Sample records for aprotic ionic liquids

  1. Pronounced structure in confined aprotic room-temperature ionic liquids.

    PubMed

    Hayes, Robert; El Abedin, Sherif Zein; Atkin, Rob

    2009-05-21

    Room-temperature ionic liquids (ILs) are attracting considerable research interest as replacements for traditional molecular solvents in a diverse range of chemical applications, mostly due to their green characteristics and remarkable physical properties. Previously, we reported the liquid structure of 1-ethyl-3-methylimidazolium acetate confined between mica and an atomic force microscope (AFM) tip, and found that approximately three solvation layers form. In this manuscript, we present new data, derived from similar experiments, for three different aprotic ILs [1-butyl-3-methylimidazolium hexafluorphosphate (BMIm PF6), 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl) imide (EMIm TSFA), and 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl) imide (BMP TSFA)] and between five and six solvation layers are identified depending on the IL species. These new results allow us to make suggestions for molecularly designing IL architectures likely to be suitable for a particular application, depending on whether near surface order is desirable or not. Where mobility of component ions and transfer of species to and from the interface is required (DSSCs, hetereogeneous catalysis, etc.), multiple sterically hindered allylic functional groups could be incorporated to minimize substrate-IL interactions and maximize compressibility of the solvation layers. Conversely, in situations where IL adsorption to the interface is desirable (e.g., lubrication or electrode surface restructuring), symmetric ions with localized charge centers are preferable. PMID:19438273

  2. Ternary polymer electrolytes with 1-methylimidazole based ionic liquids and aprotic solvents

    Microsoft Academic Search

    Jakub Reiter; Ji?í Vondrák; Ji?í Michálek; Zden?k Mi?ka

    2006-01-01

    New polymer gel electrolytes containing ionic liquids were developed for modern chemical power sources—supercapacitors and lithium-ion batteries. Ternary systems polymer–ionic liquid–aprotic solvent as well as materials containing also lithium salts (LiClO4 or LiPF6) were prepared by direct, thermally initiated polymerisation. Poly(2-ethoxyethyl methacrylate) PEOEMA was combined with various ionic liquids based on 1-methylimidazole. Only 1-butyl-3-methylimidazolium hexafluorophosphate BMIPF6 formed a homogenous and

  3. Non-ionogenic amphiphiles in aprotic ionic liquids

    NASA Astrophysics Data System (ADS)

    Zherenkova, L. V.; Komarov, P. V.

    2015-04-01

    Structural properties of the imidazolium ionic liquid-non-ionogenic amphiphile system are studied on the basis of the integral equation theory. The effect of the alkyl substituent lengths of cations and solvent selectivity on the features of amphiphile self-assembly is studied. The need to allow for solvent structure in constructing a theory of phase behavior of amphiphile in ionic liquid is demonstrated. The characteristic scales of structural inhomogeneities of a mixture at the stage of the self-assembly of amphiphile molecules are analyzed. Aggregation characteristics of mixture, particularly medium-field spinodal temperature are calculated, depending on amphiphile concentration.

  4. A comparative study of the terrestrial ecotoxicity of selected protic and aprotic ionic liquids.

    PubMed

    Peric, Brezana; Sierra, Jordi; Martí, Esther; Cruañas, Robert; Garau, Maria Antonia

    2014-08-01

    Ionic liquids (ILs) are a fairly new and very promising group of compounds with a vast variety of possible structures and uses. They are considered to be potentially "green", but their impact on the environment tends to be neglected or not studied enough, especially when it comes to terrestrial ecotoxicity, where there are very few studies performed to date. This work presents a comparative study of the terrestrial ecotoxicity of selected representatives of two ILs groups: a new family of protic ILs (derived from aliphatic amines and organic acids) and some frequently used aprotic ILs (substituted imidazolium and piridinium chlorides). Toxicity of the ILs towards three terrestrial plant species (Allium cepa, Lolium perenne and Raphanus sativus) and soil microorganisms involved in carbon and nitrogen transformation was analyzed. Protic ILs have shown no toxic effect in most of the tests performed. The EC50 values for aprotic ILs are various orders of magnitude lower than the ones for protic ILs in all of the tests. The most toxic ILs are the most complex ones in both of the analyzed groups. Protic ILs seem to have a potential for biodegradation in soil, while aprotic ILs exhibit inhibitory effects towards the carbon transforming microbiota. These findings indicate that protic ILs can be considered as less toxic and safer for the terrestrial environment than the aprotic ILs. PMID:24630250

  5. Water-in-ionic liquid microemulsion formation in solvent mixture of aprotic and protic imidazolium-based ionic liquids.

    PubMed

    Kusano, Takumi; Fujii, Kenta; Hashimoto, Kei; Shibayama, Mitsuhiro

    2014-10-14

    We report that water-in-ionic liquid microemulsions (MEs) are stably formed in an organic solvent-free system, i.e., a mixture of aprotic (aIL) and protic (pIL) imidazolium-based ionic liquids (ILs) containing the anionic surfactant dioctyl sulfosuccinate sodium salt (AOT). Structural investigations using dynamic light, small-angle X-ray, and small-angle neutron scatterings were performed for MEs formed in mixtures of aprotic 1-octyl-3-methylimidazolium ([C8mIm(+)]) and protic 1-alkylimidazolium ([CnImH(+)], n = 4 or 8) IL with a common anion, bis(trifluoromethanesulfonyl)amide ([TFSA(-)]). It was found that the ME structure strongly depends on the mixing composition of the aIL/pIL in the medium. The ME size appreciably increases with increasing pIL content in both [C8mIm(+)][TFSA(-)]/[C8ImH(+)][TFSA(-)] and [C8mIm(+)][TFSA(-)]/[C4ImH(+)][TFSA(-)] mixtures. The size is larger for the n = 8 system than that for the n = 4 system. These results indicate that the shell part of MEs is composed of both AOT and pIL cation, and the ME size can be tuned by pIL content in the aIL/pIL mixtures. PMID:25226398

  6. Aprotic Heterocyclic Anion Triazolide Ionic Liquids - A New Class of Ionic Liquid Anion Accessed by the Huisgen Cycloaddition Reaction

    SciTech Connect

    Thompson, Robert L.; Damodaran, Krishnan; Luebke, David; Nulwala, Hunaid

    2013-06-01

    The triazole core is a highly versatile heterocyclic ring which can be accessed easily with the Cu(I)-catalyzed Huisgen cycloaddition reaction. Herein we present the preparation of ionic liquids that incorporate a 1,2,3-triazolide anion. These ionic liquids were prepared by a facile procedure utilizing a base-labile pivaloylmethyl group at the 1-position, which can act as precursors to 1H- 4-substituted 1,2,3-triazole. These triazoles were then subsequently converted into ionic liquids after deprotonation using an appropriate ionic liquid cation hydroxide. The densities and thermal decompositions of these ionic liquids were measured. These novel ionic liquids have potential applications in gas separations and in metal-free catalysis.

  7. Gelation mechanism of tetra-armed poly(ethylene glycol) in aprotic ionic liquid containing nonvolatile proton source, protic ionic liquid.

    PubMed

    Hashimoto, Kei; Fujii, Kenta; Nishi, Kengo; Sakai, Takamasa; Yoshimoto, Nobuko; Morita, Masayuki; Shibayama, Mitsuhiro

    2015-04-01

    We report the gelation mechanism of tetra-armed prepolymer chains in typical aprotic ionic liquid (aIL), i.e., A-B type cross-end coupling reaction of tetra-armed poly(ethylene glycol)s with amine and activated ester terminals (TetraPEG-NH2 and TetraPEG-NHS, respectively) in 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide ([C2mIm][TFSA]). In the ion gel system, we focused on the pH (or H(+) concentration) dependence of the gelation reaction. We thus applied the protic ionic liquid (pIL), 1-ethylimidazolium TFSA ([C2ImH][TFSA]), as a nonvolatile H(+) source, and added it into the solvent aIL. It was found that the gelation time of TetraPEG ion gel can be successfully controlled from 1 min to 3 h depending on the concentration of pIL (cpIL = 0-3 mM). This suggests that the acid-base properties of TetraPEG-NH2 showing acid-base equilibrium (-NH2 + H(+) ? -NH3(+)) in the solutions play a key role in the gelation process. The acid dissociation constants, pKa's of TetraPEG-NH3(+) and C2ImH(+) (cation of pIL) in aIL were directly determined by potentiometric titration to be 16.4 and 13.7, respectively. This indicates that most of the H(+) ions bind to TetraPEG-NH2 and then C2ImH(+) exists as neutral C2Im. The reaction efficiency of amide bond (cross-linked point) systematically decreased with increasing cpIL, which was reflected to the mechanical strength of the ion gels. From these results, we discuss the gelation mechanism of TetraPEG in aIL to point out the relationship between polymer network structure and [H(+)] in the solutions. PMID:25768427

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

    PubMed

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

    2009-08-18

    Novel supported liquid membranes (SLMs) have been developed by impregnating Nafion and Hyflon membranes with ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BMI-BTSI). These supported liquid membranes were characterized in terms of their ionic liquid uptake behavior, leaching of ionic liquid by water, thermal stability, mechanical properties, glass transition temperature, ion exchange capacity, and proton conductivity. In general, modified membranes are more flexible than unmodified samples due to the plasticization effects of the ionic liquid. However, these supported liquid membranes exhibit a significant increase in their operational stability and proton conductivity over unmodified membranes. We also demonstrate that proton conductivity of these supported liquid membranes allows conduction of protons in anhydrous conditions with conductivity increasing with temperature. Conductivity of up to 3.58 mS cm(-1) has been achieved at 160 degrees C in dry conditions, making these materials promising for various electrochemical applications. PMID:19583225

  9. Study of a Li-air battery having an electrolyte solution formed by a mixture of an ether-based aprotic solvent and an ionic liquid

    NASA Astrophysics Data System (ADS)

    Cecchetto, Laura; Salomon, Mark; Scrosati, Bruno; Croce, Fausto

    2012-09-01

    Recent studies have clearly demonstrated that cyclic and linear carbonates are unstable when used in rechargeable Li-air batteries employing aprotic solvents mostly due to the cathodic formation of superoxide during the oxygen reduction reaction. In particular, it has been ascertained that nucleophilic attack by superoxide anion radical, O2-rad , at O-alkyl carbon is a common mechanism of decomposition of organic carbonates. Moreover, theoretical calculations showed that ether chemical functionalities are stable against nucleophilic substitution induced by superoxide. Aim of this study is to report on a new electrolyte solution for Li-air battery formed by a mixture of an ether-based aprotic solvent with an ionic liquid (IL). The IL-based electrolyte was obtained by mixing the pure ionic liquid N-methyl-(n-butyl) pyrrolidinium bis(trifluoromethane sulfonyl) imide (here denoted as PYR14TFSI) to a 0.91 M solution of lithium triflate (LiCF3SO3) in tetra ethylene glycol dimethyl etcher (TEGDME). We observed that the presence of IL beneficially affects the kinetics and the reversibility of the oxygen reactions involved at the cathode. The most significant result being a lower overvoltage for the charge reaction, compared to a Li/air cell containing the same electrolyte solution without IL.

  10. Effect of water on the transport properties of protic and aprotic imidazolium ionic liquids - an analysis of self-diffusivity, conductivity, and proton exchange mechanism.

    PubMed

    Yaghini, N; Nordstierna, L; Martinelli, A

    2014-05-28

    In this paper we report on the transport properties of protic and aprotic ionic liquids of the imidazolium cation (C2C1Im(+) or C2HIm(+)) and the TFSI(-) or TfO(-) anion as a function of added water. We observe that the self-diffusion coefficient of the ionic species increases upon addition of water, and that the cation diffuses faster than the anion in the entire water concentration range investigated. We also observe that the overall increase of anionic and cationic diffusion coefficients is significant for C2HImTfO while it is rather weak for C2C1ImTFSI, the former being more hydrophilic. Moreover, the difference between cationic and anionic self-diffusivity specifically depends on the structure of the ionic liquid's ions. The degree of ion-ion association has been investigated by comparing the molar conductivity obtained by impedance measurements with the molar conductivity calculated from NMR data using the Nernst-Einstein equation. Our data indicate that the ions are partly dissociated (?imp/?NMR in the range 0.45-0.75) but also that the degree of association decreases in the order C2HImTfO > C2HImTFSI ? C2C1ImTfO > C2C1ImTFSI. From these results, it seems that water finds different sites of interaction in the protic and aprotic ionic liquids, with a strong preference for hydrogen bonding to the -NH group (when available) and a stronger affinity to the TfO anion as compared to the TFSI. For the protic ionic liquids, the analysis of (1)H NMR chemical shifts (upon addition of H2O and D2O, respectively) indicates a water-cation interaction of hydrogen bonding nature. In addition, we could probe proton exchange between the -NH group and deuterated water for the protic cation, which occurs at a significantly faster rate if associated with the TfO anion as compared to the TFSI. PMID:24714867

  11. 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.

  12. Ionic Liquid as a Green Solvent for Lignin

    Microsoft Academic Search

    Yunqiao Pu; Nan Jiang; Arthur J. Ragauskas

    2007-01-01

    This study examined the application of select ionic liquids (ILs) as aprotic green solvents for lignin. Dissolution experiments were carried out employing lignin isolated from pine kraft pulp. Up to 20 wt% lignin could be dissolved in [hmim][CF3SO3], [mmim][MeSO4] and [bmim][MeSO4]. For the [bmim]?containing ionic liquids, the order of lignin solubility for varying anions was: [MeSO4]>Cl?Br?[PF6], indicating that the solubility

  13. Photorheological ionic liquids.

    PubMed

    Avó, João; Cidade, M T; Rodriguez, Vincent; Lima, João C; Parola, A Jorge

    2015-06-01

    Two room temperature ionic liquids (ILs) bearing coumarin and p-hydroxycinnamic acid moieties are synthesized, and their photochemistry is studied in solution and neat conditions. Irradiation at absorption maxima leads to photochemical transformations and results in changes of their rheological properties which are evaluated by rotational rheometry. Samples of ionic liquids are also studied by Hyper-Rayleigh scattering, and the effect of their photochemistry on ionic nanoaggregation is discussed. PMID:25970078

  14. Ionic liquids in tribology.

    PubMed

    Minami, Ichiro

    2009-01-01

    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. PMID:19553900

  15. Synthesis of ionic liquids

    DOEpatents

    Dai, Sheng (Knoxville, TN); Luo, Huimin (Knoxville, TN)

    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.

  16. Ionic liquid ethanol sensor.

    PubMed

    Lee, Yuan Gee; Chou, Tse-Chuan

    2004-07-30

    Ionic liquids containing lithium methylsulfonyl group were prepared from the precursors poly(propylene glycol)-block-(ethylene glycol)-block-(propylene glycol)-bis(2-aminopropyl ether) with different molecular weight. These liquids revealed excellent electrical conductivity in the temperature range -25 to 85 degrees C. Also, they exhibited a high boiling temperature and hence a low vapor pressure in ambient condition. Additionally, they showed a high fluidity with their viscosities being comparative with that of water. To determine the sensitivity of an ethanol sensor by using these ionic liquids, these liquids were subjected into a sequential electrochemical tests with nickel electrodes which performed a high sensitivity for the ethanol sensor. It was found that only the derivative with low molecular weight could detect ethanol. Furthermore, a linear relationship between the response current and the concentration of ethanol was constructed. The detection limit was found to be 0.13% (v/v) and its response time was 336 s. PMID:15142574

  17. Dissolving Polymers in Ionic Liquids.

    NASA Astrophysics Data System (ADS)

    Hoagland, David; Harner, John

    2009-03-01

    Dissolution and phase behavior of polymers in ionic liquids have been assessed by solution characterization techniques such as intrinsic viscosity and light scattering (static and dynamic). Elevated viscosity proved the greatest obstacle. As yet, whether principles standard to conventional polymer solutions apply to ionic liquid solutions is uncertain, especially for polymers such as polyelectrolytes and hydrophilic block copolymers that may specifically interact with ionic liquid anions or cations. For flexible polyelectrolytes (polymers releasing counterions into high dielectric solvents), characterization in ionic liquids suggests behaviors more typical of neutral polymer. Coil sizes and conformations are approximately the same as in aqueous buffer. Further, several globular proteins dissolve in a hydrophilic ionic liquid with conformations analogous to those in buffer. General principles of solubility, however, remain unclear, making predictions of which polymer dissolves in which ionic liquid difficult; several otherwise intractable polymers (e.g., cellulose, polyvinyl alcohol) dissolve and can be efficiently functionalized in ionic liquids.

  18. 3-Methylpiperidinium ionic liquids.

    PubMed

    Belhocine, Tayeb; Forsyth, Stewart A; Gunaratne, H Q Nimal; Nieuwenhuyzen, Mark; Nockemann, Peter; Puga, Alberto V; Seddon, Kenneth R; Srinivasan, Geetha; Whiston, Keith

    2015-04-28

    A wide range of room temperature ionic liquids based on the 3-methylpiperdinium cation core were produced from 3-methylpiperidine, which is a derivative of DYTEK® A amine. First, reaction with 1-bromoalkanes or 1-bromoalkoxyalkanes generated the corresponding tertiary amines (Rm?pip, R = alkyl or alkoxyalkyl); further quaternisation reactions with the appropriate methylating agents yielded the quaternary [Rmm?pip]X salts (X(-) = I(-), [CF3CO2](-) or [OTf](-); Tf = -SO2CF3), and [Rmm?pip][NTf2] were prepared by anion metathesis from the corresponding iodides. All [NTf2](-) salts are liquids at room temperature. [Rmm?pip]X (X(-) = I(-), [CF3CO2](-) or [OTf](-)) are low-melting solids when R = alkyl, but room temperature liquids upon introduction of ether functionalities on R. Neither of the 3-methylpiperdinium ionic liquids showed any signs of crystallisation, even well below 0 °C. Some related non-C-substituted piperidinium and pyrrolidinium analogues were prepared and studied for comparison. Crystal structures of 1-hexyl-1,3-dimethylpiperidinium tetraphenylborate, 1-butyl-3-methylpiperidinium bromide, 1-(2-methoxyethyl)-1-methylpiperidinium chloride and 1-(2-methoxyethyl)-1-methylpyrrolidinium bromide are reported. Extensive structural and physical data are collected and compared to literature data, with special emphasis on the systematic study of the cation ring size and/or asymmetry effects on density, viscosity and ionic conductivity, allowing general trends to be outlined. Cyclic voltammetry shows that 3-methylpiperidinium ionic liquids, similarly to azepanium, piperidinium or pyrrolidinium counterparts, are extremely electrochemically stable; the portfolio of useful alternatives for safe and high-performing electrolytes is thus greatly extended. PMID:25669485

  19. Cyclic phosphonium ionic liquids

    PubMed Central

    Mukhlall, Joshua A; Romeo, Alicia R; Gohdo, Masao; Ramati, Sharon; Berman, Marc; Suarez, Sophia N

    2014-01-01

    Summary Ionic liquids (ILs) incorporating cyclic phosphonium cations are a novel category of materials. We report here on the synthesis and characterization of four new cyclic phosphonium bis(trifluoromethylsulfonyl)amide ILs with aliphatic and aromatic pendant groups. In addition to the syntheses of these novel materials, we report on a comparison of their properties with their ammonium congeners. These exemplars are slightly less conductive and have slightly smaller self-diffusion coefficients than their cyclic ammonium congeners. PMID:24605146

  20. Low Toxic Ionic Liquids, Liquid Catanionics, and Ionic Liquid Microemulsions

    Microsoft Academic Search

    Werner Kunz; Eva Maurer; Regina Klein; Didier Touraud; Doris Rengstl; Agnes Harrar; Susanne Dengler; Oliver Zech

    2011-01-01

    In the future the demand of sustainable and low toxic surfactants and solvents will constantly increase. In this article, we present some new approaches to meet these requirements. Whereas ionic liquids are often based on imidazolium ions, we will show that there are also much less toxic ones, especially with choline as cation. Choline salts, even if solid at room

  1. Ionic liquids in confined geometries.

    PubMed

    Perkin, Susan

    2012-04-21

    Over recent years the Surface Force Apparatus (SFA) has been used to carry out model experiments revealing structural and dynamic properties of ionic liquids confined to thin films. Understanding characteristics such as confinement induced ion layering and lubrication is of primary importance to many applications of ionic liquids, from energy devices to nanoparticle dispersion. This Perspective surveys and compares SFA results from several laboratories as well as simulations and other model experiments. A coherent picture is beginning to emerge of ionic liquids as nano-structured in pores and thin films, and possessing complex dynamic properties. The article covers structure, dynamics, and colloidal forces in confined ionic liquids; ionic liquids are revealed as a class of liquids with unique and useful confinement properties and pertinent future directions of research are highlighted. PMID:22301770

  2. Ionic Liquids in Chemical Analysis

    Microsoft Academic Search

    Mihkel Koel

    2005-01-01

    Room-temperature ionic liquids are salts with a melting point close to or below room temperature. They form liquids composed in the majority of ions. This gives these materials the potential to behave very differently when they are used as solvents compared to conventional molecular liquids. The search for their application is growing in every area of analytical chemistry—electrochemistry, chromatography, electrophoresis,

  3. Anion pairs in room temperature ionic liquids predicted by molecular dynamics simulation, verified by spectroscopic characterization

    SciTech Connect

    Schwenzer, Birgit; Kerisit, Sebastien N.; Vijayakumar, M.

    2014-01-01

    Molecular-level spectroscopic analyses of an aprotic and a protic room-temperature ionic liquid, BMIM OTf and BMIM HSO4, respectively, have been carried out with the aim of verifying molecular dynamics simulations that predict anion pair formation in these fluid structures. Fourier-transform infrared spectroscopy, Raman spectroscopy and nuclear magnetic resonance spectroscopy of various nuclei support the theoretically-determined average molecular arrangements.

  4. 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.

  5. Hydrophobic ionic liquids

    DOEpatents

    Koch, Victor R. (Lincoln, MA); Nanjundiah, Chenniah (Lynn, MA); Carlin, Richard T. (Nashua, NH)

    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.

  6. Hydrophobic ionic liquids

    DOEpatents

    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.

  7. Solid-liquid interfaces of ionic liquid solutions-Interfacial layering and bulk correlations.

    PubMed

    Mezger, Markus; Roth, Roland; Schröder, Heiko; Reichert, Peter; Pontoni, Diego; Reichert, Harald

    2015-04-28

    The influence of the polar, aprotic solvent propylene carbonate on the interfacial structure of the ionic liquid (IL) 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate on sapphire was investigated by high-energy x-ray reflectivity. Experiments at solvent concentrations between 17 mol. % and 83 mol. % bridge the gap between diluted electrolytes described by the classical Gouy-Chapman theory and pure ionic liquids. Analysis of our experimental data revealed interfacial profiles comprised of alternating anion and cation enriched regions decaying gradually into the bulk liquid. With increasing solvent concentration, we observed a decrease in correlation length of the interfacial layering structure. At high ion concentrations, solvent molecules were found to accumulate laterally within the layers. By separating like-charged ions, they reduce their Coulomb repulsion. The results are compared with the bulk structure of IL/solvent blends probed by x-ray scattering and predictions from fundamental fluid theory. PMID:25933784

  8. Solid-liquid interfaces of ionic liquid solutions—Interfacial layering and bulk correlations

    NASA Astrophysics Data System (ADS)

    Mezger, Markus; Roth, Roland; Schröder, Heiko; Reichert, Peter; Pontoni, Diego; Reichert, Harald

    2015-04-01

    The influence of the polar, aprotic solvent propylene carbonate on the interfacial structure of the ionic liquid (IL) 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate on sapphire was investigated by high-energy x-ray reflectivity. Experiments at solvent concentrations between 17 mol. % and 83 mol. % bridge the gap between diluted electrolytes described by the classical Gouy-Chapman theory and pure ionic liquids. Analysis of our experimental data revealed interfacial profiles comprised of alternating anion and cation enriched regions decaying gradually into the bulk liquid. With increasing solvent concentration, we observed a decrease in correlation length of the interfacial layering structure. At high ion concentrations, solvent molecules were found to accumulate laterally within the layers. By separating like-charged ions, they reduce their Coulomb repulsion. The results are compared with the bulk structure of IL/solvent blends probed by x-ray scattering and predictions from fundamental fluid theory.

  9. Solvent-mediated molar conductivity of protic ionic liquids.

    PubMed

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

    2015-01-01

    The molar conductivity, ?m, of protic ionic liquids (PILs) in molecular solvents is measured at 298.15 K. The decrease in the ?m values of PILs is observed with an increase in the concentration of PILs. The limiting molar conductivities, ?m(0), were obtained for each PIL in different molecular solvents using a least squares method. The ?m(0) data for PILs were correlated with the structural aspects of PILs and solvent properties. The polar protic solvents show poor ionic association as compared to the polar aprotic solvents, which is discussed on the basis of the hydrogen bond donating (HBD) ability of solvents and PILs. The alkyl chain substitution of anions plays a significant role in the ionic association of the PILs. The diffusion coefficient D(0) and the transport number t were determined, which were consistent with the ?m(0) values of PILs in water. The ?m(0) and D(0) values are dependent on the hydrodynamic radius of anions of these ionic liquids. The extent of ionic association for each PIL was discussed using temperature dependent ?m data for aqueous PIL systems in terms of the Walden plot. PMID:25406387

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

    PubMed

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

    2012-03-20

    An electrochemical method based on cathodic stripping voltammetry at a gold electrode has been developed for the determination of water in ionic liquids. The technique has been applied to two aprotic ionic liquids, (1-butyl-3-ethylimidazolium tetrafluoroborate and 1-butyl-3-methylimidazolium hexafluorophosphate), and two protic ionic liquids, (bis(2-hydroxyethyl)ammonium acetate and triethylammonium acetate). When water is present in an ionic liquid, electrooxidation of a gold electrode forms gold oxides. Thus, application of an anodic potential scan or holding the potential of the electrode at a very positive value leads to accumulation of an oxide film. On applying a cathodic potential scan, a sensitive stripping peak is produced as a result of the reduction of gold oxide back to gold. The magnitude of the peak current generated from the stripping process is a function of the water concentration in an ionic liquid. The method requires no addition of reagents and can be used for the sensitive and in situ determination of water present in small volumes of ionic liquids. Importantly, the method allows the determination of water in the carboxylic acid-based ionic liquids, such as acetate-based protic ionic liquids, where the widely used Karl Fischer titration method suffering from an esterification side reaction which generates water as a side product. PMID:22372467

  11. 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.

  12. Designing Imidazole-Based Ionic Liquids and Ionic Liquid Monomers for Emerging Technologies

    Microsoft Academic Search

    Matthew D. Green; Timothy E. Long

    2009-01-01

    Imidazolium-based ionic liquids and ionic liquid monomers are becoming increasingly popular in a variety of areas including biphasic reaction catalysis, electromechanical actuator membranes and diluents, separation science membranes, and water purification agents. Ionic liquids first incorporated the imidazole ring in 1984 and this heterocyclic ring has emerged as the focal point of the ionic liquid field. Imidazole was targeted for

  13. Application of Ionic Liquids in Liquid Chromatography

    Microsoft Academic Search

    Micha? Piotr Marsza??; Roman Kaliszan

    2007-01-01

    Interest in ionic liquids (ILs) for their potential application in analytical chemistry continues to grow. Their usefulness can be due to favourable physicochemical properties, like the lack of vapour pressure, good thermal and chemical stability as well as very good dissolution properties regarding both organic and inorganic compounds. A specific feature of ILs is that these compounds provide strong proton

  14. 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

  15. Application of ionic liquids in hydrometallurgy.

    PubMed

    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

  16. 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.

  17. Effects of hydrophobic aggregation on the charge transport mechanism of quaternary ammonium ionic liquids

    NASA Astrophysics Data System (ADS)

    Griffin, Philip; Holt, Adam; Wang, Yangyang; Novikov, Vladimir; Sangoro, Joshua; Sokolov, Alexei

    2014-03-01

    Aprotic quaternary ammonium ionic liquids (ILs) are an important class of ILs due to their large electrochemical window and hydrophobicity. However, many of these ILs suffer from relatively low conductivity at room temperature which limits their use in electrochemical applications. In order to understand the nature of this low conductivity and its relation to the chemical structure of the alkyl ammonium cation, we have measured the charge transport properties and structural dynamics of the room temperature ionic liquid methyltrioctylammonium bistriflimide [m3oa][ntf2] over a broad temperature range using dielectric spectroscopy, dynamic light scattering, rheology, and pulsed field gradient nuclear magnetic resonance. We demonstrate that the low values of dc conductivity are due to the combined effects of significantly reduced ion mobility as well as reduced free ion concentration relative to other types of ILs. Secondly we find evidence for a mesoscopic scale structural relaxation process that we attribute to the reorientational motion of nanometer sized alkyl nanodomains. These two findings indicate that hydrophobic aggregation plays an important role in the charge transport mechanism of aprotic ammonium ionic liquids with long aliphatic side chains.

  18. Amphiphilic and phase-separable ionic liquids for biomass processing.

    PubMed

    Holding, Ashley J; Heikkilä, Mikko; Kilpeläinen, Ilkka; King, Alistair W T

    2014-05-01

    One main limiting factor for the technoeconomics of future bioprocesses that use ionic liquids (ILs) is the recovery of the expensive and potentially toxic IL. We have demonstrated a new series of phase-separable ionic liquids, based on the hydrophobic tetraalkylphosphonium cation ([PRRRR](+)), that can dissolve lignin in the neat state but also hemicellulose and high-purity cellulose in the form of their electrolyte solutions with dipolar aprotic solvents. For example, the IL trioctylmethylphosphonium acetate ([P8881][OAc]) was demonstrated to dissolve up to 19?wt?% of microcrystalline cellulose (MCC) at 60?°C with the addition of 40?wt?% of DMSO. It was found that the MCC saturation point is dependent on the molar ratio of DMSO and IL in solution. At the optimum saturation, a ?1:1 molar ratio of [P8881][OAc] to anhydroglucose units is observed, which demonstrates highly efficient solvation. This is attributed to the positive contribution that these more amphiphilic cation-anion pairs provide, in the context of the Lindman hypothesis. This effective dissolution is further illustrated by solution-state HSQC?NMR spectroscopy on MCC. Finally, it is also demonstrated that these electrolytes are phase separable by the addition of aqueous solutions. The addition of 10?% NaOAc solution allows a near quantitative recovery of high-purity [P8881][OAc]. However, increased volumes of aqueous solution reduced the recovery. The regenerated material was found to partially convert into the cellulose?II crystalline polymorph. PMID:24616349

  19. 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.

  20. Benzotriazole as the additive for ionic liquid lubricant: one pathway towards actual application of ionic liquids

    Microsoft Academic Search

    X. Liu; F. Zhou; Y. Liang; W. Liu

    2006-01-01

    In this paper, we report on the first tribological evaluation of the room temperature ionic liquids (RTILs) compatible lubricant additive. Benzotriazole (BTA) was chosen for study in that it shows good miscibility with imidazole ionic liquids because of similar molecular structure. BTA can greatly improve the tribological behaviors of ionic liquids carrying hexafluorophosphate anions for Steel\\/Cu–Sn alloy sliding pair mainly

  1. Quantized friction across ionic liquid thin films.

    PubMed

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

    2013-10-01

    Ionic liquids - salts in the liquid state under ambient conditions - are of great interest as precision lubricants. Ionic liquids form layered structures at surfaces, yet it is not clear how this nano-structure relates to their lubrication properties. We measured the friction force between atomically smooth solid surfaces across ionic liquid films of controlled thickness in terms of the number of ion layers. Multiple friction-load regimes emerge, each corresponding to a different number of ion layers in the film. In contrast to molecular liquids, the friction coefficients differ for each layer due to their varying composition. PMID:23942943

  2. 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.

  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. PMID:25727925

  4. Properties of Polyelectrolytes in an Ionic Liquid

    NASA Astrophysics Data System (ADS)

    Harner, John; Hoagland, David

    2008-03-01

    In solvents such as water, polyelectrolyte properties depend strongly on ionic strength, reflecting the ability of free ions to screen electrostatic interactions. At high ionic strength, polyelectrolytes remaining soluble behave similarly to neutral polymers. What happens to polyelectrolyte properties in an ionic liquid? A series of polyelectrolytes were dissolved in [EMIM][EtSO4] (ethyl-methyl-imidazolium ethylsulfate) and studied by viscometry as well as static and dynamic light scattering. Both scattering approaches show that sodium polystyrene sulfonate is more swollen in aqueous 0.1M NaBr than in [EMIM][EtSO4]. Furthermore, classical polyelectrolyte effects (fast and slow mode, increased reduced viscosity with dilution) are absent in the ionic liquid. Lastly, variably quaternized polyvinylpyridine exhibits no evidence of coil expansion as charge density increases. We conclude macroion charges are fully screened in ionic liquids.

  5. 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.

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

    PubMed

    Salminen, Eero; Virtanen, Pasi; Mikkola, Jyri-Pekka

    2014-01-01

    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 toward citronellal was achieved over a catalyst containing the alkaline ionic liquid benzalkonium methoxide. PMID:24790972

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

    PubMed Central

    Salminen, Eero; Virtanen, Pasi; Mikkola, Jyri-Pekka

    2014-01-01

    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 toward citronellal was achieved over a catalyst containing the alkaline ionic liquid benzalkonium methoxide. PMID:24790972

  8. Phosphonium-based ionic liquids and uses

    DOEpatents

    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.

  9. Peptide and micelle morphologies in ionic liquid

    NASA Astrophysics Data System (ADS)

    Montgomery, Ashley; Naik, Sandeep; Ray, Jacob; Savin, Daniel

    2010-03-01

    Ionic liquids (ILs) are considered ``green'' solvents that have shown interesting properties in polymeric solutions; however, potential screening effects in polyelectrolytes remain largely unexplored. These studies intend to compare the solution behavior of traditional polyelectrolytes like poly(styrene sulfonate) in ionic liquid and water. This will be extended into charged polypeptides such as poly(L-lysine) (PK) and PK-containing block copolymers. In particular, we are interested in the solution chain dimensions and secondary structure of the polypeptide and how it can potentially influence micelle morphologies in ionic liquids. Circular dichroism, dynamic light scattering and electron microscopy were used for characterization of peptide secondary structure and aggregate morphology respectively. The aggregation in ionic liquids will be compared with their aqueous counterparts.

  10. Zeolite synthesis in hydrated silicate ionic liquids.

    PubMed

    van Tendeloo, Leen; Haouas, Mohamed; Martens, Johan A; Kirschhock, C E A; Breynaert, Eric; Taulelle, Francis

    2015-01-01

    Hydrated alkali silicate ionic liquids (HSIL) were prepared by hydrolysis of tetraethoxysilane (TEOS) in alkali hydroxide-water mixtures, inducing coacervation and phase separation. The resulting optically clear, homogenous silicate ionic liquid offers exceptional potential for monitoring zeolite crystallisation. This enhanced synthesis route provides access to analysis of speciation, mechanistic details of zeolite formation, and brings organic-template-free zeolite synthesis by design within reach. PMID:25886652

  11. The Solubility Parameters of Ionic Liquids

    PubMed Central

    Marciniak, Andrzej

    2010-01-01

    The Hildebrand’s solubility parameters have been calculated for 18 ionic liquids from the inverse gas chromatography measurements of the activity coefficients at infinite dilution. Retention data were used for the calculation. The solubility parameters are helpful for the prediction of the solubility in the binary solvent mixtures. From the solubility parameters, the standard enthalpies of vaporization of ionic liquids were estimated. PMID:20559495

  12. Surface Nanocrystallization of an Ionic Liquid

    Microsoft Academic Search

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

    2012-01-01

    Surface crystallization at the vapor-liquid interface of the ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) is observed in synchrotron x-ray diffraction studies. Sharp Bragg reflections emerge in grazing-angle x-ray diffraction patterns 37 C above the bulk melting temperature, indicating the presence of a long-range ordered phase at the surface in coexistence with the bulk parent liquid. The unique structure of the vapor-liquid interface

  13. Ionic liquids behave as dilute electrolyte solutions

    PubMed Central

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

    2013-01-01

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

  14. Ionic liquids behave as dilute electrolyte solutions.

    PubMed

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

    2013-06-11

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

  15. Water Contaminant Mitigation in Ionic Liquid Propellant

    NASA Technical Reports Server (NTRS)

    Conroy, David; Ziemer, John

    2009-01-01

    Appropriate system and operational requirements are needed in order to ensure mission success without unnecessary cost. Purity requirements applied to thruster propellants may flow down to materials and operations as well as the propellant preparation itself. Colloid electrospray thrusters function by applying a large potential to a room temperature liquid propellant (such as an ionic liquid), inducing formation of a Taylor cone. Ions and droplets are ejected from the Taylor cone and accelerated through a strong electric field. Electrospray thrusters are highly efficient, precise, scaleable, and demonstrate low thrust noise. Ionic liquid propellants have excellent properties for use as electrospray propellants, but can be hampered by impurities, owing to their solvent capabilities. Of foremost concern is the water content, which can result from exposure to atmosphere. Even hydrophobic ionic liquids have been shown to absorb water from the air. In order to mitigate the risks of bubble formation in feed systems caused by water content of the ionic liquid propellant, physical properties of the ionic liquid EMI-Im are analyzed. The effects of surface tension, material wetting, physisorption, and geometric details of the flow manifold and electrospray emitters are explored. Results are compared to laboratory test data.

  16. Surface Nanocrystallization of an Ionic Liquid

    SciTech Connect

    Jeon, Yoonnam; Vaknin, David; Bu, Wei; Sung, Jaeho; Ouchi, Yukio; Sung, Woongmo; Kim, Doseok (Iowa State); (Nagoya); (Sogang)

    2012-03-26

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

  17. Surface nanocrystallization of an ionic liquid.

    PubMed

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

    2012-02-01

    Surface crystallization at the vapor-liquid interface of the ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) is observed in synchrotron x-ray diffraction studies. Sharp Bragg reflections emerge in grazing-angle x-ray diffraction patterns 37?°C above the bulk melting temperature, indicating the presence of a long-range ordered phase at the surface in coexistence with the bulk parent liquid. The unique structure of the vapor-liquid interface where butyl chains attached to the cations are expelled to the vapor side facilitates interionic electrostatic interactions that lead to the crystallization. Our results demonstrate the complexity of ionic-liquid structure with their tendency to spontaneously phase separate into nanodomains with finite correlation lengths in coexistence with the liquid phase. By virtue of interfacial boundary conditions, these nanodomains grow laterally to form quasi-two-dimensional crystals. PMID:22400939

  18. Surface Nanocrystallization of an Ionic Liquid

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

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

  19. Understanding the polarity of ionic liquids.

    PubMed

    Ab Rani, M A; Brant, A; Crowhurst, L; Dolan, A; Lui, M; Hassan, N H; Hallett, J P; Hunt, P A; Niedermeyer, H; Perez-Arlandis, J M; Schrems, M; Welton, T; Wilding, R

    2011-10-01

    The polarities of a wide range of ionic liquids have been determined using the Kamlet-Taft empirical polarity scales ?, ? and ?*, with the dye set Reichardt's Dye, N,N-diethyl-4-nitroaniline and 4-nitroaniline. These have been compared to measurements of these parameters with different dye sets and to different polarity scales. The results emphasise the importance of recognising the role that the nature of the solute plays in determining these scales. It is particularly noted that polarity scales based upon charged solutes can give very different values for the polarity of ionic liquids compared to those based upon neutral probes. Finally, the effects of commonplace impurities in ionic liquids are reported. PMID:21858359

  20. Interactions of ionic liquids and water.

    PubMed

    Ficke, Lindsay E; Brennecke, Joan F

    2010-08-19

    Experimental excess enthalpies of ionic liquid and water mixtures in combination with calculated CHELPG atomic charges were used to investigate the interactions between the species in solution. The excess enthalpies of ionic liquids in water were obtained by calorimetry, using a Setaram C80 calorimeter, including temperatures from (313.15 to 348.15) K and the entire range of composition. The ionic liquids investigated all contain the 1-ethyl-3-methylimidazolium cation except one, which has an added hydroxyl group on the cation (1-(2-hydroxyethyl)-3-methylimidazolium cation). The anions investigated are ethylsulfate, methylsulfate, hydrogensulfate, trifluoromethanesulfonate, methanesulfonate, and trifluoroacetate, and these will demonstrate the effect of systematically varying the substituents on the anion. The CHELPG atomic charges on the cations and anions were calculated using the Gaussian 03 program. The CHELPG atomic charges are consistent with the observed trends in excess enthalpy and provide insight into cation/water, anion/water, and cation/anion interactions. PMID:20701381

  1. 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.

  2. Ionic liquids as active pharmaceutical ingredients.

    PubMed

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

    2011-06-01

    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. PMID:21557480

  3. Unravelling nanoconfined films of ionic liquids.

    PubMed

    Lee, Alpha A; Vella, Dominic; Perkin, Susan; Goriely, Alain

    2014-09-01

    The confinement of an ionic liquid between charged solid surfaces is treated using an exactly solvable 1D Coulomb gas model. The theory highlights the importance of two dimensionless parameters: the fugacity of the ionic liquid, and the electrostatic interaction energy of ions at closest approach, in determining how the disjoining pressure exerted on the walls depends on the geometrical confinement. Our theory reveals that thermodynamic fluctuations play a vital role in the "squeezing out" of charged layers as the confinement is increased. The model shows good qualitative agreement with previous experimental data, with all parameters independently estimated without fitting. PMID:25194391

  4. 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(trihexyl)phosphonium dicyanamide as the RTIL. It was determined that it has good absorption properties for methanol and ?-pinene, is thermally stable, and is relatively easy to synthesize. It has a density of 0.89 g/mL at 20°C and a molecular weight of 549.9 g/mol. Trials were conducted with a small absorption system and a larger absorption system. Methanol, formaldehyde, and other HAPs were absorbed well, nearly 100%. Acetaldehyde was difficult to capture. Total VOC capture, while satisfactory on methanol and ?-pinene in a lab system, was less than expected in the field, 60-80%. The inability to capture the broad spectrum of total organics is likely due to difficulties in cleaning them from the ionic liquid rather than the ability of the ionic liquid to absorb. It’s likely that a commercial system could be constructed to remove 90 to 100% of the gas contaminates. Selecting the correct ionic liquid would be key to this. Absorption may not be the main selection criterion, but rather how easily the ionic liquid can be cleaned is very important. The ionic liquid absorption system might work very well in a system with a limited spectrum of pollutants, such as a paint spray line, where there are not very high molecular weight, non volatile, compounds in the exhaust.

  5. Thermal properties of imidazolium ionic liquids

    Microsoft Academic Search

    Helen L Ngo; Karen LeCompte; Liesl Hargens; Alan B McEwen

    2000-01-01

    We investigated the thermal properties of several imidazolium salts using DSC and TGA\\/SDTA data. Many of these salts are liquids at sub-ambient temperatures. These ionic liquids form glasses at low temperatures and have minimal vapor pressure up to their thermal decomposition temperature (>400°C). Thermal decomposition is endothermic with the inorganic anions and exothermic with the organic anions investigated. Halide anions

  6. 1,2,3-triazolium ionic liquids

    DOEpatents

    Luebke, David; Nulwala, Hunaid; Tang, Chau

    2014-12-09

    The present invention relates to compositions of matter that are ionic liquids, the compositions comprising substituted 1,2,3-triazolium cations combined with any anion. Compositions of the invention should be useful in the separation of gases and, perhaps, as catalysts for many reactions.

  7. Esterification of Starch in Ionic Liquids

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  8. Ionic liquids as additives for thermoplastics

    Microsoft Academic Search

    K. I. Park; M. Xanthos

    2007-01-01

    In attempts to develop new process modifiers for thermoplastics, two ionic liquids with long chain hydrophobic cations and different anions were introduced in a biodegradable polymer. Methods of incorporation included melt blending, solvent casting and microencapsulation from w\\/o\\/w systems at concentrations up to 10 wt%. The modified polymers were characterized rheologically and by TGA to determine process and thermal stability,

  9. Energy Efficient Electrochromic Windows Incorporating Ionic Liquids

    Microsoft Academic Search

    Cheri Boykin; James Finley; Donald Anthony; Julianna Knowles; Richard Markovic; Michael Buchanan; Mary Ann Fuhry; Lisa Perrine

    2008-01-01

    One approach to increasing the energy efficiency of windows is to control the amount of solar radiation transmitted through a window by using electrochromic technology. What is unique about this project is that the electrochromic is based on the reduction\\/oxidation reactions of cathodic and anodic organic semi-conducting polymers using room temperature ionic liquids as ion transport electrolytes. It is believed

  10. Nanostructure-thermal conductivity relationships in protic ionic liquids.

    PubMed

    Murphy, Thomas; Varela, Luis M; Webber, Grant B; Warr, Gregory G; Atkin, Rob

    2014-10-16

    The thermal conductivities of nine protic ionic liquids (ILs) have been investigated between 293 and 340 K. Within this range, the thermal conductivities are between 0.18 and 0.30 W · m(-1) · K(-1). These values are higher than those typically associated with oils and aprotic ILs, but lower than those of strongly hydrogen bonding solvents like water. Weak linear decreases in thermal conductivity with temperature are noted, with the exception of ethanolammonium nitrate (EtAN) where the thermal conductivity increases with temperature. The dependence of thermal conductivity on IL type is analyzed with use of the Bahe-Varela pseudolattice theory. This theory treats the bulk IL as an array of ordered domains with intervening domains of uncorrelated structure which enable and provide barriers to heat propagation (respectively) via allowed vibrational modes. For the protic ILs investigated, thermal conductivity depends strongly on the IL cation alkyl chain length. This is because the cation alkyl chain controls the dimensions of the IL bulk nanostructure, which consists of charged (ordered domains) and uncharged regions (disordered domains). As the cation alkyl chain controls the dimensions of the disordered domains, it thus limits the thermal conductivity. To test the generality of this interpretation, the thermal conductivities of propylammonium nitrate (PAN) and PAN-octanol mixtures were examined; water selectively swells the PAN charged domain, while octanol swells the uncharged regions. Up to a certain concentration, adding water increases thermal conduction and octanol decreases it, as expected. However, at high solute concentrations the IL nanostructure is broken. When additional solvent is added above this concentration the rate of change in thermal conductivity is greatly reduced. This is because, in the absence of nanostructure, the added solvent only serves to dilute the salt solution. PMID:25229992

  11. INNOVATIVE APPLICATIONS OF IONIC LIQUIDS AS “GREEN” ENGINEERING LIQUIDS

    Microsoft Academic Search

    Hua Zhao

    2006-01-01

    Over the past decade, ionic liquids (ILs) have become one of the fastest growing “green” media for chemists and engineers due to their superb physicochemical properties. The applications of these remarkable salts in reactions and extraction processes have been extensively investigated and reviewed. This review, however, highlights recent advances of ILs as versatile “green” engineering liquids in a variety of

  12. Miscibility of ionic liquids with polyhydric alcohols.

    PubMed

    Makowska, Anna; Dyoniziak, Ewa; Siporska, Agnieszka; Szyd?owski, Jerzy

    2010-02-25

    Liquid-liquid miscibility temperatures as a function of composition have been determined experimentally for the binary systems formed by ionic liquids ([bmim][BF(4)], [bmim][PF(6)], [emim][Tf(2)N], [bmim][Tf(2)N], [hmim][Tf(2)N]) and polyhydric alcohols (1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2,3-propanetriol, 1,2-butanediol). The impact of ionic liquid and di- or three-hydroxy alcohol characteristics focusing on the effect of the IL's anion nature, cation alkyl chain length, and alcohol structure (number of hydroxyl groups, position of the hydroxy groups in the molecule, and number of carbon atoms in the diols) is presented. It appears that all systems exhibit upper critical solution temperatures. For dihydroxy alcohols mentioned above, miscibility with 1-butyl-3-methylimidazolium ionic liquids follows the order [BF(4)](-) > [Tf(2)N](-) > [PF(6)](-) and is dependent on the hydrogen-bond basicity of the anion. Analysis of these findings leads us to conclude that the miscibility of ionic liquids is likely related to the hydrogen-bond acceptor strength of the anion. Comparing the miscibility of 1,2-ethanediol with 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imides, it can be seen that surprisingly, T(c)([emim](+)) < T(c)([bmim](+)) < T(c)([hmim](+)). This arrangement of critical temperatures is opposite to that observed earlier for systems with monohydroxy alcohols. Analyzing the influence of the polyhydroxy alcohol structure, we also noticed that the miscibility of the polyhydroxy alcohols with [bmim][Tf(2)N] or [bmim][BF(4)] decreases when the polarity of the alcohol rises. PMID:20095595

  13. Preparation of cellulose-based ionic porous material compatibilized with polymeric ionic liquid

    Microsoft Academic Search

    Kamalesh Prasad; Shozaburo Mine; Yoshiro Kaneko; Jun-ichi Kadokawa

    2010-01-01

    Cellulose-based ionic porous material compatibilized with polymeric ionic liquid was prepared by means of templating technique\\u000a using oil\\/ionic liquid emulsion in the presence of sorbitane monooleate. In situ polymerization of a mixture of polymerizable\\u000a ionic liquids, 1-(3-acryloyloxypropyl)-3-methylimidazolium and 1-(3-acryloyloxypropyl)-3-vinylimidazolium bromides was first\\u000a performed in a solution of cellulose in a solvent of an ionic liquid, 1-butyl-3-methylimidazolium chloride. The sonication\\u000a of

  14. Pseudocapacitive mechanism of manganese oxide in 1-ethyl-3-methylimidazolium thiocyanate ionic liquid electrolyte studied using X-ray photoelectron spectroscopy.

    PubMed

    Chang, Jeng-Kuei; Lee, Ming-Tsung; Tsai, Wen-Ta; Deng, Ming-Jay; Cheng, Hui-Fang; Sun, I-Wen

    2009-10-01

    The electrochemical behavior of anodically deposited manganese oxide was studied in pyrrolidinium formate (P-HCOO), 1-butyl-3-methylimidazolium hexafluorophosphate (BMI-PF6), and 1-ethyl-3-methylimidazolium thiocyanate (EMI-SCN) ionic liquids (ILs). The experimental data indicate that the Mn oxide electrode showed ideal pseudocapacitive performance in aprotic EMI-SCN IL. In a potential window of approximately 1.5 V, the oxide specific capacitance, evaluated using cyclic voltammetry and chronopotentiometry, was about 55 F/g. The electrochemical energy storage reaction was examined using X-ray photoelectron spectroscopy (XPS). It was confirmed that the SCN- anions, instead of the EMI+ cations, were the primary working species that can become incorporated into the oxide and thus compensate the Mn3+/Mn4+ valent state variation upon the charge-discharge process. According to the analytical results, a pseudocapacitive mechanism of Mn oxide in the SCN- based aprotic IL was proposed. PMID:19621902

  15. USING CARBON DIOXIDE AND IONIC LIQUIDS FOR ABSORPTION REFRIGERATION

    Microsoft Academic Search

    MIHIR SEN; SAMUEL PAOLUCCI

    The use of a new set of compounds, known as ionic liquids, is proposed for applications in thermal engineering. Ionic liquids are organic salts that are liquid at room temperature. They have certain properties that make them friendly to the environment: they do not evaporate, they are not toxic, and they are stable as liquids over a very wide temperature

  16. Dissolution enthalpies of cellulose in ionic liquids.

    PubMed

    Parviainen, Helena; Parviainen, Arno; Virtanen, Tommi; Kilpeläinen, Ilkka; Ahvenainen, Patrik; Serimaa, Ritva; Grönqvist, Stina; Maloney, Thaddeus; Maunu, Sirkka Liisa

    2014-11-26

    In this work, interactions between cellulose and ionic liquids were studied calorimetrically and by optical microscopy. Two novel ionic liquids (1,5-Diazabicyclo[4.3.0]non-5-enium propionate and N-methyl-1,5-diazabicyclo[4.3.0]non-5-enium dimethyl phosphate) and 1-ethyl-3-methylimidazolium acetate-water mixtures were used as solvents. Optical microscopy served in finding the extent of dissolution and identifying the dissolution pattern of the cellulose sample. Calorimetric studies identified a peak relating to dissolution of cellulose in solvent. The transition did, however, not indicate complete dissolution, but rather dissolution inside fibre or fibrils. This method was used to study differences between four cellulose samples with different pretreatment or origins. PMID:25256460

  17. Ionic Liquid Membranes for Carbon Dioxide Separation

    SciTech Connect

    Myers, C.R.; Ilconich, J.B.; Luebke, D.R.; Pennline, H.W.

    2008-07-12

    Recent scientific studies are rapidly advancing novel technological improvements and engineering developments that demonstrate the ability to minimize, eliminate, or facilitate the removal of various contaminants and green house gas emissions in power generation. The Integrated Gasification Combined Cycle (IGCC) shows promise for carbon dioxide mitigation not only because of its higher efficiency as compared to conventional coal firing plants, but also due to a higher driving force in the form of high partial pressure. One of the novel technological concepts currently being developed and investigated is membranes for carbon dioxide (CO2) separation, due to simplicity and ease of scaling. A challenge in using membranes for CO2 capture in IGCC is the possibility of failure at elevated temperatures or pressures. Our earlier research studies examined the use of ionic liquids on various supports for CO2 separation over the temperature range, 37°C-300°C. The ionic liquid, 1-hexyl-3methylimidazolium Bis(trifluoromethylsulfonyl)imide, ([hmim][Tf2N]), was chosen for our initial studies with the following supports: polysulfone (PSF), poly(ether sulfone) (PES), and cross-linked nylon. The PSF and PES supports had similar performance at room temperature, but increasing temperature caused the supported membranes to fail. The ionic liquid with the PES support greatly affected the glass transition temperature, while with the PSF, the glass transition temperature was only slightly depressed. The cross-linked nylon support maintained performance without degradation over the temperature range 37-300°C with respect to its permeability and selectivity. However, while the cross-linked nylon support was able to withstand temperatures, the permeability continued to increase and the selectivity decreased with increasing temperature. Our studies indicated that further testing should examine the use of other ionic liquids, including those that form chemical complexes with CO2 based on amine interactions. The hypothesis is that the performance at the elevated temperatures could be improved by allowing a facilitated transport mechanism to become dominant. Several amine-based ionic liquids were tested on the cross-linked nylon support. It was found that using the amine-based ionic liquid did improve selectivity and permeability at higher temperature. The hypothesis was confirmed, and it was determined that the type of amine used also played a role in facilitated transport. Given the appropriate aminated ionic liquid with the cross-linked nylon support, it is possible to have a membrane capable of separating CO2 at IGCC conditions. With this being the case, the research has expanded to include separation of other constituents besides CO2 (CO, H2S, etc.) and if they play a role in membrane poisoning or degradation. This communication will discuss the operation of the recently fabricated ionic liquid membranes and the impact of gaseous components other than CO2 on their performance and stability.

  18. Ionic Liquids and Supercritical Co 2

    Microsoft Academic Search

    Lynnette A. Blanchard; Zhiyong Gu; Joan F. Brennecke; Eric J. Beckman

    \\u000a Although ionic liquids (ILs) are organic solvents, They exhibit vanishing small vapour pressures [1,2]. Negligible volatility means that the most prevalent route for escape to the atmosphere and also exposure to workers — evaporation\\u000a — is absent. Low vapour pressure may also renders these solvents safer, as flash points will be much higher than for traditional\\u000a organic solvents. The development

  19. Equation of state for ionic liquids

    Microsoft Academic Search

    V. B. Rogankov

    2009-01-01

    A simple form of equation of state for ionic liquids is proposed as an asymptotic low-temperature variant of the fluctuational\\u000a equation of state developed by author. This function predicts reliably the properties of the pure substances and mixtures\\u000a with the quite different molecular structures in the wide temperature- and pressure-ranges including the critical region.\\u000a It is essentially important at evaluation,

  20. Insight into the cosolvent effect of cellulose dissolution in imidazolium-based ionic liquid systems.

    PubMed

    Zhao, Yuling; Liu, Xiaomin; Wang, Jianji; Zhang, Suojiang

    2013-08-01

    Recently, it has been reported that addition of a cosolvent significantly influences solubility of cellulose in ionic liquids (ILs), but little is known about the influence mechanism of the cosolvent on the molecular level. In this work, four kinds of typical molecular solvents (dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), CH?OH, and H?O) were used to investigate the effect of cosolvents on cellulose dissolution in [C?mim][CH?COO] by molecular dynamics simulations and quantum chemistry calculations. It was found that dissolution of cellulose in IL/cosolvent systems is mainly determined by the hydrogen bond interactions between [CH?COO](-) anions and the hydroxyl protons of cellulose. The effect of cosolvents on the solubility of cellulose is indirectly achieved by influencing such hydrogen bond interactions. The strong preferential solvation of [CH?COO](-) by the protic solvents (CH?OH and H?O) can compete with the cellulose-[CH?COO](-) interaction in the dissolution process, resulting in decreased cellulose solubility. On the other hand, the aprotic solvents (DMSO and DMF) can partially break down the ionic association of [C?mim][CH?COO] by solvation of the cation and anion, but no preferential solvation was observed. The dissociated [CH?COO](-) would readily interact with cellulose to improve the dissolution of cellulose. Furthermore, the effect of the aprotic solvent-to-IL molar ratio on the dissolution of cellulose in [C?mim][CH?COO]/DMSO systems was investigated, and a possible mechanism is proposed. These simulation results provide insight into how a cosolvent affects the dissolution of cellulose in ILs and may motivate further experimental studies in related fields. PMID:23829272

  1. Study of Wear and Corrosion Properties of Coated Ionic Liquid

    Microsoft Academic Search

    Zhang Xiaohao; Zhang Xiangjun; Liu Yonghe; Mikhail Kosinsky; Imad Ahmed; Stefan Krischok; Juergen A. Schaefer

    \\u000a In this paper, in order to weaken the corrosion property of ionic liquids and use it as vacuum lubricant, we coated the ionic\\u000a liquids with some other liquid and tested their friction and corrosion properties using microtribometer and scanning electron\\u000a microscope (SEM). The result is gratifying. Compared to the pure ionic liquid, most of the coated samples had a one

  2. Wetting and tribological properties of ionic liquids.

    PubMed

    Castejón, Henry J; Wynn, Troy J; Marcin, Zachary M

    2014-04-01

    A phenomenological study of the surface-wetting and tribological properties of various ionic liquids was conducted using molecular dynamics simulations. The surface-wetting capabilities of the liquids were studied by simulating the morphological transformation of an isolated liquid drop in vacuum to its equilibrium state on solid surface. The tribological properties of the liquids were probed examining their flow behaviors and viscosities in computational lubrication experiments. All liquids exhibited good surface-wetting properties, as demonstrated by the hemispherical shape of the droplets at equilibrium and the surface contact angles. Contact angles for all liquids were much lower than 90°. Lubrication experiments demonstrated a flow behavior for the liquids that depended on the magnitude of the applied shear rate. Three distinctive flow regimes were observed: Newtonian, thixotropic (non-Newtonian), and oversheared. The liquids' viscosities were determined in the Newtonian regime and agree well with experimental results and with previously reported values calculated using equilibrium simulations. The phenomenological approach implemented in this study allowed for the calculation of the transport properties of the liquids and produced values within the appropriate order of magnitude without the use of calculational artifacts. These results corroborate previous reports indicating that nonequilibrium techniques represent a more robust approach for the calculation of transport properties than do equilibrium methods based on time-correlation functions. PMID:24641326

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

    DOEpatents

    Li, Zaiwei (Moreno Valley, CA); Tang, Yongchun (Walnut, CA); Cheng; Jihong (Arcadia, CA)

    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.

  4. Ionic liquid electrolytes for dye-sensitized solar cells.

    PubMed

    Gorlov, Mikhail; Kloo, Lars

    2008-05-28

    The potential of room-temperature molten salts (ionic liquids) as solvents for electrolytes for dye-sensitized solar cells has been investigated during the last decade. The non-volatility, good solvent properties and high electrochemical stability of ionic liquids make them attractive solvents in contrast to volatile organic solvents. Despite this, the relatively high viscosity of ionic liquids leads to mass-transport limitations. Here we review recent developments in the application of different ionic liquids as solvents or components of liquid and quasi-solid electrolytes for dye-sensitized solar cells. PMID:18688394

  5. Thermo-Rheometric Studies of New Class Ionic Liquid Lubricants

    Microsoft Academic Search

    Sayavur Bakhtiyarov; Daniel Scheiman; Alan van Dyke

    2010-01-01

    Due to their specific properties, such as small volatility, nonflammability, extreme thermal stability, low melting point, wide liquid range, and good miscibility with organic materials, ionic liquids attracted particular interest in various industrial processes. Recently, the unique properties of ionic liquids caught the attention of space tribologists. The traditional lubricating materials used in space have limited lifetimes in vacuum due

  6. A morpholinium ionic liquid for cellulose dissolution.

    PubMed

    Raut, Dilip G; Sundman, Ola; Su, Weiqing; Virtanen, Pasi; Sugano, Yasuhito; Kordas, Krisztian; Mikkola, Jyri-Pekka

    2015-10-01

    A series of substituted morpholinium ionic salts and allyl ammonium acetates were prepared. Amongst those, N-allyl-N-methylmorpholinium acetate ([AMMorp][OAc]) was found to dissolve cellulose readily without any pre-processing of native cellulose. At 120°C, [AMMorp][OAc] could dissolve 30wt%, 28wt% and 25wt% of cellulose with degree of polymerization (DPn) - 789, 1644 and 2082 respectively, in 20min. Importantly, SEC analysis indicated that no discernible changes occurred in terms of the degree of polymerization of the different celluloses after regeneration. Furthermore, when comparing the cellulose dissolution capability of these newly synthesized ionic liquids, it is evident that the combination of all three constituents - the morpholinium cation, the existence of an allyl group and choosing the acetate anion are essential for efficient cellulose dissolution. The structure and morphology of the regenerated cellulosic materials were characterized by SEM, XRD, TGA, CP/MAS (13)C NMR and FTIR, respectively. PMID:26076596

  7. Homopolymer Dissolution in a Hydrophilic Ionic Liquid

    NASA Astrophysics Data System (ADS)

    Hoagland, David; Harner, John

    2010-03-01

    Dissolution, structure, and dynamics of both neutral and charged polymers dissolved in a hydrophilic room temperature ionic liquid (IL), ethylmethylimidazolium ethyl sulfate [EMIM][EtSO4], have been studied by classical physicochemical methods (static and dynamic light scattering, intrinsic viscosity, refractometry) to determine differences in solution behavior from conventional aqueous and organic solvents. This IL is water miscible. Many neutral polymers and charged polymer salts molecularly dissolve, although solubility doesn't correlate with polymer hydrophilicity. Model neutral soluble polymers are polyvinylpyrrolidone and hydroroxyethyl cellulose while sodium poly(styrene sulfonate) and the iodo salt of methyl-quaternized poly(vinyl pyridine) fill the same role for charged polymers. The latter display none of the polyelectrolyte effects found in low ionic strength water, consistent with strong electrostatic screening in IL. In virial coefficient and coil size, the IL acts for these neutral and charged polymers as a classical good solvent. (Support: UMass MRSEC)

  8. Tribochemical Reaction of Ionic Liquids on Sliding Metal Surfaces

    Microsoft Academic Search

    Tsutomu Yagi; Shinya Sasaki; Hiroki Mano; Koji Miyake; Miki Nakano; Takao Ishida

    \\u000a Ionic liquids are expected as lubricants under a vacuum condition, because of their low vapor pressure. We carried out high\\u000a vacuum pin-on-disc sliding tests to find out tlie effect of sliding materials (Fe, AI, Cu, Ti, etc.) on tribological properties\\u000a and decomposition of ionic liquids. Ionic liquids provided low friction coefficients for all metals. Rises of some partial\\u000a pressures were

  9. Factors Influencing Electrochemical Actuation of Polyaniline Fibers in Ionic Liquids

    Microsoft Academic Search

    Wen Lu; Benjamin R. Mattes

    2005-01-01

    Room-temperature ionic liquids have been demonstrated to be advantageous in the development of conducting polymer electrochemical devices. In this paper, we fabricated electrochemical actuators using polyaniline fibers and ionic liquid electrolytes and investigated factors that influence their actuation performance in the ionic liquid [BMIM][BF4], such as the dopant anion, conductive and mechanical properties of the polyaniline fibers, external load, and

  10. Zwitterionic Polymersomes in an Ionic Liquid: Room Temperature TEM Characterization

    E-print Network

    Tew, Gregory N.

    Zwitterionic Polymersomes in an Ionic Liquid: Room Temperature TEM Characterization Raghavendra R)- dimethylammonium methanesulfonate (see Figure 1). Polymer vesicles, also known as "polymersomes", have attracted

  11. Electrotunable Lubricity with Ionic Liquid Nanoscale Films

    NASA Astrophysics Data System (ADS)

    Fajardo, O. Y.; Bresme, F.; Kornyshev, A. A.; Urbakh, M.

    2015-01-01

    One of the main challenges in tribology is finding the way for an in situ control of friction without changing the lubricant. One of the ways for such control is via the application of electric fields. In this respect a promising new class of lubricants is ionic liquids, which are solvent-free electrolytes, and their properties should be most strongly affected by applied voltage. Based on a minimal physical model, our study elucidates the connection between the voltage effect on the structure of the ionic liquid layers and their lubricating properties. It reveals two mechanisms of variation of the friction force with the surface charge density, consistent with recent AFM measurements, namely via the (i) charge effect on normal and in-plane ordering in the film and (ii) swapping between anion and cation layers at the surfaces. We formulate conditions that would warrant low friction coefficients and prevent wear by resisting ``squeezing-out'' of the liquid under compression. These results give a background for controllable variation of friction.

  12. Electrotunable Lubricity with Ionic Liquid Nanoscale Films

    PubMed Central

    Fajardo, O. Y.; Bresme, F.; Kornyshev, A. A.; Urbakh, M.

    2015-01-01

    One of the main challenges in tribology is finding the way for an in situ control of friction without changing the lubricant. One of the ways for such control is via the application of electric fields. In this respect a promising new class of lubricants is ionic liquids, which are solvent-free electrolytes, and their properties should be most strongly affected by applied voltage. Based on a minimal physical model, our study elucidates the connection between the voltage effect on the structure of the ionic liquid layers and their lubricating properties. It reveals two mechanisms of variation of the friction force with the surface charge density, consistent with recent AFM measurements, namely via the (i) charge effect on normal and in-plane ordering in the film and (ii) swapping between anion and cation layers at the surfaces. We formulate conditions that would warrant low friction coefficients and prevent wear by resisting “squeezing-out” of the liquid under compression. These results give a background for controllable variation of friction. PMID:25572127

  13. Electrotunable lubricity with ionic liquid nanoscale films.

    PubMed

    Fajardo, O Y; Bresme, F; Kornyshev, A A; Urbakh, M

    2015-01-01

    One of the main challenges in tribology is finding the way for an in situ control of friction without changing the lubricant. One of the ways for such control is via the application of electric fields. In this respect a promising new class of lubricants is ionic liquids, which are solvent-free electrolytes, and their properties should be most strongly affected by applied voltage. Based on a minimal physical model, our study elucidates the connection between the voltage effect on the structure of the ionic liquid layers and their lubricating properties. It reveals two mechanisms of variation of the friction force with the surface charge density, consistent with recent AFM measurements, namely via the (i) charge effect on normal and in-plane ordering in the film and (ii) swapping between anion and cation layers at the surfaces. We formulate conditions that would warrant low friction coefficients and prevent wear by resisting "squeezing-out" of the liquid under compression. These results give a background for controllable variation of friction. PMID:25572127

  14. Durable electrooptic devices comprising ionic liquids

    DOEpatents

    Agrawal, Anoop (Tucson, AZ); Cronin, John P. (Tucson, AZ); Tonazzi, Juan C. L. (Tucson, AZ); Warner, Benjamin P. (Los Alamos, NM); McCleskey, T. Mark (Los Alamos, NM); Burrell, Anthony K. (Los Alamos, NM)

    2005-11-01

    Electrolyte solutions for electrochromic devices such as rear view mirrors and displays with low leakage currents are prepared using inexpensive, low conductivity conductors. Preferred electrolytes include bifunctional redox dyes and molten salt solvents with enhanced stability toward ultraviolet radiation. The solvents include lithium or quaternary ammonium cations, and perfluorinated sulfonylimide anions selected from trifluoromethylsulfonate (CF3SO3-), bis(trifluoromethylsulfonyl)imide ((CF3SO2)2N-), bis(perfluoroethylsulfonyl)imide ((CF3CF2SO2)2N-) and tris(trifluoromethylsulfonyl)methide ((CF3SO2)3C-). Electroluminescent, electrochromic and photoelectrochromic devices with nanostructured electrodes include ionic liquids with bifunctional redox dyes.

  15. Properties of Water Confined in Ionic Liquids

    PubMed Central

    Saihara, Koji; Yoshimura, Yukihiro; Ohta, Soichi; Shimizu, Akio

    2015-01-01

    The varying states of water confined in the nano-domain structures of typical room temperature ionic liquids (ILs) were investigated by 1H NMR and by measurements of self-diffusion coefficients while systematically varying the IL cations and anions. The NMR peaks for water in BF4-based ILs were clearly split, indicating the presence of two discrete states of confined water (H2O and HOD). Proton and/or deuterium exchange rate among the water molecules was very slowly in the water-pocket. Notably, no significant changes were observed in the chemical shifts of the ILs. Self-diffusion coefficient results showed that water molecules exhibit a similar degree of mobility, although their diffusion rate is one order of magnitude faster than that of the IL cations and anions. These findings provide information on a completely new type of confinement, that of liquid water in soft matter. PMID:26024339

  16. Properties of water confined in ionic liquids.

    PubMed

    Saihara, Koji; Yoshimura, Yukihiro; Ohta, Soichi; Shimizu, Akio

    2015-01-01

    The varying states of water confined in the nano-domain structures of typical room temperature ionic liquids (ILs) were investigated by (1)H NMR and by measurements of self-diffusion coefficients while systematically varying the IL cations and anions. The NMR peaks for water in BF4-based ILs were clearly split, indicating the presence of two discrete states of confined water (H2O and HOD). Proton and/or deuterium exchange rate among the water molecules was very slowly in the water-pocket. Notably, no significant changes were observed in the chemical shifts of the ILs. Self-diffusion coefficient results showed that water molecules exhibit a similar degree of mobility, although their diffusion rate is one order of magnitude faster than that of the IL cations and anions. These findings provide information on a completely new type of confinement, that of liquid water in soft matter. PMID:26024339

  17. Vapor–liquid equilibria of ammonia + ionic liquid mixtures

    Microsoft Academic Search

    A. Yokozeki; Mark B. Shiflett

    2007-01-01

    Solubilities of ammonia in room-temperature ionic liquids, 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium thiocyanate, 1-ethyl-3-methylimidazolium ethylsulfate, and N,N-dimethylethanolammonium acetate have been measured for the first time. Static phase equilibrium cells used in our previous work have been slightly modified for the present solubility measurements. Six mixture compositions of each binary system were prepared for the present experiments from about 30 to 85mol% of

  18. Toxicity of ionic liquids prepared from biomaterials.

    PubMed

    Gouveia, W; Jorge, T F; Martins, S; Meireles, M; Carolino, M; Cruz, C; Almeida, T V; Araújo, M E M

    2014-06-01

    In search of environmentally-friendly ionic liquids (ILs), 14 were prepared based on the imidazolium, pyridinium and choline cations, with bromide and several amino acids as anions. Good yields were obtained in the synthesis of pyridinium ILs and those prepared from choline and amino acids. Four of the ILs synthesized from choline and the amino acids arginine, glutamine, glutamic acid and cystine are described here for the first time. The toxicity of the synthesized ILs was checked against organisms of various levels of organization: the crustacean Artemia salina; Human cell HeLa (cervical carcinoma); and bacteria with different types of cell wall, Bacillus subtilis and Escherichia coli. The toxicity was observed to depend on both the cation and anion. Choline-amino acid ILs showed a remarkable low toxicity to A. salina and HeLa cell culture, ten times less than imidazolium and pyridinium ILs. None of ionic liquids exhibited marked toxicity to bacteria, and the effect was 2-3 orders of magnitude smaller than that of the antibiotic chloramphenicol. PMID:24268343

  19. 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.

  20. Kinetics and Thermodynamics of Hydrogen Oxidation and Oxygen Reduction in Hydrophobic Room-Temperature Ionic Liquids

    PubMed Central

    Rollins, Julie B.; Conboy, John C.

    2010-01-01

    In this study 1-dodecyl-3-methylimidazolium (C12mim) bis(pentafluoroethylsulfonyl)imide (BETI) and 1-dodecylimidazolium (C12im) BETI hydrophobic room-temperature ionic liquids (RTILs) were synthesized and used as proton-conducting electrolytes in a nonhumidified feed gas electrochemical cell. The ionic conductivities of C12mimBETI and C12imBETI were similar and increased linearly with an increase in temperature from 20 to 130°C. However, when used in the electrochemical system the protic water-equilibrated C12imBETI had a larger maximum current and power density compared to the aprotic water-equilibrated C12mimBETI. The effect of water content on the reaction rates and thermodynamics of these hydrophobic RTILs was also examined. The efficiency of the C12mimBETI increased upon removal of water while that of the C12imBETI decreased in efficiency when water was removed. The water structure in these RTILs was examined using attenuated total internal reflection Fourier transform IR spectroscopy and depended on the chemical structure of the cation. These studies give further insight into the possible mechanism of proton transport in these RTIL systems. PMID:20414470

  1. Ionic liquid ion source emitter arrays fabricated on bulk porous substrates for spacecraft propulsion

    E-print Network

    Courtney, Daniel George

    2011-01-01

    Ionic Liquid Ion Sources (ILIS) are a subset of electrospray capable of producing bipolar beams of pure ions from ionic liquids. Ionic liquids are room temperature molten salts, characterized by negligible vapor pressures, ...

  2. Volatile times for the very first ionic liquid: understanding the vapor pressures and enthalpies of vaporization of ethylammonium nitrate.

    PubMed

    Emel'yanenko, Vladimir N; Boeck, Gisela; Verevkin, Sergey P; Ludwig, Ralf

    2014-09-01

    A hundred years ago, Paul Walden studied ethyl ammonium nitrate (EAN), which became the first widely known ionic liquid. Although EAN has been investigated extensively, some important issues still have not been addressed; they are now tackled in this communication. By combining experimental thermogravimetric analysis with time of flight mass spectrometry (TGA-ToF-MS) and transpiration method with theoretical methods, we clarify the volatilisation of EAN from ambient to elevated temperatures. It was observed that up to 419?K, EAN evaporates as contact-ion pairs leading to very low vapour pressures of a few Pascal. Starting from 419?K, the decomposition to nitric acid and ethylamine becomes more thermodynamically favourable than proton transfer. This finding was supported by DFT calculations, which provide the free energies of all possible gas-phase species, and show that neutral molecules dominate over ion pairs above 500?K, an observation that is in nearly prefect agreement with the experimental boiling point of 513?K. This result is crucial for the ongoing practical applications of protic ionic liquids such as electrolytes for batteries and fuel cells because, in contrast to high-boiling conventional solvents, EAN exhibits no significant vapour pressure below 419?K and this property fulfils the requirements for the thermal behaviour of safe electrolytes. Overall, EAN shows the same barely measurable vapour pressures as typical aprotic ionic liquids at temperatures only 70?K lower. PMID:25077820

  3. Brownian dynamics determine universality of charge transport in ionic liquids

    SciTech Connect

    Sangoro, Joshua R [ORNL; Iacob, Ciprian [University of Leipzig; Mierzwa, Michal [University of Silesia, Uniwersytecka, Katowice, Poland; Paluch, Marian [University of Silesia, Uniwersytecka, Katowice, Poland; Kremer, Friedrich [University of Leipzig

    2012-01-01

    Broadband dielectric spectroscopy is employed to investigate charge transport in a variety of glass-forming ionic liquids over wide frequency, temperature and pressure ranges. Using a combination of Einstein, Einstein-Smoluchowski, and Langevin relations, the observed universal scaling of charge transport in ionic liquids is traced back to the dominant role of Brownian dynamics.

  4. Ionic liquids with ammonium cations as lubricants or additives

    Microsoft Academic Search

    Jun Qu; J. J. Truhan; Sheng Dai; Huimin Luo; P. J. Blau

    2006-01-01

    A new class of more effective lubricants could lead to huge energy savings. Limited recent literature has suggested potential for using room-temperature ionic liquids as lubricants, however, only a few out of millions (or more) of species possible have been evaluated. In this study, a series of new protic alkylammonium ionic liquids were synthesized by neutralization and metathesis reactions, and

  5. Structure and magnetic behavior of transition metal based ionic liquids

    SciTech Connect

    Del Sesto, Rico E [Los Alamos National Laboratory (LANL); Mccleskey, T [Los Alamos National Laboratory (LANL); Burrell, Anthony K [ORNL; Baker, Gary A [ORNL; Thompson, Joe D. [Los Alamos National Laboratory (LANL); Scott, Brian L. [Los Alamos National Laboratory (LANL); Wilkes, John S [United States Air Force Academy (USAFA), Colorado; Williams, Peg [United States Air Force Academy (USAFA), Colorado

    2008-01-01

    A series of ionic liquids containing different paramagnetic anions have been prepared and all show paramagnetic behavior with potential applications for magnetic and electrochromic switching as well as novel magnetic transport; also, the tetraalkylphosphonium-based ionic liquids reveal anomalous magnetic behavior.

  6. The Hildebrand Solubility Parameters of Ionic Liquids—Part 2

    PubMed Central

    Marciniak, Andrzej

    2011-01-01

    The Hildebrand solubility parameters have been calculated for eight ionic liquids. Retention data from the inverse gas chromatography measurements of the activity coefficients at infinite dilution were used for the calculation. From the solubility parameters, the enthalpies of vaporization of ionic liquids were estimated. Results are compared with solubility parameters estimated by different methods. PMID:21747694

  7. High ionicity ionic liquids (HIILs): comparing the effect of ethylsulfonate and ethylsulfate anions.

    PubMed

    Oliveira, Filipe S; Pereiro, Ana B; Araújo, João M M; Bernardes, Carlos E S; Canongia Lopes, José N; Todorovic, Smilja; Feio, Gabriel; Almeida, Pedro L; Rebelo, Luís P N; Marrucho, Isabel M

    2013-11-01

    The subject of ionicity has been extensively discussed in the last decade, due to the importance of understanding the thermodynamic and thermophysical behaviour of ionic liquids. In our previous work, we established that ionic liquids' ionicity could be improved by the dissolution of simple inorganic salts in their milieu. In this work, a comparison between the thermophysical properties of two binary systems of ionic liquid + inorganic salt is presented. The effect of the ammonium thiocyanate salt on the ionicity of two similar ionic liquids, 1-ethyl-3-methylimidazolium ethylsulfonate and ethylsulfate, is investigated in terms of the related thermophysical properties, such as density, viscosity and ionic conductivity in the temperature range 298.15-323.15 K. In addition, spectroscopic (NMR and Raman) and molecular dynamic studies were conducted in order to better understand the interactions that occur at a molecular level. The obtained results reveal that although the two anions of the ionic liquid exhibit similar chemical structures, the presence of one additional oxygen in the ethylsulfate anion has a major impact on the thermophysical properties of the studied systems. PMID:24061089

  8. Designer molecular probes for phosphonium ionic liquids.

    PubMed

    Byrne, Robert; Coleman, Simon; Gallagher, Simon; Diamond, Dermot

    2010-02-28

    Investigations into the extent of structuring present in phosphonium based ionic liquids (ILs) have been carried out using photochromic molecular probes. Three spiropyran derivatives containing hydroxyl (BSP-1), carboxylic acid (BSP-2) and aliphatic chain (C(14)H(29)) (BSP-3) functional groups have been analysed in a range of phosphonium based ionic liquids and their subsequent physico-chemical interactions were reported. It is believed that the functional groups locate the probe molecules into specific regions based upon the interaction of the functional groups with particular and defined regions of the ionic liquid. This structuring results in thermodynamic, kinetic and solvatochromic parameters that are not predictable from classical solvent models. BSP-1 and BSP-2 exhibit generally negative entropies of activation ranging from -50 J K(-1) mol(-1) to -90 J K(-1) mol(-1) implying relatively low solvent-solute interactions and possible anion interactions with IL polar functional groups. Higher than expected activation energies of 60 kJ mol(-1) to 100 kJ mol(-1) obtained for polar probes maybe be due to IL functional groups competing with the charged sites of the merocyanine (MC) isomer thus reducing MC stabilisation effects. Differences in thermal relaxation rate constants (2.5 x 10(-3) s(-1) in BSP-1 and 3 x 10(-4) s(-1) in BSP-2 in [P(6,6,6,14)][dbsa]) imply that while the polar probe systems are primarily located in polar/charged regions, each probe experiences slightly differing polar domains. BSP-3 entropies of activation are positive and between 30 J K(-1) mol(-1) to 66 J K(-1) mol(-1). The association of the non-polar functional group is believed to locate the spiropyran moiety in the interfacial polar and non-polar regions. The thermal relaxation of the MC form causes solvent reorientation to accommodate the molecule as it reverts to its closed form. Slow thermal relaxation rate constants were obserevd in contrast to high activation energies (5 x 10(-4) s(-1) and 111.91 kJ mol(-1) respectively, for BSP-3 in [P(6,6,6,14)][dbsa]). This may be due to steric effects arising from proposed nano-cavity formation by the alkyl chains in phosphonium based ILs. PMID:20145857

  9. Quantitative structure-activity relationship (QSAR) prediction of (eco)toxicity of short aliphatic protic ionic liquids.

    PubMed

    Peric, Brezana; Sierra, Jordi; Martí, Esther; Cruañas, Robert; Garau, Maria Antonia

    2015-05-01

    Ionic liquids (ILs) are considered as a group of very promising compounds due to their excellent properties (practical non-volatility, high thermal stability and very good and diverse solving capacity). The ILs have a good prospect of replacing traditional organic solvents in vast variety of applications. However, the complete information on their environmental impact is still not available. There is also an enormous number of possible combinations of anions and cations which can form ILs, the fact that requires a method allowing the prediction of toxicity of existing and potential ILs. In this study, a group contribution QSAR model has been used in order to predict the (eco)toxicity of protic and aprotic ILs for five tests (Microtox®, Pseudokirchneriella subcapitata and Lemna minor growth inhibition test, and Acetylcholinestherase inhibition and Cell viability assay with IPC-81 cells). The predicted and experimental toxicity are well correlated. A prediction of EC50 for these (eco)toxicity tests has also been made for eight representatives of the new family of short aliphatic protic ILs, whose toxicity has not been determined experimentally to date. The QSAR model applied in this study can allow the selection of potentially less toxic ILs amongst the existing ones (e.g. in the case of aprotic ILs), but it can also be very helpful in directing the synthesis efforts toward developing new "greener" ILs respectful with the environment (e.g. short aliphatic protic ILs). PMID:25728357

  10. Polarization versus temperature in pyridinium ionic liquids.

    PubMed

    Chaban, Vitaly V; Prezhdo, Oleg V

    2014-12-01

    Electronic polarization and charge transfer effects play a crucial role in thermodynamic, structural, and transport properties of room-temperature ionic liquids (RTILs). These nonadditive interactions constitute a useful tool for tuning physical chemical behavior of RTILs. Polarization and charge transfer generally decay as temperature increases, although their presence should be expected over an entire condensed state temperature range. For the first time, we use three popular pyridinium-based RTILs to investigate temperature dependence of electronic polarization in RTILs, based on a nonperiodic electronic density description for a cation-anion pair. Atom-centered density matrix propagation molecular dynamics, supplemented by a weak coupling to an external bath, is used to simulate the temperature impact on system properties. We show that, quite surprisingly, nonadditivity in the cation-anion interactions changes negligibly between 300 and 900 K, while the average dipole moment increases due to thermal fluctuations of geometries. Our results contribute to the fundamental understanding of electronic effects in the condensed phase of ionic systems and foster progress in physical chemistry and engineering. PMID:25387327

  11. Ionic liquids as advanced lubricant fluids.

    PubMed

    Bermúdez, María-Dolores; Jiménez, Ana-Eva; Sanes, José; Carrión, Francisco-José

    2009-01-01

    Ionic liquids (ILs) are finding technological applications as chemical reaction media and engineering fluids. Some emerging fields are those of lubrication, surface engineering and nanotechnology. ILs are thermally stable, non-flammable highly polar fluids with negligible volatility, these characteristics make them ideal candidates for new lubricants under severe conditions, were conventional oils and greases or solid lubricants fail. Such conditions include ultra-high vacuum and extreme temperatures. Other very promising areas which depend on the interaction between IL molecules and material surfaces are the use of ILs in the lubrication of microelectromechanic and nanoelectromechanic systems (MEMS and NEMS), the friction and wear reduction of reactive light alloys and the modification of nanophases. PMID:19701132

  12. Durable electrooptic devices comprising ionic liquids

    DOEpatents

    Warner, Benjamin P. (Los Alamos, NM); McCleskey, T. Mark (Los Alamos, NM); Burrell, Anthony K. (Los Alamos, NM)

    2006-10-10

    Electrolyte solutions for electrochromic devices such as rear view mirrors and displays with low leakage currents are prepared using inexpensive, low conductivity conductors. Preferred electrolytes include bifunctional redox dyes and molten salt solvents with enhanced stability toward ultraviolet radiation. The solvents include lithium or quaternary ammonium cations, and perfluorinated sulfonylimide anions selected from trifluoromethylsulfonate (CF.sub.3SO.sub.3.sup.-), bis(trifluoromethylsulfonyl)imide ((CF.sub.3SO.sub.2).sub.2N.sup.-), bis(perfluoroethylsulfonyl)imide ((CF.sub.3CF.sub.2SO.sub.2).sub.2N.sup.-) and tris(trifluoromethylsulfonyl)methide ((CF.sub.3SO.sub.2).sub.3C.sup.-). Electroluminescent, electrochromic and photoelectrochromic devices with nanostructured electrodes include ionic liquids with bifunctional redox dyes.

  13. Ionic liquids as plasticizers for polyelectrolyte complexes.

    PubMed

    Zhang, Bodong; Hoagland, David A; Su, Zhaohui

    2015-02-26

    Uptake of salts by insoluble polyelectrolyte complexes (PECs) leads to plasticization, and here it is shown that ionic liquids (ILs) are more effective plasticizers than simple organic salts such as NaCl. The PEC uptake of IL cation was monitored by solution (1)H NMR, and the mechanical impacts of plasticization were tracked by dynamic mechanical analysis (DMA). PECs prepared with polystyrene sulfonate (PSS) and poly(diallyldimethylammonium chloride) (PDDA) under charge stoichiometric conditions were immersed in aqueous solutions of 1-butyl-3-methylimidazolium chloride [BMIM][Cl] to cause IL uptake, which could be controlled by the solution's IL concentration: higher concentration leads to higher uptake which leads to greater plasticization. The effectiveness of plasticization was assessed through the position and height of a DMA tan(?) peak ascribed to a glassy-to-rubbery PEC transition. Consistent with greater PEC uptake, isothermal titration calorimetry demonstrated that solution binding by PSS of [BMIM](+) was much stronger than binding of Na(+). PMID:25686291

  14. Graphene terahertz modulators by ionic liquid gating

    E-print Network

    Wu, Yang; Qiu, Xuepeng; Liu, Jingbo; Deorani, Praveen; Banerjee, Karan; Son, Jaesung; Chen, Yuanfu; Chia, Elbert E M; Yang, Hyunsoo

    2015-01-01

    Graphene based THz modulators are promising due to the conical band structure and high carrier mobility of graphene. Here, we tune the Fermi level of graphene via electrical gating with the help of ionic liquid to control the THz transmittance. It is found that, in the THz range, both the absorbance and reflectance of the device increase proportionately to the available density of states due to intraband transitions. Compact, stable, and repeatable THz transmittance modulation up to 93% (or 99%) for a single (or stacked) device has been demonstrated in a broad frequency range from 0.1 to 2.5 THz, with an applied voltage of only 3 V at room temperature.

  15. 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. PMID:19586072

  16. Metsulfuron-methyl-based herbicidal ionic liquids.

    PubMed

    Pernak, Juliusz; Niemczak, Micha?; Shamshina, Julia L; Gurau, Gabriela; G?owacki, Grzegorz; Praczyk, Tadeusz; Marcinkowska, Katarzyna; Rogers, Robin D

    2015-04-01

    Ten sulfonylurea-based herbicidal ionic liquids (HILs) were prepared by combining the metsulfuron-methyl anion with various cation types including quaternary ammonium ([bis(2-hydroxyethyl)methyloleylammonium](+), [2-hydroxyethyltrimethylammonium](+)), pyridinium ([1-dodecylpyridinium](+)), piperidinium ([1-methyl-1-propylpiperidinium](+)), imidazolium ([1-allyl-3-methylimidazolium](+), [1-butyl-3-methylimidazolium](+)), pyrrolidinium ([1-butyl-1-methylpyrrolidinium](+)), morpholinium ([4-decyl-4-methylmorpholinium](+)), and phosphonium ([trihexyltetradecylphosphonium](+) and [tetrabutylphosphonium](+)). Their herbicidal efficacy was studied in both greenhouse tests and field trials. Preliminary results for the greenhouse tests showed at least twice the activity for all HILs when compared to the activity of commercial Galmet 20 SG, with HILs with phosphonium cations being the most effective. The results of two-year field studies showed significantly less enhancement of activity than observed in the greenhouse; nonetheless, it was found that the herbicidal efficacy was higher than that of the commercial analog, and efficacy varied depending on the plant species. PMID:25734891

  17. Halogenation of Imidazolium Ionic Liquids. Thermodynamics Perspective

    E-print Network

    Chaban, Vitaly V

    2015-01-01

    Imidazolium cations are promising for anion exchange membranes, and electrochemical applications and gas capture. They can be chemically modified in many ways including halogenation. Halogenation possibilities of the imidazole ring constitute a particular interest. This work investigates fluorination and chlorination reactions of all symmetrically non-equivalent sites of the imidazolium cation. Halogenation of all carbon atoms is thermodynamically permitted. Out of these, the most favorable site is the first methylene group of the alkyl chain. In turn, the least favorable site is carbon of the imidazole ring. Temperature dependence of enthalpy, entropy, and Gibbs free energy at 1 bar is discussed. The reported results provide an important guidance in functionalization of ionic liquids in search of task-specific compounds.

  18. Femtosecond solvation dynamics in a neat ionic liquid and ionic liquid microemulsion: excitation wavelength dependence.

    PubMed

    Adhikari, Aniruddha; Sahu, Kalyanasis; Dey, Shantanu; Ghosh, Subhadip; Mandal, Ujjwal; Bhattacharyya, Kankan

    2007-11-01

    Solvation dynamics in a neat ionic liquid, 1-pentyl-3-methyl-imidazolium tetra-flouroborate ([pmim][BF4]) and its microemulsion in Triton X-100 (TX-100)/benzene is studied using femtosecond up-conversion. In both the neat ionic liquid and the microemulsion, the solvation dynamics is found to depend on excitation wavelength (lambda(ex)). The lambda(ex) dependence is attributed to structural heterogeneity in neat ionic liquid (IL) and in IL microemulsion. In neat IL, the heterogeneity arises from clustering of the pentyl groups which are surrounded by a network of cation and anions. Such a nanostructural organization is predicted in many recent simulations and observed recently in an X-ray diffraction study. In an IL microemulsion, the surfactant (TX-100) molecules aggregate in form of a nonpolar peripheral shell around the polar pool of IL. The micro-environment in such an assembly varies drastically over a short distance. The dynamic solvent shift (and average solvation time) in neat IL as well as in IL microemulsions decreases markedly as lambda(ex) increases from 375 to 435 nm. In a [pmim][BF4]/water/TX-100/benzene quaternary microemulsion, the solvation dynamics is slower than that in a microemulsion without water. This is ascribed to the smaller size of the water containing microemulsion. The anisotropy decay in an IL microemulsion is found to be faster than that in neat IL. PMID:17944511

  19. Biphasic liquid mixtures of ionic liquids and polyethylene glycols.

    PubMed

    Rodríguez, Héctor; Francisco, María; Rahman, Mustafizur; Sun, Ning; Rogers, Robin D

    2009-12-14

    We have found that 1-alkyl-3-methylimidazolium chloride ionic liquids (ILs) can form immiscible liquid mixtures with some polyethylene glycols (PEGs). Binary mixtures of 1-ethyl-3-methylimidazolium chloride with PEG of molecular weight 1500, 2000, or 3400 g mol(-1), or of 1-butyl-3-methylimidazolium chloride with PEG of molecular weight 2000 or 3400 g mol(-1), have been found to give rise to entirely liquid, stable biphasic systems over a significant temperature range (from 333.15 K to 413.15 K), while mixtures of 1-ethyl-3-methylimidazolium chloride with PEG-1000 and 1-butyl-3-methylimidazolium chloride with PEG-1000 and PEG-1500 are miscible. The mutual immiscibility of the IL and the PEG increases as the temperature increases. The evolution of the composition of the phases in equilibrium with the molecular weight of the PEG, or with the variation of the length of the alkyl substituent chain of the imidazolium cation of the IL, has been explored. The trends observed are explained through the complexity of interactions present within the binary system. A thermodynamic analysis of the liquid-liquid equilibrium data indicates negative values for the change of enthalpy and entropy of mixing. The potential application of these biphasic, entirely liquid systems, with low volatility and good solvation properties, for the dissolution and separation of cellulose and lignin at elevated temperature has been preliminarily explored, although only modest results have been achieved to date. PMID:19924326

  20. Liquid-liquid extraction of neodymium(III) by dialkylphosphate ionic liquids from acidic medium: the importance of the ionic liquid cation.

    PubMed

    Rout, Alok; Kotlarska, Justyna; Dehaen, Wim; Binnemans, Koen

    2013-10-21

    The ionic liquids 1-hexyl-3-methylimidazolium bis(2-ethylhexyl)phosphate, [C6mim][DEHP], 1-hexyl-1-methylpyrrolidinium bis(2-ethylhexyl)phosphate, [C6mpyr][DEHP], and tetrabutylammonium bis(2-ethylhexyl)phosphate, [N4444][DEHP], were prepared and characterized using (1)H and (13)C NMR spectroscopy. The extraction behavior of neodymium(iii) from nitrate medium by these ionic liquids, diluted with the room temperature ionic liquids 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [C6mim][NTf2], 1-hexyl-3-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, [C6mpyr][NTf2], and tributylmethylammonium bis(trifluoromethylsulfonyl)imide, [N1444][NTf2], was studied. The distribution ratio of neodymium(iii) was measured as a function of various parameters, such as pH, concentration of the ionic liquid extractant, nature of diluents, concentration of ionic liquid cations and nitrate anions in the aqueous phase. The extraction behavior was compared with that obtained for a solution of the molecular extractant bis(2-ethylhexyl)phosphoric acid (DEHPA) in an ionic liquid diluent. The extraction of neodymium(iii) in the ionic liquids [C6mim][DEHP] and [C6mpyr][DEHP] showed markedly different extraction properties in comparison with that of the quaternary ammonium analogue [N4444][DEHP], especially concerning the pH dependence of the extraction process. These results show that the extraction process can be tuned by the selection of the ionic liquid cation. The extraction experiments also included the trivalent rare-earth ions lanthanum(iii), cerium(iii), praseodymium(iii), ytterbium(iii) and yttrium(iii). Studies of the stripping behavior and the reusability of the ionic liquids were carried out, which indicate that the ionic liquids can be reused with no loss in activity. PMID:23949284

  1. Inorganic or organic azide-containing hypergolic ionic liquids.

    PubMed

    Joo, Young-Hyuk; Gao, Haixiang; Zhang, Yanqiang; Shreeve, Jean'ne M

    2010-04-01

    Recently extensive research has focused on replacing toxic hydrazine, monomethylhydrazine, and unsymmetrical dimethylhydrazine as liquid propellant fuels. 2-Azido-N,N-dimethylethylamine (1) is a good candidate to replace hydrazine derivatives in certain hypergolic fuel applications. Energetic ionic liquids that contain the 2-azido-N,N,N-trimethylethylammonium cation with nitrocyanamide, dicyanamide, dinitramide, or azide anion have been successfully synthesized in good yields by metathesis reactions. Ionic liquids have received considerable attention as energetic materials. The replacement of hydrazine with tertiary ammonium salts is especially attractive since many ionic liquids are models for green chemistry. In this work, new azide-functionalized ionic liquids are demonstrated to exhibit hypergolic activity with such oxidizers as 100% nitric acid or nitrogen tetraoxide (NTO). PMID:20175509

  2. Ionogels, ionic liquid based hybrid materials.

    PubMed

    Le Bideau, Jean; Viau, Lydie; Vioux, André

    2011-02-01

    The current interest in ionic liquids (ILs) is motivated by some unique properties, such as negligible vapour pressure, thermal stability and non-flammability, combined with high ionic conductivity and wide electrochemical stability window. However, for material applications, there is a challenging need for immobilizing ILs in solid devices, while keeping their specific properties. In this critical review, ionogels are presented as a new class of hybrid materials, in which the properties of the IL are hybridized with those of another component, which may be organic (low molecular weight gelator, (bio)polymer), inorganic (e.g. carbon nanotubes, silica etc.) or hybrid organic-inorganic (e.g. polymer and inorganic fillers). Actually, ILs act as structuring media during the formation of inorganic ionogels, their intrinsic organization and physicochemical properties influencing the building of the solid host network. Conversely, some effects of confinement can modify some properties of the guest IL, even though liquid-like dynamics and ion mobility are preserved. Ionogels, which keep the main properties of ILs except outflow, while allowing easy shaping, considerably enlarge the array of applications of ILs. Thus, they form a promising family of solid electrolyte membranes, which gives access to all-solid devices, a topical industrial challenge in domains such as lithium batteries, fuel cells and dye-sensitized solar cells. Replacing conventional media, organic solvents in lithium batteries or water in proton-exchange-membrane fuel cells (PEMFC), by low-vapour-pressure and non flammable ILs presents major advantages such as improved safety and a higher operating temperature range. Implementation of ILs in separation techniques, where they benefit from huge advantages as well, relies again on the development of supported IL membranes such as ionogels. Moreover, functionalization of ionogels can be achieved both by incorporation of organic functions in the solid matrix, and by encapsulation of molecular species (from metal complexes to enzymes) in the immobilized IL phase, which opens new routes for designing advanced materials, especially (bio)catalytic membranes, sensors and drug release systems (194 references). PMID:21180731

  3. Electrochemical transistors with ionic liquids for enzymatic sensing

    E-print Network

    Lee, Hyowon

    liquids (ILs) are low melting salts, thus forming liquids that are comprised entirely of cations and anions. According to the current convention, a salt melting below the normal boiling point of water is known as an "ionic liquid" or by one of many synonyms including low / ambient / room temperature molten

  4. Long-range electrostatic screening in ionic liquids.

    PubMed

    Gebbie, Matthew A; Dobbs, Howard A; Valtiner, Markus; Israelachvili, Jacob N

    2015-06-16

    Electrolyte solutions with high concentrations of ions are prevalent in biological systems and energy storage technologies. Nevertheless, the high interaction free energy and long-range nature of electrostatic interactions makes the development of a general conceptual picture of concentrated electrolytes a significant challenge. In this work, we study ionic liquids, single-component liquids composed solely of ions, in an attempt to provide a novel perspective on electrostatic screening in very high concentration (nonideal) electrolytes. We use temperature-dependent surface force measurements to demonstrate that the long-range, exponentially decaying diffuse double-layer forces observed across ionic liquids exhibit a pronounced temperature dependence: Increasing the temperature decreases the measured exponential (Debye) decay length, implying an increase in the thermally driven effective free-ion concentration in the bulk ionic liquids. We use our quantitative results to propose a general model of long-range electrostatic screening in ionic liquids, where thermally activated charge fluctuations, either free ions or correlated domains (quasiparticles), take on the role of ions in traditional dilute electrolyte solutions. This picture represents a crucial step toward resolving several inconsistencies surrounding electrostatic screening and charge transport in ionic liquids that have impeded progress within the interdisciplinary ionic liquids community. More broadly, our work provides a previously unidentified way of envisioning highly concentrated electrolytes, with implications for diverse areas of inquiry, ranging from designing electrochemical devices to rationalizing electrostatic interactions in biological systems. PMID:26040001

  5. The Radiation Chemistry of Ionic Liquids: A Review

    SciTech Connect

    Mincher, Bruce J. [Idaho National Lab. (INL), Idaho Falls, ID (United States). Aqueous Separations and Radiochemistry Dept.; Wishart, James F. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2014-07-03

    Ionic liquids have received increasing attention as media for radiochemical separations. Recent literature includes examinations of the efficiencies and mechanisms of the solvent extraction of lanthanides, actinides and fission products into ionic liquid solutions. For radiochemical applications, including as replacement solvents for nuclear fuel reprocessing, a thorough understanding of the radiation chemistry of ionic liquids will be required. Such an understanding can be achieved based upon a combination of steady-state radiolysis experiments coupled with post-irradiation product identification and pulse-radiolysis experiments to acquire kinetic information. These techniques allow for the elucidation of radiolytic mechanisms. This contribution reviews the current ionic liquid radiation chemistry literature as it affects separations, with these considerations in mind.

  6. The radiation chemistry of ionic liquids: a review

    DOE PAGESBeta

    Mincher, Bruce J.; Wishart, James F.

    2014-07-03

    Ionic liquids have received increasing attention as media for radiochemical separations. Recent literature includes examinations of the efficiencies and mechanisms of the solvent extraction of lanthanides, actinides and fission products into ionic liquid solutions. For radiochemical applications, including as replacement solvents for nuclear fuel reprocessing, a thorough understanding of the radiation chemistry of ionic liquids will be required. Such an understanding can be achieved based upon a combination of steady-state radiolysis experiments coupled with post-irradiation product identification and pulse-radiolysis experiments to acquire kinetic information. These techniques allow for the elucidation of radiolytic mechanisms. This contribution reviews the current ionic liquid radiation chemistry literature as it affects separations, with these considerations in mind.

  7. Tribological Properties of Ionic Liquids Lubricants Containing Nanoparticles 

    E-print Network

    Lu, Wei

    2014-05-14

    Recently, there has been an increase in research in the application of ionic liquids containing nanoparticles as lubricants due to their properties such as thermally stability, non-volatility and non-flammability. The ...

  8. Tribological Properties of Ionic Liquids Lubricants Containing Nanoparticles

    E-print Network

    Lu, Wei

    2014-05-14

    Recently, there has been an increase in research in the application of ionic liquids containing nanoparticles as lubricants due to their properties such as thermally stability, non-volatility and non-flammability. The purpose of this thesis...

  9. Membrane contactor assisted extraction/reaction process employing ionic liquids

    DOEpatents

    Lin, Yupo J. (Naperville, IL); Snyder, Seth W. (Lincolnwood, IL)

    2012-02-07

    The present invention relates to a functionalized membrane contactor extraction/reaction system and method for extracting target species from multi-phase solutions utilizing ionic liquids. One preferred embodiment of the invented method and system relates to an extraction/reaction system wherein the ionic liquid extraction solutions act as both extraction solutions and reaction mediums, and allow simultaneous separation/reactions not possible with prior art technology.

  10. Tribo-Chemistry of Phosphonium-Derived Ionic Liquids

    Microsoft Academic Search

    Ichiro Minami; Taketo Inada; Ryusuke Sasaki; Hidetaka Nanao

    2010-01-01

    The tribological properties of room temperature ionic liquids containing tetraalkylphosphonium cations were evaluated on the\\u000a basis of the chemical structure of their salts. The tribochemistry of these ionic liquids was discussed on the basis of the\\u000a results of tribo-tests and surface analyses. The tribological properties of the tetraalkylphosphonium salts examined in this\\u000a work were observed to be better than those

  11. Tribological Performance of Room-Temperature Ionic Liquids as Lubricant

    Microsoft Academic Search

    Weimin Liu; Chengfeng Ye; Qingye Gong; Haizhong Wang; Peng Wang

    2002-01-01

    The tribological performance of room-temperature ionic liquid of alkylimidazolium tetrafluoroborate was evaluated using an Optimol SRV oscillating friction and wear tester in air and a CZM vacuum friction tester in vacuum (1×10-3 Pa) using a steel\\/steel (SAE52100) contact. From the results, the ionic liquid exhibits excellent friction-reduction, antiwear proprieties, both in air and vacuum, which are superior to phosphazene (X-1P)

  12. The Pressure–Viscosity Coefficient of Several Ionic Liquids

    Microsoft Academic Search

    A. S. Pensado; M. J. P. Comuñas; J. Fernández

    2008-01-01

    The choice of cation and anion in an ionic liquid (IL) as well as the design of ion side chains determine the fundamental\\u000a properties of ILs, which permits creating tailor-made lubricants and lubricant additives. So, the study of the influence\\u000a of molecular structure on thermophysical properties of ionic liquids is essential for their use in lubrication. Recent results\\u000a from the

  13. Nanoscale organization in piperidinium-based room temperature ionic liquids

    NASA Astrophysics Data System (ADS)

    Triolo, Alessandro; Russina, Olga; Fazio, Barbara; Appetecchi, Giovanni Battista; Carewska, Maria; Passerini, Stefano

    2009-04-01

    Here we report on the complex nature of the phase diagram of N-alkyl-N-methylpiperidinium bis(trifluoromethanesulfonyl)imide ionic liquids using several complementary techniques and on their structural order in the molten state using small-wide angle x-ray scattering. The latter study indicates that the piperidinium aliphatic alkyl chains tend to aggregate, forming alkyl domains embedded into polar regions, similar to what we recently highlighted in the case of other ionic liquids.

  14. Electrokinetics of Correlated Electrolytes and Ionic Liquids

    NASA Astrophysics Data System (ADS)

    Storey, Brian; Bazant, Martin

    2011-11-01

    Perhaps the most basic assumption of classical electrokinetic theory is the mean-field approximation, where the each ion feels only the electric field produced by the mean charge density (via Poisson's equation) rather than the fluctuating Coulomb forces with individual neighbors. Here, we present a simple continuum model for electrostatic correlations between finite-sized ions, which leads to a 4th order modified Poisson equation, convenient for the analysis of electrokinetic phenomena. When the mean-field approximation breaks down, e.g. due to large ion concentrations, large ion valences, and/or nanoscale confinement, the zeta potential loses its significance, and the model predicts that electro-osmotic flows are typically reduced - or even reversed - by correlation effects, compared to the prediction of the Helmholtz-Smoluchowski formula. This may help to explain the over-prediction of induced-charge electro-osmotic flows by classical models. An interesting limit of the model describes electro-osmosis in solvent-free ionic liquids and molten salts, which may be important in energy storage and electroactuation applications.

  15. Resonance shear measurement of nanoconfined ionic liquids.

    PubMed

    Ueno, Kazuhide; Kasuya, Motohiro; Watanabe, Masayoshi; Mizukami, Masashi; Kurihara, Kazue

    2010-04-28

    Two types of imidazolium-based ionic liquid (IL), 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide ([C(4)mim][NTF(2)]) and 1-butyl-3-methylimidazolium tetrafluoroborate ([C(4)mim][BF(4)]), confined between silica surfaces were investigated by surface force apparatus (SFA)-based resonance shear measurements together with surface force measurements. The surface force profiles in the ILs showed oscillatory solvation forces below the characteristic surface separations: 10.0 nm for [C(4)mim][NTf(2)] and 6.9 nm for [C(4)mim][BF(4)]. The more pronounced solvation force found in [C(4)mim][NTf(2)] suggests that the crystal-forming ability of the IL contributes to the stronger layering of the ILs adjacent to the surface. The resonance shear measurement and the physical model analysis revealed that the viscosities of the confined ILs were 1-3 orders of magnitude higher than that of the bulk IL. This paper also focused on the correlation between the resonance shear behaviour and the lubrication property of the ILs, and the suspension rheology in the ILs. An understanding of the solid-IL interface and of ILs confined in nanospace will facilitate the further development of novel applications employing ILs. PMID:20379497

  16. Biocompatible Ionic Liquid-Derived Conducting Polymers

    NASA Astrophysics Data System (ADS)

    Firestone, Millicent; Burns, Christopher; Lee, Sungwon

    2009-03-01

    A significant and frequently encountered challenge when making an electrical connection to a protein is that its electron-transfer sites are buried within the polypeptide matrix and thus, are not readily accessible to bulk metal electrodes. A further complicating factor is that inorganic (i.e., metallic) electrodes are often incompatible with biological samples. These obstacles might be overcome by the use of conducting oligomers and / or polymers, which are flexible, offering a means to access remote redox centers. These oligomers can be readily modified to include chemical moieties that can connect covalently to sites near redox centers. In addition, conducting polymers can be made to be environmentally responsive (dynamic), processable (conformal coating, soluble) and mechanically durable, thus enabling them to function as an electrical conduit (wire or electrode) to biomolecules. In this work, we describe the design, synthesis and electrochemical properties of thiophene-based ionic liquid monomers and their bulk polymerization by chemical oxidation to yield cationic, aqueous-soluble polymers. Preliminary studies evaluating the electropolymerization of these monomers into nanostructured thin films will also be presented.

  17. SemiEmpirical Molecular Modeling of Ionic Liquid Tribology: Ionic Liquid–Aluminum Oxide Surface Interactions

    Microsoft Academic Search

    W. Robert Carper; Phillip G. Wahlbeck; Naveed S. Nooruddin

    The interactions between the selected ionic liquids (ILs) and aluminum oxide surfaces are modeled in this report using theoretical\\u000a methods. A wide range of ILs and their interactions with an aluminum oxide surface are modeled using the PM5 semi-empirical\\u000a method. The ILs modeled in this study contain imidazolium (C3, 4, 6, 8 or 10mim) or ammonium cations including (C6H13)3NH+, (C8H17)3NH+,

  18. Ionic Liquids with Ammonium Cations as Lubricants or Additives

    SciTech Connect

    Qu, Jun [ORNL; Blau, Peter Julian [ORNL; Dai, Sheng [ORNL; Luo, Huimin [ORNL; Truhan, Jr., John J [ORNL

    2006-01-01

    Friction and wear are estimated to cost 6% of the US gross national product, or around $700 billion annually. A new class of more effective lubricants could lead to huge energy savings. Limited recent literature has suggested potential for using room-temperature ionic liquids as lubricants, however only a few out of millions (or more) of species have been evaluated. Recent ORNL work discovered a new category of ionic liquids with ammonium cations that have demonstrated promising lubricating properties as net lubricants or lubricant additives, particularly in lubricating difficult-to-lubricate metals like aluminum. More than 30% friction reduction has been observed on ammonium-based ionic liquids compared to conventional hydrocarbon oils. The inherent polarity of ionic liquids is believed to provide strong adhesion to contact surfaces and form a boundary lubricating film leading to friction and wear reductions. Other advantages of ionic liquids include (1) negligible volatility, (2) high thermal stability, (3) non-flammability, and (4) better intrinsic properties that eliminate the necessity of many expensive lubricant additives. With very flexible molecular structures, this new class of lubricants, particularly ammonium-based ionic liquids, can be tailored to fit a big variety of applications including but not limited to bearings, combustion engines, MEMS, and metal forming.

  19. Ionic liquids and electrochemistry: from proteins to electrochromic devices.

    SciTech Connect

    Keizer, T. S. (Timothy S.); McCleskey, T. M. (Thomas Mark); Baker, G. A. (Gary A.); Burrell, A. K. (Anthony K.); Baker, S. N. (Sheila N.); Warner, B. P. (Benjamin P.); Hall, S. B. (Simon B.)

    2004-01-01

    We will report on a wide range of activities within the chemistry division at Los Alamos National Laboratory. Results on basic and applied research involving electrochemistry will be discussed. Topics will include electrochemistry of proteins, sensors based on electrochemical signals, temperature sensors, electrochromic devices in ionic liquids and the characterization of organic cation radicals. We have recently developed several applications in ionic liquids that include electrochromic devices, temperature sensors and chemical sensors. The electrochromic windows are being marketed as selftinting automotive mirrors. The ionic liquid based temperature sensor is stable and accurate over a wide range and has the potential to provide high-resolution temperature imaging. Chemical sensors have been developed that use electrochemistry to detect low levels of potential chemical agents in air. We have also studied the basic chemistry of charge transfer complexes and proteins in ionic liquids. Charge transfer complexes display unique behavior in ionic liquid compare to traditional solvents. Proteins can be solubilized at high levels that make it possible to probe electrochemistry in the proper ionic liquid.

  20. Carbon Dioxide Separation with Supported Ionic Liquid Membranes

    SciTech Connect

    Luebke, D.R.; Ilconich, J.B.; Myers, C.R.; Pennline, H.W.

    2007-04-01

    Supported liquid membranes are a class of materials that allow the researcher to utilize the wealth of knowledge available on liquid properties as a direct guide in the development of a capture technology. These membranes also have the advantage of liquid phase diffusivities higher than those observed in polymeric membranes which grant proportionally greater permeabilities. The primary shortcoming of the supported liquid membranes demonstrated in past research has been the lack of stability caused by volatilization of the transport liquid. Ionic liquids, which possess high carbon dioxide solubility relative to light gases such as hydrogen, are an excellent candidate for this type of membrane since they have negligible vapor pressure and are not susceptible to evaporation. A study has been conducted evaluating the use of several ionic liquids, including 1-hexyl-3-methyl-imidazolium bis(trifuoromethylsulfonyl)imide, 1-butyl-3-methyl-imidazolium nitrate, and 1-ethyl-3-methyl-imidazolium sulfate in supported ionic liquid membranes for the capture of carbon dioxide from streams containing hydrogen. In a joint project, researchers at the University of Notre Dame lent expertise in ionic liquid synthesis and characterization, and researchers at the National Energy Technology Laboratory incorporated candidate ionic liquids into supports and evaluated the resulting materials for membrane performance. Initial results have been very promising with carbon dioxide permeabilities as high as 950 barrers and significant improvements in carbon dioxide/hydrogen selectivity over conventional polymers at 37C and at elevated temperatures. Results include a comparison of the performance of several ionic liquids and a number of supports as well as a discussion of innovative fabrication techniques currently under development.

  1. In situ ionic-liquid-dispersive liquid-liquid microextraction of Sudan dyes from liquid samples.

    PubMed

    Xu, Bo; Song, Daqian; Wang, Yuanpeng; Gao, Yan; Cao, Bocheng; Zhang, Hanqi; Sun, Ying

    2014-08-01

    In situ ionic-liquid-dispersive liquid-liquid microextraction was introduced for extracting Sudan dyes from different liquid samples followed by detection using ultrafast liquid chromatography. The extraction and metathesis reaction can be performed simultaneously, the extraction time was shortened notably and higher enrichment factors can be obtained compared with traditional dispersive liquid-liquid microextraction. When the extraction was coupled with ultrafast liquid chromatography, a green, convenient, cheap, and efficient method for the determination of Sudan dyes was developed. The effects of various experimental factors, including type of extraction solvent, amount of 1-hexyl-3-methylimidazolium chloride, ratio of ammonium hexafluorophosphate to 1-hexyl-3-methylimidazolium chloride, pH value, salt concentration in sample solution, extraction time and centrifugation time were investigated and optimized for the extraction of four kinds of Sudan dyes. The limits of detection for Sudan I, II, III, and IV were 0.324, 0.299, 0.390, and 0.655 ng/mL, respectively. Recoveries obtained by analyzing the seven spiked samples were between 65.95 and 112.82%. The consumption of organic solvent (120 ?L acetonitrile per sample) was very low, so it could be considered as a green analytical method. PMID:24840862

  2. The radiation chemistry of ionic liquids: a review

    DOE PAGESBeta

    Mincher, Bruce J.; Wishart, James F.

    2014-07-03

    Ionic liquids have received increasing attention as media for radiochemical separations. Recent literature includes examinations of the efficiencies and mechanisms of the solvent extraction of lanthanides, actinides and fission products into ionic liquid solutions. For radiochemical applications, including as replacement solvents for nuclear fuel reprocessing, a thorough understanding of the radiation chemistry of ionic liquids will be required. Such an understanding can be achieved based upon a combination of steady-state radiolysis experiments coupled with post-irradiation product identification and pulse-radiolysis experiments to acquire kinetic information. These techniques allow for the elucidation of radiolytic mechanisms. This contribution reviews the current ionic liquidmore »radiation chemistry literature as it affects separations, with these considerations in mind.« less

  3. Electrophilic nitration of aromatics in ionic liquid solvents.

    PubMed

    Laali, K K; Gettwert, V J

    2001-01-12

    Potential utility of a series of 1-ethyl-3-methylimidazolium salts [emim][X] with X = OTf-, CF3COO-, and NO3- as well as [HNEtPri2][CF3COO] (protonated Hünig's base) ionic liquids were explored as solvent for electrophilic nitration of aromatics using a variety of nitrating systems, namely NH4NO3/TFAA, isoamyl nitrate/BF3.Et2O, isoamyl nitrate/TfOH, Cu(NO3)/TFAA, and AgNO3/Tf2O. Among these, NH4NO3/TFAA (with [emim][CF3COO], [emim][NO3]) and isoamyl nitrate/BF3.Et2O, isoamyl nitrate/TfOH (with [emim][OTf]) provided the best overall systems both in terms of nitration efficiency and recycling/reuse of the ionic liquids. For [NO2][BF4] nitration, the commonly used ionic liquids [emim][AlCl4] and [emim][Al2Cl7] are unsuitable, as counterion exchange and arene nitration compete. [Emim][BF4] is ring nitrated with [NO2][BF4] producing [NO2-emim][BF4] salt, which is of limited utility due to its increased viscosity. Nitration in ionic liquids is surveyed using a host of aromatic substrates with varied reactivities. The preparative scope of the ionic liquids was also extended. Counterion dependency of the NMR spectra of the [emim][X] liquids can be used to gauge counterion exchange (metathesis) during nitration. Ionic liquid nitration is a useful alternative to classical nitration routes due to easier product isolation and recovery of the ionic liquid solvent, and because it avoids problems associated with neutralization of large quantities of strong acid. PMID:11429927

  4. Recovery of Furfural from Aqueous Solution by Ionic Liquid Based Liquid–Liquid Extraction

    Microsoft Academic Search

    Yuanchao Pei; Kun Wu; Jianji Wang; Jing Fan

    2008-01-01

    Liquid–liquid extraction with imidazolium based ionic liquids ([C4mim][PF6], [C6mim][PF6], and [C8mim][PF6]) is proposed for the separation of furfural or 5-methylfurfural from aqueous solution. Factors affecting the extraction of furfural or 5-methylfurfural have been studied. It was shown that the extraction equilibria can be achieved within 30 min and the process was less affected by the factors such as volume ratio and

  5. Ionic liquids screening for desulfurization of natural gasoline by liquid–liquid extraction

    Microsoft Academic Search

    Natalya V. Likhanova; Diego Guzmán-Lucero; Eugenio A. Flores; Paloma García; Marco A. Domínguez-Aguilar; Jorge Palomeque; Rafael Martínez-Palou

    2010-01-01

    Seventy five ionic liquids (ILs) were tested as a sequestering agent of sulfured compounds in natural gasoline (NG). Desulphurization\\u000a of NG was performed by means of liquid–liquid extraction method at room temperature and atmospheric pressure. Experimental\\u000a ILs containing imidazolium, pyridinium, and ammonium cations along with organic and inorganic anions were synthesized conventionally\\u000a and under microwave and sonochemical conditions. The effect

  6. Ionic liquids enable accurate chromatographic analysis of polyelectrolytes.

    PubMed

    Kuroda, Kosuke; Ohno, Hiroyuki

    2015-06-16

    The molecular weight distribution of polyelectrolytes was determined with high performance liquid chromatography using ionic liquids as eluents, because the electrostatic repulsion among polyelectrolytes was entirely suppressed in it. A mixed sample of polycation and polyanion was also analysed to detect them independently. PMID:26040549

  7. Carbon Dioxide Separation with Supported Ionic Liquid Membranes

    SciTech Connect

    Luebke, D.R.; Ilconich, J.B.; Pennline, H.W.; Myers, C.R.

    2007-05-01

    A practical form of CO2 capture at water-gas shift conditions in the IGCC process could serve the dual function of producing a pure CO2 stream for sequestration and forcing the equilibrium-limited shift reaction to completion enriching the stream in H2. The shift temperatures, ranging from the low temperature shift condition of 260°C to the gasification condition of 900°C, limit capture options by diminishing associative interactions which favor removal of CO2 from the gas stream. Certain sorption interactions, such as carbonate formation, remain available but generally involve exceptionally high sorbent regeneration energies that contribute heavily to parasitic power losses. Carbon dioxide selective membranes need only establish an equilibrium between the gas phase and sorption states in order to transport CO2, giving them a potential energetic advantage over other technologies. Supported liquid membranes take advantage of high, liquid phase diffusivities and a solution diffusion mechanism similar to that observed in polymeric membranes to achieve superior permeabilities and selectivites. The primary shortcoming of the supported liquid membranes demonstrated in past research has been the lack of stability caused by volatilization of the transport liquid. Ionic liquids, which possess high CO2 solubility relative to light gases such as H2, are excellent candidates for this type of membrane since they have negligible vapor pressure and are not susceptible to evaporation. A study has been conducted evaluating the use of ionic liquids including 1-hexyl-3-methyl-imidazolium bis(trifuoromethylsulfonyl)imide in supported ionic liquid membranes for the capture of CO2 from streams containing H2. In a joint project, researchers at the University of Notre Dame synthesized and characterized ionic liquids, and researchers at the National Energy Technology Laboratory incorporated candidate ionic liquids into supports and evaluated the resulting materials for membrane performance. Improvements to the ionic liquid and support have allowed testing of these supported ionic liquid membranes at temperatures up to 300°C without loss of support mechanical stability or degradation of the ionic liquid. Substantial improvements in selectivity have also been observed at elevated temperature with the best membrane currently achieving optimum performance at 75°C.

  8. Recyclability of an ionic liquid for biomass pretreatment.

    PubMed

    Weerachanchai, Piyarat; Lee, Jong-Min

    2014-10-01

    This study investigated the possibility of reusing an ionic liquid for the pretreatment of biomass. The effects of lignin and water content in a pretreatment solvent on pretreatment products were examined, along with the recyclability of an ionic liquid for pretreatment. It was discovered that the presence of lignin and water within a pretreatment solvent resulted in a far less effective pretreatment process. 1-Ethyl-3-methylimidazolium acetate/ethanolamine (60/40 vol%) presents more promising properties than EMIM-AC, providing a small decrease in sugar conversion and also a small increase of lignin deposition with an increasing lignin amount in the pretreatment solvent. Deteriorations of the ionic liquid were observed from considerably low sugar conversions and lignin extraction after using the 5th and 7th batch, respectively. Furthermore, the changes of ionic liquid properties and lignin accumulation in ionic liquid were determined by analyzing their thermal decomposition behavior (TGA) and chemical functional groups (FTIR and (1)H NMR). PMID:25063976

  9. Ionic conductivity of imidazole-functionalized liquid crystal mesogens

    NASA Astrophysics Data System (ADS)

    Roddecha, Supacharee; Anthamatten, Mitchell

    2012-02-01

    Imidazole has been investigated as a novel anhydrous proton conducting functional group that could enable higher temperature operation (> 120 ^oC) of polymer electrolyte fuel cells. Its amphoteric behavior can support Grotthuss-like proton transport; however molecular mobility and a high concentration of imidazole groups are needed to achieve high ionic conductivity. Our hypothesis is that liquid crystal ordering, particularly in layered smectic phase, can facilitate formation of 2D proton transport and promote proton conductivity. We have designed and synthesized two imidazole-terminated liquid crystal mesogens, and the ionic conductivities in the liquid crystalline and isotropic states have been measured. Here we report on synthesis and characterization of diacylhydrazine liquid crystals bearing imidazole terminal groups. The proton conductivity of products is compared to pure liquid imidazole and to liquid crystal mesogens without imidazole groups.

  10. Mechanical properties and XRD of Nafion modified by 2-hydroxyethylammonium ionic liquids

    NASA Astrophysics Data System (ADS)

    Garaev, V.; Pavlovica, S.; Reinholds, I.; Vaivars, G.

    2013-12-01

    In this work, the Nafion 112 membrane impregnated with 2-hydroxyethylammonium carboxylate ionic liquids have been investigated. The used ionic liquids were 2-hydroxyethylammonium formate [HEA]F, acetate [HEA]A and lactate [HEA]L. Prepared composite membranes Nafion/ionic liquid are characterized by mechanical testing, such as tensile test and creep test. It is found that ionic liquids decrease elastic modulus and creep compliance, but do not have significant effect on the tensile strength. Also, composite membranes were studied by wide angle X-ray diffraction. All ionic liquids shift the peak maximum to the lower angle. In this work, only biodegradable ionic liquids were used for composite preparation.

  11. Morphology and charge transport in ammonium based polymerized ionic liquids

    NASA Astrophysics Data System (ADS)

    Heres, Maximilian; Minutolo, Joseph; Shamblin, Jacob; Long, Maik; Berdzinski, Stefan; Stremel, Veronika; Sangoro, Joshua

    2015-03-01

    Ionic conduction, structural dynamics and morphology in a series of ammonium based polymerized ionic liquids are investigated using broadband dielectric spectroscopy, temperature-modulated differential scanning calorimetry, and neutron as well as x-ray scattering techniques. The dielectric spectra are dominated on the low frequency regime by electrode polarization while hopping conduction is the underlying mechanism at higher frequencies. At their respective calorimetric glass transition temperatures, a strong correlation between the morphology and ionic conductivity is found. These results are discussed within the recent approaches proposed to explain the decoupling of charge transport from structural dynamics. UT/ORNL Science Alliance.

  12. Molecular ions of ionic liquids in the gas phase.

    PubMed

    Gross, Jürgen H

    2008-09-01

    Ionic liquids form neutral ion pairs (CA) upon evaporation. The softness of the gas-phase ionization of field ionization has been used to generate "molecular ions," CA(+*), of ionic liquids, most probably by neutralization of the anion. In detail, 1-ethyl-3-methylimidazolium-thiocyanate, [C(6)H(11)N(2)](+) [SCN](-), 1-butyl-3-methylimidazolium-tricyanomethide, [C(8)H(15)N(2)](+) [C(4)N(3)](-), N-butyl-3-methylpyridinium-dicyanamide, [C(10)H(16)N](+) [C(2)N(3)](-), and 1-butyl-1-methylpyrrolidinium-bis[(trifluormethyl)sulfonyl]amide, [C(9)H(20)N](+) [C(2)F(6)NO(4)S(2)](-) were used. The assignment as CA(+*) ions, which has been confirmed by accurate mass measurements and misassignments due to thermal decomposition of the ionic liquids, has been ruled out by field desorption and electrospray ionization mass spectrometry of the residues. PMID:18650101

  13. Reactions of solvated electrons with imidazolium cations in ionic liquids

    NASA Astrophysics Data System (ADS)

    Takahashi, Kenji; Sato, Toshifumi; Katsumura, Yosuke; Yang, Jinfeng; Kondoh, Takafumi; Yoshida, Yoichi; Katoh, Ryuzi

    2008-10-01

    We examined formation of solvated electrons in several ionic liquids composed of ammonium, pyrrolidinium and piperidinium cations by observing absorption spectra in the visible and near-infrared regions using pulse radiolysi. We also examined reactions of the solvated electrons with imidazolium cations in the ionic liquids. The reaction rate constants were an order of magnitude faster than the diffusion-limited rate calculated from the viscosity. The electrons before full solvation (dry electrons) reacted efficiently with the imidazolium cations. These observations suggest that the electrons in the ionic liquids can move easily before solvation. The scavenging of the dry electron by the imidazolium cation was also examined using C2-alkylated-imidazolium cations. It is found that the alkylation of imidazolium suppresses the reactivity with the dry electron.

  14. Evaluation of cation-anion interaction strength in ionic liquids.

    PubMed

    Fernandes, Ana M; Rocha, Marisa A A; Freire, Mara G; Marrucho, Isabel M; Coutinho, João A P; Santos, Luís M N B F

    2011-04-14

    Electrospray ionization mass spectrometry with variable collision induced dissociation of the isolated [(cation)(2)anion](+) and/or [(anion)(2)cation](-) ions of imidazolium-, pyridinium-, pyrrolidinium-, and piperidinium-based ionic liquids (ILs) combined with a large set of anions, such as chloride, tetrafluoroborate, hexafluorophosphate, trifluoromethanesulfonate, and bis[(trifluoromethyl)sulfonyl]imide, was used to carry out a systematic and comprehensive study on the ionic liquids relative interaction energies. The results are interpreted in terms of main influences derived from the structural characteristics of both anion and cation. On the basis of quantum chemical calculations, the effect of the anion upon the dissociation energies of the ionic liquid pair, and isolated [(cation)(2)anion](+) and/or [(anion)(2)cation](-) aggregates, were estimated and are in good agreement with the experimental data. Both experimental and computational results indicate an energetic differentiation between the cation and the anion to the ionic pair. Moreover, it was found that the quantum chemical calculations can describe the trend obtained for the electrostatic cation-anion attraction potential. The impact of the cation-anion interaction strengths in the surface tension of ionic liquids is further discussed. The surface tensions dependence on the cation alkyl chain length, and on the anion nature, follows an analogous pattern to that of the relative cation-anion interaction energies determined by mass spectrometry. PMID:21425809

  15. Preparation of microfibers from wood/ionic liquid solutions.

    PubMed

    Polaskova, Martina; Cermak, Roman; Verney, Vincent; Ponizil, Petr; Commereuc, Sophie; Gomes, Margarida F Costa; Padua, Agilio A H; Mokrejs, Pavel; Machovsky, Michal

    2013-01-30

    Two types of ionic liquids, 1-ethyl-3-methylimidazolim acetate and 1-ethyl-3-methylimidazolium lactate, were employed for the direct processing of pine wood into microfibers. The concentration of 5 wt.% of wood in ionic liquids was rated as the most appropriate for electrospinning. The fibers were electrospun into the collector water bath. The final structure varied from individual microfibers to fiber bundles. It was demonstrated that 1-ethyl-3-methylimidazolium lactate is a powerful solvent and provides the direct transformation of pristine pine wood into the non-wovens. PMID:23218285

  16. Use of Ionic Liquids for ?-Conjugated Polymer Electrochemical Devices

    NASA Astrophysics Data System (ADS)

    Lu, Wen; Fadeev, Andrei G.; Qi, Baohua; Smela, Elisabeth; Mattes, Benjamin R.; Ding, Jie; Spinks, Geoffrey M.; Mazurkiewicz, Jakub; Zhou, Dezhi; Wallace, Gordon G.; MacFarlane, Douglas R.; Forsyth, Stewart A.; Forsyth, Maria

    2002-08-01

    ?-Conjugated polymers that are electrochemically cycled in ionic liquids have enhanced lifetimes without failure (up to 1 million cycles) and fast cycle switching speeds (100 ms). We report results for electrochemical mechanical actuators, electrochromic windows, and numeric displays made from three types of ?-conjugated polymers: polyaniline, polypyrrole, and polythiophene. Experiments were performed under ambient conditions, yet the polymers showed negligible loss in electroactivity. These performance advantages were obtained by using environmentally stable, room-temperature ionic liquids composed of 1-butyl-3-methyl imidazolium cations together with anions such as tetrafluoroborate or hexafluorophosphate.

  17. Tuning the ionic conductivity in protic polymerized ionic liquid homo, random, and block copolymers

    NASA Astrophysics Data System (ADS)

    Evans, Christopher; Segalman, Rachel; UCSB Team

    2015-03-01

    Proton conducting membranes are of interest for a number of energy applications including use in fuel cells and artificial photosynthesis systems. We have synthesized a new class of protic polymerized ionic liquids (PILs) based on imidazolium cations which exhibit high conductivities in the solid state. In contrast to previous imidazolium based PILs, the ionic liquid moiety is attached via a carbon on the imidazole thus leaving the two nitrogens available to act as a proton donor/acceptor. The conductivies of these protic PILs, measured by dielectric spectroscopy, are orders of magnitude higher than the analogous non-protic PILs at a given distance above (Tg). These high conductivities are the result of a strong contribution from proton motion. A series of random and block copolymers containing the polymerized ionic liquid monomer and a non-ionic comonomer were also investigated to determine the role of comonomer on the conductivity of these materials. It was found that methyl acrylate, which has a low glass transition temperature and high dielectric constant, can result in improvements of ionic conductivity. Studies using solid state NMR are underway to understand the role of protons and mobile anions in controlling the overall conductivity of these materials.

  18. Energy Efficient Electrochromic Windows Incorporating Ionic Liquids

    SciTech Connect

    Cheri Boykin; James Finley; Donald Anthony; Julianna Knowles; Richard Markovic; Michael Buchanan; Mary Ann Fuhry; Lisa Perrine

    2008-11-30

    One approach to increasing the energy efficiency of windows is to control the amount of solar radiation transmitted through a window by using electrochromic technology. What is unique about this project is that the electrochromic is based on the reduction/oxidation reactions of cathodic and anodic organic semi-conducting polymers using room temperature ionic liquids as ion transport electrolytes. It is believed that these types of coatings would be a lower cost alternative to traditional all inorganic thin film based electrochromic technologies. Although there are patents1 based on the proposed technology, it has never been reduced to practice and thoroughly evaluated (i.e. durability and performance) in a window application. We demonstrate that by using organic semi-conductive polymers, specific bands of the solar spectrum (specifically visible and near infrared) can be targeted for electrochemical variable transmittance responsiveness. In addition, when the technology is incorporated into an insulating glass unit, the energy parameters such as the solar heat gain coefficient and the light to solar gain ratio are improved over that of a typical insulating glass unit comprised of glass with a low emissivity coating. A minimum of {approx}0.02 quads of energy savings per year with a reduction of carbon emissions for electricity of {approx}320 MKg/yr benefit is achieved over that of a typical insulating glass unit including a double silver low-E coating. Note that these values include a penalty in the heating season. If this penalty is removed (i.e. in southern climates or commercial structures where cooling is predominate year-round) a maximum energy savings of {approx}0.05 quad per year and {approx}801 MKg/yr can be achieved over that of a typical insulating glass unit including a double silver low-E coating. In its current state, the technology is not durable enough for an exterior window application. The primary downfall is that the redox chemistry fails to recover to a bleached state upon exposure to heat and solar radiation while being cycled over time from the bleached to the dark state. Most likely the polymers are undergoing degradation reactions which are accelerated by heat and solar exposure while in either the reduced or oxidized states and the performance of the polymers is greatly reduced over time. For this technology to succeed in an exterior window application, there needs to be more work done to understand the degradation of the polymers under real-life application conditions such as elevated temperatures and solar exposure so that recommendations for improvements in to the overall system can be made. This will be the key to utilizing this type of technology in any future real-life applications.

  19. Charge Transport and Glassy Dynamics in Ionic Liquids

    SciTech Connect

    Sangoro, Joshua R [ORNL; Kremer, Friedrich [University of Leipzig

    2012-01-01

    Ionic liquids (ILs) exhibit unique features such as low melting points, low vapor pressures, wide liquidus temperature ranges, high thermal stability, high ionic conductivity, and wide electrochemical windows. As a result, they show promise for use in variety of applications: as reaction media, in batteries and supercapacitors, in solar and fuel cells, for electrochemical deposition of metals and semiconductors, for protein extraction and crystallization, and many others. Because of the ease with which they can be supercooled, ionic liquids offer new opportunities to investigate long-standing questions regarding the nature of the dynamic glass transition and its possible link to charge transport. Despite the significant steps achieved from experimental and theoretical studies, no generally accepted quantitative theory of dynamic glass transition to date has been capable of reproducing all the experimentally observed features. In this Account, we discuss recent studies of the interplay between charge transport and glassy dynamics in ionic liquids as investigated by a combination of several experimental techniques including broadband dielectric spectroscopy, pulsed field gradient nuclear magnetic resonance, dynamic mechanical spectroscopy, and differential scanning calorimetry. Based on EinsteinSmoluchowski relations, we use dielectric spectra of ionic liquids to determine diffusion coefficients in quantitative agreement with independent pulsed field gradient nuclear magnetic resonance measurements, but spanning a broader range of more than 10 orders of magnitude. This approach provides a novel opportunity to determine the electrical mobility and effective number density of charge carriers as well as their types of thermal activation from the measured dc conductivity separately. We also unravel the origin of the remarkable universality of charge transport in different classes of glass-forming ionic liquids.

  20. Characterization of an iodine-based ionic liquid ion source and studies on ion fragmentation

    E-print Network

    Fedkiw, Timothy Peter

    2010-01-01

    Electrosprays are a well studied source of charged droplets and ions. A specific subclass is the ionic liquid ion source (ILIS), which produce ion beams from the electrostatically stressed meniscus of ionic liquids. ILIS ...

  1. Toward advanced ionic liquids. Polar, enzyme-friendly solvents for biocatalysis

    Microsoft Academic Search

    Johnathan Gorke; Friedrich Srienc; Romas Kazlauskas

    2010-01-01

    Ionic liquids, also called molten salts, are mixtures of cations and anions that melt below 100°C. Typical ionic liquids are\\u000a dialkylimidazolium cations with weakly coordinating anions such as (MeOSO3) or (PF6). Advanced ionic liquids such as choline citrate have biodegradable, less expensive, and less toxic anions and cations. Deep\\u000a eutectic solvents are also included in the advanced ionic liquids. Deep

  2. Lubrication of Steel\\/Steel Contacts by Choline Chloride Ionic Liquids

    Microsoft Academic Search

    S. D. A. Lawes; S. V. Hainsworth; P. Blake; K. S. Ryder; A. P. Abbott

    2010-01-01

    There is a growing interest in the use of ionic liquids to provide lubrication for challenging contacts. This study is an\\u000a initial assessment of the application of two ionic liquids based on choline chloride cations to be used as ionic liquid lubricants\\u000a for engineering contacts, in this case steel on steel. These ionic liquids, termed ethaline and reline, have anions

  3. Oxidation desulfurization of fuel using pyridinium-based ionic liquids as phase-transfer catalysts

    Microsoft Academic Search

    Dishun Zhao; Yanan Wang; Erhong Duan; Juan Zhang

    2010-01-01

    In this work, several ionic liquids based on pyridinium cations are prepared. The ionic liquids are employed as phase-transfer catalysts (PTCs) for phase-transfer catalytic oxidation of dibenzothiophene (DBT) dissolved in n-octane. The partition coefficients of DBT between ionic liquids and n-octane are investigated. Then H2O2–formic acid is used as an oxidant and ionic liquids are used as PTCs. The reaction

  4. Thermodynamics of micellization of imidazolium ionic liquids in aqueous solutions.

    PubMed

    ?uczak, Justyna; Jungnickel, Christian; Joskowska, Monika; Thöming, Jorg; Hupka, Jan

    2009-08-01

    The structural similarity between some ionic liquids (ILs) and ionic surfactants, indicates that ILs are expected to exhibit surface adsorption and aggregation properties. The Krafft temperature and the temperature dependence of the critical micelle concentration (CMC) were determined for four imidazolium ionic liquids with varying chain length by measuring concentration dependence of electrical conductivity at different temperatures. The magnitude of the thermodynamic parameters of the micelle formation provide valuable information about the driving force of micellization of these compounds, therefore, the parameters of these chemicals were estimated from the degree of ionization, and the CMC. The thermodynamic parameters were correlated to directly measured values using isothermal titration calorimetry (ITC). It was found that the long-chained imidazolium ILs show similar thermodynamic characteristics as traditional cationic surfactants, whereas the Krafft temperature was shown to be lower than that of traditional cationic surfactants of similar chain length. PMID:19394951

  5. Ionic liquids as potential carriers of low viscosity magnetorheological fluids

    NASA Astrophysics Data System (ADS)

    Guerrero-Sanchez, Carlos; Ortiz-Alvarado, Armando; Schubert, Ulrich S.

    2009-03-01

    Based on the latest investigations on the formulation of new magneto-rheological fluids, it is envisioned that the use of ionic liquids as carriers of magneto-rheological fluids will open new possibilities of applications for these smart fluids due to the fact that their physical and chemical properties can be fine-tuned in a broad range. This contribution addresses one potentially important advantage of magneto-rheological fluids which use ionic liquids as novel carriers. In connection with this, magneto-rheological fluids with a low viscosity in the off-state without compromising other properties of the formulations (e. g., sedimentation of the dispersed magnetic particles, liquid state of the carriers in a broad range of temperatures) are often required for specific applications. In this regard, ionic liquids of low viscosity can be very useful in the development of such magneto-rheological fluids. Thus, this contribution reports on the magnetorheological properties of iron(II, III) oxide particles dispersed in the ionic liquid 1-ethyl-3-methylimidazolium thiocyanate (a low viscosity ionic liquid) in the temperature range from 20 °C to 80 °C. The experimental results have revealed that the apparent viscosity of the dispersion slightly changes with the temperature when a constant magnetic field is applied and its value mainly depends on the shear rate and the strength of the magnetic field. The viscosity of the dispersion remains practically unmodified with both the temperature and the magnetic field intensity as the magnetic saturation of the material is reached; in this regime the viscosity will only depend on the applied shear rate. In contrast, the yield stress values of the dispersion as well as the corresponding shear stress vs. shear rate curves have shown an inverse behavior with temperature for a constant magnetic field.

  6. Benzene solubility in ionic liquids: working toward an understanding of liquid clathrate formation.

    PubMed

    Pereira, Jorge F B; Flores, Luis A; Wang, Hui; Rogers, Robin D

    2014-11-17

    The solubility of benzene in 15 imidazolium, pyrrolidinium, pyridinium, and piperidinium ionic liquids has been determined; the resulting, benzene-saturated ionic liquid solutions, also known as liquid clathrates, were examined with (1) H and (19) F nuclear magnetic resonance spectroscopy to try and understand the molecular interactions that control liquid clathrate formation. The results suggest that benzene interacts primarily with the cation of the ionic liquid, and that liquid clathrate formation (and benzene solubility) is controlled by the strength of the cation-anion interactions, that is, the stronger the cation-anion interaction, the lower the benzene solubility. Other factors that were determined to be important in the final amount of benzene in any given liquid clathrate phase included attractive interactions between the anion and benzene (when significant), and larger steric or free volume demands of the ions, both of which lead to greater benzene solubility. PMID:25297708

  7. A Ionic Liquid-Channel Field Effect Transistor

    Microsoft Academic Search

    Stephanie Anne Gajar

    1992-01-01

    A theoretical and experimental study was carried out on a new microfabricated device, an ionic liquid-channel field-effect transistor (ILCFET). The ILCFET resembles a metal-oxide-semiconductor field-effect transistor (MOSFET) except that the current flowing from the source to the drain is carried in thin channels by ions of a liquid electrolyte. Both have an electric field, transverse to the current flow, induced

  8. The use of ionic liquids based on choline chloride for metal deposition: A green alternative?

    Microsoft Academic Search

    Kurt Haerens; Edward Matthijs; Andrzej Chmielarz; Bart Van der Bruggen

    2009-01-01

    Ionic liquids are studied intensively for different applications. They tend to be denoted as “green solvents”, largely because of their low vapour pressure. In recent years toxicity and biotoxicity of ionic liquids have also been investigated, which proved that not all of these are “green”. In this paper the use of ionic liquids based on choline chloride and ethylene glycol

  9. Solubility and Aggregation of Charged Surfactants in Ionic Liquids Lang G. Chen and Harry Bermudez*

    E-print Network

    Solubility and Aggregation of Charged Surfactants in Ionic Liquids Lang G. Chen and Harry Bermudez Supporting Information ABSTRACT: Room-temperature ionic liquids (ILs) exhibit a unique set of properties between solutes and IL solvents. INTRODUCTION Room-temperature ionic liquids (ILs), organic salts

  10. Solvent extraction of rare-earth ions based on functionalized ionic liquids

    SciTech Connect

    Sun, Xiaoqi [ORNL; Dai, Sheng [ORNL; Luo, Huimin [ORNL

    2012-01-01

    We herein report the achievement of enhanced extractabilities and selectivities for separation of rare earth elements based on functionalized ionic liquids. This work highlights the potential of developing a comprehensive ionic liquid-based extraction strategy for rare earth elements using ionic liquids as both extractant and diluent.

  11. Revisiting potential physico-chemical hazards of ionic liquids Alpha O. Diallo,a,b

    E-print Network

    Paris-Sud XI, Université de

    1 Revisiting potential physico-chemical hazards of ionic liquids Alpha O. Diallo,a,b Christophe Len pertaining to ionic liquids. Indeed safety performance of ionic liquids relating to physico-chemical hazards- chemical hazard rating systems and their limitation in the context of overall risk evaluation, and d

  12. Phosphonium-based ionic liquids analogues and their physical properties

    Microsoft Academic Search

    M. A. Kareem; F. S. Mjalli; M. A. Hashim; I. M. Alnashef

    2010-01-01

    New ionic liquids analogues, that is, deep eutectic solvents (DESs), have been successfully synthesized. These DESs have been synthesized by the reaction of phosphonium-based salts with different hydrogen bond donors. Many of these DESs have melting temperatures lower than 100 °C. Preliminary laboratory results showed that these DESs can be used in different applications, for example, electrochemical processes, separation of

  13. Catalytic ignition of ionic liquids for propellant applications.

    PubMed

    Shamshina, Julia L; Smiglak, Marcin; Drab, David M; Parker, T Gannon; Dykes, H Waite H; Di Salvo, Roberto; Reich, Alton J; Rogers, Robin D

    2010-12-21

    In this proof of concept study, the ionic liquids, 2-hydroxyethylhydrazinium nitrate and 2-hydroxyethylhydrazinium dinitrate, ignited on contact with preheated Shell 405 (iridium supported on alumina) catalyst and energetically decomposed with no additional ignition source, suggesting a possible route to hydrazine replacements. PMID:20976311

  14. Ionic Liquid Lubrication Effects on Ceramics in a Water Environment

    Microsoft Academic Search

    B. S. Phillips; J. S. Zabinski

    2004-01-01

    Ionic liquids were studied to determine their effectiveness as boundary lubricant additives for water. The chemical and tribochemical reactions that govern their behavior were probed to understand lubrication mechanisms. Under water lubricated conditions, silicon nitride ceramics are characterized by a running-in period of high friction, during which time the surface is modified causing a dramatic decrease in friction and wear.

  15. IONIC LIQUID-CATALYZED ALKYLATION OF ISOBUTANE WITH 2-BUTENE

    EPA Science Inventory

    A detailed study of the alkylation of isobutane with 2-butene in ionic liquid media has been conducted using 1-alkyl-3-methylimidazolium halides?aluminum chloride encompassing various alkyl groups (butyl-, hexyl-, and octyl-) and halides (Cl, Br, and I) on its cations and anions,...

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

    Microsoft Academic Search

    R. G. Reddy

    2007-01-01

    The major objective of the project is to establish the feasibility of using specific ionic liquids capable of sustaining aluminum electrolysis near room temperature at laboratory and batch recirculation scales. It will explore new technologies for aluminum and other valuable metal extraction and process methods. The new technology will overcome many of the limitations associated with high temperatures processes such

  17. Method for synthesis of titanium dioxide nanotubes using ionic liquids

    DOEpatents

    Qu, Jun; Luo, Huimin; Dai, Sheng

    2013-11-19

    The invention is directed to a method for producing titanium dioxide nanotubes, the method comprising anodizing titanium metal in contact with an electrolytic medium containing an ionic liquid. The invention is also directed to the resulting titanium dioxide nanotubes, as well as devices incorporating the nanotubes, such as photovoltaic devices, hydrogen generation devices, and hydrogen detection devices.

  18. Vibrational spectroscopy and dynamics of small anions in ionic liquid solutions.

    PubMed

    Dahl, Kevin; Sando, Gerald M; Fox, Douglas M; Sutto, Thomas E; Owrutsky, Jeffrey C

    2005-08-22

    Fourier-transform infrared (FTIR) and time-resolved IR spectroscopies have been used to study vibrational band positions, vibrational energy relaxation (VER) rates, and reorientation times of anions in several ionic liquid (IL) solutions. The ILs primarily investigated are based on the 1-butyl-2,3-dimethylimidazolium ([BM(2)IM]) cation with thiocyanate (NCS-), dicyanamide (N(CN)2-), and tetrafluoroborate (BF4-) anions. Spectroscopic studies are carried out near 2000 cm-1 for the C[Triple Bond]N stretching bands of NCS- and N(CN)2- as the IL anion as well as for NCS-, N(CN)2-, and azide (N3-) anions dissolved in [BM2IM][BF4]. The VER studies of N(CN)2- are reported for the first time. VER of N3-, NCS-, and N(CN)2- is measured in normal solvents, such as N-methylformamide, to compare with the IL solutions. The spectral shifts and VER rates of the anions in IL solution are quite similar to those in polar aprotic, conventional organic solvents, i.e., dimethylsulfoxide, and significantly different than those in methanol, in which there is hydrogen bonding. Similar studies were also carried out for the anions in another IL, 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]), in which the C2 hydrogen is present. The results for the anions are similar to those in the [BM2IM] containing ILs, in which the C2 hydrogen is methyl substituted. This suggests that substituting this hydrogen has, at most, a minor effect on the degree of hydrogen bonding in the anion-IL solvation interaction based on the infrared spectra and dynamics. PMID:16164309

  19. Architecture, Assembly, and Emerging Applications of Branched Functional Polyelectrolytes and Poly(ionic liquid)s.

    PubMed

    Xu, Weinan; Ledin, Petr A; Shevchenko, Valery V; Tsukruk, Vladimir V

    2015-06-17

    Branched polyelectrolytes with cylindrical brush, dendritic, hyperbranched, grafted, and star architectures bearing ionizable functional groups possess complex and unique assembly behavior in solution at surfaces and interfaces as compared to their linear counterparts. This review summarizes the recent developments in the introduction of various architectures and understanding of the assembly behavior of branched polyelectrolytes with a focus on functional polyelectrolytes and poly(ionic liquid)s with responsive properties. The branched polyelectrolytes and poly(ionic liquid)s interact electrostatically with small molecules, linear polyelectrolytes, or other branched polyelectrolytes to form assemblies of hybrid nanoparticles, multilayer thin films, responsive microcapsules, and ion-conductive membranes. The branched structures lead to unconventional assemblies and complex hierarchical structures with responsive properties as summarized in this review. Finally, we discuss prospectives for emerging applications of branched polyelectrolytes and poly(ionic liquid)s for energy harvesting and storage, controlled delivery, chemical microreactors, adaptive surfaces, and ion-exchange membranes. PMID:26010902

  20. Perspectives on moving ionic liquid chemistry into the solid phase.

    PubMed

    Warner, Isiah M; El-Zahab, Bilal; Siraj, Noureen

    2014-08-01

    Ionic liquid (IL) chemistry has evolved over the past century, such that these organic salts have impacted virtually every area of science and engineering. In the area of chemistry, initial applications of these salts were primarily the domain of chemists or chemical engineers who desired to manipulate the properties of IL solvents for a variety of applications including tuning various chemical processes. Since then, the chemistry of these organic salts has progressed such that changing an important property of a solvent (e.g., melting point or hydrophobicity) often involves simply altering the counterion of the organic salt. It is with this simplicity in mind that we have recently embarked upon the use of such chemistry to manipulate important properties of solid-phase ionic organic materials. To differentiate this chemistry from ionic liquid chemistry, we have coined the acronym GUMBOS (group of uniform materials based on organic salts). In this perspective article, we describe and demonstrate how ionic liquid chemistry can provide distinct and sometimes unique chemistry for solid-phase applications. Solid phase properties which can be manipulated via this chemistry include, but are not limited to, magnetism, melting point, hydrophobicity, fluorescence quantum yields, nanoformulations, material aggregation, viscosity, viscoelasticity, and cytotoxicity. In addition, we discuss a few examples to demonstrate how GUMBOS chemistry, until now, has been beneficial to the general area of materials chemistry and, more broadly, to the field of analytical chemistry. We also project future applications of this technology. PMID:25017178

  1. Thiophene separation from aliphatic hydrocarbons using the 1-ethyl-3-methylimidazolium ethylsulfate ionic liquid

    Microsoft Academic Search

    Luisa Alonso; Alberto Arce; María Francisco; Ana Soto

    2008-01-01

    The ionic liquid 1-ethyl-3-methylimidazolium ethylsulfate has been tested as solvent for the separation of thiophene from aliphatic hydrocarbons. Liquid–liquid equilibrium data have been determined for ternary systems containing the ionic liquid, thiophene and C6, C7, C12 or C16 alkanes at T=298.15K. The performance of the ionic liquid as solvent in such systems has been evaluated. The experimental data were correlated

  2. Quasi-Solid State Dye-sensitized Solar Cells Based on Polyvinylpyrrolidone With Ionic Liquid

    Microsoft Academic Search

    L. Fan; S. Kang; J. Wu; S. Hao; Z. Lan; J. Lin

    2010-01-01

    A new ionic liquid polymer gel electrolyte containing 1-butyl-3-methylimidazolium iodide, polyvinylpyrrolidone, potassium iodide, and iodine has been prepared and characterized. Controlling the concentration of 1-butyl-3-methylimidazolium iodide, KI, and I2 with 0.9 M, 0.5 M, and 0.12 M, respectively, the ionic liquid polymer gel electrolyte attains the maximum ionic conductivity (at 30°C) of 2.3 mS cm. Based on the ionic liquid

  3. Morphology and Ionic Conductivity of Humidity-Responsive Polymerized Ionic Liquid Block Copolymers

    NASA Astrophysics Data System (ADS)

    Sharick, Sharon; Meek, Kelly; Ye, Yuesheng; Elabd, Yossef A.; Winey, Karen I.

    2014-03-01

    We present the ionic conductivity and morphology of humidity-responsive polymerized ionic liquid block copolymers (PIL BCPs), poly(methyl methacrylate- b-1-[2-(methacryloyloxy)ethyl]-3-butylimidazolium-X), where X is a bromide (Br) or hydroxide (OH) anion, as a function of relative humidity (RH), temperature, and PIL composition (?PIL) . PIL BCPs were characterized by in situ small-angle X-ray scattering and electrochemical impedance spectroscopy. These PIL BCPs have microphase separated morphologies and long-range order increases as ?PIL increases. Notably, ionic conductivity increases 3 to 4 orders of magnitude when RH increases from 30 to 90 percent. When ?PIL is greater than 0.37, BCP ionic conductivity approaches or exceeds that of the homopolymer, suggesting that the dynamics in PIL microdomains mimic the homopolymer and long-range order aids ion transport. Moreover, over 60 percent of the BCP is nonconductive without a penalty in ion transport. When ?PIL is less than 0.37, BCP conductivity is 1 to 2 orders of magnitude less than the homopolymer and non-conductive PMMA segments dominate ion transport, as expected. Ionic conductivities at 80 °C, 90 percent RH, are 7.6 mS/cm for the Br-containing BCP with ?PIL = 0.53 and 25.0 mS/cm for the OH-containing BCP with ?PIL = 0.50.

  4. Thermo-Rheometric Studies of New Class Ionic Liquid Lubricants

    NASA Astrophysics Data System (ADS)

    Bakhtiyarov, Sayavur; Street, Kenneth; Scheiman, Daniel; van Dyke, Alan

    2010-11-01

    Due to their specific properties, such as small volatility, nonflammability, extreme thermal stability, low melting point, wide liquid range, and good miscibility with organic materials, ionic liquids attracted particular interest in various industrial processes. Recently, the unique properties of ionic liquids caught the attention of space tribologists. The traditional lubricating materials used in space have limited lifetimes in vacuum due to the catalytic degradation on metal surfaces, high vaporization at high temperatures, dewetting, and other disadvantages. The lubricants for the space applications must have vacuum stability, high viscosity index, low creep tendency, good elastohydrodynamic and boundary lubrication properties, radiation atomic oxygen resistance, optical or infrared transparency. Unfortunately, the properties such as heat flow, heat capacity, thermogravimetric weight loss, and non-linearity in the rheological behavior of the lubricants are not studied well for newly developed systems. These properties are crucial to analyzing thermodynamic and energy dissipative aspects of the lubrication process. In this paper we will present the rheological and heat and mass transfer measurements for the ionic liquid lubricants, their mixtures with and without additive.

  5. Separation of fission products based on ionic liquids: Task-specific ionic liquids containing an aza-crown ether fragment

    SciTech Connect

    Luo, Huimin [ORNL] [ORNL; Dai, Sheng [ORNL] [ORNL; Bonnesen, Peter V [ORNL] [ORNL; Buchanan III, A C [ORNL] [ORNL

    2005-01-01

    A new class of task-specific ionic liquids (TSILs) based on the covalent attachment of imidazolium cations to a monoaza-crown ether fragment has been synthesized and characterized. The efficacy of these TSILs for the biphasic extraction of Cs(+) and Sr(2+) from aqueous solutions has been evaluated. The extraction properties of these TSILs can be influenced by the structures of the covalently attached imidazolium cations, which highlight the possibilities to enhance or tune the selectivities of crown ethers toward target ionic species through the covalent coupling with the imidazolium cations. (c) 2005 Elsevier B.V. All rights reserved.

  6. Direct Observation of Ion Distributions near Electrodes in Ionic Polymer Actuators Containing Ionic Liquids

    PubMed Central

    Liu, Yang; Lu, Caiyan; Twigg, Stephen; Ghaffari, Mehdi; Lin, Junhong; Winograd, Nicholas; Zhang, Q. M.

    2013-01-01

    The recent boom of energy storage and conversion devices, exploiting ionic liquids (ILs) to enhance the performance, requires an in-depth understanding of this new class of electrolytes in device operation conditions. One central question critical to device performance is how the mobile ions accumulate near charged electrodes. Here, we present the excess ion depth profiles of ILs in ionomer membrane actuators (Aquivion/1-butyl-2,3-dimethylimidazolium chloride (BMMI-Cl), 27??m thick), characterized directly by Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) at liquid nitrogen temperature. Experimental results reveal that for the IL studied, cations and anions are accumulated at both electrodes. The large difference in the total volume occupied by the excess ions between the two electrodes cause the observed large bending actuation of the actuator. Hence we demonstrate that ToF-SIMS experiment provides great insights on the physics nature of ionic devices. PMID:23512124

  7. Surface structure at the ionic liquid-electrified metal interface.

    PubMed

    Baldelli, Steven

    2008-03-01

    Room-temperature ionic liquids are a new class of liquids with many important uses in electrical and electrochemical devices. The liquids are composed purely of ions in the liquid state with no solvent. They generally have good electrical and ionic conductivity and are electrochemically stable. Since their applications often depend critically on the interface structure of the liquid adjacent to the electrode, a molecular level description is necessary to understanding and improving their performance. There are currently no adequate models or descriptions on the organization of the ions, in these pure ionic compounds, adjacent to the electrode surface. In normal electrolytic solutions, the organization of solvent and ions is adequately described by the Gouy-Chapman-Sterns model. However, this model is based on the same concepts as those in Debye-Huckel theory, that is a dilute electrolyte, where ions are well-separated and noninteracting. This is definitely not the situation for ionic liquids. Thus our goal was to investigate the ionic liquid-metal interface using surface-specific vibrational spectroscopy sum frequency generation, SFG. This technique can probe the metal-liquid interface without interference from the bulk electrolyte. Thus the interface is probed in situ while the electrode potential is changed. To compliment the vibrational spectroscopy, electrochemical impedance spectroscopy (EIS) is used to measure the capacitance and estimate the "double layer" thickness and the potential of zero charge (PZC). In addition, the vibrational Stark shift of CO adsorbed on the Pt electrode was measured to provide an independent measure of the "double layer" thickness. All techniques were measured as a function of applied potential to provide full description of the interface for a variety of imidazolium-based (cation) ionic liquids. The vibrational Stark shift and EIS results suggest that ions organize in a Helmholtz-like layer at the interface, where the potential drop occurs over the a range of 3-5 A from the metal surface into the liquid. Further, the SFG results imply that the "double layer" structure is potential-dependent; At potentials positive of the PZC, anions adsorbed to the surface and the imidazolium ring are repelled to orient more along the surface normal, compared with the potentials negative of the PZC, at which the cation is oriented more parallel to the surface plane and the anions are repelled from the surface. The results present a view of the ionic liquid-metal electrode interface having a very thin "double layer" structure where the ions form a single layer at the surface to screen the electrode charge. However, the results also raise many other fundamental questions as to the detailed nature of the interfacial structure and interpretations of both electrochemical and spectroscopic data. PMID:18232666

  8. Extraction of organic acids using imidazolium-based ionic liquids and their toxicity to Lactobacillus rhamnosus

    Microsoft Academic Search

    Michiaki Matsumoto; Kenji Mochiduki; Kei Fukunishi; Kazuo Kondo

    2004-01-01

    In situ extractive fermentation of lactic acid using organic solvents has already been heavily investigated. Now ionic liquids are emerging as alternative solvents for volatile organic compounds traditionally used in liquid–liquid extraction. In this paper, we examine whether imidazolium-based ionic liquids can replace conventional organic solvents in the extractive fermentation of lactate by investigating their extraction behaviors and solvent toxicity.

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

    PubMed

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

    2014-03-01

    A sensitive determination method was developed for the analysis of pyrethroid pesticide residues in tomato samples using ionic liquid-based dispersive liquid-liquid microextraction. A hydrophobic ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) and acetonitrile were used as the extraction solvent and dispersive solvent, respectively. The following experimental parameters affecting the extraction efficiency were examined: types of extraction solvent and volume of extraction solvent, types of dispersive solvent and volume of dispersive solvent and pH and ion strength of the sample solution. Under the optimum conditions, the extraction recoveries ranged from 83.9 to 96.7%. Moreover, the enrichment factors for esbiothrin, fenpropathrin and cyhalothrin were 42, 48 and 45, respectively. The calibration curves were linear with correlation coefficients ranging from 0.9997 to 0.9999 at concentrations of 0.05-1.5 µg/kg. The relative standard deviation (n = 5) was 1.7-4.5%. The limits of detection for esbiothrin, fenpropathrin and cyhalothrin were 8.1, 9.9 and 14.3 µg/kg, respectively. PMID:23519563

  10. Dissolution and depolymerization of barley starch in selected ionic liquids.

    PubMed

    Lappalainen, Katja; Kärkkäinen, Johanna; Lajunen, Marja

    2013-03-01

    Polysaccharides like starch are poorly soluble in common solvents. However, certain ionic liquids (ILs) have been found to dissolve them, although some depolymerization happens during the dissolution. Dissolution and depolymerization of barley starch in ten ionic liquids have been studied with p-TsOH as a catalyst under controlled microwave heating. Dissolution time and the extent of the depolymerization of starch, determined by using HPLC-ELSD, were specific to each IL. Dialkylimidazolium halide ILs dissolved starch fast and depolymerized it substantially producing 79-100% water-soluble starch oligomers with the average molecular weight of 1000-2000Da. 1-Ethyl-3-methylimidazolium phosphate ([EMIM][Me2PO4]) and 2-hydroxyethylammonium formate ([NH3CH2CH2OH][HCOO]) dissolved starch slowly and depolymerized it least among the tested ILs. For the slow depolymerization of starch these ILs can be considered as suitable solvents for starch modifications where its depolymerization should be avoided. PMID:23465905

  11. Reactions of Lignin Model Compounds in Ionic Liquids

    SciTech Connect

    Holladay, John E.; Binder, Joseph B.; Gray, Michel J.; White, James F.; Zhang, Z. Conrad

    2009-09-15

    Lignin, a readily available form of biomass, awaits novel chemistry for converting it to valuable aromatic chemicals. Recent work has demonstrated that ionic liquids are excellent solvents for processing woody biomass and lignin. Seeking to exploit ionic liquids as media for depolymerization of lignin, we investigated reactions of lignin model compounds in these solvents. Using Brønsted acid catalysts in 1-ethyl-3-methylimidazolium triflate at moderate temperatures, we obtained up to 11.6% yield of the dealkylation product guaiacol from the model compound eugenol and cleaved phenethyl phenyl ether, a model for lignin ethers. Despite these successes, acid catalysis failed in dealkylation of the unsaturated model compound 4-ethylguaiacol and did not produce monomeric products from organosolv lignin, demonstrating that further work is required to understand the complex chemistry of lignin depolymerization.

  12. Keggin-type polyoxometalate-based ionic liquid gels.

    PubMed

    Huang, Tianpei; Tian, Naiqin; Wu, Qingyin; Yan, Wenfu

    2015-05-27

    A series of reversible phase transformation ammonium- and phosphonium-based polyoxometalate ionic liquid (POM-IL) gels were synthesized and studied with a focus on the correlation between their physicochemical properties and their chemical structure. The products were successfully characterized by IR, UV, XRD and TG-DTA, and their ionic conductivities were measured. The Keggin-type heteropolyanion clusters decorated with long alkyl chains demonstrated a tendency to exhibit a gel state at room temperature, while all the gels transformed into liquids after heating and then recovered after cooling. With a decrease in the alkyl chain length, a significant improvement in the thermal stability and conductivity of the ammonium-based POM-IL gels can be achieved. Moreover, compared with the corresponding ammonium compound, phosphonium-based POM-IL gel was found to be more stable at high temperature and exhibited better conductivity. PMID:25947074

  13. Ionic liquid lubricants: designed chemistry for engineering applications.

    PubMed

    Zhou, Feng; Liang, Yongmin; Liu, Weimin

    2009-09-01

    This tutorial review outlines current state of the art research on ionic liquid lubricants. Ionic liquids (ILs) were first reported as very promising high-performance lubricants in 2001 and have attracted considerable attention in the field of tribology since then because of their remarkable lubrication and anti-wear capabilities as compared with lubrication oils in general use; in recent times we have seen dramatically increased interest in the topic. The review starts with a brief introduction to ILs and fluid lubrication, and then discusses in more detail the tribological properties of IL lubricants, either as lubrication oils, additives or thin films. As well as lubrication mechanisms, some current problems and potential solutions are tentatively discussed. PMID:19690739

  14. Annealing and ionic liquid gating on suspended molybdenum disulfide devices

    NASA Astrophysics Data System (ADS)

    Wang, Fenglin; Stepanov, Petr; Gray, Mason; Itkis, Mikhail; Haddon, Robert; Lau, Chun Ning

    2015-03-01

    We fabricate suspended molybdenum disulfide (MoS2) field effect transistors (FET) devices and develop an effective gas annealing technique that significantly improves device quality and increases conductance by 3-4 orders of magnitude. Temperature dependence measurements reveal two transport mechanisms: electron-phonon scattering at high temperatures and thermal activation over a gate-tunable barrier height at low temperatures. Our results suggest that transport in these devices is not limited by the substrates. Moreover, this suspended MoS2 device structure provides double surface access for ionic liquid gating. We are able to extract the dielectric constant of the ionic liquid, and the latest experimental results will be presented.

  15. Electrodeposition of magnesium film from BMIMBF 4 ionic liquid

    NASA Astrophysics Data System (ADS)

    NuLi, Yanna; Yang, Jun; Wang, Pu

    2006-09-01

    In this paper, we reported for the first time magnesium electrodeposition and dissolution processes in the ionic liquid of BMIMBF 4 with 1 M Mg(CF 3SO 3) 2 at room temperature. Our study found that complete electrochemical reoxidation of the electrodeposited magnesium film was feasible only on Ag substrate, comparing with the Pt, Ni, and stainless-steel. Scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) results showed that magnesium was found in the deposited film and the deposits were dense. The electrodeposition of magnesium on Ag substrate in the ionic liquid was considered to be a reversible process by cyclic voltammetry. Plots of peak current versus the square root of the scan rate were found to be linear, which indicates that the mass-transport process of electroactive species was mainly diffusion controlled. The diffusion coefficient D values of electroactive species were calculated from cyclic voltammetry and chronoamperometry, respectively.

  16. Solubility and aggregation of charged surfactants in ionic liquids.

    PubMed

    Chen, Lang G; Bermudez, Harry

    2012-01-17

    Room-temperature ionic liquids (ILs) exhibit a unique set of properties, leading to opportunities for numerous applications. To obtain a better understanding of IL interfaces at a molecular level, we combined charged surfactants with ILs and studied their interfacial behavior. The critical micelle concentration (cmc) of each surfactant-IL pair was determined from both solubility phase diagrams and isotherms. Because the cmc is equivalent to the solubility at the Krafft temperature, a connection between the solubility of the surfactant and the physical properties of the underlying ionic liquid was established. Interfacial energy was found to be the major factor affecting the surfactant aggregation process, although its magnitude depends strongly on the IL structure. The results here give insight into explaining the nature of self-assembly of surfactants at IL interfaces and the interaction between solutes and IL solvents. PMID:22168452

  17. Ionic liquid-induced synthesis of selenium nanoparticles

    SciTech Connect

    Langi, Bhushan [Changu Kana Thakur Research Centre, New Panvel 410 206 (India)] [Changu Kana Thakur Research Centre, New Panvel 410 206 (India); Shah, Chetan; Singh, Krishankant [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)] [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Chaskar, Atul, E-mail: achaskar@rediffmail.com [Changu Kana Thakur Research Centre, New Panvel 410 206 (India)] [Changu Kana Thakur Research Centre, New Panvel 410 206 (India); Kumar, Manmohan; Bajaj, Parma N. [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)] [Radiation and Photochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

    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.

  18. Synthesis and characterization of 5-cyanotetrazolide-based ionic liquids.

    PubMed

    Bergholz, Timm; Oelkers, Benjamin; Huber, Benedikt; Roling, Bernhard; Sundermeyer, Jörg

    2015-02-01

    New salts based on imidazolium, pyrrolidinium, phosphonium, guanidinium, and ammonium cations together with the 5-cyanotetrazolide anion [C2 N5 ](-) are reported. Depending on the nature of cation-anion interactions, characterized by XRD, the ionic liquids (ILs) have a low viscosity and are liquid at room temperature or have higher melting temperatures. Thermogravimetric analysis, cyclic voltammetry, viscosimetry, and impedance spectroscopy display a thermal stability up to 230?°C, an electrochemical window of 4.5?V, a viscosity of 25?mPa?s at 20?°C, and an ionic conductivity of 5.4 mS cm(-1) at 20?°C for the IL 1-butyl-1-methylpyrrolidinium 5-cyanotetrazolide [BMPyr][C2 N5 ]. On the basis of these results, the synthesized compounds are promising electrolytes for lithium-ion batteries. PMID:25504790

  19. Carbon films produced from ionic liquid carbon precursors

    DOEpatents

    Dai, Sheng; Luo, Huimin; Lee, Je Seung

    2013-11-05

    The invention is directed to a method for producing a film of porous carbon, the method comprising carbonizing a film of an ionic liquid, wherein the ionic liquid has the general formula (X.sup.+a).sub.x(Y.sup.-b).sub.y, wherein the variables a and b are, independently, non-zero integers, and the subscript variables x and y are, independently, non-zero integers, such that ax=by, and at least one of X.sup.+ and Y.sup.- possesses at least one carbon-nitrogen unsaturated bond. The invention is also directed to a composition comprising a porous carbon film possessing a nitrogen content of at least 10 atom %.

  20. Recycling of aluminum metal matrix composite using ionic liquids

    Microsoft Academic Search

    V. Kamavaram; D. Mantha; R. G. Reddy

    2005-01-01

    Recycling of aluminum metal matrix composite via electrolysis in ionic liquids at low-temperature was investigated. The electrolytic melt comprised of 1-butyl-3-methylimidazolium chloride (BMIC) and anhydrous AlCl3. Aluminum metal matrix composite (Duralcan®, Al-380, 20vol.% SiC) was electrochemically dissolved at the anode, and pure aluminum (>98%) was deposited on a copper cathode. The influence of experimental parameters such as concentration of electrolyte

  1. Catalytic conversion of cellulose to chemicals in ionic liquid

    Microsoft Academic Search

    Furong Tao; Huanling Song; Lingjun Chou

    2011-01-01

    A simple and effective route for the production of 5-hydroxymethyl furfural (HMF) and furfural from microcrystalline cellulose (MCC) has been developed. CoSO4 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

  2. A review of ionic liquids towards supercritical fluid applications

    Microsoft Academic Search

    Seda Keskin; Defne Kayrak-Talay; U?ur Akman; Öner Hortaçsu

    2007-01-01

    Ionic liquids (ILs), considered to be a relatively recent magical chemical due their unique properties, have a large variety of applications in all areas of the chemical industries. The areas of application include electrolyte in batteries, lubricants, plasticizers, solvents and catalysis in synthesis, matrices for mass spectroscopy, solvents to manufacture nano-materials, extraction, gas absorption agents, etc. Non-volatility and non-flammability are

  3. Lubrication of Inconel 600 with ionic liquids at high temperature

    Microsoft Academic Search

    A. E. Jiménez; M. D. Bermúdez; P. Iglesias

    2009-01-01

    The friction and wear behavior of Inconel 600 against AISI 52100 steel have been studied in the presence of three ionic liquid (IL) lubricants, two imidazolium derivatives, 1-methyl-3-octylimidazolium tetrafluoroborate (L108) and 1-methyl-3-hexylimidazolium hexafluorophosphate (L-P106), and the quaternary ammonium chloride AMMOENG™101 (AM-101), and compared with a mineral base oil at room temperature. The IL lubricants have been studied at high temperature.

  4. Predicting mobility of alkylimidazolium ionic liquids in soils

    Microsoft Academic Search

    Wojciech Mrozik; Christian Jungnickel; Tomasz Ciborowski; William Robert Pitner; Jolanta Kumirska; Zbigniew Kaczy?ski; Piotr Stepnowski

    2009-01-01

    Background, aim, and scope  Ionic liquids (ILs) are a new class of alternative solvents that make ideal non-volatile media for a variety of industrial\\u000a processes such as organic synthesis and biocatalysis, as alternative electrolytes, as phases and phase modifications in separation\\u000a techniques, and as alternative lubricants. Once the large-scale implementation of ILs begins, the industrial application will\\u000a follow. In view of

  5. MINOR ACTINIDE SEPARATIONS USING ION EXCHANGERS OR IONIC LIQUIDS

    SciTech Connect

    Hobbs, D.; Visser, A.; Bridges, N.

    2011-09-20

    This project seeks to determine if (1) inorganic-based ion exchange materials or (2) electrochemical methods in ionic liquids can be exploited to provide effective Am and Cm separations. Specifically, we seek to understand the fundamental structural and chemical factors responsible for the selectivity of inorganic-based ion-exchange materials for actinide and lanthanide ions. Furthermore, we seek to determine whether ionic liquids can serve as the electrolyte that would enable formation of higher oxidation states of Am and other actinides. Experiments indicated that pH, presence of complexants and Am oxidation state exhibit significant influence on the uptake of actinides and lanthanides by layered sodium titanate and hybrid zirconium and tin phosphonate ion exchangers. The affinity of the ion exchangers increased with increasing pH. Greater selectivity among Ln(III) ions with sodium titanate materials occurs at a pH close to the isoelectric potential of the ion exchanger. The addition of DTPA decreased uptake of Am and Ln, whereas the addition of TPEN generally increases uptake of Am and Ln ions by sodium titanate. Testing confirmed two different methods for producing Am(IV) by oxidation of Am(III) in ionic liquids (ILs). Experimental results suggest that the unique coordination environment of ionic liquids inhibits the direct electrochemical oxidation of Am(III). The non-coordinating environment increases the oxidation potential to a higher value, while making it difficult to remove the inner coordination of water. Both confirmed cases of Am(IV) were from the in-situ formation of strong chemical oxidizers.

  6. Succinoylation of cellulose catalyzed with iodine in ionic liquid

    Microsoft Academic Search

    C. F. Liu; A. P. Zhang; W. Y. Li; F. X. Yue; R. C. Sun

    2010-01-01

    In present study, succinoylation of sugarcane bagasse cellulose was performed with succinic anhydride (SA) using iodine as a catalyst in solvent system containing ionic liquid (IL), 1-butyl-3-methylimidazolium chloride ([C4mim]Cl), and dimethylsulfoxide (DMSO). The results showed that all succinylated cellulosic derivatives had the degree of substitution (DS) in the range of 0.56–1.54, which noticeably increased compared with the products without any

  7. Novel all-cellulose ecocomposites prepared in ionic liquids

    Microsoft Academic Search

    Qiang Zhao; Richard C. M. Yam; Baoqing Zhang; Yingkui Yang; Xinjian Cheng; Robert K. Y. Li

    2009-01-01

    In this study, a kind of novel all-cellulose ecocomposites based on cellulose and rice husk (RH) has been prepared by using\\u000a green solvent, ionic liquid (IL), as processing medium. Due to the presence of the RH, these ecocomposites also contain an\\u000a inorganic component, silica. The content and distribution of the silica in the ecocomposite have been investigated by energy\\u000a dispersive

  8. Electromechanical performance and membrane stability of novel ionic polymer transducers constructed in the presence of ionic liquids

    NASA Astrophysics Data System (ADS)

    Duncan, Andrew J.; Leo, Donald J.; Long, Timothy E.; Akle, Barbar J.; Park, Jong K.; Moore, Robert B.

    2009-03-01

    Ionic polymer transducers (IPT) are a class of devices that leverage electroactive polymers (EAP), specifically electrolyte-swollen ionomeric membranes, to perform energy conversions. Energy transformation from input to output is referred to as transduction and occurs between the electrical and mechanical domains. The present study expands on IPT investigations with a novel series of sulfonated polysulfones (sBPS), with specific interest in the effect of polymer topology on actuator performance. A hydrophilic ionic liquid was combined with a series of sBPS through a casting method to create hydrated membranes that contained target uptakes (f) of the diluent. The ionic liquid's hydrophilic, yet organic nature raised the issue of its degree of compatibility and miscibility with the microphase separated domains of the host ionomeric membrane. Initial studies of the ionomer - ionic liquid morphology were performed with synchrotron small angle X-ray scattering (SAXS). The effective plasticization of the membranes was identified with dynamic mechanical analysis (DMA) in terms of varied storage modulus and thermal transitions with ionic liquid uptake. Electrical impedance spectroscopy (EIS) was employed to quantify the changes in ionic conductivity for each sBPS ionomer across a range of uptake. Combined results from these techniques implied that the presence of large amounts of ionic liquid swelled the hydrophilic domains of the ionomer and greatly increased the ionic conductivity. Decreases in storage modulus and the glass transition temperature were proportional to one another but of a lesser magnitude than changes in conductivity. The present range of ionic liquid uptake for sBPS was sufficient to identify the critical uptake (fc) for three of the four ionomers in the series. Future work to construct IPTs with these components will use the critical uptake as a minimum allowable content of ionic liquid to optimize the balance of electrical and mechanical properties for the device components.

  9. Hydrogen production in aromatic and aliphatic ionic liquids.

    PubMed

    Dhiman, Surajdevprakash B; Goff, George S; Runde, Wolfgang; Laverne, Jay A

    2013-06-01

    The radiolytic production of molecular hydrogen in the ionic liquids N-trimethyl-N-butylammonium bis(trifluoromethanesulfonyl)imide ([N1114][Tf2N]) and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([emim][Tf2N]) has been examined with ?-rays, 2-10 MeV protons, and 5-20 MeV helium ions to determine the functional dependence of the yield on particle track structure. Molecular hydrogen is the dominant gaseous radiolysis product from these ionic liquids, and the yields with ?-rays are 0.73 and 0.098 molecules per 100 eV of energy absorbed for [N1114][Tf2N] and [emim][Tf2N], respectively. These low yields are consistent with the relative insensitivity of most aromatic compounds to radiation. However, the molecular hydrogen yields increase considerably on going from ?-rays to protons to helium ions with [emim][Tf2N] while they remain essentially constant for [N1114][Tf2N]. FTIR and UV-vis spectroscopic studies show slight degradation of the ionic liquids with radiation. PMID:23675989

  10. The solvation structures of cellulose microfibrils in ionic liquids

    SciTech Connect

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

    2011-01-01

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

  11. Separation of carbon dioxide from nitrogen or methane by supported ionic liquid membranes (SILMs): influence of the cation charge of the ionic liquid.

    PubMed

    Hojniak, Sandra D; Khan, Asim Laeeq; Hollóczki, Oldamur; Kirchner, Barbara; Vankelecom, Ivo F J; Dehaen, Wim; Binnemans, Koen

    2013-12-01

    Supported ionic liquid membranes (SILMs) are promising tools for the separation of carbon dioxide from other gases. In this paper, new imidazolium, pyrrolidinium, piperidinium, and morpholinium ionic liquids with a triethylene glycol side chain and tosylate anions, as well as their symmetrical dicationic analogues, have been synthesized and incorporated into SILMs. The selectivities for CO2/N2 and CO2/CH4 separations have been measured. The selectivities exhibited by the dicationic ionic liquids are up to two times higher than the values of the corresponding monocationic ionic liquids. Quantum chemical calculations have been used to investigate the difference in the interaction of carbon dioxide with monocationic and dicationic ionic liquids. The reason for the increased gas separation selectivity of the dicationic ionic liquids is two-fold: (1) a decrease in permeance of nitrogen and methane through the ionic liquid layer, presumably due to their less favorable interactions with the gases, while the permeance of carbon dioxide is reduced much less; (2) an increase in the number of interaction sites for the interactions with the quadrupolar carbon dioxide molecules in the dicationic ionic liquids, compared to the monocationic analogues. PMID:24199938

  12. Electronically and ionically conductive gels of ionic liquids and charge-transfer tetrathiafulvalene-tetracyanoquinodimethane.

    PubMed

    Mei, Xiaoguang; Ouyang, Jianyong

    2011-09-01

    Electronically and ionically conductive gels were fabricated by mixing and mechanically grinding neutral tetrathiafulvalene (TTF) and tetracyanoquinodimethane (TCNQ) in ionic liquids (ILs) like 3-ethyl-1-methylimidazolium dicyanoamide (EMIDCA), 1-ethyl-3-methylimidazolium thiocyanate (EMISCN), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMITf(2)N), trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)imide (P(14,6,6,6)Tf(2)N), and methyl-trioctylammonium bis(trifluoromethylsulfonyl)imide (MOATf(2)N). Charge-transfer TTF-TCNQ crystallites were generated during the mechanical grinding as indicated by the UV-visibile-near-infrared (UV-vis-NIR) absorption spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction. The charge-transfer TTF-TCNQ crystallites have a needle-like shape. They form solid networks to gelate the ILs. The gel behavior is confirmed by the dynamic mechanical measurements. It depends on both the anions and cations of the ILs. In addition, when 1-methyl-3-butylimidazolium tetrafluoroborate (BMIBF(4)) and 1-methyl-3-propylimidazolium iodide (PMII) were used, the TTF-TCNQ/IL mixtures did not behave as gels. The TTF-TCNQ/IL gels are both electronically and ionically conductive, because the solid phase formed by the charge-transfer TTF-TCNQ crystallites is electronically conductive, while the ILs are ionically conductive. The gel formation is related to needle-like charge-transfer TTF-TCNQ cyrstallites and the ?-? and Coulombic interactions between TTF-TCNQ and ILs. PMID:21800893

  13. Influence of the Electrolyte Film Thickness on Charge Dynamics of Ionic Liquids in Ionic Electroactive Devices

    PubMed Central

    Lin, Junhong; Liu, Yang; Zhang, Q.M.

    2012-01-01

    Developing advanced ionic electroactive devices such as ionic actuators and supercapacitors requires the understanding of ionic diffusion and drifting processes, which depend on the distances over which the ions travel, in these systems. The charge dynamics of [C4mim][PF6] ionic liquid films and Aquivion membranes with 40 wt% [C2mim][TfO] were investigated over a broad film thickness (d) range. It was found that the double layer charging time ?DL follows the classic model ?DL = ?Dd/(2D) very well, where D is the diffusion coefficient and ?D the Debye length. In the longer time regimes (t ? ?DL) where diffusion dominates, the charge dynamics become voltage dependent. For low applied voltage, the later stage charge process seems to follow the d2 dependence. However, at high voltages (> 0.5 V) in which significant device responses occur, the charging process does not show d2 dependence so that ?diff = d2/(4D), corresponding to the ion diffusion from the bulk region, was not observed. PMID:22423148

  14. Hg? removal from flue gas by ionic liquid/H?O?.

    PubMed

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

    2014-09-15

    1-Alkyl-3-methylimidazolium chloride ionic liquids ([Cnmim] Cl, n=4, 6, 8) were prepared. The ionic liquid was then mixed with hydrogen peroxide (H2O2) to form an absorbent. The Hg(0) removal performance of the absorbent was investigated in a gas/liquid scrubber using simulated flue gas. It was found that the ionic liquid/H2O2 mixture was an excellent absorbent and could be used to remove Hg(0) from flue gas. When the mass ratio of H2O2 to ionic liquid was 0.5, the absorbent showed high Hg(0) removal efficiency (up to 98%). The Hg(0) removal efficiency usually increased with the absorption temperature, while decreased with the increase of alkyl chain length in ionic liquid molecule. The Hg(0) removal mechanism involved with Hg(0) oxidation by H2O2 and Hg(2+) transfer from aqueous phase to ionic liquid phase. PMID:25240646

  15. Synthesis and characterization of new class of ionic liquids containing phenolate anion

    SciTech Connect

    Lethesh, Kallidanthiyil Chellappan, E-mail: lethesh.chellappan@petronas.com.my [PETRONAS Ionic Liquids Center, Universiti Teknologi PETRONAS (Malaysia); Wilfred, Cecilia Devi; Taha, M. F. [Department of Chemical Engineering, Universiti Teknologi PETRONAS (Malaysia); Thanabalan, M. [Fundamental and Applied Sciences, Universiti Teknologi PETRONAS (Malaysia)

    2014-10-24

    In these manuscript novel ionic liquids containing a new class of 'phenolate' anions was synthesized and characterized. 1-methylmidazole with different alkyl chains such as butyl, hexyl and octyl groups was used as the cationic part. All the ionic liquids were obtained as liquids at room temperature. The synthesized ionic liquids were characterized using {sup 1}H NMR and {sup 13}C NMR spectroscopy. The thermal stability of the ionic liquids was studied using thermo gravimetric analysis (TGA). The effect of temperature on the density and viscosity of the ionic liquids were studied over a temperature range from 293.15 K to 373.15K at atmospheric pressure. From the experimental values of density, the molecular volume, standard molar entropy and the lattice energy of the ionic liquids were calculated.

  16. Nitrile-functionalized pyridinium, pyrrolidinium, and piperidinium ionic liquids.

    PubMed

    Lethesh, Kallidanthiyil Chellappan; Van Hecke, Kristof; Van Meervelt, Luc; Nockemann, Peter; Kirchner, Barbara; Zahn, Stefan; Parac-Vogt, Tatjana N; Dehaen, Wim; Binnemans, Koen

    2011-07-01

    Two series of 1-alkylpyridinium and N-alkyl-N-methylpiperidinium ionic liquids functionalized with a nitrile group at the end of the alkyl chain have been synthesized. Structural modifications include a change of the alkyl spacer length between the nitrile group and the heterocycle of the cationic core, as well as adding methyl or ethyl substituents on different positions of the pyridinium ring. The anions are the bromide and the bis(trifluoromethylsulfonyl)imide ion. All the bis(trifluoromethylsulfonyl)imide salts as well as the bromide salts with a long alkyl spacer were obtained as viscous liquids at room temperature, but some turned out to be supercooled liquids. In addition, pyrrolidinium and piperidinium ionic liquids with two nitrile functions attached to the heterocyclic core have been prepared. The crystal structures of seven pyridinium bis(trifluoromethylsulfonyl)imide salts are reported. Quantum chemical calculations have been performed on model cations and ion pairs with the bis(trifluoromethylsulfonyl)imide anion. A continuum model has been used to take solvation effects into account. These calculations show that the natural partial charge on the nitrogen atom of the nitrile group becomes more negative when the length of the alkyl spacer between the nitrile functional group and the heterocyclic core of the cation is increased. Methyl or methoxy substituents on the pyridinium ring slightly increase the negative charge on the nitrile nitrogen atom due to their electron-donating abilities. The position of the substituent (ortho, meta, or para) has only a very minor effect on the charge of the nitrogen atom. The (15)N NMR spectra of the bis(trifluoromethylsulfonyl)imide ionic liquids were recorded with the nitrogen-15 nucleus at its natural abundance. The chemical shift of the (15)N nucleus of the nitrile nitrogen atom could be correlated with the calculated negative partial charge on the nitrogen atom. PMID:21609018

  17. Phosphonium chloromercurate room temperature ionic liquids of variable composition.

    PubMed

    Metlen, Andreas; Mallick, Bert; Murphy, Richard W; Mudring, Anja-Verena; Rogers, Robin D

    2013-12-16

    The system trihexyl(tetradecyl)phosphonium ([P66614]Cl)/mercury chloride (HgCl2) has been investigated by varying the stoichiometric ratios from 4:1 to 1:2 (25, 50, 75, 100, 150, and 200 mol % HgCl2). All investigated compositions turn out to give rise to ionic liquids (ILs) at room temperature. The prepared ionic liquids offer the possibility to study the structurally and compositionally versatile chloromercurates in a liquid state at low temperatures in the absence of solvents. [P66614]2[HgCl4] is a simple IL with one discrete type of anion, while [P66614]{HgCl3} (with {} indicating a polynuclear arrangement) is an ionic liquid with a variety of polyanionic species, with [Hg2Cl6](2-) apparently being the predominant building block. [P66614]2[Hg3Cl8] and [P66614][Hg2Cl5] appear to be ILs at ambient conditions but lose HgCl2 when heated in a vacuum. For the liquids with the compositions 4:1 and 4:3, more than two discrete ions can be evidenced, namely, [P66614](+), [HgCl4](2-), and Cl(-) and [P66614](+), [HgCl4](2-), and the polynuclear {HgCl3}(-), respectively. The different stoichiometric compositions were characterized by (199)Hg NMR, Raman- and UV-vis spectroscopy, and cyclic voltammetry, among other techniques, and their densities and viscosities were determined. The [P66614]Cl/HgCl2 system shows similarities to the well-known chloroaluminate ILs (e.g., decrease in viscosity with increasing metal content after addition of more than 0.5 mol of HgCl2/mol [P66614]Cl, increasing density with increasing metal content, and the likely formation of polynuclear/polymeric/polyanionic species) but offer the advantage that they are air and water stable. PMID:24274831

  18. Homogeneous Liquid–Liquid Extraction of Rare Earths with the Betaine—Betainium Bis(trifluoromethylsulfonyl)imide Ionic Liquid System

    PubMed Central

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

    2013-01-01

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

  19. Application of Ionic Liquids in High Performance Reversed-Phase Chromatography

    PubMed Central

    Wang, Ye; Tian, Minglei; Bi, Wentao; Row, Kyung Ho

    2009-01-01

    Ionic liquids, considered “green” chemicals, are widely used in many areas of analytical chemistry due to their unique properties. Recently, ionic liquids have been used as a kind of novel additive in separation and combined with silica to synthesize new stationary phase as separation media. This review will focus on the properties and mechanisms of ionic liquids and their potential applications as mobile phase modifier and surface-bonded stationary phase in reversed-phase high performance liquid chromatography (RP-HPLC). Ionic liquids demonstrate advantages and potential in chromatographic field. PMID:19582220

  20. Ionic liquid-based stable nanofluids containing gold nanoparticles.

    PubMed

    Wang, Baogang; Wang, Xiaobo; Lou, Wenjing; Hao, Jingcheng

    2011-10-01

    A one-phase and/or two-phase method were used to prepare the stable ionic liquid-based nanofluids containing same volume fraction but different sizes or surface states of gold nanoparticles (Au NPs) and their thermal conductivities were investigated in more detail. Five significant experiment parameters, i.e. temperature, dispersion condition, particle size and surface state, and viscosity of base liquid, were evaluated to supply experimental explanations for heat transport mechanisms. The conspicuously temperature-dependent and greatly enhanced thermal conductivity under high temperatures verify that Brownian motion should be one key effect factor in the heat transport processes of ionic liquid-based gold nanofluids. While the positive influences of proper aggregation and the optimized particle size on their thermal conductivity enhancements under some specific conditions demonstrate that clustering may be another critical effect factor in heat transport processes. Moreover, the remarkable difference of the thermal conductivity enhancements of the nanofluids containing Au NPs with different surface states could be attributed to the surface state which has a strong correlation with not only Brownian motion but also clustering. Whilst the close relationship between their thermal conductivity enhancements and the viscosity of base liquid further indicate Brownian motion must occupy the leading position among various influencing factors. Finally, a promisingly synergistic effect of Brownian motion and clustering based on experimental clues and theoretical analyses was first proposed, justifying different mechanisms are sure related. The results may shed lights on comprehensive understanding of heat transport mechanisms in nanofluids. PMID:21723564

  1. Can ionic liquids be used as templating agents for controlled design of uranium-containing nanomaterials?

    SciTech Connect

    Visser, Ann E., E-mail: ann.visser@srnl.doe.gov; Bridges, Nicholas J.; Tosten, Michael H.

    2013-09-01

    Graphical abstract: - Highlights: • Uranium oxides nanoparticles prepared using ionic liquids. • IL cation alkyl length impacts oxide morphology. • Low temperature UO{sub 2} synthesis. - Abstract: Nanostructured uranium oxides have been prepared in ionic liquids as templating agents. Using the ionic liquids as reaction media for inorganic nanomaterials takes advantage of the pre-organized structure of the ionic liquids which in turn controls the morphology of the inorganic nanomaterials. Variation of ionic liquid cation structure was investigated to determine the impact on the uranium oxide morphologies. For two ionic liquid cations, increasing the alkyl chain length increases the aspect ratio of the resulting nanostructured oxides. Understanding the resulting metal oxide morphologies could enhance fuel stability and design.

  2. Modulating the Solubilities of Ionic Liquid Components in Aqueous-Ionic Liquid Biphasic Systems: A Q-NMR Investigation.

    PubMed

    Atanassova, Maria; Mazan, Valérie; Billard, Isabelle

    2015-06-01

    Aqueous-ionic liquid (A-IL) biphasic systems have been examined in terms of deuterated water, acid, and IL cation and anion mutual solubilities in the upper (water-rich, in mole fraction) and lower phase of aqueous/IL biphasic systems at ambient temperature. The biphasic mixtures were composed of deuterated acids of various concentrations (mainly DCl, DNO3 , and DClO4 from 10(-2) to 10(-4) ?M) and five ionic liquids of the imidazolium family with a hydrophobic anion (CF3 SO2 )2 N(-) , that is, [C1 Cn im][Tf2 N], (n=2, 4, 6, 8 and 10). The analytical techniques applied were (1) H?NMR, (19) F?NMR, Karl-Fischer titration, pH potentiometry for IL cations and anions, and water and acid determination. The effects of the ionic strength (?=0.1?M NaCl and NaNO3 as well as ?=0.1?M, 0.2?M and 0.4?M NaClO4 , according to the investigated acid), the nature of the IL cation, and the nature of the mineral acid on the solubilities of the (D2 O, D(+) , Tf2 N(-) , C1 Cn im(+) ) entities in the lower or upper phases were determined. The addition of sodium perchlorate was found to enhance the Tf2 N(-) solubility while inhibiting the solubility of the ionic liquid cation. Differences in IL cation and anion solubilities of up to 42?mM were evidenced. The consequences for the characterization of the aqueous biphasic system, the solvent extraction process of the metal ions, and the ecological impact of the ILs are discussed. PMID:25787248

  3. Liquid-liquid equilibrium of cholinium-derived bistriflimide ionic liquids with water and octanol.

    PubMed

    Costa, Anabela J L; Soromenho, Mário R C; Shimizu, Karina; Marrucho, Isabel M; Esperança, José M S S; Canongia Lopes, J N; Rebelo, Luís Paulo N

    2012-08-01

    The liquid-liquid equilibria of mixtures of cholinum-based ionic liquids (N-alkyl-N,N-dimethylhydroxyethylammonium bis(trifluoromethane)sulfonylimide, [N(11n2OH)][Ntf(2)], n = 1, 2, 3, 4, and 5) plus water or 1-octanol were investigated at atmospheric pressure over the entire composition range. The experiments were conducted between 265 and 385 K using the cloud-point method. The systems exhibit phase diagrams consistent with the existence of upper critical solution temperatures. The solubility of [N(1 1 n 2OH)][Ntf(2)] in water is lower for cations with longer alkyl side chains (larger n values). The corresponding trend in the octanol mixtures is reversed. The ([N(1 1 1 2OH)][Ntf(2)] + water + octanol) ternary system shows triple liquid-liquid immiscibility at room temperature and atmospheric pressure. A combined analytic/synthetic method was used to estimate the corresponding phase diagram under those conditions. Auxiliary molecular dynamics simulation data were used to interpret the experimental results at a molecular level. PMID:22770438

  4. Chemistry of polynuclear transition-metal complexes in ionic liquids.

    PubMed

    Ahmed, Ejaz; Ruck, Michael

    2011-10-01

    Transition-metal chemistry in ionic liquids (IL) has achieved intrinsic fascination in the last few years. The use of an IL as environmental friendly solvent, offers many advantages over traditional materials synthesis methods. The change from molecular to ionic reaction media leads to new types of materials being accessible. Room-temperature IL have been found to be excellent media for stabilising transition-metal clusters in solution and to crystallise homo- and heteronuclear transition-metal complexes and clusters. Furthermore, the use of IL as solvent provides the option to replace high-temperature routes, such as crystallisation from the melt or gas-phase deposition, by convenient room- or low-temperature syntheses. Inorganic IL composed of alkali metal cations and polynuclear transition-metal cluster anions are also known. Each of these areas will be discussed briefly in this contribution. PMID:21743925

  5. Graphene/Ionic Liquid Composite Films and Ion Exchange

    NASA Astrophysics Data System (ADS)

    Mo, Yufei; Wan, Yunfang; Chau, Alicia; Huang, Fuchuan

    2014-06-01

    Wettability of graphene is adjusted by the formation of various ionic surfaces combining ionic liquid (IL) self-assembly with ion exchange. The functionalized ILs were designed and synthesized with the goal of obtaining adjustable wettability. The wettability of the graphene surface bearing various anions was measured systematically. The effect of solvent systems on ion exchange ratios on the graphene surface has also been investigated. Meanwhile, the mechanical properties of the graphene/IL composite films were investigated on a nanometer scale. The elasticity and adhesion behavior of the thin film was determined with respected to the indentation deformation by colloid probe nanoindentation method. The results indicate that anions played an important role in determining graphene/IL composite film properties. In addition, surface wetting and mechanics can be quantitatively determined according to the counter-anions on the surface. This study might suggest an alternate way for quantity detection of surface ions by surface force.

  6. Graphene/Ionic Liquid Composite Films and Ion Exchange

    PubMed Central

    Mo, Yufei; Wan, Yunfang; Chau, Alicia; Huang, Fuchuan

    2014-01-01

    Wettability of graphene is adjusted by the formation of various ionic surfaces combining ionic liquid (IL) self-assembly with ion exchange. The functionalized ILs were designed and synthesized with the goal of obtaining adjustable wettability. The wettability of the graphene surface bearing various anions was measured systematically. The effect of solvent systems on ion exchange ratios on the graphene surface has also been investigated. Meanwhile, the mechanical properties of the graphene/IL composite films were investigated on a nanometer scale. The elasticity and adhesion behavior of the thin film was determined with respected to the indentation deformation by colloid probe nanoindentation method. The results indicate that anions played an important role in determining graphene/IL composite film properties. In addition, surface wetting and mechanics can be quantitatively determined according to the counter-anions on the surface. This study might suggest an alternate way for quantity detection of surface ions by surface force. PMID:24970602

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

    PubMed

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

    2013-01-31

    Amino acid ionic liquids are a special class of ionic liquids due to their unique acid-base behavior, biological significance, and applications in different fields such as templates in synthetic chemistry, stabilizers for biological macromolecules, etc. The physicochemical properties of these ionic liquids can easily be altered by making the different combinations of amino acids as anion along with possible cation modification which makes amino acid ionic liquids more suitable to understand the different kinds of molecular and ionic interactions with sufficient depth so that they can provide fruitful information for a molecular level understanding of more complicated biological processes. In this context, volumetric and osmotic coefficient measurements for aqueous solutions containing 1-ethyl-3-methylimidazolium ([Emim]) based amino acid ionic liquids of glycine, alanine, valine, leucine, and isoleucine are reported at 298.15 K. From experimental osmotic coefficient data, mean molal activity coefficients of ionic liquids were estimated and analyzed using the Debye-Hückel and Pitzer models. The hydration numbers of ionic liquids in aqueous solutions were obtained using activity data. Pitzer ion interaction parameters are estimated and compared with other electrolytes reported in the literature. The nonelectrolyte contribution to the aqueous solutions containing ionic liquids was studied by calculating the osmotic second virial coefficient through an application of the McMillan-Mayer theory of solution. It has been found that the second osmotic virial coefficient which includes volume effects correlates linearly with the Pitzer ion interaction parameter estimated independently from osmotic data as well as the hydrophobicity of ionic liquids. The enthalpy-entropy compensation effect, explained using the Starikov-Nordén model of enthalpy-entropy compensation, and partial molar entropy analysis for aqueous [Emim][Gly] solutions are made by using experimental Gibb's free energy data and literature enthalpy data. This study highlights that the hydrophobic interaction persists even in the limit of infinite dilution where the hydration effects are usually dominant, implying importance of hydrophobic hydration. Analysis of the results further shows that the hydration of amino acid ionic liquids occurs through the cooperative H-bond formation with the kosmotropic effect in contrast to the usual inorganic salts or hydrophobic salts like tetraalkylammonium halides. PMID:23293839

  8. Synthesis and Characterization of Thiazolium-Based Room Temperature Ionic Liquids for Gas Separations

    SciTech Connect

    Hillesheim, Patrick C [ORNL; Mahurin, Shannon Mark [ORNL; Fulvio, Pasquale F [ORNL; Yeary, Joshua S [ORNL; Oyola, Yatsandra [ORNL; Jiang, Deen [ORNL; Dai, Sheng [ORNL

    2012-01-01

    A series of novel thiazolium-bis(triflamide) based ionic liquids has been synthesized and characterized. Physicochemical properties of the ionic liquids such as thermal stability, phase transitions, and infrared spectra were analysed and compared to the imidazolium-based congeners. Several unique classes of ancillary substitutions are examined with respect to impacts on overall structure, in addition to their carbon dioxide absorption properties in supported ionic-liquid membranes for gas separation.

  9. Hydrolysis of cellulose in SO 3H-functionalized ionic liquids

    Microsoft Academic Search

    Furong Tao; Huanling Song; Lingjun Chou

    2011-01-01

    Influence of acidity and structure of ionic liquids on microcrystalline cellulose (MCC) hydrolysis was investigated. MnCl2-containing ionic liquids (ILs) were efficient catalysts and achieved MCC conversion rates of 91.2% and selectivities for 5-hydroxymethyl furfural (HMF), furfural and levulinic acid (LA) of 45.7%, 26.2% and 10.5%, respectively. X-ray diffractometry indicated that catalytic hydrolysis of MCC in ionic liquids resulted in the

  10. Density and refractive index measurements of 1-ethyl-3-methylimidazolium-based ionic liquids

    Microsoft Academic Search

    Allan N. Soriano; Bonifacio T. Doma Jr.; Meng-Hui Li

    2010-01-01

    This work was the continuation of our previous study where the correlations between density and refractive index of pure systems of ionic liquids were examined. The density and refractive index of five 1-ethyl-3-methylimidazolium-based ionic liquids were measured at standard pressure and temperature up to 353.2K. Densities and refractive indices of the studied ionic liquids were presented as a function of

  11. Preparation of functional ionic liquids and tribological investigation of their ultra-thin films

    Microsoft Academic Search

    Guiqin Yu; Feng Zhou; Weimin Liu; Yongmin Liang; Shiqiang Yan

    2006-01-01

    Novel ionic liquid materials based on 1-alkyl-4-[5-(alkylsulfanyl)-1,3,4-oxadiazol-2-yl] pyridinium tetrafluoroborate derivatives were synthesized. Ultra-thin ionic liquid films were prepared on silicon wafers by means of spin-coating and their tribological properties were investigated. The wear life increases when the chain length decreases. Under low load, they show good tribological properties which are closely related to the interaction between ionic liquid and substrate

  12. Effect and mechanism of additives for ionic liquids as new lubricants

    Microsoft Academic Search

    Hideto Kamimura; Tomoo Kubo; Ichiro Minami; Shigeyuki Mori

    2007-01-01

    Ionic liquids are unique compounds, which exhibit low viscosity, non-flammability, low vapor pressure, and extremely high thermal stability. Therefore, they are expected as candidates for advanced lubricants. Several ionic liquids, derived from cations such as imidazolium, pridinium, ammonium, and anions such as BF4-, bis(trifluoromethylsulfonyl)imide (TFSI-) were examined under boundary conditions. It was found that tribological properties of ionic liquids are

  13. Ionic liquid promoted selective oxidation of organic compounds with NaBrO 3

    Microsoft Academic Search

    Ahmad Shaabani; Elham Farhangi; Abbas Rahmati

    2008-01-01

    1-Butyl-3-methylimidazolium bromide ([bmim]Br) as an ionic liquid promoted selectively the oxidation of alkyl arenes and alcohols to the corresponding carbonyl compounds\\u000a with NaBrO3 in excellent yields under neutral conditions at the 70°C. Among the various ionic liquids examined, the [bmim]Br exhibited the best performances with NaBrO3. The ionic liquid can be recycled and reused for several runs without any significant

  14. Low-melting mixtures based on choline ionic liquids.

    PubMed

    Rengstl, Doris; Fischer, Veronika; Kunz, Werner

    2014-11-01

    In this article a strategy is proposed for the design of low toxic, room temperature liquid low-melting mixtures (LMMs) which are entirely composed of natural materials. From literature it is well known that, in general, deep eutectic solvents based on choline chloride and dicarboxylic acids are LMMs, but not liquids at room temperature, with one exception: a 1?:?1 molar mixture of malonic acid and choline chloride. Therefore, the starting point of this study was the decrease of the melting point of one of the components, namely the dicarboxylic acid, which is succinic, glutaric or adipic acid. For this purpose, one of the two protons of the acidic group was exchanged by a bulky unsymmetrical choline cation. The resulting ionic liquids (ILs) were still solid at room temperature, but have a reduced melting temperature compared to the corresponding acids. In the second step, mixtures of these ILs with choline chloride were prepared. It turned out that choline glutarate-choline chloride mixtures are liquids at room temperature at compositions containing 95-98 wt% of choline glutarate. Finally, urea was added as another hydrogen bond donor. Density, conductivity and viscosity measurements were performed for all obtained mixtures. Moreover, a Walden plot was drawn which indicates that all mixtures are liquids with fully dissociated ions moving independently. Therefore, they are considered as "good" ionic liquids and, thus, for example they can be used to exchange more toxic or less biodegradable ILs in application processes. A brief outlook containing application possibilities is given. It is demonstrated that choline dodecylsulfate is readily soluble in these mixtures, forming aggregates in the LMM at temperatures exceeding 55 °C. PMID:25242504

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

    PubMed

    Rout, Alok; Binnemans, Koen

    2015-01-21

    Trivalent rare-earth ions were extracted from nitric acid medium by the neutral phosphine oxide extractant Cyanex 923 into ionic liquid phases containing the bis(trifluoromethylsulfonyl)imide anion. Five different cations were considered: 1-butyl-3-methylimidazolium, 1-decyl-3-methylimidazolium, methyltributylammonium, methyltrioctylammonium and trihexyl(tetradecyl)phosphonium. The extraction behavior of neodymium(iii) was investigated as a function of various parameters: pH, extractant concentration, concentration of the neodymium(iii) ion in the aqueous feed and concentration of the salting-out agent. The loading capacity of the ionic liquid phase was studied. The extraction efficiency increased with increasing pH of the aqueous feed solution. The extraction occurred for all ionic liquids via an ion-exchange mechanism and the extraction efficiency could be related to the solubility of the ionic liquid cation in the aqueous phase: high distribution ratios for hydrophilic cations and low ones for hydrophobic cations. Addition of nitrate ions to the aqueous phase resulted in an increase in extraction efficiency for ionic liquids with hydrophobic cations due to extraction of neutral complexes. Neodymium(iii) could be stripped from the ionic liquid phase by 0.5-1.0 M nitric acid solutions and the extracting phase could be reused. The extractability of other rare earths present in the mixture was compared for the five ionic liquids. PMID:25423581

  16. Crown-Type Ionic Liquids as Lubricants for Steel-on-Steel System

    Microsoft Academic Search

    Dong Jiang; Litian Hu; Dapeng Feng

    2011-01-01

    A series of novel imidazolium-based crown-type phosphate ionic liquid lubricants have been designed and synthesized. Because\\u000a the anions of ionic liquids are organic phosphate, crown-type ionic liquids would not corrode steel. The crown-type ionic\\u000a liquids exhibit better tribological properties than conventional lubricants, which were evaluated by a ball-on-flat type Optimol-SRV\\u000a oscillating friction and wear tester. The chemical compositions of the

  17. High CO2 Solubility, Permeability and Selectivity in Ionic Liquids with the Tetracyanoborate Anion

    SciTech Connect

    Mahurin, Shannon Mark [ORNL; Hillesheim, Patrick C [ORNL; Yeary, Joshua S [ORNL; Jiang, Deen [ORNL; Dai, Sheng [ORNL

    2012-01-01

    Five different ionic liquids containing the tetracyanoborate anion were synthesized and evaluated for CO2 separation performance. Measured CO2 solubility values were exceptionally high compared to analogous ionic liquids with different anions and ranged from 0.128 mol L-1 atm-1 to 0.148 mol L-1 atm-1. In addition, CO2 permeability and CO2/N2 selectivity values were measured using a supported ionic liquid membrane architecture and the separations performance of the ionic liquid membranes exceeded the Robeson upper bound. These results establish the distinct potential of the tetracyanoborate, [B(CN)4], anion for the separation of CO2.

  18. The Effect of Ionic Liquids on Protein Crystallization and X-ray Diffraction Resolution

    SciTech Connect

    Judge, Russell A.; Takahashi, Sumiko; Longenecker, Kenton L.; Fry, Elizabeth H.; Abad-Zapatero, Cele; Chiu, Mark L.; (Abbott)

    2009-09-08

    Ionic liquids exhibit a variety of properties that make them attractive solvents for biomaterials. Given the potential for productive interaction between ionic liquids and biological macromolecules, we investigated the use of ionic liquids as precipitating agents and additives for protein crystallization for six model proteins (lysozyme, catalase, myoglobin, trypsin, glucose isomerase, and xylanase). The ionic liquids produced changes in crystal morphology and mediated significant increases in crystal size in some cases. Crystals grown using ionic liquids as precipitating agents or as additives provided X-ray diffraction resolution similar to or better than that obtained without ionic liquids. Based upon the experiments performed with model proteins, the ionic liquids were used as additives for the crystallization of the poorly diffracting monoclonal antibody 106.3 Fab in complex with the B-type natriuretic peptide (5-13). The ionic liquids improved the crystallization behavior and provided improved diffraction resulting in the determination of the structure. Ionic liquids should be considered as useful additives for the crystallization of other proteins.

  19. Methods of using ionic liquids having a fluoride anion as solvents

    DOEpatents

    Pagoria, Philip (Livermore, CA); Maiti, Amitesh (San Ramon, CA); Gash, Alexander (Brentwood, CA); Han, Thomas Yong (Pleasanton, CA); Orme, Christine (Oakland, CA); Fried, Laurence (Livermore, CA)

    2011-12-06

    A method in one embodiment includes contacting a strongly hydrogen bonded organic material with an ionic liquid having a fluoride anion for solubilizing the strongly hydrogen bonded organic material; and maintaining the ionic liquid at a temperature of about 90.degree. C. or less during the contacting. A method in another embodiment includes contacting a strongly hydrogen bonded organic material with an ionic liquid having an acetate or formate anion for solubilizing the strongly hydrogen bonded organic material; and maintaining the ionic liquid at a temperature of less than about 90.degree. C. during the contacting.

  20. Mechanical Properties of Composite SPEEK Polymer Membranes Modified with Ionic Liquids

    NASA Astrophysics Data System (ADS)

    Sprugis, E.; Reinholds, I.; Vaivars, G.

    2015-03-01

    In this work, the mechanical properties of sulphonated polyetheretherketone (SPEEK) membranes impregnated with 3 different ionic liquids (1-butyl-2,3-dimethyl- imidazolium dimethylphosphate ([BMMIM][Me2PO4])), 1,2,3-trimethylimidazolium dimethylphosphate ([MMMIM][Me2PO4])), 1,3-dimethylimidazolium dimethylphosphate ([MMIM][Me2PO4])) have been investigated. Prepared SPEEK/ionic liquid composite membranes are characterized by mechanical testing both in room and elevated temperatures. It was found that the stiffness and tensile strength of composites decreased by increasing the content of ionic liquid and the length of alkyl radical in ionic liquid as well as by increasing the temperature.

  1. Electrochemical transistors with ionic liquids for enzymatic sensing

    NASA Astrophysics Data System (ADS)

    Fraser, Kevin J.; Yang, Sang Yoon; Cicoira, Fabio; Curto, Vincenzo F.; Byrne, Robert; Benito-Lopez, Fernando; Khodagholy, Dion; Owens, Róisín M.; Malliaras, George G.; Diamond, Dermot

    2011-10-01

    Over the past decade conducting polymer electrodes have played an important role in bio-sensing and actuation. Recent developments in the field of organic electronics have made available a variety of devices that bring unique capabilities at the interface with biology. One example is organic electrochemical transistors (OECTs) that are being developed for a variety of bio-sensing applications, including the detection of ions, and metabolites, such as glucose and lactate. Room temperature ionic liquids (RTILs) are organic salts, which are liquid at ambient temperature. Their nonvolatile character and thermal stability makes them an attractive alternative to conventional organic solvents. Here we report an enzymatic sensor based on an organic electro-chemical transistor with RTIL's as an integral part of its structure and as an immobilization medium for the enzyme and the mediator. Further investigation shows that these platforms can be incorporated into flexible materials such as carbon cloth and can be utilized for bio-sensing. The aim is to incorporate the overall platform in a wearable sensor to improve athlete performance with regards to training. In this manuscript an introduction to ionic liquids (ILs), IL - enzyme mixtures and a combination of these novel materials being used on OECTs are presented.

  2. Li(+) solvation in glyme-Li salt solvate ionic liquids.

    PubMed

    Ueno, Kazuhide; Tatara, Ryoichi; Tsuzuki, Seiji; Saito, Soshi; Doi, Hiroyuki; Yoshida, Kazuki; Mandai, Toshihiko; Matsugami, Masaru; Umebayashi, Yasuhiro; Dokko, Kaoru; Watanabe, Masayoshi

    2015-03-28

    Certain molten complexes of Li salts and solvents can be regarded as ionic liquids. In this study, the local structure of Li(+) ions in equimolar mixtures ([Li(glyme)]X) of glymes (G3: triglyme and G4: tetraglyme) and Li salts (LiX: lithium bis(trifluoromethanesulfonyl)amide (Li[TFSA]), lithium bis(pentafluoroethanesulfonyl)amide (Li[BETI]), lithium trifluoromethanesulfonate (Li[OTf]), LiBF4, LiClO4, LiNO3, and lithium trifluoroacetate (Li[TFA])) was investigated to discriminate between solvate ionic liquids and concentrated solutions. Raman spectra and ab initio molecular orbital calculations have shown that the glyme molecules adopt a crown-ether like conformation to form a monomeric [Li(glyme)](+) in the molten state. Further, Raman spectroscopic analysis allowed us to estimate the fraction of the free glyme in [Li(glyme)]X. The amount of free glyme was estimated to be a few percent in [Li(glyme)]X with perfluorosulfonylamide type anions, and thereby could be regarded as solvate ionic liquids. Other equimolar mixtures of [Li(glyme)]X were found to contain a considerable amount of free glyme, and they were categorized as traditional concentrated solutions. The activity of Li(+) in the glyme-Li salt mixtures was also evaluated by measuring the electrode potential of Li/Li(+) as a function of concentration, by using concentration cells against a reference electrode. At a higher concentration of Li salt, the amount of free glyme diminishes and affects the electrode reaction, leading to a drastic increase in the electrode potential. Unlike conventional electrolytes (dilute and concentrated solutions), the significantly high electrode potential found in the solvate ILs indicates that the solvation of Li(+) by the glyme forms stable and discrete solvate ions ([Li(glyme)](+)) in the molten state. This anomalous Li(+) solvation may have a great impact on the electrode reactions in Li batteries. PMID:25733406

  3. Fast Measurement of Methanol Concentration in Ionic Liquids by Potential Step Method

    PubMed Central

    Hainstock, Michael L.; Tang, Yijun

    2015-01-01

    The development of direct methanol fuel cells required the attention to the electrolyte. A good electrolyte should not only be ionic conductive but also be crossover resistant. Ionic liquids could be a promising electrolyte for fuel cells. Monitoring methanol was critical in several locations in a direct methanol fuel cell. Conductivity could be used to monitor the methanol content in ionic liquids. The conductivity of 1-butyl-3-methylimidazolium tetrafluoroborate had a linear relationship with the methanol concentration. However, the conductivity was significantly affected by the moisture or water content in the ionic liquid. On the contrary, potential step could be used in sensing methanol in ionic liquids. This method was not affected by the water content. The sampling current at a properly selected sampling time was proportional to the concentration of methanol in 1-butyl-3-methylimidazolium tetrafluoroborate. The linearity still stood even when there was 2.4?M water present in the ionic liquid. PMID:25802522

  4. Complex formation of ionic liquid surfactant and ?-cyclodextrin

    Microsoft Academic Search

    Na Li; Jie Liu; Xueyan Zhao; Yan’an Gao; Liqiang Zheng; Jin Zhang; Li Yu

    2007-01-01

    An ionic liquid (IL) surfactant, 1-dodecyl-3-methylimidazolium hexafluorophosphate (C12mimPF6) can form the inclusion complexes (ICs) with ?-cyclodextrin (?-CD). The surface tension measurements revealed that there were two kinds of inclusion formations, 1:1 and 1:2 (?-CD\\/IL) stoichiometry for ?-CD-C12mimPF6 ICs. The inclusion complexation interaction was further confirmed by FT-IR spectra. The inclusion compound was also characterized by Powder X-ray diffraction (XRD), 13C

  5. Highly doped alkaline earth nanofluorides synthesized from ionic liquids

    NASA Astrophysics Data System (ADS)

    Lorbeer, C.; Cybinska, J.; Zych, E.; Mudring, A.-V.

    2011-12-01

    Bulk alkaline earth fluorides co-doped with optically active ions are prominent materials for luminescent applications. However, for phosphor materials the changeover to the nanoscale is a tightrope walk between achieving desirable features of small particles such as reduced light scattering and unwanted drawbacks such as a high surface defect concentration which is likely to result in quenching of luminescence. A new preparation route via ionic liquids allows obtaining pure and oxygen-free alkaline earth fluorides co-doped with Eu 3+ and Gd 3+ on the nanoscale with excellent quantum cutting abilities.

  6. An ionic liquid process for mercury removal from natural gas.

    PubMed

    Abai, Mahpuzah; Atkins, Martin P; Hassan, Amiruddin; Holbrey, John D; Kuah, Yongcheun; Nockemann, Peter; Oliferenko, Alexander A; Plechkova, Natalia V; Rafeen, Syamzari; Rahman, Adam A; Ramli, Rafin; Shariff, Shahidah M; Seddon, Kenneth R; Srinivasan, Geetha; Zou, Yiran

    2015-05-14

    Efficient scrubbing of mercury vapour from natural gas streams has been demonstrated both in the laboratory and on an industrial scale, using chlorocuprate(II) ionic liquids impregnated on high surface area porous solid supports, resulting in the effective removal of mercury vapour from natural gas streams. This material has been commercialised for use within the petroleum gas production industry, and has currently been running continuously for three years on a natural gas plant in Malaysia. Here we report on the chemistry underlying this process, and demonstrate the transfer of this technology from gram to ton scale. PMID:25722100

  7. Ionic Liquids as Lubricants of Titanium–Steel Contact

    Microsoft Academic Search

    Ana Eva Jiménez; María-Dolores Bermúdez

    2009-01-01

    The friction and wear behavior of grade 3 titanium have been studied against AISI 52100 steel at room temperature and at 100 °C,\\u000a in the presence of six ionic liquid (IL) lubricants, four imidazolium ILs, 1-ethyl-3-methylimidazolium tetrafluoroborate (L102),\\u000a 1-octyl,-3-methylimidazolium tetrafluoroborate (L108), 1-hexyl, 3-methylimidazolium hexafluorophosphate (L-P106) and 1-benzyl,3-methylimidazolium\\u000a chloride (ClB), and two quaternary ammonium salts, the chloride derivative AMMOENG™ 101 (AM-101) and

  8. Diffuse-charge dynamics of ionic liquids in electrochemical systems

    NASA Astrophysics Data System (ADS)

    Zhao, Hui

    2011-11-01

    We employ a continuum theory of solvent-free ionic liquids accounting for both short-range electrostatic correlations and steric effects (finite ion size) [Bazant , Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.106.046102 106, 046102 (2011)] to study the response of a model microelectrochemical cell to a step voltage. The model problem consists of a 1-1 symmetric ionic liquid between two parallel blocking electrodes, neglecting any transverse transport phenomena. Matched asymptotic expansions in the limit of thin double layers are applied to analyze the resulting one-dimensional equations and study the overall charge-time relation in the weakly nonlinear regime. One important conclusion is that our simple scaling analysis suggests that the length scale ?D*lc* accurately characterizes the double-layer structure of ionic liquids with strong electrostatic correlations where lc* is the electrostatic correlation length (in contrast, the Debye screening length ?D* is the primary double-layer length for electrolytes) and the response time of ?D*3/2L*/(D*lc1/2) (not ?D*L*/D* that is the primary charging time of electrolytes) is the correct charging time scale of ionic liquids with strong electrostatic correlations where D* is the diffusivity and L* is the separation length of the cell. With these two new scales, data of both electric potential versus distance from the electrode and the total diffuse charge versus time collapse onto each individual master curve in the presence of strong electrostatic correlations. In addition, the dependance of the total diffuse charge on steric effects, short-range correlations, and driving voltages is thoroughly examined. The results from the asymptotic analysis are compared favorably with those from full numerical simulations. Finally, the absorption of excess salt by the double layer creates a depletion region outside the double layer. Such salt depletion may bring a correction to the leading order terms and break down the weakly nonlinear analysis. A criterion which justifies the weakly nonlinear analysis is verified with numerical simulations.

  9. Regenerating cellulose from ionic liquids for an accelerated enzymatic hydrolysis

    SciTech Connect

    Zhao, Hua [Savannah State University; Jones, Cecil L [Savannah State University; Baker, Gary A [ORNL; Xia, Shuqian [Tianjin University, Tianjin, China; Olubajo, Olarongbe [Savannah State University; Person, Vernecia [Savannah State University

    2009-01-01

    The efficient conversion of lignocellulosic materials into fuel ethanol has become a research priority in producing affordable and renewable energy. The pretreatment of lignocelluloses is known to be key to the fast enzymatic hydrolysis of cellulose. Recently, certain ionic liquids (ILs)were found capable of dissolving more than 10 wt% cellulose. Preliminary investigations [Dadi, A.P., Varanasi, S., Schall, C.A., 2006. Enhancement of cellulose saccharification kinetics using an ionic liquid pretreatment step. Biotechnol. Bioeng. 95, 904 910; Liu, L., Chen, H., 2006. Enzymatic hydrolysis of cellulose materials treated with ionic liquid [BMIM]Cl. Chin. Sci. Bull. 51, 2432 2436; Dadi, A.P., Schall, C.A., Varanasi, S., 2007. Mitigation of cellulose recalcitrance to enzymatic hydrolysis by ionic liquid pretreatment. Appl. Biochem. Biotechnol. 137 140, 407 421] suggest that celluloses regenerated from IL solutions are subject to faster saccharification than untreated substrates. These encouraging results offer the possibility of using ILs as alternative and nonvolatile solvents for cellulose pretreatment. However, these studies are limited to two chloride-based ILs: (a) 1-butyl-3-methylimidazolium chloride ([BMIM]Cl), which is a corrosive, toxic and extremely hygroscopic solid (m.p. 70 C), and (b) 1-allyl-3-methylimidazolium chloride ([AMIM]Cl), which is viscous and has a reactive side-chain. Therefore, more in-depth research involving other ILs is much needed to explore this promising pretreatment route. For this reason, we studied a number of chloride- and acetate-based ILs for cellulose regeneration, including several ILs newly developed in our laboratory. This will enable us to select inexpensive, efficient and environmentally benign solvents for processing cellulosic biomass. Our data confirm that all regenerated celluloses are less crystalline (58 75% lower) and more accessible to cellulase (>2 times) than untreated substrates. As a result, regenerated Avicel cellulose, filter paper and cottonwere hydrolyzed 2 10 times faster than the respective untreated celluloses. A complete hydrolysis of Avicel cellulose could be achieved in 6 h given the Trichoderma reesei cellulase/substrate ratio (w/w) of 3:20 at 50 C. In addition,we observed that cellulase is more thermally stable (up to 60 C) in the presence of regenerated cellulose. Furthermore, our systematic studies suggest that the presence of various ILs during the hydrolysis induced different degrees of cellulase inactivation. Therefore, a thorough removal of IL residues after cellulose regeneration is highly recommended, and a systematic investigation on this subject is much needed.

  10. Synthesis and properties of trigeminal tricationic ionic liquids.

    PubMed

    Pernak, Juliusz; Skrzypczak, Andrzej; Lota, Grzegorz; Frackowiak, Elzbieta

    2007-01-01

    Novel trigeminal tricationic ionic liquids (TTILs) have been successfully synthesized in high yields by means of Menschutkin quaternization via an S(N)1 mechanism. This reaction presents a new convenient method for transforming glycerol into multifunctional compounds. The physical properties of a series of TTILs were characterized by using a variety of techniques. The prepared salts were tested for antimicrobial activity. Electrochemical characterization of TTILs was also performed, which allowed the estimation of the conductivity of these new compounds, to establish their electrochemical stability window and capacitance properties over a wide range of temperatures. A good correlation of the physical properties of TTILs with capacitance values was observed. PMID:17212367

  11. Synthesis of cellulose methylcarbonate in ionic liquids using dimethylcarbonate.

    PubMed

    Labafzadeh, Sara R; Helminen, K Juhani; Kilpeläinen, Ilkka; King, Alistair W T

    2015-01-01

    Dialkylcarbonates are viewed as low-cost, low-toxicity reagents, finding application in many areas of green chemistry. Homogeneous alkoxycarbonylation of cellulose was accomplished by applying dialkycarbonates (dimethyl and diethyl carbonate) in the ionic liquid-electrolyte trioctylphosphonium acetate ([P8881 ][OAc])/DMSO or 1-ethyl-3-methylimidazolium acetate ([emim][OAc]). Cellulose dialkylcarbonates with a moderate degree of substitution (DS?1) are accessible via this procedure and cellulose methylcarbonate was thoroughly characterized for its chemical and physical properties after regeneration. This included HSQC & HMBC?NMR, ATR-IR, molecular weight distribution, morphology, thermal properties, and barrier properties after film formation. PMID:25378289

  12. Hydrogen Fluoride Capture by Imidazolium Acetate Ionic Liquid

    E-print Network

    Chaban, Vitaly

    2015-01-01

    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, I will evaluate performance of imidazolium acetate and outline systematic search guidelines for efficient adsorption and extraction of HF.

  13. 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. PMID:22910970

  14. Synthesis and characterization of ionic polymer networks in a room-temperature ionic liquid.

    PubMed

    Stanzione, Joseph F; Jensen, Robert E; Costanzo, Philip J; Palmese, Giuseppe R

    2012-11-01

    Ionic liquid gels (ILGs) for potential use in ion transport and separation applications were generated via a free radical copolymerization of 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and N,N'-methylene(bis)acrylamide (MBA) using 1-ethyl-3-methylimidazolium ethylsulfate (IL) as a room temperature ionic liquid solvent medium. The AMPS and MBA monomer solubility window in the IL in the temperature range of 25 to 65 °C was determined. In situ ATR-FTIR showed near complete conversion of monomers to a cross-linked polymer network. ILGs with glass transition temperatures (T(g)s) near -50 °C were generated with T(g) decreasing with increasing IL content. The elastic moduli in compression (200 to 6600 kPa) decreased with increasing IL content and increasing AMPS content while the conductivities (0.35 to 2.14 mS cm?¹) increased with increasing IL content and decreasing MBA content. The polymer-IL interaction parameter (?) (0.48 to 0.55) was determined via a modified version of the Bray and Merrill equation. PMID:23088450

  15. Improving hydrothermal carbonization by using poly(ionic liquid)s.

    PubMed

    Zhang, Pengfei; Yuan, Jiayin; Fellinger, Tim-Patrick; Antonietti, Markus; Li, Haoran; Wang, Yong

    2013-06-01

    Pores for thought: Porous nitrogen-doped carbon materials (HTC Carbon with PILs) composed of spherical nanoparticles, and also those with Au-Pd core-shell nanoparticles embedded (Au-Pd@N-Carbon) were synthesized. These materials can be prepared from sugars by hydrothermal carbonization (160-200 °C) in the presence of poly(ionic liquid)s (PILs), which act as a stabilizer, pore-generating agent, and nitrogen source. PMID:23592443

  16. Chiral ionic liquids in chromatographic and electrophoretic separations.

    PubMed

    Kapnissi-Christodoulou, Constantina P; Stavrou, Ioannis J; Mavroudi, Maria C

    2014-10-10

    This report provides an overview of the application of chiral ionic liquids (CILs) in separation technology, and particularly in capillary electrophoresis and both gas and liquid chromatography. There is a large number of CILs that have been synthesized and designed as chiral agents. However, only a few have successfully been applied in separation technology. Even though this application of CILs is still in its early stages, the scientific interest is increasing dramatically. This article is focused on the use of CILs as chiral selectors, background electrolyte additives, chiral ligands and chiral stationary phases in electrophoretic and chromatographic techniques. Different examples of CILs, which contain either a chiral cation, a chiral anion or both, are presented in this review article, and their major advantages along with their potential applications in chiral electrophoretic and chromatographic recognition are discussed. PMID:24913367

  17. Exploring field effects on ionic liquid boundary lubrication

    NASA Astrophysics Data System (ADS)

    Capozza, Rosario; Benassi, Andrea; Vanossi, Andrea; Tosatti, Erio

    2014-03-01

    Ionic liquids, organic salts that are liquid at room temperature, are of great physical as well as of technological interest. Their adhesion properties to solid surfaces under pressure suggests their use as boundary lubricants. One potentially interesting feature would be the possibility that electrical charging of the solid plates or more generally an applied static or dynamic electric field could modify the nearby perpendicular and parallel ordering of ions, and in turn also modify the sliding friction. While these effects have just begun to be pursued by experimental groups, we have undertaken molecular dynamics simulations aimed at exploring some of these questions. Preliminary results obtained using very simple molten salt boundary lubrication models will be presented and discussed. Partly sponsored by SNSF Project CRSII2 136287/1, and by ERC Grant N. 320796 MODPHYSFRICT.

  18. Selective extraction of copper, mercury, silver and palladium ionsfrom water using hydrophobic ionic liquids.

    SciTech Connect

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

    2007-06-25

    Extraction of dilute metal ions from water was performed near room temperature with a variety of ionic liquids. Distribution coefficients are reported for fourteen metal ions extracted with ionic liquids containing cations 1-octyl-4-methylpyridinium [4MOPYR]{sup +}, 1-methyl-1-octylpyrrolidinium [MOPYRRO]{sup +} or 1-methyl-1-octylpiperidinium [MOPIP]{sup +}, and anions tetrafluoroborate [BF{sub 4}]{sup +}, trifluoromethyl sulfonate [TfO]{sup +} or nonafluorobutyl sulfonate [NfO]{sup +}. Ionic liquids containing octylpyridinium cations are very good for extracting mercury ions. However, other metal ions were not significantly extracted by any of these ionic liquids. Extractions were also performed with four new task-specific ionic liquids. Such liquids containing a disulfide functional group are efficient and selective for mercury and copper, whereas those containing a nitrile functional group are efficient and selective for silver and palladium.

  19. Photochromic imidazolium based ionic liquids based on spiropyran.

    PubMed

    Coleman, Simon; Byrne, Robert; Alhashimy, Nameer; Fraser, Kevin J; Macfarlane, Douglas R; Diamond, Dermot

    2010-07-14

    We investigate the physicochemical properties of a novel imidazolium benzospiropyran derivative, SP(Im), in imidazolium based ionic liquids (ILs). SP(Im) was prepared through alkylation of an imidazole to the photoswitchable compound and this derivative was characterised in imidazolium based ILs with increasing chain length to examine the stability of its merocyanine (MC) and spiropyran (SP) forms and compared to standard spiropyran, BSP. The rate of thermal relaxation of the new derivative is found to be about ten times faster than that of BSP as reflected in rates of 13.9 x 10(-3) s(-1) and 1.0 x 10(-3) s(-1) for SP(Im) and BSP, respectively, in [C(6)mIm][NTf(2)]. Since ILs are believed to form nano-structured domains it is proposed that the covalent attachment of the imidazolium side group of SP(Im) fully integrates the photoswitchable moiety into the non-polar region through side-chain association. In contrast, unbound BSP is relatively free to migrate between both polar and non-polar regions and the MC form is more readily stabilised by the IL charge via through space interactions and spontaneous movement to charged nano-domains leading to enhancement of the MC lifetime. At higher concentrations, rheological and transport properties were investigated to determine the impact of covalent attachment of the BSP fragment to an imidazolium cation on the ionic liquid structure. Ionic conductivity was found to decrease by up to 23% for SP(Im) with effects increasing with cation side-chain length. Unlike BSP, the photoswitching of the SP(Im) did not affect conductivity or viscosity values. This may indicate that the mobility of the photoswitchable compound and the resulting disruption of such movement may be critical to the control of this physical property. PMID:20467657

  20. Interactions of Ionic Liquids with Uranium and its Bioreduction

    SciTech Connect

    Zhang, C.; Francis, A.

    2012-09-18

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

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

    PubMed

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

    2015-10-01

    Complete biodegradation of a newly-synthesized chemical in a wastewater treatment plant (WWTP) eliminates the potential for novel environmental pollutants. However, differences within- and between-WWTP microbial communities may alter expectations for biodegradation. WWTP communities can also serve as a source of unique consortia that, when enriched, can metabolize chemicals that tend to resist degradation, but are otherwise promising green alternatives. We tested the biodegradability of three ionic liquids (ILs): 1-octyl-3-methylpyridinium bromide (OMP), 1-butyl-3-methylpyridinium bromide (BMP) and 1-butyl-3-methylimidazolium chloride (BMIM). We performed tests using communities from two WWTPs at three time points. Site-specific and temporal variation both influenced community composition, which impacted the success of OMP biodegradability. Neither BMP nor BMIM degraded in any test, suggesting that these ILs are unlikely to be removed by traditional treatment. Following standard biodegradation assays, we enriched for three consortia that were capable of quickly degrading OMP, BMP and BMIM. Our results indicate WWTPs are not functionally redundant with regard to biodegradation of specific ionic liquids. However, consortia can be enriched to degrade chemicals that fail biodegradability assays. This information can be used to prepare pre-treatment procedures and prevent environmental release of novel pollutants. PMID:25985304

  2. Spatial-decomposition analysis of electrical conductivity in ionic liquid.

    PubMed

    Tu, Kai-Min; Ishizuka, Ryosuke; Matubayasi, Nobuyuki

    2014-12-28

    The electrical conductivity of room temperature ionic liquid (IL) is investigated with molecular dynamics simulation. A trajectory of 1??s in total is analyzed for the ionic liquid [C4mim][NTf2] (1-n-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, and the anion is also called TFSI or TFSA), and the ion motions are examined in direct connection to the conductivity within the framework formulated previously [K.-M. Tu, R. Ishizuka, and N. Matubayasi, J. Chem. Phys. 141, 044126 (2014)]. As a transport coefficient, the computed electrical conductivity is in fair agreement with the experiment. The conductivity is then decomposed into the autocorrelation term of Nernst-Einstein form and the cross-correlation term describing the two-body motions of ions, and the cross-correlation term is further decomposed spatially to incorporate the structural insights on ion configurations into the dynamic picture. It is observed that the ion-pair contribution to the conductivity is not spatially localized and extends beyond the first coordination shell. The extent of localization of the cross-correlation effect in the conductivity is in correspondence to that of the spatial correlation represented by radial distribution function, which persists over nanometer scale. PMID:25554167

  3. Ionic liquids adsorbed cellulose electro active paper actuator

    NASA Astrophysics Data System (ADS)

    Mahadeva, Suresha K.; Nayak, Jyoti; Kim, Jaehwan

    2009-03-01

    Cellulose has been reported as a smart material that can be used as sensors and actuators. The cellulose smart material is termed as Electro-active paper (EAPap), which is made by regenerating cellulose. However, regeneration of cellulose resulted in reduced performance output of actuators at low humidity levels. To solve this drawback, EAPap bending actuators were made by activating wet cellulose films in three different room temperature ionic liquids BMIPF6, BMICL and BMIBF4. Results showed that the actuator performance was dependent on the type of anions in the ionic liquids and it was in the order of BF4 > Cl > PF6Â. BMIBF4 activated actuator showed the maximum displacement of 3.8 mm with low electrical power consumption at relatively low humidity level. Also, it found that, although size of PF6 anion is larger than BF4 anion it showed the low displacement output due to poor adsorption as indicated the FTIR analysis.

  4. Ionic liquid-based liquid phase microextraction with direct injection for capillary electrophoresis.

    PubMed

    Breadmore, Michael C

    2011-03-11

    Liquid-liquid microextraction using the water immiscible ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, EMIM NtfO?, for the concentration and cleanup of basic compounds for analysis by CE has been investigated. Using an electrolyte comprising 1 mol/L alanine and 3 mol/L acetic acid, EMIM NtfO? could be directly injected into the capillary after liquid phase extraction. Using the basic dye chryisoidine, sensitivity enhancements approaching 1000-fold were obtained by mixing 20 ?L of EMIM NtfO? with 1500 ?L of aqueous sample, leaving only 5 ?L of the undissolved ionic liquid which was used for injection into the CE. Lower more repeatable enhancement factors of 200-fold were obtained with slightly larger initial 25 ?L volumes of EMIM NtfO? due to the larger residual volume of ionic liquid which made handling easier. This could be extended to basic pharmaceuticals, and the extraction of clozapine and its two active metabolites, nor-clozapine and clozapine-N-oxide, was demonstrated from urine with enrichment factors greater than 100 obtained. Handling of potentially more dangerous samples, such as serum, through in-vial extraction of clozapine and its metabolites and direct injection of the ionic liquid layer was also demonstrated with enhancements in sensitivity of 80. Limits of detection from 3 to 11 ?g/L and 6 to 55 ?g/L were obtained from urine and serum, respectively, which are sufficiently low to be useful for the determination of these pharmaceuticals clinically for therapeutic drug monitoring and for forensic toxicology. PMID:21277579

  5. Metal-air cell comprising an electrolyte with a room temperature ionic liquid and hygroscopic additive

    DOEpatents

    Friesen, Cody A.; Krishnan, Ramkumar; Tang, Toni; Wolfe, Derek

    2014-08-19

    An electrochemical cell comprising an electrolyte comprising water and a hydrophobic ionic liquid comprising positive ions and negative ions. The electrochemical cell also includes an air electrode configured to absorb and reduce oxygen. A hydrophilic or hygroscopic additive modulates the hydrophobicity of the ionic liquid to maintain a concentration of the water in the electrolyte is between 0.001 mol % and 25 mol %.

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

    DOEpatents

    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.

  7. Thermochromism and switchable paramagnetism of cobalt(ii) in thiocyanate ionic liquids.

    PubMed

    Osborne, Stephen J; Wellens, Sil; Ward, Chris; Felton, Solveig; Bowman, Robert M; Binnemans, Koen; Swad?ba-Kwa?ny, Ma?gorzata; Gunaratne, H Q Nimal; Nockemann, Peter

    2015-06-17

    Temperature-dependent switching of paramagnetism of a cobalt(ii) complex is observed in an ionic liquid solution. Paramagnetic and thermochromic switching occur simultaneously due to a reversible change in coordination. This reversible switching is possible in the ionic liquid solution, which enables mobility of thiocyanate anions by remaining mobile at low temperatures and acts as an anion reservoir. PMID:26053484

  8. A "by-productless" cellulose foaming agent for use in imidazolium ionic liquids.

    PubMed

    Scott, Janet L; Unali, Gianfranco; Perosa, Alvise

    2011-03-14

    Cellulose foams, or sponges, are produced from solutions in ionic liquids by the aqueous acid mediated decomposition of 1-alkyl-3-methylimidazolium-2-carboxylates, where the alkyl group and acid may be selected such that the by-product is the ionic liquid solvent: a by-productless foaming. PMID:21243139

  9. Ionic liquids as passive monitors of an atmosphere rich in mercury

    Microsoft Academic Search

    M. A. Martínez; C. Solis; E. Andrade; M. A. Mondragón; K. Isaac-Olivé; M. F. Rocha

    An ionic liquid (IL) is a compound at dynamical equilibrium in which at any time more than 99.99% of it is shifted toward the ionic rather than the molecular species. ILs have raised considerable attention during the past few years due to their extremely low vapor pressure, good electrolytic properties and wide electrochemical window. Also, they remain liquid at a

  10. The Tribological Properties of Ionic Liquids and Their Improvement by Additives

    NASA Astrophysics Data System (ADS)

    Minami, Ichiro; Mori, Shigeyuki

    The tribological properties of ionic liquids are outlined in terms of their chemical structure. Advantages of imidazolium cation and bis (tetrafluoromethylsulfonyl) imide are pointed out. Improvement in the tribological properties is possible by applying additives such as simple carboxylic acids. Requirements in ionic liquids as advanced lubricants are outlined.

  11. Evaluation of Vapor Pressure and UltraHigh Vacuum Tribological Properties of Ionic Liquids

    Microsoft Academic Search

    Wilfredo Morales; Victor R. Koch; Daniel J. Valco; Ryan M. Richard; Nicole Hanks

    2011-01-01

    Ionic liquids are a class of salts that incorporate polyatomic anions and cations. These materials are typically viscous fluids at room temperature. The fluids are generally characterized as possessing negligible vapor pressures under ambient conditions. These beneficial properties have led us to study the effectiveness of ionic liquids containing both organic cations and anions for use as lubricants with space

  12. The Tribological Properties of Ionic Liquids and Their Improvement by Additives

    Microsoft Academic Search

    Ichiro Minami; Shigeyuki Mori

    2008-01-01

    The tribological properties of ionic liquids are outlined in terms of their chemical structure. Advantages of imidazolium cation and bis (tetrafluoromethylsulfonyl) imide are pointed out. Improvement in the tribological properties is possible by applying additives such as simple carboxylic acids. Requirements in ionic liquids as advanced lubricants are outlined.

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

    SciTech Connect

    Dai, Sheng [ORNL; Luo, Huimin [ORNL; Wang, Congmin [ORNL; Li, Haoran [Zhejiang University

    2010-01-01

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

  14. Exploration of Ionic Liquids as Soluble Supports for Organic Synthesis. Demonstration with a Suzuki Coupling Reaction

    Microsoft Academic Search

    Weishi Miao; Tak Hang Chan

    2003-01-01

    The efficiency of ionic liquid supported synthesis was demonstrated by the Suzuki reaction of ionic liquid supported iodobenzoate compounds with arylboronic acids in aqueous media to give, after cleavage with ammonia\\/methanol, biaryl products in good yields and high purities, without the need for chromatographic purification.

  15. Dynamics of Isolated Water Molecules in a Sea of Ions in a Room Temperature Ionic Liquid

    E-print Network

    Fayer, Michael D.

    Dynamics of Isolated Water Molecules in a Sea of Ions in a Room Temperature Ionic Liquid Daryl B2O molecules in the room temperature ionic liquid (RTIL) 1-butyl-3-methylimidazolium resolved in the IR absorption spectrum in spite of the fact that the D2O is surrounded by a sea of ions

  16. Comparison of different advanced oxidation processes for the degradation of room temperature ionic liquids

    Microsoft Academic Search

    Piotr Stepnowski; Adriana Zaleska

    2005-01-01

    Imidazolium ionic liquids have been widely researched as possible “green” replacements for organic solvents. The “green” aspect is related mainly to their non-measurable vapor pressure, which is obviously not enough to justify calling a technology cleaner. Some quantities of ionic liquids will soon be present in technological wastewater, where, because of their great stability, they could become persistent pollutants and

  17. Lyotropic liquid crystal phases of phytantriol in a protic ionic liquid with fluorous anion.

    PubMed

    Shen, Yan; Greaves, Tamar L; Kennedy, Danielle F; Weerawardena, Asoka; Kirby, Nigel; Song, Gonghua; Drummond, Calum J

    2014-10-21

    The phase behaviour of phytantriol in the protic ionic liquid (PIL) 1-methylimidazolium pentadecafluorooctanoate (MImOF) and four different MImOF-water compositions was investigated by small- and wide-angle X-ray scattering (SAXS/WAXS), cross polarised optical microscopy (CPOM) and infrared spectroscopy (IR). MImOF is a distinct protic ionic liquid in that it contains a fluorocarbon anion and a hydrocarbon cation. This leads to MImOF having an unusual liquid nanostructure, such that it contains fluorocarbon, hydrocarbon and polar domains. No lyotropic liquid crystal phases were observed for phytantriol in neat MImOF. However, on addition of water, lamellar, cubic Ia3¯d and micellar phases were observed for specific MImOF-phytantriol-water compositions at room temperature, and up to 60 °C. The phase behaviour for phytantriol in the solvent mixture of 25 wt%-MImOF-75 wt%-water was the most similar to the phytantriol-water phase diagram. Only this MImOF-water composition supported the Ia3¯d cubic phase, which had a lattice parameter between 100-140 Å compared to 86-100 Å in deionised water, indicating significant swelling due to the MImOF. IR spectroscopy showed that a percentage of the water molecules were hydrogen bonded to the N-H of the MIm cation, and this water decreased the hydrogen bonding present between the cation and anion of the ionic liquid. This investigation furthers our understanding of the interaction of ionic liquids with solutes, and the important role that the different IL nanostructures can have on influencing these interactions. PMID:25177837

  18. A classical density functional theory for interfacial layering of ionic liquids

    SciTech Connect

    Wu, Jianzhong [University of California, Riverside; Jiang, Tao [California Energy Commission; Jiang, Deen [ORNL; Jin, Zhehui [University of California, Riverside; Henderson, Douglous [Brigham Young University

    2011-01-01

    Ionic liquids have attracted much recent theoretical interest for broad applications as environmentally-friendly solvents in separation and electrochemical processes. Because of the intrinsic complexity of organic ions and strong electrostatic correlations, the electrochemical properties of ionic liquids often defy the descriptions of conventional mean-field methods including the venerable, and over-used, Gouy-Chapman-Stern (GCS) theory. Classical density functional theory (DFT) has proven to be useful in previous studies of the electrostatic properties of aqueous electrolytes but until recently it has not been applied to ionic liquids. Here we report predictions from the DFT on the interfacial properties of ionic liquids near neutral or charged surfaces. By considering the molecular size, topology, and electrostatic correlations, we have examined major factors responsible for the unique features of electric-double layers of ionic-liquid including formation of long-range and alternating structures of cations and anions at charged surfaces.

  19. A classical density functional theory for interfacial layering of ionic liquids

    SciTech Connect

    Wu, Jianzhong [Univ. Of California, Riverside, CA (United States); Jiang, Tao [Univ. Of California, Riverside, CA (United States); California Energy Commission, Sacramento, CA (United States); Jiang, De-en [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Jin, Zhehui [Univ. Of California, Riverside, CA (United States); Henderson, Douglas [Brigham Young Univ., Provo, UT (United States)

    2011-01-01

    Ionic liquids have attracted much recent theoretical interest for broad applications as environmentally-friendly solvents in separation and electrochemical processes. Because of the intrinsic complexity of organic ions and strong electrostatic correlations, the electrochemical properties of ionic liquids often defy the descriptions of conventional mean-field methods including the venerable, and over-used, Gouy–Chapman–Stern (GCS) theory. Classical density functional theory (DFT) has proven to be useful in previous studies of the electrostatic properties of aqueous electrolytes but until recently it has not been applied to ionic liquids. Here we report predictions from the DFT on the interfacial properties of ionic liquids near neutral or charged surfaces. By considering the molecular size, topology, and electrostatic correlations, we have examined major factors responsible for the unique features of electric-double layers of ionic-liquid including formation of long-range and alternating structures of cations and anions at charged surfaces.

  20. Atomic-scale characterization of oxide thin films gated by ionic liquid.

    PubMed

    Lang, Andrew C; Sloppy, Jennifer D; Ghassemi, Hessam; Devlin, Robert C; Sichel-Tissot, Rebecca J; Idrobo, Juan-Carlos; May, Steven J; Taheri, Mitra L

    2014-10-01

    Ionic liquids (ILs) have received considerable interest for use in electrostatic gating in complex oxide systems. Understanding the ionic liquid/oxide interface, and any bias-induced electrochemical degradation, is critical for the interpretation of transport phenomena. The integrity of the interface between ionic liquid 1-ethyl-3-methylimidazolium hexafluorophosphate and La1/3Sr2/3FeO3 under various biasing conditions was examined by analytical transmission electron microscopy, and we report film degradation in the form of an irreversible chemical reaction regardless of the applied bias. This results in an intermixing region of 4-6 nm at the IL/oxide interface. Electron energy loss spectroscopy shows La and Fe migration into the ionic liquid, resulting in secondary phase formation under negative bias. Our approach can be extended to other ionic liquid/oxide systems in order to better understand the electrochemical stability window of these device structures. PMID:25188384

  1. Mutual Lewis Acid–Base Interactions of Cations and Anions in Ionic Liquids

    PubMed Central

    Holzweber, Markus; Lungwitz, Ralf; Doerfler, Denise; Spange, Stefan; Koel, Mihkel; Hutter, Herbert; Linert, Wolfgang

    2013-01-01

    Solute properties are known to be strongly influenced by solvent molecules due to solvation. This is due to mutual interaction as both the properties of the solute and of the solvent strongly depend on each other. The present paper is based on the idea that ionic liquids are cations solvated by anions and anions solvated by cations. To show this (in this system strongly pronounced) interaction the long time established donor–acceptor concept for solvents and ions in solution by Viktor Gutmann is extended to ionic liquids. A number of solvent parameters, such as the Kamlet–Abboud–Taft and the Dimroth–Reichardt ET scale for ionic liquids neglect this mutual influence, which, however, seems to be in fact necessary to get a proper description of ionic liquid properties. It is shown how strong such parameters vary when the influence of the counter ion is taken into account. Furthermore, acceptor and donor numbers for ionic liquids are presented. PMID:23180598

  2. Oxidative desulfurization of fuel oil by pyridinium-based ionic liquids.

    PubMed

    Zhao, Dishun; Wang, Yanan; Duan, Erhong

    2009-01-01

    In this work, an N-butyl-pyridinium-based ionic liquid [BPy]BF(4) was prepared. The effect of extraction desulfurization on model oil with thiophene and dibenzothiophene (DBT) was investigated. Ionic liquids and hydrogen peroxide (30%) were tested in extraction-oxidation desulfurization of model oil. The results show that the ionic liquid [BPy]BF(4) has a better desulfurization effect. The best technological conditions are: V(IL)/V(Oil) /V(H(2)O(2)) = 1:1:0.4, temperature 55 degrees C, the time 30 min. The ratio of desulfurization to thiophene and DBT reached 78.5% and 84.3% respectively, which is much higher than extraction desulfurization with simple ionic liquids. Under these conditions, the effect of desulfurization on gasoline was also investigated. The used ionic liquids can be recycled up to four times after regeneration. PMID:19924069

  3. Room temperature ionic liquid 1-ethyl-3-hexylimidazolium-bis(trifluoromethylsulfonyl)-imide as lubricant for steel–steel contact

    Microsoft Academic Search

    Qiming Lu; Haizhong Wang; Chengfeng Ye; Weimin Liu; Qunji Xue

    2004-01-01

    The ionic liquid 1-ethyl-3-hexylimidazolium-bis(trifluoromethylsulfonyl)-imide was synthesized and evaluated as lubricant for the contact of steel\\/steel. The tribological properties of the ionic liquid as lubricant were investigated on an Optimol SRV oscillating friction and wear tester in ambient condition. The synthetic ionic liquid shows excellent tribological performance and is superior to the ionic liquid of alkylimidazolium tetrafluoroborate and the conventional high

  4. Magnetomotive room temperature dicationic ionic liquid: a new concept toward centrifuge-less dispersive liquid-liquid microextraction.

    PubMed

    Beiraghi, Asadollah; Shokri, Masood; Seidi, Shahram; Godajdar, Bijan Mombani

    2015-01-01

    A new centrifuge-less dispersive liquid-liquid microextraction technique based on application of magnetomotive room temperature dicationic ionic liquid followed by electrothermal atomic absorption spectrometry (ETAAS) was developed for preconcentration and determination of trace amount of gold and silver in water and ore samples, for the first time. Magnetic ionic liquids not only have the excellent properties of ionic liquids but also exhibit strong response to an external magnetic field. These properties provide more advantages and potential application prospects for magnetic ionic liquids than conventional ones in the fields of extraction processes. In this work, thio-Michler's ketone (TMK) was used as chelating agent to form Ag/Au-TMK complexes. Several important factors affecting extraction efficiency including extraction time, rate of vortex agitator, pH of sample solution, concentration of the chelating agent, volume of ionic liquid as well as effects of interfering species were investigated and optimized. Under the optimal conditions, the limits of detection (LOD) were 3.2 and 7.3ngL(-1) with the preconcentration factors of 245 and 240 for Au and Ag, respectively. The precision values (RSD%, n=7) were 5.3% and 5.8% at the concentration level of 0.05?gL(-1) for Au and Ag, respectively. The relative recoveries for the spiked samples were in the acceptable range of 96-104.5%. The results demonstrated that except Hg(2+), no remarkable interferences are created by other various ions in the determination of Au and Ag, so that the tolerance limits (WIon/WAu or Ag) of major cations and anions were in the range of 250-1000. The validated method was successfully applied for the analysis of Au and Ag in some water and ore samples. PMID:25528072

  5. Contracting cardiomyocytes in hydrophobic room-temperature ionic liquid

    SciTech Connect

    Hoshino, Takayuki [Department of Mechanical Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan) [Department of Mechanical Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Department of Bio-Application and System Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei-shi, Tokyo 184-8588 (Japan); Fujita, Kyoko [Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei-shi, Tokyo 184-8588 (Japan)] [Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei-shi, Tokyo 184-8588 (Japan); Higashi, Ayako; Sakiyama, Keiko [Department of Bio-Application and System Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei-shi, Tokyo 184-8588 (Japan)] [Department of Bio-Application and System Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei-shi, Tokyo 184-8588 (Japan); Ohno, Hiroyuki [Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei-shi, Tokyo 184-8588 (Japan)] [Department of Biotechnology, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei-shi, Tokyo 184-8588 (Japan); Morishima, Keisuke, E-mail: morishima@mech.eng.osaka-u.ac.jp [Department of Mechanical Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan) [Department of Mechanical Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Department of Bio-Application and System Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei-shi, Tokyo 184-8588 (Japan)

    2012-10-19

    Highlights: Black-Right-Pointing-Pointer Biocompatible room-temperature ionic liquid was applied on beating cardiomyocyte. Black-Right-Pointing-Pointer The lifetime of beating cardiomyocytes was depended on anion functional group. Black-Right-Pointing-Pointer A longer lifetime was recorded for no functional group on alkyl chain on their anion. Black-Right-Pointing-Pointer Amino group on alkyl chain and fluorine in anion induced fatal condition changes. Black-Right-Pointing-Pointer We reported liquid electrolyte interface to stimulate cardiomyocytes. -- Abstract: Room-temperature ionic liquids (RTILs) are drawing attention as a new class of nonaqueous solvents to replace organic and aqueous solvents for chemical processes in the liquid phase at room temperature. The RTILs are notable for their characteristics of nonvolatility, extremely low vapor pressure, electric conductivity, and incombustibility. These distinguished properties of RTILs have brought attention to them in applications with biological cells and tissue in vacuum environment for scanning electron microscopy, and in microfluidic devices for micro-total analysis system (micro-TAS). Habitable RTILs could increase capability of nonaqueous micro-TAS for living cells. Some RTILs seemed to have the capability to replace water in biological applications. However, these RTILs had been applied to just supplemental additives for biocompatible test, to fixed cells as a substitute for an aqueous solution, and to simple molecules. None of RTILs in which directly soaks a living cell culture. Therefore, we demonstrated the design of RTILs for a living cell culture and a liquid electrolyte to stimulate contracting cardiomyocytes using the RTILs. We assessed the effect of RTILs on the cardiomyocytes using the beating lifetime to compare the applicability of RTILs for biological applications. Frequent spontaneous contractions of cardiomyocytes were confirmed in amino acid anion RTILs [P{sub 8,8,8,8}][Leu] and [P{sub 8,8,8,8}][Ala], phosphoric acid derivatives [P{sub 8,8,8,8}][MeO(H)PO{sub 2}], and [P{sub 8,8,8,8}][C{sub 7}CO{sub 2}]. The anion type of RTILs had influence on applicable characteristics for the contracting cardiomyocyte. This result suggested the possibility for biocompatible design of hydrophobic group RTILs to achieve biological applications with living cells.

  6. Theoretical studies on the electronic States and liquid structures of ferrocenium-based ionic liquids.

    PubMed

    Nakano, Hiroshi; Noguchi, Junki; Mochida, Tomoyuki; Sato, Hirofumi

    2015-05-28

    The solvation effects on the electronic structures and magnetic properties were computed for a series of ferrocenium cations in the ferrocenium-based ionic liquids using RISM-SCF-SEDD calculations coupled with CASSCF. The spin-orbit coupling was calculated to get insight into the spin anisotropy. The values were on the order of 100 cm(-1), exhibiting strong spin anisotropy parallel to the angular momentum. The computed results show that the magnetic properties of the ferrocenium cations are similar both in the isolated state and in ionic liquids. We also carried out molecular dynamics and RISM calculations to investigate the liquid structures. The radial and spatial distribution functions around the cations indicate that the cations are surrounded by about seven TFSA anions above and below the cyclopentadienyl rings and from the side of the ferrocenium cations. The nearest-neighbor cations exist in the oblique directions. The introduction of a butyl group to the ring disturbs the solvation structures, and butyl groups in different cations tend to attract each other like those observed in alkylimidazolium ionic liquids. PMID:25517686

  7. Click grafting of seaweed bioactive polysaccharides onto PVC surfaces using ionic liquid as green solvent and catalyst

    E-print Network

    Boyer, Edmond

    Click grafting of seaweed bioactive polysaccharides onto PVC surfaces using ionic liquid as green polysaccharides were then directly grafted onto the PVC-NCS surface using ionic liquid as solvent and catalyst: PVC, ionic liquid, polysaccharides, click chemistry. hal-00908526,version1-24Nov2013 Author manuscript

  8. Ion transport and softening in a polymerized ionic liquid.

    PubMed

    Kumar, Rajeev; Bocharova, Vera; Strelcov, Evgheni; Tselev, Alexander; Kravchenko, Ivan I; Berdzinski, Stefan; Strehmel, Veronika; Ovchinnikova, Olga S; Minutolo, Joseph A; Sangoro, Joshua R; Agapov, Alexander L; Sokolov, Alexei P; Kalinin, Sergei V; Sumpter, Bobby G

    2015-01-21

    Polymerized ionic liquids (PolyILs) are promising materials for various solid state electronic applications such as dye-sensitized solar cells, lithium batteries, actuators, field-effect transistors, light emitting electrochemical cells, and electrochromic devices. However, fundamental understanding of interconnection between ionic transport and mechanical properties in PolyILs is far from complete. In this work, local charge transport and structural changes in films of a PolyIL are studied using an integrated experiment-theory based approach. Experimental data for the kinetics of charging and steady state current-voltage relations can be explained by taking into account the dissociation of ions under an applied electric field (known as the Wien effect). Onsager's theory of the Wien effect coupled with the Poisson-Nernst-Planck formalism for the charge transport is found to be in excellent agreement with the experimental results. The agreement between the theory and experiments allows us to predict structural properties of the PolyIL films. We have observed significant softening of the PolyIL films beyond certain threshold voltages and formation of holes under a scanning probe microscopy (SPM) tip, through which an electric field was applied. The observed softening is explained by the theory of depression in glass transition temperature resulting from enhanced dissociation of ions with an increase in applied electric field. PMID:25463322

  9. Ferrocenyl-phosphonium ionic liquids - synthesis, characterisation and electrochemistry.

    PubMed

    Kübler, Paul; Sundermeyer, Jörg

    2014-03-01

    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. PMID:24441282

  10. Stable prenucleation mineral clusters are liquid-like ionic polymers.

    PubMed

    Demichelis, Raffaella; Raiteri, Paolo; Gale, Julian D; Quigley, David; Gebauer, Denis

    2011-01-01

    Calcium carbonate is an abundant substance that can be created in several mineral forms by the reaction of dissolved carbon dioxide in water with calcium ions. Through biomineralization, organisms can harness and control this process to form various functional materials that can act as anything from shells through to lenses. The early stages of calcium carbonate formation have recently attracted attention as stable prenucleation clusters have been observed, contrary to classical models. Here we show, using computer simulations combined with the analysis of experimental data, that these mineral clusters are made of an ionic polymer, composed of alternating calcium and carbonate ions, with a dynamic topology consisting of chains, branches and rings. The existence of a disordered, flexible and strongly hydrated precursor provides a basis for explaining the formation of other liquid-like amorphous states of calcium carbonate, in addition to the non-classical behaviour during growth of amorphous calcium carbonate. PMID:22186886

  11. Ionic liquid-based green processes for energy production.

    PubMed

    Zhang, Suojiang; Sun, Jian; Zhang, Xiaochun; Xin, Jiayu; Miao, Qingqing; Wang, Jianji

    2014-11-21

    To mitigate the growing pressure on resource depletion and environment degradation, the development of green processes for the production of renewable energy is highly required. As a class of novel and promising media, ionic liquids (ILs) have shown infusive potential applications in energy production. Aiming to offer a critical overview regarding the new challenges and opportunities of ILs for developing green processes of renewable energy, this article emphasises the role of ILs as catalysts, solvents, or electrolytes in three broadly interesting energy production processes from renewable resources, such as CO2 conversion to fuels and fuel additives, biomass pretreatment and conversion to biofuels, as well as solar energy and energy storage. It is expected that this article will stimulate a generation of new ideas and new technologies in IL-based renewable energy production. PMID:24553494

  12. Cyanoborohydride-based ionic liquids as green aerospace bipropellant fuels.

    PubMed

    Zhang, Qinghua; Yin, Ping; Zhang, Jiaheng; Shreeve, Jean'ne M

    2014-06-01

    In propellant systems, the most common bipropellants are composed of two chemicals, a fuel (or reducer) and an oxidizer. Currently, the choices for propellant fuels rely mainly on hydrazine and its methylated derivatives, even though they are extremely toxic, highly volatile, sensitive to adiabatic compression (risk of detonation), and, therefore, difficult to handle. With this background, the search for alternative green propellant fuels has been an urgent goal of space science. In this study, a new family of cyanoborohydride-based ionic liquids (ILs) with properties and performances comparable to hydrazine derivatives were designed and synthesized. These new ILs as bipropellant fuels, have some unique advantages including negligible vapor pressure, ultra-short ignition delay (ID) time, and reduced synthetic and storage costs, thereby showing great application potential as environmentally friendly fuels in bipropellant formulations. PMID:24737218

  13. Abstraction of Nano Copper in a Room Temperature Ionic Liquid

    SciTech Connect

    Peng, C. Y.; Huang, C. H. [Department of Environmental Engineering, National Cheng Kung University, Tainan City, Taiwan (China); Wang, H. Paul [Department of Environmental Engineering, National Cheng Kung University, Tainan City, Taiwan (China); Sustainable Environment Research Center, National Cheng Kung University, Tainan City, Taiwan (China); Wei Yuling [Department of Environmental Science and Engineering, TungHai University, Taichung City, Taiwan (China)

    2007-02-02

    Speciation of copper in the abstraction of nano copper with a room temperature ionic liquid (RTIL) (1-butyl-3-methylimidazolium hexafluorophosphate [C4mim][PF6]) has been studied by X-ray absorption near edge structural (XANES) and extended X-ray absorption fine structural (EXAFS) spectroscopies in the present work. The least-square fits of the XANES spectra suggest that nano CuO (79%) and Cu(II) complex (Cu(II)-IL) (21%) are the main copper species in the RTIL. The fitted EXAFS spectra show that the Cu-O (1st shell) bond distance is 2.08 A with a coordination number (CN) of 2.6. In the second shells of copper, the average bond distance of Cu-Cu is 2.99 A with a CN of 5.1.

  14. Diamino protic ionic liquids for CO2 capture.

    PubMed

    Vijayraghavan, R; Pas, Steven J; Izgorodina, Ekaterina I; MacFarlane, Douglas R

    2013-12-14

    A series of multifunctional protic ionic liquids (PILs), some of which are based on a combination of primary and tertiary amines in the same moiety coupled with a carboxylic acid, have been synthesised and employed for CO2 capture, yielding absorption capacities comparable to standard absorbents. In contrast to traditional amine absorbers, CO2 was found to desorb at lower temperatures and hence could result in a significant reduction in both the energy required to strip the absorber of CO2 and the thermally activated degradation mechanisms, which in traditional absorbers result in the loss of absorber and the production of toxic compounds. The lower basicity of the amine sites resultant from PIL formation decreases the binding energy of the CO2 to the absorber. The weaker basicity is also evidenced by lower pH of the PIL CO2 absorbers, which reduces common corrosion problems associated with traditional amine absorbers. PMID:24162803

  15. Multiple headspace extraction for gas detection in ionic liquids.

    PubMed

    Müller, D; Fühl, M; Pinkwart, K; Baltes, N

    2014-10-16

    In this study multiple headspace extraction was used for the first time to measure the saturation concentration of carbon monoxide and oxygen in various ionic liquids (ILs). Many processes in ILs involve the reaction of gases so that the reactant solubility is not a mere characteristical parameter, but understanding the solubility of gases in ILs is required for assessing the feasibility of possible applications. Multiple headspace extraction has proofed to be a powerful tool to obtain solubilities in good accordance with literature data. The measured saturation concentration for carbon monoxide and oxygen in ILs based on rarely researched tetracyanoborates and other anions was in the range of 1.5-6.5mmol/L. The great advantage of multiple headspace extraction is that it is a nonexpensive method that can be realised in most analytical laboratories by combination of a simple gas chromatograph and an eligible headspace injector. PMID:25458524

  16. 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

    2015-05-01

    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. PMID:25893981

  17. Protein Structure and Stability in Neat Ionic Liquid

    NASA Astrophysics Data System (ADS)

    Bihari, Malvika; Russell, Thomas P.; Hoagland, David A.

    2010-03-01

    Ionic liquid (IL) as a medium for room temperature preservation of biomacromolecules has been proposed, and to investigate the possibility, we studied physicochemical and enzymatic properties of several proteins in the neat hydrophilic IL, ethylmethyl imidazolium ethyl sulfate [EMIM][EtSO4]. Molecular dissolution of ?-chymotypsin, cytochrome-c and other proteins could be achieved with moderate heating (60C). Dynamic light scattering and dilute solution viscometry typically reveal protein size slightly larger than in buffer, suggesting different solvation or protein unfolding. Spectroscopic methods (UV-Vis, fluorescence, FTIR, CD) show largely unchanged secondary structure but significantly changed tertiary structure. IL-dissolved cytochrome-c has heightened peroxidase activity, supporting the same conclusions. Transfer of dissolved protein from IL to buffer and ensuing alterations to protein conformation/activity will be discussed.

  18. Tunable wavelength soft photoionization of ionic liquid vapors

    SciTech Connect

    Strasser, Daniel; Goulay, Fabien; Belau, Leonid; Kostko, Oleg; Koh, Christine; Chambreau, Steven D.; Vaghjiani, Ghanshyam L.; Ahmed, Musahid; Leone, Stephen R.

    2009-11-11

    Combined data of photoelectron spectra and photoionization efficiency curves in the near threshold ionization region of isolated ion-pairs from [emim][Tf2N], [emim][Pf2N]and [dmpim][Tf2N]ionic liquid vapors reveal small shifts in the ionization energies of ion-pair systems due to cation and anion substitutions. Shifts towards higher binding energy following anion substitution are attributed to increased electronegativity of the anion itself, while shifts towards lower binding energies following cation substitution are attributed to an increase in the cation-anion distance that causes a lower Coulombic binding potential. The predominant ionization mechanism in the near threshold photon energy region is identified as dissociative ionization, involving dissociation of the ion-pair and the production of intact cations as the positively charged products.

  19. Development of regenerated cellulose/halloysites nanocomposites via ionic liquids.

    PubMed

    Hanid, Nurbaiti Abdul; Wahit, Mat Uzir; Guo, Qipeng; Mahmoodian, Shaya; Soheilmoghaddam, Mohammad

    2014-01-01

    In this study, regenerated cellulose/halloysites (RC/HNT) nanocomposites with different nanofillers loading were fabricated by dissolving the cellulose in 1-ethyl-3-methylimidazolium chloride (EMIMCl) ionic liquid. The films were prepared via solution casting method and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The mechanical properties were investigated by tensile testing. It clearly displayed a good enhancement of both tensile strength and Young's modulus with HNT loading up to 5 wt%. As the HNT loadings increased to 5 wt%, the thermal behaviour and water resistance rate was also increased. The TEM and SEM images also depicted even dispersion of the HNT and a good intertubular interaction between the HNT and the cellulose matrix. PMID:24274483

  20. Nonlinear polarization of ionic liquids: theory, simulations, experiments

    NASA Astrophysics Data System (ADS)

    Kornyshev, Alexei

    2010-03-01

    Room temperature ionic liquids (RTILs) composed of large, often asymmetric, organic cations and simple or complex inorganic or organic anions do not freeze at ambient temperatures. Their rediscovery some 15 years ago is widely accepted as a ``green revolution'' in chemistry, offering an unlimited number of ``designer'' solvents for chemical and photochemical reactions, homogeneous catalysis, lubrication, and solvent-free electrolytes for energy generation and storage. As electrolytes they are non-volatile, some can sustain without decomposition up to 6 times higher voltages than aqueous electrolytes, and many are environmentally friendly. The studies of RTILs and their applications have reached a critical stage. So many of them can be synthesized - about a thousand are known already - their mixtures can further provide ``unlimited'' number of combinations! Thus, establishing some general laws that could direct the best choice of a RTIL for a given application became crucial; guidance is expected from theory and modelling. But for a physical theory, RTILs comprise a peculiar and complex class of media, the description of which lies at the frontier line of condensed matter theoretical physics: dense room temperature ionic plasmas with ``super-strong'' Coulomb correlations, which behave like glasses at short time-scale, but like viscous liquids at long-time scale. This talk will introduce RTILs to physicists and overview the current understanding of the nonlinear response of RTILs to electric field. It will focus on the theory, simulations, and experimental characterisation of the structure and nonlinear capacitance of the electrical double layer at a charged electrode. It will also discuss pros and contras of supercapacitor applications of RTILs.

  1. Evaluation of four ionic liquids for pretreatment of lignocellulosic biomass

    PubMed Central

    2014-01-01

    Background Lignocellulosic biomass is highly recalcitrant and various pretreatment techniques are needed to facilitate its effective enzymatic hydrolysis to produce sugars for further conversion to bio-based chemicals. Ionic liquids (ILs) are of interest in pretreatment because of their potential to dissolve lignocellulosic materials including crystalline cellulose. Results Four imidazolium-based ionic liquids (ILs) ([C=C2C1im][MeCO2], [C4C1im][MeCO2], [C4C1im][Cl], and [C4C1im][HSO4]) well known for their capability to dissolve lignocellulosic species were synthesized and then used for pretreatment of substrates prior to enzymatic hydrolysis. In order to achieve a broad evaluation, seven cellulosic, hemicellulosic and lignocellulosic substrates, crystalline as well as amorphous, were selected. The lignocellulosic substrates included hybrid aspen and Norway spruce. The monosaccharides in the enzymatic hydrolysate were determined using high-performance anion-exchange chromatography. The best results, as judged by the saccharification efficiency, were achieved with [C4C1im][Cl] for cellulosic substrates and with the acetate-based ILs for hybrid aspen and Norway spruce. After pretreatment with acetate-based ILs, the conversion to glucose of glucan in recalcitrant softwood lignocellulose reached similar levels as obtained with pure crystalline and amorphous cellulosic substrates. IL pretreatment of lignocellulose resulted in sugar yields comparable with that obtained with acidic pretreatment. Heterogeneous dissolution with [C4C1im][HSO4] gave promising results with aspen, the less recalcitrant of the two types of lignocellulose included in the investigation. Conclusions The ability of ILs to dissolve lignocellulosic biomass under gentle conditions and with little or no by-product formation contributes to making them highly interesting alternatives for pretreatment in processes where high product yields are of critical importance. PMID:24779378

  2. Ion transport and softening in a polymerized ionic liquid

    NASA Astrophysics Data System (ADS)

    Kumar, Rajeev; Bocharova, Vera; Strelcov, Evgheni; Tselev, Alexander; Kravchenko, Ivan I.; Berdzinski, Stefan; Strehmel, Veronika; Ovchinnikova, Olga S.; Minutolo, Joseph A.; Sangoro, Joshua R.; Agapov, Alexander L.; Sokolov, Alexei P.; Kalinin, Sergei V.; Sumpter, Bobby G.

    2014-12-01

    Polymerized ionic liquids (PolyILs) are promising materials for various solid state electronic applications such as dye-sensitized solar cells, lithium batteries, actuators, field-effect transistors, light emitting electrochemical cells, and electrochromic devices. However, fundamental understanding of interconnection between ionic transport and mechanical properties in PolyILs is far from complete. In this work, local charge transport and structural changes in films of a PolyIL are studied using an integrated experiment-theory based approach. Experimental data for the kinetics of charging and steady state current-voltage relations can be explained by taking into account the dissociation of ions under an applied electric field (known as the Wien effect). Onsager's theory of the Wien effect coupled with the Poisson-Nernst-Planck formalism for the charge transport is found to be in excellent agreement with the experimental results. The agreement between the theory and experiments allows us to predict structural properties of the PolyIL films. We have observed significant softening of the PolyIL films beyond certain threshold voltages and formation of holes under a scanning probe microscopy (SPM) tip, through which an electric field was applied. The observed softening is explained by the theory of depression in glass transition temperature resulting from enhanced dissociation of ions with an increase in applied electric field.Polymerized ionic liquids (PolyILs) are promising materials for various solid state electronic applications such as dye-sensitized solar cells, lithium batteries, actuators, field-effect transistors, light emitting electrochemical cells, and electrochromic devices. However, fundamental understanding of interconnection between ionic transport and mechanical properties in PolyILs is far from complete. In this work, local charge transport and structural changes in films of a PolyIL are studied using an integrated experiment-theory based approach. Experimental data for the kinetics of charging and steady state current-voltage relations can be explained by taking into account the dissociation of ions under an applied electric field (known as the Wien effect). Onsager's theory of the Wien effect coupled with the Poisson-Nernst-Planck formalism for the charge transport is found to be in excellent agreement with the experimental results. The agreement between the theory and experiments allows us to predict structural properties of the PolyIL films. We have observed significant softening of the PolyIL films beyond certain threshold voltages and formation of holes under a scanning probe microscopy (SPM) tip, through which an electric field was applied. The observed softening is explained by the theory of depression in glass transition temperature resulting from enhanced dissociation of ions with an increase in applied electric field. Electronic supplementary information (ESI) available: Details of the COMSOL modeling focusing on temperature distribution in polymer film under biased AFM tip, estimated of ionic conductivity using SPM and BDS measurements, Poisson-Nernst-Planck-Wien-Onsager model and thermodynamic description of the depression in melting due to the presence of ``free'' ions can be found in the ESI. See DOI: 10.1039/c4nr05491a

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

    Microsoft Academic Search

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

    2009-01-01

    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

  4. Alkylammonium Formate Ionic Liquids as Organic Mobile Phase Replacements for Reversed?Phase Liquid Chromatography

    Microsoft Academic Search

    Martin M. Waichigo; Brian M. Hunter; Thomas L. Riechel; Neil D. Danielson

    2007-01-01

    Alkylammonium formate (AAF) ionic liquids, RNH3 [HCO2 ], R=C2H5, C3H7, or C4H9, are prepared in high yield and purity by slowly reacting an alkylamine and formic acid in an ice bath under N2. UV spectra of undiluted ethylammonium formate (EAF), n?propylammonium formate (PAF), n?butylammonium formate (BAF) show no appreciable background absorbance down to about 250 nm, 270 nm, and 295 nm, respectively. Physical

  5. Why Are Ionic Liquids Liquid? A Simple Explanation Based on Lattice and Solvation Energies

    Microsoft Academic Search

    Ingo Krossing; John M. Slattery; Corinne Daguenet; Paul J. Dyson; Alla Oleinikova; Hermann Weingartner

    2006-01-01

    We have developed a simple and quantitative explanation for the relatively low melting temperatures of ionic liquids (ILs). The basic concept was to assess the Gibbs free energy of fusion (¢fusG) for the process IL(s) f IL(l), which relates to the melting point of the IL. This was done using a suitable Born-Fajans-Haber cycle that was closed by the lattice

  6. Effect of ionic liquids on (vapor + liquid) equilibrium behavior of (water + 2-methyl-2-propanol)

    Microsoft Academic Search

    Lianzhong Zhang; Bingbang Qiao; Yun Ge; Dongshun Deng; Jianbing Ji

    2009-01-01

    Isobaric T, x, y data were reported for ternary systems of {water+2-methyl-2-propanol (tert-butyl alcohol, TBA)+ionic liquid (IL)} at p=100kPa. When the mole fraction of TBA on IL-free basis was fixed at 0.95, measurements were performed at IL mass fractions from 0.6 down to 0.05, in a way of repeated synthesis. The vapor-phase compositions were obtained by analytical methods and the

  7. Diffusion of organic dyes in ionic liquid and giant micron sized ionic liquid mixed micelle: fluorescence correlation spectroscopy.

    PubMed

    Sasmal, Dibyendu Kumar; Mandal, Amit Kumar; Mondal, Tridib; Bhattacharyya, Kankan

    2011-06-23

    Diffusion of organic dyes in neat room temperature ionic liquid (RTIL) and RTIL-mixed micelle has been studied by fluorescence correlation spectroscopy (FCS). We have selected two RTILs, 3-pentyl-1-methyl imidazolium bromide ([C5C1Im][Br]) and the corresponding tetra-fluoroborate ([C5C1Im][BF(4)]). Diffusion coefficients (D(t)) of three organic dyes--DCM (neutral), C480 (neutral), and C343 (anionic)--in these RTILs are ?100 times slower compared to water. This indicates very high viscosity of the RTILs. In contrast to water, the D(t) in RTIL exhibits a wide distribution which suggests the presence of heterogeneity (nanoscale organization). The presence of ions in the RTILs markedly affects diffusion in the RTILs. D(t)'s of C480 (neutral) and C343 (anionic) are very similar in water but in RTILs the ionic dye C343 diffuses 1.7 times slower than neutral C480. This is attributed to the electrostatic force exerted by the ions in the RTILs. In the giant (?2-4 ?m) [C5C1Im][Br]-triblock copolymer (P123) mixed micelle D(t) of DCM, C480, and C343 are found to be 7, 15, and 7 ?m(2) s(-1), respectively. The results are compared with those in P123 micelle and gel. PMID:21619001

  8. Pretreatment of lignocellulosic biomass with renewable cholinium ionic liquids: Biomass fractionation, enzymatic digestion and ionic liquid reuse.

    PubMed

    An, Yan-Xia; Zong, Min-Hua; Wu, Hong; Li, Ning

    2015-09-01

    Pretreatment of lignocelluloses is a key step in the biorefinery for production of biofuels and valuable platform chemicals. In this work, various lignocelluloses were pretreated using cholinium ionic liquids (ILs) that are wholly composed of biomaterials, and fractionated into carbohydrate-rich materials (CRMs) and lignin-rich materials (LRMs). Cholinium ILs were found to be effective pretreatment solvents for grass lignocelluloses as well as eucalyptus, resulting in significant improvements in the glucose yields (58-75%) in subsequent enzymatic hydrolysis, while they were inefficient to make pine susceptible to biodegradation. Approximately 46% of lignin in native rice straw was fractionated as LRM after pretreatment using cholinium argininate ([Ch][Arg]). [Ch][Arg] showed excellent recyclability, and the total recovery was as high as 75% after reused for 8 cycles. Besides, rice straw pretreated by the recycled IL remained highly digestible, and good glucose yields (63-75%) were achieved after its enzymatic hydrolysis. PMID:26026293

  9. Absorption degree analysis on biogas separation with ionic liquid systems.

    PubMed

    Zhang, Xin; Zhang, Suojiang; Bao, Di; Huang, Ying; Zhang, Xiangping

    2014-10-22

    For biogas upgrading, present work mainly focuses on either thermodynamics or mass transfer properties. A systematical study on these two aspects is important for developing a new biogas separation process. In this work, a new criterion "absorption degree", which combines both thermodynamics and mass transfer properties, was proposed for the first time to comprehensively evaluate the absorption performance. Henry's law constants of CO2 and CH4 in ionic liquids-polyethylene glycol dimethyl ethers mixtures were investigated. The liquid-side mass transfer coefficients (kL) were determined. The results indicate that IL-NHD mixtures exhibit not only a high CO2/CH4 selectivity, but also a fast kL for CO2 absorption. The [bmim][NO3]+NHD mixtures present a high absorption degree value for CO2 but a low value for CH4. For presenting a highest relative absorption degree value, the 50wt% [bmim][NO3]+50wt% NHD mixture is recommended for biogas upgrading. PMID:25459814

  10. Irreversible structural change of a dry ionic liquid under nanoconfinement.

    PubMed

    Jurado, L Andres; Kim, Hojun; Arcifa, Andrea; Rossi, Antonella; Leal, Cecilia; Spencer, Nicholas D; Espinosa-Marzal, Rosa M

    2015-05-13

    Studies of 1-hexyl-3-methyl-imidazolium ethylsulfate ([HMIM] EtSO4) using an extended surface forces apparatus show, for the first time, an ordered structure within the nanoconfined ionic liquid (IL) between mica surfaces that extends up to ?60 nm from the surface. Our measurements show the growth of this ordered IL-film upon successive nanoconfinements-the structural changes being irreversible upon removal of the confinement-and the response of the structure to shear. The compressibility of this system is lower than that typically measured for ILs, while creep takes place during shear, both findings supporting a long-range liquid-to-solid transition. AFM (sharp-tip) studies of [HMIM] EtSO4 on mica only reveal ?2 surface IL-layers, with order extending only ?3 nm from the surface, indicating that confinement is required for the long-range IL-solidification to occur. WAXS studies of the bulk IL show a more pronounced ordered structure than is the case for [HMIM] with bis(trifluoromethylsulfonyl)imide as anion, but no long-range order is detected, consistent with the results obtained with the sharp AFM tip. These are the first force measurements of nanoconfinement-induced long-range solidification of an IL. PMID:25941682

  11. Thermoelectric energy recovery at ionic-liquid/electrode interface

    E-print Network

    Marco Bonetti; Sawako Nakamae; Bo Tao Huang; Thomas J. Salez; Cecile Wiertel-Gasquet; Michel Roger

    2015-06-22

    A Thermally Chargeable Capacitor containing a binary solution of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)-imide (EMIMTFSI) in acetonitrile is electrically charged by applying a tempera- ture gradient to two ideally polarisable electrodes. The corresponding thermoelectric coefficient is -1.7 mV/K for platinum foil electrodes and -0.3 mV/K for nanoporous carbon electrodes. Stored electrical energy is extracted by discharging the capacitor through a resistor. The measured capacitance of the electrode/ionic- liquid interface is 5 micro $\\mu$F for each platinum electrode while it becomes four orders of magnitude larger $\\approx 36$ mF for a single nanoporous carbon electrode. Reproducibility of the effect through repeated charging-discharging cycles under a steady-state temperature gradient demonstrates the robustness of the electrical charging pro- cess at the liquid/electrode interface. The acceleration of the charging by convective flows is also observed. This offers the possibility to convert waste-heat into electric energy without exchanging electrons between ions and electrodes, in contrast to what occurs in most thermogalvanic cells.

  12. Thermoelectric energy recovery at ionic-liquid/electrode interface.

    PubMed

    Bonetti, Marco; Nakamae, Sawako; Huang, Bo Tao; Salez, Thomas J; Wiertel-Gasquet, Cécile; Roger, Michel

    2015-06-28

    A thermally chargeable capacitor containing a binary solution of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)-imide in acetonitrile is electrically charged by applying a temperature gradient to two ideally polarisable electrodes. The corresponding thermoelectric coefficient is -1.7 mV/K for platinum foil electrodes and -0.3 mV/K for nanoporous carbon electrodes. Stored electrical energy is extracted by discharging the capacitor through a resistor. The measured capacitance of the electrode/ionic-liquid interface is 5 ?F for each platinum electrode while it becomes four orders of magnitude larger, ?36 mF, for a single nanoporous carbon electrode. Reproducibility of the effect through repeated charging-discharging cycles under a steady-state temperature gradient demonstrates the robustness of the electrical charging process at the liquid/electrode interface. The acceleration of the charging by convective flows is also observed. This offers the possibility to convert waste-heat into electric energy without exchanging electrons between ions and electrodes, in contrast to what occurs in most thermogalvanic cells. PMID:26133450

  13. Polymer Crystallization-Driven Gelation of an Ionic Liquid

    NASA Astrophysics Data System (ADS)

    Hoagland, David; Harner, John

    2008-03-01

    Polyethylene glycol dissolves in the room temperature ionic liquid 1-ethyl-3-methylimidiazolium ethyl sulfate [EMIM][EtSO4] when heated above about 60C, the neat polymer's melting temperature. At typical polymer molecular weight and concentration, the homogeneous, slightly viscous solution solidifies during subsequent cooling, forming a semitransparent gel. For example, a 5 wt. percent solution of 6000 MW polymer produces a gel with modulus exceeding 1 KPa at 45C; cooled further to room temperature, the gel's modulus rises to a temperature-insensitive plateau of over 100 KPa. By DSC, rheology, and optical microscopy, gelation of the liquid is traced to kinetically frustrated polymer crystallization, a phenomenon previously reported for many pairings of crystallizable polymer and traditional solvent. Polarized optical microscopy reveals nucleation and growth of fibrillar polymer crystals during cooling, and these crystals, here with largest dimenions of tens to hundreds of microns, act as junction points. Melting is at a temperature higher than for gelation. Surprisingly, gelation can occur even when the starting polymer concentration is an order of magnitude below coil overlap. [EMIM][EtSO4] is hygroscopic, and with water uptake, the modulus drops.

  14. 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. PMID:24188074

  15. Ionic liquid-modified metal sulfides/graphene oxide nanocomposites for photoelectric conversion

    NASA Astrophysics Data System (ADS)

    Zhang, Yu; Zhang, Yù; Pei, Qi; Feng, Ting; Mao, Hui; Zhang, Wei; Wu, Shuyao; Liu, Daliang; Wang, Hongyu; Song, Xi-Ming

    2015-08-01

    Ionic liquid-modified metal sulfides/graphene oxide nanocomposites are prepared via a facile electrostatic adsorption. Ionic liquid (IL) is firstly used as surface modifier and structure-directing agent of metal sulfide (MS) crystallization process, obtaining ionic liquid modified-MS (IL-MS) nanoparticles with positive charges on surface. IL-MS/GO is obtained by electrostatic adherence between positively charged IL-MS and negatively charged graphene oxide (GO). The as-prepared sample shows enhanced photocurrent and highly efficient photocatalytic activity under visible light irradiation, indicating IL-MS/GO nanocomposites greatly promoted the separation of photogenerated electron-hole pairs.

  16. Film Thickness of Ionic Liquids Under High Contact Pressures as a Function of Alkyl Chain Length

    Microsoft Academic Search

    Huaping XiaoDan; Dan Guo; Shuhai Liu; Guoshun Pan; Xinchun Lu

    2011-01-01

    Ionic liquids are generally considered as environmentally friendly material. The film thicknesses of ionic liquids and silicone\\u000a oils at high pressures up to 3 GPa are measured employing the relative optical interference intensity method. The results\\u000a show that for the three ionic liquids the relative order of film thickness is 1-octyl-3-methylimidazolium hexafluorophosphate\\u000a ([OMIM]PF6) > 1-hexyl-3-methylimidazolium hexafluorophosphate ([HMIM]PF6) > 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM]PF6). In elastohydrodynamic lubrication the

  17. Ionic liquids supported on metal-organic frameworks: remarkable adsorbents for adsorptive desulfurization.

    PubMed

    Khan, Nazmul Abedin; Hasan, Zubair; Jhung, Sung Hwa

    2014-01-01

    Acidic ionic-liquids (IL) supported on metal-organic frameworks (MOFs) have been shown to be beneficial for adsorptive desulfurization. A remarkable improvement in the adsorption capacity (ca. 71%) was observed in for ILs supported on MIL-101 compared with virgin MIL-101. The improved adsorptive performance might be explained by the acid-base interactions between the acidic ionic liquid and basic benzothiophene (BT). Moreover, from this study, it can be suggested that porous MOFs, supported with ionic liquids, may introduce a new class of highly porous adsorbents for the efficient adsorption of various compounds. PMID:24390909

  18. Microwave-Assisted Resolution of ?-Lipoic Acid Catalyzed by an Ionic Liquid Co-Lyophilized Lipase.

    PubMed

    Liu, Ning; Wang, Lei; Wang, Zhi; Jiang, Liyan; Wu, Zhuofu; Yue, Hong; Xie, Xiaona

    2015-01-01

    The combination of the ionic liquid co-lyophilized lipase and microwave irradiation was used to improve enzyme performance in enantioselective esterification of ?-lipoic acid. Effects of various reaction conditions on enzyme activity and enantioselectivity were investigated. Under optimal condition, the highest enantioselectivity (E = 41.2) was observed with a high enzyme activity (178.1 ?mol/h/mg) when using the ionic liquid co-lyophilized lipase with microwave assistance. Furthermore, the ionic liquid co-lyophilized lipase exhibited excellent reusability under low power microwave. PMID:26035096

  19. Synthesis and Applications of Ionic Liquids Derived from Natural Sugars

    NASA Astrophysics Data System (ADS)

    Chiappe, Cinzia; Marra, Alberto; Mele, Andrea

    Aiming to develop environmentally compatible chemical syntheses, the replacement of traditional organic solvents with ionic liquids (ILs) has attracted considerable attention. ILs are special molten salts with melting points below 100°C that are typically constituted of organic cations (imidazolium, pyridinium, sulfonium, phosphonium, etc.) and inorganic anions. Due to their ionic nature, they are endowed with high chemical and thermal stability, good solvent properties, and non-measurable vapor pressure. Although the recovery of unaltered ILs and recycling partly compensate their rather high cost, it is important to develop new synthetic approaches to less expensive and environmentally sustainable ILs based on renewable raw materials. In fact, most of these alternative solvents are still prepared starting from fossil feedstocks. Until now, only a limited number of ILs have been prepared from renewable sources. Surprisingly, the most available and inexpensive raw material, i.e., carbohydrates, has been hardly exploited in the synthesis of ILs. In 2003 imidazolium-based ILs were prepared from d-fructose and used as solvents in Mizoroki-Heck and Diels-Alder reactions. Later on, the first chiral ILs derived from sugars were prepared from methyl d-glucopyranoside. In the same year, a family of new chiral ILs, obtained from commercial isosorbide (dianhydro-d-glucitol), was described. A closely related approach was followed by other researchers to synthesize mono- and bis-ammonium ILs from isomannide (dianhydro-d-mannitol). Finally, a few ILs bearing a pentofuranose unit as the chiral moiety were prepared using sugar phosphates as glycosyl donors and 1-methylimidazole as the acceptor.

  20. Ionic Liquid Development for Absorption Heat Pump Applications

    SciTech Connect

    MAERZKE, Katie [University of Notre Dame, IN; MOZURKEWICH, George [Ionic Research Technologies LLC; Abdelaziz, Omar [ORNL; Gluesenkamp, Kyle R [ORNL; Schneider, William F [University of Notre Dame, IN; Morrison, Doug [Ionic Research Technologies LLC; Maginn, Prof. Edward [University of Notre Dame, IN

    2014-01-01

    Ionic liquids (ILs) are a unique class of solvents with many potential applications, including absorption heating/cooling. Due to the large number of possible combinations of cations and anions, it is possible to tune the IL to obtain the required properties for the application of interest. Many ILs are very hydrophilic, while even the most hydrophobic ILs often absorb significant amounts of water. The presence of water in an IL can have a large effect on the system properties. For instance, a small amount of dissolved water often leads to a dramatic reduction in the viscosity of the mixture. Dissolved water also affects the ionic conductivity of ILs and alters the solvation power of ILs for both polar and non-polar solutes. Knowledge of the phase diagram of these IL/water mixtures therefore is essential when designing absorption heating systems. Measuring isotherms often requires time consuming and/or expensive experiments, and does not necessarily lead to a deeper understanding of the molecular level interactions responsible for water-IL interactions. In contrast, molecular simulations are relatively inexpensive to perform, allowing one to screen potential ILs for a given application. Simulation also provides a detailed picture of how water and a given IL interact, thereby providing insight into ways of designing an IL to have a desired water solubility. Toward this end, atomistic-level Monte Carlo (MC) simulations have been performed to predict isotherms for a variety of IL/water mixtures. The simulations predict that exchanging some of the IL cations with a small metal cation can lead to an increase in the hydrophilicity of the IL, which impacts the capacity of the fluid and the enthalpy of mixing. Molecular dynamics simulations, which unlike Monte Carlo simulations capture timedependent properties, were also carried out to estimate the relative viscosities of the solutions.

  1. Li Ion Conducting Polymer Gel Electrolytes Based on Ionic Liquid/PVDF-HFP Blends

    PubMed Central

    Ye, Hui; Huang, Jian; Xu, Jun John; Khalfan, Amish; Greenbaum, Steve G.

    2009-01-01

    Ionic liquids thermodynamically compatible with Li metal are very promising for applications to rechargeable lithium batteries. 1-methyl-3-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide (P13TFSI) is screened out as a particularly promising ionic liquid in this study. Dimensionally stable, elastic, flexible, nonvolatile polymer gel electrolytes (PGEs) with high electrochemical stabilities, high ionic conductivities and other desirable properties have been synthesized by dissolving Li imide salt (LiTFSI) in P13TFSI ionic liquid and then mixing the electrolyte solution with poly(vinylidene-co-hexafluoropropylene) (PVDF-HFP) copolymer. Adding small amounts of ethylene carbonate to the polymer gel electrolytes dramatically improves the ionic conductivity, net Li ion transport concentration, and Li ion transport kinetics of these electrolytes. They are thus favorable and offer good prospects in the application to rechargeable Li batteries including open systems like Li/air batteries, as well as more “conventional” rechargeable lithium and lithium ion batteries. PMID:20354587

  2. Determination of Estrogens in Water Samples by Ionic Liquid-Based Dispersive Liquid-Liquid Microextraction Combined with High Performance Liquid Chromatography

    Microsoft Academic Search

    Cui-Qin Wu; Di-Yun Chen; Yin-Si Feng; Hong-Mei Deng; Yong-Hui Liu; Ai-Ju Zhou

    2012-01-01

    Using 1-hexyl-3-methylimidazolium hexafluorophosphate ([C6MIM][PF6]) ionic liquid as extraction solvent, five estrogens including estrone (E1), 17?-estradiol (E2), estriol (E3), 17? -ethynylestradiol (EE2), and diethylstilbestrol (DES) in water samples were determined by dispersive liquid-liquid microextraction (DLLME) followed by high performance liquid chromatography with a photodiode array detector and a fluorescence detector (HPLC-DAD-FLD). The extraction procedure was induced by the formation of cloudy

  3. Improved Turn-on Times of Iridium Electroluminescent Devices by Use of Ionic Liquids

    E-print Network

    Bernhard, Stefan

    Improved Turn-on Times of Iridium Electroluminescent Devices by Use of Ionic Liquids Sara T. ParkerVised Manuscript ReceiVed April 13, 2005 We demonstrate an improvement in the turn-on time of electroluminescent Electroluminescent devices based on ionic transition metal complexes (iTMCs) are being extensively studied

  4. Extraction of Biofuels and Biofeedstocks from Aqueous Solutions Using Ionic Liquids

    E-print Network

    Stadtherr, Mark A.

    Extraction of Biofuels and Biofeedstocks from Aqueous Solutions Using Ionic Liquids Luke D. Simoni-Butanol, Extraction, Liquid-Liquid Equilibrium, Excess Gibbs Energy Models, Biofuels #12;1 1. Introduction other organic compounds can be produced biologically, and thus can be considered as biofuel candidates

  5. Bilayer membrane permeability of ionic liquid-filled block copolymer vesicles in aqueous solution.

    PubMed

    Bai, Zhifeng; Zhao, Bin; Lodge, Timothy P

    2012-07-19

    The bilayer membrane permeability of block copolymer vesicles ("polymersomes") with ionic liquid interiors dispersed in water is quantified using fluorescence quenching. Poly((1,2-butadiene)-b-ethylene oxide) (PB-PEO) block copolymer vesicles in water with their interiors filled with a common hydrophobic ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide, were prepared containing a hydrophobic dye, Nile Red, by intact migration of dye-encapsulated vesicles from the ionic liquid to water at room temperature. A small quencher molecule, dichloroacetamide, was added to the aqueous solution of the dye-loaded vesicles, and the permeation of the quencher passing through the membrane into the interior was determined from the fluorescence quenching kinetics. Rapid permeation of the quencher across the nanoscale membrane was observed, consistent with the high fluidity of the liquid polybutadiene membrane. Two different PB-PEO copolymers were employed, in order to vary the thickness of the solvophobic membrane. A significant increase in membrane permeability was also observed with decreasing membrane thickness, which is tentatively attributable to differences in quencher solubility in the membranes. Quantitative migration of the vesicles from the aqueous phase back to an ionic liquid phase was achieved upon heating. These microscopically heterogeneous and thermoresponsive vesicles with permeable and robust membranes have potential as recyclable nanoreactors, in which the high viscosity and capital expense of an ionic liquid reaction medium can be mitigated, while retaining the desirable features of ionic liquids as reaction media, and facile catalyst recovery. PMID:22765509

  6. Effect of protic ionic liquid and surfactant structure on partitioning of polyoxyethylene non-ionic surfactants.

    PubMed

    Topolnicki, Inga L; FitzGerald, Paul A; Atkin, Rob; Warr, Gregory G

    2014-08-25

    The partitioning constants and Gibbs free energies of transfer of poly(oxyethylene) n-alkyl ethers between dodecane and the protic ionic liquids (ILs) ethylammonium nitrate (EAN) and propylammonium nitrate (PAN) are determined. EAN and PAN have a sponge-like nanostructure that consists of interpenetrating charged and apolar domains. This study reveals that the ILs solvate the hydrophobic and hydrophilic parts of the amphiphiles differently. The ethoxy groups are dissolved in the polar region of both ILs by means of hydrogen bonds. The environment is remarkably water-like and, as in water, the solubility of the ethoxy groups in EAN decreases on warming, which underscores the critical role of the IL hydrogen-bond network for solubility. In contrast, amphiphile alkyl chains are not preferentially solvated by the charged or uncharged regions of the ILs. Rather, they experience an average IL composition and, as a result, partitioning from dodecane into the IL increases as the cation alkyl chain is lengthened from ethyl to propyl, because the IL apolar volume fraction increases. Together, these results show that surfactant dissolution in ILs is related to structural compatibility between the head or tail group and the IL nanostructure. Thus, these partitioning studies reveal parameters for the effective molecular design of surfactants in ILs. PMID:24862589

  7. Morphology and Ionic Conductivity of Block Copolymer Electrolytes Containing Ionic Liquids

    NASA Astrophysics Data System (ADS)

    Park, Moon Jeong

    2015-03-01

    The global energy crisis and an increase in environmental pollution in the recent years have drawn the attention of the scientific community towards the development of efficient electrochemical devices. Polymers containing charged species have the potential to serve as electrolytes in next-generation devices and achieving high ion transport properties in these electrolytes is the key to improving their efficiency. Although the synthesis and characterization of a wide variety of ion-containing polymers have been extensively reported over the last decade, quantitative understanding of the factors governing the ion transport properties of these materials is in its infancy. In this talk, I will present the current understanding of the diverse factors affecting the thermodynamics, morphologies and ion transport of ion-containing polymers by focusing on the use of ionic liquids (ILs). Various strategies for accessing improved transport properties of IL-containing polymers are elucidated by focusing on the role of IL-polymer interactions. The major accomplishment of obtaining well-defined morphologies for these IL-containing polymers by the use of block copolymer is particularly emphasized as a novel means of controlling the transport properties. The application of IL-incorporated polymer electrolytes in high temperature fuel cells and electro-active actuators is also enclosed.

  8. Orientational dynamics of the ionic organic liquid 1-ethyl-3-methylimidazolium nitrate

    E-print Network

    Fayer, Michael D.

    Orientational dynamics of the ionic organic liquid 1-ethyl-3-methylimidazolium nitrate Hu Cang, Jie-methylimidazolium nitrate (EMIM NO3 ) over time scales from 1 ps to 2 ns, and the temperatures range from 410 to 295

  9. Composite Electrolytes for Lithium Batteries: Ionic Liquids in APTES Crosslinked Polymers

    NASA Technical Reports Server (NTRS)

    Tigelaar, Dean M.; Meador, Mary Ann B.; Bennett, William R.

    2007-01-01

    Solvent free polymer electrolytes were made consisting of Li(+) and pyrrolidinium salts of trifluoromethanesulfonimide added to a series of hyperbranched poly(ethylene oxide)s (PEO). The polymers were connected by triazine linkages and crosslinked by a sol-gel process to provide mechanical strength. The connecting PEO groups were varied to help understand the effects of polymer structure on electrolyte conductivity in the presence of ionic liquids. Polymers were also made that contain poly(dimethylsiloxane) groups, which provide increased flexibility without interacting with lithium ions. When large amounts of ionic liquid are added, there is little dependence of conductivity on the polymer structure. However, when smaller amounts of ionic liquid are added, the inherent conductivity of the polymer becomes a factor. These electrolytes are more conductive than those made with high molecular weight PEO imbibed with ionic liquids at ambient temperatures, due to the amorphous nature of the polymer.

  10. NMR study of ion dynamics and charge storage in ionic liquid supercapacitors

    E-print Network

    Forse, Alexander C.; Griffin, John M.; Merlet, Celine; Bayley, Paul M.; Wang, Hao; Simon, Patrice; Grey, Clare P.

    2015-05-14

    Ionic liquids are emerging as promising new electrolytes for supercapacitors. While their higher operating voltages allow the storage of more energy than organic electrolytes, they cannot currently compete in terms of power performance. More...

  11. Critical cellulase and hemicellulase activities for hydrolysis of ionic liquid pretreated biomass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Critical cellulase and hemicellulase activities are identified for hydrolysis of ionic liquid (IL) pretreated poplar and switchgrass; hemicellulase rich substrates with amorphous cellulose. Enzymes from Aspergillus nidulans were expressed and purified: an endoglucanase (EG) a cellobiohydrolase (CBH)...

  12. Electrochemical Windows of Room-Temperature Ionic Liquids from Molecular Dynamics and Density Functional Theory Calculations

    E-print Network

    Ong, Shyue Ping

    We investigated the cathodic and anodic limits of six room-temperature ionic liquids (ILs) formed from a combination of two common cations, 1-butyl-3-methylimidazolium (BMIM) and N,N-propylmethylpyrrolidinium (P13), and ...

  13. Theoretical Investigations on Nanoporpus Materials and Ionic Liquids for Energy Storage 

    E-print Network

    Mani Biswas, Mousumi

    2012-02-14

    by adsorption. In this regard carbon nanotube and Metal Organic Framework (MOFs) based materials are worth studying. Ionic liquids (IL) are potential electrolytes that can improve energy storage capacity and safety in Li ion batteries. Therefore it is important...

  14. Chemoselective Esterification of Phenolic Acids in the Presence of Sodium Bicarbonate in Ionic Liquids

    Microsoft Academic Search

    Ambika; Pradeep Pratap Singh; S. M. S. Chauhan

    2008-01-01

    Chemoselective esterification of phenolic acids with dialkyl sulphates or alkyl halides in the presence of sodium bicarbonate in 1,3?dialkylimidazolium ionic liquids is reported in excellent yields and less reaction time as compared to organic solvents.

  15. First volatility study of the 1-alkylpyridinium based ionic liquids by Knudsen effusion

    NASA Astrophysics Data System (ADS)

    Rocha, Marisa A. A.; Santos, Luís M. N. B. F.

    2013-10-01

    For the first time, a volatility study of the 1-ethylpyridinium bis(trifluoromethylsulfonyl)imide ([C2Py][NTf2], CAS: 712354-97-7), 1-propylpyridinium bis(trifluoromethylsulfonyl)imide ([C3Py][NTf2]) and 1-butylpyridinium bis(trifluoromethylsulfonyl)imide ([C4Py][NTf2], CAS: 187863-42-9) ionic liquids, is presented. The vapor pressures as a function of temperature, for this ionic liquids were measured and the thermodynamic properties of vaporization were derived. The analysis and rationalization of the obtained results for the alkylpyridinium based ionic liquids was done based on the comparison with the [CN-1C1im][NTf2] (N = 3-5). The volatility of pyridinium is five times lower than the imidazolium based ionic liquids and that is driven by their higher enthalpy of vaporization.

  16. A Microfabricated Planar Electrospray Array Ionic Liquid Ion Source With Integrated Extractor

    E-print Network

    Gassend, Blaise

    This paper reports the design, fabrication, and experimental characterization of a fully microfabricated planar array of externally fed electrospray emitters that produces heavy molecular ions from the ionic liquids ...

  17. DESIGN AND EVALUATION OF IONIC LIQUIDS AS NOVEL CO2 ABSORBENTS

    SciTech Connect

    Edward J. Maginn

    2004-12-31

    Progress from the first quarter of 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: ''assembling equipment and a research team, compound synthesis and molecular modeling''. Nine new ionic liquid compounds have been made or acquired, and are in line for physical property testing to assess their potential for CO{sub 2} sequestration. Quantum mechanical calculations between CO{sub 2} and different ionic liquids have been conducted. The simulations have shed light on the nature of interactions between CO{sub 2} and the ionic liquids, and are providing insight that will be used to suggest new compounds to be synthesized and tested.

  18. In vitro cytotoxicities of ionic liquids: effect of cation rings, functional groups, and anions.

    PubMed

    Kumar, R Anand; Papaïconomou, Nicolas; Lee, Jong-Min; Salminen, Justin; Clark, Douglas S; Prausnitz, John M

    2009-08-01

    In vitro cytotoxicities were measured for ionic liquids (ILs) containing various cations and anions using the MCF7 human breast cancer cell line. We measured the cytotoxicities of ionic liquids containing the cations pyridinium, pyrrolidinium, piperidinium, or imidazolium with various alkyl chain lengths, and the anions bromide, bis(trifluoromethanesulfone)imide (Tf(2)N), trifluoromethylsulfonate (TfO), or nonafluoromethylsulfonate (NfO). Three new hydrophobic, task-specific ionic liquids (TSILs), namely, [MBCNPip](+)[Tf(2)N](-), [MPS(2)Pip](+)[Tf(2)N](-), and [MPS(2)Pyrro](+)[Tf(2)N](-) designed for metal-ion extraction were also evaluated. IC(50) values of the ionic liquids toward the MCF7 cells ranged from 8 microM to 44 mM. The toxicity depended significantly on the nature of the cations and anions, especially when the cations contained a long side chain. TSILs studied in this work were less toxic than the classical ILs. PMID:18825729

  19. Higher energy and safety of lithium-ion batteries with ionic liquid electrolyte

    NASA Astrophysics Data System (ADS)

    Komaba, Shinichi; Yabuuchi, Naoaki; Katayama, Yasushi; Miura, Takashi

    2010-04-01

    Ionic liquid has been utilized as safe electrolyte solution for lithium-ion batteries. Reversible charge / discharge cycling of the graphite electrode in the ionic liquid has been achieved with polyacrylic acid polymer binder, which can suppress the organic cation intercalation to the graphite. Cycleability of the graphite-silicon composite electrodes prepared with polyacrylate binder was significantly improved in comparison to the conventional PVdF binder, and it has been demonstrated that the reversible cycling with 1000 mAh g-1 for 30 cycling test is possible in ionic liquid. The possibility of the safe and high-energy lithium-ion battery is discussed through the preliminary study on Li2MnO3-LiCo1/3Ni1/3Mn1/3O2 based positive electrode and graphite-silicon-polyacrylate composite negative electrode with the ionic liquid electrolyte.

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

    PubMed

    Bendaoud, Amine; Chalamet, Yvan

    2014-08-01

    Cellulose acetate (CA) plasticized by 1-butyl-3-methylimidazolium chloride (BMIMCl) and with diethylphtalate (DEP) was obtained by melt processing at 150°C. The effect and the interaction of ionic liquid with the cellulose acetate and their influence on structural, thermo-mechanical, rheological and tensile properties of CA materials were investigated. Ionic liquid (BMIMCl) has shown a good plasticization and more efficient destruction of the crystalline structure of cellulose acetate than the DEP plasticized CA. BMIMCl interacts intensively with CA molecules due to the pronounced van der Waals interactions, hydrogen bonding and electrostatic nature of ionic liquid. The tensile test and the low Young's modulus for plasticized CA suggest a strong reduction of the interaction between the CA chains due to the presence of the ionic liquid. PMID:24751249

  1. Determination of preservatives in soft drinks by capillary electrophoresis with ionic liquids as the electrolyte additives.

    PubMed

    Sun, Bingbing; Qi, Li; Wang, Minglin

    2014-08-01

    A capillary electrophoresis method for separating preservatives with various ionic liquids as the electrolyte additives has been developed. The performances for separation of the preservatives using five ionic liquids with different anions and different substituted group numbers on imidazole ring were studied. After investigating the influence of the key parameters on the separation (the concentration of ionic liquids, pH, and the concentration of borax), it has been found that the separation efficiency could be improved obviously using the ionic liquids as the electrolyte additives and tested preservatives were baseline separated. The proposed capillary electrophoresis method exhibited favorable quantitative analysis property of the preservatives with good linearity (r(2) = 0.998), repeatability (relative standard deviations ? 3.3%) and high recovery (79.4-117.5%). Furthermore, this feasible and efficient capillary electrophoresis method was applied in detecting the preservatives in soft drinks, introducing a new way for assaying the preservatives in food products. PMID:24910409

  2. Communication: Unusual structure and transport in ionic liquid-hexane mixtures

    DOE PAGESBeta

    Liang, Min [Rutgers Univ., Piscataway, NJ (United States). Dept. of Chemistry and Chemical Biology; Khatun, Sufia [Rutgers Univ., Piscataway, NJ (United States). Dept. of Chemistry and Chemical Biology; Castner, Edward W. [Rutgers Univ., Piscataway, NJ (United States). Dept. of Chemistry and Chemical Biology

    2015-03-28

    Ionic liquids having a sufficiently amphiphilic cation can dissolve large volume fractions of alkanes, leading to mixtures with intriguing properties on molecular length scales. The trihexyl(tetradecyl)phosphonium cation paired with the bis(trifluoromethylsulfonyl)amide anion provides an ionic liquid that can dissolve large mole fractions of hexane. We present experimental results on mixtures of n-C6D14 with this ionic liquid. High- energy X-ray scattering studies reveal a persistence of the characteristic features of ionic liquid structure even for 80% dilution with n-C6D14. NMR self-diffusion results reveal decidedly non-hydrodynamic behavior where the self-diffusion of the neutral, non-polar n-C6D14 is on average a factor of 21 times faster than for the cation. Exploitation of the unique structural and transport properties of these mixtures may lead to new opportunities for designer solvents for enhanced chemical reactivity and interface science.

  3. Physicochemical properties and toxicities of hydrophobic piperidinium and pyrrolidinium ionic liquids

    E-print Network

    2007-01-01

    thermal stability of electrolyte mixtures used in batteries.ion batteries and other electrochemical devices. Thermalthermal stability of an ionic liquid increases safety in applications like rechargeable lithium-ion batteries

  4. Extraction of S- and N-compounds from the mixture of hydrocarbons by ionic liquids as selective solvents.

    PubMed

    Gabri?, 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

  5. An ionically tagged water-soluble artificial enzyme promotes the dephosphorylation reaction with nitroimidazole: enhanced ionic liquid effect and mechanism.

    PubMed

    Ferreira, José G L; Ramos, Luciana M; de Oliveira, Aline L; Orth, Elisa S; Neto, Brenno A D

    2015-06-01

    In this paper, we describe a novel synthesized ionically tagged water-soluble artificial enzyme (PI) that can efficiently cleave phosphate esters, with enhanced an ionic liquid effect through cooperative effects for the substrate activation and further nucleophilic reaction. The dephosphorylation reaction with PI was evaluated in the presence and absence of 2-methyl-4(5)-nitroimidazole, showing impressive rate enhancements of up to 2 × 10(6)-fold, ascribed to the imidazolide species known as excellent nucleophiles, and formed favorably at lower pH values in the presence of PI. PMID:25950110

  6. Modification and implications of changes in electrochemical responses encountered when undertaking deoxygenation in ionic liquids.

    PubMed

    Zhao, Chuan; Bond, Alan M; Compton, Richard G; O'Mahony, Aoife M; Rogers, Emma I

    2010-05-01

    Physicochemical changes and substantially modified electrochemical behavior have been reported when ionic liquids are degassed with nitrogen. In conventional experiments in aqueous and organic media, degassing with N(2) is commonly used to remove the electroactive dissolved oxygen. However, in hydrophilic ionic liquid media, degassing with N(2) removes not only the dissolved oxygen but also a significant amount of the adventitious water present. Given the low viscosity of water, this in turn leads to a dramatic change of the viscosity of the degassed ionic liquid and hence mass transport properties that influence voltammetric responses. In the widely used and relatively viscous room temperature ionic liquid, 1-n-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF(4)) containing the redox probe tetracyanoquinodimethane (TCNQ) and 9% (v/v) deliberately added water, 1 h degassing with very dry N(2) under benchtop conditions results in a dramatic decrease of the TCNQ reduction current obtained under steady-state conditions at a 1 mum diameter microdisc electrode. This is reflected by a change of diffusion coefficient of TCNQ (D(TCNQ)) from 2.6 x 10(-7) to 4.6 x 10(-8) cm(2) s(-1). Karl Fischer titration measurements show that almost complete removal of the deliberately added 9% water is achieved by degassing under benchtop conditions. However, displacement of oxygen by nitrogen in the ionic liquid solution results in the decrease of electrochemical reduction current by 6%, implying that dissolved gases need not be inert with respect to solvent properties. Oxygen removal by placing the BMIMBF(4) ionic liquid in a nitrogen-filled glovebox or in a vacuum cell also simultaneously leads to removal of water and alteration of voltammetric data. This study highlights that (i) important physicochemical differences may arise upon addition or removal of a solute from viscous ionic liquids; (ii) degassing with dry nitrogen removes water as well as oxygen from ionic liquids, which may have implications on the viscosity and structure of the medium; (iii) particular caution must be exercised when deoxygenation is applied in ionic liquid media as part of the protocol used in electrochemical experiments to remove oxygen; (iv) gases such as oxygen, argon, and nitrogen dissolved in ionic liquids need not be innocent with respect to the properties of an ionic liquid. The use of vacuum based techniques to eliminate all volatile solutes, including water and oxygen, is advocated. PMID:20392069

  7. Electrochemical activity of glucose oxidase on a poly(ionic liquid) - Au nanoparticle composite.

    SciTech Connect

    Lee, S.; Ringstrand, B. S.; Stone, D. A.; Firestone, M. A. (Materials Science Division)

    2012-01-01

    Glucose oxidase (GOx) adsorbed on an ionic liquid-derived polymer containing internally organized columns of Au nanoparticles exhibits direct electron transfer and bioelectrocatalytic properties towards the oxidation of glucose. The cationic poly(ionic liquid) provides an ideal substrate for the electrostatic immobilization of GOx. The encapsulated Au nanoparticles serve to both promote the direct electron transfer with the recessed enzyme redox centers and impart electronic conduction to the composite, allowing it to function as an electrode for electrochemical detection.

  8. Electrochemical behaviors of metol on hydrophilic ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate-modified electrode

    Microsoft Academic Search

    Wei Sun; Qiang Jiang; Yan Wang; Kui Jiao

    2009-01-01

    In this paper a hydrophilic ionic liquid of 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIMBF4) was used as modifier to make a new kind of ionic liquid-modified carbon paste electrode (IL-CPE), which was further characterized by different methods including electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and scanning electron microscope (SEM). The fabricated IL-CPE showed good electrocatalytic behaviors towards the oxidation of metol with

  9. Study on Preparation Process of Lubrication from 1-Decene with Acidic Ionic Liquid Catalyst

    Microsoft Academic Search

    H. Ding; B. Y. Zhang; J. Liu

    2009-01-01

    Poly-alpha-olefin (PAO) was researched over acidic ionic liquid catalyzed the oligomerization of 1-decene. Ionic liquid used was 1-butyl-3-methyl imidazolium as a cation and aluminum chloride as an anion, which could effectively catalyze oligomerization and had a higher selectivity. The optimum process conditions for the synthesis of PAO were that the reaction temperature was 160°C, the reaction time was 3 h,

  10. Oil-Miscible and Non-Corrosive Phosphonium Ionic Liquids as Candidate Lubricant Additives

    Microsoft Academic Search

    Jun Qu; Huimin Luo; Sheng Dai; Peter Julian Blau; Bruce G Bunting; Gregory Mordukhovich; Donald Smolenski

    2012-01-01

    Ionic liquids (ILs) have been receiving considerable attention from the lubricants industry as potential friction and wear-reducing additives, but their solubility in oils is an issue. Unlike most ionic liquids that are insoluble in non-polar hydrocarbon oils, this study reports phosphonium-based ILs (PP-ILs) that are fully miscible with both mineral oil-based and synthetic lubricants. Both the cation and anion in

  11. Surface chemistry of fluorine containing ionic liquids on steel substrates at elevated temperature using Mössbauer spectroscopy

    Microsoft Academic Search

    B. S. Phillips; G. John; J. S. Zabinski

    2007-01-01

    Ionic liquids have properties that make them attractive as solvents for many chemical synthesis and catalysis reactions. Consequently,\\u000a research has focused on their application as advanced solvents. Recently, ionic liquids were shown to have promise as a lubricant\\u000a due to many of the same properties that make them useful as solvents. The focus of this paper is to study the

  12. Ionic liquids as lubricants for steel–aluminum contacts at low and elevated temperatures

    Microsoft Academic Search

    Ana-Eva Jiménez; María-Dolores Bermúdez

    2007-01-01

    Room temperature ionic liquids (ILs) are high performance fluids with a wide thermal stability range. In this work we present\\u000a the first study of ILs as lubricants under a wide range of temperature conditions (?30, 100, and 200 C). The tribological\\u000a performance of the imidazolium ionic liquids 1-hexyl, 3-methyl (L106) and 1-octyl, 3-methyl (L108) imidazolium tetrafluoroborates\\u000a have been compared with that

  13. A novel lubricant additive based on carbon nanotubes for ionic liquids

    Microsoft Academic Search

    Bo Yu; Zhilu Liu; Feng Zhou; Weimin Liu; Yongmin Liang

    2008-01-01

    Room Temperature Ionic Liquid (RTIL)\\/Multi-Walled Carbon Nanotubes (MWNTs) composite was prepared by chemical modification. The composite was analyzed by using laser Raman spectroscopy and X-ray photoelectron spectroscopy. The RTIL\\/MWNTs composite was evaluated as lubricant additive in ionic liquid due to their excellent dispersibility. Tribological performances of RTIL\\/MWNTs composite as lubricant additive were performed on a universal UMT-2MT Tribo-tester. It is

  14. The friction and wear characteristics and lubrication mechanism of imidazole phosphate ionic liquid

    Microsoft Academic Search

    Lin Zhang; DaPeng Feng; Bin Xu; XuQing Liu; WeiMin Liu

    2009-01-01

    Several imidazole phosphate ionic liquids with varying carbon chain length have been synthesized at room temperature. Corrosion\\u000a characteristics and tribological properties of these synthesized ionic liquids were studied using four-ball friction and wear\\u000a testing machine. Its lubrication mechanism was also investigated by means of electron microscopy and X-ray photoelectron spectroscopy.\\u000a The experimental results showed that no corrosion was generated when

  15. Phase equilibria of didecyldimethylammonium nitrate ionic liquid with water and organic solvents

    Microsoft Academic Search

    Urszula Doma?ska; Katarzyna ?ugowska; Juliusz Pernak

    2007-01-01

    The phase diagrams for binary mixtures of an ammonium ionic liquid, didecyldimethylammonium nitrate, [DDA][NO3], with: alcohols (propan-1-ol, butan-1-ol, octan-1-ol, and decan-1-ol): hydrocarbons (toluene, propylbenzene, hexane, and hexadecane) and with water were determined in our laboratory. The phase equilibria were measured by a dynamic method from T=220K to either the melting point of the ionic liquid, or to the boiling point

  16. Temperature dependence of some liquid lithium properties from the ionic pseudopotential 

    E-print Network

    Engel, Anthony Wells

    1977-01-01

    TEMPERATURE DEPENDENCE OF SOME LIQUID LITHIUM PROPERTIES FROM THE IONIC PSEUDOPOTENTIAL A Thesis AMTHOKY WELLS EEGEL Submmitted to the Gradnate College of Texas ASM University in partial fnlfillsent of the reqnirenent for the degree of MASTER... OF SCIEECE May 1977 Ma)or Sub)ect: Mnclear Engineering TEMPERATURE DEPENDENCE OP SOME LIQUID LITHIUM PROPERTIES PROM THE IONIC PSEUDOPOTENTIAL A Thesis by ANTHONY WELLS ENGEL Approved as to style and content by: ea o spar men em er em er May 1977...

  17. Elucidating graphene - Ionic Liquid interfacial region: a combined experimental and computational study

    SciTech Connect

    Vijayakumar, M.; Schwenzer, Birgit; Shutthanandan, V.; Hu, Jian Z.; Liu, Jun; Aksay, Ilhan A.

    2014-01-10

    The interfacial region between graphene and an imidazolium based ionic liquid is studied using spectroscopic analysis and computational modelling. This combined approach reveals that the molecular level structure of the interfacial region is significantly influenced by functional group defects on the graphene surface.The combined experimental and computational study reveals that the molecular structure at interfacial region between graphene and imidazolium based ionic liquid is defined by the hydroxyl functional groups on the graphene surface

  18. Ternary polymer electrolytes containing pyrrolidinium-based polymeric ionic liquids for lithium batteries

    Microsoft Academic Search

    G. B. Appetecchi; G.-T. Kim; M. Montanino; M. Carewska; R. Marcilla; D. Mecerreyes; I. De Meatza

    2010-01-01

    The electrochemical properties of solvent-free, ternary polymer electrolytes based on a novel poly(diallyldimethylammonium) bis(trifluoromethanesulfonyl)imide polymeric ionic liquid (PIL) as polymer host and incorporating PYR14TFSI ionic liquid and LiTFSI salt are reported. The PIL–LiTFSI–PYR14TFSI electrolyte membranes were found to be chemically stable even after prolonged storage times in contact with lithium anode and thermally stable up to 300°C. Particularly, the PIL-based

  19. Influence of oxygen functionalities on the environmental impact of imidazolium based ionic liquids

    Microsoft Academic Search

    Yun Deng; Pascale Besse-Hoggan; Martine Sancelme; Anne-Marie Delort; Pascale Husson; Margarida F. Costa Gomes

    Several physico-chemical properties relevant to determine the environmental impact of ionic liquids – aqueous solubility, octanol-water partition coefficient and diffusion coefficients in water at infinite dilution – together with toxicity and biodegradability of ionic liquids based on 1-alkyl-3-methylimidazolium cations with or without different oxygenated functional groups (hydroxyl, ester and ether) are studied in this work. The presence of oxygen groups

  20. Swelling and dissolution of cellulose. Part IV: Free floating cotton and wood fibres in ionic liquids

    Microsoft Academic Search

    Céline Cuissinat; Patrick Navard; Thomas Heinze

    2008-01-01

    The objective of this paper is to investigate if the swelling and dissolution mechanisms found for aqueous solvents are valid for non-aqueous ones. Three different ionic liquids were used and the swelling and dissolution mechanisms were investigated by optical methods. Native and enzymatically treated cellulose fibres (cotton and wood fibres) are dipped into three ionic liquids (1-N-butyl-3-methylimidazolium chloride ([C4mim]+Cl?)\\/DMSO, allylmethylimidazolium

  1. Visualization of biomass solubilization and cellulose regeneration during ionic liquid pretreatment of switchgrass

    Microsoft Academic Search

    Seema Singh; Blake A. Simmons; Kenneth P. Vogel

    2009-01-01

    Auto-fluorescent mapping of plant cell walls was used to visualize cellulose and lignin in pristine switchgrass (Panicum virgatum) stems to determine the mechanisms of biomass dissolution during ionic liquid pretreatment. The addition of ground switchgrass to the ionic liquid 1-n-ethyl-3-methylimidazolium acetate resulted in the disruption and solubilization of the plant cell wall at mild temperatures. Swelling of the plant cell

  2. Photoelectrochemistry of p-type Cu 2 O semiconductor electrode in ionic liquid

    Microsoft Academic Search

    Yasuhiro Tachibana; Ryusuke Muramoto; Hajime Matsumoto; Susumu Kuwabata

    2006-01-01

    We investigated the photoelectrochemical characteristics and photo-stability of Cu2O layered on a copper plate using a hydrophobic ionic liquid. Our findings revealed that Cu2O is stable under white light irradiation, provided water is removed from the electrolyte. Methyl viologen derivative, a well-established\\u000a electron acceptor, was introduced to the ionic liquid electrolyte, allowing the photo-induced electron transfer reaction at\\u000a the Cu2O\\/electrolyte

  3. Ionic Liquids and Cellulose: Dissolution, Chemical Modification and Preparation of New Cellulosic Materials

    PubMed Central

    Isik, Mehmet; Sardon, Haritz; Mecerreyes, David

    2014-01-01

    Due to its abundance and a wide range of beneficial physical and chemical properties, cellulose has become very popular in order to produce materials for various applications. This review summarizes the recent advances in the development of new cellulose materials and technologies using ionic liquids. Dissolution of cellulose in ionic liquids has been used to develop new processing technologies, cellulose functionalization methods and new cellulose materials including blends, composites, fibers and ion gels. PMID:25000264

  4. Influence of Imidazolium Ionic Liquids on Dehydrogenase Activity of Activated Sludge Microorganisms

    Microsoft Academic Search

    Ewa Liwarska-Bizukojc

    Imidazolium salts are one of the most often used and investigated groups of ionic liquids (ILs). The research concerning their\\u000a ecotoxicity comprised many test organisms representing different trophic levels; however, their impact on mixed cultures of\\u000a microorganisms such as activated sludge has been hardly ever investigated. Thus, in this work, the effect of imidazolium ionic\\u000a liquids on dehydrogenase activity of

  5. Study of dissolution of cellulose in ionic liquids by computer modeling

    Microsoft Academic Search

    N. P. Novoselov; E. S. Sashina; V. E. Petrenko; M. Zaborsky

    2007-01-01

    Computer modeling of the geometry and electronic structure of the solvent and its complexes with water and cellobiose allowed:\\u000a explaining the decrease in the dissolving power of an ionic liquid in the presence of water using data on the electronic structure\\u000a of the molecules; determining the overall mechanism of solvation of cellulose by ionic liquids and other organic solvents;\\u000a calculating

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

  7. Terrestrial ecotoxicity of short aliphatic protic ionic liquids.

    PubMed

    Peric, Brezana; Martí, Esther; Sierra, Jordi; Cruañas, Robert; Iglesias, Miguel; Garau, Maria Antonia

    2011-12-01

    A study of the ecotoxicity of different short aliphatic protic ionic liquids (PILs) on terrestrial organisms was conducted. Tests performed within the present study include those assessing the effects of PILs on soil microbial functions (carbon and nitrogen mineralization) and terrestrial plants. The results show that the nominal lowest-observed-adverse-effect concentration (LOAEC) values were 5,000 mg/kg (dry soil) for the plant test in two species (Lolium perenne, Allium cepa), 1,000 mg/kg (dry soil) for the plant test in one species (Raphanus sativus), and 10,000 mg/kg (dry soil) for carbon and nitrogen microbial transformation tests (all concentrations are nominal). Most of the median effective concentration values (EC50) were above 1,000 mg/kg (dry soil). Based on the obtained results, these compounds can be described as nontoxic for soil microbiota and the analyzed plants, and potentially biodegradable in soils, as can be deduced from the respirometric experiment. The toxicity rises with the increase of complexity of the PILs molecule (branch and length of aliphatic chain) among the three PILs analyzed. PMID:21935980

  8. Mesophases in nearly 2D room-temperature ionic liquids.

    PubMed

    Manini, N; Cesaratto, M; Del Pópolo, M G; Ballone, P

    2009-11-26

    Computer simulations of (i) a [C(12)mim][Tf(2)N] film of nanometric thickness squeezed at kbar pressure by a piecewise parabolic confining potential reveal a mesoscopic in-plane density and composition modulation reminiscent of mesophases seen in 3D samples of the same room-temperature ionic liquid (RTIL). Near 2D confinement, enforced by a high normal load, as well as relatively long aliphatic chains are strictly required for the mesophase formation, as confirmed by computations for two related systems made of (ii) the same [C(12)mim][Tf(2)N] adsorbed at a neutral solid surface and (iii) a shorter-chain RTIL ([C(4)mim][Tf(2)N]) trapped in the potential well of part i. No in-plane modulation is seen for ii and iii. In case ii, the optimal arrangement of charge and neutral tails is achieved by layering parallel to the surface, while, in case iii, weaker dispersion and packing interactions are unable to bring aliphatic tails together into mesoscopic islands, against overwhelming entropy and Coulomb forces. The onset of in-plane mesophases could greatly affect the properties of long-chain RTILs used as lubricants. PMID:19886615

  9. Structure, stability and behaviour of nucleic acids in ionic liquids

    PubMed Central

    Tateishi-Karimata, Hisae; Sugimoto, Naoki

    2014-01-01

    Nucleic acids have become a powerful tool in nanotechnology because of their conformational polymorphism. However, lack of a medium in which nucleic acid structures exhibit long-term stability has been a bottleneck. Ionic liquids (ILs) are potential solvents in the nanotechnology field. Hydrated ILs, such as choline dihydrogen phosphate (choline dhp) and deep eutectic solvent (DES) prepared from choline chloride and urea, are ‘green’ solvents that ensure long-term stability of biomolecules. An understanding of the behaviour of nucleic acids in hydrated ILs is necessary for developing DNA materials. We here review current knowledge about the structures and stabilities of nucleic acids in choline dhp and DES. Interestingly, in choline dhp, A–T base pairs are more stable than G–C base pairs, the reverse of the situation in buffered NaCl solution. Moreover, DNA triplex formation is markedly stabilized in hydrated ILs compared with aqueous solution. In choline dhp, the stability of Hoogsteen base pairs is comparable to that of Watson–Crick base pairs. Moreover, the parallel form of the G-quadruplex is stabilized in DES compared with aqueous solution. The behaviours of various DNA molecules in ILs detailed here should be useful for designing oligonucleotides for the development of nanomaterials and nanodevices. PMID:25013178

  10. Structure, stability and behaviour of nucleic acids in ionic liquids.

    PubMed

    Tateishi-Karimata, Hisae; Sugimoto, Naoki

    2014-08-01

    Nucleic acids have become a powerful tool in nanotechnology because of their conformational polymorphism. However, lack of a medium in which nucleic acid structures exhibit long-term stability has been a bottleneck. Ionic liquids (ILs) are potential solvents in the nanotechnology field. Hydrated ILs, such as choline dihydrogen phosphate (choline dhp) and deep eutectic solvent (DES) prepared from choline chloride and urea, are 'green' solvents that ensure long-term stability of biomolecules. An understanding of the behaviour of nucleic acids in hydrated ILs is necessary for developing DNA materials. We here review current knowledge about the structures and stabilities of nucleic acids in choline dhp and DES. Interestingly, in choline dhp, A-T base pairs are more stable than G-C base pairs, the reverse of the situation in buffered NaCl solution. Moreover, DNA triplex formation is markedly stabilized in hydrated ILs compared with aqueous solution. In choline dhp, the stability of Hoogsteen base pairs is comparable to that of Watson-Crick base pairs. Moreover, the parallel form of the G-quadruplex is stabilized in DES compared with aqueous solution. The behaviours of various DNA molecules in ILs detailed here should be useful for designing oligonucleotides for the development of nanomaterials and nanodevices. PMID:25013178

  11. EFFECTS OF GAMMA RADIATION ON ELECTROCHEMICAL PROPERTIES OF IONIC LIQUIDS

    SciTech Connect

    Visser, A; Nicholas Bridges, N; Thad Adams, T; John Mickalonis, J; Mark02 Williamson, M

    2009-04-21

    The electrochemical properties of ionic liquids (ILs) make them attractive for possible replacement of inorganic salts in high temperature molten salt electrochemical processing of nuclear fuel. To be a feasible replacement solvent, ILs need to be stable in moderate and high doses of radiation without adverse chemical and physical effects. Here, we exposed seven different ILs to a 1.2 MGy dose of gamma radiation to investigate their physical and chemical properties as they related to radiological stability. The azolium-based ILs experienced the greatest change in appearance, but these ILs were chemically more stable to gamma radiation than some of the other classes of ILs tested, due to the presence of aromatic electrons in the azolium ring. All the ILs exhibited a decrease in their conductivity and electrochemical window (at least 1.1 V), both of which could affect the utility of ILs in electrochemical processing. The concentration of the irradiation decomposition products was less than 3 mole %, with no impurities detectable using NMR techniques.

  12. Inter- and intramolecular interactions in imidazolium protic ionic liquids.

    PubMed

    Moschovi, Anastasia Maria; Dracopoulos, Vassileios; Nikolakis, Vladimiros

    2014-07-24

    The interactions of alkyl substituted imidazolium bis(trifluoromethanolsulfonyl)imide protic ionic liquids (PILs) HCnImNTf2 (n = 0-12) were studied using vibrational spectroscopy (FT-IR/ATR and FT-Raman) and differential scanning calorimetry (DSC). The effect of alkyl substituent length (n = 0-12) and temperature on the relative magnitude of the different interactions is elucidated. For short carbon alkyl chains (n < 3), the PIL structure is affected from intramolecular interaction caused from the induction effect (+I) due to the chain substituent of the imidazolium ring, while for PILs with n > 3 the van der Waals forces between the chains and ?-? interaction between neighboring imidazolium rings become important. The tendency of reducing the melting point and increasing glass transition values with the lengthening of the alkyl chain was also noticed as a result the increasing contribution of the van der Waals forces to the overall interactions. Finally, we also show that the conformational isomerism of the anion (expressed by ?Heq) is a good indicator of the relative magnitude of the interactions. When Coulombic interactions are predominant, the trans conformer is the most probable, while when other type of interactions (HB, vdW, etc.) become important the cis conformer is favored. PMID:24971830

  13. Distributed polarizability models for imidazolium-based ionic liquids.

    PubMed

    Millot, Claude; Chaumont, Alain; Engler, Etienne; Wipff, Georges

    2014-09-25

    Quantum chemical calculations are used to derive distributed polarizability models sufficiently accurate and compact to be used in classical molecular dynamics simulations of imidazolium-based room temperature ionic liquids. Two distributed polarizability models are fitted to reproduce the induction energy of three imidazolium cations (1,3-dimethyl-, 1-ethyl-3-methyl-, and 1-butyl-3-methylimidazolium) and four anions (tetrafluoroborate, hexafluorophosphate, nitrate, and thiocyanate) polarized by a point charge located successively on a grid of surrounding points. The first model includes charge-flow polarizabilities between first-neighbor atoms and isotropic dipolar polarizability on all atoms (except H), while the second model includes anisotropic dipolar polarizabilities on all atoms (except H). For the imidazolium cations, particular attention is given to the transferability of the distributed polarizability sets. The molecular polarizability and its anisotropy rebuilt by the distributed models are found to be in good agreement with the exact ab initio values for the three cations and 23 additional conformers of 1-ethyl-3-methyl-, 1-butyl-3-methyl-, 1-pentyl-3-methyl-, and 1-hexyl-3-methylimidazolium cations. PMID:25133873

  14. Virtual colorimetric sensor array: single ionic liquid for solvent discrimination.

    PubMed

    Galpothdeniya, Waduge Indika S; Regmi, Bishnu P; McCarter, Kevin S; de Rooy, Sergio L; Siraj, Noureen; Warner, Isiah M

    2015-04-21

    There is a continuing need to develop high-performance sensors for monitoring organic solvents, primarily due to the environmental impact of such compounds. In this regard, colorimetric sensors have been a subject of intense research for such applications. Herein, we report a unique virtual colorimetric sensor array based on a single ionic liquid (IL) for accurate detection and identification of similar organic solvents and mixtures of such solvents. In this study, we employ eight alcohols and seven binary mixtures of ethanol and methanol as analytes to provide a stringent test for assessing the capabilities of this array. The UV-visible spectra of alcoholic solutions of the IL used in this study show two absorption bands. Interestingly, the ratio of absorbance for these two bands is found to be extremely sensitive to alcohol polarity. A virtual sensor array is created by using four different concentrations of IL sensor, which allowed identification of these analytes with 96.4-100% accuracy. Overall, this virtual sensor array is found to be very promising for discrimination of closely related organic solvents. PMID:25822878

  15. Functionalized ionic liquids as electrolytes for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Pandian, Shanthi; Raju, S. G.; Hariharan, Krishnan S.; Kolake, Subramanya M.; Park, Da-Hye; Lee, Myung-Jin

    2015-07-01

    The design of potential and new electrochemically stable electrolytes for Li-ion batteries is an important task in the field of energy. Room temperature ionic liquids (RTILs) characterized by a wide electrochemical window (EW) are the commonly used electrolytes for Li battery applications. In this work, a novel quantum computational method is proposed to estimate the electrochemical stability of RTILs that accurately predicts the trends in EWs of ammonium based ILs and is computationally faster than the state-of-the-art methods. Subsequently, the EW of ILs with phosphonium and sulfonium cations are computed and compared against the well-established ammonium congeners. Based on the criterion of electrochemical stability defined with respect to Li, the increasing order of stability is found to be: sulfonium < ammonium < phosphonium based ILs. The effect of various substituents like butyl, phenyl and benzyl on the phosphonium and sulfonium based ILs is examined and a greater stability for the phenyl over other substituents is observed. The key factor influencing the reduction potential of the cations is inferred as the thermodynamic stability of the radical formed during decomposition. Based on the results, design guidelines to identify stable IL systems as electrolytes in high voltage Li-ion battery applications are provided.

  16. Mesophases in Nearly 2D Room-Temperature Ionic Liquids

    E-print Network

    N. Manini; M. Cesaratto; M. G. Del Popolo; P. Ballone

    2009-10-27

    Computer simulations of (i) a [C12mim][Tf2N] film of nanometric thickness squeezed at kbar pressure by a piecewise parabolic confining potential reveal a mesoscopic in-plane density and composition modulation reminiscent of mesophases seen in 3D samples of the same room-temperature ionic liquid (RTIL). Near 2D confinement, enforced by a high normal load, relatively long aliphatic chains are strictly required for the mesophase formation, as confirmed by computations for two related systems made of (ii) the same [C12mim][Tf2N] adsorbed at a neutral solid surface and (iii) a shorter-chain RTIL ([C4mim][Tf2N]) trapped in the potential well of part i. No in-plane modulation is seen for ii and iii. In case ii, the optimal arrangement of charge and neutral tails is achieved by layering parallel to the surface, while, in case iii, weaker dispersion and packing interactions are unable to bring aliphatic tails together into mesoscopic islands, against overwhelming entropy and Coulomb forces. The onset of in-plane mesophases could greatly affect the properties of long-chain RTILs used as lubricants.

  17. Ionic Liquid-Based Fluorescein Colorimetric pH Nanosensors

    PubMed Central

    Das, Susmita; Magut, Paul K. S.; de Rooy, Sergio L.; Hasan, Farhana; Warner, Isiah M.

    2014-01-01

    A novel pH sensitive, colorimetric ionic liquid nanosensor based on phosphonium salts of fluorescein is reported. Herein, fluorescein salts of various stoichiometries were synthesized by use of a trihexyltetradecylphosphonium cation [TTP]+ in combination with dianionic [FL]2? and monoanionic [FL]? fluorescein. Nanomaterials derived from these two compounds yielded contrasting colorimetric responses in neutral and acidic environments. Variations in fluorescence spectra as a function of pH were also observed. Examination of TEM and DLS data revealed significant expansion in the diameter of [TTP]2[FL] nanodroplets in acidic environments of variable pHs. A similar trend was also observed for [TTP][FL] nanoparticles. The pH dependent colorimetric and other optical properties of these nanomaterials are attributed to alterations in molecular orientations and stacking as suggested by measuring the absorption, fluorescence, and zeta potential. Since the pH is an important indicator for many diseases, including cancer, these nanosensors are considered to be potential candidates for biomedical applications. PMID:25264488

  18. Thermophysical properties of sulfonium- and ammonium-based ionic liquids

    PubMed Central

    Bhattacharjee, Arijit; Luís, Andreia; Lopes-da-Silva, José A.; Freire, Mara G.; Carvalho, Pedro J.; Coutinho, João A. P.

    2014-01-01

    Experimental data for the density, viscosity, refractive index and surface tension of four sulfonium- and ammonium-based Ionic Liquids (ILs) with the common bis(trifluoromethylsulfonyl)imide anion were measured in the temperature range between 288.15 and 353.15 K and at atmospheric pressure. The ILs considered include butyltrimethylammonium bis(trifluoromethylsulfonyl)imide, [N4111][NTf2], tributylmethylammonium bis(trifluoromethylsulfonyl)imide, [N4441][NTf2], diethylmethylsulfonium bis(trifluoromethylsulfonyl)imide, [S221][NTf2], and triethylsulfonium bis(trifluoromethylsulfonyl)imide, [S222][NTf2]. Based on the gathered results and on data taken from literature, the impact of the cation isomerism and of the size of the aliphatic tails, as well as the effect resulting from the substitution of a nitrogen by a sulfur atom as the cation central atom, on the thermophysical properties of sulfonium- and ammonium-based ILs is here discussed. Remarkably, more symmetric cations present a lower viscosity for the same, and sometimes even for higher, alkyl chain lengths at the cation. Additional derivative properties, such as the isobaric thermal expansion coefficient, the surface thermodynamic properties and the critical temperature for the investigated ILs were also estimated and are presented and discussed. PMID:25516634

  19. Switchable ionic liquids as delignification solvents for lignocellulosic materials.

    PubMed

    Anugwom, Ikenna; Eta, Valerie; Virtanen, Pasi; Mäki-Arvela, Päivi; Hedenström, Mattias; Hummel, Michael; Sixta, Herbert; Mikkola, Jyri-Pekka

    2014-04-01

    The transformation of lignocellulosic materials into potentially valuable resources is compromised by their complicated structure. Consequently, new economical and feasible conversion/fractionation techniques that render value-added products are intensely investigated. Herein an unorthodox and feasible fractionation method of birch chips (B. pendula) using a switchable ionic liquid (SIL) derived from an alkanol amine (monoethanol amine, MEA) and an organic super base (1,8-diazabicyclo-[5.4.0]-undec-7-ene, DBU) with two different trigger acid gases (CO2 and SO2 ) is studied. After SIL treatment, the dissolved fractions were selectively separated by a step-wise method using an antisolvent to induce precipitation. The SIL was recycled after concentration and evaporation of anti-solvent. The composition of undissolved wood after MEA-SO2 -SIL treatment resulted in 80 wt % cellulose, 10 wt % hemicelluloses, and 3 wt % lignin, whereas MEA-CO2 -SIL treatment resulted in 66 wt % cellulose, 12 wt % hemicelluloses and 11 wt % lignin. Thus, the MEA-SO2 -SIL proved more efficient than the MEA-CO2 -SIL, and a better solvent for lignin removal. All fractions were analyzed by gas chromatography (GC), Fourier transform infrared spectroscopy (FT-IR), (13) C nuclear magnetic resonance spectroscopy (NMR) and Gel permeation chromatography (GPC). PMID:24616172

  20. Thinning of reverse osmosis membranes by ionic liquids

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

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

  1. Stable ferrofluids of magnetite nanoparticles in hydrophobic ionic liquids

    NASA Astrophysics Data System (ADS)

    Mestrom, Luuk; Lenders, Jos J. M.; de Groot, Rick; Hooghoudt, Tonnis; Sommerdijk, Nico A. J. M.; Vilaplana Artigas, Marcel

    2015-07-01

    Ferrofluids (FFs) of metal oxide nanoparticles in ionic liquids (ILs) are a potentially useful class of magnetic materials for many applications because of their properties related to temperature/pressure stability, hydrophobicity, viscosity and recyclability. In this work, the screening of several designer surfactants for their stabilizing capabilities has resulted in the synthesis of stable FFs of superparamagnetic 7 ± 2 nm magnetite (Fe3O4) nanoparticles in the hydrophobic IL 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([CRMIM][NTf2]). The designed and synthesized 1-butyl-3-(10-carboxydecyl)-1H-imidazol-3-ium bromide (ILC10-COOH) surfactant that combines the same imidazole moiety as the IL with a long alkyl chain ensured compatibility with the IL and increased the steric repulsion between the magnetite nanoparticles sufficiently such that stable dispersions of up to 50 wt% magnetite were obtained according to stability tests in the presence of a magnetic field (0.5–1 Tesla). Cryo-transmission electron microscopy (cryo-TEM) of the IL-based FFs allowed direct visualization of the surfactant-stabilized nanoparticles in the ILs and the native, hardly aggregated state of their dispersion.

  2. Reversible capture of SO2 through functionalized ionic liquids.

    PubMed

    Yang, Dezhong; Hou, Minqiang; Ning, Hui; Ma, Jun; Kang, Xinchen; Zhang, Jianling; Han, Buxing

    2013-07-01

    Emission of SO2 in flue gas from the combustion of fossil fuels leads to severe environmental problems. Exploration of green and efficient methods to capture SO2 is an interesting topic, especially at lower SO2 partial pressures. In this work, ionic liquids (ILs) 1-(2-diethylaminoethyl)-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Et2 NEMim][Tf2 N]) and 1-(2-diethylaminoethyl)-3-methylimidazolium tetrazolate ([Et2 NEMim][Tetz]) were synthesized. The performances of the two ILs to capture SO2 were studied under different conditions. It was demonstrated that the ILs were very efficient for SO2 absorption. The [Et2 NEMim][Tetz] IL designed in this work could absorb 0.47 g(SO2)g(IL)(-1) at 0.0101 MPa SO2 partial pressure, which is the highest capacity reported to date under the same conditions. The main reason for the large capacity was that both the cation and the anion could capture SO2 chemically. In addition, the IL could easily be regenerated, and the very high absorption capacity and rapid absorption/desorption rates were not changed over five repeated cycles. PMID:23681974

  3. Stable ferrofluids of magnetite nanoparticles in hydrophobic ionic liquids.

    PubMed

    Mestrom, Luuk; Lenders, Jos J M; de Groot, Rick; Hooghoudt, Tonnis; Sommerdijk, Nico A J M; Artigas, Marcel Vilaplana

    2015-07-17

    Ferrofluids (FFs) of metal oxide nanoparticles in ionic liquids (ILs) are a potentially useful class of magnetic materials for many applications because of their properties related to temperature/pressure stability, hydrophobicity, viscosity and recyclability. In this work, the screening of several designer surfactants for their stabilizing capabilities has resulted in the synthesis of stable FFs of superparamagnetic 7 ± 2 nm magnetite (Fe3O4) nanoparticles in the hydrophobic IL 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([CRMIM][NTf2]). The designed and synthesized 1-butyl-3-(10-carboxydecyl)-1H-imidazol-3-ium bromide (ILC10-COOH) surfactant that combines the same imidazole moiety as the IL with a long alkyl chain ensured compatibility with the IL and increased the steric repulsion between the magnetite nanoparticles sufficiently such that stable dispersions of up to 50 wt% magnetite were obtained according to stability tests in the presence of a magnetic field (0.5-1 Tesla). Cryo-transmission electron microscopy (cryo-TEM) of the IL-based FFs allowed direct visualization of the surfactant-stabilized nanoparticles in the ILs and the native, hardly aggregated state of their dispersion. PMID:26118409

  4. Designing ionic liquids: the chemical structure role in the toxicity.

    PubMed

    Ventura, Sónia P M; Gonçalves, Ana M M; Sintra, Tânia; Pereira, Joana L; Gonçalves, Fernando; Coutinho, João A P

    2013-01-01

    Ionic liquids (ILs) are a novel class of solvents with interesting physicochemical properties. Many different applications have been reported for ILs as alternatives to organic solvents in chemical and bioprocesses. Despite the argued advantage of having low vapor pressure, even the most hydrophobic ILs show some degree of solubility in water, allowing their dispersion into aquatic systems and raising concerns on its pollutant potential. Moreover, nowadays most widespread notion concerning the ILs toxicity is that there is a direct relationship with their hydrophobicity/lipophilicity. This work aims at enlarging the currently limited knowledge on ILs toxicity by addressing negative impacts in aquatic ecosystems and investigating the possibility of designing hydrophobic ILs of low ecotoxicity, by the manipulation of their chemical structures. The impact of aromaticity on the toxicity of different cations (pyridinium, piperidinium, pyrrolidinium and imidazolium) and hydrophobic anions (bis(trifluoromethylsulfonyl)imide [NTf(2)] and hexafluorophosphate [PF(6)]) was analysed. Concomitantly, several imidazolium-based ILs of the type [C( n )C( m )C( j )im][NTf(2)] were also studied to evaluate the effects of the position of the alkyl chain on the ILs' toxicity. For that purpose, standard assays were performed using organisms of different trophic levels, Vibrio fischeri, Pseudokirchneriella subcapitata and Daphnia magna, allowing to evaluate the consistency of the structure-activity relationships across different biological targets. The results here reported suggest the possibility of designing ILs with an enhanced hydrophobic character and lower toxicity, by elimination of their aromatic nature. PMID:23010869

  5. Ion association of imidazolium ionic liquids in acetonitrile.

    PubMed

    Bešter-Roga?, Marija; Stoppa, Alexander; Buchner, Richard

    2014-02-01

    Molar conductivities, ?, of dilute solutions of the ionic liquids (ILs) 1-ethyl-3-methylimidazolium tetrafluoroborate ([emim][BF4]), 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]), 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]), 1-hexyl-3-methylimidazolium tetrafluoroborate ([hmim][BF4]), and 1-hexyl-3-methylimidazolium bis-(trifluoromethanesulfonyl)amide ([hmim][NTf2]) in acetonitrile (AN) were determined as a function of temperature in the range 273.15-313.15 K. The data were analyzed with Barthel’s lcCM model to obtain limiting molar conductivities, ?(?)(T), and association constants, K(A)°(T) of these electrolytes. The temperature dependence of these parameters, as well as the extracted limiting cation conductivities, ?(i)(?), were discussed. Additionally, dielectric spectra for [hmim][NTf2] + AN were analyzed in terms of ion association and ion solvation and compared with the inference from conductivity. It appears that in dilute solutions the imidazolium ring of the cations is solvated by ?6 AN molecules that are slowed by a factor of ?8-10 compared to the bulk-solvent dynamics. Ion association of imidazolium ILs to contact ion pairs is only moderate, similar to common 1:1 electrolytes in this solvent. PMID:24428618

  6. Mechanism of bismuth telluride exfoliation in an ionic liquid solvent.

    PubMed

    Ludwig, Thomas; Guo, Lingling; McCrary, Parker; Zhang, Zhongtao; Gordon, Haley; Quan, Haiyu; Stanton, Michael; Frazier, Rachel M; Rogers, Robin D; Wang, Hung-Ta; Turner, C Heath

    2015-03-31

    Bismuth telluride (Bi2Te3) is a well-known thermoelectric material that has a layered crystal structure. Exfoliating Bi2Te3 to produce two-dimensional (2D) nanosheets is extremely important because the exfoliated nanosheets possess unique properties, which can potentially revolutionize several material technologies such as thermoelectrics, heterogeneous catalysts, and infrared detectors. In this work, ionic liquid (IL) 1-butyl-3-methylimidazolium chloride ([C4mim]Cl) is used to exfoliate Bi2Te3 nanoplatelets. In both experiments and in molecular dynamics (MD) simulations, the Bi2Te3 nanoplatelets yield a stable dispersion of 2D nanosheets in the IL solvent, and our MD simulations provide molecular-level insight into the kinetics and thermodynamics of the exfoliation process. An analysis of the dynamics of Bi2Te3 during exfoliation indicates that the relative translation (sliding apart) of adjacent layers caused by IL-induced forces plays an important role in the process. Moreover, an evaluation of the MD trajectories and electrostatic interactions indicates that the [C4mim](+) cation is primarily responsible for initiating Bi2Te3 layer sliding and separation, while the Cl(-) anion is less active. Overall, our combined experimental and computational investigation highlights the effectiveness of IL-assisted exfoliation, and the underlying molecular-level insights should accelerate the development of future exfoliation techniques for producing 2D chalcogenide materials. PMID:25760309

  7. Spectroscopic Studies of Imidizolium and Pyridinium Based Ionic Liquids

    NASA Astrophysics Data System (ADS)

    Booth, Ryan; Stearns, Jaime

    2015-03-01

    Ionic liquids (ILs) have been shown to be extremely useful in areas ranging from chemical synthesis to energetic materials. Furthermore, ILs are thought to be a potential replacement for hydrazine as satellite propellants because a subset are hypergolic with nitric acid. While ILs are useful, however, there is a lack of understanding of the microscopic origins for their macroscopic properties (e.g. viscosity). An example of this is that [emim+][tf2N-] is three times less viscous than its methylated counterpart [emmim+][tf2N-] and there is some discord regarding the reason. We have investigated the molecular properties of such IL pairs using UV and IR spectroscopy in the gas phase on both imidozolium and pyridinium-based ([pyr+]) ILs. UV data show that the photophysics of [emmim+][tf2N-] is different than [emim+][tf2N-] in that there is a lack of evidence for the existence of a charge transfer (CT) state (as was seen in [emim+][tf2N-]). Preliminary UV spectra for the [pyr+] ILs show at least two distinct peaks in the region from 208-270 nm, which are tentatively established as CT states between the anion and cation. IR spectra deliver structural information for both sets of ILs and should provide insight into the correlation between microscopic and macroscopic properties.

  8. 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., E-mail: jcoutinho@ua.pt [CICECO, Departamento de Química, Universidade de Aveiro, 3810-193 Aveiro (Portugal)] [CICECO, Departamento de Química, Universidade de Aveiro, 3810-193 Aveiro (Portugal); Gonçalves, Fernando [Departamento de Biologia e CESAM (Centro de Estudos do Ambiente e do Mar), Universidade de Aveiro, 3810-193 Aveiro (Portugal)] [Departamento de Biologia e CESAM (Centro de Estudos do Ambiente e do Mar), Universidade de Aveiro, 3810-193 Aveiro (Portugal); Esperança, José [Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, 2780-901 Oeiras (Portugal)] [Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, 2780-901 Oeiras (Portugal); Mutelet, Fabrice [Laboratoire Réactions et Génie des Procédés, CNRS (UPR3349), Nancy-Université, 1 rue Grandville, BP 20451 54001 Nancy (France)] [Laboratoire Réactions et Génie des Procédés, CNRS (UPR3349), Nancy-Université, 1 rue Grandville, BP 20451 54001 Nancy (France)

    2014-02-14

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

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

    PubMed

    Kiszkiel, Ilona; Starczewska, Barbara; Le?niewska, Barbara; Pó?niak, 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). PMID:25498149

  10. Ionic liquids and deep eutectic mixtures: sustainable solvents for extraction processes.

    PubMed

    Pena-Pereira, Francisco; Namie?nik, Jacek

    2014-07-01

    In recent years, ionic liquids and deep eutectic mixtures have demonstrated great potential in extraction processes relevant to several scientific and technological activities. This review focuses on the applicability of these sustainable solvents in a variety of extraction techniques, including but not limited to liquid- and solid-phase (micro) extraction, microwave-assisted extraction, ultrasound-assisted extraction and pressurized liquid extraction. Selected applications of ionic liquids and deep eutectic mixtures on analytical method development, removal of environmental pollutants, selective isolation, and recovery of target compounds, purification of fuels, and azeotrope breaking are described and discussed. PMID:24811900

  11. Extraction of Metal Ions from Aqueous Solutions Using Imidazolium Based Ionic Liquids

    Microsoft Academic Search

    Urszula Doma?ska; Anna R?kawek

    2009-01-01

    This article represents a step towards how to choose an ionic liquid as the solvent to improve metal ion (Ag+ and Pb2+) extraction. The liquid-liquid solvent extraction is proposed with the following imidazolium ionic liquids (ILs): 1-ethyl-3-ethylimidazolium,\\u000a or 1-butyl-3-ethylimidazolium, or 1-hexyl-3-ethylimidazolium bis{(trifluoromethyl)sylfonyl}imide [EEIM][NTf2], or [BEIM][NTf2], or [HEIM][NTf2], or 1-butyl-3-ethylimidazolium hexafluorophosphate [BEIM][PF6], or 1-hexyl-3-ethylimidazolium hexafluorophosphate [HEIM][PF6] and the popular 1-butyl-3-methylimidazolium hexafluorophosphate

  12. A Ionic Liquid-Channel Field Effect Transistor

    NASA Astrophysics Data System (ADS)

    Gajar, Stephanie Anne

    A theoretical and experimental study was carried out on a new microfabricated device, an ionic liquid-channel field-effect transistor (ILCFET). The ILCFET resembles a metal-oxide-semiconductor field-effect transistor (MOSFET) except that the current flowing from the source to the drain is carried in thin channels by ions of a liquid electrolyte. Both have an electric field, transverse to the current flow, induced by a gate voltage. Unlike MOSFETs, in which the channel conductance depends on one mobile charge carrier, holes or electrons, the ILCFET channel conductance depends on the concentrations of both cations and anions. Equations for the steady-state channel conductance and the transient response to a step in the gate voltage are derived. The basic steady-state theory assumes no surface binding of ions to surface sites on the channel walls. It predicts that for a channel thickness of 8 Debye lengths and a gate voltage change from 0 to 25 V the average anion concentration will increase by a factor of 9.45 and the average cation concentration will decrease by a factor of 1.88. The effect of surface binding of ions on the steady-state channel conductance is investigated and shown to be significant according to the site-binding model. For the transient response, expressions are derived for the change in gate current and channel conductance with time after the gate voltage has been stepped. The response is modeled as a gate capacitive charging current followed by a slower ambipolar diffusion. Both processes are described by the diffusion equation. The fabricated and tested ILCFETs have fifty parallel channels with total width of 500 mum, lengths of 300, 600, or 900 mum, and thickness of 0.088 mum. The channel walls are rm Si_3N_4/SiO _2 layers which together form a barrier to both ions and electrons. Measurements have been made of conductance vs gate voltage, gate capacitance charging current, and slow conductance changes for acid, base, and salt solutions of glycerol. The conductance vs gate voltage curves agree qualitatively with theory. Experimentally, the slope is typically 10 to 30 times lower than expected and the conductance minimum appears to be shifted to positive gate voltages. The gate current transient response data agree well with theory, but the slow conductance change data indicates that phenomena other than ambipolar diffusion are present. This work is important for the development of two new monolithic devices capable of analyzing ions in solution. One device, an ionic liquid-channel charge-coupled device (ILC-CCD), utilizes the concept of charge-coupling to move ion packets. The other device is a miniature version of capillary electrophoresis with a conductivity detector embedded in the channel at the output. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax. 617-253-1690.) (Abstract shortened by UMI.).

  13. Ionic liquid/ultrasound pretreatment and in situ enzymatic saccharification of bagasse using biocompatible cholinium ionic liquid.

    PubMed

    Ninomiya, Kazuaki; Kohori, Asami; Tatsumi, Mai; Osawa, Koji; Endo, Takatsugu; Kakuchi, Ryohei; Ogino, Chiaki; Shimizu, Nobuaki; Takahashi, Kenji

    2015-01-01

    Choline acetate (ChOAc), a cholinium ionic liquid (IL), showed almost the same bagasse pretreatment capability as 1-ethyl-3-methylimidazolium acetate (EmimOAc), a conventional imidazolium IL used for biomass pretreatment. Moreover, ChOAc showed less of an inhibitory effect on cellulase than EmimOAc. Thus, ChOAc was used for IL/ultrasound-assisted pretreatment and in situ enzymatic saccharification, where IL was not washed out from the pretreated bagasse but diluted with the addition of a buffer solution. When in situ saccharification was performed for 48h in the presence of 10% ChOAc, the cellulose and hemicellulose saccharification percentages were 80% and 72%, respectively. When ChOAc was increased to 20%, the saccharification percentages were 72% and 53%, respectively. However, the values were just 28% and 2%, respectively, in case of 20% EmimOAc. A glucose/xylose solution free from IL and ChOAc aqueous solution without these sugars could be recovered separately by electrodialysis of the hydrolysate of in situ saccharification. PMID:25460999

  14. Application of ionic liquid-based dispersive liquid-liquid microextraction for the analysis of ochratoxin A in rice wines.

    PubMed

    Lai, Xianwen; Ruan, Chunqiang; Liu, Ruicen; Liu, Chenglan

    2014-10-15

    A novel and rapid ionic liquid-based dispersive liquid-liquid microextraction (IL-DLLME) method combined with liquid chromatography and a fluorescence detector for the analysis of ochratoxin A in rice wines is presented. The following parameters were systematically investigated: type and volume of ionic liquid, volume of dispersive solvent, salt addition, sample pH, and vortex time. Rice wine samples were first diluted to 18% alcohol with deionized water, and the pH was adjusted to 3.0. A DLLME procedure was followed that included IL ([HMIM][PF6]) and ethanol as the extraction and dispersive solvents, respectively. Under the optimized experimental conditions, good linearity was obtained with a correlation coefficient (r) of 0.9998 and a limit of detection (LOD) of 0.04?gL(-1). The recoveries ranged from 75.9% to 82.1% with an RSD below 10.4%. The proposed method was successfully applied to analyse OTA samples from several rice wine brands collected in Guangdong province, China. PMID:24837956

  15. Reusable task-specific ionic liquids for a clean ?-caprolactam synthesis under mild conditions.

    PubMed

    Turgis, Raphaël; Estager, Julien; Draye, Micheline; Ragaini, Vittorio; Bonrath, Werner; Lévêque, Jean-Marc

    2010-12-17

    Brønsted-acidic ionic liquids that bear a sulfonic acid group, known as Forbes acids, show a good catalytic activity for the Beckmann rearrangement, used to prepare ?-caprolactam, which is a precursor of Nylon?6. The activity essentially stems from the acidity of the sulfonic acid group. Although these task specific ionic liquids suffer from a high viscosity, this drawback can be circumvented at higher temperatures. A combination of the hydrogen sulfate anion and the sulfonic acid group of the cation is needed to obtain the rearrangement product rapidly under mild conditions. When using an excess of ionic liquid, we postulate that the internal pressure of the ionic medium, generated by the high viscosity and the high number of hydrogen-bonds, is strong enough to contribute to a decrease of the thermodynamic barrier. In accordance with the "Principles of Green Chemistry," we have developed a synthesis of ?-caprolactam that requires no additional chemicals except cyclohexanone oxime and the reusable TSIL. PMID:21117118

  16. Static and transport properties of alkyltrimethylammonium cation-based room-temperature ionic liquids.

    PubMed

    Seki, Shiro; Tsuzuki, Seiji; Hayamizu, Kikuko; Serizawa, Nobuyuki; Ono, Shimpei; Takei, Katsuhito; Doi, Hiroyuki; Umebayashi, Yasuhiro

    2014-05-01

    We have measured physicochemical properties of five alkyltrimethylammonium cation-based room-temperature ionic liquids and compared them with those obtained from computational methods. We have found that static properties (density and refractive index) and transport properties (ionic conductivity, self-diffusion coefficient, and viscosity) of these ionic liquids show close relations with the length of the alkyl chain. In particular, static properties obtained by experimental methods exhibit a trend complementary to that by computational methods (refractive index ? [polarizability/molar volume]). Moreover, the self-diffusion coefficient obtained by molecular dynamics (MD) simulation was consistent with the data obtained by the pulsed-gradient spin-echo nuclear magnetic resonance technique, which suggests that computational methods can be supplemental tools to predict physicochemical properties of room-temperature ionic liquids. PMID:24702446

  17. Liquid-liquid extraction of europium(III) and other trivalent rare-earth ions using a non-fluorinated functionalized ionic liquid.

    PubMed

    Rout, Alok; Binnemans, Koen

    2014-01-28

    A new non-fluorinated malonamide-based ionic liquid extractant was synthesized and investigated for the extraction behavior of europium(III) and other trivalent rare-earth ions from nitric acid medium. The extractant was the functionalized ionic liquid trihexyl(tetradecyl)phosphonium N,N,N',N'-tetra(2-ethylhexyl)malonate, [P66614][MA], and it was used in combination with the non-fluorinated ionic liquid trihexyl(tetradecyl)phosphonium nitrate, [P66614][NO3], as diluents. The extraction behavior of europium in this ionic liquid solution was studied as a function of various parameters such as the pH, concentration of the extractant, the type of acidic medium, temperature, concentration of the salting-out agent and the metal concentration of the aqueous feed. The extraction behavior of [P66614][MA] in [P66614][NO3] was compared with that of [P66614][MA] in the chloride-containing ionic liquid diluent trihexyl(tetradecyl)phosphonium chloride, [P66614][Cl] (Cyphos IL 101). The nitrate system was found to be superior. Marked differences in extraction behavior were observed between [P66614][MA] and the molecular malonamide extractant N,N,N',N'-tetra(2-ethylhexyl)malonamide (TEHMA), i.e. the compound from which the anion of the ionic liquid extractant was prepared. The extraction behavior of other rare earths (La, Ce, Nd, Sm, Ho, Yb) and some transition metals (Ni, Co, Zn) was investigated using this functionalized ionic liquid. A good separation of the rare earths from the transition metals could be achieved. For the rare earths, the extraction efficiency increases over the lanthanide series. The effects of thermodynamic parameters, the stripping of europium(iii) from the ionic liquid and the reusability of the functionalized ionic liquid were studied in detail. PMID:24257814

  18. Ionic-Liquid Lubrication of Sliding MEMS Contacts: Comparison of AFM Liquid Cell and Device-Level Tests

    Microsoft Academic Search

    Josekutty J. Nainaparampil; Kalathil C. Eapen; Jeffrey H. Sanders; Andrey A. Voevodin

    2007-01-01

    Lubrication of microelectromechanical systems (MEMS) became very critical as the devices became complex and its reliability began to deteriorate. In this paper, ionic liquids (ILs) with low volatility and high environmental stability were investigated as lubricants for sliding MEMS devices. A method that is based on atomic force microscopy (AFM) with a liquid cell was developed to study friction and

  19. On the radiation stability of crown ethers in ionic liquids.

    SciTech Connect

    Shkrob, I.; Marin, T.; Dietz, M. (Chemical Sciences and Engineering Division); (Benedictine Univ.); (Univ. of Wisconsin at Milwaukee)

    2011-04-14

    Crown ethers (CEs) are macrocyclic ionophores used for the separation of strontium-90 from acidic nuclear waste streams. Room temperature ionic liquids (ILs) are presently being considered as replacements for traditional molecular solvents employed in such separations. It is desirable that the extraction efficacy obtained with such solvents should not deteriorate in the strong radiation fields generated by decaying radionuclides. This deterioration will depend on the extent of radiation damage to both the IL solvent and the CE solute. While radiation damage to ILs has been extensively studied, the issue of the radiation stability of crown ethers, particularly in an IL matrix, has not been adequately addressed. With this in mind, we have employed electron paramagnetic resonance (EPR) spectroscopy to study the formation of CE-related radicals in the radiolysis of selected CEs in ILs incorporating aromatic (imidazolium and pyridinium) cations. The crown ethers have been found to yield primarily hydrogen loss radicals, H atoms, and the formyl radical. In the low-dose regime, the relative yield of these radicals increases linearly with the mole fraction of the solute, suggesting negligible transfer of the excitation energy from the solvent to the solute; that is, the solvent has a 'radioprotective' effect. The damage to the CE in the loading region of practical interest is relatively low. Under such conditions, the main chemical pathway leading to decreased extraction performance is protonation of the macrocycle. At high radiation doses, sufficient to increase the acidity of the IL solvent significantly, such proton complexes compete with the solvent cations as electron traps. In this regime, the CEs will rapidly degrade as the result of H abstraction from the CE ring by the released H atoms. Thus, the radiation dose to which a CE/IL system is exposed must be maintained at a level sufficiently low to avoid this regime.

  20. On the radiation stability of crown ethers in ionic liquids.

    PubMed

    Shkrob, Ilya A; Marin, Timothy W; Dietz, Mark L

    2011-04-14

    Crown ethers (CEs) are macrocyclic ionophores used for the separation of strontium-90 from acidic nuclear waste streams. Room temperature ionic liquids (ILs) are presently being considered as replacements for traditional molecular solvents employed in such separations. It is desirable that the extraction efficacy obtained with such solvents should not deteriorate in the strong radiation fields generated by decaying radionuclides. This deterioration will depend on the extent of radiation damage to both the IL solvent and the CE solute. While radiation damage to ILs has been extensively studied, the issue of the radiation stability of crown ethers, particularly in an IL matrix, has not been adequately addressed. With this in mind, we have employed electron paramagnetic resonance (EPR) spectroscopy to study the formation of CE-related radicals in the radiolysis of selected CEs in ILs incorporating aromatic (imidazolium and pyridinium) cations. The crown ethers have been found to yield primarily hydrogen loss radicals, H atoms, and the formyl radical. In the low-dose regime, the relative yield of these radicals increases linearly with the mole fraction of the solute, suggesting negligible transfer of the excitation energy from the solvent to the solute; that is, the solvent has a "radioprotective" effect. The damage to the CE in the loading region of practical interest is relatively low. Under such conditions, the main chemical pathway leading to decreased extraction performance is protonation of the macrocycle. At high radiation doses, sufficient to increase the acidity of the IL solvent significantly, such proton complexes compete with the solvent cations as electron traps. In this regime, the CEs will rapidly degrade as the result of H abstraction from the CE ring by the released H atoms. Thus, the radiation dose to which a CE/IL system is exposed must be maintained at a level sufficiently low to avoid this regime. PMID:21410191

  1. Comparative study on the biodegradability of morpholinium herbicidal ionic liquids.

    PubMed

    ?awniczak, ?ukasz; Materna, Katarzyna; Framski, Grzegorz; Szulc, Alicja; Syguda, Anna

    2015-07-01

    This study focused on evaluating the toxicity as well as primary and ultimate biodegradability of morpholinium herbicidal ionic liquids (HILs), which incorporated MCPA, MCPP, 2,4-D or Dicamba anions. The studied HILs were also subjected to determination of surface active properties in order to assess their influence on toxicity and biodegradability. The study was carried out with microbiota isolated from different environmental niches: sediments from river channel, garden soil, drainage trench collecting agricultural runoff stream, agricultural soil and municipal waste repository. The obtained results revealed that resistance to toxicity and biodegradation efficiency of the microbiota increased in the following order: microbiota from the waste repository > microbiota from agricultural soil ? microbiota from an agricultural runoff stream > microbiota from garden soil > microbiota from the river sludge. It was observed that the toxicity of HILs increased with the hydrophobicity of the cation, however the influence of the anion was more notable. The highest toxicity was observed when MCPA was used as the anion (EC50 values ranging from 60 to 190 mg L(-1)). The results of ultimate biodegradation tests indicated that only HILs with 2,4-D as the anion were mineralized to some extent, with slightly higher values for HILs with the 4-decyl-4-ethylmorpholinium cation (10-31 %) compared to HILs with the 4,4-didecylmorpholinium cation (9-20 %). Overall, the cations were more susceptible (41-94 %) to primary biodegradation compared to anions (0-61 %). The obtained results suggested that the surface active properties of the studied HILs may influence their toxicity and biodegradability by bacteria in different environmental niches. PMID:26099357

  2. Fast Enzymatic Saccharification of Switchgrass After Pretreatment with Ionic Liquids

    SciTech Connect

    Zhou, Hua [Argonne National Laboratory (ANL); Baker, Gary A [ORNL; Cowins, Janet V. [Savannah State University

    2010-01-01

    The pretreatment of cellulose using ionic liquids (ILs) has been shown to be an effective method for improving the enzymatic hydrolysis of cellulose; this technique affords a fast and complete saccharification of cellulose into reducing sugars (Dadi et al., Biotechnol Bioeng. 2006; 95:904 910; Liu and Chen, Chinese Sci Bull. 2006; 51:2432 2436; Zhao et al., J Biotechnol. 2009; 139:47 54). Motivated by these advances, this study examines the effect of IL-pretreatment on the enzymatic hydrolysis of purified xylan (as a model system of hemicellulose) and switchgrass (as a real lignocellulose). The IL-pretreatment resulted in no improvement in the hydrolysis of xylan. The likely reason is that pure xylan has a low degree of polymerization (DP), and is readily biodegraded even without any pretreatment. However, in real cellulosic materials (such as switchgrass), xylan is entrapped within the cellulosic matrix, and cannot be conveniently accessed by enzymes. Our data demonstrate that the IL-pretreatment of switchgrass significantly improved the enzymatic saccharification of both cellulose (96% D-glucose yield in 24 h) and xylan (63% D-xylose yield in 24 h). The compositional analysis of switchgrass suggests a lower lignin content after IL-pretreatment. In addition, the infrared spectrum of regenerated switchgrass indicates a lower substrate crystallinity, whereas the enzyme adsorption isotherm further implies that the regenerated substrate is more accessible to enzymes. This study has further confirmed that ILpretreatment is an effective tool in enhancing the enzymatic hydrolysis of cellulosic biomass, and allowing a more complete saccharification.

  3. Electrohydrodynamic patterning of ultra-thin ionic liquid films.

    PubMed

    Nazaripoor, Hadi; Koch, Charles R; Sadrzadeh, Mohtada; Bhattacharjee, Subir

    2015-03-21

    In the electrohydrodynamic (EHD) patterning process, electrostatic destabilization of the air-polymer interface results in micro- and nano-size patterns in the form of raised formations called pillars. The polymer film in this process is typically assumed to behave like a perfect dielectric (PD) or leaky dielectric (LD). In this study, an electrostatic model is developed for the patterning of an ionic liquid (IL) polymer film. The IL model has a finite diffuse electric layer which overcomes the shortcoming of assuming infinitesimally large and small electric diffuse layers inherent in the PD and LD models respectively. The process of pattern formation is then numerically simulated by solving the weakly nonlinear thin film equation using finite difference with pseudo-staggered discretization and an adaptive time step. Initially, the pillar formation process in IL films is observed to be the same as that in PD films. Pillars initially form at random locations and their cross-section increases with time as the contact line expands on the top electrode. After the initial growth, for the same applied voltage and initial film thickness, the number of pillars on IL films is found to be significantly higher than that in PD films. The total number of pillars formed in 1 ?m(2) area of the domain in an IL film is almost 5 times more than that in a similar PD film for the conditions simulated. In addition, the pillar structure size in IL films is observed to be more sensitive to initial film thickness compared to PD films. PMID:25639493

  4. Ionic Liquids as Novel Lubricants and /or Lubricant Additives

    SciTech Connect

    Qu, J. [ORNL; Viola, M. B. [General Motors Company

    2013-10-31

    This ORNL-GM CRADA developed ionic liquids (ILs) as novel lubricants or oil additives for engine lubrication. A new group of oil-miscible ILs have been designed and synthesized with high thermal stability, non-corrosiveness, excellent wettability, and most importantly effective anti-scuffing/anti-wear and friction reduction characteristics. Mechanistic analysis attributes the superior lubricating performance of IL additives to their physical and chemical interactions with metallic surfaces. Working with a leading lubricant formulation company, the team has successfully developed a prototype low-viscosity engine oil using a phosphonium-phosphate IL as an anti-wear additive. Tribological bench tests of the IL-additized formulated oil showed 20-33% lower friction in mixed and elastohydrodynamic lubrication and 38-92% lower wear in boundary lubrication when compared with commercial Mobil 1 and Mobil Clean 5W-30 engine oils. High-temperature, high load (HTHL) full-size engine tests confirmed the excellent anti-wear performance for the IL-additized engine oil. Sequence VID engine dynamometer tests demonstrated an improved fuel economy by >2% for this IL-additized engine oil benchmarked against the Mobil 1 5W-30 oil. In addition, accelerated catalyst aging tests suggest that the IL additive may potentially have less adverse impact on three-way catalysts compared to the conventional ZDDP. Follow-on research is needed for further development and optimization of IL chemistry and oil formulation to fully meet ILSAC GF-5 specifications and further enhance the automotive engine efficiency and durability.

  5. Is There Any Preferential Interaction of Ions of Ionic Liquids with DMSO and H2O? A Comparative Study from MD Simulation.

    PubMed

    Zhao, Yuling; Wang, Jianji; Wang, Huiyong; Li, Zhiyong; Liu, Xiaomin; Zhang, Suojiang

    2015-06-01

    Recently, some binary ionic liquid (IL)/cosolvent systems have shown better performance than the pure ILs in fields such as CO2 absorption, catalysis, cellulose dissolution, and electrochemistry. However, interactions of ILs with cosolvents are still not well understood at the molecular level. In this work, H2O and DMSO were chosen as the representative protic and aprotic solvents to study the effect of cosolvent nature on solvation of a series of ILs by molecular dynamics simulations and quantum chemistry calculations. The concept of preferential interaction of ions was proposed to describe the interaction of cosolvent with cation and anion of the ILs. By comparing the interaction energies between IL and different cosolvents, it was found that there were significantly preferential interactions of anions of the ILs with water, but the same was not true for the interactions of cations/anions of the ILs with DMSO. Then, a detailed analysis and comparison of the interactions in IL/cosolvent systems, hydrogen bonds between cations and anions of the ILs, and the structure of the first coordination shells of the cations and the anions were performed to reveal the existing state of ions at different molar ratios of the cosolvent to a given IL. Furthermore, a systematic knowledge for the solvation of ions of the ILs in DMSO was given to understand cellulose dissolution in IL/cosolvent systems. The conclusions drawn from this study may provide new insight into the ionic solvation of ILs in cosolvents, and motivate further studies in the related applications. PMID:25970011

  6. A novel deep eutectic solvent-based ionic liquid used as electrolyte for dye-sensitized solar cells

    Microsoft Academic Search

    Huei-Ru Jhong; David Shan-Hill Wong; Chi-Chao Wan; Yung-Yun Wang; Tzu-Chien Wei

    2009-01-01

    We utilize a quaternary ammonium salt-derivative ionic liquid called G.CI which is a eutectic mixture of glycerol and choline iodide as electrolyte for dye-sensitized solar cells. Such eutectic compound belongs to a new series of ionic liquid called deep eutectic solvents (DES), which possess many outstanding features compared to the traditional imidazolium-based ionic liquids including cheap raw materials, simple preparation

  7. Tribological performance of phosphonium based ionic liquids for an aluminum-on-steel system and opinions on lubrication mechanism

    Microsoft Academic Search

    XuQing Liu; Feng Zhou; YongMin Liang; WeiMin Liu

    2006-01-01

    A series of asymmetrical tetraalkylphosphonium ionic liquids were synthesized and evaluated as a new kind of lubricant for the contacts of steel\\/Al using an Optimol SRV oscillating friction and wear tester in ambient condition. The phosphonium ionic liquid shows excellent tribological performance and is superior to the conventional ionic liquids 1-ethy-3-hexylimidazolium hexafluorophosphate (P206) in terms of anti-wear performance and load-carrying

  8. High-Temperature Tribological Properties of 2-Substituted Imidazolium Ionic Liquids for Si 3 N 4 Steel Contacts

    Microsoft Academic Search

    Meihuan Yao; Yongmin Liang; Yanqiu Xia; Feng Zhou; Xuqing Liu

    2008-01-01

    Novel ionic liquid lubricants based on monocationic and dicationic 2-substituted imidazolium ionic liquids were synthesized\\u000a and evaluated as lubricants at 250 °C. Results showed that both monocationic and dicationic 2-substituted imidazolium ionic\\u000a liquids with bis(trifluoromethylsulfonyl)imide anion have excellent friction-reducing and anti-wear properties at high temperature,\\u000a which is ascribed to the high chemical and thermal inertness.

  9. Friction and wear behaviors of ionic liquid of alkylimidazolium hexafluorophosphates as lubricants for steel\\/steel contact

    Microsoft Academic Search

    Haizhong Wang; Qiming Lu; Chengfeng Ye; Weimin Liu; Zhaojie Cui

    2004-01-01

    Ionic liquids of the alkylimidazolium hexafluorophosphate type were prepared and evaluated as lubricants for the contact of steel\\/steel. Their tribological properties of the synthetic ionic liquid as the lubricants were investigated on an Optimol SRV oscillating friction and wear tester in ambient condition and on a CZM vacuum friction tester at 1×10?3Pa. These synthetic ionic liquids show excellent tribological performance

  10. Correlation of the Melting Points of Potential Ionic Liquids (Imidazolium Bromides and Benzimidazolium Bromides) Using the CODESSA Program

    Microsoft Academic Search

    Alan R. Katritzky; Ritu Jain; Andre Lomaka; Ruslan Petrukhin; Mati Karelson; Ann E. Visser; Robin D. Rogers

    2002-01-01

    The melting points of several imidazolium-based ionic liquids or ionic liquid analogues were correlated using the CODESSA program in order to develop predictive tools for determination of suitable ionic liquid salts. The data set consisted of melting point data ( °C) for 104 substituted imidazolium bromides divided on the basis of the N-substituents into three subsets: A-57 compounds, B-29 compounds,

  11. Desulfurization From Model of Gasoline by Extraction With Synthesized [BF4]- and [PF6]-based Ionic Liquids

    Microsoft Academic Search

    N. Farzin Nejad; E. Shams; M. Adibi; A. A. Miran Beigi; S. K. Torkestani

    2012-01-01

    The authors report that 1-octyl-3-methylimidazolium tetrafluoroborate, [OMIM][BF4], and 1-butyl-3-methylimidazolium hexafluorophosphate, [BMIM][PF6], ionic liquids were synthesized and tested for their capability to desulfurization from model of gasoline. The results show that the aromatic sulfur compounds with higher ?-electron density were favorably adsorbed. The results also show that [BF4]-based ionic liquid displays higher extraction efficiencies than [PF6]-based ionic liquid. Thus, it was

  12. Studies of ionic liquid solutions by soft X-ray absorption spectroscopy

    Microsoft Academic Search

    Fabio Rodrigues; Gustavo M. do Nascimento; Paulo S. Santos

    2007-01-01

    Soft X-ray spectroscopies give specific information about the electronic structure around light elements. The high absorption of soft X-rays by almost every molecule, including air, requires studies under vacuum, which represents a great limitation. Solids with high vapor pressure and liquids are very difficult to be studied, making solution chemistry almost neglected. This work explores the use of ionic liquids,

  13. NOVEL IONIC LIQUID THERMAL STORAGE FOR SOLAR THERMAL ELECTRIC POWER SYSTEMS

    Microsoft Academic Search

    Banqiu Wu; Ramana G. Reddy; Robin D. Rogers

    Feasibility of ionic liquids as liquid thermal storage media and heat transfer fluids in a solar thermal power plant was investigated. Many ionic liquids such as (C4min)(PF6), (C8mim)(PF6), (C4min)(bistrifluromethane sulflonimide), (C4min)(BF4), (C 8mim)(BF4), and (C4min)( bistrifluromethane sulflonimide) were synthesized and characterized using thermogravimetric analysis (TGA), differential scanning calorimeter (DSC), nuclear magnetic resonance (NMR), viscometry, and some other methods. Properties such

  14. Ionic liquid as soluble support for synthesis of 1,2,3-thiadiazoles and 1,2,3-selenadiazoles.

    PubMed

    Kumar, Anil; Muthyala, Manoj Kumar; Choudhary, Sunita; Tiwari, Rakesh K; Parang, Keykavous

    2012-10-19

    A convenient synthesis of 1,2,3-thiadiazoles and 1,2,3-selenadiazoles was achieved using an ionic liquid as a novel soluble support. Ionic liquid-supported sulfonyl hydrazine was synthesized and reacted with a number of ketones to afford the corresponding ionic liquid-supported hydrazones that were converted to 1,2,3-thiadiazoles in the presence of thionyl chloride. The reaction of ionic liquid-supported hydrazones with selenium dioxide in acetonitrile afforded 1,2,3-selenadiazoles. The advantages of this methodology were the ease of workup, simple reaction conditions, and high purity. PMID:23020655

  15. Ionic-liquid-based dispersive liquid-liquid microextraction for high-throughput multiple food contaminant screening.

    PubMed

    Ho, Yee-Man; Tsoi, Yeuk-Ki; Leung, Kelvin Sze-Yin

    2013-12-01

    This paper describes an innovation of dispersive liquid-liquid microextraction enabling multiple-component analysis of eight high-priority food contaminants in two chemically distinctive families: Sudan dyes and phthalate plasticizers. To provide convenient sample handling for solid and solid-containing matrices, a modified dispersive liquid-liquid microextraction procedure used an extractant precoated frit to perform simultaneous filtration, solvent mixing, and phase dispersion in one simple step. A binary ionic liquid extractant system was carefully tuned to deliver high quality analysis based only on affordable LC with diode array detector instrumentation. The method is comprehensively validated for robust quantification with good precision (6.9-9.8% RSD) in a linear 2-1000 ?g/L range. Having accomplished enrichment factors up to 451, the treatment enables sensitive detection at 0.09-1.01 ?g/L levels. Analysis of six high-risk solid condiments and sauces further verified its practical applicability within a 70-120% recovery range. Compared to other approaches, the current dispersive liquid-liquid microextraction treatment offers major advantages in terms of minimal solvent (1.5 mL) and sample (0.1 g) consumption, ultra-high analytical throughput (6 min), and the ability to handle complex solid matrices. The idea of performing simultaneous analysis for multiple contaminants presented here fosters a more effective mode of operation in food control routines. PMID:24039178

  16. Separation of aromatic hydrocarbons from alkanes using the ionic liquid 1-ethyl-3-methylimidazolium bis{(trifluoromethyl) sulfonyl}amide

    Microsoft Academic Search

    Alberto Arce; Martyn J. Earle; Hector Rodrõ ´ gueza; Kenneth R. Seddonb

    The liquid-liquid equilibrium for the ternary system formed by hexane, benzene and the ionic liquid 1-ethyl-3-methylimidazolium bis{(trifluoromethyl)sulfonyl}amide, (C2mim)(NTf2), has been experimentally determined at 25 uC and 40 uC. The results show that the (C2mim)(NTf2) can selectively remove benzene from its mixtures with hexane, suggesting that this ionic liquid can be used as an alternative solvent in liquid extraction processes for

  17. Decoupling charge transport from the structural dynamics in room temperature ionic liquids

    SciTech Connect

    Griffin, Phillip [University of Tennessee, Knoxville (UTK) & Oak Ridge National Laboratory (ORNL); Agapov, Alexander L [ORNL; Kisliuk, Alexander [ORNL; Sun, Xiao-Guang [ORNL; Dai, Sheng [ORNL; Novikov, Vladimir [ORNL; Sokolov, Alexei P [ORNL

    2011-01-01

    Light scattering and dielectric spectroscopy measurements were performed on the room temperature ionic liquid (RTIL) [C4mim][NTf2] in a broad temperature and frequency range. Ionic conductivity was used to estimate self-diffusion of ions, while light scattering was used to study structural relaxation. We demonstrate that the ionic diffusion decouples from the structural relaxation process as the temperature of the sample decreases toward Tg. The strength of the decoupling appears to be significantly lower than that expected for a supercooled liquid of similar fragility. The structural relaxation process in the RTIL follows well the high-temperature mode coupling theory (MCT) scenario. Using the MCT analysis we estimated the dynamic crossover temperature in [C4mim][NTf2] to be Tc 225 5 K. However, our analysis reveals no sign of the dynamic crossover in the ionic diffusion process.

  18. CuO nanostructures: Optical properties and morphology control by pyridinium-based ionic liquids

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

    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.

  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. PMID:23665738

  20. Structure and Dynamics of Ionic Liquids Confined in Amorphous Porous Chalcogenides.

    PubMed

    Ori, Guido; Massobrio, Carlo; Pradel, Annie; Ribes, Michel; Coasne, Benoit

    2015-06-23

    Besides the abundant literature on ionic liquids in porous silica and carbon, the confinement of such intriguing liquids in porous chalcogenides has received very little attention. Here, molecular simulation is employed to study the structural and dynamical properties of a typical ionic liquid confined in a realistic molecular model of amorphous chalcogenide with various pore sizes and surface chemistries. Using molecular dynamics in the isobaric-isothermal (NPT) ensemble, we consider confinement conditions relevant to real samples. Both the structure and self-dynamics of the confined phase are found to depend on the surface-to-volume ratio of the host confining material. Consequently, most properties of the confined ionic liquid can be written as a linear combination of surface and bulk-like contributions, arising from the ions in contact with the surface and the ions in the pore center, respectively. On the other hand, collective dynamical properties such as the ionic conductivity remain close to their bulk counterpart and almost insensitive to pore size and surface chemistry. These results, which are in fair agreement with available experimental data, provide a basis for the development of novel applications using hybrid organic-inorganic solids consisting of ionic liquids confined in porous chalcogenides. PMID:26030830

  1. Modeling interactions between lignocellulose and ionic liquids using DFT-D.

    PubMed

    Janesko, Benjamin G

    2011-06-21

    Dissolution of lignocellulose in ionic liquids is a promising route to synthesizing fuels and chemical feedstocks from woody plant materials. While cellulose dissolution is well-understood, less is known about the differences between ionic liquids' interactions with cellulose vs. lignin. This work uses dispersion-corrected density functional theory (DFT-D) to model the interactions of imidazolium chloride ionic liquid anions and cations with (1,4)-dimethoxy-?-D-glucopyranose and 1-(4-methoxyphenyl)-2-methoxyethanol as models for cellulose and the lignin polyphenol, respectively. The cellulose model preferentially interacts with Cl(-), confirming previous experimental and theoretical studies. However, the lignin model has significant ?-stacking and hydrogen bonding interactions with imidazolium cation. These results are robust to changes in the computational details, and suggest that the ionic liquid cations play important roles in tuning the relative solubilities of lignin and cellulose. Calculations predict that the extended ?-systems of benzimidazolium ionic liquids yield stronger interactions with lignin, showing potential for improved lignocellulose solvents. PMID:21455515

  2. Determination of halide impurities in ionic liquids by total reflection X-ray fluorescence spectrometry.

    PubMed

    Vander Hoogerstraete, Tom; Jamar, Steven; Wellens, Sil; Binnemans, Koen

    2014-04-15

    The determination and quantification of halide impurities in ionic liquids is highly important because halide ions can significantly influence the chemical and physical properties of ionic liquids. The use of impure ionic liquids in fundamental studies on solvent extraction or catalytic reactions can lead to incorrect experimental data. The detection of halide ions in solution by total reflection X-ray fluorescence (TXRF) has been problematic because volatile hydrogen halide (HX) compounds are formed when the sample is mixed with the acidic metal standard solution. The loss of HX during the drying step of the sample preparation procedure gives imprecise and inaccurate results. A new method based on an alkaline copper standard Cu(NH3)4(NO3)2 is presented for the determination of chloride, bromide, and iodide impurities in ionic liquids. The 1-butyl-3-methylimidazolium ([C4mim]) ionic liquids with the anions acetate ([C4mim][OAc]), nitrate ([C4mim][NO3]), trifluoromethanesulfonate ([C4mim][OTf]), and bis(trifluoromethylsulfonyl)imide ([C4mim][Tf2N]) were synthesized via a halide-free route and contaminated on purpose with known amounts of [C4mim]Cl, [C4mim]Br, [C4mim]I, or potassium halide salts in order to validate the new method and standard. PMID:24628670

  3. Dielectric Properties of Polypropylene-Based Nanocomposites with Ionic Liquid-Functionalized Multiwalled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Xu, Pei; Gui, Haoguan; Hu, Yadong; Bahader, Ali; Ding, Yunsheng

    2014-07-01

    Nanocomposites were prepared from polypropylene (PP) and untreated multiwalled carbon nanotubes (MWCNTs) or MWCNTs surface-functionalized with ionic liquids (MIL), as fillers, and their dielectric properties were compared. The physical (cation-?/?-?) interaction between the ionic liquids and the MWCNTs was apparent from Raman spectroscopy and from thermogravimetric analysis. Morphology characterization revealed that ionic liquids improve the dispersibility of MWCNTs in the PP matrix. It is suggested that the substantial increase in the dielectric permittivity of the nanocomposites compared with that of the PP originates from a remarkable Maxwell-Wagner-Sillars (MWS) effect at percolation threshold where mobile charge carriers are blocked at internal interfaces between the MIL and the PP matrix. The high polarity of ionic liquids may reinforce the MWS effect, and the nonconducting organic groups of the ionic liquids promote the low loss tangent and low conductivity of the MIL/PP nanocomposites. Compared with MWCNTs/PP nanocomposites, lower loss tangent and higher dielectric permittivity were observed for MIL/PP nanocomposites, making the material more attractive for application in electronics.

  4. Ionic liquid assisted hydrothermal fabrication of hierarchically organized ?-AlOOH hollow sphere

    SciTech Connect

    Tang, Zhe, E-mail: tangzhe1983@163.com [State Key Laboratory of Heavy Oil Processing, Key Laboratory of Catalysis, China National Petroleum Corporation (CNPC), China University of Petroleum (East China), Qingdao 266555 (China)] [State Key Laboratory of Heavy Oil Processing, Key Laboratory of Catalysis, China National Petroleum Corporation (CNPC), China University of Petroleum (East China), Qingdao 266555 (China); Liu, Yunqi, E-mail: liuyq@upc.edu.cn [State Key Laboratory of Heavy Oil Processing, Key Laboratory of Catalysis, China National Petroleum Corporation (CNPC), China University of Petroleum (East China), Qingdao 266555 (China)] [State Key Laboratory of Heavy Oil Processing, Key Laboratory of Catalysis, China National Petroleum Corporation (CNPC), China University of Petroleum (East China), Qingdao 266555 (China); Li, Guangci, E-mail: liguangci1984@yahoo.com.cn [State Key Laboratory of Heavy Oil Processing, Key Laboratory of Catalysis, China National Petroleum Corporation (CNPC), China University of Petroleum (East China), Qingdao 266555 (China)] [State Key Laboratory of Heavy Oil Processing, Key Laboratory of Catalysis, China National Petroleum Corporation (CNPC), China University of Petroleum (East China), Qingdao 266555 (China); Hu, Xiaofu, E-mail: hjj19850922@126.cn [State Key Laboratory of Heavy Oil Processing, Key Laboratory of Catalysis, China National Petroleum Corporation (CNPC), China University of Petroleum (East China), Qingdao 266555 (China)] [State Key Laboratory of Heavy Oil Processing, Key Laboratory of Catalysis, China National Petroleum Corporation (CNPC), China University of Petroleum (East China), Qingdao 266555 (China); Liu, Chenguang, E-mail: cgliu@upc.edu.cn [State Key Laboratory of Heavy Oil Processing, Key Laboratory of Catalysis, China National Petroleum Corporation (CNPC), China University of Petroleum (East China), Qingdao 266555 (China)] [State Key Laboratory of Heavy Oil Processing, Key Laboratory of Catalysis, China National Petroleum Corporation (CNPC), China University of Petroleum (East China), Qingdao 266555 (China)

    2012-11-15

    Highlights: ? The ?-AlOOH hollow spheres were synthesized via an ionic liquid-assisted hydrothermal treatment. ? Ionic liquid plays an important role in the morphology of the product. ? Ionic liquid can be easily removed from the product and reused in next experiment. ? A “aggregation–solution–recrystallization” formation mechanism may occur in the system. -- Abstract: Hierarchically organized ?-AlOOH hollow spheres with nanoflake-like porous surface texture have been successfully synthesized via an ionic liquid-assisted hydrothermal synthesis method in citric acid monohydrate (CAMs). It was found that ionic liquid [bmim]{sup +}Cl{sup ?} played an important role in the morphology of the product due to its strong interactions with reaction particles. The samples were characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscope (SEM) and Transmission Electron Microscopy (TEM). The results show that the product has narrow particle size distribution (500–900 nm particle diameter range), high specific surface area (240.5 m{sup 2}/g) and large pore volume (0.61 cm{sup 3}/g). The corresponding ?-Al{sub 2}O{sub 3} hollow spheres can be obtained by calcining it at 550 °C for 3 h. The proposed formation mechanism and other influencing factors of the ?-AlOOH hollow sphere material, such as reaction temperature, reaction duration, CAMs and urea, have also been investigated.

  5. A study of the influence of ionic liquids properties on the Kemp elimination reaction.

    PubMed

    D'Anna, Francesca; La Marca, Sandra; Lo Meo, Paolo; Noto, Renato

    2009-08-10

    The morpholino-induced elimination of 5-nitrobenzisoxazole into the relevant 2-cyano-4-nitrophenolate has been used as a sample reaction in order to investigate molecular properties of some room temperature ionic liquids. The kinetic study was carried out at 298 K by means of spectrophotometric measurements. Ionic liquids, which differ in both their cation and anion properties, were used as solvent systems. In particular, aliphatic (pyrrolidinium, piperidinium, and ammonium) and aromatic (imidazolium and pyridinium) ionic liquids were used. For aromatic cations, imidazolium ions having different hydrogen-bond donor ability or a different alkyl-chain length were taken into account. The anions chosen ([BF(4)(-)], [PF(6)(-)], [SbF(6)(-)], and [NTf(2)(-)]; where NTf(2) = bis(trifluoromethansulfonyl)imide) showed different shape, size, and coordination ability. Solvent parameters of all ionic liquids used were determined by using spectroscopic probes, such as 4-nitroaniline, N,N-diethyl-4-nitroaniline, Nile Red, and Reichardt's dye. Finally, in order to obtain information on the structural organization of the solvent systems, resonance light-scattering measurements were carried out. The collected data provide evidence that ionic liquids are solvent media which exhibit peculiar features, whose effects can be rationalized only considering all parameters affecting their three-dimensional structure. PMID:19562783

  6. Mutual Lewis acid-base interactions of cations and anions in ionic liquids.

    PubMed

    Holzweber, Markus; Lungwitz, Ralf; Doerfler, Denise; Spange, Stefan; Koel, Mihkel; Hutter, Herbert; Linert, Wolfgang

    2013-01-01

    Solute properties are known to be strongly influenced by solvent molecules due to solvation. This is due to mutual interaction as both the properties of the solute and of the solvent strongly depend on each other. The present paper is based on the idea that ionic liquids are cations solvated by anions and anions solvated by cations. To show this (in this system strongly pronounced) interaction the long time established donor-acceptor concept for solvents and ions in solution by Viktor Gutmann is extended to ionic liquids. A number of solvent parameters, such as the Kamlet-Abboud-Taft and the Dimroth-Reichardt E(T) scale for ionic liquids neglect this mutual influence, which, however, seems to be in fact necessary to get a proper description of ionic liquid properties. It is shown how strong such parameters vary when the influence of the counter ion is taken into account. Furthermore, acceptor and donor numbers for ionic liquids are presented. PMID:23180598

  7. Ionic Liquids as Novel Lubricants and Additives for Diesel Engine Applications

    SciTech Connect

    Qu, Jun [ORNL; Blau, Peter Julian [ORNL; Dai, Sheng [ORNL; Luo, Huimin [ORNL; Meyer III, Harry M [ORNL

    2009-01-01

    The lubricating properties of two ionic liquids with the same anion but different cations, one ammonium IL [C8H17]3NH.Tf2N and one imidazolium IL C10mim.Tf2N, were evaluated both in neat form and as oil additives. Experiments were conducted using a standardized reciprocating sliding test using a segment of a Cr-plated diesel engine piston ring against a grey cast iron flat specimen with simulated honing marks as on the engine cylinder liner. The selected ionic liquids were benchmarked against conventional hydrocarbon oils. Substantial friction and wear reductions, up to 55% and 34%, respectively, were achieved for the neat ionic liquids compared to a fully-formulated 15W40 engine oil. Adding 5 vol% ILs into mineral oil has demonstrated significant improvement in the lubricity. One blend even outperformed the 15W40 engine oil with 9% lower friction and 34% less wear. Lubrication regime modeling, worn surface morphology examination, and surface chemical analysis were conducted to help understand the lubricating mechanisms for ionic liquids. Results suggest great potential for using ionic liquids as base lubricants or lubricant additives for diesel engine applications.

  8. Water in ionic liquids at electrified interfaces: the anatomy of electrosorption.

    PubMed

    Feng, Guang; Jiang, Xikai; Qiao, Rui; Kornyshev, Alexei A

    2014-11-25

    Complete removal of water from room-temperature ionic liquids is nearly impossible. For the electrochemical applications of ionic liquids, how water is distributed in the electrical double layers when the bulk liquids are not perfectly dry can potentially determine whether key advantages of ionic liquids, such as a wide electrochemical window, can be harnessed in practical systems. In this paper, we study the adsorption of water on electrode surfaces in contact with humid, imidazolium-based ionic liquids using molecular dynamics simulations. The results revealed that water molecules tend to accumulate within sub-nanometer distance from charged electrodes. At low amount of water in the bulk, the distributions of ions and of electrostatic potential in the double layer are affected weakly by the presence of water, but the spatial distribution of water molecules is strongly dependent on both. The preferential positions of water molecules in double layers are determined by the balance of several factors: the tendency to follow the positions of the maximal absolute value of the electrical field, the association with their ionic surroundings, and the propensity to settle at positions where more free space is available. The balance between these factors changes with charging the electrode, but the adsorption of water generally increases with voltage. The ion specificity of water electrosorption is manifested in the stronger presence of water near positive electrodes (where anions are the counterions) than near negative electrodes (where cations are counterions). These predictions await experimental verification. PMID:25341189

  9. Ionic liquid and water molecules diluted in hydrophobic solvent matrix investigated by infrared absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Kim, Doseok; Sung, Woongmo; Lee, Jonggwan

    2015-03-01

    Pure ionic liquids ([BMIM]: 1-butyl-3-methylimidazolium, X: Cl and I) and their aqueous solutions were loaded on top of non-polar solvent CCl4, and the infrared spectra of CCl4 phase were taken as a function of time for in-situ probing of the transfer of the ionic liquid and water molecules. We observed clear vibrational bands of methyl and methylene groups of the cations similar to that of bulk ionic liquids. On the other hand, normally strong infrared absorption from C(2)-H and C(4,5)-H vibrations was hardly observable. As these bands work as indicators of specific interaction between the imidazolium core and the halide anions, we concluded that ion pairs are fully dissociated and [BMIM] cations exist as monomers in CCl4. For 1 M of [BMIM]Cl and [BMIM]I aqueous solutions, water molecules transferred into CCl4 also exist mostly as monomers, with a possible existence of anion-bound water molecules inferred from the new band at 3421 cm-1 for [BMIM]Cl, and at 3452 cm- 1 for [BMIM]I. Both transfer rate and saturation amount of ionic liquid molecules are larger for [BMIM]I. For this, we propose that this difference in transfer rate originates from excess ionic liquid molecules at the interface between hydrophlic (aqueous solution) and hydrophobic (CCl4) medium.

  10. Protein refolding by N-alkylpyridinium and N-alkyl-N-methylpyrrolidinium ionic liquids.

    PubMed

    Yamamoto, Etsushi; Yamaguchi, Satoshi; Nagamune, Teruyuki

    2011-07-01

    An important property of ionic liquids consisting of cations and anions is that the chemical structures can be easily tuned. To expand the repertoire of effective ionic liquid-based refolding additives, we focused on this tunable property and investigated the effects of new candidates such as N-alkylpyridinium chlorides and N-alkyl-N-methylpyrrolidinium chlorides on protein refolding. Denatured lysozyme (30 mg/mL) was used as a model protein and refolded by 30-fold dilution with various refolding buffers containing different ionic liquids consisting of a systematic variety of alkyl chains. Compared with the refolding yield without additives (lower than 10%), less hydrophobic ionic liquids such as N-ethyl, N-butyl and N-hexylpyridinium chlorides, and N-butyl-N-methylpyrrolidinium chloride were effective in enhancing the refolding yields (46-69%), because they primarily suppressed aggregation because of their chaotropic properties. N-alkylpyridinium cations were more hydrophobic than N-alkyl-N-methylpyrrolidinium cations according to the calculated log P values and prevented aggregation at lower concentrations because of their hydrophobicity. The results provide a range of new effective ionic liquid-based additives for higher protein refolding yields and the knowledge of the effect of chemical structures of additives on protein refolding. PMID:21302144

  11. Morphology and Proton Conductivity of Ionic Liquid Containing Sulfonated Block Copolymers

    NASA Astrophysics Data System (ADS)

    Kim, Sung Yeon; Park, Moon Jeong

    2011-03-01

    Proton exchange membrane fuel cells (PEMFC) offer the prospect of supplying clean electrical power for a wide variety of systems such as portable electronic devices and vehicles. Although, significant effort has been devoted to improvement of the transport properties of PEMs which is operated relatively lower temperature below 80circ; C, it suffers from a CO poisoning at Pt catalysis, complexity of water and heat management in the system. Herein, we report unique block copolymer electrolyte membrane systems containing ionic liquid. Due to the nonvolatile property of ionic liquid the systems exhibit effective proton transport above 100circ; C without humidification. In present study, sulfonated block copolymers, i.e., poly(styrenesulfonate-b-methylbuthylene) (SnMBm), are utilized for matrix materials by varying the ion contents and molecular weight. Imidazolium based ionic liquids are selectively incorporated into polystyrenesulfonate phases, which results in various morphological transitions as a function of the amount of the ionic liquid. The effect of counter ions on the observed morphologies is significant yielding concurrently different values of conductivity. Small angle x-ray scattering and transmission electron microscopy have been employed to determine various morphologies of the ionic liquid containing sulfonated block copolymer membranes and impedance spectroscopy is used for the conductivity measurements.

  12. An ionic electro-active actuator made with graphene film electrode, chitosan and ionic liquid

    NASA Astrophysics Data System (ADS)

    He, Qingsong; Yu, Min; Yang, Xu; Kim, Kwang Jin; Dai, Zhendong

    2015-06-01

    A newly developed ionic electro-active actuator composed of an ionic electrolyte layer sandwiched between two graphene film layers was investigated. Scanning electronic microscopy observation and x-ray diffraction analysis showed that the graphene sheets in the film stacked in a nearly face-to-face fashion but did not restack back to graphite, and the resulting graphene film with low sheet resistance (10 ? sq?1) adheres well to the electrolyte membrane. Contact angle measurement showed the surface energy (37.98 mJ m?2) of the ionic electrolyte polymer is 2.67 times higher than that (14.2 mJ m?2) of the Nafion membrane, contributing to the good adhesion between the graphene film electrode and the electrolyte membrane. An electric double-layer is formed at the interface between the graphene film electrode and the ionic electrolyte membrane under the input potential, resulting in a higher capacitance of 27.6 mF cm?2. We report that this ionic actuator exhibits adequate bending strain, ranging from 0.032 to 0.1% (305 to 945 ?m) as functions of voltage.

  13. Stability of the Liquid State of Imidazolium-Based Ionic Liquids under High Pressure at Room Temperature.

    PubMed

    Yoshimura, Yukihiro; Shigemi, Machiko; Takaku, Mayumi; Yamamura, Misaho; Takekiyo, Takahiro; Abe, Hiroshi; Hamaya, Nozomu; Wakabayashi, Daisuke; Nishida, Keisuke; Funamori, Nobumasa; Sato, Tomoko; Kikegawa, Takumi

    2015-06-25

    To understand the stability of the liquid phase of ionic liquids under high pressure, we investigated the phase behavior of a series of 1-alkyl-3-methylimidazolium tetrafluoroborate ([Cnmim][BF4]) homologues with different alkyl chain lengths for 2 ? n ? 8 up to ?7 GPa at room temperature. The ionic liquids exhibited complicated phase behavior, which was likely due to the conformational flexibility in the alkyl chain. The present results reveal that [Cnmim][BF4] falls into superpressed state around 2-3 GPa range upon compression with an implication of multiple phase or structural transitions to ?7 GPa. Remarkably, a characteristic nanostructural organization in ionic liquids largely diminishes at the superpressed state. The behaviors of imidazolium-based ionic liquids can be classified into, at least, three patterns: (1) pressure-induced crystallization, (2) superpressurization upon compression, and (3) decompression-induced crystallization from the superpressurized glass. Interestingly, the high-pressure phase behavior was relevant to the glass transition behavior at low temperatures and ambient pressure. As n increases, the glass transition pressure (pg) decreases (from 2.8 GPa to ?2 GPa), and the glass transition temperature increases. The results indicate that the p-T range of the liquid phase is regulated by the alkyl chain length of [Cnmim][BF4] homologues. PMID:25988295

  14. High electromagnetic shielding of multi-wall carbon nanotube composites using ionic liquid dispersant

    Microsoft Academic Search

    Jin-Chen Chiu; Chia-Ming Chang; Jhe-Wei Lin; Wood-Hi Cheng

    2008-01-01

    A 2.5 Gbps optical transceiver module fabricated by ionic liquid (IL)-dispersed multi-wall carbon nanotube (MWCNT) composites is demonstrated. In comparison with shielding effectiveness (SE) measurements without dispersion, IL- dispersed MWCNT composites exhibited high SE of 40-46 dB at lower weight percentage of MWCNTs. Ionic charge force and alkyl groups interaction in the IL-MWCNT hybrid solution are the dominant mechanisms to

  15. Excited state proton transfer in ionic liquid mixed micelles.

    PubMed

    Mondal, Tridib; Das, Atanu Kumar; Sasmal, Dibyendu Kumar; Bhattacharyya, Kankan

    2010-10-21

    Excited state proton transfer (ESPT) of pyranine (8-hydroxypyranine-1,3,6-trisulfonate, HPTS) in room temperature ionic liquid (RTIL) mixed micelles is studied by femtosecond up-conversion. The mixed micelle consists of a triblock copolymer, (PEO)(20)-(PPO)(70)-(PEO)(20) (Pluronic P123), and one of the two RTILs, 1-pentyl-3-methyl-imidazolium bromide ([pmim][Br]) and 1-pentyl-3-methyl-imidazolium tetra-fluoroborate ([pmim][BF(4)]). The size and structure of the mixed micelle vary with the relative amount of the RTIL. For [pmim][Br], the hydrodynamic diameter of the mixed micelle is 26 nm in 0.3 M RTIL and 3500 nm in 3.0 M RTIL. The time constant of initial proton transfer (?(PT)) in P123 micelle (65 ps) is 10 times slower than that (5 ps) in water, while the time constants of recombination (?(rec)) and dissociation (?(diss)) are 2-3 times slower in P123 micelle. On addition of the RTIL, the rate of ESPT is markedly modified. In 0.3 M RTIL-P123 mixed micelle, ?(PT) is shorter than that in P123 micelle. In the mixed micelle, ?(PT) increases with an increase in the concentration of the RTIL (230 ps in 3 M [pmim][Br] and 55 ps in 0.9 M [pmim][BF(4)]). This is attributed to large scale penetration of the P123 micelle by RTIL replacing water molecules. The time constants of proton transfer (?(PT), ?(rec), and ?(diss)) are faster than the slowest component (200-500 ps) of solvation dynamics. It seems that the ultrafast component of solvation (<0.3 ps and <5 ps) is enough for inducing proton transfer. The time constant of the proton transfer (?(PT)) in [pmim][BF(4)]-P123 mixed micelle is longer (?20%) than that in [pmim][Br]-P123 mixed micelle for the same concentration of RTIL. The counterion dependence of ESPT is attributed to the difference in the structure and greater hydrophobicity of the [pmim][BF(4)]. PMID:20863113

  16. Ionic liquid- and surfactant-controlled crystallization of WO3 films.

    PubMed

    Kaper, Helena; Djerdj, Igor; Gross, Silvia; Amenitsch, Heinz; Antonietti, Markus; Smarsly, Bernd M

    2015-07-21

    WO3 films were obtained via evaporation-induced self-assembly (EISA) using ionic surfactants such as long-chain ionic liquids 1-hexadecyl-3-methyl imidazolium chloride and bromide (C16mimCl and C16mimBr, respectively) and cetyltrimethylammonium chloride and bromide (CTAC and CTAB, respectively) as additives. Owing to the presence of the ionic surfactants, WO3 films crystallize in a preferred orientation along the a-axis on different substrates, as evidenced by X-ray diffraction. WO3 films with this orientation show improved electrochromic properties when compared to films with a lower degree of crystallographic orientation, prepared in an analogue fashion. PMID:26102203

  17. A highly concentrated catholyte based on a solvate ionic liquid for rechargeable flow batteries.

    PubMed

    Takechi, Kensuke; Kato, Yuichi; Hase, Yoko

    2015-04-17

    A redox-active supercooled liquid is obtained by forming a "solvate ionic liquid" from a mixture of a stabilized organic radical and a specific Li salt and stabilizing the mixture further below their melting points. As a catholyte, the addition of an appropriate amount of water helps to enhance the electrochemical advantage while maintaining its supercooled nature and the liquid shows a high energy density of 200 W h L(-1) with reversible charge/discharge. PMID:25757722

  18. Equimolar CO(2) capture by imidazolium-based ionic liquids and superbase systems

    SciTech Connect

    Dai, Sheng [ORNL; Wang, Chongmin [Pacific Northwest National Laboratory (PNNL); Luo, Huimin [ORNL; Luo, Xiaoyan [Zhejiang University; Li, Qing [ORNL; Li, Haoran [Zhejiang University

    2010-01-01

    Imidazolium-based ionic liquids continue to attract interest in many areas of chemistry because of their low melting points, relatively low viscosities, ease of synthesis, and good stabilities against oxidative and reductive conditions. However, they are not totally inert under many conditions due to the intrinsic acidity of hydrogen at the C-2 position in the imidazolium cation. In this work, this intrinsic acidity was exploited in combination with an organic superbase for the capture of CO{sub 2} under atmospheric pressure. During the absorption of CO{sub 2}, the imidazolium-based ionic liquid containing an equimolar superbase reacted with CO{sub 2} to form a liquid carboxylate salt so that the equimolar capture of CO{sub 2} with respect to the base was achieved. The effects of ionic liquid structures, types of organic superbases, absorption times, and reaction temperatures on the capture of CO{sub 2} were investigated. Our results show that this integrated ionic liquid-superbase system is capable of rapid and reversible capture of about 1 mol CO{sub 2} per mole of ionic liquid. Furthermore, the captured CO{sub 2} can be readily released by either heating or bubbling N{sub 2}, and recycled with little loss of its capture capability. This efficient and reversible catch-and-release process using the weak acidity of the C-2 proton in nonvolatile imidazolium-based ionic liquids provides a good alternative to the current CO{sub 2} capture methods that use volatile alkanols, amines, or water.

  19. Incorporation of ionic liquid into porous polymer monoliths to enhance the separation of small molecules in reversed-phase high-performance liquid chromatography.

    PubMed

    Wang, Jiafei; Bai, Ligai; Wei, Zhen; Qin, Junxiao; Ma, Yamin; Liu, Haiyan

    2015-06-01

    An ionic liquid was incorporated into the porous polymer monoliths to afford stationary phases with enhanced chromatographic performance for small molecules in reversed-phase high-performance liquid chromatography. The effect of the ionic liquid in the polymerization mixture on the performance of the monoliths was studied in detail. While monoliths without ionic liquid exhibited poor resolution and low efficiency, the addition of ionic liquid to the polymerization mixture provides highly increased resolution and high efficiency. The chromatographic performances of the monoliths were demonstrated by the separations of various small molecules including aromatic hydrocarbons, isomers, and homologues using a binary polar mobile phase. The present column efficiency reached 27 000 plates/m, which showed that the ionic liquid monoliths are alternative stationary phases in the separation of small molecules by high-performance liquid chromatography. PMID:25864707

  20. Solvent extraction of rare-earth ions based on functionalized ionic liquids.

    PubMed

    Sun, Xiaoqi; Luo, Huimin; Dai, Sheng

    2012-02-15

    Three functionalized ionic liquids (ILs), tetrabutylammonium di(2-ethylhexyl)phosphate ([TBA][DEHP]), trioctylmethylammonium di(2-ethylhexyl)phosphate ([TOMA][DEHP]), and trihexyl(tetradecyl)phosphonium di(2-ethylhexyl)phosphate ([THTP][DEHP]), are synthesized and characterized. These ILs are used as DEHP-based ionic extractants and are investigated for rare earth elements (REEs) separation in 1-hexyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C(6)mim][NTf(2)]) and diisopropylbenzene (DIPB) along with di(2-ethylhexyl)phosphoric acid (HDEHP). Solubilities of the DEHP-based ionic extractants in [C(6)mim][NTf(2)] are much better than that of HDEHP in [C(6)mim][NTf(2)]. We herein report the achievement of enhanced extractabilities and selectivities for separation of REEs using DEHP-based ionic extractants in [C(6)mim][NTf(2)]. This work highlights the potential of developing a comprehensive ionic liquid-based extraction strategy for REEs using ionic liquids as both extractant and diluent. PMID:22340127

  1. Physicochemical characterization of morpholinium cation based protic ionic liquids used as electrolytes.

    PubMed

    Brigouleix, Catherine; Anouti, Mérièm; Jacquemin, Johan; Caillon-Caravanier, Magali; Galiano, Hervé; Lemordant, Daniel

    2010-02-11

    New protic ionic liquids (PILs) based on the morpholinium, N-methylmorpholinium, and N-ethyl morpholinium cations have been synthesized through a simple and atom-economic neutralization reaction between N-alkyl morpholine and formic acid. Their densities, refractive indices, thermal properties, and electrochemical windows have been measured. The temperature dependence of their dynamic viscosity and ionic conductivity have also been determined. The results allow us to classify them according to a classical Walden diagram and to evaluate their "fragility". In addition, morpholinium based PILs exhibit a large electrochemical window as compared to other protic ionic liquids (up 2.91 V) and possess relatively high ionic conductivities of 10-16.8 mS x cm(-1) at 25 degrees C and 21-29 mS x cm(-1) at 100 degrees C, and a residual conductivity close to 1.0 mS x cm(-1) at -15 degrees C. PIL-water mixtures exhibit high ionic conductivities up to 65 mS x cm(-1) at 25 degrees C and 120 mS x cm(-1) at 100 degrees C for morpholinium formate with water weight fraction w(w) = 0.6. Morpholinium based PILs studied in this work have a low cost and low toxicity, are good ionic liquids, and prove extremely fragile. They have wide applicable perspectives as electrolytes for fuel cell devices, thermal transfer fluids, and acid-catalyzed reaction media as replacements of conventional solvents. PMID:20085258

  2. Physicochemical Properties of Imidazolium-derived Ionic Liquids with Different C-2 Substitutions

    SciTech Connect

    Liao, Chen [ORNL; Shao, Nan [ORNL; Han, Kee Sung [ORNL; Sun, Xiao-Guang [ORNL; Jiang, Deen [ORNL; Hagaman, Edward {Ed} W [ORNL; Dai, Sheng [ORNL

    2011-01-01

    Five room temperature ionic liquids based on C-2 substituted imidazolium cations and bis(trifluoromethanesulfonyl)imide (TFSI) anion were synthesized and their physicochemical properties: thermal property, density, viscosity, ionic conductivity, self-diffusion coefficients, and electrochemical stability were systematically investigated. The temperature dependence of both viscosity and ionic conductivities of these ionic liquids can be described by Vogel-Fulcher-Tamman (VFT) equation. Compared with the reference, 1-propyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, the introduction of functional groups at the C-2 position generally increased the viscosity and lowered the ionic conductivity. The introduction of ether group ( CH2OCH2CH2CH2CH3) at the C-2 position not only enhanced the reduction stability of the ionic liquids but also exhibited the lowest solid electrolyte interfacial resistance (RSEI). On the contrary, the introduction of a cyano group ( CN) at the C-2 position not only decreased the reduction stability but also adversely increased the SEI resistance. The effect of the C-2 substitution on the reduction stability was explained by the change of the energy level of the lowest unoccupied molecular orbital. The self-diffusion coefficients (D) of each ion were measured by pulsed field gradient nuclear magnetic resonance (PFG-NMR). The lithium transference number (tLi) of 0.5 M LiTFSI/IL solutions calculated from the self-diffusion coefficients was in the range of 0.04 and 0.09.

  3. (Liquid + liquid) equilibria in the binary systems (aliphatic, or aromatic hydrocarbons + 1-ethyl-3-methylimidazolium ethylsulfate, or 1-butyl-3-methylimidazolium methylsulfate ionic liquids)

    Microsoft Academic Search

    Julián García; José S. Torrecilla; Adela Fernández; Mercedes Oliet; Francisco Rodríguez

    2010-01-01

    (Liquid+liquid) equilibria of 14 binary systems composed of n-hexane, n-heptane, benzene, toluene, o-xylene, m-xylene, or p-xylene and 1-ethyl-3-methylimidazolium ethylsulfate, [emim]EtSO4, or 1-butyl-3-methylimidazolium methylsulfate, [bmim]MeSO4, ionic liquids have been done in the temperature range from (293.2 to 333.2)K. The solubility of aliphatic is less than those of the aromatic hydrocarbons. In particular, the solubility of hydrocarbons in both ionic liquids increases

  4. Carbon Dioxide Selective Supported Ionic Liquid Membranes: The Effect of Contaminants

    SciTech Connect

    Luebke, D.R.; Ilconich, J.B.; Myers, C.R.; Pennline, H.W.

    2008-04-01

    The integrated gasification combined cycle (IGCC) is widely viewed as a promising technology for the large scale production of energy in a carbon constrained world. These cycles, which include gasification, contaminant removal, water-gas shift, CO2 capture and compression, and combustion of the reduced-carbon fuel gas in a turbine, often have significant efficiency advantages over conventional combustion technologies. A CO2 selective membrane capable of maintaining performance at conditions approaching those of low temperature water-gas shift (260oC) could facilitate the production of carbon-neutral energy by simultaneously driving the shift reaction to completion and concentrating CO2 for sequestration. Supported ionic liquid membranes (SILMs) have been previously evaluated for this application and determined to be physically and chemically stable to temperatures in excess of 300oC. These membranes were based on ionic liquids which interacted physically with CO2 and diminished considerably in selectivity at higher temperatures. To alleviate this problem, the original ionic liquids were replaced with ionic liquids able to form chemical complexes with CO2. These complexing ionic liquid membranes have a local maximum in selectivity which is observed at increasing temperatures for more stable complexes. Efforts are currently underway to develop ionic liquids with selectivity maxima at temperatures greater than 75oC, the best result to date, but other practical concerns must also be addressed if the membrane is to be realistically expected to function under water-gas shift conditions. A CO2 selective membrane must function not only at high temperature, but also in the presence of all the reactants and contaminants likely to be present in coal-derived fuel gas, including water, CO, and H2S. A study has been undertaken which examines the effects of each of these gases on both complexing and physically interacting supported liquid membranes. In a joint project, researchers at the University of Notre Dame synthesized and characterized ionic liquids, and researchers at the National Energy Technology Laboratory incorporated candidate ionic liquids into supports and evaluated the resulting materials for membrane performance.

  5. Novel halogen-free chelated orthoborate-phosphonium ionic liquids: synthesis and tribophysical properties.

    PubMed

    Shah, Faiz Ullah; Glavatskih, Sergei; MacFarlane, Douglas R; Somers, Anthony; Forsyth, Maria; Antzutkin, Oleg N

    2011-07-28

    We report on the synthesis, characterisation, and physical and tribological properties of halogen-free ionic liquids based on various chelated orthoborate anions with different phosphonium cations, both without halogen atoms in their structure. Important physical properties of the ILs including glass transition temperatures, density, viscosity and ionic conductivity were measured and are reported here. All of these new halogen-free orthoborate ionic liquids (hf-BILs) are hydrophobic and hydrolytically stable liquids at room temperature. As lubricants, these hf-BILs exhibit considerably better antiwear and friction reducing properties under boundary lubrication conditions for steel-aluminium contacts as compared with fully formulated (15W-50 grade) engine oil. Being halogen free these hf-BILs offer a more environmentally benign alternative to ILs being currently developed for lubricant applications. PMID:21687897

  6. 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. PMID:22749125

  7. DEVELOPMENT OF ROOM TEMPERATURE IONIC LIQUIDS FOR APPLICATIONS IN ACTINIDE CHEMISTRY

    SciTech Connect

    W. OLDHAM; D. COSTA; W. SMITH

    2001-05-01

    One area of on-going research in our group at Los Alamos National Laboratory is directed toward characterization of the basic coordination chemistry and electrochemical behavior of f-element ions dissolved in room temperature ionic liquids (RTILs). The ultimate goal of this work is to introduce advanced, environmentally sustainable, nuclear processing and purification strategies into both the DOE complex and the civilian nuclear industry. Efforts to develop ambient temperature electrorefining and/or electrowinning technologies are focused on the design of ionic liquids characterized by extended cathodic stability. In this chapter a summary of the synthesis, physical properties and electrochemical behavior of the ionic liquids used in this work is presented. The feasibility of efficient electrochemical production of high electropositive metals is demonstrated through reversible plating and stripping of sodium and potassium metals.

  8. One-pot synthesis of levulinic acid from cellulose in ionic liquids.

    PubMed

    Shen, Yue; Sun, Jian-Kui; Yi, Yu-Xuan; Wang, Bo; Xu, Feng; Sun, Run-Cang

    2015-09-01

    A simple and effective route for the production of levulinic acid (LA) from cellulose has been developed in SO3H-functionalized ionic liquids. The effects of ionic liquid structures, reaction conditions and combination of metal chlorides with ILs on the yield of LA were investigated, where the highest yield of 39.4% was obtained for 120min in the presence of 1-(4-sulfonic acid) butyl-3-methylimidazolium hydrogen sulphate ([BSMim]HSO4) with addition of H2O. The catalytic activities of ionic liquids depended on the anions and decreased in the order: CF3SO3(-)>HSO4(-)>OAc(-), which was in good agreement with their acidity order. The ILs play a dual solvent-acid role for the cellulose conversion into LA and exhibited favorable catalytic activity over four repeated runs. PMID:26055443

  9. Ionic liquid-based compound droplet microfluidics for 'on-drop' separations and sensing.

    PubMed

    Barikbin, Zahra; Rahman, Md Taifur; Parthiban, Pravien; Rane, Anandkumar S; Jain, Vaibhav; Duraiswamy, Suhanya; Lee, S H Sophia; Khan, Saif A

    2010-09-21

    We present a new and general scheme for analytical applications of droplet-based microfluidics in which flowing droplets function not only as isolated reaction flasks, but are also capable of on-drop separation and sensing. To demonstrate this, we choose ionic liquids as designer fluids whose chemical and physical properties can be tailored in task-specific fashion. We create aqueous-ionic liquid compound droplets with tunable structures using an imidazolium-based ionic liquid, and present two analytical applications-separation of a binary aqueous mixture of organic dyes and dynamic pH sensing-to highlight the salient features of this scheme. By combining designer fluids with designer microfluidic emulsions, our work opens up a rich space of exploration for analytical microfluidics. PMID:20697661

  10. Electric double-layer capacitance between an ionic liquid and few-layer graphene.

    PubMed

    Uesugi, Eri; Goto, Hidenori; Eguchi, Ritsuko; Fujiwara, Akihiko; Kubozono, Yoshihiro

    2013-01-01

    Ionic-liquid gates have a high carrier density due to their atomically thin electric double layer (EDL) and extremely large geometrical capacitance Cg. However, a high carrier density in graphene has not been achieved even with ionic-liquid gates because the EDL capacitance CEDL between the ionic liquid and graphene involves the series connection of Cg and the quantum capacitance Cq, which is proportional to the density of states. We investigated the variables that determine CEDL at the molecular level by varying the number of graphene layers n and thereby optimising Cq. The CEDL value is governed by Cq at n < 4, and by Cg at n > 4. This transition with n indicates a composite nature for CEDL. Our finding clarifies a universal principle that determines capacitance on a microscopic scale, and provides nanotechnological perspectives on charge accumulation and energy storage using an ultimately thin capacitor. PMID:23549208

  11. Cytotoxicity estimation of ionic liquids based on their effective structural features.

    PubMed

    Fatemi, Mohammad H; Izadiyan, Parisa

    2011-07-01

    Cytotoxicity of a diverse set of 227 ionic liquids (taken from UFT/Merck Ionic Liquids Biological Effects Database) containing 94 imidazolium, 53 pyridinium, 23 pyrrolidinium, 22 ammonium, 15 piperidinium, 10 morpholinium, 5 phosphanium, and 5 quinolinium cations in combination with 25 different types of anions to Leukemia Rat Cell Line (IPC-81) was estimated from their structural parameters using quantitative structure - toxicity relationship "QSTR" methodology. Linear and nonlinear models were developed using genetic algorithm (GA), multiple linear regressions (MLR) and multilayer perceptron neural network (MLP NN) approaches. Robustness and reliability of the constructed models were evaluated through internal and external validation methods. Furthermore, chemical applicability domain was determined via leverage approach. In this work, it was revealed that the cationic moieties make the major contribution to cytotoxicity and the anionic parts play a secondary role in cytotoxicity of the ionic liquids studied here. Structural information represented in this work, can be used for a rational design of safer ILs. PMID:21549407

  12. The effect of ionic liquid electrolyte concentrations in dye sensitized solar cell using gel electrolyte

    NASA Astrophysics Data System (ADS)

    Pujiarti, H.; Arsyad, W. S.; Wulandari, P.; Hidayat, R.

    2014-09-01

    Dye Sensitized Solar Cells (DSSCs) have received much attention because of some advantages, such as using environment-friendly materials and requiring less high-tech equipment. Commonly DSSCs are built using conventional electrolyte solution, which is prone to electrolyte leakage and low stability. In this paper, we present the characteristics of DSSCs using gel electrolyte, which was made of ionic liquid and hybrid polymer gel, and the effect of ionic liquid concentration on their characteristics. The hybrid composite polymer was composed of siloxane and ethylene glycol polymer networks. Their working performances were investigated by the current-voltage (J-V) characterizations and small ac impedance measurements, which are correlated with the concentrations of ionic liquid electrolyte. The experimental results showed that cell working performance slightly decreased but the solution leakage problem was eliminated.

  13. Dissolution and dissolved state of cytochrome C in a neat, hydrophilic ionic liquid.

    PubMed

    Bihari, Malvika; Russell, Thomas P; Hoagland, David A

    2010-11-01

    The dissolution and dissolved molecular state of cytochrome c were investigated in the room temperature ionic liquid ethylmethylimidazolium ethylsulfate, [EMIM][EtSO4], by viscometry, optical and vibrational spectroscopies, and peroxidase activity. In dilute mixtures, viscometry demonstrated true molecular dissolution of cytochrome c in the ionic liquid and uncovered a molecular size larger than that in aqueous buffer, suggesting altered solvation or slight denaturation. The protein's heme unit absorbs light outside the spectral range masked by [EMIM], enabling conformational assessments by UV-visible and circular dichroism spectroscopies. Adding trends from fluorescence and Fourier transform infrared spectroscopy, unchanged secondary but perturbed tertiary structures were determined, consistent with the appreciable peroxidase activity measured. Different than in aqueous buffers, denaturation is not accompanied by aggregation. Results are relevant to the proposed application of ionic liquids as media for room temperature preservation of biomacromolecules. PMID:20929217

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

    SciTech Connect

    Hussey, Charles L.

    2004-06-01

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

  15. Effect of molecular orientation angle of imidazolium ring on frictional properties of imidazolium-based ionic liquid.

    PubMed

    Watanabe, S; Nakano, M; Miyake, K; Tsuboi, R; Sasaki, S

    2014-07-15

    Ionic liquids have significant potential as lubricants, and it is known that ionic liquids exhibit characteristic behavior at solid-liquid interfaces. Although it is believed that the structure of ionic liquids at the interface contributes to the tribological properties in the region of boundary-mixed lubrication, this contribution has not been clarified because such analysis is difficult. In this research, we clarify the lubrication mechanism of an imidazolium-based ionic liquid by comparing the results of friction tests with interfacial molecular orientation analysis using sum frequency generation spectroscopy. Consequently, we clarify that the tilt angle of the imidazolium ring affects the friction coefficient of the ionic liquid; that is, the larger tilt angle, the lower the friction coefficient. PMID:24942825

  16. Toward an understanding of the salting-out effects in aqueous ionic liquid solutions: vapor-liquid equilibria, liquid-liquid equilibria, volumetric, compressibility, and conductivity behavior.

    PubMed

    Sadeghi, Rahmat; Mostafa, Bahar; Parsi, Elham; Shahebrahimi, Yasaman

    2010-12-16

    The action of particular electrolytes in altering the solution properties of ionic liquids is well documented, although the origin of this effect is not clearly defined. In order to clarify this point, the aim of this work is to obtain further evidence about the salting-out effect produced by the addition of different salts to aqueous solutions of water miscible ionic liquids by evaluating the effect of a large series of salts on the vapor-liquid equilibria, liquid-liquid phase diagram, volumetric, compressibility, and conductometric properties of ionic liquids 1-alkyl-3-methylimidazolium halide ([C(n)mim][X]). In the first part of this work, the experimental measurements of water activity at 298.15 and 308.15 K for aqueous binary and ternary solutions containing 1-alkyl-3-methylimidazolium bromide ([Rmim][Br], R = butyl (C(4)), heptyl (C(7)), and octyl (C(8))), sodium dihydrogen citrate (NaH(2)Cit), disodium hydrogen citrate (Na(2)HCit), and trisodium citrate (Na(3)Cit) are taken using both vapor pressure osmometry (VPO) and improved isopiestic methods. The effect of temperature, charge on the anion of sodium citrate salts, and alkyl chain length of ionic liquids on the vapor-liquid equilibria properties of the investigated systems are studied. The constant water activity lines of all the ternary systems show large negative deviation from the linear isopiestic relation (Zdanovskii-Stokes-Robinson rule) derived using the semi-ideal hydration model, and the vapor pressure depression for a ternary solution is much larger than the sum of those for the corresponding binary solutions with the same molality of the ternary solution. The results have been interpreted in terms of the solute-water and solute-solute interactions. In the second part of this work, the effects of the addition of (NH(4))(3)Cit, K(3)Cit, Na(3)Cit, (NH(4))(2)HPO(4), and (NH(4))(3)PO(4) on the liquid-liquid phase diagram, apparent molar volume, isentropic compressibility, and conductivity of aqueous solutions containing the model ionic liquid 1-butyl-3-methylimidazolium iodide, [C(4)mim][I], are investigated at different temperatures. It was found that there is a relation between the relative concentration of various salts to form two-phase systems with [C(4)mim][I] and apparent molar volume or isentropic compressibility of transfer of [C(4)mim][I] from water to aqueous solutions of the investigated salts. PMID:21080679

  17. NMR Study of Ion Dynamics and Charge Storage in Ionic Liquid Supercapacitors.

    PubMed

    Forse, Alexander C; Griffin, John M; Merlet, Céline; Bayley, Paul M; Wang, Hao; Simon, Patrice; Grey, Clare P

    2015-06-10

    Ionic liquids are emerging as promising new electrolytes for supercapacitors. While their higher operating voltages allow the storage of more energy than organic electrolytes, they cannot currently compete in terms of power performance. More fundamental studies of the mechanism and dynamics of charge storage are required to facilitate the development and application of these materials. Here we demonstrate the application of nuclear magnetic resonance spectroscopy to study the structure and dynamics of ionic liquids confined in porous carbon electrodes. The measurements reveal that ionic liquids spontaneously wet the carbon micropores in the absence of any applied potential and that on application of a potential supercapacitor charging takes place by adsorption of counterions and desorption of co-ions from the pores. We find that adsorption and desorption of anions surprisingly plays a more dominant role than that of the cations. Having elucidated the charging mechanism, we go on to study the factors that affect the rate of ionic diffusion in the carbon micropores in an effort to understand supercapacitor charging dynamics. We show that the line shape of the resonance arising from adsorbed ions is a sensitive probe of their effective diffusion rate, which is found to depend on the ionic liquid studied, as well as the presence of any solvent additives. Taken as whole, our NMR measurements allow us to rationalize the power performances of different electrolytes in supercapacitors. PMID:25973552

  18. NMR Study of Ion Dynamics and Charge Storage in Ionic Liquid Supercapacitors

    PubMed Central

    2015-01-01

    Ionic liquids are emerging as promising new electrolytes for supercapacitors. While their higher operating voltages allow the storage of more energy than organic electrolytes, they cannot currently compete in terms of power performance. More fundamental studies of the mechanism and dynamics of charge storage are required to facilitate the development and application of these materials. Here we demonstrate the application of nuclear magnetic resonance spectroscopy to study the structure and dynamics of ionic liquids confined in porous carbon electrodes. The measurements reveal that ionic liquids spontaneously wet the carbon micropores in the absence of any applied potential and that on application of a potential supercapacitor charging takes place by adsorption of counterions and desorption of co-ions from the pores. We find that adsorption and desorption of anions surprisingly plays a more dominant role than that of the cations. Having elucidated the charging mechanism, we go on to study the factors that affect the rate of ionic diffusion in the carbon micropores in an effort to understand supercapacitor charging dynamics. We show that the line shape of the resonance arising from adsorbed ions is a sensitive probe of their effective diffusion rate, which is found to depend on the ionic liquid studied, as well as the presence of any solvent additives. Taken as whole, our NMR measurements allow us to rationalize the power performances of different electrolytes in supercapacitors. PMID:25973552

  19. Limiting activity coefficients and gas-liquid partition coefficients of various solutes in piperidinium ionic liquids: measurements and LSER calculations.

    PubMed

    Paduszy?ski, Kamil; Doma?ska, Urszula

    2011-06-30

    This paper is a continuation of our systematic investigations on piperidinium ionic liquids and presents new data on activity coefficients at infinite dilution for 43 solutes: linear and branched alkanes, cycloalkanes, alkenes, alkynes, benzene, alkylbenzenes, alcohols, water, thiophene, tetrahyrdofuran (THF), methyl tert-butyl ether (MTBE), linear ethers, acetone, and linear ketones in the ionic liquid 1-butyl-1-methyl-piperidinium bis(trifluoromethylsulfonyl)imide, [BMPIP][NTf2]. The data were determined by gas-liquid chromatography (GLC) at temperatures from 308.15 to 358.15 K. These values were compared to those previously published for the bis-(trifluoromethylsulfonyl)imide-based ionic liquids. The partial molar excess enthalpies ?H1(E,?) and entropies ?S1(E,?) at infinite dilution were calculated from the experimental ?13(?) values obtained over the temperature range. The values of the selectivities for different separation problems were calculated from ?13(?) and compared to literature values for N-methyl-2-pyrrolidinone (NMP), sulfolane, and additional ionic liquids. Experimental limiting activity coefficients were used to calculate gas-IL partition coefficients of solutes, K(L). The modeling with specific linear solvation energy relationship (LSER) equations was performed for data obtained in this work and those reported earlier for 1-butyl-1-methylpiperidinium thiocyanate, [BMPIP][SCN]. PMID:21634373

  20. Molecular dynamics simulation of imidazolium-based ionic liquids. II. Transport coefficients

    NASA Astrophysics Data System (ADS)

    Kowsari, M. H.; Alavi, Saman; Ashrafizaadeh, Mahmud; Najafi, Bijan

    2009-01-01

    A systematic molecular dynamics study is performed to determine the dynamics and transport properties of 12 room-temperature ionic liquids family with 1-alkyl-3-methylimidazolium cation, [amim]+ (alkyl=methyl, ethyl, propyl, and butyl), with counterions, PF6-, NO3-, and Cl-. The goal of the work is to provide molecular level understanding of the transport coefficients of these liquids as guidance to experimentalists on choosing anion and cation pairs to match required properties of ionic liquid solvents. In the earlier paper (Part I), we characterized the dynamics of ionic liquids and provided a detailed comparison of the diffusion coefficients for each ion using the Einstein and Green-Kubo formulas. In this second part, other transport properties of imidazolium salts are calculated, in particular, the electrical conductivity is calculated from the Nernst-Einstein and Green-Kubo formulas. The viscosity is also determined from the Stokes-Einstein relation. The results of the calculated transport coefficients are consistent with the previous computational and experimental studies of imidazolium salts. Generally, the simulations give electrical conductivity lower than experiment while the viscosity estimate is higher than experiment. Within the same cation family, the ionic liquids with the NO3- counterion have the highest electrical conductivities: ?[NO3]->?[PF6]->?[Cl]-. The [dmim][X] series, due to their symmetric cationic structure and good packing and the [bmim][X] series due to higher inductive van der Waals interactions of [bmim]+, have the highest viscosities in these ionic liquid series. Our simulations show that the major factors determining the magnitude of the self-diffusion, electrical conductivity, and viscosity are the geometric shape, ion size, and the delocalization of the ionic charge in the anion.

  1. Molecular dynamics simulation of imidazolium-based ionic liquids. II. Transport coefficients.

    PubMed

    Kowsari, M H; Alavi, Saman; Ashrafizaadeh, Mahmud; Najafi, Bijan

    2009-01-01

    A systematic molecular dynamics study is performed to determine the dynamics and transport properties of 12 room-temperature ionic liquids family with 1-alkyl-3-methylimidazolium cation, [amim](+) (alkyl = methyl, ethyl, propyl, and butyl), with counterions, PF(6)(-), NO(3)(-), and Cl(-). The goal of the work is to provide molecular level understanding of the transport coefficients of these liquids as guidance to experimentalists on choosing anion and cation pairs to match required properties of ionic liquid solvents. In the earlier paper (Part I), we characterized the dynamics of ionic liquids and provided a detailed comparison of the diffusion coefficients for each ion using the Einstein and Green-Kubo formulas. In this second part, other transport properties of imidazolium salts are calculated, in particular, the electrical conductivity is calculated from the Nernst-Einstein and Green-Kubo formulas. The viscosity is also determined from the Stokes-Einstein relation. The results of the calculated transport coefficients are consistent with the previous computational and experimental studies of imidazolium salts. Generally, the simulations give electrical conductivity lower than experiment while the viscosity estimate is higher than experiment. Within the same cation family, the ionic liquids with the NO(3)(-) counterion have the highest electrical conductivities: sigma[NO(3)](-)>sigma[PF(6)](-)>sigma[Cl](-). The [dmim][X] series, due to their symmetric cationic structure and good packing and the [bmim][X] series due to higher inductive van der Waals interactions of [bmim](+), have the highest viscosities in these ionic liquid series. Our simulations show that the major factors determining the magnitude of the self-diffusion, electrical conductivity, and viscosity are the geometric shape, ion size, and the delocalization of the ionic charge in the anion. PMID:19140627

  2. High bulk modulus of ionic liquid and effects on performance of hydraulic system.

    PubMed

    Kambic, Milan; Kalb, Roland; Tasner, Tadej; Lovrec, Darko

    2014-01-01

    Over recent years ionic liquids have gained in importance, causing a growing number of scientists and engineers to investigate possible applications for these liquids because of their unique physical and chemical properties. Their outstanding advantages such as nonflammable liquid within a broad liquid range, high thermal, mechanical, and chemical stabilities, low solubility for gases, attractive tribological properties (lubrication), and very low compressibility, and so forth, make them more interesting for applications in mechanical engineering, offering great potential for new innovative processes, and also as a novel hydraulic fluid. This paper focuses on the outstanding compressibility properties of ionic liquid EMIM-EtSO4, a very important physical chemically property when IL is used as a hydraulic fluid. This very low compressibility (respectively, very high Bulk modulus), compared to the classical hydraulic mineral oils or the non-flammable HFDU type of hydraulic fluids, opens up new possibilities regarding its usage within hydraulic systems with increased dynamics, respectively, systems' dynamic responses. PMID:24526900

  3. High Bulk Modulus of Ionic Liquid and Effects on Performance of Hydraulic System

    PubMed Central

    Kalb, Roland; Tasner, Tadej

    2014-01-01

    Over recent years ionic liquids have gained in importance, causing a growing number of scientists and engineers to investigate possible applications for these liquids because of their unique physical and chemical properties. Their outstanding advantages such as nonflammable liquid within a broad liquid range, high thermal, mechanical, and chemical stabilities, low solubility for gases, attractive tribological properties (lubrication), and very low compressibility, and so forth, make them more interesting for applications in mechanical engineering, offering great potential for new innovative processes, and also as a novel hydraulic fluid. This paper focuses on the outstanding compressibility properties of ionic liquid EMIM-EtSO4, a very important physical chemically property when IL is used as a hydraulic fluid. This very low compressibility (respectively, very high Bulk modulus), compared to the classical hydraulic mineral oils or the non-flammable HFDU type of hydraulic fluids, opens up new possibilities regarding its usage within hydraulic systems with increased dynamics, respectively, systems' dynamic responses. PMID:24526900

  4. Ionic liquids as lubricants of polystyrene and polyamide 6-steel contacts. Preparation and properties of new polymer-ionic liquid dispersions

    Microsoft Academic Search

    J. Sanes; F. J. Carrión; M. D. Bermúdez; G. Martínez-Nicolás

    2006-01-01

    Room-temperature ionic liquids (ILs) have been used as external lubricants in polystyrene (PS) and polyamide 6 (PA6)-steel contacts and as internal lubricants in new polymer-IL dispersions. 1?C\\u000a n\\u000a H2n+1?3?CH3-imidazolium X? [X=BF4; n=2 (IL1), 6 (IL2), 8 (IL3). X=PF6; n=6 (IL4). X=CF3SO3; n=2 (IL5). X=(4?CH3C6H4SO3); n=2 (IL6)] ionic liquids give low friction and extremely mild wear in PS\\/AISI 316L stainless steel

  5. Gelled Ionic Liquid-Based Membranes: Achieving a 10,000 GPU Permeance for Post-Combustion Carbon Capture with Gelled Ionic Liquid-Based Membranes

    SciTech Connect

    None

    2011-02-02

    IMPACCT Project: Alongside Los Alamos National Laboratory and the Electric Power Research Institute, CU-Boulder is developing a membrane made of a gelled ionic liquid to capture CO2 from the exhaust of coal-fired power plants. The membranes are created by spraying the gelled ionic liquids in thin layers onto porous support structures using a specialized coating technique. The new membrane is highly efficient at pulling CO2 out of coal-derived flue gas exhaust while restricting the flow of other materials through it. The design involves few chemicals or moving parts and is more mechanically stable than current technologies. The team is now working to further optimize the gelled materials for CO2 separation and create a membrane layer that is less than 1 micrometer thick.

  6. Thermochemistry of the dissolution and association of ionic liquids in aqueous and acetonitrile solutions

    NASA Astrophysics Data System (ADS)

    Belov, A. V.; Solov'ev, S. N.

    2014-08-01

    The enthalpies of dissolution for three ionic liquids in water and acetonitrile in the field of dilute solutions at 298.15 K are measured in a hermetic highly sensitive calorimeter equipped with an isothermal shell, along with the enthalpies of dilution for aqueous and acetonitrile solutions of the same compounds in moving from three different concentrations to ones that are approximately the same. The enthalpies and constants of the ionic association of such liquids as electrolytes in solutions are calculated, along with their standard enthalpies of dissolution in water and acetonitrile.

  7. Simulating the vibrational spectra of ionic liquid systems: 1-ethyl-3-methylimidazolium acetate and its mixtures.

    PubMed

    Thomas, Martin; Brehm, Martin; Hollóczki, Oldamur; Kelemen, Zsolt; Nyulászi, László; Pasinszki, Tibor; Kirchner, Barbara

    2014-07-14

    The vibrational spectra of the ionic liquid 1-ethyl-3-methylimidazolium acetate and its mixtures with water and carbon dioxide are calculated using ab initio molecular dynamics simulations, and the results are compared to experimental data. The new implementation of a normal coordinate analysis in the trajectory analyzer TRAVIS is used to assign the experimentally observed bands to specific molecular vibrations. The applied computational approaches prove to be particularly suitable for the modeling of bulk phase effects on vibrational spectra, which are highly important for the discussion of the microscopic structure in systems with a strong dynamic network of intermolecular interactions, such as ionic liquids. PMID:25028030

  8. Catalytic oxidation of 1,3-diisopropylbenzene using imidazolium ionic liquid as catalyst

    Microsoft Academic Search

    Shuai Xu; Chongpin Huang; Jie Zhang; Jia Liu; Biaohua Chen

    2009-01-01

    Peroxidation of alkylaromatics is the key step in the synthesis of phenols. Different imidazolium ionic liquids were investigated\\u000a for the oxidation of cumene. The selectivity of cumene hydroperoxide (CHP) increased with different ionic liquids in the order\\u000a [C4mim]Cl4mim]Br4mim]BF44mim]OH. This finding could be interpreted as being due to the partial decomposition of CHP by the acidic proton of the imidazolium\\u000a cation.

  9. Tribological Characteristics of Imidazolium-based Room Temperature Ionic Liquids Under High Vacuum

    Microsoft Academic Search

    Akihito Suzuki; Yoshihiro Shinka; Masabumi Masuko

    2007-01-01

    Tribological characteristics of two imidazolium-based room temperature ionic liquids (RTILs), 1-hexyl-3-methylimidazolium\\u000a tetrafluoroborate, and 1-hexyl-3-methylimidazolium hexafluorophosphate were investigated under high vacuum conditions. Viscosity–temperature\\u000a characteristics and thermogravimetric characteristics of these compounds were also investigated. Imidazolium-based RTILs have\\u000a relatively good viscosity–temperature characteristics that are comparable to those of multiply-alkylated cyclopentane (MAC).\\u000a Thermogravimetric results showed that ionic liquids have high thermal stability and low

  10. Ionic liquid-assisted formation of cellulose/calcium phosphate hybrid materials

    PubMed Central

    Salama, Ahmed; Neumann, Mike; Günter, Christina

    2014-01-01

    Summary Cellulose/calcium phosphate hybrid materials were synthesized via an ionic liquid-assisted route. Scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, infrared spectroscopy, and thermogravimetric analysis/differential thermal analysis show that, depending on the reaction conditions, cellulose/hydroxyapatite, cellulose/chlorapatite, or cellulose/monetite composites form. Preliminary studies with MC3T3-E1 pre-osteoblasts show that the cells proliferate on the hybrid materials suggesting that the ionic liquid-based process yields materials that are potentially useful as scaffolds for regenerative therapies. PMID:25247137

  11. Stable, High-Efficiency Ionic-Liquid-Based Mesoscopic Dye-Sensitized Solar Cells

    Microsoft Academic Search

    Daibin Kuang; Cedric Klein; Zhipan Zhang; Seigo Ito; Jacques-E. Moser; Michael Grätzel

    2007-01-01

    Efficient and stable mesoscopic dye-sensitized solar cells (DSCs) intro- ducing a low-viscosity binary ionic liquid (1-propyl-3-methyl-imidazoli- um iodide (PMII) and 1-ethyl-3-methyl-imidazolium tetracyanoborate (EMIB(CN)4)) electrolyte in combination with a new high-molar-extinc- tion-coefficient ruthenium complex, Ru(2,2'-bipyridine-4,4'-dicarboxylic acid)ACHTUNGTRENNUNG(4,4'-bis(2-(4-tert-butyloxy -phenyl)ethenyl) 2,2'-bipyridine) (NCS)2, are demonstrated. The dependence of photovoltaic performance, charge transport and electron lifetime on the composition of the binary ionic-liquid electrolyte with different

  12. Rapid and Efficient Functionalized Ionic Liquid-Catalyzed Aldol Condensation Reactions Associated with Microwave Irradiation

    PubMed Central

    Wang, Chang; Liu, Jing; Leng, Wenguang; Gao, Yanan

    2014-01-01

    Five quaternary ammonium ionic liquid (IL) and two tetrabutylphosphonium ILs were prepared and characterized. An environmentally benign and convenient functionalized ionic liquid catalytic system was thus explored in the aldol condensation reactions of aromatic aldehydes with acetone. The aldol reactions proceeded more efficiently through microwave-assisted heating than through conventional thermal heating. The yield of products obtained under microwave heating for 30 min was approximately 90%, and the ILs can be recovered and reused at least five times without apparent loss of activity. In addition, this catalytic system can be successfully extended to the Henry reactions. PMID:24445262

  13. Use of ionic liquids as neoteric solvents in the synthesis of fused heterocycles.

    PubMed

    Nevagi, Reshma J; Dighe, Santosh N; Dighe, Satish N; Chaskar, Pratip K; Srinivasan, Kumar V; Jain, Kishor S

    2014-08-01

    Medicinal chemistry has been benefited by combinatorial chemistry and high-throughput parallel synthesis. Ionic liquids reduce the materials and energy intensity of chemical processes and products, minimize or eliminate the dispersion of harmful chemicals in the environment, maximize the use of renewable resources and extend the durability and recyclability of products. It is possible to tune the physical and chemical properties by varying the nature of the cations and anions. Ionic liquids can be easily recovered, cleaned up, and reused repeatedly. PMID:24853356

  14. Desulfurization of gasoline by extraction with N-alkyl-pyridinium-based ionic liquids

    Microsoft Academic Search

    WANG Jian-long; Di-shun ZHAO; Er-peng ZHOU; Zhi DONG

    2007-01-01

    Six N-alkyl-pyridinium-based ionic liquids, N-butyl-pyridinium nitrate ([BPy]NO3), N-ethyl-pyridinium nitrate ([EPy]NO3), N-butyl-pyridinium tetrafluoroborate ([BPy]BF4), N-ethyl-pyridinium tetrafluoroborate ([EPy]BF4), N-ethyl-pyridinium acetate ([EPy]Ac), and N-butyl-pyridinium acetate ([BPy]Ac), were prepared and tested in the extraction desulfurization of gasoline. It is found that [BPy]BF4 has the best effect on the selective removal of sulfur-containing compounds from gasoline at room temperature among these ionic liquids. The extraction

  15. Oligonucleotide Synthesis Using Ionic Liquids as Soluble Supports

    Microsoft Academic Search

    Robert A. Donga; Matthew Hassler; Tak-Hang Chan; Masad J. Damha

    2007-01-01

    The continuing evolution of the methodology for the solution-phase synthesis of oligonucleotides using soluble ionic tags as handles for easy purification is described. This methodology may provide a more cost efficient route for the large scale synthesis of oligonucleotides.

  16. Citrus essential oil terpenless by extraction using 1-ethyl-3-methylimidazolium ethylsulfate ionic liquid: Effect of the temperature

    Microsoft Academic Search

    A. Arce; A. Pobudkowska; O. Rodríguez; A. Soto

    2007-01-01

    Ionic liquids have awakened a big interest as solvents in the last years. In this work, the possibility of using an ionic liquid as solvent for the citrus essential oil deterpenation by liquid–liquid extraction has been studied. Citrus essential oil was simulated as the binary mixture (limonene+linalool) and equilibrium data for limonene+linalool+1-ethyl-3-methylimidazolium ethylsulfate ([emim][EtSO4]) have experimentally been measured at 298.15

  17. Ionic liquids as lubricants of metal-polymer contacts. Preparation and properties of the first dispersions of ionic liquids and nanoparticles in polymers

    Microsoft Academic Search

    Jose Sanes Molina

    2008-01-01

    Room-temperature ionic liquids (ILs) are high performance fluids that stand out because of a wide range of functional properties and exhibit a great potential for engineering applications. Although they have been employed as lubricants in metal-metal, metal-ceramic and ceramic-ceramic contacts, in this thesis we present the first study about the use of ILs as pure lubricants in polymer\\/steel contacts. The

  18. Mutual diffusion in binary mixtures of ionic liquids and molecular liquids by dynamic light scattering (DLS).

    PubMed

    Rausch, Michael Heinrich; Lehmann, Julia; Leipertz, Alfred; Fröba, Andreas Paul

    2011-05-28

    The present study shows that dynamic light scattering (DLS) is capable of measuring mutual diffusion coefficients for binary mixtures of ionic liquids (ILs) with different molecular liquids over the complete composition range. Evidence is given that the light scattering signals are related to true molecular binary diffusion. The method stands out due to its ability to work non-invasively in macroscopic thermodynamic equilibrium with reasonable accuracy and within convenient measurement periods. Compared with other techniques, mixtures with distinctly higher viscosities can be probed. For exemplary binary mixtures of 1-ethyl-3-methylimidazolium ethylsulfate ([EMIM][EtSO(4)]) with acetone, acetonitrile, dichloromethane, ethanol, or water as well as of 1-ethyl-3-methylimidazolium methanesulfonate ([EMIM][MeSO(3)]) with acetone, water, or methanol, mutual diffusivity data were measured over a wide range of composition at a temperature of 293.15 K. In general, the mutual diffusivity increases with increasing mole fraction of the molecular liquid and similarities to aqueous solutions of classical inorganic salts can be found. The characteristic behavior of the mutual diffusion coefficients is influenced by the nature of the chosen molecular liquid. For IL water mixtures, low light scattering intensities were observed despite the large refractive index difference of the pure components. The reason for this behavior may be the existence of water clusters in the mixtures. Additional measurements for IL acetone mixtures at temperatures ranging from 278.15 K to 323.15 K showed that the temperature dependence of the mutual diffusivity can be represented by Arrhenius functions and is increasing for decreasing mole fractions of acetone. PMID:21487585

  19. Solution Phase Parallel Synthesis of 4-Aminophenyl Ethers Using a Carboxyl-Functionalized Ionic Liquid as Support

    Microsoft Academic Search

    Yanqing Peng; Fengping Yi; Gonghua Song; Ying Zhang

    2005-01-01

    Summary. A small sortiment of 4-aminophenyl ether derivatives was constructed with good yields and purities via Williamson reaction using the carboxyl-functionalized ionic liquid [cmmim][BF4] as soluble support. The recovered ionic liquid could be reused for several times with similar capacity.

  20. Hydrodynamic and oxygen mass transfer studies in a three-phase (air–water–ionic liquid) stirred tank bioreactor

    Microsoft Academic Search

    D. Torres-Martínez; R. Melgarejo-Torres; M. Gutiérrez-Rojas; L. Aguilera-Vázquez; M. Micheletti; G. J. Lye; S. Huerta-Ochoa

    2009-01-01

    Recently, room temperature ionic liquids have been investigated as organic solvent replacements in multiphase partitioning bioreactors. They could prove particularly useful for oxidative bioconversions due to their non-volatile and non-flammable nature. In order to promote high mass transfer rates stirred tank bioreactors are normally used. However, for multiphase systems, particularly those featuring ionic liquids, there is little hydrodynamic information available

  1. Radiation stability of cations in ionic liquids. 5. Task-specific ionic liquids consisting of biocompatible cations and the puzzle of radiation hypersensitivity.

    PubMed

    Shkrob, Ilya A; Marin, Timothy W; Wishart, James F; Grills, David C

    2014-09-01

    In 1953, an accidental discovery by Melvin Calvin and co-workers provided the first example of a solid (the ?-polymorph of choline chloride) showing hypersensitivity to ionizing radiation: under certain conditions, the radiolytic yield of decomposition approached 5 × 10(4) per 100 eV (which is 4 orders of magnitude greater than usual values), suggesting an uncommonly efficient radiation-induced chain reaction. Twenty years later, the still-accepted mechanism for this rare condition was suggested by Martyn Symons, but no validation for this mechanism has been supplied. Meanwhile, ionic liquids and deep eutectic mixtures that are based on choline, betainium, and other derivitized natural amino compounds are presently finding an increasing number of applications as diluents in nuclear separations, where the constituent ions are exposed to ionizing radiation that is emitted by decaying radionuclides. Thus, the systems that are compositionally similar to radiation hypersensitive solids are being considered for use in high radiation fields, where this property is particularly undesirable! In Part 5 of this series on organic cations, we revisit the phenomenon of radiation hypersensitivity and explore mechanistic aspects of radiation-induced reactions involving this class of task-specific, biocompatible, functionalized cations, both in ionic liquids and in reference crystalline compounds. We demonstrate that Symons' mechanism needs certain revisions and rethinking, and suggest its modification. Our reconsideration suggests that there cannot be conditions leading to hypersensitivity in ionic liquids. PMID:25127187

  2. Ionic liquids and ionic liquid acids with high temperature stability for fuel cell and other high temperature applications, method of making and cell employing same

    DOEpatents

    Angell, C. Austen (Mesa, AZ); Xu, Wu (Broadview Heights, OH); Belieres, Jean-Philippe (Chandler, AZ); Yoshizawa, Masahiro (Tokyo, JP)

    2011-01-11

    Disclosed are developments in high temperature fuel cells including ionic liquids with high temperature stability and the storage of inorganic acids as di-anion salts of low volatility. The formation of ionically conducting liquids of this type having conductivities of unprecedented magnitude for non-aqueous systems is described. The stability of the di-anion configuration is shown to play a role in the high performance of the non-corrosive proton-transfer ionic liquids as high temperature fuel cell electrolytes. Performance of simple H.sub.2(g) electrolyte/O.sub.2(g) fuel cells with the new electrolytes is described. Superior performance both at ambient temperature and temperatures up to and above 200.degree. C. are achieved. Both neutral proton transfer salts and the acid salts with HSO.sup.-.sub.4 anions, give good results, the bisulphate case being particularly good at low temperatures and very high temperatures. The performance of all electrolytes is improved by the addition of a small amount of involatile base of pK.sub.a value intermediate between those of the acid and base that make the bulk electrolyte. The preferred case is the imidazole-doped ethylammonium hydrogensulfate which yields behavior superior in all respects to that of the industry standard phosphoric acid electrolyte.

  3. Modeling the structure and thermodynamics of ferrocenium-based ionic liquids.

    PubMed

    Bernardes, Carlos E S; Mochida, Tomoyuki; Canongia Lopes, José N

    2015-04-21

    A new force-field for the description of ferrocenium-based ionic liquids is reported. The proposed model was validated by confronting Molecular Dynamics simulations results with available experimental data-enthalpy of fusion, crystalline structure and liquid density-for a series of 1-alkyl-2,3,4,5,6,7,8,9-octamethylferrocenium bis(trifluoromethylsulfonyl)imide ionic liquids, [CnFc][NTf2] (3 ? n ? 10). The model is able to reproduce the densities and enthalpies of fusion with deviations smaller than 2.6% and 4.8 kJ mol(-1), respectively. The MD simulation trajectories were also used to compute relevant structural information for the different [CnFc][NTf2] ionic liquids. The results show that, unlike other ILs, the alkyl side chains present in the cations are able to interact directly with the ferrocenium core of other ions. Even the ferrocenium charged cores (with relatively mild charge densities) are able to form small contact aggregates. This causes the partial rupture of the polar network and precludes the formation of extended nano-segregated polar-nonpolar domains normally observed in other ionic liquids. PMID:25797914

  4. NOvel Fission Product Separation Based on Room-Temperature Ionic liquids

    SciTech Connect

    Hussey, Charles L.

    2005-11-13

    The effective extraction of Cs+ and Sr2+ into a relatively new and heretofore untested hydrophobic ionic liquid, tri-n-butylmethylammonium bis[(trifluoromethyl)sulfonyl]imide was demonstrated with calix[4]arene-bis(tert-octylbenzo-crown-6) and dicyclohexano-18-crown-6, respectively. The coordinated Cs+ and Sr2+ were subsequently removed from the ionic liquid extraction solvent by an electrochemical reduction process carried out at mercury electrodes. This process is non-destructive, permitting the ionic liquid and ionophores to be recycled. Although the process is based on mercury electrodes, this is a benefit rather than a detriment because the liquid mercury containing the Cs and Sr can be easily transported to another electrochemical cell where the Cs and Sr could be electrochemically recovered from the mercury amalgam and concentrated into a minimum volume of water or some other inexpensive solvent. This should facilitate the development of a suitable waste form for the extracted Cs+ and Sr2+. Thus, the feasibility of the proposed ionic liquid-based extraction cycle for the removal of 137Cs+ and 90Sr2+ from simulated aqueous tank waste was demonstrated.

  5. Correlation and Prediction of Dense Fluid Transport Coefficients. IX. Ionic Liquids

    NASA Astrophysics Data System (ADS)

    Gaciño, Félix M.; Comuñas, María J. P.; Fernández, Josefa; Mylona, Sofia K.; Assael, Marc J.

    2014-05-01

    The aim of this paper is to examine the application of a hard-sphere scheme to the correlation and prediction of the viscosity and thermal conductivity of ionic liquids. Ionic liquids present an excellent case, because of their high viscosity. It was found that, regardless of the fact that the scheme had to be extended by orders of magnitude, it was still an excellent scheme for the correlation and prediction of the properties of these liquids; this fact is attributed to its theoretical basis. A database of 461 viscosity and 170 thermal-conductivity measurements for 19 ionic liquids was considered. The average absolute deviation was 2.31 % for the viscosity and 3.15 % for the thermal conductivity, while the expanded uncertainty at the 95 % confidence level was 4.6 % and 6.3 %, respectively. Moreover, if the thermal-conductivity roughness factor is allowed to be temperature dependent, then the average absolute deviation was reduced to 0.91 % for the thermal conductivity, and the expanded uncertainty at the 95 % confidence level to 1.82 %. As the scheme requires knowledge of the density, 1070 measurements of density were employed to derive a Tait-type equation for every ionic liquid considered.

  6. Charge Dynamics and Bending Actuation in Aquivion Membrane Swelled with Ionic Liquids.

    PubMed

    Lin, Junhong; Liu, Yang; Zhang, Q M

    2011-01-21

    The actuation strain and speed of ionic electroactive polymer (EAP) actuators are mainly determined by the charge transport through the actuators and excess ion storage near the electrodes. We employ a recently developed theory on ion transport and storage to investigate the charge dynamics of short-side-chain Aquivion® (Hyflon®) membranes with different uptakes of ionic liquid (IL) 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMI-Tf). The results reveal the existence of a critical uptake of ionic liquids above which the membrane exhibit a high ionic conductivity (?>5×10(-2) mS/cm). Especially, we investigate the charge dynamics under voltages which are in the range for practical device operation (~1 volts and higher). The results show that the ionic conductivity, ionic mobility, and mobile ion concentration do not change with the applied voltage below 1 volt (and for ? below 4 volts). The results also show that bending actuation of the Aquivion membrane with 40 wt% EMI-Tf is much larger than that of Nafion, indicating that the shorter flexible side chains improve the electromechanical coupling between the excess ions and the membrane backbones, while not affect the actuation speed. PMID:21339839

  7. Charge Dynamics and Bending Actuation in Aquivion Membrane Swelled with Ionic Liquids

    PubMed Central

    Lin, Junhong; Liu, Yang; Zhang, Q. M.

    2011-01-01

    The actuation strain and speed of ionic electroactive polymer (EAP) actuators are mainly determined by the charge transport through the actuators and excess ion storage near the electrodes. We employ a recently developed theory on ion transport and storage to investigate the charge dynamics of short-side-chain Aquivion® (Hyflon®) membranes with different uptakes of ionic liquid (IL) 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMI-Tf). The results reveal the existence of a critical uptake of ionic liquids above which the membrane exhibit a high ionic conductivity (?>5×10?2 mS/cm). Especially, we investigate the charge dynamics under voltages which are in the range for practical device operation (~1 volts and higher). The results show that the ionic conductivity, ionic mobility, and mobile ion concentration do not change with the applied voltage below 1 volt (and for ? below 4 volts). The results also show that bending actuation of the Aquivion membrane with 40 wt% EMI-Tf is much larger than that of Nafion, indicating that the shorter flexible side chains improve the electromechanical coupling between the excess ions and the membrane backbones, while not affect the actuation speed. PMID:21339839

  8. Compatiblitity of hydrophobic ionic liquids with high performance cathode materials for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Carnes-Mason, Ezekial Robert

    Lithium batteries are widely seen as the best choice for the future of energy storage but significant improvements are still required. One important area for improvement is searching for new cathode materials that incorporate lithium at higher capacities and voltages. This increases the energy and power available from an individual electrochemical cell, which reduces the number of cells required thereby reducing the size of a battery pack. While several high voltage cathode materials have been discovered, research has been hindered due to safety concerns with current standard electrolytes at high voltages. Ionic liquids are a new class of materials that exhibit excellent electrochemical and thermal stability as well as high ionic conductivity. These qualities make them excellent candidates to replace current battery electrolytes but difficulties in purification and the sheer number of possible chemistries have inhibited their study. In this study four hydrophobic ionic liquids based on pyrrolidinium and piperidinium cations paired with bis(trifluoromethylsulfonyl)imide anions were synthesized using bench top methods. These ionic liquids were successfully incorporated into working half-cells with LiNi1/3Mn1/3Co 1/3O2, a high capacity layered cathode and LiNi0.5Mn 1.5O4, a high voltage spinel type cathode. By comparing the behavior of the ionic liquids a clear relationship between cation size and rate capability was shown. The improved performance and safety at elevated temperatures was also demonstrated showing that ionic liquids are excellent candidates for use as battery electrolytes.

  9. Efficient Sustainable Tool for Monitoring Chemical Reactions and Structure Determination in Ionic Liquids by ESI-MS.

    PubMed

    Khemchyan, Levon L; Khokhlova, Elena A; Seitkalieva, Marina M; Ananikov, Valentine P

    2013-12-01

    An easy and convenient procedure is described for monitoring chemical reactions and characterization of compounds dissolved in ionic liquids using the well-known tandem mass spectrometry (MS/MS) technique. Generation of wastes was avoided by utilizing an easy procedure for analysis of ionic liquid systems without preliminary isolation and purification. The described procedure also decreased the risk of plausible contamination and damage of the ESI-MS hardware and increased sensitivity and accuracy of the measurements. ESI-MS detection in MS/MS mode was shown to be efficient in ionic liquids systems for structural and mechanistic studies, which are rather difficult otherwise. The developed ESI-MS/MS approach was applied to study samples corresponding to peptide systems in ionic liquids and to platform chemical directed biomass conversion in ionic liquids. PMID:24551568

  10. Efficient Sustainable Tool for Monitoring Chemical Reactions and Structure Determination in Ionic Liquids by ESI-MS

    PubMed Central

    Khemchyan, Levon L; Khokhlova, Elena A; Seitkalieva, Marina M; Ananikov, Valentine P

    2013-01-01

    An easy and convenient procedure is described for monitoring chemical reactions and characterization of compounds dissolved in ionic liquids using the well-known tandem mass spectrometry (MS/MS) technique. Generation of wastes was avoided by utilizing an easy procedure for analysis of ionic liquid systems without preliminary isolation and purification. The described procedure also decreased the risk of plausible contamination and damage of the ESI-MS hardware and increased sensitivity and accuracy of the measurements. ESI-MS detection in MS/MS mode was shown to be efficient in ionic liquids systems for structural and mechanistic studies, which are rather difficult otherwise. The developed ESI-MS/MS approach was applied to study samples corresponding to peptide systems in ionic liquids and to platform chemical directed biomass conversion in ionic liquids. PMID:24551568

  11. Polyoxometalate-lyotropic liquid crystal hybrid material formed in room-temperature ionic liquids.

    PubMed

    Jiang, Wenqing; Liu, Liping; Hao, Jingcheng

    2011-03-01

    Manganese(II)-substituted polyoxometalate, Na6(NH4)4[(Mn(II)(H2O)3)2(WO2)2(BiW9O33)2] x 37H2O (POM-Mn), was assembled within lyotropic hexagonal liquid crystal (LLC) formed in the room-temperature ionic liquids (RT-ILs), ethylammonium nitrate (EAN), fabricating the POM-LLC inorganic-organic hybrid materials. Polarized optical microscope images combined with small-angle X-ray scattering (SAXS) results indicate that the introduction of POM-Mn does not destroy the structure of hexagonal LLCs. The increase of d spacing demonstrates the integration of POM-Mn within the basic unit of the hexagonal LLCs. The FTIR spectra of the POM-LLC hybrid material show the characteristic absorption peaks of W-O bond. The rheological results indicate POM-LLC hybrid materials are highly viscoelastic and that the apparent viscosity is enhanced due to the introduction of the POM-Mn. The tribological properties were explored to greatly extend the applications of POM-LLC composites in RT-ILs as lubricating materials. The research of magnetic properties indicates the POM-LLC composite is ferromagnetic, therefore illuminating the potential application in the fields of magnetic materials. PMID:21449365

  12. Ionic liquids as novel stationary phases in gas liquid chromatography: inverse or normal isotope effect?

    PubMed

    Schmarr, Hans-Georg; Slabizki, Petra; Müntnich, Sabrina; Metzger, Carmen; Gracia-Moreno, Elisa

    2012-12-28

    The separation of deuterated and non-deuterated compounds in gas liquid partitioning chromatography (GLC) on silicone type stationary phase usually results in the inverse isotope effect. With ionic liquids (ILs) as stationary phase, however, this may show a totally different nature. The inverse isotope effect, in which heavier (deuterated) isotopic compounds (isotopologues) elute earlier, is to be expected when van der Waals (London) dispersion forces play a dominant role in the solute-stationary phase interaction. Such (apolar) interactions seem to play only a minor role when ILs are the stationary phases, leading to only a marginal inverse isotope effect, e.g. for the separation of 2,4,6-trichloroanisole and its [(2)H(5)]-isotopologue on 1,12-di(tripropylphosphonium) dodecane bis(trifluoromethansulfonyl) amide (commercialized as SLB-IL59, Supelco). Indeed, with the most polar stationary phase available (commercialized as SLB-IL111; Supelco), this separation showed a normal isotope effect. Further examples are presented and the nature of the isotope effect observed is discussed. PMID:23200305

  13. Characterization of surface confined ionic liquid stationary phases: impact of cation revisited.

    PubMed

    VanMiddlesworth, Bradley J; Stalcup, Apryll M

    2014-10-17

    Modification of the Linear Solvation Energy Relationship (LSER) equation to account for ionic interactions in the retention of ionizable compounds has enabled the elucidation in the effect of the imidazolium cation identity on retention. Three Surface Confined Ionic Liquid stationary phases were synthesized from an octylbromide phase on silica: 1-octyl-3-methylimidazolium bromide (MIM), 1-octyl-3-butylimidazolium bromide (BIM), and 1-octyl-3-benzylimidazolium bromide (BzIM). These phases were probed via a 35 analyte probe set, including 6 phenolic acids, 5 anilinic bases, and 2 pyridinic bases, and the resulting column parameters compared with previously reported interactions of ionic liquids or Surface Confined Ionic Liquids. The correlation between experimental and calculated retention for the conventional, 6-parameter LSER equation was very poor: r(2)=0.64 (MIM), 0.60 (BIM), and 0.62 (BzIM). By accounting for the ionic interactions between stationary phase and analytes, linearity for the modified, 8 parameter LSER equation was significantly improved to r(2)=0.997 (MIM), 0.996 (BIM), and 0.997 (BzIM). The primary difference between cation identities is within the retention of acids where BIM>BzIM>MIM. We conjecture that the accessibility of bulky, acidic analytes to the on-top interaction of the imidazolium ring is the major contributor to increased anion retention. PMID:25218629

  14. Two-cation competition in ionic-liquid-modified electrolytes for lithium ion batteries.

    PubMed

    Lee, Sang-Young; Yong, Hyun Hang; Lee, Young Joo; Kim, Seok Koo; Ahn, Soonho

    2005-07-21

    It is a common observation that when ionic liquids are added to electrolytes the performances of lithium ion cells become poor, while the thermal safeties of the electrolytes might be improved. In this study, this behavior is investigated based on the kinetics of ionic diffusion. As a model ionic liquid, we chose butyldimethylimidazolium hexafluorophosphate (BDMIPF(6)). The common solvent was propylene carbonate (PC), and lithium hexafluorophosphate (LiPF(6)) was selected as the lithium conducting salt. Ionic diffusion coefficients are estimated by using a pulsed field gradient NMR technique. From a basic study on the model electrolytes (BDMIPF(6) in PC, LiPF(6) in PC, and BDMIPF(6) + LiPF(6) in PC), it was found that the BDMI(+) from BDMIPF(6) shows larger diffusion coefficients than the Li(+) from LiPF(6). However, the anionic (PF(6)(-)) diffusion coefficients present little difference between the model electrolytes. The higher diffusion coefficient of BDMI(+) than that of Li(+) suggests that the poor C-rate performance of lithium ion cells containing ionic liquids as an electrolyte component can be attributed to the two-cation competition between Li(+) and BDMI(+). PMID:16852712

  15. Performance of Nitrile-Containing Anions in Task-Specific Ionic Liquids for Improved CO2/N2 Separation

    SciTech Connect

    Mahurin, Shannon Mark [ORNL; Lee, Jeseung [ORNL; Baker, Gary A [ORNL; Luo, Huimin [ORNL; Dai, Sheng [ORNL

    2010-01-01

    This work explores the performance of a series of ionic liquids that incorporate a nitrile-containing anion paired to 1-alkyl-3-methylimidazolium cations in tailoring the selectivity and permeance of supported ionic liquid membranes for CO2/N2 separations. The permeance and selectivity of three ionic liquids, each with an increasing number of nitrile groups in the anion (i.e., two, three, and four), were measured using a non-steady-state permeation method. By predictably varying the molar volume and viscosity of the ionic liquids, we show that the solubility, selectivity, and permeance can be optimized for CO2/N2 separation through controlled introduction of the nitrile functionality into the anion. Of the three nitrile-based ionic liquids studied, 1-ethyl-3-methylimidazolium tetracyanoborate, [emim][B(CN)4], showed the highest permeance with a value of 2.55 10 9 mol/(m2 Pa s), a magnitude 30% higher than that of the popular ionic liquid [emim][Tf2N]. This same nitrile-bearing ionic liquid also exhibited a high CO2/N2 selectivity of approximately 53. Additionally, the carbon dioxide solubility for each ionic liquid was measured at room temperature with [emim][B(CN)4] again exhibiting the highest CO2 solubility. Results from our study of the nitrile-based ionic liquids can be rationalized in terms of regular solution theory wherein the selectivity and permeance of a given SILM system are largely determined by the molar volume and viscosity of the corresponding ionic liquid phase.

  16. The Solubility of Ionic Solids and Molecular Liquids

    Microsoft Academic Search

    Carl Baer; Sheila M. Adamus

    1999-01-01

    Solubility is a ubiquitous concept in chemistry, but usually only sparingly soluble salts are examined in the introductory chemistry laboratory. With this two-part experiment, students study more common solubility phenomena. First, solubilities of three ionic salts (NaCl, PbCl2, and KAl(SO4)2.12H2O) in water are measured at four temperatures. The concept of recrystallization is introduced as students cool a high-temperature solution and

  17. Electrochemical Polishing Applications and EIS of a Novel Choline Chloride-Based Ionic Liquid

    SciTech Connect

    Wixtrom, Alex I. [Christopher Newport University, Newport News, VA (United States); Buhler, Jessica E. [Christopher Newport University, Newport News, VA (United States); Reece, Charles E. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Abdel-Fattah, Tarek M. [Christopher Newport University, Newport News, VA (United States)

    2013-06-01

    Minimal surface roughness is a critical feature for high-field superconducting radio frequency (SRF) cavities used to engineer particle accelerators. Current methods for polishing Niobium cavities typically utilize solutions containing a mixture of concentrated sulfuric and hydrofluoric acid. Polishing processes such as these are effective, yet there are many hazards and costs associated with the use (and safe disposal) of the concentrated acid solutions. An alternative method for electrochemical polishing of the cavities was explored using a novel ionic liquid solution containing choline chloride. Potentiostatic electrochemical impedance spectroscopy (EIS) was used to analyze the ionic polishing solution. Final surface roughness of the Nb was found to be comparable to that of the acid-polishing method, as assessed by atomic force microscopy (AFM). This indicates that ionic liquid-based electrochemical polishing of Nb is a viable replacement for acid-based methods for preparation of SRF cavities.

  18. Ionic liquids increase the catalytic efficiency of a lipase (Lip1) from an antarctic thermophilic bacterium.

    PubMed

    Muñoz, Patricio A; Correa-Llantén, Daniela N; Blamey, Jenny M

    2015-01-01

    Lipases catalyze the hydrolysis and synthesis of triglycerides and their reactions are widely used in industry. The use of ionic liquids has been explored in order to improve their catalytic properties. However, the effect of these compounds on kinetic parameters of lipases has been poorly understood. A study of the kinetic parameters of Lip1, the most thermostable lipase from the supernatant of the strain ID17, a thermophilic bacterium isolated from Deception Island, Antarctica, and a member of the genus Geobacillus is presented. Kinetic parameters of Lip1 were modulated by the use of ionic liquids BmimPF6 and BmimBF4. The maximum reaction rate of Lip1 was improved in the presence of both salts. The highest effect was observed when BmimPF6 was added in the reaction mix, resulting in a higher hydrolytic activity and in a modulation of the catalytic efficiency of the enzyme. However, the catalytic efficiency did not change in the presence of BmimBF4. The increase of the reaction rates of Lip1 promoted by these ionic liquids could be related to possible changes in the Lip1 structure. This effect was measured by quenching of tryptophan fluorescence of the enzyme, when it was incubated with each liquid salt. In conclusion, the hydrolytic activity of Lip1 is modulated by the ionic liquids BmimBF4 and BmimPF6, improving the reaction rate and the catalytic efficiency of this enzyme when BmimPF6 was used. This effect is probably due to changes in the structure of Lip1 induced by the presence of these ionic liquids, stimulating its catalytic activity. PMID:25425150

  19. Cloud Point Extraction of Parabens Using Non-Ionic Surfactant with Cylodextrin Functionalized Ionic Liquid as a Modifier

    PubMed Central

    Noorashikin, Md Saleh; Raoov, Muggundha; Mohamad, Sharifah; Abas, Mhd Radzi

    2013-01-01

    A cloud point extraction (CPE) process using non-ionic surfactant (DC193C) to extract selected paraben compounds from water samples was investigated using reversed phase high performance liquid chromatography (RP-HPLC). The CPE process with the presence of ?-cyclodextrin (?CD) functionalized ionic liquid as a modifier (CPE-DC193C-?CD-IL) is a new extraction technique that has been applied on the optimization of parameters, i.e., pH, ?CD-IL concentration and phase volume ratio. This CPE-DC193C-?CD-IL method is facilitated at 30 °C, showing great losses of water content in the surfactant-rich phase, resulting in a high pre-concentration factor and high distribution coefficient. The developed method CPE-DC193C-?CD-IL did show enhanced properties compared to the CPE method without the modifier (CPE-DC193C). The developed method of CPE-DC193C-?CD-IL gives an excellent performance on the detection of parabens from water samples with the limit of detection falling in the range of 0.013–0.038 ?g mL?1. Finally, the inclusion complex formation, hydrogen bonding, and ?–? interaction between the ?CD-IL, benzyl paraben (ArP), and DC 193C were proven using 1H NMR and 2D NOESY spectroscopy. PMID:24351832

  20. Manipulation of ionic liquid anion-solute-antisolvent interactions for the purification of acetaminophen.

    PubMed

    Weber, C C; Kunov-Kruse, A J; Rogers, R D; Myerson, A S

    2015-03-11

    Hydrogen bond donating cosolvents have been shown to significantly reduce the solubility of acetaminophen (AAP) in ionic liquids containing the acetate anion. Reduced solubility arises from competition for solvation by the acetate anion and can be used for the design of advanced separation techniques, illustrated by the crystallization of AAP. PMID:25673089