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1

Interactions in ion pairs of protic ionic liquids: Comparison with aprotic ionic liquids  

SciTech Connect

The stabilization energies for the formation (E{sub form}) of 11 ion pairs of protic and aprotic ionic liquids were studied by MP2/6-311G{sup **} level ab initio calculations to elucidate the difference between the interactions of ions in protic ionic liquids and those in aprotic ionic liquids. The interactions in the ion pairs of protic ionic liquids (diethylmethylammonium [dema] and dimethylpropylammonium [dmpa] based ionic liquids) are stronger than those of aprotic ionic liquids (ethyltrimethylammonium [etma] based ionic liquids). The E{sub form} for the [dema][CF{sub 3}SO{sub 3}] and [dmpa][CF{sub 3}SO{sub 3}] complexes (?95.6 and ?96.4 kcal/mol, respectively) are significantly larger (more negative) than that for the [etma][CF{sub 3}SO{sub 3}] complex (?81.0 kcal/mol). The same trend was observed for the calculations of ion pairs of the three cations with the Cl{sup ?}, BF{sub 4}{sup ?}, TFSA{sup ?} anions. The anion has contact with the N–H bond of the dema{sup +} or dmpa{sup +} cations in the most stable geometries of the dema{sup +} and dmpa{sup +} complexes. The optimized geometries, in which the anions locate on the counter side of the cations, are 11.0–18.0 kcal/mol less stable, which shows that the interactions in the ions pairs of protic ionic liquids have strong directionality. The E{sub form} for the less stable geometries for the dema{sup +} and dmpa{sup +} complexes are close to those for the most stable etma{sup +} complexes. The electrostatic interaction, which is the major source of the attraction in the ion pairs, is responsible for the directionality of the interactions and determining the magnitude of the interaction energy. Molecular dynamic simulations of the [dema][TFSA] and [dmpa][TFSA] ionic liquids show that the N–H bonds of the cations have contact with the negatively charged (oxygen and nitrogen) atoms of TFSA{sup ?} anion, while the strong directionality of the interactions was not suggested from the simulation of the [etma][CF{sub 3}SO{sub 3}] ionic liquid.

Tsuzuki, Seiji, E-mail: s.tsuzuki@aist.go.jp [Research Initiative of Computational Sciences (RICS), Nanosystem Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan)] [Research Initiative of Computational Sciences (RICS), Nanosystem Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan); Shinoda, Wataru [Health Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577 (Japan)] [Health Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577 (Japan); Miran, Md. Shah; Kinoshita, Hiroshi; Yasuda, Tomohiro; Watanabe, Masayoshi [Department of Chemistry and Biotechnology, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501 (Japan)] [Department of Chemistry and Biotechnology, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501 (Japan)

2013-11-07

2

Pronounced structure in confined aprotic room-temperature ionic liquids.  

PubMed

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

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

2009-05-21

3

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

Microsoft Academic Search

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

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

2006-01-01

4

Spectroscopic determination of relative Brønsted acidity as a predictor of reactivity in aprotic ionic liquids.  

PubMed

A simple titration technique utilizing pyridine as a FTIR spectroscopy probe is demonstrated to successfully predict relative Brønsted acid-limited reaction rates in different ionic liquid (IL) environments. Relative acidity is shown to vary across three aprotic ILs in a manner that is specific to the particular acid-IL pairing. PMID:25784279

Horowitz, Ariel I; Arias, Paola; Panzer, Matthew J

2015-03-31

5

Non-ionogenic amphiphiles in aprotic ionic liquids  

NASA Astrophysics Data System (ADS)

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.

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

2015-04-01

6

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

PubMed

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

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

2014-08-01

7

(Eco)toxicity and biodegradability of selected protic and aprotic ionic liquids.  

PubMed

Ionic liquids (ILs) are a promising group of compounds with a large variety of possible structures and uses. They are considered as a potential "green" replacement for traditional volatile organic solvents, but their impact on the environment is often neglected or not studied enough. In the present study, selected representatives of two ILs groups were analyzed: a new family of protic ILs (derived from aliphatic amines and organic acids) and some frequently used aprotic ILs (substituted imidazolium and piridinium chlorides). The aquatic toxicity (test organisms Vibrio fischeri, Pseudokirchneriella subcapitata and Lemna minor) and biodegradability tests were carried out. The additional tests with enzyme (acetylcholinesterase) and leukemia rat cells (IPC-81) provided more in-depth evaluation of toxicity. In our comparative hazard assessment protic ILs have EC50 values >100 mg L(-1) in all of the tests performed, except in the case of three representatives toward Lemna minor. They also show good biodegradability rates. The EC50 values for aprotic ILs are various orders of magnitude lower than the ones for protic ILs in most of the tests and they show a lower biodegradability potential. These findings indicate that protic ILs can be considered as environmentally safer alternatives for more toxic ILs and organic solvents. PMID:23912075

Peric, Brezana; Sierra, Jordi; Martí, Esther; Cruañas, Robert; Garau, Maria Antonia; Arning, Jürgen; Bottin-Weber, Ulrike; Stolte, Stefan

2013-10-15

8

Elucidating Interactions and Conductivity of Newly Synthesised Low Bandgap Polymer with Protic and Aprotic Ionic Liquids  

PubMed Central

In this paper, we have examined the conductivity and interaction studies of ammonium and imidazolium based ionic liquids (ILs) with the newly synthesised low bandgap polymer (Poly(2-heptadecyl-4-vinylthieno[3,4-d]thiazole) (PHVTT)). Use of low bandgap polymers is the most suitable way to harvest a broader spectrum of solar radiations for solar cells. But, still there is lack of most efficient low bandgap polymer. In order to solve this problem, we have synthesised a new low bandgap polymer and investigated its interaction with the ILs to enhance its conductivity. ILs may undergo almost unlimited structural variations; these structural variations have attracted extensive attention in polymer studies. The aim of present work is to illustrate the state of art progress of implementing the interaction of ILs (protic and aprotic ILs) with newly synthesised low bandgap polymer. In addition to this, our UV-Vis spectroscopy, confocal Raman spectroscopy and FT-IR spectroscopy results have revealed that all studied ILs (tributylmethylammonium methyl sulfate ([N1444][MeSO4] from ammonium family) and 1-methylimidazolium chloride ([Mim]Cl, and 1-butyl-3-methylimidazolium chloride ([Bmim]Cl from imidazolium family) have potential to interact with polymer. Our semi empirical calculation with help of Hyperchem 7 shows that protic IL ([Mim]Cl) interacts strongly with the low bandgap polymer through the H-bonding. Further, protic ILs shows enhanced conductivity than aprotic ILs in association with low bandgap polymer. This study provides the combined effect of low bandgap polymer and ILs that may generate many theoretical and experimental opportunities. PMID:23874829

Attri, Pankaj; Lee, Seung-Hyun; Hwang, Sun Woo; Kim, Joong I. L.; Lee, Sang Woo; Kwon, Gi-Chung; Choi, Eun Ha; Kim, In Tae

2013-01-01

9

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

SciTech Connect

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.

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

2013-06-01

10

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)

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.

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

2012-09-01

11

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

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

Yaghini, N; Nordstierna, L; Martinelli, A

2014-05-28

12

High voltage supercapacitors based on carbon-grafted NiO nanowires interfaced with an aprotic ionic liquid.  

PubMed

The report provides a preliminary assessment of the charge storage prerogatives of an asymmetric electrochemical capacitor employing a carbon-grafted NiO electrode interfaced with 1-ethyl-3-methyl imidazoliumdicyanamide as an ionic liquid electrolyte. This configuration has been demonstrated to be potentially exploited for developing hybrid supercapacitors providing as high energy density as 21 W h Kg(-1). PMID:25742721

Paravannoor, Anjali; Nair, Shantikumar V; Pattathil, Praveen; Manca, Michele; Balakrishnan, Avinash

2015-03-24

13

Electrochemical response in aprotic ionic liquid electrolytes of TiO2 anatase anodes based on mesoporous mesocrystals with uniform colloidal size  

NASA Astrophysics Data System (ADS)

Mesocrystals (superstructures of crystallographically-oriented inorganic nanocrystals) represent sophisticated configurations generated from biomineralization processes, and an example of nonclassical crystallization mechanisms. Being the closest relatives to single-crystals at the nanoscale, porous mesocrystals are considered as ideal configurations to improve functional properties, and to correlate structural and textural features with materials functionality. Here we show that TiO2 anatase mesoporous colloidal mesocrystals, synthesized by a self-assembly/seeding method, can be easily processed as active materials in anode composites. These anode composites can be efficiently infiltrated during battery operation with safe aprotic ionic liquid electrolytes down to the mesoporosity of mesocrystals (3-4 nm), and operate over a wider temperature window than organic carbonates. For example, after continuous galvanostatic cycling for 1 month at high temperatures (15 days at 60 °C + 15 days at 80 °C, ?130 cycles), these anode composites sustain a capacity at 67 mA g-1 that is still remarkable for TiO2-based anodes (155 mAh g-1 or 200 mAh cm-3, coulombic efficiency of ?99%). On contrast, in organic carbonates the capacity decays down to 80 mAh g-1 after only 15 days at 60 °C. Our results suggest that the principles derived from porous anatase mesocrystal/ionic liquid electrolyte combinations could constitute the basis for battery applications in which safety, durability and variability in operating temperature represent the primary concerns.

Amarilla, Jose Manuel; Morales, Enrique; Sanz, Jesus; Sobrados, Isabel; Tartaj, Pedro

2015-01-01

14

Are alkyl sulfate-based protic and aprotic ionic liquids stable with water and alcohols? A thermodynamic approach.  

PubMed

The knowledge of the chemical stability as a function of the temperature of ionic liquids (ILs) in the presence of other molecules such as water is crucial prior to developing any industrial application and process involving these novel materials. Fluid phase equilibria and density over a large range of temperature and composition can give basic information on IL purity and chemical stability. The IL scientific community requires accurate measurements accessed from reference data. In this work, the stability of different alkyl sulfate-based ILs in the presence of water and various alcohols (methanol, ethanol, 1-butanol, and 1-octanol) was investigated to understand their stability as a function of temperature up to 423.15 K over the hydrolysis and transesterification reactions, respectively. From this investigation, it was clear that methyl sulfate- and ethyl sulfate-based ILs are not stable in the presence of water, since hydrolysis of the methyl sulfate or ethyl sulfate anions to methanol or ethanol and hydrogenate anion is undoubtedly observed. Such observations could help to explain the differences observed for the physical properties published in the literature by various groups. Furthermore, it appears that a thermodynamic equilibrium process drives these hydrolysis reactions. In other words, these hydrolysis reactions are in fact reversible, providing the possibility to re-form the desired alkyl sulfate anions by a simple transesterification reaction between hydrogen sulfate-based ILs and the corresponding alcohol (methanol or ethanol). Additionally, butyl sulfate- and octyl sulfate-based ILs appear to follow this pattern but under more drastic conditions. In these systems, hydrolysis is observed in both cases after several months for temperatures up to 423 K in the presence of water. Therein, the partial miscibility of hydrogen sulfate-based ILs with long chain alcohols (1-butanol and 1-octanol) can help to explain the enhanced hydrolytic stability of the butyl sulfate- and octyl sulfate-based ILs compared with the methyl or ethyl sulfate systems. Additionally, rapid transesterification reactions are observed during liquid-liquid equilibrium studies as a function of temperature for binary systems of (hydrogen sulfate-based ionic liquids + 1-butanol) and of (hydrogen sulfate-based ionic liquids + 1-octanol). Finally, this atom-efficient catalyst-free transesterification reaction between hydrogen sulfate-based ILs and alcohol was then tested to provide a novel way to synthesize new ILs with various anion structures containing the alkyl sulfate group. PMID:23320846

Jacquemin, Johan; Goodrich, Peter; Jiang, Wei; Rooney, David W; Hardacre, Christopher

2013-02-14

15

Electrochemical Generation of Superoxide in Room-Temperature Ionic Liquids  

E-print Network

Electrochemical Generation of Superoxide in Room-Temperature Ionic Liquids Inas M. Al demonstrated that superoxide ion can be generated electrochemically in room-temperature ionic-liquid solvents aprotic solvents such as dimethyl formamide and acetonitrile. However, ionic liquids are nonvolatile

Weidner, John W.

16

Ionic Liquids  

Microsoft Academic Search

Ionic liquids are receiving an upsurge of interest as green solvents; primarily as replacements for conventional media in\\u000a chemical processes. This review presents an overview of the chemistry that has been developed utilising ionic liquids as either\\u000a catalyst and\\/or solvent, with particular emphasis on processes that have been taken beyond the pre-competetive laboratory\\u000a stage and represent clean industrial technology with

J. D. Holbrey; K. R. Seddon

1999-01-01

17

The synthesis and electrochemical characterization of bis(fluorosulfonyl)imide-based protic ionic liquids.  

PubMed

A protic ionic liquid containing the FSI anion has been synthesized for the first time and used as an electrolyte in an electrochemical storage device. This PIL-based electrolyte outperforms commonly used aprotic ionic liquids, maintaining the advantages and safety of ionic liquid-based electrolytes. PMID:25645883

Menne, S; Vogl, T; Balducci, A

2015-02-28

18

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.

19

Hydrogen bonding in ionic liquids.  

PubMed

Ionic liquids (IL) and hydrogen bonding (H-bonding) are two diverse fields for which there is a developing recognition of significant overlap. Doubly ionic H-bonds occur when a H-bond forms between a cation and anion, and are a key feature of ILs. Doubly ionic H-bonds represent a wide area of H-bonding which has yet to be fully recognised, characterised or explored. H-bonds in ILs (both protic and aprotic) are bifurcated and chelating, and unlike many molecular liquids a significant variety of distinct H-bonds are formed between different types and numbers of donor and acceptor sites within a given IL. Traditional more neutral H-bonds can also be formed in functionalised ILs, adding a further level of complexity. Ab initio computed parameters; association energies, partial charges, density descriptors as encompassed by the QTAIM methodology (?BCP), qualitative molecular orbital theory and NBO analysis provide established and robust mechanisms for understanding and interpreting traditional neutral and ionic H-bonds. In this review the applicability and extension of these parameters to describe and quantify the doubly ionic H-bond has been explored. Estimating the H-bonding energy is difficult because at a fundamental level the H-bond and ionic interaction are coupled. The NBO and QTAIM methodologies, unlike the total energy, are local descriptors and therefore can be used to directly compare neutral, ionic and doubly ionic H-bonds. The charged nature of the ions influences the ionic characteristics of the H-bond and vice versa, in addition the close association of the ions leads to enhanced orbital overlap and covalent contributions. The charge on the ions raises the energy of the Ylp and lowers the energy of the X-H ?* NBOs resulting in greater charge transfer, strengthening the H-bond. Using this range of parameters and comparing doubly ionic H-bonds to more traditional neutral and ionic H-bonds it is clear that doubly ionic H-bonds cover the full range of weak through to very strong H-bonds. PMID:25582457

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

2015-02-23

20

Ionic liquids as electrolytes  

Microsoft Academic Search

Salts having a low melting point are liquid at room temperature, or even below, and form a new class of liquids usually called room temperature ionic liquids (RTIL). Information about RTILs can be found in the literature with such key words as: room temperature molten salt, low-temperature molten salt, ambient-temperature molten salt, liquid organic salt or simply ionic liquid. Their

Maciej Gali?ski; Andrzej Lewandowski; Izabela St?pniak

2006-01-01

21

The distillation and volatility of ionic liquids  

NASA Astrophysics Data System (ADS)

It is widely believed that a defining characteristic of ionic liquids (or low-temperature molten salts) is that they exert no measurable vapour pressure, and hence cannot be distilled. Here we demonstrate that this is unfounded, and that many ionic liquids can be distilled at low pressure without decomposition. Ionic liquids represent matter solely composed of ions, and so are perceived as non-volatile substances. During the last decade, interest in the field of ionic liquids has burgeoned, producing a wealth of intellectual and technological challenges and opportunities for the production of new chemical and extractive processes, fuel cells and batteries, and new composite materials. Much of this potential is underpinned by their presumed involatility. This characteristic, however, can severely restrict the attainability of high purity levels for ionic liquids (when they contain poorly volatile components) in recycling schemes, as well as excluding their use in gas-phase processes. We anticipate that our demonstration that some selected families of commonly used aprotic ionic liquids can be distilled at 200-300°C and low pressure, with concomitant recovery of significant amounts of pure substance, will permit these currently excluded applications to be realized.

Earle, Martyn J.; Esperança, José M. S. S.; Gilea, Manuela A.; Canongia Lopes, José N.; Rebelo, Luís P. N.; Magee, Joseph W.; Seddon, Kenneth R.; Widegren, Jason A.

2006-02-01

22

Ionic liquids in catalysis  

Microsoft Academic Search

The current state of the art of the application of ionic liquids in catalysis is reviewed. The review selects examples of the different ways in which ionic liquids have been applied in catalysis, i.e. as the catalyst itself, as a co-catalyst or catalyst activator, as the source of a new ligand for a catalytic metal centre, or just as the

Tom Welton

2004-01-01

23

For session on "Structure and Properties of Ionic Liquids and Molten Salts" Ionic Liquids, quasi-ionic liquids, and quasi-liquid ionics, all with high  

E-print Network

For session on "Structure and Properties of Ionic Liquids and Molten Salts" Ionic Liquids, quasi-ionic liquids, and quasi-liquid ionics, all with high ionic liquids are prepared by proton transfer from a Bronsted acid

Angell, C. Austen

24

Biocatalytic transformations in ionic liquids  

Microsoft Academic Search

Room temperature ionic liquids are non-volatile, thermally stable and highly polar; they are also moderately hydrophilic solvents. Here, we discuss their use as reaction media for biocatalysis. Enzymes of widely diverging types are catalytically active in ionic liquids or aqueous biphasic ionic liquid systems. Lipases, in particular, maintain their activity in anhydrous ionic liquid media; the (enantio)selectivity and operational stability

Fred van Rantwijk; Rute Madeira Lau; Roger A Sheldon

2003-01-01

25

Photochemistry in Ionic Liquids  

Microsoft Academic Search

\\u000a The use of ionic liquids in applications such as electrochemistry [1], organic synthesis [2, 3], and separation science [4] is fast becoming a mature area of study, and many data have now been accumulated. In contrast, study of the physical properties\\u000a of ionic liquids has lagged behind the advances made in these more applied areas of chemistry. To this end,

Charles M. Gordon

26

Applications of ionic liquids.  

PubMed

Ionic liquids have recently gained popularity in the scientific community owing to their special properties and characteristics. One of the reasons why ionic liquids have been termed "green solvents" is due to their negligible vapour pressure. Their use in electrochemical, biological and metal extraction applications is discussed. Wide research has been carried out for their use in batteries, solar panels, fuel cells, drug deliveries and biomass pretreatments. This work aims to consolidate the various findings from previous works in these areas. PMID:22711528

Patel, Divia Dinesh; Lee, Jong-Min

2012-06-01

27

Synthesis of ionic liquids  

DOEpatents

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.

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

2011-11-01

28

Synthesis of ionic liquids  

DOEpatents

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

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

2008-09-09

29

Ionic liquids as novel solvents for ionic polymer transducers  

Microsoft Academic Search

The use of ionic liquids as solvents for ionic polymer (specifically, Nafion) transducers is demonstrated. Ionic liquids are attractive for this application because of their high inherent stability. Ionic liquids are salts that exist as liquids at room temperature and have no measureable vapor pressure. Therefore, the use of ionic liquids as solvents for ionic polymer transducers can eliminate the

Matthew D. Bennett; Donald J. Leo

2004-01-01

30

Chemical propulsion using ionic liquids.  

PubMed

Chemical propulsion generates motion by directly converting locally stored chemical energy into mechanical energy. Here, we describe chemically driven autonomous motion generated by using imidazolium-based ionic liquids on a water surface. From measurements of the driving force of a locomotor loaded with an ionic liquid and observations of convection on the water surface originating from the ionic liquid container of the locomotor, the driving mechanism of the motion is found to be due to the Marangoni effect that arises from the anisotropic distribution of ionic liquids on the water surface. The maximum driving force and the force-generation duration are determined by the surface activity of the ionic liquid and the solubility of the ionic liquid in water, respectively. Because of the special properties of ionic liquids, a chemical locomotor driven by ionic liquids is promising for realizing autonomous micromachines and nanomachines that are safe and environmentally friendly. PMID:23398242

Tsuchitani, Shigeki; Takagi, Nobuhiro; Kikuchi, Kunitomo; Miki, Hirobumi

2013-03-01

31

Task-specific ionic liquids.  

PubMed

In recent years, ionic liquids have attracted the attention of many chemists as a result of their unique properties as solvents for chemical transformations. The focus of this Minireview is on applications of so-called "task-specific" ionic liquids, whereby the role of the ionic liquid goes beyond that of a solvent. Such ionic liquids find application in a wide range of areas, including catalysis, synthesis, gas absorption, and analysis. PMID:20229544

Giernoth, Ralf

2010-04-01

32

Enzyme catalysis in ionic liquids  

Microsoft Academic Search

Ionic liquids offer new possibilities for the application of solvent engineering to biocatalytic reactions. Although in many cases ionic liquids have simply been used to replace organic solvents, they have often led to improved process performance. Unlike conventional organic solvents, ionic liquids possess no vapor pressure, are able to dissolve many compounds, and can be used to form two-phase systems

Udo Kragl; Marrit Eckstein; Nicole Kaftzik

2002-01-01

33

3-Methylpiperidinium ionic liquids.  

PubMed

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

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

2015-04-01

34

Properties of ionic liquid solvents for catalysis  

Microsoft Academic Search

Ionic liquids are good solvents for catalytic reactions. The rational selection of the appropriate ionic liquid solvent for a particular reaction requires general knowledge of the properties of ionic liquids, and the details of some properties of the specific ionic liquid solvents being considered. The solvent properties of ionic liquids that are relevant to catalysis are discussed, and sources of

John S Wilkes

2004-01-01

35

Electrokinetic Transport in Ionic Liquids  

E-print Network

A key difficulty in understanding electrokinetic transport in ionic liquids lies in the construction of an appropriate reference dynamics. The common assumption of modelling ion dynamics as a Langevin process is not warranted for solvent-free ionic liquids. The electrokinetic transport of ionic liquids obtained by coarse graining a simple exclusion process defined on a lattice is considered. The resulting dynamical equations can be written as a gradient flow with a degenerate mobility function. This form of the mobility function gives rise to charging behaviours that are different to the ones known in electrolytic solutions; the predicted behaviours agree qualitatively with the phenomenology observed in simulations.

Lee, Alpha A; Goriely, Alain

2015-01-01

36

Electrokinetic Transport in Ionic Liquids  

E-print Network

A key difficulty in understanding electrokinetic transport in ionic liquids lies in the construction of an appropriate reference dynamics. The common assumption of modelling ion dynamics as a Langevin process is not warranted for solvent-free ionic liquids. The electrokinetic transport of ionic liquids obtained by coarse graining a simple exclusion process defined on a lattice is considered. The resulting dynamical equations can be written as a gradient flow with a degenerate mobility function. This form of the mobility function gives rise to charging behaviours that are different to the ones known in electrolytic solutions; the predicted behaviours agree qualitatively with the phenomenology observed in simulations.

Alpha A. Lee; Dominic Vella; Alain Goriely

2015-02-13

37

Ionic Liquids in Chemical Analysis  

Microsoft Academic Search

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,

Mihkel Koel

2005-01-01

38

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

SciTech Connect

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.

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

2014-01-01

39

Ionic Liquid Epoxy Resin Monomers  

NASA Technical Reports Server (NTRS)

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.

Paley, Mark S. (Inventor)

2013-01-01

40

Ionic liquids: applications in catalysis  

Microsoft Academic Search

The use of room temperature ionic liquids as either solvents or catalysts has been the subject of considerable recent attention because of the prospects for “green” catalysis. This paper presents a review of the potential applications of these unique liquid materials in industrial catalysis.

Dongbin Zhao; Min Wu; Yuan Kou; Enze Min

2002-01-01

41

Glyme-lithium salt equimolar molten mixtures: concentrated solutions or solvate ionic liquids?  

PubMed

To demonstrate a new family of ionic liquids (ILs), i.e., "solvate" ionic liquids, the properties (thermal, transport, and electrochemical properties, Lewis basicity, and ionicity) of equimolar molten mixtures of glymes (triglyme (G3) and tetraglyme (G4)) and nine different lithium salts (LiX) were investigated. By exploring the anion-dependent properties and comparing them with the reported data on common aprotic ILs, two different classes of liquid regimes, i.e., ordinary concentrated solutions and "solvate" ILs, were found in the glyme-Li salt equimolar mixtures ([Li(glyme)]X) depending on the anionic structures. The class a given [Li(glyme)]X belonged to was governed by competitive interactions between the glymes and Li cations and between the counteranions (X) and Li cations. [Li(glyme)]X with weakly Lewis basic anions can form long-lived [Li(glyme)](+) complex cations. Thus, they behaved as typical ionic liquids. The lithium "solvate" ILs based on [Li(glyme)]X have many desirable properties for lithium-conducting electrolytes, including high ionicity, a high lithium transference number, high Li cation concentration, and high oxidative stability, in addition to the common properties of ionic liquids. The concept of "solvate" ionic liquids can be utilized in an unlimited number of combinations of other metal salts and ligands, and will thus open a new field of research on ionic liquids. PMID:22897246

Ueno, Kazuhide; Yoshida, Kazuki; Tsuchiya, Mizuho; Tachikawa, Naoki; Dokko, Kaoru; Watanabe, Masayoshi

2012-09-13

42

Ionic liquids as oxidic media for electron transfer studies  

NASA Astrophysics Data System (ADS)

We review the basic ideas underlying the electron free energy level diagrams that have been found useful in considering the thermodynamics of redox processes in molten silicates and related high temperature ionic liquid (IL) solvents, and then show how closely they link to behavior observable in ambient temperature ionic liquids. Much of the information available on redox levels in molten oxides has been gleaned from chemical analysis and spectroscopic species distribution studies, but it is simpler to obtain the data electrochemically. Here, we report some cyclic voltammetry measurements of the Fe(II)/Fe(III) redox equilibrium in aprotic ionic liquids whose anions provide oxide environments for the redox species that are of different electronic polarizability character from the high temperature solvents, and relate the observations to those of the earlier studies. Quasi-reversible behavior is found in each of the cases studied. As might be expected, the Fe(II)/Fe(III) equilibrium experiences a more basic environment in an acetate IL than it experiences in any of the common glassforming oxide media, while triflate anions contrast by providing a more acid environment than does the most acid of the molten oxide glassformers studied (an alkali phosphate). The difference can amount to well over 1 V, suggesting the possibility of a "basicity cell" where the same redox couple locates in anode and cathode compartments of the cell, and only the anion environment is different.

Ueno, Kazuhide; Angell, C. Austen

2012-06-01

43

Externally Wetted Ionic Liquid Thruster  

NASA Astrophysics Data System (ADS)

This paper presents initial developments of an electric propulsion system based on ionic liquid ion sources (ILIS). Propellants are ionic liquids, which are organic salts with two important characteristics; they remain in the liquid state at room temperature and have negligible vapor pressure, thus allowing their use in vacuum. The working principles of ILIS are similar to those of liquid metal ion sources (LMIS), in which a Taylor cone is electrostatically formed at the tip of an externally wetted needle while ions are emitted directly from its apex. ILIS have the advantage of being able to produce negative ions that have similar masses than their positive counterparts with similar current levels. This opens up the possibility of achieving plume electrical neutrality without electron emitters. The possible multiplexing of these emitters is discussed in terms of achievable thrust density for applications other than micro-propulsion.

Lozano, P.; Martinez-Sanchez, M.; Lopez-Urdiales, J. M.

2004-10-01

44

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

Microsoft Academic Search

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

Matthew D. Green; Timothy E. Long

2009-01-01

45

The distillation and volatility of ionic liquids  

Microsoft Academic Search

It is widely believed that a defining characteristic of ionic liquids (or low-temperature molten salts) is that they exert no measurable vapour pressure, and hence cannot be distilled. Here we demonstrate that this is unfounded, and that many ionic liquids can be distilled at low pressure without decomposition. Ionic liquids represent matter solely composed of ions, and so are perceived

Martyn J. Earle; José M. S. S. Esperança; Manuela A. Gilea; José N. Canongia Lopes; Luís P. N. Rebelo; Joseph W. Magee; Kenneth R. Seddon; Jason A. Widegren

2006-01-01

46

Ionic liquids: Green solvents for nonaqueous biocatalysis  

Microsoft Academic Search

Ionic liquids hold potential as green solvents because of their lack of vapour pressure, and are opening up a burgeoningly new field of nonaqueous enzymology. As compared to those observed in conventional organic solvents, enzymes in ionic liquids have presented enhanced activity, stability, and selectivity. Advantages of using ionic liquids over the use of normal organic solvents as reaction medium

Zhen Yang; Wubin Pan

2005-01-01

47

Application of Ionic Liquids in Liquid Chromatography  

Microsoft Academic Search

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

Micha? Piotr Marsza??; Roman Kaliszan

2007-01-01

48

Ionic Liquids in Biomass Processing  

Microsoft Academic Search

\\u000a Ionic liquids have been studied for their special solvent properties in a wide range of processes, including reactions involving\\u000a carbohydrates such as cellulose and glucose. Biomass is a widely available and renewable resource that is likely to become\\u000a an economically viable source of starting materials for chemical and fuel production, especially with the price of petroleum\\u000a set to increase as

Suzie Tan; Douglas MacFarlane

49

Application of Ionic Liquids in Hydrometallurgy  

PubMed Central

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

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

2014-01-01

50

Application of ionic liquids in hydrometallurgy.  

PubMed

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

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

2014-01-01

51

Radiation Chemistry and Photochemistry of Ionic Liquids  

SciTech Connect

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.

Wishart, J.F.; Takahaski, K.

2010-12-01

52

Amphiphilic and phase-separable ionic liquids for biomass processing.  

PubMed

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

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

2014-05-01

53

Ionic Liquids to Replace Hydrazine  

NASA Technical Reports Server (NTRS)

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.

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

2011-01-01

54

Ionic liquids for rechargeable lithium batteries  

Microsoft Academic Search

We have investigated possible anticipated advantages of ionic-liquid electrolytes for use in lithium-ion batteries. Thermal stabilities and phase behavior were studied by thermal gravimetric analysis and differential scanning calorimetry. The ionic liquids studied include various imidazoliumTFSI systems, pyrrolidiniumTFSI, BMIMPF, BMIMBF, and BMIMTf. Thermal stabilities were measured for neat ionic liquids and for BMIMBF-LiBF, BMIMTf-LiTf, BMIMTFSI-LiTFSI mixtures. Conductivities have been measured

Justin Salminen; Nicolas Papaiconomou; John Kerr; John Prausnitz; John Newman

2005-01-01

55

Dissolution of Wood in Ionic Liquids  

Microsoft Academic Search

The present paper demonstrates that both hardwoods and softwoods are readily soluble in various imidazolium-based ionic liquids (ILs) under gentle conditions. More specifically, a variety of ionic liquids can only partially dissolve wood chips, whereas ionic liquids such as 1-butyl-3-methylimida- zolium chloride and 1-allyl-3-methylimidazolium chloride have good solvating power for Norway spruce sawdust and Norway spruce and Southern pine thermomechanical

Ilkka Kilpeläinen; Haibo Xie; Alistair King; Mari Granstrom; Sami Heikkinen; Dimitris S. Argyropoulos

2007-01-01

56

Early Events in Ionic Liquid Radiation Chemistry  

SciTech Connect

Ionic liquids are interesting and useful materials whose solvation time scales are up to thousands of times longer than in conventional solvents. The extended lifetimes of pre-solvated electrons and other energetic species in ionic liquids has profound consequences for the radiolytic product distributions and reactivity patterns. We use a newly developed, multiplexed variation of pulse-probe spectroscopy to measure the kinetics of the early dynamical and reactive events in ionic liquids.

Wishart, J.F.; Cook, A.; Rimmer, R.D.; Gohdo, M.

2010-09-14

57

New ionic liquids as innovative reaction media  

NASA Astrophysics Data System (ADS)

New ionic liquids were developed based on triazolium salts and guanidinium salts. By introduction of functions, such as organocatalytic units, into these units task-specific ionic liquids could be obtained. These products can be used as efficient catalysts in asymmetric syntheses.

Liebscher, J.; Shah, J.; Yacob, Z.; Sadiq, S.; Hanelt, S.; Blumenthal, H.

2009-08-01

58

Phosphonium salt ionic liquids in organic synthesis  

Microsoft Academic Search

A survey of substitution reactions conducted in a phosphonium bistriflimide ionic liquid is presented. The results demonstrate high selectivity favoring substitution over typically competitive elimination and solvolytic processes even when challenging secondary and tertiary electrophiles are employed. The first reports of Kornblum substitution reactions in an ionic liquid are described that proceed with very high chemoselectivity in favor of nitro

Sreedhar Cheekoori

2008-01-01

59

Chiral discrimination by ionic liquids: impact of ionic solutes.  

PubMed

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. Chirality 27:320-325, 2015. © 2015 Wiley Periodicals, Inc. PMID:25727925

Brown, Christopher J; Hopkins, Todd A

2015-04-01

60

Ionic liquid incorporating thiosalicylate for metal removal  

NASA Astrophysics Data System (ADS)

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

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

2012-09-01

61

Mixtures of protic ionic liquids and propylene carbonate as advanced electrolytes for lithium-ion batteries.  

PubMed

In this study we investigated the chemical-physical properties of mixtures containing the protic ionic liquid (PIL) N-butyl-pyrrolidinium bis(trifluoromethanesulfonyl)imide (PYRH4TFSI), propylene carbonate (PC) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in view of their use as electrolytes for lithium-ion batteries (LIBs). We showed that these electrolytic solutions might display conductivity and viscosity comparable to those of conventional electrolytes. Depending on the amount of PIL present inside the mixtures, such mixtures might also display the ability to suppress the anodic dissolution of Al. Furthermore, we showed that the coordination of lithium ions by TFSI in PIL-PC mixtures appears to be different than the one observed for mixtures of PC and aprotic ionic liquids (AILs). When used in combination with a battery electrode, e.g. lithium iron phosphate (LFP), these mixtures allow the achievement of high performance also at a very high C-rate. PMID:25328075

Vogl, T; Menne, S; Balducci, A

2014-12-01

62

Actinide chemistry in ionic liquids.  

PubMed

This Forum Article provides an overview of the reported studies on the actinide chemistry in ionic liquids (ILs) with a particular focus on several fundamental chemical aspects: (i) complex formation, (ii) electrochemistry, and (iii) extraction behavior. The majority of investigations have been dedicated to uranium, especially for the 6+ oxidation state (UO2(2+)), because the chemistry of uranium in ordinary solvents has been well investigated and uranium is the most abundant element in the actual nuclear fuel cycles. Other actinides such as thorium, neptunium, plutonium, americium, and curiumm, although less studied, are also of importance in fully understanding the nuclear fuel engineering process and the safe geological disposal of radioactive wastes. PMID:22873132

Takao, Koichiro; Bell, Thomas James; Ikeda, Yasuhisa

2013-04-01

63

Modeling Liquid-Liquid Equilibrium of Ionic Liquid Systems with NRTL, Electrolyte-NRTL, and UNIQUAC  

E-print Network

Modeling Liquid-Liquid Equilibrium of Ionic Liquid Systems with NRTL, Electrolyte-NRTL, and UNIQUAC: markst@nd.edu #12;Abstract Characterization of liquid-liquid equilibrium (LLE) in system containing ionic; Ionic liquids; Octanol-water partition coefficients; Excess Gibbs energy models; Electrolyte models #12

Stadtherr, Mark A.

64

Structure of Ionic Liquids The Structure of a Room-Temperature Ionic  

E-print Network

Structure of Ionic Liquids The Structure of a Room-Temperature Ionic Liquid with and without Trace Tetrafluoroborate** Andrea Mele,* Chieu D. Tran, and Silvia H. De Paoli Lacerda Room temperature ionic liquids of a given cross peak in 1a (pure ionic liquid) and V=integrated volume of the same cross peak in the sample

Reid, Scott A.

65

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

PubMed Central

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

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

2014-01-01

66

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

PubMed

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

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

2014-01-01

67

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

NASA Astrophysics Data System (ADS)

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.

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

2014-02-01

68

Ionic Liquids as Extracting Agents for Heavy Metals  

Microsoft Academic Search

The development of applications of ionic liquids in extraction processes stretches back to the mid-1960s when the first studies on ionic liquid- based extractions were published. Since then, the interest of both academics and the industrial community on the development of ionic liquids-based technologies is continuously growing. The main driving force of ionic liquid engineering is to combine their “environmentally

Anja Stojanovic; Bernhard K. Keppler

2012-01-01

69

Friedel-Crafts Acylation of Aromatic Compounds in Ionic Liquids  

Microsoft Academic Search

This article first reviews the application of ionic liquids in Friedel-Crafts acylation reactions. Ionic liquids can be used as catalyst solvents, the active component on solid carriers, or just as the solvent. One advantage of using ionic liquids in acylation reactions is the enhanced reaction rates, conversion, and selectivity. The acylation mechanisms of aromatic compounds in ionic liquids are also

Z. C. Liu; X. H. Meng; R. Zhang; C. M. Xu

2009-01-01

70

Ionic liquid polyoxometalates as light emitting materials  

SciTech Connect

The low melting point, negligible vapor pressure, good solubility, and thermal and chemical stability make ionic liquids useful materials for a wide variety of applications. Polyoxometalates are early transition metal oxygen clusters that can be synthesized in many different sizes and with a variety of heterometals. The most attractive feature of POMs is that their physical properties, in particular electrical, magnetic, and optical properties, can be easily modified following known procedures. It has been shown that POMs can exhibit cooperative properties, as superconductivity and energy transfer. POM ionic liquids can be obtained by selecting the appropliate cation. Different alkyl ammonium and alkyl phosphonium salts are being used to produce new POM ionic liquids together with organic or inorganic luminescent centers to design light emitting materials. Ammonium and phosphonium cations with activated, polymerizable groups are being used to further polymerize the ionic liquid into transparent, solid materials with high metal density.

Ortiz-acosta, Denisse [Los Alamos National Laboratory; Del Sesto, Rico E [Los Alamos National Laboratory; Scott, Brian [Los Alamos National Laboratory; Bennett, Bryan L [Los Alamos National Laboratory; Purdy, Geraldine M [Los Alamos National Laboratory; Muenchausen, Ross E [Los Alamos National Laboratory; Mc Kigney, Edward [Los Alamos National Laboratory; Gilbertson, Robert [Los Alamos National Laboratory

2008-01-01

71

Are Room Temperature Ionic Liquids Dilute Electrolytes?  

E-print Network

An important question in understanding the structure of ionic liquids is whether ions are truly "free" and mobile which would correspond to a concentrated ionic melt, or are rather "bound" in ion pairs, that is a liquid of ion pairs with a small concentration of free ions. Recent surface force balance experiments from different groups have given conflicting answers to this question. We propose a simple model for the thermodynamics and kinetics of ion pairing in ionic liquids. Our model takes into account screened ion-ion, dipole-dipole and dipole-ion interactions in the mean field limit. The results of this model suggest that almost two thirds of the ions are free at any instant, and ion pairs have a short lifetime comparable to the characteristic timescale for diffusion. These results suggest that there is no particular thermodynamic or kinetic preference for ions residing in pairs. We therefore conclude that ionic liquids are concentrated, rather than dilute, electrolytes.

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

2014-01-01

72

Phosphonium-based ionic liquids and uses  

DOEpatents

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.

Del Sesto, Rico E; Koppisch, Andrew T; Lovejoy, Katherine S; Purdy, Geraldine M

2014-12-30

73

Are Room Temperature Ionic Liquids Dilute Electrolytes?  

E-print Network

An important question in understanding the structure of ionic liquids is whether ions are truly "free" and mobile which would correspond to a concentrated ionic melt, or are rather "bound" in ion pairs, that is a liquid of ion pairs with a small concentration of free ions. Recent surface force balance experiments from different groups have given conflicting answers to this question. We propose a simple model for the thermodynamics and kinetics of ion pairing in ionic liquids. Our model takes into account screened ion-ion, dipole-dipole and dipole-ion interactions in the mean field limit. The results of this model suggest that almost two thirds of the ions are free at any instant, and ion pairs have a short lifetime comparable to the characteristic timescale for diffusion. These results suggest that there is no particular thermodynamic or kinetic preference for ions residing in pairs. We therefore conclude that ionic liquids are concentrated, rather than dilute, electrolytes.

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

2014-12-26

74

IMPROVED SYNTHESIS OF ROOM TEMPERATURE IONIC LIQUIDS  

EPA Science Inventory

Room temperature ionic liquids (RTILs), molten salts comprised of N-alkylimidazolium cations and various anions, have received significant attention due to their commercial potential in a variety of chemical applications especially as substitutes for conventional volatile organic...

75

Superbase-derived protic ionic liquids  

DOEpatents

Protic ionic liquids having a composition of formula (A.sup.-)(BH.sup.+) wherein A.sup.- is a conjugate base of an acid HA, and BH.sup.+ is a conjugate acid of a superbase B. In particular embodiments, BH.sup.+ is selected from phosphazenium species and guanidinium species encompassed, respectively, by the general formulas: ##STR00001## The invention is also directed to films and membranes containing these protic ionic liquids, with particular application as proton exchange membranes for fuel cells.

Dai, Sheng; Luo, Huimin; Baker, Gary A.

2013-09-03

76

Ionic liquids in the synthesis of nanoobjects  

NASA Astrophysics Data System (ADS)

Data on the usage of the novel green solvents, ionic liquids, in the synthesis of nanoobjects and their stabilization are considered. The information is structured according to the resulting products of the synthetic processes: nanoparticles of noble metals, nanoparticles of non-metals, nanoparticles of metal oxides and chalcogenides, nanocomposites, and highly dispersed polymers. The conclusion is made that the ionic liquids might determine the structure and the properties of the nanoobjects, thus opening new fundamental and technological horizons in nanochemistry.

Tarasova, Natalia P.; Smetannikov, Yurii V.; Zanin, A. A.

2010-08-01

77

Enzymatic ester synthesis in ionic liquids  

Microsoft Academic Search

Six different ionic liquids based on dialkylimidazolium or quaternary ammonium cations associated with perfluorinated or bis(trifluoromethyl)sulfonyl amide anions were used as reaction media for ester synthesis catalyzed by both free Candida antarctica lipase B and ?-chymotrypsin at 2% (v\\/v) water content and 50°C. All the assayed ionic liquids proved adequate media for enzyme-catalyzed transesterification, and in the case of lipase,

Pedro Lozano; Teresa De Diego; Daniel Carrié; Michel Vaultier; José L Iborra

2003-01-01

78

Synthesis of esters in ionic liquids  

Microsoft Academic Search

Free Candida antarctica lipase B (CALB) was successfully applied to catalyzing the synthesis of alkyl esters by transesterification from vinyl esters and alcohols in ionic liquids based on 1-alkyl-3-methylimidazolium cations ([bmim+] and [omim+]) and the hexafluorophosphate anion ([PF6?]). First, the variables affecting the performance of CALB in transesterification reactions in ionic liquids, temperature and pH, were studied, choosing the synthesis

Antonia P. de los Ríos; Francisco J. Hernández-Fernández; F. Tomás-Alonso; Demetrio Gómez; Gloria Víllora

2008-01-01

79

Mixtures of protic ionic liquids and molecular cosolvents: a molecular dynamics simulation.  

PubMed

In this work, the effect of molecular cosolvents (water, ethanol, and methanol) on the structure of mixtures of these compounds with a protic ionic liquid (ethylammonium nitrate) is analyzed by means of classical molecular dynamics simulations. Included are as-yet-unreported measurements of the densities of these mixtures, used to test our parameterized potential. The evolution of the structure of the mixtures throughout the concentration range is reported by means of the calculation of coordination numbers and the fraction of hydrogen bonds in the system, together with radial and spatial distribution functions for the various molecular species and molecular ions in the mixture. The overall picture indicates a homogeneous mixing process of added cosolvent molecules, which progressively accommodate themselves in the network of hydrogen bonds of the protic ionic liquid, contrarily to what has been reported for their aprotic counterparts. Moreover, no water clustering similar to that in aprotic mixtures is detected in protic aqueous mixtures, but a somehow abrupt replacing of [NO3](-) anions in the first hydration shell of the polar heads of the ionic liquid cations is registered around 60% water molar concentration. The spatial distribution functions of water and alcohols differ in the coordination type, since water coordinates with [NO3](-) in a bidentate fashion in the equatorial plane of the anion, while alcohols do it in a monodentate fashion, competing for the oxygen atoms of the anion. Finally, the collision times of the different cosolvent molecules are also reported by calculating their velocity autocorrelation functions, and a caging effect is observed for water molecules but not in alcohol mixtures. PMID:24908021

Docampo-Álvarez, Borja; Gómez-González, Víctor; Méndez-Morales, Trinidad; Carrete, Jesús; Rodríguez, Julio R; Cabeza, Óscar; Gallego, Luis J; Varela, Luis M

2014-06-01

80

Mixtures of protic ionic liquids and molecular cosolvents: A molecular dynamics simulation  

NASA Astrophysics Data System (ADS)

In this work, the effect of molecular cosolvents (water, ethanol, and methanol) on the structure of mixtures of these compounds with a protic ionic liquid (ethylammonium nitrate) is analyzed by means of classical molecular dynamics simulations. Included are as-yet-unreported measurements of the densities of these mixtures, used to test our parameterized potential. The evolution of the structure of the mixtures throughout the concentration range is reported by means of the calculation of coordination numbers and the fraction of hydrogen bonds in the system, together with radial and spatial distribution functions for the various molecular species and molecular ions in the mixture. The overall picture indicates a homogeneous mixing process of added cosolvent molecules, which progressively accommodate themselves in the network of hydrogen bonds of the protic ionic liquid, contrarily to what has been reported for their aprotic counterparts. Moreover, no water clustering similar to that in aprotic mixtures is detected in protic aqueous mixtures, but a somehow abrupt replacing of [NO3]- anions in the first hydration shell of the polar heads of the ionic liquid cations is registered around 60% water molar concentration. The spatial distribution functions of water and alcohols differ in the coordination type, since water coordinates with [NO3]- in a bidentate fashion in the equatorial plane of the anion, while alcohols do it in a monodentate fashion, competing for the oxygen atoms of the anion. Finally, the collision times of the different cosolvent molecules are also reported by calculating their velocity autocorrelation functions, and a caging effect is observed for water molecules but not in alcohol mixtures.

Docampo-Álvarez, Borja; Gómez-González, Víctor; Méndez-Morales, Trinidad; Carrete, Jesús; Rodríguez, Julio R.; Cabeza, Óscar; Gallego, Luis J.; Varela, Luis M.

2014-06-01

81

Terpenes to Ionic Liquids: Synthesis and Characterization of Citronellal-Based Chiral Ionic Liquids  

Microsoft Academic Search

A series of new chiral ionic liquids have been prepared and characterized starting from a simple, economical, and commercially available monoterpene, citronellal. The aldehyde functionality in citronellal is converted into a Schiff base using an amine, followed by reduction with Raney nickel to give the desired quaternary amine. Most of the ionic liquids generated using this procedure are found to

D. Nageshwar; D. Muralimohan Rao; Palle V. R. Acharyulu

2009-01-01

82

Ionic liquids behave as dilute electrolyte solutions.  

PubMed

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

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

2013-06-11

83

ELECTROCHEMICAL STUDIES OF HEMIN IN IONIC LIQUIDS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Ionic liquids (ILs), room temperature liquid organic salts, have gained prominence as alternative media for volatile organic solvents. Recent studies have shown that some enzymes tolerate ILs and have catalytic activities comparable to those obtained in molecular organic solvents. We have investig...

84

Electrically Switchable Capillarity of Ionic Liquids  

Microsoft Academic Search

Electrocapillarity is the basis of modern electrowetting. And room temperature ionic liquids, an increasingly important set of electrolytes and organic salts that are liquid at room temperature, are considered a novel class of electrowetting agents, because of non-significant vapor pressure, nonflammability, good thermal stability, and a wide useable temperature range. In this paper, a simple device has been fabricated to

Xiaodong Hu; Shiguo Zhang; Chao Qu; Qinghua Zhang; Liujin Lu; Xiangyuan Ma; Xiaoping Zhang; Youquan Deng

2012-01-01

85

Ionic liquid droplet as e-microreactor.  

PubMed

A powerful approach combining a droplet-based, open digital microfluidic lab-on-a-chip using task-specific ionic liquids as soluble supports to perform solution-phase synthesis is reported as a new tool for chemical applications. The negligible volatility of ionic liquids enables their use as stable droplet reactors on a chip surface under air. The concept was validated with different ionic liquids and with a multicomponent reaction. Indeed, we showed that different ionic liquids can be moved by electrowetting on dielectric (EWOD), and their displacement was compared with aqueous solutions. Furthermore, we showed that mixing ionic liquids droplets, each containing a different reagent, in "open" systems is an efficient way of carrying supported organic synthesis. This was applied to Grieco's tetrahydroquinolines synthesis with different reagents. Analysis of the final product was performed off-line and on-line, and the results were compared with those obtained in a conventional reaction flask. This technology opens the way to easy synthesis of minute amounts of compounds ad libitum without the use of complex, expensive, and bulky robots and allows complete automation of the process for embedded chemistry in a portable device. It offers several advantages, including simplicity of use, flexibility, and scalability, and appears to be complementary to conventional microfluidic lab-on-a-chip devices usually based on continuous-flow in microchannels. PMID:16841910

Dubois, Philippe; Marchand, Gilles; Fouillet, Yves; Berthier, Jean; Douki, Thierry; Hassine, Fatima; Gmouh, Said; Vaultier, Michel

2006-07-15

86

Electrochemical transistors with ionic liquids for enzymatic sensing  

E-print Network

Electrochemical transistors with ionic liquids for enzymatic sensing Kevin J. Frasera , Sang Yoon and lactate. Room temperature ionic liquids (RTILs) are organic salts, which are liquid at ambient temperature to ionic liquids (ILs), IL ­ enzyme mixtures and a combination of these novel materials being used on OECTs

Lee, Hyowon

87

TETRAALKYLPHOSPHONIUM POLYOXOMETALATES AS NOVEL IONIC LIQUIDS.  

SciTech Connect

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.

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

2007-11-30

88

Enzyme activity in dialkyl phosphate ionic liquids.  

PubMed

The activity of four metagenomic enzymes and an enzyme cloned from the straw mushroom, Volvariella volvacea were studied in the following ionic liquids, 1,3-dimethylimidazolium dimethyl phosphate, [mmim][dmp], 1-ethyl-3-methylimidazolium dimethyl phosphate, [emim][dmp], 1-ethyl-3-methylimidazolium diethyl phosphate, [emim][dep] and 1-ethyl-3-methylimidazolium acetate, [emim][OAc]. Activity was determined by analyzing the hydrolysis of para-nitrobenzene carbohydrate derivatives. In general, the enzymes were most active in the dimethyl phosphate ionic liquids, followed by acetate. Generally speaking, activity decreased sharply for concentrations of [emim][dep] above 10% v/v, while the other ionic liquids showed less impact on activity up to 20% v/v. PMID:22001053

Thomas, Marie F; Li, Luen-Luen; Handley-Pendleton, Jocelyn M; van der Lelie, Daniel; Dunn, John J; Wishart, James F

2011-12-01

89

Desulfurization of oxidized diesel using ionic liquids  

NASA Astrophysics Data System (ADS)

The extraction of oxidized sulfur compounds from diesel were carried out using ten types of ionic liquids consisting of different cation and anion i.e. 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazoium thiocyanate, 1-butyl-3-methylimidazoium dicyanamide, 1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methylimidazoliumhexafluorophosphate, 1-hexyl-3-methylimidazolium trifluoromethanesulfonate, trioctylmethylammonium chloride, 1-propionitrile-3-butylimidazolium thiocyanate, 1-propionitrile-3-butylimidazolium dicyanamide and 1-butyl-6-methylquinolinium dicyanamide. The oxidation of diesel was successfully done using phosphotungstic acid as the catalyst, hydrogen peroxide (H2O2) as the oxidant and trioctylmethylammonium chloride as the phase transfer agent. The oxidation of diesel changes the sulfur compounds into sulfone which increases its polarity and enhances the ionic liquid's extraction performance. Result showed that ionic liquid [C4mquin][N(CN)2] performed the highest sulfur removal (91% at 1:5 diesel:IL ratio) compared to the others.

Wilfred, Cecilia D.; Salleh, M. Zulhaziman M.; Mutalib, M. I. Abdul

2014-10-01

90

Enzyme activity in dialkyl phosphate ionic liquids  

SciTech Connect

The activity of four metagenomic enzymes and an enzyme cloned from the straw mushroom, Volvariellavolvacea were studied in the following ionic liquids, 1,3-dimethylimidazolium dimethyl phosphate, [mmim][dmp], 1-ethyl-3-methylimidazolium dimethyl phosphate, [emim][dmp], 1-ethyl-3-methylimidazolium diethyl phosphate, [emim][dep] and 1-ethyl-3-methylimidazolium acetate, [emim][OAc]. Activity was determined by analyzing the hydrolysis of para-nitrobenzene carbohydrate derivatives. In general, the enzymes were most active in the dimethyl phosphate ionic liquids, followed by acetate. Generally speaking, activity decreased sharply for concentrations of [emim][dep] above 10% v/v, while the other ionic liquids showed less impact on activity up to 20% v/v.

Thomas, M.F.; Dunn, J.; Li, L.-L.; Handley-Pendleton, J. M.; van der lelie, D.; Wishart, J. F.

2011-12-01

91

Ionic liquids as active pharmaceutical ingredients.  

PubMed

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

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

2011-06-01

92

Unravelling Nanoconfined Films of Ionic Liquids  

E-print Network

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 relative to thermal energy, 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.

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

2014-01-01

93

Unravelling Nanoconfined Films of Ionic Liquids  

E-print Network

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 relative to thermal energy, 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.

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

2014-08-01

94

Transparent ionic liquid-phenol resin hybrids with high ionic conductivity  

Microsoft Academic Search

We report transparent ion conductive ionic liquid-phenol resin hybrids prepared by in situ polymerization\\/crosslinking of phenol monomer in ionic liquid. As ionic liquid, we used highly ion conductive ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide ([EMI][TFSA]). Simultaneous polymerization and crosslinking of phenol with paraformaldehyde in [EMI][TFSA] yielded a highly transparent film. From a field emission scanning electron microscope (FE-SEM) image at 5000 magnification,

Tomoki Ogoshi; Takeshi Onodera; Tada-aki Yamagishi; Yoshiaki Nakamoto; Akihito Kagata; Noriyoshi Matsumi; Keigo Aoi

2011-01-01

95

Acetonitrile Drastically Boosts Conductivity of Ionic Liquids  

E-print Network

We apply a new methodology in the force field generation (PCCP 2011, 13, 7910) to study the binary mixtures of five imidazolium-based room-temperature ionic liquids (RTILs) with acetonitrile (ACN). The investigated RTILs are composed of tetrafluoroborate (BF4) anion and dialkylimidazolium cations, where one of the alkyl groups is methyl for all RTILs, and the other group is different for each RTILs, being ethyl (EMIM), butyl (BMIM), hexyl (HMIM), octyl (OMIM), and decyl (DMIM). Specific densities, radial distribution functions, ionic cluster distributions, heats of vaporization, diffusion constants, shear viscosities, ionic conductivities, and their correlations are discussed. Upon addition of ACN, the ionic conductivity of RTILs is found to increase by more than 50 times, that significantly exceeds an impact of most known solvents. Remarkably, the sharpest conductivity growth is found for the long-tailed imidazolium-based cations. This new fact motivates to revisit an application of these binary systems as a...

Chaban, Vitaly V; Kalugin, Oleg N; Prezhdo, Oleg V

2012-01-01

96

EXPEDITIOUS SYNTHESIS OF IONIC LIQUIDS USING ULTRASOUND AND MICROWAVE IRRADIATION  

EPA Science Inventory

Environmentally friendlier preparations of ionic liquids have been developed that proceed expeditiously under the influence of microwave or ultrasound irradiation conditions using neat reactants, alkylimidazoles and alkyl halides. A number of useful ionic liquids have been prepar...

97

Task-specific microextractions using ionic liquids.  

PubMed

Ionic liquids (ILs) have been the focus of many scientific investigations including the field of analytical microextractions. ILs have many advantages over traditional organic solvents making them excellent candidates as extraction media for a variety of microextraction techniques. Many physical properties of ILs can be varied, and the structural design and make-up can be tuned to impart desired functionality for enhancement of analyte extraction selectivity, efficiency, and sensitivity. This paper provides a brief overview of ionic liquids and highlights trends in three important sample-preparation techniques, namely, single drop microextraction, solid-phase microextraction, and dispersive liquid-liquid microextraction in terms of performing task-specific extractions using these highly versatile solvents. PMID:21400073

Zhao, Qichao; Anderson, Jared L

2011-06-01

98

Application of Task-specific Ionic Liquids for Intensified Separations  

Microsoft Academic Search

Summary.  Ionic liquids offer tremendous opportunities to intensify reactions and separations in process technologies by tuning their\\u000a physical and chemical properties. Several ionic liquids are suitable for the separation of aromatic and aliphatic hydrocarbons.\\u000a CO2 absorption behavior was influenced by the functionalized chains appended to the room temperature ionic liquid (RTIL) cation.\\u000a Ionic liquids seem able to combine the chemical features

G. Wytze Meindersma; Lara M. Galán Sánchez; Antje R. Hansmeier; André B. de Haan

2007-01-01

99

VOC and HAP recovery using ionic liquids  

SciTech Connect

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.

Michael R. Milota : Kaichang Li

2007-05-29

100

Thermal properties of imidazolium ionic liquids  

Microsoft Academic Search

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

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

2000-01-01

101

1,2,3-triazolium ionic liquids  

DOEpatents

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.

Luebke, David; Nulwala, Hunaid; Tang, Chau

2014-12-09

102

Room-temperature ionic liquid battery electrolytes  

Microsoft Academic Search

Room-temperature molten salts possess a number of unique properties that make them ideal battery electrolytes. In particular, they are nonflammable, nonvolatile and chemically inert, and they display wide electrochemical windows, high inherent conductivities and wide thermal operating ranges. Although these ionic liquids have excellent characteristics, the chemical and electrochemical properties of desirable battery electrode materials are not well understood in

R. T. Carlin; J. Fuller

1997-01-01

103

New developments in catalysis using ionic liquids  

Microsoft Academic Search

Ionic liquids are low melting point salts that represent an exciting new class of reaction solvents for catalysis. Being composed entirely of ions, they possess negligible vapour pressures, and the wide range of possible cations and anions means that other solvent properties may be easily controlled. There is currently great interest in the use of these materials as solvents for

Charles M. Gordon

2001-01-01

104

Reactions of Starch in Ionic Liquids  

Technology Transfer Automated Retrieval System (TEKTRAN)

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

105

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...

106

Functionalized imidazolium ionic liquids as electrolyte components of lithium batteries  

Microsoft Academic Search

Some basic properties and compatibility toward lithium electrode for electrolytes based on substituted imidazolium ionic liquid have been investigated. The ionic liquids having imidazolium cation substituted by methylcarboxyl or cyano group suffers from low conductivity. However, reversible lithium deposition–dissolution process was observed in electrolytes based on these electrolytes. In particular, lithium salt solution in cyanomethyl-substituted imidazolium ionic liquid provided similar

Minato Egashira; Hirotaka Todo; Nobuko Yoshimoto; Masayuki Morita; Jun-Ichi Yamaki

2007-01-01

107

Purification of imidazolium ionic liquids for spectroscopic applications  

Microsoft Academic Search

Ionic liquids are often contaminated by colored impurities. These impurities can be problematic for spectroscopic studies or for monitoring organic reactions by UV\\/Vis spectroscopy. The effect of different purification methods on the optical quality of colored ionic liquids was studied and compared. Yellowish ionic liquids can partially be decolorized by treatment with active charcoal or by recrystallization. Our experiments show

Peter Nockemann; Koen Binnemans; Kris Driesen

2005-01-01

108

Hypergolic Ionic Liquids DOI: 10.1002/anie.201101247  

E-print Network

Hypergolic Ionic Liquids DOI: 10.1002/anie.201101247 Generation of Melamine Polymer Condensates upon Hypergolic Ignition of Dicyanamide Ionic Liquids** Konstantin Chingin, Richard H. Perry, Steven D costs and safety require- ments associated with handling hydrazine.[2] Ionic liquids (ILs)[3] have

Zare, Richard N.

109

Biocatalysis in ionic liquids – advantages beyond green technology  

Microsoft Academic Search

In recent years researchers have started to explore a particular class of organic solvents called room temperature ionic liquids — or simply ionic liquids – to identify their unique advantages for biocatalysis. Because they lack vapour pressure, ionic liquids hold potential as green solvents. Furthermore, unlike organic solvents of comparable polarity, they often do not inactivate enzymes, which simplifies reactions

Romas J Kazlauskas

2003-01-01

110

Superbase-derived protic ionic liquids with chelating fluorinated anions  

SciTech Connect

Eighteen new protic ionic liquids were synthesized in one step from five organic superbases and five commercially available fluorinated -diketones. Physical properties of the ionic liquids, including thermal decomposition temperature were determined. Nine of the ionic liquids were examined as extraction media for La3+, with some very large distribution coefficients obtained.

Bell, Jason R [ORNL; Luo, Huimin [ORNL; Dai, Sheng [ORNL

2011-01-01

111

Chiral Ionic Liquids: Synthesis, Properties, and Enantiomeric Recognition  

E-print Network

Chiral Ionic Liquids: Synthesis, Properties, and Enantiomeric Recognition Shaofang Yu, Sergey of structurally novel chiral ionic liquids which have a either chiral cation, chiral anion, or both. Cations and achiral cation toward another chiral molecule such as a quinine derivative. Introduction Ionic liquids

Reid, Scott A.

112

Electrospray from an Ionic Liquid Ferrofluid utilizing the Rosensweig Instability  

E-print Network

Electrospray from an Ionic Liquid Ferrofluid utilizing the Rosensweig Instability Edmond J. Meyer Technological University. This thruster utilized an ionic liquid ferrofluid that was synthesized by suspending magnetic nanoparticles in an ionic liquid carrier solution so that the resulting fluid is superparamagnetic

King, Lyon B.

113

Ionic Liquid Catalyzed the Internal Redox Esterification Reaction  

Microsoft Academic Search

The internal redox esterification of ?, ?-unsaturated aldehydes and alcohols was carried out using different ionic liquids (ILs) as catalysts and reaction solvent. The basic ionic liquid, 1-butyl-3-methylimidazolium acetate ([bmim]OAc) exhibited highest activity for this reaction among them. The influences of the amount of ionic liquid catalyst, and reaction time on yield of saturated ester have been investigated subsequently. The

Yinyin Yu; Li Hua; Wenwen Zhu; Yu Shi; Ting Cao; Yunxiang Qiao; Zhenshan Hou

2012-01-01

114

Ionic liquids in refinery desulfurization: comparison between biphasic and supported ionic liquid phase suspension processes.  

PubMed

The desulfurization of fuel compounds in the presence of ionic liquids is reported. For this purpose, the desulfurization efficiency of a variety of imidazolium phosphate ionic liquids has been tested. Dibenzothiophene/dodecane and butylmercaptan/decane mixtures were used as model systems. Single-stage extractions reduced the sulfur content from 500 ppm to 200 ppm. In multistage extractions the sulfur content could be lowered to less than 10 ppm within seven stages. Regeneration of the ionic liquid was achieved by distillation or re-extraction procedures. Supported ionic liquid phase (SILP) materials, obtained by dispersing the ionic liquid as a thin film on highly porous silica, exhibited a significantly higher extraction performance owing to their larger surface areas, reducing the sulfur content to less than 100 ppm in one stage. Multistage extraction with these SILP materials reduced the sulfur level to 50 ppm in the second stage. The SILP technology offers very efficient utilization of ionic liquids and circumvents mass transport limitations because of the small film thickness and large surface area, and allows application of the simple packed-bed column extraction technique. PMID:19798713

Kuhlmann, Esther; Haumann, Marco; Jess, Andreas; Seeberger, Andreas; Wasserscheid, Peter

2009-01-01

115

Phase behavior of ionic liquid crystals  

E-print Network

Bulk properties of ionic liquid crystals are investigated using density functional theory. The liquid crystal molecules are represented by ellipsoidal particles with charges located in their center or at their tails. Attractive interactions are taken into account in terms of the Gay-Berne pair potential. Rich phase diagrams involving vapor, isotropic and nematic liquid, as well as smectic phases are found. The dependence of the phase behavior on various parameters such as the length of the particles and the location of charges on the particles is studied.

S. Kondrat; M. Bier; L. Harnau

2010-04-15

116

Phase behavior of ionic liquid crystals  

NASA Astrophysics Data System (ADS)

Bulk properties of ionic liquid crystals are investigated using density functional theory. The liquid crystal molecules are represented by ellipsoidal particles with charges located in their center or at their tails. Attractive interactions are taken into account in terms of the Gay-Berne pair potential. Rich phase diagrams involving vapor, isotropic and nematic liquid, as well as smectic phases are found. The dependence of the phase behavior on various parameters such as the length of the particles and the location of charges on the particles is studied.

Kondrat, S.; Bier, M.; Harnau, L.

2010-05-01

117

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

PubMed

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

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

2009-10-01

118

Probing the importance of ionic liquid structure: a general ionic liquid effect on an S(N)Ar process.  

PubMed

The effect of a range of ionic liquids, with systematic variations in the cation and anion, on the rate constant of an aromatic substitution process was investigated. Temperature-dependent kinetic data allowed calculation of activation parameters for the process in each solvent. These data demonstrate a generalised ionic liquid effect, with an increase in rate constant observed in each ionic solvent, though the microscopic origins of the rate constant enhancement differ with the nature of the ionic liquid. PMID:24088815

Tanner, Eden E L; Hawker, Rebecca R; Yau, Hon Man; Croft, Anna K; Harper, Jason B

2013-11-21

119

Dissolution enthalpies of cellulose in ionic liquids.  

PubMed

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

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

2014-11-26

120

Ionic Liquid Membranes for Carbon Dioxide Separation  

SciTech Connect

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.

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

2008-07-12

121

Room temperature ionic liquids and their mixtures—a review  

Microsoft Academic Search

Room temperature ionic liquids are salts that are liquid at room temperature and their use as catalysts and catalytic support has been studied extensively. They are also being considered as “green solvents” for various separation processes. Recent measurements reported on the properties of pure ionic liquids and their mixtures, including gas and liquid solubility in common organic solvents will be

K. N Marsh; J. A Boxall; R Lichtenthaler

2004-01-01

122

Research on the Synthesis of Aromatic Hydrazone in Ionic Liquids  

Microsoft Academic Search

Aromatic hydrazones are important intermediates for pesticides cibenzoline and cefxime. The methodology of synthesis of aromatic hydrazone from aromatic ketone and hydrazine hydrate in ionic liquid, was described and various aromatic hydrazones were prepared by the reaction of aromatic ketone with hydrazine hydrate in ionic 1iquid at 100 °C with good yields. The ionic liquids could be recycled and reused after

Haibin Wang; Li Sun; Xiaonian Li; Jiangli Duan; Wen Pei

2011-01-01

123

Structural modifications of nucleosides in ionic liquids  

PubMed Central

Nucleoside chemistry represents an important research area for drug discovery, as many nucleoside analogs are prominent drugs and have been widely applied for cancer and viral chemotherapy. However, the synthesis of modified nucleosides presents a major challenge, which is further aggravated by poor solubility of these compounds in common organic solvents. Most of the currently available methods for nucleoside modification employ toxic high boiling solvents; require long reaction time and tedious workup methods. As such, there is constant effort to develop process chemistry in alternative medium to limit the use of organic solvents that are hazardous to the environment and can be deleterious to human health. One such approach is to use ionic liquids, which are ‘designer materials’ with unique and tunable physico-chemical properties. Studies have shown that methodologies using ionic liquids are highly efficient and convenient for the synthesis of nucleoside analogs, as demonstrated by the preparation of pharmaceutically important anti-viral drugs. This article summarizes recent efforts on nucleoside modification using ionic liquids. PMID:20178825

Kumar, Vineet; Parmar, Virinder S.; Malhotra, Sanjay V.

2011-01-01

124

Wetting and tribological properties of ionic liquids.  

PubMed

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

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

2014-04-01

125

Anharmonicity and Fragility of Protic Ionic Liquids  

NASA Astrophysics Data System (ADS)

Supercooled liquids are often characterized by their fragility which is associated with physicochemical properties. However, the origin of fragility is still controversial. Superfragile liquid, decahydroisoquinoline (DHiQ) is chosen as a parent molecule to systematically investigate the relationship between anharmonicity and fragility of supercooled liquids. Earlier study by Ueno et al. (J. Phys. Chem. B 2012, 116) demonstrated that the protonation of DHiQ by different Bronsted acids results in the loss of superfragility. To understand the nature of fragile liquids, we conducted inelastic/quasielastic (IE/QE) neutron scattering measurements to examine low frequency vibrational dynamics (boson peak) and the relaxation behavior of DHiQ (high fragility) and DHiQ-based ionic liquids with intermediate (formate, Fm) and low (trifluoromethansulfonimide, TFSI) fragilities. With the protonation, molecular acids will be hydrogen-deficient and the scattering will be dominated by cation, [DHiQ^+]. This strategy simplifies our interpretation in terms of understanding the fitting result from IENS/QENS spectra. By protonating DHiQ with stronger acids, large shift in low frequency vibrational modes and smaller mean square displacements were examined at temperatures higher than Tg. We illustrate how the degree of protonation and ionicity plays a role in the loss in superfragility of DHiQ.

Kim, Jenny; Angell, Austen; Ueno, Kazuhide; Tyagi, Madhu; Soles, Christopher; Masser, Kevin

2013-03-01

126

Maleimide-modified phosphonium ionic liquids: a template towards (multi)task-specific ionic liquids.  

PubMed

The synthesis and characterization of several compounds representing a new class of multitask-specific phosphonium ionic liquids that contain a maleimide functionality is reported. The maleimide moiety of the ionic liquid (IL) is shown to undergo Michael-type additions with substrates containing either a thiol or amine moiety, thus, serving as a template to introduce wide structural diversity into the IL. Multitask-specific ILs are accessible by reaction of the maleimide with Michael donors that are capable of serving some function. As a model example to illustrate this concept, a redox active ferrocenyl thiol was incorporated and examined by cyclic voltammetry. Because the maleimide moiety is highly reactive to additions, the task-specific ionic liquids (TSILs) are prepared as the furan-protected Diels-Alder maleimide. The maleimide moiety can then be liberated when required by simple heating. PMID:20572165

Tindale, Jocelyn J; Hartlen, Kurtis D; Alizadeh, Abdolhamid; Workentin, Mark S; Ragogna, Paul J

2010-08-01

127

Use of ionic liquids as coordination ligands for organometallic catalysts  

DOEpatents

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.

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

2009-11-10

128

SUPPLEMENTARY INFORMATION Double layer in ionic liquids: Overscreening vs. crowding  

E-print Network

SUPPLEMENTARY INFORMATION Double layer in ionic liquids: Overscreening vs. crowding Martin Z the relationship between D and E = -. To model the field energy in an ionic liquid, we assume linear dielectric energy cost for adding a charge in the bulk liquid volume V or qs on the metal surface S is, Gel = V dr

Bazant, Martin Z.

129

Application of ionic liquids as solvents for polymerization processes  

Microsoft Academic Search

Ionic liquids are organic salts that are liquid at ambient temperatures. They are non-volatile, highly polar solvents that dissolve several organic, inorganic and metaloorganic compounds. Although there is an increasing number of reports dealing with the application of ionic liquids as solvents for organic synthesis, their use in polymer synthesis is still limited. In the last few years, however, it

Przemyslaw Kubisa

2004-01-01

130

Oxidative enzymes possess catalytic activity in systems with ionic liquids  

Microsoft Academic Search

Oxidative enzymes, laccase C from Trametes sp. and horseradish and soybean peroxidases, catalyzed oxidation reactions in systems with ionic liquids whose content varied from several volume percent to almost total non-aqueous ionic liquids. Similar to the effects produced by standard organic solvents used in non-aqueous enzymology, catalytic activity of the enzymes was decreased by adding a water-miscible ionic liquid, 4-methyl-N-butylpyridinium

Glen Hinckley; Vadim V. Mozhaev; Cheryl Budde; Yuri L. Khmelnitsky

2002-01-01

131

Electrotunable Lubricity with Ionic Liquid Nanoscale Films  

NASA Astrophysics Data System (ADS)

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.

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

2015-01-01

132

Electrotunable Lubricity with Ionic Liquid Nanoscale Films  

PubMed Central

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

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

2015-01-01

133

Electrotunable lubricity with ionic liquid nanoscale films.  

PubMed

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

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

2015-01-01

134

Lipid extraction from microalgae using a single ionic liquid  

DOEpatents

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

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

2013-05-28

135

Ionic Liquids and Ionizing Radiation: Reactivity of Highly Energetic Species  

SciTech Connect

Due to their unique properties, ionic liquids present many opportunities for basic research on the interactions of radiation with materials under conditions not previously available. At the same time, there are practical applied reasons for characterizing, understanding, and being able to predict how ionic-liquid-based devices and industrial-scale systems will perform under conditions of extreme reactivity, including radiation. This perspective discusses current issues in ionic liquid physical chemistry, provides a brief introduction to radiation chemistry, draws attention to some key findings in ionic liquid radiation chemistry, and identifies some current hot topics and new opportunities.

Wishart, J.F.

2010-11-04

136

Durable electrooptic devices comprising ionic liquids  

DOEpatents

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.

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

137

Ionic liquid assisted electrospinning of quantum dots/elastomer composite Jiahua Zhu a  

E-print Network

Ionic liquid assisted electrospinning of quantum dots/elastomer composite nanofibers Jiahua Zhu wt%) of ionic liquid. Without ionic liquid, polymer solution underwent an electrospraying process between ionic liquid and the polymer chains, which well explains the function of the ionic liquid

Guo, John Zhanhu

138

Nonlinear capacitance and electrochemical behavior of ionic liquid-ionic polymer transducers  

NASA Astrophysics Data System (ADS)

Ionic polymer transducers (IPTs) are soft sensors and actuators which operate through a coupling of micro-scale chemical, electrical, and mechanical interactions. The use of an ionic liquid as solvent for an IPT has been shown to dramatically increase transducer lifetime in free-air use, while also allowing for higher applied voltages without electrolysis. In this work we model charge transport in an ionic liquid IPT by considering both the cation and anion of the ionic liquid as mobile charge carriers, a phenomenon which is unique to ionic liquid IPTs compared to their water-based counterparts. The electrochemical behavior of the large ionic liquid ions is described through a modification of the Nernst-Planck equation given by Kornyshev which accounts for steric effects in double layer packing. The method of matched asymptotic expansions is applied to solve the resulting system of equations, and analytical expressions are derived for the nonlinear charge transferred and capacitance of the IPT as a function of the applied voltage. The influence of the fraction of mobile ionic liquid ions and steric effects on the capacitance of an ionic liquid IPT is shown and compared to water-based IPTs. These results show the fundamental charge transport differences between water-based and ionic liquid IPTs and give considerations for future transducer development.

Davidson, Jacob D.; Goulbourne, N. C.

2010-04-01

139

Toxicity of ionic liquids prepared from biomaterials.  

PubMed

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

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

2014-06-01

140

Oxygen Extraction from Regolith Using Ionic Liquids  

NASA Technical Reports Server (NTRS)

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.

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

2011-01-01

141

Tetraalkylphosphonium polyoxometalates : Electroactive, 'task-specific' ionic liquids.  

SciTech Connect

The pairing of selected polyoxometalate (POM) anions with appropriate tetraalkylphosphonium cations is shown to yield an original family of ionic liquids, among them an ambient-temperature 'liquid POM.'

Rickert, P. G.; Antonio, M. R.; Firestone, M. A.; Kubatko, K-A.; Szreder, T.; Wishart, J. F.; Dietz, M. L.; BNL; Univ. of Miami

2007-01-01

142

Tetraalkylphosphonium polyoxometalates: electroactive, "task-specific" ionic liquids.  

PubMed

The pairing of selected polyoxometalate (POM) anions with appropriate tetraalkylphosphonium cations is shown to yield an original family of ionic liquids, among them an ambient-temperature "liquid POM". PMID:17225903

Rickert, Paul G; Antonio, Mark R; Firestone, Millicent A; Kubatko, Karrie-Ann; Szreder, Tomasz; Wishart, James F; Dietz, Mark L

2007-02-01

143

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

PubMed

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

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

2014-09-01

144

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

E-print Network

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, ...

Courtney, Daniel George

2011-01-01

145

Graphene as ion sensitive film for ionic liquids  

Microsoft Academic Search

Graphene is a two dimensional material with extremely favorable sensing properties. In the present work we proposed the use of graphene films for the conductivity measurements of ionic liquids. Recently ionic liquids have attracted enormous attention for green synthesis and their applications in fuel cells, solar cells and batteries. Here we show the feasibility to use graphene films for measurement

Atul Kulkarni; Hyeongkeun Kim; Hang Zang; Jae-Boong Choi; Byung Hee Hong; Tae Sung Kim

2010-01-01

146

Investigation of ionic liquids as electrolytes for carbon nanotube electrodes  

Microsoft Academic Search

The use of ionic liquids (IL) as electrolytes for electrochemical applications involving carbon nanotube (CNT) electrodes has been investigated in a brief initial study. The use of IL electrolytes in conjunction with CNT electrodes has proved possible and advantageous. Ionic liquids provide relatively high conductivity, wide potential window (up to 5.5 V) along with chemical stability and nonvolatile nature. While

J. N Barisci; G. G Wallace; D. R MacFarlane; R. H Baughman

2004-01-01

147

Molecular Dynamics Modeling of Ionic Liquids in Electrospray Propulsion  

E-print Network

of Technology. 1 #12;2 #12;Molecular Dynamics Modeling of Ionic Liquids in Electrospray Propulsion by NanakoMolecular Dynamics Modeling of Ionic Liquids in Electrospray Propulsion Nanako Takahashi, Paulo C Propulsion Nanako Takahashi, Paulo C. Lozano June 2010 SSL # 6-10 This work is based on the unaltered text

148

Ionic Liquids and Green Chemistry: A Lab Experiment  

ERIC Educational Resources Information Center

Although ionic liquids have been investigated as solvents for many applications and are starting to be used in industrial processes, only a few lab experiments are available to introduce students to these materials. Ionic liquids have been discussed in the context of green chemistry, but few investigations have actually assessed the degree of…

Stark, Annegret; Ott, Denise; Kralisch, Dana; Kreisel, Guenter; Ondruschka, Bernd

2010-01-01

149

Brownian dynamics determine universality of charge transport in ionic liquids  

SciTech Connect

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.

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

150

Ionic liquids: perspectives for organic and catalytic reactions  

Microsoft Academic Search

Ionic liquids are attracting a great deal of attention as possible replacement for conventional molecular solvents for catalytic and organic reactions. They complete the use of environmentally friendly water, supercritical fluids or perfluorinated solvents. Features that make ionic liquids attractive include their lack of vapor pressure and the great versatility of their chemical and physical properties. By a judicious combination

Hélène Olivier-Bourbigou; Lionel Magna

2002-01-01

151

Structure and magnetic behavior of transition metal based ionic liquids  

SciTech Connect

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.

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

152

Magnetic nanoparticles supported ionic liquids improve firefly luciferase properties.  

PubMed

Ionic liquids as neoteric solvents, microwave irradiation, and alternative energy source are becoming as a solvent for many enzymatic reactions. We recently showed that the incubation of firefly luciferase from Photinus pyralis with various ionic liquids increased the activity and stability of luciferase. Magnetic nanoparticles supported ionic liquids have been obtained by covalent bonding of ionic liquids-silane on magnetic silica nanoparticles. In the present study, the effects of [?-Fe2O3@SiO2][BMImCl] and [?-Fe2O3@SiO2][BMImI] were investigated on the structural properties and function of luciferase using circular dichroism, fluorescence spectroscopy, and bioluminescence assay. Enzyme activity and structural stability increased in the presence of magnetic nanoparticles supported ionic liquids. Furthermore, the effect of ingredients which were used was not considerable on K(m) value of luciferase for adenosine-5'-triphosphate and also K(m) value for luciferin. PMID:24492953

Noori, Ali Reza; Hosseinkhani, Saman; Ghiasi, Parisa; Akbari, Jafar; Heydari, Akbar

2014-03-01

153

Solid-ionic liquid interfaces: pore filling revisited.  

PubMed

The properties of ionic liquids on ordered and non-ordered mesoporous silicas (silica gel, MCM-41, SBA-15) were studied by nitrogen sorption, mercury intrusion and thermogravimetric analyses, as well as (129)Xe-NMR spectroscopy. The ionic liquids investigated are based on the 1-hexyl-3-methylimidazolium cation, which was combined with anions of low (bis(trifluoromethanesulfonyl)imide; [NTf2](-)), medium (trifluoromethylsulfonate; [CF3SO3](-)) to high (acetate; [OAc](-)) basicity. The surface coverage depends on both the type of ionic liquid and support used. This results not only in layer or droplet formation, but also in different physico-chemical properties of the ionic liquid when compared to the bulk, depending mainly on the strength of interaction at the interface. Furthermore, the mercury intrusion analysis of mesopores is shown not to be suitable for supported ionic liquids. PMID:25300707

Heinze, M T; Zill, J C; Matysik, J; Einicke, W D; Gläser, R; Stark, A

2014-11-28

154

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

PubMed

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

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

2015-05-01

155

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

PubMed

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

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

156

Carbon Dioxide and Ionic Liquid Refrigerants: Compact, Efficient Air Conditioning with Ionic Liquid-Based Refrigerants  

SciTech Connect

BEETIT Project: Notre Dame is developing an air-conditioning system with a new ionic liquid and CO2 as the working fluid. Synthetic refrigerants used in air conditioning and refrigeration systems are potent GHGs and can trap 1,000 times more heat in the atmosphere than CO2 alone—making CO2 an attractive alternative for synthetic refrigerants in cooling systems. However, operating cooling systems with pure CO2 requires prohibitively high pressures and expensive hardware. Notre Dame is creating a new fluid made of CO2 and ionic liquid that enables the use of CO2 at low pressures and requires minimal changes to existing hardware and production lines. This new fluid also produces no harmful emissions and can improve the efficiency of air conditioning systems— enabling new use of CO2 as a refrigerant in cooling systems.

None

2010-10-01

157

Ionic liquids as advanced lubricant fluids.  

PubMed

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

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

2009-01-01

158

Metsulfuron-methyl-based herbicidal ionic liquids.  

PubMed

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

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

2015-04-01

159

Durable Electrooptic Devices Comprising Ionic Liquids  

DOEpatents

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. Some of the electrolyte solutions color to red when devices employing the solutions are powered, leading to red or neutral electrooptic devices.

Burrell, Anthony K. (Los Alamos, NM); 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)

2008-11-11

160

Durable electrooptic devices comprising ionic liquids  

DOEpatents

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. Some of the electrolyte solutions color to red when devices employing the solutions are powered, leading to red or neutral electrooptic devices.

Burrell, Anthony K. (Los Alamos, NM); 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)

2009-12-15

161

Durable electrooptic devices comprising ionic liquids  

DOEpatents

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.

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

2006-10-10

162

Room-temperature ionic liquid battery electrolytes  

SciTech Connect

The room-temperature molten salts possess a number of unique properties that make them ideal battery electrolytes. In particular, they are nonflammable, nonvolatile, and chemically inert, and they display wide electrochemical windows, high inherent conductivities, and wide thermal operating ranges. Although the ionic liquids have excellent characteristics, the chemical and electrochemical properties of desirable battery electrode materials are not well understood in these electrolytes. The research has focused on rechargeable electrodes and has included work on metallic lithium and sodium anodes in buffered neutral chloroaluminate melts, graphite-intercalation electrodes in neutral chloroaluminate and non-chloroaluminate melts, and silane-imidazole polymeric cathodes in acidic chloroaluminate melts. This paper will provide an overview of the research in these areas.

Carlin, R.T.; Fuller, J. [Covalent Associates, Inc., Woburn, MA (United States)

1997-12-01

163

Morita-Baylis-Hillman reaction: ESI-MS(/MS) investigation with charge tags and ionic liquid effect origin revealed by DFT calculations.  

PubMed

The use of a charge-tagged acrylate derivative bearing an imidazolium tag to study the Morita-Baylis-Hillman reaction via ESI-MS(/MS) monitoring and the effect of such tag (imidazolium cations and ion pairs) over TSs is described. The ionic nature of the substrate was meant to facilitate ESI transfer to the gas phase for direct mass spectrometric analysis. The detection and characterization of charged intermediates has suggested major reaction pathways. DFT calculations considering the effect of a polar and protic solvent (methanol), of a polar and aprotic solvent (acetonitrile), and of no solvent (gas phase) were used to predict possible TSs through a common accepted intermediate. The controversial proton transfer step, which may proceed via Aggarwal's or McQuade's proposals, was evaluated. Calculations predicted the formation of electrostatic intermediate complexes with both the cation and anion when charge-tagged reagents are used. These complexes contribute to the positive ionic liquid effect, and based on the formation of these unique complexes, a rationale for the ionic liquid effect is proposed. These complexes also pointed to a plausible explanation for the positive ionic liquid effect observed in several reactions that are difficult to be carried out in organic solvents but have shown a beneficial effect when performed in ionic liquids. PMID:24815995

Rodrigues, Thyago S; Silva, Valter H C; Lalli, Priscila M; de Oliveira, Heibbe C B; da Silva, Wender A; Coelho, Fernando; Eberlin, Marcos N; Neto, Brenno A D

2014-06-01

164

Novel bipyridinium ionic liquids as liquid electrochromic devices.  

PubMed

Novel mono and dialkylbipyridinium (viologens) cations combined with iodide, bromide, or bis(trifluoromethanesulfonyl)imide [NTf2] as anions were developed. Selective alkylation synthetic methodologies were optimized in order to obtain the desired salts in moderate to high yields and higher purities. All prepared mono- and dialkylbipyridinium salts were completely characterized by (1)H, (13)C, and (19)F?NMR spectroscopy, Fourier-transform IR spectroscopy, and elemental analysis (in the case of NTf2 salts). Melting points, glass transition temperatures by differential scanning calorimetry (DSC) studies, and decomposition temperatures were also checked for different prepared organic salts. Viscosities at specific temperatures and activation energies were determined by rheological studies (including viscosity dependence with temperature in heating and cooling processes). Electrochemical studies based on cyclic voltammetry (CV), differential pulsed voltammetry (DPV), and square-wave voltammetry (SWV) were performed in order to determine the redox potential as well as evaluate reversibility behavior of the novel bipyridinium salts. As proof of concept, we developed a reversible liquid electrochromic device in the form of a U-tube system, the most promising dialkylbipyridinium-NTf2 ionic liquid being used as the electrochromic material and the room-temperature ionic liquid (RTIL), 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)-imide [EMIM][NTf2], as a stable and efficient electrolyte. PMID:24577754

Jordão, Noémi; Cabrita, Luis; Pina, Fernando; Branco, Luís C

2014-04-01

165

Task-specific ionic liquids for efficient ammonia absorption  

Microsoft Academic Search

A computational-experimental study was carried out to select ionic liquids with optimized properties for absorption of ammonia (NH3). Firstly, a quantum-chemical COSMO-RS analysis was performed to analyze the solute–solvent intermolecular interactions determining the gas–liquid equilibrium data. Subsequently, a rational COSMO-RS screening of Henry’s law coefficient of NH3 over 272 ionic liquids was done to select potential high-capacity ammonia solvents. Finally,

Jose Palomar; Maria Gonzalez-Miquel; Jorge Bedia; Francisco Rodriguez; Juan J. Rodriguez

2011-01-01

166

Soft ionization of thermally evaporated hypergolic ionic liquid aerosols  

SciTech Connect

Isolated ion pairs of a conventional ionic liquid, 1-Ethyl-3-Methyl-Imidazolium Bis(trifluoromethylsulfonyl)imide ([Emim+][Tf2N?]), and a reactive hypergolic ionic liquid, 1-Butyl-3-Methyl-Imidazolium Dicyanamide ([Bmim+][Dca?]), are generated by vaporizing ionic liquid submicron aerosol particles for the first time; the vaporized species are investigated by dissociative ionization with tunable vacuum ultraviolet (VUV) light, exhibiting clear intact cations, Emim+ and Bmim+, presumably originating from intact ion pairs. Mass spectra of ion pair vapor from an effusive source of the hypergolic ionic liquid show substantial reactive decomposition due to the internal energy of the molecules emanating from the source. Photoionization efficiency curves in the near threshold ionization region of isolated ion pairs of [Emim+][Tf2N?]ionic liquid vapor are compared for an aerosol source and an effusive source, revealing changes in the appearance energy due to the amount of internal energy in the ion pairs. The aerosol source has a shift to higher threshold energy (~;;0.3 eV), attributed to reduced internal energy of the isolated ion pairs. The method of ionic liquid submicron aerosol particle vaporization, for reactive ionic liquids such as hypergolic species, is a convenient, thermally ?cooler? source of isolated intact ion pairs in the gas phase compared to effusive sources.

University of California; ERC, Incorporated, Edwards Air Force Base; Air Force Research Laboratory, Edwards Air Force Base; National Synchrotron Radiation Research Center (NSRRC); Institute of Chemistry, Hebrew University; Koh, Christine J.; Liu, Chen-Lin; Harmon, Christopher W.; Strasser, Daniel; Golan, Amir; Kostko, Oleg; Chambreau, Steven D.; Vaghjiani, Ghanshyam L.; Leone, Stephen R.

2011-07-19

167

Soft ionization of thermally evaporated hypergolic ionic liquid aerosols  

SciTech Connect

Isolated ion pairs of a conventional ionic liquid, 1-Ethyl-3-Methyl-Imidazolium Bis(trifluoromethylsulfonyl)imide ([Emim+][Tf2N?]), and a reactive hypergolic ionic liquid, 1- Butyl-3-Methyl-Imidazolium Dicyanamide ([Bmim+][Dca?]), are generated by vaporizing ionic liquid submicron aerosol particles for the first time; the vaporized species are investigated by dissociative ionization with tunable vacuum ultraviolet (VUV) light, exhibiting clear intact cations, Emim+ and Bmim+, presumably originating from intact ion pairs. Mass spectra of ion pair vapor from an effusive source of the hypergolic ionic liquid show substantial reactive decomposition due to the internal energy of the molecules emanating from the source. Photoionization efficiency curves in the near threshold ionization region of isolated ion pairs of [Emim+][Tf2N?] ionic liquid vapor are compared for an aerosol source and an effusive source, revealing changes in the appearance energy due to the amount of internal energy in the ion pairs. The aerosol source has a shift to higher threshold energy (~;;0.3 eV), attributed to reduced internal energy of the isolated ion pairs. The method of ionic liquid submicron aerosol particle vaporization, for reactive ionic liquids such as hypergolic species, is a convenient, thermally ?cooler? source of isolated intact ion pairs in the gas phase compared to effusive sources.

University of California; ERC, Incorporated, Edwards Air Force Base; Air Force Research Laboratory, Edwards Air Force Base; National Synchrotron Radiation Research Center (NSRRC); Koh, Christine J.; Liu, Chen-Lin; Harmon, Christopher W.; Strasser, Daniel; Golan, Amir; Kostko, Oleg; Chambreau, Steven D.; L.Vaghjiani, Ghanshyam; Leone, Stephen R.

2012-03-16

168

Ionic liquids of cationic sandwich complexes.  

PubMed

Simple cationic sandwich complexes that contained alkyl- or halogen substituents provided ionic liquids (ILs) with the bis(perfluoroalkanesulfonyl)imide anion. Ferrocenium- and cobaltocenium ILs [M(C(5)H(4)R(1))(C(5)H(4)R(2))][Tf(2)N] (M=Fe, Co) and arene-ferrocenium ILs [Fe(C(5)H(4)R(1))(C(6)H(5)R(2))][Tf(2)N] were prepared and their physical properties were investigated. A detailed comparison of their thermal properties revealed the effects of molecular symmetry and substituents on their melting points. Their viscosity increased on increasing the length of the substituent on the cation and the perfluoroalkyl chain length on the anion. Upon cooling, ILs with low viscosities exhibited crystallization, whereas those with higher viscosities tended to exhibit glass transitions. Most of these salts showed phase transitions in the solid state. A magnetic-switching phenomenon was observed for the paramagnetic ferrocenium IL, which was associated with a liquid/solid transformation, based on the magnetic anisotropy of the ferrocenium cation. (57)Fe Mössbauer spectroscopy was applied to [Fe(C(5)H(4)nBu)(2)][Tf(2)N] to investigate the vibrational behavior of the iron atom in the crystal and glassy states of the ferrocenium IL. PMID:22517602

Inagaki, Takashi; Mochida, Tomoyuki; Takahashi, Masashi; Kanadani, Chikahide; Saito, Toshiaki; Kuwahara, Daisuke

2012-05-29

169

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

PubMed

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

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

2013-10-21

170

An imidazolium based ionic liquid electrolyte for lithium batteries  

Microsoft Academic Search

An electrolyte for lithium batteries based on the ionic liquid 3-methy-1-propylimidazolium bis(trifluoromethysulfony)imide (PMIMTFSI) complexed with lithium bis(trifluoromethysulfony)imide (LiTFSI) at a molar ratio of 1:1 has been investigated. The electrolyte shows a high ionic conductivity (?1.2×10?3Scm?1) at room temperature. Over the whole investigated temperature range the ionic conductivity is more than one order of magnitude higher than for an analogue electrolyte

Jae-Kwang Kim; Aleksandar Matic; Jou-Hyeon Ahn; Per Jacobsson

2010-01-01

171

Development of Practical Supported Ionic Liquid Membranes: A Systematic Approach  

SciTech Connect

Supported liquid membranes (SLMs) are a class of materials that allow the researcher to utilize the wealth of knowledge available on liquid properties to optimize membrane performance. These membranes also have the advantage of liquid phase diffusivities, which are higher than those observed in polymers and 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 may possess high CO2 solubility relative to light gases such as H2, are excellent candidates for this type of membrane since they are stable at elevated temperatures and have negligible vapor pressure. A study has been conducted evaluating the use of a variety of ionic liquids 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 membrane performance for the resulting materials. Several steps have been taken in the development of practical supported ionic liquid membranes. Proof-of-concept was established by showing that ionic liquids could be used as the transport media in SLMs. Results showed that ionic liquids are suitable media for gas transport, but the preferred polymeric supports were not stable at temperatures above 135oC. The use of cross-linked nylon66 supports was found to produce membranes mechanically stable at temperatures exceeding 300oC but CO2/H2 selectivity was poor. An ionic liquid whose selectivity does not decrease with increasing temperature was needed, and a functionalized ionic liquid that complexes with CO2 was used. An increase in CO2/H2 selectivity with increasing temperature over the range of 37 to 85oC was observed and the dominance of a facilitated transport mechanism established. The presentation will detail membrane development, the effect of increasing transmembrane pressure, and preliminary results dealing with other gas pairs and contaminants.

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

2007-11-01

172

Phase-Changing Ionic Liquids: CO2 Capture with Ionic Liquids Involving Phase Change  

SciTech Connect

IMPACCT Project: Notre Dame is developing a new CO2 capture process that uses special ionic liquids (ILs) to remove CO2 from the gas exhaust of coal-fired power plants. ILs are salts that are normally liquid at room temperature, but Notre Dame has discovered a new class of ILs that are solid at room temperature and change to liquid when they bind to CO2. Upon heating, the CO2 is released for storage, and the ILs re-solidify and donate some of the heat generated in the process to facilitate further CO2 release. These new ILs can reduce the energy required to capture CO2 from the exhaust stream of a coal-fired power plant when compared to state-ofthe- art technology.

None

2010-07-01

173

Ionogels, ionic liquid based hybrid materials.  

PubMed

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

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

2011-02-01

174

Charge Transport and Glassy Dynamics in Ionic Liquids  

Microsoft Academic Search

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

Kremer; Friedrich

2012-01-01

175

Using Caenorhabditis elegans to probe toxicity of 1-alkyl-3-methylimidazolium chloride based ionic liquids  

E-print Network

13th January 2004 First published as an Advance Article on the web 10th February 2004 Ionic liquids toxicological effects of 1-alkyl-3-methyli- midazolium chloride ionic liquids. Ionic liquids are quickly gaining to the negligible vapor pressures of ionic liquids when compared to traditional volatile organic solvents. To date

Caldwell, Guy

176

CO 2 separation facilitated by task-specific ionic liquids using a supported liquid membrane  

Microsoft Academic Search

We report a supported liquid membrane (SLM) based on a task-specific ionic liquid to achieve the selective and facilitated CO2 transport through the membrane. The prepared SLM facilitated by the amine-terminated ionic liquid showed high selectivity and high stability (more than 260 days) for CO2 separation from the CO2\\/CH4 gas mixture.

Shoji Hanioka; Tatsuo Maruyama; Tomohiro Sotani; Masahiro Teramoto; Hideto Matsuyama; Kazunori Nakashima; Misa Hanaki; Fukiko Kubota; Masahiro Goto

2008-01-01

177

Shear and Extensional Rheology of Cellulose/Ionic Liquid Solutions  

E-print Network

In this study, we characterize the shear and extensional rheology of dilute to semidilute solutions of cellulose in the ionic liquid 1-ethyl-3-methylimidazolium acetate (EMIAc). In steady shear flow, the semidilute solutions ...

Haward, Simon J.

178

Ionic Liquid Co-catalyzed Artificial Photosynthesis of CO  

NASA Astrophysics Data System (ADS)

The conversion of CO2 to chemical feedstocks is of great importance, which yet requires the activation of thermodynamically-stable CO2 by metal catalysts or metalloenzymes. Recently, the development of metal-free organocatalysts for use in CO2 activation under ambient conditions has opened new avenues for carbon fixation chemistry. Here, we report the capture and activation of CO2 by ionic liquids and coupling to photoredox catalysis to synthesize CO. The chemical nature of anions and the organic functional groups on the imidazolium cations of ionic liquids, together with reaction medium have been demonstrated to have remarkable effects on the activation and reduction of CO2. Considering almost unlimited structural variations of ionic liquids by a flexible combination of cations and anions, this photochemical pathway provides unique opportunities for carbon fixation by rationally-designed chemical systems via linking ionic liquid based materials with chromorphoric molecules in tackling the great challenges of artificial photosynthesis.

Lin, Jinliang; Ding, Zhengxin; Hou, Yidong; Wang, Xinchen

2013-01-01

179

Robust and versatile ionic liquid microarrays achieved by microcontact printing  

NASA Astrophysics Data System (ADS)

Lab-on-a-chip and miniaturized systems have gained significant popularity motivated by marked differences in material performance at the micro-to-nano-scale realm. However, to fully exploit micro-to-nano-scale chemistry, solvent volatility and lack of reproducibility need to be overcome. Here, we combine the non-volatile and versatile nature of ionic liquids with microcontact printing in an attempt to establish a facile protocol for high throughput fabrication of open microreactors and microfluidics. The micropatterned ionic liquid droplets have been demonstrated as electrochemical cells and reactors for microfabrication of metals and charge transfer complexes, substrates for immobilization of proteins and as membrane-free high-performance amperometric gas sensor arrays. The results suggest that miniaturized ionic liquid systems can be used to solve the problems of solvent volatility and slow mass transport in viscous ionic liquids in lab-on-a-chip devices, thus providing a versatile platform for a diverse number of applications.

Gunawan, Christian A.; Ge, Mengchen; Zhao, Chuan

2014-04-01

180

Double Layer in Ionic Liquids: Overscreening versus Crowding  

E-print Network

We develop a simple Landau-Ginzburg-type continuum theory of solvent-free ionic liquids and use it to predict the structure of the electrical double layer. The model captures overscreening from short-range correlations, ...

Bazant, Martin Z.

181

The radiation chemistry of ionic liquids: a review  

SciTech Connect

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.

Bruce J. Mincher; James F. Wishart

2014-07-01

182

Room temperature lithium polymer batteries based on ionic liquids  

Microsoft Academic Search

In this manuscript are reported the results of an investigation performed on rechargeable, all-solid-state, solvent-free, Li\\/LiFePO4 polymer batteries incorporating N-butyl-N-methyl-pyrrolidinium bis(trifluoromethanesulfonyl)imide, PYR14TFSI, ionic liquid (IL). The tests show clearly the beneficial effect due to the incorporation of ionic liquids on room temperature battery performance that, conversely, results extremely poor in IL-free lithium polymer batteries. The theoretical capacity is delivered at

G. B. Appetecchi; G. T. Kim; M. Montanino; F. Alessandrini; S. Passerini

2011-01-01

183

Ionic liquid-catalyzed alkylation of isobutane with 2-butene  

Microsoft Academic Search

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, respectively. The emphasis has been to delineate the role of both cations and anions in this reaction. The ionic liquids

Kyesang Yoo; Vasudevan V Namboodiri; Rajender S Varma; Panagiotis G Smirniotis

2004-01-01

184

Membrane contactor assisted extraction/reaction process employing ionic liquids  

DOEpatents

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.

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

2012-02-07

185

Room Temperature Ionic Liquids for Separating Organics from Produced Water  

Microsoft Academic Search

The distribution of polar organic compounds typical of water contaminants (organic acids, alcohols, and aromatic compounds) associated with oil and gas production was measured between water and nine hydrophobic, room?temperature ionic liquids. The ionic liquids used in this study were 1?butyl?3?methylimidazolium bistrifluoromethanesulfonylimide, 1?hexyl?3?methylimidazolium bistrifluoromethanesulfonylimide, 1?octyl?3?methylimidazolium bistrifluoromethanesulfonylimide, 1?butyl?3?methylimidazolium hexafluorophosphate, trihexyltetradecylphosphonium bistrifluoromethanesulfonylimide, 1?butyl?1?methyl?pyrrolidinium bistrifluoromethanesulfonylimide, trihexyltetradecylphosphonium dodecylbenzenesulfonate, tributyltetradecylphosphonium dodecylbenzenesulfonate, and trihexyltetradecylphosphonium methanesulfonate. Sensitivity

J. McFarlane; W. B. Ridenour; H. Luo; R. D. Hunt; D. W. DePaoli; R. X. Ren

2005-01-01

186

Novel imidazolium chiral ionic liquids that contain a urea functionality  

Microsoft Academic Search

Nine chiral room temperature ionic liquids (RTILs), which contain a chiral moiety and a urea functionality bonded to a imidazolium ring, have been designed and synthesized. The synthesis of these ionic liquids is concise and practical due to the commercial availability of the starting materials. These novel RTILs were readily prepared from 1-(3-aminopropyl)imidazole and amino acid ester derived isocyanates. We

Bukuo Ni; Allan D. Headley

2006-01-01

187

Ionic liquid propellants: future fuels for space propulsion.  

PubMed

Use of green propellants is a trend for future space propulsion. Hypergolic ionic liquid propellants, which are environmentally-benign while exhibiting energetic performances comparable to hydrazine, have shown great potential to meet the requirements of developing nontoxic high-performance propellant formulations for space propulsion applications. This Concept article presents a review of recent advances in the field of ionic liquid propellants. PMID:24136866

Zhang, Qinghua; Shreeve, Jean'ne M

2013-11-11

188

Diphosphonium Ionic Liquids as Broad Spectrum Antimicrobial Agents  

PubMed Central

Purpose One of the most disturbing trends in recent years is the growth of resistant strains of bacteria with the simultaneous dearth of new antimicrobial agents. Thus, new antimicrobial agents for use on the ocular surface are needed. Methods We synthesized a variety of ionic liquid compounds, which possess two positively charged phosphonium groups separated by ten methylene units in a “bola” type configuration. We tested these compounds for antimicrobial activity versus a variety of ocular pathogens, as well as their cytoxicity in vitro in a corneal cell line and in vivo in mice. Results The ionic liquid Di-Hex C10 demonstrated broad in vitro antimicrobial activity at the low micromolar concentrations versus Gram-negative and Gram-positive organisms, including methicillin-resistant Staphylococcus aureus strains, as well as ocular fungal pathogens. Treatment with Di-Hex C10 resulted in bacterial killing in as little as 15 minutes in vitro. Di-Hex C10 showed little cytotoxicity at 1 ?M versus a corneal epithelial cell line or at 10 ?M in a mouse corneal wound model. We also show that this bis-phosphonium ionic liquid structure is key, as a comparable mono phosphonium ionic liquid is cytotoxic to both bacteria and corneal epithelial cells. Conclusions Here we report the first use of dicationic bis-phosphonium ionic liquids as antimicrobial agents. Our data suggest that diphosphonium ionic liquids may represent a new class of broad-spectrum antimicrobial agents for use on the ocular surface. PMID:22236790

O’Toole, George A.; Wathier, Michel; Zegans, Michael E.; Shanks, Robert M.Q.; Kowalski, Regis; Grinstaff, Mark W.

2011-01-01

189

Supported and liquid phase task specific ionic liquids for base catalysed Knoevenagel reactions  

Microsoft Academic Search

A series of Hünig's base tethered ammonium ionic liquids have been used to catalyse the Knoevenagel condensation of aldehydes\\/ketones with malononitrile and ethyl cyanoacetate. The reactions were performed under homogeneous and under biphasic, liquid–liquid and liquid–silica supported ionic liquid, conditions with the biphasic systems employing cyclohexene as the second phase. By increasing the distance between the ammonium head group and

C. Paun; J. Barklie; P. Goodrich; H. Q. N. Gunaratne; A. McKeown; V. I. Pârvulescu; C. Hardacre

2007-01-01

190

Carbon Dioxide Separation with Supported Ionic Liquid Membranes  

SciTech Connect

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.

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

2007-04-01

191

Physicochemical properties determined by ?pKa for protic ionic liquids based on an organic super-strong base with various Brønsted acids.  

PubMed

Neutralization of an organic super-strong base, 1,8-diazabicyclo-[5,4,0]-undec-7-ene (DBU), with different Brønsted acids affords a novel series of protic ionic liquids (PILs) with wide variations in the ?pK(a) of the constituent amine and acids. The physicochemical properties of these PILs, such as thermal properties, density, conductivity, viscosity, self-diffusion coefficient, vibrational stretching frequency, and (1)H-chemical shifts of the N-H bond, have been studied in detail. The generated PILs have melting temperatures below 100 °C, and six are liquids at ambient temperatures. Thermogravimetric analyses (TGA) conducted under isothermal and programmed heating conditions have shown that PILs with ?pK(a)? 15 exhibit good thermal stability similar to aprotic ionic liquids. For instance, PILs with ?pK(a) > 20 show remarkably high short-term thermal stability up to ca. 450 °C under a nitrogen atmosphere. The viscosity, ionic conductivity, and molar conductivity of the PILs fit well with the Vogel-Fulcher-Tamman equation for their dependencies on temperature. The relative cationic and anionic self-diffusion coefficients of the PILs estimated by the pulsed-field gradient spin-echo (PGSE) NMR method appear to be dependent on the structure and strength of the Brønsted acids. Evaluation of the ionicity based on both the Walden plot and PGSE-NMR revealed that it increases until ?pK(a) becomes 15 for the PILs. PMID:22415497

Miran, Muhammed Shah; Kinoshita, Hiroshi; Yasuda, Tomohiro; Susan, Md Abu Bin Hasan; Watanabe, Masayoshi

2012-04-21

192

Sonochemistry and sonoluminescence in ionic liquids, molten salts, and concentrated electrolyte solutions  

E-print Network

Review Sonochemistry and sonoluminescence in ionic liquids, molten salts, and concentrated interesting liquids for studies involving sonochemistry, acoustic cavitation, and sonoluminescence. Recent on the effects of cavitation on some room-temperature ionic liquids, including the sonoluminescence spectra

Suslick, Kenneth S.

193

Dynamics in Organic Ionic Liquids in Distinct Regions Using Charged and Uncharged Orientational Relaxation Probes  

E-print Network

, and therefore influence "task-specific" organic ionic liquids.13 The design of task-specific organic ionicDynamics in Organic Ionic Liquids in Distinct Regions Using Charged and Uncharged Orientational(trifluoromethanesulfonyl)imide (alkyl ) ethyl, butyl, hexyl, octyl) organic room temperature ionic liquids (RTIL). The two fluorescent

Fayer, Michael D.

194

Room Temperature Ionic Liquid-Lithium Salt Mixtures: Optical Kerr Effect Dynamical Measurements  

E-print Network

Room Temperature Ionic Liquid-Lithium Salt Mixtures: Optical Kerr Effect Dynamical Measurements to ionic liquids causes an increase in viscosity and a decrease in ionic mobility that hinders relaxation, caused by the addition of lithium bis(trifluoromethylsulfonyl)imide to the ionic liquid 1-butyl-3

Fayer, Michael D.

195

Electric field gating with ionic liquids Rajiv Misra, Mitchell McCarthy, and Arthur F. Hebarda  

E-print Network

Electric field gating with ionic liquids Rajiv Misra, Mitchell McCarthy, and Arthur F. Hebarda 2006; accepted 3 January 2007; published online 30 January 2007 The authors show that ionic liquids In this letter we report on the use of ionic liquids ILs rather than ionic fluid electrolytes as field gate

Hebard, Arthur F.

196

Adsorption of imidazolium and pyridinium ionic liquids onto montmorillonite : characterization and thermodynamic calculations  

E-print Network

1 Adsorption of imidazolium and pyridinium ionic liquids onto montmorillonite : characterization generation ionic liquids (RTILs : BMImCl, OMImCl, AMImCl, BPyBr and OPyBr) were intercalated into the layered: Montmorillonite; Ionic liquids; Adsorption; Thermodynamic parameters 1. Introduction Room Temperature Ionic

Paris-Sud XI, Université de

197

Ionic Liquid Catalyzed Electrolyte for Electrochemical Polyaniline Supercapacitors  

NASA Astrophysics Data System (ADS)

The effect of different wt.% of ionic liquid "1,6-bis (trimethylammonium-1-yl) hexane tetrafluoroborate" in 0.5 M LiClO4+PC electrolyte on the supercapacitor properties of polyaniline (PANI) thin film are investigated. The PANI film is synthesized using electropolymerization of aniline in the presence of sulfuric acid. The electrochemical properties of the PANI thin film are studied by cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy (EIS) measurements. The optimum amount of the ionic liquid is found to be 2 wt.% which provides better ionic conductivity of the electrolyte. The highest specific capacitance of 259 F/g is obtained using the 2 wt.% electrolyte. This capacitance remains at up to 208 F/g (80% capacity retention) after 1000 charge-discharge cycles at a current density of 0.5 mA/g. The PANI film in the 2 wt.% ionic liquid catalyzed 0.5 M LiClO4+PC electrolyte shows small electrochemical resistance, better rate performance and higher cyclability. The increased ionic conductivity of the 2 wt.% ionic liquid catalyzed electrolyte causes a reduction in resistance at the electrode/electrolyte interface, which can be useful in electrochemically-preferred power devices for better applicability.

Inamdar, A. I.; Im, Hyunsik; Jung, Woong; Kim, Hyungsang; Kim, Byungchul; Yu, Kook-Hyun; Kim, Jin-Sang; Hwang, Sung-Min

2013-05-01

198

Molecular solutes in ionic liquids: a structural perspective.  

PubMed

Understanding physicochemical properties of ionic liquids is important for their rational use in extractions, reactions, and other applications. Ionic liquids are not simple fluids: their ions are generally asymetric, flexible, with delocalized electrostatic charges, and available in a wide variety. It is difficult to capture their subtle properties with models that are too simplistic. Molecular simulation using atomistic force fields, which describe structures and interactions in detail, is an excellent tool to gain insights into their liquid-state organization, how they solvate different compounds, and what molecular factors determine their properties. The identification of certain ionic liquids as self-organized phases, with aggregated nonpolar and charged domains, provides a new way to interpret the solvation and structure of their mixtures. Many advances are the result of a successful interplay between experiment and modeling, possible in this field where none of the two methodologies had a previous advance. PMID:17661440

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

2007-11-01

199

Dissolution of cellulose in room temperature ionic liquids: anion dependence.  

PubMed

The dissolution of cellulosic biomass in room temperature ionic liquids (RTILs) is studied through free energy calculations of its monomer, viz., cellobiose, within a molecular dynamics simulation approach. The solvation free energy (SFE) of cellobiose in ionic liquids containing any of seven different anions has been calculated. The ranking of these liquids based on SFE compares well with experimental data on the solubility of cellulose. The dissolution is shown to be enthalpically dominated, which is correlated with the strength of intermolecular hydrogen bonding between cellobiose and the anions of the IL. Large entropic changes upon solvation in [CF3SO3](-) and [OAc](-) based ionic liquids have been explained in terms of the solvent-aided conformational flexibility of cellobiose. PMID:25535797

Payal, Rajdeep Singh; Bejagam, Karteek K; Mondal, Anirban; Balasubramanian, Sundaram

2015-01-29

200

THE JOURNAL OF CHEMICAL PHYSICS 139, 214701 (2013) The liquid surface of chiral ionic liquids as seen from molecular dynamics  

E-print Network

THE JOURNAL OF CHEMICAL PHYSICS 139, 214701 (2013) The liquid surface of chiral ionic liquids room-temperature ionic liquids (RTILs) derived from 1-n-butyl-3-methylimidazolium bromide ([bmim.1063/1.4833335] I. INTRODUCTION Room-temperature ionic liquids (RTILs) typically con- sist of bulky and asymmetric

Lisal, Martin

2013-01-01

201

Oligoether carboxylates: task-specific room-temperature ionic liquids.  

PubMed

Recently, a new family of ionic liquids based on oligoether carboxylates was introduced. 2,5,8,11-Tetraoxatridecan-13-oate (TOTO) was shown to form room-temperature ionic liquids (RTILs) even with small alkali ions such as lithium and sodium. However, the alkali TOTO salts suffer from their extremely high viscosities and relatively low conductivities. Therefore, we replaced the alkali cations by tetraalkylammonium (TAA) ions and studied the TOTO salts of tetraethyl- (TEA), tetrapropyl- (TPA), and tetrabutylammonium (TBA). In addition, the environmentally benign quaternary ammonium ion choline (Ch) was included in the series. All salts were found to be ionic liquids at ambient temperatures with a glass transition typically at around -60 °C. Viscosities, conductivities, solvent polarities, and Kamlet-Taft parameters were determined as a function of temperature. When using quaternary ammonium ions, the viscosities of the resulting TOTO ionic liquids are >600 times lower, whereas conductivities increase by a factor of up to 1000 compared with their alkali counterparts. Solvent polarities further reveal that choline and TAA cations yield TOTO ionic liquids that are more polar than those obtained with the, per se, highly polar sodium ion. Results are discussed in terms of ion-pairing and structure-breaking concepts with regard to a possible complexation ability of the TOTO anion. PMID:21682314

Klein, Regina; Zech, Oliver; Maurer, Eva; Kellermeier, Matthias; Kunz, Werner

2011-07-28

202

Task-specific ionic liquid for solubilizing metal oxides.  

PubMed

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

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

2006-10-26

203

Physicochemical properties and toxicities of hydrophobicpiperidinium and pyrrolidinium ionic liquids  

SciTech Connect

Some properties are reported for hydrophobic ionic liquids (IL) containing 1-methyl-1-propyl pyrrolidinium [MPPyrro]{sup +}, 1-methyl-1-butyl pyrrolidinium [MBPyrro]{sup +}, 1-methyl-1-propyl piperidinium [MPPip]{sup +}, 1-methyl-1-butyl piperidinium [MBPip]{sup +}, 1-methyl-1-octylpyrrolidinium [MOPyrro]{sup +} and 1-methyl-1-octylpiperidinium [MOPip]{sup +} cations. These liquids provide new alternatives to pyridinium and imidazolium ILs. High thermal stability of an ionic liquid increases safety in applications like rechargeable lithium-ion batteries and other electrochemical devices. Thermal properties, ionic conductivities, viscosities, and mutual solubilities with water are reported. In addition, toxicities of selected ionic liquids have been measured using a human cancer cell-line. The ILs studied here are sparingly soluble in water but hygroscopic. We show some structure-property relationships that may help to design green solvents for specific applications. While ionic liquids are claimed to be environmentally-benign solvents, as yet few data have been published to support these claims.

Salminen, Justin; Papaiconomou, Nicolas; Kumar, R. Anand; Lee,Jong-Min; Kerr, John; Newman, John; Prausnitz, John M.

2007-06-25

204

Alpha-chymotrypsin catalysis in imidazolium-based ionic liquids.  

PubMed

The transesterification reaction of N-acetyl-L-phenylalanine ethyl ester with 1-propanol catalyzed by alpha-chymotrypsin was examined in the ionic liquids 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF(6)]) and 1-octyl-3-methylimidazolium hexafluorophosphate ([omim][PF(6)]), and in combination with supercritical carbon dioxide (SC-CO(2)). The activity of alpha-chymotrypsin was studied to determine whether trends in solvent polarity, water activity, and enzyme support properties, observed with this enzyme in conventional organic solvents, hold for the novel environment provided by ionic liquids. alpha-Chymotrypsin freeze-dried with K(2)HPO(4), KCl, or poly(ethylene glycol) demonstrated no activity in [bmim][PF(6)] or [omim][PF(6)] at very low water concentrations, but moderate transesterification rates were observed with the ionic liquids containing 0.25% water (v/v) and higher. However, the physical complexation of the enzyme with poly(ethylene glycol) or KCl did not substantially stimulate activity in the ionic liquids, unlike that observed in hexane or isooctane. Activities were considerably higher in [omim][PF(6)] than [bmim][PF(6)]. Added water was not necessary for enzyme activity when ionic liquids were combined with SC-CO(2). These results indicate that [bmim][PF(6)] and [omim][PF(6)] provide a relatively polar environment, which can be modified with nonpolar SC-CO(2) to optimize enzyme activity. PMID:11536140

Laszlo, J A; Compton, D L

2001-10-20

205

Ionic conductivity of imidazole-functionalized liquid crystal mesogens  

NASA Astrophysics Data System (ADS)

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.

Roddecha, Supacharee; Anthamatten, Mitchell

2012-02-01

206

Trace element partitioning between ionic crystal and liquid  

NASA Technical Reports Server (NTRS)

The partitioning of trace elements between ionic crystals and the melt has been correlated with lattice energy of the host. The solid-liquid partition coefficient has been expressed in terms of the difference in relative ionic radius of the trace element and the homogeneous and heterogeneous strain of the host lattice. Predictions based on this model appear to be in general agreement with data for alkali nitrates and for rare-earth elements in natural garnet phenocrysts.

Tsang, T.; Philpotts, J. A.; Yin, L.

1978-01-01

207

Chromatographic and spectroscopic methods for the determination of solvent properties of room temperature ionic liquids  

Microsoft Academic Search

Room temperature ionic liquids are novel solvents with favorable environmental and technical features. Synthetic routes to over 200 room temperature ionic liquids are known but for most ionic liquids physicochemical data are generally lacking or incomplete. Chromatographic and spectroscopic methods afford suitable tools for the study of solvation properties under conditions that approximate infinite dilution. Gas–liquid chromatography is suitable for

Colin F. Poole

2004-01-01

208

From molten salts to room temperature ionic liquids: Simulation studies on chloroaluminate systems  

E-print Network

From molten salts to room temperature ionic liquids: Simulation studies on chloroaluminate systems chloride, which forms a room temperature ionic liquid EMI+ -AlCl- 4 . The structure yielded. INTRODUCTION When monovalent chloride salts are dissolved in liquid AlCl3, ionic liquids with low melting

Paris-Sud XI, Université de

209

Dynamics and structure of room temperature ionic liquids  

NASA Astrophysics Data System (ADS)

Room temperature ionic liquids (RTIL) are intrinsically interesting because they simultaneously have properties that are similar to organic liquids and liquid salts. In addition, RTILs are increasingly being considered for and used in technological applications. RTILs are usually composed of an organic cation and an inorganic anion. The organic cation, such as imidazolium, has alkyl chains of various lengths. The disorder in the liquid produced by the presence of the alkyl groups lowers the temperature for crystallization below room temperature and can also result in supercooling and glass formation rather than crystallization. The presence of the alkyl moieties also results in a segregation of the liquid into ionic and organic regions. In this article, experiments are presented that address the relationship between RTIL dynamics and structure. Time resolved fluorescence anisotropy measurements were employed to study the local environments in the organic and ionic regions of RTILs using a nonpolar chromophore that locates in the organic regions and an ionic chromophore that locates in the ionic regions. In the alkyl regions, the in plane and out of plane orientational friction coefficients change in different manners as the alkyl chains get longer. Both friction coefficients converge toward those of a long chain length hydrocarbon as the RTIL chains increase in length, which demonstrates that for sufficiently long alkyl chains the RTIL organic regions have properties similar to a hydrocarbon. However, putting Li+ in the ionic regions changes the friction coefficients in the alkyl regions, which demonstrates that changes of the ion structural organization influences the organization of the alkyl chains. Optical heterodyne detected optical Kerr effect (OHD-OKE) experiments were used to examine the orientational relaxation dynamics of RTILs over times scales of a hundred femtoseconds to a hundred nanoseconds. Detailed temperature dependent studies in the liquid and supercooled state and analysis using schematic mode coupling theory (MCT) show that RTILs have bulk liquid orientational relaxation dynamics that are indistinguishable in their nature from common nonpolar organic liquids that supercool. This behavior of the RTILs occurs in spite of the segregation into ionic and organic regions. However, when small amounts of water are added to RTILs at room temperature, novel dynamics are observed for the RTILs with long alkyl chains that have not been observed in OHD-OKE experiments on organic liquids. The results are interpreted as water induced structure in the ionic regions that causes the long alkyl chains to organize and 'lock up.' The dynamical measurements indicate that this lock up is involved in the formation of RTIL gels that occur over a narrow range of water concentrations.

Fayer, Michael D.

2014-11-01

210

A recyclable enzymatic biodiesel production process in ionic liquids.  

PubMed

Immobilized Candida antarctica lipase B suspended in ionic liquids containing long alkyl-chain cations showed excellent synthetic activity and operational stability for biodiesel production. The interest of this process lies in the possibility of recycling the biocatalyst and the easy separation of the biodiesel from the reaction mixture. The ionic liquids used, 1-hexadecyl-3-methylimidazolium triflimide ([C(16)MIM][NTf(2)]) and 1-octadecyl-3-methylimidazolium triflimide ([C(18)MIM][NTf(2)]), produced homogeneous systems at the start of the reaction and, at the end of the same, formed a three-phase system, allowing the selective extraction of the products using straightforward separation techniques, and the recycling of both the ionic liquid and the enzyme. These are very important advantages which may be found useful in environmentally friendly production conditions. PMID:21392972

De Diego, Teresa; Manjón, Arturo; Lozano, Pedro; Iborra, José L

2011-05-01

211

Methods for separating medical isotopes using ionic liquids  

DOEpatents

A method for extracting a radioisotope from an aqueous solution, the method comprising: a) intimately mixing a non-chelating ionic liquid with the aqueous solution to transfer at least a portion of said radioisotope to said non-chelating ionic liquid; and b) separating the non-chelating ionic liquid from the aqueous solution. In preferred embodiments, the method achieves an extraction efficiency of at least 80%, or a separation factor of at least 1.times.10.sup.4 when more than one radioisotope is included in the aqueous solution. In particular embodiments, the method is applied to the separation of medical isotopes pairs, such as Th from Ac (Th-229/Ac-225, Ac-227/Th-227), or Ra from Ac (Ac-225 and Ra-225, Ac-227 and Ra-223), or Ra from Th (Th-227 and Ra-223, Th-229 and Ra-225).

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

2014-10-21

212

Synthesis and properties of chiral ammonium-based ionic liquids.  

PubMed

New chiral ammonium-based ionic liquids containing the (1R,2S,5R)-(-)-menthyl group can be easily and efficiently prepared under ambient conditions. The preparation and characterization of trialkyl[(1R,2S,5R)-(-)-menthoxymethyl]ammonium salts is reported. The salts have been demonstrated to be air- and moisture-stable under ambient conditions and can be readily used in a variety of standard experimental procedures. The single-crystal X-ray structure of butyldimethyl[(1R,2S,5R)-(-)-menthoxymethyl]ammonium chloride has been determined. The chiral, room-temperature ionic liquids have been characterized by physical properties such as specific rotation, density, viscosity, thermal degradation, and glass transition temperature. Trialkyl[(1R,2S,5R)-(-)-menthoxymethyl]ammonium chloride prototype ionic liquids have also been found to exhibit strong antimicrobial and high antielectrostatic activities. PMID:15883984

Pernak, Juliusz; Feder-Kubis, Joanna

2005-07-18

213

Oscillating electrochemical reaction in copper-containing imidazolium ionic liquids.  

PubMed

An example of an electrochemical oscillator in ionic liquids is presented. Solutions of the ionic liquid 1-ethyl-3-methylimidazolium chloride, [C(2)mim]Cl, which contain both Cu(+) and Cu(2+) ions, show current oscillations during potentiostatic polarization. The oscillations were analyzed by the Quartz Crystal Microbalance (QCM) technique and by Electrochemical Impedance Spectroscopy (EIS). The electrochemical oscillations are of the N-NDR-type, because the low frequency end of the impedance spectrum has negative real impedances. The oscillating current leads to an oscillating growth speed of a metallic copper layer. Besides the presence of both Cu(+) and Cu(2+), the presence of chloride is a necessary, yet not a sufficient, condition for the occurrence of current oscillations. Oscillating currents were also observed for the ionic liquids 1-butyl-3-methylimidazolium chloride and 1-butyl-2,3-dimethylimidazolium chloride, but not for tributyltetradecylphosphonium chloride and N-butylpyridinium chloride. PMID:21808767

Schaltin, Stijn; Binnemans, Koen; Fransaer, Jan

2011-09-14

214

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

PubMed

A novel, simple, and environmentally friendly pretreatment method, ionic liquid magnetic bar liquid-phase microextraction, was developed for the determination of sulfonamides in butter samples by high-performance liquid chromatography. The ionic liquid magnetic bar was prepared by inserting a stainless steel wire into the hollow of a hollow fiber and immobilizing ionic liquid in the micropores of the hollow fiber. In the extraction process, the ionic liquid magnetic bars were used to stir the mixture of sample and extraction solvent and enrich the sulfonamides in the mixture. After extraction, the analyte-adsorbed ionic liquid magnetic bars were readily isolated with a magnet from the extraction system. It is notable that the present method was environmentally friendly since water and only several microliters of ionic liquid were used in the whole extraction process. Several parameters affecting the extraction efficiency were investigated and optimized, including the type of ionic liquid, sample-to-extraction solvent ratio, the number of ionic liquid magnetic bars, extraction temperature, extraction time, salt concentration, stirring speed, pH of the extraction solvent, and desorption conditions. The recoveries were in the range of 73.25-103.85 % and the relative standard deviations were lower than 6.84 %. The experiment results indicated that the present method was effective for the extraction of sulfonamides in high-fat content samples. PMID:25384336

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

2015-01-01

215

Kinetics and Solvent Effects in the Synthesis of Ionic Liquids  

E-print Network

and electrochemical applications. Langmuir 2005, 21, (20), 9000-9006. 4. Adedin, S. Z. E.; Polleth, M.; Meiss, S. A.; Janek, J.; Endres, F., Ionic liquids as green electrolytes for the electrodeposition of nanomaterials. Green Chem. 2007, 9, 549-553. 5. Barisci, J.... Synth. 2005, 2, (4), 437-451. 12. Zhang, X.; Fan, X.; Niu, H.; Wang, J., An ionic liquid as a recyclable medium for the green preparation of a,a'-bis (substituted benzylidene)cycloalkanones catalyzed by FeCl3*6H20. Green Chem. 2003, 5, 267-269. 13...

Schleicher, Jay C.

2007-12-12

216

Development of ionic liquid-based lithium battery prototypes  

Microsoft Academic Search

The lab-scale manufacturing of Li\\/LiFePO4 and Li4Ti5O12\\/LiFePO4 stacked battery prototypes and their performance characterization are described here. The prototypes were realized in the frame of an European Project devoted to the development of greener and safer lithium batteries, based on ionic liquid electrolytes, for integration with photovoltaic panels. N-Butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR14TFSI) and N-butyl-N-methylpyrrolidinium bis(fluoro-methanesulfonyl)imide (PYR14FSI), selected as the ionic liquids

G.-T. Kim; S. S. Jeong; M.-Z. Xue; A. Balducci; M. Winter; S. Passerini; F. Alessandrini; G. B. Appetecchi

217

Capturing CO2: conventional versus ionic-liquid based technologies  

NASA Astrophysics Data System (ADS)

Since CO2 facilitates pipeline corrosion and contributes to a decrease of the calorific value of gaseous fuels, its removal has become an issue of significant economic importance. The present review discusses various types of traditional CO2 capture technologies in terms of their efficiency, complexity in system design, costs and environmental impact. The focus is hereby not only on conventional approaches but also on emerging "green" solvents such as ionic liquids. The suitability of different ionic liquids as gas separation solvents is discussed in the present review and a description on their synthesis and properties in terms of CO2 capture is provided. The bibliography includes 136 references.

Privalova, E. I.; Mäki-Arvela, P.; Murzin, Dmitry Yu; Mikkhola, J. P.

2012-05-01

218

Hydrolysis and Partial Recycling of a Chloroaluminate Ionic Liquid  

PubMed Central

Hydrolysis of the ionic liquid Et3NHCl-2AlCl3 and a process for recycling the triethylamine were studied. When the hydrolysis was carried out at a relatively high temperature, the released HCl could be absorbed more easily. With addition of sodium hydroxide to the aqueous hydrolysis solution, a feasible process for recycling triethylamine was developed, involving first distillation of triethylamine, followed by filtration of the aluminium hydroxide. The yield of recovered triethylamine was about 95%. The triethylhydrogenammonium chloride prepared from the recycled triethylamine was of good purity and could be reused to synthesize new chloroaluminate ionic liquids.

Fang, Ming-Hong; Wang, Li-Sheng

2007-01-01

219

Energy Efficient Electrochromic Windows Incorporating Ionic Liquids  

SciTech Connect

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.

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

2008-11-30

220

A new ionic liquid based quasi-solid state electrolyte for dye-sensitized solar cells  

Microsoft Academic Search

Ionic liquid based quasi-solid state electrolytes were prepared by solidifying the ionic liquid electrolytes containing 1-hexyl-3-methylidazolium iodide (HMImI) or a binary mixture of HMImI and 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF4) with an ionic liquid polymer poly (1-oligo (ethylene glycol) methacrylate-3-methylimidazolium chloride) (P(MOEMImCl)), respectively. The improvements of the ionic conductivity and the apparent diffusion coefficient of triiodide are observed in the binary ionic

Miao Wang; Xong Yin; Xu Rui Xiao; XiaoWen Zhou; Zheng Zhong Yang; Xue Ping Li; Yuan Lin

2008-01-01

221

Low Temperature Reduction of Alumina Using Fluorine Containing Ionic Liquids  

SciTech Connect

The major objective of the project is to establish the feasibility of using specific ionic liquids capable of sustaining aluminum electrolysis near room temperature at laboratory and batch recirculation scales. It will explore new technologies for aluminum and other valuable metal extraction and process methods. The new technology will overcome many of the limitations associated with high temperatures processes such as high energy consumption and corrosion attack. Furthermore, ionic liquids are non-toxic and could be recycled after purification, thus minimizing extraction reagent losses and environmental pollutant emissions. Ionic liquids are mixture of inorganic and organic salts which are liquid at room temperature and have wide operational temperature range. During the last several years, they were emerging as novel electrolytes for extracting and refining of aluminum metals and/or alloys, which are otherwise impossible using aqueous media. The superior high temperature characteristics and high solvating capabilities of ionic liquids provide a unique solution to high temperature organic solvent problems associated with device internal pressure build-up, corrosion, and thermal stability. However their applications have not yet been fully implemented due to the insufficient understanding of the electrochemical mechanisms involved in processing of aluminum with ionic liquids. Laboratory aluminum electrodeposition in ionic liquids has been investigated in chloride and bis (trifluoromethylsulfonyl) imide based ionic liquids. The electrowinning process yielded current density in the range of 200-500 A/m2, and current efficiency of about 90%. The results indicated that high purity aluminum (>99.99%) can be obtained as cathodic deposits. Cyclic voltammetry and chronoamperometry studies have shown that initial stages of aluminum electrodeposition in ionic liquid electrolyte at 30°C was found to be quasi-reversible, with the charge transfer coefficient (0.40). Nucleation phenomena involved in aluminum deposition on copper in AlCl3-BMIMCl electrolyte was found to be instantaneous followed by diffusion controlled three-dimensional growth of nuclei. Diffusion coefficient (Do) of the electroactive species Al2Cl7¯ ion was in the range from 6.5 to 3.9×10–7 cm2?s–1 at a temperature of 30°C. Relatively little research efforts have been made toward the fundamental understanding and modeling of the species transport and transformation information involved in ionic liquid mixtures, which eventually could lead to quantification of electrochemical properties. Except that experimental work in this aspect usually is time consuming and expensive, certain characteristics of ionic liquids also made barriers for such analyses. Low vapor pressure and high viscosity make them not suitable for atomic absorption spectroscopic measurement. In addition, aluminum electrodeposition in ionic liquid electrolytes are considered to be governed by multi-component mass, heat and charge transport in laminar and turbulent flows that are often multi-phase due to the gas evolution at the electrodes. The kinetics of the electrochemical reactions is in general complex. Furthermore, the mass transfer boundary layer is about one order of magnitude smaller than the thermal and hydrodynamic boundary layer (Re=10,000). Other phenomena that frequently occur are side reactions and temperature or concentration driven natural convection. As a result of this complexity, quantitative knowledge of the local parameters (current densities, ion concentrations, electrical potential, temperature, etc.) is very difficult to obtain. This situation is a serious obstacle for improving the quality of products, efficiency of manufacturing and energy consumption. The gap between laboratory/batch scale processing with global process control and nanoscale deposit surface and materials specifications needs to be bridged. A breakthrough can only be realized if on each scale the occurring phenomena are understood and quantified. Multiscale numerical modeling nevertheless can help t

Dr. R. G. Reddy

2007-09-01

222

Ultrafast solvation response in room temperature ionic liquids: Possible origin and importance of the collective and the nearest neighbour solvent  

E-print Network

Ultrafast solvation response in room temperature ionic liquids: Possible origin and importance OF CHEMICAL PHYSICS 137, 114501 (2012) Ultrafast solvation response in room temperature ionic liquids temperature ionic liquids (RTILs) have revealed multi-exponential dynamics with ultrafast solvation timescale

Biswas, Ranjit

223

HOMOGENEOUS CATALYSIS AND MASS TRANSFER IN BIPHASIC IONIC LIQUID SYSTEMS WITH COMPRESSED CO2 AND ORGANIC COMPOUNDS  

E-print Network

) of ionic liquids can be managed by either the structure of ionic liquids or the pressure of various compressed gases. Thus, the measured and correlated results of viscosities and diffusivities for pure and saturated of different types of ionic liquids...

Ahosseini, Azita

224

Charge Transport and Glassy Dynamics in Ionic Liquids  

SciTech Connect

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.

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

2012-01-01

225

Ionic liquid dispersive liquid–liquid microextraction of lead as pyrrolidinedithiocarbamate chelate prior to its flame atomic absorption spectrometric determination  

Microsoft Academic Search

A novel separation–preconcentration procedure based on ionic liquid dispersive liquid–liquid microextraction of traces lead as pyrrolidinedithiocarbamate chelate has been developed. 1-Hexyl-3-methylimidazolium hexafluorophosphate as ionic liquid was used for extraction of lead pyrrolidinedithiocarbamate chelate. After phase separation, the enriched analyte in the final solution is determined by flame atomic absorption spectrometry (FAAS). The effects of pH, amounts of ligand, amounts of

Mustafa Soylak; Erkan Yilmaz

2011-01-01

226

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

E-print Network

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 ...

Fedkiw, Timothy Peter

2010-01-01

227

Synthesis of fluoromethylated materials derived from 2-trifluoromethyl acrylic acid phenethyl ester in an ionic liquid  

Microsoft Academic Search

Synthesis of fluoromethylated materials via Michael addition reaction catalyzed by l-proline in an ionic liquid, is described. Further, the synthesis and synthetic application of zinc reagents generated in an ionic liquid, giving trifluoromethylated materials, are described.

Abdellatif M Salaheldin; Zhao Yi; Tomoya Kitazume

2004-01-01

228

Fabrication of fiber supported ionic liquids and methods of use  

DOEpatents

One or more embodiments relates to the production of a fabricated fiber having an asymmetric polymer network and having an immobilized liquid such as an ionic liquid within the pores of the polymer network. The process produces the fabricated fiber in a dry-wet spinning process using a homogenous dope solution, providing significant advantage over current fabrication methods for liquid-supporting polymers. The fabricated fibers may be effectively utilized for the separation of a chemical species from a mixture based on the selection of the polymer, the liquid, and the solvent utilized in the dope.

Luebke, David R; Wickramanayake, Shan

2013-02-26

229

Dynamic wetting of a fluoropolymer surface by ionic liquids.  

PubMed

The spontaneous spreading of ionic liquids on a fluoropolymer surface (Teflon AF1600) in air is investigated by high-speed video microscopy. Six ionic liquids (EMIM BF(4), BMIM BF(4), OMIM BF(4), EMIM NTf(2), BMIM NTf(2) and HMIM NTf(2)) are used as probe liquids. The dependence of the dynamic contact angle on contact line velocity is interpreted with a hydrodynamic model and a molecular-kinetic model. The usefulness of the hydrodynamic model is rather limited. There is a good correspondence between the molecular dimensions of the liquids and the physical parameters of the molecular-kinetic model. The viscous and molecular-kinetic contributions to energy dissipation are calculated, revealing that energy is dissipated in the bulk as well as at the contact line during dynamic wetting. There are wide ramifications of these results in areas ranging from lubrication and biology to minerals processing and petroleum recovery. PMID:21240433

Li, Hua; Sedev, Rossen; Ralston, John

2011-03-01

230

Thermodynamics of micellization of imidazolium ionic liquids in aqueous solutions.  

PubMed

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

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

2009-08-01

231

Fission-Product Separation Based on Room-Temperature Ionic Liquids  

SciTech Connect

The objectives of this project are (a) to synthesize new ionic liquids tailored for the extractive separation of Cs + and Sr 2+; (b) to select optimum macrocyclic extractants through studies of complexation of fission products with macrocyclic extractants and transport in new extraction systems based on ionic liquids; (c) to develop efficient processes to recycle ionic liquids and crown ethers; and (d) to investigate chemical stabilities of ionic liquids under strong acid, strong base, and high-level-radiation conditions.

Luo, Huimin; Hussey, Charles L.

2005-09-30

232

Fission-Product Separation Based on Room-Temperature Ionic Liquids  

SciTech Connect

The objectives of this project are (a) to synthesize new ionic liquids tailored for the extractive separation of Cs + and Sr 2+; (b) to select optimum macrocyclic extractants through studies of complexation of fission products with macrocyclic extractants and transport in new extraction systems based on ionic liquids; (c) to develop efficient processes to recycle ionic liquids and crown ethers; and (d) to investigate chemical stabilities of ionic liquids under strong acid, strong base, and high-level-radiation conditions.

Luo, Huimin

2006-11-15

233

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

Microsoft Academic Search

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

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

2010-01-01

234

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

Microsoft Academic Search

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

Johnathan Gorke; Friedrich Srienc; Romas Kazlauskas

2010-01-01

235

Robust and versatile ionic liquid microarrays achieved by microcontact printing.  

PubMed

Lab-on-a-chip and miniaturized systems have gained significant popularity motivated by marked differences in material performance at the micro-to-nano-scale realm. However, to fully exploit micro-to-nano-scale chemistry, solvent volatility and lack of reproducibility need to be overcome. Here, we combine the non-volatile and versatile nature of ionic liquids with microcontact printing in an attempt to establish a facile protocol for high throughput fabrication of open microreactors and microfluidics. The micropatterned ionic liquid droplets have been demonstrated as electrochemical cells and reactors for microfabrication of metals and charge transfer complexes, substrates for immobilization of proteins and as membrane-free high-performance amperometric gas sensor arrays. The results suggest that miniaturized ionic liquid systems can be used to solve the problems of solvent volatility and slow mass transport in viscous ionic liquids in lab-on-a-chip devices, thus providing a versatile platform for a diverse number of applications. PMID:24781644

Gunawan, Christian A; Ge, Mengchen; Zhao, Chuan

2014-01-01

236

Preparation of mesoporous aluminum hydroxide and oxide in ionic liquids  

Microsoft Academic Search

Mesoporous aluminum hydroxides and oxides were synthesized using ionic liquids (ILs) as templates. The influence of various\\u000a factors (the nature of the IL, pH, ultrasonication, surfactants, reagent ratio, and the nature of the aluminum precursor)\\u000a on the specific surface area and pore volume was analyzed.

L. A. Aslanov; M. A. Zakharov; E. E. Knyazeva; A. V. Yatsenko

2007-01-01

237

Low Temperature Reduction of Alumina Using Fluorine Containing Ionic Liquids  

Microsoft Academic Search

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

R. G. Reddy

2007-01-01

238

High performance ultracapacitors with carbon nanomaterials and ionic liquids  

DOEpatents

The present invention is directed to the use of carbon nanotubes and/or electrolyte structures in various electrochemical devices, such as ultracapacitors having an ionic liquid electrolyte. The carbon nanotubes are preferably aligned carbon nanotubes. Compared to randomly entangled carbon nanotubes, aligned carbon nanotubes can have better defined pore structures and higher specific surface areas.

Lu, Wen; Henry, Kent Douglas

2012-10-09

239

Method for synthesis of titanium dioxide nanotubes using ionic liquids  

DOEpatents

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.

Qu, Jun; Luo, Huimin; Dai, Sheng

2013-11-19

240

Environmental fate and toxicity of ionic liquids: A review  

Microsoft Academic Search

Ionic liquids (ILs) are organic salts with low melting point that are being considered as green replacements for industrial volatile organic compounds. The reputation of these solvents as “environmental friendly” chemicals is based primarily on their negligible vapor pressure. Nonetheless, the solubility of ILs in water and a number of literature documenting toxicity of ILs to aquatic organisms highlight a

Thi Phuong Thuy Pham; Chul-Woong Cho; Yeoung-Sang Yun

2010-01-01

241

High performance batteries with carbon nanomaterials and ionic liquids  

DOEpatents

The present invention is directed to lithium-ion batteries in general and more particularly to lithium-ion batteries based on aligned graphene ribbon anodes, V.sub.2O.sub.5 graphene ribbon composite cathodes, and ionic liquid electrolytes. The lithium-ion batteries have excellent performance metrics of cell voltages, energy densities, and power densities.

Lu, Wen (Littleton, CO)

2012-08-07

242

Task specific ionic liquid for direct electrochemistry of metal oxides  

Microsoft Academic Search

We present the first report on task specific ionic liquid (TSIL) for direct electrochemical detection of heavy metal oxides including cadmium oxide, copper oxide and lead oxide at room temperature. This TSIL based electrochemical sensor demonstrated a high sensitivity and selectivity towards the online monitoring of these trace metal oxide particulates, along with short detection time, low cost and high

Donglai Lu; Nasim Shomali; Amy Shen

2010-01-01

243

Sulfonium-based Ionic Liquids Incorporating the Allyl Functionality  

PubMed Central

A series of sulfonium halides bearing allyl groups have been prepared and characterized. Anion metathesis with Li[Tf2N] and Ag[N(CN)2] resulted in sulfonium-based ionic liquids which exhibit low viscosities at room temperature. The solid state structure of one of the halide salts was determined by single crystal X-ray diffraction.

Zhao, Dongbin; Fei, Zhaofu; Ang, Wee Han; Dyson, Paul J.

2007-01-01

244

Lunar Oxygen Production and Metals Extraction Using Ionic Liquids  

NASA Technical Reports Server (NTRS)

Initial results indicate that ionic liquids are promising media for the extraction of oxygen from lunar regolith. IL acid systems can solubilize regolith and produce water with high efficiency. IL electrolytes are effective for water electrolysis, and the spent IL acid media are capable of regeneration.

Marone, Matthew; Paley, Mark Steven; Donovan, David N.; Karr, Laurel J.

2009-01-01

245

EVALUATING THE GREENNESS OF IONIC LIQUIDS VIA LIFE CYCLE ASSESSMENT  

EPA Science Inventory

Ionic Liquids have been suggested as "greener" replacements to traditional solvents. However, the environmental impacts of the life cycle phases have not been studied. Such a "cradle to gate" Life Cycle Assessment (LCA) for comparing the environmental impact of various solvents...

246

EXPEDITIOUS SOLVENT-FREE PREPARATION OF IONIC LIQUIDS USING MICROWAVES  

EPA Science Inventory

Ambient temperature ionic liquids comprising 1,3-dialkylimidazolium cations have shown great promise as alternative solvents in view of their negligible vapor pressure, ease of handling and potential for recycling. An efficient solventless protocol for the preparation of a wide v...

247

Unexpected Preferential Dehydration of Artemisinin in Ionic Liquids  

NASA Astrophysics Data System (ADS)

Thermodynamic measurements (at 298 K) reveal that a crucial step in the extraction process of the key antimalarial drug artemisinin by ionic liquids (ILs), namely, precipitation through the addition of water, is driven by artemisinin dehydration due to the differences in the water's interaction with the bulk ILs, rather than with the artemisinin itself.

Sanders, Marc W.; Wright, Lawrence; Tate, Lauren; Fairless, Gayle; Crowhurst, Lorna; Bruce, Neil C.; Walker, Adam J.; Hembury, Guy A.; Shimizu, Seishi

2009-09-01

248

Hydrolysis of cellulose catalyzed by novel acidic ionic liquids.  

PubMed

The conversion of cellulosic biomass directly into valuable chemicals becomes a hot subject. Six novel acidic ionic liquids (ILs) based on 2-phenyl-2-imidazoline were synthesized and characterized by UV-VIS, TGA, and NMR. The novel acidic ionic liquids were investigated as catalysts for the hydrolysis of cellulose in 1-butyl-3-methylimidazolium chloride ([Bmim]Cl). The acidic ionic liquids with anions HSO4(-) and Cl(-) showed better catalytic performance for the hydrolysis of cellulose than those with H2PO4(-). The temperature and dosage of water affect significantly the yield of total reducing sugar (TRS). When the hydrolysis of cellulose was catalyzed by 1-propyl sulfonic acid-2-phenyl imidazoline hydrogensulfate (IL-1) and the dosage of water was 0.2g, the TRS yield was up to 85.1% within 60 min at 100°C. These new acidic ionic liquids catalysts are expected to have a wide application in the conversion of cellulose into valuable chemicals. PMID:25439867

Zhuo, Kelei; Du, Quanzhou; Bai, Guangyue; Wang, Congyue; Chen, Yujuan; Wang, Jianji

2015-01-22

249

Water immiscible ionic liquids as solvents for whole cell biocatalysis  

Microsoft Academic Search

Whole cell biocatalysis can effectively be used for the production of enantiomerically pure compounds, but efficiency is often low. Toxicity and poor solubility of substrates and products are the main obstacles. In this study, water immiscible ionic liquids are shown to have no damaging effects on the cell membranes of Escherichia coli and Saccharomyces cerevisiae. Thus, they can be used

Holger Pfruender; Ross Jones; Dirk Weuster-Botz

2006-01-01

250

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,...

251

Physical Properties of Ionic Liquids: Database and Evaluation  

Microsoft Academic Search

A comprehensive database on physical properties of ionic liquids (ILs), which was collected from 109 kinds of literature sources in the period from 1984 through 2004, has been presented. There are 1680 pieces of data on the physical properties for 588 available ILs, from which 276 kinds of cations and 55 kinds of anions were extracted. In terms of the

Suojiang Zhang; Ning Sun; Xuezhong He; Xingmei Lu; Xiangping Zhang

2006-01-01

252

SOLVENT-FREE SONOCHEMICAL PREPARATION OF IONIC LIQUIDS  

EPA Science Inventory

An ultrasound-assisted preparation of a series of ambient temperature ionic liquids, 1-alkyl-3-methylimidazolium (AMIM) halides, that proceeds via efficient reaction of 1-methyl imidazole with alkyl halides/terminal dihalides under solvent-free conditions, is described. ...

253

Reaction kinetics of CO2 absorption in to phosphonium based anion-functionalized ionic liquids.  

PubMed

The reaction kinetics between CO2 and trihexyl(tetradecyl)phosphonium ([P66614])-based ionic liquids (ILs) with prolinate ([Pro]), 2-cyanopyrrolide ([2-CNpyr]), and 3-(trifluoromethyl)pyrazolide ([3-CF3pyra]) anions are studied at temperatures from 22-60 °C. The absorption of CO2 is carried out in a stirred reactor under pseudo first order conditions. ILs are diluted to concentrations of 0.05, 0.1 and 0.15 M with tetraglyme--a nonreactive, low volatility solvent with much lower viscosity than the ILs. Physical solubility of CO2 in the mixtures is calculated using correlations developed from CO2 solubility measurements in tetraglyme and the N2O-analogy for ILs and dilute IL solutions. The diffusivity of CO2 is estimated from viscosity-dependent correlations chosen after a thorough literature review. The results indicate partial first order reaction kinetics with respect to IL with values ranging from 19,500 L mol(-1) s(-1) ([P66614][Pro]) to 3200 L mol(-1) s(-1) ([P66614][3-CF3pyra]) at 22 °C. The second order reaction rate constants follow Arrhenius behavior with the highest activation energy of 43 kJ mol(-1) measured for [P66614][Pro]. ILs with aprotic heterocylic anions (AHA), on the other hand, show small activation energies of 18 and 11 kJ mol(-1) for [P66614][3-CF3pyra] and [P66614][2-CNpyr], respectively. The ILs studied in this work exhibit reactivity comparable to or higher than common aqueous amines. High reaction rates and tunable capacity make ILs, and AHA ILs in particular, attractive solvents for CO2 separations. PMID:23598368

Gurkan, Burcu E; Gohndrone, Thomas R; McCready, Mark J; Brennecke, Joan F

2013-05-28

254

Development of safe, green and high performance ionic liquids-based batteries (ILLIBATT project)  

Microsoft Academic Search

This manuscript presents the work carried out within the European project ILLIBATT, which was dedicated to the development of green, safe and high performance ionic liquids-based lithium batteries. Different types of ionic liquids-based electrolytes were developed in the project, based on different ionic liquids and polymers. Using these electrolytes, the performance of several anodic and cathodic materials has been tested

A. Balducci; S. S. Jeong; G. T. Kim; S. Passerini; M. Winter; M. Schmuck; G. B. Appetecchi; R. Marcilla; D. Mecerreyes; V. Barsukov; V. Khomenko; I. Cantero; I. De Meatza; M. Holzapfel; N. Tran

2011-01-01

255

Convenient and efficient protocols for coumarin synthesis via Pechmann condensation in neutral ionic liquids  

Microsoft Academic Search

Neutral ionic liquids with catalytic amount of acid have been employed for coumarin synthesis via Pechmann condensation of phenols and ethyl acetoacetate under ambient conditions. The reaction was also successfully carried out at high temperature in 1-butyl-3-methylimidazolium hexafluorophosphate ionic liquid, without the use of any acid catalyst. The possibility of Brönsted acidic ionic liquids catalysing this reaction has also been

Mahesh K. Potdar; Meghana S. Rasalkar; Swapnil S. Mohile; Manikrao M. Salunkhe

2005-01-01

256

An ionic liquid influenced l-proline catalysed asymmetric Michael addition of ketones to nitrostyrene  

Microsoft Academic Search

l-Proline in ionic liquid was employed for Michael addition of ketones to nitrostyrene. Optically active ?-nitroketones were obtained in good yields up to 80%. The reaction offers high syn selectivity (90%). The most striking feature is that the ionic liquid has been found to enhance the enantioselectivity, wherein enantiomeric excess approaches 75%. The system of ionic liquid and catalyst has

Meghana S. Rasalkar; Mahesh K. Potdar; Swapnil S. Mohile; Manikrao M. Salunkhe

2005-01-01

257

Development of a Native Escherichia coli Induction System for Ionic Liquid Tolerance  

E-print Network

Development of a Native Escherichia coli Induction System for Ionic Liquid Tolerance Marijke lignocellulose makes certain ionic liquids (ILs) very effective reagents for pretreating biomass prior to its for Ionic Liquid Tolerance. PLoS ONE 9(7): e101115. doi:10.1371/journal.pone.0101115 Editor: John R

Dunlop, Mary

258

Imaging an ionic liquid adlayer by scanning tunneling microscopy at the solid|vacuum interface  

E-print Network

Imaging an ionic liquid adlayer by scanning tunneling microscopy at the solid|vacuum interface T of an ionic liquid on a single crystalline Au(111) surface by scanning tun- neling microscopy (STM) under in the gas phase. Keywords: Ionic liquids, Adsorption, Structure, Scanning tunneling microscopy, Ultra

Pfeifer, Holger

259

An Insight of Combustibility Induced Safety Issues Pertaining to Ionic Liquids  

E-print Network

An Insight of Combustibility Induced Safety Issues Pertaining to Ionic Liquids Diallo, A.O.1 is a consolidated overview on explosion and fire safety issues pertaining to ionic liquids. Indeed safety performance of ionic liquids relating to physico-chemical hazards is very rarely investigated as it is often

Paris-Sud XI, Université de

260

The Use of Ionic Liquid Ion Sources (ILIS) in FIB Applications  

E-print Network

The Use of Ionic Liquid Ion Sources (ILIS) in FIB Applications Anthony Nicholas Zorzos June 2009 SSL #7-09 #12;#12;The Use of Ionic Liquid Ion Sources (ILIS) in FIB Applications Anthony Nicholas Use of Ionic Liquid Ion Sources (ILIS) in FIB Applications by Anthony Nicholas Zorzos Submitted

261

The Influence of Lithium Cations on Dynamics and Structure of Room Temperature Ionic Liquids  

E-print Network

The Influence of Lithium Cations on Dynamics and Structure of Room Temperature Ionic Liquids ionic liquid (RTIL) 1-butyl-3-methylimida- zolium bis(trifluoromethyl)sulfonyl imide were studied the structure of the alkyl regions of the RTIL. I. INTRODUCTION Room temperature ionic liquids (RTIL) have

Fayer, Michael D.

262

Physicochemical properties of 1,2,3-triazolium ionic liquids{ Shilpi Sanghi,a  

E-print Network

Physicochemical properties of 1,2,3-triazolium ionic liquids{ Shilpi Sanghi,a Erik Willett,a Craig: 10.1039/c1ra00286d Ionic liquids composed of four different 1,2,3-triazolium cations with tosylate liquids including ion cluster behavior, thermal properties, electrochemical stability and ionic

263

Influence of Water on Diffusion in Imidazolium-Based Ionic Liquids by NMR  

E-print Network

Influence of Water on Diffusion in Imidazolium-Based Ionic Liquids by NMR Sergey Vasenkov AMRIS-ethyl-3- methylimidazolium-based ionic liquids. This technique combines advantages of high field (17.6 T recording of an NMR signal from small amounts of water added to the ionic liquids. Using high gradients

264

Probing the Interface of Charged Surfactants in Ionic Liquids by XPS  

E-print Network

Chapter 14 Probing the Interface of Charged Surfactants in Ionic Liquids by XPS Lang G. Chen behavior in multi-component ionic liquid systems. © 2012 American Chemical Society Downloadedby In Ionic Liquids: Science and Applications; Visser, A., et al.; ACS Symposium Series; American Chemical

265

Ionic Liquid Ion Source Emitter Arrays Fabricated on Bulk Porous Substrates for Spacecraft Propulsion  

E-print Network

Ionic Liquid Ion Source Emitter Arrays Fabricated on Bulk Porous Substrates for Spacecraft Propulsion Daniel George Courtney, Paulo Lozano June 2011 SSL # 9-11 #12;#12;Ionic Liquid Ion Source Emitter;Ionic Liquid Ion Source Emitter Arrays Fabricated on Bulk Porous Substrates for Spacecraft Propulsion

266

WHEN IT COMES TO SOLVENTS, IONIC LIQUIDS are in a class by themselves. Compared to other  

E-print Network

WHEN IT COMES TO SOLVENTS, IONIC LIQUIDS are in a class by themselves. Compared to other solvents, nanotechnology and environmen- tal remediation. Ionic liquids are exceptionally potent as well. Research to date of ionic liquid can be made from a very renewable natural resource -- pine trees. "The potential

Bieber, Michael

267

Monodisperse Polymeric Ionic Liquid Microgel Beads with Multiple Chemically Switchable Functionalities  

E-print Network

Monodisperse Polymeric Ionic Liquid Microgel Beads with Multiple Chemically Switchable monodisperse poly(ionic liquid) microgel beads with a multitude of functionalities that can be chemically addressed sensing. INTRODUCTION Ionic liquids are salts of an organic cation (e.g., ammonium, imidazolium

Doyle, Patrick S.

268

Stokes Shift Dynamics in Ionic Liquids: Temperature Dependence Hemant K. Kashyap and Ranjit Biswas*  

E-print Network

Stokes Shift Dynamics in Ionic Liquids: Temperature Dependence Hemant K. Kashyap and Ranjit Biswas dependence of the dynamic fluorescence Stokes shift of a dipolar solute in seven imidazolium ionic liquids between fluorescence spectral dynamics and dielectric relaxation in ionic liquids. The slope

Biswas, Ranjit

269

Dipolar Solvation Dynamics in Room Temperature Ionic Liquids: An Effective Medium Calculation Using Dielectric Relaxation Data  

E-print Network

Dipolar Solvation Dynamics in Room Temperature Ionic Liquids: An Effective Medium Calculation Using to a laser-excited probe molecule in an ionic liquid is approximated by that in an effective dipolar medium, no probe dependence has been found for the average solvation times in these ionic liquids. In addition

Biswas, Ranjit

270

Effect of ionic liquids on epoxide hydrolase-catalyzed synthesis of chiral Cinzia Chiappe,*a  

E-print Network

Effect of ionic liquids on epoxide hydrolase-catalyzed synthesis of chiral 1,2-diols Cinzia Chiappe Ionic liquids (ILs) offer new possibilities for epoxide hydrolase (EH) catalyzed resolution of epoxides and enantioselective manner in some ionic liquids (ILs),12 although organic solvents (e.g. methyl tert-butyl ether

Hammock, Bruce D.

271

Short Communication Bioreduction and precipitation of uranium in ionic liquid aqueous  

E-print Network

Short Communication Bioreduction and precipitation of uranium in ionic liquid aqueous solution t s Uranium forms various complexes with ionic liquids. Uranium bioreduction was affected by the type of complex formed with ionic liquid. Precipitation of reduced uranium was retarded in the presence

Ohta, Shigemi

272

AN ELECTROSTATIC INTERPRETATION OF STRUCTURE-PROPERTY RELATIONSHIPS IN IONIC LIQUIDS  

E-print Network

AN ELECTROSTATIC INTERPRETATION OF STRUCTURE-PROPERTY RELATIONSHIPS IN IONIC LIQUIDS Mark N. Kobrak University of New York 2900 Bedford Ave. Brooklyn, NY 11210 ABSTRACT Room-temperature ionic liquids represent in molecular liquid theory, that of a molecular dipole moment, is in fact ill-defined for ionic materials

Kobrak, Mark N.

273

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

E-print Network

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 ionic liquids (RTIL), such as 1-butyl-3- methylimidazolium hexafluorophosphate (BmImPF6), are salts

Fayer, Michael D.

274

Computer simulations of ionic liquids at electrochemical interfaces C. Merlet1,2  

E-print Network

Computer simulations of ionic liquids at electrochemical interfaces C. Merlet1,2 , B. Rotenberg1 for a given applied potential, which is the relevant quantity for the highly topical use of ionic liquids structure for all ionic liquids at the surface of planar electrodes. This organization cannot take place

Paris-Sud XI, Université de

275

Double Layer in Ionic Liquids: Overscreening versus Crowding Martin Z. Bazant,1  

E-print Network

Double Layer in Ionic Liquids: Overscreening versus Crowding Martin Z. Bazant,1 Brian D. Storey,2 of solvent-free ionic liquids and use it to predict the structure of the electrical double layer. The model simulations and experiments on room-temperature ionic liquids, using a correlation length of order the ion

Bazant, Martin Z.

276

Dimerization of ion radicals in ionic liquids. An example of favourable ``Coulombic'' solvationw  

E-print Network

Dimerization of ion radicals in ionic liquids. An example of favourable ``Coulombic'' solvationw,2,3-trialkylimidazolium ionic liquids. Indeed, such ion dimerizations which display slow kinetics despite small activation'' in imidazolium-based ionic liquids, a strong interaction between the negatively- charged intermediates

Paris-Sud XI, Université de

277

Ionic liquid-modulated synthesis of ferrimagnetic Fe3S4 hierarchical superstructuresw  

E-print Network

Ionic liquid-modulated synthesis of ferrimagnetic Fe3S4 hierarchical superstructuresw Jianmin Ma hierarchical micro- spheres have been fabricated via an ionic liquid-modulated solution­phase process­controlled synthesis of inorganic nanomaterials with higher complexity. Recently, ionic liquids (ILs) have attracted

Utrecht, Universiteit

278

Erratum: Double Layer in Ionic Liquids: Overscreening versus Crowding [Phys. Rev. Lett. 106, 046102 (2011)  

E-print Network

Erratum: Double Layer in Ionic Liquids: Overscreening versus Crowding [Phys. Rev. Lett. 106, 046102 short-range Coulomb correlations and ion exclusion effects in the ionic liquid, as a step towards a more as in the bulk ionic liquid. This procedure serves its purpose, providing additional reduction of capacitance

Bazant, Martin Z.

2011-01-01

279

A NEW CLASS OF SOLVENTS FOR TRU DISSOLUTION AND SEPARATION: IONIC LIQUIDS  

EPA Science Inventory

This report focuses on the progress of a study of a New Class of Solvents for TRU Dissolution and Separation: Ionic Liquids. Key research issues are: (1) examining Cs, Sr, Tc, and TRU partitioning in Ionic Liquid/aqueous systems; (2) developing new Ionic Liquids for TRU separat...

280

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

Microsoft Academic Search

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

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

2009-01-01

281

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

SciTech Connect

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.

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

2012-01-01

282

Electrolytic Conductivity of Four Imidazolium-Based Ionic Liquids  

NASA Astrophysics Data System (ADS)

In this article, electrolytic (ionic) conductivity measurements of four ionic liquids (ILs), namely, 1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl] imide ([Cmim][NTf]), 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ([Cmim][OTf]), 1-hexyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([Cmim][NTf]), and 1-ethyl-3-methylimidazolium ethyl sulfate ([Cmim][EtSO]) (ECOENG212), were performed in a temperature range of (288.15 to 333.15) K. [Cmim][NTf] was chosen to be a reference ionic liquid for several properties, including the electrolytic conductivity by the IUPAC Project 2002-005-1-100. For that reason, the measurements performed with that ionic liquid primarily serve the purpose to validate the instrumentation and the experimental procedure used in this work. The measurements were carried out using a complex impedance method, applying a novel electronic device designed and constructed for this purpose. The complete setup includes a Schott Instruments LF 913 T, used as a four-electrode conductivity cell, and a lock-in amplifier. The cell was calibrated using standard reference KCl aqueous solutions. The measurements of the impedance of the conductivity cell were carried out along a range of frequencies from (0.2 to 30) kHz, and the results were extrapolated to infinite frequency, in order to determine the electrolytic conductivity of the liquid samples. The results obtained for the ionic liquid [Cmim][NTf] were compared to reference data, and it was estimated that the overall uncertainty of the present results is better than 2 %. All the data obtained were compared with available literature data, and were analyzed and discussed in respect to the effect of temperature, cation alkyl chain length, and anion.

Calado, Marta S.; Diogo, João C. F.; Correia da Mata, José L.; Caetano, Fernando J. P.; Visak, Zoran P.; Fareleira, João M. N. A.

2013-07-01

283

Thermoelectric Potential of Polymer-Scaffolded Ionic Liquid Membranes  

NASA Astrophysics Data System (ADS)

Organic thin films have been viewed as potential thermoelectric (TE) materials, given their ease of fabrication, flexibility, cost effectiveness, and low thermal conductivity. However, their intrinsically low electrical conductivity is a main drawback which results in a relatively lower TE figure of merit for polymer-based TE materials than for inorganic materials. In this paper, a technique to enhance the ion transport properties of polymers through the introduction of ionic liquids is presented. The polymer is in the form of a nanofiber scaffold produced using the electrospinning technique. These fibers were then soaked in different ionic liquids based on substituted imidazolium such as 1-ethyl-3-methylimidazolium chloride or 1-butyl-3-methylimidazolium bromide. This method was applied to electrospun polyacrylonitrile and a mixture of polyvinyl alcohol and chitosan polymers. The ion transport properties of the membranes have been observed to increase with increasing concentration of ionic liquid, with maximum electrical conductivity of 1.20 × 10-1 S/cm measured at room temperature. Interestingly, the maximum electrical conductivity value surpassed the value of pure ionic liquids. These results indicate that it is possible to significantly improve the electrical conductivity of a polymer membrane through a simple and cost-effective method. This may in turn boost the TE figures of merit of polymer materials, which are well known to be considerably lower than those of inorganic materials. Results in terms of the Seebeck coefficient of the membranes are also presented in this paper to provide an overall representation of the TE potential of the polymer-scaffolded ionic liquid membranes.

Datta, R. S.; Said, S. M.; Sahamir, S. R.; Karim, M. R.; Sabri, M. F. M.; Nakajo, T.; Kubouchi, M.; Hayashi, K.; Miyazaki, Y.

2014-06-01

284

Decoupling of ionic conductivity from the structural relaxation in ionic liquids  

NASA Astrophysics Data System (ADS)

In numerous technological applications, notably battery technology, the need for a highly conductive ionic material is critical. Ionic liquids are well suited for these applications, but the fundamentals of their physical properties are still not well understood. To investigate the temperature dependence of the conductivity and structural relaxation in these systems, a combination of light scattering techniques as well as dielectric spectroscopy measurements were performed on the ionic liquid [C4mim][NTf2]. Combining these measurement techniques enables us to characterize the dynamics in a time window that spans more than twelve decades. Detailed analysis of our results shows that the temperature dependence of the conductivity decouples from that of the structural relaxation. Furthermore, the structural relaxation exhibits a dynamical crossover similar to that observed in many glass forming liquids, while the conductivity exhibits no sign of the crossover. Contrary to the traditional theory, these observations suggest that the mechanism controlling ionic conductivity in this system is different from the mechanism controlling structural relaxation.

Griffin, Philip; Agapov, Alexander; Kisliuk, Alexander; Sokolov, Alexei

2011-03-01

285

Improved Ionic Conductivity of NBR\\/Epoxy Resin\\/Liclo4 Composites by Adding Ionic Liquid  

Microsoft Academic Search

Solid polymer electrolyte with high ionic conductivity was prepared by adding an ionic liquid, 1-butyl-3-methylimidazolium trifluoromethanesulfonate (BMIMOTF) to the nitrile butadiene rubber \\/epoxy resin\\/LiClO4 (NBR-EP-Li) system. The addition of BMIMOTF into NBR-EP-Li composites, with the LiClO4\\/BMIMOTF mole ratio maintained of 1\\/0.54, improved the conductivity by 6?17 times depending on the amount of LiClO4. Infrared difference spectroscopy and nuclear magnetic resonance

Qian Zhang; Ming Li; Wentan Ren; Yong Zhang

2011-01-01

286

Morphological and electromechanical characterization of ionic liquid/Nafion polymer composites  

NASA Astrophysics Data System (ADS)

Ionic liquids have shown promise as replacements for water in ionic polymer transducers. Ionic liquids are non-volatile and have a larger electrochemical stability window than water. Therefore, transducers employing ionic liquids can be operated for long periods of time in air and can be actuated with higher voltages. Furthermore, transducers based on ionic liquids do not exhibit the characteristic back relaxation that is common with water-swollen materials. However, the physics of transduction in the ionic liquid-swollen materials is not well understood. In this paper, the morphology of Nafion/ionic liquid composites is characterized using small-angle X-ray scattering (SAXS). The electromechanical transduction behavior of the composites is also investigated. For this testing, five different counterions and two ionic liquids are used. The results reveal that both the morphology and transduction performance of the composites is affected by the identity of the ionic liquid, the cation, and the swelling level of ionic liquid within the membrane. Specifically, speed of response is found to be lower for the membranes that were exchanged with the smaller lithium and potassium ions. The response speed is also found to increase with increased content of ionic liquid. Furthermore, for the two ionic liquids studied, the actuators swollen with the less viscous ionic liquid exhibited a slower response. The slower speed of response corresponds to less contrast between the ionically conductive phase and the inert phase of the polymer. This suggests that disruption of the clustered morphology in the ionic liquid-swollen membranes as compared to water-swollen membranes attenuates ion mobility within the polymer. This attenuation is attributed to swelling of the non-conductive phase by the ionic liquids.

Bennett, Matthew; Leo, Donald

2005-05-01

287

Electric double layer at the interface of ionic liquid-dielectric liquid under electric field.  

PubMed

The structure of the electric double layer (EDL) is analyzed in order to understand the electromechanical behavior of the interface of ionic liquid-dielectric liquid. The modified Poisson-Boltzmann equation proposed by Bazant et al. is solved to see the crowding and the overscreening effects that are the characteristics of an ionic liquid (Bazant, M. Z.; Storey, B. D.; Kornyshev, A. A. Double layer in ionic liquids: Overscreening versus crowding. Phys. Rev. Lett. 2011, 106, 046102.). From the simple one-dimensional (1-D) analysis, it is found that the changes of the composition and the material properties in the EDL are negligible except under some extreme conditions such as strong electric field over O(10(8)) V/m. From the electromechanical view points, an ionic liquid behaves like a pure conductor at the interface with a dielectric liquid. Based on these findings, three specific application problems are considered. In the first, a new method is suggested for measuring the interfacial tension of an ionic liquid-dielectric liquid system. The deformation of a charged ionic liquid droplet translating between two electrodes is used for this measurement. The second is for the Taylor cone problem, which includes an extreme electric field condition near the tip. The size of the critical region, where the EDL effect should be considered, is estimated by using the 1-D analysis result. Numerical computation is also performed to see the profiles of electric potential and the electric stress along the interface of the Taylor cone. Lastly, the electrowetting problem of the ionic liquid is considered. The discrepancies in the results of previous workers are interpreted by using the results of the present work. It is shown that all the results might be consistent if the leaking of the dielectric layer and/or the adsorption of ions is considered. PMID:23331068

Lee, D W; Im, D J; Kang, I S

2013-02-12

288

Importance of glassy fragility for energy applications of ionic liquids  

E-print Network

Ionic liquids (ILs) are salts that are liquid close to room temperature. Their possible applications are numerous, e.g., as solvents for green chemistry in various electrochemical devices, and even for such "exotic" purposes as spinning-liquid mirrors for lunar telescopes. Here we concentrate on their use for new advancements in energy-storage and -conversion devices: Batteries, supercapacitors or fuel cells using ILs as electrolytes could be important building blocks for the sustainable energy supply of tomorrow. Interestingly, ILs show glassy freezing and the universal, but until now only poorly understood dynamic properties of glassy matter, dominate many of their physical properties. We show that the conductivity of ILs, an essential figure of merit for any electrochemical application, depends in a systematic way not only on their glass temperature but also on the so-called fragility, characterizing the non-canonical super-Arrhenius temperature dependence of their ionic mobility.

P. Sippel; P. Lunkenheimer; S. Krohns; E. Thoms; A. Loidl

2015-02-24

289

Force microscopy of layering and friction in an ionic liquid  

NASA Astrophysics Data System (ADS)

The mechanical properties of the ionic liquid 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl) trifluorophosphate ([Py1,4][FAP]) in confinement between a SiOx and a Au(1?1?1) surface are investigated by means of atomic force microscopy (AFM) under electrochemical control. Up to 12 layers of ion pairs can be detected through force measurements while approaching the tip of the AFM to the surface. The particular shape of the force versus distance curve is explained by a model for the interaction between tip, gold surface and ionic liquid, which assumes an exponentially decaying oscillatory force originating from bulk liquid density correlations. Jumps in the tip-sample distance upon approach correspond to jumps of the compliant force sensor between branches of the oscillatory force curve. Frictional force between the laterally moving tip and the surface is detected only after partial penetration of the last double layer between tip and surface.

Hoth, Judith; Hausen, Florian; Müser, Martin H.; Bennewitz, Roland

2014-07-01

290

Computer simulations of ionic liquids at electrochemical interfaces  

E-print Network

Ionic liquids are widely used as electrolytes in electrochemical devices. In this context, many experimental and theoretical approaches have been recently developed for characterizing their interface with electrodes. In this perspective article, we review the most recent advances in the field of computer simulations (mainly molecular dynamics). A methodology for simulating electrodes at constant electrical potential is presented. Several types of electrode geometries have been investigated by many groups in order to model planar, corrugated and porous materials and we summarize the results obtained in terms of the structure of the liquids. This structure governs the quantity of charge which can be stored at the surface of the electrode for a given applied potential, which is the relevant quantity for the highly topical use of ionic liquids in supercapacitors (also known as electrochemical double-layer capacitors). A key feature, which was also shown by atomic force microscopy and surface force apparatus exper...

Merlet, Céline; Madden, Paul; Salanne, Mathieu

2013-01-01

291

Recent progress on dielectric properties of protic ionic liquids.  

PubMed

Protic ionic liquids (PILs) are key materials for a wide range of emerging technologies. In particular, these systems have long been envisioned as promising candidates for fuel cells. Therefore, in recent years special attention has been devoted to thorough studies of these compounds. Amongst others, dielectric properties of PILs at ambient and elevated pressure have become the subject of intense research. The reason for this lies in the role of broadband dielectric spectroscopy in recognizing the conductivity mechanism in protic ionic systems. In this paper, we summarize the dielectric results of various PILs reflecting recent advances in this field. PMID:25634823

Wojnarowska, Zaneta; Paluch, Marian

2015-02-25

292

Recent progress on dielectric properties of protic ionic liquids  

NASA Astrophysics Data System (ADS)

Protic ionic liquids (PILs) are key materials for a wide range of emerging technologies. In particular, these systems have long been envisioned as promising candidates for fuel cells. Therefore, in recent years special attention has been devoted to thorough studies of these compounds. Amongst others, dielectric properties of PILs at ambient and elevated pressure have become the subject of intense research. The reason for this lies in the role of broadband dielectric spectroscopy in recognizing the conductivity mechanism in protic ionic systems. In this paper, we summarize the dielectric results of various PILs reflecting recent advances in this field.

Wojnarowska, Zaneta; Paluch, Marian

2015-02-01

293

Ionic Liquids: Radiation Chemistry, Solvation Dynamics and Reactivity Patterns  

SciTech Connect

Ionic liquids (ILs) are a rapidly expanding family of condensed-phase media with important applications in energy production, nuclear fuel and waste processing, improving the efficiency and safety of industrial chemical processes, and pollution prevention. ILs are generally nonvolatile, noncombustible, highly conductive, recyclable and capable of dissolving a wide variety of materials. They are finding new uses in chemical synthesis, catalysis, separations chemistry, electrochemistry and other areas. Ionic liquids have dramatically different properties compared to conventional molecular solvents, and they provide a new and unusual environment to test our theoretical understanding of charge transfer and other reactions. We are interested in how IL properties influence physical and dynamical processes that determine the stability and lifetimes of reactive intermediates and thereby affect the courses of chemical reactions and product distributions. Successful use of ionic liquids in radiation-filled environments, where their safety advantages could be significant, requires an understanding of ionic liquid radiation chemistry. For example, characterizing the primary steps of IL radiolysis will reveal radiolytic degradation pathways and suggest ways to prevent them or mitigate their effects on the properties of the material. An understanding of ionic liquid radiation chemistry will also facilitate pulse radiolysis studies of general chemical reactivity in ILs, which will aid in the development of applications listed above. Very early in our radiolysis studies it became evident that slow solvation dynamics of the excess electron in ILs (which vary over a wide viscosity range) increases the importance of pre-solvated electron reactivity and consequently alters product distributions. Parallel studies of IL solvation phenomena using coumarin-153 dynamic Stokes shifts and polarization anisotropy decay rates are done to compare with electron solvation studies and to evaluate the influence of ILs on charge transport processes. Picosecond pulse radiolysis studies at BNL's Laser-Electron Accelerator Facility (LEAF) are used to identify reactive species in ionic liquids and measure their solvation and reaction rates. We and our collaborators (R. Engel (Queens College, CUNY) and S. Lall-Ramnarine, (Queensborough CC, CUNY)) develop and characterize new ionic liquids specifically designed for our radiolysis and solvation dynamics studies. IL solvation and rotational dynamics are measured by TCSPC and fluorescence upconversion measurements in the laboratory of E. W. Castner at Rutgers Univ. Investigations of radical species in irradiated ILs are carried out at ANL by I. Shkrob and S. Chemerisov using EPR spectroscopy. Diffusion rates are obtained by PGSE NMR in S. Greenbaum's lab at Hunter College, CUNY and S. Chung's lab at William Patterson U. Professor Mark Kobrak of CUNY Brooklyn College performs molecular dynamics simulations of solvation processes. A collaboration with M. Dietz at U. Wisc. Milwaukee is centered around the properties and radiolytic behavior of ionic liquids for nuclear separations. Collaborations with C. Reed (UC Riverside), D. Gabel (U. Bremen) and J. Davis (U. South Alabama) are aimed at characterizing the radiolytic and other properties of borated ionic liquids, which could be used to make fissile material separations processes inherently safe from criticality accidents.

Wishart,J.F.

2008-09-29

294

Can Ionic Liquids Be Used As Templating Agents For Controlled Design of Uranium-Containing Nanomaterials?  

SciTech Connect

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.

Visser, A.; Bridges, N.; Tosten, M.

2013-04-09

295

Room temperature ionic liquids as replacements for conventional solvents – A review  

Microsoft Academic Search

Room temperature ionic liquids are salts that are liquids at ambient temperature. They are excellent solvents for a broad\\u000a range of polar organic compounds and they show partial miscibility with aromatic hydrocarbons. Typical room temperature ionic\\u000a liquids have a stable liquid range of over 300 K and have a very low vapor pressure at room temperature. Ionic liquids that\\u000a are

Kenneth N. Marsh; Alex Deev; Alex C. T. Wu; Emma Tran; A. Klamt

2002-01-01

296

Reduction of Metal Oxide to Metal using Ionic Liquids  

SciTech Connect

A novel pathway for the high efficiency production of metal from metal oxide means of electrolysis in ionic liquids at low temperature was investigated. The main emphasis was to eliminate the use of carbon and high temperature application in the reduction of metal oxides to metals. The emphasis of this research was to produce metals such as Zn, and Pb that are normally produced by the application of very high temperatures. The reduction of zinc oxide to zinc and lead oxide to lead were investigated. This study involved three steps in accomplishing the final goal of reduction of metal oxide to metal using ionic liquids: 1) Dissolution of metal oxide in an ionic liquid, 2) Determination of reduction potential using cyclic voltammetry (CV) and 3) Reduction of the dissolved metal oxide. Ionic liquids provide additional advantage by offering a wide potential range for the deposition. In each and every step of the process, more than one process variable has been examined. Experimental results for electrochemical extraction of Zn from ZnO and Pb from PbO using eutectic mixtures of Urea ((NH2)2CO) and Choline chloride (HOC2H4N(CH3)3+Cl-) or (ChCl) in a molar ratio 2:1, varying voltage and temperatures were carried out. Fourier Transform Infra-Red (FTIR) spectroscopy studies of ionic liquids with and without metal oxide additions were conducted. FTIR and induction coupled plasma spectroscopy (ICPS) was used in the characterization of the metal oxide dissolved ionic liquid. Electrochemical experiments were conducted using EG&G potentiostat/galvanostat with three electrode cell systems. Cyclic voltammetry was used in the determination of reduction potentials for the deposition of metals. Chronoamperometric experiments were carried out in the potential range of -0.6V to -1.9V for lead and -1.4V to -1.9V for zinc. The deposits were characterized using XRD and SEM-EDS for phase, morphological and elemental analysis. The results showed that pure metal was deposited on the cathode. Successful extraction of metal from metal oxide dissolved in Urea/ChCl (2:1) was accomplished. The current efficiencies were relatively high in both the metal deposition processes with current efficiency greater than 86% for lead and 95% for zinc. This technology will advance the metal oxide reduction process by increasing the process efficiency and also eliminate the production of CO2 which makes this an environmentally benign technology for metal extraction.

Dr. Ramana Reddy

2012-04-12

297

SPECTROSCOPIC STUDIES OF STRUCTURE, DYNAMICS AND REACTIVITY IN IONIC LIQUIDS.  

SciTech Connect

Ionic liquids (ILs) are a rapidly expanding family of condensed-phase media with important applications in energy production, nuclear fuel and waste processing, improving the efficiency and safety of industrial chemical processes, and pollution prevention. ILs are generally nonvolatile, noncombustible, highly conductive, recyclable and capable of dissolving a wide variety of materials. They are finding new uses in chemical synthesis, catalysis, separations chemistry, electrochemistry and other areas. Ionic liquids have dramatically different properties compared to conventional molecular solvents, and they provide a new and unusual environment to test our theoretical understanding of charge transfer and other reactions. We are interested in how IL properties influence physical and dynamical processes that determine the stability and lifetimes of reactive intermediates and thereby affect the courses of chemical reactions and product distributions. Successful use of ionic liquids in radiation-filled environments, where their safety advantages could be significant, requires an understanding of ionic liquid radiation chemistry. For example, characterizing the primary steps of IL radiolysis will reveal radiolytic degradation pathways and suggest ways to prevent them or mitigate their effects on the properties of the material. An understanding of ionic liquid radiation chemistry will also facilitate pulse radiolysis studies of general chemical reactivity in ILs, which will aid in the development of applications listed above. Very early in our radiolysis studies it became evident that slow solvation dynamics of the excess electron in ILs (which vary over a wide viscosity range) increases the importance of pre-solvated electron reactivity and consequently alters product distributions. Parallel studies of IL solvation phenomena using coumarin-153 dynamic Stokes shifts and polarization anisotropy decay rates are done to compare with electron solvation studies and to evaluate the influence of ILs on charge transport processes. Picosecond pulse radiolysis studies at BNL's Laser-Electron Accelerator Facility (LEAF) [1] are used to identify reactive species in ionic liquids and measure their solvation and reaction rates. IL solvation and rotational dynamics are measured by TCSPC in the laboratory of E. W. Castner at Rutgers Univ. Investigations of radical species in irradiated ILs are carried out at ANL by I. Shkrob and S. Chemerisov using EPR spectroscopy.

WISHART,J.F.

2007-11-30

298

Destructuring ionic liquids in ionogels: enhanced fragility for solid devices.  

PubMed

Confining ionic liquids (ILs) with added lithium salt within silica host networks enhances their fragility and improves their conductivity. Overall, conductivity measurements, Raman spectroscopy of the TFSI anion and NMR spectroscopy of the lithium cation show segregative interaction of lithium ions with the SiO2 host matrix. This implies at IL/SiO2 interfaces a breakdown of aggregated regions that are found systematically in bulk ILs. Such destructuration due to the interface effect determines the fragility and thus results locally at the interface in short relaxation times, low viscosity, and good ionic conductivity. The "destructuration" of ion pairs or domains makes ILs within ionogels a competitive alternative to existing solid ionic conductors in all-solid devices, such as lithium batteries and supercapacitors. PMID:25268859

Guyomard-Lack, A; Delannoy, P-E; Dupré, N; Cerclier, C V; Humbert, B; Le Bideau, J

2014-11-21

299

Electrically switchable multi-stable cholesteric liquid crystal based on chiral ionic liquid.  

PubMed

A multi-stable and electrically switchable cholesteric liquid crystal based on chiral ionic liquid is demonstrated. The cholesteric liquid crystal can be switched among the planar texture, focal conic texture, wide-band reflected state, and fingerprint texture by applying specific electric fields. Each of these four states exists stably for several hours without any obvious change observed at room temperature. The electro-optical properties and driving scheme of the cholesteric liquid crystal are also reported. PMID:25502999

Lu, Hongbo; Xu, Wei; Song, Zhigang; Zhang, Shanna; Qiu, Longzhen; Wang, Xianghua; Zhang, Guobing; Hu, Juntao; Lv, Guoqiang

2014-12-15

300

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

SciTech Connect

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.

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

2005-01-01

301

Ionic Liquids and Solids with Paramagnetic Anions  

SciTech Connect

Four paramagnetic ionic compounds have been prepared and their magnetic, structural and thermal properties have been investigated. The four compounds are methylbutylpyrrolidinium tetrachloroferrate(III) ([Pyrr{sub 14}]{sup +}/[FeCl{sub 4}]{sup -}), methyltributylammonium tetrachloroferrate(III) ([N{sub 1444}]{sup +}/[FeCl{sub 4}]{sup -}), butylmethylimidazolium tetrachloroferrate(III) ([bmim]{sup +}/[FeCl{sub 4}]{sup -}) and tetrabutylammonium bromotrichloroferrate(III) ([N{sub 4444}]{sup +}/[FeBrCl{sub 3}]{sup -}). Temperature-dependent studies of their magnetic behaviors show that all four compounds are paramagnetic at ambient temperatures. Glass transitions are observed for only two of the four compounds, [Pyrr{sub 14}]{sup +}/[FeCl{sub 4}]{sup -} and [bmim]{sup +}/[FeCl{sub 4}]{sup -}. Crystal structures for [Pyrr{sub 14}]{sup +}/[FeCl{sub 4}]{sup -} and [N{sub 1444}]{sup +}/[FeCl{sub 4}]{sup -} are compared with the previously reported [N{sub 4444}]{sup +}/[FeBrCl{sub 3}]{sup -}.

Castner, Jr., E.W.; Wishart, J.; Krieger, B.M.; Lee, H.Y.; Emge, T.J.

2010-06-18

302

Characterization of solid electrolytes prepared from ionic glass and ionic liquid for all-solid-state lithium batteries  

Microsoft Academic Search

Glassy solid electrolytes were prepared by combining the 50Li2SO4·50Li3BO3 (mol%) ionic glass and the 1-ethyl-3-methyl-imidazolium tetrafluoroborate ([EMI]BF4) ionic liquid. High-energy ball milling was carried out for the mixture of the inorganic ionic glass and the organic ionic liquid. The ambient temperature conductivity of the glass electrolyte with 10mol% [EMI]BF4 was 10?4S cm?1, which was three orders of magnitude higher than

Akitoshi Hayashi; Hideki Morishima; Kiyoharu Tadanaga; Masahiro Tatsumisago

2011-01-01

303

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

PubMed

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

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

2014-03-01

304

Solubility and aggregation of charged surfactants in ionic liquids.  

PubMed

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

Chen, Lang G; Bermudez, Harry

2012-01-17

305

Extraordinarily Efficient Conduction in a Redox-Active Ionic Liquid  

E-print Network

Iodine added to iodide-based ionic liquids leads to extraordinarily efficient charge transport, vastly exceeding that expected for such viscous systems. Using terahertz time-domain spectroscopy, in conjunction with dc conductivity, diffusivity and viscosity measurements we unravel the conductivity pathways in 1-methyl-3-propylimidazolium iodide melts. This study presents evidence of the Grotthuss mechanism as a significant contributor to the conductivity, and provides new insights into ion pairing processes as well as the formation of polyiodides. The terahertz and transport results are reunited in a model providing a quantitative description of the conduction by physical diffusion and the Grotthuss bond-exchange process. These novel results are important for the fundamental understanding of conduction in molten salts and for applications where ionic liquids are used as charge-transporting media such as in batteries and dye-sensitized solar cells.

Verner K. Thorsmølle; Guido Rothenberger; Daniel Topgaard; Jan C. Brauer; Dai-Bin Kuang; Shaik M. Zakeeruddin; Björn Lindman; Michael Grätzel; Jacques-E. Moser

2010-11-09

306

Ionic liquid-induced synthesis of selenium nanoparticles  

SciTech Connect

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.

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

307

Ionic liquids for separation of olefin-paraffin mixtures  

DOEpatents

The invention is directed to an ionic liquid comprising (i) a cationic portion containing a complex of a silver (I) ion and one or more neutral ligands selected from organoamides, organoamines, olefins, and organonitriles, and (ii) an anionic portion having the chemical formula ##STR00001## wherein m and n are independently 0 or an integer of 1 or above, and p is 0 or 1, provided that when p is 0, the group --N--SO.sub.2--(CF.sub.2).sub.nCF.sub.3 subtended by p is replaced with an oxide atom connected to the shown sulfur atom. The invention is also directed to a method for separating an olefin from an olefin-paraffin mixture by passing the mixture through a layer of the ionic liquid described above.

Dai, Sheng; Luo, Huimin; Huang, Jing-Fang

2013-09-17

308

Carbon films produced from ionic liquid carbon precursors  

DOEpatents

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 %.

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

2013-11-05

309

IONIC LIQUIDS: RADIATION CHEMISTRY, SOLVATION DYNAMICS AND REACTIVITY PATTERNS.  

SciTech Connect

energy production, nuclear fuel and waste processing, improving the efficiency and safety of industrial chemical processes, and pollution prevention. ILs are generally nonvolatile, noncombustible, highly conductive, recyclable and capable of dissolving a wide variety of materials. They are finding new uses in chemical synthesis, catalysis, separations chemistry, electrochemistry and other areas. Ionic liquids have dramatically different properties compared to conventional molecular solvents, and they provide a new and unusual environment to test our theoretical understanding of charge transfer and other reactions. We are interested in how IL properties influence physical and dynamical processes that determine the stability and lifetimes of reactive intermediates and thereby affect the courses of chemical reactions and product distributions. Successful use of ionic liquids in radiation-filled environments, where their safety advantages could be significant, requires an understanding of ionic liquid radiation chemistry. For example, characterizing the primary steps of IL radiolysis will reveal radiolytic degradation pathways and suggest ways to prevent them or mitigate their effects on the properties of the material. An understanding of ionic liquid radiation chemistry will also facilitate pulse radiolysis studies of general chemical reactivity in ILs, which will aid in the development of applications listed above. Very early in our radiolysis studies it became evident that slow solvation dynamics of the excess electron in ILs (which vary over a wide viscosity range) increases the importance of pre-solvated electron reactivity and consequently alters product distributions. Parallel studies of IL solvation phenomena using coumarin-153 dynamic Stokes shifts and polarization anisotropy decay rates are done to compare with electron solvation studies and to evaluate the influence of ILs on charge transport processes. Methods. Picosecond pulse radiolysis studies at BNL's Laser-Electron Accelerator Facility (LEAF) are used to identify reactive species in ionic liquids and measure their solvation and reaction rates. We and our collaborators (R. Engel (Queens College, CUNY) and S. Lall-Ramnarine, (Queensborough CC, CUNY)) develop and characterize new ionic liquids specifically designed for our radiolysis and solvation dynamics studies. IL solvation and rotational dynamics are measured by TCSPC and fluorescence upconversion measurements in the laboratory of E. W. Castner at Rutgers Univ. Investigations of radical species in irradiated ILs are carried out at ANL by I. Shkrob and S. Chemerisov using EPR spectroscopy. Diffusion rates are obtained by PGSE NMR in S. Greenbaum's lab at Hunter College, CUNY and S. Chung's lab at William Patterson U. Professor Mark Kobrak of CUNY Brooklyn College performs molecular dynamics simulations of solvation processes. A collaboration with M. Dietz and coworkers at ANL is centered around the properties and radiolytic behavior of ionic liquids for nuclear separations. Collaborations with C. Reed (UC Riverside), D. Gabel (U. Bremen) and J. Davis (U. South Alabama) are aimed at characterizing the radiolytic and other properties of borated ionic liquids, which could be used to make fissile material separations processes inherently safe from criticality accidents.

WISHART,J.F.

2007-10-01

310

Distinctive Nanoscale Organization of Dicationic versus Monocationic Ionic Liquids  

SciTech Connect

The distinctive structural organization of dicationic ionic liquids (DILs) with varying alkyl linkage chain lengths is systematically investigated using classical molecular dynamics (MD) simulations. In comparison with their counterparts, monocationic ionic liquids (MILs) with free alkyl chain, the DILs with short linkage chains exhibit almost identical structural features regardless of anion types, whereas the long-chain DILs display a relatively insignificant prepeak and low heterogeneity order parameter (HOP), which is accompanied by the less evident structural heterogeneity. Moreover, the predominant role of anion type in the structure of DILs was verified, similar to what is observed in MILs. Finally, the different nanoscale organizations in DILs and MILs are rationalized by the relatively unfavorable straight and folded chain models proposed for the nanoaggregates in DILs and the favorable micelle-like arrangement for those in MILs.

Li, Song [Vanderbilt University, Nashville] [Vanderbilt University, Nashville; Feng, Guang [ORNL] [ORNL; Banuelos, Jose Leo [ORNL] [ORNL; Rother, Gernot [ORNL] [ORNL; Fulvio, Pasquale F [ORNL] [ORNL; Dai, Sheng [ORNL] [ORNL; Cummings, Peter T [ORNL] [ORNL

2013-01-01

311

Ionic liquids for separation of olefin-paraffin mixtures  

DOEpatents

The invention is directed to an ionic liquid comprising (i) a cationic portion containing a complex of a silver (I) ion and one or more neutral ligands selected from organoamides, organoamines, olefins, and organonitriles, and (ii) an anionic portion having the chemical formula ##STR00001## wherein m and n are independently 0 or an integer of 1 or above, and p is 0 or 1, provided that when p is 0, the group --N--SO.sub.2--(CF.sub.2).sub.nCF.sub.3 subtended by p is replaced with an oxide atom connected to the shown sulfur atom. The invention is also directed to a method for separating an olefin from an olefin-paraffin mixture by passing the mixture through a layer of the ionic liquid described above.

Dai, Sheng; Luo, Huimin; Huang, Jing-Fang

2014-07-15

312

Multiple zeolite structures from one ionic liquid template.  

PubMed

This study reports the use of 1-butyl-3-methyl imidazolium methanesulfonate ionic liquid as a template in the synthesis of zeolites. It is found that the silicon source determines the formation of beta (BEA), mordenite framework inverted (MFI), or analcime (ANA) zeolites. Depending on this source, different preorganized complexes are obtained that drive the formation of the different zeolite structures. In the presence of ethanol, the ionic liquid form preorganized complexes that drive the formation of MFI. In its absence, BEA is obtained. Whereas, the large amount of sodium present when using sodium metasilicate leads to ANA formation. A molecular simulation study of the relative stability of the template-framework system and location of the template provides further insight into the mechanism of synthesis. PMID:23255393

Martínez Blanes, José María; Szyja, Bart?omiej M; Romero-Sarria, Francisca; Centeno, Miguel Ángel; Hensen, Emiel J M; Odriozola, José Antonio; Ivanova, Svetlana

2013-02-01

313

Revisiting ether-derivatized imidazolium-based ionic liquids.  

PubMed

A series of ether-derivatized imidazolium halides have been prepared and characterized. Contrary to literature reports, they are all crystalline solids and have melting points well above room temperature (50-100 degrees C). Single crystals of the imidazolium salts, obtained in situ by slow cooling from their molten state to room temperature, were analyzed by X-ray crystallography, revealing various anion-cation interactions in the solid state. Exchange of the halides with [Tf(2)N]- yielded room temperature ionic liquids with viscosities that are comparable to related 1-alkyl-3-methylimidazolium ionic liquids. Density functional theory combined with IR spectroscopy has been used to analyze the role of functionalization of the imidazolium side chain on the formation of the molecular and supramolecular structure of the compounds and its possible impact on their physical properties. PMID:17676796

Fei, Zhaofu; Ang, Wee Han; Zhao, Dongbin; Scopelliti, Rosario; Zvereva, Elena E; Katsyuba, Sergey A; Dyson, Paul J

2007-08-30

314

Protic pharmaceutical ionic liquids and solids: aspects of protonics.  

PubMed

A series of new protic compounds based on active pharmaceutical ingredients have been synthesised and characterised. Some of the salts synthesised produced ionic liquids, while others that were associated with rigid molecular structures tended to produce high melting points. The "protonic" behaviour of these compounds was found to be a major determinant of their properties. Indicator studies, FTIR-ATR and transport properties (Walden plot) were used to probe the extent of proton transfer and ion association in these ionic liquids. While proton transfer was shown to have taken place in all cases, the Walden plot indicated strong ion association in the primary amine based examples due to hydrogen bonding. This was further explored via crystal structures of related compounds, which showed that extended hydrogen bonded clusters tend to form in these salts. These clusters may dictate membrane transport properties of these compounds in vivo. PMID:22455028

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

2012-01-01

315

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

PubMed

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

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

2015-02-01

316

American Institute of Aeronautics and Astronautics Ferroelectrohydrodynamics of ionic liquid ferrofluid  

E-print Network

American Institute of Aeronautics and Astronautics 1 Ferroelectrohydrodynamics of ionic liquid, the ionic liquid ferrofluid described by Meyer and King is the first liquid to simultaneously respond superparamagnetic liquid. 6,7 When this fluid is subjected to simultaneous magnetic and electric fields a self

King, Lyon B.

317

Ionic liquid based sodium ion conducting gel polymer electrolytes  

Microsoft Academic Search

A novel thermally and electrochemically stable sodium ion conducting gel polymer electrolyte has been reported, which comprises a solution of NaCF3SO3 (sodium triflate or NaTf) in a room temperature ionic liquid 1-ethyl 3-methyl imidazolium trifluoro-methane sulfonate (EMI-triflate or EMITf) immobilized in poly (vinylidine fluoride-co-hexafluoropropylene) (PVdF-HFP). Different structural, thermal, electrical and electrochemical studies demonstrate promising characteristics of the polymer films, suitable

Deepak Kumar; S. A. Hashmi

2010-01-01

318

Application of room temperature ionic liquids to Li batteries  

Microsoft Academic Search

Novel electrolyte materials, room temperature ionic liquids (RTILs) were applied to the Li battery system and their characteristics in Li-metal batteries are discussed, partly reviewing authors work in the past. Quaternary ammonium (QA) cation-imide RTIL was focused on because of the excellent stability in cathodic environment of Li. Li\\/LiCoO2 cell performance and Li cycling efficiency using the selected QA-imide RTIL

Hikari Sakaebe; Hajime Matsumoto; Kuniaki Tatsumi

2007-01-01

319

Mixed ionic liquid as electrolyte for lithium batteries  

Microsoft Academic Search

Ionic liquids like 1-butyl-3-methylimidazolium tetrafluoroborate (IMIBF4) or hexafluorophosphate (IMIPF6) and 1-butyl-4-methylpyridinium tetrafluoroborate (PyBF4) were mixed with organic solvents such as butyrolactone (BL) and acetonitrile (ACN). A lithium salt (LiBF4 or LiPF6) was added to these mixtures for possible application in the field of energy storage (batteries or supercapacitors). Viscosities, conductivities and electrochemical windows at a Pt electrode of these electrolytes

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

2005-01-01

320

1Octanol\\/Water Partition Coefficient of Ionic Liquids  

Microsoft Academic Search

Room temperature ionic liquids are nonvolatile, they can only disperse into the aquatic environment. 1-octanol-water partition coefficient is a measure of the bioconcentration tendency of a chemical in a hydrologic cycle. In this work, 1-octanol-water partition coefficient of 1-ethyl-3-methylimidazolium hexafluoro- phosphate ((emim)(PF6)) and 1-butyl-3-methylimidazolium hexafluorophosphate ((bmim)(PF6)) at 303 K were measured using ultraviolet spectrometer and Karl-Fischer analysis. The 1-octanol\\/water partition

Cheng-Huang Choua; Fu-Shan Perng; David Shan; Hill Wong; Wen Cheng Su

321

Task Specific Ionic Liquids and Task Specific Onium Salts  

Microsoft Academic Search

\\u000a Task specific ionic liquids (TSILs), or more generally task specific onium salts (TSOSs), can be defined as an association\\u000a of a cation and anion, one at least being organic, to which has covalently been attached through a linker a function that\\u000a confers the assembly a specific task. After presentation of the general concept of TSILs and TSOSs, the different methods

Mathieu Pucheault; Michel Vaultier

2010-01-01

322

Electropolymerization of ionic liquid substituted polyphenylene as supercapacitors materials  

Microsoft Academic Search

A new type of polyphenylene, ionic liquid (IL) 1,3-methylimidazolium hexafluorophosphate substituted, has been prepared by electrodeposition on Au electrode surface via pulse galvanostatic method in 1-butyl-3-methylimidazolium hexafluorophosphate solution. The obtained polymer film had a spherulitic morphology with smallest grains of around 500nm. Infrared spectrometry revealed that polyphenylene was deposited to a certain extent. The capacitive behavior of the IL substituted

Deliang He; Yanni Guo; Zhou Zhou; Sanbao Xia; Xin Xie; Ronghua Yang

2009-01-01

323

MINOR ACTINIDE SEPARATIONS USING ION EXCHANGERS OR IONIC LIQUIDS  

SciTech Connect

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.

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

2011-09-20

324

Correlation between thermostability and stability of glycosidases in ionic liquid  

Microsoft Academic Search

The activity and stability of a ?-glycosidase (Thermus thermophilus) and two ?-galactosidases (Thermotoga maritima and Bacillus stearothermophilus) were studied in different hydrophilic ionic liquid (IL)\\/water ratios. For the ILs used, the glycosidases showed the best\\u000a stability and activity in 1,3-dimethylimidazolium methyl sulfate [MMIM][MeSO4] and 1,2,3-trimethylimidazolium methyl sulfate [TMIM][MeSO4]. A close correlation was observed between the thermostability of the enzymes and

Salim Ferdjani; Marina Ionita; Bimalendu Roy; Michel Dion; Zeineddine Djeghaba; Claude Rabiller; Charles Tellier

2011-01-01

325

Instructions for use Dielectric spectroscopy study on ionic liquid microemulsion composed of  

E-print Network

ionic species that are available in huge variety.1 Therefore people can easily prepare task-specificInstructions for use #12;Dielectric spectroscopy study on ionic liquid microemulsion composed://jcp.aip.org/about/rights_and_permissions #12;THE JOURNAL OF CHEMICAL PHYSICS 136, 244505 (2012) Dielectric spectroscopy study on ionic liquid

Tsunogai, Urumu

326

American Institute of Aeronautics and Astronautics Species measurements in the beam of an ionic liquid  

E-print Network

AFB Nirmesh Jain** and Brian S. Hawkett The University of Sydney, NSW 2006, Australia An ionic liquid mass spectra were compared to a pure ionic liquid needle source quadrupole spectraAmerican Institute of Aeronautics and Astronautics 1 Species measurements in the beam of an ionic

King, Lyon B.

327

Assessing the factors responsible for ionic liquid toxicity to aquatic organisms via quantitative structureproperty relationship modeling  

E-print Network

Ionic liquids (ILs), defined as pure ionic compounds with melting points below 100 uC, have drawnAssessing the factors responsible for ionic liquid toxicity to aquatic organisms via quantitative structure­property relationship modeling David J. Couling,a Randall J. Bernot,b Kathryn M. Docherty,b Ja

Bernot, Randall

328

The solvation structures of cellulose microfibrils in ionic liquids  

SciTech Connect

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.

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

2011-01-01

329

A roadmap to uranium ionic liquids: anti-crystal engineering.  

PubMed

In the search for uranium-based ionic liquids, tris(N,N-dialkyldithiocarbamato)uranylates have been synthesized as salts of the 1-butyl-3-methylimidazolium (C4mim) cation. As dithiocarbamate ligands binding to the UO2(2+) unit, tetra-, penta-, hexa-, and heptamethylenedithiocarbamates, N,N-diethyldithiocarbamate, N-methyl-N-propyldithiocarbamate, N-ethyl-N-propyldithiocarbamate, and N-methyl-N-butyldithiocarbamate have been explored. X-ray single-crystal diffraction allowed unambiguous structural characterization of all compounds except N-methyl-N-butyldithiocarbamate, which is obtained as a glassy material only. In addition, powder X-ray diffraction as well as vibrational and UV/Vis spectroscopy, supported by computational methods, were used to characterize the products. Differential scanning calorimetry was employed to investigate the phase-transition behavior depending on the N,N-dialkyldithiocarbamato ligand with the aim to establish structure-property relationships regarding the ionic liquid formation capability. Compounds with the least symmetric N,N-dialkyldithiocarbamato ligand and hence the least symmetric anions, tris(N-methyl-N-propyldithiocarbamato)uranylate, tris(N-ethyl-N-propyldithiocarbamato)uranylate, and tris(N-methyl-N-butyldithiocarbamato)uranylate, lead to the formation of (room-temperature) ionic liquids, which confirms that low-symmetry ions are indeed suitable to suppress crystallization. These materials combine low melting points, stable complex formation, and hydrophobicity and are therefore excellent candidates for nuclear fuel purification and recovery. PMID:24737451

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

2014-05-19

330

Understanding the impact of ionic liquid pretreatment on eucalyptus  

SciTech Connect

The development of cost-competitive biofuels necessitates the realization of advanced biomass pretreatment technologies. Ionic liquids provide a basis for one of the most promising pretreatment technologies and are known to allow effective processing of cellulose and some biomass species. Here, we demonstrate that the ionic liquid 1-ethyl-3-methyl imidazolium acetate, [C2mim][OAc], induces structural changes at the molecular level in the cell wall of Eucalyptus globulus. Deacetylation of xylan, acetylation of the lignin units, selective removal of guaiacyl units (increasing the syringyl:guaiacyl ratio) and decreased {beta}-ether content were the most prominent changes observed. Scanning electron microscopy images of the plant cell wall sections reveal extensive swelling during [C2mim][OAc] pretreatment. X-ray diffraction measurements indicate a change in cellulose crystal structure from cellulose I to cellulose II after [C2mim][OAc] pretreatment. Enzymatic saccharification of the pretreated material produced increased sugar yields and improved hydrolysis kinetics after [C2mim][OAc] pretreatment. These results provide new insight into the mechanism of ionic liquid pretreatment and reaffirm that this approach may be promising for the production of cellulosic biofuels from woody biomass.

Centikol, Ozgul [Joint Bioenergy Institute; Dibble, Dean [Joint Bioenergy Institute; Cheng, Gang [Joint Bioenergy Institute; Kent, Michael S [ORNL; Knierim, Manfred [Joint Bioenergy Institute; Melnichenko, Yuri B [ORNL

2010-01-01

331

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

NASA Astrophysics Data System (ADS)

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.

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

2009-03-01

332

Dynamic effects in thin liquid films containing ionic surfactants  

NASA Astrophysics Data System (ADS)

This paper is dedicated to studying dynamic effects in thin liquid films (TLF) containing ionic surfactants. The standard theory of TLF drainage has been developed without considering the electrical double layer (EDL) in the hydrodynamic equations, although EDL always exists. In addition, it has been found that this theory very well describes the drainage of TLF containing non-ionic surfactants in the presence of electrolytes. The inclusion of EDL into the hydrodynamics of TLF complicates the theory, producing additional dynamic effects during film drainage. For example, a gradient of electrostatic disjoining pressure across the film arises, thus causing non-uniform electrostatic repulsion between the film surfaces. This paper analyzes the hydrodynamics of TLF with EDL. A new equation of drainage was derived. This equation accounts for the non-uniform distribution of surface charges during the films drainage, which is coupled with non-uniform electrostatic repulsion between the film surfaces and results in faster film drainage. The theory was tested with drainage experiments on TLF with ionic surfactants. Foam films containing sodium dodecyl sulfate (SDS) in the presence and in the absence of added electrolyte were studied and the experimental data compared to the theoretical predictions. The experimental results, however, disagree with the theory. For example, the kinetic equation predicted faster film drainage for foam films at low ionic strength; at high ionic strength the theory tends to wReynolds drainagew. Inversely, the experiment exhibited slower drainage than predicted by the Reynolds equation in both cases of low and high ionic strengths. Numerical simulations yielded V/VRe<1. In addition, cases of wpositivew and wnegativew velocity of film surfaces were shown. Despite the sign of the velocity the dependence V/VRe<1 remained. The analysis showed similarity between the experimental data and the prediction of the Manev-Tsekov-Radoev (MTR) drainage model at R

Karakashev, S. I.; Tsekov, R.; Ivanova, D. S.

2010-03-01

333

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

PubMed Central

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

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

2012-01-01

334

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

PubMed

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 [C(4)mim][PF(6)] ionic liquid films and Aquivion membranes with 40 wt% [C(2)mim][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) = ?(D)d/(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 d(2) dependence. However, at high voltages (> 0.5 V) in which significant device responses occur, the charging process does not show d(2) dependence so that ?(diff) = d(2)/(4D), corresponding to the ion diffusion from the bulk region, was not observed. PMID:22423148

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

2012-02-10

335

Imidazolium-based poly(ionic liquid)s as new alternatives for CO2 capture.  

PubMed

Solid imidazolium-based poly(ionic liquid)s with variable molecular weights that contain the poly[2-(1-butylimidazolium-3-yl)ethyl methacrylate] (BIEMA) cation and different counter anions were evaluated in terms of CO2 capture and compared with classical ionic liquids with similar counter anions. In addition to poly(ionic liquid)s with often-applied ions such as BF4 (-) , PF6 (-) , NTf2 (-) , trifluoromethanesulfonate (OTf(-) ) and Br(-) , for the first time [BIEMA][acetate] was synthesised, which revealed a remarkably high CO2 sorption performance that exceeded the poly(ionic liquid)s studied previously on average by a factor of four (12.46 mg gPIL (-1) ). This study provides an understanding of the factors that affect CO2 sorption and a comparison of the CO2 capture efficiency with the frequently used sorbents. Moreover, all the studied sorbents were reusable if regenerated under carefully selected conditions and can be considered as suitable candidates for CO2 sorption. PMID:23881741

Privalova, Elena I; Karjalainen, Erno; Nurmi, Mari; Mäki-Arvela, Päivi; Eränen, Kari; Tenhu, Heikki; Murzin, Dmitry Yu; Mikkola, Jyri-Pekka

2013-08-01

336

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

Microsoft Academic Search

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 Sr2+ from aqueous solutions has been evaluated. The extraction properties of these TSILs can be influenced by the structures of the covalently

Huimin Luo; Sheng Dai; Peter V. Bonnesen; A BUCHANANIII

2006-01-01

337

Phosphonium chloromercurate room temperature ionic liquids of variable composition.  

PubMed

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

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

2013-12-16

338

The use of ionic liquid ion sources (ILIS) in FIB applications  

E-print Network

A new monoenergetic, high-brightness ion source can be constructed using an arrangement similar to liquid metal ion sources (LMIS) by substituting the liquid metal with an ionic liquid, or room temperature molten salt. Ion ...

Zorzos, Anthony Nicholas

2009-01-01

339

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

NASA Astrophysics Data System (ADS)

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 1H NMR and 13C 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.

Lethesh, Kallidanthiyil Chellappan; Wilfred, Cecilia Devi; Taha, M. F.; Thanabalan, M.

2014-10-01

340

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

PubMed

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

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

2014-09-15

341

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

SciTech Connect

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.

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

342

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

PubMed

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

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

2013-01-01

343

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

PubMed Central

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

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

2013-01-01

344

Applications of Ionic Liquid Technologies to Nuclear Separations  

SciTech Connect

Room temperature Ionic Liquids (ILs), organic salts that are liquid at, or close to room temperature have great potential application for uses in liquid-liquid separations processes. As a class of liquids, ILs typically have wide liquid ranges, are non-volatile, and have solvent characteristics (hydro- and lipophilicity, hydrogen-bond donor and acceptor ability etc) that can be controlled and modified by suitable changes to either the cation or anionic components of the IL. We have begun the exploration of actinide separations using a variety of technologies based upon the use of ILs including, liquid/liquid extraction using traditional extractants; incorporating an extractant functionality into an IL; immobilizing IL extractant phases on solid supports; and utilization of the solubilizing power of ILs to prepare cellulose-based materials for f-element separations. ILs can thus be considered as a new class of materials for nuclear separations, distinct from molecular solvents a nd from high temperature molten salts, with adjustable solvent characteristics, unique properties, and the potential for enhancing the principles of ''green'' chemistry in various chemical processes.

Rogers, Robin D.; Holbrey, John D.; Spear, Scott K.; Gutowski, Keith E.; Bridges, Nicholas J.; Cocalia, Violina A.; Swatloski, Richard P.

2003-09-10

345

Application of Ionic Liquids in High Performance Reversed-Phase Chromatography  

PubMed Central

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

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

2009-01-01

346

Polysiloxane ionic liquids as good solvents for ?-cyclodextrin-polydimethylsiloxane polyrotaxane structures  

PubMed Central

Summary An ionic liquid based on polydimethylsiloxane with imidazolium salt brushes was synthesized as a good solvent for ?-cyclodextrin-polydimethylsiloxane rotaxane. As expected the PDMS-Im/Br ionic liquid had a liquid-like non-Newtonian behavior with rheological parameters dependent on frequency and temperature. The addition of rotaxane to the ionic liquid strengthened the non-Newtonian character of the sample and a type of stable liquid-like network was formed due to the contribution of weak ionic interactions. The structure is stable in the 20 to 80 °C domain as proved by the oscillatory and rotational rheological tests. PMID:23209493

Marangoci, Narcisa; Ardeleanu, Rodinel; Ursu, Laura; Ibanescu, Constanta; Danu, Maricel; Simionescu, Bogdan C

2012-01-01

347

Dynamic electrowetting and dewetting of ionic liquids at a hydrophobic solid-liquid interface.  

PubMed

The dynamic electrowetting and dewetting of ionic liquids are investigated with high-speed video microscopy. Five imidazolium-based ionic liquids ([BMIM]BF(4), [BMIM]PF(6), [BMIM]NTf(2), [HMIM]NTf(2), and [OMIM]BF(4)) are used as probe liquids. Droplets of ionic liquids are first spread on an insulated electrode by applying an external voltage (electrowetting) and then allowed to retract (dewetting) when the voltage is switched off. The base area of the droplet varies exponentially during both the electrowetting and retraction processes. The characteristic time increases with the viscosity of the ionic liquid. The electrowetting and retraction kinetics (dynamic contact angle vs contact line speed) can be described by the hydrodynamic or the molecular-kinetic model. Energy dissipation occurs by viscous and molecular routes with a larger proportion of energy dissipated at the three-phase contact line when the liquid meniscus retracts from the solid surface. The outcomes from this research have implications for the design and control of electro-optical imaging systems, microfluidics, and fuel cells. PMID:23362860

Li, Hua; Paneru, Mani; Sedev, Rossen; Ralston, John

2013-02-26

348

Graphene/Ionic Liquid Composite Films and Ion Exchange  

NASA Astrophysics Data System (ADS)

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.

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

2014-06-01

349

Ion shape effect on dynamics of ionic liquids  

NASA Astrophysics Data System (ADS)

Ionic liquids (ILs) are a group of salts composing of an organic cation and organic or inorganic anion with melting points below 100 ^oC and have many suitable properties, such as negligible vapor pressure, low flammability, high ionic conductivity and high thermal stability for various applications. Moreover, a great number of ILs with a variety of physical and chemical properties can be synthesized from a combination of different cations (most differently substituted imidazolium, pyridinium, and quaternary ammonium or phosphonium ions) and anions. One can judiciously select from a multitude of ILs to suit a specific application, where the concept of designer solvent comes from. To expedite the development process of target ILs, it is crucial to understand the relationship between ion shape and dynamics of ILs. We studied a wide range of ILs with different ion shape pairings and found the planar-planar paired ILs have a better dynamics as a whole.

Liu, Hongjun; Maginn, Edward

2012-02-01

350

Graphene/Ionic Liquid Composite Films and Ion Exchange  

PubMed Central

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

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

2014-01-01

351

Mechanism of graphene formation by graphite electro-exfoliation in ionic liquids-water mixtures  

NASA Astrophysics Data System (ADS)

Graphene was produced from graphite electrode by exfoliation in ionic liquid. The influences of process parameters such as ionic liquid concentration, electrolysis potential and the type of anions in the ionic liquid on the production of graphene were studied, and a new mechanism is proposed. The results show that the increase of ionic liquid concentration is beneficial for the formation of graphene, and it is easier to produce graphene by increasing the applied voltage. Ionic liquids anions have great effect on the production of graphene. Both graphite anode and graphite cathode can be modified to graphene during electrolysis. Gases formed inside of the electrode play an important role for the production of graphene, while ionic liquids serve to accelerate the switching rate of graphite to graphene.

Xu, Junli; Shi, Zhongning; Zhang, Xia; Haarberg, Geir Martin

2014-12-01

352

Ionic liquid batteries: Chemistry to replace alkaline\\/acid energy storage devices  

Microsoft Academic Search

Rather than depend on highly acidic or basic electrolytes, ionic liquids are used to create new types of solid state cells which mimic standard alkaline cells, but without the need for caustic electrolytes. Presented here is a non-aqueous approach to primary and secondary power sources, where the pure ionic liquid not only acts as the electrolyte\\/separator in both liquid and

Thomas E. Sutto; Teresa T. Duncan; Tiffany C. Wong; Karen McGrady

2011-01-01

353

Development of a Universal Method Based on Ionic Liquids for Determination of  

E-print Network

Chapter 4 Development of a Universal Method Based on Ionic Liquids for Determination as a solvent and also as a chiral selector. Ionic liquids (ILs) are a group of organic salts that are liquid, substantial advances have been made, and it has been estimated that the number of novel and task-specific ILs

Reid, Scott A.

354

Gas Hydrate Equilibrium Measurements for Multi-Component Gas Mixtures and Effect of Ionic Liquid Inhibitors  

E-print Network

sample were collected and compared to HydraFLASH® predictions. Different percentages of 2-hydroxy-N,N,N-trimethylethanaminium chloride, also known as choline chloride ionic liquid, were used as hydrate inhibitor for the same gas mixture. The ionic liquid’s...

Othman, Enas Azhar

2014-04-07

355

Chiral Ionic Liquid that Functions as Both Solvent and Chiral Selector for the Determination of  

E-print Network

Chiral Ionic Liquid that Functions as Both Solvent and Chiral Selector for the Determination synthesized both enantiomers of a novel chiral ionic liquid, (R)- and (S)-[(3-chloro-2-hy- droxypropyl), is liquid at room temperature (glass transition temperature of -58.4 °C), and exhibits strong enantiomeric

Reid, Scott A.

356

Photoresponsive ionic liquid crystals based on azobenzene guanidinium salts.  

PubMed

The use of non-ionic LC phases as anisotropic matrices for E/Z-isomerization of azo-guest molecules is often restricted due to limited solubilities and demixing effects. In this study we therefore employed an ionic liquid crystal (ILC) matrix to follow the photo-induced E/Z-isomerization of ionic mesogenic azobenzene guanidinium guests. The latter were prepared from 4-hydroxy-4'-(octyloxy)azobenzene, which was first treated with N-(bromoalkyl)phthalimides to introduce the spacer with varying chain length. Removal of phthalimide and final reaction with a formamidinium salt linked the ionic head group to the photoisomerizable azobenzene unit. Investigation of the mesomorphic behaviour revealed for all azobenzene ILCs smectic A mesophases with high translational order parameters and partial bilayers, as could be stated by layer spacing d. Similar packing behaviour was found for the solid state by X-ray crystal structure analysis. E/Z-isomerization of azobenzene ILCs which were completely miscible with the ionic LC phase of C12MIM-Br as anisotropic host was induced by irradiation with UV light and the reisomerization observed by time-resolved UV-Vis spectroscopy. For comparison, water was used as isotropic host. Z/E-reisomerization activation energies exhibited similar values of 97-100 kJ mol(-1) irrespective of spacer lengths and the type of host. The results demonstrate that a proper match of steric requirements of host and guest as well as layer spacings are needed for a decreased activation energy. PMID:25537850

Wuckert, Eugen; Harjung, Marc D; Kapernaum, Nadia; Mueller, Carsten; Frey, Wolfgang; Baro, Angelika; Giesselmann, Frank; Laschat, Sabine

2015-04-01

357

Low-melting mixtures based on choline ionic liquids.  

PubMed

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

Rengstl, Doris; Fischer, Veronika; Kunz, Werner

2014-11-01

358

Ionic liquid foam floatation coupled with ionic liquid dispersive liquid-liquid microextraction for the separation and determination of estrogens in water samples by high-performance liquid chromatography with fluorescence detection.  

PubMed

An ionic liquid foam floatation coupled with ionic liquid dispersive liquid-liquid microextraction method was proposed for the extraction and concentration of 17-?-estradiol, 17-?-estradiol-benzoate, and quinestrol in environmental water samples by high-performance liquid chromatography with fluorescence detection. 1-Hexyl-3-methylimidazolium tetrafluoroborate was applied as foaming agent in the foam flotation process and dispersive solvent in microextraction. The introduction of the ion-pairing and salting-out agent NH4 PF6 was beneficial to the improvement of recoveries for the hydrophobic ionic liquid phase and analytes. Parameters of the proposed method including concentration of 1-hexyl-3-methylimidazolium tetrafluoroborate, flow rate of carrier gas, floatation time, types and concentration of ionic liquids, salt concentration in samples, extraction time, and centrifugation time were evaluated. The recoveries were between 98 and 105% with relative standard deviations lower than 7% for lake water and well water samples. The isolation of the target compounds from the water was found to be efficient, and the enrichment factors ranged from 4445 to 4632. This developing method is free of volatile organic solvents compared with regular extraction. Based on the unique properties of ionic liquids, the application of foam floatation, and dispersive liquid-liquid microextraction was widened. PMID:25146581

Zhang, Rui; Wang, Chuanliu; Yue, Qiaohong; Zhou, Tiecheng; Li, Na; Zhang, Hanqi; Hao, Xiaoke

2014-11-01

359

High rate performance of a lithium polymer battery using a novel ionic liquid polymer composite  

Microsoft Academic Search

We present a new design of a lithium gel-polymer battery, fabricated with a (LILP) composite consisting of a lithium salt dissolved in an ionic liquid (binary Li-IL) and an ultra high molecular weight ionic liquid polymer (ILP). This polymer, with a Mw of over a million, was prepared by the bulk radical polymerization of a novel ionic liquid monomer, N,N-diethyl-N-(2-methacryloylethyl)-N-methylammonium

Takaya Sato; Shoko Marukane; Takuya Narutomi; Tadayoshi Akao

2007-01-01

360

Polymer electrolyte for lithium batteries based on photochemically crosslinked poly(ethylene oxide) and ionic liquid  

Microsoft Academic Search

Polymer\\/ionic liquid composites were investigated as solvent-free electrolytes for lithium batteries. Ternary electrolytes based upon poly(ethylene oxide), an ionic liquid and a conducting salt were UV crosslinked with benzophenone as the photoinitiator. Crosslinking leads to an increase in mechanical stability of the PEO composites. This straight-forward process provides a way to increase the content of ionic liquid and thus to

Barbara Rupp; Martin Schmuck; Andrea Balducci; Martin Winter; Wolfgang Kern

2008-01-01

361

An ionic liquid-mediated expeditious route to the syntheses of diaryl sulfoxides  

Microsoft Academic Search

A fast and efficient protocol is proposed for the synthesis of diaryl sulfoxides in the ionic liquid 1-butyl-3-methylimidazolium chloroaluminate, [bmim]Cl·AlCl3, N=0.67, by employing arenes and thionyl chloride. The ionic liquid plays a dual role of Lewis acid catalyst and solvent, under ambient conditions, offering good yields of the product. The influence of the Lewis acidity of the ionic liquid on

Swapnil S. Mohile; Mahesh K. Potdar; Manikrao M. Salunkhe

2003-01-01

362

Deep Desulfurization of Diesel Fuel by Extraction with Task-Specific Ionic Liquids  

Microsoft Academic Search

Extraction of S-compounds from diesel oil by task-specific ionic liquids has been investigated. The influences of different ionic liquids, extraction time, extraction temperature, different S-compounds, the amount, and the recycling of ionic liquid were studied. This process is capable of removing up to 56% of dibenzothiophene in model diesel oil under optimum extraction conditions. At the same time, this process

D. Liu; J. Gui; L. Song; X. Zhang; Z. Sun

2008-01-01

363

Research Progress in Absorption of CO2 Using Task-Specific Ionic Liquids  

Microsoft Academic Search

By contrast with the conventional ionic liquids, owing to the high absorption capacity of CO2, the task-specific ionic liquids are very hopeful to replace the traditional alkanolamine which is volatile, corrosive strongly and easy oxygenated at high temperature.However,when their absorp tion capacity can be more greatly enhanced by amine functionalization than the conventional ionic liquids,the viscosity will also be increased.Neverthless,

Jun Zhang; Guang-Fei Qu; Ping Ning; Yu-Huan Liu; Yu-Kun Shi; Hui Feng

2011-01-01

364

Task-specific ionic liquid-assisted extraction and separation of astaxanthin from shrimp waste  

Microsoft Academic Search

Astaxanthin, as an outstanding antioxidant reagent, was successfully extracted from shrimp waste by the ionic liquids based ultrasonic-assisted extraction. Seven kinds of imidazolium ionic liquids with different cations and anions were investigated in this work and one task-specific ionic liquid in ethanol with 0.50molL?1 was selected as the solvent. At the optimized ultrasonic extraction conditions, the extraction amount of astaxanthin

Wentao Bi; Minglei Tian; Jun Zhou; Kyung Ho Row

2010-01-01

365

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

SciTech Connect

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.

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

366

D,L???Tocopherol Synthesis Catalyzed by the Brønsted Acidic Ionic Liquids  

Microsoft Academic Search

The synthesis of D,L???tocopherol from trimethylhydroquinone and isophytol using the Brønsted acidic SO3H?functionalized ionic liquids as catalysts was explored. The catalytic activities of the SO3H?functionalized ionic liquids were dependent on their anions. The yield of D,L???tocopherol also depended on the solvent, which was the reaction medium. A yield of 94.3% was obtained using the SO3H?functionalized ionic liquid with [BF4

Huabing Xing; Tao Wang; Zhenhuan Zhou; Youyuan Dai

2006-01-01

367

A novel ionic liquid-tolerant Fusarium oxysporum BN secreting ionic liquid-stable cellulase: Consolidated bioprocessing of pretreated lignocellulose containing residual ionic liquid.  

PubMed

In this study, microbial communities from chemicals polluted microhabitats were cultured with the addition of imidazolium-based ionic liquid (IL) to enrich for IL-tolerant microbes. A strain of Fusarium oxysporum BN producing cellulase from these enrichments was capable of growing in 10% (w/v) 1-ethyl-3-methylimidazolium phosphinate, much higher than the normal IL concentrations in the lignocellulose regenerated from ILs. Cellulase secreted by the strain showed high resistance to ILs based on phosphate and sulfate radicals, evidencing of a high conformational stability in relevant media. Gratifyingly, F. oxysporum BN can directly convert IL-pretreated rice straw to bioethanol via consolidated bioprocessing (I-CBP). At optimum fermentation condition, a maximum ethanol yield of 0.125gethanolg(-1) of rice straw was finally obtained, corresponding to 64.2% of the theoretical yield. PMID:25625459

Xu, Jiaxing; Wang, Xinfeng; Hu, Lei; Xia, Jun; Wu, Zhen; Xu, Ning; Dai, Benlin; Wu, Bin

2015-04-01

368

Phase equilibrium in systems with ionic liquids: An example for the downstream process of the Biphasic Acid Scavenging utilizing Ionic Liquids (BASIL) process. Part I: Experimental data  

Microsoft Academic Search

Experimental results are presented for the (liquid+liquid), (solid+liquid) and (solid+liquid+liquid) equilibria occurring in the downstream process of a typical example for the Biphasic Acid Scavenging Utilizing Ionic Liquids (BASIL)-processes. In a BASIL process an organic base is used to catalyze a chemical reaction and, at the same time, to scavenge an acid that is an undesired side product of that

Katya Sahandzhieva; Gerd Maurer

369

Electrochemical transistors with ionic liquids for enzymatic sensing  

NASA Astrophysics Data System (ADS)

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.

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

370

Development of Ionic Liquid Monopropellants for In-Space Propulsion  

NASA Technical Reports Server (NTRS)

A family of new, low toxicity, high energy monopropellants is currently being evaluated at NASA Marshall Space Flight Center for in-space rocket engine applications such as reaction control engines. These ionic liquid monopropellants, developed in recent years by the Air Force Research Laboratory, could offer system simplification, less in-flight thermal management, and reduced handling precautions, while increasing propellant energy density as compared to traditional storable in-space propellants such as hydrazine and nitrogen tetroxide. However, challenges exist in identifying ignition schemes for these ionic liquid monopropellants, which are known to burn at much hotter combustion temperatures compared to traditional monopropellants such as hydrazine. The high temperature combustion of these new monopropellants make the use of typical ignition catalyst beds prohibitive since the catalyst cannot withstand the elevated temperatures. Current research efforts are focused on monopropellant ignition and burn rate characterization, parameters that are important in the fundamental understanding of the monopropellant behavior and the eventual design of a thruster. Laboratory studies will be conducted using alternative ignition techniques such as laser-induced spark ignition and hot wire ignition. Ignition delay, defined as the time between the introduction of the ignition source and the first sign of light emission from a developing flame kernel, will be measured using Schlieren visualization. An optically-accessible liquid monopropellant burner will be used to determine propellant burn rate as a function of pressure and initial propellant temperature. The burn rate will be measured via high speed imaging through the chamber s windows.

Blevins, John A.; Osborne, Robin; Drake, Gregory W.

2005-01-01

371

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

PubMed

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

Rout, Alok; Binnemans, Koen

2015-01-21

372

High current density electrodeposition from silver complex ionic liquids.  

PubMed

Liquid metal salts are electrolytes with the highest possible metal concentration for electrodeposition, because the metal ion is an integral part of the solvent. This paper introduces the new ionic silver complexes [Ag(MeCN)(4)](2)[Ag(Tf(2)N)(3)], [Ag(MeCN)][Tf(2)N] and [Ag(EtIm)(2)][Tf(2)N], where MeCN stands for acetonitrile, EtIm for 1-ethylimidazole and Tf(2)N is bis(trifluoromethylsulfonyl)imide. These complexes have been characterized by differential scanning calorimetry, single crystal X-ray crystallography, thermogravimetrical analysis, Raman spectroscopy and cyclic voltammetry. [Ag(MeCN)(4)](2)[Ag(Tf(2)N)(3)] is a room temperature ionic liquid. Smooth silver layers of good quality could be deposited from it, at current densities of up to 25 A dm(-2) in unstirred solutions. [Ag(EtIm)(2)][Tf(2)N] melts at 65 °C and can be used as an electrolyte for silver deposition above this temperature. [Ag(MeCN)][Tf(2)N] has a melting point that is too high to be useful in electrodeposition. Addition of thiourea or 1H-benzotriazole to the electrolyte decreased the surface roughness of the silver coatings. The morphology of the metal layers was investigated by atomic force microscopy (AFM). Adsorption of 1H-benzotriazole on the silver metal surface has been proven by Raman spectroscopy. This work shows the usefulness of additives in improving the quality of metal films electrodeposited from ionic liquids. PMID:22193991

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

2012-02-01

373

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

PubMed

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

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

2015-03-11

374

Acidic Ionic Liquids as Composite Forming Additives for Ion-conducting Materials  

NASA Astrophysics Data System (ADS)

This paper represents the material conductivity investigation of several AILs (Acidic Ionic Liquids) containing an alkane sulfonic acid group covalently bonded to pyridine and N-alkylimidazole cations. Three different anions (HSO4-, H2PO4- and TsO-) have been introduced in the structure of ionic liquids to evaluate the impact of this factor on material conductivity. Ion conductivity values in all studied ionic liquids obtained from impedance measurements in temperature range from 20 to 120 °C. Values of electroconductivity depending on ionic liquid's structure vary in rage from 1.34·10-5 to 1.05·10-2 S/cm at 25 °C.

Lasmane, L.; Ausekle, E.; Vaivars, G.; Priksane, A.

2013-12-01

375

Carboxyl-functionalized task-specific ionic liquids for solubilizing metal oxides.  

PubMed

Imidazolium, pyridinium, pyrrolidinium, piperidinium, morpholinium, and quaternary ammonium bis(trifluoromethylsulfonyl)imide salts were functionalized with a carboxyl group. These ionic liquids are useful for the selective dissolution of metal oxides and hydroxides. Although these hydrophobic ionic liquids are immiscible with water at room temperature, several of them form a single phase with water at elevated temperatures. Phase separation occurs upon cooling. This thermomorphic behavior has been investigated by (1)H NMR, and it was found that it can be attributed to the temperature-dependent hydration and hydrogen-bond formation of the ionic liquid components. The crystal structures of four ionic liquids and five metal complexes have been determined. PMID:18841931

Nockemann, Peter; Thijs, Ben; Parac-Vogt, Tatjana N; Van Hecke, Kristof; Van Meervelt, Luc; Tinant, Bernard; Hartenbach, Ingo; Schleid, Thomas; Ngan, Vu Thi; Nguyen, Minh Tho; Binnemans, Koen

2008-11-01

376

Design and Evaluation of Ionic Liquids as Novel CO2 Absorbents  

SciTech Connect

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

Edward Maginn

2007-07-15

377

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

SciTech Connect

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.

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

2012-01-01

378

Mechanical Properties of Composite SPEEK Polymer Membranes Modified with Ionic Liquids  

NASA Astrophysics Data System (ADS)

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.

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

2015-03-01

379

Electrospraying insulating liquids via charged nanodrop injection from the Taylor cone of an ionic liquid  

NASA Astrophysics Data System (ADS)

Charge is injected into the bulk of an insulating liquid in the form of nanodrops produced by an immersed Taylor cone of an ionic liquid. The charge then drifts onto the insulator surface, destabilizing it and leading to the formation of an electrified jet that atomizes into approximately monodisperse micron size insulator drops. The approach is similar to those previously based on field injection of ions from sharp tungsten tips, but the continuous renewal and self-sharpening of the liquid charge-injector permits long-term stable operation. Using heptane as the insulator and 1-ethyl-3-methylimidazolium-BF4 as the ionic liquid we produce approximately monodisperse drops with average diameters ranging from less than 4 up to 20 ?m, injecting in some cases as little as 0.0002% by volume of ionic liquid. No fundamental limitation restricting the possibility of forming even smaller drops is apparent. The scaling law of Kim and Turnbull ["Generation of charged drops of insulating liquids by electrostatic spraying," J. Appl. Phys. 47, 1964 (1976)] where the drop diameter varies as the 2/3 power of the liquid flow rate and the -2/3 power of the spray current is confirmed, implying that the drops are on the average charged to 50%-60% of the Rayleigh limit.

Larriba-Andaluz, Carlos; Fernández de la Mora, Juan

2010-07-01

380

Synthesis and anti-microbial activity of hydroxylammonium ionic liquids.  

PubMed

Eight hydroxylammonium-based room temperature ionic liquids (ILs) have been synthesized by acid-base neutralization of ethanolamines with organic acids. The ILs were characterized by infrared and nuclear magnetic resonance spectroscopies and elemental analysis. Their anti-microbial activities were determined using the well-diffusion method. All eight ILs were toxic to Staphylococcus aureus, while 2-hydroxyethylammonium lactate and 2-hydroxy-N-(2-hydroxyethyl)-N-methylethanaminium acetate showed high anti-microbial activity against a wide range of human pathogens. PMID:21421256

Ismail Hossain, M; El-Harbawi, Mohanad; Noaman, Yousr Abdulhadi; Bustam, Mohd Azmi B; Alitheen, Noorjahan Banu Mohamed; Affandi, Nor Azrin; Hefter, Glenn; Yin, Chun-Yang

2011-06-01

381

New, ionic liquid-based membranes for lithium battery application  

Microsoft Academic Search

New types of dimensionally stable, flexible gel-type electrolyte membranes with a relatively wide electrochemical stability, high lithium ion conductivity and other desirable properties have been prepared by immobilizing N-n-butyl-N-ethylpyrrolidinium N,N-bis(trifluoromethane)sulfonimide-lithium N,N-bis(trifluoromethane)sulfonimide (Py24TFSI-LiTFSI), ionic liquid, IL, solutions in a poly(vinylidene fluoride)-hexafluoropropylene copolymer (PVdF-HFP) matrix. The addition of a discrete amount of ethylene and propylene carbonate (EC–PC), solvent mixture to the membranes

C. Sirisopanaporn; A. Fernicola; B. Scrosati

2009-01-01

382

Additive-containing ionic liquid electrolytes for secondary lithium battery  

Microsoft Academic Search

Room temperature ionic liquid (RTIL) consisting of N-methyl-N-propylpiperidinium (PP13) cation and bis(trifluoromethanesulfonyl)imide (TFSI) anion was synthesized and its electrochemical stability was investigated in comparison with 1-butyl-3-methylimidazolium tetrafluoroborate (BMIBF4) and 1-butyl-3-methylimidazolium hexafluorophosphate (BMIPF6). The electrochemical window of PP13-TFSI (5.8V versus Li\\/Li+) is wider than that of BMIBF4 (4.7V) and BMIPF6 (4.5V). The cathodic limit of the PP13-TFSI is about ?0.3V versus

Jinqiang Xu; Jun Yang; Yanna NuLi; Jiulin Wang; Zongshuang Zhang

2006-01-01

383

Analysis of mono- and oligosaccharides in ionic liquid containing matrices.  

PubMed

Ionic liquids (ILs), that is, salts with melting points <100°C, have recently attracted a lot of attention in biomass processing due to their ability to dissolve lignocellulosics. In this work, we studied how two imidazolium-based, hydrophilic, cellulose dissolving ionic liquids 1,3-dimethylimidazolium dimethylphosphate [DMIM]DMP and 1-ethyl-3-methylimidazolium acetate [EMIM]AcO affect the usually employed analytical methods for mono- and oligosaccharides, typical products from hydrolytic treatments of biomass. HPLC methods were severely hampered by the presence of ILs with loss of separation power and severe baseline problems, making their use for saccharide quantification extremely challenging. Problems in DNS photometric assay and chromatography were also encountered at high ionic liquid concentrations and many capillary electrophoresis (CE) methods did not allow an efficient analysis of saccharides in these matrices. In this paper we describe an optimized CE method with pre-column derivatization for the qualitative and quantitative analysis of mono- and oligosaccharides in sample matrices containing moderate (20-40% (v/v)) concentrations of ILs. The IL content and type in the sample matrix was found to affect both peak shape and quantification parameters. Generally, the presence of high IL concentrations (?20% (v/v)) had a dampening effect on the detection of the analytes. IL in lower concentrations of <20% (v/v) was, however, found to improve peak shape and/or separation in some cases. The optimized CE method has good sensitivity in moderate concentrations of the ionic liquids used, with limits of detection of 5mg/L for cellooligomers up to the size of cellotetraose and 5-20mg/L for cellopentaose and cellohexaose, depending on the matrix. The method was used for analysing the action of a commercial ?-glucosidase in ILs and for analysing saccharides in the IL containing hydrolysates from the hydrolysis of microcrystalline cellulose with Trichoderma reesei endoglucanase Cel5A. According to the results, [DMIM]DMP and [EMIM]AcO] showed clear differences in enzyme inactivation. PMID:23583452

Wahlström, Ronny; Rovio, Stella; Suurnäkki, Anna

2013-05-24

384

Block Copolymer Micelle Shuttles between Water and Ionic Liquids  

NASA Astrophysics Data System (ADS)

The micelle shuttle is an interesting phenomenon recently discovered by our group: a reversible and intact migration of poly(butadiene- b-ethylene oxide) (PB-PEO) block copolymer micelles between water and a hydrophobic ionic liquid upon a simple temperature stimulus. The micelles allow for encapsulation of cargo molecules and the transfer enables control of their partitioning in the biphasic system. This simple round-trip delivery system can be used in delivery, reaction, and separations in synthesis and biphasic catalysis using ionic liquids. This thesis is aimed to systematically study the components, features, mechanism and possible applications of the micelle shuttle. For study on the components, several block copolymers and ionic liquids were employed to demonstrate the micelle shuttle, indicating the generality of the phenomenon. To control the loading and release of the micelle nanocarriers in the biphasic system, a thermoreversible micellization-transfer-demicellization shuttle was developed using a multiply thermosensitive block copolymer. The micelle shuttle was also demonstrated using micelles with different nanostructures, including spheres, cylinders, and vesicles. In particular, a new class of vesicles with ionic liquid interiors dispersed in water was developed using a vesicle shuttle. Permeability studies reflect the reasonably permeable membrane of the vesicles, which is desirable for potential applications of these responsive and stable vesicles as recyclable nanoreactors. As for research into the features, reversible and quantitative transfer appeared to be a common characteristic of the micelle shuttle. A strong temperature dependence of the micelle distribution in the biphasic system was observed, which is favorable for controlled delivery using the micelle shuttle. The transfer temperature determining the micelle partitioning in the biphasic system could be effectively tuned by simply using additives in the aqueous phase. To understand the transfer mechanism, the driving force, thermodynamics and kinetics of the micelle shuttle were investigated in detail utilizing shuttles of PEO homopolymers and dye-loaded PB-PEO micelles. A detailed multiple-step transfer mechanism was then proposed. To demonstrate possible applications, micelles formed by the commercial and inexpensive Pluronic block copolymer were employed as nanocarriers for delivery and extraction in the biphasic system. The vesicle shuttle was also utilized to transport various dyes in the biphasic system.

Bai, Zhifeng

385

Hydrogen Fluoride Capture by Imidazolium Acetate Ionic Liquid  

E-print Network

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.

Chaban, Vitaly

2015-01-01

386

Regenerating cellulose from ionic liquids for an accelerated enzymatic hydrolysis  

SciTech Connect

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.

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

387

Synthesis of cellulose methylcarbonate in ionic liquids using dimethylcarbonate.  

PubMed

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

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

2015-01-01

388

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

PubMed Central

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.

Hainstock, Michael L.; Tang, Yijun

2015-01-01

389

Lithium cation conducting TDI anion-based ionic liquids.  

PubMed

In this paper we present the synthesis route and electrochemical properties of new class of ionic liquids (ILs) obtained from lithium derivate TDI (4,5-dicyano-2-(trifluoromethyl)imidazolium) anion. ILs synthesized by us were EMImTDI, PMImTDI and BMImTDI, i.e. TDI anion with 1-alkyl-3-methylimidazolium cations, where alkyl meant ethyl, propyl and butyl groups. TDI anion contains fewer fluorine atoms than LiPF6 and thanks to C-F instead of P-F bond, they are less prone to emit fluorine or hydrogen fluoride due to the rise in temperature. Use of IL results in non-flammability, which is making such electrolyte even safer for both application and environment. The thermal stability of synthesized compounds was tested by DSC and TGA and no signal of decomposition was observed up to 250 °C. The LiTDI salt was added to ILs to form complete electrolytes. The structures of tailored ILs with lithium salt were confirmed by X-ray diffraction patterns. The electrolytes showed excellent properties regarding their ionic conductivity (over 3 mS cm(-1) at room temperature after lithium salt addition), lithium cation transference number (over 0.1), low viscosity and broad electrochemical stability window. The ionic conductivity and viscosity measurements of pure ILs are reported for reference. PMID:24803282

Niedzicki, Leszek; Karpierz, Ewelina; Zawadzki, Maciej; Dranka, Maciej; Kasprzyk, Marta; Zalewska, Aldona; Marcinek, Marek; Zachara, Janusz; Doma?ska, Urszula; Wieczorek, W?adys?aw

2014-06-21

390

Development of Ionic Liquid Monopropellants for In-Space Propulsion  

NASA Technical Reports Server (NTRS)

A family of new, low toxicity, high energy monopropellants is currently being evaluated at NASA Marshall Space Flight Center for in-space rocket engine applications such as reaction control engines. These ionic liquid monopropellants, developed in recent years by the Air Force Research Laboratory, could offer system simplification, less in-flight thermal management, and reduced handling precautions, while increasing propellant energy density as compared to traditional storable in-space propellants such as hydrazine and nitrogen tetroxide. However, challenges exist in identifying ignition schemes for these ionic liquid monopropellants, which are known to burn at much hotter combustion temperatures compared to traditional monopropellants such as hydrazine. The high temperature combustion of these new monopropellants make the use of typical ignition catalyst beds prohibitive since the catalyst cannot withstand the elevated temperatures. Current research efforts are focused on monopropellant ignition and burn rate characterization, parameters that are important in the fundamental understanding of the monopropellant behavior and the eventual design of a thruster. Laboratory studies will be conducted using alternative ignition techniques such as laser-induced spark ignition and hot wire ignition. Ignition delay, defined as the time between the introduction of the ignition source and the first sign of light emission from a developing flame kernel, will be measured using Schlieren visualization. An optically-accessible liquid monopropellant burner, shown schematically in Figure 1 and similar in design to apparatuses used by other researchers to study solid and liquid monopropellants, will be used to determine propellant burn rate as a function of pressure and initial propellant temperature. The burn rate will be measured via high speed imaging through the chamber s windows.

Blevins, John A.; Drake, Gregory W.; Osborne, Robin J.

2005-01-01

391

Photochromic imidazolium based ionic liquids based on spiropyran.  

PubMed

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

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

2010-07-14

392

Surface confined ionic liquid as a stationary phase for HPLC  

SciTech Connect

Trimethoxysilane ionosilane derivatives of room temperature ionic liquids based on alkylimidazolium bromides were synthesized for attachment to silica support material. The derivatives 1-methyl-3-(trimethoxysilylpropyl)imidazolium bromide and 1-butyl-3-(trimethoxysilylpropyl)imidazolium bromide were used to modify the surface of 3 {micro}m diameter silica particles to act as the stationary phase for HPLC. The modified particles were characterized by thermogravimetric analysis (TGA) and {sup 13}C and {sup 29}Si NMR spectroscopies. The surface modification procedure rendered particles with a surface coverage of 0.84 {micro}mol m{sup -2} for the alkylimidazolium bromide. The ionic liquid moiety was predominantly attached to the silica surface through two siloxane bonds of the ionosilane derivative (63%). Columns packed with the modified silica material were tested under HPLC conditions. Preliminary evaluation of the stationary phase for HPLC was performed using aromatic carboxylic acids as model compounds. The separation mechanism appears to involve multiple interactions including ion exchange, hydrophobic interaction, and other electrostatic interactions.

Wang, Qian [University of Buffalo, The State University of New York; Baker, Gary A [ORNL; Baker, Sheila N [ORNL; Colon, Luis [Los Alamos National Laboratory (LANL)

2006-01-01

393

Spatial-decomposition analysis of electrical conductivity in ionic liquid  

NASA Astrophysics Data System (ADS)

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.

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

2014-12-01

394

Polarizability effects on the structure and dynamics of ionic liquids  

NASA Astrophysics Data System (ADS)

Polarization effects on the structure and dynamics of ionic liquids are investigated using molecular dynamics simulations. Four different ionic liquids were simulated, formed by the anions Cl- and PF6-, treated as single fixed charge sites, and the 1-n-alkyl-3-methylimidazolium cations (1-ethyl and 1-butyl-), which are polarizable. The partial charge fluctuation of the cations is provided by the electronegativity equalization model (EEM) and a complete parameter set for the cations electronegativity (?) and hardness (J) is presented. Results obtained from a non-polarizable model for the cations are also reported for comparison. Relative to the fixed charged model, the equilibrium structure of the first solvation shell around the imidazolium cations shows that inclusion of EEM polarization forces brings cations closer to each other and that anions are preferentially distributed above and below the plane of the imidazolium ring. The polarizable model yields faster translational and reorientational dynamics than the fixed charges model in the rotational-diffusion regime. In this sense, the polarizable model dynamics is in better agreement with the experimental data.

Cavalcante, Ary de Oliveira; Ribeiro, Mauro C. C.; Skaf, Munir S.

2014-04-01

395

Coordination of terpyridine to Li+ in two different ionic liquids.  

PubMed

On the basis of (7)Li NMR experiments, the complex-formation reaction between Li(+) and the tridentate N-donor ligand terpyridine was studied in the ionic liquids [emim][NTf2] and [emim][ClO4] as solvents. For both ionic liquids, the NMR data implicate the formation of [Li(terpy)2](+). Density functional theory calculations show that partial coordination of terpyridine involving the coordination of a solvent anion can be excluded. In contrast to the studies in solution, X-ray diffraction measurements led to completely different results. In the case of [emim][NTf2], the polymeric lithium species [Li(terpy)(NTf2)]n was found to control the stacking of this complex, whereas crystals grown from [emim][ClO4] exhibit the discrete dimeric species [Li(terpy)(ClO4)]2. However, both structures indicate that each lithium ion is formally coordinated by one terpy molecule and one solvent anion in the solid state, suggesting that charge neutralization and ? stacking mainly control the crystallization process. PMID:24187986

Pokorny, Klaus; Schmeisser, Matthias; Hampel, Frank; Zahl, Achim; Puchta, Ralph; van Eldik, Rudi

2013-11-18

396

Interactions of Ionic Liquids with Uranium and its Bioreduction  

SciTech Connect

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].

Zhang, C.; Francis, A.

2012-09-18

397

Ionic liquid/water mixtures: from hostility to conciliation.  

PubMed

Water was originally inimical to ionic liquids (ILs) especially in the analysis of their detailed properties. Various data on the properties of ILs indicate that there are two ways to design functions of ionic liquids. The first is to change the structure of component ions, to provide "task-specific ILs". The second is to mix ILs with other components, such as other ILs, organic solvents or water. Mixing makes it easy to control the properties of the solution. In this strategy, water is now a very important partner. Below, we summarise our recent results on the properties of IL/water mixtures. Stable phase separation is an effective method in some separation processes. Conversely, a dynamic phase change between a homogeneous mixture and separation of phases is important in many fields. Analysis of the relation between phase behaviour and the hydration state of the component ions indicates that the pattern of phase separation is governed by the hydrophilicity of the ions. Sufficiently hydrophilic ions yielded ILs that are miscible with water, and hydrophobic ions gave stable phase separation with water. ILs composed of hydrophobic but hydrated ions undergo a dynamic phase change between a homogeneous mixture and separate phases according to temperature. ILs having more than seven water molecules per ion pair undergo this phase transition. These dynamic phase changes are considered, with some examples, and application is made to the separation of water-soluble proteins. PMID:22683915

Kohno, Yuki; Ohno, Hiroyuki

2012-07-21

398

Using Ionic Liquids in Selective Hydrocarbon Conversion Processes  

SciTech Connect

This is the Final Report of the five-year project Using Ionic Liquids in Selective Hydrocarbon Conversion Processes (DE-FC36-04GO14276, July 1, 2004- June 30, 2009), in which we present our major accomplishments with detailed descriptions of our experimental and theoretical efforts. Upon the successful conduction of this project, we have followed our proposed breakdown work structure completing most of the technical tasks. Finally, we have developed and demonstrated several optimized homogenously catalytic methane conversion systems involving applications of novel ionic liquids, which present much more superior performance than the Catalytica system (the best-to-date system) in terms of three times higher reaction rates and longer catalysts lifetime and much stronger resistance to water deactivation. We have developed in-depth mechanistic understandings on the complicated chemistry involved in homogenously catalytic methane oxidation as well as developed the unique yet effective experimental protocols (reactors, analytical tools and screening methodologies) for achieving a highly efficient yet economically feasible and environmentally friendly catalytic methane conversion system. The most important findings have been published, patented as well as reported to DOE in this Final Report and our 20 Quarterly Reports.

Tang, Yongchun; Periana, Roy; Chen, Weiqun; van Duin, Adri; Nielsen, Robert; Shuler, Patrick; Ma, Qisheng; Blanco, Mario; Li, Zaiwei; Oxgaard, Jonas; Cheng, Jihong; Cheung, Sam; Pudar, Sanja

2009-09-28

399

Development of an Ionic-Liquid Absorption Heat Pump  

SciTech Connect

Solar Fueled Products (SFP) is developing an innovative ionic-liquid absorption heat pump (ILAHP). The development of an ILAHP is extremely significant, as it could result in annual savings of more than 190 billion kW h of electrical energy and $19 billion. This absorption cooler uses about 75 percent less electricity than conventional cooling and heating units. The ILAHP also has significant environmental sustainability benefits, due to reduced CO2 emissions. Phase I established the feasibility and showed the economic viability of an ILAHP with these key accomplishments: • Used the breakthrough capabilities provided by ionic liquids which overcome the key difficulties of the common absorption coolers. • Showed that the theoretical thermodynamic performance of an ILAHP is similar to existing absorption-cooling systems. • Established that the half-effect absorption cycle reduces the peak generator temperature, improving collector efficiency and reducing collector area. • Component testing demonstrated that the most critical components, absorber and generator, operate well with conventional heat exchangers. • Showed the economic viability of an ILAHP. The significant energy savings, sustainability benefits, and economic viability are compelling reasons to continue the ILAHP development.

Holcomb, Don

2011-03-29

400

Polarizability effects on the structure and dynamics of ionic liquids  

SciTech Connect

Polarization effects on the structure and dynamics of ionic liquids are investigated using molecular dynamics simulations. Four different ionic liquids were simulated, formed by the anions Cl{sup ?} and PF{sub 6}{sup ?}, treated as single fixed charge sites, and the 1-n-alkyl-3-methylimidazolium cations (1-ethyl and 1-butyl-), which are polarizable. The partial charge fluctuation of the cations is provided by the electronegativity equalization model (EEM) and a complete parameter set for the cations electronegativity (?) and hardness (J) is presented. Results obtained from a non-polarizable model for the cations are also reported for comparison. Relative to the fixed charged model, the equilibrium structure of the first solvation shell around the imidazolium cations shows that inclusion of EEM polarization forces brings cations closer to each other and that anions are preferentially distributed above and below the plane of the imidazolium ring. The polarizable model yields faster translational and reorientational dynamics than the fixed charges model in the rotational-diffusion regime. In this sense, the polarizable model dynamics is in better agreement with the experimental data.

Cavalcante, Ary de Oliveira, E-mail: arycavalcante@ufam.edu.br [Institute of Chemistry, University of Campinas – UNICAMP, Cx. P. 6154, Campinas, SP 13084-862 (Brazil); Departamento de Química, Universidade Federal do Amazonas, Av. Rodrigo Octávio, 6200, Coroado, Manaus, AM (Brazil); Ribeiro, Mauro C. C. [Laboratório de Espectroscopia Molecular, Instituto de Química, Universidade de São Paulo, São Paulo, SP C.P. 26077, 05513 970 São Paulo, SP (Brazil)] [Laboratório de Espectroscopia Molecular, Instituto de Química, Universidade de São Paulo, São Paulo, SP C.P. 26077, 05513 970 São Paulo, SP (Brazil); Skaf, Munir S. [Institute of Chemistry, University of Campinas – UNICAMP, Cx. P. 6154, Campinas, SP 13084-862 (Brazil)] [Institute of Chemistry, University of Campinas – UNICAMP, Cx. P. 6154, Campinas, SP 13084-862 (Brazil)

2014-04-14

401

Ionic liquids and ultrasound in combination: synergies and challenges.  

PubMed

Ionic liquids, as reaction media, and sonochemistry are two recently developing fields of chemistry that present some similarities. Firstly, they constitute separately unconventional approaches to reaction chemistry that, in many cases, generate improvements in yield, rate and selectivity compared to classical chemistry, or even change the mechanisms or products expected. In addition, both are often associated with green chemistry concepts as a result of their properties and their possible eco-friendly uses. A recent trend has been to combine these two technologies in a range of different applications and the results demonstrate very significant and occasionally surprising synergetic effects. Here we critically review the advantages and limitations of the ionic liquid/ultrasound combination in different applications in chemistry, to understand how, and in which respects, it could become an essential tool of sustainable chemistry in the future. Many practical and theoretical aspects associated with this combination of techniques are not understood or resolved and we discus where fundamental studies might further advance this field. PMID:25198613

Chatel, G; MacFarlane, D R

2014-12-01

402

Sorption of imidazolium-based ionic liquids to aquatic sediments.  

PubMed

Ionic liquids (ILs) have received much attention as "green" alternatives to traditional solvents because they do not evaporate, eliminating concerns over fugitive emissions. However, if ionic liquids are used in industrial applications, they may enter aquatic systems via effluent, and their fate and transport may be influenced by sorption to sediments. In this study, we conducted batch mixing experiments with four alkylmethylimidizolium-based ILs and four types of aquatic sediments to asses the capacity for natural aquatic sediments to remove these chemicals from the water column. The concentration isotherms were non linear with point estimates of the distribution coefficient (K(d)) decreasing with increasing concentration. Apparent distribution coefficients ranged from 7.9 to 95.7l kg(-1) at an initial concentration of 0.5mM and were positively related to sediment organic matter (SOM) content. These K(d) values indicate that the ILs did not sorb strongly to the tested sediments. Increased alkyl chain length did not lead to increased sorption suggesting that hydrophobic interactions were not the most important sorption mechanism. We conclude that aquatic sediments have a limited capacity to sorb alkylmethylimidazolium ILs and that the transport of these contaminants in aquatic systems will not be strongly attenuated by sediments. PMID:17850845

Beaulieu, J J; Tank, J L; Kopacz, M

2008-01-01

403

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

SciTech Connect

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.

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

2007-06-25

404

Investigation of Carbon-2 Substituted Imidazoles and Their Corresponding Ionic Liquids  

SciTech Connect

The functionality at the C-2 position of the imidazole ring plays a key role in defining the chemical properties of the imidazoles and their corresponding ionic liquids. Imidazoles 1 6 with different C-2 functionality were synthesized and their corresponding ionic liquids were systematically investigated. Based on their physical properties the six imidazoles can be divided into three groups. 1) The imidazoles 2 and 3 are capable of self-polymerization to form poly(ionic liquid)s, and they are characterized with a strong leaving group at the C-2 position. 2) The imidazoles 4 and 5 can form ionic liquids, but they are very sensitive to moisture. 3) The imidazoles 1 and 6 can form stable ionic liquids, and their stabilities were influenced by the electronic effects of the substituents at the C-2 position.

Liao, Chen [ORNL; Xiang, Zhu [University of Tennessee, Knoxville (UTK); Sun, Xiao-Guang [ORNL; Dai, Sheng [ORNL

2011-01-01

405

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

E-print Network

Ionic liquids (IL) are salts which are liquid at low temperatures, typically with melting points under 100 °C. In recent years ILs have been treated as novel solvents and used in a wide variety of applications such as ...

Gray, Andrew Peter

2012-06-22

406

New short aliphatic chain ionic liquids: synthesis, physical properties, and catalytic activity in aldol condensations.  

PubMed

This paper reports on the synthesis of new short aliphatic chain ionic liquids and the study of the temperature dependence of density, ultrasonic velocities, and ionic conductivity in the range of 278.15-338.15 K. Fourier transform infrared spectra establishes their simple ionic salt structure. Because of their polarity, the ionic liquids are able to dissolve polar solvents and inorganic salts, all of them showing high tolerance in hydroxylic media. The observed temperature trend of the studied properties points out the special packing of these ionic liquids, as well as the strong influence of the steric hindrance among linear aliphatic residues enclosed in anions and cations. One of them showed a very high melting temperature. A collection of slightly basic ionic liquids were used to test their catalytic activity in several aldol condensation reactions of some carbonyl compounds. The best conversions and selectivities were obtained using single ionic liquids, with no synergetic effects being observed when different concentrations of mixed ionic liquids were used as catalysts. In any case, the ionic liquid can also easily be recycled from reaction media, suggesting a promising method of process design for this kind of reaction. PMID:17918990

Cota, I; Gonzalez-Olmos, R; Iglesias, M; Medina, F

2007-11-01

407

Ionic Liquids and New Proton Exchange Membranes for Fuel Cells  

NASA Technical Reports Server (NTRS)

There is currently a great surge of activity in fuel cell research as laboratories across the world seek to take advantage of the high energy capacity provided by &el cells relative to those of other portable electrochemical power systems. Much of this activity is aimed at high temperature fie1 cells, and a vital component of such &el cells must be the availability of a high temperature stable proton-permeable membrane. NASA Glenn Research Center is greatly involved in developing this technology. Other approaches to the high temperature fuel cell involve the use of single- component or almost-single-component electrolytes that provide a path for protons through the cell. A heavily researched case is the phosphoric acid fuel cell, in which the electrolyte is almost pure phosphoric acid and the cathode reaction produces water directly. The phosphoric acid fie1 cell delivers an open circuit voltage of 0.9 V falling to about 0.7 V under operating conditions at 170 C. The proton transport mechanism is mainly vehicular in character according to the viscosity/conductance relation. Here we describe some Proton Transfer Ionic Liquids (PTILs) with low vapor pressure and high temperature stability that have conductivities of unprecedented magnitude for non-aqueous systems. The first requirement of an ionic liquid is that, contrary to experience with most liquids consisting of ions, it must have a melting point that is not much above room temperature. The limit commonly suggested is 100 C. PTILs constitute an interesting class of non-corrosive proton-exchange electrolyte, which can serve well in high temperature (T = 100 - 250 C) fuel cell applications. We will present cell performance data showing that the open circuit voltage output, and the performance of a simple H2(g)Pt/PTIL/Pt/O2(g) fuel cell may be superior to those of the equivalent phosphoric acid electrolyte fuel cell both at ambient temperature and temperatures up to and above 200 C. My work at NASA Glenn Research Center during this summer is to develop and characterize proton exchange membranes doped with ionic liquids. The main techniques used to characterize these materials are: Impedance Spectroscopy, NMR, DSC, TGA, DMA, IR, and SEM ...

Belieres, Jean-Philippe

2004-01-01

408

Ionic liquids containing carbonate solvent as electrolytes for lithium ion cells  

Microsoft Academic Search

A novel aliphatic quaternary ammonium type ionic liquid, N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(trifluoromethylsulfonyl)imide (DEME–TFSI), is a practical and useful ionic liquid as an electrolyte for electrochemical devices. Its desirable properties include non-flammability, a quite wide potential window (5.4V), and a high ionic conductivity (4.0mScm?1 at 30°C). We attempted to utilize Li-binary ionic liquids composed of LiTFSI and DEME–TFSI as an electrolyte in a

Takaya Sato; Tatsuya Maruo; Shoko Marukane; Kentaro Takagi

2004-01-01

409

Enhanced electrical transport in ionic liquid dispersed TMAI-PEO solid polymer electrolyte  

NASA Astrophysics Data System (ADS)

A polymer composite is prepared by dispersing ionic liquid [Bmim][BF4] in Polyethylene oxide-tetra methyl ammonium iodide composite and subsequent microwave treatment. X-ray diffraction patterns confirm the composite nature. To explore possibility of proton conductivity in these films, electrical transport is studied by impedance spectroscopy and DC polarization. It is revealed that addition of ionic liquid in host TMAI-PEO solid polymer electrolyte enhances the conductivity by ˜ 2 orders of magnitude. Polarization measurements suggest that composites are essentially ion conducting in nature. The maximum ionic conductivity is found to be ˜2 × 10-5 for 10 wt % ionic liquid.

Gupta, Neha; Rathore, Munesh; Dalvi, Anshuman; Kumar, Anil

2014-04-01

410

Lithium ion conductive behavior of TiO2 nanotube/ionic liquid matrices  

PubMed Central

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

2014-01-01

411

Enhanced electrical transport in ionic liquid dispersed TMAI-PEO solid polymer electrolyte  

SciTech Connect

A polymer composite is prepared by dispersing ionic liquid [Bmim][BF{sub 4}] in Polyethylene oxide-tetra methyl ammonium iodide composite and subsequent microwave treatment. X-ray diffraction patterns confirm the composite nature. To explore possibility of proton conductivity in these films, electrical transport is studied by impedance spectroscopy and DC polarization. It is revealed that addition of ionic liquid in host TMAI-PEO solid polymer electrolyte enhances the conductivity by ? 2 orders of magnitude. Polarization measurements suggest that composites are essentially ion conducting in nature. The maximum ionic conductivity is found to be ?2 × 10{sup ?5} for 10 wt % ionic liquid.

Gupta, Neha [Physics Department, Birla Institute of Technology and Science, Pilani-333031, Rajasthan, India and Department of Physics, JECRC University, Jaipur-303905, Rajasthan (India); Rathore, Munesh, E-mail: adalvi@pilani.bits-pilani.ac.in; Dalvi, Anshuman, E-mail: adalvi@pilani.bits-pilani.ac.in [Physics Department, Birla Institute of Technology and Science, Pilani-333031, Rajasthan (India); Kumar, Anil [Chemistry Department, Birla Institute of Technology and Science, Pilani-333031, Rajasthan (India)

2014-04-24

412

Stokes shift dynamics of [Na][TOTO] A new class of ionic liquids: A comparative study with more common imidazolium analogs  

E-print Network

Stokes shift dynamics of [Na][TOTO] ­ A new class of ionic liquids: A comparative study with more ([Na][TOTO]), and compared with imidazo- lium ionic liquids (ILs). Predicted dynamic Stokes shift, particularly for ionic liquids where comp

Biswas, Ranjit

413

Facile and scalable synthesis of nanoporous materials based on poly(ionic liquid)s.  

PubMed

A simple, fast, sustainable, and scalable strategy to prepare nanoporous materials based on poly(ionic liquid)s (PILs) is presented. The synthetic strategy relies on the radical polymerization of crosslinker-type ionic liquid (IL) monomers in the presence of an analogous IL, which acts as a porogenic solvent. This IL can be extracted easily after polymerization and recycled for further use. The great advantages of this synthetic approach are the atom-efficiency and lack of waste. The effects of different monomer/porogen ratios on the specific surface area, porosity, and pore size have been investigated. Finally, the potential of the materials as CO2 sorbents has been evaluated. PMID:25220614

Azcune, Itxaso; García, Ignacio; Carrasco, Pedro M; Genua, Aratz; Tanczyk, Marek; Jaschik, Manfred; Warmuzinski, Krzysztof; Cabañero, Germán; Odriozola, Ibon

2014-12-01

414

Ionic liquids in soils: effects of different anion species of imidazolium based ionic liquids on wheat ( Triticum aestivum ) as affected by different clay minerals and clay concentrations  

Microsoft Academic Search

This study contributes to a prospective hazard assessment of ionic liquids, focusing on the terrestrial environment. The influence\\u000a of differently composed soils—varying contents of the clay minerals smectite and kaolinite—on the toxicity of different anion\\u000a species of imidazolium based ionic liquids was studied for growth inhibition of wheat (Triticum aestivum). IM14 (CF3SO2)2N appeared the most toxic, independently of the investigated

Marianne Matzke; Stefan Stolte; Jürgen Arning; Ute Uebers; Juliane Filser

2009-01-01

415

Synthesis and characterization of two ionic liquids with emphasis on their chemical stability towards metallic lithium  

Microsoft Academic Search

Two room temperature ionic liquids (RTILs) without acidic protons, based on different cationic species (1-n-butyl-2,3-dimethylimidazolium) (BMMI) and N-n-butyl-N-methylpiperidinium (BMP) using (CF3SO2)2N? (TFSI) as anion, were prepared by quaternization of their respective amines with an appropriate alkyl halide, followed by ion exchange reaction. All relevant properties of these ionic liquids, such as, thermal stability, density, viscosity, electrochemical behavior, ionic conductivity and

Fernanda F. C. Bazito; Yoshio Kawano; Roberto M. Torresi

2007-01-01

416

A neat ionic liquid electrolyte based on FSI anion for electric double layer capacitor  

Microsoft Academic Search

An ionic liquid, 1-ethyl-3-methyl imidazolium bis(fluorosulfonyl)imide (EMI-FSI), has been applied to an electrolyte for electric double layer capacitors (EDLCs). The electrolyte exhibited high ionic conductivity comparable to that of a conventional organic electrolyte. EDLC prepared with EMI-FSI showed excellent rate capability although the electrolyte is a neat ionic liquid; this performance was observed irrespective of the presence of a binder

Norihisa Handa; Toshinori Sugimoto; Masaki Yamagata; Manabu Kikuta; Michiyuki Kono; Masashi Ishikawa

2008-01-01

417

Low-frequency Raman spectra and fragility of imidazolium ionic liquids  

SciTech Connect

Raman spectra within the 5-200 cm{sup -1} range have been recorded as a function of temperature for different ionic liquids based on imidazolium cations. A correlation has been found between fragility and the temperature dependence of the strength of fast relaxational motions. Understanding quasielastic scattering as the relaxational contribution to ionic mean-squared displacement elucidates some effects on ionic liquids' fragility resulting from modifications in the chemical structure.

Ribeiro, Mauro C. C. [Laboratorio de Espectroscopia Molecular, Instituto de Quimica, Universidade de Sao Paulo, CP 26077, CEP 05513-970 Sao Paulo, Sao Paulo (Brazil)

2010-07-14

418

Technical Highlights for July 2012 New Collaboration Underway to Investigate Ionic Liquids for Enhancing Engine Efficiency  

E-print Network

for Enhancing Engine Efficiency A new Cooperative Research and Development Agreement (CRADA), No. NFE-12) #0000239 award, "Ionic Liquids as Multi-Functional Lubricant Additives to Enhance Engine Efficiency-soluble ionic liquids as engine oil additives to substantially improve the mechanical efficiency of internal

419

Ionic liquids as electrolytes for Li-ion batteries—An overview of electrochemical studies  

Microsoft Academic Search

The paper reviews properties of room temperature ionic liquids (RTILs) as electrolytes for lithium and lithium-ion batteries. It has been shown that the formation of the solid electrolyte interface (SEI) on the anode surface is critical to the correct operation of secondary lithium-ion batteries, including those working with ionic liquids as electrolytes. The SEI layer may be formed by electrochemical

Andrzej Lewandowski; Agnieszka ?widerska-Mocek

2009-01-01

420

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

Microsoft Academic Search

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

Shinichi Komaba; Naoaki Yabuuchi; Yasushi Katayama; Takashi Miura

2010-01-01

421

Ionic Liquids as an Attractive Alternative Solvent for Thermal Lens Measurements  

E-print Network

Ionic Liquids as an Attractive Alternative Solvent for Thermal Lens Measurements Chieu D. Tran, Wisconsin 53201-1881 The use of ionic liquids (ILs) as a solvent for thermal lens measurements has been investigated. It was found that ILs provide a better medium for thermal lens measure- ments than water

Reid, Scott A.

422

Visualization of Biomass Solubilization and Cellulose Regeneration during Ionic Liquid Pretreatment of Switchgrass  

Technology Transfer Automated Retrieval System (TEKTRAN)

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-methylimid...

423

Novel ionic liquid supported synthesis of platinum-based electrocatalysts on multiwalled carbon nanotubes  

Microsoft Academic Search

Novel ionic liquids (ILs) were used to prepare carbon nanotube (CNT) supported platinum catalysts for the first time. The CNTs were pretreated in acid to get functional groups to promote the adherence of Pt nanoparticles. Ionic liquids added to the reaction system are suggested to contribute to the formation of homogeneous small Pt nanoparticles and to suppress the agglomeration of

Z. W. Zhao; Z. P. Guo; J. Ding; D. Wexler; Z. F. Ma; D. Y. Zhang; H. K. Liu

2006-01-01

424

Polyanionic and polyzwitterionic azobenzene ionic liquid-functionalized silica materials and their chromatographic applications.  

PubMed

New polyanionic and polyzwitterionic azobenzene ionic liquid-functionalized silica materials were designed based on the preparation of a new polymerizable azobenzene anionic monomer and either its cation-exchange with alkylimidazolium after grafting or the formation of an ionic liquid monomer pair before grafting onto silica. PMID:23417018

Qiu, Hongdeng; Jiang, Shengxiang; Takafuji, Makoto; Ihara, Hirotaka

2013-03-25

425

Comparison of three ionic liquid-tolerant cellulases by molecular dynamics.  

PubMed

We have employed molecular dynamics to investigate the differences in ionic liquid tolerance among three distinct family 5 cellulases from Trichoderma viride, Thermogata maritima, and Pyrococcus horikoshii. Simulations of the three cellulases were conducted at a range of temperatures in various binary mixtures of the ionic liquid 1-ethyl-3-methyl-imidazolium acetate with water. Our analysis demonstrates that the effects of ionic liquids on the enzymes vary in each individual case from local structural disturbances to loss of much of one of the enzyme's secondary structure. Enzymes with more negatively charged surfaces tend to resist destabilization by ionic liquids. Specific and unique structural changes in the enzymes are induced by the presence of ionic liquids. Disruption of the secondary structure, changes in dynamical motion, and local changes in the binding pocket are observed in less tolerant enzymes. Ionic-liquid-induced denaturation of one of the enzymes is indicated over the 500 ns timescale. In contrast, the most tolerant cellulase behaves similarly in water and in ionic-liquid-containing mixtures. Unlike the heuristic approaches that attempt to predict enzyme stability using macroscopic properties, molecular dynamics allows us to predict specific atomic-level structural and dynamical changes in an enzyme's behavior induced by ionic liquids and other mixed solvents. Using these insights, we propose specific experimentally testable hypotheses regarding the origin of activity loss for each of the systems investigated in this study. PMID:25692593

Jaeger, Vance; Burney, Patrick; Pfaendtner, Jim

2015-02-17

426

Synthesis and Characterization of Novel Dimeric Ionic Liquids by Conventional Approaches  

PubMed Central

The 1H-NMR shifts of the imidazolium protons of some novel dimeric ionic liquids were examined in various deuterated solvents. Interactions between the solvent and the imidazolium salt of butyl substituted ionic liquids were observed to give higher chemical shifts than methyl substitution. PMID:19325800

Ganesan, Kilivelu; Alias, Yatimah

2008-01-01

427

Recent developments of task-specific ionic liquids in organic synthesis  

Microsoft Academic Search

Task-specific ionic liquids (TSILs) have received increased attention over the past few years as it is possible to form any specific ionic liquid (IL) composition depending upon user's need of the desired physical, chemical, and biological properties. These fascinating materials have shown promising results in various areas such as organic synthesis, catalysis, and specially recent emerging trend of use as

A. D. Sawant; D. G. Raut; N. B. Darvatkar; M. M. Salunkhe

2011-01-01

428

Direct UV-spectroscopic measurement of selected ionic-liquid vapors  

SciTech Connect

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.

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

2010-01-01

429

Enthalpies of dissolution of ionic liquids in water-acetonitrile solutions at 298.15 K  

NASA Astrophysics Data System (ADS)

Enthalpies of dissolution of ionic liquids [C4mim]OTf, [C4mim]NTf2, and [C4mpy]NTf2 are measured in studying the thermodynamic characteristics of solvation and ion association for ionic liquids in nonaqueous and mixed solvents in acetonitrile-water of three compositions at 298.15 K. Standard enthalpies of solution are determined.

Belov, A. V.; Solov'ev, S. N.

2015-02-01

430

Shear and Extensional Rheology of Cellulose/Ionic Liquid Solutions Simon J. Haward1*  

E-print Network

1 Shear and Extensional Rheology of Cellulose/Ionic Liquid Solutions Simon J. Haward1* , Vivek-dilute solutions of cellulose in the ionic liquid 1-ethyl-3-methylimidazolium acetate (EMIAc). In steady shear flow extensional viscosities of the semi-dilute cellulose solutions in a uniaxial extensional flow that mimics

431

IONIC LIQUIDS AS SOLVENTS FOR BIOPOLYMERS: ACYLATION OF STARCH AND ZEIN PROTEIN  

Technology Transfer Automated Retrieval System (TEKTRAN)

A novel method for preparation of esters of starch and zein is described herein, involving the use of ionic liquid. The method is simple, rapid, efficient, and ionic liquid could be recycled. With this method, starch and zein acetates have been synthesized....

432

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

DOEpatents

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.

Luebke, David; Nulwala, Hunald; Tang, Chau

2014-12-09

433

Promotion of Atom Transfer Radical Polymerization and Ring-Opening Metathesis Polymerization in Ionic Liquids  

Microsoft Academic Search

In the last decade, there has been an increasing interest in using ionic liquids as solvents for chemical reactions and polymerizations. This interest is stimulated not only by their nonvolatility (green solvents) but also by their special properties, which often affect the course of a reaction or polymerization and the properties of products. Recent developments in ionic liquids as solvents

Meiran Xie; Huijing Han; Liang Ding; Jiaxin Shi

2009-01-01

434

Draft Genome Sequence of the Ionic Liquid-Tolerant Bacterium Bacillus amyloliquefaciens CMW1  

PubMed Central

Here, we report the draft genome sequence of an ionic liquid-tolerant bacterium, Bacillus amyloliquefaciens CMW1, which is newly isolated from a Japanese fermented soybean paste. The genome sequence will allow for a characterization of the molecular mechanism of its ionic liquid tolerance. PMID:25323721

Hirose, Yuu; Misawa, Naomi; Hurunaka, Kohei; Kishimoto, Noriaki

2014-01-01

435

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

DOEpatents

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 %.

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

2014-08-19

436

Direct Capture of Organic Acids From Fermentation Media Using Ionic Liquids  

Microsoft Academic Search

Several ionic liquids have been investigated for the extraction of organic acids from fermentation broth. Partitioning of representative organic acids (lactic, acetic, and succinic) between aqueous solution and nine hydrophobic ionic liquids was measured. The extraction efficiencies were strongly dependent on pH of the aqueous phase. Distribution coefficient was very good (approximately 60) at low succinic acid concentrations for one

K. Thomas Klasson; Whitney B. Ridenour; Brian H. Davison; Joanna McFarlane

2004-01-01

437

Structured fiber supports for ionic liquid-phase catalysis used in gas-phase continuous hydrogenation  

Microsoft Academic Search

Structured supported ionic liquid-phase (SSILP) catalysis is a new concept with the advantages of ionic liquids (ILs) used as solvents for homogeneous catalyst and the further benefits of structured heterogeneous catalysts. This is achieved by confining the IL with the transition metal complex to the surface of a structured support consisting of sintered metal fibers (SMFs). In an attempt to

Marina Ruta; Igor Yuranov; Paul J. Dyson; Gabor Laurenczy; Lioubov Kiwi-Minsker

2007-01-01

438

Viscosity Measurements on Ionic Liquids: A Cautionary Tale  

NASA Astrophysics Data System (ADS)

The vibrating-wire viscometer has proven to be an exceedingly effective means of determining the viscosity of liquids over a wide range of temperature and pressure. The instrument has a long history but a variety of technological and theoretical developments over a number of years have improved its precision and most recently have enabled absolute measurements of high accuracy. However, the nature of the electrical measurements required for the technique has inhibited its widespread use for electrically conducting liquids so that there have been only a limited number of measurements. In the particular context of ionic liquids, which have themselves attracted considerable attention, this is unfortunate because it has meant that one primary measurement technique has seldom been employed for studies of their viscosity. In the last 2 years systematic efforts have been made to explore the applicability of the vibrating-wire technique by examining a number of liquids of increasing electrical conductivity. These extensions have been successful. However, in the process we have had cause to review previous studies of the viscosity and density of the same liquids at moderate temperatures and pressures and significant evidence has been accumulated to cause concern about the application of a range of viscometric techniques to these particular fluids. Because the situation is reminiscent of that encountered for a new set of environmentally friendly refrigerants at the end of the last decade, in this paper the experimental methods employed with these liquids have been reviewed which leads to recommendations for the handling of these materials that may have consequences beyond viscometric measurements. In the process new viscosity and density data for 1-hexyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide [mim][], 1-ethyl-3-methylimidazolium ethyl sulfate [mim][], and 1-ethyl-3-methylpyridinium ethyl sulfate [mpy][] have been obtained.

Diogo, João C. F.; Caetano, Fernando J. P.; Fareleira, João M. N. A.; Wakeham, William A.

2014-10-01

439

Ionic-liquid materials for the electrochemical challenges of the future  

NASA Astrophysics Data System (ADS)

Ionic liquids are room-temperature molten salts, composed mostly of organic ions that may undergo almost unlimited structural variations. This review covers the newest aspects of ionic liquids in applications where their ion conductivity is exploited; as electrochemical solvents for metal/semiconductor electrodeposition, and as batteries and fuel cells where conventional media, organic solvents (in batteries) or water (in polymer-electrolyte-membrane fuel cells), fail. Biology and biomimetic processes in ionic liquids are also discussed. In these decidedly different materials, some enzymes show activity that is not exhibited in more traditional systems, creating huge potential for bioinspired catalysis and biofuel cells. Our goal in this review is to survey the recent key developments and issues within ionic-liquid research in these areas. As well as informing materials scientists, we hope to generate interest in the wider community and encourage others to make use of ionic liquids in tackling scientific challenges.

Armand, Michel; Endres, Frank; Macfarlane, Douglas R.; Ohno, Hiroyuki; Scrosati, Bruno

2009-08-01

440

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

PubMed Central

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

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

2013-01-01

441

A classical density functional theory for interfacial layering of ionic liquids  

SciTech Connect

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.

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

442

Ionic liquid based electrolytes for sodium-ion batteries: Na+ solvation and ionic conductivity  

NASA Astrophysics Data System (ADS)

Ionic liquid (IL) based sodium-ion (Na+) battery electrolytes obtained by mixing imidazolium-TFSI ILs (EMIm-TFSI and BMIm-TFSI) with the corresponding sodium salt (NaTFSI) have been investigated using a wide range of characterization techniques: dielectric spectroscopy, differential scanning calorimetry, densitometry, viscometry, and Raman spectroscopy. The sodium ion conducting electrolytes exhibit excellent ionic conductivities, up to 5.5 mS cm-1 at room temperature, and a useful thermal window of -86 °C to 150 °C. In more detail, Raman data analysis supported by DFT calculations on Na+-TFSI complexes, allow us to determine the sodium ion solvation and charge carrier nature as a function of salt concentration. The results are compared to data for the corresponding Li systems and while such electrolytes essentially form [Li(TFSI)2]- as the main Li+ carrier, the sodium systems seem to dominantly form [Na(TFSI)3]2- complexes. The effects on conductivity and viscosity and the consequences for sodium-ion battery implementation are discussed.

Monti, Damien; Jónsson, Erlendur; Palacín, M. Rosa; Johansson, Patrik

2014-01-01

443

Ionic Liquids: Radiation Chemistry, Solvation Dynamics and Reactivity Patterns  

SciTech Connect

Ionic liquids (ILs) are a rapidly expanding family of condensed-phase media with important applications in energy production, nuclear fuel and waste processing, improving the efficiency and safety of industrial chemical processes, and pollution prevention. ILs generally have low volatilities and are combustion-resistant, highly conductive, recyclable and capable of dissolving a wide variety of materials. They are finding new uses in chemical synthesis, catalysis, separations chemistry, electrochemistry and other areas. Ionic liquids have dramatically different properties compared to conventional molecular solvents, and they provide a new and unusual environment to test our theoretical understanding of primary radiation chemistry, charge transfer and other reactions. We are interested in how IL properties influence physical and dynamical processes that determine the stability and lifetimes of reactive intermediates and thereby affect the courses of reactions and product distributions. We study these issues by characterization of primary radiolysis products and measurements of their yields and reactivity, quantification of electron solvation dynamics and scavenging of electrons in different states of solvation. From this knowledge we wish to learn how to predict radiolytic mechanisms and control them or mitigate their effects on the properties of materials used in nuclear fuel processing, for example, and to apply IL radiation chemistry to answer questions about general chemical reactivity in ionic liquids that will aid in the development of applications listed above. Very early in our radiolysis studies it became evident that the slow solvation dynamics of the excess electron in ILs (which vary over a wide viscosity range) increase the importance of pre-solvated electron reactivity and consequently alter product distributions and subsequent chemistry. This difference from conventional solvents has profound effects on predicting and controlling radiolytic yields, which need to be quantified for the successful use under radiolytic conditions. Electron solvation dynamics in ILs are measured directly when possible and estimated using proxies (e.g. coumarin-153 dynamic emission Stokes shifts or benzophenone anion solvation) in other cases. Electron reactivity is measured using ultrafast kinetics techniques for comparison with the solvation process.

Wishart, J.F.

2011-06-12

444

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

PubMed

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

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

2015-01-01

445

Ionic Clusters vs. Shear Viscosity in Aqueous Amino Acid Ionic Liquids  

E-print Network

Aqueous solutions of amino acid ionic liquids (AAILs) are of high importance for applications in protein synthesis and solubilization, enzymatic reactions, templates for synthetic study, etc. This work employs molecular dynamics simulations using our own force field to investigate shear viscosity and cluster compositions of three 1-ethyl-3-methylimidazolium (emim) amino acid salts: [emim][ala], [emim][met], and [emim][trp] solutions (2, 5, 10, 20, 30 mol%) in water at 310 K. We, for the first time, establish simple correlations between cluster composition, on one side, and viscosity, on another side. We argue that knowledge about any of these properties alone is enough to derive insights regarding the missed properties, using the reported correlations. The numerical observations and qualitative correlations are discussed in the context of chemical structure of the amino acid anions, [ala], [met], and [trp]. The reported results will enhance progress in the efficient design and applications of AAILs and their ...

Chaban, Vitaly V

2014-01-01

446

Ionic Clusters vs Shear Viscosity in Aqueous Amino Acid Ionic Liquids.  

PubMed

Aqueous solutions of amino acid ionic liquids (AAILs) are of high importance for applications in protein synthesis and solubilization, enzymatic reactions, templates for synthetic study, etc. This work employs molecular dynamics simulations using our own force field to investigate shear viscosity and cluster compositions of three 1-ethyl-3-methylimidazolium (emim) amino acid salts: [emim][ala], [emim][met], and [emim][trp] solutions (2, 5, 10, 20, and 30 mol %) in water at 310 K. We, for the first time, establish simple correlations between cluster composition, on one side, and viscosity, on another side. We argue that knowledge about any of these properties alone is enough to derive insights regarding the missed properties, using the reported correlations. The numerical observations and qualitative correlations are discussed in the context of the chemical structure of the amino acid anions, [ala], [met], and [trp]. The reported results will enhance progress in the efficient design and applications of AAILs and their solutions. PMID:25686379

Chaban, Vitaly V; Fileti, Eudes Eterno

2015-03-01

447

Contracting cardiomyocytes in hydrophobic room-temperature ionic liquid  

SciTech Connect

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.

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

448

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

Microsoft Academic Search

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

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

2004-01-01

449

Ion Transport in Polymerized Ionic Liquid Block and Random Copolymers  

NASA Astrophysics Data System (ADS)

Polymerized ionic liquid (PIL) block copolymers, a new type of solid-state polymer electrolyte, are of interest for energy conversion and storage devices, such as fuel cells, batteries, supercapacitors, and solar cells. In this study, a series of PIL diblock and random copolymers with various PIL compositions were synthesized. These consisted of an IL monomer and a non-ionic monomer, 1-[(2-methacryloyloxy)ethyl]-3-butylimidazolium bis(trifluoromethanesulfonyl)imide (MEBIm-TFSI) and methyl methacrylate (MMA), and 1-[(2-acryloyloxy)ethyl]-3-butylimidazolium bis(trifluoromethanesulfonyl)imide (AEBIm-TFSI) and styrene (S), respectively, were synthesized. The anion conductivity (ion transport) and morphology were measured in all of the polymers with EIS, SAXS/WAXS, and TEM. Ion transport in block copolymers are significantly higher than random copolymers at the same PIL composition and are highly dependent on the block copolymer nanostructure. The relationship between ion transport mechanisms and the phase behavior of these materials will be discussed.

Elabd, Yossef; Ye, Yuesheng; Choi, Jae-Hong; Winey, Karen

2012-02-01

450

Stimuli-responsive block copolymers in ionic liquids  

NASA Astrophysics Data System (ADS)

Ionic liquids (ILs) are room temperature molten salts and have attracted much attention because of their unique properties. The characteristics of ILs (non-volatility, non-flammability, chemical stability, high ionic conductivity) can contribute to high performance energy-conversion materials. On the other hand, some polymers greatly change their solubility in ILs in response to external stimuli such as temperature and light. We have found that poly(N-isopropylacrylamide) (PNIPAm) and poly(benzyl methacrylate) (PBnMA) show upper critical solution temperature (UCST)-type phase behavior and lower critical solution temperature (LCST)-type phase behavior in an ILs, respectively. Most recently, we also discovered that certain polymers change their solubility induced by photo stimuli. In this study, we describe temperature and photo stimuli responsive self-assembly of AB type block copolymers having at least one stimuli-responsive segment in IL solution. Based on the results, we will aply to construct stimuli-responsive physical gels by using ABA tribock copolymer self assembly in an IL.

Ueki, Takeshi; Watanabe, Masayoshi; Lodge, Tim

2008-03-01

451

Ion transport and softening in a polymerized ionic liquid.  

PubMed

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

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

452

Saturation properties of 1-alkyl-3-methylimidazolium based ionic liquids.  

PubMed

We study the liquid-vapor saturation properties of room temperature ionic liquids (RTILs) belonging to the homologous series 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([Cnmim][NTf2]) using Monte Carlo simulation. We examine the effect of temperature and cation alkyl chain length n on the saturated densities, vapor pressures, and enthalpies of vaporization. These properties are explicitly calculated for temperatures spanning from 280 to 1000 K for RTILs with n = 2, 4, 6, 8, 10, and 12. We also explore how the identity of the anion influences saturation properties. Specifically, we compare results for [C(4)mim][NTf2] with those for 1-butyl-3-methylimidazolium tetrafluoroborate ([C(4)mim][BF4]) and 1-butyl-3-methylimidazolium hexafluorophosphate ([C(4)mim][PF6]). Simulations are completed with a recently developed realistic united-atom force field. A combination of direct grand canonical and isothermal-isobaric temperature expanded ensemble simulations are used to construct phase diagrams. Our results are compared with experimental data and Gibbs ensemble simulation data. Overall, we find good agreement between our results and those measured experimentally. We find that the vapor pressures and enthalpies of vaporization show a strong dependence on the size of the alkyl chain at low temperatures, whereas no particular trend is observed at high temperatures. Finally, we also discuss the effect of temperature on liquid phase nanodomains observed in RTILs with large hydrophobic groups. We do not observe a drastic change in liquid phase structure upon variation of the temperature, which suggests there is not a sharp phase transition between a nanostructured and homogeneous liquid, as has been suggested in earlier studies. PMID:24986360

Rane, Kaustubh S; Errington, Jeff