

  1. An equation to calculate internuclear distances of covalent, ionic and metallic lattices.

    PubMed

    Lang, Peter F; Smith, Barry C

    2015-02-07

    This paper briefly describes the many different sets of ionic and covalent radii available. A simple model of ionic and covalent bonding is proposed and an equation to calculate internuclear distances of covalent, ionic and metallic lattices is described. Derivation of covalent radii and the use of a proposed model of metallic structure and bonding to derive ionic radii are discussed. A brief summary of the development of the simple equation for calculating internuclear distances of ionic compounds is provided. Values of internuclear distances calculated from the derived radii are compared to observed values and give good agreement, showing strong evidence that ionic and covalent radii are not additive and electronegativity influences bonding and internuclear distances. Ionic radii derived from the proposed model are applied to calculate lattice energies which agree well with literature values/values calculated by the Born Haber cycle. Work functions of transition metals are shown to be simple inverse functions of the derived radii. Internuclear distances of inter-metallic compounds are calculated and compared with observed values to show good agreement. This work shows that the proposed model of metallic structure complements the band theory and expressions introduced in this work can be used to predict ionic and covalent bond lengths (in different environments) that have not yet been determined as well as being a method for resolving bond type.

  2. Detecting ethanol and acetaldehyde by simple and ultrasensitive fluorimetric methods in compound foods.

    PubMed

    Zachut, M; Shapiro, F; Silanikove, N

    2016-06-15

    There is a need for simple, accurate, and rapid analysis of ethanol (Eth) and acetaldehyde (AA) in a wide variety of beverages and foods. A novel enzymatic assay coupled to formation of fluorescent chromophore is presented. Eth detection was further improved by adding semicarbazide to the reaction mixture, which interacts with AA and prevents its inhibitory effect on Eth oxidation. The limits of detection of Eth (0.5 mg/L) and AA (0.9 mg/L) are comparable with the performance of modern gas chromatography techniques. The repeatability of Eth and AA detection in various foods (9% on average) was lower than that with commercial kits (23%). The high sensitivity of the developed method enables detection of AA in common foods [e.g., bio-yogurt (12.2 mg/L), and the existence of endogenous Eth (1.8 mg/L) and AA (2.0 mg/L) in bacteria-free non-fermented bovine milk], which could not measured so far by enzymatic methods.

  3. Comparison of physicochemical and gas chromatographic polarity measures for simple organic compounds.

    PubMed

    Héberger, Károly; Zenkevich, Igor G

    2010-04-23

    The comparison of different polarity measures (parameters, descriptors, variables, scales, etc.) indicates that evaluation of interrelations between these measures is important for better understanding and interpretation of chemical and/or analytical data, especially for chromatographic separation. The best linear correlation between gas chromatographic and non-chromatographic polarity descriptors is revealed for the first time: this pair of variables is the difference of gas chromatographic retention indices on standard polar and non-polar phases as well as the difference between non-dimensional indices of boiling points (known in chromatography since mid-1980s as dispersion indices) and indices of molar refractions. The correlation helps chromatographers to find preferable chemical variables (features) to understand better the separation phenomena and to find better correlations in QSRR models. Principal component analysis (PCA) of ten frequently applied polarity measures shows their similarity and, at the same time, it shows the absence of anomalies within the set of simple organic molecules. A novel ranking method for ten polarity parameters points out that the two most informative polarity measures are (i) the non-dimensional index for boiling point and (ii) the difference in chromatographic retention indices on standard polar and non-polar stationary phases. On the other hand, the hydrophobicity parameter, log P, sometimes considered as polarity parameter in HPLC seems to be the worst one in description of "polarity" in gas chromatography. Surprisingly, such polarity measures like dipole moment and permittivity used often in organic chemistry does not provide the best correlation with gas chromatographic polarity measures.

  4. Eco-friendly ionic liquid based ultrasonic assisted selective extraction coupled with a simple liquid chromatography for the reliable determination of acrylamide in food samples.

    PubMed

    Albishri, Hassan M; El-Hady, Deia Abd

    2014-01-01

    Acrylamide in food has drawn worldwide attention since 2002 due to its neurotoxic and carcinogenic effects. These influences brought out the dual polar and non-polar characters of acrylamide as they enabled it to dissolve in aqueous blood medium or penetrate the non-polar plasma membrane. In the current work, a simple HPLC/UV system was used to reveal that the penetration of acrylamide in non-polar phase was stronger than its dissolution in polar phase. The presence of phosphate salts in the polar phase reduced the acrylamide interaction with the non-polar phase. Furthermore, an eco-friendly and costless coupling of the HPLC/UV with ionic liquid based ultrasonic assisted extraction (ILUAE) was developed to determine the acrylamide content in food samples. ILUAE was proposed for the efficient extraction of acrylamide from bread and potato chips samples. The extracts were obtained by soaking of potato chips and bread samples in 1.5 mol L(-1) 1-butyl-3-methylimmidazolium bromide (BMIMBr) for 30.0 and 60.0 min, respectively and subsequent chromatographic separation within 12.0 min using Luna C18 column and 100% water mobile phase with 0.5 mL min(-1) under 25 °C column temperature at 250 nm. The extraction and analysis of acrylamide could be achieved within 2h. The mean extraction efficiency of acrylamide showed adequate repeatability with relative standard deviation (RSD) of 4.5%. The limit of detection and limit of quantitation were 25.0 and 80.0 ng mL(-1), respectively. The accuracy of the proposed method was tested by recovery in seven food samples giving values ranged between 90.6% and 109.8%. Therefore, the methodology was successfully validated by official guidelines, indicating its reliability to be applied to analysis of real samples, proven to be useful for its intended purpose. Moreover, it served as a simple, eco-friendly and costless alternative method over hitherto reported ones.

  5. Combination of ionic self-assembly and hydrogen bonding as a tool for the synthesis of liquid-crystalline materials and organogelators from a simple building block.

    PubMed

    Camerel, Franck; Faul, Charl F J

    2003-08-07

    In this communication we report on the facile combination of hydrogen bonding and the ionic self-assembly (ISA) process to produce organized materials and fiber-containing organogel superstructures from functionalised oligoelectrolytic building blocks.

  6. Feasibility of a simple laboratory approach for determining temperature influence on SPMD–air partition coefficients of selected compounds

    USGS Publications Warehouse

    Cicenaite, Aurelija; Huckins, James N.; Alvarez, David A.; Cranor, Walter L.; Gale, Robert W.; Kauneliene, Violeta; Bergqvist, Per-Anders

    2007-01-01

    Semipermeable membrane devices (SPMDs) are a widely used passive sampling methodology for both waterborne and airborne hydrophobic organic contaminants. The exchange kinetics and partition coefficients of an analyte in a SPMD are mediated by its physicochemical properties and certain environmental conditions. Controlled laboratory experiments are used for determining the SPMD–air (Ksa's) partition coefficients and the exchange kinetics of organic vapors. This study focused on determining a simple approach for measuring equilibrium Ksa's for naphthalene (Naph), o-chlorophenol (o-CPh) and p-dichlorobenzene (p-DCB) over a wide range of temperatures. SPMDs were exposed to test chemical vapors in small, gas-tight chambers at four different temperatures (−16, −4, 22 and 40 °C). The exposure times ranged from 6 h to 28 d depending on test temperature. Ksa's or non-equilibrium concentrations in SPMDs were determined for all compounds, temperatures and exposure periods with the exception of Naph, which could not be quantified in SPMDs until 4 weeks at the −16 °C temperature. To perform this study the assumption of constant and saturated atmospheric concentrations in test chambers was made. It could influence the results, which suggest that flow through experimental system and performance reference compounds should be used for SPMD calibration.

  7. Feasibility of a simple laboratory approach for determining temperature influence on SPMD-air partition coefficients of selected compounds

    USGS Publications Warehouse

    Cicenaite, A.; Huckins, J.N.; Alvarez, D.A.; Cranor, W.L.; Gale, R.W.; Kauneliene, V.; Bergqvist, P.-A.

    2007-01-01

    Semipermeable membrane devices (SPMDs) are a widely used passive sampling methodology for both waterborne and airborne hydrophobic organic contaminants. The exchange kinetics and partition coefficients of an analyte in a SPMD are mediated by its physicochemical properties and certain environmental conditions. Controlled laboratory experiments are used for determining the SPMD-air (Ksa's) partition coefficients and the exchange kinetics of organic vapors. This study focused on determining a simple approach for measuring equilibrium Ksa's for naphthalene (Naph), o-chlorophenol (o-CPh) and p-dichlorobenzene (p-DCB) over a wide range of temperatures. SPMDs were exposed to test chemical vapors in small, gas-tight chambers at four different temperatures (-16, -4, 22 and 40 ??C). The exposure times ranged from 6 h to 28 d depending on test temperature. Ksa's or non-equilibrium concentrations in SPMDs were determined for all compounds, temperatures and exposure periods with the exception of Naph, which could not be quantified in SPMDs until 4 weeks at the -16 ??C temperature. To perform this study the assumption of constant and saturated atmospheric concentrations in test chambers was made. It could influence the results, which suggest that flow through experimental system and performance reference compounds should be used for SPMD calibration. ?? 2006 Elsevier Ltd. All rights reserved.

  8. Nanoporous array anodic titanium-supported co-polymeric ionic liquids as high performance solid-phase microextraction sorbents for hydrogen bonding compounds.

    PubMed

    Jia, Jing; Liang, Xiaojing; Wang, Licheng; Guo, Yong; Liu, Xia; Jiang, Shengxiang

    2013-12-13

    A nanoporous array anodic titanium-supported co-polymeric ionic liquids (NAAT/PILs) solid-phase microextraction (SPME) fiber was prepared in situ on the titanium wire. NAAT was selected as the substrate, in view of its high surface-to-volume ratio, easy preparation, mechanical stability, and rich titanol groups on its surface which can anchor silica coupling agent containing vinyl and then introduce ionic liquid copolymers as sorbents. In this work, 1-vinyl-3-nonanol imidazolium bromide ([C9OHVIm]Br) and 1,4-di(3-vinylimidazolium) butane dibromide ([(VIM)2C4]2[Br]) were synthesized and used as monomer and crosslinker, respectively. Extraction properties of the NAAT/PILs fiber for polar alcohols and volatile fatty acids (VFAs) in aqueous matrix were examined using gaseous sampling-SPME (GS-SPME) and headspace SPME (HS-SPME) mode, respectively. Combining the superior properties of NAAT substrate and the strong hydrogen bond interaction of PILs to polar compounds, the NAAT/PILs SPME fiber showed much higher adsorption affinity to aliphatic alcohols than bare NAAT and pure PILs fibers. The detection limits (LOD) of established GS-SPME-GC-FID method are in the range of 0.35-17.30ngL(-1) with a linear range from 0.01 to 500ngmL(-1). Also, it showed high extraction performance toward volatile fatty acids (VFAs) compounds from aqueous matrix. Under the optimized SPME conditions, wide linear ranges were obtained with correlation coefficients (R(2)) greater than 0.99 and limits of detection were in the range of 0.85-8.74ngL(-1). Moreover, real-world samples were analyzed and good results were obtained.

  9. Modeling of ionic liquids

    NASA Astrophysics Data System (ADS)

    Tatlipinar, Hasan

    2017-02-01

    Ionic liquids are very important entry to industry and technology. Because of their unique properties they may classified as a new class of materials. IL usually classified as a high temperature ionic liquids (HTIL) and room temperature ionic liquids (RTIL). HTIL are molten salts. There are many research studies on molten salts such as recycling, new energy sources, rare elements mining. RTIL recently become very important in daily life industry because of their "green chemistry" properties. As a simple view ionic liquids consist of one positively charged and one negatively charged components. Because of their Coulombic or dispersive interactions the local structure of ionic liquids emerges. In this presentation the local structural properties of the HTIL are discussed via correlation functions and integral equation theories. RTIL are much more difficult to do modeling, but still general consideration for the modeling of the HTIL is valid also for the RTIL.

  10. Identifying Students' Misconceptions in Writing Balanced Equations for Dissolving Ionic Compounds in Water and Using Multiple-Choice Questions at the Symbolic and Particulate Levels to Confront These Misconceptions

    ERIC Educational Resources Information Center

    Naah, Basil M.

    2012-01-01

    Students who harbor misconceptions often find chemistry difficult to understand. To improve teaching about the dissolving process, first semester introductory chemistry students were asked to complete a free-response questionnaire on writing balanced equations for dissolving ionic compounds in water. To corroborate errors and misconceptions…

  11. Electric field-assisted solid phase extraction and cleanup of ionic compounds in complex food matrices: Fluoroquinolones in eggs.

    PubMed

    Ribeiro, Cyntia Cabral; Orlando, Ricardo Mathias; Rohwedder, Jarbas José Rodrigues; Reyes, Felix Guillermo Reyes; Rath, Susanne

    2016-05-15

    The use of electric fields as additional driving forces in sample preparation techniques is an innovative approach that is environmentally friendly, straightforward, and able to overcome several limitations of conventional sample preparation procedures. In this work, the advantages of electric field-assisted solid phase extraction (E-SPE) using syringe-type cartridges were demonstrated for the extraction of four fluoroquinolones (FQs) in their anionic forms. The FQs were extracted from eggs and subsequently determined by UHPLC-MS/MS. The use of electric fields during the washing and final elution steps resulted in a significant improvement of the extraction efficiencies for almost all FQs when compared to conventional SPE. Intra- and inter-day assays showed coefficients of variation below 10%. The better cleanup also resulted in the appearance of less precipitated matter in the final eluate, as well as reduced matrix effects. The results showed that the electrophoretic forces derived from electric fields are a promising way of significantly increasing the extraction efficiency of ionic analytes, while minimizing matrix effects associated with complex samples.

  12. A simple method to optimize the HSCCC two-phase solvent system by predicting the partition coefficient for target compound.

    PubMed

    Han, Quan-Bin; Wong, Lina; Yang, Nian-Yun; Song, Jing-Zheng; Qiao, Chun-Feng; Yiu, Hillary; Ito, Yoichiro; Xu, Hong-Xi

    2008-04-01

    A simple method was developed to optimize the solvent ratio of the two-phase solvent system used in the high-speed counter-current chromatography (HSCCC) separation. Some mathematic equations, such as the exponential and the power equations, were established to describe the relationship between the solvent ratio and the partition coefficient. Using this new method, the two-phase solvent system was easily optimized to obtain a proper partition coefficient for the CCC separation of the target compound. Furthermore, this method was satisfactorily applied in determining the two-phase solvent system for the HSCCC preparation of pseudolaric acid B from the Chinese herb Pseudolarix kaempferi Gordon (Pinaceae). The two-phase solvent system of n-hexane/EtOAc/MeOH/H(2)O (5:5:5:5 by volume) was used with a good partition coefficient K = 1.08. As a result, 232.05 mg of pseudolaric acid B was yielded from 0.5 g of the crude extract with a purity of 97.26% by HPLC analysis.

  13. A simple and predictive phenotypic High Content Imaging assay for Plasmodium falciparum mature gametocytes to identify malaria transmission blocking compounds

    PubMed Central

    Lucantoni, Leonardo; Silvestrini, Francesco; Signore, Michele; Siciliano, Giulia; Eldering, Maarten; Dechering, Koen J.; Avery, Vicky M.; Alano, Pietro

    2015-01-01

    Plasmodium falciparum gametocytes, specifically the mature stages, are the only malaria parasite stage in humans transmissible to the mosquito vector. Anti-malarial drugs capable of killing these forms are considered essential for the eradication of malaria and tools allowing the screening of large compound libraries with high predictive power are needed to identify new candidates. As gametocytes are not a replicative stage it is difficult to apply the same drug screening methods used for asexual stages. Here we propose an assay, based on high content imaging, combining “classic” gametocyte viability readout based on gametocyte counts with a functional viability readout, based on gametocyte activation and the discrimination of the typical gamete spherical morphology. This simple and rapid assay has been miniaturized to a 384-well format using acridine orange staining of wild type P. falciparum 3D7A sexual forms, and was validated by screening reference antimalarial drugs and the MMV Malaria Box. The assay demonstrated excellent robustness and ability to identify quality hits with high likelihood of confirmation of transmission reducing activity in subsequent mosquito membrane feeding assays. PMID:26553647

  14. Cathodic Deposition of Components in BiSbTe Ternary Compounds as Thermoelectric Films Using Choline-Chloride-Based Ionic Liquids

    NASA Astrophysics Data System (ADS)

    Golgovici, Florentina; Cojocaru, Anca; Nedelcu, Marin; Visan, Teodor

    2010-09-01

    This paper reports electrodeposition of BiTe, SbTe, and BiSbTe films using ionic liquids based on choline chloride (ChCl) and malonic acid mixtures (1:1 moles) at 80°C to 85°C. The electrolyte contained bismuth and/or antinomy species and tellurium species with 1.5 mM to 50 mM concentrations; Pt sheet, Pt mesh, and Pt wire were used for working, auxiliary, and quasireference electrodes, respectively. Cyclic voltammograms revealed the beginning and cathodic peak of pure Te deposition; at more negative potentials simultaneous codeposition of binary or ternary compounds as limiting currents or a series of peaks were observed. Correspondingly, two or three dissolution (stripping) anodic peaks were observed. Nyquist and Bode impedance spectra show differences in Pt behavior due to its polarization at various cathodic potentials. Equivalent-circuit components providing the best fit to the data were calculated. Deposition of BiSbTe films on copper plates was also performed by electrolysis at controlled potentials or current pulses. Some measurements of Seebeck coefficients of the obtained films were carried out.

  15. Graphene oxide reinforced polymeric ionic liquid monolith solid-phase microextraction sorbent for high-performance liquid chromatography analysis of phenolic compounds in aqueous environmental samples.

    PubMed

    Sun, Min; Bu, Yanan; Feng, Juanjuan; Luo, Chuannan

    2016-01-01

    A graphene oxide reinforced polymeric ionic liquids monolith was obtained by copolymerization of graphene oxide doped 1-(3-aminopropyl)-3-(4-vinylbenzyl)imidazolium 4-styrenesulfonate monomer and 1,6-di-(3-vinylimidazolium) hexane bihexafluorophosphate cross-linking agent. Coupled to high-performance liquid chromatography, the monolith was used as a solid-phase microextraction sorbent to analyze several phenolic compounds in aqueous samples. Under the optimized extraction and desorption conditions, linear ranges were 5-400 μg/L for 3-nitrophenol, 2-nitrophenol, and 2,5-dichlorophenol and 2-400 μg/L for 4-chlorophenol, 2-methylphenol, and 2,4,6-trichlorophenol (R(2) = 0.9973-0.9988). The limits of detection were 0.5 μg/L for 3-nitrophenol and 2-nitrophenol and 0.2 μg/L for the rest of the analytes. The proposed method was used to determine target analytes in groundwater from an industrial park and river water. None of the analytes was detected. Relative recoveries were in the range of 75.5-113%.

  16. Application of ionic liquid-based dispersive liquid phase microextraction for highly sensitive simultaneous determination of three endocrine disrupting compounds in food packaging.

    PubMed

    Wang, Lingling; Zhang, Danfeng; Xu, Xu; Zhang, Lei

    2016-04-15

    Ionic liquid (IL) dispersive liquid-liquid microextraction (DLLME) method was successfully developed for extracting three endocrine disrupting compounds (EDCs) (bisphenol A, bisphenol AF and bisphenol AP) from the food packaging. 1-Octyl-3-methylimidazoliumhexafluorophosphate ([C8MIM][PF6]) was selected as extraction solution. The extraction procedure did not require a dispersive solvent. Three EDCs extraction kinetics were found to be very fast and the equilibrium was attained within 3.0 min following the pseudo-first-order model. The H-bonding and hydrophobic interactions play an important role in the partitioning of EDCs into IL from aqueous solution. The recovered IL could be reused for three runs without significant loss of extraction efficiencies. The spiked recoveries of three targets in food packaging were in the range of 97.8-103.1%. The limits of detection ranged from 0.50 to 1.50 ng mL(-1) (S/N=3). As a result, this method has been successfully applied for the sensitive detection of three EDCs in real samples.

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

    SciTech Connect

    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.

  18. Pyrolysis of simple coal model compounds containing aromatic carboxylic acids: Does decarboxylation lead to cross-linking?

    SciTech Connect

    Eskay, T.P.; Britt, P.F.; Buchanan, A.C. III

    1996-02-01

    The thermolysis of two aromatic carboxylic acids 1,2-(3,3`-dicarboxyphenyl)ethane (2) have been investigated at 400{degree} C as models of carboxylic acids in low rank coals. The major decomposition pathway observed is decarboxylation, which mainly occurs by an ionic pathway. This decarboxylation route does not lead to any significant amount of coupling or high molecular weight products that would be indicative of cross-linking products in coal. The pyrolysis of 1 and 2 will be investigated under a variety of conditions that better mimic the enviromment found in coal to further delineate the role that decarboxylation plays in coal cross-linking chemistry.

  19. The role of ionic sizes in inducing the cubic to tetragonal distortion in AV2O4 and ACr2O4 (A = Zn, Mg and Cd) compounds

    NASA Astrophysics Data System (ADS)

    Lal, Sohan; Pandey, Sudhir K.

    2016-11-01

    Cubic to tetragonal distortion in AV2O4 and ACr2O4 (A = Zn, Mg and Cd) compounds have been a contentious issue for last two decades. Different groups have proposed different mechanisms to understand such a distortion in these spinels, which are: (i) spin lattice coupling mechanism known as the spin driven Jahn-Teller (JT) effect, (ii) the strong relativistic spin-orbit coupling, a moderate JT distortion and weak V-V interactions and (iii) the JT effect. Now, in order to know the possible cause for such a distortion, we have avoided these complexities (various interactions among spin, electronic, orbital and lattice degrees of freedom) by carrying out spin unpolarized calculations. The calculated values of bulk moduli for ZnV2O4 (ZnCr2O4), MgV2O4 (MgCr2O4) and CdV2O4 (CdCr2O4) are found to be ˜289 (˜254), ˜244 (˜243) and ˜230 (˜233) GPa, respectively which suggest that CdV2O4 (among vanadates) and CdCr2O4 (among chromates) are more compressible. For vanadates and chromates, the order of calculated values of lattice parameter a are found to CdV2O4 > MgV2O4 > ZnV2O4 and CdCr2O4 > MgCr2O4 > ZnCr2O4, respectively and are consistent with the experimental results. The calculated values of cubic to tetragonal distortion (c/a), with c/a < 1 for ZnV2O4 (ZnCr2O4), MgV2O4 (MgCr2O4) and CdV2O4 (CdCr2O4) are ˜0.996 (˜0.997), ˜0.995 (˜0.994) and ˜0.997 (˜0.998), respectively. These values are in good agreement with the experimental data for ZnV2O4, MgV2O4, ZnCr2O4 and MgCr2O4 compounds. The present study clearly shows the role of ionic sizes in inducing the cubic to tetragonal distortion in these spinels. However, the discrepancies between the calculated and experimental data for CdV2O4 and CdCr2O4 are expected to improve by considering the above mentioned mechanisms. These mechanisms also appear to be responsible for deciding the other physical properties of these compounds.

  20. Synthesis of ionic liquids

    DOEpatents

    Dai, Sheng; Luo, Huimin

    2011-11-01

    Ionic compounds which are liquids at room temperature are formed by the method of mixing a neutral organic ligand with the salt of a metal cation and its conjugate anion. The liquids are hydrophobic, conductive and stable and have uses as solvents and in electrochemical devices.

  1. Synthesis of ionic liquids

    DOEpatents

    Dai, Sheng [Knoxville, TN; Luo, Huimin [Knoxville, TN

    2008-09-09

    Ionic compounds which are liquids at room temperature are formed by the method of mixing a neutral organic liqand with the salt of a metal cation and its conjugate anion. The liquids are hydrophobic, conductive and stable and have uses as solvents and in electrochemical devices.

  2. Molecular solutes in ionic liquids: a structural perspective.

    PubMed

    Pádua, Agílio A H; Costa Gomes, Margarida F; Canongia Lopes, José N A

    2007-11-01

    Understanding physicochemical properties of ionic liquids is important for their rational use in extractions, reactions, and other applications. Ionic liquids are not simple fluids: their ions are generally asymetric, flexible, with delocalized electrostatic charges, and available in a wide variety. It is difficult to capture their subtle properties with models that are too simplistic. Molecular simulation using atomistic force fields, which describe structures and interactions in detail, is an excellent tool to gain insights into their liquid-state organization, how they solvate different compounds, and what molecular factors determine their properties. The identification of certain ionic liquids as self-organized phases, with aggregated nonpolar and charged domains, provides a new way to interpret the solvation and structure of their mixtures. Many advances are the result of a successful interplay between experiment and modeling, possible in this field where none of the two methodologies had a previous advance.

  3. Nonaqueous Electrolyte Systems Ionic Transport in Nonaqueous Media.

    DTIC Science & Technology

    ALUMINATES, *IONIC CURRENT), (*ELECTROLYTES, ALUMINA), (*SULFITES, ELECTROLYTES), SODIUM COMPOUNDS, ELECTRICAL CONDUCTIVITY, TRANSPORT PROPERTIES, SOLUTIONS(MIXTURES), PERCHLORATES, FLUOBORATES , LITHIUM COMPOUNDS, VISCOSITY

  4. SIMPOL.1: a simple group contribution method for predicting vapor pressures and enthalpies of vaporization of multifunctional organic compounds

    NASA Astrophysics Data System (ADS)

    Pankow, J. F.; Asher, W. E.

    2008-05-01

    The SIMPOL.1 group contribution method is developed for predicting the liquid vapor pressure poL (atm) and enthalpy of vaporization Δ Hvap (kJ mol-1) of organic compounds as functions of temperature (T). For each compound i, the method assumes log10poL,i (T)=∑kνk,ibk(T) where νk,i is the number of groups of type k, and bk (T) is the contribution to log10poL,i (T) by each group of type k. A zeroeth group is included that uses b0 (T) with ν0,i=1 for all i. A total of 30 structural groups are considered: molecular carbon, alkyl hydroxyl, aromatic hydroxyl, alkyl ether, alkyl ring ether, aromatic ether, aldehyde, ketone, carboxylic acid, ester, nitrate, nitro, alkyl amine (primary, secondary, and tertiary), aromatic amine, amide (primary, secondary, and tertiary), peroxide, hydroperoxide, peroxy acid, C=C, carbonylperoxynitrate, nitro-phenol, nitro-ester, aromatic rings, non-aromatic rings, C=C-C=O in a non-aromatic ring, and carbon on the acid-side of an amide. The T dependence in each of the bk (T) is assumed to follow b(T)=B1/T+B2+B3T+B4ln T. Values of the B coefficients are fit using an initial basis set of 272 compounds for which experimentally based functions po L,i=fi (T) are available. The range of vapor pressure considered spans fourteen orders of magnitude. The ability of the initially fitted B coefficients to predict poL values is examined using a test set of 184 compounds and a T range that is as wide as 273.15 to 393.15 K for some compounds. σFIT is defined as the average over all points of the absolute value of the difference between experimental and predicted values of log10poL,i (T). After consideration of σFIT for the test set, the initial basis set and test set compounds are combined, and the B coefficients re-optimized. For all compounds and temperatures, σFIT=0.34: on average, poL,i (T) values are predicted to within a factor of 2. Because d(log10 poL,i (T))d(1/T) is related to the enthalpy of vaporization ΔHvap,i, the fitted B provide

  5. SIMPOL.1: A simple group contribution method for predicting vapor pressures and enthalpies of vaporization of multifunctional organic compounds

    NASA Astrophysics Data System (ADS)

    Pankow, J. F.; Asher, W. E.

    2007-08-01

    The SIMPOL.1 group contribution method is developed for predicting the liquid vapor pressure pLo (atm) and enthalpy of vaporization ΔHvap (kJ mol-1) of organic compounds as functions of temperature (T). For each compound i, the method assumes log10pL,io(T)=Σkνk,ibk(T) where νk,i is the number of groups of type k, and bk(T) is the contribution to log10 pL,io(T) by each group of type k. A zeroeth group is included that uses b0(T) with ν0,i=1 for all i. A total of 30 structural groups are considered: molecular carbon, alkyl hydroxyl, aromatic hydroxyl, alkyl ether, alkyl ring ether, aromatic ether, aldehyde, ketone, carboxylic acid, ester, nitrate, nitro, alkyl amine (primary, secondary, and tertiary), aromatic amine, amide (primary, secondary, and tertiary), peroxide, hydroperoxide, peroxy acid, C=C, carbonylperoxynitrate, nitro-phenol, nitro-ester, aromatic rings, non-aromatic rings, C=C-C=O in a non-aromatic ring, and carbon on the acid-side of an amide. The T dependence in each of the bk(T) is assumed to follow b(T)=B1/T+B2+B3T+B4lnT. Values of the B coefficients are fit using an initial basis set of 272 compounds for which experimentally based functions pL,io=fi(T) are available. The range of vapor pressure considered spans fourteen orders of magnitude. The ability of the initially fitted B coefficients to predict pLo values is examined using a test set of 161 compounds and a T range that is as wide as 273.15 to 393.15 K for some compounds. σFIT is defined as the average over all points of the absolute value of the difference between experimental and predicted values of log10pL,io(T). After consideration of σFIT for the test set, the initial basis set and test set compounds are combined, and the B coefficients re-optimized. For all compounds and temperatures, σFIT=0.34: on average, pL,io(T) values are predicted to within a factor of 2. Because d(log10pL,io(T))/d(1/T) is related to the enthalpy of vaporization ΔHvap,i, the fitted B provide predictions of

  6. Compound

    NASA Astrophysics Data System (ADS)

    Suzumura, Akitoshi; Watanabe, Masaki; Nagasako, Naoyuki; Asahi, Ryoji

    2014-06-01

    Recently, Cu-based chalcogenides such as Cu3SbSe4, Cu2Se, and Cu2SnSe3 have attracted much attention because of their high thermoelectric performance and their common feature of very low thermal conductivity. However, for practical use, materials without toxic elements such as selenium are preferable. In this paper, we report Se-free Cu3SbS4 thermoelectric material and improvement of its figure of merit ( ZT) by chemical substitutions. Substitutions of 3 at.% Ag for Cu and 2 at.% Ge for Sb lead to significant reductions in the thermal conductivity by 37% and 22%, respectively. These substitutions do not sacrifice the power factor, thus resulting in enhancement of the ZT value. The sensitivity of the thermal conductivity to chemical substitutions in these compounds is discussed in terms of the calculated phonon dispersion and previously proposed models for Cu-based chalcogenides. To improve the power factor, we optimize the hole carrier concentration by substitution of Ge for Sb, achieving a power factor of 16 μW/cm K2 at 573 K, which is better than the best reported for Se-based Cu3SbSe4 compounds.

  7. Chemical reaction networks as a model to describe UVC- and radiolytically-induced reactions of simple compounds.

    PubMed

    Dondi, Daniele; Merli, Daniele; Albini, Angelo; Zeffiro, Alberto; Serpone, Nick

    2012-05-01

    When a chemical system is submitted to high energy sources (UV, ionizing radiation, plasma sparks, etc.), as is expected to be the case of prebiotic chemistry studies, a plethora of reactive intermediates could form. If oxygen is present in excess, carbon dioxide and water are the major products. More interesting is the case of reducing conditions where synthetic pathways are also possible. This article examines the theoretical modeling of such systems with random-generated chemical networks. Four types of random-generated chemical networks were considered that originated from a combination of two connection topologies (viz., Poisson and scale-free) with reversible and irreversible chemical reactions. The results were analyzed taking into account the number of the most abundant products required for reaching 50% of the total number of moles of compounds at equilibrium, as this may be related to an actual problem of complex mixture analysis. The model accounts for multi-component reaction systems with no a priori knowledge of reacting species and the intermediates involved if system components are sufficiently interconnected. The approach taken is relevant to an earlier study on reactions that may have occurred in prebiotic systems where only a few compounds were detected. A validation of the model was attained on the basis of results of UVC and radiolytic reactions of prebiotic mixtures of low molecular weight compounds likely present on the primeval Earth.

  8. Predictive modeling studies for the ecotoxicity of ionic liquids towards the green algae Scenedesmus vacuolatus.

    PubMed

    Das, Rudra Narayan; Roy, Kunal

    2014-06-01

    Hazardous potential of ionic liquids is becoming an issue of high concern with increasing application of these compounds in various industrial processes. Predictive toxicological modeling on ionic liquids provides a rational assessment strategy and aids in developing suitable guidance for designing novel analogues. The present study attempts to explore the chemical features of ionic liquids responsible for their ecotoxicity towards the green algae Scenedesmus vacuolatus by developing mathematical models using extended topochemical atom (ETA) indices along with other categories of chemical descriptors. The entire study has been conducted with reference to the OECD guidelines for QSAR model development using predictive classification and regression modeling strategies. The best models from both the analyses showed that ecotoxicity of ionic liquids can be decreased by reducing chain length of cationic substituents and increasing hydrogen bond donor feature in cations, and replacing bulky unsaturated anions with simple saturated moiety having less lipophilic heteroatoms.

  9. Simple model designed to generate new crystal structures derived from a mother phase; application to molecular compounds.

    PubMed

    Gervais, Claire; Coquerel, Gérard

    2002-08-01

    The basic principles of a model predicting new lattices from a known crystal structure are described. The first of the two-step procedure consists of extracting one- or two-dimensional periodic fragments (PF) from the mother structure. In the second step, symmetry operators are added to the PFs in order to generate one or several new three-dimensional lattices consistent with the 230 space groups. Most of the examples are related to polymorphism, but relationships between racemic compounds and enantiomers, twinning and lamellar epitaxy phenomena are also exemplified.

  10. F+ and F⁻ affinities of simple N(x)F(y) and O(x)F(y) compounds.

    PubMed

    Grant, Daniel J; Wang, Tsang-Hsiu; Vasiliu, Monica; Dixon, David A; Christe, Karl O

    2011-03-07

    Atomization energies at 0 K and heats of formation at 0 and 298 K are predicted for the neutral and ionic N(x)F(y) and O(x)F(y) systems using coupled cluster theory with single and double excitations and including a perturbative triples correction (CCSD(T)) method with correlation consistent basis sets extrapolated to the complete basis set (CBS) limit. To achieve near chemical accuracy (±1 kcal/mol), three corrections to the electronic energy were added to the frozen core CCSD(T)/CBS binding energies: corrections for core-valence, scalar relativistic, and first order atomic spin-orbit effects. Vibrational zero point energies were computed at the CCSD(T) level of theory where possible. The calculated heats of formation are in good agreement with the available experimental values, except for FOOF because of the neglect of higher order correlation corrections. The F(+) affinity in the N(x)F(y) series increases from N(2) to N(2)F(4) by 63 kcal/mol, while that in the O(2)F(y) series decreases by 18 kcal/mol from O(2) to O(2)F(2). Neither N(2) nor N(2)F(4) is predicted to bind F(-), and N(2)F(2) is a very weak Lewis acid with an F(-) affinity of about 10 kcal/mol for either the cis or trans isomer. The low F(-) affinities of the nitrogen fluorides explain why, in spite of the fact that many stable nitrogen fluoride cations are known, no nitrogen fluoride anions have been isolated so far. For example, the F(-) affinity of NF is predicted to be only 12.5 kcal/mol which explains the numerous experimental failures to prepare NF(2)(-) salts from the well-known strong acid HNF(2). The F(-) affinity of O(2) is predicted to have a small positive value and increases for O(2)F(2) by 23 kcal/mol, indicating that the O(2)F(3)(-) anion might be marginally stable at subambient temperatures. The calculated adiabatic ionization potentials and electron affinities are in good agreement with experiment considering that many of the experimental values are for vertical processes.

  11. A simple QSPR model for the prediction of the adsorbability of organic compounds onto activated carbon cloth.

    PubMed

    Xu, J; Zhu, L; Fang, D; Liu, L; Bai, Z; Wang, L; Xu, W

    2013-01-01

    A quantitative structure-property relationship (QSPR) model was proposed between the molecular descriptors representing the molecular structure and the Freundlich adsorbability parameter (K) for a set of 55 organic compounds onto activated carbon cloth. The best linear model was composed of three descriptors, which were selected by stepwise multiple linear regression (MLR) analysis. The statistical parameters provided by the linear model were r² = 0.7744, r²(adj) = 0.7551, s = 0.169 for the training set; and r² = 0.6725, r²(adj) = 0.6316, s = 0.196 for the external test set, respectively. The stability and predictive power of the proposed model were further verified using Y-randomization tests, five-fold cross-validation and leave-many-out cross-validation. The model may give some insight into the main structural features that affect the adsorption of the investigated compounds onto activated carbon cloth.

  12. Overloaded elution band profiles of ionizable compounds in reversed-phase liquid chromatography: Influence of the competition between the neutral and the ionic species

    SciTech Connect

    Gritti, Fabrice; Guiochon, Georges A

    2008-01-01

    The parameters that affect the shape of the band profiles of acido-basic compounds under moderately overloaded conditions (sample size less than 500 nmol for a conventional column) in RPLC are discussed. Only analytes that have a single pK{sub a} are considered. In the buffer mobile phase used for their elution, their dissociation may, under certain conditions, cause a significant pH perturbation during the passage of the band. Two consecutive injections (3.3 and 10 {micro}L) of each one of three sample solutions (0.5, 5, and 50 mM) of ten compounds were injected on five C{sub 18}-bonded packing materials, including the 5 {micro}m Xterra-C{sub 18} (121 {angstrom}), 5 {micro}m Gemini-C{sub 18} (110 {angstrom}), 5 {micro}m Luna-C{sub 18}(2) (93 {angstrom}), 3.5 {micro}m Extend-C{sub 18} (80 {angstrom}), and 2.7 {micro}m Halo-C{sub 18} (90 {angstrom}). The mobile phase was an aqueous solution of methanol buffered at a constant {sub W}{sup W}pH of 6, with a phosphate buffer. The total concentration of the phosphate groups was constant at 50 mM. The methanol concentration was adjusted to keep all the retention factors between 1 and 10. The compounds injected were phenol, caffeine, 3-phenyl 1-propanol, 2-phenyl butyric acid, amphetamine, aniline, benzylamine, p-toluidine, procainamidium chloride, and propranololium chloride. Depending on the relative values of the analyte pK{sub a} and the buffer solution pH, these analytes elute as the neutral, the cationic, or the anionic species. The influence of structural parameters such as the charge, the size, and the hydrophobicity of the analytes on the shape of its overloaded band profile is discussed. Simple but general rules predict these shapes. An original adsorption model is proposed that accounts for the unusual peak shapes observed when the analyte is partially dissociated in the buffer solution during its elution.

  13. Characterization of sulfur and nitrogen compounds in Brazilian petroleum derivatives using ionic liquid capillary columns in comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometric detection.

    PubMed

    Cappelli Fontanive, Fernando; Souza-Silva, Érica Aparecida; Macedo da Silva, Juliana; Bastos Caramão, Elina; Alcaraz Zini, Claudia

    2016-08-26

    Diesel and naphtha samples were analyzed using ionic liquid (IL) columns to evaluate the best column set for the investigation of organic sulfur compounds (OSC) and nitrogen(N)-containing compounds analyses with comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry detector (GC×GC/TOFMS). Employing a series of stationary phase sets, namely DB-5MS/DB-17, DB-17/DB-5MS, DB-5MS/IL-59, and IL-59/DB-5MS, the following parameters were systematically evaluated: number of tentatively identified OSC, 2D chromatographic space occupation, number of polyaromatic hydrocarbons (PAH) and OSC co-elutions, and percentage of asymmetric peaks. DB-5MS/IL-59 was chosen for OSC analysis, while IL59/DB-5MS was chosen for nitrogen compounds, as each stationary phase set provided the best chromatographic efficiency for these two classes of compounds, respectively. Most compounds were tentatively identified by Lee and Van den Dool and Kratz retention indexes, and spectra-matching to library. Whenever available, compounds were also positively identified via injection of authentic standards.

  14. A novel lattice energy calculation technique for simple inorganic crystals

    NASA Astrophysics Data System (ADS)

    Kaya, Cemal; Kaya, Savaş; Banerjee, Priyabrata

    2017-01-01

    In this pure theoretical study, a hitherto unexplored equation based on Shannon radii of the ions forming that crystal and chemical hardness of any crystal to calculate the lattice energies of simple inorganic ionic crystals has been presented. To prove the credibility of this equation, the results of the equation have been compared with experimental outcome obtained from Born-Fajans-Haber- cycle which is fundamentally enthalpy-based thermochemical cycle and prevalent theoretical approaches proposed for the calculation of lattice energies of ionic compounds. The results obtained and the comparisons made have demonstrated that the new equation is more useful compared to other theoretical approaches and allows to exceptionally accurate calculation of lattice energies of inorganic ionic crystals without doing any complex calculations.

  15. Importance of cross-correlated relaxation in the spectra of simple organofluorine compounds: Spectral complexity of A3B3X spin systems compared to ABX spin systems

    NASA Astrophysics Data System (ADS)

    Alemany, Lawrence B.; Malloy, Thomas B.; Nunes, Megan M.; Zaibaq, Nicholas G.

    2012-09-01

    In a continuation of our initial investigation of the complex 13C and 19F spectra exhibited by two simple organofluorine compounds, additional organofluorine compounds expected to exhibit a wide range of spectral complexity were studied. Spectral simulations are critical for analyzing the more complex spin systems, in particular, A3B3X and A6B3X. Cross-correlated relaxation is commonly observed; examples of 13Csbnd 19F cross-correlated relaxation are shown with the signals for each nucleus exhibiting unequal relaxation rates. Higher order effects are particularly noticeable in the spectra of perfluoro-t-butyl alcohol because of a large 4JFF value in the (13CF3)(12CF3)212COH isotopomer. The many additional transitions in an A3B3X spin system compared to an ABX spin system result in much more complex 19F (A3 and B3) and 13C (X) spectra, even though only three types of nuclei are involved in each spin system. The corresponding protio compounds typically constitute a much simpler A3M3X spin system because the long-range nJHH coupling (n ⩾ 4) is much smaller than the corresponding long-range nJFF coupling. Spectra previously published for ethane-1-13C (A3B3X) and hexafluoroethane-1-13C (A3M3X) are notable exceptions and are discussed.

  16. Influence of activated carbon porosity and surface oxygen functionalities' presence on adsorption of acetonitrile as a simple polar volatile organic compound.

    PubMed

    Furmaniak, Sylwester

    2015-01-01

    Based on series of porous carbon models, systematic Monte Carlo studies on the adsorption of acetonitrile (as a simple representative of polar volatile organic compounds) were performed. The influence of porosity and chemical composition of the carbon surface on CH3CN adsorption was studied and it was shown that both the factors influenced the adsorption mechanism. A decrease in the pore size and the introduction of oxygen surface groups led to a rise in adsorption energy and to an increase in the filling of accessible volume in the low-pressure part of the isotherm. However, from a practical point of view, it is easier to increase the adsorption by introducing polar groups on the carbon surface than by modifying the porosity.

  17. Simultaneous estimation of glass-water distribution and PDMS-water partition coefficients of hydrophobic organic compounds using simple batch method.

    PubMed

    Hsieh, Min-Kai; Fu, Chung-Te; Wu, Shian-chee

    2011-09-15

    A simple batch method by use of refilling and nonrefilling experimental procedures and headspace solid phase microextraction was applied to simultaneously obtain the glass-water distribution coefficients (K(GW)) and polydimethylsiloxane(PDMS)-water partition coefficients (K(PW)) of hydrophobic organic compounds (HOCs). The simple batch method takes into consideration the glass-surface bound HOCs and the corresponding equilibrium distribution of HOCs among the glass, water, headspace, and polydimethylsiloxane (PDMS). The K(PW) and K(GW) values of 53 PCB congeners were determined. The glass-bound fraction predominated over other fractions for highly chlorinated PCBs. Ignoring glass adsorption and assuming a complete mass balance could thus substantially underestimate the K(PW) for HOCs in traditional work. Good linear correlations of logα (the overall mass transfer rate constant) vs logK(PW), logK(PW) vs logK(OW), and logK(GW) vs logK(OW) were observed, with logα = -0.91 logK(PW) + 1.13, R(2) = 0.93; logK(PW) = 1.032 logK(OW) - 0.493, R(2) = 0.947; and logK(GW) = 0.93 logK(OW) - 2.30, R(2) = 0.90. The K(PW) values from this study were compared with those in the literature. With an account of the glass adsorption, the accuracy of the K(PW) determination and the estimation of the dissolved concentration in water for highly hydrophobic compounds can be significantly improved.

  18. Pyrrolidinium ionic liquid crystals.

    PubMed

    Goossens, Karel; Lava, Kathleen; Nockemann, Peter; Van Hecke, Kristof; Van Meervelt, Luc; Driesen, Kris; Görller-Walrand, Christiane; Binnemans, Koen; Cardinaels, Thomas

    2009-01-01

    N-alkyl-N-methylpyrrolidinium cations have been used for the design of ionic liquid crystals, including a new type of uranium-containing metallomesogen. Pyrrolidinium salts with bromide, bis(trifluoromethylsulfonyl)imide, tetrafluoroborate, hexafluorophosphate, thiocyanate, tetrakis(2- thenoyltrifluoroacetonato)europate(III) and tetrabromouranyl counteranions were prepared. For the bromide salts and tetrabromouranyl compounds, the chain length of the alkyl group C(n)H(2n+1) was varied from eight to twenty carbon atoms (n = 8, 10-20). The compounds show rich mesomorphic behaviour: highly ordered smectic phases (the crystal smectic E phase and the uncommon crystal smectic T phase), smectic A phases, and hexagonal columnar phases were observed, depending on chain length and anion. This work gives better insight into the nature and formation of the crystal smectic T phase, and the molecular requirements for the appearance of this highly ordered phase. This uncommon tetragonal mesophase is thoroughly discussed on the basis of detailed powder X-ray diffraction experiments and in relation to the existing literature. Structural models are proposed for self-assembly of the molecules within the smectic layers. In addition, the photophysical properties of the compounds containing a metal complex anion were investigated. For the uranium-containing mesogens, luminescence can be induced by dissolving them in an ionic liquid matrix. The europium-containing compound shows intense red photoluminescence with high colour purity.

  19. Structures and heats of formation of simple alkali metal compounds: hydrides, chlorides, fluorides, hydroxides, and oxides for Li, Na, and K.

    PubMed

    Vasiliu, Monica; Li, Shenggang; Peterson, Kirk A; Feller, David; Gole, James L; Dixon, David A

    2010-04-01

    Geometry parameters, frequencies, heats of formation, and bond dissociation energies are predicted for simple alkali metal compounds (hydrides, chlorides, fluorides, hydroxides and oxides) of Li, Na, and K from coupled cluster theory [CCSD(T)] calculations including core-valence correlation with the aug-cc-pwCVnZ basis set (n = D, T, Q, and 5). To accurately calculate the heats of formation, the following additional correction were included: scalar relativistic effects, atomic spin-orbit effects, and vibrational zero-point energies. For calibration purposes, the properties of some of the lithium compounds were predicted with iterative triple and quadruple excitations via CCSDT and CCSDTQ. The calculated geometry parameters, frequencies, heats of formation, and bond dissociation energies were compared with all available experimental measurements and are in excellent agreement with high-quality experimental data. High-level calculations are required to correctly predict that K(2)O is linear and that the ground state of KO is (2)Sigma(+), not (2)Pi, as in LiO and NaO. This reliable and consistent set of calculated thermodynamic data is appropriate for use in combustion and atmospheric simulations.

  20. Ionic Liquid Crystals: Versatile Materials.

    PubMed

    Goossens, Karel; Lava, Kathleen; Bielawski, Christopher W; Binnemans, Koen

    2016-04-27

    This Review covers the recent developments (2005-2015) in the design, synthesis, characterization, and application of thermotropic ionic liquid crystals. It was designed to give a comprehensive overview of the "state-of-the-art" in the field. The discussion is focused on low molar mass and dendrimeric thermotropic ionic mesogens, as well as selected metal-containing compounds (metallomesogens), but some references to polymeric and/or lyotropic ionic liquid crystals and particularly to ionic liquids will also be provided. Although zwitterionic and mesoionic mesogens are also treated to some extent, emphasis will be directed toward liquid-crystalline materials consisting of organic cations and organic/inorganic anions that are not covalently bound but interact via electrostatic and other noncovalent interactions.

  1. Betaine and Carnitine Derivatives as Herbicidal Ionic Liquids.

    PubMed

    Pernak, Juliusz; Niemczak, Michał; Chrzanowski, Łukasz; Ławniczak, Łukasz; Fochtman, Przemysław; Marcinkowska, Katarzyna; Praczyk, Tadeusz

    2016-08-16

    This study focused on the synthesis and subsequent characterization of herbicidal ionic liquids based on betaine and carnitine, two derivatives of amino acids, which were used as cations. Four commonly used herbicides (2,4-D, MCPA, MCPP and Dicamba) were used as anions in simple (single anion) and oligomeric (two anions) salts. The obtained salts were subjected to analyzes regarding physicochemical properties (density, viscosity, refractive index, thermal decomposition profiles and solubility) as well as evaluation of their herbicidal activity under greenhouse and field conditions, toxicity towards rats and biodegradability. The obtained results suggest that the synthesized herbicidal ionic liquids displayed low toxicity (classified as category 4 compounds) and showed similar or improved efficacy against weed compared to reference herbicides. The highest increase was observed during field trials for salts containing 2,4-D as the anion, which also exhibited the highest biodegradability (>75 %).

  2. An Alternative to the Ionic Model

    ERIC Educational Resources Information Center

    Sanderson, R. T.

    1975-01-01

    Describes the "coordinated polymeric model," which yields more accurate energy calculations than the "ionic model" for compounds which exhibit considerable covalency. The dichotomy between ionic and covalent bonding is thus largely broken down for solids which are nonmolecular in the crystalline state. (MLH)

  3. Thermodynamic estimation: Ionic materials

    SciTech Connect

    Glasser, Leslie

    2013-10-15

    Thermodynamics establishes equilibrium relations among thermodynamic parameters (“properties”) and delineates the effects of variation of the thermodynamic functions (typically temperature and pressure) on those parameters. However, classical thermodynamics does not provide values for the necessary thermodynamic properties, which must be established by extra-thermodynamic means such as experiment, theoretical calculation, or empirical estimation. While many values may be found in the numerous collected tables in the literature, these are necessarily incomplete because either the experimental measurements have not been made or the materials may be hypothetical. The current paper presents a number of simple and relible estimation methods for thermodynamic properties, principally for ionic materials. The results may also be used as a check for obvious errors in published values. The estimation methods described are typically based on addition of properties of individual ions, or sums of properties of neutral ion groups (such as “double” salts, in the Simple Salt Approximation), or based upon correlations such as with formula unit volumes (Volume-Based Thermodynamics). - Graphical abstract: Thermodynamic properties of ionic materials may be readily estimated by summation of the properties of individual ions, by summation of the properties of ‘double salts’, and by correlation with formula volume. Such estimates may fill gaps in the literature, and may also be used as checks of published values. This simplicity arises from exploitation of the fact that repulsive energy terms are of short range and very similar across materials, while coulombic interactions provide a very large component of the attractive energy in ionic systems. Display Omitted - Highlights: • Estimation methods for thermodynamic properties of ionic materials are introduced. • Methods are based on summation of single ions, multiple salts, and correlations. • Heat capacity, entropy

  4. Nanoparticles in ionic liquids: interactions and organization.

    PubMed

    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.

  5. Membrane separation of ionic liquid solutions

    DOEpatents

    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.

  6. First principles approach to ionicity of fragments

    NASA Astrophysics Data System (ADS)

    Pilania, Ghanshyam; Liu, Xiang-Yang; Valone, Steven M.

    2015-02-01

    We develop a first principles approach towards the ionicity of fragments. In contrast to the bond ionicity, the fragment ionicity refers to an electronic property of the constituents of a larger system, which may vary from a single atom to a functional group or a unit cell to a crystal. The fragment ionicity is quantitatively defined in terms of the coefficients of contributing charge states in a superposition of valence configurations of the system. Utilizing the constrained density functional theory-based computations, a practical method to compute the fragment ionicity from valence electron charge densities, suitably decomposed according to the Fragment Hamiltonian (FH) model prescription for those electron densities, is presented for the first time. The adopted approach is illustrated using BeO, MgO and CaO diatomic molecules as simple examples. The results are compared and discussed with respect to the bond ionicity scales of Phillips and Pauling.

  7. Comparative in vitro study of cholinium-based ionic liquids and deep eutectic solvents toward fish cell line.

    PubMed

    Radošević, Kristina; Železnjak, Jelena; Cvjetko Bubalo, Marina; Radojčić Redovniković, Ivana; Slivac, Igor; Gaurina Srček, Višnja

    2016-09-01

    With the advent of ionic liquids, much was expected concerning their applicability as an alternative to organic solvents in the chemical technology and biotechnology fields. However, the most studied and commonly used ionic liquids based on imidazolium and pyridinium were found not to be as environmentally friendly as it was first expected. Therefore, a new generation of alternative solvents named natural ionic liquids and deep eutectic solvents, composed of natural and/or renewable compounds, have come into focus in recent years. Since the number of newly synthesized chemicals increases yearly, simple and reliable methods for their ecotoxicological assessment are necessary. Permanent fish cell lines can serve as a test system for the evaluation of a chemical's cytotoxicity. This paper presents research results on the cytotoxic effects on Channel Catfish Ovary (CCO) cell line induced by fifteen cholinium-based ionic liquids and deep eutectic solvents. Based on the decrease in cell viability, the most obvious toxic effect on CCO cells was caused by ionic liquid choline oxalate, while other solvents tested exhibited low cytotoxicity. Therefore, we can conclude that cholinium-based ionic liquids and deep eutectic solvents are comparatively less toxic to CCO cells than conventional ionic liquids.

  8. Simple Machines Made Simple.

    ERIC Educational Resources Information Center

    St. Andre, Ralph E.

    Simple machines have become a lost point of study in elementary schools as teachers continue to have more material to cover. This manual provides hands-on, cooperative learning activities for grades three through eight concerning the six simple machines: wheel and axle, inclined plane, screw, pulley, wedge, and lever. Most activities can be…

  9. Structural phase transitions of ionic layered PbFX (X = Cl{sup −}or Br{sup –}) compounds under high pressure

    SciTech Connect

    Sorb, Y.A. Sornadurai, D.

    2015-05-15

    The PbFX (X = Cl{sup –}or Br{sup –}) compounds crystallize in tetragonal structure with space group P4/nmm. High pressure X-ray diffraction studies carried out on PbFCl compound reveals that it undergoes pressure induced structural transitions at ∼18 GPa and ∼38 GPa to orthorhombic and monoclinic (P2{sub 1}/m) phases respectively. Like PbFCl, a similar phase transition from tetragonal to orthorhombic phase is observed in PbFBr at intermediate pressure. These phase transitions seem to be similar to the transitions involving other matlockite structure compounds such as BaFX (X = Cl{sup –}, Br{sup –}or I{sup –}). PbFCl has a larger structural stability range compared to BaFCl and is attributed to the large anisotropic coordination of the Pb{sup 2+} and Cl{sup –}ions.

  10. NMR Diffusion Measurements as a Simple Method to Examine Solvent-Solvent and Solvent-Solute Interactions in Mixtures of the Ionic Liquid [Bmim][N(SO2 CF3 )2 ] and Acetonitrile.

    PubMed

    Keaveney, Sinead T; Schaffarczyk McHale, Karin S; Stranger, James W; Ganbold, Batchimeg; Price, William S; Harper, Jason B

    2016-12-05

    The self-diffusion coefficients of each component in mixtures of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([Bmim][N(SO2 CF3 )2 ]) and acetonitrile were determined. The results suggest that the hydrodynamic boundary conditions change from "stick" to "slip" as the solvent composition transitions from "ionic liquid dissolved in acetonitrile" (χIL <0.4) to "acetonitrile dissolved in ionic liquid" (χIL >0.4). At higher χIL , the acetonitrile species are affected by "cage" and "jump" events, as the acetonitrile molecules reside nearer to the charged centre on the ions than in the "non-polar" regions. The self-diffusion coefficients of hexan-1-amine, dipropylamine, 1-hexanol and dipropylether in mixtures of [Bmim][N(SO2 CF3 )2 ] and acetonitrile were determined. In general, the nitrogen-containing solutes were found to diffuse slower than the oxygen-containing solutes; this indicates that there are greater ionic liquid-N interactions than ionic liquid-O interactions. This work demonstrates that the self-diffusion coefficients of species can provide valuable information about solvent-solvent and solvent-solute interactions in mixtures containing an ionic liquid.

  11. Robust surface nano-architecture by alkali-carboxylate ionic bonding.

    PubMed

    Skomski, Daniel; Abb, Sabine; Tait, Steven L

    2012-08-29

    Ionic bonding in supramolecular surface networks is a promising strategy to self-assemble nanostructures from organic building blocks with atomic precision. However, sufficient thermal stability of such systems has not been achieved at metal surfaces, likely due to partial screening of the ionic interactions. We demonstrate excellent stability of a self-assembled ionic network on a metal surface at elevated temperatures. The structure is characterized directly by atomic resolution scanning tunneling microscopy (STM) experiments conducted at 165 °C showing intact domains. This robust nanometer-scale structure is achieved by the on-surface reaction of a simple and inexpensive compound, sodium chloride, with a model system for carboxylate interactions, terephthalic acid (TPA). Rather than distinct layers of TPA and NaCl, angle resolved X-ray photoelectron spectroscopy experiments indicate a replacement reaction on the Cu(100) surface to form Na-carboxylate ionic bonds. Chemical shifts in core level electron states confirm a direct interaction and a +1 charge state of the Na. High-temperature STM imaging shows virtually no fluctuation of Na-TPA island boundaries, revealing a level of thermal stability that has not been previously achieved in noncovalent organic-based nanostructures at surfaces. Comparable strength of intermolecular ionic bonds and intramolecular covalent bonds has been achieved in this surface system. The formation of these highly ordered structures and their excellent thermal stability is dependent on the interplay of adsorbate-substrate and ionic interactions and opens new possibilities for ionic self-assemblies at surfaces with specific chemical function. Robust ionic surface structures have potential uses in technologies requiring high thermal stability and precise ordering through self-assembly.

  12. Monitoring and evaluating the quality consistency of Compound Bismuth Aluminate tablets by a simple quantified ratio fingerprint method combined with simultaneous determination of five compounds and correlated with antioxidant activities.

    PubMed

    Liu, Yingchun; Liu, Zhongbo; Sun, Guoxiang; Wang, Yan; Ling, Junhong; Gao, Jiayue; Huang, Jiahao

    2015-01-01

    A combination method of multi-wavelength fingerprinting and multi-component quantification by high performance liquid chromatography (HPLC) coupled with diode array detector (DAD) was developed and validated to monitor and evaluate the quality consistency of herbal medicines (HM) in the classical preparation Compound Bismuth Aluminate tablets (CBAT). The validation results demonstrated that our method met the requirements of fingerprint analysis and quantification analysis with suitable linearity, precision, accuracy, limits of detection (LOD) and limits of quantification (LOQ). In the fingerprint assessments, rather than using conventional qualitative "Similarity" as a criterion, the simple quantified ratio fingerprint method (SQRFM) was recommended, which has an important quantified fingerprint advantage over the "Similarity" approach. SQRFM qualitatively and quantitatively offers the scientific criteria for traditional Chinese medicines (TCM)/HM quality pyramid and warning gate in terms of three parameters. In order to combine the comprehensive characterization of multi-wavelength fingerprints, an integrated fingerprint assessment strategy based on information entropy was set up involving a super-information characteristic digitized parameter of fingerprints, which reveals the total entropy value and absolute information amount about the fingerprints and, thus, offers an excellent method for fingerprint integration. The correlation results between quantified fingerprints and quantitative determination of 5 marker compounds, including glycyrrhizic acid (GLY), liquiritin (LQ), isoliquiritigenin (ILG), isoliquiritin (ILQ) and isoliquiritin apioside (ILA), indicated that multi-component quantification could be replaced by quantified fingerprints. The Fenton reaction was employed to determine the antioxidant activities of CBAT samples in vitro, and they were correlated with HPLC fingerprint components using the partial least squares regression (PLSR) method. In

  13. Monitoring and Evaluating the Quality Consistency of Compound Bismuth Aluminate Tablets by a Simple Quantified Ratio Fingerprint Method Combined with Simultaneous Determination of Five Compounds and Correlated with Antioxidant Activities

    PubMed Central

    Liu, Yingchun; Liu, Zhongbo; Sun, Guoxiang; Wang, Yan; Ling, Junhong; Gao, Jiayue; Huang, Jiahao

    2015-01-01

    A combination method of multi-wavelength fingerprinting and multi-component quantification by high performance liquid chromatography (HPLC) coupled with diode array detector (DAD) was developed and validated to monitor and evaluate the quality consistency of herbal medicines (HM) in the classical preparation Compound Bismuth Aluminate tablets (CBAT). The validation results demonstrated that our method met the requirements of fingerprint analysis and quantification analysis with suitable linearity, precision, accuracy, limits of detection (LOD) and limits of quantification (LOQ). In the fingerprint assessments, rather than using conventional qualitative “Similarity” as a criterion, the simple quantified ratio fingerprint method (SQRFM) was recommended, which has an important quantified fingerprint advantage over the “Similarity” approach. SQRFM qualitatively and quantitatively offers the scientific criteria for traditional Chinese medicines (TCM)/HM quality pyramid and warning gate in terms of three parameters. In order to combine the comprehensive characterization of multi-wavelength fingerprints, an integrated fingerprint assessment strategy based on information entropy was set up involving a super-information characteristic digitized parameter of fingerprints, which reveals the total entropy value and absolute information amount about the fingerprints and, thus, offers an excellent method for fingerprint integration. The correlation results between quantified fingerprints and quantitative determination of 5 marker compounds, including glycyrrhizic acid (GLY), liquiritin (LQ), isoliquiritigenin (ILG), isoliquiritin (ILQ) and isoliquiritin apioside (ILA), indicated that multi-component quantification could be replaced by quantified fingerprints. The Fenton reaction was employed to determine the antioxidant activities of CBAT samples in vitro, and they were correlated with HPLC fingerprint components using the partial least squares regression (PLSR) method

  14. Use of ionic liquids as coordination ligands for organometallic catalysts

    DOEpatents

    Li, Zaiwei; Tang, Yongchun; Cheng; Jihong

    2009-11-10

    Aspects of the present invention relate to compositions and methods for the use of ionic liquids with dissolved metal compounds as catalysts for a variety of chemical reactions. Ionic liquids are salts that generally are liquids at room temperature, and are capable of dissolving a many types of compounds that are relatively insoluble in aqueous or organic solvent systems. Specifically, ionic liquids may dissolve metal compounds to produce homogeneous and heterogeneous organometallic catalysts. One industrially-important chemical reaction that may be catalyzed by metal-containing ionic liquid catalysts is the conversion of methane to methanol.

  15. Preparation of a novel ionic hybrid stationary phase by non-covalent functionalization of single-walled carbon nanotubes with amino-derivatized silica gel for fast HPLC separation of aromatic compounds.

    PubMed

    Aral, Hayriye; Çelik, K Serdar; Aral, Tarık; Topal, Giray

    2016-03-01

    Single-walled carbon nanotubes (SWCNTs) were immobilized on spherical silica gel with a 4-μm average particle size and a 60-Å average pore size. The amino-derivatized silica gel was non-covalently coated with carboxylated SWCNTs to preserve the structure of the nanotubes and their physico-chemical properties. The novel ionic hybrid stationary phase was characterized by scanning electron microscopy (SEM), infra-red (IR) spectroscopy and elemental analysis, and then, it was used to fill an empty 150×4.6mm(2) high-performance liquid chromatography (HPLC) column. Chromatographic parameters, such as the theoretical plate number, retention factor and peak asymmetry factor, and analytical parameters, such as the limit of detection (LOD), limit of quantification (LOQ), linear range, calibration equation, and R(2) value, and quantitative analysis parameters were calculated for all of the analytes. Using different mobile phases, five different classes of aromatic hydrocarbons were separated in a very short analysis time of 4-8min. Furthermore, a high theoretical plate number (up to 25000) and an excellent peak asymmetry factor (1.0) were obtained. The results showed that the surface of the SWNTs had very strong interactions with aromatic groups, therefore providing high selectivity for the separation of different classes of aromatic compounds. This study indicates that SWCNTs enable the extension of the application range of the newly prepared stationary phases for the fast separation of aromatic compounds by HPLC.

  16. Ionic liquids intercalated in montmorillonite as the sorptive phase for the extraction of low-polarity organic compounds from water by rotating-disk sorptive extraction.

    PubMed

    Fiscal-Ladino, Jhon A; Obando-Ceballos, Mónica; Rosero-Moreano, Milton; Montaño, Diego F; Cardona, Wilson; Giraldo, Luis F; Richter, Pablo

    2017-02-08

    Montmorillonite (MMT) clays were modified by the intercalation into their galleries of ionic liquids (IL) based on imidazolium quaternary ammonium salts. This new eco-materials exhibited good features for use as a sorptive phase in the extraction of low-polarity analytes from aqueous samples. Spectroscopic analyses of the modified clays were conducted and revealed an increase in the basal spacing and a shifting of the reflection plane towards lower values as a consequence of the effective intercalation of organic cations into the MMT structure. The novel sorbent developed herein was assayed as the sorptive phase in rotating-disk sorptive extraction (RDSE), using polychlorinated biphenyls (PCBs), representative of low-polarity pollutants, as model analytes. The final determination was made by gas chromatography with electron capture detection. Among the synthetized sorptive phases, the selected system for analytical purposes consisted of MMT modified with the 1-hexadecyl-3-methylimidazolium bromide (HDMIM-Br) IL. Satisfactory analytical features were achieved using a sample volume of 5 mL: the relative recoveries from a wastewater sample were higher than 80%, the detection limits were between 3 ng L(-1) and 43 ng L(-1), the precision (within-run precision) expressed as the relative standard deviation ranged from 2% to 24%, and the enrichment factors ranged between 18 and 28. Using RDSE, the extraction efficiency achieved for the selected MMT-HDMIM-Br phase was compared with other commercial solid phases/supports, such as polypropylene, polypropylene with 1-octanol (as a supported liquid membrane), octadecyl (C18) and octyl (C8), and showed the highest response for all the studied analytes. Under the optimized extraction conditions, this new device was applied in the analysis of the influent of a wastewater treatment plant in Santiago (Chile), demonstrating its applicability through the good recoveries and precision achieved with real samples.

  17. Diphenyl diselenide, a simple organoselenium compound, decreases methylmercury-induced cerebral, hepatic and renal oxidative stress and mercury deposition in adult mice.

    PubMed

    de Freitas, Andressa Sausen; Funck, Vinícius Rafael; Rotta, Mariana dos Santos; Bohrer, Denise; Mörschbächer, Vanessa; Puntel, Robson Luís; Nogueira, Cristina Wayne; Farina, Marcelo; Aschner, Michael; Rocha, João Batista Teixeira

    2009-04-06

    Oxidative stress has been pointed out as an important molecular mechanism in methylmercury (MeHg) intoxication. At low doses, diphenyl diselenide ((PhSe)2), a structurally simple organoselenium compound, has been shown to possess antioxidant and neuroprotective properties. Here we have examined the possible in vivo protective effect of diphenyl diselenide against the potential pro-oxidative effects of MeHg in mouse liver, kidney, cerebrum and cerebellum. The effects of MeHg exposure (2 mg/(kg day) of methylmercury chloride 10 ml/kg, p.o.), as well as the possible antagonist effect of diphenyl diselenide (1 and 0.4 mg/(kg day); s.c.) on body weight gain and on hepatic, cerebellar, cerebral and renal levels of thiobarbituric acid reactive substances (TBARS), non-protein thiols (NPSH), ascorbic acid content, mercury concentrations and activities of antioxidant enzymes (glutathione peroxidase (GPx), catalase (CAT) and superoxide dismutase (SOD)) were evaluated after 35 days of treatment. MeHg caused an increase in TBARS and decreased NPSH levels in all tissues. MeHg also induced a decrease in hepatic ascorbic acid content and in renal GPx and CAT activities. Diphenyl diselenide (1 mg/kg) conferred protection against MeHg-induced hepatic and renal lipid peroxidation and at both doses prevented the reduction in hepatic NPSH levels. Diphenyl diselenide also conferred a partial protection against MeHg-induced oxidative stress (TBARS and NPSH) in liver and cerebellum. Of particular importance, diphenyl diselenide decreased the deposition of Hg in cerebrum, cerebellum, kidney and liver. The present results indicate that diphenyl diselenide can protect against some toxic effects of MeHg in mice. This protection may be related to its antioxidant properties and its ability to reduce Hg body burden. We posit that formation of a selenol intermediate, which possesses high nucleophilicity and high affinity for MeHg, accounts for the ability of diphenyl diselenide to ameliorate Me

  18. On the Ambiphilic Reactivity of Geometrically Constrained Phosphorus(III) and Arsenic(III) Compounds: Insights into Their Interaction with Ionic Substrates

    PubMed Central

    Robinson, Thomas P.; Lo, Siu‐Kwan; De Rosa, Daniel; Aldridge, Simon

    2016-01-01

    Abstract The ambiphilic nature of geometrically constrained Group 15 complexes bearing the N,N‐bis(3,5‐di‐tert‐butyl‐2‐phenolate)amide pincer ligand (ONO3−) is explored. Despite their differing reactivity towards nucleophilic substrates with polarised element–hydrogen bonds (e.g., NH3), both the phosphorus(III), P(ONO) (1 a), and arsenic(III), As(ONO) (1 b), compounds exhibit similar reactivity towards charged nucleophiles and electrophiles. Reactions of 1 a and 1 b with KOtBu or KNPh2 afford anionic complexes in which the nucleophilic anion associates with the pnictogen centre ([(tBuO)Pn(ONO)]− (Pn=P (2 a), As (2 b)) and [(Ph2N)Pn(ONO)]− (Pn=P (3 a), As (3 b)). Compound 2 a can subsequently be reacted with a proton source or benzylbromide to afford the phosphorus(V) compounds (tBuO)HP(ONO) (4 a) and (tBuO)BzP(ONO) (5 a), respectively, whereas analogous arsenic(V) compounds are inaccessible. Electrophilic substrates, such as HOTf and MeOTf, preferentially associate with the nitrogen atom of the ligand backbone of both 1 a and 1 b, giving rise to cationic species that can be rationalised as either ammonium salts or as amine‐stabilised phosphenium or arsenium complexes ([Pn{ON(H)O}]+ (Pn=P (6 a), As (6 b)) and [Pn{ON(Me)O}]+ (Pn=P (7 a), As (7 b)). Reaction of 1 a with an acid bearing a nucleophilic counteranion (such as HCl) gives rise to a phosphorus(V) compound HPCl(ONO) (8 a), whereas the analogous reaction with 1 b results in the addition of HCl across one of the As−O bonds to afford ClAs{(H)ONO} (8 b). Functionalisation at both the pnictogen centre and the ligand backbone is also possible by reaction of 7 a/7 b with KOtBu, which affords the neutral species (tBuO)Pn{ON(Me)O} (Pn=P (9 a), As (9 b)). The ambiphilic reactivity of these geometrically constrained complexes allows some insight into the mechanism of reactivity of 1 a towards small molecules, such as ammonia and water. PMID

  19. Auxin transport inhibitor induced low complexity petiolated leaves and sessile leaf-like stipules and architectures of heritable leaf and stipule mutants in Pisum sativum suggest that its simple lobed stipules and compound leaf represent ancestral forms in angiosperms.

    PubMed

    Kumar, Arvind; Sharma, Vishakha; Khan, Moinuddin; Hindala, Mali Ram; Kumar, Sushil

    2013-04-01

    In angiosperms, leaf and stipule architectures are inherited species-specific traits. Variation in leaf and stipule sizes, and forms result from the interaction between abiotic and biotic stimuli, and gene regulatory network(s) that underlie the leaf and stipule developmental programme(s). Here, correspondence between variation in leaf and stipule architectures described for extant angiosperms and that induced mutationally and by imposition of stress in model angiosperm species, especially in Pisum sativum, was detected. Following inferences were drawn from the observations. (i) Several leaf forms in P. sativum have origin in fusion of stipule and leaf primordia. Perfoliate (and amplexicaul and connate) simple sessile leaves and sessile adnate leaves are the result of such primordial fusions. Reversal of changes in the gene regulatory network responsible for fusion products are thought to restore original stipule and leaf conditions. (ii) Compound leaf formation in several different model plants, is a result of promotion of pathways for such condition by gene regulatory networks directed by KNOx1 and LEAFY transcription factors or intercalation of the gene networks directed by them. (iii) Gene regulatory network for compound leaves in P. sativum when mutated generates highly complex compound leaves on one hand and simple leaves on other hand. These altered conditions are mutationally reversible. (vi) Simple leaves in model plants such as Arabidopsis thaliana despite overexpression of KNOx1 orthologues do not become compound. (v) All forms of leaves, including simple leaf, probably have origins in a gene regulatory network of the kind present in P. sativum.

  20. Alkaline ionic liquids applied in supported ionic liquid catalyst for selective hydrogenation of citral to citronellal

    NASA Astrophysics Data System (ADS)

    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.

  1. Ionic Liquids Database- (ILThermo)

    National Institute of Standards and Technology Data Gateway

    SRD 147 Ionic Liquids Database- (ILThermo) (Web, free access)   IUPAC Ionic Liquids Database, ILThermo, is a free web research tool that allows users worldwide to access an up-to-date data collection from the publications on experimental investigations of thermodynamic, and transport properties of ionic liquids as well as binary and ternary mixtures containing ionic liquids.

  2. A simple screening assay for the most common JK*0 alleles revealed compound heterozygosity in Jk(a-b-) probands from Guam.

    PubMed

    Wester, E S; Gustafsson, J; Snell, B; Spruell, P; Hellberg, A; Olsson, M L; Storry, J R

    2009-01-01

    The Jk(a-b-) phenotype results from alterations in the JK gene and is characterized by absence of the RBC urea transporter in the cell membrane. The frequency of Jk(a-b-) varies among populations,but this phenotype is most commonly found in people of Polynesian and Finnish descent. Although rare, Jk(a-b-) individuals present a clinical challenge because anti-Jk3 is produced readily in response to transfusion and pregnancy, and Jk(a-b-) blood is not routinely available. Identification of Jk(a-b-) patients and donors is most often performed serologically. However, ten JK*0 alleles have been identified, and this information can be used in DNA-based typing. We selected five JK*0 alleles that had been encountered by our reference laboratory in two or more samples from unrelated individuals and designed an allele-specific primer PCR assay for use as an initial screening tool. After in-house validation,we tested genomic DNA from a family: a mother and her two sons referred to us for genetic investigation of their Jk(a-b-)phenotypes. Two different nucleotide substitutions, -1g>a in intron 5 (IVS5) and 956C>T in exon 10, originally associated with Polynesian and Indian/African populations respectively, were identified in the family. The mother and one son were compound heterozygotes, and the second son was homozygous for IVS5-1g>a. We conclude that the effort to design and validate such a screening assay was cost-efficient when compared with DNA sequencing costs. Furthermore, selection of the more common JK*0 mutations was a practical approach that resulted in rapid identification of the genetic bases behind the Jk(a-b-) phenotypes in this unusual family. Although an obvious target for eventual inclusion into high-throughput genotyping platforms for clinical diagnostic services, current systems are very limited. Our approach provides a simple and inexpensive method for the identification of these rare alleles.

  3. A rapid and simple pretreatment method for benzoylurea insecticides in honey samples using in-syringe dispersive liquid-liquid microextraction based on the direct solidification of ionic liquids.

    PubMed

    Wang, Huazi; Hu, Lu; Li, Wanzhen; Lu, Runhua; Zhang, Sanbing; Zhou, Wenfeng; Gao, Haixiang

    2016-11-04

    A pretreatment method using in-syringe dispersive liquid-liquid microextraction based on the direct solidification of ionic liquids before high performance liquid chromatography analysis was developed for the determination of benzoylurea insecticides (BUs) in honey samples. The hydrophobic ionic liquid [N4444][PF6], formed in situ by the hydrophilic ionic liquid [N4444]Cl and the ion exchange reagent KPF6, was used to extract the target analytes. The entire extraction procedure was performed in a syringe. The extractant was solidified at room temperature and collected using a nylon membrane filter. This technique did not require a dispersive solvent, vortex mixer, ultrasound bath, or centrifugation. The parameters affecting the extraction efficiency were investigated through an experimental design. Under the optimal conditions, the limits of detection for the four BUs varied from 0.21 to 0.42μgL(-1) in solution (2.1-4.2μgkg(-1) in honey). Good linearities were obtained in the range of 2-300μgL(-1), with coefficients of determination greater than 0.999. The recoveries of the four BUs ranged from 80.94% to 84.59%. The intra-day (n=3) and inter-day (n=3) relative standard deviations were less than 5.08%. Finally, the proposed method was applied to the determination of BUs in commercial honey samples with satisfactory results.

  4. Antinociception produced by Thalassia testudinum extract BM-21 is mediated by the inhibition of acid sensing ionic channels by the phenolic compound thalassiolin B

    PubMed Central

    2011-01-01

    Background Acid-sensing ion channels (ASICs) have a significant role in the sensation of pain and constitute an important target for the search of new antinociceptive drugs. In this work we studied the antinociceptive properties of the BM-21 extract, obtained from the sea grass Thalassia testudinum, in chemical and thermal models of nociception in mice. The action of the BM-21 extract and the major phenolic component isolated from this extract, a sulphated flavone glycoside named thalassiolin B, was studied in the chemical nociception test and in the ASIC currents of the dorsal root ganglion (DRG) neurons obtained from Wistar rats. Results Behavioral antinociceptive experiments were made on male OF-1 mice. Single oral administration of BM-21 produced a significant inhibition of chemical nociception caused by acetic acid and formalin (specifically during its second phase), and increased the reaction time in the hot plate test. Thalassiolin B reduced the licking behavior during both the phasic and tonic phases in the formalin test. It was also found that BM-21 and thalassiolin B selectively inhibited the fast desensitizing (τ < 400 ms) ASIC currents in DRG neurons obtained from Wistar rats, with a nonsignificant action on ASIC currents with a slow desensitizing time-course. The action of thalassiolin B shows no pH or voltage dependence nor is it modified by steady-state ASIC desensitization or voltage. The high concentration of thalassiolin B in the extract may account for the antinociceptive action of BM-21. Conclusions To our knowledge, this is the first report of an ASIC-current inhibitor derived of a marine-plant extract, and in a phenolic compound. The antinociceptive effects of BM-21 and thalassiolin B may be partially because of this action on the ASICs. That the active components of the extract are able to cross the blood-brain barrier gives them an additional advantage for future uses as tools to study pain mechanisms with a potential therapeutic

  5. Simple and rapid analysis for quantitation of the most important volatile flavor compounds in yogurt by headspace gas chromatography-mass spectrometry.

    PubMed

    Alonso, L; Fraga, M J

    2001-07-01

    The aim of this experiment is to develop a rapid, simplified, direct gas chromatographic (GC) method for the analysis of volatile flavor compounds in yogurt combining a headspace with constant heating temperature and GC with a mass spectrometric detect ion. Repeatability of the method is assessed. The relative standard deviation for individual flavor compounds range from 3.5% for acetaldehyde to 8.4% for acetone, with a total mean value of 52.4 +/- 2.2 mg/kg for all of the studied aroma components. Recovery for individual flavor compounds range from 63.7% for acetone to 82.4% for acetic acid.

  6. Measurement of sub-parts-per-billion levels of carbonyl compounds in marine air by a simple cartridge trapping procedure followed by liquid chromatography

    SciTech Connect

    Xianliang, Zhou; Mopper, K. )

    1990-10-01

    Carbonyl compounds in clean marine air were trapped onto 2,4-dinitrophenylhydrazine- (DNPH-) coated cartridges, and their hydrazone derivatives were separated by HPLC and detected by UV absorbance. More than 20 carbonyl compounds were isolated from marine air with >92% collection efficiency. The technique employs a highly effective reagent purification procedure, which results in much lower blanks compared to previously reported trapping techniques for carbonyl compounds. Blanks were routinely <0.07 ppb for formaldehyde and acetone and <0.02 ppb for the others. Humidity and reactive gases have no detectable effect on collection efficiencies. Carbonyl-DNPH derivatives eluted from the cartridges are stable in acetonitrile for at least 2 weeks, which facilitates field studies. Several previously undetected unknown carbonyl compounds were found in marine air by this technique. Typical results for open ocean and coastal marine air are shown.

  7. Acidic Ionic Liquids.

    PubMed

    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.

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

    PubMed

    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.

  9. Generation of Complex Azabicycles and Carbobicycles from Two Simple Compounds in a Single Operation through a Metal-Free Six-Step Domino Reaction.

    PubMed

    Bock, Christina M; Parameshwarappa, Gangajji; Bönisch, Simon; Neiss, Christian; Bauer, Walter; Hampel, Frank; Görling, Andreas; Tsogoeva, Svetlana B

    2016-04-04

    Aza- and carbobicyclic compounds possess favorable pharmaceutical properties, but they are difficult to access. Herein, we demonstrate an unprecedented organocatalytic two component six-step chemodivergent domino reaction, which provides a straightforward, sustainable and atom economical route to difficult-to-access complex bicyclic architectures: azabicycles and carbobicycles, whose ratios can be controlled by the applied electrophiles and catalysts. Detailed NMR and X-ray studies on the structures and relative stereochemistry of selected compounds are presented. Mechanistic investigations of the chemoselective branching step have been carried out with DFT methods in conjunction with semiempirical van der Waals interactions. This new domino reaction opens up a new vista of generating, in a single operation, new bioactive compounds with strong antiviral properties (EC50 up to 0.071 μM for human cytomegalovirus (HCMV)) outperforming clinically used ganciclovir (EC50 2.6 μM).

  10. Ionic Liquid-Mediated Multi-Walled Carbon Nanotube-Polydimethylsiloxane Fiber for Headspace Solid-Phase Microextraction of Phenolic Compounds in Aqueous Samples by Gas Chromatography Coupled to Flame Ionization Detector.

    PubMed

    Sadri, Minoo; Vatani, Hossein

    2017-02-01

    An ionic liquid-mediated multi-walled carbon nanotube (MWCNT)-polydimethylsiloxane (PDMS) sorbent was developed for headspace solid-phase microextraction (HS-SPME) of phenolic compounds from human urine samples. Sol-gel method was used to prepare this sorbent. For this purpose, MWCNTs were functionalized covalently and were attached chemically to the hydroxyl-terminated PDMS. Prepared fiber showed high thermal stability (over than 320°C) and good lifespan (>210 times). These good performances can be attributed to the performance of carbon nanotubes and sol-gel method. Affecting parameters on the efficiency of HS-SPME were investigated and optimized. Under the optimal conditions, linear dynamic ranges were observed over a range of 0.002-200 ng mL(-1) with limits of detection from 0.0005 to 0.005 ng mL(-1) and limits of quantitation between 0.002 and 0.02 ng mL(-1) The relative standard deviations for one fiber (repeatability) (n = 5) at three different concentrations (0.05, 2 and 100 ng mL(-1)) were obtained from 4.6 up to 6.7% and between fibers or batch to batch (n = 3) (reproducibility) in the range of 5.7-7.8%. Urine samples were used as real samples. All real samples were spiked at 0.5 ng mL(-1) of understudy analytes and the relative recovery percentages obtained from 90.7 to 102.1%.

  11. Bond ionicities in CuBC2 chalcogenides (B=Al, Ga, In; C=S, Se, Te)

    NASA Astrophysics Data System (ADS)

    Merino, J. M.; Díaz, R.; León, M.

    2000-04-01

    The bond ionicities, fi,Cu-C and fi,BC of several CuBC2 (B=Al, Ga, In, and C=S, Se, Te) chalcopyrite compounds are estimated by means of the Phillips-Van Vechten dielectric theory for binary tetrahedral compounds and Levine's extension to multibond crystals in the same way as Neumann [Crystal Res. Technol. 18, 1299 (1983)]. The influence of Cu 3d electrons has been taken into account considering Jaffe-Zunger [Phys. Rev. B 29, 1882 (1984)] band-structure calculations in chalcopyrite compounds, and performing a simple extrapolation for Te compounds. The Cu-C bond susceptibilities have been estimated from the static dielectric constant values obtained by Márquez and Rincón [Phys. Status Solidi B 191, 115 (1995)], and a set of Cu-C bond susceptibilities is proposed. The evaluated fi,Cu-C bond ionicities were found to increase with the atomic fractional coordinate of the C atom, x[anion], indicating that the anion position is a good estimation of the Cu-C bond ionicity.

  12. Short range effective potentials for ionic fluids

    NASA Astrophysics Data System (ADS)

    Clarke, J. H. R.; Smith, W.; Woodcock, L. V.

    1986-02-01

    It is shown that the structure of a simple ionic liquid, potassium chloride, can be reproduced in computer simulations using short range effective pair (SHREP) potentials of a simple form. Aside from the balance between like and unlike particle interactions, the important parameters determining the structure are the depth ɛ and the position r0 of the unlike particle pair energy minimum. The results demonstrate that the long range ordering characteristic of ionic liquids is not a consequence of the long range of Coulomb interactions. It is further shown that first order perturbation theory can be used accurately to calculate the thermodynamic properties of an ionic liquid from a corresponding reference liquid generated using a SHREP potential. These results can be generalized to explain deviations from the Reiss-Mayer-Katz corresponding states law for alkali halides and suggest an alternative scheme, effective depth reduction (EDR), based on values of ɛ for the gas phase ion pairs.

  13. DIRECT FORMATION OF TETRAHYDROPYRANOLS VIA CATALYSIS IN IONIC LIQUID

    EPA Science Inventory

    Utilizing a simple homoallyl alcohol and an aldehyde in the presence of a catalytic amount of cerium triflate, the direct formation of tetrahydropyranol derivatives in ionic liquid is reported.

  14. Methods of producing sulfate salts of cations from heteroatomic compounds and dialkyl sulfates and uses thereof

    DOEpatents

    Friesen, Cody A.; Wolfe, Derek; Johnson, Paul Bryan

    2015-09-29

    Methods of preparing sulfate salts of heteroatomic compounds using dialkyl sulfates as a primary reactant are disclosed. Also disclosed are methods of making ionic liquids from the sulfate salts of the heteroatomic compound, and electrochemical cells comprising the ionic liquids.

  15. Radicals in ionic liquids.

    PubMed

    Strehmel, Veronika

    2012-05-14

    Stable radicals and recombination of photogenerated lophyl radicals are investigated in ionic liquids. The 2,2,6,6-tetramethylpiperidine-1-yloxyl derivatives contain various substituents at the 4-position to the nitroxyl group, including hydrogen-bond-forming or ionic substituents that undergo additional interactions with the individual ions of the ionic liquids. Some of these spin probes contain similar ions to ionic liquids to avoid counter-ion exchange with the ionic liquid. Depending on the ionic liquid anion, the Stokes-Einstein theory or the Spernol-Gierer-Wirtz theory can be applied to describe the temperature dependence of the average rotational correlation time of the spin probe in the ionic liquids. Furthermore, the spin probes give information about the micropolarity of the ionic liquids. In this context the substituent at the 4-position to the nitroxyl group plays a significant role. Covalent bonding of a spin probe to the imidazolium ion results in bulky spin probes that are strongly immobilized in the ionic liquid. Furthermore, lophyl radical recombination in the dark, which is chosen to understand the dynamics of bimolecular reactions in ionic liquids, shows a slow process at longer timescale and a rise time at a shorter timescale. Although various reactions may contribute to the slower process during lophyl radical recombination, it follows a second-order kinetics that does not clearly show solvent viscosity dependence. However, the rise time, which may be attributed to radical pair formation, increases with increasing solvent viscosity.

  16. A simple method for experimental determination of electron temperature and electron density in a nanosecond pulsed longitudinal discharge used for excitation of high-power atomic and ionic metal and metal halide vapour lasers

    NASA Astrophysics Data System (ADS)

    Temelkov, K. A.; Vuchkov, N. K.

    2016-05-01

    A simple method based on the time-resolved measurement of electrical discharge parameters, such as tube voltage and discharge current, is developed and applied for determination of electron temperature and electron density in the discharge period of a nanosecond pulsed longitudinal discharge, exciting high-power DUV Cu+ Ne-CuBr, He-Hg+ and He-Sr+ lasers.

  17. Employing ionic liquids to deposit cellulose on PET fibers.

    PubMed

    Textor, Torsten; Derksen, Leonie; Gutmann, Jochen S

    2016-08-01

    Several ionic liquids are excellent solvents for cellulose. Starting from that finishing of PET fabrics with cellulose dissolved in ionic liquids like 1-ethyl-3-methyl imidazolium acetate, diethylphosphate and chloride, or the chloride of butyl-methyl imidazolium has been investigated. Finishing has been carried out from solutions of different concentrations, using microcrystalline cellulose or cotton and by employing different cross-linkers. Viscosity of solutions has been investigated for different ionic liquids, concentrations, cellulose sources, linkers and temperatures. Since ionic liquids exhibit no vapor pressure, simple pad-dry-cure processes are excluded. Before drying the ionic liquid has to be removed by a rinsing step. Accordingly rinsing with fresh ionic liquid followed by water or the direct rinsing with water have been tested. The amount of cellulose deposited has been investigated by gravimetry, zinc chloride iodine test as well as reactive dyeing. Results concerning wettability, water up-take, surface resistance, wear-resistance or washing stability are presented.

  18. A simple theoretical analysis of the Einstein relation for the DMR (diffusivity-mobility ratio) in Nono compounds on the basis of k.p formalism

    NASA Astrophysics Data System (ADS)

    Singha Roy, Subhamoy

    2011-10-01

    An attempt is made to study the Einstein relation for the diffusivity-mobility ratio (DMR) in nonlinear optical and Optoelectronic compounds on the basis of a newly formulated electron energy spectrum. The results for ternary, III-V and quaternary types of optoelectronic materials form a special case of our generalized investigation. I have also studied the DMR in II-VI, Bi, IV-VI and stressed materials on the basis of various band models as applicable for such focused materials. It has been found taking n-Cd3As2, n-CdGeAs2, n-InAs, n-InSb, n-Hg1-xCdxTe, n-In1-xGaxAsyP1-y lattice matched to InP, CdS, Bi, PbS, PbTe, PbSe and stressed InSb as examples of the aforementioned compounds that the DMR increases with increasing electron concentration in various manners for different band constants of the said materials and the rates of variation are totally band structure dependent. Now the well-known results for non-degenerate wide gap optical and Optoelectronic materials have been obtained as special cases of our generalized theory under definite limiting background.

  19. Supramolecular gelators based on benzenetricarboxamides for ionic liquids.

    PubMed

    Ishioka, Yumi; Minakuchi, Nami; Mizuhata, Minoru; Maruyama, Tatsuo

    2014-02-21

    Supramolecular gelators comprising 1,3,5-benzenetricarboxylic acids and amino acid methyl esters (glycine, L-alanine, L-valine, L-leucine, L-methionine, and L-phenylalanine) for ionic liquids were developed. Ten types of ionic liquids were gelated using the above-mentioned gelators at relatively low concentrations. Field emission-scanning electron microscopy and confocal laser scanning microscopy analyses revealed that these gelators self-assembled into an entangled fibrous structure in ionic liquids, leading to the gelation of the ionic liquids. Comparison studies, involving compounds analogous to the gelators, and Fourier transform infrared spectroscopy measurements suggested that hydrogen bonding played a key role in the self-assembly of the gelator molecules. The ionogels displayed reversible thermal transition characteristics and viscoelastic properties typical of a gel. The gelation of the ionic liquids studied under a wide range of gelator concentrations did not affect the intrinsic conductivity of the ionic liquids.

  20. Hydrophobic ionic liquids

    SciTech Connect

    Koch, V.R.; Nanjundiah, C.; Carlin, R.T.

    1998-10-27

    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 shown in a diagram 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 {minus}} is a non-Lewis acid-containing polyatomic anion having a van der Waals volume exceeding 100 {angstrom}{sup 3}. 4 figs.

  1. Hydrophobic ionic liquids

    DOEpatents

    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.

  2. Development and validation of a simple, sensitive, selective and stability-indicating RP-UPLC method for the quantitative determination of ritonavir and its related compounds.

    PubMed

    Koppala, Srinivasarao; Panigrahi, Bibhuranjan; Raju, S V N; Padmaja Reddy, K; Ranga Reddy, V; Anireddy, Jaya Shree

    2015-01-01

    A simple, sensitive, selective and reproducible stability-indicating ultra-performance liquid chromatographic method was developed for the quantitative determination of degradation products and process-related impurities of Ritonavir in a pharmaceutical dosage form. Chromatographic separation was achieved on a polar embedded Waters Acquity BEH Shield RP18 (100 × 2.1 mm, 1.7 μm) column thermostated at 50°C under gradient elution by using a binary mixture of potassium dihydrogen phosphate (0.01 M, pH 3.5) and acetonitrile at a flow rate of 0.5 mL/min. Chromatogram was monitored at 240 nm using a photodiode array detector. The drug and its related impurities are eluted within 20 min. To prove the stability-indicating power of the method, the drug was subjected to hydrolytic (acid, alkaline and water), oxidative, photolytic and thermal stress conditions. The unknown degradants were identified by the LC-MS-MS method, which revealed protonated molecular ion peaks [M + H](+) at m/z 551.40 for hydrolytic degradants, and m/z 737.60 and m/z 753.40 for photolytic degradants. A plausible mechanism for the formation of degradation and process impurities was proposed. The performance of the method was validated according to the International Conference on Harmonization guidelines.

  3. Clear & Simple

    MedlinePlus

    ... the audience themselves. It is important to get direct audience involvement at some point to test the ... words are defined clearly. Sentences are simple, specific, direct, and written in the active voice. Each idea ...

  4. Ionic liquids as active pharmaceutical ingredients.

    PubMed

    Ferraz, Ricardo; Branco, Luís C; Prudêncio, Cristina; Noronha, João Paulo; Petrovski, Zeljko

    2011-06-06

    Ionic liquids (ILs) are ionic compounds that possess a melting temperature below 100 °C. Their physical and chemical properties are attractive for various applications. Several organic materials that are now classified as ionic liquids were described as far back as the mid-19th century. The search for new and different ILs has led to the progressive development and application of three generations of ILs: 1) The focus of the first generation was mainly on their unique intrinsic physical and chemical properties, such as density, viscosity, conductivity, solubility, and high thermal and chemical stability. 2) The second generation of ILs offered the potential to tune some of these physical and chemical properties, allowing the formation of "task-specific ionic liquids" which can have application as lubricants, energetic materials (in the case of selective separation and extraction processes), and as more environmentally friendly (greener) reaction solvents, among others. 3) The third and most recent generation of ILs involve active pharmaceutical ingredients (API), which are being used to produce ILs with biological activity. Herein we summarize recent developments in the area of third-generation ionic liquids that are being used as APIs, with a particular focus on efforts to overcome current hurdles encountered by APIs. We also offer some innovative solutions in new medical treatment and delivery options.

  5. Recent development of ionic liquid stationary phases for liquid chromatography.

    PubMed

    Shi, Xianzhe; Qiao, Lizhen; Xu, Guowang

    2015-11-13

    Based on their particular physicochemical characteristics, ionic liquids have been widely applied in many fields of analytical chemistry. Many types of ionic liquids were immobilized on a support like silica or monolith as stationary phases for liquid chromatography. Moreover, different approaches were developed to bond covalently ionic liquids onto the supporting materials. The obtained ionic liquid stationary phases show multi-mode mechanism including hydrophobic, hydrophilic, hydrogen bond, anion exchange, π-π, and dipole-dipole interactions. Therefore, they could be used in different chromatographic modes including ion-exchange, RPLC, NPLC and HILIC to separate various classes of compounds. This review mainly summarizes the immobilized patterns and types of ionic liquid stationary phases, their retention mechanisms and applications in the recent five years.

  6. Ionic liquids in tribology.

    PubMed

    Minami, Ichiro

    2009-06-24

    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.

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

    SciTech Connect

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

    1997-01-15

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

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

    PubMed

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

    2011-06-06

    Microemulsions form in mixtures of polar, nonpolar, and amphiphilic molecules. Typical microemulsions employ water as the polar phase. However, microemulsions can form with a polar phase other than water, which hold promise to diversify the range of properties, and hence utility, of microemulsions. Here microemulsions formed by using a room-temperature ionic liquid (RTIL) as the polar phase were created and characterized by using multinuclear NMR spectroscopy. (1)H, (11)B, and (19)F NMR spectroscopy was applied to explore differences between microemulsions formed by using 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF(4)]) as the polar phase with a cationic surfactant, benzylhexadecyldimethylammonium chloride (BHDC), and a nonionic surfactant, Triton X-100 (TX-100). NMR spectroscopy showed distinct differences in the behavior of the RTIL as the charge of the surfactant head group varies in the different microemulsion environments. Minor changes in the chemical shifts were observed for [bmim](+) and [BF(4)](-) in the presence of TX-100 suggesting that the surfactant and the ionic liquid are separated in the microemulsion. The large changes in spectroscopic parameters observed are consistent with microstructure formation with layering of [bmim](+) and [BF(4)](-) and migration of Cl(-) within the BHDC microemulsions. Comparisons with NMR results for related ionic compounds in organic and aqueous environments as well as literature studies assisted the development of a simple organizational model for these microstructures.

  9. Influence of organic solvent on the separation of an ionic liquid from a lignin-ionic liquid mixture.

    PubMed

    Weerachanchai, Piyarat; Lim, Kok Hwa; Lee, Jong-Min

    2014-03-01

    Sixteen solvents added in lignin-ionic liquid mixture provide four types of solubility characteristics. The distinct characteristics can be classified by considering solubility parameters including ET Scale, Kamlet-Taft parameters and solubility parameters. Group 1 solvent shows promising solvents for lignin-ionic liquid separation, contributing full dissolution of ionic liquid with lignin precipitation. Isopropanol, the most potential solvent has solubility properties as following normalized molar electronic transition energies (ET(N))=0.57, hydrogen-bond acidity (α)=0.76 and Hildebrand solubility parameter (δT)=23.58. This study examines potential solvents for ionic recovery, provides simple method of separation and leads to the feasibility of using ionic liquids in industrial applications.

  10. Development of an ionic liquid based dispersive liquid-liquid microextraction method for the analysis of polycyclic aromatic hydrocarbons in water samples.

    PubMed

    Pena, M Teresa; Casais, M Carmen; Mejuto, M Carmen; Cela, Rafael

    2009-09-04

    A simple, rapid and efficient method, ionic liquid based dispersive liquid-liquid microextraction (IL-DLLME), has been developed for the first time for the determination of 18 polycyclic aromatic hydrocarbons (PAHs) in water samples. The chemical affinity between the ionic liquid (1-octyl-3-methylimidazolium hexafluorophosphate) and the analytes permits the extraction of the PAHs from the sample matrix also allowing their preconcentration. Thus, this technique combines extraction and concentration of the analytes into one step and avoids using toxic chlorinated solvents. The factors affecting the extraction efficiency, such as the type and volume of ionic liquid, type and volume of disperser solvent, extraction time, dispersion stage, centrifuging time and ionic strength, were optimised. Analysis of extracts was performed by high performance liquid chromatography (HPLC) coupled with fluorescence detection (Flu). The optimised method exhibited a good precision level with relative standard deviation values between 1.2% and 5.7%. Quantification limits obtained for all of these considered compounds (between 0.1 and 7 ng L(-1)) were well below the limits recommended in the EU. The extraction yields for the different compounds obtained by IL-DLLME, ranged from 90.3% to 103.8%. Furthermore, high enrichment factors (301-346) were also achieved. The extraction efficiency of the optimised method is compared with that achieved by liquid-liquid extraction. Finally, the proposed method was successfully applied to the analysis of PAHs in real water samples (tap, bottled, fountain, well, river, rainwater, treated and raw wastewater).

  11. Applications of ionic liquids.

    PubMed

    Patel, Divia Dinesh; Lee, Jong-Min

    2012-06-01

    Ionic liquids have recently gained popularity in the scientific community owing to their special properties and characteristics. One of the reasons why ionic liquids have been termed "green solvents" is due to their negligible vapour pressure. Their use in electrochemical, biological and metal extraction applications is discussed. Wide research has been carried out for their use in batteries, solar panels, fuel cells, drug deliveries and biomass pretreatments. This work aims to consolidate the various findings from previous works in these areas.

  12. Simple Saucers

    ERIC Educational Resources Information Center

    Coy, Mary

    2008-01-01

    With standardized English Language Arts exams on the horizon, the author thought a game of Antonyms would provide not only a quick language arts activity for her sixth graders, but also a nice segue to an art lesson in contrast. In this article, she describes a project, a simple saucer on a pedestal base, which required students to demonstrate…

  13. Lattice models of ionic systems

    NASA Astrophysics Data System (ADS)

    Kobelev, Vladimir; Kolomeisky, Anatoly B.; Fisher, Michael E.

    2002-05-01

    A theoretical analysis of Coulomb systems on lattices in general dimensions is presented. The thermodynamics is developed using Debye-Hückel theory with ion-pairing and dipole-ion solvation, specific calculations being performed for three-dimensional lattices. As for continuum electrolytes, low-density results for simple cubic (sc), body-centered cubic (bcc), and face-centered cubic (fcc) lattices indicate the existence of gas-liquid phase separation. The predicted critical densities have values comparable to those of continuum ionic systems, while the critical temperatures are 60%-70% higher. However, when the possibility of sublattice ordering as well as Debye screening is taken into account systematically, order-disorder transitions and a tricritical point are found on sc and bcc lattices, and gas-liquid coexistence is suppressed. Our results agree with recent Monte Carlo simulations of lattice electrolytes.

  14. VOC and HAP recovery using ionic liquids

    SciTech Connect

    Michael R. Milota : Kaichang Li

    2007-05-29

    During the manufacture of wood composites, paper, and to a lesser extent, lumber, large amounts of volatile organic compounds (VOCs) such as terpenes, formaldehyde, and methanol are emitted to air. Some of these compounds are hazardous air pollutants (HAPs). The air pollutants produced in the forest products industry are difficult to manage because the concentrations are very low. Presently, regenerative thermal oxidizers (RTOs and RCOs) are commonly used for the destruction of VOCs and HAPs. RTOs consume large amounts of natural gas to heat air and moisture. The combustion of natural gas generates increased CO2 and NOx, which have negative implications for global warming and air quality. The aforementioned problems are addressed by an absorption system containing a room-temperature ionic liquid (RTIL) as an absorbent. RTILs are salts, but are in liquid states at room temperature. RTILs, an emerging technology, are receiving much attention as replacements for organic solvents in industrial processes with significant cost and environmental benefits. Some of these processes include organic synthesis, extraction, and metal deposition. RTILs would be excellent absorbents for exhausts from wood products facilities because of their unique properties: no measurable vapor pressure, high solubility of wide range of organic compounds, thermal stability to 200°C (almost 400°F), and immisciblity with water. Room temperature ionic liquids were tested as possible absorbents. Four were imidizolium-based and were eight phosphonium-based. The imidizolium-based ionic liquids proved to be unstable at the conditions tested and in the presence of water. The phosphonium-based ionic liquids were stable. Most were good absorbents; however, cleaning the contaminates from the ionic liquids was problematic. This was overcome with a higher temperature (120°C) than originally proposed and a very low pressure (1 kPa. Absorption trials were conducted with tetradecy

  15. The magic of aqueous solutions of ionic liquids: ionic liquids as a powerful class of catanionic hydrotropes†

    PubMed Central

    Cláudio, Ana Filipa M.; Neves, Márcia C.; Shimizu, Karina; Canongia Lopes, José N.; Freire, Mara G.; Coutinho, João A. P.

    2015-01-01

    Hydrotropes are compounds able to enhance the solubility of hydrophobic substances in aqueous media and therefore are widely used in the formulation of drugs, cleaning and personal care products. In this work, it is shown that ionic liquids are a new class of powerful catanionic hydrotropes where both the cation and the anion synergistically contribute to increase the solubility of biomolecules in water. The effects of the ionic liquid chemical structures, their concentration and the temperature on the solubility of two model biomolecules, vanillin and gallic acid were evaluated and compared with the performance of conventional hydrotropes. The solubility of these two biomolecules was studied in the entire composition range, from pure water to pure ionic liquids, and an increase in the solubility of up to 40-fold was observed, confirming the potential of ionic liquids to act as hydrotropes. Using dynamic light scattering, NMR and molecular dynamics simulations, it was possible to infer that the enhanced solubility of the biomolecule in the IL aqueous solutions is related to the formation of ionic-liquid–biomolecules aggregates. Finally, it was demonstrated that hydrotropy induced by ionic liquids can be used to recover solutes from aqueous media by precipitation, simply by using water as an anti-solvent. The results reported here have a significant impact on the understanding of the role of ionic liquid aqueous solutions in the extraction of value-added compounds from biomass as well as in the design of novel processes for their recovery from aqueous media. PMID:26379471

  16. Are Ionic Liquids Chemically Stable?

    PubMed

    Wang, Binshen; Qin, Li; Mu, Tiancheng; Xue, Zhimin; Gao, Guohua

    2017-02-27

    Ionic liquids have attracted a great deal of interest in recent years, illustrated by their applications in a variety of areas involved with chemistry, physics, biology, and engineering. Usually, the stabilities of ionic liquids are highlighted as one of their outstanding advantages. However, are ionic liquids really stable in all cases? This review covers the chemical stabilities of ionic liquids. It focuses on the reactivity of the most popular imidazolium ionic liquids at structural positions, including C2 position, N1 and N3 positions, and C4 and C5 positions, and decomposition on the imidazolium ring. Additionally, we discuss decomposition of quaternary ammonium and phosphonium ionic liquids and hydrolysis and nucleophilic reactions of anions of ionic liquids. The review aims to arouse caution on potential decomposition of ionic liquids and provides a guide for better utilization of ionic liquids.

  17. Full-color tunable photoluminescent ionic liquid crystals based on tripodal pyridinium, pyrimidinium, and quinolinium salts.

    PubMed

    Tanabe, Kana; Suzui, Yuko; Hasegawa, Miki; Kato, Takashi

    2012-03-28

    Color-tunable luminescent ionic liquid crystals have been designed as a new series of luminescent materials. To achieve tuning of emission colors, intramolecular charge transfer (ICT) character has been incorporated into tripodal molecules. A series of the compounds has three chromophores in each molecule, incorporated with both electron-donating moieties such as alkylaminobenzene and alkoxybenzene, and electron-accepting moieties such as pyridinium, pyrimidinium, and quinolinium parts. These C(3)-symmetrical molecules self-assemble into liquid-crystalline (LC) columnar (Col) structures over wide temperature ranges through nanosegregation between ionic moieties and nonionic aliphatic chains. Photoluminescent (PL) emissions of these tripodal molecules are observed in the visible region both in the self-assembled condensed states and in solutions. For example, a pyrimidinium salt with didodecylaminobenzene moieties exhibits yellowish orange emission (λ(em) = 586 nm in a thin film). Multicolor PL emissions are successfully achieved by simple tuning of changing electron-donating and electron-accepting moieties of the compounds, covering the visible region from blue-green to red. It has been revealed that ICT processes in the excited states and weak intermolecular interactions play important roles in the determination of the PL properties of the materials, by measurements of UV-vis absorption and emission spectra, fluorescence lifetimes, and PL quantum yields.

  18. Stretchable, transparent, ionic conductors.

    PubMed

    Keplinger, Christoph; Sun, Jeong-Yun; Foo, Choon Chiang; Rothemund, Philipp; Whitesides, George M; Suo, Zhigang

    2013-08-30

    Existing stretchable, transparent conductors are mostly electronic conductors. They limit the performance of interconnects, sensors, and actuators as components of stretchable electronics and soft machines. We describe a class of devices enabled by ionic conductors that are highly stretchable, fully transparent to light of all colors, and capable of operation at frequencies beyond 10 kilohertz and voltages above 10 kilovolts. We demonstrate a transparent actuator that can generate large strains and a transparent loudspeaker that produces sound over the entire audible range. The electromechanical transduction is achieved without electrochemical reaction. The ionic conductors have higher resistivity than many electronic conductors; however, when large stretchability and high transmittance are required, the ionic conductors have lower sheet resistance than all existing electronic conductors.

  19. Polymerizable ionic liquid crystals.

    PubMed

    Jazkewitsch, Olga; Ritter, Helmut

    2009-09-17

    Polymerizable vinylimidazolium ionic liquids (ILs) that contain mesogenic coumarin and biphenyl units, respectively, have been synthesized. The N-alkylation of N-vinylimidazole with bromoalkylated mesogenic units 7-(6-bromohexyloxy)coumarin (1) and 4,4'-bis(6-bromohexyloxy)biphenyl (2) was then carried out. The thermal behavior of the obtained ILs 3 and 4 was investigated by differential scanning calorimetry and polarizing optical microscopy. These measurements showed that the attached mesogenic units induce the self-assembly of ILs and, therefore, the occurrence of liquid crystalline phases. Subsequently, the ionic liquid crystals (ILCs) 3 and 4 were polymerized by a free-radical mechanism.

  20. Synthesis of task specific and reusable protic ionic liquids for one-pot multicomponent syntheses

    NASA Astrophysics Data System (ADS)

    Sardar, Sabahat; Wilfred, Cecilia Devi; Marc, Leveque Jean

    2016-11-01

    Protic ionic liquids (ILs) synthesized from 1-methylimidazole with 1,3-propane sultone and 1,4-butane sultone catalyzed Mannich reaction at 25 °C to afford Mannich bases in high yield (76%) and less time duration (20 min). Ionic liquids have been used as dual reagent i.e., as catalyst as well as solvent. Simple extraction by water separated ionic liquid from reaction mixture with 4 times recycling without any significant loss in activity.

  1. Ionic liquids in chemical engineering.

    PubMed

    Werner, Sebastian; Haumann, Marco; Wasserscheid, Peter

    2010-01-01

    The development of engineering applications with ionic liquids stretches back to the mid-1990s when the first examples of continuous catalytic processes using ionic liquids and the first studies of ionic liquid-based extractions were published. Ever since, the use of ionic liquids has seen tremendous progress in many fields of chemistry and engineering, and the first commercial applications have been reported. The main driver for ionic liquid engineering applications is to make practical use of their unique property profiles, which are the result of a complex interplay of coulombic, hydrogen bonding and van der Waals interactions. Remarkably, many ionic liquid properties can be tuned in a wide range by structural modifications at their cation and anion. This review highlights specific examples of ionic liquid applications in catalysis and in separation technologies. Additionally, the application of ionic liquids as working fluids in process machines is introduced.

  2. β-Lactam antibiotics. Spectroscopy and molecular orbital (MO) calculations . Part I: IR studies of complexation in penicillin-transition metal ion systems and semi-empirical PM3 calculations on simple model compounds

    NASA Astrophysics Data System (ADS)

    Kupka, Teobald

    1997-12-01

    IR studies were preformed to determine possible transition metal ion binding sites of penicillin. the observed changes in spectral position and shape of characteristic IR bands of cloxacillin in the presence of transition metal ions (both in solutions and in the solid state) indicate formation of M-L complexes with engagement of -COO - and/or -CONH- functional groups. The small shift of νCO towards higher frequencies rules out direct M-L interaction via β-lactam carbonyl. PM3 calculations on simple model compounds (substituted formamide, cyclic ketones, lactams and substituted monocyclic β-lactams) have been performed. All structures were fully optimized and the calculated bond lengths, angles, heats of formation and CO stretching frequencies were discussed to determine the β-lactam binding sites and to explain its susceptibility towards nucleophilic attack (hydrolysis in vitro) and biological activity. The relative changes of calculated values were critically compared with available experimental data and same correlation between structural parameters and in vivo activity was shown.

  3. Fast and simple screening for the simultaneous analysis of seven metabolites derived from five volatile organic compounds in human urine using on-line solid-phase extraction coupled with liquid chromatography-tandem mass spectrometry.

    PubMed

    Chiang, Wen-Chieh; Chen, Chao-Yu; Lee, Ting-Chen; Lee, Hui-Ling; Lin, Yu-Wen

    2015-01-01

    Recently, the International Agency for Research on cancer classified outdoor air pollution and particulate matter from outdoor air pollution as carcinogenic to humans (IARC Group 1), based on sufficient evidence of carcinogenicity in humans and experimental animals and strong mechanistic evidence. In particular, a wide variety of volatile organic compounds (VOCs) are volatized or released into the atmosphere and can become ubiquitous, as they originate from many different natural and anthropogenic sources, such as paints, pesticides, vehicle exhausts, cooking fumes, and tobacco smoke. Humans may be exposed to VOCs through inhalation, ingestion, or dermal contact, which may increase the risk of leukemia, birth defects, neurocognitive impairment, and cancer. Therefore, the focus of this study was the development of a simple, effective and rapid sample preparation method for the simultaneous determination of seven metabolites (6 mercaptic acids+t,t-muconic acid) derived from five VOCs (acrylamide, 1,3-butadiene, acrylonitrile, benzene, and xylene) in human urine by using automated on-line solid-phase extraction (SPE) coupled with liquid chromatography-electrospray tandem mass spectrometry (LC-MS/MS). An aliquot of each diluted urinary sample was directly injected into an autosampler through a trap column to reduce contamination, and then the retained target compounds were eluted by back-flush mode into an analytical column for separation. Negative electrospray ionization tandem mass spectrometry was utilized for quantification. The coefficients of correlation (r(2)) for the calibration curves were greater than 0.995. Reproducibility was assessed by the precision and accuracy of intra-day and inter-day precision, which showed results for coefficient of variation (CV) that were low 0.9 to 6.6% and 3.7 to 8.5%, respectively, and results for recovery that ranged from 90.8 to 108.9% and 92.1 to 107.7%, respectively. The limits of detection (LOD) and limits of

  4. Organic ionic salt draw solutions for osmotic membrane bioreactors.

    PubMed

    Bowden, Katie S; Achilli, Andrea; Childress, Amy E

    2012-10-01

    This investigation evaluates the use of organic ionic salt solutions as draw solutions for specific use in osmotic membrane bioreactors. Also, this investigation presents a simple method for determining the diffusion coefficient of ionic salt solutions using only a characterized membrane. A selection of organic ionic draw solutions underwent a desktop screening process before being tested in the laboratory and evaluated for performance using specific salt flux (reverse salt flux per unit water flux), biodegradation potential, and replenishment cost. Two of the salts were found to have specific salt fluxes three to six times lower than two commonly used inorganic draw solutions, NaCl and MgCl(2). All of the salts tested have organic anions with the potential to degrade in the bioreactor as a carbon source and aid in nutrient removal. Results demonstrate the potential benefits of organic ionic salt draw solutions over currently implemented inorganics in osmotic membrane bioreactor systems.

  5. The Effect of Ionic Strength on the Solubility of an Electrolyte

    ERIC Educational Resources Information Center

    Willey, Joan D.

    2004-01-01

    A simple experiment was conducted for studying and demonstrating visually and dramatically the effect of ionic strength on the solubility of an electrolyte is described. It is seen that the experiment visually illustrates the effect of ionic strength on electrolyte solubility by the appearance of the two solutions and by the difference in the…

  6. Ionic Channels in Thunderclouds

    NASA Astrophysics Data System (ADS)

    Losseva, T. V.; Fomenko, A. S.; Nemtchinov, I. V.

    2007-12-01

    We proceed to study the formation and propagation of ionic channels in thunderclouds in the framework of the model of the corona discharge wave propagation (Fomenko A.S., Losseva T.V., Nemtchinov I.V. The corona discharge waves in thunderclouds and formation of ionic channels // 2004 Fall Meeting. EOS Trans. AGU. 2004. V. 85. ¹ 47. Suppl. Abstract AE23A-0835.). In this model we proposed a hypothesis that the structure of a thundercloud becomes nonuniform due to corona discharge on the drops and ice particles and formation of ionic channels with higher conductivity than the surrounding air. When the onset strength of corona discharge becomes smaller than the electric field strength the corona discharge increases concentrations of ions in a small part of the cloud (a hot spot). An additional charge at opposite ends of the hot spot forms due to polarization process. The increased electric field initiates corona discharge in other parts of the cloud on ice particles and water drops with smaller sizes. The corona discharge front moves as a wave with the velocity of the order of ion drift and formes a highly conductive channel. We model this non-stationary problem with Poisson equation which is solved simultaneously with a simplified set of kinetic equations for ions, small charged particles and electrons (at high electric fields), including ionization due to electronic impact, attachment and formation of positive ions. By applying 3D numerical simulations we obtain the parameters of formed ionic channels with respect to onset electric fields both from large particles (in hot spot) and from small particles (surrounding hot spot), microscopic currents from particles with different sizes and the external electric field in the cloud. The interaction of ionic channels is also investigated. This work was supported by Russian Foundation of Basic Research (Project No 07-05-00998-à).

  7. Computationally Efficient Prediction of Ionic Liquid Properties.

    PubMed

    Chaban, Vitaly V; Prezhdo, Oleg V

    2014-06-05

    Due to fundamental differences, room-temperature ionic liquids (RTIL) are significantly more viscous than conventional molecular liquids and require long simulation times. At the same time, RTILs remain in the liquid state over a much broader temperature range than the ordinary liquids. We exploit the ability of RTILs to stay liquid at several hundred degrees Celsius and introduce a straightforward and computationally efficient method for predicting RTIL properties at ambient temperature. RTILs do not alter phase behavior at 600-800 K. Therefore, their properties can be smoothly extrapolated down to ambient temperatures. We numerically prove the validity of the proposed concept for density and ionic diffusion of four different RTILs. This simple method enhances the computational efficiency of the existing simulation approaches as applied to RTILs by more than an order of magnitude.

  8. Ionic model for highly compressed solid hydrogen

    NASA Astrophysics Data System (ADS)

    Yakub, E. S.

    2013-05-01

    We propose a simple ionic model for high-pressure conducting phase IV of solid hydrogen observed recently at room temperature. It is based on an assumption of dissociative ionization of hydrogen molecules 3H2=2H2(+)+2H(-) induced by high compression. The proposed model predicts the first order transition of molecular hydrogen solid into partly ionic conducting phase at megabar pressures and describes the temperature dependence of resistivity at room temperature. Its predictions are consistent with high temperature shock-compression experiments which exhibit conductivity of multiply shocked hydrogen. The location of phase transition line, the volume change, and the ionization degree in solid phase IV are estimated.

  9. Optimization of ionic conductivity in doped ceria

    PubMed Central

    Andersson, David A.; Simak, Sergei I.; Skorodumova, Natalia V.; Abrikosov, Igor A.; Johansson, Börje

    2006-01-01

    Oxides with the cubic fluorite structure, e.g., ceria (CeO2), are known to be good solid electrolytes when they are doped with cations of lower valence than the host cations. The high ionic conductivity of doped ceria makes it an attractive electrolyte for solid oxide fuel cells, whose prospects as an environmentally friendly power source are very promising. In these electrolytes, the current is carried by oxygen ions that are transported by oxygen vacancies, present to compensate for the lower charge of the dopant cations. Ionic conductivity in ceria is closely related to oxygen-vacancy formation and migration properties. A clear physical picture of the connection between the choice of a dopant and the improvement of ionic conductivity in ceria is still lacking. Here we present a quantum-mechanical first-principles study of the influence of different trivalent impurities on these properties. Our results reveal a remarkable correspondence between vacancy properties at the atomic level and the macroscopic ionic conductivity. The key parameters comprise migration barriers for bulk diffusion and vacancy–dopant interactions, represented by association (binding) energies of vacancy–dopant clusters. The interactions can be divided into repulsive elastic and attractive electronic parts. In the optimal electrolyte, these parts should balance. This finding offers a simple and clear way to narrow the search for superior dopants and combinations of dopants. The ideal dopant should have an effective atomic number between 61 (Pm) and 62 (Sm), and we elaborate that combinations of Nd/Sm and Pr/Gd show enhanced ionic conductivity, as compared with that for each element separately. PMID:16478802

  10. Method of purifying a gas stream using 1,2,3-triazolium ionic liquids

    SciTech Connect

    Luebke, David; Nulwala, Hunald; Tang, Chau

    2014-12-09

    A method for separating a target gas from a gaseous mixture using 1,2,3-triazolium ionic liquids is presented. Industrial effluent streams may be cleaned by removing carbon dioxide from the stream by contacting the effluent stream with a 1,2,3-triazolium ionic liquid compound.

  11. 1,10-Phenanthrolinium ionic liquid crystals.

    PubMed

    Cardinaels, Thomas; Lava, Kathleen; Goossens, Karel; Eliseeva, Svetlana V; Binnemans, Koen

    2011-03-01

    The 1,10-phenanthrolinium cation is introduced as a new building block for the design of ionic liquid crystals. 1,10-Phenanthroline, 5-methyl-1,10-phenanthroline, 5-chloro-1,10-phenanthroline, and 4,7-diphenyl-1,10-phenanthroline were quaternized by reaction with 1,3-dibromopropane or 1,2-dibromoethane. The resulting cations were combined with dodecyl sulfate or dioctyl sulfosuccinate anions. The influence of both the cation and anion type on the thermal behavior was investigated. Several of the complexes exhibit mesomorphic behavior, with smectic E phases for the dodecyl sulfate salts and smectic A phases for the dioctyl sulfosuccinate salts. Structural models for the packing of the 1,10-phenanthrolinium and anionic moieties in the liquid-crystalline phases are presented. The ionic compounds show fluorescence in the solid state and in solution.

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

    PubMed

    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.

  13. Combustible ionic liquids by design: is laboratory safety another ionic liquid myth?

    PubMed

    Smiglak, Marcin; Reichert, W Mathew; Holbrey, John D; Wilkes, John S; Sun, Luyi; Thrasher, Joseph S; Kirichenko, Kostyantyn; Singh, Shailendra; Katritzky, Alan R; Rogers, Robin D

    2006-06-28

    The non-flammability of ionic liquids (ILs) is often highlighted as a safety advantage of ILs over volatile organic compounds (VOCs), but the fact that many ILs are not flammable themselves does not mean that they are safe to use near fire and/or heat sources; a large group of ILs (including commercially available ILs) are combustible due to the nature of their positive heats of formation, oxygen content, and decomposition products.

  14. Ionic electroactive hybrid transducers

    NASA Astrophysics Data System (ADS)

    Akle, Barbar J.; Bennett, Matthew D.; Leo, Donald J.

    2005-05-01

    Ionic electroactive actuators have received considerable attention in the past ten years. Ionic electroactive polymers, sometimes referred to as artificial muscles, have the ability to generate large bending strain and moderate stress at low applied voltages. Typical types of ionic electroactive polymer transducers include ionic polymers, conducting polymers, and carbon nanotubes. Preliminary research combining multiple types of materials proved to enhance certain transduction properties such as speed of response, maximum strain, or quasi-static actuation. Recently it was demonstrated that ionomer-ionic liquid transducers can operate in air for long periods of time (>250,000 cycles) and showed potential to reduce or eliminate the back-relaxation issue associated with ionomeric polymers. In addition, ionic liquids have higher electrical stability window than those operated with water as the solvent thereby increasing the maximum strain that the actuator can produce. In this work, a new technique developed for plating metal particulates on the surface of ionomeric materials is applied to the development of hybrid transducers that incorporate carbon nanotubes and conducting polymers as electrode materials. The new plating technique, named the direct assembly process, consists of mixing a conducting powder with an ionomer solution. This technique has demonstrated improved response time and strain output as compared to previous methods. Furthermore, the direct assembly process is less costly to implement than traditional impregnation-reduction methods due to less dependence on reducing agents, it requires less time, and is easier to implement than other processes. Electrodes applied using this new technique of mixing RuO2 (surface area 45~65m2/g) particles and Nafion dispersion provided 5x the displacement and 10x the force compared to a transducer made with conventional methods. Furthermore, the study illustrated that the response speed of the transducer is optimized

  15. Ionic liquid-based one-step micellar extraction of multiclass polar compounds from hawthorn fruits by ultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry.

    PubMed

    Hu, Shuai-Shuai; Yi, Ling; Li, Xing-Ying; Cao, Jun; Ye, Li-Hong; Cao, Wan; Da, Jian-Hua; Dai, Han-Bin; Liu, Xiao-Juan

    2014-06-11

    An ionic liquid (IL)-based one-step micellar extraction procedure was developed for the extraction of multiclass polar analytes (protocatechuic acid, chlorogenic acid, epicatechin, hyperoside, isoquercitrin, quercetin) from hawthorn fruits and their determination using ultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UHPLC-Q-TOF/MS). Compared to conventional organic solvent extractions, this newly proposed method was much easier, more sensitive, environmentally friendly, and effective as well. Several important parameters influencing the micellar extraction efficiency are discussed, such as selection of ILs, surfactant concentration, and extraction time. Under the optimal conditions, good linearity was achieved for each analyte with correlation coefficients (r(2)) ranging from 0.9934 to 0.9999, and the recovery values ranged from 89.3 to 106% with relative standard deviations lower than 5.5%. Results suggest that the IL-based one-step micellar extraction could be an alternative and promising means in future food analysis.

  16. Piperidinium, piperazinium and morpholinium ionic liquid crystals.

    PubMed

    Lava, Kathleen; Binnemans, Koen; Cardinaels, Thomas

    2009-07-16

    Piperidinium, piperazinium and morpholinium cations have been used for the design of ionic liquid crystals. These cations were combined with several types of anions, namely bromide, tetrafluoroborate, hexafluorophosphate, dodecylsulfate, bis(trifluoromethylsulfonyl)imide, dioctylsulfosuccinate, dicyclohexylsulfosuccinate, and dihexylsulfosuccinate. For the bromide salts of piperidinium containing one alkyl chain, the chain length was varied, ranging from 8 to 18 carbon atoms (n = 8, 10, 12, 14, 16, 18). The compounds show a rich mesomorphic behavior. High-ordered smectic phases (crystal smectic E and T phases), smectic A phases, and hexagonal columnar phases were observed, depending on the type of cation and anion. The morpholinium compounds with sulfosuccinate anions showed hexagonal columnar phases at room temperature and a structural model for the self-assembly of these morpholinium compounds into hexagonal columnar phases is proposed.

  17. Super ionic conductive glass

    DOEpatents

    Susman, S.; Volin, K.J.

    Described is an ionically conducting glass for use as a solid electrolyte in a power or secondary cell containing an alkali metal-containing anode and a cathode separated by an alkali metal ion conducting glass having an ionic transference number of unity and the general formula: A/sub 1 + x/D/sub 2-x/3/Si/sub x/P/sub 3 - x/O/sub 12 - 2x/3/, wherein A is a network modifier for the glass and is an alkali metal of the anode, D is an intermediate for the glass and is selected from the class consisting of Zr, Ti, Ge, Al, Sb, Be, and Zn and X is in the range of from 2.25 to 3.0. Of the alkali metals, Na and Li are preferred and of the intermediate, Zr, Ti and Ge are preferred.

  18. Super ionic conductive glass

    DOEpatents

    Susman, Sherman; Volin, Kenneth J.

    1984-01-01

    An ionically conducting glass for use as a solid electrolyte in a power or secondary cell containing an alkali metal-containing anode and a cathode separated by an alkali metal ion conducting glass having an ionic transference number of unity and the general formula: A.sub.1+x D.sub.2-x/3 Si.sub.x P.sub.3-x O.sub.12-2x/3, wherein A is a network modifier for the glass and is an alkali metal of the anode, D is an intermediate for the glass and is selected from the class consisting of Zr, Ti, Ge, Al, Sb, Be, and Zn and X is in the range of from 2.25 to 3.0. Of the alkali metals, Na and Li are preferred and of the intermediate, Zr, Ti and Ge are preferred.

  19. PALLADIUM-CATALYZED OXIDATION OF STYRENE AND ALKENES IN PRESENCE OF IONIC LIQUIDS (WACKER REACTION)

    EPA Science Inventory

    The use of ionic liquids in various synthetic transformations is gaining significance due to the enhanced reaction rates, potential for recycling and compatibility with various organic compounds and organometallic catalysts. Palladium-catalyzed oxidation of styrene and other alk...

  20. Dual active ionic liquids and organic salts for inhibition of microbially influenced corrosion.

    PubMed

    Seter, Marianne; Thomson, Melanie J; Stoimenovski, Jelena; MacFarlane, Douglas R; Forsyth, Maria

    2012-06-18

    We describe a series of novel compounds designed to combat the bacterial growth that leads to microbially induced corrosion on steel in the marine environment. A synergistic effect of the ionic components in these dual active organic salts is demonstrated.

  1. Catalytic conversion of cellulose to chemicals in ionic liquid.

    PubMed

    Tao, Furong; Song, Huanling; Chou, Lingjun

    2011-01-03

    A simple and effective route for the production of 5-hydroxymethyl furfural (HMF) and furfural from microcrystalline cellulose (MCC) has been developed. CoSO(4) in an ionic liquid, 1-(4-sulfonic acid) butyl-3-methylimidazolium hydrogen sulfate (IL-1), was found to be an efficient catalyst for the hydrolysis of cellulose at 150°C, which led to 84% conversion of MCC after 300min reaction time. In the presence of a catalytic amount of CoSO(4), the yields of HMF and furfural were up to 24% and 17%, respectively; a small amount of levulinic acid (LA) and reducing sugars (8% and 4%, respectively) were also generated. Dimers of furan compounds were detected as the main by-products through HPLC-MS, and with the help of mass spectrometric analysis, the components of gas products were methane, ethane, CO, CO(2,) and H(2). A mechanism for the CoSO(4)-IL-1 hydrolysis system was proposed and IL-1 was recycled for the first time, which exhibited favorable catalytic activity over five repeated runs. This catalytic system may be valuable to facilitate energy-efficient and cost-effective conversion of biomass into biofuels and platform chemicals.

  2. Protic pharmaceutical ionic liquids and solids: aspects of protonics.

    PubMed

    Stoimenovski, Jelena; Dean, Pamela M; Izgorodina, Ekaterina I; MacFarlane, Douglas R

    2012-01-01

    A series of new protic compounds based on active pharmaceutical ingredients have been synthesised and characterised. Some of the salts synthesised produced ionic liquids, while others that were associated with rigid molecular structures tended to produce high melting points. The "protonic" behaviour of these compounds was found to be a major determinant of their properties. Indicator studies, FTIR-ATR and transport properties (Walden plot) were used to probe the extent of proton transfer and ion association in these ionic liquids. While proton transfer was shown to have taken place in all cases, the Walden plot indicated strong ion association in the primary amine based examples due to hydrogen bonding. This was further explored via crystal structures of related compounds, which showed that extended hydrogen bonded clusters tend to form in these salts. These clusters may dictate membrane transport properties of these compounds in vivo.

  3. Vibrational Spectroscopy of Ionic Liquids.

    PubMed

    Paschoal, Vitor H; Faria, Luiz F O; Ribeiro, Mauro C C

    2017-01-04

    Vibrational spectroscopy has continued use as a powerful tool to characterize ionic liquids since the literature on room temperature molten salts experienced the rapid increase in number of publications in the 1990's. In the past years, infrared (IR) and Raman spectroscopies have provided insights on ionic interactions and the resulting liquid structure in ionic liquids. A large body of information is now available concerning vibrational spectra of ionic liquids made of many different combinations of anions and cations, but reviews on this literature are scarce. This review is an attempt at filling this gap. Some basic care needed while recording IR or Raman spectra of ionic liquids is explained. We have reviewed the conceptual basis of theoretical frameworks which have been used to interpret vibrational spectra of ionic liquids, helping the reader to distinguish the scope of application of different methods of calculation. Vibrational frequencies observed in IR and Raman spectra of ionic liquids based on different anions and cations are discussed and eventual disagreements between different sources are critically reviewed. The aim is that the reader can use this information while assigning vibrational spectra of an ionic liquid containing another particular combination of anions and cations. Different applications of IR and Raman spectroscopies are given for both pure ionic liquids and solutions. Further issues addressed in this review are the intermolecular vibrations that are more directly probed by the low-frequency range of IR and Raman spectra and the applications of vibrational spectroscopy in studying phase transitions of ionic liquids.

  4. Liquid clathrate formation in ionic liquid-aromatic mixtures.

    PubMed

    Holbrey, John D; Reichert, W Matthew; Nieuwenhuyzen, Mark; Sheppard, Oonagh; Hardacre, Christopher; Rogers, Robin D

    2003-02-21

    1-Alkyl-3-methylimidazolium containing ionic liquids with hexafluorophosphate, bis(trifyl)imide, tetrafluoroborate, and chloride anions form liquid clathrates when mixed with aromatic hydrocarbons; in the system 1,3-dimethylimidazolium hexafluorophosphate-benzene, the aromatic solute could be trapped in the solid state forming a crystalline 2:1 inclusion compound.

  5. Preparation of AgX (X = Cl, I) nanoparticles using ionic liquids.

    PubMed

    Rodil, Eva; Aldous, Leigh; Hardacre, Christopher; Lagunas, M Cristina

    2008-03-12

    Nanoparticles of silver halides have been prepared by mixing silver halide powder with a single liquid phase consisting of an ionic liquid, isooctane, n-decanol and water. Much higher nanoparticle concentrations may be formed with ionic liquids using this new simple method than are found with conventionally applied surfactants. This method also emphasizes the applicability of ionic liquids as versatile components in microemulsions and as solvents for the synthesis of nanomaterials. The effect on the nanoparticles of changing the composition of the liquid mixtures and the nature of the ionic liquid is analysed. High nanoparticle concentrations were only found with chloride based ionic liquids, indicating the importance of the ionic liquid anion in the mechanism of the reaction.

  6. Preparation of AgX (X = Cl, I) nanoparticles using ionic liquids

    NASA Astrophysics Data System (ADS)

    Rodil, Eva; Aldous, Leigh; Hardacre, Christopher; Lagunas, M. Cristina

    2008-03-01

    Nanoparticles of silver halides have been prepared by mixing silver halide powder with a single liquid phase consisting of an ionic liquid, isooctane, n-decanol and water. Much higher nanoparticle concentrations may be formed with ionic liquids using this new simple method than are found with conventionally applied surfactants. This method also emphasizes the applicability of ionic liquids as versatile components in microemulsions and as solvents for the synthesis of nanomaterials. The effect on the nanoparticles of changing the composition of the liquid mixtures and the nature of the ionic liquid is analysed. High nanoparticle concentrations were only found with chloride based ionic liquids, indicating the importance of the ionic liquid anion in the mechanism of the reaction.

  7. TETRAALKYLPHOSPHONIUM POLYOXOMETALATES AS NOVEL IONIC LIQUIDS.

    SciTech Connect

    DIETZ,M.L.; RICKERT, P.G.; ANTONIO, M.R.; FIRESTONE, M.A.; WISHART, J.F.; SZREDER, T.

    2007-11-30

    The pairing of a Lindqvist or Keggin polyoxometalate (POM) anion with an appropriate tetraalkylphosphonium cation, [R{sub 3}R{prime}P]{sup +}, has been shown to yield an original family of ionic liquids (POM-ILs), among them salts liquid at or near ambient temperature. The physicochemical properties of several such 'inorganic liquids', in particular their thermal properties, suggests the possible application of these compounds as robust, thermally-stable solvents for liquid-liquid extraction. A preliminary evaluation of the potential of POM-ILs in this application is presented.

  8. Graphene-ionic liquid composites

    DOEpatents

    Aksay, Ilhan A.; Korkut, Sibel; Pope, Michael; Punckt, Christian

    2016-11-01

    Method of making a graphene-ionic liquid composite. The composite can be used to make elec-trodes for energy storage devices, such as batteries and supercapacitors. Dis-closed and claimed herein is method of making a graphene-ionic liquid com-posite, comprising combining a graphene source with at least one ionic liquid and heating the combination at a temperature of at least about 130 .degree. C.

  9. Design of Energetic Ionic Liquids

    DTIC Science & Technology

    2009-05-12

    effectiveness of the FMO method in both providing accurate results and reducing computational requirements, timings were performed for the ionic liquid ...Technical Paper 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Design of Energetic Ionic Liquids 5b. GRANT NUMBER 5c...Design of Energetic Ionic Liquids challenge project is to address several key technical issues and challenges associated with the characterization

  10. Low-dimensional compounds containing bioactive ligands. Part VIII: DNA interaction, antimicrobial and antitumor activities of ionic 5,7-dihalo-8-quinolinolato palladium(II) complexes with K(+) and Cs(+) cations.

    PubMed

    Farkasová, Veronika; Drweesh, Sayed Ali; Lüköová, Andrea; Sabolová, Danica; Radojević, Ivana D; Čomić, Ljiljana R; Vasić, Sava M; Paulíková, Helena; Fečko, Stanislav; Balašková, Tatiana; Vilková, Mária; Imrich, Ján; Potočňák, Ivan

    2017-02-01

    Starting from well-defined NH2(CH3)2[PdCl2(XQ)] complexes, coordination compounds of general formula Cat[PdCl2(XQ)] have been prepared by cationic exchange of NH2(CH3)2(+) and Cat cations, where XQ are biologically active halogen derivatives of quinolin-8-ol (5-chloro-7-iodo-quinolin-8-ol (CQ), 5,7-dibromo-quinolin-8-ol (dBrQ) and 5,7-dichloro-quinolin-8-ol (dClQ)) and Cat is K(+) or Cs(+). The cation exchange of all prepared complexes, K[PdCl2(CQ)] (1), K[PdCl2(dClQ)] (2), K[PdCl2(dBrQ)] (3), Cs[PdCl2(CQ)] (4), Cs[PdCl2(dClQ)] (5) and Cs[PdCl2(dBrQ)] (6) was approved using IR spectroscopy, their structures in DMSO solution were elucidated by one- and two-dimensional NMR experiments, whereas their stability in solution was verified by UV-VIS spectroscopy. Interaction of complexes to ctDNA was investigated using UV-VIS and fluorescence emission spectroscopy. The minimum inhibitory concentration and the minimum microbicidal concentration values were detected against 15 bacterial strains and 4 yeast strains to examine the antimicrobial activity for the complexes. The in vitro antitumor properties of the complexes were studied by testing the complexes on leukemic cell line L1210, ovarian cancer cell line A2780 and non-cancerous cell line HEK293. The majority of the prepared compounds exhibited moderate antimicrobial and very high cytotoxic activity.

  11. The evaporation study of silicon-containing ionic liquid

    NASA Astrophysics Data System (ADS)

    Chilingarov, Norbert S.; Medvedev, Artem A.; Deyko, Grigoriy S.; Kustov, Leonid M.; Chernikova, Elena A.; Glukhov, Lev M.; Polyakova, Marina V.; Ioutsi, Vitaliy A.; Markov, Vitaliy Yu.; Sidorov, Lev N.

    2016-07-01

    1,2-Dimethyl-3-(1‧,1‧,3‧,3‧-tetramethyl-3‧-phenyldisiloxanyl)methylimidazolium bis(trifluoromethanesulfonyl)amide ([PhC5OSi2MMIm+][Tf2N-]) is the first silicon-containing ionic liquid which was characterized with the vaporization enthalpy, (138.5 ± 1.8) kJ mol-1, and saturated vapor pressure, ln(p/Pa) = -(16656 ± 219)/(T/K) + (30.69 ± 0.92). This compound is a unique ionic liquid giving ions, retaining both cationic and anionic portions, in the electron impact ionization (EI) mass spectrum.

  12. Predictive thermodynamics for ionic solids and liquids.

    PubMed

    Glasser, Leslie; Jenkins, H Donald Brooke

    2016-08-21

    The application of thermodynamics is simple, even if the theory may appear intimidating. We describe tools, developed over recent years, which make it easy to estimate often elusive thermodynamic parameter values, generally (but not exclusively) for ionic materials, both solid and liquid, as well as for their solid hydrates and solvates. The tools are termed volume-based thermodynamics (VBT) and thermodynamic difference rules (TDR), supplemented by the simple salt approximation (SSA) and single-ion values for volume, Vm, heat capacity, , entropy, , formation enthalpy, ΔfH°, and Gibbs formation energy, ΔfG°. These tools can be applied to provide values of thermodynamic and thermomechanical properties such as standard enthalpy of formation, ΔfH°, standard entropy, , heat capacity, Cp, Gibbs function of formation, ΔfG°, lattice potential energy, UPOT, isothermal expansion coefficient, α, and isothermal compressibility, β, and used to suggest the thermodynamic feasibility of reactions among condensed ionic phases. Because many of these methods yield results largely independent of crystal structure, they have been successfully extended to the important and developing class of ionic liquids as well as to new and hypothesised materials. Finally, these predictive methods are illustrated by application to K2SnCl6, for which known experimental results are available for comparison. A selection of applications of VBT and TDR is presented which have enabled input, usually in the form of thermodynamics, to be brought to bear on a range of topical problems. Perhaps the most significant advantage of VBT and TDR methods is their inherent simplicity in that they do not require a high level of computational expertise nor expensive high-performance computation tools - a spreadsheet will usually suffice - yet the techniques are extremely powerful and accessible to non-experts. The connection between formula unit volume, Vm, and standard thermodynamic parameters represents a

  13. Design and Evaluation of Ionic Liquids as Novel CO2 Absorbents

    SciTech Connect

    Edward J. Maginn

    2006-01-12

    Progress from the fourth quarter 2005 activity on the project ''Design and Evaluation of Ionic Liquids as Novel CO{sub 2} Absorbents'' is provided. Major activities in three areas are reported: compound synthesis, property measurement and molecular modeling. Last quarter we reported the first ever experimental measurement of SO{sub 2} solubility in an ionic liquid. We showed that SO{sub 2} was very soluble in the ionic liquid 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([hmim][Tf{sub 2}N]). This quarter, we have measured SO{sub 2} solubility in two more ionic liquids: 1-hexyl-3-methylpyridinium bis(trifluoromethanesulfonyl)imide ([hmpy][Tf{sub 2}N]) and 1-hexyl-3-methylimidazolium lactate ([hmim][lactate]). As with [hmim][Tf{sub 2}N], we find very high solubility of SO{sub 2} in these ionic liquids, but the lactate compounds shows the highest affinity for SO{sub 2} at low pressure. CO{sub 2} solubility was measured in three new compounds: [boronium][Tf{sub 2}N], 1-hexyl-3-methylimidazolium acesulfumate ([hmim][ace]), and 1-hexyl-3-methylimidazolium saccharinate ([hmim][sac]). We find relatively poor solubility of CO{sub 2} in the latter two compounds, and solubility comparable to [hmim][Tf{sub 2}N] in the boronium compound. We also synthesized four new ionic liquids this quarter and continued refinement of our molecular simulation technique for measuring gas solubility.

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

    PubMed

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

    2014-12-26

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

  15. Ionic liquids as surfactants

    NASA Astrophysics Data System (ADS)

    Smirnova, N. A.; Safonova, E. A.

    2010-10-01

    Problems of self-assembling in systems containing ionic liquids (ILs) are discussed. Main attention is paid to micellization in aqueous solutions of dialkylimidazolium ILs and their mixtures with classical surfactants. Literature data are reviewed, the results obtained by the authors and co-workers are presented. Thermodynamic aspects of the studies and problems of molecular-thermodynamic modeling receive special emphasis. It is shown that the aggregation behavior of dialkylimidazolium ILs is close to that of alkyltrimethylammonium salts (cationic surfactants) though ILs have a higher ability to self-organize, especially as it concerns long-range ordering. Some aspects of ILs applications are outlined where their common features with classical surfactants and definite specificity are of value.

  16. Intermetallic Compounds

    NASA Astrophysics Data System (ADS)

    Takagiwa, Y.; Matsuura, Y.; Kimura, K.

    2014-06-01

    We have focused on the binary narrow-bandgap intermetallic compounds FeGa3 and RuGa3 as thermoelectric materials. Their crystal structure is FeGa3-type (tetragonal, P42/ mnm) with 16 atoms per unit cell. Despite their simple crystal structure, their room temperature thermal conductivity is in the range 4-5-W-m-1-K-1. Both compounds have narrow-bandgaps of approximately 0.3-eV near the Fermi level. Because their Seebeck coefficients are quite large negative values in the range 350-<-| S 373K|-<-550- μV-K-1 for undoped samples, it should be possible to obtain highly efficient thermoelectric materials both by adjusting the carrier concentration and by reducing the thermal conductivity. Here, we report the effects of doping on the thermoelectric properties of FeGa3 and RuGa3 as n and p-type materials. The dimensionless figure of merit, ZT, was significantly improved by substitution of Sn for Ga in FeGa3 (electron-doping) and by substitution of Zn for Ga in RuGa3 (hole-doping), mainly as a result of optimization of the electronic part, S 2 σ.

  17. Half-cell potentials of semiconductive simple binary sulphides in aqueous solution

    USGS Publications Warehouse

    Sato, M.

    1966-01-01

    Theoretical consideration of the charge-transfer mechanism operative in cells with an electrode of a semiconductive binary compound leads to the conclusion that the half-cell potential of such a compound is not only a function of ionic activities in the electrolytic solution, but also a function of the activities of the component elements in the compound phase. The most general form of the electrode equation derived for such a compound with a formula MiXj which dissociates into Mj+ and Xi- ions in aqueous solution is. EMiXj = EMiXj0 + R T 2 ij ln [ (sua Mj+)aqi ?? (suaX)jMiXj/ (suaXi-)aqj ?? (suaM)iMiXj],. where. EMiXj0 = 1 2(EM,Mj+0 + EXi-,X). The equation can be modified to other forms. When applied to semiconductive simple binary sulphides, these equations appear to give better descriptions of the observed electrode potentials of such sulphides than any other proposed equations. ?? 1966.

  18. Design of guanidinium ionic liquid based microwave-assisted extraction for the efficient extraction of Praeruptorin A from Radix peucedani.

    PubMed

    Ding, Xueqin; Li, Li; Wang, Yuzhi; Chen, Jing; Huang, Yanhua; Xu, Kaijia

    2014-12-01

    A series of novel tetramethylguanidinium ionic liquids and hexaalkylguanidinium ionic liquids have been synthesized based on 1,1,3,3-tetramethylguanidine. The structures of the ionic liquids were confirmed by (1)H NMR spectroscopy and mass spectrometry. A green guanidinium ionic liquid based microwave-assisted extraction method has been developed with these guanidinium ionic liquids for the effective extraction of Praeruptorin A from Radix peucedani. After extraction, reversed-phase high-performance liquid chromatography with UV detection was employed for the analysis of Praeruptorin A. Several significant operating parameters were systematically optimized by single-factor and L9 (3(4)) orthogonal array experiments. The amount of Praeruptorin A extracted by [1,1,3,3-tetramethylguanidine]CH2CH(OH)COOH is the highest, reaching 11.05 ± 0.13 mg/g. Guanidinium ionic liquid based microwave-assisted extraction presents unique advantages in Praeruptorin A extraction compared with guanidinium ionic liquid based maceration extraction, guanidinium ionic liquid based heat reflux extraction and guanidinium ionic liquid based ultrasound-assisted extraction. The precision, stability, and repeatability of the process were investigated. The mechanisms of guanidinium ionic liquid based microwave-assisted extraction were researched by scanning electron microscopy and IR spectroscopy. All the results show that guanidinium ionic liquid based microwave-assisted extraction has a huge potential in the extraction of bioactive compounds from complex samples.

  19. Ionic colloidal crystals: Ordered, multicomponent structures via controlled heterocoagulation.

    PubMed

    Maskaly, Garry R; García, R Edwin; Carter, W Craig; Chiang, Yet-Ming

    2006-01-01

    We propose a new type of ordered colloid, the "ionic colloidal crystal" (ICC), which is stabilized by attractive electrostatic interactions analogous to those in atomic ionic materials. The rapid self-organization of colloids via this method should result in a diversity of orderings that are analogous to ionic compounds. Most of these complex structures would be difficult to produce by other methods. We use a Madelung summation approach to evaluate the conditions where ICC's are thermodynamically stable. Using this model, we compare the relative electrostatic energies of various structures showing that the regions of ICC stability are determined by two dimensionless parameters representing charge balance and the spatial extent of the electrostatic interactions. Parallels and distinctions between ICC's and classical ionic crystals are discussed. Monte Carlo simulations are utilized to examine the glass transition and melting temperatures, between which crystallization can occur, of a model system having the rocksalt structure. These tools allow us to make a first-order prediction of the experimentally accessible regions of surface charge, particle size, ionic strength, and temperature where ICC formation is probable.

  20. Hydrogen bonding in ionic liquids.

    PubMed

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

    2015-03-07

    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

  1. Nanostructured liquid crystals combining ionic and electronic functions.

    PubMed

    Yazaki, Sanami; Funahashi, Masahiro; Kagimoto, Junko; Ohno, Hiroyuki; Kato, Takashi

    2010-06-09

    New molecular materials combining ionic and electronic functions have been prepared by using liquid crystals consisting of terthiophene-based mesogens and terminal imidazolium groups. These liquid crystals show thermotropic smectic A phases. Nanosegregation of the pi-conjugated mesogens and the ionic imidazolium moieties leads to the formation of layered liquid-crystalline (LC) structures consisting of 2D alternating pathways for electronic charges and ionic species. These nanostructured materials act as efficient electrochromic redox systems that exhibit coupled electrochemical reduction and oxidation in the ordered bulk states. For example, compound 1 having the terthienylphenylcyanoethylene mesogen and the imidazolium triflate moiety forms the smectic LC nanostructure. Distinct reversible electrochromic responses are observed for compound 1 without additional electrolyte solution on the application of double-potential steps between 0 and 2.5 V in the smectic A phase at 160 degrees C. In contrast, compound 2 having a tetrafluorophenylterthiophene moiety and compound 3 having a phenylterthiophene moiety exhibit irreversible cathodic reduction and reversible anodic oxidation in the smectic A phases. The use of poly(3,4-ethylenedioxythiophene)-poly(4-styrene sulfonate) (PEDOT-PSS) as an electron-accepting layer on the cathode leads to the distinct electrochromic responses for 2 and 3. These results show that new self-organized molecular redox systems can be built by nanosegregated pi-conjugated liquid crystals containing imidazolium moieties with and without electroactive thin layers on the electrodes.

  2. Ionic Conductivity of Nanostructured Block Copolymer and Ionic Liquid Membranes

    NASA Astrophysics Data System (ADS)

    Hoarfrost, Megan L.; Virgili, Justin M.; Segalman, Rachel A.

    2010-03-01

    Block copolymer and ionic liquid mixtures are of interest for creating ionically conductive, thermally stable, and nanostructured membranes. For mixtures of poly(styrene-b-2-vinylpyridine) (S2VP) and the ionic liquid bis(trifluoromethanesulfonyl)imide ([Im][TFSI]), nanostructured ion-conducting domains are formed due to [Im][TFSI] selectively residing in the P2VP domains of the block copolymer. The dependence of ionic conductivity on temperature, ionic liquid loading, and volume fraction of PS in the neat block copolymer was investigated for membranes with the matrix phase being P2VP/[Im][TFSI]. It was determined that the temperature dependence of conductivity follows the Vogel-Tamman-Fulcher equation, with the activation energy determined by the ratio of [Im][TFSI] to 2VP monomers. The overall weight fraction of [Im][TFSI] in the mixtures, however, is the dominating factor determining conductivity, regardless of PS volume fraction. The insight gained from this work will be important for further investigation into the effect on the ion transport properties of ionic liquids when confined to minority nanostructured domains.

  3. Chiral discrimination by ionic liquids: impact of ionic solutes.

    PubMed

    Brown, Christopher J; Hopkins, Todd A

    2015-04-01

    Chiral ionic liquids hold promise in many asymmetric applications. This study explores the impact of ionic solutes on the chiral discrimination of five amino acid methyl ester-based ionic liquids, including L- and D-alanine methyl ester, L-proline methyl ester, L-leucine methyl ester, and L-valine methyl ester cations combined with bis(trifluoromethanesulfonimide) anion. Circularly polarized luminescence spectroscopy was used to study the chiral discrimination by measuring the racemization equilibrium of a dissymmetric europium complex, Eu(dpa)3(3-) (where dpa = 2,6-pyridinedicarboxylate). The chiral discrimination measured was dependent on the concentration of Eu(dpa)3(3-) and this concentration-dependence was different in each of the ionic liquids. Ionic liquids with L-leucine methyl ester and L-valine methyl ester even switched enantiomeric preference based on the solute concentration. Changing the cation of the Eu(dpa)3(3-) salt from tetrabutylammonium to tetramethylammonium ion also affected the chiral discrimination demonstrated by the ionic liquids.

  4. Polymerizable ionic liquid with state of the art transport properties.

    PubMed

    Jeremias, Sebastian; Kunze, Miriam; Passerini, Stefano; Schönhoff, Monika

    2013-09-12

    The physicochemical properties of diallyldimethylammonium-bis(trifluoromethanesulfonyl)imide (DADMATFSI) and its binary mixture with LiTFSI are presented herein, also showing this novel compound as a polymerizable room temperature ionic liquid with excellent transport properties for Li(+) ions. In particular, results of pulsed field gradient (PFG)-NMR diffusion experiments and impedance measurements show that DADMATFSI exhibits state of the art properties of ionic liquids. Similar ionic diffusion coefficients and a similarly high conductivity as seen in the benchmark compound N-butyl-N-methylpyrrolidinium-bis(trifluoromethanesulfonyl)imide (PYR14TFSI) are observed. In accordance, the Li transference number in the binary mixture matches the trend seen for PYR14TFSI-LiTFSI mixtures. In addition to these impressive properties as ionic liquid, DADMATFSI was polymerized by UV treatment. The polymerization is demonstrated and the ion conducting properties of the resulting gel polymer electrolyte are investigated, showing that DADMATFSI can be transformed into an ionogel and may have applications where polymerization is desirable.

  5. Theoretical Study of Renewable Ionic Liquids in the Pure State and with Graphene and Carbon Nanotubes.

    PubMed

    García, Gregorio; Atilhan, Mert; Aparicio, Santiago

    2015-09-17

    The N-ethyl-N-(furan-2-ylmethyl)ethanaminium dihydrogen phosphate ionic liquid was studied as a model of ionic liquids which can be produced from totally renewable sources. A computational study using both molecular dynamics and density functional theory methods was carried out. The properties, structuring, and intermolecular interactions (hydrogen bonding) of this fluid in the pure state were studied as a function of pressure and temperature. Likewise, the adsorption on graphene and the confinement between graphene sheets was also studied. The solvation of single walled carbon nanotubes in the selected ionic liquid was analyzed together with the behavior of ions confined inside these nanotubes. The reported results show remarkable properties for this fluid, which show that many of the most relevant properties of ionic liquids and their ability to interact with carbon nanosystems may be maintained and even improved using new families of renewable compounds instead of classic types of ionic liquids with worse environmental, toxicological, and economical profiles.

  6. Altitudinal, diurnal and latitudinal dependences for ionic concentrations formed by corpuscular fluxes in the stratosphere and mesosphere

    NASA Technical Reports Server (NTRS)

    Bragin, Y. A.

    1975-01-01

    On the basis of over 15 rocket measurements of ionic concentrations below 80 km, the height, daily and latitudinal dependences between positive ionic concentrations and cosmic ray intensity below 60 km as well as between ionic concentrations and corpuscular streams within the 60-80 km altitude range are compared. It is shown that ionic concentration and cosmic ray intensity below 60 km at night are likely to be interrelated, in conformity with Chapman's theory of the simple layer. In daytime, all phenomena are aggravated by photodetachment and ion exchange reactions with the participation of ozone. Between 60-80 km, besides ordinary cosmic rays, there must exist an additional corpuscular stream.

  7. Advantages of ion-based mole fractions for describing phase equilibria in ionic liquids: application to gas solubility.

    PubMed

    Longinotti, María Paula; Alvarez, Jorge L; Japas, M Laura

    2009-03-19

    Despite the obvious ionic character of ionic liquids (ILs), previous studies of phase equilibria in these media were formulated implicitly assuming a "molecular" behavior of the ionic solvent. In this work, a more appropriate thermodynamic treatment is applied to describe the solubility of gases in ILs. According to our results, if the concentration is expressed on an ionic basis, solutions of simple gases in ILs display rather small deviations from ideal behavior in wide composition ranges, whereas deviations are larger when the solvent is considered as an anion-cation pair. The present thermodynamic formulation also accounts for the observed solid-liquid phase equilibria of molecular and IL binary mixtures.

  8. Phytoremediation of Ionic and Methyl Mercury Pollution

    SciTech Connect

    Meagher, Richard B.

    2005-06-01

    control the chemical speciation, electrochemical state, transport, and aboveground binding of mercury in order to manage this toxicant. To advance this mercury phytoremediation strategy, our planned research focuses on the following Specific Aims: (1) to increase the transport of mercury to aboveground tissue; (2) to identify small mercury binding peptides that enhance hyperaccumulation aboveground; (3) to test the ability of multiple genes acting together to enhance resistance and hyperaccumulation; (4) to construct a simple molecular system for creating male/female sterility, allowing engineered grass, shrub, and tree species to be released indefinitely at contaminated sites; (5) to test the ability of transgenic cottonwood and rice plants to detoxify ionic mercury and prevent methylmercury release from contaminated sediment; and (6) to initiate field testing with transgenic cottonwood and rice for the remediation of methylmercury and ionic mercury. The results of these experiments will enable the phytoremediation of methyl- and ionic mercury by a wide spectrum of deep-rooted, fast-growing plants adapted to diverse environments. We have made significant progress on all six of these specific aims as summarized below.

  9. Ionic thermoelectric gating organic transistors

    PubMed Central

    Zhao, Dan; Fabiano, Simone; Berggren, Magnus; Crispin, Xavier

    2017-01-01

    Temperature is one of the most important environmental stimuli to record and amplify. While traditional thermoelectric materials are attractive for temperature/heat flow sensing applications, their sensitivity is limited by their low Seebeck coefficient (∼100 μV K−1). Here we take advantage of the large ionic thermoelectric Seebeck coefficient found in polymer electrolytes (∼10,000 μV K−1) to introduce the concept of ionic thermoelectric gating a low-voltage organic transistor. The temperature sensing amplification of such ionic thermoelectric-gated devices is thousands of times superior to that of a single thermoelectric leg in traditional thermopiles. This suggests that ionic thermoelectric sensors offer a way to go beyond the limitations of traditional thermopiles and pyroelectric detectors. These findings pave the way for new infrared-gated electronic circuits with potential applications in photonics, thermography and electronic-skins. PMID:28139738

  10. Ionic thermoelectric gating organic transistors

    NASA Astrophysics Data System (ADS)

    Zhao, Dan; Fabiano, Simone; Berggren, Magnus; Crispin, Xavier

    2017-01-01

    Temperature is one of the most important environmental stimuli to record and amplify. While traditional thermoelectric materials are attractive for temperature/heat flow sensing applications, their sensitivity is limited by their low Seebeck coefficient (~100 μV K-1). Here we take advantage of the large ionic thermoelectric Seebeck coefficient found in polymer electrolytes (~10,000 μV K-1) to introduce the concept of ionic thermoelectric gating a low-voltage organic transistor. The temperature sensing amplification of such ionic thermoelectric-gated devices is thousands of times superior to that of a single thermoelectric leg in traditional thermopiles. This suggests that ionic thermoelectric sensors offer a way to go beyond the limitations of traditional thermopiles and pyroelectric detectors. These findings pave the way for new infrared-gated electronic circuits with potential applications in photonics, thermography and electronic-skins.

  11. Modeling electrokinetics in ionic liquids.

    PubMed

    Wang, Chao; Bao, Jie; Pan, Wenxiao; Sun, Xin

    2017-03-17

    Using direct numerical simulations, we provide a thorough study regarding the electrokinetics of ionic liquids. In particular, modified Poisson-Nernst-Planck (MPNP) equations are solved to capture the crowding and overscreening effects characteristic of an ionic liquid. For modeling electrokinetic flows in an ionic liquid, the MPNP equations are coupled with Navier-Stokes equations to study the coupling of ion transport, hydrodynamics, and electrostatic forces. Specifically, we consider the ion transport between two parallel charged surfaces, charging dynamics in a nanopore, capacitance of electric double-layer capacitors, electro-osmotic flow in a nanochannel, electroconvective instability on a plane ion-selective surface, and electroconvective flow on a curved ion-selective surface. We also discuss how crowding and overscreening and their interplay affect the electrokinetic behaviors of ionic liquids in these application problems. This article is protected by copyright. All rights reserved.

  12. Novel approaches to ionic chromatography

    SciTech Connect

    Dasgupta, P.K.

    1990-11-01

    Research during this reporting period, continued on ionic chromatography. Major progress has been made towards on-line on-demand generation of ultrapure chemicals by electrochemical means. The concentration of the generated material is governed electrochemically.

  13. Chiral separation of phenylalanine and tryptophan by capillary electrophoresis using a mixture of β-CD and chiral ionic liquid ([TBA] [L-ASP]) as selectors.

    PubMed

    Yujiao, Wu; Guoyan, Wang; Wenyan, Zhao; Hongfen, Zhang; Huanwang, Jing; Anjia, Chen

    2014-05-01

    In this paper, a simple, effective and green capillary electrophoresis separation and detection method was developed for the quantification of underivatized amino acids (dl-phenylalanine; dl-tryptophan) using β-Cyclodextrin and chiral ionic liquid ([TBA] [l-ASP]) as selectors. Separation parameters such as buffer concentrations, pH, β-CD and chiral ionic liquid concentrations and separation voltage were investigated for the enantioseparation in order to achieve the maximum possible resolution. A good separation was achieved in a background electrolyte composed of 15 mm sodium tetraborate, 5 mm β-CD and 4 mm chiral ionic liquid at pH 9.5, and an applied voltage of 10 kV. Under optimum conditions, linearity was achieved within concentration ranges from 0.08 to 10 µg/mL for the analytes with correlation coefficients from 0.9956 to 0.9998, and the analytes were separated in less than 6 min with efficiencies up to 970,000 plates/m. The proposed method was successfully applied to the determination of amino acid enantiomers in compound amino acids injections, such as 18AA-I, 18AA-II and 3AA.

  14. Biopolymer Processing Using Ionic Liquids

    DTIC Science & Technology

    2014-08-07

    AFRL-OSR-VA-TR-2014-0181 (YIP-11) BIOPOLYMER PROCESSING USING IONIC LIQUIDS William Reichert UNIVERSITY OF SOUTH ALABAMA 08/07/2014 Final Report...3. DATES COVERED (From - To) May 2011-May 2014 4. TITLE AND SUBTITLE iopolymer Processing using Ionic Liquids for Feedstock Chemicals 5a...reaction and degradation products of the conversion of chitin and chitosan, and 3) investigate the effects of various reaction conditions, such as

  15. Ionic Liquid Epoxy Resin Monomers

    NASA Technical Reports Server (NTRS)

    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.

  16. Antifungal activity of ionic liquids based on (-)-menthol: a mechanism study.

    PubMed

    Suchodolski, Jakub; Feder-Kubis, Joanna; Krasowska, Anna

    2017-04-01

    The mechanism of toxicity of chiral ionic liquids with (1R,2S,5R)-(-)-menthol [Cn-Am-Men][Cl] (n=10, 11 or 12) in the fungus Candida albicans is reported here. Ionic liquids were more toxic towards Candida strain lacking all identified multidrug resistance efflux pumps. Moreover, the compounds tested inhibited C. albicans filamentation at the concentration at which detached fungal cells also adhered to the plastic surface. Our results showed the high activity of all the tested chiral ionic liquids in the permeabilization of C. albicans' membranes and in the digestion and interruption of the cell wall. The investigated ionic liquids thus have potential as disinfectants because besides their antifungal and antiadhesive action these compounds do not cause hemolysis.

  17. Design and Evaluation of Ionic Liquids as Novel CO2 Absorbents

    SciTech Connect

    Edward Maginn

    2007-07-15

    This is the final report for project DE-FG26-04NT42122 'Design and Evaluation of Ionic Liquids as Novel CO{sub 2} Absorbents'. The objective of this 'breakthrough concepts' project was to investigate the feasibility of using ionic liquids for post-combustion CO{sub 2} capture and obtain a fundamental understanding of the solubility of CO{sub 2} and other components present in flue gas in ionic liquids. Our plan was to obtain information on how composition and structure of ionic liquid molecules affected solubility and other important physical properties via two major efforts: synthesis and experimental measurements and molecular simulation. We also planned to perform preliminary systems modeling study to assess the economic viability of a process based on ionic liquids. We accomplished all the milestones and tasks specified in the original proposal. Specifically, we carried out extensive quantum and classical atomistic-level simulations of a range of ionic liquids. These calculations provided detailed information on how the chemical composition of ionic liquids affects physical properties. We also learned important factors that govern CO{sub 2} solubility. Using this information, we synthesized or acquired 33 new ionic liquids. Many of these had never been made before. We carried out preliminary tests on all of these compounds, and more extensive tests on those that looked most promising for CO{sub 2} capture. We measured CO{sub 2} solubility in ten of these ionic liquids. Through our efforts, we developed an ionic liquid that has a CO{sub 2} solubility 2.6 times greater than the 'best' ionic liquid available to us at the start of the project. Moreover, we demonstrated that SO{sub 2} is also extremely soluble in ionic liquids, opening up the possibility of using ionic liquids to remove both SO{sub 2} and CO{sub 2} from flue gas. In collaboration with Trimeric Inc., a preliminary systems analysis was conducted and the results used to help identify physical

  18. Sonofragmentation of Ionic Crystals.

    PubMed

    Kim, Hyo Na; Suslick, Kenneth S

    2017-02-24

    Mechanochemistry deals with the interface between the chemical and the mechanical worlds and explores the physical and chemical changes in materials caused by an input of mechanical energy. As such, the chemical and physical effects of ultrasound, i.e., sonochemistry, are forms of mechanochemistry. In this paper, the fragmentation of ionic crystals during ultrasonic irradiation of slurries has been quantitatively investigated: the rate of fragmentation depends strongly on the strength of the materials (as measured by Vickers hardness or by Young's modulus). This is a mechanochemical extension of the Bell-Evans-Polanyi Principle or Hammond's Postulate: activation energies for solid fracture correlate with binding energies of solids. Sonofragmentation is unaffected by slurry loading or liquid vapor pressure, but is suppressed by increasing liquid viscosity. The mechanism of the particle breakage is consistent with a direct interaction between the shockwaves created by the ultrasound (through acoustic cavitation) and the solid particles in the slurry. Fragmentation is proposed to occur from defects in the solids induced by compression-expansion, bending, or torsional distortions of the crystals.

  19. Ion-polyether coordination complexes: crystalline ionic conductors for clean energy storage.

    PubMed

    Bruce, Peter G

    2006-03-21

    Ion-polyether complexes are the solid state analogues of crown ether and cryptand complexes. They represent a fascinating class of coordination compounds in their own right, with the ability to support ionic conductivity and the potential to be used as electrolytes in all-solid-state rechargeable lithium batteries. Here the recent discovery of ionic conductivity in crystalline ion-polyether complexes, when for 30 years such materials were considered to be insulators, is described, along with their closely related structural chemistry.

  20. Oxygen Extraction from Regolith Using Ionic Liquids

    NASA Technical Reports Server (NTRS)

    Barrios, Elizabeth A.; Curreri, Peter A.; Karr, Laurel J.

    2011-01-01

    An important concern with long-duration manned space travel is the need to furnish enough materials to the vehicle, as well as the crew, for the duration of the mission. By extracting oxygen from the oxides present in regolith, propellant and life support could be supplied to the vehicle and the crew while in space, thereby limiting the amount of supplies needed prior to lift-off. Using a class of compounds known as ionic liquids, we have been able to lower the electrolysis operating temperature from 1600 C (molten oxide electrolysis) to less than 200 C, making this process much more feasible in terms of energy consumption and materials handling. To make this process ready for deployment into space, we have investigated what steps of the process would be affected by the low-gravity environment in space. In the lab, the solubilization of lunar regolith simulant in ionic liquid produces water vapor that is normally distilled out of solution and subsequently electrolyzed for oxygen production. This distillation is not possible in space, so we have tested a method known as pervaporation and have suggested a way this technique could be incorporated into a reactor design.

  1. Mathematical modeling of ionic interactions and deformation in ionic polymer-metal composite artificial muscles

    NASA Astrophysics Data System (ADS)

    Firoozbakhsh, K.; Shahinpoor, Mohsen; Shavandi, M.

    1998-07-01

    This paper presents a simple mathematical model for surface deformation due to ionic interaction in connection with ion- exchange polymer-noble metal composites (IPMC) as biomimetic sensors and actuators. These smart composites exhibit characteristics of both actuators and sensors. Strips of these composites can undergo large bending and flapping displacement if an electric field is imposed across their thickness. Thus, in this sense they are large motion actuators. Conversely by bending the composite strip, either quasi-statically or dynamically, a voltage is produced across the thickness of the strip between the two conducting electrodes attached. Thus they are also large motion sensors. In this paper a simple mathematical model is presented for the role of ionic interactions, and in particular the sulfonic group actions and the metallic electrode anions, in surface deformation observed under an electric field in ionic polymeric-metal composite artificial muscles. It is shown that the columbic attraction/repulsion force distribution has its maximum at the edges of the surface and sharply decreases towards the center of the surface. Furthermore, the maximum force is not macroscopically scale dependent. This means that is attains its maximum over a short finite length. This fact can be used to design large force arrays with collective action for a number of industrial and medical applications. According to our findings an optimal muscle in force/motion capability should consist of series of miniaturized IPMC muscle strips similar to the structure of actual biological muscles' myofibrils consisting of sarcomeres. This paper further identifies key parameters involving the contraction/expansion force characteristics of sensors and actuators made of IPMC's.

  2. Automated cytochrome c oxidase bioassay developed for ionic liquids' toxicity assessment.

    PubMed

    Costa, Susana P F; Martins, Bárbara S F; Pinto, Paula C A G; Saraiva, M Lúcia M F S

    2016-05-15

    A fully automated cytochrome c oxidase assay resorting to sequential injection analysis (SIA) was developed for the first time and implemented to evaluate potential toxic compounds. The bioassay was validated by evaluation of 15 ionic liquids (ILs) with distinct cationic head groups, alkyl side chains and anions. The assay was based on cytochrome c oxidase activity reduction in presence of tested compounds and quantification of inhibitor concentration required to cause 50% of enzyme activity inhibition (EC50). The obtained results demonstrated that enzyme activity was considerably inhibited by BF4 anion and ILs incorporating non-aromatic pyrrolidinium and tetrabutylphosphonium cation cores. Emim [Ac] and chol [Ac], on contrary, presented the higher EC50 values among the ILs tested. The developed automated SIA methodology is a simple and robust high-throughput screening bioassay and exhibited good repeatability in all the tested conditions (rsd<3.7%, n=10). Therefore, it is expected that due to its simplicity and low cost, the developed approach can be used as alternative to traditional screening assays for evaluation of ILs toxicity and identification of possible toxicophore structures. Additionally, the results presented in this study provide further information about ILs toxicity.

  3. TOPICAL REVIEW: Molecular simulation of ionic liquids: current status and future opportunities

    NASA Astrophysics Data System (ADS)

    Maginn, E. J.

    2009-09-01

    Ionic liquids are salts that are liquid near ambient conditions. Interest in these unusual compounds has exploded in the last decade, both at the academic and commercial level. Molecular simulations based on classical potentials have played an important role in helping researchers understand how condensed phase properties of these materials are linked to chemical structure and composition. Simulations have also predicted many properties and unexpected phenomena that have subsequently been confirmed experimentally. The beneficial impact molecular simulations have had on this field is due in large part to excellent timing. Just when computing power and simulation methods matured to the point where complex fluids could be studied in great detail, a new class of materials virtually unknown to experimentalists came on the scene and demanded attention. This topical review explores some of the history of ionic liquid molecular simulations, and then gives examples of the recent use of molecular dynamics and Monte Carlo simulation in understanding the structure of ionic liquids, the sorption of small molecules in ionic liquids, the nature of ionic liquids in the vapor phase and the dynamics of ionic liquids. This review concludes with a discussion of some of the outstanding problems facing the ionic liquid modeling community and how condensed phase molecular simulation experts not presently working on ionic liquids might help advance the field.

  4. Biological Activity of Ionic Liquids and Their Application in Pharmaceutics and Medicine.

    PubMed

    Egorova, Ksenia S; Gordeev, Evgeniy G; Ananikov, Valentine P

    2017-01-26

    Ionic liquids are remarkable chemical compounds, which find applications in many areas of modern science. Because of their highly tunable nature and exceptional properties, ionic liquids have become essential players in the fields of synthesis and catalysis, extraction, electrochemistry, analytics, biotechnology, etc. Apart from physical and chemical features of ionic liquids, their high biological activity has been attracting significant attention from biochemists, ecologists, and medical scientists. This Review is dedicated to biological activities of ionic liquids, with a special emphasis on their potential employment in pharmaceutics and medicine. The accumulated data on the biological activity of ionic liquids, including their antimicrobial and cytotoxic properties, are discussed in view of possible applications in drug synthesis and drug delivery systems. Dedicated attention is given to a novel active pharmaceutical ingredient-ionic liquid (API-IL) concept, which suggests using traditional drugs in the form of ionic liquid species. The main aim of this Review is to attract a broad audience of chemical, biological, and medical scientists to study advantages of ionic liquid pharmaceutics. Overall, the discussed data highlight the importance of the research direction defined as "Ioliomics", studies of ions in liquids in modern chemistry, biology, and medicine.

  5. Surface-active ionic liquids in catalysis: Impact of structure and concentration on the aerobic oxidation of octanol in water.

    PubMed

    Cognigni, Alice; Kampichler, Sebastian; Bica, Katharina

    2017-04-15

    We present design and synthesis of surface-active ionic liquids for the application in micellar catalysis. A series of 1-methyl-3-dodecylimidazolium based ionic liquids with variable core structures including dicationic and zwitterionic ones was synthesized and characterized. These surface-active ionic liquids where applied in the aerobic oxidation of aliphatic alcohols to carbonyl compounds. A strong dependence on the ionic liquid concentration and structure was identified, which is in accordance with the concepts of micellar catalysis. Optimum conditions for the oxidation of 1-octanol could be identified, and the use of surface-active ionic liquids strongly improved the reaction performance compared to pure water. Under optimized conditions, it was possible to isolate up to 75% of octanoic acid using only small amounts of surface-active ionic liquid in a 0.05mM solution in water without further ligands.

  6. The Anticancer Potential of Ionic Liquids.

    PubMed

    Dias, Ana Rita; Costa-Rodrigues, João; Fernandes, Maria Helena; Ferraz, Ricardo; Prudêncio, Cristina

    2017-01-05

    Among the many challenges that the pharmaceutical industry currently faces is the need to develop innovative and effective therapies. The investigation of alternative and effective therapies against cancer is a current goal of the pharmaceutical industry. Ionic liquids (ILs) have emerged recently as a topic of study by researchers in the pharmaceutical industry in their search for new therapeutic agents. By definition, ILs are organic salts with melting points below 100 °C that are composed only by ions. Their main advantage lies in the numerous possible combinations of cations and anions, which allow adjustments in their physicochemical properties. The combination between ILs and active pharmaceutical ingredients (APIs) may improve the properties of APIs. In addition, the antitumor properties of these compounds have been described. Several studies have reported the use of ILs in biomedical applications as therapeutic agents, namely as antitumor agents. This review describes the recent proposed applications of ILs as antitumor agents.

  7. Multilayer ionic polymer transducer

    NASA Astrophysics Data System (ADS)

    Akle, Barbar J.; Leo, Donald J.

    2003-07-01

    A transducer consisting of multiple layers of ionic polymer material is developed for applications in sensing, actuation, and control. The transducer consists of two to four individual layers each approximately 200 microns thick. The transducers are connected in parallel to minimize the electric field requirements for actuation. The tradeoff in deflection and force can be controlled by controlling the mechanical constraint at the interface. Packaging the transducer in an outer coating produces a hard constraint between layers and reduces the deflection with a force that increases linearly with the number of layers. This configuration also increases the bandwidth of the transducer. Removing the outer packaging produces an actuator that maintains the deflection of a single layer but has an increased force output. This is obtained by allowing the layers to slide relative to one another during bending. Experiments on transducers with one to three layers are performed and the results are compared to Newbury"s equivalent circuit model, which was modified to accommodate the multilayer polymers. The modification was performed on four different boundary conditions, two electrical the series and the parallel connection, and two mechanical the zero interfacial friction and the zero slip on the interface. Results demonstrate that the largest obstacle to obtaining good performance is water transport between the individual layers. Water crossover produces a near short circuit electrical condition and produces feedthrough between actuation layers and sensing layers. Electrical feedthrough due to water crossover eliminates the ability to produce a transducer that has combined sensing and actuation properties. Eliminating water crossover through good insulation enables the development of a small (5 mm x 30 mm) transducer that has sensing and actuation bandwidth on the order of 100 Hz.

  8. Dual Ionic and Organic Nature of Ionic Liquids

    PubMed Central

    Shi, Rui; Wang, Yanting

    2016-01-01

    Inherited the advantages of inorganic salts and organic solvents, ionic liquids (ILs) exhibit many superior properties allowing them promising green solvents for the future. Although it has been widely acknowledged that the unique features of ILs originate from their dual ionic and organic nature, its microscopic physical origin still remains blurry. In this work, by comparing the ion/molecule cage structures obtained from molecular dynamics simulations for seven prototypic liquids—a molten inorganic salt, four ILs, a strongly polar organic solvent, and a weakly polar organic solvent, we have revealed that the depth of the cage energy landscape characterizes the ionic nature of ILs, whereas the slope and curvature of its mimimum determine the organic nature of ILs. This finding advances our understanding of ILs and thus will help their efficient utilization as well as the systematic design of novel functionalized ILs. PMID:26782660

  9. The Coulombic Lattice Potential of Ionic Compounds: The Cubic Perovskites.

    ERIC Educational Resources Information Center

    Francisco, E.; And Others

    1988-01-01

    Presents coulombic models representing the particles of a system by point charges interacting through Coulomb's law to explain coulombic lattice potential. Uses rubidium manganese trifluoride as an example of cubic perovskite structure. Discusses the effects on cluster properties. (CW)

  10. Determination of phenylurea and triazine herbicides in milk by microwave assisted ionic liquid microextraction high-performance liquid chromatography.

    PubMed

    Gao, Shiqian; You, Jingyan; Zheng, Xia; Wang, Ying; Ren, Ruibing; Zhang, Rui; Bai, Yuping; Zhang, Hanqi

    2010-09-15

    The determination of phenylurea and triazine herbicides in milk based on microwave assisted ionic liquid microextraction (MAILME) coupled with high-performance liquid chromatographic separation was described. The experimental parameters of the MAILE, including type and amount of ionic liquid, microwave extraction power, extraction time and salt concentration in sample, were evaluated by a univariate method and orthogonal screening. When 60 microL of [C(6)MIM][PF(6)] was used as extraction solvent the target compounds can be isolated from the 4 mL of milk. The MAILME is quick (7 min) and simple. The detection limits for isoproturon, monolinuron, linuron, propazine, prometryne, terbutryn and trietazine are 0.46, 0.78, 1.00, 1.21, 1.96, 0.84 and 1.28 microg L(-1), respectively. The proposed method was applied to the analysis of milk samples and the recoveries of the analytes ranged from 88.4 to 117.9% and relative standard deviations were lower than 7.43%.

  11. Recrystallized quinolinium ionic liquids for electrochemical analysis

    NASA Astrophysics Data System (ADS)

    Selvaraj, Gowri; Wilfred, Cecilia Devi; Eang, Neo Kian

    2016-11-01

    Ionic liquids have received a lot of attention due to their unique properties. In this work the prospect of quinolinium based ionic liquids as electrolyte for dye sensitised solar cell were tested using cyclic voltammetry. The results have shown electron transfer in the ionic liquid without undergoing any permanent chemical changes. Prior to testing, the ionic liquids were purified through recrystallization as electrochemical properties of ionic liquids are highly dependent on the purity of the ionic liquids. This results have shone new light for this work.

  12. The dynamic behavior of thin-film ionic transition metal complex-based light-emitting electrochemical cells

    SciTech Connect

    Meier, Sebastian B. E-mail: wiebke.sarfert@siemens.com; Hartmann, David; Sarfert, Wiebke E-mail: wiebke.sarfert@siemens.com; Winnacker, Albrecht

    2014-09-14

    Light-emitting electrochemical cells (LECs) have received increasing attention during recent years due to their simple architecture, based on solely air-stabile materials, and ease of manufacture in ambient atmosphere, using solution-based technologies. The LEC's active layer offers semiconducting, luminescent as well as ionic functionality resulting in device physical processes fundamentally different as compared with organic light-emitting diodes. During operation, electrical double layers (EDLs) form at the electrode interfaces as a consequence of ion accumulation and electrochemical doping sets in leading to the in situ development of a light-emitting p-i-n junction. In this paper, we comment on the use of impedance spectroscopy in combination with complex nonlinear squares fitting to derive key information about the latter events in thin-film ionic transition metal complex-based light-emitting electrochemical cells based on the model compound bis-2-phenylpyridine 6-phenyl-2,2´-bipyridine iridium(III) hexafluoridophosphate ([Ir(ppy)₂(pbpy)][PF₆]). At operating voltages below the bandgap potential of the ionic complex used, we obtain the dielectric constant of the active layer, the conductivity of mobile ions, the transference numbers of electrons and ions, and the thickness of the EDLs, whereas the transient thickness of the p-i-n junction is determined at voltages above the bandgap potential. Most importantly, we find that charge transport is dominated by the ions when carrier injection from the electrodes is prohibited, that ion movement is limited by the presence of transverse internal interfaces and that the width of the intrinsic region constitutes almost 60% of the total active layer thickness in steady state at a low operating voltage.

  13. Preparation of stir cake sorptive extraction based on polymeric ionic liquid for the enrichment of benzimidazole anthelmintics in water, honey and milk samples.

    PubMed

    Wang, Yulei; Zhang, Jie; Huang, Xiaojia; Yuan, Dongxing

    2014-08-20

    In this work, a new stir cake sorptive extraction (SCSE) using polymeric ionic liquid monolith as sorbent was prepared. The sorbent was obtained by in situ copolymerization of an ionic liquid, 1-allyl-3-methylimidazolium bis[(trifluoro methyl)sulfonyl]imide (AMII) and divinylbenzene (DB) in the presence of N,N-dimethylformamide. The influence of the content of ionic liquid and the porogen in the polymerization mixture on extraction performance was studied thoroughly. The physicochemical properties of the polymeric ionic liquid were characterized by infrared spectroscopy, elemental analysis, scanning electron microscopy and mercury intrusion porosimetry. The usefulness of SCSE-AMIIDB was demonstrated by the enrichment of trace benzimidazole anthelmintics. Several parameters affecting the extraction efficiency were investigated, and under the optimized conditions, a simple and effective method for the determination of trace benzimidazoles residues in water, milk and honey samples was established by coupling SCSE-AMIIDB with high performance liquid chromatography/diode array detection (SCSE-AMIIDB-HPLC/DAD). Results indicated that the limits of detection (S/N=3) for target compounds were 0.020-0.072 μg L(-1), 0.035-0.10 μg L(-1) and 0.026-0.076 μg L(-1) in water, milk and honey samples, respectively. In addition, an acceptable reproducibility was achieved by evaluating the repeatability and intermediate precision with relative standard deviations (RSD) of less than 9% and 11%, respectively. Finally, the established AMII-SCSE-HPLC/DAD method was successfully applied for the determination of benzimidazoles residues in milk, honey and environmental water samples. Recoveries obtained for the determination of benzimidazole anthelmintics in spiking samples ranged from 70.2% to 117.6%, with RSD below 12% in all cases.

  14. Lithium ion conducting ionic electrolytes

    DOEpatents

    Angell, C.A.; Xu, K.; Liu, C.

    1996-01-16

    A liquid, predominantly lithium-conducting, ionic electrolyte is described which has exceptionally high conductivity at temperatures of 100 C or lower, including room temperature. It comprises molten lithium salts or salt mixtures in which a small amount of an anionic polymer lithium salt is dissolved to stabilize the liquid against recrystallization. Further, a liquid ionic electrolyte which has been rubberized by addition of an extra proportion of anionic polymer, and which has good chemical and electrochemical stability, is described. This presents an attractive alternative to conventional salt-in-polymer electrolytes which are not cationic conductors. 4 figs.

  15. Lithium ion conducting ionic electrolytes

    DOEpatents

    Angell, C. Austen; Xu, Kang; Liu, Changle

    1996-01-01

    A liquid, predominantly lithium-conducting, ionic electrolyte is described which has exceptionally high conductivity at temperatures of 100.degree. C. or lower, including room temperature. It comprises molten lithium salts or salt mixtures in which a small amount of an anionic polymer lithium salt is dissolved to stabilize the liquid against recrystallization. Further, a liquid ionic electrolyte which has been rubberized by addition of an extra proportion of anionic polymer, and which has good chemical and electrochemical stability, is described. This presents an attractive alternative to conventional salt-in-polymer electrolytes which are not cationic conductors.

  16. Corresponding-states behavior of an ionic model fluid with variable dispersion interactions

    NASA Astrophysics Data System (ADS)

    Weiss, Volker C.

    2016-06-01

    Guggenheim's corresponding-states approach for simple fluids leads to a remarkably universal representation of their thermophysical properties. For more complex fluids, such as polar or ionic ones, deviations from this type of behavior are to be expected, thereby supplying us with valuable information about the thermodynamic consequences of the interaction details in fluids. Here, the gradual transition of a simple fluid to an ionic one is studied by varying the relative strength of the dispersion interactions compared to the electrostatic interactions among the charged particles. In addition to the effects on the reduced surface tension that were reported earlier [F. Leroy and V. C. Weiss, J. Chem. Phys. 134, 094703 (2011)], we address the shape of the coexistence curve and focus on properties that are related to and derived from the vapor pressure. These quantities include the enthalpy and entropy of vaporization, the boiling point, and the critical compressibility factor Zc. For all of these properties, the crossover from simple to characteristically ionic fluid is seen once the dispersive attraction drops below 20%-40% of the electrostatic attraction (as measured for two particles at contact). Below this threshold, ionic fluids display characteristically low values of Zc as well as large Guggenheim and Guldberg ratios for the reduced enthalpy of vaporization and the reduced boiling point, respectively. The coexistence curves are wider and more skewed than those for simple fluids. The results for the ionic model fluid with variable dispersion interactions improve our understanding of the behavior of real ionic fluids, such as inorganic molten salts and room temperature ionic liquids, by gauging the importance of different types of interactions for thermodynamic properties.

  17. Surface tension of ionic liquids and ionic liquid solutions.

    PubMed

    Tariq, Mohammad; Freire, Mara G; Saramago, Benilde; Coutinho, João A P; Lopes, José N Canongia; Rebelo, Luís Paulo N

    2012-01-21

    Some of the most active scientific research fronts of the past decade are centered on ionic liquids. These fluids present characteristic surface behavior and distinctive trends of their surface tension versus temperature. One way to explore and understand their unique nature is to study their surface properties. This critical review analyses most of the surface tension data reported between 2001 and 2010 (187 references).

  18. Electrochemical properties of the double layer of an ionic liquid using a dimer model electrolyte and density functional theory.

    PubMed

    Henderson, Douglas; Wu, Jianzhong

    2012-03-01

    Most theoretical studies of the properties of an electrolyte, including an ionic liquid, treat the electrolyte as a mixture of charged hard spheres in a solvent modeled as a dielectric continuum. However, ionic liquids generally consist of nonspherical ions that are not dissolved in a solvent. A simple extension of the primitivel model of electrolytes is to represent an ionic liquid as a mixture of charged hard spheres (negative monovalent ions in our case) and nonspherical ions consisting of a dimer of two touching hard spheres, one of which is charged (monovalent and positive in our case) and the other is neutral. This simple model has been used previously by Federov et al. and by ourselves. Here, we use the classical density functional theory to study the interfacial properties of the model ionic liquid over a range of electrode charges and two electrolyte concentrations. For simplicity, all of the spheres have the same diameter. In contrast to the simulations of Federov and Kornyshev, we find that a plot of the differential capacitance of the dimer electrolyte versus the surface potential typically exhibits only a single hump. Also, differing from the studies of Lamperski et al. for a spherical electrolyte, which showed a decline of the maximal differential capacitance as the ionic concentration decreases, the maximum of the differential capacitance of the dimer electrolyte increases slightly with decreasing ionic concentration. Our theoretical results show other unexpected effects of the geometry of ionic species on the electrochemical properties of the electric double layer of an ionic liquid.

  19. "Practical" Electrospinning of Biopolymers in Ionic Liquids.

    PubMed

    Shamshina, Julia L; Zavgorodnya, Oleksandra; Bonner, Jonathan R; Gurau, Gabriela; Di Nardo, Thomas; Rogers, Robin D

    2017-01-10

    To address the need to scale up technologies for electrospinning of biopolymers from ionic liquids to practical volumes, a setup for the multi-needle electrospinning of chitin using the ionic liquid 1-ethyl-3-methylimidazolium acetate, [C2 mim]-[OAc], was designed, built, and demonstrated. Materials with controllable and high surface area were prepared at the nanoscale using ionic-liquid solutions of high-molecular-weight chitin extracted with the same ionic liquid directly from shrimp shells.

  20. Nanoparticle enhanced ionic liquid heat transfer fluids

    DOEpatents

    Fox, Elise B.; Visser, Ann E.; Bridges, Nicholas J.; Gray, Joshua R.; Garcia-Diaz, Brenda L.

    2014-08-12

    A heat transfer fluid created from nanoparticles that are dispersed into an ionic liquid is provided. Small volumes of nanoparticles are created from e.g., metals or metal oxides and/or alloys of such materials are dispersed into ionic liquids to create a heat transfer fluid. The nanoparticles can be dispersed directly into the ionic liquid during nanoparticle formation or the nanoparticles can be formed and then, in a subsequent step, dispersed into the ionic liquid using e.g., agitation.

  1. Corrosion prevention of magnesium surfaces via surface conversion treatments using ionic liquids

    DOEpatents

    Qu, Jun; Luo, Huimin

    2016-09-06

    A method for conversion coating a magnesium-containing surface, the method comprising contacting the magnesium-containing surface with an ionic liquid compound under conditions that result in decomposition of the ionic liquid compound to produce a conversion coated magnesium-containing surface having a substantially improved corrosion resistance relative to the magnesium-containing surface before said conversion coating. Also described are the resulting conversion-coated magnesium-containing surface, as well as mechanical components and devices containing the conversion-coated magnesium-containing surface.

  2. Parallel microwave-assisted synthesis of ionic liquids and screening for denitrogenation of straight-run diesel feed by liquid-liquid extraction.

    PubMed

    Ceron, Miguel A; Guzman-Lucero, Diego J; Palomeque, Jorge F; Martínez-Palou, Rafael

    2012-06-01

    Fifty-six ionic liquids were efficiently synthesized in parallel format under one-pot, solvent-free microwave-assisted synthesis. These compounds were evaluated as extracting agents of nitrogen-containing compounds from a real Diesel feed before being submitted to the hydrodesulfurization process to obtain ultralow sulfur Diesel. Our results showed that halogenated ionic liquids are an excellent alternative due to these ionic liquids are relatively inexpensive, presenting a high selectivity for the extraction of nitrogen-containing compounds and can be regenerated and recycled.

  3. High-flux ionic diodes, ionic transistors and ionic amplifiers based on external ion concentration polarization by an ion exchange membrane: a new scalable ionic circuit platform.

    PubMed

    Sun, Gongchen; Senapati, Satyajyoti; Chang, Hsueh-Chia

    2016-04-07

    A microfluidic ion exchange membrane hybrid chip is fabricated using polymer-based, lithography-free methods to achieve ionic diode, transistor and amplifier functionalities with the same four-terminal design. The high ionic flux (>100 μA) feature of the chip can enable a scalable integrated ionic circuit platform for micro-total-analytical systems.

  4. High-flux ionic diodes, ionic transistors and ionic amplifiers based on external ion concentration polarization by an ion exchange membrane: a new scalable ionic circuit platform†

    PubMed Central

    Sun, Gongchen; Senapati, Satyajyoti

    2016-01-01

    A microfluidic-ion exchange membrane hybrid chip is fabricated by polymer-based, lithography-free methods to achieve ionic diode, transistor and amplifier functionalities with the same four-terminal design. The high ionic flux (> 100 μA) feature of the chip can enable a scalable integrated ionic circuit platform for micro-total-analytical systems. PMID:26960551

  5. Study of toxicity of imidazolium ionic liquids to watercress (Lepidium sativum L.).

    PubMed

    Studzińska, Sylwia; Buszewski, Bogusław

    2009-02-01

    The sensitivity of Lepidium sativum L. germination to three imidazolium ionic liquids was investigated in solutions and soils artificially contaminated with mixtures of those compounds. In case of aquatic solutions, the toxic character of analyzed compounds is connected with their hydrophobicity. The seedling growth is increasing with the decrease in ionic liquid hydrophobicity. The novelty of those studies is the application of high-performance liquid chromatography, which was used for the determination of ionic liquid quantity absorbed by cress. There was almost linear relationship between decrease in root germination and amount of ionic liquid uptaken by cress. Furthermore, the systematic studies on the influence of total organic carbon content in soil on the toxicity of ionic liquids to cress were performed for the first time. Hazardous effects appeared to be closely connected with organic matter: with the decrease of total organic carbon quantity, the inhibition of plant growth was more significant. Visual effects of ionic liquid toxic activity to garden cress are similar as in the case of nutrient deficit in plants.

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

    PubMed

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

    2009-01-01

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

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

    SciTech Connect

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

    2014-04-15

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

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

    DOE PAGES

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

    2014-04-15

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

  9. Design of Energetic Ionic Liquids

    DTIC Science & Technology

    2010-04-15

    dynamics and structure in imidazolium -based ionic liquids/water mixtures. [15] The results of density and molar volume profile from MD simulations are...depending upon their respective attachment to boron or oxygen). The large blue sphere represents imidazolium ring. (b) The average sizes of cation

  10. Fluctuating hydrodynamics for ionic liquids

    NASA Astrophysics Data System (ADS)

    Lazaridis, Konstantinos; Wickham, Logan; Voulgarakis, Nikolaos

    2017-04-01

    We present a mean-field fluctuating hydrodynamics (FHD) method for studying the structural and transport properties of ionic liquids in bulk and near electrified surfaces. The free energy of the system consists of two competing terms: (1) a Landau-Lifshitz functional that models the spontaneous separation of the ionic groups, and (2) the standard mean-field electrostatic interaction between the ions in the liquid. The numerical approach used to solve the resulting FHD-Poisson equations is very efficient and models thermal fluctuations with remarkable accuracy. Such density fluctuations are sufficiently strong to excite the experimentally observed spontaneous formation of liquid nano-domains. Statistical analysis of our simulations provides quantitative information about the properties of ionic liquids, such as the mixing quality, stability, and the size of the nano-domains. Our model, thus, can be adequately parameterized by directly comparing our prediction with experimental measurements and all-atom simulations. Conclusively, this work can serve as a practical mathematical tool for testing various theories and designing more efficient mixtures of ionic liquids.

  11. Simple Kidney Cysts

    MedlinePlus

    ... How They Work Kidney Disease A-Z Simple Kidney Cysts What are simple kidney cysts? Simple kidney cysts are abnormal, fluid-filled ... that form in the kidneys. What are the kidneys and what do they do? The kidneys are ...

  12. Simple Elbow Dislocation.

    PubMed

    Armstrong, April

    2015-11-01

    Simple elbow dislocation refers to those elbow dislocations that do not involve an osseous injury. A complex elbow dislocation refers to an elbow that has dislocated with an osseous injury. Most simple elbow dislocations are treated nonoperatively. Understanding the importance of the soft tissue injury following a simple elbow dislocation is a key to being successful with treatment.

  13. SIMPLE: An Introduction.

    ERIC Educational Resources Information Center

    Endres, Frank L.

    Symbolic Interactive Matrix Processing Language (SIMPLE) is a conversational matrix-oriented source language suited to a batch or a time-sharing environment. The two modes of operation of SIMPLE are conversational mode and programing mode. This program uses a TAURUS time-sharing system and cathode ray terminals or teletypes. SIMPLE performs all…

  14. A rapid and simple assay for lamotrigine in serum/plasma by HPLC, and comparison with an immunoassay.

    PubMed

    Morgan, Phillip E; Fisher, Danielle S; Evers, Richard; Flanagan, Robert J

    2011-07-01

    Monitoring serum/plasma concentrations of lamotrigine may be useful under certain circumstances. An HPLC column packed with strong cation-exchange (SCX)-modified microparticulate silica together with a 100% methanol eluent containing an ionic modifier permits direct injection of sample extracts. An HPLC-UV method developed using this principle for the measurement of serum/plasma lamotrigine is simple, sensitive and selective. The analysis time is less than 5 min. Intra- and inter-assay precision and accuracy meet acceptance criteria, and sample stability, and potential interferences from other compounds have been evaluated. There was good agreement with consensus mean results from external quality assessment samples (n = 32). Analysis of patient samples (n = 115) using the HPLC method and the Seradyn QMS® Lamotrigine immunoassay showed that the immunoassay over-estimated lamotrigine by 21% on average.

  15. Accelerated materials design of fast oxygen ionic conductors based on first principles calculations

    NASA Astrophysics Data System (ADS)

    He, Xingfeng; Mo, Yifei

    Over the past decades, significant research efforts have been dedicated to seeking fast oxygen ion conductor materials, which have important technological applications in electrochemical devices such as solid oxide fuel cells, oxygen separation membranes, and sensors. Recently, Na0.5Bi0.5TiO3 (NBT) was reported as a new family of fast oxygen ionic conductor. We will present our first principles computation study aims to understand the O diffusion mechanisms in the NBT material and to design this material with enhanced oxygen ionic conductivity. Using the NBT materials as an example, we demonstrate the computation capability to evaluate the phase stability, chemical stability, and ionic diffusion of the ionic conductor materials. We reveal the effects of local atomistic configurations and dopants on oxygen diffusion and identify the intrinsic limiting factors in increasing the ionic conductivity of the NBT materials. Novel doping strategies were predicted and demonstrated by the first principles calculations. In particular, the K doped NBT compound achieved good phase stability and an order of magnitude increase in oxygen ionic conductivity of up to 0.1 S cm-1 at 900 K compared to the experimental Mg doped compositions. Our results provide new avenues for the future design of the NBT materials and demonstrate the accelerated design of new ionic conductor materials based on first principles techniques. This computation methodology and workflow can be applied to the materials design of any (e.g. Li +, Na +) fast ion-conducting materials.

  16. Shape memory rubber bands & supramolecular ionic copolymers

    NASA Astrophysics Data System (ADS)

    Brostowitz, Nicole

    The primary focus of this dissertation is to understand the thermo-mechanical properties that govern shape memory in rubber blends. An ideal shape memory polymer (SMP) has a large entropic component that drives shape recovery with a distinct transition mechanism to control the recovery conditions. Polyisoprene rubber is highly elastic and shows shape memory behavior through strain induced crystallization above its glass transition temperature. However, this transition temperature is below 0°C and not suitable for most applications. Shape memory blends can tailor the transition temperature through selection of the switching phase. Most SMP blends require complicated synthesis routes or intensive compounding which would be inhibitive for production. A facile method was developed for fabrication of a robust shape memory polymer by swelling cross-linked natural rubber with stearic acid. Thermal, microscopic studies showed that stearic acid formed a percolated network of crystalline platelets within the natural rubber. Further investigation of the material interactions was carried out with a low molecular weight polyisoprene analog, squalene, and stearic acid gel. Tensile tests on the rubber band demonstrated the thermo-mechanical effect of swelling with stearic acid. Low hysteresis was observed under cyclic loading which indicated viability for the stearic acid swollen rubber band as an SMP. The microscopic crystals and the cross-linked rubber produce a temporary network and a permanent network, respectively. These two networks allow thermal shape memory cycling with deformation and recovery above the melting point of stearic acidand fixation below that point. Under manual, strain-controlled tensile deformation, the shape memory rubber bands exhibited fixity and recovery of 100% +/- 10%. The recovery properties of the SMP were studied under various loading conditions and a model was fit to describe the potential recovery with relation to the fixation. An additional

  17. Correlating Humidity-Dependent Ionically Conductive Surface Area with Transport Phenomena in Proton-Exchange Membranes

    SciTech Connect

    He, Qinggang; Kusoglu, Ahmet; Lucas, Ivan T.; Clark, Kyle; Weber, Adam Z.; Kostecki, Robert

    2011-08-01

    The objective of this effort was to correlate the local surface ionic conductance of a Nafion? 212 proton-exchange membrane with its bulk and interfacial transport properties as a function of water content. Both macroscopic and microscopic proton conductivities were investigated at different relative humidity levels, using electrochemical impedance spectroscopy and current-sensing atomic force microscopy (CSAFM). We were able to identify small ion-conducting domains that grew with humidity at the surface of the membrane. Numerical analysis of the surface ionic conductance images recorded at various relative humidity levels helped determine the fractional area of ion-conducting active sites. A simple square-root relationship between the fractional conducting area and observed interfacial mass-transport resistance was established. Furthermore, the relationship between the bulk ionic conductivity and surface ionic conductance pattern of the Nafion? membrane was examined.

  18. Application of thermodynamic-based retention time prediction to ionic liquid stationary phases.

    PubMed

    Weber, Brandon M; Harynuk, James J

    2014-06-01

    First- and second-dimension retention times for a series of alkyl phosphates were predicted for multiple column combinations in GC×GC. This was accomplished through the use of a three-parameter thermodynamic model where the analytes' interactions with the stationary phases in both dimensions are known. Ionic liquid columns were employed to impart unique selectivity for alkyl phosphates, and it was determined that for alkyl phosphate compounds, ionic liquid columns are best used in the primary dimension. Retention coordinates for unknown phosphates are predicted from the thermodynamic parameters of a set standard alkyl phosphates. Additionally, we present changing retention properties of alkyl phosphates on some ionic liquid columns, due to suspected reaction between the analyte and column. This makes it difficult to accurately predict their retention properties, and in general poses a problem for ionic liquid columns with these types of analytes.

  19. Ionic liquids and deep eutectic solvents in natural products research: mixtures of solids as extraction solvents.

    PubMed

    Dai, Yuntao; van Spronsen, Jaap; Witkamp, Geert-Jan; Verpoorte, Robert; Choi, Young Hae

    2013-11-22

    Mixtures of solid chemicals may become liquid under certain conditions. These liquids are characterized by the formation of strong ionic (ionic liquids) or hydrogen bonds (deep eutectic solvents). Due to their extremely low vapor pressure, they are now widely used in polymer chemistry and synthetic organic chemistry, yet little attention has been paid to their use as extraction solvents of natural products. This review summarizes the preparation of ionic liquids and deep eutectic solvents with natural product components and recent progress in their applications to the extraction and analysis of natural products as well as the recovery of extracted compounds from their extracts. Additionally, various factors affecting extraction features of ionic liquids and deep eutectic solvents, as well as potential useful technologies including microwave and ultrasound to increase the extraction efficiency, are discussed.

  20. Ecotoxicity analysis of cholinium-based ionic liquids to Vibrio fischeri marine bacteria.

    PubMed

    Ventura, Sónia P M; e Silva, Francisca A; Gonçalves, Ana M M; Pereira, Joana L; Gonçalves, Fernando; Coutinho, João A P

    2014-04-01

    Cholinium-based ionic liquids are quaternary ammonium salts with a wide range of potential industrial applications. Based on the fact that the cholinium is a complex B vitamin and widely used as food additive, the cholinium-based ionic liquids are generically regarded as environmentally "harmless" and thus, accepted as "non-toxic", although their ecotoxicological profile is poorly known. This work provides new ecotoxicological data for ten cholinium-based salts and ionic liquids, aiming to extend the surprisingly restricted body of knowledge about the ecotoxicity of this particular family and to gain insight on the toxicity mechanism of these compounds. The results reported here show that not all the cholinium tested can be considered harmless towards the test organism adopted. Moreover, the results suggest that the cholinium family exhibits a different mechanism of toxicity as compared to the imidazolium ionic liquids previously described in the literature.

  1. Ionic liquid-induced synthesis of selenium nanoparticles

    SciTech Connect

    Langi, Bhushan; Shah, Chetan; Singh, Krishankant; Chaskar, Atul; Kumar, Manmohan; Bajaj, Parma N.

    2010-06-15

    A simple wet chemical method has been used to synthesize selenium nanoparticles by the reaction of ionic liquid with sodium selenosulphate, a selenium precursor, in the presence of polyvinyl alcohol stabilizer, in aqueous medium. The method is capable of producing spherical selenium nanoparticles in the size range of 76-150 nm under ambient conditions. This is a first report on the production of nano-selenium assisted by an ionic liquid. The synthesized nanoparticles can be separated easily from the aqueous sol by a high-speed centrifuge machine, and can be re-dispersed in an aqueous medium. The synthesized selenium nanoparticles have been characterized by X-ray diffraction, energy dispersive X-ray analysis, differential scanning calorimetry and transmission electron microscopy techniques.

  2. Modeling of solvent and ionic fluxes in electronanofiltration

    SciTech Connect

    Pupunat, L.; Rios, G.M.; Joulie, R.

    1999-07-01

    Electronanofiltration (ENF) is a new membrane separation process that uses an additional electric field between the permeate and retentate sides during nanofiltration. A recently published pioneering work gives the performance with single and mixed ionic solutions containing one monovalent cation and one or two anions (mono-or/and divalent). It appears that the electric field leads to a net increase of cation flux and a decrease of anion permeation at the same time if the cathode is placed on the permeate side. In relation with the well-known dependence of solvent flux on transmembrane pressure, these data open up potential applications of ENF for new integrated operations of ion separation/concentration. In this paper a semiempirical model accounting for permeate and ionic fluxes is proposed. Based on the Sefan-Maxwell approach, a simple set of linearized equations is developed that fits experimental data at various transmembrane pressure ({Delta}P), electric fields ({Delta}U), and concentrations (C).

  3. Ionic channels in biological membranes- electrostatic analysis of a natural nanotube

    NASA Astrophysics Data System (ADS)

    Eisenberg, Bob

    1998-06-01

    Ionic channels are proteins with holes down their middle that control access to biological cells and thus govern an enormous range of biological functions important in health and disease. A substantial fraction of the drugs used in clinical medicine act directly or indirectly on channels. Channels have a simple well-defined structure, and the fundamental mechanism of ionic motion is known to be electrodiffusion. The current through individual channel molecules can easily be measured, and is in fact measured in hundreds if not thousands of laboratories everyday. Thus, ionic channels are ideal objects for physical investigation: on the one hand, they are well-defined structures following simple physics, on the other hand they are of general biological importance. A simple theory of ion permeation through a channel is presented, in which diffusion occurs according to Fick's law and drift according to Ohm's law, in the electric field determined by all the charges present. This theory accounts for permeation in the channels studied to date in a wide range of solutions. Interestingly, the theory works because the shape of the electric field is a sensitive function of experimental conditions, e.g. ion concentration. Rate constants for flux are sensitive functions of ionic concentration because the fixed charge of the channel protein is shielded by the ions in and near it. Such shielding effects are not included in traditional theories of ionic channels, or other proteins, for that matter.

  4. Mechanistic Study of Oxygen Atom Transfer Catalyzed by Rhenium Compounds

    SciTech Connect

    Shan, Xiaopeng

    2003-01-01

    Two ionic and one neutral methyl(oxo)rhenium(V) compounds were synthesized and structurally characterized. They were compared in reactivity towards the ligands triphenylphosphane, pyridines, pyridine N-oxides. Assistance from Broensted bases was found on ligand displacement of ionic rhenium compounds as well as nucleophile assistance on oxidation of all compounds. From the kinetic data, crystal structures, and an analysis of the intermediates, a structural formula of PicH+3- and mechanisms of ligand displacement and oxidation were proposed.

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

    PubMed Central

    2015-01-01

    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. PMID:26562739

  6. Correlation of three-liquid-phase equilibria involving ionic liquids.

    PubMed

    Rodríguez-Escontrela, I; Arce, A; Soto, A; Marcilla, A; Olaya, M M; Reyes-Labarta, J A

    2016-08-03

    The difficulty in achieving a good thermodynamic description of phase equilibria is finding a model that can be extended to a large variety of chemical families and conditions. This problem worsens in the case of systems containing more than two phases or involving complex compounds such as ionic liquids. However, there are interesting applications that involve multiphasic systems, and the promising features of ionic liquids suggest that they will play an important role in many future processes. In this work, for the first time, the simultaneous correlation of liquid-liquid and liquid-liquid-liquid equilibrium data for ternary systems involving ionic liquids has been carried out. To that end, the phase diagram of the water + [P6 6 6 14][DCA] + hexane system has been determined at 298.15 K and 323.15 K and atmospheric pressure. The importance of this system lies in the possibility of using the surface active ionic liquid to improve surfactant enhanced oil recovery methods. With those and previous measurements, thirteen sets of equilibrium data for water + ionic liquid + oil ternary systems have been correlated. The isoactivity equilibrium condition, using the NRTL model, and some pivotal strategies are proposed to correlate these complex systems. Good agreement has been found between experimental and calculated data in all the regions (one triphasic and two biphasic) of the diagrams. The geometric aspects related to the Gibbs energy of mixing function obtained using the model, together with the minor common tangent plane equilibrium condition, are valuable tools to check the consistency of the obtained correlation results.

  7. Observation of ionic Coulomb blockade in nanopores

    NASA Astrophysics Data System (ADS)

    Feng, Jiandong; Liu, Ke; Graf, Michael; Dumcenco, Dumitru; Kis, Andras; di Ventra, Massimiliano; Radenovic, Aleksandra

    2016-08-01

    Emergent behaviour from electron-transport properties is routinely observed in systems with dimensions approaching the nanoscale. However, analogous mesoscopic behaviour resulting from ionic transport has so far not been observed, most probably because of bottlenecks in the controlled fabrication of subnanometre nanopores for use in nanofluidics. Here, we report measurements of ionic transport through a single subnanometre pore junction, and the observation of ionic Coulomb blockade: the ionic counterpart of the electronic Coulomb blockade observed for quantum dots. Our findings demonstrate that nanoscopic, atomically thin pores allow for the exploration of phenomena in ionic transport, and suggest that nanopores may also further our understanding of transport through biological ion channels.

  8. Ionic resistance measurements of battery separators

    SciTech Connect

    Danko, T.; Sybeldon, A.

    1997-12-01

    The performance of a battery is affected by the ionic resistance of the separator used to separate the anode from the cathode. If the ionic resistance is too high, the power output from the battery is diminished because the flow of ions is hindered. This paper examines issues that affect the ionic resistance of regenerated cellulose membranes. In particular, changes in the pore size, or molecular weight cut off, of the membranes are correlated with ionic resistance to show that changes in molecular weight cut off do effect ionic resistance.

  9. Application of Ionic Liquids in Hydrometallurgy

    PubMed Central

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

    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 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. PMID:25177864

  10. Ionic diffusion in single crystals of vermiculite

    SciTech Connect

    Maraqah, H.R.

    1993-01-01

    Novel guest-host compounds, based on single crystal vermiculite, were synthesized by diffusive techniques through a new hydrogen vermiculite. Single crystals were chosen because of the ease of characterization. An investigation of the ion transport properties of these single crystals was done to determine the mechanism of conductivity including the predominant charge carrier. Measurements of the ionic conductivity using impedance spectroscopy and X-ray lattice parameters of the ion-exchanged samples strongly suggest that the native cations and not protons are the major current carriers. Single crystals of hydrogen vermiculite were synthesized at room temperature by ion exchange from sodium-vermiculite using 1 molar acetic acid for a one week. Subsequent ion exchange with other cations was found to be much enhanced. Thus transition metals were exchanged in about a week in contrast to the need of several months using previous methods. The ionic conductivity of hydrogen vermiculite was measured and shown to be much lower than that of many other monovalent cations in the same host lattice. Its enthalpy of motion is also much lower. These marked differences suggest that protonic species do not play a significant role in charge transport in these layered materials. These materials were characterized by x-ray powder diffraction, thermogravimetric analysis and acid-base titration. Hydrogen-vermiculite was found to react with organic bases, like methylamine, ethylamine, n-butylamine, n-hexylamine, n-octylamine, n-decylamine, aniline, acrylamide, methacrylaminde, urea, 1,10phenanthroline, and 1,1phenanthroline ferrous sulfate complex, to undergo ion exchange with metal cations like sodium, zinc, copper(II) ions and polymerization reactions could be performed in the galleries of the structure like pyrrole and aniline. Its behavior was compared with that of powdered montmorillonite.

  11. Augmentation of hemagglutination by low ionic conditions.

    PubMed

    Rosenfield, R E; Shaikh, S H; Innella, F; Kaczera, Z; Kochwa, S

    1979-01-01

    Short incubation at 37 C, 80 per cent reduction in ionic concentration and removal of liquid phases after each reaction step, provided the basis for the construction of four new serologic tests for alloantibodies to human erythrocytes. In the first, the incubation fluid was replaced with protamine sulfate to aggregate intensely the evaluated red blood cells. After dispersal by phosphate buffer, residual antibody mediated agglutination could be discerned. As a second method, this low ionic polycation (LIP) test was followed by a normal ionic IgG antiglobulin test (LIP-AGT). A third method employed low ionic washing of erythrocytes and low ionic antiglobulin serum (LIAGT). Finally, a modified LIP test was conducted entirely under low ionic conditions and followed by a low ionic antiglobulin test (modified LIP-AGT). LIP, LIP-AGT and LIAGT were successfully employed for all routine blood bank serology tests. Their sensitivity and impact on blood bank performance are described.

  12. TRIFLUOROMETHYL COMPOUNDS OF GERMANIUM

    DTIC Science & Technology

    FLUORIDES, *GERMANIUM COMPOUNDS, *HALIDES, *ORGANOMETALLIC COMPOUNDS, ALKYL RADICALS, ARSENIC COMPOUNDS, CHEMICAL BONDS, CHEMICAL REACTIONS ...CHLORIDES, CHLORINE COMPOUNDS, HYDROLYSIS, IODIDES, METHYL RADICALS, POTASSIUM COMPOUNDS, PYROLYSIS, STABILITY, SYNTHESIS, TIN COMPOUNDS.

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

    PubMed

    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.

  14. Photochemical hole burning of ionic porphins and the deuterated analogues

    NASA Astrophysics Data System (ADS)

    Sakoda, Kazuaki; Maeda, Masayuki

    1994-01-01

    The quantum yields of photochemical hole burning (PHB) of three ionic porphins and their deuterated analogues doped in poly(vinylalcohol) and poly(sodium 4-styrenesulfonate) were estimated. The deuterated compounds, whose two hydrogen atoms at the nitrogen sites in the porphin ring were exchanged with deuterium atoms, were synthesized by reacting the non-deuterated compounds with heavy water. The quantum yield of the deuterated porphin was 18 to 45 times smaller than that of the non-deuterated compound. Besides, the hole area did not decrease at least up to about 60 K. These two facts definitely show that the main mechanism of PHB in this system is not a photophysical process, but the tautomerization of the porphin ring.

  15. Evaluation of anti-corrosive lubricating behavior of dicationic ionic liquid coatings for biomedical alloys

    NASA Astrophysics Data System (ADS)

    Siddiqui, Danyal Alam

    Since their inception, orthopedic implants composed of biomedical alloys have been plagued with failures associated with corrosion and wear processes. Despite current surface treatments and techniques being employed to mitigate corrosion and wear, these failure mechanisms continue to occur as prevalent failure modes. Recently, a novel class of compounds known as ionic liquids has been proposed as a multi-functional coating to protect the surfaces of commercially pure titanium surfaces comprising dental implants. In this study, the goal was to evaluate select formulations of these ionic liquids to serve as anti-corrosive lubricants for titanium and cobalt chromium molybdenum alloys widely used in orthopedic implants. Electrochemical and tribological testing of dicationic imidazolium-based ionic liquids revealed these compounds to be superior candidates as corrosion inhibitors and lubricants of biomedical alloy surfaces.

  16. Ionic liquids as lubricants or lubrication additives: an ecotoxicity and biodegradability assessment.

    PubMed

    Stolte, Stefan; Steudte, Stephanie; Areitioaurtena, Olatz; Pagano, Francesco; Thöming, Jorg; Stepnowski, Piotr; Igartua, Amaya

    2012-11-01

    This paper reports on the (eco)toxicity and biodegradability of ionic liquids considered for application as lubricants or lubrication additives. Ammonium- and pyrrolidinium-based cations combined with methylsulphate, methylsulphonate and/or (CF(3)SO(2))(2)N(-) anions were investigated in tests to determine their aquatic toxicity using water fleas Daphnia magna, green algae Selenastrum capricornutum and marine bacteria (Vibrio fischeri). Additional test systems with an isolated enzyme (acetylcholinesterase) and isolated leukaemia cells from rats (IPC-81) were used to assess the biological activity of the ionic liquids. These compounds generally exhibit low acute toxicity and biological activity. Their biodegradability was screened according to OECD test procedures 301 B and 301 F. For choline and methoxy-choline ionic liquids ready biodegradability was observed within 5 or 10 d, respectively. Some of the compounds selected have a considerable potential to contribute to the development of more sustainable products and processes.

  17. Membrane rejection of nitrogen compounds

    NASA Technical Reports Server (NTRS)

    Lee, S.; Lueptow, R. M.

    2001-01-01

    Rejection characteristics of nitrogen compounds were examined for reverse osmosis, nanofiltration, and low-pressure reverse osmosis membranes. The rejection of nitrogen compounds is explained by integrating experimental results with calculations using the extended Nernst-Planck model coupled with a steric hindrance model. The molecular weight and chemical structure of nitrogen compounds appear to be less important in determining rejection than electrostatic properties. The rejection is greatest when the Donnan potential exceeds 0.05 V or when the ratio of the solute radius to the pore radius is greater than 0.8. The transport of solute in the pore is dominated by diffusion, although convective transport is significant for organic nitrogen compounds. Electromigration contributes negligibly to the overall solute transport in the membrane. Urea, a small organic compound, has lower rejection than ionic compounds such as ammonium, nitrate, and nitrite, indicating the critical role of electrostatic interaction in rejection. This suggests that better treatment efficiency for organic nitrogen compounds can be obtained after ammonification of urea.

  18. Quantized ionic conductance in nanopores

    SciTech Connect

    Zwolak, Michael; Lagerqvist, Johan; Di Ventra, Massimilliano

    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.

  19. Ionic contamination detection. Final report

    SciTech Connect

    Benkovich, M.G.

    1994-04-01

    The effectiveness of Meter A and B for detecting ionic contamination was evaluated and compared on the following types of samples: (1) copper panels, (2) printed wiring boards with through-hold components (lCs), (3) printed wiring boards with surface-mounted components, and (4) mixed-technology printed wiring boards (both through-hole and surface-mount components). The extraction efficiency of the two meters was calculated

  20. Ionic Liquids for Advanced Materials

    DTIC Science & Technology

    2008-12-01

    developed characterization set-ups for the electromechanical responses of conductive network/ ionomer composite (CNIC). The overall research goal... glass transition temperature (Tg) with an increase in dielectric constant and ion content. ILs uniquely combine high dielectric constant, low...from 230-440%. Dissociation of ionic aggregates was observed at 85-88 °C in DMA experiments, and the glass transition temperatures increased with

  1. Phase Behavior of Ionic Microgels

    NASA Astrophysics Data System (ADS)

    Gottwald, D.; Likos, C. N.; Kahl, G.; Löwen, H.

    2004-02-01

    We employ effective interaction potentials between spherical polyelectrolyte microgels in order to investigate theoretically the structure, thermodynamics, and phase behavior of ionic microgel solutions. Combining a genetic algorithm with accurate free energy calculations we are able to perform an unrestricted search of candidate crystal structures. Hexagonal, body-centered orthogonal, and trigonal crystals are found to be stable at high concentrations and charges of the microgels, accompanied by reentrant melting behavior and fluid-fcc-bcc transitions below the overlap concentration.

  2. Phase behavior of ionic microgels.

    PubMed

    Gottwald, D; Likos, C N; Kahl, G; Löwen, H

    2004-02-13

    We employ effective interaction potentials between spherical polyelectrolyte microgels in order to investigate theoretically the structure, thermodynamics, and phase behavior of ionic microgel solutions. Combining a genetic algorithm with accurate free energy calculations we are able to perform an unrestricted search of candidate crystal structures. Hexagonal, body-centered orthogonal, and trigonal crystals are found to be stable at high concentrations and charges of the microgels, accompanied by reentrant melting behavior and fluid-fcc-bcc transitions below the overlap concentration.

  3. Ionic Conduction in Nanocrystalline Materials

    DTIC Science & Technology

    2000-02-10

    photo- largely due to oxygen desorption from particle voltaic cells and as the photocatalyst in water surfaces. The latter interpretation...and Tuller [22] prepared dense (-95%) temperature, where bulk reduction was observed. At compacts of TiO2 with the anatase phase. The lower... TiO2 , evidence preparation. is mixed. Nanocrystalline rutile appears to exhibit higher ionic conductivity than single crystal rutile while

  4. Fabrication of a Multi-Walled Nanotube (MWNT) Ionic Liquid Electrode and Its Application for Sensing Phenolics in Red Wines

    PubMed Central

    Kim, Kyo-Il; Kang, Hee-Young; Lee, Jae-Chan; Choi, Seong-Ho

    2009-01-01

    A multi-walled nanotube (MWNT) ionic liquid was prepared by the immobilization of 1-butylimidazole bromide onto an epoxy group on a poly(glycidyl methacrylate)-grafted MWNT, which was synthesized by radiation-induced graft polymerization of glycidyl methacrylate onto MWNT in an aqueous solution. Subsequently, a MWNT ionic liquid electrode was fabricated by hand-casting MWNT ionic liquid, tyrosinase, and chitosan solution as a binder on indium tin oxide (ITO) glass. The sensing ranges of the MWNT ionic liquid electrode with immobilized tyrosinase was in the range of 0.01-0.08 mM in a phosphate buffer solution. The optimal conditions such as pH, temperature, and effects of different phenolic compounds were determined. The total phenolic compounds of three commercial red wines were also determined on the tyrosinase-immobilized biosensor. PMID:22399973

  5. DIRECT FORMATION OF TETRAHYDROPYRANOLS VIA CATALYSIS IN IONIC LIQUID. (R828129)

    EPA Science Inventory

    Utilizing a simple homoallyl alcohol and an aldehyde in the presence of a catalytic amount of cerium triflate, the direct stereoselective formation of tetrahydropyranol derivatives in ionic liquid is reported.

    SOLVENT-FREE PREPARATION OF IONIC LIQUIDS USING A HOUSEHOLD MICROWAVE OVEN

    EPA Science Inventory

    An efficient solventless protocol for the preparation of a wide variety of ionic liquids is described which requires a simple exposure of admixed 1-methylimidazole and alkyl halides to microwave irradiation in open glass containers. The details of this clean process using a commo...

  6. Filling environmental data gaps with QSPR for ionic liquids: Modeling n-octanol/water coefficient.

    PubMed

    Rybinska, Anna; Sosnowska, Anita; Grzonkowska, Monika; Barycki, Maciej; Puzyn, Tomasz

    2016-02-13

    Ionic liquids (ILs) form a wide group of compounds characterized by specific properties that allow using ILs in different fields of science and industry. Regarding that the growing production and use of ionic liquids increase probability of their emission to the environment, it is important to estimate the ability of these compounds to spread in the environment. One of the most important parameters that allow evaluating environmental mobility of compound is n-octanol/water partition coefficient (KOW). Experimental measuring of the KOW values for a large number of compounds could be time consuming and costly. Instead, computational predictions are nowadays being used more often. The paper presents new Quantitative Structure-Property Relationship (QSPR) model that allows predicting the logarithmic values of KOW for 335 ILs, for which the experimentally measured values had been unavailable. We also estimated bioaccumulation potential and point out which group of ILs could have negative impact on environment.

  7. Ionic Liquids to Replace Hydrazine

    NASA Technical Reports Server (NTRS)

    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.

  8. Long range electrostatic forces in ionic liquids.

    PubMed

    Gebbie, Matthew A; Smith, Alexander M; Dobbs, Howard A; Lee, Alpha A; Warr, Gregory G; Banquy, Xavier; Valtiner, Markus; Rutland, Mark W; Israelachvili, Jacob N; Perkin, Susan; Atkin, Rob

    2017-01-19

    Ionic liquids are pure salts that are liquid under ambient conditions. As liquids composed solely of ions, the scientific consensus has been that ionic liquids have exceedingly high ionic strengths and thus very short Debye screening lengths. However, several recent experiments from laboratories around the world have reported data for the approach of two surfaces separated by ionic liquids which revealed remarkable long range forces that appear to be electrostatic in origin. Evidence has accumulated demonstrating long range surface forces for several different combinations of ionic liquids and electrically charged surfaces, as well as for concentrated mixtures of inorganic salts in solvent. The original interpretation of these forces, that ionic liquids could be envisioned as "dilute electrolytes," was controversial, and the origin of long range forces in ionic liquids remains the subject of discussion. Here we seek to collate and examine the evidence for long range surface forces in ionic liquids, identify key outstanding questions, and explore possible mechanisms underlying the origin of these long range forces. Long range surface forces in ionic liquids and other highly concentrated electrolytes hold diverse implications from designing ionic liquids for energy storage applications to rationalizing electrostatic correlations in biological self-assembly.

  9. Radiation Chemistry and Photochemistry of Ionic Liquids

    SciTech Connect

    Wishart, J.F.; Takahaski, K.

    2010-12-01

    As our understanding of ionic liquids and their tunable properties has grown, it is possible to see many opportunities for ionic liquids to contribute to the sustainable use of energy. The potential safety and environmental benefits of ionic liquids, as compared to conventional solvents, have attracted interest in their use as processing media for the nuclear fuel cycle. Therefore, an understanding of the interactions of ionizing radiation 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. This article provides a brief introduction to ionic liquids and their interesting properties, and recent advances in the radiation chemistry and photochemistry of ionic liquids. In this article, we will mainly focus on excess electron dynamics and radical reaction dynamics. Because solvation dynamics processes in ionic liquids are much slower than in molecular solvents, one of the distinguishing characteristics is that pre-solvated electrons play an important role in ionic liquid radiolysis. It will be also shown that the reaction dynamics of radical ions is significantly different from that observed in molecular solvents because of the Coulombic screening effects and electrostatic interactions in ionic liquids.

  10. Influence of methyl and propyl groups on the vibrational spectra of two imidazolium ionic liquids and their non-ionic precursors

    NASA Astrophysics Data System (ADS)

    Haddad, Boumediene; Mokhtar, Drai; Goussem, Mimanne; Belarbi, El-habib; Villemin, Didier; Bresson, Serge; Rahmouni, Mustapha; Dhumal, Nilesh R.; Kim, Hyung J.; Kiefer, Johannes

    2017-04-01

    Imidazolium-based ionic liquids (ILs) are usually synthesized using non-ionic imidazole compounds as precursors. While the ILs have been extensively studied in the past, the precursors was not paid much attention to. The structural analysis of the precursors, however, may offer an opportunity to better understand the behavior of the ionic compounds of interest. In this paper, a comparative study of two ionic liquids and their imidazole precursors is presented. The precursors 1-methylimidazole [1-MIM] and 1,2-dimethylimidazole [1,2-DMIM] are compared in order to explain the influences of the methyl group at the C(2) position (methylation). Since the imidazole compounds are non-ionic, the spectroscopic properties of [1-MIM] and [1,2-DMIM] are not affected by cation-anion interactions. In addition, the products obtained by alkylation using propyl iodide leading to the corresponding IL compounds 1-methyl-3-propylimidazolium iodide [1-MPrIM+][I-] and 1,2-dimethyl-3-propylimidazolium iodide [1,2-DMPrIM+][I-] were studied. For this purpose, vibrational spectroscopy in terms of FT-Raman and FTIR in the wavenumber range from [45 to 3500 cm-1] and from [600 to 4000 cm-1], respectively, was performed. Moreover, to aid the spectral assignment, density functional theory (DFT) calculations were carried out. The aim was to investigate the vibrational structure, to understand the effects of the propyl group at the N(3) and of the methyl group at the C(2) position, and to analyze the resulting cation-anion interactions. The data indicate that the iodide ion predominantly interacts with the C(2)sbnd H group via hydrogen bonding. Upon methylation, the C(4/5)sbnd H moiety becomes the main interaction site. However, an interaction takes place only with one of the two hydrogen atoms resulting in a split of the initially degenerate CH stretching modes.

  11. DETERMINATION OF HENRY'S LAW CONSTANTS FOR VOCS IN ROOM TEMPERATURE IONIC LIQUIDS

    EPA Science Inventory

    Ionic liquids (ILs) have been shown to be a newer medium for a wide variety of chemical reactions and are considered as the potential replacements for traditional volatile organic solvents. However, the separation and recovery of organic compounds from ILs has not been systematic...

  12. The phytotoxicity of ionic liquids from natural pool of (-)-menthol with tetrafluoroborate anion.

    PubMed

    Biczak, Robert; Pawłowska, Barbara; Feder-Kubis, Joanna

    2015-08-01

    Over the last several decades, ionic liquids have become a promising alternative to conventional organic solvents. Initially, ionic liquids were described as "environmentally friendly" substances. However, the results of numerous studies proved that the effects of these compounds on individual ecosystems might be adverse. The presented paper discusses the effect of ionic salts containing natural chiral substituent: (1R,2S,5R)-(-)-menthol in cation and a tetrafluoroborate anion of a general formula of [Cn-Im-Men][BF4] of implementation into the soil on the growth of spring barley and common radish in their early development stages. The obtained results showed that the greatest phytotoxicity was exhibited by ionic liquids containing substituents with the smallest possible number of carbon atoms. The further increase in the length of the chain did not increase the toxicity of these salts for terrestrial plants. Moreover, a compound with a substituent having a chain length of 11 carbon atoms was found to be non-toxic to common radish. The experiment under discussion showed also the effect of these tetrafluoroborates, used in the form of spray, on the development of common sorrel, gallant soldier and white goosefoot. The tests carried out also showed that the most toxic were the compounds with 1 and 3 carbon atoms. The phytotoxicity of tetrafluoroborates was positively correlated with the concentration of these compounds in the soil and was dependent on the genetic features of the genres and varieties of plants used in the experiment.

  13. A Simple "Tubeless" Telescope

    ERIC Educational Resources Information Center

    Straulino, S.; Bonechi, L.

    2010-01-01

    Two lenses make it possible to create a simple telescope with quite large magnification. The set-up is very simple and can be reproduced in schools, provided the laboratory has a range of lenses with different focal lengths. In this article, the authors adopt the Keplerian configuration, which is composed of two converging lenses. This instrument,…

  14. Simple Machine Junk Cars

    ERIC Educational Resources Information Center

    Herald, Christine

    2010-01-01

    During the month of May, the author's eighth-grade physical science students study the six simple machines through hands-on activities, reading assignments, videos, and notes. At the end of the month, they can easily identify the six types of simple machine: inclined plane, wheel and axle, pulley, screw, wedge, and lever. To conclude this unit,…

  15. On the ideality of binary mixtures of ionic liquids.

    PubMed

    Brüssel, Marc; Brehm, Martin; Pensado, Alfonso S; Malberg, Friedrich; Ramzan, Muhammad; Stark, Annegret; Kirchner, Barbara

    2012-10-14

    In this work, structural and dynamical properties of the binary mixture of 1-ethyl-3-methyl-imidazolium chloride and 1-ethyl-3-methyl-imidazolium thiocyanate are investigated from ab initio molecular dynamics simulations and compared to the pure ionic liquids. Furthermore, the binary mixture is simulated with two different densities to gain insight into how the selected density affects the different properties. In addition, a simple NMR experiment is carried out to investigate the changes of the chemical shifts of the hydrogen atoms due to the composition of the mixture.

  16. Intrinsic low thermal conductivity in weakly ionic rocksalt structures

    DOE PAGES

    Zhang, Yi; Dong, Jianjun; Kent, Paul R. C.; ...

    2015-07-06

    A fundamental challenge in thermoelectric (TE) material research is meeting the simultaneous requirements of high carrier mobility and low thermal conductivity. Simple crystal structures are ideal for maintaining high carrier mobility, but they usually have high thermal conductivity. In this paper, we show by first-principles lattice dynamics and Boltzmann transport calculations that weakly ionic rocksalt structures exhibit strong lattice anharmonicity and low acoustic-phonon group velocity, which combine to produce intrinsic low thermal conductivity. Finally, we unveil microscopic mechanisms that explain experimental observations and provide insights for TE material design and discovery.

  17. Determination of sulfonamides in butter samples by ionic liquid magnetic bar liquid-phase microextraction high-performance liquid chromatography.

    PubMed

    Wu, Lijie; Song, Ying; Hu, Mingzhu; Xu, Xu; Zhang, Hanqi; Yu, Aimin; Ma, Qiang; Wang, Ziming

    2015-01-01

    A novel, simple, and environmentally friendly pretreatment method, ionic liquid magnetic bar liquid-phase microextraction, was developed for the determination of sulfonamides in butter samples by high-performance liquid chromatography. The ionic liquid magnetic bar was prepared by inserting a stainless steel wire into the hollow of a hollow fiber and immobilizing ionic liquid in the micropores of the hollow fiber. In the extraction process, the ionic liquid magnetic bars were used to stir the mixture of sample and extraction solvent and enrich the sulfonamides in the mixture. After extraction, the analyte-adsorbed ionic liquid magnetic bars were readily isolated with a magnet from the extraction system. It is notable that the present method was environmentally friendly since water and only several microliters of ionic liquid were used in the whole extraction process. Several parameters affecting the extraction efficiency were investigated and optimized, including the type of ionic liquid, sample-to-extraction solvent ratio, the number of ionic liquid magnetic bars, extraction temperature, extraction time, salt concentration, stirring speed, pH of the extraction solvent, and desorption conditions. The recoveries were in the range of 73.25-103.85 % and the relative standard deviations were lower than 6.84 %. The experiment results indicated that the present method was effective for the extraction of sulfonamides in high-fat content samples.

  18. Chiral ionic liquids: synthesis, properties, and enantiomeric recognition.

    PubMed

    Yu, Shaofang; Lindeman, Sergey; Tran, Chieu D

    2008-04-04

    We have synthesized a series of structurally novel chiral ionic liquids which have a either chiral cation, chiral anion, or both. Cations are an imidazolium group, while anions are based on a borate ion with spiral structure and chiral substituents. Both (or all) stereoisomeric forms of each compound in the series can be readily synthesized in optically pure form by a simple one-step process from commercially available reagents. In addition to the ease of preparation, most of the chiral ILs in this series are liquid at room temperature with a solid to liquid transformation temperature as low as -70 degrees C and have relatively high thermal stability (up to at least 300 degrees C). Circular dichroism and X-ray crystallographic results confirm that the reaction to form the chiral spiral borate anion is stereospecific, namely, only one of two possible spiral stereoisomers was formed. Results of NMR studies including 1H{15N} heteronuclear single quantum coherence (HSQC) show that these chiral ILs exhibit intramolecular as well as intermolecular enantiomeric recognition. Intramolecularly, the chiral anion of an IL was found to exhibit chiral recognition toward the cation. Specifically, for a chiral IL composing with a chiral anion and a racemic cation, enantiomeric recognition of the chiral anion toward both enantiomers of the cation lead to pronounced differences in the NMR bands of the cation enantiomers. The chiral recognition was found to be dependent on solvent dielectric constant, concentration, and structure of the ILs. Stronger enantiomeric recognition was found in solvent with relatively lower dielectric constants (CDCl3 compared to CD3CN) and at higher concentration of ILs. Also, stronger chiral recognition was found for anions with a relatively larger substituent group (e.g., chiral anion with a phenylmethyl group exhibits stronger chiral recognition compared to that with a phenyl group, and an anion with an isobutyl group has the weakest chiral recognition

  19. Hydrogen fluoride capture by imidazolium acetate ionic liquid

    NASA Astrophysics Data System (ADS)

    Chaban, Vitaly

    2015-04-01

    Extraction of hydrofluoric acid (HF) from oils is a drastically important problem in petroleum industry, since HF causes quick corrosion of pipe lines and brings severe health problems to humanity. Some ionic liquids (ILs) constitute promising scavenger agents thanks to strong binding to polar compounds and tunability. PM7-MD simulations and hybrid density functional theory are employed here to consider HF capture ability of ILs. Discussing the effects and impacts of the cation and the anion separately and together, we evaluate performance of imidazolium acetate and outline systematic search guidelines for efficient adsorption and extraction of HF.

  1. Boron compounds as anion binding agents for nonaqueous battery electrolytes

    DOEpatents

    Lee, Hung Sui; Yang, Xia-Oing; McBreen, James; Xiang, Caili

    2000-02-08

    Novel fluorinated boron-based compounds which act as anion receptors in non-aqueous battery electrolytes are provided. When added to non-aqueous battery electrolytes, the fluorinated boron-based compounds of the invention enhance ionic conductivity and cation transference number of non-aqueous electrolytes. The fluorinated boron-based anion receptors include borane and borate compounds bearing different fluorinated alkyl and aryl groups.

  2. Transport of ferrihydrite nanoparticles in saturated porous media: role of ionic strength and flow rate.

    PubMed

    Tosco, Tiziana; Bosch, Julian; Meckenstock, Rainer U; Sethi, Rajandrea

    2012-04-03

    The use of nanoscale ferrihydrite particles, which are known to effectively enhance microbial degradation of a wide range of contaminants, represents a promising technology for in situ remediation of contaminated aquifers. Thanks to their small size, ferrihydrite nanoparticles can be dispersed in water and directly injected into the subsurface to create reactive zones where contaminant biodegradation is promoted. Field applications would require a detailed knowledge of ferrihydrite transport mechanisms in the subsurface, but such studies are lacking in the literature. The present study is intended to fill this gap, focusing in particular on the influence of flow rate and ionic strength on particle mobility. Column tests were performed under constant or transient ionic strength, including injection of ferrihydrite colloidal dispersions, followed by flushing with particle-free electrolyte solutions. Particle mobility was greatly affected by the salt concentration, and particle retention was almost irreversible under typical salt content in groundwater. Experimental results indicate that, for usual ionic strength in European aquifers (2 to 5 mM), under natural flow condition ferrihydrite nanoparticles are likely to be transported for 5 to 30 m. For higher ionic strength, corresponding to contaminated aquifers, (e.g., 10 mM) the travel distance decreases to few meters. A simple relationship is proposed for the estimation of travel distance with changing flow rate and ionic strength. For future applications to aquifer remediation, ionic strength and injection rate can be used as tuning parameters to control ferrihydrite mobility in the subsurface and therefore the radius of influence during field injections.

  3. Microwave-assisted preparation of poly(ionic liquids)-modified magnetic nanoparticles for pesticide extraction.

    PubMed

    Zhang, Ruizhe; Su, Ping; Yang, Lu; Yang, Yi

    2014-06-01

    Novel poly(ionic liquids) were synthesized and immobilized on prepared magnetic nanoparticles, which were used to extract pesticides from fruit and vegetable samples by dispersive solid-phase extraction prior to high-performance liquid chromatography analysis. Compared with monomeric ionic liquids, poly(ionic liquids) have a larger effective contact area and higher viscosity, so they can achieve higher extraction efficiency and be used repeatedly without a decrease in analyte recovery. The immobilized poly(ionic liquids) were rapidly separated from the sample matrix, providing a simple approach for sample pretreatment. The nature and volume of the desorption solvent and amount of poly(ionic liquid)-modified magnetic material were optimized for the extraction process. Under optimum conditions, calibration curves were linear (R(2) > 0.9988) for pesticide concentrations in the range of 0.100-10.000 μg/L. The relative standard deviations for repeated determinations of the four analytes were 2.29-3.31%. The limits of detection and quantification were 0.29-0.88 and 0.97-2.93 μg/L, respectively. Our results demonstrate that the developed poly(ionic liquid)-modified material is an effective absorbent to extract pesticides from fruit and vegetable samples.

  4. Superconductivity Series in Transition Metal Dichalcogenides by Ionic Gating.

    PubMed

    Shi, Wu; Ye, Jianting; Zhang, Yijin; Suzuki, Ryuji; Yoshida, Masaro; Miyazaki, Jun; Inoue, Naoko; Saito, Yu; Iwasa, Yoshihiro

    2015-08-03

    Functionalities of two-dimensional (2D) crystals based on semiconducting transition metal dichalcogenides (TMDs) have now stemmed from simple field effect transistors (FETs) to a variety of electronic and opto-valleytronic devices, and even to superconductivity. Among them, superconductivity is the least studied property in TMDs due to methodological difficulty accessing it in different TMD species. Here, we report the systematic study of superconductivity in MoSe2, MoTe2 and WS2 by ionic gating in different regimes. Electrostatic gating using ionic liquid was able to induce superconductivity in MoSe2 but not in MoTe2 because of inefficient electron accumulation limited by electronic band alignment. Alternative gating using KClO4/polyethylene glycol enabled a crossover from surface doping to bulk doping, which induced superconductivities in MoTe2 and WS2 electrochemically. These new varieties greatly enriched the TMD superconductor families and unveiled critical methodology to expand the capability of ionic gating to other materials.

  5. Superconductivity Series in Transition Metal Dichalcogenides by Ionic Gating

    PubMed Central

    Shi, Wu; Ye, Jianting; Zhang, Yijin; Suzuki, Ryuji; Yoshida, Masaro; Miyazaki, Jun; Inoue, Naoko; Saito, Yu; Iwasa, Yoshihiro

    2015-01-01

    Functionalities of two-dimensional (2D) crystals based on semiconducting transition metal dichalcogenides (TMDs) have now stemmed from simple field effect transistors (FETs) to a variety of electronic and opto-valleytronic devices, and even to superconductivity. Among them, superconductivity is the least studied property in TMDs due to methodological difficulty accessing it in different TMD species. Here, we report the systematic study of superconductivity in MoSe2, MoTe2 and WS2 by ionic gating in different regimes. Electrostatic gating using ionic liquid was able to induce superconductivity in MoSe2 but not in MoTe2 because of inefficient electron accumulation limited by electronic band alignment. Alternative gating using KClO4/polyethylene glycol enabled a crossover from surface doping to bulk doping, which induced superconductivities in MoTe2 and WS2 electrochemically. These new varieties greatly enriched the TMD superconductor families and unveiled critical methodology to expand the capability of ionic gating to other materials. PMID:26235962

  6. Can the Transport Properties of Molten Salts and Ionic Liquids Be Used To Determine Ion Association?

    PubMed

    Harris, Kenneth R

    2016-12-01

    There have long been arguments supporting the concept of ion association in molten salts and ionic liquids, largely based on differences between the conductivity and that predicted from self-diffusion coefficients by the Nernst-Einstein equation for noninteracting ions. It is known from molecular dynamics simulations that even simple models based on charged hard spheres show such a difference due to the (anti)-correlation of ion motions. Formally this is expressed as a difference between the velocity cross-correlation coefficient of the oppositely charged ions and the mean of those for the two like-charged ions. This article examines molten salt and ionic liquid transport property data, comparing simple and model associated salts (ZnCl2, PbCl2, and TlCl) including weakly dissociated molecular liquids (H2O, HCOOH, H2SO4). Analysis employing Laity resistance coefficients (rij) shows that the common ion-association rationalization is flawed, consistent with recent direct measurements of the degree of ionicity in ionic liquid chlorides and with theoretical studies. However, the protic ionic liquids [PyrOMe][BF4] and [DBUH][CH3SO3] have larger than usual NE deviation parameters (>0.5), and large negative like-ion rii, analogous to those of ZnCl2. Structural, spectroscopic, and theoretical studies are suggested to determine whether these are indeed genuine examples of association.

  7. Illustrating the Concept of Sparingly Soluble Salts Using Various Copper Compounds. A Classroom Demonstration

    NASA Astrophysics Data System (ADS)

    O'Sullivan, Daniel W.; Crouch, Collier C.

    2009-02-01

    Many students in general and advanced chemistry courses have difficulty understanding differences in solubility by inspecting changing values of the solubility product constants for sparingly soluble salts. In this demonstration, the concepts involved in understanding the solubility of sparingly soluble salts are illustrated visually. Utilizing bathocuproinedisulfonic acid in a mixed reducing reagent to complex copper(I), we are able to demonstrate to the naked eye copper(I) and copper(II) concentrations resulting from the dissolution of a variety of sparingly soluble copper compounds. The actual concentration of copper in solution can be determined using this visual demonstration in combination with a spectrophotometer. This demonstration visually confirms copper concentrations in the range of 1 x 10 -3 to 1 x 10 -6 M. Calculated solubilities based on a simple algorithm, neglecting secondary equilibria, ion-pair formation, and ionic effects, are in reasonable agreement with the measured solubilities.

  8. Facilitated Ion Transport in Smectic Ordered Ionic Liquid Crystals.

    PubMed

    Lee, Jin Hong; Han, Kee Sung; Lee, Je Seung; Lee, Albert S; Park, Seo Kyung; Hong, Sung Yun; Lee, Jong-Chan; Mueller, Karl T; Hong, Soon Man; Koo, Chong Min

    2016-11-01

    A novel ionic mixture of an imidazolium-based room-temperature ionic liquid containing ethylene-oxide-functionalized phosphite anions is fabricated, which, when doped with lithium salt, self-assembles into a smectic-ordered ionic liquid crystal through Coulombic interactions between the ion species. Interestingly, the smectic order in the ionic-liquid-crystal ionogel facilitates ionic transport.

  9. Early Events in Ionic Liquid Radiation Chemistry

    SciTech Connect

    Wishart, J.F.; Cook, A.; Rimmer, R.D.; Gohdo, M.

    2010-09-14

    Ionic liquids are interesting and useful materials whose solvation time scales are up to thousands of times longer than in conventional solvents. The extended lifetimes of pre-solvated electrons and other energetic species in ionic liquids has profound consequences for the radiolytic product distributions and reactivity patterns. We use a newly developed, multiplexed variation of pulse-probe spectroscopy to measure the kinetics of the early dynamical and reactive events in ionic liquids.

  10. Highly Selective Ionic Block Copolymer Membranes

    DTIC Science & Technology

    2010-11-10

    commonly used ionic polymer membrane in fuel cells ) as a function of methanol solution concentration using time-resolved FTIR-ATR spectroscopy. This...this field of study. These results suggest that methanol fuel cell performance and efficiency can be improved by developing new ionic polymers that...methanol sorption in the membrane and not diffusion. The typical assumption in ionic polymer development for the methanol fuel cell is that the diffusion

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

    SciTech Connect

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

    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.

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

    PubMed

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

    2014-02-20

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

  13. Carbon dioxide capture by aminoalkyl imidazolium-based ionic liquid: a computational investigation.

    PubMed

    Chen, Jie-Jie; Li, Wen-Wei; Li, Xue-Liang; Yu, Han-Qing

    2012-04-07

    Efficient technologies/processes for CO(2) capture are greatly desired, and ionic liquids are recognized as promising materials for this purpose. However, the mechanisms for selectively capturing CO(2) by ionic liquids are unclear. In this study, the interactions between CO(2) and 1-n-amino-alkyl-3-methyl-imidazolium tetrafluoroborate, an amino imidazolium ionic liquid (AIIL), in its CO(2) capturing process, are elucidated with both quantum chemistry and molecular dynamics approaches on the molecular level. The effects of the straight aminoalkyl chain length in imidazolium-based cations on CO(2) capture are explored, and thereby the factors governing CO(2) capture for this ionic liquid family, e.g., ionic liquid structure, charge distribution, intermolecular interactions, thermodynamic properties and absorption kinetics, are analyzed. Molecular dynamics simulations are used to study the diffusion of the involved compounds and liquid structures of the CO(2)-AIIL systems. The results show that the amino-alkyl chain length plays an important role in governing the absorption properties of AIILs, including the free energies of absorption, equilibrium constants, desorption temperature, absorption rate constants, diffusion coefficients, and organization of CO(2) around cations and anions. This study provides useful information about rational design of ionic liquids for efficient CO(2) capture.

  14. Simple Bond Cleavage

    SciTech Connect

    Gary S. Groenewold

    2005-08-01

    Simple bond cleavage is a class of fragmentation reactions in which a single bond is broken, without formation of new bonds between previously unconnected atoms. Because no bond making is involved, simple bond cleavages are endothermic, and activation energies are generally higher than for rearrangement eliminations. The rate of simple bond cleavage reactions is a strong function of the internal energy of the molecular ion, which reflects a loose transition state that resembles reaction products, and has a high density of accessible states. For this reason, simple bond cleavages tend to dominate fragmentation reactions for highly energized molecular ions. Simple bond cleavages have negligible reverse activation energy, and hence they are used as valuable probes of ion thermochemistry, since the energy dependence of the reactions can be related to the bond energy. In organic mass spectrometry, simple bond cleavages of odd electron ions can be either homolytic or heterolytic, depending on whether the fragmentation is driven by the radical site or the charge site. Simple bond cleavages of even electron ions tend to be heterolytic, producing even electron product ions and neutrals.

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

    PubMed

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

    2009-01-15

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

  16. Ionic-liquid mediated olefin hydroboration and heteroatom insertion reactions, and the development of template routes to non-oxide ceramic nano- and micro-structures

    NASA Astrophysics Data System (ADS)

    Kusari, Upal

    The goal of the work described in this dissertation was two-fold: (1) To use the unique properties of ionic liquids to develop new synthetic routes to boron-containing molecules including substituted decaboranes, ortho-carboranes and chalcogeno-boranes, and (2) to combine newly developed chemical precursors with template routes to fabricate the non-oxide ceramics boron carbide, silicon carbide and boron nitride on the micro- and nano-scales. The first application of ionic liquid and related salt systems to the hydroboration of a variety of olefins with the polyborane cage B10H 14, leading to the syntheses of functionalized decaborane clusters, 6-R-B10H13, was demonstrated. The decaborane olefin-hydroboration reaction was found to proceed with a wide variety of functional olefins, including, alkenyl, halide, phenyl, ether, ester, pinacolborane, ketone and alcohol-containing olefins. These reactions provide a general, simple, one-pot and high-yield alternative route to functional boranes. The functional decaboranes were then converted by another ionic liquid mediated reaction, to its ortho -carborane derivatives 3-R-1,2-Et2C2B 10H9. Experimental and computational studies of the hydroboration mechanism suggest that the ionic liquid induced the formation of the B 10H13- anion which behaved as an electrophile in the olefin-hydroboration reaction. The unique properties of ionic liquids were also found to be useful in mediating the insertion of chalcogen heteroatoms into the borane clusters nido-B10H14, nido-5,6-C2B8H12 and arachno -4-CB8H14 and led to the improved syntheses of the known compounds nido-7-SB10H12, nido-7-SeB10H12, nido-7,9,10-SC 2B8H10, nido-7,9,10-SeC 2B8H10 and arachno-6,9-CSB 8H12, as well as the synthesis of the new 10-vertex selena-monocarbaborane arachno-6,9-CSeB8H12 (˜40% yield). The second part of the thesis demonstrated that newly developed chemical precursors can be used in conjunction with silica bead and diatom frustule templates to generate

  17. Thermodynamics and micro heterogeneity of ionic liquids.

    PubMed

    Gomes, Margarida F Costa; Lopes, J N Canongia; Padua, A A H

    2010-01-01

    The high degree of organisation in the fluid phase of room-temperature ionic liquids has major consequences on their macroscopic properties, namely on their behaviour as solvents. This nanoscale self-organisation is the result of an interplay between two types of interaction in the liquid phase - Coulomb and van der Waals - that eventually leads to the formation of medium-range structures and the recognition of some ionic liquids as composed of a high-charge density, cohesive network permeated by low-charge density regions.In this chapter, the structure of the ionic liquids will be explored and some of their consequences to the properties of ionic liquids analyzed.

  18. Ionic Liquid-Based Ultrasonic-Assisted Extraction of Secoisolariciresinol Diglucoside from Flaxseed (Linum usitatissimum L.) with Further Purification by an Aqueous Two-Phase System.

    PubMed

    Tan, Zhi-Jian; Wang, Chao-Yun; Yang, Zi-Zhen; Yi, Yong-Jian; Wang, Hong-Ying; Zhou, Wan-Lai; Li, Fen-Fang

    2015-09-30

    In this work, a two-step extraction methodology of ionic liquid-based ultrasonic-assisted extraction (IL-UAE) and ionic liquid-based aqueous two-phase system (IL-ATPS) was developed for the extraction and purification of secoisolariciresinol diglucoside (SDG) from flaxseed. In the IL-UAE step, several kinds of ILs were investigated as the extractants, to identify the IL that affords the optimum extraction yield. The extraction conditions such as IL concentration, ultrasonic irradiation time, and liquid-solid ratio were optimized using response surface methodology (RSM). In the IL-ATPS step, ATPS formed by adding kosmotropic salts to the IL extract was used for further separation and purification of SDG. The most influential parameters (type and concentration of salt, temperature, and pH) were investigated to obtain the optimum extraction efficiency. The maximum extraction efficiency was 93.35% under the optimal conditions of 45.86% (w/w) IL and 8.27% (w/w) Na₂SO₄ at 22 °C and pH 11.0. Thus, the combination of IL-UAE and IL-ATPS makes up a simple and effective methodology for the extraction and purification of SDG. This process is also expected to be highly useful for the extraction and purification of bioactive compounds from other important medicinal plants.

  19. Disinfection of Spacecraft Potable Water Systems by Passivation with Ionic Silver

    NASA Technical Reports Server (NTRS)

    Birmele, Michele N.; McCoy, LaShelle e.; Roberts, Michael S.

    2011-01-01

    Microbial growth is common on wetted surfaces in spacecraft environmental control and life support systems despite the use of chemical and physical disinfection methods. Advanced control technologies are needed to limit microorganisms and increase the reliability of life support systems required for long-duration human missions. Silver ions and compounds are widely used as antimicrobial agents for medical applications and continue to be used as a residual biocide in some spacecraft water systems. The National Aeronautics and Space Administration (NASA) has identified silver fluoride for use in the potable water system on the next generation spacecraft. Due to ionic interactions between silver fluoride in solution and wetted metallic surfaces, ionic silver is rapidly depleted from solution and loses its antimicrobial efficacy over time. This report describes research to prolong the antimicrobial efficacy of ionic silver by maintaining its solubility. Three types of metal coupons (lnconel 718, Stainless Steel 316, and Titanium 6AI-4V) used in spacecraft potable water systems were exposed to either a continuous flow of water amended with 0.4 mg/L ionic silver fluoride or to a static, pre-treatment passivation in 50 mg/L ionic silver fluoride with or without a surface oxidation pre-treatment. Coupons were then challenged in a high-shear, CDC bioreactor (BioSurface Technologies) by exposure to six bacteria previously isolated from spacecraft potable water systems. Continuous exposure to 0.4 mg/L ionic silver over the course of 24 hours during the flow phase resulted in a >7-log reduction. The residual effect of a 24-hour passivation treatment in 50 mg/L of ionic silver resulted in a >3-log reduction, whereas a two-week treatment resulted in a >4-log reduction. Results indicate that 0.4 mg/L ionic silver is an effective biocide against many bacteria and that a prepassivation of metal surfaces with silver can provide additional microbial control.

  20. The Relation between Vaporization Enthalpies and Viscosities: Eyring's Theory Applied to Selected Ionic Liquids.

    PubMed

    Bonsa, Anne-Marie; Paschek, Dietmar; Zaitsau, Dzmitry H; Emel'yanenko, Vladimir N; Verevkin, Sergey P; Ludwig, Ralf

    2017-03-08

    Key properties for the use of ionic liquids as electrolytes in batteries are low viscosities, low vapor pressure and high vaporization enthalpies. Whereas the measurement of transport properties is well established, the determination of vaporization enthalpies of these extremely low volatile compounds is still a challenge. At a first glance both properties seem to describe different thermophysical phenomena. However, eighty years ago Eyring suggested a theory which related viscosities and vaporization enthalpies to each other. The model is based on Eyring's theory of absolute reaction rates. Recent attempts to apply Eyring's theory to ionic liquids failed. The motivation of our study is to show that Eyring's theory works, if the assumptions specific for ionic liquids are fulfilled. For that purpose we measured the viscosities of three well selected protic ionic liquids (PILs) at different temperatures. The temperature dependences of viscosities were approximated by the Vogel-Fulcher-Tamann (VFT) relation and extrapolated to the high-temperature regime up to 600 K. Then the VFT-data could be fitted to the Eyring-model. The values of vaporization enthalpies for the three selected PILs predicted by the Eyring model have been very close to the experimental values measured by well-established techniques. We conclude that the Eyring theory can be successfully applied to the chosen set of PILs, if the assumption that ionic pairs of the viscous flow in the liquid and the ionic pairs in the gas phase are similar is fulfilled. It was also noticed that proper transfer of energies can be only derived if the viscosities and the vaporization energies are known for temperatures close to the liquid-gas transition temperature. The idea to correlate easy measurable viscosities of ionic liquids with their vaporization enthalpies opens a new way for a reliable assessment of these thermodynamic properties for a broad range of ionic liquids.

  1. Electrosorptive Detection of Simple Organic Compounds in Liquid Chromatography.

    DTIC Science & Technology

    1987-09-30

    Jehring , Elektrosorpelonsanalyse mit der Wechselstrompolarographle, Akademie-Verlag, Berlin, 1974. 3. F. G. Banica, A. Sadoveanu and C. Patroescu...13. 30. H. Jehring , op. cit., Ch. 11. 31. T. Raxnstad and M. J. Weaver, Anal. Chim. Acta, in press. 32. T. Ramstad and M. J. Weaver, submitted for...Comprehensive Treatise of Electrochemistry, Plenum, New York, 1980, Vol. 1, Ch. 8. 41. H. Jehring , op. cit., Ch. 10. 24 42. Ibid., Cbs. 6 and 10. 43

  2. Identification of Simple and Compound Vowels by First Graders.

    ERIC Educational Resources Information Center

    Wright, Ouida Marina

    The purpose of the study was to determine whether by structuring and sequencing the same monosyllabic CVC, CVVC, and CVCe English words in two different patterns (EI and EII), administered with the same controlled procedures, boys and girls in grade one would be facilitated in detecting, identifying, and discriminating among single vowels and…

  3. A Simple Raman Spectrometer.

    ERIC Educational Resources Information Center

    Blond, J. P.; Boggett, D. M.

    1980-01-01

    Discusses some basic physical ideas about light scattering and describes a simple Raman spectrometer, a single prism monochromator and a multiplier detector. This discussion is intended for British undergraduate physics students. (HM)

  4. Fibrosis and Simple Cysts

    MedlinePlus

    ... caffeine and other stimulants found in coffee, tea, chocolate, and many soft drinks. Studies have not found ... side effects. How do fibrosis and simple cysts affect your risk for breast cancer? Neither fibrosis nor ...

  5. A Simple Water Channel

    ERIC Educational Resources Information Center

    White, A. S.

    1976-01-01

    Describes a simple water channel, for use with an overhead projector. It is run from a water tap and may be used for flow visualization experiments, including the effect of streamlining and elementary building aerodynamics. (MLH)

  6. Early Childhood: Simple Science.

    ERIC Educational Resources Information Center

    Jones, Clare B.; Shafer, Kathryn E.

    1987-01-01

    Encourages teachers to take advantage of the natural curiosity of young children in enhancing their interest in science. Describes four simple activities involving water, living and non-living things, air pollution, and food. (TW)

  7. Simple Machines Simply Put.

    ERIC Educational Resources Information Center

    Kirkwood, James J.

    1994-01-01

    Students explore the workings of the lever, wheel and axle, and the inclined plane as they build simple toys--a bulldozer and a road grader. The project takes four weeks. Diagrams and procedures are included. (PR)

  8. Actinide chemistry in ionic liquids.

    PubMed

    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.

  9. Ionic Structure at Dielectric Interfaces

    NASA Astrophysics Data System (ADS)

    Jing, Yufei

    The behavior of ions in liquids confined between macromolecules determines the outcome of many nanoscale assembly processes in synthetic and biological materials such as colloidal dispersions, emulsions, hydrogels, DNA, cell membranes, and proteins. Theoretically, the macromolecule-liquid boundary is often modeled as a dielectric interface and an important quantity of interest is the ionic structure in a liquid confined between two such interfaces. The knowledge gleaned from the study of ionic structure in such models can be useful in several industrial applications, such as biosensors, lithium-ion batteries double-layer supercapacitors for energy storage and seawater desalination. Electrostatics plays a critical role in the development of such functional materials. Many of the functions of these materials, result from charge and composition heterogeneities. There are great challenges in solving electrostatics problems in heterogeneous media with arbitrary shapes because electrostatic interactions remains unknown but depend on the particular density of charge distributions. Charged molecules in heterogeneous media affect the media's dielectric response and hence the interaction between the charges is unknown since it depends on the media and on the geometrical properties of the interfaces. To determine the properties of heterogeneous systems including crucial effects neglected in classical mean field models such as the hard core of the ions, the dielectric mismatch and interfaces with arbitrary shapes. The effect of hard core interactions accounts properly for short range interactions and the effect of local dielectric heterogeneities in the presence of ions and/or charged molecules for long-range interactions are both analyzed via an energy variational principle that enables to update charges and the medium's response in the same simulation time step. In particular, we compute the ionic structure in a model system of electrolyte confined by two planar dielectric

  10. Simple Ontology Format (SOFT)

    SciTech Connect

    Sorokine, Alexandre

    2011-10-01

    Simple Ontology Format (SOFT) library and file format specification provides a set of simple tools for developing and maintaining ontologies. The library, implemented as a perl module, supports parsing and verification of the files in SOFt format, operations with ontologies (adding, removing, or filtering of entities), and converting of ontologies into other formats. SOFT allows users to quickly create ontologies using only a basic text editor, verify it, and portray it in a graph layout system using customized styles.

  11. Polybenzimidazole compounds

    DOEpatents

    Klaehn, John R [Idaho Falls, ID; Peterson, Eric S [Idaho Falls, ID; Orme, Christopher J [Shelley, ID; Jones, Michael G [Chubbuck, ID; Wertsching, Alan K [Idaho Falls, ID; Luther, Thomas A [Idaho Falls, ID; Trowbridge, Tammy L [Idaho Falls, ID

    2011-11-22

    A PBI compound includes imidazole nitrogens at least a portion of which are substituted with a moiety containing a carbonyl group, the substituted imidazole nitrogens being bonded to carbon of the carbonyl group. At least 85% of the nitrogens may be substituted. The carbonyl-containing moiety may include RCO--, where R is alkoxy or haloalkyl. The PBI compound may exhibit a first temperature marking an onset of weight loss corresponding to reversion of the substituted PBI that is less than a second temperature marking an onset of decomposition of an otherwise identical PBI compound without the substituted moiety. The PBI compound may be included in separatory media. A substituted PBI synthesis method may include providing a parent PBI in a less than 5 wt % solvent solution. Substituting may use more than 5 equivalents in relation to the imidazole nitrogens to be substituted.

  12. Polybenzimidazole compounds

    DOEpatents

    Klaehn, John R.; Peterson, Eric S.; Wertsching, Alan K.; Orme, Christopher J.; Luther, Thomas A.; Jones, Michael G.

    2010-08-10

    A PBI compound that includes imidazole nitrogens, at least a portion of which are substituted with an organic-inorganic hybrid moiety. At least 85% of the imidazole nitrogens may be substituted. The organic-inorganic hybrid moiety may be an organosilane moiety, for example, (R)Me.sub.2SiCH.sub.2--, where R is selected from among methyl, phenyl, vinyl, and allyl. The PBI compound may exhibit similar thermal properties in comparison to the unsubstituted PBI. The PBI compound may exhibit a solubility in an organic solvent greater than the solubility of the unsubstituted PBI. The PBI compound may be included in separatory media. A substituted PBI synthesis method may include providing a parent PBI in a less than 5 wt % solvent solution. Substituting may occur at about room temperature and/or at about atmospheric pressure. Substituting may use at least five equivalents in relation to the imidazole nitrogens to be substituted or, preferably, about fifteen equivalents.

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

    PubMed

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

    2016-01-01

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

  14. Atomic-scale configurations of synchroshear-induced deformation twins in the ionic MnS crystal

    PubMed Central

    Zhou, Y. T.; Xue, Y. B.; Chen, D.; Wang, Y. J.; Zhang, B.; Ma, X. L.

    2014-01-01

    Deformation twinning was thought as impossible in ionic compounds with rock-salt structure due to the charge effect on {111} planes. Here we report the presence and formation mechanism of deformation {111} twins in the rock-salt manganese sulphide (MnS) inclusions embedded in a hot-rolled stainless steel. Based on the atomic-scale mapping under aberration-corrected scanning transmission electron microscopy, a dislocation-based mechanism involved two synchronized shear on adjacent atomic layers is proposed to describe the dislocation glide and consequently twinning formation. First-principles calculations of the energy barriers for twinning formation in MnS and comparing with that of PbS and MgO indicate the distinct dislocation glide scheme and deformation behaviors for the rock-salt compounds with different ionicities. This study may improve our understanding of the deformation mechanisms of rock-salt crystals and other ionic compounds. PMID:24874022

  15. Atomic-scale configurations of synchroshear-induced deformation twins in the ionic MnS crystal.

    PubMed

    Zhou, Y T; Xue, Y B; Chen, D; Wang, Y J; Zhang, B; Ma, X L

    2014-05-30

    Deformation twinning was thought as impossible in ionic compounds with rock-salt structure due to the charge effect on {111} planes. Here we report the presence and formation mechanism of deformation {111} twins in the rock-salt manganese sulphide (MnS) inclusions embedded in a hot-rolled stainless steel. Based on the atomic-scale mapping under aberration-corrected scanning transmission electron microscopy, a dislocation-based mechanism involved two synchronized shear on adjacent atomic layers is proposed to describe the dislocation glide and consequently twinning formation. First-principles calculations of the energy barriers for twinning formation in MnS and comparing with that of PbS and MgO indicate the distinct dislocation glide scheme and deformation behaviors for the rock-salt compounds with different ionicities. This study may improve our understanding of the deformation mechanisms of rock-salt crystals and other ionic compounds.

  16. Ionic liquids as transesterification catalysts: applications for the synthesis of linear and cyclic organic carbonates

    PubMed Central

    Perosa, Alvise; Guidi, Sandro; Cattelan, Lisa

    2016-01-01

    Summary The use of ionic liquids (ILs) as organocatalysts is reviewed for transesterification reactions, specifically for the conversion of nontoxic compounds such as dialkyl carbonates to both linear mono-transesterification products or alkylene carbonates. An introductory survey compares pros and cons of classic catalysts based on both acidic and basic systems, to ionic liquids. Then, innovative green syntheses of task-specific ILs and their representative applications are introduced to detail the efficiency and highly selective outcome of ILs-catalyzed transesterification reactions. A mechanistic hypothesis is discussed by the concept of cooperative catalysis based on the dual (electrophilic/nucleophilic) activation of reactants. PMID:27829898

  17. Ionic liquids as transesterification catalysts: applications for the synthesis of linear and cyclic organic carbonates.

    PubMed

    Selva, Maurizio; Perosa, Alvise; Guidi, Sandro; Cattelan, Lisa

    2016-01-01

    The use of ionic liquids (ILs) as organocatalysts is reviewed for transesterification reactions, specifically for the conversion of nontoxic compounds such as dialkyl carbonates to both linear mono-transesterification products or alkylene carbonates. An introductory survey compares pros and cons of classic catalysts based on both acidic and basic systems, to ionic liquids. Then, innovative green syntheses of task-specific ILs and their representative applications are introduced to detail the efficiency and highly selective outcome of ILs-catalyzed transesterification reactions. A mechanistic hypothesis is discussed by the concept of cooperative catalysis based on the dual (electrophilic/nucleophilic) activation of reactants.

  18. Synthesis and ionic liquid gating of hexagonal WO{sub 3} thin films

    SciTech Connect

    Wu, Phillip M. E-mail: beasley@stanford.edu; Munakata, Ko; Hammond, R. H.; Geballe, T. H.; Beasley, M. R. E-mail: beasley@stanford.edu; Ishii, Satoshi; Tanabe, Kenji; Tokiwa, Kazuyasu

    2015-01-26

    Via thin film deposition techniques, the meta-stable in bulk crystal hexagonal phase of tungsten oxide (hex-WO{sub 3}) is stabilized as a thin film. The hex-WO{sub 3} structure is potentially promising for numerous applications and is related to the structure for superconducting compounds found in WO{sub 3}. Utilizing ionic liquid gating, carriers were electrostatically induced in the films and an insulator-to-metal transition is observed. These results show that ionic liquid gating is a viable technique to alter the electrical transport properties of WO{sub 3}.

  19. The antimicrobial potential of ionic liquids: A source of chemical diversity for infection and biofilm control.

    PubMed

    Pendleton, Jack Norman; Gilmore, Brendan F

    2015-08-01

    Although described almost a century ago, interest in ionic liquids has flourished in the last two decades, with significant advances in the understanding of their chemical, physical and biological property sets driving their widespread application across multiple and diverse research areas. Significant progress has been made through the contributions of numerous research groups detailing novel libraries of ionic liquids, often 'task-specific' designer solvents for application in areas as diverse as separation technology, catalysis and bioremediation. Basic antimicrobial screening has often been included as a surrogate indication of the environmental impact of these compounds widely regarded as 'green' solvents. Obviating the biological properties, specifically toxicity, of these compounds has obstructed their potential application as sophisticated designer biocides. A recent tangent in ionic liquids research now aims to harness tuneable biological properties of these compounds in the design of novel potent antimicrobials, recognising their unparalleled flexibility for chemical diversity in a severely depleted antimicrobial arsenal. This review concentrates primarily on the antimicrobial potential of ionic liquids and aims to consolidate contemporary microbiological background information, assessment protocols and future considerations necessary to advance the field in light of the urgent need for antimicrobial innovation.

  20. Ionic liquid tunes microemulsion curvature.

    PubMed

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

    2009-02-17

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

  1. Strategy as simple rules.

    PubMed

    Eisenhardt, K M; Sull, D N

    2001-01-01

    The success of Yahoo!, eBay, Enron, and other companies that have become adept at morphing to meet the demands of changing markets can't be explained using traditional thinking about competitive strategy. These companies have succeeded by pursuing constantly evolving strategies in market spaces that were considered unattractive according to traditional measures. In this article--the third in an HBR series by Kathleen Eisenhardt and Donald Sull on strategy in the new economy--the authors ask, what are the sources of competitive advantage in high-velocity markets? The secret, they say, is strategy as simple rules. The companies know that the greatest opportunities for competitive advantage lie in market confusion, but they recognize the need for a few crucial strategic processes and a few simple rules. In traditional strategy, advantage comes from exploiting resources or stable market positions. In strategy as simple rules, advantage comes from successfully seizing fleeting opportunities. Key strategic processes, such as product innovation, partnering, or spinout creation, place the company where the flow of opportunities is greatest. Simple rules then provide the guidelines within which managers can pursue such opportunities. Simple rules, which grow out of experience, fall into five broad categories: how- to rules, boundary conditions, priority rules, timing rules, and exit rules. Companies with simple-rules strategies must follow the rules religiously and avoid the temptation to change them too frequently. A consistent strategy helps managers sort through opportunities and gain short-term advantage by exploiting the attractive ones. In stable markets, managers rely on complicated strategies built on detailed predictions of the future. But when business is complicated, strategy should be simple.

  2. Pd-Catalyzed Heterocycle Synthesis in Ionic Liquids

    NASA Astrophysics Data System (ADS)

    Li, Jianxiao; Jiang, Huanfeng

    Heterocyclic and fused heterocyclic compounds are ubiquitously found in natural products and biologically interesting molecules, and many currently marketed drugs hold heterocycles as their core structure. In this chapter, recent advances on Pd-catalyzed synthesis of heterocycles in ionic liquids (ILs) are reviewed. In palladium catalysis, ILs with different cations and anions are investigated as an alternative recyclable and environmentally benign reaction medium, and a variety of heterocyclic compounds including cyclic ketals, quinolones, quinolinones, isoindolinones, and lactones are conveniently constructed. Compared to the traditional methods, these new approaches have many advantages, such as environmentally friendly synthetic procedure, easy product and catalyst separation, recyclable medium, which make them have the potential applications in industry.

  3. Triazolium-based Energetic Ionic Liquids

    DTIC Science & Technology

    2005-03-01

    for public release; distribution unlimited. 18 References 1. Ionic Liquids, Industrial Applications to Green Chemistry ACS Symposium Series 818...Chem. Soc. 126, 11788-11789(2004). 11. Wilkes, J. S. in Ionic Liquids, Industrial Applications to Green Chemistry , ACS Symposium Series 818, R

  4. Chemical and Electrochemical Studies in Ionic Liquids

    DTIC Science & Technology

    1990-01-12

    Electrochemistry and Witchcraft ", Gordon Research Conference on Electrochemistry", Santa Barbara, CA, January, 1985. OR. A. Osteryoung, ’An Introduction to...Temperature Chloroaluminate Ionic Liquids: Chemistry, Electrochemistry and Witchcraft ", Chemistry Department Colloquium, University of Alabama...Tuscaloosa, Alabama, December 1, 1988. OR. A. Osteryoung, "Ambient Temperature Chloroaluminate Ionic Liquids: Chemistry, Electrochemistry and Witchcraft

  5. Hierarchical cooperative binary ionic porphyrin nanocomposites.

    PubMed

    Tian, Yongming; Busani, Tito; Uyeda, Gregory H; Martin, Kathleen E; van Swol, Frank; Medforth, Craig J; Montaño, Gabriel A; Shelnutt, John A

    2012-05-18

    Cooperative binary ionic (CBI) solids comprise a versatile new class of opto-electronic and catalytic materials consisting of ionically self-assembled pairs of organic anions and cations. Herein, we report CBI nanocomposites formed by growing nanoparticles of one type of porphyrin CBI solid onto a second porphyrin CBI substructure with complementary functionality.

  6. Engineered microorganisms having resistance to ionic liquids

    SciTech Connect

    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.

  7. Ionic liquid-in-oil microemulsions.

    PubMed

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

    2005-05-25

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

  8. Synthesis and properties of polymerized ionic liquids

    DOE PAGES

    Eftekhari, Ali; Saito, Tomonori

    2017-03-14

    Polymerization of ionic liquids results in the formation of ionic polymers, which are called poly (ionic liquid)s or polymerized ionic liquids (PIL). This is a brand new form of ionicity in polymer chains with a broad range of applications, though ionic polymers have a long history with the sub-families of polyelectrolytes and ionomers. Although mobility of ions in ionic liquids has named them as the promising candidates for various applications, their applicability is limited in many practical systems because of not having the advantages of neither liquids nor solids, suffering from both leakage issue and high viscosity. PILs perfectly fitmore » with the practical requirements while having almost all features of ionic liquids. This review summarizes some potential applications of PILs. The architecture of PILs can be easily re-designed by both the polymer backbone and outer ion. Not only by post-polymerization but also by in situ ion exchange, the chemical and mechanical properties of PILs can be tuned. Lastly, owing to the high chemical activity and flexible architecture, PILs are the promising candidates for sensors and actuators, electroactive binders, solid and gel electrolytes, non-blocking matrix of nanocomposites, etc.« less

  9. Depolarization of water in protic ionic liquids.

    PubMed

    Zahn, Stefan; Wendler, Katharina; Delle Site, Luigi; Kirchner, Barbara

    2011-09-07

    A mixture of the protic ionic liquid mono-methylammonium nitrate with 1.6 wt% water was investigated from Car-Parrinello molecular dynamics simulations. In contrast to imidazolium-based ionic liquids, the cation possesses strong directional hydrogen bonds to water and all hydrogen bonds in the mixture have a comparable strength. This results in a good incorporation of water into the hydrogen bond network of mono-methylammonium nitrate and a tetrahedral hydrogen bond coordination of water. Hence, one might expect a larger dipole moment of water in the investigated mixture compared to neat water due to the good hydrogen bond network incorporation and the charged vicinity of water in the protic ionic liquid. However, the opposite is observed pointing to strong electrostatic screening in protic ionic liquids. Additionally, the influence of water on the properties of the protic ionic liquid is discussed.

  10. Lithium-Air and ionic Liquids

    SciTech Connect

    Kellar, Michael

    2015-09-01

    The final portion of this project was accomplished at Sandia National Labs, Livermore, with the overall goal being to optimize lithium-air cells with an ionic liquid electrolyte. Both of these are potential future routes for lithium-ion technology. Lithiumair presents the advantage of higher gravimetric energy density, and ionic liquids present the advantage of greater hydrophobicity and much lower volatility, along with a larger window of electrochemical stability. Ionic liquids however have several drawbacks for the battery industry. Currently they are not as cost effective as many organic solvents. Additionally, because of the added viscosity of ionic interactions compared to the typical dipole interactions of a solvent, the ionic conductivity is lower than for common organic solvents.

  11. Solid State Ionics Advanced Materials for Emerging Technologies

    NASA Astrophysics Data System (ADS)

    Chowdari, B. V. R.; Careem, M. A.; Dissanayake, M. A. K. L.; Rajapakse, R. M. G.; Seneviratne, V. A.

    2006-06-01

    spectroscopic analysis of thin film LiNiVO[symbol] prepared by pulsed laser deposition technique / S. Selvasekarapandian ... [et al.]. Synthesis and characterization of LiFePO[symbol] cathode materials by microwave processing / J. Zhou ... [et al.]. Characterization of Nd[symbol]Sr[symbol]CoO[symbol] including Pt second phase as the cathode material for low-temperature SOFCs / J. W. Choi ... [et al.]. Thermodynamic behavior of lithium intercalation into natural vein and synthetic graphite / N. W. B. Balasooriya, P. W. S. K. Bandaranayake, Ph. Touzain -- pt. III. Electroactive polymers. Invited papers. Organised or disorganised? looking at polymer electrolytes from both points of view / Y.-P. Liao ... [et al.]. Polymer electrolytes - simple low permittivity solutions? / I. Albinsson, B.-E. Mellander. Dependence of conductivity enhancement on the dielectric constant of the dispersoid in polymer-ferroelectric composite electrolytes / A. Chandra, P. K. Singh, S. Chandra. Design and application of boron compounds for high-performance polymer electrolytes / T. Fujinami. Structural, vibrational and AC impedance analysis of nano composite polymer electrolytes based on PVAC / S. Selvasekarapandian ... [et al.]. Absorption intensity variation with ion association in PEO based electrolytes / J. E. Furneaux ... [et al.]. Study of ion-polymer interactions in cationic and anionic ionomers from the dependence of conductivity on pressure and temperature / M. Duclot ... [et al.]. Triol based polyurethane gel electrolytes for electrochemical devices / A. R. Kulkarni. Contributed papers. Accurate conductivity measurements to solvation energies in nafion / M. Maréchal, J.-L Souquet. Ion conducting behaviour of composite polymer gel electrolyte: PEG-PVA-(NH[symbol]CH[symbol]CO[symbol])[symbol] system / S. L. Agrawal, A. Awadhia, S. K. Patel. Impedance spectroscopy and DSC studies of poly(vinylalcohol)/ silicotungstic acid crosslinked composite membranes / A. Anis, A. K. Banthia. (PEO

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

    SciTech Connect

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

    2015-02-20

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

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

    DOE PAGES

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

    2015-02-20

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

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

    PubMed Central

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

    2015-01-01

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

  15. Ionic homeostasis in brain conditioning

    PubMed Central

    Cuomo, Ornella; Vinciguerra, Antonio; Cerullo, Pierpaolo; Anzilotti, Serenella; Brancaccio, Paola; Bilo, Leonilda; Scorziello, Antonella; Molinaro, Pasquale; Di Renzo, Gianfranco; Pignataro, Giuseppe

    2015-01-01

    Most of the current focus on developing neuroprotective therapies is aimed at preventing neuronal death. However, these approaches have not been successful despite many years of clinical trials mainly because the numerous side effects observed in humans and absent in animals used at preclinical level. Recently, the research in this field aims to overcome this problem by developing strategies which induce, mimic, or boost endogenous protective responses and thus do not interfere with physiological neurotransmission. Preconditioning is a protective strategy in which a subliminal stimulus is applied before a subsequent harmful stimulus, thus inducing a state of tolerance in which the injury inflicted by the challenge is mitigated. Tolerance may be observed in ischemia, seizure, and infection. Since it requires protein synthesis, it confers delayed and temporary neuroprotection, taking hours to develop, with a pick at 1–3 days. A new promising approach for neuroprotection derives from post-conditioning, in which neuroprotection is achieved by a modified reperfusion subsequent to a prolonged ischemic episode. Many pathways have been proposed as plausible mechanisms to explain the neuroprotection offered by preconditioning and post-conditioning. Although the mechanisms through which these two endogenous protective strategies exert their effects are not yet fully understood, recent evidence highlights that the maintenance of ionic homeostasis plays a key role in propagating these neuroprotective phenomena. The present article will review the role of protein transporters and ionic channels involved in the control of ionic homeostasis in the neuroprotective effect of ischemic preconditioning and post-conditioning in adult brain, with particular regards to the Na+/Ca2+ exchangers (NCX), the plasma membrane Ca2+-ATPase (PMCA), the Na+/H+ exchange (NHE), the Na+/K+/2Cl− cotransport (NKCC) and the acid-sensing cation channels (ASIC). Ischemic stroke is the third leading

  16. X-ray Photoelectron Spectroscopy of Pyridinium-Based Ionic Liquids: Comparison to Imidazolium- and Pyrrolidinium-Based Analogues.

    PubMed

    Men, Shuang; Mitchell, Daniel S; Lovelock, Kevin R J; Licence, Peter

    2015-07-20

    We investigate eight 1-alkylpyridinium-based ionic liquids of the form [Cn Py][A] by using X-ray photoelectron spectroscopy (XPS). The electronic environment of each element of the ionic liquids is analyzed. In particular, a reliable fitting model is developed for the C 1s region that applies to each of the ionic liquids. This model allows the accurate charge correction of binding energies and the determination of reliable and reproducible binding energies for each ionic liquid. Shake-up/off phenomena are determinedfor both C 1s and N 1s spectra. The electronic interaction between cations and anions is investigated for both simple ionic liquids and an example of an ionic-liquid mixture; the effect of the anion on the electronic environment of the cation is also explored. Throughout the study, a detailed comparison is made between [C8 Py][A] and analogues including 1-octyl-1-methylpyrrolidinium- ([C8 C1 Pyrr][A]), and 1-octyl-3-methylimidazolium- ([C8 C1 Im][A]) based samples, where X is common to all ionic liquids.

  17. Aquivalence revisited--new model formulation and application to assess environmental fate of ionic pharmaceuticals in Hamilton Harbour, Lake Ontario.

    PubMed

    Csiszar, Susan A; Gandhi, Nilima; Alexy, Radka; Benny, Donald T; Struger, John; Marvin, Chris; Diamond, Miriam L

    2011-07-01

    A model formulation based on "aquivalence", as defined in terms of activity is presented to estimate the multimedia fate of ionizing chemicals. The aquivalence approach is analogous to fugacity but aquivalence is applicable to neutral and ionizing compounds, and has been applied previously to speciating chemicals, notably metals. The new aquivalence-based mass-balance model treats ionizing organic compounds that exist as interconverting neutral and ionic species which are subject to fate processes at differing rates. The model is illustrated by application to four ionizing pharmaceuticals in Hamilton Harbour, Lake Ontario. At the system pH of 7.9-8.5, ibuprofen, gemfibrozil, and naproxen are expected to be almost entirely ionic and triclosan split between ionic and neutral forms. Measured seasonal surface water concentrations, which were 2-10 times lower in the late summer and fall than during spring, were used to solve for unknown values of chemical half-life in the water column due to degradation (photo- and bio-) of the ionizing and neutral forms and secondarily, ionic sorption coefficients of the ionizing forms. Model estimates of half-lives in the habour's water ranged from 11 to 77, 11 to 147 and 10 to 37 for ionic ibuprofen, gemfibrozil, and naproxen, respectively; and 4-22 days and 2-9 days for ionic and neutral triclosan, respectively, with the shortest half-lives in spring and the longest in summer.

  18. Multipurpose Compound

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Specially formulated derivatives of an unusual basic compound known as Alcide may be the answer to effective treatment and prevention of the disease bovine mastitis, a bacterial inflammation of a cow's mammary gland that results in loss of milk production and in extreme cases, death. Manufactured by Alcide Corporation the Alcide compound has killed all tested bacteria, virus and fungi, shortly after contact, with minimal toxic effects on humans or animals. Alcide Corporation credits the existence of the mastitis treatment/prevention products to assistance provided the company by NERAC, Inc.

  19. Amphiphile Meets Amphiphile: Beyond the Polar-Apolar Dualism in Ionic Liquid/Alcohol Mixtures.

    PubMed

    Russina, Olga; Sferrazza, Alessio; Caminiti, Ruggero; Triolo, Alessandro

    2014-05-15

    The mesoscopic morphology of binary mixtures of ethylammonium nitrate (EAN), the protic ionic liquid par excellence, and methanol is explored using neutron/X-ray diffraction and computational techniques. Both compounds are amphiphilic and characterized by an extended hydrogen bonding network: surprisingly, though macroscopically homogeneous, these mixtures turn out to be mesoscopically highly heterogeneous. Our study reveals that even in methanol-rich mixtures, a wide distribution of clusters exists where EAN preserves its bulk, sponge-like morphology. Accordingly methanol does not succeed in fully dissociating the ionic liquid that keeps on organizing in a bulk-like fashion. This behavior represents the premises to the more dramatic phenomenology observed with longer alcohols that eventually phase separate from EAN. These results challenge the commonly accepted polar and apolar moieties segregation in ionic liquids/molecular liquids mixtures and the current understanding of technologically relevant solvation processes.

  20. A brief overview of the potential environmental hazards of ionic liquids.

    PubMed

    Bubalo, Marina Cvjetko; Radošević, Kristina; Redovniković, Ivana Radojčić; Halambek, Jasna; Srček, Višnja Gaurina

    2014-01-01

    Over past decades ionic liquids, a promising alternative to traditional organic solvents, have been dramatically expanding in popularity as a new generation of chemicals with potential uses in various areas in industry. In the literature these compounds have often been referred to as environmentally friendly; however, in recent years the perception of their greenness dramatically changed as the scientific community began to proactively assess the risk of their application based on the entire life-cycle. This review gives a brief overview of the current knowledge regarding the potential risks linked to the application of ionic liquids - from preparation to their disposal, with special emphasis on their potential environmental impacts and future directions in designing inherently safer ionic liquids.

  1. Origin of the Formulas of Dihydrogen and Other Simple Molecules

    ERIC Educational Resources Information Center

    Williams, Andrew

    2007-01-01

    The logic and experimental data are described with which chemists originally deduced the formulas of the fundamental compounds such as H[subscript 2], H[subscript 2]O, Cl[subscript 2], NH[subscript 3], CH[subscript 4], and HCl. This information is never provided in current texts at any level and the formulas of such simple compounds are taken as…

  2. Three dimensionally honeycomb layered double hydroxides framework as a novel fiber coating for headspace solid-phase microextraction of phenolic compounds.

    PubMed

    Abolghasemi, Mir Mahdi; Yousefi, Vahid

    2014-06-06

    A new solid phase microextraction (SPME) fiber based on high-temperature three dimensionally honeycomb layered double hydroxide (TDH-LDH) material is presented. The fiber coating can be prepared easily, it is mechanically stable and exhibits relatively high thermal stability. This study shows that three dimensionally honeycomb layered double hydroxide generated porous morphology. The TDH-LDH material was tested for the extraction of some phenolic and polycyclic aromatic hydrocarbon compounds from aqueous sample solutions in combination with gas chromatography-mass spectrometry (GC-MS). The TDH-LDH fiber contains polar groups and its efficiency for non-polar polycyclic aromatic hydrocarbon compounds was lower than phenolic compounds. On the other hand, a high tendency towards the adsorption of polar phenolic compounds was observed for the proposed fiber. The effects of the extraction and desorption parameters including extraction temperature, extraction time, ionic strength, stirring rate, pH and desorption temperature and time have been studied. In optimum conditions, the repeatability for one fiber (n=5), expressed as relative standard deviation (R.S.D. %), was between 2.8% and 7.1% for the phenolic compounds. The detection limits for the studied phenolic compounds were between 0.02 and 5.8 ng mL(-1). The developed method offers the advantage of being simple to use, with shorter analysis time, lower cost of equipment, thermal stability of fiber and high relative recovery in comparison to conventional methods of analysis.

  3. Infrared spectroscopy of ionic clusters

    SciTech Connect

    Price, J.M. . Dept. of Chemistry Lawrence Berkeley Lab., CA )

    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.

  4. Interdiffusion in binary ionic mixtures

    SciTech Connect

    Boercker, D.B.; Pollock, E.L.

    1987-08-15

    In this paper we present molecular-dynamics and kinetic-theory calculations of the interdiffusion coefficients in dense binary ionic mixtures for conditions appropriate to both astrophysical and inertial-confinement fusion (ICF) plasmas. The diffusion coefficient is the product of a Green-Kubo integral and a thermodynamic prefactor. The molecular-dynamics and kinetic-theory estimates of the Green-Kubo portion agree very well, and it is found that this integral may also be well represented by the usual concentration-weighted sum of self-diffusion coefficients. In addition, the low-density limit of the thermodynamic prefactor is shown to represent an enhancement of the diffusion by the ''ambipolar'' electric field.

  5. A Simple Wave Driver

    ERIC Educational Resources Information Center

    Temiz, Burak Kagan; Yavuz, Ahmet

    2015-01-01

    This study was done to develop a simple and inexpensive wave driver that can be used in experiments on string waves. The wave driver was made using a battery-operated toy car, and the apparatus can be used to produce string waves at a fixed frequency. The working principle of the apparatus is as follows: shortly after the car is turned on, the…

  6. Simple Magnetometer for Autopilots

    NASA Technical Reports Server (NTRS)

    Garner, H. D.

    1982-01-01

    Simple, low-cost magnetometer is suitable for heading-reference applications in autopilots and other directional control systems. Sensing element utilizes commercially available transformer core; and supporting electronics consist of one transistor, two readily-available integrated-circuit chips, and associated resistors and capacitors.

  7. A Simple Tiltmeter

    NASA Technical Reports Server (NTRS)

    Dix, M. G.; Harrison, D. R.; Edwards, T. M.

    1982-01-01

    Bubble vial with external aluminum-foil electrodes is sensing element for simple indicating tiltmeter. To measure bubble displacement, bridge circuit detects difference in capacitance between two sensing electrodes and reference electrode. Tiltmeter was developed for experiment on forecasting seismic events by changes in Earth's magnetic field.

  8. Working with Simple Machines

    ERIC Educational Resources Information Center

    Norbury, John W.

    2006-01-01

    A set of examples is provided that illustrate the use of work as applied to simple machines. The ramp, pulley, lever and hydraulic press are common experiences in the life of a student, and their theoretical analysis therefore makes the abstract concept of work more real. The mechanical advantage of each of these systems is also discussed so that…

  9. Entropy Is Simple, Qualitatively.

    ERIC Educational Resources Information Center

    Lambert, Frank L.

    2002-01-01

    Suggests that qualitatively, entropy is simple. Entropy increase from a macro viewpoint is a measure of the dispersal of energy from localized to spread out at a temperature T. Fundamentally based on statistical and quantum mechanics, this approach is superior to the non-fundamental "disorder" as a descriptor of entropy change. (MM)

  10. Climate Change Made Simple

    ERIC Educational Resources Information Center

    Shallcross, Dudley E.; Harrison, Tim G.

    2007-01-01

    The newly revised specifications for GCSE science involve greater consideration of climate change. This topic appears in either the chemistry or biology section, depending on the examination board, and is a good example of "How Science Works." It is therefore timely that students are given an opportunity to conduct some simple climate modelling.…

  11. On Simple Science.

    ERIC Educational Resources Information Center

    Cole, K.C.

    1982-01-01

    Discusses San Francisco's Exploratorium, a science teaching center with 500 exhibits focusing on human perception, but extending to everything from the mechanics of voice to the art of illusion, from holograms to harmonics. The Exploratorium emphasizes "simple science" (refractions/resonances, sounds/shadows) to tune in the senses and turn on the…

  12. Simple Lookup Service

    SciTech Connect

    2013-05-01

    Simple Lookup Service (sLS) is a REST/JSON based lookup service that allows users to publish information in the form of key-value pairs and search for the published information. The lookup service supports both pull and push model. This software can be used to create a distributed architecture/cloud.

  13. A Simple Hydrogen Electrode

    ERIC Educational Resources Information Center

    Eggen, Per-Odd

    2009-01-01

    This article describes the construction of an inexpensive, robust, and simple hydrogen electrode, as well as the use of this electrode to measure "standard" potentials. In the experiment described here the students can measure the reduction potentials of metal-metal ion pairs directly, without using a secondary reference electrode. Measurements…

  14. Influence of the ionic liquid/gas surface on ionic liquid chemistry.

    PubMed

    Lovelock, Kevin R J

    2012-04-21

    Applications such as gas storage, gas separation, NP synthesis and supported ionic liquid phase catalysis depend upon the interaction of different species with the ionic liquid/gas surface. Consequently, these applications cannot proceed to the full extent of their potential without a profound understanding of the surface structure and properties. As a whole, this perspective contains more questions than answers, which demonstrates the current state of the field. Throughout this perspective, crucial questions are posed and a roadmap is proposed to answer these questions. A critical analysis is made of the field of ionic liquid/gas surface structure and properties, and a number of design rules are mined. The effects of ionic additives on the ionic liquid/gas surface structure are presented. A possible driving force for surface formation is discussed that has, to the best of my knowledge, not been postulated in the literature to date. This driving force suggests that for systems composed solely of ions, the rules for surface formation of dilute electrolytes do not apply. The interaction of neutral additives with the ionic liquid/gas surface is discussed. Particular attention is focussed upon H(2)O and CO(2), vital additives for many applications of ionic liquids. Correlations between ionic liquid/gas surface structure and properties, ionic liquid surfaces plus additives, and ionic liquid applications are given.

  15. Perfluorinated Compounds

    EPA Science Inventory

    Perfluorinated compounds such as the perfluoroalkyl acids (PFAAs) and their derivatives are important man-made chemicals that have wide consumer and industrial applications. They are relatively contemporary chemicals, being in use only since the 1950s, and until recently, have be...

  16. Electric double layer at the interface of ionic liquid-dielectric liquid under electric field.

    PubMed

    Lee, D W; Im, D J; Kang, I S

    2013-02-12

    The structure of the electric double layer (EDL) is analyzed in order to understand the electromechanical behavior of the interface of ionic liquid-dielectric liquid. The modified Poisson-Boltzmann equation proposed by Bazant et al. is solved to see the crowding and the overscreening effects that are the characteristics of an ionic liquid (Bazant, M. Z.; Storey, B. D.; Kornyshev, A. A. Double layer in ionic liquids: Overscreening versus crowding. Phys. Rev. Lett. 2011, 106, 046102.). From the simple one-dimensional (1-D) analysis, it is found that the changes of the composition and the material properties in the EDL are negligible except under some extreme conditions such as strong electric field over O(10(8)) V/m. From the electromechanical view points, an ionic liquid behaves like a pure conductor at the interface with a dielectric liquid. Based on these findings, three specific application problems are considered. In the first, a new method is suggested for measuring the interfacial tension of an ionic liquid-dielectric liquid system. The deformation of a charged ionic liquid droplet translating between two electrodes is used for this measurement. The second is for the Taylor cone problem, which includes an extreme electric field condition near the tip. The size of the critical region, where the EDL effect should be considered, is estimated by using the 1-D analysis result. Numerical computation is also performed to see the profiles of electric potential and the electric stress along the interface of the Taylor cone. Lastly, the electrowetting problem of the ionic liquid is considered. The discrepancies in the results of previous workers are interpreted by using the results of the present work. It is shown that all the results might be consistent if the leaking of the dielectric layer and/or the adsorption of ions is considered.

  17. Ionic liquids for rechargeable lithium batteries

    SciTech Connect

    Salminen, Justin; Papaiconomou, Nicolas; Kerr, John; Prausnitz,John; Newman, John

    2005-09-29

    We have investigated possible anticipated advantages of ionic-liquid electrolytes for use in lithium-ion batteries. Thermal stabilities and phase behavior were studied by thermal gravimetric analysis and differential scanning calorimetry. The ionic liquids studied include various imidazoliumTFSI systems, pyrrolidiniumTFSI, BMIMPF{sub 6}, BMIMBF{sub 4}, and BMIMTf. Thermal stabilities were measured for neat ionic liquids and for BMIMBF{sub 4}-LiBF{sub 4}, BMIMTf-LiTf, BMIMTFSI-LiTFSI mixtures. Conductivities have been measured for various ionic-liquid lithium-salt systems. We show the development of interfacial impedance in a Li|BMIMBF{sub 4} + LiBF{sub 4}|Li cell and we report results from cycling experiments for a Li|BMIMBF{sub 4} + 1 mol/kg LIBF{sub 4}|C cell. The interfacial resistance increases with time and the ionic liquid reacts with the lithium electrode. As expected, imidazolium-based ionic liquids react with lithium electrodes. We seek new ionic liquids that have better chemical stabilities.

  18. The influence of ionic forces on the effective diffusion coefficient in fractured, porous chalk.

    NASA Astrophysics Data System (ADS)

    Kremer, K.; Reichert, B.

    2005-12-01

    Solute transport in fractured, highly porous chalk significantly depends on the diffusive mass transfer of substances between the mobile water in the fracture and the immobile water of the rock matrix. Matrix diffusion is an important transport mechanism and a central factor for the retardation of solutes. Until now, simple estimation methods for the diffusive behavior of substances such as Archie's law can only be applied to single substances. Multi-tracer experiments proved a mutual influence on the diffusion of ionic solutes thus leading to significant deviations in respect to the theoretically estimated effective diffusion coefficient D_e. An increase of ionic forces in the aqueous phase is often accompanied by a decrease of D_e for cations and an increase for anions. However, groundwater contamination usually consists of several pollutants in different mixtures. Besides ionic forces, effects of channeling and transport of colloids can result in incorrectly estimated D_e values and, hence, high inaccuracy in the modeling of contaminant transport in fractured porous media. In the context of a current DFG-project, the impact of ionic forces on D_e as well as the interaction of the diffusion of ionic ground water solutes in fractured chalk of Denmark (Cretaceous, Sigerslev) and Israel (Eocene, Negev desert) will be quantified to develop a procedure for an improved estimation of D_e in dependence of the ionic activity. Consequently, the well established Archie's law for the prediction of diffusivities on the basis of the total porosities will be modified by an extension term a. So far series of single-tracer through-diffusion experiments have been performed with potassium bromide in six different concentrations to quantify the concentration dependence on the matrix diffusion as well as to examine the influence of the ionic strength on the effective diffusion coefficients of ionic solutes. The simultaneously injected neutral deuterium serves as a reference tracer

  19. Electric-double-layer field-effect transistors with ionic liquids.

    PubMed

    Fujimoto, Takuya; Awaga, Kunio

    2013-06-21

    Charge carrier control is a key issue in the development of electronic functions of semiconductive materials. Beyond the simple enhancement of conductivity, high charge carrier accumulation can realize various phenomena, such as chemical reaction, phase transition, magnetic ordering, and superconductivity. Electric double layers (EDLs), formed at solid-electrolyte interfaces, induce extremely large electric fields. This results in a high charge carrier accumulation in the solid, much more effectively than solid dielectric materials. In the present review, we describe recent developments in the field-effect transistors (FETs) with gate dielectrics of ionic liquids, which have attracted much attention due to their wide electrochemical windows, low vapor pressures, and high chemical and physical stability. We explain the capacitance effects of ionic liquids, and describe the various combinations of ionic liquids and organic and inorganic semiconductors that are used to achieve such effects as high transistor performance, insulator-metal transitions, superconductivity, and ferromagnetism, in addition to the applications of the ionic-liquid EDL-FETs in logic devices. We discuss the factors controlling the mobility and threshold voltage in these types of FETs, and show the ionic liquid dependence of the transistor performance.

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

    PubMed

    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.

  1. Development of Novel, Simple Multianalyte Sensors for Remote Environmental Analysis

    SciTech Connect

    Professor Sanford A. Asher

    2003-02-18

    Advancement of our polymerized crystalline colloidal array chemical sensing technology. They have dramatically advanced their polymerized crystalline colloidal array chemical sensing technology. They fabricated nonselective sensors for determining pH and ionic strength. They also developed selective sensors for glucose and organophosphorus mimics of nerve gas agents. They developed a trace sensor for cations in water which utilized a novel crosslinking sensing motif. In all of these cases they have been able to theoretically model their sensor response by extending hydrogel volume phase transition theory. They also developed transient sampling methods to allow their ion sensing methods to operate at high ionic strengths. They also developed a novel optrode to provide for simple sampling.

  2. MOLECULAR BASIS OF BIODEGRADATION OF CHLOROAROMATIC COMPOUNDS

    EPA Science Inventory

    Chlorinated aromatic hydrocarbons are widely used in industry and agriculture, and comprise the bulk of environmental pollutants. Although simple aromatic compounds are biodegradable by a variety of degradative pathways, their halogenated counterparts are more resistant to bacter...

  3. Design and Evaluation of Ionic Liquids as Novel CO2 Absorbents

    SciTech Connect

    Edward J. Maginn

    2006-09-30

    Progress from the third quarter 2006 activity on the project ''Design and Evaluation of Ionic Liquids as Novel CO{sub 2} Absorbents'' is provided. Major activities in two areas are reported: property measurement and molecular modeling. We have measured CO{sub 2} solubility in an ammonium lactate ionic liquid. Previous work has shown that the lactate anion enables chemical complexation to occur. We hypothesized that the lactate anion would not be as effective in complexing when paired with an ammonium cation as compared to when it is paired with an imidazolium cation. The results confirm this. We also measured CO{sub 2} solubility in a functionalized ionic liquid containing an amine group. These so-called task specific ionic liquids (TSILs) are expected to have dramatically higher CO{sub 2} solubility than physical absorbents. We report isotherms as well as entropies and enthalpies of absorption for CO{sub 2} in one TSIL. CO{sub 2} solubilities are higher in this compound than in any previous IL we have observed. Finally, we also developed a new simulation method that will enable us to compute full isotherms of gases in ionic liquids. So far, we have tested the method against model systems and found it to be highly effective.

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

    PubMed

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

    2015-03-15

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

  5. Vaporisation of a dicationic ionic liquid revisited.

    PubMed

    Vitorino, Joana; Leal, João P; Licence, Peter; Lovelock, Kevin R J; Gooden, Peter N; Minas da Piedade, Manuel E; Shimizu, Karina; Rebelo, Luís P N; Canongia Lopes, José N

    2010-12-03

    The vaporization of a dicationic ionic liquid at moderate temperatures and under reduced pressures--recently studied by line-of-sight mass spectrometry--was further analyzed using an ion-cyclotron resonance mass spectroscopy technique that allows the monitoring of the different species present in the gas phase through the implementation of controlled ion-molecule reactions. The results support the view that the vapour phase of an aprotic dicationic ionic liquid is composed of neutral ion triplets (one dication attached to two anions). Molecular dynamics simulations were also performed in order to explain the magnitude of the vaporization enthalpies of dicationic ionic liquids vis-à-vis their monocationic counterparts.

  6. Quantized friction across ionic liquid thin films

    NASA Astrophysics Data System (ADS)

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

    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.

  7. Quantized friction across ionic liquid thin films.

    PubMed

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

    2013-10-07

    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.

  8. Ion pairing and phase behaviour of an asymmetric restricted primitive model of ionic liquids

    NASA Astrophysics Data System (ADS)

    Lu, Hongduo; Li, Bin; Nordholm, Sture; Woodward, Clifford E.; Forsman, Jan

    2016-12-01

    An asymmetric restricted primitive model (ARPM) of electrolytes is proposed as a simple three parameter (charge q, diameter d, and charge displacement b) model of ionic liquids and solutions. Charge displacement allows electrostatic and steric interactions to operate between different centres, so that orientational correlations arise in ion-ion interactions. In this way the ionic system may have partly the character of a simple ionic fluid/solid and of a polar fluid formed from ion pairs. The present exploration of the system focuses on the ion pair formation mechanism, the relative concentration of paired and free ions and the consequences for the cohesive energy, and the tendency to form fluid or solid phase. In contrast to studies of similar (though not identical) models in the past, we focus on behaviours at room temperature. By MC and MD simulations of such systems composed of monovalent ions of hard-sphere (or essentially hard-sphere) diameter equal to 5 Å and a charge displacement ranging from 0 to 2 Å from the hard-sphere origin, we find that ion pairing dominates for b larger than 1 Å. When b exceeds about 1.5 Å, the system is essentially a liquid of dipolar ion pairs with a small presence of free ions. We also investigate dielectric behaviours of corresponding liquids, composed of purely dipolar species. Many basic features of ionic liquids appear to be remarkably consistent with those of our ARPM at ambient conditions, when b is around 1 Å. However, the rate of self-diffusion and, to a lesser extent, conductivity is overestimated, presumably due to the simple spherical shape of our ions in the ARPM. The relative simplicity of our ARPM in relation to the rich variety of new mechanisms and properties it introduces, and to the numerical simplicity of its exploration by theory or simulation, makes it an essential step on the way towards representation of the full complexity of ionic liquids.

  9. Mesophase stabilization in ionic liquid crystals through pairing equally shaped mesogenic cations and anions

    SciTech Connect

    Stappert, Kathrin; Lipinski, Gregor; Kopiec, Gabriel; Spielberg, Eike T.; Mudring, Anja -Verena

    2015-07-23

    The synthesis and properties of a set of novel ionic liquid crystals with congruently shaped cations and anions are reported to check whether pairing mesogenic cations with mesogenic anions leads to a stabilization of a liquid crystalline phase. To that avail 1-alkyl-3-methyl-triazolium cations with an alkyl chain length of 10, 12, and 14 carbon atoms have been combined with p-alkyloxy-benzenesulfonate anions with different alkyl chain lengths (n = 10, 12, and 14). The corresponding triazolium iodides have been synthesized as reference compounds where the cation and anion have strong size and shape mismatch. The mesomorphic behavior of all compounds is studied by differential scanning calorimetry and polarizing optical microscopy. All compounds except 1-methyl-3-decyltriazolium iodide, which qualifies as an ionic liquid, are thermotropic ionic liquid crystals. All other compounds adopt smectic A phases. As a result, a comparison of the thermal phase behavior of the 1-methyl-3-decyltriazolium bromides to the corresponding p-alkoxy-benzensulfonates reveals that definitely the mesophase is stabilized by pairing the rod-shaped 1-alkyl-3-methyltriazolium cation with a rod-like anion of similar size.

  10. Mesophase stabilization in ionic liquid crystals through pairing equally shaped mesogenic cations and anions

    DOE PAGES

    Stappert, Kathrin; Lipinski, Gregor; Kopiec, Gabriel; ...

    2015-07-23

    The synthesis and properties of a set of novel ionic liquid crystals with congruently shaped cations and anions are reported to check whether pairing mesogenic cations with mesogenic anions leads to a stabilization of a liquid crystalline phase. To that avail 1-alkyl-3-methyl-triazolium cations with an alkyl chain length of 10, 12, and 14 carbon atoms have been combined with p-alkyloxy-benzenesulfonate anions with different alkyl chain lengths (n = 10, 12, and 14). The corresponding triazolium iodides have been synthesized as reference compounds where the cation and anion have strong size and shape mismatch. The mesomorphic behavior of all compounds ismore » studied by differential scanning calorimetry and polarizing optical microscopy. All compounds except 1-methyl-3-decyltriazolium iodide, which qualifies as an ionic liquid, are thermotropic ionic liquid crystals. All other compounds adopt smectic A phases. As a result, a comparison of the thermal phase behavior of the 1-methyl-3-decyltriazolium bromides to the corresponding p-alkoxy-benzensulfonates reveals that definitely the mesophase is stabilized by pairing the rod-shaped 1-alkyl-3-methyltriazolium cation with a rod-like anion of similar size.« less

  11. Simple Waveforms, Simply Described

    NASA Technical Reports Server (NTRS)

    Baker, John G.

    2008-01-01

    Since the first Lazarus Project calculations, it has been frequently noted that binary black hole merger waveforms are 'simple.' In this talk we examine some of the simple features of coalescence and merger waveforms from a variety of binary configurations. We suggest an interpretation of the waveforms in terms of an implicit rotating source. This allows a coherent description, of both the inspiral waveforms, derivable from post-Newtonian(PN) calculations, and the numerically determined merger-ringdown. We focus particularly on similarities in the features of various Multipolar waveform components Generated by various systems. The late-time phase evolution of most L these waveform components are accurately described with a sinple analytic fit. We also discuss apparent relationships among phase and amplitude evolution. Taken together with PN information, the features we describe can provide an approximate analytic description full coalescence wavefoRms. complementary to other analytic waveforns approaches.

  12. Simple Schlieren Light Meter

    NASA Technical Reports Server (NTRS)

    Rhodes, David B.; Franke, John M.; Jones, Stephen B.; Leighty, Bradley D.

    1992-01-01

    Simple light-meter circuit used to position knife edge of schlieren optical system to block exactly half light. Enables operator to check quickly position of knife edge between tunnel runs to ascertain whether or not in alignment. Permanent measuring system made part of each schlieren system. If placed in unused area of image plane, or in monitoring beam from mirror knife edge, provides real-time assessment of alignment of schlieren system.

  13. Simple Finite Jordan Pseudoalgebras

    NASA Astrophysics Data System (ADS)

    Kolesnikov, Pavel

    2009-01-01

    We consider the structure of Jordan H-pseudoalgebras which are linearly finitely generated over a Hopf algebra H. There are two cases under consideration: H = U(h) and H = U(h) # C[Γ], where h is a finite-dimensional Lie algebra over C, Γ is an arbitrary group acting on U(h) by automorphisms. We construct an analogue of the Tits-Kantor-Koecher construction for finite Jordan pseudoalgebras and describe all simple ones.

  14. Using FT-IR spectroscopy to measure charge organization in ionic liquids.

    PubMed

    Burba, Christopher M; Janzen, Jonathan; Butson, Eric D; Coltrain, Gage L

    2013-07-25

    A major goal in the field of ionic liquids is correlating transport property trends with the underlying liquid structure of the compounds, such as the degree of charge organization among the constituent ions. Traditional techniques for experimentally assessing charge organization are specialized and not readily available for routine measurements. This represents a significant roadblock in elucidating these correlations. We use a combination of transmission and polarized-ATR infrared spectroscopy to measure the degree of charge organization for ionic liquids. The technique is illustrated with a family of 1-alkyl-3-methylimidazolium trifluoromethanesulfonate ionic liquids at 30 °C. As expected, the amount of charge organization decreases as the alkyl side chain is lengthened, highlighting the important role of short-range repulsive interactions in defining quasilattice structure. Inherent limitations of the method are identified and discussed. The quantitative measurements of charge organization are then correlated with trends in the transport properties of the compounds to highlight the relationship between charge and momentum transport and the underlying liquid structure. Most research laboratories possess infrared spectrometers capable of conducting these measurements; thus, the proposed method may represent a cost-effective solution for routinely measuring charge organization in ionic liquids.

  15. Simple SAR demonstrator

    NASA Astrophysics Data System (ADS)

    Kulpa, Krzysztof; Misiurewicz, Jacek; Baranowski, Piotr; Wojdołowicz, Grzegorz

    2008-01-01

    In this paper we present a simple SAR radar demonstrator build using commercially available (COTS) components. For the microwave analog front end, a standard police radar microwave head has been used. The Motorola DSP processor board, equipped with ADC and DAC, has been used for generating of modulating signal and for signal acquisition. The raw radar signal (I and Q components) have been recorded on 2.5" HDD. The signal processing has been performed on standard PC computer after copying the recorded data. The aim of constructing simple and relatively cheap demonstrator was to provide the students the real-life unclassified radar signals and motivate them to test and develop various kinds of SAR and ISAR algorithms, including image formation, motion compensation and autofocusing. The simple microwave frontend hardware has a lot of non-idealities, so for obtaining nice SAR image it was necessary to develop the number of correction algorithms at the calibration stage. The SAR demonstrator have been tested using car as a moving platform. The flight tests with a small airborne platform are planned for the summer.

  16. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2003-01-01

    Seawater and natural brines accounted for about 60 percent of U.S. magnesium compounds production during 2002. Dead-burned and caustic-calcined magnesias were recovered from seawater by Premier Chemicals in Florida. They were also recovered from well brines in Michigan by Dow Chemical, Martin Marietta Magnesia Specialties and Rohm & Haas. And they were recovered from magnesite in Nevada by Premier Chemicals.

  17. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2006-01-01

    In 2005, seawater and natural brines accounted for 51% of US magnesium compounds production. World magnesia production was estimated to be 14.5 Mt. Most of the production came from China, North Korea, Russia and Turkey. Although no specific production figures are available, Japan and the United States are estimated to account for almost one-half of the world's capacity from seawater and brines.

  18. Morphology and Ionic Conductivity of Block Copolymer--Ionic Liquid Systems

    NASA Astrophysics Data System (ADS)

    Hoarfrost, M. L.; Virgili, J. M.; Kerr, J. B.; Segalman, R. A.

    2009-03-01

    Block copolymer--ionic liquid systems are of interest for ion exchange membranes due to the ionic conductivity and thermal stability of the ionic liquid combined with the thermal stability and morphological control arising from a structural component in a block copolymer. It is anticipated that the morphology and connectivity of the resulting structural and ionic liquid-containing nanodomains will affect conduction properties. This relationship was investigated for poly(styrene-b-2-vinylpyridine) (S2VP) in ionic liquids composed of varying molar ratios of imidazole and bis(trifluoromethanesulfonyl)imide (Im:TFSI). A stoichiometrically balanced ionic liquid (1:1 Im:TFSI) swells the 2VP lamellar domains for copolymer concentrations as low as 60wt%. With 9:1 Im:TFSI the lamellar structure tolerates more swelling, forming lamellar structures with as little as 30wt% copolymer. Ionic conductivities were derived from AC impedance measurements. The S2VP-Im:TFSI systems, characterized by microphase separated domains, demonstrate ionic conductivities comparable to those of P2VP--ionic liquid systems when normalized by 2VP (monomer) to Im:TFSI ratio.

  19. IMPROVED SYNTHESIS OF ROOM TEMPERATURE IONIC LIQUIDS

    EPA Science Inventory

    Room temperature ionic liquids (RTILs), molten salts comprised of N-alkylimidazolium cations and various anions, have received significant attention due to their commercial potential in a variety of chemical applications especially as substitutes for conventional volatile organic...

  20. Nanoscale Ionic Aggregate Morphology in Zwitterionic Copolymers

    NASA Astrophysics Data System (ADS)

    Choi, Jae-Hong; Huyck, Rebecca; Salas-de La Cruz, David; Long, Timothy E.; Winey, Karen I.

    2009-03-01

    The morphology of two different zwitterionic copolymers, poly(sulfobetaine methacrylate-ran-butyl acrylate), and poly(sulfobetaine methacrylamide-ran-butyl acrylate) are investigated as a function of the mol % content of SBMA (7 and 9 mol %) and SBMAm (6, 10 and 13 mol %), respectively. In both copolymers, X-ray scattering results show a new structure in the material arising from ionic aggregates. The sizes of the ionic aggregates are obtained through the scattering model. The sizes of the ionic aggregates increase as the ion content increases. The application of scanning transmission electron microscopy to the study of ionomer morphology has enabled direct, model-independent visualization of the ionic aggregates. The correlation between X-ray scattering results and the real space imaging for morphology of these zwitterionic copolymers will be presented.

  1. Ionic Liquid-Based Microemulsions in Catalysis.

    PubMed

    Hejazifar, Mahtab; Earle, Martyn; Seddon, Kenneth R; Weber, Stefan; Zirbs, Ronald; Bica, Katharina

    2016-12-16

    The design and properties of surface-active ionic liquids that are able to form stable microemulsions with heptane and water are presented, and their promise as reaction media for thermomorphic palladium-catalyzed cross-coupling reactions is demonstrated.

  2. Ionic liquid polyoxometalates as light emitting materials

    SciTech Connect

    Ortiz-acosta, Denisse; Del Sesto, Rico E; Scott, Brian; Bennett, Bryan L; Purdy, Geraldine M; Muenchausen, Ross E; Mc Kigney, Edward; Gilbertson, Robert

    2008-01-01

    The low melting point, negligible vapor pressure, good solubility, and thermal and chemical stability make ionic liquids useful materials for a wide variety of applications. Polyoxometalates are early transition metal oxygen clusters that can be synthesized in many different sizes and with a variety of heterometals. The most attractive feature of POMs is that their physical properties, in particular electrical, magnetic, and optical properties, can be easily modified following known procedures. It has been shown that POMs can exhibit cooperative properties, as superconductivity and energy transfer. POM ionic liquids can be obtained by selecting the appropliate cation. Different alkyl ammonium and alkyl phosphonium salts are being used to produce new POM ionic liquids together with organic or inorganic luminescent centers to design light emitting materials. Ammonium and phosphonium cations with activated, polymerizable groups are being used to further polymerize the ionic liquid into transparent, solid materials with high metal density.

  3. Phosphonium-based ionic liquids and uses

    SciTech Connect

    Del Sesto, Rico E; Koppisch, Andrew T; Lovejoy, Katherine S; Purdy, Geraldine M

    2014-12-30

    Phosphonium-based room temperature ionic liquids ("RTILs") were prepared. They were used as matrices for Matrix-Assisted Laser Desorption Ionization (MALDI) mass spectrometry and also for preparing samples of dyes for analysis.

  4. Fast Ignition and Sustained Combustion of Ionic Liquids

    NASA Technical Reports Server (NTRS)

    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.

  5. Iron hydroxyl phosphate microspheres: Microwave-solvothermal ionic liquid synthesis, morphology control, and photoluminescent properties

    SciTech Connect

    Cao Shaowen; Zhu Yingjie; Cui Jingbiao

    2010-07-15

    A variety of iron hydroxyl phosphate (NH{sub 4}Fe{sub 2}(PO{sub 4}){sub 2}OH.2H{sub 2}O) nanostructures such as solid microspheres, microspheres with the core in the hollow shell, and double-shelled hollow microspheres were synthesized by a simple one-step microwave-solvothermal ionic liquid method. The effects of the experimental parameters on the morphology and crystal phase of the resultant materials were investigated. Structural dependent photoluminescence was observed from the double-shelled hollow microspheres and the underlying mechanisms were discussed. - Graphical abstract: A variety of iron hydroxyl phosphate (NH{sub 4}Fe{sub 2}(PO{sub 4}){sub 2}OH.2H{sub 2}O) nanostructures were synthesized by a simple one-step microwave-solvothermal ionic liquid method. Structural dependent photoluminescence was observed from the double-shelled hollow microspheres.

  6. Geminal Brønsted Acid Ionic Liquids as Catalysts for the Mannich Reaction in Water

    PubMed Central

    He, Leqin; Qin, Shenjun; Chang, Tao; Sun, Yuzhuang; Zhao, Jiquan

    2014-01-01

    Quaternary ammonium geminal Brønsted acid ionic liquids (GBAILs) based on zwitterionic 1,2-bis[N-methyl-N-(3-sulfopropyl)-alkylammonium]ethane (where the carbon number of the alkyl chain is 4, 8, 10, 12, 14, 16, or 18) and p-toluenesulfonic acid monohydrate were synthesized. The catalytic ionic liquids were applied in three-component Mannich reactions with an aldehyde, ketone, and amine at 25 °C in water. The effects of the type and amount of catalyst and reaction time as well as the scope of the reaction were investigated. Results showed that GBAIL-C14 has excellent catalytic activity and fair reusability. The catalytic procedure was simple, and the catalyst could be recycled seven times via a simple separation process without noticeable decreases in catalytic activity. PMID:24837832

  7. Superbase-derived protic ionic liquids

    DOEpatents

    Dai, Sheng; Luo, Huimin; Baker, Gary A.

    2013-09-03

    Protic ionic liquids having a composition of formula (A.sup.-)(BH.sup.+) wherein A.sup.- is a conjugate base of an acid HA, and BH.sup.+ is a conjugate acid of a superbase B. In particular embodiments, BH.sup.+ is selected from phosphazenium species and guanidinium species encompassed, respectively, by the general formulas: ##STR00001## The invention is also directed to films and membranes containing these protic ionic liquids, with particular application as proton exchange membranes for fuel cells.

  8. Ionic conductors for solid oxide fuel cells

    SciTech Connect

    Krumpelt, M.; Bloom, I.D.; Pullockaran, J.D.; Myles, K.M.

    1991-12-31

    An electrolyte that operates at temperatures ranging from 600{degree}C to 800{degree}C is discussed. The electrolyte conducts charge ionically as well as electronically. The ionic conductors include molecular framework structures having planes or channels large enough to transport oxides or hydrated protons and having net-positive or net-negative charges. Representative molecular framework structures include substituted aluminum phosphates, orthosilicates, silicoaluminates, cordierites, apatites, sodalites, and hollandites.

  9. Ionic liquids in the synthesis of nanoobjects

    NASA Astrophysics Data System (ADS)

    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.

  10. Ionic conductors for solid oxide fuel cells

    DOEpatents

    Krumpelt, Michael; Bloom, Ira D.; Pullockaran, Jose D.; Myles, Kevin M.

    1993-01-01

    An electrolyte that operates at temperatures ranging from 600.degree. C. to 800.degree. C. is provided. The electrolyte conducts charge ionically as well as electronically. The ionic conductors include molecular framework structures having planes or channels large enough to transport oxides or hydrated protons and having net-positive or net-negative charges. Representative molecular framework structures include substituted aluminum phosphates, orthosilicates, silicoaluminates, cordierites, apatites, sodalites, and hollandites.

  11. Influence of the counteranion on the ability of 1-dodecyl-3-methyltriazolium ionic liquids to form mesophases

    DOE PAGES

    Stappert, Kathrin; Unal, Derya; Spielberg, Eike T.; ...

    2014-11-25

    The influence of the counteranion on the ability of the mesogenic cation 1-methyl-3-dodecyl-triazolium to form mesophases is explored. To that avail, salts of the cation with anions of different size, shape, and hydrogen bonding capability such as Cl–, Br–, I–, I3–, PF6–, and Tf2N– [bis(trifluorosulfonyl)amide] were synthesized and characterized. The crystal structures of the bromide, the iodide, and the triiodide reveal that the cations form bilayers with cations oriented in opposite directions featuring interdigitated alkyl tails. Within the layers, the cations are separated by anions. The rod-shaped triiodide anion forces the triazolium cation to align with it in this crystalmore » structure but due to its space requirement reduces the alkyl chain interdigitation which prevents the formation of a mesophase. Rather the compound transforms directly from a crystalline solid to an (ionic) liquid like the analogous bis(trifluorosulfonyl)amide. In contrast, the simple halides and the hexafluorophosphate form liquid crystalline phases. As a result, their clearing points shift with increasing anion radius to lower temperatures.« less

  12. Extraction of testosterone and epitestosterone in human urine using aqueous two-phase systems of ionic liquid and salt.

    PubMed

    He, Chiyang; Li, Shehong; Liu, Huwei; Li, Kean; Liu, Feng

    2005-08-05

    Based on aqueous two-phase systems (ATPS) consisting of 1-butyl-3-methylimidazolium chloride, a hydrophilic ionic liquid (IL), and K2HPO4, a new and simple extraction technique, coupled with a reversed-phase high performance liquid chromatography (RP-HPLC), was developed for the simultaneous concentration and analysis of testosterone (T) and epitestosterone (ET) in human urine. Under the optimal conditions, the extraction efficiencies for both analytes were 80-90% in a one-step extraction. The method required only 3.0 mL of urine and a single hydrolysis/deproteinization/extraction step followed by direct injection of the IL-rich upper phase into HPLC system for analysis. The method has been satisfactorily applied to the analysis of T and ET in human urine with detection limits of 1 ng/mL and linear ranges of 10-500 ng/mL for both compounds. Compared with conventional liquid-liquid extraction or solid phase extraction, this new method is much "greener" due to no use of volatile organic solvent and low consumption of IL. The proposed extraction technique opens up new possibilities in the separation of other drugs.

  13. Influence of the counteranion on the ability of 1-dodecyl-3-methyltriazolium ionic liquids to form mesophases

    SciTech Connect

    Stappert, Kathrin; Unal, Derya; Spielberg, Eike T.; Mudring, Anja -Verena

    2014-11-25

    The influence of the counteranion on the ability of the mesogenic cation 1-methyl-3-dodecyl-triazolium to form mesophases is explored. To that avail, salts of the cation with anions of different size, shape, and hydrogen bonding capability such as Cl, Br, I, I3, PF6, and Tf2N [bis(trifluorosulfonyl)amide] were synthesized and characterized. The crystal structures of the bromide, the iodide, and the triiodide reveal that the cations form bilayers with cations oriented in opposite directions featuring interdigitated alkyl tails. Within the layers, the cations are separated by anions. The rod-shaped triiodide anion forces the triazolium cation to align with it in this crystal structure but due to its space requirement reduces the alkyl chain interdigitation which prevents the formation of a mesophase. Rather the compound transforms directly from a crystalline solid to an (ionic) liquid like the analogous bis(trifluorosulfonyl)amide. In contrast, the simple halides and the hexafluorophosphate form liquid crystalline phases. As a result, their clearing points shift with increasing anion radius to lower temperatures.

  14. The distillation and volatility of ionic liquids.

    PubMed

    Earle, Martyn J; Esperança, José M S S; Gilea, Manuela A; Lopes, José N Canongia; Rebelo, Luís P N; Magee, Joseph W; Seddon, Kenneth R; Widegren, Jason A

    2006-02-16

    It is widely believed that a defining characteristic of ionic liquids (or low-temperature molten salts) is that they exert no measurable vapour pressure, and hence cannot be distilled. Here we demonstrate that this is unfounded, and that many ionic liquids can be distilled at low pressure without decomposition. Ionic liquids represent matter solely composed of ions, and so are perceived as non-volatile substances. During the last decade, interest in the field of ionic liquids has burgeoned, producing a wealth of intellectual and technological challenges and opportunities for the production of new chemical and extractive processes, fuel cells and batteries, and new composite materials. Much of this potential is underpinned by their presumed involatility. This characteristic, however, can severely restrict the attainability of high purity levels for ionic liquids (when they contain poorly volatile components) in recycling schemes, as well as excluding their use in gas-phase processes. We anticipate that our demonstration that some selected families of commonly used aprotic ionic liquids can be distilled at 200-300 degrees C and low pressure, with concomitant recovery of significant amounts of pure substance, will permit these currently excluded applications to be realized.

  15. Aqueous Solutions of Ionic Liquids: Microscopic Assembly.

    PubMed

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

    2016-02-03

    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.

  16. OsO(4) in ionic liquid [Bmim]PF(6): a recyclable and reusable catalyst system for olefin dihydroxylation. remarkable effect of DMAP.

    PubMed

    Yao, Qingwei

    2002-06-27

    [reaction: see text] The combination of the ionic liquid [bmim]PF(6) and DMAP provides a most simple and practical approach to the immobilization of OsO(4) as catalyst for olefin dihydroxylation. Both the catalyst and the ionic liquid can be repeatedly recycled and reused in the dihydroxylation of a variety of olefins with only a very slight drop in catalyst activity.

  17. New pyridinium-based ionic liquid as an excellent solvent-catalyst system for the one-pot three-component synthesis of 2,3-disubstituted quinolines.

    PubMed

    Anvar, Salma; Mohammadpoor-Baltork, Iraj; Tangestaninejad, Shahram; Moghadam, Majid; Mirkhani, Valiollah; Khosropour, Ahmad Reza; Landarani Isfahani, Amir; Kia, Reza

    2014-03-10

    The synthesis of a variety of 2,3-disubstituted quinolines has been achieved successfully via a one-pot three-component reaction of arylamines, arylaldehydes and aliphatic aldehydes in the presence of butylpyridinium tetrachloroindate(III), [bpy][InCl4], ionic liquid as a green catalyst and solvent. Mild conditions with excellent conversions, and simple product isolation procedure are noteworthy advantages of this method. The recyclability of the ionic liquid makes this protocol environmentally benign.

  18. Ionic Model Approach to Battery Voltage of NaMO2

    NASA Astrophysics Data System (ADS)

    Kobayashi, Wataru; Moritomo, Yutaka

    2014-10-01

    NaMO2 (M = Ti, V, Cr, Mn, Fe, Co, and Ni) with a layered rock-salt structure exhibits high battery voltage (V) and capacity (Q), and is considered to be a promising cathode material for sodium ion secondary batteries (SIBs). Among the battery parameters, V is directly related to the electronic structure of the compounds. Here, we apply the ionic model proposed by Torrance et al. [http://dx.doi.org/10.1016/0921-4534(91)90534-6, Physica C 182, 351 (1991)] to NaMO2 and estimated V using structural parameters. The ionic model reproduces the global feature of the M-dependence of V. This analysis suggests that an electron is removed from the O 2p state in the charge process in the late transition metal compounds (M = Mn-Ni).

  19. Ionic waves in animal tissues

    NASA Astrophysics Data System (ADS)

    Nobili, Renato

    1987-02-01

    A proof is given that self-sustaining ionic-wave propagations-heuristically inferred by the author in a previous paper [Phys. Rev. A 32, 3618 (1985)] concerning a new holographic theory of animal memory-are possible in animal tissues at normal physiological conditions. The proof is obtained by standard electrochemical methods purely on the basis of well-known properties of cell membranes and of molecular devices found in them. It is shown that interstitial pockets filled with extracellular fluid, when viewed as functional units dispersed all over the cell tissue, promote ion currents proportionally to linear combinations of macroscopic sodium and potassium concentration gradients. Oscillations of sodium and potassium macroscopic concentrations prove to be possible thanks to the voltage-driven amplification function for ion fluxes exerted by Na+-K+-ATPase (adenosinetriphosphatase) pumps and to the feedback control role exerted by the (Na+ antiports Ca2+)-->(Ca2+ activates K+) channel system. All steps in deriving the wave equations are coarse-graining invariant; this ensures the correctness of the macroscopic view in treating the problem. Theoretical wave patterns and their general features are in excellent agreement with EEG (electroencephalogram) patterns detected on brain cortices and on scalps. Epileptic foci artificially generated by injection of Na+ ions into glial tissue and inhibition of EEG by K+ superfusion of brain cortex, are correctly accounted for by the theory.

  20. Ionic liquids in separation techniques.

    PubMed

    Berthod, A; Ruiz-Angel, M J; Carda-Broch, S

    2008-03-14

    The growing interest in ionic liquids (ILs) has resulted in an exponentially increasing production of analytical applications. The potential of ILs in chemistry is related to their unique properties as non-molecular solvents: a negligible vapor pressure associated to a high thermal stability. ILs found uses in different sub-disciplines of analytical chemistry. After drawing a rapid picture of the physicochemical properties of selected ILs, this review focuses on their use in separation techniques: gas chromatography (GC), liquid chromatography (LC) and electrophoretic methods (CE). In LC and CE, ILs are not used as pure solvents, but rather diluted in aqueous solutions. In this situation ILs are just salts. They are dual in nature. Too often the properties of the cations are taken as the properties of the IL itself. The lyotropic theory is recalled and the effects of a chaotropic anion are pointed out. Many results can be explained considering all ions present in the solution. Ion-pairing and ion-exchange mechanisms are always present, associated with hydrophobic interactions, when dealing with IL in diluted solutions. Chromatographic and electrophoretic methods are also mainly employed for the control and monitoring of ILs. These methods are also considered. ILs will soon be produced on an industrial scale and it will be necessary to develop reliable analytical procedures for their analysis and control.

  1. Simple Autonomous Chaotic Circuits

    NASA Astrophysics Data System (ADS)

    Piper, Jessica; Sprott, J.

    2010-03-01

    Over the last several decades, numerous electronic circuits exhibiting chaos have been proposed. Non-autonomous circuits with as few as two components have been developed. However, the operation of such circuits relies on the non-ideal behavior of the devices used, and therefore the circuit equations can be quite complex. In this paper, we present two simple autonomous chaotic circuits using only opamps and linear passive components. The circuits each use one opamp as a comparator, to provide a signum nonlinearity. The chaotic behavior is robust, and independent of nonlinearities in the passive components. Moreover, the circuit equations are among the algebraically simplest chaotic systems yet constructed.

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

    PubMed

    Li, Zhonghao; Taubert, Andreas

    2009-11-18

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

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

    DOEpatents

    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.

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

    PubMed

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

    2016-01-29

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

  5. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2002-01-01

    Seawater and natural brines accounted for about 60% of US magnesium compounds production in 2001. Dead-burned and caustic-calcined magnesias were recovered from seawater in Florida by Premier Chemicals. They were also recovered from Michigan well brines by Dow Chemical, Martin Marietta Magnesia Specialties and Rohm & Haas. And Premier Chemicals recovered dead-burned and caustic-calcined magnesias from magnesite in Nevada. Reilly Industries and Great Salt Lake Minerals recovered magnesium chloride brines from the Great Salt Lake in Utah.

  6. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2011-01-01

    Seawater and natural brines accounted for about 54 percent of U.S. magnesium compounds production in 2010. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Magnesia in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Magnesia. Intrepid Potash-Wendover and Great Salt Lake Minerals Corp. recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from seawater by SPI Pharma in Delaware and Premier Magnesia in Florida, and by Martin Marietta from its operation mentioned above.

  7. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2010-01-01

    Seawater and natural brines accounted for about 40 percent of U.S. magnesium compounds production in 2009. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Chemicals in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Chemicals. Intrepid Potash-Wendover, and Great Salt Lake Minerals Corp. recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from seawater by SPI Pharma in Delaware and Premier Chemicals in Florida, and by Martin Marietta from its operation mentioned above.

  8. Novel alkylimidazolium/vanadium pentoxide intercalation compounds with excellent adsorption performance for methylene blue

    SciTech Connect

    Kong Aiguo; Ding Yongjie; Wang Ping; Zhang Hengqiang; Yang Fan; Shan Yongkui

    2011-02-15

    Novel alkylimidazolium-intercalated V{sub 2}O{sub 5} compounds were synthesized by a redox reaction between iodide ion and V{sub 2}O{sub 5}. The X-ray photoelectron spectroscopy and the diffuse reflectance UV-vis spectrometry experiments reveal that the vanadium in the intercalated V{sub 2}O{sub 5} products was partially reduced by an iodide ion and the resultant iodine can be removed in the final products. The transmission electron microscope observation and X-ray diffraction analysis testify that the prepared alkylimidazolium/V{sub 2}O{sub 5} intercalation compounds have typical lamellar structure with different d{sub 100} interlayer spacing values and the special straw-like nanofiber morphology with the length of 0.5-10 {mu}m. Systematic investigation indicates that new intercalation compounds possess the extraordinary adsorption performance for methylene blue in an aqueous solution. -- Graphical abstract: The alkylimidazolium-intercalated V{sub 2}O{sub 5} compounds with special straw-like nanofiber morphology were synthesized by a redox reaction between iodide ion and V{sub 2}O{sub 5}, which show the excellent adsorption performance for methylene blue in an aqueous medium. Display Omitted Research highlights: {yields} Novel alkylimidazolium-intercalated V{sub 2}O{sub 5} compounds. {yields} A simple preparation method by a redox reaction between iodide ion in ionic liquid and V{sub 2}O{sub 5}. {yields} The excellent adsorption performance for methylene blue in an aqueous medium.

  9. Surface confined ionic liquid as a stationary phase for HPLC

    SciTech Connect

    Wang, Qian; Baker, Gary A; Baker, Sheila N; Colon, Luis

    2006-01-01

    Trimethoxysilane ionosilane derivatives of room temperature ionic liquids based on alkylimidazolium bromides were synthesized for attachment to silica support material. The derivatives 1-methyl-3-(trimethoxysilylpropyl)imidazolium bromide and 1-butyl-3-(trimethoxysilylpropyl)imidazolium bromide were used to modify the surface of 3 {micro}m diameter silica particles to act as the stationary phase for HPLC. The modified particles were characterized by thermogravimetric analysis (TGA) and {sup 13}C and {sup 29}Si NMR spectroscopies. The surface modification procedure rendered particles with a surface coverage of 0.84 {micro}mol m{sup -2} for the alkylimidazolium bromide. The ionic liquid moiety was predominantly attached to the silica surface through two siloxane bonds of the ionosilane derivative (63%). Columns packed with the modified silica material were tested under HPLC conditions. Preliminary evaluation of the stationary phase for HPLC was performed using aromatic carboxylic acids as model compounds. The separation mechanism appears to involve multiple interactions including ion exchange, hydrophobic interaction, and other electrostatic interactions.

  10. Designer ionic liquid crystals based on congruently shaped guanidinium sulfonates.

    PubMed

    Butschies, Martin; Frey, Wolfgang; Laschat, Sabine

    2012-03-05

    Ionic liquid crystals are mesogenic compounds that consist of cations and anions, usually rod-like cations and spherical anions. Herein we report a new method for the synthesis of ionic liquid crystals by using cations and anions of the same molecular shape with oppositely charged head groups. Thus, 4-alkoxyphenylpentamethylguanidinium 4-alkoxyphenylsulfonate ion pairs have been synthesised. 4-Alkoxyphenylpentamethylguanidinium iodides were also prepared to determine the influence of congruently shaped anions, in comparison with their spherical counterparts, on mesophase behaviour, which was investigated by differential scanning calorimetry (DSC), polarising optical microscopy (POM) and X-ray diffraction (XRD). All the liquid crystalline salts exhibit smectic A mesophases with strongly interdigitated bilayer structures. The guanidinium sulfonate ion pairs show mesomorphic properties from shorter alkyl chain lengths (≥C(9)) and lower melting points (≈10 K), whereas the corresponding guanidinium iodides are liquid crystalline for longer alkyl chain lengths (≥C(14)). For chains with ≥C(18), however, the mesophase range decreases for the sulfonate ion pairs, but not for the iodide salts.

  11. Ferrocenyl-phosphonium ionic liquids - synthesis, characterisation and electrochemistry.

    PubMed

    Kübler, Paul; Sundermeyer, Jörg

    2014-03-07

    New unsymmetrically substituted ferrocenyl-phosphonium ionic liquids (ILs) [FcPR2R']NTf2 are synthesized by two or three step syntheses starting from ferrocene, Fc = (C5H5)Fe(C5H4); R = Me, (n)Bu, (n)Hex, Ph; R' = Me, (n)Pr, (n)Bu, Ph; NTf2 = N(SO2CF3)2. The selective synthesis of alkyl phosphines FcPR2via a Friedel-Crafts phosphorylation is highlighted as an alternative for the standard protocol commonly used for ferrocenyl arylphosphines involving lithiation of FcH followed by phosphorylation. The influence of the P-substituents on thermal stability, electrochemical potential, chemical shift, and UV-Vis absorption behavior of the ILs is studied. The phosphonium group acts both as an ionic tag and as an electron-withdrawing substituent directly bound at the Cp-ring position. Therefore the title compounds are attractive for further studies to use them as tunable redox mediators for (photo)electrochemical devices such as dye sensitized solar cells (DSSCs) or redox flow batteries.

  12. Ionic liquids in solid-phase microextraction: a review.

    PubMed

    Ho, Tien D; Canestraro, Anthony J; Anderson, Jared L

    2011-06-10

    Solid-phase microextraction (SPME) has undergone a surge in popularity within the field of analytical chemistry in the past two decades since its introduction. Owing to its nature of extraction, SPME has become widely known as a quick and cost-effective sample preparation technique. Although SPME has demonstrated extraordinary versatility in sampling capabilities, the technique continues to experience a tremendous growth in innovation. Presently, increasing efforts have been directed towards the engineering of novel sorbent material in order to expand the applicability of SPME for a wider range of analytes and matrices. This review highlights the application of ionic liquids (ILs) and polymeric ionic liquids (PILs) as innovative sorbent materials for SPME. Characterized by their unique physico-chemical properties, these compounds can be structurally-designed to selectively extract target analytes based on unique molecular interactions. To examine the advantages of IL and PIL-based sorbent coatings in SPME, the field is reviewed by gathering available experimental data and exploring the sensitivity, linear calibration range, as well as detection limits for a variety of target analytes in the methods that have been developed.

  13. (Eco)toxicity and biodegradability of protic ionic liquids.

    PubMed

    Oliveira, Maria V S; Vidal, Bruna T; Melo, Claudia M; de Miranda, Rita de C M; Soares, Cleide M F; Coutinho, João A P; Ventura, Sónia P M; Mattedi, Silvana; Lima, Álvaro S

    2016-03-01

    Ionic liquids (ILs) are often claimed to be "environmentally friendly" compounds however, the knowledge of their potential toxicity towards different organisms and trophic levels is still limited, in particular when protic ionic liquids (PILs) are addressed. This study aims to evaluate the toxicity against various microorganisms and the biodegradability of four PILs namely, N-methyl-2-hydroxyethylammonium acetate, m-2-HEAA; N-methyl-2-hydroxyethylammonium propionate, m-2-HEAPr; N-methyl-2-hydroxyethylammonium butyrate, m-2-HEAB; and N-methyl-2-hydroxyethylammonium pentanoate, m-2-HEAP. The antimicrobial activity was determined against the two bacteria, Sthaplylococcus aureus ATCC-6533 and Escherichia coli CCT-0355; the yeast Candida albicans ATCC-76645; and the fungi Fusarium sp. LM03. The toxicity of all PILs was tested against the aquatic luminescent marine bacterium Vibrio fischeri using the Microtox(®) test. The impact of the PILs was also studied regarding their effect on lettuce seeds (Lactuta sativa). The biodegradability of these PILs was evaluated using the ratio between the biochemical oxygen demand (BOD) and the chemical oxygen demand (COD). The results show that, in general, the elongation of the alkyl chain tends to increase the negative impact of the PILs towards the organisms and biological systems under study. According to these results, m-2-HEAA and m-2-HEAP are the less and most toxic PILs studied in this work, respectively. Additionally, all the PILs have demonstrated low biodegradability.

  14. Simple stochastic simulation.

    PubMed

    Schilstra, Maria J; Martin, Stephen R

    2009-01-01

    Stochastic simulations may be used to describe changes with time of a reaction system in a way that explicitly accounts for the fact that molecules show a significant degree of randomness in their dynamic behavior. The stochastic approach is almost invariably used when small numbers of molecules or molecular assemblies are involved because this randomness leads to significant deviations from the predictions of the conventional deterministic (or continuous) approach to the simulation of biochemical kinetics. Advances in computational methods over the three decades that have elapsed since the publication of Daniel Gillespie's seminal paper in 1977 (J. Phys. Chem. 81, 2340-2361) have allowed researchers to produce highly sophisticated models of complex biological systems. However, these models are frequently highly specific for the particular application and their description often involves mathematical treatments inaccessible to the nonspecialist. For anyone completely new to the field to apply such techniques in their own work might seem at first sight to be a rather intimidating prospect. However, the fundamental principles underlying the approach are in essence rather simple, and the aim of this article is to provide an entry point to the field for a newcomer. It focuses mainly on these general principles, both kinetic and computational, which tend to be not particularly well covered in specialist literature, and shows that interesting information may even be obtained using very simple operations in a conventional spreadsheet.

  15. Synergistic Effects Between Phosphonium-Alkylphosphate Ionic Liquids and Zinc Dialkyldithiophosphate (ZDDP) as Lubricant Additives

    DOE PAGES

    Qu, Jun; Barnhill, William C.; Luo, Huimin; ...

    2015-07-14

    Unique synergistic effects between phosphonium-alkylphosphate ionic liquids and zinc dialkyldithiophosphate (ZDDP) are discovered when used together as lubricant additives, resulting in significant friction and wear reduction along with distinct tribofilm composition and mechanical properties. The synergism is attributed to the 30-70× higher-than-nominal concentrations of hypothetical new compounds (via anion exchange between IL and ZDDP) on the fluid surface/interface.

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

    PubMed

    Łuczak, Justyna; Paszkiewicz, Marta; Krukowska, Anna; Malankowska, Anna; Zaleska-Medynska, Adriana

    2016-01-01

    Ionic liquids (ILs) are widely applied to prepare metal nanoparticles and 3D semiconductor microparticles. Generally, they serve as a structuring agent or reaction medium (solvent), however it was also demonstrated that ILs can play a role of a co-solvent, metal precursor, reducing as well as surface modifying agent. The crucial role and possible types of interactions between ILs and growing particles have been presented in the Part 1 of this review paper. Part 2 of the paper gives a comprehensive overview of recent experimental studies dealing with application of ionic liquids for preparation of metal and semiconductor based nano- and microparticles. A wide spectrum of preparation routes using ionic liquids is presented, including precipitation, sol-gel technique, hydrothermal method, nanocasting and ray-mediated methods (microwave, ultrasound, UV-radiation and γ-radiation). It was found that ionic liquids formed of a 1-butyl-3-methylimidazolium [BMIM] combined with tetrafluoroborate [BF4], hexafluorophosphate [PF6], and bis(trifluoromethanesulfonyl)imide [Tf2N] are the most often used ILs in the synthesis of nano- and microparticles, due to their low melting temperature, low viscosity and good transportation properties. Nevertheless, examples of other IL classes with intrinsic nanoparticles stabilizing abilities such as phosphonium and ammonium derivatives are also presented. Experimental data revealed that structure of ILs (both anion and cation type) affects the size and shape of formed metal particles, and in some cases may even determine possibility of particles formation. The nature of the metal precursor determines its affinity to polar or nonpolar domains of ionic liquid, and therefore, the size of the nanoparticles depends on the size of these regions. Ability of ionic liquids to form varied extended interactions with particle precursor as well as other compounds presented in the reaction media (water, organic solvents etc.) provides nano- and

  17. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2007-01-01

    Seawater and natural brines accounted for about 52 percent of U.S. magnesium compounds production in 2006. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from sea-water by Premier Chemicals in Florida; from well brines in Michigan by Martin Marietta and Rohm and Haas; and from magnesite in Nevada by Premier Chemicals. Intrepid Potash-Wendover and Great Salt Lake Minerals recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from brucite by Applied Chemical Magnesias in Texas, from seawater by SPI Pharma in Delaware and Premier Chemicals in Florida, and by Martin Marietta and Rohm and Haas from their operations mentioned above. About 59 percent of the magnesium compounds consumed in the United States was used for refractories that are used mainly to line steelmaking furnaces. The remaining 41 percent was consumed in agricultural, chemical, construction, environmental and industrial applications.

  18. Phenolic compounds in Brassica vegetables.

    PubMed

    Cartea, María Elena; Francisco, Marta; Soengas, Pilar; Velasco, Pablo

    2010-12-30

    Phenolic compounds are a large group of phytochemicals widespread in the plant kingdom. Depending on their structure they can be classified into simple phenols, phenolic acids, hydroxycinnamic acid derivatives and flavonoids. Phenolic compounds have received considerable attention for being potentially protective factors against cancer and heart diseases, in part because of their potent antioxidative properties and their ubiquity in a wide range of commonly consumed foods of plant origin. The Brassicaceae family includes a wide range of horticultural crops, some of them with economic significance and extensively used in the diet throughout the world. The phenolic composition of Brassica vegetables has been recently investigated and, nowadays, the profile of different Brassica species is well established. Here, we review the significance of phenolic compounds as a source of beneficial compounds for human health and the influence of environmental conditions and processing mechanisms on the phenolic composition of Brassica vegetables.

  19. Poly(ionic liquid) superabsorbent for polar organic solvents.

    PubMed

    Horne, W Jeffrey; Andrews, Mary A; Terrill, Kelsey L; Hayward, Spenser S; Marshall, Jeannie; Belmore, Kenneth A; Shannon, Matthew S; Bara, Jason E

    2015-05-06

    A simple, polymerized ionic liquid (poly(IL)) based on methylimidazolium cations tethered to a polystyrene backbone exhibits superabsorbent behavior toward polar organic solvents, most notably propylene carbonate (PC) and dimethyl sulfoxide (DMSO), wherein the poly(IL) was observed to swell more than 390 and 200 times (w/w) its original mass, yet absorbs negligible quantities of water, hexanes, and other solvents, many of which were miscible with the IL monomer. Although solubility parameters and dielectric constants are typically used to rationalize such behaviors, we find that poly(IL)-solvent compatibility is most clearly correlated to solvent dipole moment. Poly(IL) superabsorbency is not reliant upon the addition of a cross-linking agent.

  20. Linear mixing rule in screened binary ionic mixtures

    NASA Technical Reports Server (NTRS)

    Chabrier, G.; Ashcroft, N. W.

    1990-01-01

    The validity of the linear mixing rule is examined for the following two cases (1) when the response of the electron gas is taken into account in the effective ionic interaction and (2) when finite-temperature effects are included in the dielectric response of the electrons, i.e., when the ions interact with both temperature- and density-dependent screened Coulomb potentials. It is found that the linear mixing rule remains valid when the electron response is taken into account in the interionic potential at any density, even though the departure from linearity can reach a few percent for the asymmetric mixtures in the region of weak degeneracy for the electron gas. A physical explanation of this behavior is proposed which is based on a simple additional length scale.