High pressure study of molecular dynamics of protic ionic liquid lidocaine hydrochloride.

PubMed

Swiety-Pospiech, A; Wojnarowska, Z; Pionteck, J; Pawlus, S; Grzybowski, A; Hensel-Bielowka, S; Grzybowska, K; Szulc, A; Paluch, M

2012-06-14

In this paper, we investigate the effect of pressure on the molecular dynamics of protic ionic liquid lidocaine hydrochloride, a commonly used pharmaceutical, by means of dielectric spectroscopy and pressure-temperature-volume methods. We observed that near T(g) the pressure dependence of conductivity relaxation times reveals a peculiar behavior, which can be treated as a manifestation of decoupling between ion migration and structural relaxation times. Moreover, we discuss the validity of thermodynamic scaling in lidocaine HCl. We also employed the temperature-volume Avramov model to determine the value of pressure coefficient of glass transition temperature, dT(g)/dP|(P = 0.1). Finally, we investigate the role of thermal and density fluctuations in controlling of molecular dynamics of the examined compound.

Structure and Dynamics of Hydroxyl-Functionalized Protic Ammonium Carboxylate Ionic Liquids.

PubMed

Thummuru, Dhileep Nagi Reddy; Mallik, Bhabani S

2017-10-26

We performed classical molecular dynamics simulations to investigate the structure and dynamics of protic ionic liquids, 2-hydroxy ethylammonium acetate, ethylammonium hydroxyacetate, and 2-hydroxyethylammonium hydroxyacetate at ambient conditions. Structural properties such as density, radial distribution functions, spatial distribution functions, and structure factors have been calculated. Dynamic properties such as mean square displacements, as well as residence and hydrogen bond dynamics have also been calculated. Hydrogen bond lifetimes and residence times change with the addition of hydroxyl groups. We observe that when a hydroxyl group is present on the cation, dynamics become very slow and it forms a strong hydrogen bond with carboxylate oxygen atoms of the anion. The hydroxyl functionalized ILs show more dynamic diversity than structurally similar ILs.

Elucidation of ionic interactions in the protic ionic liquid solutions by isothermal titration calorimetry.

PubMed

Rai, Gitanjali; Kumar, Anil

2014-04-17

The strong hydrogen-bonded network noted in protic ionic liquids (PILs) may lead to stronger interactions of the ionic entities of PILs with solvents (water, methanol, ethylene glycol, dimethylsulfoxide (DMSO), N,N'-dimethylformamide (DMF)) as compared with those of aprotic ionic liquids (APILs). The PILs used in this work are 1-methylimidazolium tetrafluoroborate, 2-methylpyridinium tetrafluoroborate, and N-methylpyrrolodinium tetrafluoroborate in comparison to 1-butyl-3-methylimidazolium tetrafluoroborate, which is classified as an APIL. In this work, the excess partial molar enthalpy, H(E)IL obtained from isothermal calorimetric titrations at 298.15 K is used to probe the nature of interactions of the PIL cations with solvent molecules against those present in APIL-solvent systems. This work also reports interesting flip-flopping in the thermal behavior of these PIL-solvent systems depending upon the structure of the cationic ring of a PIL. In some cases, these flip-flops are the specific fingerprints for specific PILs in a common solvent environment. The excess partial molar enthalpy at infinite dilution, H(E,∞)IL, of these PILs bears a critical dependence on the solvent properties. An analysis of relative apparent molar enthalpies, ϕL, of the PIL solutions by the ion interaction model of Pitzer yields important information on ionic interactions of these systems.

Structure and thermal properties of salicylate-based-protic ionic liquids as new heat storage media. COSMO-RS structure characterization and modeling of heat capacities.

PubMed

Jacquemin, Johan; Feder-Kubis, Joanna; Zorębski, Michał; Grzybowska, Katarzyna; Chorążewski, Mirosław; Hensel-Bielówka, Stella; Zorębski, Edward; Paluch, Marian; Dzida, Marzena

2014-02-28

During this research, we present a study on the thermal properties, such as the melting, cold crystallization, and glass transition temperatures as well as heat capacities from 293.15 K to 323.15 K of nine in-house synthesized protic ionic liquids based on the 3-(alkoxymethyl)-1H-imidazol-3-ium salicylate ([H-Im-C1OC(n)][Sal]) with n = 3-11. The 3D structures, surface charge distributions and COSMO volumes of all investigated ions are obtained by combining DFT calculations and the COSMO-RS methodology. The heat capacity data sets as a function of temperature of the 3-(alkoxymethyl)-1H-imidazol-3-ium salicylate are then predicted using the methodology originally proposed in the case of ionic liquids by Ge et al. 3-(Alkoxymethyl)-1H-imidazol-3-ium salicylate based ionic liquids present specific heat capacities higher in many cases than other ionic liquids that make them suitable as heat storage media and in heat transfer processes. It was found experimentally that the heat capacity increases linearly with increasing alkyl chain length of the alkoxymethyl group of 3-(alkoxymethyl)-1H-imidazol-3-ium salicylate as was expected and predicted using the Ge et al. method with an overall relative absolute deviation close to 3.2% for temperatures up to 323.15 K.

Lyotropic liquid crystalline phase behaviour in amphiphile-protic ionic liquid systems.

PubMed

Chen, Zhengfei; Greaves, Tamar L; Fong, Celesta; Caruso, Rachel A; Drummond, Calum J

2012-03-21

Approximate partial phase diagrams for nine amphiphile-protic ionic liquid (PIL) systems have been determined by synchrotron source small angle X-ray scattering, differential scanning calorimetry and cross polarised optical microscopy. The binary phase diagrams of some common cationic (hexadecyltrimethyl ammonium chloride, CTAC, and hexadecylpyridinium bromide, HDPB) and nonionic (polyoxyethylene (10) oleyl ether, Brij 97, and Pluronic block copolymer, P123) amphiphiles with the PILs, ethylammonium nitrate (EAN), ethanolammonium nitrate (EOAN) and diethanolammonium formate (DEOAF), have been studied. The phase diagrams were constructed for concentrations from 10 wt% to 80 wt% amphiphile, in the temperature range 25 °C to >100 °C. Lyotropic liquid crystalline phases (hexagonal, cubic and lamellar) were formed at high surfactant concentrations (typically >50 wt%), whereas at <40 wt%, only micelles or polydisperse crystals were present. With the exception of Brij 97, the thermal stability of the phases formed by these surfactants persisted to temperatures above 100 °C. The phase behaviour of amphiphile-PIL systems was interpreted by considering the PIL cohesive energy, liquid nanoscale order, polarity and ionicity. For comparison the phase behaviour of the four amphiphiles was also studied in water.

Effect of pressure on decoupling of ionic conductivity from structural relaxation in hydrated protic ionic liquid, lidocaine HCl.

PubMed

Swiety-Pospiech, A; Wojnarowska, Z; Hensel-Bielowka, S; Pionteck, J; Paluch, M

2013-05-28

Broadband dielectric spectroscopy and pressure-temperature-volume methods are employed to investigate the effect of hydrostatic pressure on the conductivity relaxation time (τσ), both in the supercooled and glassy states of protic ionic liquid lidocaine hydrochloride monohydrate. Due to the decoupling between the ion conductivity and structural dynamics, the characteristic change in behavior of τσ(T) dependence, i.e., from Vogel-Fulcher-Tammann-like to Arrhenius-like behavior, is observed. This crossover is a manifestation of the liquid-glass transition of lidocaine HCl. The similar pattern of behavior was also found for pressure dependent isothermal measurements. However, in this case the transition from one simple volume activated law to another was noticed. Additionally, by analyzing the changes of conductivity relaxation times during isothermal densification of the sample, it was found that compression enhances the decoupling of electrical conductivity from the structural relaxation. Herein, we propose a new parameter, dlogRτ∕dP, to quantify the pressure sensitivity of the decoupling phenomenon. Finally, the temperature and volume dependence of τσ is discussed in terms of thermodynamic scaling concept.

Lipase Immobilization on Silica Xerogel Treated with Protic Ionic Liquid and its Application in Biodiesel Production from Different Oils.

PubMed

Carvalho, Nayára B; Vidal, Bruna T; Barbosa, Anderson S; Pereira, Matheus M; Mattedi, Silvana; Freitas, Lisiane Dos S; Lima, Álvaro S; Soares, Cleide M F

2018-06-21

Treated silica xerogel with protic ionic liquid (PIL) and bifunctional agents (glutaraldehyde and epichlorohydrin) is a novel support strategy used in the effective immobilization of lipase from Burkholderia cepacia (LBC) by covalent binding. As biocatalysts with the highest activity recovery yields, LBC immobilized by covalent binding with epichlorohydrin without (203%) and with PIL (250%), was assessed by the following the hydrolysis reaction of olive oil and characterized biochemically (Michaelis⁻Menten constant, optimum pH and temperature, and operational stability). Further, the potential transesterification activity for three substrates: sunflower, soybean, and colza oils, was also determined, achieving a conversion of ethyl esters between 70 and 98%. The supports and the immobilized lipase systems were characterized using Fourier transform infrared spectra (FTIR), scanning electron microscopy (SEM), elemental analysis, and thermogravimetric (TG) analysis.

Nanostructured protic ionic liquids retain nanoscale features in aqueous solution while precursor Brønsted acids and bases exhibit different behavior.

PubMed

Greaves, Tamar L; Kennedy, Danielle F; Weerawardena, Asoka; Tse, Nicholas M K; Kirby, Nigel; Drummond, Calum J

2011-03-10

Small- and wide-angle X-ray scattering (SWAXS) has been used to investigate the effect that water has on the nanoscale structure of protic ionic liquids (PILs) along with their precursor Brønsted acids and bases. The series of PILs consisted of primary, secondary, and tertiary alkylammonium cations in conjunction with formate, nitrate, or glycolate anions. Significant differences were observed for these systems. The nanoscale aggregates present in neat protic ionic liquids were shown to be stable in size on dilution to high concentrations of water, indicating that the water is localized in the ionic region and has little effect on the nonpolar domains. The Brønsted acid-water solutions did not display nanostructure at any water concentration. Primary amine Brønsted bases formed aggregates in water, which generally displayed characteristics of poorly structured microemulsions or a form of bicontinuous phase. Exceptions were butyl- and pentylamine with high water concentrations, for which the SWAXS patterns fitted well to the Teubner-Strey model for microemulsions. Brønsted base amines containing multiple alkyl chains or hydroxyl groups did not display nanostructure at any water concentration. IR spectroscopy was used to investigate the nature of water in the various solutions. For low PIL concentrations, the water was predominately present as bulk water for PIL molar fractions less than 0.4-0.5. At high PIL concentrations, in addition to the bulk water, there was a significant proportion of perturbed water, which is water influenced in some way by the cations and anions. The molecular state of the water in the studied amines was predominately present as bulk water, with smaller contributions from perturbed water than was seen in the PILs. © 2011 American Chemical Society

A general strategy for the experimental study of the thermochemistry of protic ionic liquids: enthalpy of formation and vaporisation of 1-methylimidazolium ethanoate.

PubMed

Vitorino, Joana; Bernardes, Carlos E S; Minas da Piedade, Manuel E

2012-04-07

A general strategy to determine enthalpies of formation of protic ionic liquids, based solely on enthalpy of solution measurements, was conceived and tested for 1-methylimidazolium ethanoate, leading to Δ(f)H°(m){[Hmim][O(2)CCH(3)], 1} = -(425.7 ± 1.2) kJ mol(-1). This result in conjunction with the enthalpy of formation of gaseous 1-methylimidazole (mim) proposed in this work, Δ(f)H°(m)(mim, g) = 126.5 ± 1.1 kJ mol(-1), and Δ(f)H°(m)(CH(3)COOH, g) taken from the literature, allowed the calculation of the enthalpy of the vaporisation process [Hmim][O(2)CCH(3)](l) → mim(g) + CH(3)COOH(g) as Δ(vap)H°(m){[Hmim][O(2)CCH(3)]} = 119.4 ± 3.0 kJ mol(-1). The agreement between this value and Δ(vap)H°(m){[Hmim][O(2)CCH(3)]} = 117.3 ± 0.5 kJ mol(-1), obtained for the direct vaporisation of [Hmim][O(2)CCH(3)], by Calvet-drop microcalorimetry, gives a good indication that, as previously suggested by Fourier transform ion cyclotron resonance mass spectrometry, Raman spectroscopy, and GC-MS experiments, the vaporisation of [Hmim][O(2)CCH(3)] essentially involves a proton transfer mechanism with formation of the two volatile neutral precursor molecules (mim and CH(3)COOH). Although being a low ionicity protic ionic liquid, [Hmim][O(2)CCH(3)] was chosen to validate the methodology proposed here, since its vaporisation mechanism has been unequivocally demonstrated by different methods and for different pressure ranges.

Ionic Liquids in Lithium-Ion Batteries.

PubMed

Balducci, Andrea

2017-04-01

Lithium-ion batteries are among the most widespread energy storage devices in our society. In order to introduce these devices in new key applications such as transportation, however, their safety and their operative temperature range need to be significantly improved. These improvements can be obtained only by developing new electrolytes. Ionic liquids are presently considered among the most attractive electrolytes for the development of advanced and safer lithium-ion batteries. In this manuscript, the use of various types of ionic liquids, e.g. aprotic and protic, in lithium-ion batteries is considered. The advantages and the limits associated to the use of these innovative electrolytes are critically analysed.

Oxidative desulfurization of model diesel via dual activation by a protic ionic liquid.

PubMed

Lü, Hongying; Wang, Shunan; Deng, Changliang; Ren, Wanzhong; Guo, Baocun

2014-08-30

A novel and green carboxylate-anion-based protic ionic liquid (PIL), [Hnmp]HCOO, was prepared through a simple and atom economic neutralization reaction between N-methyl-2-pyrrolidonium (NMP) and formic acids. Both FT-IR spectra and (1)H NMR confirmed its simple salt structure. [Hnmp]HCOO exhibited so high catalytic activity that the dibenzothiophene (DBT) removal reached 99% at 50°C in 3h under conditions of VPIL/Vmodel oil=1:10 and H2O2/DBT (O/S, molar ratio)=5. The catalytic oxidation reactivity of S-compounds was found to be in the order of DBT>4,6-dimethyldibenzothiophene (4,6-DMDBT)>benzothiophene (BT). The investigation on mechanism showed that oxidative desulfurization was realized through dual activation of PIL. Moreover, [Hnmp]HCOO can be recycled for five times with an unnoticeable decrease in desulfurization activity. Copyright © 2014 Elsevier B.V. All rights reserved.

Protic ionic liquid modified electrocatalyst enables robust anode under cell reversal condition

NASA Astrophysics Data System (ADS)

Zhu, Zhengyu; Yan, Xiaocong; Tang, Haolin; Cai, Haopeng; Pan, Mu; Zhang, Haining; Luo, Jiangshui

2017-05-01

Pt/C has been commercially used as anode electrocatalyst for fuel cells but generally exhibits limited durability under conditions of fuel starvation and subsequent cell reversal. Herein we report an improved scaffold concept to simultaneously stabilize the catalyst against particle growth and reduce the adverse effects of cell reversal by modifying Pt/C with suitable protic ionic liquids (PILs). The modified Pt/C catalysts show enhanced cell reversal tolerance because of their high activity towards oxygen evolution reaction (OER), up to 300 mV lower overpotential compared to the unmodified Pt/C. Moreover, the PIL modified catalysts show better resistance to the loss of electrochemical surface area (ECSA) under simulated cell reversal conditions. The results indicate that modification of Pt/C catalysts with PILs is a promising strategy to enhance the stability and durability of electrocatalysts in fuel cell applications with the risk of frequent fuel starvation events, such as automotive fuel cells.

Tertiary and Quaternary Ammonium-Phosphate Ionic Liquids as Lubricant Additives

DOE PAGES

Barnhill, William C.; Luo, Huimin; Meyer, III, Harry M; ...

2016-06-23

In this work we investigated the feasibility of five quaternary (aprotic) and four tertiary (protic) ammonium ionic liquids (ILs) with an identical organophosphate anion as lubricant antiwear additives. Viscosity, oil solubility, thermal stability, and corrosivity of the candidate ILs were characterized and correlated to the molecular structure. The protic group exhibits higher oil solubility than the aprotic group, and longer alkyl chains seem to provide better oil solubility and higher thermal stability. Selected ILs were applied as oil additives in steel-cast iron tribological tests and demonstrated promising anti-scuffing and anti-wear functionality. The thickness, nanostructure, coverage and composition of the tribofilmmore » formed by the besting performing IL were revealed by surface characterization for mechanistic understanding of the tribochemical interactions between the IL and metal surface. Results provide fundamental insights of the correlations among the molecular structure, physiochemical properties and lubricating performance for ammonium-phosphate ILs.« less

Tertiary and Quaternary Ammonium-Phosphate Ionic Liquids as Lubricant Additives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barnhill, William C.; Luo, Huimin; Meyer, III, Harry M

In this work we investigated the feasibility of five quaternary (aprotic) and four tertiary (protic) ammonium ionic liquids (ILs) with an identical organophosphate anion as lubricant antiwear additives. Viscosity, oil solubility, thermal stability, and corrosivity of the candidate ILs were characterized and correlated to the molecular structure. The protic group exhibits higher oil solubility than the aprotic group, and longer alkyl chains seem to provide better oil solubility and higher thermal stability. Selected ILs were applied as oil additives in steel-cast iron tribological tests and demonstrated promising anti-scuffing and anti-wear functionality. The thickness, nanostructure, coverage and composition of the tribofilmmore » formed by the besting performing IL were revealed by surface characterization for mechanistic understanding of the tribochemical interactions between the IL and metal surface. Results provide fundamental insights of the correlations among the molecular structure, physiochemical properties and lubricating performance for ammonium-phosphate ILs.« less

Fuel Cell Using the Protic Ionic Liquid and Rotator Phase Solid Electrolyte Principles

DTIC Science & Technology

2008-07-15

appropriate host for the ionic liquid. (a) Papers published in peer-reviewed journals (N/A for none) [1] Thompson J, Dunn P, Holmes L, Belieres J-P...Names of Post Doctorates PERCENT_SUPPORTEDNAME Jean-Philippe Belieres 0.50 Xiaoguang Sun 0.50 1.00FTE Equivalent: 2Total Number: Names of Faculty...chemical shift for transferred protons (co-worker Jean-Philippe Belieres ) This is a fundamental study of the chemical state of the proton on the cation

Fuel Cells Using the Protic Ionic Liquid and Rotator Phase Solid Electrolyte Principles

DTIC Science & Technology

2008-02-13

Talk “High temperature Polymer Electrolyte Membrane Fuel Cells (HT- PEMFCs ) for Portable Power in Large-Scale Energy Storage Devices”, Paper Number 195...Membrane Fuel Cells (HT- PEMFCs ) for Portable Power in Large-Scale Energy Storage Devices”, Paper Number 195, 212th Meeting of the Electrochemical

Protic ionic liquids based on the dimeric and oligomeric anions: [(AcO)xH(x-1)]-.

PubMed

Johansson, K M; Izgorodina, E I; Forsyth, M; MacFarlane, D R; Seddon, K R

2008-05-28

We describe a fluidity and conductivity study as a function of composition in N-methylpyrrolidine-acetic acid mixtures. The simple 1 : 1 acid-base mixture appears to form an ionic liquid, but its degree of ionicity is quite low and such liquids are better thought of as poorly dissociated mixtures of acid and base. The composition consisting of 3 moles acetic acid and 1 mole N-methylpyrrolidine is shown to form the highest ionicity mixture in this binary due to the presence of oligomeric anionic species [(AcO)(x)H(x-1)](-) stabilised by hydrogen bonds. These oligomeric species, being weaker bases than the acetate anion, shift the proton transfer equilibrium towards formation of ionic species, thus generating a higher degree of ionicity than is present at the 1 : 1 composition. A Walden plot analysis, thermogravimetric behaviour and proton NMR data, as well as ab initio calculations of the oligomeric species, all support this conclusion.

Vaporization of protic ionic liquids derived from organic superbases and short carboxylic acids.

PubMed

Ribeiro, Filipe M S; Lima, Carlos F R A C; Vaz, Inês C M; Rodrigues, Ana S M C; Sapei, Erlin; Melo, André; Silva, Artur M S; Santos, Luís M N B F

2017-06-28

This work presents a comprehensive evaluation of the phase behaviour and cohesive enthalpy of protic ionic liquids (PILs) composed of 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) or 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) organic superbases with short-chain length (acetic, propionic and butyric) carboxylic acids. Glass transition temperatures, T g , and enthalpies of vaporization, ΔH vap , were measured for six [BH][A] (1 : 1) PILs (B = DBN, DBU; A = MeCOO, EtCOO, nPrCOO), revealing more significant changes upon increasing the number of -CH 2 - groups in the base than in the acid. The magnitude of ΔH vap evidences that liquid PILs have a high proportion of ions, although the results also indicate that in DBN PILs the concentration of neutral species is not negligible. In the gas phase, these PILs exist as a distribution of ion pairs and isolated neutral species, with speciation being dependent on the temperature and pressure conditions - at high temperatures and low pressures the separated neutral species dominate. The higher T g and ΔH vap of the DBU PILs are explained by the stronger basicity of DBU (as supported by NMR and computational calculations), which increases the extent of proton exchange and the ionic character of the corresponding PILs, resulting in stronger intermolecular interactions in condensed phases.

High-throughput approach for the identification of anilinium-based ionic liquids that are suitable for electropolymerisation.

PubMed

Abdelhamid, Muhammad E; Murdoch, Timothy; Greaves, Tamar L; O'Mullane, Anthony P; Snook, Graeme A

2015-07-21

We report the synthesis of new protic ionic liquids (PILs) based on aniline derivatives and the use of high-throughput (HT) techniques to screen possible candidates. In this work, a simple HT method was applied to rapidly screen different aniline derivatives against different acids in order to identify possible combinations that produce PILs. This was followed by repeating the HT process with a Chemspeed robotic synthesis platform for more accurate results. One of the successful combinations were then chosen to be synthesised on a larger scale for further analysis. The new PILs are of interest to the fields of ionic liquids, energy storage and especially, conducting polymers as they serve as solvents, electrolytes and monomers at the same time for possible electropolymerisation (i.e. a self-contained polymer precursor).

Nanostructure of propylammonium nitrate in the presence of poly(ethylene oxide) and halide salts

NASA Astrophysics Data System (ADS)

Stefanovic, Ryan; Webber, Grant B.; Page, Alister J.

2018-05-01

Nanoscale structure of protic ionic liquids is critical to their utility as molecular electrochemical solvents since it determines the capacity to dissolve salts and polymers such as poly(ethylene oxide) (PEO). Here we use quantum chemical molecular dynamics simulations to investigate the impact of dissolved halide anions on the nanostructure of an archetypal nanostructured protic ionic liquid, propylammonium nitrate (PAN), and how this impacts the solvation of a model PEO polymer. At the molecular level, PAN is nanostructured, consisting of charged/polar and uncharged/nonpolar domains. The charged domain consists of the cation/anion charge groups, and is formed by their electrostatic interaction. This domain solvophobically excludes the propyl chains on the cation, which form a distinct, self-assembled nonpolar domain within the liquid. Our simulations demonstrate that the addition of Cl- and Br- anions to PAN disrupts the structure within the PAN charged domain due to competition between nitrate and halide anions for the ammonium charge centre. This disruption increases with halide concentration (up to 10 mol. %). However, at these concentrations, halide addition has little effect on the structure of the PAN nonpolar domain. Addition of PEO to pure PAN also disrupts the structure within the charged domain of the liquid due to hydrogen bonding between the charge groups and the terminal PEO hydroxyl groups. There is little other association between the PEO structure and the surrounding ionic liquid solvent, with strong PEO self-interaction yielding a compact, coiled polymer morphology. Halide addition results in greater association between the ionic liquid charge centres and the ethylene oxide components of the PEO structure, resulting in reduced conformational flexibility, compared to that observed in pure PAN. Similarly, PEO self-interactions increase in the presence of Cl- and Br- anions, compared to PAN, indicating that the addition of halide salts to PAN decreases its utility as a molecular solvent for polymers such as PEO.

Nonhumidified intermediate temperature fuel cells using protic ionic liquids.

PubMed

Lee, Seung-Yul; Ogawa, Atsushi; Kanno, Michihiro; Nakamoto, Hirofumi; Yasuda, Tomohiro; Watanabe, Masayoshi

2010-07-21

In this paper, the characterization of a protic ionic liquid, diethylmethylammonium trifluoromethanesulfonate ([dema][TfO]), as a proton conductor for a fuel cell and the fabrication of a membrane-type fuel cell system using [dema][TfO] under nonhumidified conditions at intermediate temperatures are described in detail. In terms of physicochemical and electrochemical properties, [dema][TfO] exhibits high activity for fuel cell electrode reactions (i.e., the hydrogen oxidation reaction (HOR) and oxygen reduction reaction (ORR)) at a Pt electrode, and the open circuit voltage (OCV) of a liquid fuel cell is 1.03 V at 150 degrees C, as has reported in ref 27. However, diethylmethylammonium bis(trifluoromethane sulfonyl)amide ([dema][NTf(2)]) has relatively low HOR and ORR activity, and thus, the OCV is ca. 0.7 V, although [dema][NTf(2)] and [dema][TfO] have an identical cation ([dema]) and similar thermal and bulk-transport properties. Proton conduction occurs mainly via the vehicle mechanism in [dema][TfO] and the proton transference number (t(+)) is 0.5-0.6. This relatively low t(+) appears to be more disadvantageous for a proton conductor than for other electrolytes such as hydrated sulfonated polymer electrolyte membranes (t(+) = 1.0). However, fast proton-exchange reactions occur between ammonium cations and amines in a model compound. This indicates that the proton-exchange mechanism contributes to the fuel cell system under operation, where deprotonated amines are continuously generated by the cathodic reaction, and that polarization of the cell is avoided. Six-membered sulfonated polyimides in the diethylmethylammonium form exhibit excellent compatibility with [dema][TfO]. The composite membranes can be obtained up to a [dema][TfO] content of 80 wt % and exhibit good thermal stability, high ionic conductivity, and mechanical strength and gas permeation comparable to those of hydrated Nafion. H(2)/O(2) fuel cells prepared using the composite membranes can successfully operate at temperatures from 30 to 140 degrees C under nonhumidified conditions, and a current density of 250 mA cm(-2) is achieved at 120 degrees C. The protic ionic liquid and its composite membrane are a possible candidate for an electrolyte of a H(2)/O(2) fuel cell that operates under nonhumidified conditions.

(Eco)toxicity and biodegradability of protic ionic liquids.

PubMed

Oliveira, Maria V S; Vidal, Bruna T; Melo, Claudia M; de Miranda, Rita de C M; Soares, Cleide M F; Coutinho, João A P; Ventura, Sónia P M; Mattedi, Silvana; Lima, Álvaro S

2016-03-01

Ionic liquids (ILs) are often claimed to be "environmentally friendly" compounds however, the knowledge of their potential toxicity towards different organisms and trophic levels is still limited, in particular when protic ionic liquids (PILs) are addressed. This study aims to evaluate the toxicity against various microorganisms and the biodegradability of four PILs namely, N-methyl-2-hydroxyethylammonium acetate, m-2-HEAA; N-methyl-2-hydroxyethylammonium propionate, m-2-HEAPr; N-methyl-2-hydroxyethylammonium butyrate, m-2-HEAB; and N-methyl-2-hydroxyethylammonium pentanoate, m-2-HEAP. The antimicrobial activity was determined against the two bacteria, Sthaplylococcus aureus ATCC-6533 and Escherichia coli CCT-0355; the yeast Candida albicans ATCC-76645; and the fungi Fusarium sp. LM03. The toxicity of all PILs was tested against the aquatic luminescent marine bacterium Vibrio fischeri using the Microtox(®) test. The impact of the PILs was also studied regarding their effect on lettuce seeds (Lactuta sativa). The biodegradability of these PILs was evaluated using the ratio between the biochemical oxygen demand (BOD) and the chemical oxygen demand (COD). The results show that, in general, the elongation of the alkyl chain tends to increase the negative impact of the PILs towards the organisms and biological systems under study. According to these results, m-2-HEAA and m-2-HEAP are the less and most toxic PILs studied in this work, respectively. Additionally, all the PILs have demonstrated low biodegradability. Copyright © 2016. Published by Elsevier Ltd.

New membranes based on ionic liquids for PEM fuel cells at elevated temperatures

NASA Astrophysics Data System (ADS)

Ye, H.; Huang, J.; Xu, J. J.; Kodiweera, N. K. A. C.; Jayakody, J. R. P.; Greenbaum, S. G.

Proton exchange membrane (PEM) fuel cells operating at elevated temperature, above 120 °C, will yield significant benefits but face big challenges for the development of suitable PEMs. The objectives of this research are to demonstrate the feasibility of the concept and realize [acid/ionic liquid/polymer] composite gel-type membranes as such PEMs. Novel membranes consisting of anhydrous proton solvent H 3PO 4, the protic ionic liquid PMIH 2PO 4, and polybenzimidazole (PBI) as a matrix have been prepared and characterized for PEM fuel cells intended for operation at elevated temperature (120-150 °C). Physical and electrochemical analyses have demonstrated promising characteristics of these H 3PO 4/PMIH 2PO 4/PBI membranes at elevated temperature. The proton transport mechanism in these new membranes has been investigated by Fourier transform infrared and nuclear magnetic resonance spectroscopic methods.

Hydrogen bonding in a mixture of protic ionic liquids: a molecular dynamics simulation study.

PubMed

Paschek, Dietmar; Golub, Benjamin; Ludwig, Ralf

2015-04-07

We report results of molecular dynamics (MD) simulations characterising the hydrogen bonding in mixtures of two different protic ionic liquids sharing the same cation: triethylammonium-methylsulfonate (TEAMS) and triethylammonium-triflate (TEATF). The triethylammonium-cation acts as a hydrogen-bond donor, being able to donate a single hydrogen-bond. Both, the methylsulfonate- and the triflate-anions can act as hydrogen-bond acceptors, which can accept multiple hydrogen bonds via their respective SO3-groups. In addition, replacing a methyl-group in the methylsulfonate by a trifluoromethyl-group in the triflate significantly weakens the strength of a hydrogen bond from an adjacent triethylammonium cation to the oxygen-site in the SO3-group of the anion. Our MD simulations show that these subtle differences in hydrogen bond strength significantly affect the formation of differently-sized hydrogen-bonded aggregates in these mixtures as a function of the mixture-composition. Moreover, the reported hydrogen-bonded cluster sizes can be predicted and explained by a simple combinatorial lattice model, based on the approximate coordination number of the ions, and using statistical weights that mostly account for the fact that each anion can only accept three hydrogen bonds.

Particle self-assembly at ionic liquid-based interfaces.

PubMed

Frost, Denzil S; Nofen, Elizabeth M; Dai, Lenore L

2014-04-01

This review presents an overview of the nature of ionic liquid (IL)-based interfaces and self-assembled particle morphologies of IL-in-water, oil- and water-in-IL, and novel IL-in-IL Pickering emulsions with emphasis on their unique phenomena, by means of experimental and computational studies. In IL-in-water Pickering emulsions, particles formed monolayers at ionic liquid-water interfaces and were close-packed on fully covered emulsion droplets or aggregated on partially covered droplets. Interestingly, other than equilibrating at the ionic liquid-water interfaces, microparticles with certain surface chemistries were extracted into the ionic liquid phase with a high efficiency. These experimental findings were supported by potential of mean force calculations, which showed large energy drops as hydrophobic particles crossed the interface into the IL phase. In the oil- and water-in-IL Pickering emulsions, microparticles with acidic surface chemistries formed monolayer bridges between the internal phase droplets rather than residing at the oil/water-ionic liquid interfaces, a significant deviation from traditional Pickering emulsion morphology. Molecular dynamics simulations revealed aspects of the mechanism behind this bridging phenomenon, including the role of the droplet phase, surface chemistry, and inter-particle film. Novel IL-in-IL Pickering emulsions exhibited an array of self-assembled morphologies including the previously observed particle absorption and bridging phenomena. The appearance of these morphologies depended on the particle surface chemistry as well as the ILs used. The incorporation of particle self-assembly with ionic liquid science allows for new applications at the intersection of these two fields, and have the potential to be numerous due to the tunability of the ionic liquids and particles incorporated, as well as the particle morphology by combining certain groups of particle surface chemistry, IL type (protic or aprotic), and whether oil or water is incorporated. © 2013.

Hydrogen-bonding interactions and protic equilibria in room-temperature ionic liquids containing crown ethers.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marin, T.; Shkrob, I.; Dietz, M.

2011-04-14

Nuclear magnetic resonance (NMR) spectroscopy has been used to study hydrogen-bonding interactions between water, associated and dissociated acids (i.e., nitric and methanesulfonic acids), and the constituent ions of several water-immiscible room-temperature ionic liquids (ILs). In chloroform solutions also containing a crown ether (CE), water molecules strongly associate with the IL ions, and there is rapid proton exchange between these bound water molecules and hydronium associated with the CE. In neat ILs, the acids form clusters differing in their degree of association and ionization, and their interactions with the CEs are weak. The CE can either promote proton exchange between differentmore » clusters in IL solution when their association is weak or inhibit such exchange when the association is strong. Even strongly hydrophobic ILs are shown to readily extract nitric acid from aqueous solution, typically via the formation of a 1:1:1 {l_brace}H{sub 3}O{sup +} {center_dot} CE{r_brace}NO{sub 3}{sup -} complex. In contrast, the extraction of methanesulfonic acid is less extensive and proceeds mainly by IL cation-hydronium ion exchange. The relationship of these protic equilibria to the practical application of hydrophobic ILs (e.g., in spent nuclear fuel reprocessing) is discussed.« less

Double Soft-Template Synthesis of Nitrogen/Sulfur-Codoped Hierarchically Porous Carbon Materials Derived from Protic Ionic Liquid for Supercapacitor.

PubMed

Sun, Li; Zhou, Hua; Li, Li; Yao, Ying; Qu, Haonan; Zhang, Chengli; Liu, Shanhu; Zhou, Yanmei

2017-08-09

Heteroatom-doped hierarchical porous carbon materials derived from the potential precursors and prepared by a facile, effective, and low-pollution strategy have recently been particularly concerned in different research fields. In this study, the interconnected nitrogen/sulfur-codoped hierarchically porous carbon materials have been successfully obtained via one-step carbonization of the self-assembly of [Phne][HSO 4 ] (a protic ionic liquid originated from dilute sulfuric acid and phenothiazine by a straightforward acid-base neutralization) and the double soft-template of OP-10 and F-127. During carbonization process, OP-10 as macroporous template and F-127 as mesoporous template were removed, while [Phne][HSO 4 ] not only could be used as carbon, nitrogen, and sulfur source, but also as a pore forming agent to create micropores. The acquired carbon materials for supercapacitor not only hold a large specific capacitance of 302 F g -1 even at 1.0 A g -1 , but also fine rate property with 169 F g -1 at 10 A g -1 and excellent capacitance retention of nearly 100% over 5000 circulations in 6 M KOH electrolyte. Furthermore, carbon materials also present eximious rate performance with 70% in 1 M Na 2 SO 4 electrolyte.

Nanostructure-thermal conductivity relationships in protic ionic liquids.

PubMed

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

2014-10-16

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

Synthesis and characterization of low viscosity carbon dioxide binding organic liquids for flue gas clean up

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koech, Phillip K.; Malhotra, Deepika; Heldebrant, David J.

2015-01-01

Climate change is partly attributed to global anthropogenic carbon dioxide (CO2) emission to the atmosphere. These environmental effects can be mitigated by CO2 capture, utilization and storage. Alkanolamine solvents, such as monoethanolamine (MEA), which bind CO2 as carbamates or bicarbonate salts are used for CO2 capture in niche applications. These solvents consist of approximately 30 wt% of MEA in water, exhibiting a low, CO2-rich viscosity, fast kinetics and favorable thermodynamics. However, these solvents have low CO2 capacity and high heat capacity of water, resulting in prohibitively high costs of thermal solvent regeneration. Effective capture of the enormous amounts of CO2more » produced by coal-fired plants requires a material with high CO2 capacity and low regeneration energy requirements. To this end, several water-lean transformational solvents systems have been developed in order to reduce these energy penalties. These technologies include nano-material organic hybrids (NOHMs), task-specific, protic and conventional ionic liquids, phase change solvents. As part of an ongoing program in our group, we have developed new water lean transformational solvents known as CO2 binding organic liquids (CO2BOLs) which have the potential to be energy efficient CO2 capture solvents. These solvents, also known as switchable ionic liquids meaning, are organic solvents that can reversibly transform from non- ionic to ionic form and back. The zwitterionic state in these liquids is formed when low polarity non-ionic alkanolguanidines or alkanolamidines react with CO2 or SO2 to form ionic liquids with high polarity. These polar ionic liquids can be thermally converted to the less polar non-ionic solvent by releasing CO2.« less

Estudio tribologico de nuevos nanofluidos ionicos y nanomateriales

NASA Astrophysics Data System (ADS)

Saurin Serrano, Noelia

The present work has focused on tribology and surface engineering of materials and interfaces. In the first place, four new halogen-free ionic liquids have been studied as boundary lubricants in reciprocating steel-sapphire and steel-epoxy resin contacts. Two different steel surface roughness have been compared, finding not only low friction, but also non-measurable wear, in the case of higher roughness. New ionic nanofluids have been obtained by dispersion of two commercial graphene grades in the ionic liquid 1-octyl-3-methylimidazlium tetrafluoroborate, finding the best friction reducing and antiwear performance in pin-on-disc sapphire-steel and steel-epoxy resin contacts. New aqueous lubricants have been developed by addition of new dispersions of graphene in a protic ionic liquid free from contaminant elements, as it is an ammonium cation citrate anion derivative. Controlled water evaporation leads to new self-lubricating surfaces. In the present work, the tribological performance of a fragile low wear-resistance materials such as epoxy resin has been improved by addition of variables concentrations of the ionic liquid 1-octyl-3-methylimidazolium tetrafluoroborate or carbon nanophases such as singlewalled carbon nanotubes or graphene. Blended with the ionic liquid or previously modified by it. The first epoxy resin materials with ability of self-healing the abrasion surface damage, due to the addition of ionic liquid, are described. New epoxy resin matrix nanocomposites, obtained by combination of carbon nanophases and ionic liquid, show better tribological behavior than the materials containing any of the additives separately. Finally, a new research line on the cure of the new epoxy matrix nanocomoposites as protective coatings on steel substrates has been initiated.

Protic ammonium carboxylate ionic liquids: insight into structure, dynamics and thermophysical properties by alkyl group functionalization.

PubMed

Reddy, Th Dhileep N; Mallik, Bhabani S

2017-04-19

This study is aimed at characterising the structure, dynamics and thermophysical properties of five alkylammonium carboxylate ionic liquids (ILs) from classical molecular dynamics simulations. The structural features of these ILs were characterised by calculating the site-site radial distribution functions, g(r), spatial distribution functions and structure factors. The structural properties demonstrate that ILs show greater interaction between cations and anions when alkyl chain length increases on the cation or anion. In all ILs, spatial distribution functions show that the anion is close to the acidic hydrogen atoms of the ammonium cation. We determined the role of alkyl group functionalization of the charged entities, cations and anions, in the dynamical behavior and the transport coefficients of this family of ionic liquids. The dynamics of ILs are described by studying the mean square displacement (MSD) of the centres of mass of the ions, diffusion coefficients, ionic conductivities and hydrogen bonds as well as residence dynamics. The diffusion coefficients and ionic conductivity decrease with an increase in the size of the cation or anion. The effect of alkyl chain length on ionic conductivity calculated in this article is consistent with the findings of other experimental studies. Hydrogen bond lifetimes and residence times along with structure factors were also calculated, and are related to alkyl chain length.

Crystal Structure and Properties of Imidazo-Pyridine Ionic Liquids.

PubMed

Farren-Dai, Marco; Cameron, Stanley; Johnson, Michel B; Ghandi, Khashayar

2018-07-05

Computational studies were performed on novel protic ionic liquids imidazolium-[1,2-a]-pyridine trifluoroacetate [ImPr][TFA] synthesized by the reaction of imidazo-[1,2a]-pyridine (ImPr) with trifluoroacetic acid (TFA), and on fused salt imidazolium-[1,2-a]-pyridine maleamic carbonate [ImPr][Mal] synthesized by reaction of ImPr with maleamic acid (Mal). Synthesis was performed as one-pot reactions, which applies green chemistry tenets. Both these compounds begin to decompose at 180°C. Our computational studies suggest another thermal reaction channel, in which [ImPr][Mal] can also thermally polymerizes to polyacrylamide which then cyclizes. This is thermal product remains stable up to 700 degrees, consistent with our thermogravimetric studies. [ImPr][TFA] exhibited good conductivity and ideal ionic behavior, as evaluated by a Walden plot. X-ray crystallography of [ImPr][TFA] revealed a tightly packed system for the crystals as a result of strong ionic interaction, pi-stacking, and fluorine-CH interactions. Both synthesized compounds exhibited some CO 2 absorptivity, with [ImPr][Mal] outperforming [ImPr][TFA] in this regard. The quantum chemistry based computational methods can shed light on many properties of these ionic liquids, but they are challenged in fully describing their ionic nature. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Protic Salt Polymer Membranes: High-Temperature Water-Free Proton-Conducting Membranes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gervasio, Dominic Francis

2010-09-30

This research on proton-containing (protic) salts directly addresses proton conduction at high and low temperatures. This research is unique, because no water is used for proton ionization nor conduction, so the properties of water do not limit proton fuel cells. A protic salt is all that is needed to give rise to ionized proton and to support proton mobility. A protic salt forms when proton transfers from an acid to a base. Protic salts were found to have proton conductivities that are as high as or higher than the best aqueous electrolytes at ambient pressures and comparable temperatures without ormore » with water present. Proton conductivity of the protic salts occurs providing two conditions exist: i) the energy difference is about 0.8 eV between the protic-salt state versus the state in which the acid and base are separated and 2) the chemical constituents rotate freely. The physical state of these proton-conducting salts can be liquid, plastic crystal as well as solid organic and inorganic polymer membranes and their mixtures. Many acids and bases can be used to make a protic salt which allows tailoring of proton conductivity, as well as other properties that affect their use as electrolytes in fuel cells, such as, stability, adsorption on catalysts, environmental impact, etc. During this project, highly proton conducting (~ 0.1S/cm) protic salts were made that are stable under fuel-cell operating conditions and that gave highly efficient fuel cells. The high efficiency is attributed to an improved oxygen electroreduction process on Pt which was found to be virtually reversible in a number of liquid protic salts with low water activity (< 1% water). Solid flexible non-porous composite membranes, made from inorganic polymer (e.g., 10%indium 90%tin pyrophosphate, ITP) and organic polymer (e.g., polyvinyl pyridinium phosphate, PVPP), were found that give conductivity and fuel cell performances similar to phosphoric acid electrolyte with no need for hydration at ambient pressures. Synthesis and processing of these protic salts into proton-conducting membrane is far from optimized. This protic salt approach has great promise for more improvements in proton conducting membranes for making practical compact, lightweight and inexpensive fuel cells with uses ranging from small electronics (Power = 1 to 100 Watts) to transportation (kiloWatts) to stationary applications (>100 kiloWatts). This work clearly showed that proton can be conducted without water using protoic ionic liquids which are Bronsted salts which contain a proton and whose acid and base moieties have pK separated by more than 4 units and less than 14. A key finding is that the base used should be significantly different than the basicity of water or else water displaces the base and an ordinary acid membrane is left behind. This is the case where the acid moiety is sulfonic acid found on perfluorinated polymeric membranes. This PI suggests that a fruitful route for attaining highly proton-conductive stable protic salt membranes is to use the STABLE poly-phosphazene (-P=N-) polymer backbone with electrochemically STABLE pendant acid or base units on the phosphorous of poly-phosphazene and with suitable pK so the base is NOT the same pK as water. From this work this should give stable water-free proton conductors which should allow for stable fuel cells with Pt catalysts and possible with non-platinum catalyst for the hydrogen anode and oxygen cathode.« less

NEXAFS spectroscopy of ionic liquids: experiments versus calculations.

PubMed

Fogarty, Richard M; Matthews, Richard P; Clough, Matthew T; Ashworth, Claire R; Brandt-Talbot, Agnieszka; Corbett, Paul J; Palgrave, Robert G; Bourne, Richard A; Chamberlain, Thomas W; Vander Hoogerstraete, Tom; Thompson, Paul B J; Hunt, Patricia A; Besley, Nicholas A; Lovelock, Kevin R J

2017-11-29

Experimental near edge X-ray absorption fine structure (NEXAFS) spectra are reported for 12 ionic liquids (ILs) encompassing a range of chemical structures for both the sulfur 1s and nitrogen 1s edges and compared with time-dependent density functional theory (TD-DFT) calculations. The energy scales for the experimental data were carefully calibrated against literature data. Gas phase calculations were performed on lone ions, ion pairs and ion pair dimers, with a wide range of ion pair conformers considered. For the first time, it is demonstrated that TD-DFT is a suitable method for simulating NEXAFS spectra of ILs, although the number of ions included in the calculations and their conformations are important considerations. For most of the ILs studied, calculations on lone ions in the gas phase were sufficient to successfully reproduce the experimental NEXAFS spectra. However, for certain ILs - for example, those containing a protic ammonium cation - calculations on ion pairs were required to obtain a good agreement with experimental spectra. Furthermore, significant conformational dependence was observed for the protic ammonium ILs, providing insight into the predominant liquid phase cation-anion interactions. Among the 12 investigated ILs, we find that four have an excited state that is delocalised across both the cation and the anion, which has implications for any process that depends on the excited state, for example, radiolysis. Considering the collective experimental and theoretical data, we recommend that ion pairs should be the minimum number of ions used for the calculation of NEXAFS spectra of ILs.

Hydrogen bonding in protic ionic liquids: structural correlations, vibrational spectroscopy, and rotational dynamics of liquid ethylammonium nitrate

NASA Astrophysics Data System (ADS)

Zentel, Tobias; Overbeck, Viviane; Michalik, Dirk; Kühn, Oliver; Ludwig, Ralf

2018-02-01

The properties of the hydrogen bonds in ethylammonium nitrate (EAN) are analyzed by using molecular dynamics simulations and infrared as well as nuclear magnetic resonance experiments. EAN features a flexible three-dimensional network of hydrogen bonds with moderate strengths, which makes it distinct from related triethylammonium-based ionic liquids. First, the network’s flexibility is manifested in a not very pronounced correlation of the hydrogen bond geometries, which is caused by rapid interchanges of bonding partners. The large flexibility of the network also leads to a substantial broadening of the mid-IR absorption band, with the contributions due to N-H stretching motions ranging from 2800 to 3250 cm-1. Finally, the different dynamics are also seen in the rotational correlation of the N-H bond vector, where a correlation time as short as 16.1 ps is observed.

The Relation between Vaporization Enthalpies and Viscosities: Eyring's Theory Applied to Selected Ionic Liquids.

PubMed

Bonsa, Anne-Marie; Paschek, Dietmar; Zaitsau, Dzmitry H; Emel'yanenko, Vladimir N; Verevkin, Sergey P; Ludwig, Ralf

2017-05-19

Key properties for the use of ionic liquids as electrolytes in batteries are low viscosities, low vapor pressure and high vaporization enthalpies. Whereas the measurement of transport properties is well established, the determination of vaporization enthalpies of these extremely low volatile compounds is still a challenge. At a first glance both properties seem to describe different thermophysical phenomena. However, eighty years ago Eyring suggested a theory which related viscosities and vaporization enthalpies to each other. The model is based on Eyring's theory of absolute reaction rates. Recent attempts to apply Eyring's theory to ionic liquids failed. The motivation of our study is to show that Eyring's theory works, if the assumptions specific for ionic liquids are fulfilled. For that purpose we measured the viscosities of three well selected protic ionic liquids (PILs) at different temperatures. The temperature dependences of viscosities were approximated by the Vogel-Fulcher-Tamann (VFT) relation and extrapolated to the high-temperature regime up to 600 K. Then the VFT-data could be fitted to the Eyring-model. The values of vaporization enthalpies for the three selected PILs predicted by the Eyring model have been very close to the experimental values measured by well-established techniques. We conclude that the Eyring theory can be successfully applied to the chosen set of PILs, if the assumption that ionic pairs of the viscous flow in the liquid and the ionic pairs in the gas phase are similar is fulfilled. It was also noticed that proper transfer of energies can be only derived if the viscosities and the vaporization energies are known for temperatures close to the liquid-gas transition temperature. The idea to correlate easy measurable viscosities of ionic liquids with their vaporization enthalpies opens a new way for a reliable assessment of these thermodynamic properties for a broad range of ionic liquids. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Controlling Proton Delivery through Catalyst Structural Dynamics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cardenas, Allan Jay P.; Ginovska, Bojana; Kumar, Neeraj

The fastest synthetic molecular catalysts for production and oxidation of H2 emulate components of the active site of natural hydrogenases. The role of controlled structural dynamics is recognized as a critical component in the catalytic performance of many enzymes, including hydrogenases, but is largely neglected in the design of synthetic molecular cata-lysts. In this work, the impact of controlling structural dynamics on the rate of production of H2 was studied for a series of [Ni(PPh2NC6H4-R2)2]2+ catalysts including R = n-hexyl, n-decyl, n-tetradecyl, n-octadecyl, phenyl, or cyclohexyl. A strong correlation was observed between the ligand structural dynamics and the rates ofmore » electrocatalytic hydrogen production in acetonitrile, acetonitrile-water, and protic ionic liquid-water mixtures. Specifically, the turnover frequencies correlate inversely with the rates of ring inversion of the amine-containing ligand, as this dynamic process dictates the positioning of the proton relay in the second coordination sphere and therefore governs protonation at either catalytically productive or non-productive sites. This study demonstrates that the dynamic processes involved in proton delivery can be controlled through modifications of the outer coordination sphere of the catalyst, similar to the role of the protein architecture in many enzymes. The present work provides new mechanistic insight into the large rate enhancements observed in aqueous protic ionic liquid media for the [Ni(PPh2NR2)]2+ family of catalysts. The incorporation of controlled structural dynamics as a design parameter to modulate proton delivery in molecular catalysts has enabled H2 production rates that are up to three orders of magnitude faster than the [Ni(PPh2NPh2)]2+complex. The observed turnover frequencies are up to 106 s-1 in acetonitrile-water, and over 107 s-1 in protic ionic liquid-water mixtures, with a minimal increase in overpotential. This material is based upon work supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, and was performed in part using the Molecular Science Computing Facility (MSCF) in the William R. Wiley Environmental Molecular Sciences Laboratory, a DOE national scientific user facility located at Pacific Northwest National Laboratory (PNNL). PNNL is operated by Battelle for DOE.« less

Molecular dynamics simulations of the structure and single-particle dynamics of mixtures of divalent salts and ionic liquids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gómez-González, Víctor; Docampo-Álvarez, Borja; Gallego, Luis J.

2015-09-28

We report a molecular dynamics study of the structure and single-particle dynamics of mixtures of a protic (ethylammonium nitrate) and an aprotic (1-butyl-3-methylimidazolium hexaflurophosphate [BMIM][PF{sub 6}]) room-temperature ionic liquids doped with magnesium and calcium salts with a common anion at 298.15 K and 1 atm. The solvation of these divalent cations in dense ionic environments is analyzed by means of apparent molar volumes of the mixtures, radial distribution functions, and coordination numbers. For the protic mixtures, the effect of salt concentration on the network of hydrogen bonds is also considered. Moreover, single-particle dynamics of the salt cations is studied by means ofmore » their velocity autocorrelation functions and vibrational densities of states, explicitly analyzing the influence of salt concentration, and cation charge and mass on these magnitudes. The effect of the valency of the salt cation on these properties is considered comparing the results with those for the corresponding mixtures with lithium salts. We found that the main structural and dynamic features of the local solvation of divalent cations in ionic liquids are similar to those of monovalent salts, with cations being localized in the polar nanoregions of the bulk mixture coordinated in monodentate and bidentate coordination modes by the [NO{sub 3}]{sup −} and [PF{sub 6}]{sup −} anions. However, stronger electrostatic correlations of these polar nanoregions than in mixtures with salts with monovalent cations are found. The vibrational modes of the ionic liquid (IL) are seen to be scarcely affected by the addition of the salt, and the effect of mass and charge on the vibrational densities of states of the dissolved cations is reported. Cation mass is seen to exert a deeper influence than charge on the low-frequency vibrational spectra, giving a red shift of the vibrational modes and a virtual suppression of the higher energy vibrational modes for the heavier Ca{sup 2+} cations. No qualitative difference with monovalent cations was found in what solvation is concerned, which suggests that no enhanced reduction of the mobility of these cations and their complexes in ILs respective to those of monovalent cations is to be expected.« less

One-pot integrated biofuel production using low-cost biocompatible protic ionic liquids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Jian; Konda, N. V. S. N. Murthy; Parthasarathi, Ramakrishnan

The transformation of biomass into liquid fuels is of great importance. Previous work has demonstrated the capability of specific ionic liquids (ILs), such as 1-ethyl-3-methylimidazolium acetate ([C(2)C(1)Im][OAc]) and cholinium lysinate ([Ch][Lys]), to be effective biomass pretreatment solvents. Using these ILs for an integrated biomass-to-biofuel configuration is still challenging due to a significant water-wash related to the high toxicity of [C(2)C(1)Im][OAc] and pH adjustment prior to saccharification for the highly basic [Ch][Lys]. In this work, we demonstrate, for the first time, that a one-pot integrated biofuel production is enabled by a low cost (similar to$1 per kg) and biocompatible protic ILmore » (PIL), ethanolamine acetate, without pH adjustments, water-wash and solid-liquid separations. After pretreatment, the whole slurry is directly used for simultaneous saccharification and fermentation (SSF) with commercial enzyme cocktails and wild type yeast strains, generating 70% of the theoretical ethanol yield (based on switchgrass). The structure-performance relationships of PILs in terms of lignin removal, net basicity, and pH value are systematically studied. A technoeconomic analysis (TEA) revealed that an integrated biorefinery concept based on this PIL process could potentially reduce the minimum ethanol selling price by more than 40% compared to scenarios that require pH adjustment prior to SSF. Improvement of the economic performance will be made by reducing the dilution and enzyme loading during SSF as identified by TEA. This study demonstrates the impact of a biocompatible IL in terms of process optimization and conversion efficiency, and opens up avenues for realizing an IL based efficiently integrated biomass conversion technology.« less

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

NASA Astrophysics Data System (ADS)

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

2016-09-01

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

Electrode Reactions Coupled with Chemical Reactions of Oxygen, Water and Acetaldehyde in an Ionic Liquid: New Approaches for Sensing Volatile Organic Compounds.

PubMed

Chi, Xiaowei; Tang, Yongan; Zeng, Xiangqun

2016-10-20

Water and oxygen are ubiquitous present in ambient conditions. This work studies the unique oxygen, trace water and a volatile organic compound (VOC) acetaldehyde redox chemistry in a hydrophobic and aprotic ionic liquid (IL), 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ([Bmpy] [NTf 2 ]) by cyclic voltammetry and potential step methods. One electron oxygen reduction leads to superoxide radical formation in the IL. Trace water in the IL acts as a protic species that reacts with the superoxide radical. Acetaldehyde is a stronger protic species than water for reacting with the superoxide radical. The presence of trace water in the IL was also demonstrated to facilitate the electro-oxidation of acetaldehyde, with similar mechanism to that in the aqueous solutions. A multiple-step coupling reaction mechanism between water, superoxide radical and acetaldehyde has been described. The unique characteristics of redox chemistry of acetaldehyde in [Bmpy][NTf 2 ] in the presence of oxygen and trace water can be controlled by electrochemical potentials. By controlling the electrode potential windows, several methods including cyclic voltammetry, potential step methods (single-potential, double-potential and triple-potential step methods) were established for the quantification of acetaldehyde. Instead of treating water and oxygen as frustrating interferents to ILs, we found that oxygen and trace water chemistry in [Bmpy][NTf 2 ] can be utilized to develop innovative electrochemical methods for electroanalysis of acetaldehyde.

Electrode Reactions Coupled with Chemical Reactions of Oxygen, Water and Acetaldehyde in an Ionic Liquid: New Approaches for Sensing Volatile Organic Compounds

PubMed Central

Chi, Xiaowei; Tang, Yongan; Zeng, Xiangqun

2017-01-01

Water and oxygen are ubiquitous present in ambient conditions. This work studies the unique oxygen, trace water and a volatile organic compound (VOC) acetaldehyde redox chemistry in a hydrophobic and aprotic ionic liquid (IL), 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ([Bmpy] [NTf2]) by cyclic voltammetry and potential step methods. One electron oxygen reduction leads to superoxide radical formation in the IL. Trace water in the IL acts as a protic species that reacts with the superoxide radical. Acetaldehyde is a stronger protic species than water for reacting with the superoxide radical. The presence of trace water in the IL was also demonstrated to facilitate the electro-oxidation of acetaldehyde, with similar mechanism to that in the aqueous solutions. A multiple-step coupling reaction mechanism between water, superoxide radical and acetaldehyde has been described. The unique characteristics of redox chemistry of acetaldehyde in [Bmpy][NTf2] in the presence of oxygen and trace water can be controlled by electrochemical potentials. By controlling the electrode potential windows, several methods including cyclic voltammetry, potential step methods (single-potential, double-potential and triple-potential step methods) were established for the quantification of acetaldehyde. Instead of treating water and oxygen as frustrating interferents to ILs, we found that oxygen and trace water chemistry in [Bmpy][NTf2] can be utilized to develop innovative electrochemical methods for electroanalysis of acetaldehyde. PMID:29142331

The Nature of the Interactions in Triethanolammonium-Based Ionic Liquids. A Quantum Chemical Study.

PubMed

Fedorova, Irina V; Safonova, Lyubov P

2018-05-10

Structural features and interionic interactions play a crucial role in determining the overall stability of ionic liquids and their physicochemical properties. Therefore, we performed high-level quantum-chemical study of different cation-anion pairs representing the building units of protic ionic liquids based on triethanolammonium cation and anions of sulfuric, nitric, phosphoric, and phosphorus acids to provide essential insight into these phenomena at the molecular level. It was shown that every structure is stabilized through multiple H bonds between the protons in the N-H and O-H groups of the cation and different oxygen atoms of the anion acid. Using atoms in molecules topological parameters and natural bond orbital analysis, we determined the nature and strength of these interactions. Our calculations suggest that the N-H group of the cation has more proton donor-like character than the O-H group that makes the N-H···O hydrogen bonds stronger. A close relation between the binding energies of these ion pairs and experimental melting points was established: the smaller the absolute value of the binding energy between ions, the lower is the melting point.

Mixtures of glyme and aprotic-protic ionic liquids as electrolytes for energy storage devices

NASA Astrophysics Data System (ADS)

Stettner, T.; Huang, P.; Goktas, M.; Adelhelm, P.; Balducci, A.

2018-05-01

Ionic liquids (ILs) have been proven to be promising electrolytes for electrochemical energy storage devices such as supercapacitors and lithium ion batteries. In the last years, due to deficiency in storage of lithium on earth, innovative systems, such as sodium-based devices, attracted considerable attention. IL-based electrolytes have been proposed also as electrolytes for these devices. Nevertheless, in the case of these systems, the advantages and limits of IL-based electrolytes need to be further investigated. In this work we report an investigation about the chemical-physical properties of mixtures containing bis(2-methoxyethyl)ether diglyme (2G), which is presently considered as one of the most interesting solvents for sodium-based devices, and the ionic liquids 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (Pyr14TFSI) and 1-butylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PyrH4TFSI). The conductivities, viscosities, and densities of several mixtures of 2G and these ILs have been investigated. Furthermore, their impact on the electrochemical behaviour of activated carbon composite electrodes has been considered. The results of this investigation indicate that these mixtures are promising electrolytes for the realization of advanced sodium-based devices.

Hydrogen bonding in ionic liquids.

PubMed

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

2015-03-07

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

Activity and conformation of lysozyme in molecular solvents, protic ionic liquids (PILs) and salt-water systems.

PubMed

Wijaya, Emmy C; Separovic, Frances; Drummond, Calum J; Greaves, Tamar L

2016-09-21

Improving protein stabilisation is important for the further development of many applications in the pharmaceutical, specialty chemical, consumer product and agricultural sectors. However, protein stabilization is highly dependent on the solvent environment and, hence, it is very complex to tailor protein-solvent combinations for stable protein maintenance. Understanding solvent features that govern protein stabilization will enable selection or design of suitable media with favourable solution environments to retain protein native conformation. In this work the structural conformation and activity of lysozyme in 29 solvent systems were investigated to determine the role of various solvent features on the stability of the enzyme. The solvent systems consisted of 19 low molecular weight polar solvents and 4 protic ionic liquids (PILs), both at different water content levels, and 6 aqueous salt solutions. Small angle X-ray scattering, Fourier transform infrared spectroscopy and UV-vis spectroscopy were used to investigate the tertiary and secondary structure of lysozyme along with the corresponding activity in various solvation systems. At low non-aqueous solvent concentrations (high water content), the presence of solvents and salts generally maintained lysozyme in its native structure and enhanced its activity. Due to the presence of a net surface charge on lysozyme, electrostatic interactions in PIL-water systems and salt solutions enhanced lysozyme activity more than the specific hydrogen-bond interactions present in non-ionic molecular solvents. At higher solvent concentrations (lower water content), solvents with a propensity to exhibit the solvophobic effect, analogous to the hydrophobic effect in water, retained lysozyme native conformation and activity. This solvophobic effect was observed particularly for solvents which contained hydroxyl moieties. Preferential solvophobic effects along with bulky chemical structures were postulated to result in less competition with water at the specific hydration layer around the protein, thus reducing protein-solvent interactions and retaining lysozyme's native conformation. The structure-property links established in this study are considered to be applicable to other proteins.

Stability and activity of lysozyme in stoichiometric and non-stoichiometric protic ionic liquid (PIL)-water systems

NASA Astrophysics Data System (ADS)

Wijaya, Emmy C.; Separovic, Frances; Drummond, Calum J.; Greaves, Tamar L.

2018-05-01

There has been a substantial increase in enzyme applications within the biochemical and pharmaceutical industries, for example, as industrial biocatalysts. However, enzymes have narrow marginal stability which makes them prone to become inactive and/or denature with a slight change in the solvent environment. Typically industrial applications require harsher solvent environments than enzyme native environments, and hence there is a need to understand solvent-protein interactions in order to develop strategies to maintain, or enhance, the enzymatic activity under industrially relevant solvent conditions. Previously we have shown that protic ionic liquids (PILs) with water can have a stabilising effect on lysozyme, with a large variation dependent on which PIL ions are present, and the water concentration [E. C. Wijaya et al., Phys. Chem. Chem. Phys. 18(37), 25926-25936 (2016)]. Here we extend on this work using non-stoichiometric aqueous PIL solvents to investigate, and isolate, the role of pH and ionicity on enzymes. We have used the PILs ethylammonium nitrate (EAN) and ethanolammonium formate (EOAF) since our previous work has identified these as good solvents for lysozyme. Solvent libraries were made from these two PILs with an additional precursor acid or base to modify the acidity/basicity of the neutral stoichiometric PIL, and with water added, to have solutions with 4-17 mol. % of the PIL ions in water. Molar ratios of base:acid were varied between 1:1.05 and 2:1 for EAN and 1:1.25 and 2:1 for EOAF, which enabled from highly basic to highly acidic solutions to be obtained. This was to modify the acidity/basicity of the neutral stoichiometric PILs, without the addition of buffers. The structure and stability of hen egg white lysozyme (HEWL) were explored under these solvent conditions using synchrotron small angle X-ray scattering (SAXS), Fourier transform infrared (FTIR), and activity assays. The radius of gyration and Kratky plots obtained from the SAXS data showed little change with varying ionicity or acid:base ratio. FTIR showed that α-helix was maintained in all, except for the most acidic solvent conditions. The activity data show that HEWL was active between pH 0 and 11 for the EA:N-water system and pH 4.4 and 11 for the EOA:F-water system. This work indicates that ionic liquids have the potential to enable enzymes to maintain activity across a broader range of solvent conditions.

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

PubMed Central

Rollins, Julie B.; Conboy, John C.

2010-01-01

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

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

PubMed

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

2014-09-08

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. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Phase Behavior and Physical Properties of New Biobased Ionic Liquid Crystals.

PubMed

Toledo Hijo, Ariel A C; Maximo, Guilherme J; Costa, Mariana C; Cunha, Rosiane L; Pereira, Jorge F B; Kurnia, Kiki A; Batista, Eduardo A C; Meirelles, Antonio J A

2017-04-13

Protic ionic liquids (PILs) have emerged as promising compounds and attracted the interest of the industry and the academy community, due to their easy preparation and unique properties. In the context of green chemistry, the use of biocompounds, such as fatty acids, for their synthesis could disclose a possible alternative way to produce ILs with a low or nontoxic effect and, consequently, expanding their applicability in biobased processes or in the development of bioproducts. This work addressed efforts to a better comprehension of the complex solid-[liquid crystal]-liquid thermodynamic equilibrium of 20 new PILs synthesized by using fatty acids commonly found in vegetable oils, as well as their rheological profile and self-assembling ability. The work revealed that their phase equilibrium and physical properties are significantly impacted by the structure of the ions used for their synthesis. The use of unsaturated fatty acids and bis(2-hydroxyethyl)ammonium for the synthesis of these biobased ILs led to a drastic decreasing of their melting temperatures. Also, the longest alkyl chain fatty acids promoted higher self-assembling and more stable mesophases. Besides their sustainable appeal, the marked high viscosity, non-Newtonian profile, and very low critical micellar concentration values of the PIL crystals here disclosed make them interesting renewable compounds with potential applications as emulsifiers, stabilizers, thickeners, or biolubricants.

Theoretical and Experimental Insights into the Dissociation of 2-Hydroxyethylhydrazinium Nitrate Clusters Formed via Electrospray.

PubMed

Patrick, Amanda L; Vogelhuber, Kristen M; Prince, Benjamin D; Annesley, Christopher J

2018-03-01

Ionic liquids are used for myriad applications, including as catalysts, solvents, and propellants. Specifically, 2-hydroxyethylhydrazinium nitrate (HEHN) has been developed as a chemical propellant for space applications. The gas-phase behavior of HEHN ions and clusters is important in understanding its potential as an electrospray thruster propellant. Here, the unimolecular dissociation pathways of two clusters are experimentally observed, and theoretical modeling of hydrogen bonding and dissociation pathways is used to help rationalize those observations. The cation/deprotonated cation cluster [HEH 2 - H] + , which is observed from electrospray ionization, is calculated to be considerably more stable than the complementary cation/protonated anion adduct, [HEH + HNO 3 ] + , which is not observed experimentally. Upon collisional activation, a larger cluster [(HEHN) 2 HEH] + undergoes dissociation via loss of nitric acid at lower collision energies, as predicted theoretically. At higher collision energies, additional primary and secondary loss pathways open, including deprotonated cation loss, ion-pair loss, and double-nitric-acid loss. Taken together, these experimental and theoretical results contribute to a foundational understanding of the dissociation of protic ionic liquid clusters in the gas phase.

On the decoupling of relaxation modes in a molecular liquid caused by isothermal introduction of 2 nm structural inhomogeneities.

PubMed

Ueno, Kazuhide; Angell, C Austen

2011-12-08

To support a new interpretation of the origin of the dynamic heterogeneity observed pervasively in fragile liquids as they approach their glass transition temperatures T(g), we demonstrate that the introduction of ~2 nm structural inhomogeneities into a homogeneous glass former leads to a decoupling of diffusion from viscosity similar to that observed during the cooling of orthoterphenyl (OTP) below T(A,) where Arrhenius behavior is lost. Further, the decoupling effect grows stronger as temperature decreases (and viscosity increases). The liquid is cresol, and the ~2 nm inhomogeneities are cresol-soluble asymmetric derivatized tetrasiloxy-based (polyhedral oligomeric silsesquioxane (POSS)) molecules. The decoupling is the phenomenon predicted by Onsager in discussing the approach to a liquid-liquid phase separation with decreasing temperature. In the present case the observations support the notion of a polyamorphic transition in fragile liquids that is hidden below the glass transition. A similar decoupling can be expected as a globular protein is dissolved in dilute aqueous solutions or in protic ionic liquids. © 2011 American Chemical Society

Influence of protic ionic liquids on the structure and stability of succinylated Con A.

PubMed

Attri, Pankaj; Venkatesu, Pannuru

2012-01-01

We report the synthesis of a series of ionic liquids (ILs) from various ions having different kosmotropicity including dihydrogen phosphate (H(2)PO(4)(-)), hydrogen sulfate (HSO(4)(-)) and acetate (CH(3)COO(-)) as anions and chaotropic cation such as trialkylammonium cation. To characterize the biomolecular interactions of ILs with protein, we have explored the stability of succinylated Con A (S Con A) in the presence of these aqueous ILs, which are varied combinations of kosmotropic anion with chaotropic cation such as triethylammonium dihydrogen phosphate [(CH(3)CH(2))(3)NH][H(2)PO(4)] (TEAP), trimethylammonium acetate [(CH(3))(3)NH][CH(3)COO] (TMAA), trimethylammonium dihydrogen phosphate [(CH(3))(3)NH][H(2)PO(4)] (TMAP) and trimethylammonium hydrogen sulfate [(CH(3))(3)NH][HSO(4)] (TMAS). Circular dichroism (CD) and fluorescence experiments have been used to characterize the stability of S Con A by ILs. Our data distinctly demonstrate that the long alkyl chain IL TEAP is a strong stabilizer for S Con A. Further, our experimental results reveal that TEAP is an effective refolding enhancer for S Con A from a thermally denatured protein structure. Copyright © 2012 Elsevier B.V. All rights reserved.

Dielectric response and transport properties of alkylammonium formate ionic liquids

NASA Astrophysics Data System (ADS)

Nazet, Andreas; Buchner, Richard

2018-05-01

Dielectric relaxation spectra of three members of the alkylammonium formate family of protic ionic liquids (PILs), namely, ethylammonium formate (EAF), n-butylammonium formate (BuAF), and n-pentylammonium formate (PeAF), as well as the pseudo-PIL triethylamine + formic acid (molar ratio 1:2; TEAF) have been studied over a wide frequency (50 MHz to 89 GHz) and temperature range (5-65 °C), complemented by measurements of their density, viscosity, and conductivity. It turned out that the dominating relaxation of EAF, BuAF, and PeAF arises from both cation and anion reorientations which are synchronized in their dynamics due to hydrogen bonding. Amplitudes and relaxation times of this mode reflect the—compared to nitrate—different nature of H bonding between the formate anion and ethylammonium cation, as well as increasing segregation of the PIL structure into polar and non-polar domains. The TEAF data suggest that its dominating relaxation is due to the rotation of the complex triethylamineṡ(formic acid)2 in which no significant proton transfer to an ion pair occurred. Weak dissociation of this complex into ions was postulated to account for the high conductivity of TEAF.

Estudio del comportamiento tribologico y de las interacciones de superficie de nuevos nanofluidos ionicos

NASA Astrophysics Data System (ADS)

Espinosa Rodriguez, Tulia

Ionic liquids are molten salts which are liquid at room temperature or at low temperatures and present a unique combination of properties. In the present work, we focus on their use as lubricants in complex tribological problems such as the lubrication of metals that slide against themselves, the development of water based lubricants and new self-lubricated surfaces. When it is difficult to reduce friction and wear by lubrication, as in the case of magnesium alloys, ionic liquids are studied as protective coatings precursors. Surface interactions and corrosion processes with protic and aprotic ionic liquids on copper and steel have been determined in order to develop new lubricants and lubricant additives. In the copper/copper contact, all ionic liquids present better tribological performance than the polyalphaolefin synthetic oil, except for the oleate derivative. New protic ionic liquids are not only exceptional lubricants of the steel/sapphire contact as neat lubricants, but when they are used as additives in water, the formation of a boundary layer after water evaporation occurs, thus reducing friction and wear. The formation of this boundary layer on steel under static conditions is described in order to prevent the running-in period with respect to the solution of ionic liquid in water. The best lubricating behaviour for the copper/copper contact and also for the steel/sapphire contact is obtained for the diprotic ammonium dianionic adipate, that has two carboxylate groups in its anion. A higher polarity and a higher number of ammonium protons, carboxylate and hydroxyl groups would give rise to stronger surface interaction with the metal surfaces and more stable boundary films. The tribological performance of new aprotic thiazolium ionic liquids and commercial aprotic imidazolium ionic liquids has been compared as lubricants of the steel/sapphire contact, obtaining the best results for the bis(trifluoromethanesulfonyl)imide derivatives, and also preventing tribocorrosion processes. The formation of a coating layer on magnesium alloys from phosphonate imidazolium ionic liquids by immersion and by chronoamperometry has been described. The new coatings reduce the abrasive wear in the magnesium-aluminium alloy but they are not effective in the magnesium-zinc alloy, which prevent the formation of continuous coatings. Los liquidos ionicos son sales liquidas a temperatura ambiente o bajas temperaturas que presentan excelentes propiedades fisico-quimicas. En el presente trabajo se estudian como lubricantes en problemas tribologicos complejos como la lubricacion de metales contra si mismos, el desarrollo de lubricantes base agua y de nuevas superficies autolubricadas. Cuando no es posible reducir la friccion y desgaste mediante lubricacion, como en las aleaciones de magnesio, los liquidos ionicos se han estudiado como precursores de recubrimientos protectores. Se han determinado las interacciones superficiales y los procesos de corrosion sobre cobre y sobre acero con diferentes liquidos ionicos proticos y aproticos para desarrollar nuevos lubricantes y aditivos. En el contacto cobre/cobre, excepto el liquido ionico protico derivado del oleato, todos los liquidos ionicos estudiados presentan mejor comportamiento tribologico que el lubricante comercial Polialfaolefina 6. En el contacto acero/zafiro, los nuevos liquidos ionicos proticos son buenos lubricantes cuando se utilizan en estado puro, y, como aditivos en agua, generan peliculas adsorbidas sobre la superficie del metal reduciendo la friccion y el desgaste tras la evaporacion del agua. Para evitar el periodo de alta friccion inicial en presencia de agua, se han generado peliculas superficiales de liquido ionico sobre el acero en condiciones estaticas. El mejor comportamiento lubricante tanto en el contacto cobre/cobre como en el contacto acero/zafiro se obtiene para el liquido ionico protico derivado del anion adipato, con dos grupos carboxilicos. Las interacciones de los grupos hidroxilo y carboxilato con la superficie metalica y los puentes de hidrogeno entre cation y anion podrian ser los responsables del buen comportamiento tribologico. Se ha comparado el comportamiento tribologico de los liquidos ionicos aproticos derivados de imidazolio y tiazolio como lubricantes del contacto acero/zafiro, obteniendose los mejores resultados para los derivados del anion bis(trifluorometanosulfonil)imida, que evita a su vez los procesos de tribocorrosion. Se han generado recubrimientos sobre aleaciones de magnesio con tres liquidos ionicos derivados del anion fosfonato, tanto por inmersion como mediante cronoamperometria. Los nuevos recubrimientos reducen el dano superficial por deslizamiento o abrasion de la aleacion magnesio-aluminio pero no de la aleacion magnesio-cinc, que impide la formacion de recubrimientos continuos.

Association in ethylammonium nitrate-dimethyl sulfoxide mixtures: First structural and dynamical evidences

DOE Office of Scientific and Technical Information (OSTI.GOV)

Russina, Olga; Macchiagodena, Marina; Kirchner, Barbara

2015-01-01

Here we report the first structural and dynamic investigation on ethylammonium nitrate, a representative protic Ionic liquid, and dimethylsulfoxide. By using joined x/ray and neutron diffraction, we exploit the EPSR approach to extract structural information at atomistic level. EAN/DMSO turns out to be homogeneous at microscopic scales and indications for the existence of a structural leit motiv with stoichiometric composition 2DMSO:1EAN are found. Dielectric spectroscopy is used to access the relaxation map of the DMSO:EAN = 60:40 mixture. No crystallisation is detected and three relaxation processes could be characterised. Overall this study provides new indications of strict analogies between watermore » and ethylammonium nitrate. (c) 2014 Elsevier B.V. All rights reserved.« less

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

PubMed

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

2012-06-07

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

Research on solar pumped liquid lasers

NASA Technical Reports Server (NTRS)

Schneider, R. T.; Kurzweg, U. H.; Cox, J. D.; Weinstein, N. H.

1983-01-01

A solar pumped liquid laser that can be scaled up to high power (10Mw CW) for space applications was developed. Liquid lasers have the inherent advantage over gases in that they provide much higher lasant densities and thus high power densities. Liquids also have inherent advantages over solids in that they have much higher damage thresholds and are much cheaper to produce for large scale applications. Among the liquid laser media that are potential candidates for solar pumping, the POC13:Nd(3+):ZrC14 liquid was chosen for its high intrinsic efficiency as well as its relatively good stability against decomposition due to protic contamination. The development and testing of the laser liquid and the development of a large solar concentrator to pump the laser was emphasized. The procedure to manufacture the laser liquid must include diagnostic tests of the solvent purity (from protic contamination) at various stages in the production process.

Effect of low water content in protic ionic liquid on ions electrosorption in porous carbon: application to electrochemical capacitors.

PubMed

Gorska, B; Timperman, L; Anouti, M; Béguin, F

2017-05-10

The effect of low water content (<20, 150, 1000, 10 000 ppm) in triethylammonium bis[(trifluoromethyl)sulfonyl]imide - [(C 2 H 5 ) 3 N + H][TFSI - ] - protic ionic liquid (PIL) on the performance of activated carbon (AC) electrodes as well as AC/AC electrochemical capacitors (ECs) is reported. Under negative polarization, hydrogen electrosorption onto carbon is enhanced along with the increase of water content in PIL, whereas the resulting desorption peaks are shifted to lower potential values, evidencing lower sorption energy when hydrogen is stored from moisture containing PIL. Cyclic voltammetry (CV) investigations on PIL-based ECs demonstrated that the evolution of the Stern layer nanostructure at positive and negative potentials is asymmetrical. The results revealed comparable electrochemical performance for PIL containing 150 and 1000 ppm of H 2 O, due to similar operation of the positive electrode, where [TFSI - ] anions are adsorbed in the outer Helmholtz plane, and the negative one, where hydrogen is stored through the reduction of the intermediate hydronium cation. By contrast, a cell with "dry" PIL (<20 ppm of water) displayed a distinctive operation due to hydrogen electrosorption directly through reduction of the protonated cation, and selective adsorption of [TFSI - ] anions, which occurs thanks to the high polarizability and image force (IF) created by their induced charge. Galvanostatic cycling with potential limitation (GCPL) showed comparable capacitance values whatever the water content in PILs up to 1000 ppm, yet electrochemical impedance spectroscopy (EIS) revealed higher capacitance as well as better retention at higher frequencies with the PIL containing 150 ppm of water. Hence, 150 ppm is reasoned to be an optimal value for diffusion and adsorption of ions. The nature of current collectors (aluminum or stainless steel) has a determining role in their polarization behavior, and consequently the potential range of electrodes as well as ion diffusion into the activated carbon porosity, influencing the observed capacitance values (C EIS/2.0V : 170 vs. 128 F g -1 , for Al and SSt, respectively).

Is There Any Preferential Interaction of Ions of Ionic Liquids with DMSO and H2O? A Comparative Study from MD Simulation.

PubMed

Zhao, Yuling; Wang, Jianji; Wang, Huiyong; Li, Zhiyong; Liu, Xiaomin; Zhang, Suojiang

2015-06-04

Recently, some binary ionic liquid (IL)/cosolvent systems have shown better performance than the pure ILs in fields such as CO2 absorption, catalysis, cellulose dissolution, and electrochemistry. However, interactions of ILs with cosolvents are still not well understood at the molecular level. In this work, H2O and DMSO were chosen as the representative protic and aprotic solvents to study the effect of cosolvent nature on solvation of a series of ILs by molecular dynamics simulations and quantum chemistry calculations. The concept of preferential interaction of ions was proposed to describe the interaction of cosolvent with cation and anion of the ILs. By comparing the interaction energies between IL and different cosolvents, it was found that there were significantly preferential interactions of anions of the ILs with water, but the same was not true for the interactions of cations/anions of the ILs with DMSO. Then, a detailed analysis and comparison of the interactions in IL/cosolvent systems, hydrogen bonds between cations and anions of the ILs, and the structure of the first coordination shells of the cations and the anions were performed to reveal the existing state of ions at different molar ratios of the cosolvent to a given IL. Furthermore, a systematic knowledge for the solvation of ions of the ILs in DMSO was given to understand cellulose dissolution in IL/cosolvent systems. The conclusions drawn from this study may provide new insight into the ionic solvation of ILs in cosolvents, and motivate further studies in the related applications.

Unusual solvatochromic absorbance probe behaviour within mixtures of poly(ethylene glycol)-400 + ionic liquid, [bmim][Tf2N

NASA Astrophysics Data System (ADS)

Ali, Anwar; Ali, Maroof; Malik, Nisar Ahmad; Uzair, Sahar

2014-03-01

The potentially green solvents made up of ionic liquids (ILs) and poly(ethylene glycols) may have wide range of the applications in many chemical and biochemical fields. In the present work, solvatochromic absorbance probe behaviour is used to assess the physicochemical properties of the mixtures composed of PEG-400 + IL, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [bmim][Tf2N]. Lowest energy intramolecular charge-transfer absorbance maxima of a betaine dye, i.e., ETN , indicates the dipolarity/polarizability and/or hydrogen-bond donating (HBD) acidity of the [bmim][Tf2N] + PEG-400 mixtures to be even higher than that of neat [bmim][Tf2N], the solution component with higher dipolarity/polarizability and/or HBD acidity. Dipolarity/polarizability (π∗) obtained separately from the electronic absorbance response of probe N,N-diethyl-4-nitroaniline, and the HBD acidity (α) of PEG-400 + [bmim][Tf2N] mixtures are also observed to be anomalously high. A comparative study of the PEG + IL mixtures has also been done with PEG-400 + molecular organic solvents (protic polar [methanol], aprotic polar [N,N-dimethylformamide], and non polar, [benzene]) mixtures, but these mixtures do not show this type of unusual behaviour. A four-parameter simplified combined nearly ideal binary solvent/Redlich-Kister (CNIBS/R-K) equation is shown to satisfactorily predict the solvatochromic parameters within PEG-400 + different solvent mixtures.

Photochemical oxidation of water and reduction of polyoxometalate anions at interfaces of water with ionic liquids or diethylether

PubMed Central

Bernardini, Gianluca; Wedd, Anthony G.; Zhao, Chuan; Bond, Alan M.

2012-01-01

Photoreduction of [P2W18O62]6-, [S2Mo18O62]4-, and [S2W18O62]4- polyoxometalate anions (POMs) and oxidation of water occurs when water–ionic liquid and water–diethylether interfaces are irradiated with white light (275–750 nm) or sunlight. The ionic liquids (ILs) employed were aprotic ([Bmim]X; Bmim = (1-butyl-3-methylimidazolium,X = BF4,PF6) and protic (DEAS = diethanolamine hydrogen sulphate; DEAP = diethanolamine hydrogen phosphate). Photochemical formation of reduced POMs at both thermodynamically stable and unstable water–IL interfaces led to their initial diffusion into the aqueous phase and subsequent extraction into the IL phase. The mass transport was monitored visually by color change and by steady-state voltammetry at microelectrodes placed near the interface and in the bulk solution phases. However, no diffusion into the organic phase was observed when [P2W18O62]6- was photo-reduced at the water–diethylether interface. In all cases, water acted as the electron donor to give the overall process: 4POM + 2H2O + hν → 4POM- + 4H+ + O2. However, more highly reduced POM species are likely to be generated as intermediates. The rate of diffusion of photo-generated POM- was dependent on the initial concentration of oxidized POM and the viscosity of the IL (or mixed phase system produced in cases in which the interface is thermodynamically unstable). In the water-DEAS system, the evolution of dioxygen was monitored in situ in the aqueous phase by using a Clark-type oxygen sensor. Differences in the structures of bulk and interfacial water are implicated in the activation of water. An analogous series of reactions occurred upon irradiation of solid POM salts in the presence of water vapor. PMID:22753501

Comparison of two protic ionic liquid behaviors in the presence of an electric field using molecular dynamics

NASA Astrophysics Data System (ADS)

Mehta, Neil A.; Levin, Deborah A.

2017-12-01

The effects of an external electric field on two ionic liquids (ILs) are investigated using molecular dynamics electrospray simulations of ethylammonium nitrate (EAN) and ethanolammonium nitrate (EOAN). In the absence of an external electric field, long alkyl chains were observed in EAN but not in EOAN. When the electric field was applied, the anions of both ILs formed a barrier along the applied field, but only in EAN did this barrier result in a static bilayer composed of two parallel layers of cations and anions. The primary hydrogen bonds (HBs) connecting the EAN cations and anions were formed between the ammonium and the nitrate groups. In contrast, they were formed between the ammonium as well as the hydroxyl groups and the nitrate groups in EOAN. The applied electric field was found effective in reducing the number of O1-HO⋯O type HBs but was less effective against the N-HN⋯O type HBs. It was observed that the N-C1-CM backbone angles of EAN allowed for greater storage of the energy supplied by the electric field in the form of torsional degree of freedom compared to the N-C1-CM angles of EOAN. The combination of stronger HBs and higher energy storage in the N-C1-CM covalent angle in EAN results in a stronger resistance of ion emission from the bulk compared to EOAN.

Green and Efficient Processing of Cinnamomum cassia Bark by Using Ionic Liquids: Extraction of Essential Oil and Construction of UV-Resistant Composite Films from Residual Biomass.

PubMed

Mehta, Mohit J; Kumar, Arvind

2017-12-14

There is significant interest in the development of a sustainable and integrated process for the extraction of essential oils and separation of biopolymers by using novel and efficient solvent systems. Herein, cassia essential oil enriched in coumarin is extracted from Cinnamomum cassia bark by using a protic ionic liquid (IL), ethylammonium nitrate (EAN), through dissolution and the creation of a biphasic system with the help of diethyl ether. The process has been perfected, in terms of higher biomass dissolution ability and essential oil yield through the addition of aprotic ILs (based on the 1-butyl-3-methylimidazolium (C 4 mim) cation and chloride or acetate anions) to EAN. After extraction of oil, cellulose-rich material and free lignin were regenerated from biomass-IL solutions by using a 1:1 mixture of acetone-water. The purity of the extracted essential oil and biopolymers were ascertained by means of FTIR spectroscopy, NMR spectroscopy, and GC-MS techniques. Because lignin contains UV-blocking chromophores, the oil-free residual lignocellulosic material has been directly utilized to construct UV-light-resistant composite materials in conjunction with the biopolymer chitosan. Composite material thus obtained was processed to form biodegradable films, which were characterized for mechanical and optical properties. The films showed excellent UV-light resistance and mechanical properties, thereby making it a material suitable for packaging and light-sensitive applications. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Functionalized Agarose Self-Healing Ionogels Suitable for Supercapacitors.

PubMed

Trivedi, Tushar J; Bhattacharjya, Dhrubajyoti; Yu, Jong-Sung; Kumar, Arvind

2015-10-12

Agarose has been functionalized (acetylated/carbanilated) in an ionic liquid (IL) medium of 1-butyl-3-methylimidazolium acetate at ambient conditions. The acetylated agarose showed a highly hydrophobic nature, whereas the carbanilated agarose could be dissolved in water as well as in the IL medium. Thermoreversible ionogels were obtained by cooling the IL sols of carbanilated agarose at room temperature. The ionogel prepared from a protic-aprotic mixed-IL system (1-butyl-3-methylimidazolium chloride and N-(2-hydroxyethyl)ammonium formate) demonstrated a superior self-healing property, as confirmed from rheological measurements. The superior self-healing property of such an ionogel has been attributed to the unique inter-intra hydrogen-bonding network of functional groups inserted in the agarose. The ionogel was tested as a flexible solid electrolyte for an activated-carbon-based supercapacitor cell. The measured specific capacitance was found to be comparable with that of a liquid electrolyte system at room temperature and was maintained for up to 1000 charge-discharge cycles. Such novel functionalized-biopolymer self-healing ionogels with flexibility and good conductivity are desirable for energy-storage devices and electronic skins with superior lifespans and robustness. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gas Evolution in Activated-Carbon-Based Supercapacitors with Protic Deep Eutectic Solvent as Electrolyte.

PubMed

Phadke, Satyajit; Amara, Samia; Anouti, Mérièm

2017-09-06

One of the primary causes of aging in supercapacitors are the irreversible faradaic reactions occurring near the operating-voltage limit that lead to the production of gases resulting in device swelling, increased resistance, and lowering of the capacitance. In this study, a protic deep eutectic solvent (DES) consisting of mixture of lithium bis(fluorosulfonyl)imide (LiFSI) with formamide (FMD) as H-bond donor (x LiFSI =0.25; C=2.5 m LiFSI) is investigated as electrolyte for activated carbon (AC)-based electrical double layer capacitors (EDLCs). Characterization of the viscosity, conductivity, and the ionicity of the electrolyte in a wide range of temperatures indicates >88 % salt dissociation. In situ pressure measurements are performed to understand the effect of cycling conditions on the rate of gas generation, quantified by the in operando pressure variation dP/dt. These measurements demonstrate that about 25 % of the faradaic reactions leading to gas generation are electrochemically reversible. Cell aging studies demonstrate promising potential of the LiFSI/FMD as a protic electrolyte for AC-based EDLCs and high energy density close to 30 Wh kg -1 at 2.4 V. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Temperature dependence measurements and structural characterization of trimethyl ammonium ionic liquids with a highly polar solvent.

PubMed

Attri, Pankaj; Venkatesu, Pannuru; Hofman, T

2011-08-25

We report the synthesis and characterization of a series of an ammonium ionic liquids (ILs) containing acetate, dihydrogen phosphate, and hydrogen sulfate anions with a common cation. To characterize the thermophysical properties of these newly synthesized ILs with the highly polar solvent N,N-dimethylformamide (DMF), precise measurements such as densities (ρ) and ultrasonic sound velocities (u) over the whole composition range have been performed at atmospheric pressure and over wide temperature ranges (25-50 °C). The excess molar volume (V(E)) and the deviation in isentropic compressibilities (Δκ(s)) were predicted using these temperature dependence properties as a function of the concentration of ILs. The Redlich-Kister polynomial was used to correlate the results. The ILs investigated in the present study included trimethylammonium acetate [(CH(3))(3)NH][CH(3)COO] (TMAA), trimethylammonium dihydrogen phosphate [(CH(3))(3)NH][H(2)PO(4)] (TMAP), and trimethylammonium hydrogen sulfate [(CH(3))(3)NH][HSO(4)] (TMAS). The intermolecular interactions and structural effects were analyzed on the basis of the measured and the derived properties. In addition, the hydrogen bonding between ILs and DMF has been demonstrated using semiempirical calculations with help of Hyperchem 7. A qualitative analysis of the results is discussed in terms of the ion-dipole, ion-pair interactions, and hydrogen bonding between ILs and DMF molecules and their structural factors. The influence of the anion of the protic IL, namely, acetate (CH(3)COO), dihydrogen phosphate (H(2)PO(4)), and hydrogen sulfate (HSO(4)), on the thermophysical properties is also provided. © 2011 American Chemical Society

Ionic liquids-mediated interactions between nanorods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Zhou; Zhang, Fei; Huang, Jingsong

Surface forces mediated by room-temperature ionic liquids (RTILs) play an essential role in diverse applications including self-assembly, lubrication, and electrochemical energy storage. In this work, using molecular simulations we study the interactions between two nanorods immersed in model RTILs at rod-rod separations where both structural and double layer forces are important. The interaction force between neutral rods oscillates as the two rods approach each other, similar to the classical structural forces. Such oscillatory force originates from the density oscillation of RTILs near each rod and is affected by the packing constraints imposed by the neighboring rods. The oscillation period andmore » decay length of the oscillatory force are mainly dictated by the ion density distribution near isolated nanorods. When charges are introduced on the rods, the interaction force remains short-range and oscillatory, similar to the interactions between planar walls mediated by some protic RTILs reported earlier. Nevertheless, introducing net charges to the rods greatly changes the rod-rod interactions, e.g., by delaying the appearance of the first force trough and increasing the oscillation period and decay length of the interaction force. The oscillation period and decay length of the oscillatory force and free energy are commensurate with those of the space charge density near an isolated, charged rod. The free energy of rod-rod interactions reaches local minima (maxima) at rod-rod separations when the space charges near the two rods interfere constructively (destructively). Here, the insight on the short-range interactions between nanorods in RTILs helps guide the design of novel materials, e.g., crystalline ion gels based on rigid-rod polyanions and RTILs.« less

Ionic liquids-mediated interactions between nanorods

DOE PAGES

Yu, Zhou; Zhang, Fei; Huang, Jingsong; ...

2017-10-06

Surface forces mediated by room-temperature ionic liquids (RTILs) play an essential role in diverse applications including self-assembly, lubrication, and electrochemical energy storage. In this work, using molecular simulations we study the interactions between two nanorods immersed in model RTILs at rod-rod separations where both structural and double layer forces are important. The interaction force between neutral rods oscillates as the two rods approach each other, similar to the classical structural forces. Such oscillatory force originates from the density oscillation of RTILs near each rod and is affected by the packing constraints imposed by the neighboring rods. The oscillation period andmore » decay length of the oscillatory force are mainly dictated by the ion density distribution near isolated nanorods. When charges are introduced on the rods, the interaction force remains short-range and oscillatory, similar to the interactions between planar walls mediated by some protic RTILs reported earlier. Nevertheless, introducing net charges to the rods greatly changes the rod-rod interactions, e.g., by delaying the appearance of the first force trough and increasing the oscillation period and decay length of the interaction force. The oscillation period and decay length of the oscillatory force and free energy are commensurate with those of the space charge density near an isolated, charged rod. The free energy of rod-rod interactions reaches local minima (maxima) at rod-rod separations when the space charges near the two rods interfere constructively (destructively). Here, the insight on the short-range interactions between nanorods in RTILs helps guide the design of novel materials, e.g., crystalline ion gels based on rigid-rod polyanions and RTILs.« less

Tandem derivatization combined with salting-out assisted liquid-liquid microextraction for determination of biothiols in urine by gas chromatography-mass spectrometry.

PubMed

Tsai, Chia-Ju; Liao, Fang-Yi; Weng, Jing-Ru; Feng, Chia-Hsien

2017-11-17

Detection of polar organic compounds (POCs) using gas chromatography (GC) is not straightforward due to high polarity, hydrophilicity, and low volatility of POCs. In this study, we report a tandem microwave-assisted derivatization method combined with salting-out assisted liquid-liquid microextraction (SALLME) to modify successively the polar groups of POCs in protic and aprotic solvents. Biothiols (cysteine and homocysteine) served as a proof of concept for this method because they possess three polar groups (thiol, amine, and carboxyl); the derivatizing reagent was 3,4,5-trifluorobenzyl bromide (Br-TFB) for alkylation. The solubility of the POCs in the protic or aprotic reaction medium affected the number of TFB molecules attached. Using the tandem derivatization with Br-TFB, the thiol and amine groups of biothiols were alkylated in the protic system, and the carboxylic groups of biothiols were alkylated in the aprotic system. The developed method was then successfully applied to measure biothiols in human urine. Because of the complex urine matrix and the lack of urine samples without endogenous biothiols, the standard addition method was utilized to avoid the matrix effect, check the recovery, and calculate the initial biothiol content in the urine. Regarding the linearity of the standard addition curves, the coefficient of determination was >0.996, and the linear regression showed satisfactory reproducibility with a relative standard deviation <3.9% for the slope and <8.8% for the intercept. The levels of cysteine and homocysteine in healthy human urine ranged from 28.8 to 111μmolL -1 and from 1.28 to 3.73μmolL -1 , respectively. The proposed method effectively increased the sensitivity of GC-MS assays of water-soluble compounds in human urine. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of Extrinsic and Intrinsic Proton Activity on The Mechanism of Oxygen Reduction in Ionic Liquids

NASA Astrophysics Data System (ADS)

Zeller, Robert August

Mechanisms for oxygen reduction are proposed for three distinct cases covering two ionic liquids of fundamentally different archetypes and almost thirty orders of magnitude of proton activity. Proton activity is treated both extrinsically by varying the concentration and intrinsically by selecting proton donors with a wide range of aqueous pKa values. The mechanism of oxygen reduction in ionic liquids is introduced by way of the protic ionic liquid (pIL) triethylammonium triflate (TEATf) which shares some similarities with aqueous acid solutions. Oxygen reduction in TEATf begins as the one electron rate limited step to form superoxide, O2 *-, which is then rapidly protonated by the pIL cation forming the perhydroxyl radical, HO2*. The perhydroxyl radical is further reduced to peroxidate (HO2-) and hydrogen peroxide in proportions in accordance with their pKa. The reaction does not proceed beyond this point due to the adsorption of the conjugate base triethylammine interfering with the disproportionation of hydrogen peroxide. This work demonstrates that this mechanism is consistent across Pt, Au, Pd, and Ag electrodes. Two related sets of experiments were performed in the inherently aprotic ionic liquid 1-butyl-2,3-dimethylimidazolium triflate (C4dMImTf). The first involved the titration of acidic species of varying aqueous pKa into the IL while monitoring the extent of oxygen reduction as a function of pKa and potential on Pt and glassy carbon (GC) electrodes. These experiments confirmed the greater propensity of Pt to reduce oxygen by its immediate and abrupt transition from one electron reduction to four electron reduction, while oxygen reduction on GC gradually approaches four electron reduction as the potentials were driven more cathodic. The potential at which oxygen reduction initiates shows general agreement with the Nernst equation and the acid's tabulated aqueous pKa value, however at the extremely acidic end, a small deviation is observed. The second set of experiments in C4dMImTf solicited water as the proton donor for oxygen reduction in an approximation of the aqueous alkaline case. The water content was varied between extremely dry (<0.1 mol% H2O) and saturated (approximately 15.8 mol% H2O). As the water content increased so too did the extent of oxygen reduction eventually approach two electrons on both Pt and GC. However, additional water led to a linear increase in the Tafel slope under enhanced mass transport conditions up to the point of 10 mol% water. This inhibition of oxygen adsorption is the result of the interaction between superoxide and water and more specifically is proposed to be associated with decomposition of theC4dMIm + cation by hydroxide at the elevated temperatures required for the experiment. Oxygen reduction on both Pt and GC follows Nernstian behavior as the water content is increased. Separate mechanisms for oxygen reduction on Pt and GC are proposed based on the nature of the Nernstian response in these systems.

Advances in the analysis of biological samples using ionic liquids.

PubMed

Clark, Kevin D; Trujillo-Rodríguez, María J; Anderson, Jared L

2018-02-12

Ionic liquids are a class of solvents and materials that hold great promise in bioanalytical chemistry. Task-specific ionic liquids have recently been designed for the selective extraction, separation, and detection of proteins, peptides, nucleic acids, and other physiologically relevant analytes from complex biological samples. To facilitate rapid bioanalysis, ionic liquids have been integrated in miniaturized and automated procedures. Bioanalytical separations have also benefited from the modification of nonspecific magnetic materials with ionic liquids or the implementation of ionic liquids with inherent magnetic properties. Furthermore, the direct detection of the extracted molecules in the analytical instrument has been demonstrated with structurally tuned ionic liquids and magnetic ionic liquids, providing a significant advantage in the analysis of low-abundance analytes. This article gives an overview of these advances that involve the application of ionic liquids and derivatives in bioanalysis. Graphical abstract Ionic liquids, magnetic ionic liquids, and ionic liquid-based sorbents are increasing the speed, selectivity, and sensitivity in the analysis of biological samples.

Static gas-liquid interfacial direct current discharge plasmas using ionic liquid cathode

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaneko, T.; CREST/JST, Tokyo 102-0075; Baba, K.

Due to the unique properties of ionic liquids such as their extremely low vapor pressure and high heat capacity, we have succeeded in creating the static and stable gas (plasmas)-liquid (ionic liquids) interfacial field using a direct current discharge under a low gas pressure condition. It is clarified that the ionic liquid works as a nonmetal liquid electrode, and furthermore, a secondary electron emission coefficient of the ionic liquid is larger than that of conventional metal electrodes. The plasma potential structure of the gas-liquid interfacial region, and resultant interactions between the plasma and the ionic liquid are revealed by changingmore » a polarity of the electrode in the ionic liquid. By utilizing the ionic liquid as a cathode electrode, the positive ions in the plasma region are found to be irradiated to the ionic liquid. This ion irradiation causes physical and chemical reactions at the gas-liquid interfacial region without the vaporization of the ionic liquid.« less

Functionalized ionic liquids and their applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hariprakasha, Humcha Krishnamurthy; Rangan, Krishnaswamy Kasthuri; Sudarshan, Tirumalai Srinivas

2018-01-16

Disclosure of functionalized ionic liquids. Use of disclosed ionic liquids as solvent for carbon dioxide. Use of disclosed ionic liquids as flame retardant. Use of disclosed ionic liquids for coating fabric to obtain flame retardant fabric.

Fast Ignition and Sustained Combustion of Ionic Liquids

NASA Technical Reports Server (NTRS)

Joshi, Prakash B. (Inventor); Piper, Lawrence G. (Inventor); Oakes, David B. (Inventor); Sabourin, Justin L. (Inventor); Hicks, Adam J. (Inventor); Green, B. David (Inventor); Tsinberg, Anait (Inventor); Dokhan, Allan (Inventor)

2016-01-01

A catalyst free method of igniting an ionic liquid is provided. The method can include mixing a liquid hypergol with a HAN (Hydroxylammonium nitrate)-based ionic liquid to ignite the HAN-based ionic liquid in the absence of a catalyst. The HAN-based ionic liquid and the liquid hypergol can be injected into a combustion chamber. The HAN-based ionic liquid and the liquid hypergol can impinge upon a stagnation plate positioned at top portion of the combustion chamber.

Ionic liquids as novel solvents for ionic polymer transducers

NASA Astrophysics Data System (ADS)

Bennett, Matthew D.; Leo, Donald J.

2004-07-01

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 traditional problem of water evaporation in these devices. Another benefit of the use of ionic liquids in this way is the reduction or elimination of the characteristic back-relaxation common in water-solvated ionic polymer actuators. The results demonstrate that the viscosity of the ionic liquid and the degree to which the ionic liquid swells the membrane are the important physical parameters to consider. Five ionic liquids were studied, based on substituted pyrrolidinium, phosphonium, or imidazolium cations and fluoroanions. Of these five ionic liquids, transduction is demonstrated in three of them and the best results are obtained with 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ionic liquid. This substance has an electrochemical stability window of 4.1 V, a melting point of -10 °C, and a viscosity of 35-45 cP [19]. Results demonstrate that platinum-plated Nafion transducers solvated with this ionic liquid exhibit sensing and actuation responses and that these transducers are stable in air. Endurance testing of this sample reveals a decrease in the free strain of only 25 % after 250,000 actuation cycles in air.

Morphological and electromechanical characterization of ionic liquid/Nafion polymer composites

NASA Astrophysics Data System (ADS)

Bennett, Matthew; Leo, Donald

2005-05-01

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.

Porous ionic liquids: synthesis and application.

PubMed

Zhang, Shiguo; Dokko, Kaoru; Watanabe, Masayoshi

2015-07-15

Solidification of fluidic ionic liquids into porous materials yields porous ionic networks that combine the unique characteristics of ionic liquids with the common features of polymers and porous materials. This minireview reports the most recent advances in the design of porous ionic liquids. A summary of the synthesis of ordered and disordered porous ionic liquid-based nanoparticles or membranes with or without templates is provided, together with the new concept of room temperature porous ionic liquids. As a versatile platform for functional materials, porous ionic liquids have shown widespread applications in catalysis, adsorption, sensing, actuation, etc. This new research direction towards ionic liquids chemistry is still in its early stages but has great potential.

Competing Intramolecular vs. Intermolecular Hydrogen Bonds in Solution

PubMed Central

Nagy, Peter I.

2014-01-01

A hydrogen bond for a local-minimum-energy structure can be identified according to the definition of the International Union of Pure and Applied Chemistry (IUPAC recommendation 2011) or by finding a special bond critical point on the density map of the structure in the framework of the atoms-in-molecules theory. Nonetheless, a given structural conformation may be simply favored by electrostatic interactions. The present review surveys the in-solution competition of the conformations with intramolecular vs. intermolecular hydrogen bonds for different types of small organic molecules. In their most stable gas-phase structure, an intramolecular hydrogen bond is possible. In a protic solution, the intramolecular hydrogen bond may disrupt in favor of two solute-solvent intermolecular hydrogen bonds. The balance of the increased internal energy and the stabilizing effect of the solute-solvent interactions regulates the new conformer composition in the liquid phase. The review additionally considers the solvent effects on the stability of simple dimeric systems as revealed from molecular dynamics simulations or on the basis of the calculated potential of mean force curves. Finally, studies of the solvent effects on the type of the intermolecular hydrogen bond (neutral or ionic) in acid-base complexes have been surveyed. PMID:25353178

Enhanced Mass Defect Filtering To Simplify and Classify Complex Mixtures of Lignin Degradation Products.

PubMed

Dier, Tobias K F; Egele, Kerstin; Fossog, Verlaine; Hempelmann, Rolf; Volmer, Dietrich A

2016-01-19

High resolution mass spectrometry was utilized to study the highly complex product mixtures resulting from electrochemical breakdown of lignin. As most of the chemical structures of the degradation products were unknown, enhanced mass defect filtering techniques were implemented to simplify the characterization of the mixtures. It was shown that the implemented ionization techniques had a major impact on the range of detectable breakdown products, with atmospheric pressure photoionization in negative ionization mode providing the widest coverage in our experiments. Different modified Kendrick mass plots were used as a basis for mass defect filtering, where Kendrick mass defect and the mass defect of the lignin-specific guaiacol (C7H7O2) monomeric unit were utilized, readily allowing class assignments independent of the oligomeric state of the product. The enhanced mass defect filtering strategy therefore provided rapid characterization of the sample composition. In addition, the structural similarities between the compounds within a degradation sequence were determined by comparison to a tentatively identified product of this compound series. In general, our analyses revealed that primarily breakdown products with low oxygen content were formed under electrochemical conditions using protic ionic liquids as solvent for lignin.

Active chemisorption sites in functionalized ionic liquids for carbon capture.

PubMed

Cui, Guokai; Wang, Jianji; Zhang, Suojiang

2016-07-25

Development of novel technologies for the efficient and reversible capture of CO2 is highly desired. In the last decade, CO2 capture using ionic liquids has attracted intensive attention from both academia and industry, and has been recognized as a very promising technology. Recently, a new approach has been developed for highly efficient capture of CO2 by site-containing ionic liquids through chemical interaction. This perspective review focuses on the recent advances in the chemical absorption of CO2 using site-containing ionic liquids, such as amino-based ionic liquids, azolate ionic liquids, phenolate ionic liquids, dual-functionalized ionic liquids, pyridine-containing ionic liquids and so on. Other site-containing liquid absorbents such as amine-based solutions, switchable solvents, and functionalized ionic liquid-amine blends are also investigated. Strategies have been discussed for how to activate the existent reactive sites and develop novel reactive sites by physical and chemical methods to enhance CO2 absorption capacity and reduce absorption enthalpy. The carbon capture mechanisms of these site-containing liquid absorbents are also presented. Particular attention has been paid to the latest progress in CO2 capture in multiple-site interactions by amino-free anion-functionalized ionic liquids. In the last section, future directions and prospects for carbon capture by site-containing ionic liquids are outlined.

Nanoparticles in ionic liquids: interactions and organization.

PubMed

He, Zhiqi; Alexandridis, Paschalis

2015-07-28

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

[Advances of poly (ionic liquid) materials in separation science].

PubMed

Liu, Cuicui; Guo, Ting; Su, Rina; Gu, Yuchen; Deng, Qiliang

2015-11-01

Ionic liquids, as novel ionization reagents, possess beneficial characteristics including good solubility, conductivity, thermal stability, biocompatibility, low volatility and non-flammability. Ionic liquids are attracting a mass of attention of analytical chemists. Poly (ionic liquid) materials have common performances of ionic liquids and polymers, and have been successfully applied in separation science area. In this paper, we discuss the interaction mechanisms between the poly(ionic liquid) materials and analytes including hydrophobic/hydrophilic interactions, hydrogen bond, ion exchange, π-π stacking and electrostatic interactions, and summarize the application advances of the poly(ionic liquid) materials in solid phase extraction, chromatographic separation and capillary electrophoresis. At last, we describe the future prospect of poly(ionic liquid) materials.

Organosilica Membrane with Ionic Liquid Properties for Separation of Toluene/H₂ Mixture.

PubMed

Hirota, Yuichiro; Maeda, Yohei; Yamamoto, Yusuke; Miyamoto, Manabu; Nishiyama, Norikazu

2017-08-03

In this study, we present a new concept in chemically stabilized ionic liquid membranes: an ionic liquid organosilica (ILOS) membrane, which is an organosilica membrane with ionic liquid-like properties. A silylated ionic liquid was used as a precursor for synthesis. The permselectivity, permeation mechanism, and stability of the membrane in the H₂/toluene binary system were then compared with a supported ionic liquid membrane. The membrane showed a superior separation factor of toluene/H₂ (>17,000) in a binary mixture system based on a solution-diffusion mechanism with improved durability over the supported ionic liquid membrane.

Ionic Liquid-Doped Gel Polymer Electrolyte for Flexible Lithium-Ion Polymer Batteries

PubMed Central

Zhang, Ruisi; Chen, Yuanfen; Montazami, Reza

2015-01-01

Application of gel polymer electrolytes (GPE) in lithium-ion polymer batteries can address many shortcomings associated with liquid electrolyte lithium-ion batteries. Due to their physical structure, GPEs exhibit lower ion conductivity compared to their liquid counterparts. In this work, we have investigated and report improved ion conductivity in GPEs doped with ionic liquid. Samples containing ionic liquid at a variety of volume percentages (vol %) were characterized for their electrochemical and ionic properties. It is concluded that excess ionic liquid can damage internal structure of the batteries and result in unwanted electrochemical reactions; however, samples containing 40–50 vol % ionic liquid exhibit superior ionic properties and lower internal resistance compared to those containing less or more ionic liquids.

Ionic liquids in chemical engineering.

PubMed

Werner, Sebastian; Haumann, Marco; Wasserscheid, Peter

2010-01-01

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

Fluorescent probe studies of polarity and solvation within room temperature ionic liquids: a review.

PubMed

Pandey, Shubha; Baker, Sheila N; Pandey, Siddharth; Baker, Gary A

2012-09-01

Ionic liquids display an array of useful and sometimes unconventional, solvent features and have attracted considerable interest in the field of green chemistry for the potential they hold to significantly reduce environmental emissions. Some of these points have a bearing on the chemical reactivity of these systems and have also generated interest in the physical and theoretical aspects of solvation in ionic liquids. This review presents an introduction to the field of ionic liquids, followed by discussion of investigations into the solvation properties of neat ionic liquids or mixed systems including ionic liquids as a major or minor component. The ionic liquid based multicomponent systems discussed are composed of other solvents, other ionic liquids, carbon dioxide, surfactants or surfactant solutions. Although we clearly focus on fluorescence spectroscopy as a tool to illuminate ionic liquid systems, the issues discussed herein are of general relevance to discussions of polarity and solvent effects in ionic liquids. Transient solvation measurements carried out by means of time-resolved fluorescence measurements are particularly powerful for their ability to parameterize the kinetics of the solvation process in ionic liquids and are discussed as well.

Ionic Liquids and Relative Process Design

NASA Astrophysics Data System (ADS)

Zhang, S.; Lu, X.; Zhang, Y.; Zhou, Q.; Sun, J.; Han, L.; Yue, G.; Liu, X.; Cheng, W.; Li, S.

Ionic liquids have gained increasing attention in recent years due to their significant advantages, not only as alternative solvents but also as new materials and catalysts. Until now, most research work on ionic liquids has been at the laboratory or pilot scale. In view of the multifarious applications of ionic liquids, more new knowledge is needed and more systematic work on ionic liquids should be carried out deeply and broadly in order to meet the future needs of process design. For example, knowledge of the physicochemical properties is indispensable for the design of new ionic liquids and for the development of novel processes. The synthesis and application of ionic liquids are fundamental parts of engineering science, and the toxicity and environmental assessment of ionic liquids is critical importance for their large scale applications, especially for process design. These research aspects are closely correlated to the industrial applications of ionic liquids and to sustainable processes. However, material process design in the industrial applications of ionic liquids has hardly been implemented. Therefore, this chapter reviews several essential issues that are closely related to process design, such as the synthesis, structure-property relationships, important applications, and toxicity of ionic liquids.

Acidic Ionic Liquids.

PubMed

Amarasekara, Ananda S

2016-05-25

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

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

2015-12-08

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

Ionic Liquids Database- (ILThermo)

National Institute of Standards and Technology Data Gateway

SRD 147 NIST 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.

Ionic liquid and nanoparticle hybrid systems: Emerging applications.

PubMed

He, Zhiqi; Alexandridis, Paschalis

2017-06-01

Having novel electronic and optical properties that emanate from their nano-scale dimensions, nanoparticles are central to numerous applications. Ionic liquids can confer to nanoparticle chemical protection and physicochemical property enhancement through intermolecular interactions and can consequently improve the stability and reusability of nanoparticle for various operations. With an aim to combine the novel properties of nanoparticles and ionic liquids, different structures have been generated, based on a balance of several intermolecular interactions. Such ionic liquid and nanoparticle hybrids are showing great potential in diverse applications. In this review, we first introduce various types of ionic liquid and nanoparticle hybrids, including nanoparticle colloidal dispersions in ionic liquids, ionic liquid-grafted nanoparticles, and nanoparticle-stabilized ionic liquid-based emulsions. Such hybrid materials exhibit interesting synergisms. We then highlight representative applications of ionic liquid and nanoparticle hybrids in the catalysis, electrochemistry and separations fields. Such hybrids can attain better stability and higher efficiency under a broad range of conditions. Novel and enhanced performance can be achieved in these applications by combining desired properties of ionic liquids and of nanoparticles within an appropriate hybrid nanostructure. Copyright © 2016 Elsevier B.V. All rights reserved.

Recent progress of task-specific ionic liquids in chiral resolution and extraction of biological samples and metal ions.

PubMed

Wu, Datong; Cai, Pengfei; Zhao, Xiaoyong; Kong, Yong; Pan, Yuanjiang

2018-01-01

Ionic liquids have been functionalized for modern applications. The functional ionic liquids are also called task-specific ionic liquids. Various task-specific ionic liquids with certain groups have been constructed and exploited widely in the field of separation. To take advantage of their properties in separation science, task-specific ionic liquids are generally used in techniques such as liquid-liquid extraction, solid-phase extraction, gas chromatography, high-performance liquid chromatography, and capillary electrophoresis. This review mainly covers original research papers published in the last five years, and we will focus on task-specific ionic liquids as the chiral selectors in chiral resolution and as extractant or sensor for biological samples and metal ion purification. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Research on solar pumped liquid lasers

NASA Technical Reports Server (NTRS)

Cox, J. D.; Kurzweg, U. H.; Weinstein, N. H.; Schneider, R. T.

1985-01-01

A solar pumped liquid laser that can be scaled up to high power (10 mW CW) for space applications was developed. Liquid lasers have the advantage over gases in that they provide much higher lasant densities and thus high-power densities. Liquids also have advantages over solids in that they have much higher damage thresholds and are much cheaper to produce for large scale applications. Among the liquid laser media that are potential candidates for solar pumping, the POC13: Nd sup 3+:ZrC14 liquid was chosen for its high intrinsic efficiency and its relatively good stability against decomposition due to protic contamination. The development of a manufacturing procedure and performance testing of the laser, liquid and the development of an inexpensive large solar concentrator to pump the laser are examined.

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

PubMed

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

2014-12-01

A series of novel tetramethylguanidinium ionic liquids and hexaalkylguanidinium ionic liquids have been synthesized based on 1,1,3,3-tetramethylguanidine. The structures of the ionic liquids were confirmed by (1)H NMR spectroscopy and mass spectrometry. A green guanidinium ionic liquid based microwave-assisted extraction method has been developed with these guanidinium ionic liquids for the effective extraction of Praeruptorin A from Radix peucedani. After extraction, reversed-phase high-performance liquid chromatography with UV detection was employed for the analysis of Praeruptorin A. Several significant operating parameters were systematically optimized by single-factor and L9 (3(4)) orthogonal array experiments. The amount of Praeruptorin A extracted by [1,1,3,3-tetramethylguanidine]CH2CH(OH)COOH is the highest, reaching 11.05 ± 0.13 mg/g. Guanidinium ionic liquid based microwave-assisted extraction presents unique advantages in Praeruptorin A extraction compared with guanidinium ionic liquid based maceration extraction, guanidinium ionic liquid based heat reflux extraction and guanidinium ionic liquid based ultrasound-assisted extraction. The precision, stability, and repeatability of the process were investigated. The mechanisms of guanidinium ionic liquid based microwave-assisted extraction were researched by scanning electron microscopy and IR spectroscopy. All the results show that guanidinium ionic liquid based microwave-assisted extraction has a huge potential in the extraction of bioactive compounds from complex samples. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Influence of the ionic liquid/gas surface on ionic liquid chemistry.

PubMed

Lovelock, Kevin R J

2012-04-21

Applications such as gas storage, gas separation, NP synthesis and supported ionic liquid phase catalysis depend upon the interaction of different species with the ionic liquid/gas surface. Consequently, these applications cannot proceed to the full extent of their potential without a profound understanding of the surface structure and properties. As a whole, this perspective contains more questions than answers, which demonstrates the current state of the field. Throughout this perspective, crucial questions are posed and a roadmap is proposed to answer these questions. A critical analysis is made of the field of ionic liquid/gas surface structure and properties, and a number of design rules are mined. The effects of ionic additives on the ionic liquid/gas surface structure are presented. A possible driving force for surface formation is discussed that has, to the best of my knowledge, not been postulated in the literature to date. This driving force suggests that for systems composed solely of ions, the rules for surface formation of dilute electrolytes do not apply. The interaction of neutral additives with the ionic liquid/gas surface is discussed. Particular attention is focussed upon H(2)O and CO(2), vital additives for many applications of ionic liquids. Correlations between ionic liquid/gas surface structure and properties, ionic liquid surfaces plus additives, and ionic liquid applications are given. This journal is © the Owner Societies 2012

The electrode/ionic liquid interface: electric double layer and metal electrodeposition.

PubMed

Su, Yu-Zhuan; Fu, Yong-Chun; Wei, Yi-Min; Yan, Jia-Wei; Mao, Bing-Wei

2010-09-10

The last decade has witnessed remarkable advances in interfacial electrochemistry in room-temperature ionic liquids. Although the wide electrochemical window of ionic liquids is of primary concern in this new type of solvent for electrochemistry, the unusual bulk and interfacial properties brought about by the intrinsic strong interactions in the ionic liquid system also substantially influence the structure and processes at electrode/ionic liquid interfaces. Theoretical modeling and experimental characterizations have been indispensable in reaching a microscopic understanding of electrode/ionic liquid interfaces and in elucidating the physics behind new phenomena in ionic liquids. This Minireview describes the status of some aspects of interfacial electrochemistry in ionic liquids. Emphasis is placed on high-resolution and molecular-level characterization by scanning tunneling microscopy and vibrational spectroscopies of interfacial structures, and the initial stage of metal electrodeposition with application in surface nanostructuring.

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

NASA Astrophysics Data System (ADS)

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

2013-12-01

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

Dielectric study on mixtures of ionic liquids.

PubMed

Thoms, E; Sippel, P; Reuter, D; Weiß, M; Loidl, A; Krohns, S

2017-08-07

Ionic liquids are promising candidates for electrolytes in energy-storage systems. We demonstrate that mixing two ionic liquids allows to precisely tune their physical properties, like the dc conductivity. Moreover, these mixtures enable the gradual modification of the fragility parameter, which is believed to be a measure of the complexity of the energy landscape in supercooled liquids. The physical origin of this index is still under debate; therefore, mixing ionic liquids can provide further insights. From the chemical point of view, tuning ionic liquids via mixing is an easy and thus an economic way. For this study, we performed detailed investigations by broadband dielectric spectroscopy and differential scanning calorimetry on two mixing series of ionic liquids. One series combines an imidazole based with a pyridine based ionic liquid and the other two different anions in an imidazole based ionic liquid. The analysis of the glass-transition temperatures and the thorough evaluations of the measured dielectric permittivity and conductivity spectra reveal that the dynamics in mixtures of ionic liquids are well defined by the fractions of their parent compounds.

Impact of water dilution and cation tail length on ionic liquid characteristics: Interplay between polar and non-polar interactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hegde, Govind A.; Bharadwaj, Vivek S.; Kinsinger, Corey L.

2016-08-14

The recalcitrance of lignocellulosic biomass poses a major challenge that hinders the economical utilization of biomass for the production of biofuel, plastics, and chemicals. Ionic liquids have become a promising solvent that addresses many issues in both the pretreatment process and the hydrolysis of the glycosidic bond for the deconstruction of cellulosic materials. However, to make the use of ionic liquids economically viable, either the cost of ionic liquids must be reduced, or a less expensive solvent (e.g., water) may be added to reduce the overall amount of ionic liquid used in addition to reducing the viscosity of the binarymore » liquid mixture. In this work, we employ atomistic molecular dynamics simulations to investigate the impact of water dilution on the overall liquid structure and properties of three imidazolium based ionic liquids. It is found that ionic liquid-water mixtures exhibit characteristics that can be grouped into two distinct regions, which are a function of the ionic liquid concentration. The trends observed in each region are found to correlate with the ordering in the local structure of the ionic liquid that arises from the dynamic interactions between the ion pairs. Simulation results suggest that there is a high level of local ordering in the molecular structure at high concentrations of ionic liquids that is driven by the aggregation of the cationic tails and the anion-water interactions. It is found that as the concentration of ionic liquids in the binary mixture is decreased, there is a point at which the competing self and cross interaction energies between the ionic liquid and water shifts away from a cation-anion dominated regime, which results in a significant change in the mixture properties. This break point, which occurs around 75% w/w ionic liquids, corresponds to the point at which water molecules percolate into the ionic liquid network disrupting the ionic liquids’ nanostructure. It is observed that as the cationic alkyl tail length increases, the changes in the binary mixtures’ properties become more pronounced.« less

Biocatalytic transformations in ionic liquids.

PubMed

van Rantwijk, Fred; Madeira Lau, Rute; Sheldon, Roger A

2003-03-01

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 are often better than in traditional media. The unconventional solvent properties of ionic liquids have been exploited in biocatalyst recycling and product recovery schemes that are not feasible with traditional solvent systems.

Microscopic properties of ionic liquid/organic semiconductor interfaces revealed by molecular dynamics simulations.

PubMed

Yokota, Yasuyuki; Miyamoto, Hiroo; Imanishi, Akihito; Takeya, Jun; Inagaki, Kouji; Morikawa, Yoshitada; Fukui, Ken-Ichi

2018-05-09

Electric double-layer transistors based on ionic liquid/organic semiconductor interfaces have been extensively studied during the past decade because of their high carrier densities at low operation voltages. Microscopic structures and the dynamics of ionic liquids likely determine the device performance; however, knowledge of these is limited by a lack of appropriate experimental tools. In this study, we investigated ionic liquid/organic semiconductor interfaces using molecular dynamics to reveal the microscopic properties of ionic liquids. The organic semiconductors include pentacene, rubrene, fullerene, and 7,7,8,8-tetracyanoquinodimethane (TCNQ). While ionic liquids close to the substrate always form the specific layered structures, the surface properties of organic semiconductors drastically alter the ionic dynamics. Ionic liquids at the fullerene interface behave as a two-dimensional ionic crystal because of the energy gain derived from the favorable electrostatic interaction on the corrugated periodic substrate.

Direct current dielectrophoretic manipulation of the ionic liquid droplets in water.

PubMed

Zhao, Kai; Li, Dongqing

2018-07-13

The ionic liquids (ILs) as the environmentally benign solvents show great potentials in microemulsion carrier systems and have been widely used in the biochemical and pharmaceutical fields. In the work, the ionic liquid-in-water microemulsions were fabricated by using two kinds of hydrophobic ionic liquid, 1-Butyl-3-methylimidazolium hexafluorophosphate [Bmim][PF 6 ] and 1-Hexyl-3-methylimidazolium hexafluorophosphate [Hmim][PF 6 ] with Tween 20. The ionic liquid droplets in water experience the dielectrophoretic (DEP) forces induced by applying electrical field via a nano-orifice and a micron orifice on the opposite channel walls of a microchannel. The dielectrophoretic behaviors of the ionic liquid-in-water emulsion droplets were investigated under direct current (DC) electric field. The positive and negative DEP behaviors of the ionic liquid-in-water droplets varying with the electrical conductivity of the suspending medium were investigated and two kinds of the ionic liquid droplets of similar sizes were separated by their different DEP behaviors. In addition, the separation of the ionic liquid-in-water droplets by size was conducted. This paper, for the first time to our knowledge, presents the DC-DEP manipulation of the ionic liquid-in-water emulsion droplets by size and by type. This method provides a platform to manipulate the ionic liquid droplets individually. Copyright © 2018 Elsevier B.V. All rights reserved.

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

PubMed

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

2013-01-01

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

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

PubMed Central

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

2013-01-01

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

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

PubMed

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

2013-10-21

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

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

PubMed

Poole, Colin F

2004-05-28

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 the determination of gas-liquid partition coefficients and activity coefficients as well as thermodynamic constants derived from either of these parameters and their variation with temperature. The solvation parameter model can be used to define the contribution from individual intermolecular interactions to the gas-liquid partition coefficient. Application of chemometric procedures to a large database of system constants for ionic liquids indicates their unique solvent properties: low cohesion for ionic liquids with weakly associated ions compared with non-ionic liquids of similar polarity; greater hydrogen-bond basicity than typical polar non-ionic solvents; and a range of dipolarity/polarizability that encompasses the same range as occupied by the most polar non-ionic liquids. These properties can be crudely related to ion structures but further work is required to develop a comprehensive approach for the design of ionic liquids for specific applications. Data for liquid-liquid partition coefficients is scarce by comparison with gas-liquid partition coefficients. Preliminary studies indicate the possibility of using the solvation parameter model for interpretation of liquid-liquid partition coefficients determined by shake-flask procedures as well as the feasibility of using liquid-liquid chromatography for the convenient and rapid determination of liquid-liquid partition coefficients. Spectroscopic measurements of solvatochromic and fluorescent probe molecules in room temperature ionic liquids provide insights into solvent intermolecular interactions although interpretation of the different and generally uncorrelated "polarity" scales is sometimes ambiguous. All evidence points to the ionic liquids as a unique class of polar solvents suitable for technical development. In terms of designer solvents, however, further work is needed to fill the gaps in our knowledge of the relationship between ion structures and physicochemical properties.

Experimental and computational study on the properties of pure and water mixed 1-ethyl-3-methylimidazolium L-(+)-lactate ionic liquid.

PubMed

Aparicio, Santiago; Alcalde, Rafael; Atilhan, Mert

2010-05-06

Ionic liquids have attracted great attention, from both industry and academe, as alternative fluids for a large collection of applications. Although the term green is used frequently to describe ionic liquids in general, it is obvious that it cannot be applied to the huge quantity of possible ionic liquids, and thus, those with adequate environmental and technological profiles must be selected for further and deeper studies, from both basic science and applied approaches. In this work, 1-ethyl-3-methylimidazolium L-(+)-lactate ionic liquid is studied, because of its remarkable properties, through a wide-ranging approach considering thermophysical, spectroscopic, and computational tools, to gain a deeper insight into its complex liquid structure, both pure and mixed with water, thus implying the main factors that would control the technological applications that could be designed using this fluid. The reported results shows a strongly structured pure ionic liquid, in which hydrogen bonding, because of the hydroxyl group of the lactate anion, develops a remarkable role, together with Coulombic forces to determine the fluid's behavior. Upon mixing with water, the ionic liquid retains its structure up to very high dilution levels, with the effect of the ionic liquid on the water structure being very large, even for very low ionic liquid mole fractions. Thus, in water solution, the studied ionic liquid evolves from noninteracting ions solvated by water molecules toward large interacting structures with increasing ionic liquid content.

Dye-sensitized solar cells using ionic liquids as redox mediator

NASA Astrophysics Data System (ADS)

Denizalti, Serpil; Ali, Abdulrahman Khalaf; Ela, Çağatay; Ekmekci, Mesut; Erten-Ela, Sule

2018-01-01

In this research, the influence of ionic liquid on the conversion efficiency, incident photons to converted electrons (IPCE) and performance of fabricated solar cell was investigated using various ionic liquids. Ionic liquids with different substituents and ions were prepared and used as redox mediators in dye-sensitized solar cells (DSSCs). Ionic liquids were characterized 1H and 13C NMR spectra. We practically investigated the performance of ionic liquid salts were used as the mobile ions and found that the efficiencies of DSSCs were increased up to 40% comparing commercial electrolyte system. The ionic liquid compounds were incorporated in DSSCs to obtain an efficient charge transfer, solving the corrosion problem of platinum layer in counter electrode compared to commercial electrolyte.

Excimer Formation Dynamics of Dipyrenyldecane in Structurally Different Ionic Liquids.

PubMed

Yadav, Anita; Pandey, Siddharth

2017-12-07

Ionic liquids, being composed of ions alone, may offer alternative pathways for molecular aggregation. These pathways could be controlled by the chemical structure of the cation and the anion of the ionic liquids. Intramolecular excimer formation dynamics of a bifluorophoric probe, 1,3-bis(1-pyrenyl)decane [1Py(10)1Py], where the fluorophoric pyrene moieties are separated by a long decyl chain, is investigated in seven different ionic liquids in 10-90 °C temperature range. The long alkyl separator allows for ample interaction with the solubilizing milieu prior to the formation of the excimer. The ionic liquids are composed of two sets, one having four ionic liquids of 1-butyl-3-methylimidazolium cation ([bmim + ]) with different anions and the other having four ionic liquids of bis(trifluoromethylsulfonyl)imide anion ([Tf 2 N - ]) with different cations. The excimer-to-monomer emission intensity ratio (I E /I M ) is found to increase with increasing temperature in sigmoidal fashion. Chemical structure of the ionic liquid controls the excimer formation efficiency, as I E /I M values within ionic liquids with the same viscosities are found to be significantly different. The excited-state intensity decay kinetics of 1Py(10)1Py in ionic liquids do not adhere to a simplistic Birk's scheme, where only one excimer conformer forms after excitation. The apparent rate constants of excimer formation (k a ) in highly viscous ionic liquids are an order of magnitude lower than those reported in organic solvents. In general, the higher the viscosity of the ionic liquid, the more sensitive is the k a to the temperature with higher activation energy, E a . The trend in E a is found to be similar to that for activation energy of the viscous flow (E a,η ). Stokes-Einstein relationship is not followed in [bmim + ] ionic liquids; however, with the exception of [choline][Tf 2 N], it is found to be followed in [Tf 2 N - ] ionic liquids suggesting the cyclization dynamics of 1Py(10)1Py to be diffusion-controlled and to depend on the viscosity of the ionic liquid irrespective of the identity of the cation. The dependence of ionic liquid structure on cyclization dynamics to form intramolecular excimer is amply highlighted.

Microscopic characterization of tension wood cell walls of Japanese beech (Fagus crenata) treated with ionic liquids.

PubMed

Kanbayashi, Toru; Miyafuji, Hisashi

2016-09-01

Tension wood that is an abnormal part formed in angiosperms has been barely used for wood industry. In this study, to utilize the tension wood effectively by means of liquefaction using ionic liquid, we performed morphological and topochemical determination of the changes in tension wood of Japanese beech (Fagus crenata) during ionic liquid treatment at the cellular level using light microscopy, scanning electron microscopy and confocal Raman microscopy. Ionic liquid treatment induced cell wall swelling in tension wood. Changes in the tissue morphology treated with ionic liquids were different between normal wood and tension wood, moreover the types of ionic liquids. The ionic liquid 1-ethyl-3-methylimidazolium chloride liquefied gelatinous layers rapidly, whereas 1-ethylpyridinium bromide liquefied slowly but delignified selectively. These novel insights into the deconstruction behavior of tension wood cell walls during ionic liquid treatment provide better understanding of the liquefaction mechanism. The obtained knowledge will contribute to development of an effective chemical processing of tension wood using ionic liquids and lead to efficient use of wood resources. Copyright © 2016 Elsevier Ltd. All rights reserved.

Improving Cellulose Dissolution in Ionic Liquids by Tuning the Size of the Ions: Impact of the Length of the Alkyl Chains in Tetraalkylammonium Carboxylate.

PubMed

Meng, Xiangqian; Devemy, Julien; Verney, Vincent; Gautier, Arnaud; Husson, Pascale; Andanson, Jean-Michel

2017-04-22

Twenty ionic liquids based on tetraalkylammonium cations and carboxylate anions have been synthesized, characterized, and tested for cellulose dissolution. The amount of cellulose dissolved in these ionic liquids depends strongly on the size of the ions: from 0 to 22 wt % cellulose can be dissolved at 90 °C. The best ionic liquids are less viscous and ammonium carboxylate based ionic liquids can dissolve as much as imidazolium-based ones. The viscosity of an ionic liquid can be decreased by the addition of DMSO as a cosolvent. After the addition of cosolvent, similar amounts of cellulose per ions are reached for most ionic liquids. As observed by rheology, ionic liquids with the longest alkyl chains form a gel when a high amount of cellulose is dissolved; this drastically limits their potential. Molecular simulations and IR spectroscopy have also been used with the aim of understanding how molecular interactions differ between efficient and inefficient ionic liquids. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ionic liquids: Promising green solvents for lignocellulosic biomass utilization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoo, Chang Geun; Pu, Yunqiao; Ragauskas, Arthur J.

Ionic liquids are effective solvents/media for the utilization of lignocellulosic biomass. The unique properties of ionic liquids enable them to effectively dissolve and/or convert the biomass into various types of products. This review aims to cover the latest progress achieved in applications of ionic liquids on biomass conversion and analysis. Specifically, several recently developed approaches on how to overcome current challenges on the use of ionic liquids in the biomass conversion were highlighted. Here, recent studies addressing the potential applications of ionic liquids for the production of novel biomass-derived chemicals and materials were also discussed.

Ionic liquids: Promising green solvents for lignocellulosic biomass utilization

DOE PAGES

Yoo, Chang Geun; Pu, Yunqiao; Ragauskas, Arthur J.

2017-06-01

Ionic liquids are effective solvents/media for the utilization of lignocellulosic biomass. The unique properties of ionic liquids enable them to effectively dissolve and/or convert the biomass into various types of products. This review aims to cover the latest progress achieved in applications of ionic liquids on biomass conversion and analysis. Specifically, several recently developed approaches on how to overcome current challenges on the use of ionic liquids in the biomass conversion were highlighted. Here, recent studies addressing the potential applications of ionic liquids for the production of novel biomass-derived chemicals and materials were also discussed.

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

PubMed

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

2017-05-24

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

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lethesh, Kallidanthiyil Chellappan, E-mail: lethesh.chellappan@petronas.com.my; Wilfred, Cecilia Devi; Taha, M. F.

2014-10-24

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

Boundary layer charge dynamics in ionic liquid-ionic polymer transducers

NASA Astrophysics Data System (ADS)

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

2011-01-01

Ionic polymer transducers (IPTs), also known as ionic polymer-metal composites, are soft sensors and actuators which operate through a coupling of microscale 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 apply Nernst-Planck/Poisson theory to model charge transport in an ionic liquid IPT by considering a certain fraction of the ionic liquid ions as mobile charge carriers, a phenomenon which is unique to ionic liquid IPTs compared to their water-based counterparts. Numerical simulations are performed using the finite element method to examine how the introduction of another pair of mobile ions affects boundary layer charge dynamics, concentration, and charge density distributions in the electric double layer, and the overall charge transferred and current response of the IPT. Due to interactions with the Nafion ionomer, not all of the ionic liquid ions will function as mobile charge carriers; only a certain fraction will exist as "free" ions. The presence of mobile ionic liquid ions in the transducer will increase the overall charge transferred when a voltage is applied, and cause the current in the transducer to decay more slowly. The additional mobile ions also cause the ionic concentration profiles to exhibit a nonlinear dynamic response, characterized by nonmonotonic ionic concentration profiles in space and time. Although the presence of mobile ionic liquid ions increases the overall amount of charge transferred, this additional charge transfer occurs in a somewhat symmetric manner. Therefore, the additional charge transferred due to the ionic liquid ions does not greatly increase the net bending moment of the transducer; in fact, it is possible that ionic liquid ion movement actually decreases the observed bending response. This suggests that an optimal electromechanical conversion efficiency for bending actuation is achieved by using an ionic liquid where only a relatively small fraction of the ionic liquid ions exist as free ions. Conversely, if it is desired to increase the overall amount of charge transferred, an ionic liquid with a large fraction of free ions should be used. These theoretical considerations are found to be in good qualitative agreement with recent experimental results.

Ionic Liquids as Extraction Media for Metal Ions

NASA Astrophysics Data System (ADS)

Hirayama, Naoki

In solvent extraction separation of metal ions, recently, many researchers have investigated possible use of hydrophobic ionic liquids as extraction media instead of organic solvents. Ionic liquids are salts of liquid state around room temperature and can act not only as solvents but also as ion-exchangers. Therefore, the extraction mechanism of metal ions into ionic liquids is complicated. This review presents current overview and perspective on evaluation of nature of hydrophobic ionic liquids as extraction media for metal ions.

Research on solar pumped liquid lasers. Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cox, J.D.; Kurzweg, U.H.; Weinstein, N.H.

1985-04-01

A solar pumped liquid laser that can be scaled up to high power (10 mW CW) for space applications was developed. Liquid lasers have the advantage over gases in that they provide much higher lasant densities and thus high-power densities. Liquids also have advantages over solids in that they have much higher damage thresholds and are much cheaper to produce for large scale applications. Among the liquid laser media that are potential candidates for solar pumping, the POC13: Nd sup 3+:ZrCl4 liquid was chosen for its high intrinsic efficiency and its relatively good stability against decomposition due to protic contamination.more » The development of a manufacturing procedure and performance testing of the laser liquid and the development of an inexpensive large solar concentrator to pump the laser are examined.« less

Specialist gelator for ionic liquids.

PubMed

Hanabusa, Kenji; Fukui, Hiroaki; Suzuki, Masahiro; Shirai, Hirofusa

2005-11-08

Cyclo(l-beta-3,7-dimethyloctylasparaginyl-L-phenylalanyl) (1) and cyclo(L-beta-2-ethylhexylasparaginyl-L-phenylalanyl) (2), prepared from L-asparaginyl-L-phenylalanine methyl ester, have been found to be specialist gelators for ionic liquids. They can gel a wide variety of ionic liquids, including imizazolium, pyridinium, pyrazolidinium, piperidinium, morpholinium, and ammonium salts. The mean minimum gel concentrations (MGCs) necessary to make gels at 25 degrees C were determined for ionic liquids. The gel strength increased at a rate nearly proportional to the concentration of added gelator. The strength of the transparent gel of 1-butylpyridinium tetrafluoroborate ([C(4)py]BF(4)), prepared at a concentration of 60 g L(-1) (gelator 1/[C(4)py]BF(4)), was ca. 1500 g cm(-2). FT-IR spectroscopy indicated that a driving force for gelation was intermolecular hydrogen bonding between amides and that the phase transition from gel to liquid upon heating was brought about by the collapse of hydrogen bonding. The gels formed from ionic liquids were very thermally stable; no melting occurs up to 140 degrees C when the gels were prepared at a concentration of 70 g L(-1) (gelator/ionic liquid). The ionic conductivities of the gels were nearly the same as those of pure ionic liquids. The gelator had electrochemical stability and a wide electrochemical window. When the gels were prepared from ionic liquids containing propylene carbonate, the ionic conductivities of the resulting gels increased to levels rather higher than those of pure ionic liquids. The gelators also gelled ionic liquids containing supporting electrolytes.

Vibrational Spectroscopy of Ionic Liquids.

PubMed

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

2017-05-24

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

On the chemical stabilities of ionic liquids.

PubMed

Sowmiah, Subbiah; Srinivasadesikan, Venkatesan; Tseng, Ming-Chung; Chu, Yen-Ho

2009-09-25

Ionic liquids are novel solvents of interest as greener alternatives to conventional organic solvents aimed at facilitating sustainable chemistry. As a consequence of their unusual physical properties, reusability, and eco-friendly nature, ionic liquids have attracted the attention of organic chemists. Numerous reports have revealed that many catalysts and reagents were supported in the ionic liquid phase, resulting in enhanced reactivity and selectivity in various important reaction transformations. However, synthetic chemists cannot ignore the stability data and intermolecular interactions, or even reactions that are directly applicable to organic reactions in ionic liquids. It is becoming evident from the increasing number of reports on use of ionic liquids as solvents, catalysts, and reagents in organic synthesis that they are not totally inert under many reaction conditions. While in some cases, their unexpected reactivity has proven fortuitously advantageous in others is has been a problem, it is imperative that when selecting an ionic liquid for a particular synthetic application, attention be paid to its compatibility with the reaction conditions. Even though, more than 200 room temperature ionic liquids are known, only a few reports have commented their effects on reaction mechanisms or rate/stability. Therefore, rather than attempting to give a comprehensive overview of ionic liquid chemistry, this review focuses on the non-innocent nature of ionic liquids, with a decided emphasis to clearly illuminate the ability of ionic liquids to affect the mechanistic aspects of some organic reactions thereby affecting and promoting the yield and selectivity.

Ionic liquid containing hydroxamate and N-alkyl sulfamate ions

DOEpatents

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

2016-03-15

Embodiments of the invention are related to ionic liquids and more specifically to ionic liquids used in electrochemical metal-air cells in which the ionic liquid includes a cation and an anion selected from hydroxamate and/or N-alkyl sulfamate anions.

Electrical, structural, thermal and electrochemical properties of corn starch-based biopolymer electrolytes.

PubMed

Liew, Chiam-Wen; Ramesh, S

2015-06-25

Biopolymer electrolytes containing corn starch, lithium hexafluorophosphate (LiPF6) and ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate (BmImPF6) are prepared by solution casting technique. Temperature dependence-ionic conductivity studies reveal Vogel-Tamman-Fulcher (VTF) relationship which is associated with free volume theory. Ionic liquid-based biopolymer electrolytes show lower glass transition temperature (Tg) than ionic liquid-free biopolymer electrolyte. X-ray diffraction (XRD) studies demonstrate higher amorphous region of ionic liquid-added biopolymer electrolytes. In addition, the potential stability window of the biopolymer electrolyte becomes wider and stable up to 2.9V. Conclusively, the fabricated electric double layer capacitor (EDLC) shows improved electrochemical performance upon addition of ionic liquid into the biopolymer electrolyte. The specific capacitance of EDLC based on ionic liquid-added polymer electrolyte is relatively higher than that of ionic liquid-free polymer electrolyte as depicted in cyclic voltammogram. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

PubMed

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

2015-01-01

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

Mixtures of the 1-ethyl-3-methylimidazolium acetate ionic liquid with different inorganic salts: insights into their interactions.

PubMed

Oliveira, Filipe S; Cabrita, Eurico J; Todorovic, Smilja; Bernardes, Carlos E S; Lopes, José N Canongia; Hodgson, Jennifer L; MacFarlane, Douglas R; Rebelo, Luís P N; Marrucho, Isabel M

2016-01-28

In this work, we explore the interactions between the ionic liquid 1-ethyl-3-methylimidazolim acetate and different inorganic salts belonging to two different cation families, those based on ammonium and others based on sodium. NMR and Raman spectroscopy are used to screen for changes in the molecular environment of the ions in the ionic liquid + inorganic salt mixtures as compared to pure ionic liquid. The ion self-diffusion coefficients are determined from NMR data, allowing the discussion of the ionicity values of the ionic liquid + inorganic salt mixtures calculated using different methods. Our data reveal that preferential interactions are established between the ionic liquid and ammonium-based salts, as opposed to sodium-based salts. Computational calculations show the formation of aggregates between the ionic liquid and the inorganic salt, which is consistent with the spectroscopic data, and indicate that the acetate anion of the ionic liquid establishes preferential interactions with the ammonium cation of the inorganic salts, leaving the imidazolium cation less engaged in the media.

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

PubMed Central

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

2014-01-01

The challenge in preparation of ionic liquids containing a strong alkaline anion is to identify a suitable cation which can tolerate the harsh conditions induced by the anion. In this study, a commercial quaternary ammonium compound (quat) benzalkonium [ADBA] (alkyldimethylbenzylammonium) was used as a cation in the synthesis of different alkaline ionic liquids. In fact, the precursor, benzalkonium chloride, is a mixture of alkyldimethylbenzylammonium chlorides of various alkyl chain lengths and is commonly used in the formulation of various antiseptic products. The prepared ionic liquids were utilized as Supported Ionic Liquid Catalysts (SILCAs). Typically, a SILCA contains metal nanoparticles, enzymes, or metal complexes in an ionic liquid layer which is immobilized on a solid carrier material such as an active carbon cloth (ACC). The catalysts were applied in the selective hydrogenation of citral to citronellal which is an important perfumery chemical. Interestingly, 70% molar yield toward citronellal was achieved over a catalyst containing the alkaline ionic liquid benzalkonium methoxide. PMID:24790972

Electrolyte compositions for lithium ion batteries

DOEpatents

Sun, Xiao-Guang; Dai, Sheng; Liao, Chen

2016-03-29

The invention is directed in a first aspect to an ionic liquid of the general formula Y.sup.+Z.sup.-, wherein Y.sup.+ is a positively-charged component of the ionic liquid and Z.sup.- is a negatively-charged component of the ionic liquid, wherein Z.sup.- is a boron-containing anion of the following formula: ##STR00001## The invention is also directed to electrolyte compositions in which the boron-containing ionic liquid Y.sup.+Z.sup.- is incorporated into a lithium ion battery electrolyte, with or without admixture with another ionic liquid Y.sup.+X.sup.- and/or non-ionic solvent and/or non-ionic solvent additive.

Proteins in Ionic Liquids: Current Status of Experiments and Simulations.

PubMed

Schröder, Christian

2017-04-01

In the last two decades, while searching for interesting applications of ionic liquids as potent solvents, their solvation properties and their general impact on biomolecules, and in particular on proteins, gained interest. It turned out that ionic liquids are excellent solvents for protein refolding and crystallization. Biomolecules showed increased solubilities and stabilities, both operational and thermal, in ionic liquids, which also seem to prevent self-aggregation during solubilization. Biomolecules can be immobilized, e.g. in highly viscous ionic liquids, for particular biochemical processes and can be designed to some extent by the proper choice of the ionic liquid cations and anions, which can be characterized by the Hofmeister series.

Microcontact Printing of Thiol-Functionalized Ionic Liquid Microarrays for "Membrane-less" and "Spill-less" Gas Sensors.

PubMed

Gondosiswanto, Richard; Gunawan, Christian A; Hibbert, David B; Harper, Jason B; Zhao, Chuan

2016-11-16

Lab-on-a-chip systems have gained significant interest for both chemical synthesis and assays at the micro-to-nanoscale with a unique set of benefits. However, solvent volatility represents one of the major hurdles to the reliability and reproducibility of the lab-on-a-chip devices for large-scale applications. Here we demonstrate a strategy of combining nonvolatile and functionalized ionic liquids with microcontact printing for fabrication of "wall-less" microreactors and microfluidics with high reproducibility and high throughput. A range of thiol-functionalized ionic liquids have been synthesized and used as inks for microcontact printing of ionic liquid microdroplet arrays onto gold chips. The covalent bonds formed between the thiol-functionalized ionic liquids and the gold substrate offer enhanced stability of the ionic liquid microdroplets, compared to conventional nonfunctionalized ionic liquids, and these microdroplets remain stable in a range of nonpolar and polar solvents, including water. We further demonstrate the use of these open ionic liquid microarrays for fabrication of "membrane-less" and "spill-less" gas sensors with enhanced reproducibility and robustness. Ionic-liquid-based microarray and microfluidics fabricated using the described microcontact printing may provide a versatile platform for a diverse number of applications at scale.

Transferable Coarse-Grained Models for Ionic Liquids.

PubMed

Wang, Yanting; Feng, Shulu; Voth, Gregory A

2009-04-14

The effective force coarse-graining (EF-CG) method was applied to the imidazolium-based nitrate ionic liquids with various alkyl side-chain lengths. The nonbonded EF-CG forces for the ionic liquid with a short side chain were extended to generate the nonbonded forces for the ionic liquids with longer side chains. The EF-CG force fields for the ionic liquids exhibit very good transferability between different systems at various temperatures and are suitable for investigating the mesoscopic structural properties of this class of ionic liquids. The good additivity and ease of manipulation of the EF-CG force fields can allow for an inverse design methodology of ionic liquids at the coarse-grained level. With the EF-CG force field, the molecular dynamics (MD) simulation at a very large scale has been performed to check the significance of finite size effects on the structural properties. From these MD simulation results, it can be concluded that the finite size effect on the phenomenon of ionic liquid spatial heterogeneity (Wang, Y.; Voth, G. A. J. Am. Chem. Soc. 2005, 127, 12192) is small and that this phenomenon is indeed a nanostructural behavior which leads to the experimentally observed mesoscopic heterogeneous structure of ionic liquids.

Synthesis of electroactive ionic liquids for flow battery applications

DOEpatents

Anderson, Travis Mark; Ingersoll, David; Staiger, Chad; Pratt, Harry

2015-09-01

The present disclosure is directed to synthesizing metal ionic liquids with transition metal coordination cations, where such metal ionic liquids can be used in a flow battery. A cation of a metal ionic liquid includes a transition metal and a ligand coordinated to the transition metal.

Spontaneous Ionic Polarization in Ammonia-Based Ionic Liquid [Spontaneous Ionic Polarization in Ionic Liquid

DOE PAGES

Kim, Ki-jeong; Yuan, Hongtao; Jang, Hoyoung; ...

2018-05-24

Ionic liquids and gels have attracted attention for a variety of energy storage applications, as well as for high performance electrolytes for batteries and super-capacitors. Although the electronic structure of ionic electrolytes in these applications is of practical importance for device design and improved performance, the understanding of the electronic structure of ionic liquids and gels is still at an early stage. Here we report soft x-ray spectroscopic measurements of the surface electronic structure of a representative ammonia-based ionic gel (DEME-TFSI with PSPMMA- PS copolymer). We observe that near the outermost surface, the area of the anion peak (1s Nmore » - core level in TFSI) is relatively larger than that of the cation peak (N + in DEME). This spontaneous ionic polarization of the electrolyte surface, which is absent for the pure ionic liquid without copolymer, can be directly tuned by the copolymer content in the ionic gel, and further results in a modulation in work function. Finally, these results shed new light on the control of surface electronic properties of ionic electrolytes, as well as a difference between their implementation in ionic liquids and gels.« less

Spontaneous Ionic Polarization in Ammonia-Based Ionic Liquid [Spontaneous Ionic Polarization in Ionic Liquid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Ki-jeong; Yuan, Hongtao; Jang, Hoyoung

Ionic liquids and gels have attracted attention for a variety of energy storage applications, as well as for high performance electrolytes for batteries and super-capacitors. Although the electronic structure of ionic electrolytes in these applications is of practical importance for device design and improved performance, the understanding of the electronic structure of ionic liquids and gels is still at an early stage. Here we report soft x-ray spectroscopic measurements of the surface electronic structure of a representative ammonia-based ionic gel (DEME-TFSI with PSPMMA- PS copolymer). We observe that near the outermost surface, the area of the anion peak (1s Nmore » - core level in TFSI) is relatively larger than that of the cation peak (N + in DEME). This spontaneous ionic polarization of the electrolyte surface, which is absent for the pure ionic liquid without copolymer, can be directly tuned by the copolymer content in the ionic gel, and further results in a modulation in work function. Finally, these results shed new light on the control of surface electronic properties of ionic electrolytes, as well as a difference between their implementation in ionic liquids and gels.« less

Electrochemically stable electrolytes

DOEpatents

Angell, Charles Austen; Zhang, Sheng-Shui; Xu, Kang

1999-01-01

This invention relates generally to inorganic ionic liquids which function as electrolytes and do not crystallize at ambient temperature. More specifically, this invention is directed to quasi-salt inorganic ionic liquids which comprise the reaction product of a strong Lewis acid with an inorganic halide-donating molecule. This invention is further directed to quasi-salt inorganic ionic liquid mixtures which comprise combinations of electrolyte additives and quasi-salt inorganic ionic liquids. These quasi-salt inorganic ionic liquid mixtures are useful electrolytes.

Electrochemically stable electrolytes

DOEpatents

Angell, C.A.; Zhang, S.S.; Xu, K.

1999-01-05

This invention relates generally to inorganic ionic liquids which function as electrolytes and do not crystallize at ambient temperature. More specifically, this invention is directed to quasi-salt inorganic ionic liquids which comprise the reaction product of a strong Lewis acid with an inorganic halide-donating molecule. This invention is further directed to quasi-salt inorganic ionic liquid mixtures which comprise combinations of electrolyte additives and quasi-salt inorganic ionic liquids. These quasi-salt inorganic ionic liquid mixtures are useful electrolytes. 16 figs.

Thermal Decomposition Mechanism of 1-ethyl-3-methylimidazolium Bromide Ionic Liquid (Preprint)

DTIC Science & Technology

2011-09-14

TetraethylammoniumTrifluoromentanesulfonate Ionic Liquid and Neutralized Nafion 117 for High-Temperature Fuel Cells J. Am. Chem. Soc. 2010, 132, 2183-2195. (7) Kim, S. Y.; Kim, S...bromide 5b. GRANT NUMBER ionic liquid (Preprint) 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Steven D. Chambreau, Jerry A. Boatz, Ghanshyam L. Vaaghjiani...In order to better understand the volatilization process for ionic liquids , the vapor evolved from heating the ionic liquid 1-ethyl-3

Nanoparticle enhanced ionic liquid heat transfer fluids

DOEpatents

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

2014-08-12

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

Ionic liquids as a reaction medium for lipase-catalyzed methanolysis of sunflower oil.

PubMed

Sunitha, S; Kanjilal, S; Reddy, P S; Prasad, R B N

2007-12-01

Ionic liquids, 1-butyl-3-methyl imidazolium hexafluorophosphate ([BMIm][PF(6)]) and 1-ethyl-3-methyl imidazolium hexafluorophosphate ([EMIm][PF(6)]), were used for the methanolysis of sunflower oil using Candida antarctica lipase (Novozyme 435) and gave yields of fatty acid methyl esters at 98-99% within 10 h. The optimum conditions of methanolysis in hydrophobic ionic liquids are 2% (w/w) lipase, 1:1 (w/w) oil/ionic liquid and 1:8 (mol/mol) oil/methanol at 58-60 degrees C. Methanolysis using hydrophilic ionic liquids, 3-methyl imidazolium tetrafluoroborate ([HMIm][BF(4)]) and 1-butyl-3-methyl imidazolium tetrafluoroborate ([BMIm][BF(4)]), gave very poor yields. A hydrophobic ionic liquid thus protects the lipase from methanol. Recovered ionic liquids and lipase were used for four successive reaction cycles without any significant loss of activity.

Ionic Liquids as Electrolytes for Electrochemical Double-Layer Capacitors: Structures that Optimize Specific Energy.

PubMed

Mousavi, Maral P S; Wilson, Benjamin E; Kashefolgheta, Sadra; Anderson, Evan L; He, Siyao; Bühlmann, Philippe; Stein, Andreas

2016-02-10

Key parameters that influence the specific energy of electrochemical double-layer capacitors (EDLCs) are the double-layer capacitance and the operating potential of the cell. The operating potential of the cell is generally limited by the electrochemical window of the electrolyte solution, that is, the range of applied voltages within which the electrolyte or solvent is not reduced or oxidized. Ionic liquids are of interest as electrolytes for EDLCs because they offer relatively wide potential windows. Here, we provide a systematic study of the influence of the physical properties of ionic liquid electrolytes on the electrochemical stability and electrochemical performance (double-layer capacitance, specific energy) of EDLCs that employ a mesoporous carbon model electrode with uniform, highly interconnected mesopores (3DOm carbon). Several ionic liquids with structurally diverse anions (tetrafluoroborate, trifluoromethanesulfonate, trifluoromethanesulfonimide) and cations (imidazolium, ammonium, pyridinium, piperidinium, and pyrrolidinium) were investigated. We show that the cation size has a significant effect on the electrolyte viscosity and conductivity, as well as the capacitance of EDLCs. Imidazolium- and pyridinium-based ionic liquids provide the highest cell capacitance, and ammonium-based ionic liquids offer potential windows much larger than imidazolium and pyridinium ionic liquids. Increasing the chain length of the alkyl substituents in 1-alkyl-3-methylimidazolium trifluoromethanesulfonimide does not widen the potential window of the ionic liquid. We identified the ionic liquids that maximize the specific energies of EDLCs through the combined effects of their potential windows and the double-layer capacitance. The highest specific energies are obtained with ionic liquid electrolytes that possess moderate electrochemical stability, small ionic volumes, low viscosity, and hence high conductivity, the best performing ionic liquid tested being 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide.

Ionic liquid electrolytes for dye-sensitized solar cells.

PubMed

Gorlov, Mikhail; Kloo, Lars

2008-05-28

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

Recent development of ionic liquid stationary phases for liquid chromatography.

PubMed

Shi, Xianzhe; Qiao, Lizhen; Xu, Guowang

2015-11-13

Based on their particular physicochemical characteristics, ionic liquids have been widely applied in many fields of analytical chemistry. Many types of ionic liquids were immobilized on a support like silica or monolith as stationary phases for liquid chromatography. Moreover, different approaches were developed to bond covalently ionic liquids onto the supporting materials. The obtained ionic liquid stationary phases show multi-mode mechanism including hydrophobic, hydrophilic, hydrogen bond, anion exchange, π-π, and dipole-dipole interactions. Therefore, they could be used in different chromatographic modes including ion-exchange, RPLC, NPLC and HILIC to separate various classes of compounds. This review mainly summarizes the immobilized patterns and types of ionic liquid stationary phases, their retention mechanisms and applications in the recent five years. Copyright © 2015 Elsevier B.V. All rights reserved.

Fast Conversion of Ionic Liquids and Poly(Ionic Liquid)s into Porous Nitrogen-Doped Carbons in Air

PubMed Central

Men, Yongjun; Ambrogi, Martina; Han, Baohang; Yuan, Jiayin

2016-01-01

Ionic liquids and poly(ionic liquid)s have been successfully converted into nitrogen-doped porous carbons with tunable surface area up to 1200 m2/g at high temperatures in air. Compared to conventional carbonization process conducted under inert gas to produce nitrogen-doped carbons, the new production method was completed in a rather shorter time without noble gas protection. PMID:27070588

Fast Conversion of Ionic Liquids and Poly(Ionic Liquid)s into Porous Nitrogen-Doped Carbons in Air.

PubMed

Men, Yongjun; Ambrogi, Martina; Han, Baohang; Yuan, Jiayin

2016-04-08

Ionic liquids and poly(ionic liquid)s have been successfully converted into nitrogen-doped porous carbons with tunable surface area up to 1200 m²/g at high temperatures in air. Compared to conventional carbonization process conducted under inert gas to produce nitrogen-doped carbons, the new production method was completed in a rather shorter time without noble gas protection.

Ionic-Liquid-Infused Nanostructures as Repellent Surfaces.

PubMed

Galvan, Yaraset; Phillips, Katherine R; Haumann, Marco; Wasserscheid, Peter; Zarraga, Ramon; Vogel, Nicolas

2018-06-12

In order to prepare lubricant-infused repellent coatings on silica nanostructures using low vapor pressure ionic liquids as lubricants, we study the wetting behavior of a set of imidazolium-based ionic liquids with different alkyl side chains as a function of the applied surface functionalities. We take advantage of the structural color of inverse opals prepared from a colloidal coassembly technique to study the infiltration of ionic liquids into these nanoporous structures. We find that the more hydrophobic ionic liquids with butyl and hexyl side chains can completely infiltrate inverse opals functionalized with mixed self-assembled monolayers composed of imidazole groups and aliphatic hydrocarbon chains, which we introduce via silane chemistry. These molecular species reflect the chemical nature of the ionic liquid, thereby increasing the affinity between the liquid and solid surface. The mixed surface chemistry provides sufficiently small contact angles with the ionic liquid to infiltrate the nanopores while maximizing the contact angle with water. As a result, the mixed monolayers enable the design of a stable ionic liquid/solid interface that is able to repel water as a test liquid. Our results underline the importance of matching chemical affinities to predict and control the wetting behavior in complex, multiphase systems.

Application of Ionic Liquids in Amperometric Gas Sensors.

PubMed

Gębicki, Jacek; Kloskowski, Adam; Chrzanowski, Wojciech; Stepnowski, Piotr; Namiesnik, Jacek

2016-01-01

This article presents an analysis of available literature data on metrological parameters of the amperometric gas sensors containing ionic liquids as an electrolyte. Four mechanism types of signal generation in amperometric sensors with ionic liquid are described. Moreover, this article describes the influence of selected physico-chemical properties of the ionic liquids on the metrological parameters of these sensors. Some metrological parameters are also compared for amperometric sensors with GDE and SPE electrodes and with ionic liquids for selected analytes.

Generation and detection of the cyclohexadienyl radical in phosphonium ionic liquids.

PubMed

Lauzon, J M; Arseneau, D J; Brodovitch, J C; Clyburne, J A C; Cormier, P; McCollum, B; Ghandi, K

2008-10-21

The formation of the cyclohexadienyl radical, C(6)H(6)Mu, in ionic and molecular solvents has been compared. This is the first time that a muoniated free radical is reported in an ionic liquid. In marked contrast to molecular liquids, free radical generation in ionic liquids is significantly enhanced. Comparison of the hyperfine interactions in the ionic liquid and in molecular solvents and with theoretical calculations, suggests significant and unforeseen solvent interaction with the cyclohexadienyl radical.

The effect of varying the anion of an ionic liquid on the solvent effects on a nucleophilic aromatic substitution reaction.

PubMed

Hawker, Rebecca R; Haines, Ronald S; Harper, Jason B

2018-05-09

A variety of ionic liquids, each containing the same cation but a different anion, were examined as solvents for a nucleophilic aromatic substitution reaction. Varying the proportion of ionic liquid was found to increase the rate constant as the mole fraction of ionic liquid increased demonstrating that the reaction outcome could be controlled through varying the ionic liquid. The solvent effects were correlated with the hydrogen bond accepting ability (β) of the ionic liquid anion allowing for qualitative prediction of the effect of changing this component of the solute. To determine the microscopic origins of the solvent effects, activation parameters were determined through temperature-dependent kinetic analyses and shown to be consistent with previous studies. With the knowledge of the microscopic interactions in solution, an ionic liquid was rationally chosen to maximise rate enhancement demonstrating that an ionic solvent can be selected to control reaction outcome for this reaction type.

Ionic liquids for addressing unmet needs in healthcare

PubMed Central

Agatemor, Christian; Ibsen, Kelly N.; Tanner, Eden E. L.

2018-01-01

Abstract Advances in the field of ionic liquids have opened new applications beyond their traditional use as solvents into other fields especially healthcare. The broad chemical space, rich with structurally diverse ions, and coupled with the flexibility to form complementary ion pairs enables task‐specific optimization at the molecular level to design ionic liquids for envisioned functions. Consequently, ionic liquids now are tailored as innovative solutions to address many problems in medicine. To date, ionic liquids have been designed to promote dissolution of poorly soluble drugs and disrupt physiological barriers to transport drugs to targeted sites. Also, their antimicrobial activity has been demonstrated and could be exploited to prevent and treat infectious diseases. Metal‐containing ionic liquids have also been designed and offer unique features due to incorporation of metals. Here, we review application‐driven investigations of ionic liquids in medicine with respect to current status and future potential. PMID:29376130

Ionic liquid-based materials: a platform to design engineered CO2 separation membranes.

PubMed

Tomé, Liliana C; Marrucho, Isabel M

2016-05-21

During the past decade, significant advances in ionic liquid-based materials for the development of CO2 separation membranes have been accomplished. This review presents a perspective on different strategies that use ionic liquid-based materials as a unique tuneable platform to design task-specific advanced materials for CO2 separation membranes. Based on compilation and analysis of the data hitherto reported, we provide a judicious assessment of the CO2 separation efficiency of different membranes, and highlight breakthroughs and key challenges in this field. In particular, configurations such as supported ionic liquid membranes, polymer/ionic liquid composite membranes, gelled ionic liquid membranes and poly(ionic liquid)-based membranes are detailed, discussed and evaluated in terms of their efficiency, which is attributed to their chemical and structural features. Finally, an integrated perspective on technology, economy and sustainability is provided.

Dissolution and fractionation of nut shells in ionic liquids.

PubMed

Carneiro, Aristides P; Rodríguez, Oscar; Macedo, Eugénia A

2017-03-01

The aim of this work was to study the dissolution of raw peanut and chestnut shells in ionic liquids. Dissolution of raw biomass up to 7wt% was achieved under optimized operatory conditions. Quantification of polysaccharides dissolved through quantitative 13 Cq NMR revealed extractions of the cellulosic material to ionic liquids as high as 87%. Regeneration experiments using an antisolvent mixture allowed to recover the cellulosic material and the ionic liquid. The overall mass balance presented very low loss rates (<8%), recoveries of 75% and 95% of cellulosic material from peanut and chestnut shells, respectively, and the recovery of more than 95% of the ionic liquid in both cases. These results show the high potential of using nut shells and ionic liquids for biorefining purposes. Moreover, high recovery of ionic liquids favors the process from an economical point of view. Copyright © 2016 Elsevier Ltd. All rights reserved.

Incorporation of ionic liquid into porous polymer monoliths to enhance the separation of small molecules in reversed-phase high-performance liquid chromatography.

PubMed

Wang, Jiafei; Bai, Ligai; Wei, Zhen; Qin, Junxiao; Ma, Yamin; Liu, Haiyan

2015-06-01

An ionic liquid was incorporated into the porous polymer monoliths to afford stationary phases with enhanced chromatographic performance for small molecules in reversed-phase high-performance liquid chromatography. The effect of the ionic liquid in the polymerization mixture on the performance of the monoliths was studied in detail. While monoliths without ionic liquid exhibited poor resolution and low efficiency, the addition of ionic liquid to the polymerization mixture provides highly increased resolution and high efficiency. The chromatographic performances of the monoliths were demonstrated by the separations of various small molecules including aromatic hydrocarbons, isomers, and homologues using a binary polar mobile phase. The present column efficiency reached 27 000 plates/m, which showed that the ionic liquid monoliths are alternative stationary phases in the separation of small molecules by high-performance liquid chromatography. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Poly(1-Vinyl-1,2,4-triazolium) Poly(Ionic Liquid)s: Synthesis and the Unique Behavior in Loading Metal Ions.

PubMed

Zhang, Weiyi; Yuan, Jiayin

2016-07-01

Herein, the synthesis of a series of poly(4-alkyl-1-vinyl-1,2,4-triazolium) poly(ionic liquid)s is reported either via straightforward free radical polymerization of their corresponding ionic liquid monomers or via anion metathesis of the polymer precursors bearing halide as counter anion. The ionic liquid monomers are first prepared via N-alkylation reaction of commercially available 1-vinyl-1,2,4-triazole with alkyl iodides, followed by anion metathesis with targeted fluorinated anions. The thermal properties and solubilities of these poly(ionic liquid)s have been systematically investigated. Interestingly, it is found that the poly(4-ethyl-1-vinyl-1,2,4-triazolium) poly(ionic liquid) exhibited an improved loading capacity of transition metal ions in comparison with its imidazolium counterpart. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Catalytic asymmetric dihydroxylation of olefins using a recoverable and reusable OsO(4)2- in ionic liquid [bmim][PF6].

PubMed

Branco, Luís C; Afonso, Carlos A M

2002-12-21

The use of the solvent systems water/ionic liquid or water/ionic liquid/tert-butanol provides a recoverable, reusable, robust and simple system for the asymmetric dihydroxylation of olefins, based on the immobilization of the osmium-ligand catalyst in the ionic liquid phase.

Preparation of magnetic chitosan and graphene oxide-functional guanidinium ionic liquid composite for the solid-phase extraction of protein.

PubMed

Ding, Xueqin; Wang, Yuzhi; Wang, Ying; Pan, Qi; Chen, Jing; Huang, Yanhua; Xu, Kaijia

2015-02-25

A series of novel cationic functional hexaalkylguanidinium ionic liquids and anionic functional tetraalkylguanidinium ionic liquids have been synthesized, and then magnetic chitosan graphene oxide (MCGO) composite has been prepared and coated with these functional guanidinium ionic liquids to extract protein by magnetic solid-phase extraction. MCGO-functional guanidinium ionic liquid has been characterized by vibrating sample magnetometer, field emission scanning electron microscopy, X-ray diffraction spectrometer and Fourier transform infrared spectrometer. After extraction, the concentrations of protein were determined by measuring the absorbance at 278 nm using an ultra violet visible spectrophotometer. The advantages of MCGO-functional guanidinium ionic liquid in protein extraction were compared with magnetic chitosan, graphene oxide, MCGO and MCGO-ordinary imidazolium ionic liquid. The proposed method has been applied to extract trypsin, lysozyme, ovalbumin and bovine serum albumin. A comprehensive study of the adsorption conditions such as the concentration of protein, the amount of MCGO-functional guanidinium ionic liquid, the pH, the temperature and the extraction time were also presented. Moreover, the MCGO-functional guanidinium ionic liquid can be easily regenerated, and the extraction capacity was about 94% of the initial one after being used three times. Copyright © 2015 Elsevier B.V. All rights reserved.

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

PubMed

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

2016-12-01

Ionic liquids have great potential in biological applications and biocatalysis, as some ionic liquids can stabilize proteins and enhance enzyme activity, while others have the opposite effect. However, on the molecular level, probing ionic liquid interactions with proteins, especially in solutions containing high concentration of ionic liquids, has been challenging. In the present work the 13 C, 15 N-enriched GB1 model protein was used to demonstrate applicability of high-resolution magic-angle-spinning (HR-MAS) NMR spectroscopy to investigate ionic liquid - protein interactions. Effect of an ionic liquid (1-butyl-3-methylimidazolium bromide, [C 4 -mim]Br) on GB1was studied over a wide range of the ionic liquid concentrations (0.6 to 3.5 M, which corresponds to 10%-60% v/v). Interactions between GB1 and [C 4 -mim]Br were observed from changes in the chemical shifts of the protein backbone as well as the changes in 15 N ps-ns dynamics and rotational correlation times. Site-specific interactions between the protein and [C 4 -mim]Br were assigned using 3D methods under HR-MAS conditions. Thus, HR-MAS NMR is a viable tool that could aid in elucidation of the molecular mechanism of ionic liquid - protein interactions.

Toxicity of ionic liquids: eco(cyto)activity as complicated, but unavoidable parameter for task-specific optimization.

PubMed

Egorova, Ksenia S; Ananikov, Valentine P

2014-02-01

Rapid progress in the field of ionic liquids in recent decades led to the development of many outstanding energy-conversion processes, catalytic systems, synthetic procedures, and important practical applications. Task-specific optimization emerged as a sharpening stone for the fine-tuning of structure of ionic liquids, which resulted in unprecedented efficiency at the molecular level. Ionic-liquid systems showed promising opportunities in the development of green and sustainable technologies; however, the chemical nature of ionic liquids is not intrinsically green. Many ionic liquids were found to be toxic or even highly toxic towards cells and living organisms. In this Review, we show that biological activity and cytotoxicity of ionic liquids dramatically depend on the nature of a biological system. An ionic liquid may be not toxic for particular cells or organisms, but may demonstrate high toxicity towards another target present in the environment. Thus, a careful selection of biological activity data is a must for the correct assessment of chemical technologies involving ionic liquids. In addition to the direct biological activity (immediate response), several indirect effects and aftereffects are of primary importance. The following principal factors were revealed to modulate toxicity of ionic liquids: i) length of an alkyl chain in the cation; ii) degree of functionalization in the side chain of the cation; iii) anion nature; iv) cation nature; and v) mutual influence of anion and cation. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Use of ionic liquids as coordination ligands for organometallic catalysts

DOEpatents

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

2009-11-10

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

Predictive model for ionic liquid extraction solvents for rare earth elements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grabda, Mariusz; Oleszek, Sylwia; Institute of Environmental Engineering of the Polish Academy of Sciences, ul. M. Sklodowskiej-Curie 34, 41-819, Zabrze

2015-12-31

The purpose of our study was to select the most effective ionic liquid extraction solvents for dysprosium (III) fluoride using a theoretical approach. Conductor-like Screening Model for Real Solvents (COSMO-RS), based on quantum chemistry and the statistical thermodynamics of predefined DyF{sub 3}-ionic liquid systems, was applied to reach the target. Chemical potentials of the salt were predicted in 4,400 different ionic liquids. On the base of these predictions set of ionic liquids’ ions, manifesting significant decrease of the chemical potentials, were selected. Considering the calculated physicochemical properties (hydrophobicity, viscosity) of the ionic liquids containing these specific ions, the most effectivemore » extraction solvents for liquid-liquid extraction of DyF{sub 3} were proposed. The obtained results indicate that the COSMO-RS approach can be applied to quickly screen the affinity of any rare earth element for a large number of ionic liquid systems, before extensive experimental tests.« less

Hg⁰ removal from flue gas by ionic liquid/H₂O₂.

PubMed

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

2014-09-15

1-Alkyl-3-methylimidazolium chloride ionic liquids ([Cnmim] Cl, n=4, 6, 8) were prepared. The ionic liquid was then mixed with hydrogen peroxide (H2O2) to form an absorbent. The Hg(0) removal performance of the absorbent was investigated in a gas/liquid scrubber using simulated flue gas. It was found that the ionic liquid/H2O2 mixture was an excellent absorbent and could be used to remove Hg(0) from flue gas. When the mass ratio of H2O2 to ionic liquid was 0.5, the absorbent showed high Hg(0) removal efficiency (up to 98%). The Hg(0) removal efficiency usually increased with the absorption temperature, while decreased with the increase of alkyl chain length in ionic liquid molecule. The Hg(0) removal mechanism involved with Hg(0) oxidation by H2O2 and Hg(2+) transfer from aqueous phase to ionic liquid phase. Copyright © 2014 Elsevier B.V. All rights reserved.

Application of Ionic Liquids in Hydrometallurgy

PubMed Central

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

2014-01-01

Ionic liquids, low temperature molten salts, have various advantages manifesting themselves as durable and environmentally friendly solvents. Their application is expanding into various fields including hydrometallurgy due to their unique properties such as non-volatility, inflammability, low toxicity, good ionic conductivity, and wide electrochemical potential window. This paper reviews previous literatures and our recent results adopting ionic liquids in extraction, synthesis and processing of metals with an emphasis on the electrolysis of active/light, rare earth, and platinum group metals. Because the research and development of ionic liquids in this area are still emerging, various, more fundamental approaches are expected to popularize ionic liquids in the metal manufacturing industry. PMID:25177864

Design of Energetic Ionic Liquids (Preprint)

DTIC Science & Technology

2008-05-07

mesoscale-level simulations of bulk ionic liquids based upon multiscale coarse graining techniques. 15. SUBJECT TERMS 16. SECURITY...simulations utilizing polarizable force fields, and mesoscale-level simulations of bulk ionic liquids based upon multiscale coarse graining...Simulations of the Energetic Ionic Liquid 1-hydroxyethyl-4-amino-1, 2, 4- triazolium Nitrate (HEATN): Molecular dynamics (MD) simulations have been

Recent developments in biocatalysis in multiphasic ionic liquid reaction systems.

PubMed

Meyer, Lars-Erik; von Langermann, Jan; Kragl, Udo

2018-06-01

Ionic liquids are well known and frequently used 'designer solvents' for biocatalytic reactions. This review highlights recent achievements in the field of multiphasic ionic liquid-based reaction concepts. It covers classical biphasic systems including supported ionic liquid phases, thermo-regulated multi-component solvent systems (TMS) and polymerized ionic liquids. These powerful concepts combine unique reaction conditions with a high potential for future applications on a laboratory and industrial scale. The presence of a multiphasic system simplifies downstream processing due to the distribution of the catalyst and reactants in different phases.

Highly luminescent and color-tunable salicylate ionic liquids

DOE PAGES

Campbell, Paul S.; Yang, Mei; Pitz, Demian; ...

2014-03-11

High quantum yields of up to 40.5 % can be achieved in salicylate-bearing ionic liquids. A range of these ionic liquids have been synthesized and their photoluminescent properties studied in detail. The differences noted can be related back to the structure of the ionic liquid cation and possible interionic interactions. It is found that shifts of emission, particularly in the pyridinium-based ionic liquids, can be related to cation–anion pairing interactions. Furthermore, facile and controlled emission color mixing is demonstrated through combining different ILs, with emission colors ranging from blue to yellow.

Confused ionic liquid ions--a "liquification" and dosage strategy for pharmaceutically active salts.

PubMed

Bica, Katharina; Rogers, Robin D

2010-02-28

We present a strategy to expand the liquid and compositional ranges of ionic liquids, specifically pharmaceutically active ionic liquids, by simple mixing with a solid acid or base to form oligomeric ions.

Highly efficient conductivity modulation of cinnamate-based light-responsive ionic liquids in aqueous solutions.

PubMed

Yang, Jie; Wang, Huiyong; Wang, Jianji; Zhang, Yue; Guo, Zhongjia

2014-12-11

A new class of cinnamate-based light-responsive ionic liquids was synthesized and characterized, and these ionic liquids with longer alkyl chains showed a remarkable increase in ionic conductivity under UV light irradiation in aqueous solutions.

Thermotropic Ionic Liquid Crystals

PubMed Central

Axenov, Kirill V.; Laschat, Sabine

2011-01-01

The last five years’ achievements in the synthesis and investigation of thermotropic ionic liquid crystals are reviewed. The present review describes the mesomorphic properties displayed by organic, as well as metal-containing ionic mesogens. In addition, a short overview on the ionic polymer and self-assembled liquid crystals is given. Potential and actual applications of ionic mesogens are also discussed. PMID:28879986

Thermotropic Ionic Liquid Crystals.

PubMed

Axenov, Kirill V; Laschat, Sabine

2011-01-14

The last five years' achievements in the synthesis and investigation of thermotropic ionic liquid crystals are reviewed. The present review describes the mesomorphic properties displayed by organic, as well as metal-containing ionic mesogens. In addition, a short overview on the ionic polymer and self-assembled liquid crystals is given. Potential and actual applications of ionic mesogens are also discussed.

NafionxAE-based polymer actuators with ionic liquids as solvent incorporated at room temperature

NASA Astrophysics Data System (ADS)

Kikuchi, Kunitomo; Tsuchitani, Shigeki

2009-09-01

Nafion®-based ionic polymer-metal composites (IPMCs), with ionic liquids as solvent, were fabricated by exchanging counterions to ionic liquids at room temperature. Ion exchange is performed by only immersing IPMC in a mixture of de-ionized water and ionic liquids at room temperature for 48 h. The fabricated IPMCs exhibited a bending curvature the same as or larger than that of conventional IPMCs with ionic liquids, formed by ion exchange to ionic liquids at an elevated temperature up to about 100 °C, and also had long-term stability in operation in air, with a fluctuation smaller than 21% in bending curvature during a 180 min operation. The effective ion exchange to ionic liquids in the present method is probably due to an increase in diffusion speed of ionic liquids into IPMC by adsorption of water in a Nafion® membrane. It is a surprise that among IPMCs with ionic liquids 1-ethyl-3-methyl-imidazolium tetrafluoroborate, 1-buthyl-3-methyl-imidazolium tetrafluoroborate (BMIBF4), and 1-buthyl-3-methyl-imidazolium hexafluorophosphate (BMIPF6), IPMC with water-insoluble BMIPF6 exhibited a larger bending curvature than that IPMC with water-miscible BMIBF4. This might be due to effective incorporation of BMIPF6 into IPMC, since BMIPF6 has a higher affinity with IPMC than with water in the mixture of water and BMIPF6. From measurements of complex impedance and step voltage response of the driving current of IPMCs with ionic liquid, they are expressed by an equivalent circuit of a parallel combination of a serial circuit of membrane resistance of Nafion® and electric double layer capacitance at metal electrodes, with membrane capacitance of Nafion®, in a frequency range higher than about 0.1 Hz. The difference in magnitude of bending curvature in three kinds of IPMCs with ionic liquids is mainly due to the difference in bending response speed coming from the difference in the membrane resistance.

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

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

2014-11-01

An ionic liquid foam floatation coupled with ionic liquid dispersive liquid-liquid microextraction method was proposed for the extraction and concentration of 17-α-estradiol, 17-β-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. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ionic liquid compatibility in polyethylene oxide/siloxane ion gel membranes

DOE PAGES

Kusuma, Victor A.; Macala, Megan K.; Liu, Jian; ...

2018-10-02

Ion gel films were prepared by incorporating eight commercially available ionic liquids in two different cross-linked polymer matrices to evaluate their phase miscibility, gas permeability and ionic conductivity for potential applications as gas separation membranes and solid electrolyte materials. The ionic liquids cations were 1-ethyl-3-methylimidazolium, 1-ethyl-3-methylpyridinium, 1-butyl-1-methylpyrrolidinium, tributylmethylphosphonium, and butyltrimethylammonium with a common anion (bis(trifluoromethylsulfonyl)imide). In addition, ionic liquids with 1-ethyl-3-methylimidazolium cation with acetate, dicyanamide and tetrafluoroborate counterions were evaluated. The two polymers were cross-linked poly(ethylene oxide) and cross-linked poly(ethylene oxide)/siloxane copolymer. Differential scanning calorimetry, X-ray diffractometry and visual observations were performed to evaluate the ion gels’ miscibility, thermal stabilitymore » and homogeneity. Ionic liquids with the least basic anion (bis(trifluoromethylsulfonyl)imide) and aromatic cations containing acidic proton (e.g. imidazolium and pyridinium) gave the most stable and miscible ion gels. Phase stability was shown to be a function of both ionic liquid content and temperature, with phase separation observed at elevated temperatures. In conclusion, gas permeability testing with carbon dioxide and nitrogen and ionic conductivity measurements confirmed that these ionic liquids increased the gas permeability and ionic conductivity of the polymers.« less

Ionic liquid compatibility in polyethylene oxide/siloxane ion gel membranes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kusuma, Victor A.; Macala, Megan K.; Liu, Jian

Ion gel films were prepared by incorporating eight commercially available ionic liquids in two different cross-linked polymer matrices to evaluate their phase miscibility, gas permeability and ionic conductivity for potential applications as gas separation membranes and solid electrolyte materials. The ionic liquids cations were 1-ethyl-3-methylimidazolium, 1-ethyl-3-methylpyridinium, 1-butyl-1-methylpyrrolidinium, tributylmethylphosphonium, and butyltrimethylammonium with a common anion (bis(trifluoromethylsulfonyl)imide). In addition, ionic liquids with 1-ethyl-3-methylimidazolium cation with acetate, dicyanamide and tetrafluoroborate counterions were evaluated. The two polymers were cross-linked poly(ethylene oxide) and cross-linked poly(ethylene oxide)/siloxane copolymer. Differential scanning calorimetry, X-ray diffractometry and visual observations were performed to evaluate the ion gels’ miscibility, thermal stabilitymore » and homogeneity. Ionic liquids with the least basic anion (bis(trifluoromethylsulfonyl)imide) and aromatic cations containing acidic proton (e.g. imidazolium and pyridinium) gave the most stable and miscible ion gels. Phase stability was shown to be a function of both ionic liquid content and temperature, with phase separation observed at elevated temperatures. In conclusion, gas permeability testing with carbon dioxide and nitrogen and ionic conductivity measurements confirmed that these ionic liquids increased the gas permeability and ionic conductivity of the polymers.« less

Influence of the ionic liquid [C4mpy][Tf2N] on the structure of the miniprotein Trp-cage.

PubMed

Baker, Joseph L; Furbish, Jeffrey; Lindberg, Gerrick E

2015-11-01

We examine the effect of the ionic liquid [C4mpy][Tf2N] on the structure of the miniprotein Trp-cage and contrast these results with the behavior of Trp-cage in water. We find the ionic liquid has a dramatic effect on Trp-cage, though many similarities with aqueous Trp-cage are observed. We assess Trp-cage folding by monitoring root mean square deviation from the crystallographic structure, radius of gyration, proline cis/trans isomerization state, protein secondary structure, amino acid contact formation and distance, and native and non-native contact formation. Starting from an unfolded configuration, Trp-cage folds in water at 298 K in less than 500 ns of simulation, but has very little mobility in the ionic liquid at the same temperature, which can be ascribed to the higher ionic liquid viscosity. At 365 K, the mobility of the ionic liquid is increased and initial stages of Trp-cage folding are observed, however Trp-cage does not reach the native folded state in 2 μs of simulation in the ionic liquid. Therefore, in addition to conventional molecular dynamics, we also employ scaled molecular dynamics to expedite sampling, and we demonstrate that Trp-cage in the ionic liquid does closely approach the aqueous folded state. Interestingly, while the reduced mobility of the ionic liquid is found to restrict Trp-cage motion, the ionic liquid does facilitate proline cis/trans isomerization events that are not seen in our aqueous simulations. Copyright © 2015 Elsevier Inc. All rights reserved.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warner, Lisa; Gjersing, Erica; Follett, Shelby E.

Ionic liquids have great potential in biological applications and biocatalysis, as some ionic liquids can stabilize proteins and enhance enzyme activity, while others have the opposite effect. However, on the molecular level, probing ionic liquid interactions with proteins, especially in solutions containing high concentrations of ionic liquids, has been challenging. In the present work the 13C, 15N-enriched GB1 model protein was used to demonstrate applicability of high-resolution magic-angle-spinning (HR-MAS) NMR spectroscopy to investigate ionic liquid-protein interactions. Effect of an ionic liquid (1-butyl-3-methylimidazolium bromide, [C 4-mim]Br) on GB1was studied over a wide range of the ionic liquid concentrations (0.6-3.5 M, whichmore » corresponds to 10-60% v/v). Interactions between GB1 and [C 4-mim]Br were observed from changes in the chemical shifts of the protein backbone as well as the changes in 15N ps-ns dynamics and rotational correlation times. Site-specific interactions between the protein and [C 4-mim]Br were assigned using 3D methods under HR-MAS conditions. Furthermore, HR-MAS NMR is a viable tool that could aid in elucidation of molecular mechanisms of ionic liquid-protein interactions.« less

Comparison of Three Ionic Liquid-Tolerant Cellulases by Molecular Dynamics

PubMed Central

Jaeger, Vance; Burney, Patrick; Pfaendtner, Jim

2015-01-01

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

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

DOE PAGES

Warner, Lisa; Gjersing, Erica; Follett, Shelby E.; ...

2016-08-11

Ionic liquids have great potential in biological applications and biocatalysis, as some ionic liquids can stabilize proteins and enhance enzyme activity, while others have the opposite effect. However, on the molecular level, probing ionic liquid interactions with proteins, especially in solutions containing high concentrations of ionic liquids, has been challenging. In the present work the 13C, 15N-enriched GB1 model protein was used to demonstrate applicability of high-resolution magic-angle-spinning (HR-MAS) NMR spectroscopy to investigate ionic liquid-protein interactions. Effect of an ionic liquid (1-butyl-3-methylimidazolium bromide, [C 4-mim]Br) on GB1was studied over a wide range of the ionic liquid concentrations (0.6-3.5 M, whichmore » corresponds to 10-60% v/v). Interactions between GB1 and [C 4-mim]Br were observed from changes in the chemical shifts of the protein backbone as well as the changes in 15N ps-ns dynamics and rotational correlation times. Site-specific interactions between the protein and [C 4-mim]Br were assigned using 3D methods under HR-MAS conditions. Furthermore, HR-MAS NMR is a viable tool that could aid in elucidation of molecular mechanisms of ionic liquid-protein interactions.« less

Graphene-ionic liquid composites

DOEpatents

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

2016-11-01

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

Ionic Liquids for Advanced Materials

DTIC Science & Technology

2008-12-01

optical clarity to completely opacity with increased amounts of ionic liquid . This transition was not previously observed in Nafion ® membranes swollen...1 IONIC LIQUIDS FOR ADVANCED MATERIALS Timothy E. Long, Sean M. Ramirez, Randy Heflin, Harry W. Gibson, Louis A. Madsen, Donald J. Leo, Nakhiah...is to develop a micromechanical model for the electrochemomechanical transduction mechanisms in newly synthesized ionic liquid polymers in order to

WtF‐Nano: One‐Pot Dewatering and Water‐Free Topochemical Modification of Nanocellulose in Ionic Liquids or γ‐Valerolactone

PubMed Central

Laaksonen, Tiina; Helminen, Jussi K. J.; Lemetti, Laura; Långbacka, Jesper; Rico del Cerro, Daniel; Hummel, Michael; Rantamäki, Antti H.; Kakko, Tia; Kemell, Marianna L.; Wiedmer, Susanne K.; Heikkinen, Sami; Kilpeläinen, Ilkka

2017-01-01

Abstract Ionic liquids are used to dewater a suspension of birch Kraft pulp cellulose nanofibrils (CNF) and as a medium for water‐free topochemical modification of the nanocellulose (a process denoted as “WtF‐Nano”). Acetylation was applied as a model reaction to investigate the degree of modification and scope of effective ionic liquid structures. Little difference in reactivity was observed when water was removed, after introduction of an ionic liquid or molecular co‐solvent. However, the viscoelastic properties of the CNF suspended in two ionic liquids show that the more basic, but non‐dissolving ionic liquid, allows for better solvation of the CNF. Vibrio fischeri bacterial tests show that all ionic liquids in this study were harmless. Scanning electron microscopy and wide‐angle X‐ray scattering on regenerated samples show that the acetylated CNF is still in a fibrillar form. 1 D and 2 D NMR analyses, after direct dissolution in a novel ionic liquid electrolyte solution, indicate that both cellulose and residual xylan on the surface of the nanofibrils reacts to give acetate esters. PMID:29112334

Evaluation of Vapor Pressure and Ultra-High Vacuum Tribological Properties of Ionic Liquids (2) Mixtures and Additives

NASA Technical Reports Server (NTRS)

Morales, Wilfredo; Koch, Victor R.; Street, Kenneth W., Jr.; Richard, Ryan M.

2008-01-01

Ionic liquids are salts, many of which are typically viscous fluids at room temperature. The fluids are characterized by negligible vapor pressures under ambient conditions. These properties have led us to study the effectiveness of ionic liquids containing both organic cations and anions for use as space lubricants. In the previous paper we have measured the vapor pressure and some tribological properties of two distinct ionic liquids under simulated space conditions. In this paper we will present vapor pressure measurements for two new ionic liquids and friction coefficient data for boundary lubrication conditions in a spiral orbit tribometer using stainless steel tribocouples. In addition we present the first tribological data on mixed ionic liquids and an ionic liquid additive. Post mortem infrared and Raman analysis of the balls and races indicates the major degradation pathway for these two organic ionic liquids is similar to those of other carbon based lubricants, i.e. deterioration of the organic structure into amorphous graphitic carbon. The coefficients of friction and lifetimes of these lubricants are comparable to or exceed these properties for several commonly used space oils.

Electropolymerized polyazulene as active material in flexible supercapacitors

NASA Astrophysics Data System (ADS)

Suominen, Milla; Lehtimäki, Suvi; Yewale, Rahul; Damlin, Pia; Tuukkanen, Sampo; Kvarnström, Carita

2017-07-01

We report the capacitive behavior of electrochemically polymerized polyazulene films in different ionic liquids. The ionic liquids in this study represent conventional imidazolium based ionic liquids with tetrafluoroborate and bis(trifluoromethylsulfonyl)imide anions as well as an unconventional choline based ionic liquid. The effect of different ionic liquids on the polymerization and capacitive performance of polyazulene films is demonstrated by cyclic voltammetry and electrochemical impedance spectroscopy in a 3-electrode cell configuration. The films exhibit the highest capacitances in the lowest viscosity ionic liquid (92 mF cm-2), while synthesis in high viscosity ionic liquid shortens the conjugation length and results in lower electroactivity (25 mF cm-2). The obtained films also show good cycling stabilities retaining over 90% of their initial capacitance over 1200 p-doping cycles. We also demonstrate, for the first time, flexible polyazulene supercapacitors of symmetric and asymmetric configurations using the choline based ionic liquid as electrolyte. In asymmetric configuration, capacitance of 55 mF (27 mF cm-2) with an equivalent series resistance of 19 Ω is obtained at operating voltage of 1.5 V. Upon increasing the operating voltage up to 2.4 V, the capacitance increases to 72 mF (36 mF cm-2).

X-ray Photoelectron Spectroscopy of Pyridinium-Based Ionic Liquids: Comparison to Imidazolium- and Pyrrolidinium-Based Analogues.

PubMed

Men, Shuang; Mitchell, Daniel S; Lovelock, Kevin R J; Licence, Peter

2015-07-20

We investigate eight 1-alkylpyridinium-based ionic liquids of the form [Cn Py][A] by using X-ray photoelectron spectroscopy (XPS). The electronic environment of each element of the ionic liquids is analyzed. In particular, a reliable fitting model is developed for the C 1s region that applies to each of the ionic liquids. This model allows the accurate charge correction of binding energies and the determination of reliable and reproducible binding energies for each ionic liquid. Shake-up/off phenomena are determinedfor both C 1s and N 1s spectra. The electronic interaction between cations and anions is investigated for both simple ionic liquids and an example of an ionic-liquid mixture; the effect of the anion on the electronic environment of the cation is also explored. Throughout the study, a detailed comparison is made between [C8 Py][A] and analogues including 1-octyl-1-methylpyrrolidinium- ([C8 C1 Pyrr][A]), and 1-octyl-3-methylimidazolium- ([C8 C1 Im][A]) based samples, where X is common to all ionic liquids. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ionic Liquids as Quasihydrostatic Pressure Media for Diamond Anvil Cell Experiments

NASA Astrophysics Data System (ADS)

Mayorga, Sierra; Moldowan, Kaela; Dan, Ioana; Forster, Paul; Iota, Valentin

2012-02-01

Ionic liquids (ILs) are salts in which the ions are poorly coordinated to the point where the eutectic mixture remains liquid at room temperature. In general, ILs exhibit high chemical and thermal stability, have extended liquid regions in the pressure-temperature domain, and can be easily obtained. Commercial ionic liquids are relatively inexpensive and custom ionic solutions can be easily synthesized by mixing common reactants. These properties make ionic liquids attractive candidates for high-pressure media in Diamond Anvil Cell (DAC) experiments. In this presentation we explore the use of ionic liquids as DAS quasihydrostatic pressure media for pressures up to 50 GPa. As a measure of hydrostaticity we monitor the splitting and peak-widths of the R1 andR 2 fluorescence lines from small ruby chips (Al2O3 :Cr^3+) imbedded in the pressure medium. We present results on a series of commercially available ionic fluids against standard pressure media: methanol-ethanol mixtures, silicone oil, sodium chloride (NaCl) and noble gases (Ar, Ne, He).

Exploiting 1,2,3-Triazolium Ionic Liquids for Synthesis of Tryptanthrin and Chemoselective Extraction of Copper(II) Ions and Histidine-Containing Peptides.

PubMed

Li, Hsin-Yi; Chen, Chien-Yuan; Cheng, Hui-Ting; Chu, Yen-Ho

2016-10-13

Based on a common structural core of 4,5,6,7-tetrahydro[1,2,3]triazolo[1,5- a ]pyridine, a number of bicyclic triazolium ionic liquids 1 - 3 were designed and successfully prepared. In our hands, this optimized synthesis of ionic liquids 1 and 2 requires no chromatographic separation. Also in this work, ionic liquids 1 , 2 were shown to be efficient ionic solvents for fast synthesis of tryptanthrin natural product. Furthermore, a new affinity ionic liquid 3 was tailor-synthesized and displayed its effectiveness in chemoselective extraction of both Cu(II) ions and, for the first time, histidine-containing peptides.

Ion Transport in Nanostructured Block Copolymer/Ionic Liquid Membranes

NASA Astrophysics Data System (ADS)

Hoarfrost, Megan Lane

Incorporating an ionic liquid into one block copolymer microphase provides a platform for combining the outstanding electrochemical properties of ionic liquids with a number of favorable attributes provided by block copolymers. In particular, block copolymers thermodynamically self-assemble into well-ordered nanostructures, which can be engineered to provide a durable mechanical scaffold and template the ionic liquid into continuous ion-conducting nanochannels. Understanding how the addition of an ionic liquid affects the thermodynamic self-assembly of block copolymers, and how the confinement of ionic liquids to block copolymer nanodomains affects their ion-conducting properties is essential for predictable structure-property control. The lyotropic phase behavior of block copolymer/ionic liquid mixtures is shown to be reminiscent of mixtures of block copolymers with selective molecular solvents. A variety of ordered microstructures corresponding to lamellae, hexagonally close-packed cylinders, body-centered cubic, and face-centered cubic oriented micelles are observed in a model system composed of mixtures of imidazolium bis(trifluoromethylsulfonyl)imide ([Im][TFSI]) and poly(styrene- b-2-vinyl pyridine) (PS-b-P2VP). In contrast to block copolymer/molecular solvent mixtures, the interfacial area occupied by each PS-b-P2VP chain decreases upon the addition of [Im][TFSI], indicating a considerable increase in the effective segregation strength of the PS-b-P2VP copolymer with ionic liquid addition. The relationship between membrane structure and ionic conductivity is illuminated through the development of scaling relationships that describe the ionic conductivity of block copolymer/ionic liquid mixtures as a function of membrane composition and temperature. It is shown that the dominant variable influencing conductivity is the overall volume fraction of ionic liquid in the mixture, which means there is incredible freedom in designing the block copolymer architecture in order to optimize the mechanical and other properties of the membrane without sacrificing conductivity. The derived scaling relationships are shown to be general for many block copolymer and ionic liquid chemistries. In certain cases, the mechanism of ion conduction in the ionic liquid is affected by block copolymer nanoconfinement. The introduction of excess neutral imidazole to [Im][TFSI] leads to enhanced proton conductivity as well as a high H+ transference number due to facilitated proton hopping between imidazole molecules. We show that there is increased proton hopping when the nonstoichiometric ionic liquid is confined to lamellar block copolymer nanodomains, which we hypothesize is due to changes in the hydrogen bond structure of the ionic liquid under confinement. This, in combination with unique ion aggregation behavior, leads to a lower activation energy for macroscopic ion transport compared to that in a corresponding homopolymer/ionic liquid mixture. Through this work, we further the understanding of the relationship between membrane composition, structure, and ion transport. The findings presented herein portend the rational design of nanostructured membranes having improved mechanical properties and conductivity.

Ionic liquid-tolerant cellulase enzymes

DOEpatents

Gladden, John; Park, Joshua; Singer, Steven; Simmons, Blake; Sale, Ken

2017-10-31

The present invention provides ionic liquid-tolerant cellulases and method of producing and using such cellulases. The cellulases of the invention are useful in saccharification reactions using ionic liquid treated biomass.

The molecular assembly of the ionic liquid/aliphatic carboxylic acid/aliphatic amine as effective and safety transdermal permeation enhancers.

PubMed

Kubota, Koji; Shibata, Akira; Yamaguchi, Toshikazu

2016-04-30

In spite of numerous advantages, transdermal drug delivery systems are unfeasible for most drugs because of the barrier effect of the stratum corneum. Ionic liquids were recently used to enhance transdermal drug delivery by improving drug solubility. In the present study, safe and effective ionic liquids for transdermal absorption were obtained as salts generated by a neutralization reaction between highly biocompatible aliphatic carboxylic acids (octanoic acid or isostearic acid) and aliphatic amines (diisopropanolamine or triisopropanolamine) (Medrx Co., Ltd., 2009). The mechanism of skin permeability enhancement by ionic liquids was investigated by hydrophilic phenol red and hydrophobic tulobuterol. Further, the skin permeation enhancing effect was remarkably superior in the acid excess state rather than the neutralization state. Infrared absorption spectrum analysis confirmed that ionic liquids/aliphatic carboxylic acid/aliphatic amine are coexisting at all mixing states. In the acid excess state, ionic liquids interact with aliphatic carboxylic acids via hydrogen bonds. Thus, the skin permeation enhancing effect is not caused by the ionic liquid alone. The "liquid salt mixture," referred to as a complex of ingredients coexisting with ionic liquids, forms a molecular assembly incorporating hydrophilic drug. This molecular assembly was considered an effective and safety enhancer of transdermal drug permeation. Copyright © 2016. Published by Elsevier B.V.

New ionic liquids based on complexation of dipropylsulfide and AlCl3 for electrochodeposition of aluminum

DOE PAGES

Fang, Youxing; Jiang, Xueguang; Dai, Sheng; ...

2015-07-14

A new kind of ionic liquid based on complexation of dipropyl sulfide (DPS) and AlCl 3 has been prepared. The equivalent concentration of AlCl3 in the ionic liquid is as high as 2.3 M. More importantly, it is highly fluidic and exhibits an ambient ionic conductivity of 1.25 x 10 -4 S cm -1. This new ionic liquid can be successfully used as an electrolyte for electrodeposition of aluminum.

New ionic liquids based on complexation of dipropylsulfide and AlCl3 for electrochodeposition of aluminum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fang, Youxing; Jiang, Xueguang; Dai, Sheng

A new kind of ionic liquid based on complexation of dipropyl sulfide (DPS) and AlCl 3 has been prepared. The equivalent concentration of AlCl3 in the ionic liquid is as high as 2.3 M. More importantly, it is highly fluidic and exhibits an ambient ionic conductivity of 1.25 x 10 -4 S cm -1. This new ionic liquid can be successfully used as an electrolyte for electrodeposition of aluminum.

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

PubMed

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

2017-07-01

A novel microextraction method, termed microwave-assisted ionic liquid/ionic liquid dispersive liquid-liquid microextraction, has been developed for the rapid enrichment and analysis of triazine herbicides in fruit juice samples by high-performance liquid chromatography. Instead of using hazardous organic solvents, two kinds of ionic liquids, a hydrophobic ionic liquid (1-hexyl-3-methylimidazolium hexafluorophosphate) and a hydrophilic ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate), were used as the extraction solvent and dispersion agent, respectively, in this method. The extraction procedure was induced by the formation of cloudy solution, which was composed of fine drops of 1-hexyl-3-methylimidazolium hexafluorophosphate dispersed entirely into sample solution with the help of 1-butyl-3-methylimidazolium tetrafluoroborate. In addition, an ion-pairing agent (NH 4 PF 6 ) was introduced to improve recoveries of the ionic liquid phase. Several experimental parameters that might affect the extraction efficiency were investigated. Under the optimum experimental conditions, the linearity for determining the analytes was in the range of 5.00-250.00 μg/L, with the correlation coefficients of 0.9982-0.9997. The practical application of this effective and green method is demonstrated by the successful analysis of triazine herbicides in four juice samples, with satisfactory recoveries (76.7-105.7%) and relative standard deviations (lower than 6.6%). In general, this method is fast, effective, and robust to determine triazine herbicides in juice samples. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Acoustic cavitation in 1-butyl-3-methylimidazolium bis(triflluoromethyl-sulfonyl)imide based ionic liquid.

PubMed

Merouani, Slimane; Hamdaoui, Oualid; Haddad, Boumediene

2018-03-01

In this work, a comparison between the temperatures/pressures within acoustic cavitation bubble in an imidazolium-based room-temperature ionic liquid (RTIL), 1-butyl-3-methylimidazolium bis(triflluoromethyl-sulfonyl)imide ([BMIM][NTf 2 ]), and in water has been made for a wide range of cavitation parameters including frequency (140-1000kHz), acoustic intensity (0.5-1Wcm -2 ), liquid temperature (20-50°C) and external static pressure (0.7-1.5atm). The used cavitation model takes into account the liquid compressibility as well as the surface tension and the viscosity of the medium. It was found that the bubble temperatures and pressures were always much higher in the ionic liquid compared to those predicted in water. The valuable effect of [BMIM][NTf 2 ] on the bubble temperature was more pronounced at higher acoustic intensity and liquid temperature and lower frequency and external static pressure. However, confrontation between the predicted and the experimental estimated temperatures in ionic liquids showed an opposite trend as the temperatures measured in some pure ionic liquids are of the same order as those observed in water. The injection of liquid droplets into cavitation bubbles, the pyrolysis of ionic liquids at the bubble-solution interface as well as the lower number of collapsing bubbles in the ionic liquid may be the responsible for the lower measured bubble temperatures in ionic liquids, as compared with water. Copyright © 2017 Elsevier B.V. All rights reserved.

Methods of using ionic liquids having a fluoride anion as solvents

DOEpatents

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

2011-12-06

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

Ionic Liquids in HPLC and CE: A Hope for Future.

PubMed

Ali, Imran; Suhail, Mohd; Sanagi, Mohd Marsin; Aboul-Enein, Hassan Y

2017-07-04

The ionic liquids (ILs) are salts with melting points below 100°C. These are called as ionic fluids, ionic melts, liquid electrolytes, fused salts, liquid salts, ionic glasses, designer solvents, green solvents and solvents of the future. These have a wide range of applications, including medical, pharmaceutical and chemical sciences. Nowadays, their use is increasing greatly in separation science, especially in chromatography and capillary electrophoresis due to their remarkable properties. The present article describes the importance of ILs in high-performance liquid chromatography and capillary electrophoresis. Efforts were also made to highlight the future expectations of ILs.

Prominent roles of impurities in ionic liquid for catalytic conversion of carbohydrates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, Haibo; Brown, Heather M.; Holladay, Johnathan E.

2012-02-07

In the last two decades, ionic liquids have emerged as new and versatile solvents, and many of them are also catalysts for a broad range of catalytic reactions. Certain ionic liquids have been found to possess the unique capability of dissolving cellulosic biomass. The potential of such ionic liquids as solvent to enable catalytic conversion of cellulosic polymers was first explored and demonstrated by Zhao et al. This field of research has since experienced a rapid growth. Most ionic liquids have negligible vapor pressure and excellent thermal stability over a wide temperature range. For example, ionic liquids composed of 1-ethyl-3-methylimidazoliummore » (EMIM+) cation and Cl- anion was reported to be stable up to 285 C, while salts of the same cation with other anions such as BF4- and PF6- are thermally stable above 380 C under inert atmosphere. It is well known that presence of impurities in ionic liquids typically causes changes in physical properties, e.g. decreasing in melting point and viscosity. Addition of Lewis acidic metal chlorides, e.g. AlCl3 to 1-alkyl-3-methylimidazolium chloride, [AMIM]Cl, is an exothermic reaction and considerably reduces the melting point by forming [AMIM]AlCl4 or [AMIM]Al2Cl7 that are also ionic liquids but have much lower melting point than the parent [AMIM]Cl. While most early research on catalysis of ionic liquids involving metallohalide anions were typically conducted from stoichiometric ratio of such anions to organic cations, e.g. [AMIM]+, the use of pure ionic liquids only as a solvent to carry out catalysis by a catalytic amount of a metal halide as catalyst truly displayed the solvent property of such ionic liquids.4 In such reaction systems, catalytic amounts of metal halides were used to catalyze the conversion of glucose and cellulose.4,11,12 The metal chloride catalyst concentration was in the order of 10-3 M. The presence of another metal chloride in the ionic liquids, even in the order of 10-5 M concentration was found to bring a dramatic synergistic effect. Therefore, the catalytic performance of the metal halide catalyst for the conversion of carbohydrates in the ionic liquid systems is highly sensitive to the presence of impurities. This work presents findings on the role of impurities that were present in some commercially available ionic liquids used for the conversion of the cellulose.« less

Ionic liquid-modified materials for solid-phase extraction and separation: a review.

PubMed

Vidal, Lorena; Riekkola, Marja-Liisa; Canals, Antonio

2012-02-17

In recent years, materials science has propelled to the research forefront. Ionic liquids with unique and fascinating properties have also left their footprints to the developments of materials science during the last years. In this review we highlight some of their recent advances and provide an overview at the current status of ionic liquid-modified materials applied in solid-phase extraction, liquid and gas chromatography and capillary electrochromatography with reference to recent applications. In addition, the potential of ionic liquids in the modification of capillary inner wall in capillary electrophoresis is demonstrated. The main target material modified with ionic liquids is silica, but polymers and monoliths have recently joined the studies. Although imidazolium is still clearly the most commonly used ionic liquid for the covalently modification of materials, the exploitation of pyridinium and phosphonium will most probably increase in the future. Copyright © 2011 Elsevier B.V. All rights reserved.

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

PubMed

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

2016-12-01

Salting-out homogenous extraction followed by ionic liquid/ionic liquid dispersive liquid-liquid micro-extraction system was developed and applied to the extraction of sulfonamides in blood. High-performance liquid chromatography was applied to the determination of the analytes. The blood sample was centrifuged to obtain the serum. After the proteins in the serum were removed in the presence of acetonitrile, ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate, dipotassium hydrogen phosphate, ionic liquid 1-Hexyl-3-methylimidazolium hexafluorophosphate were added into the resulting solution. After the resulting mixture was ultrasonically shaken and centrifuged, the precipitate was separated. The acetonitrile was added in the precipitate and the analytes were extracted into the acetonitrile phase. The parameters affecting the extraction efficiency, such as volume of ionic liquid, amount of dipotassium hydrogen phosphate, volume of dispersant, extraction time and temperature were investigated. The limits of detection of sulfamethizole (STZ), sulfachlorpyridazine (SCP), sulfamethoxazole (SMX) and Sulfisoxazole (SSZ) were 4.78, 3.99, 5.21 and 3.77μgL -1 , respectively. When the present method was applied to the analysis of real blood samples, the recoveries of analytes ranged from 90.0% to 113.0% and relative standard deviations were lower than 7.2%. Copyright © 2016 Elsevier B.V. All rights reserved.

Enzyme catalysis with small ionic liquid quantities.

PubMed

Fischer, Fabian; Mutschler, Julien; Zufferey, Daniel

2011-04-01

Enzyme catalysis with minimal ionic liquid quantities improves reaction rates, stereoselectivity and enables solvent-free processing. In particular the widely used lipases combine well with many ionic liquids. Demonstrated applications are racemate separation, esterification and glycerolysis. Minimal solvent processing is also an alternative to sluggish solvent-free catalysis. The method allows simplified down-stream processing, as only traces of ionic liquids have to be removed.

Ionic Liquid Fuels for Chemical Propulsion

DTIC Science & Technology

2016-10-31

nucleophilicity in the ionic liquid is critical. Both gas -phase and condensed-phase (CPCM-GIL) density functional theory calculations support the...stability trends in dialkylimidazolium ionic liquids and could be used as a higher accuracy method than the gas -phase DFT approach for predicting thermal...stabilities of ionic liquids in general. One important finding from the comparison of the gas -phase basicities relative to the GIL condensed- phase

Kamlet-Taft solvent parameters, NMR spectroscopic analysis and thermoelectrochemistry of lithium-glyme solvate ionic liquids and their dilute solutions.

PubMed

Black, Jeffrey J; Dolan, Andrew; Harper, Jason B; Aldous, Leigh

2018-06-06

Solvate ionic liquids are a relatively new class of liquids produced by combining a coordinating solvent with a salt. They have a variety of uses and their suitability for such depends upon the ratio of salt to coordinating solvent. This work investigates the Kamlet-Taft solvent parameters of, NMR chemical shifts of nuclei in, and thermoelectrochemistry of a selected set of solvate ionic liquids produced from glymes (methyl terminated oligomers of ethylene glycol) and lithium bis(trifluoromethylsulfonyl)imide at two different compositions. The aim is to improve the understanding of the interactions occurring in these ionic liquids to help select suitable solvate ionic liquids for future applications.

Ionic Liquid-Liquid Chromatography: A New General Purpose Separation Methodology.

PubMed

Brown, Leslie; Earle, Martyn J; Gîlea, Manuela A; Plechkova, Natalia V; Seddon, Kenneth R

2017-08-10

Ionic liquids can form biphasic solvent systems with many organic solvents and water, and these solvent systems can be used in liquid-liquid separations and countercurrent chromatography. The wide range of ionic liquids that can by synthesised, with specifically tailored properties, represents a new philosophy for the separation of organic, inorganic and bio-based materials. A customised countercurrent chromatograph has been designed and constructed specifically to allow the more viscous character of ionic liquid-based solvent systems to be used in a wide variety of separations (including transition metal salts, arenes, alkenes, alkanes, bio-oils and sugars).

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

PubMed

Shojaatalhosseini, Mansoureh; Elamin, Khalid; Swenson, Jan

2017-10-19

In this study, we have used nanocomposite polymer electrolytes, consisting of poly(ethylene oxide) (PEO), δ-Al 2 O 3 nanoparticles, and lithium bis(trifluoromethanesolfonyl)imide (LiTFSI) salt (with 4 wt % δ-Al 2 O 3 and PEO:Li ratios of 16:1 and 8:1), and added different amounts of the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesolfonyl)imide (BMITFSI). The aim was to elucidate whether the ionic liquid is able to dissociate the Li-ions from the ether oxygens and thereby decouple the ionic conductivity from the segmental polymer dynamics. The results from DSC and dielectric spectroscopy show that the ionic liquid speeds up both the segmental polymer dynamics and the motion of the Li + ions. However, a close comparison between the structural (α) relaxation process, given by the segmental polymer dynamics, and the ionic conductivity shows that the motion of the Li + ions decouples from the segmental polymer dynamics at higher concentrations of the ionic liquid (≥20 wt %) and instead becomes more related to the viscosity of the ionic liquid. This decoupling increases with decreasing temperature. In addition to the structural α-relaxation, two more local relaxation processes, denoted β and γ, are observed. The β-relaxation becomes slightly faster at the highest concentration of the ionic liquid (at least for the lower salt concentration), whereas the γ-relaxation is unaffected by the ionic liquid, over the whole concentration range 0-40 wt %.

Effects of phosphonium-based ionic liquids on phospholipid membranes studied by small-angle X-ray scattering.

PubMed

Kontro, Inkeri; Svedström, Kirsi; Duša, Filip; Ahvenainen, Patrik; Ruokonen, Suvi-Katriina; Witos, Joanna; Wiedmer, Susanne K

2016-12-01

The effects of ionic liquids on model phospholipid membranes were studied by small-angle X-ray scattering, dynamic light scattering (DLS) and zeta potential measurements. Multilamellar 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine liposomes and large unilamellar vesicles composed of l-α-phosphatidylcholine (eggPC) and l-α-phosphatidylglycerol (eggPG) (80:20mol%) or eggPC, eggPG, and cholesterol (60:20:20mol%) were used as biomimicking membrane models. The effects of the phosphonium-based ionic liquids: tributylmethylphosphonium acetate, trioctylmethylphosphonium acetate, tributyl(tetradecyl)-phosphonium acetate, and tributyl(tetradecyl)-phosphonium chloride, were compared to those of 1-ethyl-3-methyl-imidazolium acetate. With multilamellar vesicles, the ionic liquids that did not disrupt liposomes decreased the lamellar spacing as a function of concentration. The magnitude of the effect depended on concentration for all studied ionic liquids. Using large unilamellar vesicles, first a slight decrease in the vesicle size, then aggregation of vesicles was observed by DLS for increasing ionic liquid concentrations. At concentrations just below those that caused aggregation of liposomes, large unilamellar vesicles were coated by ionic liquid cations, evidenced by a change in their zeta potential. The ability of phosphonium-based ionic liquids to affect liposomes is related to the length of the hydrocarbon chains in the cation. Generally, the ability of ionic liquids to disrupt liposomes goes hand in hand with inducing disorder in the phospholipid membrane. However, trioctylmethylphosphonium acetate selectively extracted and induced a well-ordered lamellar structure in phospholipids from disrupted cholesterol-containing large unilamellar vesicles. This kind of effect was not seen with any other combination of ionic liquids and liposomes. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

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

PubMed

Zhao, Dishun; Wang, Yanan; Duan, Erhong

2009-10-28

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

Surface-active ionic liquids for palladium-catalysed cross coupling in water: effect of ionic liquid concentration on the catalytically active species† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c7ra07757b

PubMed Central

Taskin, Meltem; Cognigni, Alice; Zirbs, Ronald; Reimhult, Erik

2017-01-01

We report the design and synthesis of surface-active ionic liquids for application in palladium-catalyzed cross coupling reactions. A series of dodecylimidazolium-based ionic liquids were applied as additives in the Heck reaction of ethyl acrylate and iodobenzene, and high yields of >90% could be obtained in water without the addition of further ligands. Our results indicate that the ionic liquid concentration in water is the key factor affecting the formation of the catalytically active species and hence the yield. Moreover, imidazolium-based ionic liquids that are able to form a carbene species differ significantly from conventional cationic surfactants, as a concentration dependent formation of the N-heterocyclic carbene complex was observed. PMID:29308189

Computational solvation analysis of biomolecules in aqueous ionic liquid mixtures : From large flexible proteins to small rigid drugs.

PubMed

Zeindlhofer, Veronika; Schröder, Christian

2018-06-01

Based on their tunable properties, ionic liquids attracted significant interest to replace conventional, organic solvents in biomolecular applications. Following a Gartner cycle, the expectations on this new class of solvents dropped after the initial hype due to the high viscosity, hydrolysis, and toxicity problems as well as their high cost. Since not all possible combinations of cations and anions can be tested experimentally, fundamental knowledge on the interaction of the ionic liquid ions with water and with biomolecules is mandatory to optimize the solvation behavior, the biodegradability, and the costs of the ionic liquid. Here, we report on current computational approaches to characterize the impact of the ionic liquid ions on the structure and dynamics of the biomolecule and its solvation layer to explore the full potential of ionic liquids.

Novel ascorbic acid based ionic liquids for the in situ synthesis of quasi-spherical and anisotropic gold nanostructures in aqueous medium.

PubMed

Dinda, Enakshi; Si, Satyabrata; Kotal, Atanu; Mandal, Tarun K

2008-01-01

A series of newly designed ascorbic acid based room temperature ionic liquids were successfully used to prepare quasi-spherical and anisotropic gold nanostructures in an aqueous medium at ambient temperature. The synthesis of these room temperature ionic liquids involves, first, the preparation of a 1-alkyl (such as methyl, ethyl, butyl, hexyl, octyl, and decyl) derivative of 3-methylimidazolium hydroxide followed by the neutralization of the derivatised product with ascorbic acid. These ionic liquids show significantly better thermal stability and their glass transition temperature (Tg) decreases with increasing alkyl chain length. The ascorbate counter anion of these ionic liquids acts as a reducing agent for HAuCl4 to produce metallic gold and the alkylated imidazolium counter cation acts as a capping/shape-directing agent. It has been found that the nature of the ionic liquids and the mole ratio of ionic liquid to HAuCl4 has a significant effect on the morphology of the formed gold nanostructures. If an equimolar mixture of ionic liquid and HAuCl4 is used, predominantly anisotropic gold nanostructures are formed and by varying the alkyl chain length attached to imidazolium cation of the ionic liquids, various particle morphologies can formed, such as quasispherical, raspberry-like, flakes or dendritic. A probable formation mechanism for such anisotropic gold nanostructures has been proposed, which is based on the results of some control experiments.

Charge Transport and Phase Behavior of Imidazolium-Based Ionic Liquid Crystals from Fully Atomistic Simulations.

PubMed

Quevillon, Michael J; Whitmer, Jonathan K

2018-01-02

Ionic liquid crystals occupy an intriguing middle ground between room-temperature ionic liquids and mesostructured liquid crystals. Here, we examine a non-polarizable, fully atomistic model of the 1-alkyl-3-methylimidazolium nitrate family using molecular dynamics in the constant pressure-constant temperature ensemble. These materials exhibit a distinct "smectic" liquid phase, characterized by layers formed by the molecules, which separate the ionic and aliphatic moieties. In particular, we discuss the implications this layering may have for electrolyte applications.

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

PubMed

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

2015-08-04

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

The Colloidal Stability of Magnetic Nanoparticles in Ionic Liquids

DTIC Science & Technology

2015-08-03

Ionic Liquids 5a. CONTRACT NUMBER FA2386-14-1-4062 5b. GRANT NUMBER Grant 14IOA088 AOARD-144062 5c. PROGRAM ELEMENT NUMBER 61102F 6...NOTES 14. ABSTRACT During the reporting period the development of the ionic liquid ferrofluid (ILFF) based on EMIM-NTf2 was continued. The...ferrofluids based on other high-boiling solvents. 15. SUBJECT TERMS Electric Propulsion, Ionic liquids 16. SECURITY CLASSIFICATION

Basicity of pyridine and some substituted pyridines in ionic liquids.

PubMed

Angelini, Guido; De Maria, Paolo; Chiappe, Cinzia; Fontana, Antonella; Pierini, Marco; Siani, Gabriella

2010-06-04

The equilibrium constants for ion pair formation of some pyridines have been evaluated by spectrophotometric titration with trifluoroacetic acid in different ionic liquids. The basicity order is the same in ionic liquids and in water. The substituent effect on the equilibrium constant has been discussed in terms of the Hammett equation. Pyridine basicity appears to be less sensitive to the substituent effect in ionic liquids than in water.

Computational prediction of ionic liquid 1-octanol/water partition coefficients.

PubMed

Kamath, Ganesh; Bhatnagar, Navendu; Baker, Gary A; Baker, Sheila N; Potoff, Jeffrey J

2012-04-07

Wet 1-octanol/water partition coefficients (log K(ow)) predicted for imidazolium-based ionic liquids using adaptive bias force-molecular dynamics (ABF-MD) simulations lie in excellent agreement with experimental values. These encouraging results suggest prospects for this computational tool in the a priori prediction of log K(ow) values of ionic liquids broadly with possible screening implications as well (e.g., prediction of CO(2)-philic ionic liquids).

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

PubMed

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

2016-09-01

With the advent of ionic liquids, much was expected concerning their applicability as an alternative to organic solvents in the chemical technology and biotechnology fields. However, the most studied and commonly used ionic liquids based on imidazolium and pyridinium were found not to be as environmentally friendly as it was first expected. Therefore, a new generation of alternative solvents named natural ionic liquids and deep eutectic solvents, composed of natural and/or renewable compounds, have come into focus in recent years. Since the number of newly synthesized chemicals increases yearly, simple and reliable methods for their ecotoxicological assessment are necessary. Permanent fish cell lines can serve as a test system for the evaluation of a chemical's cytotoxicity. This paper presents research results on the cytotoxic effects on Channel Catfish Ovary (CCO) cell line induced by fifteen cholinium-based ionic liquids and deep eutectic solvents. Based on the decrease in cell viability, the most obvious toxic effect on CCO cells was caused by ionic liquid choline oxalate, while other solvents tested exhibited low cytotoxicity. Therefore, we can conclude that cholinium-based ionic liquids and deep eutectic solvents are comparatively less toxic to CCO cells than conventional ionic liquids. Copyright © 2016 Elsevier Inc. All rights reserved.

Role of Oxygen in Ionic Liquid Gating on Two-Dimensional Cr2Ge2Te6: A Non-oxide Material.

PubMed

Chen, Yangyang; Xing, Wenyu; Wang, Xirui; Shen, Bowen; Yuan, Wei; Su, Tang; Ma, Yang; Yao, Yunyan; Zhong, Jiangnan; Yun, Yu; Xie, X C; Jia, Shuang; Han, Wei

2018-01-10

Ionic liquid gating can markedly modulate a material's carrier density so as to induce metallization, superconductivity, and quantum phase transitions. One of the main issues is whether the mechanism of ionic liquid gating is an electrostatic field effect or an electrochemical effect, especially for oxide materials. Recent observation of the suppression of the ionic liquid gate-induced metallization in the presence of oxygen for oxide materials suggests the electrochemical effect. However, in more general scenarios, the role of oxygen in the ionic liquid gating effect is still unclear. Here, we perform ionic liquid gating experiments on a non-oxide material: two-dimensional ferromagnetic Cr 2 Ge 2 Te 6 . Our results demonstrate that despite the large increase of the gate leakage current in the presence of oxygen, the oxygen does not affect the ionic liquid gating effect on  the channel resistance of Cr 2 Ge 2 Te 6 devices (<5% difference), which suggests the electrostatic field effect as the mechanism on non-oxide materials. Moreover, our results show that ionic liquid gating is more effective on the modulation of the channel resistances compared to the back gating across the 300 nm thick SiO 2 .

Numerical modeling of ultrasonic cavitation in ionic liquids

NASA Astrophysics Data System (ADS)

Calvisi, Michael L.; Elder, Ross M.

2017-11-01

Ionic liquids have favorable properties for sonochemistry applications in which the high temperatures and pressures achieved by cavitation bubbles are important drivers of chemical processes. Two different numerical models are presented to simulate ultrasonic cavitation in ionic liquids, each with different capabilities and physical assumptions. A model based on a compressible form of the Rayleigh-Plesset equation (RPE) simulates ultrasonic cavitation of a spherical bubble with a homogeneous interior, incorporating evaporation and condensation at the bubble surface, and temperature-varying thermodynamic properties in the interior. A second, more computationally intensive model of a spherical bubble uses the finite element method (FEM) and accounts for spatial variations in pressure and temperature throughout the flow domain. This model provides insight into heat transfer across the bubble surface and throughout the bubble interior and exterior. Parametric studies are presented for sonochemistry applications involving ionic liquids as a solvent, examining a range of realistic ionic liquid properties and initial conditions to determine their effect on temperature and pressure. Results from the two models are presented for parametric variations including viscosity, thermal conductivity, water content of the ionic liquid solvent, acoustic frequency, and initial bubble pressure. An additional study performed with the FEM model examines thermal penetration into the surrounding ionic liquid during bubble oscillation. The results suggest the prospect of tuning ionic liquid properties for specific applications.

A Highly Aromatic and Sulfonated Ionomer for High Elastic Modulus Ionic Polymer Membrane Micro-Actuators

DTIC Science & Technology

2012-05-01

fluorophenyl)sulfone (DPA-PS:BP) is investigated for ionic polymer actuators. The uniqueness of DPA-PS:BP is that it can have a high ionic liquid (IL... ionic liquid Q M Zhang, Gokhan Hatipoglu, Yang Liu, Ran Zhao, Mitra Yoonessi, Dean M Tigelaar, Srinivas Tadigadapa Virginia Polytechnic Institute...DPA-PS:BP) is investigated for ionic polymer actuators. The uniqueness of DPA-PS:BP is that it can have a high ionic liquid (IL) uptake and

Effects of novel triple-stage antimalarial ionic liquids on lipid membrane models.

PubMed

Ferraz, Ricardo; Pinheiro, Marina; Gomes, Ana; Teixeira, Cátia; Prudêncio, Cristina; Reis, Salette; Gomes, Paula

2017-09-01

Primaquine-based ionic liquids, obtained by acid-base reaction between parent primaquine and cinnamic acids, were recently found as triple-stage antimalarial hits. These ionic compounds displayed significant activity against both liver- and blood-stage Plasmodium parasites, as well as against stage V P. falciparum parasites. Remarkably, blood-stage activity of the ionic liquids against both chloroquine-sensitive (3D7) and resistant (Dd2) P. falciparum strains was clearly superior to those of the respective covalent (amide) analogues and of parent primaquine. Having hypothesized that such behaviour might be ascribed to an enhanced ability of the ionic compounds to permeate into Plasmodium-infected erythrocytes, we have carried out a differential scanning calorimetry-based study of the interactions between the ionic liquids and membrane models. Results provide evidence, at the molecular level, that the primaquine-derived ionic liquids may contribute to an increased permeation of the parent drug into malaria-infected erythrocytes, which has relevant implications towards novel antimalarial approaches based on ionic liquids. Copyright © 2017 Elsevier Ltd. All rights reserved.

Lipid extraction from microalgae using a single ionic liquid

DOEpatents

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

2013-05-28

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

Membrane separation of ionic liquid solutions

DOEpatents

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

2015-09-01

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

Thermodynamics of interaction of ionic liquids with lipid monolayer.

PubMed

Bhattacharya, G; Mitra, S; Mandal, P; Dutta, S; Giri, R P; Ghosh, S K

2018-06-01

Understanding the interaction of ionic liquids with cellular membrane becomes utterly important to comprehend the activities of these liquids in living organisms. Lipid monolayer formed at the air-water interface is employed as a model system to follow this interaction by investigating important thermodynamic parameters. The penetration kinetics of the imidazolium-based ionic liquid 1-decyl-3-methylimidazolium tetrafluoroborate ([DMIM][BF4]) into the zwitterionic 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid layer is found to follow the Boltzmann-like equation that reveals the characteristic time constant which is observed to be the function of initial surface pressure. The enthalpy and entropy calculated from temperature-dependent pressure-area isotherms of the monolayer show that the added ionic liquids bring about a disordering effect in the lipid film. The change in Gibbs free energy indicates that an ionic liquid with longer chain has a far greater disordering effect compared to an ionic liquid with shorter chain. The differential scanning calorimetric measurement on a multilamellar vesicle system shows the main phase transition temperature to shift to a lower value, which, again, indicates the disordering effect of the ionic liquid on lipid membrane. All these studies fundamentally point out that, when ionic liquids interact with lipid molecules, the self-assembled structure of a cellular membrane gets perturbed, which may be the mechanism of these molecules having adverse effects on living organisms.

Correlation between ion diffusional motion and ionic conductivity for different electrolytes based on ionic liquid.

PubMed

Kaur, Dilraj Preet; Yamada, K; Park, Jin-Soo; Sekhon, S S

2009-04-23

Room temperature ionic liquid 2,3-dimethyl-1-hexylimidazolium bis(trifluoromethane sulfonyl)imide (DMHxImTFSI) has been synthesized and used in the preparation of polymer gel electrolytes containing polymethylmethacrylate and propylene carbonate (PC). The onset of ion diffusional motion has been studied by (1)H and (19)F NMR spectroscopy and the results obtained for ionic liquid, liquid electrolytes, and polymer gel electrolytes have been correlated with the ionic conductivity results for these electrolytes in the 100-400 K temperature range. The temperature at which (1)H and (19)F NMR lines show motional narrowing and hence ion diffusional motion starts has been found to be closely related to the temperature at which a large increase in ionic conductivity has been observed for these electrolytes. Polymer gel electrolytes have high ionic conductivity over a wide range of temperatures. Thermogravimetric analysis/differential scanning calorimetry studies show that the ionic liquid (DMHxImTFSI) used in the present study is thermally stable up to 400 degrees C, whereas the addition of PC lowers the thermal stability of polymer gel electrolytes containing the ionic liquid. Different electrolytes have been observed to show high ionic conductivity in different range of temperatures, which can be helpful in the design of polymer gel electrolytes for specific applications.

Comparative study of bending characteristics of ionic polymer actuators containing ionic liquids for modeling actuation

NASA Astrophysics Data System (ADS)

Kikuchi, Kunitomo; Sakamoto, Takumi; Tsuchitani, Shigeki; Asaka, Kinji

2011-04-01

Ionic polymer metal composites (IPMCs) that can operate in air have recently been developed by incorporating an ionic liquid in ionic polymers. To understand transduction in these composites, it is important to determine the role of the ionic liquid in the ionic polymer (Nafion®), to identify the counter cation, and to investigate the interaction of IPMCs with water vapor in the air. We used Fourier-transform infrared spectroscopy to analyze three Nafion® membranes, which were soaked in mixtures of water and an ionic liquid (1-ethyl-3-methyl-imidazolium tetrafluoroborate (EMIBF4), 1-buthyl-3-methyl-imidazolium tetrafluoroborate (BMIBF4), and 1-buthyl-3-methyl-imidazolium hexafluorophosphate (BMIPF6)). The results demonstrate that only cations (EMI+ and BMI+) in the ionic liquids are taken into the Nafion® membranes as counter ions and that the water content of the membranes in air is less than ˜4% that of Nafion® swollen with water. Based on the experimental results, a transduction model is proposed for an IPMC with an ionic liquid. In this model, bending is caused by local swelling due to the volume effect of the bulky counter cations. This model can explain 30-50% of the experimentally observed bending curvature.

Strong Stretching of Poly(ethylene glycol) Brushes Mediated by Ionic Liquid Solvation.

PubMed

Han, Mengwei; Espinosa-Marzal, Rosa M

2017-09-07

We have measured forces between mica surfaces coated with a poly(ethylene glycol) (PEG) brush solvated by a vacuum-dry ionic liquid, 1-ethyl-3-methyl imidazolium bis(trifluoromethylsulfonyl)imide, with a surface forces apparatus. At high grafting density, the solvation mediated by the ionic liquid causes the brush to stretch twice as much as in water. Modeling of the steric repulsion indicates that PEG behaves as a polyelectrolyte; the hydrogen bonding between ethylene glycol and the imidazolium cation seems to effectively charge the polymer brush, which justifies the strong stretching. Importantly, under strong polymer compression, solvation layers are squeezed out at a higher rate than for the neat ionic liquid. We propose that the thermal fluctuations of the PEG chains, larger in the brush than in the mushroom configuration, maintain the fluidity of the ionic liquid under strong compression, in contrast to the solid-like squeezing-out behavior of the neat ionic liquid. This is the first experimental study of the behavior of a polymer brush solvated by an ionic liquid under nanoconfinement.

Self-Supporting, Hydrophobic, Ionic Liquid-Based Reference Electrodes Prepared by Polymerization-Induced Microphase Separation.

PubMed

Chopade, Sujay A; Anderson, Evan L; Schmidt, Peter W; Lodge, Timothy P; Hillmyer, Marc A; Bühlmann, Philippe

2017-10-27

Interfaces of ionic liquids and aqueous solutions exhibit stable electrical potentials over a wide range of aqueous electrolyte concentrations. This makes ionic liquids suitable as bridge materials that separate in electroanalytical measurements the reference electrode from samples with low and/or unknown ionic strengths. However, methods for the preparation of ionic liquid-based reference electrodes have not been explored widely. We have designed a convenient and reliable synthesis of ionic liquid-based reference electrodes by polymerization-induced microphase separation. This technique allows for a facile, single-pot synthesis of ready-to-use reference electrodes that incorporate ion conducting nanochannels filled with either 1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide or 1-dodecyl-3-methylimidazolium bis(trifluoromethyl sulfonyl)imide as ionic liquid, supported by a mechanically robust cross-linked polystyrene phase. This synthesis procedure allows for the straightforward design of various reference electrode geometries. These reference electrodes exhibit a low resistance as well as good reference potential stability and reproducibility when immersed into aqueous solutions varying from deionized, purified water to 100 mM KCl, while requiring no correction for liquid junction potentials.

Influence of Polar Organic Solvents in an Ionic Liquid Containing Lithium Bis(fluorosulfonyl)amide: Effect on the Cation-Anion Interaction, Lithium Ion Battery Performance, and Solid Electrolyte Interphase.

PubMed

Lahiri, Abhishek; Li, Guozhu; Olschewski, Mark; Endres, Frank

2016-12-14

Ionic liquid-organic solvent mixtures have recently been investigated as potential battery electrolytes. However, contradictory results with these mixtures have been shown for battery performance. In this manuscript, we studied the influence of the addition of polar organic solvents into the ionic liquid electrolyte 1 M lithium bis(fluorosulfonyl)amide (LiFSI)-1-butyl-1-methylpyrrolidinium bis(fluorosulfonyl)amide ([Py 1,4 ]FSI) and tested it for lithium ion battery applications. From infrared and Raman spectroscopy, clear changes in the lithium solvation and cation-anion interactions in the ionic liquid were observed on addition of organic solvents. From the lithiation/delithiation studies on electrodeposited Ge, the storage capacity for the ionic liquid-highly polar organic solvent (acetonitrile) mixture was found to be the highest at low C-rates (0.425 C) compared to using an ionic liquid alone and ionic liquid-less polar solvent (dimethyl carbonate) mixtures. Furthermore, XPS and AFM were used to evaluate the solid electrolyte interphase (SEI) and to correlate its stability with Li storage capacity.

Determination of metal ions in tea samples using task-specific ionic liquid-based ultrasound-assisted dispersive liquid-liquid microextraction coupled to liquid chromatography with ultraviolet detection.

PubMed

Werner, Justyna

2016-04-01

Task-specific ionic liquid-based ultrasound-assisted dispersive liquid-liquid microextraction was used for the preconcentration of cadmium(II), cobalt(II), and lead(II) ions in tea samples, which were subsequently analyzed by liquid chromatography with UV detection. The proposed method of preconcentration is free of volatile organic compounds, which are often used as extractants and dispersing solvents in classic techniques of microextraction. A task-specific ionic liquid trioctylmethylammonium thiosalicylate was used as an extractant and a chelating agent. Ultrasound was used to disperse the ionic liquid. After microextraction, the phases were separated by centrifugation, and the ionic liquid phase was solubilized in methanol and directly injected into the liquid chromatograph. Selected microextraction parameters, such as the volume of ionic liquid, the pH of the sample, the duration of ultrasound treatment, the speed and time of centrifugation, and the effect of ionic strength, were optimized. Under optimal conditions an enrichment factor of 200 was obtained for each analyte. The limits of detection were 0.002 mg/kg for Cd(II), 0.009 mg/kg for Co(II), and 0.013 mg/kg for Pb(II). The accuracy of the proposed method was evaluated by an analysis of the Certified Reference Materials (INCT-TL-1, INCT-MPH-2) with the recovery values in the range of 90-104%. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Probing the interaction of ionic liquids with graphene using surface-enhanced Raman spectroscopy

DOE PAGES

Mahurin, Shannon Mark; Dai, Sheng; Surwade, Sumedh P.; ...

2015-12-17

We report an in situ measurement of the interaction of an imidazolium-based room temperature ionic liquid with both pure silver and a graphene-over-silver electrode under an applied electrochemical potential. At a negative applied potential, overall signal intensity increased indicating enhanced ionic liquid concentration at both silver and graphene electrodes. Vibrational modes associated with the imidazolium ring exhibited greater intensity enhancements and larger peak shifts compared with the anion indicating that the cation adsorbs with the ring and alkyl chain parallel to the electrode surface for both silver and graphene. In contrast to the silver, the surface enhanced Raman spectra ofmore » the ionic liquid near graphene showed shifts in the cation peaks even at no applied potential because of the strong π–π interaction between the ionic liquid and the graphene. Furthermore, the intensity of the graphene peak decreased in the presence of ionic liquid possibly due to the interaction between the ionic liquid and graphene. In conclusion, these results illustrate the effectiveness of surface-enhanced Raman spectroscopy to investigate electrolyte interactions with graphene at the liquid/electrode interface.« less

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

PubMed Central

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

2013-01-01

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

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

PubMed

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

2016-07-14

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

X‐ray Photoelectron Spectroscopy of Pyridinium‐Based Ionic Liquids: Comparison to Imidazolium‐ and Pyrrolidinium‐Based Analogues

PubMed Central

Mitchell, Daniel S.; Lovelock, Kevin R. J.

2015-01-01

Abstract We investigate eight 1‐alkylpyridinium‐based ionic liquids of the form [CnPy][A] by using X‐ray photoelectron spectroscopy (XPS). The electronic environment of each element of the ionic liquids is analyzed. In particular, a reliable fitting model is developed for the C 1s region that applies to each of the ionic liquids. This model allows the accurate charge correction of binding energies and the determination of reliable and reproducible binding energies for each ionic liquid. Shake‐up/off phenomena are determinedfor both C 1s and N 1s spectra. The electronic interaction between cations and anions is investigated for both simple ionic liquids and an example of an ionic‐liquid mixture; the effect of the anion on the electronic environment of the cation is also explored. Throughout the study, a detailed comparison is made between [C8Py][A] and analogues including 1‐octyl‐1‐methylpyrrolidinium‐ ([C8C1Pyrr][A]), and 1‐octyl‐3‐methylimidazolium‐ ([C8C1Im][A]) based samples, where X is common to all ionic liquids. PMID:25952131

Ionic Liquids in Polymer Design: From Energy to Health

DTIC Science & Technology

2016-10-19

SECURITY CLASSIFICATION OF: ACS Symposium: Ionic Liquids in Polymer Design: From Energy to Health at Fall 2015 ACS Meeting in Boston, MA The...combination of ionic liquids and polymers has emerged as an active field of exploration in polymer science, where new materials have be realized for...2016 Final Report: Ionic Liquids in Polymer Design: From Energy to Health The views, opinions and/or findings contained in this report are those of

Kinetic Studies of Reactions in Solution Using Fast Mass Spectrometry

DTIC Science & Technology

2013-08-13

dicyanamide ionic liquids Hypergolic fuels, or hypergols, can be ignited by exposure to an oxidizing agent under ambient conditions and are a common...DCA) based ionic liquids are a less volatile alternative that are less viscous than most ionic liquids ; however, ignition of these compounds...Condensates upon Hypergolic Ignition of Dicyanamide Ionic Liquids ," Angew. Chem. Int. Ed. 50, 8634–8637 (2011). (7) R. H. Perry, D. I. Bellovin, E

Catalytic Decomposition of Hydroxylammonium Nitrate Ionic Liquid: Enhancement of NO Formation

DTIC Science & Technology

2017-04-24

Nitrate Ionic Liquid : Enhancement of NO Formation Steven D. Chambreau, Denisia M. Popolan-Vaida, Ghanshyam L. Vaghjiani, and Stephen R. Leone Air Force...Hydroxylammonium Nitrate Ionic Liquid : Enhancement of NO Formation Steven D. Chambreau,† Denisia M. Popolan-Vaida,‡,§ Ghanshyam L. Vaghjiani,*,∥ and Stephen R...nitrate (HAN)ionic liquid as a replacement for hydrazine as a spacecraft monopropellant has been of great interest recently due to the reduced toxicity

A simulation study of CS2 solutions in two related ionic liquids with dications and monocations

NASA Astrophysics Data System (ADS)

Lynden-Bell, R. M.; Quitevis, E. L.

2018-05-01

Atomistic simulations of solutions of CS2 in an ionic liquid, [C8(C1im)2 ] [NTf2]2, with a divalent cation and in the corresponding ionic liquid with a monovalent cation, [C4C1im][NTf2], were carried out. The low-frequency librational density of states of the CS2 was of particular interest in view of recent optical heterodyne-detected Raman-induced Kerr effect spectroscopy (OHD-RIKES). Compared to the monocation ionic liquid, the maximum shifts to higher frequencies in the dication ionic liquid under ambient conditions, but was found to be significantly pressure-dependent. CS2 molecules lie above and below the plane of the imidazolium rings and found to be close to the butyl tails of the monocation. The diffusion rates and embedding energies of solvent ions and CS2 in the two ionic liquids were measured.

A physicochemical investigation of ionic liquid mixtures† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c4sc02931c Click here for additional data file.

PubMed Central

Clough, Matthew T.; Crick, Colin R.; Gräsvik, John; Niedermeyer, Heiko; Whitaker, Oliver P.

2015-01-01

Ionic liquids have earned the reputation of being ‘designer solvents’ due to the wide range of accessible properties and the degree of fine-tuning afforded by varying the constituent ions. Mixtures of ionic liquids offer the opportunity for further fine-tuning of properties. A broad selection of common ionic liquid cations and anions are employed to create a sample of binary and reciprocal binary ionic liquid mixtures, which are analysed and described in this paper. Physical properties such as the conductivity, viscosity, density and phase behaviour (glass transition temperatures) are examined. In addition, thermal stabilities of the mixtures are evaluated. The physical properties examined for these formulations are found to generally adhere remarkably closely to ideal mixing laws, with a few consistent exceptions, allowing for the facile prediction and control of properties of ionic liquid mixtures. PMID:29560198

Effect of ionic liquid on activity, stability, and structure of enzymes: a review.

PubMed

Naushad, Mu; Alothman, Zied Abdullah; Khan, Abbul Bashar; Ali, Maroof

2012-11-01

Ionic liquids have shown their potential as a solvent media for many enzymatic reactions as well as protein preservation, because of their unusual characteristics. It is also observed that change in cation or anion alters the physiochemical properties of the ionic liquids, which in turn influence the enzymatic reactions by altering the structure, activity, enatioselectivity, and stability of the enzymes. Thus, it is utmost need of the researchers to have full understanding of these influences created by ionic liquids before choosing or developing an ionic liquid to serve as solvent media for enzymatic reaction or protein preservation. So, in the present review, we try to shed light on effects of ionic liquids chemistry on structure, stability, and activity of enzymes, which will be helpful for the researchers in various biocatalytic applications. Copyright © 2012. Published by Elsevier B.V.

Ionic-liquid materials for the electrochemical challenges of the future.

PubMed

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

2009-08-01

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.

Ionic liquids and their solid-state analogues as materials for energy generation and storage

NASA Astrophysics Data System (ADS)

Macfarlane, Douglas R.; Forsyth, Maria; Howlett, Patrick C.; Kar, Mega; Passerini, Stefano; Pringle, Jennifer M.; Ohno, Hiroyuki; Watanabe, Masayoshi; Yan, Feng; Zheng, Wenjun; Zhang, Shiguo; Zhang, Jie

2016-02-01

Salts that are liquid at room temperature, now commonly called ionic liquids, have been known for more than 100 years; however, their unique properties have only come to light in the past two decades. In this Review, we examine recent work in which the properties of ionic liquids have enabled important advances to be made in sustainable energy generation and storage. We discuss the use of ionic liquids as media for synthesis of electromaterials, for example, in the preparation of doped carbons, conducting polymers and intercalation electrode materials. Focusing on their intrinsic ionic conductivity, we examine recent reports of ionic liquids used as electrolytes in emerging high-energy-density and low-cost batteries, including Li-ion, Li-O2, Li-S, Na-ion and Al-ion batteries. Similar developments in electrolyte applications in dye-sensitized solar cells, thermo-electrochemical cells, double-layer capacitors and CO2 reduction are also discussed.

Ionic-liquid materials for the electrochemical challenges of the future

NASA Astrophysics Data System (ADS)

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

2009-08-01

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.

Corrosion Inhibition of Cast Iron in Arabian Gulf Seawater by Two Different Ionic Liquids

PubMed Central

Sherif, El-Sayed M.; Abdo, Hany S.; Zein El Abedin, Sherif

2015-01-01

In this paper we report on the corrosion inhibition of cast iron in Arabian Gulf seawater by two different ionic liquids namely, 1-ethyl-3-methylimidazolium chloride ([EMIm]Cl) and 1-butyl-1-methylpyrrolidinium chloride ([Py1,4]Cl). The inhibiting influence of the employed ionic liquids was investigated by weight loss, open circuit potential electrochemical impedance spectroscopy, and cyclic potentiodynamic polarization. The results show the corrosion inhibition impact of the employed ionic liquids (ILs). Compared with [Py1,4]Cl, [EMIm]Cl shows a higher inhibition efficiency at a short immersion time, for the examined ILs concentrations. However, [Py1,4]Cl exhibits a higher efficiency upon increasing the immersion time indicating the persistence of the inhibiting influence. The corrosion inhibition of the employed ionic liquids is attributed to the adsorption of the cations of the ionic liquids onto the surface of cast iron forming a corrosion barrier. PMID:28793413

Interactions between water and 1-butyl-1-methylpyrrolidinium ionic liquids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fadeeva, Tatiana A.; DeVine, Jessalyn A.; Castner, Edward W., E-mail: ed.castner@rutgers.edu

2015-08-14

We report experimental results on the diffusivity of water in two ionic liquids obtained using the pulsed-gradient spin-echo NMR method. Both ionic liquids have the same cation, 1-butyl-1-methylpyrrolidinium, but different trifluoromethyl-containing anions. One has a strongly hydrophobic anion, bis(trifluoromethylsulfonyl)amide, while the second has a hydrophilic anion, trifluoromethylsulfonate. Transport of water in these ionic liquids is much faster than would be predicted from hydrodynamic laws, indicating that the neutral water molecules experience a very different friction than the anions and cations at the molecular level. Temperature-dependent viscosities, conductivities, and densities are reported as a function of water concentration to further analyzemore » the properties of the ionic liquid-water mixtures. These results on the properties of water in ionic liquids should be of interest to researchers in diverse areas ranging from separations, solubilizing biomass and energy technologies.« less

Ionic liquid as an electrolyte additive for high performance lead-acid batteries

NASA Astrophysics Data System (ADS)

Deyab, M. A.

2018-06-01

The performance of lead-acid battery is improved in this work by inhibiting the corrosion of negative battery electrode (lead) and hydrogen gas evolution using ionic liquid (1-ethyl-3-methylimidazolium diethyl phosphate). The results display that the addition of ionic liquid to battery electrolyte (5.0 M H2SO4 solution) suppresses the hydrogen gas evolution to very low rate 0.049 ml min-1 cm-2 at 80 ppm. Electrochemical studies show that the adsorption of ionic liquid molecules on the lead electrode surface leads to the increase in the charge transfer resistance and the decrease in the double layer capacitance. I also notice a noteworthy improvement of battery capacity from 45 mAh g-1 to 83 mAh g-1 in the presence of ionic liquid compound. Scanning electron microscopy and energy dispersive X-ray analysis confirm the adsorption of ionic liquid molecules on the battery electrode surface.

Composites of ionic liquid and amine-modified SAPO 34 improve CO2 separation of CO2-selective polymer membranes

NASA Astrophysics Data System (ADS)

Hu, Leiqing; Cheng, Jun; Li, Yannan; Liu, Jianzhong; Zhang, Li; Zhou, Junhu; Cen, Kefa

2017-07-01

Mixed matrix membranes with ionic liquids and molecular sieve particles had high CO2 permeabilities, but CO2 separation from small gas molecules such as H2 was dissatisfied because of bad interfacial interaction between ionic liquid and molecular sieve particles. To solve that, amine groups were introduced to modify surface of molecular sieve particles before loading with ionic liquid. SAPO 34 was adopted as the original filler, and four mixed matrix membranes with different fillers were prepared on the outer surface of ceramic hollow fibers. Both surface voids and hard agglomerations disappeared, and the surface became smooth after SAPO 34 was modified by amine groups and ionic liquid [P66614][2-Op]. Mixed matrix membranes with composites of amine-modified SAPO 34 and ionic liquid exhibited excellent CO2 permeability (408.9 Barrers) and CO2/H2 selectivity (22.1).

Thermal boundary conductance of hydrophilic and hydrophobic ionic liquids

NASA Astrophysics Data System (ADS)

Oyake, Takafumi; Sakata, Masanori; Yada, Susumu; Shiomi, Junichiro

2015-03-01

A solid/liquid interface plays a critical role for understanding mechanisms of biological and physical science. Moreover, carrier density of the surface is dramatically enhanced by electric double layer with ionic liquid, salt in the liquid state. Here, we have measured the thermal boundary conductance (TBC) across an interface of gold thin film and ionic liquid by using time-domain thermoreflectance technique. Following the prior researches, we have identified the TBC of two interfaces. One is gold and hydrophilic ionic liquid, N,N-Diethyl-N-methyl-N-(2-methoxyethyl) ammonium tetrafluoroborate (DEME-BF4), which is a hydrophilic ionic liquid, and the other is N,N-Diethyl-N-methyl-N-(2-methoxyethyl) ammonium bis (trifluoromethanesulfonyl) imide (DEME-TFSI), which is a hydrophobic ionic liquid. We found that the TBC between gold and DEME-TFIS (19 MWm-2K-1) is surprisingly lower than the interface between gold and DEME-BF4 (45 MWm-2K-1). With these data, the importance of the wetting angle and ion concentration for the thermal transport at the solid/ionic liquid interface is discussed. Part of this work is financially supported by Japan Society for the Promotion of Science (JSPS) and Japan Science and Technology Agency. The author is financially supported by JSPS Fellowship.

Charge Transport and Phase Behavior of Imidazolium-Based Ionic Liquid Crystals from Fully Atomistic Simulations

PubMed Central

2018-01-01

Ionic liquid crystals occupy an intriguing middle ground between room-temperature ionic liquids and mesostructured liquid crystals. Here, we examine a non-polarizable, fully atomistic model of the 1-alkyl-3-methylimidazolium nitrate family using molecular dynamics in the constant pressure–constant temperature ensemble. These materials exhibit a distinct “smectic” liquid phase, characterized by layers formed by the molecules, which separate the ionic and aliphatic moieties. In particular, we discuss the implications this layering may have for electrolyte applications. PMID:29301305

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...

Molecular dynamics simulation of polymer electrolytes based on poly(ethylene oxide) and ionic liquids. I. Structural properties.

PubMed

Costa, Luciano T; Ribeiro, Mauro C C

2006-05-14

Molecular dynamics (MD) simulations have been performed for prototype models of polymer electrolytes in which the salt is an ionic liquid based on 1-alkyl-3-methylimidazolium cations and the polymer is poly(ethylene oxide), PEO. The MD simulations were performed by combining the previously proposed models for pure ionic liquids and polymer electrolytes containing simple inorganic ions. A systematic investigation of ionic liquid concentration, temperature, and the 1-alkyl- chain length, [1,3-dimethylimidazolium]PF6, and [1-butyl-3-methylimidazolium]PF6, effects on resulting equilibrium structure is provided. It is shown that the ionic liquid is dispersed in the polymeric matrix, but ionic pairs remain in the polymer electrolyte. Imidazolium cations are coordinated by both the anions and the oxygen atoms of PEO chains. Probability density maps of occurrences of nearest neighbors around imidazolium cations give a detailed physical picture of the environment experienced by cations. Conformational changes on PEO chains upon addition of the ionic liquid are identified. The equilibrium structure of simulated systems is also analyzed in reciprocal space by using the static structure factor, S(k). Calculated S(k) display a low wave-vector peak, indicating that spatial correlation in an extended-range order prevail in the ionic liquid polymer electrolytes. Long-range correlations are assigned to nonuniform distribution of ionic species within the simulation box.

Extraction of organic compounds with room temperature ionic liquids.

PubMed

Poole, Colin F; Poole, Salwa K

2010-04-16

Room temperature ionic liquids are novel solvents with a rather specific blend of physical and solution properties that makes them of interest for applications in separation science. They are good solvents for a wide range of compounds in which they behave as polar solvents. Their physical properties of note that distinguish them from conventional organic solvents are a negligible vapor pressure, high thermal stability, and relatively high viscosity. They can form biphasic systems with water or low polarity organic solvents and gases suitable for use in liquid-liquid and gas-liquid partition systems. An analysis of partition coefficients for varied compounds in these systems allows characterization of solvent selectivity using the solvation parameter model, which together with spectroscopic studies of solvent effects on probe substances, results in a detailed picture of solvent behavior. These studies indicate that the solution properties of ionic liquids are similar to those of polar organic solvents. Practical applications of ionic liquids in sample preparation include extractive distillation, aqueous biphasic systems, liquid-liquid extraction, liquid-phase microextraction, supported liquid membrane extraction, matrix solvents for headspace analysis, and micellar extraction. The specific advantages and limitations of ionic liquids in these studies is discussed with a view to defining future uses and the need not to neglect the identification of new room temperature ionic liquids with physical and solution properties tailored to the needs of specific sample preparation techniques. The defining feature of the special nature of ionic liquids is not their solution or physical properties viewed separately but their unique combinations when taken together compared with traditional organic solvents. Copyright 2009 Elsevier B.V. All rights reserved.

Ionic Liquid Crystals: Versatile Materials.

PubMed

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

2016-04-27

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

Rare earth metal-containing ionic liquids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prodius, Denis; Mudring, Anja-Verena

As an innovative tool, ionic liquids (ILs) are widely employed as an alternative, smart, reaction media (vs. traditional solvents) offering interesting technology solutions for dissolving, processing and recycling of metal-containing materials. The costly mining and refining of rare earths (RE), combined with increasing demand for high-tech and energy-related applications around the world, urgently requires effective approaches to improve the efficiency of rare earth separation and recovery. In this context, ionic liquids appear as an attractive technology solution. Finally, this paper addresses the structural and coordination chemistry of ionic liquids comprising rare earth metals with the aim to add to understandingmore » prospects of ionic liquids in the chemistry of rare earths.« less

Rare earth metal-containing ionic liquids

DOE PAGES

Prodius, Denis; Mudring, Anja-Verena

2018-03-07

As an innovative tool, ionic liquids (ILs) are widely employed as an alternative, smart, reaction media (vs. traditional solvents) offering interesting technology solutions for dissolving, processing and recycling of metal-containing materials. The costly mining and refining of rare earths (RE), combined with increasing demand for high-tech and energy-related applications around the world, urgently requires effective approaches to improve the efficiency of rare earth separation and recovery. In this context, ionic liquids appear as an attractive technology solution. Finally, this paper addresses the structural and coordination chemistry of ionic liquids comprising rare earth metals with the aim to add to understandingmore » prospects of ionic liquids in the chemistry of rare earths.« less

Properties of the Nafion membrane impregnated with hydroxyl ammonium based ionic liquids

NASA Astrophysics Data System (ADS)

Garaev, Valeriy; Kleperis, Janis; Pavlovica, Sanita; Vaivars, Guntars

2012-08-01

In this work, the Nafion 112 membrane impregnated with nine various hydroxyl ammonium based ionic liquids have been investigated. The used ionic liquids were combined from hydroxyl ammonium cations (2-hydroxyethylammonium/HEA, bis(2- hydroxyethyl)ammonium/BHEA, tris(2-hydroxyethyl)ammonium/THEA) and carboxylate anions (formate, acetate, lactate). The membranes are characterized by conductivity and thermal stability measurements. It was found, that almost all composites have 10 times higher ion conductivity than a pure Nafion 112 at 90 °C in ambient environment due to the higher thermal stability. The thermal stability of Nafion membrane was increased by all studied nine ionic liquids. In this work, only biodegradable ionic liquids were used for composite preparation.

Tube Radial Distribution Flow Separation in a Microchannel Using an Ionic Liquid Aqueous Two-Phase System Based on Phase Separation Multi-Phase Flow.

PubMed

Nagatani, Kosuke; Shihata, Yoshinori; Matsushita, Takahiro; Tsukagoshi, Kazuhiko

2016-01-01

Ionic liquid aqueous two-phase systems were delivered into a capillary tube to achieve tube radial distribution flow (TRDF) or annular flow in a microspace. The phase diagram, viscosity of the phases, and TRDF image of the 1-butyl-3-methylimidazolium chloride and NaOH system were examined. The TRDF was formed with inner ionic liquid-rich and outer ionic liquid-poor phases in the capillary tube. The phase configuration was explained using the viscous dissipation principle. We also examined the distribution of rhodamine B in a three-branched microchannel on a microchip with ionic liquid aqueous two-phase systems for the first time.

Isolation and Characterisation of 1-Alkyl-3-Methylimidazolium Chloride Ionic Liquid-Tolerant and Biodegrading Marine Bacteria

PubMed Central

Megaw, Julianne; Busetti, Alessandro; Gilmore, Brendan F.

2013-01-01

The aim of this study was to isolate and identify marine-derived bacteria which exhibited high tolerance to, and an ability to biodegrade, 1-alkyl-3-methylimidazolium chloride ionic liquids. The salinity and hydrocarbon load of some marine environments may induce selective pressures which enhance the ability of microbes to grow in the presence of these liquid salts. The isolates obtained in this study generally showed a greater ability to grow in the presence of the selected ionic liquids compared to microorganisms described previously, with two marine-derived bacteria, Rhodococcus erythropolis and Brevibacterium sanguinis growing in concentrations exceeding 1 M 1-ethyl-3-methylimidazolium chloride. The ability of these bacteria to degrade the selected ionic liquids was assessed using High Performance Liquid Chromatography (HPLC), and three were shown to degrade the selected ionic liquids by up to 59% over a 63-day test period. These bacterial isolates represent excellent candidates for further potential applications in the bioremediation of ionic liquid-containing waste or following accidental environmental exposure. PMID:23560109

Thermal Decomposition Mechanisms of Alkylimidazolium Ionic Liquids with CN-containing Anions

DTIC Science & Technology

2014-11-01

anion calculated at the M06/6-31+G(d,p) level of theory and using the generic ionic liquid (GIL) model to simulate the condensed phase methyl...decomposition mechanisms of alkylimidazolium ionic liquids with CN-containing anions 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d...perform, display, or disclose the work. 14. ABSTRACT Due to the unusually high heats of vaporization of room-temperature ionic liquids (RTILs

Development of the Electrochemical Biosensor for Organophosphate Chemicals Using CNT/Ionic Liquid Bucky Gel Electrode

DTIC Science & Technology

2010-04-01

www.elsevier .com/locate /e lecomDevelopment of the electrochemical biosensor for organophosphate chemicals using CNT/ ionic liquid bucky gel electrode Bong...hydrolase Ionic liquid CNT Electrochemical property1388-2481/$ - see front matter 2009 Elsevier B.V. A doi:10.1016/j.elecom.2009.01.006 * Corresponding...kaist.ac.kr (S.Y. Lee), whhOrganophosphorus hydrolase (OPH) immobilized on CNT/ ionic liquid (IL) electrodes were prepared by using three different intrinsic

β-cyclodextrin-ionic liquid polymer based dynamically coating for simultaneous determination of tetracyclines by capillary electrophoresis.

PubMed

Zhou, Chunyan; Deng, Jingjing; Shi, Guoyue; Zhou, Tianshu

2017-04-01

Tetracyclines are a group of broad spectrum antibiotics widely used in animal husbandry to prevent and treat diseases. However, the improper use of tetracyclines may result in the presence of their residues in animal tissues or waste. Recently, great attention has been drawn towards the green solvents ionic liquids. Ionic liquids have been employed as a coating material to modify the electroosmotic flow in capillary electrophoresis. In this study, a functionalized ionic liquid, mono-6-deoxy-6-(3-methylimidazolium)-β-cyclodextrin tosylate, was synthesized and used for the simultaneous separation and quantification of tetracyclines by capillary electrophoresis. Good separation efficiency could be achieved due to the multiple functions of β-cyclodextrin derived ionic liquid, including the electrostatic interaction, the hydrogen bonding, and the cavity structure in β-cyclodextrin ionic liquid which can entrap the tetracyclines to form inclusion complex. After optimization, baseline separation achieved in 25 min with the running buffer consisted of 10 mmol/L, pH 7.2 phosphate buffer and 20 mmol/L β-cyclodextrin ionic liquid. The satisfied result demonstrated that the β-cyclodextrin ionic liquid is an ideal background electrolyte modifier in the separation of tetracyclines with high stability and good reproducibility. And it is an effective strategy to design and synthesize specific ILs as additive applied in separation. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Natural terpene derivatives as new structural task-specific ionic liquids to enhance the enantiorecognition of acidic enantiomers on teicoplanin-based stationary phase by high-performance liquid chromatography.

PubMed

Flieger, Jolanta; Feder-Kubis, Joanna; Tatarczak-Michalewska, Małgorzata; Płazińska, Anita; Madejska, Anna; Swatko-Ossor, Marta

2017-06-01

We present the specific cooperative effect of a semisynthetic glycopeptide antibiotic teicoplanin and chiral ionic liquids containing the (1R,2S,5R)-(-)-menthol moiety on the chiral recognition of enantiomers of mandelic acid, vanilmandelic acid, and phenyllactic acid. Experiments were performed chromatographically on an Astec Chirobiotic T chiral stationary phase applying the mobile phase with the addition of the chiral ionic liquids. The stereoselective binding of enantiomers to teicoplanin in presence of new chiral ionic liquids were evaluated applying thermodynamic measurements and the docking simulations. Both the experimental and theoretical methods revealed that the chiral recognition of enantiomers in the presence of new chiral ionic liquids was enthalpy driven. The changes of the teicoplanin conformation occurring upon binding of the chiral ionic liquids are responsible for the differences in the standard changes in Gibbs energy (ΔG 0 ) values obtained for complexes formed by the R and S enantiomers and teicoplanin. Docking simulations revealed the steric adjustment between the chiral ionic liquids cyclohexane ring (chair conformation) and the β-d-glucosamine ring of teicoplanin and additionally hydrophobic interactions between the decanoic aliphatic chain of teicoplanin and the alkyl group of the tested salts. The obtained terpene derivatives can be considered as "structural task-specific ionic liquids" responsible for enhancing the chiral resolution in synergistic systems with two chiral selectors. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nanoscale Ionic Liquids

DTIC Science & Technology

2006-11-01

Technical Report 11 December 2005 - 30 November 2006 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Nanoscale Ionic Liquids 5b. GRANT NUMBER FA9550-06-1-0012...Title: Nanoscale Ionic Liquids Principal Investigator: Emmanuel P. Giannelis Address: Materials Science and Engineering, Bard Hall, Cornell University...based fluids exhibit high ionic conductivity. The NFs are typically synthesized by grafting a charged, oligomeric corona onto the nanoparticle cores

Synthesis of hetero ionic compounds using dialkylcarbonate quaternization

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

2017-09-19

Methods of preparing hetero ionic complexes, and ionic liquids from bisulfate salts of heteroatomic compounds using dialkylcarbonates as a primary quaternizing reactant are disclosed. Also disclosed are methods of making electrochemical cells comprising the ionic liquids, and an electrochemical cell comprising an alkaline electrolyte and a hetero ionic complex additive.

Synthesis of hetero ionic compounds using dialkylcarbonate quaternization

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

2018-04-03

Methods of preparing hetero ionic complexes, and ionic liquids from bisulfate salts of heteroatomic compounds using dialkylcarbonates as a primary quaternizing reactant are disclosed. Also disclosed are methods of making electrochemical cells comprising the ionic liquids, and an electrochemical cell comprising an alkaline electrolyte and a hetero ionic complex additive.

Determination of the distribution constants of aromatic compounds and steroids in biphasic micellar phosphonium ionic liquid/aqueous buffer systems by capillary electrokinetic chromatography.

PubMed

Lokajová, Jana; Railila, Annika; King, Alistair W T; Wiedmer, Susanne K

2013-09-20

The distribution constants of some analytes, closely connected to the petrochemical industry, between an aqueous phase and a phosphonium ionic liquid phase, were determined by ionic liquid micellar electrokinetic chromatography (MEKC). The phosphonium ionic liquids studied were the water-soluble tributyl(tetradecyl)phosphonium with chloride or acetate as the counter ion. The retention factors were calculated and used for determination of the distribution constants. For calculating the retention factors the electrophoretic mobilities of the ionic liquids were required, thus, we adopted the iterative process, based on a homologous series of alkyl benzoates. Calculation of the distribution constants required information on the phase-ratio of the systems. For this the critical micelle concentrations (CMC) of the ionic liquids were needed. The CMCs were calculated using a method based on PeakMaster simulations, using the electrophoretic mobilities of system peaks. The resulting distribution constants for the neutral analytes between the ionic liquid and the aqueous (buffer) phase were compared with octanol-water partitioning coefficients. The results indicate that there are other factors affecting the distribution of analytes between phases, than just simple hydrophobic interactions. Copyright © 2013 Elsevier B.V. All rights reserved.

Influence of the ionic liquid 1-butyl-3-methylimidazolium bromide on amyloid fibrillogenesis in lysozyme: Evidence from photophysical and imaging studies.

PubMed

Basu, Anirban; Bhattacharya, Subhash Chandra; Kumar, Gopinatha Suresh

2018-02-01

Many proteins can abnormally fold to form pathological amyloid deposits/aggregates that are responsible for various degenerative disorders called amyloidosis. Here we have examined the anti-amyloidogenic potency of an ionic liquid, 1-butyl-3-methylimidazolium bromide, using lysozyme as a model system. Thioflavin T fluorescence assay demonstrated that the ionic liquid suppressed the formation of lysozyme fibrils significantly. This observation was further confirmed by the Congo red assay. Fluorescence microscopy, intrinsic fluorescence studies, nile red fluorescence assay, ANS binding assay and circular dichroism studies also testified diminishing of the fibrillogenesis in the presence of ionic liquid. Formation of amyloid fibrils was also characterized by α to β conformational transition. From far-UV circular dichroism studies it was observed that the β-sheet content of the lysozyme samples decreased in the presence of the ionic liquid which in turn implied that fibrillogenesis was supressed by the ionic liquid. Atomic force microscopy imaging unequivocally established that the ionic liquid attenuated fibrillogenesis in lysozyme. These results may be useful for the development of more effective therapeutics for amyloidosis. Copyright © 2017 Elsevier B.V. All rights reserved.

Self-Supporting, Hydrophobic, Ionic Liquid-Based Reference Electrodes Prepared by Polymerization-Induced Microphase Separation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chopade, Sujay A.; Anderson, Evan L.; Schmidt, Peter W.

Interfaces of ionic liquids and aqueous solutions exhibit stable electrical potentials over a wide range of aqueous electrolyte concentrations. This makes ionic liquids suitable as bridge materials that separate in electroanalytical measurements the reference electrode from samples with low and/or unknown ionic strengths. However, methods for the preparation of ionic liquid-based reference electrodes have not been explored widely. We have designed a convenient and reliable synthesis of ionic liquid-based reference electrodes by polymerization-induced microphase separation. This technique allows for a facile, single-pot synthesis of ready-to-use reference electrodes that incorporate ion conducting nanochannels filled with either 1-octyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide or 1-dodecyl-3-methylimidazolium bis(trifluoromethylmore » sulfonyl)imide as ionic liquid, supported by a mechanically robust cross-linked polystyrene phase. This synthesis procedure allows for the straightforward design of various reference electrode geometries. These reference electrodes exhibit a low resistance as well as good reference potential stability and reproducibility when immersed into aqueous solutions varying from deionized, purified water to 100 mM KCl, while requiring no correction for liquid junction potentials.« less

Harnessing Poly(ionic liquid)s for Sensing Applications.

PubMed

Guterman, Ryan; Ambrogi, Martina; Yuan, Jiayin

2016-07-01

The interest in poly(ionic liquid)s for sensing applications is derived from their strong interactions to a variety of analytes. By combining the desirable mechanical properties of polymers with the physical and chemical properties of ILs, new materials can be created. The tunable nature of both ionic liquids and polymers allows for incredible diversity, which is exemplified in their broad applicability. In this article we examine the new field of poly(ionic liquid) sensors by providing a detailed look at the current state-of-the-art sensing devices for solvents, gases, biomolecules, pH, and anions. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Novel applications of ionic liquids in materials processing

NASA Astrophysics Data System (ADS)

Reddy, Ramana G.

2009-05-01

Ionic liquids are mixtures of organic and inorganic salts which are liquids at room temperature. Several potential applications of ionic liquids in the field of materials processing are electrowinning and electrodeposition of metals and alloys, electrolysis of active metals at low temperature, liquid-liquid extraction of metals. Results using 1-butyl-3-methylimidazolium chloride with AlCl3 at low temperatures yielded high purity aluminium deposits (>99.9% pure) and current efficiencies >98%. Titanium and aluminium were co-deposited with/without the addition of TiCl4 with up to 27 wt% Ti in the deposit with current efficiencies in the range of 78-85 %. Certain ionic liquids are potential replacements for thermal oils and molten salts as heat transfer fluids in solar energy applications due to high thermal stability, very low corrosivity and substantial sensible heat retentivity. The calculated storage densities for several chloride and fluoride ionic liquids are in the range of 160-210 MJ/m3. A 3-D mathematical model was developed to simulate the large scale electrowinning of aluminium. Since ionic liquids processing results in their low energy consumption, low pollutant emissions many more materials processing applications are expected in future.

Metal-air cell with performance enhancing additive

DOEpatents

Friesen, Cody A; Buttry, Daniel

2015-11-10

Systems and methods drawn to an electrochemical cell comprising a low temperature ionic liquid comprising positive ions and negative ions and a performance enhancing additive added to the low temperature ionic liquid. The additive dissolves in the ionic liquid to form cations, which are coordinated with one or more negative ions forming ion complexes. The electrochemical cell also includes an air electrode configured to absorb and reduce oxygen. The ion complexes improve oxygen reduction thermodynamics and/or kinetics relative to the ionic liquid without the additive.

Nanoarchitecture Control Enabled by Ionic Liquids

NASA Astrophysics Data System (ADS)

Murdoch, Heather A.; Limmer, Krista R.; Labukas, Joseph P.

2017-04-01

Ionic liquids have many advantages over traditional aqueous electrosynthesis for fabrication of functional nanoarchitectures, including enabling the integration of nanoparticles into traditional coatings, superhydrophobicity, nanofoams, and other hierarchical structures. Shape and size control through ionic liquid selection and processing conditions can synthesize nanoparticles and nanoarchitectures without the use of capping agents, surfactants, or templates that are often deleterious to the functionality of the resultant system. Here we give a brief overview of some recent and interesting applications of ionic liquids to the synthesis of nanoparticles and nanoarchitectures.

Synthesis of flower-like Boehmite (γ-AlOOH) via a one-step ionic liquid-assisted hydrothermal route

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tang, Zhe, E-mail: tangzhe1983@163.com; Liang, Jilei, E-mail: liangjilei_httplan@126.com; Li, Xuehui, E-mail: lxhhmx@163.com

A simple and novel synthesis process, one-step ionic liquid-assisted hydrothermal synthesis route, has been developed in the work to synthesize Bohemithe (γ-AlOOH) with flower-like structure. The samples were characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR) and Scanning Electron Microscope (SEM). Ionic liquid [Omim]{sup +}Cl{sup −}, as a template, plays an important role in the morphology and pore structure of the products due to its strong interactions with reaction particles. With the increase in the dosage of ionic liquid [Omim]{sup +}Cl{sup −}, the morphology of the γ-AlOOH was changed from initial bundles of nanosheets (without ionic liquid) intomore » final well-developed monodispersed 3D flower-like architectures ([Omim]{sup +}Cl{sup −}=72 mmol). The pore structure was also altered gradually from initial disordered slit-like pore into final relatively ordered ink-bottle pore. Furthermore, the proposed formation mechanism and other influencing factors such as reaction temperature and urea on formation and morphology of the γ-AlOOH have also been investigated. - Graphical abstract: The flower-like γ-AlOOH architectures composed by nanosheets with narrow size distribution (1.6–2.2 μm) and uniform pore size (6.92 nm) have been synthesized via a one-step ionic liquid-assisted hydrothermal route. - Highlights: • The γ-AlOOH microflowers were synthesized via an ionic liquid-assisted hydrothermal route. • Ionic liquid plays an important role on the morphology and porous structure of the products. • Ionic liquid can be easily removed from the products and reused in recycling experiments. • A “aggregation–recrystallization–Ostwald Ripening“formation mechanism may occur.« less

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

PubMed Central

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

2015-01-01

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

Lithium-Air and ionic Liquids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kellar, Michael

2015-09-01

The final portion of this project was accomplished at Sandia National Labs, Livermore, with the overall goal being to optimize lithium-air cells with an ionic liquid electrolyte. Both of these are potential future routes for lithium-ion technology. Lithiumair presents the advantage of higher gravimetric energy density, and ionic liquids present the advantage of greater hydrophobicity and much lower volatility, along with a larger window of electrochemical stability. Ionic liquids however have several drawbacks for the battery industry. Currently they are not as cost effective as many organic solvents. Additionally, because of the added viscosity of ionic interactions compared to themore » typical dipole interactions of a solvent, the ionic conductivity is lower than for common organic solvents.« less

Tandem dissolution of UO 3 in amide-based acidic ionic liquid and in situ electrodeposition of UO 2 with regeneration of the ionic liquid: a closed cycle

DOE PAGES

Wanigasekara, Eranda; Freiderich, John W.; Sun, Xiao-Guang; ...

2016-05-19

A closed cycle is demonstrated for the tandem dissolution and electroreduction of UO 3 to UO 2 with regeneration of the acidic ionic liquid. The dissolution is achieved by use of the acidic ionic liquid N,N-dimethylacetimidium bis(trifluoromethanesulfonimide) in 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonimide) serving as the diluent. Bulk electrolysis performed at 1.0 V vs. Ag reference yields a dark brown-black uranium deposit (UO 2) on the cathode. Anodic oxidation of water in the presence of dimethylacetamide regenerates the acidic ionic liquid. We have demonstrated the individual steps in the cycle together with a sequential dissolution, electroreduction, and regeneration cycle.

Tandem dissolution of UO 3 in amide-based acidic ionic liquid and in situ electrodeposition of UO 2 with regeneration of the ionic liquid: a closed cycle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wanigasekara, Eranda; Freiderich, John W.; Sun, Xiao-Guang

A closed cycle is demonstrated for the tandem dissolution and electroreduction of UO 3 to UO 2 with regeneration of the acidic ionic liquid. The dissolution is achieved by use of the acidic ionic liquid N,N-dimethylacetimidium bis(trifluoromethanesulfonimide) in 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonimide) serving as the diluent. Bulk electrolysis performed at 1.0 V vs. Ag reference yields a dark brown-black uranium deposit (UO 2) on the cathode. Anodic oxidation of water in the presence of dimethylacetamide regenerates the acidic ionic liquid. We have demonstrated the individual steps in the cycle together with a sequential dissolution, electroreduction, and regeneration cycle.

A molecular dynamics study of lithium-containing aprotic heterocyclic ionic liquid electrolytes

NASA Astrophysics Data System (ADS)

Lourenço, Tuanan C.; Zhang, Yong; Costa, Luciano T.; Maginn, Edward J.

2018-05-01

Classical molecular dynamics simulations were performed on twelve different ionic liquids containing aprotic heterocyclic anions doped with Li+. These ionic liquids have been shown to be promising electrolytes for lithium ion batteries. Self-diffusivities, lithium transference numbers, densities, and free volumes were computed as a function of lithium concentration. The dynamics and free volume decreased with increasing lithium concentration, and the trends were rationalized by examining the changes to the liquid structure. Of those examined in the present work, it was found that (methyloxymethyl)triethylphosphonium triazolide ionic liquids have the overall best performance.

Facile EG/ionic liquid interfacial synthesis of uniform RE(3+) doped NaYF(4) nanocubes.

PubMed

Zhang, Chao; Chen, Ji

2010-01-28

Uniform multicolor upconversion luminescent RE(3+) doped NaYF(4) nanocubes are fabricated through a facile ethylene glycol (EG)/ionic liquid interfacial synthesis route at 80 degrees C, with the ionic liquids acting as both reagents and templates.

Effect of ionic liquid treatment on the ultrastructural and topochemical features of compression wood in Japanese cedar (Cryptomeria japonica).

PubMed

Kanbayashi, Toru; Miyafuji, Hisashi

2016-07-18

The morphological and topochemical changes in wood tissues in compression wood of Japanese cedar (Cryptomeria japonica) upon treated with two types of ionic liquids, 1-ethyl-3-methylimidazolium chloride ([C2mim][Cl]) and 1-ethylpyridinium bromide ([EtPy][Br]) were investigated. Compression wood tracheids were swollen by both ionic liquids but their swelling behaviors were different in the types of ionic liquids used. Under the polarized light, we confirmed that crystalline cellulose in compression wood is amorphized by [C2mim][Cl] treatment whereas it changes slightly by [EtPy][Br] treatment. Raman microscopic analyses revealed that [C2mim][Cl] can preferentially liquefy polysaccharides in compression wood whereas [EtPy][Br] liquefy lignin. In addition, the interaction of compression wood with ionic liquids is different for the morphological regions. These results will assist in the use of ionic liquid treatment of woody biomass to produce valuable chemicals, bio-fuels, bio-based composites and other products.

Effect of ionic liquid treatment on the ultrastructural and topochemical features of compression wood in Japanese cedar (Cryptomeria japonica)

PubMed Central

Kanbayashi, Toru; Miyafuji, Hisashi

2016-01-01

The morphological and topochemical changes in wood tissues in compression wood of Japanese cedar (Cryptomeria japonica) upon treated with two types of ionic liquids, 1-ethyl-3-methylimidazolium chloride ([C2mim][Cl]) and 1-ethylpyridinium bromide ([EtPy][Br]) were investigated. Compression wood tracheids were swollen by both ionic liquids but their swelling behaviors were different in the types of ionic liquids used. Under the polarized light, we confirmed that crystalline cellulose in compression wood is amorphized by [C2mim][Cl] treatment whereas it changes slightly by [EtPy][Br] treatment. Raman microscopic analyses revealed that [C2mim][Cl] can preferentially liquefy polysaccharides in compression wood whereas [EtPy][Br] liquefy lignin. In addition, the interaction of compression wood with ionic liquids is different for the morphological regions. These results will assist in the use of ionic liquid treatment of woody biomass to produce valuable chemicals, bio-fuels, bio-based composites and other products. PMID:27426470

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

PubMed

García, Gregorio; Atilhan, Mert; Aparicio, Santiago

2015-09-17

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

Ionic liquid stationary phases for gas chromatography.

PubMed

Poole, Colin F; Poole, Salwa K

2011-04-01

This article provides a summary of the development of ionic liquids as stationary phases for gas chromatography beginning with early work on packed columns that established details of the retention mechanism and established working methods to characterize selectivity differences compared with molecular stationary phases through the modern development of multi-centered cation and cross-linked ionic liquids for high-temperature applications in capillary gas chromatography. Since there are many reviews on ionic liquids dealing with all aspects of their chemical and physical properties, the emphasis in this article is placed on the role of gas chromatography played in the design of ionic liquids of low melting point, high thermal stability, high viscosity, and variable selectivity for separations. Ionic liquids provide unprecedented opportunities for extending the selectivity range and temperature-operating range of columns for gas chromatography, an area of separation science that has otherwise been almost stagnant for over a decade. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electrodeposition of Si from an Ionic Liquid Bath at Room Temperature in the Presence of Water.

PubMed

Shah, Nisarg K; Pati, Ranjan Kumar; Ray, Abhijit; Mukhopadhyay, Indrajit

2017-02-21

The electrochemical deposition of Si has been carried out in an ionic liquid medium in the presence of water in a limited dry nitrogen environment on highly oriented pyrolytic graphite (HOPG) at room temperature. It has been found that the presence of water in ionic liquids does not affect the available effective potential window to a large extent. Silicon has been successfully deposited electrochemically in the overpotential regime in two different ionic liquids, namely, BMImTf 2 N and BMImPF 6 , in the presence of water. Although a Si thin film has been obtained from BMImTf 2 N; only distinguished Si crystals protected in ionic liquid droplets have been observed from BMImPF 6 . The most important observation of the present investigation is that the Si precursor, SiCl 4 , instead of undergoing hydrolysis, even in the presence of water, coexisted with ionic liquids, and elemental Si has been successfully electrodeposited.

Structure and dynamics of mica-confined films of [C10C1Pyrr][NTf2] ionic liquid

NASA Astrophysics Data System (ADS)

Freitas, Adilson Alves de; Shimizu, Karina; Smith, Alexander M.; Perkin, Susan; Canongia Lopes, José Nuno

2018-05-01

The structure of the ionic liquid 1-decyl-1-methylpyrrolidinium bis[(trifluoromethane)sulfonyl]imide, [C10C1Pyrr][NTf2], has been probed using Molecular Dynamics (MD) simulations. The simulations endeavour to model the behaviour of the ionic liquid in bulk isotropic conditions and also at interfaces and in confinement. The MD results have been confronted and validated with scattering and surface force experiments reported in the literature. The calculated structure factors, distribution functions, and density profiles were able to provide molecular and mechanistic insights into the properties of these long chain ionic liquids under different conditions, in particular those that lead to the formation of multi-layered ionic liquid films in confinement. Other properties inaccessible to experiment such as in-plane structures and relaxation rates within the films have also been analysed. Overall the work contributes structural and dynamic information relevant to many applications of ionic liquids with long alkyl chains, ranging from nanoparticle synthesis to lubrication.

Synthesis of 5-(hydroxymethyl)furfural in ionic liquids: paving the way to renewable chemicals.

PubMed

Ståhlberg, Tim; Fu, Wenjing; Woodley, John M; Riisager, Anders

2011-04-18

The synthesis of 5-(hydroxymethyl)furfural (HMF) in ionic liquids is a field that has grown rapidly in recent years. Unique dissolving properties for crude biomass in combination with a high selectivity for HMF formation from hexose sugars make ionic liquids attractive reaction media for the production of chemicals from renewable resources. A wide range of new catalytic systems that are unique for the transformation of glucose and fructose to HMF in ionic liquids has been found. However, literature examples of scale-up and process development are still scarce, and future research needs to complement the new chemistry with studies on larger scales in order to find economically and environmentally feasible processes for HMF production in ionic liquids. This Minireview surveys important progress made in catalyst development for the synthesis of HMF in ionic liquids, and proposes future research directions in process technology. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mesoporous and biocompatible surface active silica aerogel synthesis using choline formate ionic liquid.

PubMed

Meera, Kamal Mohamed Seeni; Sankar, Rajavelu Murali; Jaisankar, Sellamuthu N; Mandal, Asit Baran

2011-09-01

In this paper, we report the preparation and characterization of mesoporous and biocompatible transparent silica aerogel by the sol-gel polymerization of tetraethyl orthosilicate using ionic liquid. Choline cation based ionic liquid allows the silica framework to form in a non collapsing environment and controls the pore size of the gel. FT-IR spectra reveal the interaction of ionic liquid with surface -OH of the gel. DSC thermogram giving the evidence of confinement of ionic liquid within the silica matrix, which helps to avoid the shrinkage of the gel during the aging process. Nitrogen sorption measurements of gel prepared with ionic liquid exhibit a low surface area of 100.53 m2/g and high average pore size of 3.74 nm. MTT assay proves the biocompatibility and cell viability of the prepared gels. This new nanoporous silica material can be applied to immobilize biological molecules, which may retain their stability over a longer period. Copyright © 2011 Elsevier B.V. All rights reserved.

Heterogeneous dynamics of ionic liquids: A four-point time correlation function approach

NASA Astrophysics Data System (ADS)

Liu, Jiannan; Willcox, Jon A. L.; Kim, Hyung J.

2018-05-01

Many ionic liquids show behavior similar to that of glassy systems, e.g., large and long-lasted deviations from Gaussian dynamics and clustering of "mobile" and "immobile" groups of ions. Herein a time-dependent four-point density correlation function—typically used to characterize glassy systems—is implemented for the ionic liquids, choline acetate, and 1-butyl-3-methylimidazolium acetate. Dynamic correlation beyond the first ionic solvation shell on the time scale of nanoseconds is found in the ionic liquids, revealing the cooperative nature of ion motions. The traditional solvent, acetonitrile, on the other hand, shows a much shorter length-scale that decays after a few picoseconds.

Synthesis of new solid polymer electrolyte and actuator based on PEDOT/NBR/ionic liquid

NASA Astrophysics Data System (ADS)

Cho, M. S.; Seo, H. J.; Nam, J. D.; Choi, H. R.; Koo, J. C.; Lee, Y.

2006-03-01

The conducting polymer actuator was presented. The solid polymer electrolyte based on nitrile rubber (NBR) activated with different ionic liquids was prepared. The three different grades of NBR films were synthesized by emulsion polymerization with different amount of acrylonitrile, 23, 35, and 40 mol. %, respectively. The effect of acrylonitrile content on the ionic conductivity and dielectric constant of solid polymer electrolytes was characterized. A conducting polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), was synthesized on the surface of the NBR layer by using a chemical oxidation polymerization technique, and room temperature ionic liquids (RTIL) based on imidazolium salts, e.g. 1-butyl-3-methyl imidazolium X [where X= BF 4 -, PF 6 -, (CF 3SO II) IIN -], were absorbed into the composite film. The effects of the anion size of the ionic liquids on the displacement of the actuator were examined. The displacement increased with increasing the anion-size of the ionic liquids.

Thermoelectric Generators Based on Ionic Liquids

NASA Astrophysics Data System (ADS)

Laux, Edith; Uhl, Stefanie; Jeandupeux, Laure; López, Pilar Pérez; Sanglard, Pauline; Vanoli, Ennio; Marti, Roger; Keppner, Herbert

2018-03-01

Looking at energy harvesting using body or waste heat for portable electronic or on-board devices, Ionic liquids are interesting candidates as thermoactive materials in thermoelectric generators (TEGs) because of their outstanding properties. Two different kinds of ionic liquid, with alkylammonium and choline as cations, were studied, whereby different anions and redox couples were combined. This study focussed on the intention to find non-hazardous and environmentally friendly ionic liquids for TEGs to be selected among the thousands that can potentially be used. Seebeck coefficients (SEs) as high as - 15 mV/K were measured, in a particular case for an electrode temperature difference of 20 K. The bottleneck of our TEG device is still the abundance of negative SE liquids matching the internal resistance with the existing positive SE-liquids at series connections. In this paper, we show further progress in finding increased negative SE liquids. For current extraction from the TEG, the ionic liquid must be blended with a redox couple, allowing carrier exchange in a cyclic process under a voltage which is incuced by the asymmetry of the generator in terms of hot and cold electrodes. In our study, two types of redox pairs were tested. It was observed that a high SE of an ionic liquid/redox blend is not a sufficient condition for high power output. It appears that more complex effects between the ionic liquid and the electrode determine the magnitude of the final current/power output. The physico-chemical understanding of such a TEG cell is not yet available.

Thermoelectric Generators Based on Ionic Liquids

NASA Astrophysics Data System (ADS)

Laux, Edith; Uhl, Stefanie; Jeandupeux, Laure; López, Pilar Pérez; Sanglard, Pauline; Vanoli, Ennio; Marti, Roger; Keppner, Herbert

2018-06-01

Looking at energy harvesting using body or waste heat for portable electronic or on-board devices, Ionic liquids are interesting candidates as thermoactive materials in thermoelectric generators (TEGs) because of their outstanding properties. Two different kinds of ionic liquid, with alkylammonium and choline as cations, were studied, whereby different anions and redox couples were combined. This study focussed on the intention to find non-hazardous and environmentally friendly ionic liquids for TEGs to be selected among the thousands that can potentially be used. Seebeck coefficients (SEs) as high as - 15 mV/K were measured, in a particular case for an electrode temperature difference of 20 K. The bottleneck of our TEG device is still the abundance of negative SE liquids matching the internal resistance with the existing positive SE-liquids at series connections. In this paper, we show further progress in finding increased negative SE liquids. For current extraction from the TEG, the ionic liquid must be blended with a redox couple, allowing carrier exchange in a cyclic process under a voltage which is incuced by the asymmetry of the generator in terms of hot and cold electrodes. In our study, two types of redox pairs were tested. It was observed that a high SE of an ionic liquid/redox blend is not a sufficient condition for high power output. It appears that more complex effects between the ionic liquid and the electrode determine the magnitude of the final current/power output. The physico-chemical understanding of such a TEG cell is not yet available.

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

NASA Astrophysics Data System (ADS)

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

2012-09-01

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

A Phosphine-mediated Synthesis of 2,3,4,5-tetra-substituted N-hydroxypyrroles from α-oximino Ketones and Dialkyl Acetylenedicarboxylates Under Ionic Liquid Green-media.

PubMed

Shahvelayati, Ashraf S; Ghazvini, Maryam; Yadollahzadeh, Khadijeh; Delbari, Akram S

2018-01-01

The development of multicomponent reactions (MCRs) in the presence of task-specific ionic liquids (ILs), used not only as environmentally benign reaction media, but also as catalysts, is a new approach that meet with the requirements of sustainable chemistry. In recent years, the use of ionic liquids as a green media for organic synthesis has become a chief study area. This is due to their unique properties such as non-volatility, non-flammability, chemical and thermal stability, immiscibility with both organic compounds and water and recyclability. Ionic liquids are used as environmentally friendly solvents instead of hazardous organic solvents. We report the condensation reaction between α-oximinoketone and dialkyl acetylene dicarboxylate in the presence of triphenylphosphine to afford substituted pyrroles under ionic liquid conditions in good yields. Densely functionalized pyrroles was easily prepared from reaction of α-oximinoketones, dialkyl acetylene dicarboxylate in the presence of triphenylphosphine in a quantitative yield under ionic liquid conditions at room temperature. In conclusion, ionic liquids are indicated as a useful and novel reaction medium for the selective synthesis of functionalized pyrroles. This reaction medium can replace the use of hazardous organic solvents. Easy work-up, synthesis of polyfunctional compounds, decreased reaction time, having easily available-recyclable ionic liquids, and good to high yields are advantages of present method. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

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

PubMed

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

2016-07-01

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

Simulation studies of ionic liquids: Orientational correlations and static dielectric properties

NASA Astrophysics Data System (ADS)

Schröder, C.; Rudas, T.; Steinhauser, O.

2006-12-01

The ionic liquids BMIM+I-, BMIM+BF4-, and BMIM+PF6- were simulated by means of the molecular dynamics method over a time period of more than 100ns. Besides the common structural analysis, e.g., radial distribution functions and three dimensional occupancy plots, a more sophisticated orientational analysis was performed. The angular correlation functions g00110(r) and g00101(r) are the first distance dependent coefficients of the pairwise orientational distribution function g(rij,Ω1,Ω2,Ω12). These functions help to interpret the three dimensional plot and reveal interesting insights into the local structure of the analyzed ionic liquids. Furthermore, the collective network of ionic liquids can be characterized by the Kirkwood factor Gκ(r ) [J. Chem. Phys. 7, 911 (1939)]. The short-range behavior (r<10Å) of this factor may be suitable to predict the water miscibility of the ionic liquid. The long-range limit of Gk∞ is below 1 which demonstrates the strongly coupled nature of the ionic liquid networks. In addition, this factor relates the orientational structure and the dielectric properties of the ionic liquids. The static dielectric constant ɛ(ω =0) for the simulated system is 8.9-9.5. Since in ionic liquids the very same molecule contributes to the total dipole moment as well as carries a net charge, a small, but significant contribution of the cross term between the total dipole moment and the electric current to ɛ(ω =0) is observed.

Ionic Liquid as a Solvent and Catalyst for Acylation of Maltodextrin

USDA-ARS?s Scientific Manuscript database

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

Physics of transduction in ionic liquid-swollen Nafion membranes

NASA Astrophysics Data System (ADS)

Bennett, Matthew; Leo, Donald

2006-03-01

Ionic polymer transducers are a class of electroactive polymers that are able to generate large strains (1-5%) in response to low voltage inputs (1-5 V). Additionally, these materials generate electrical charge in response to mechanical strain and are therefore able to operate as soft, distributed sensors. Traditionally, ionic polymer transducers have been limited in their application by their hydration dependence. This work seeks to overcome this limitation by replacing the water with an ionic liquid. Ionic liquids are molten salts that exhibit very high thermal and electrochemical stability while also possessing high ionic conductivity. Results have shown that an ionic liquid-swollen ionic polymer transducer can operate for more than 250,000 cycles in air as compared to about 2,000 cycles for a water-swollen transducer. The current work examines the mechanisms of transduction in ionic liquid-swollen transducers based on Nafion polymer membranes. Specifically, the morphology and relevant ion associations within these membranes are investigated by the use of small-angle X-ray scattering (SAXS), Fourier transform infrared spectroscopy (FTIR), and nuclear magnetic resonance spectroscopy (NMR). These results reveal that the ionic liquid interacts with the membrane in much the same way that water does, and that the counterions of the Nafion polymer are the primary charge carriers. The results of these analyses are compared to the macroscopic transduction behavior in order to develop a model of the charge transport mechanism responsible for electromechanical coupling in these membranes.

Heat Capacity of Room-Temperature Ionic Liquids: A Critical Review

NASA Astrophysics Data System (ADS)

Paulechka, Yauheni U.

2010-09-01

Experimental data on heat capacity of room-temperature ionic liquids in the liquid state were compiled and critically evaluated. The compilation contains data for 102 aprotic ionic liquids from 63 literature references and covers the period of time from 1998 through the end of February 2010. Parameters of correlating equations for temperature dependence of the heat capacities were developed.

Low light CMOS contact imager with an integrated poly-acrylic emission filter for fluorescence detection.

PubMed

Dattner, Yonathan; Yadid-Pecht, Orly

2010-01-01

This study presents the fabrication of a low cost poly-acrylic acid (PAA) based emission filter integrated with a low light CMOS contact imager for fluorescence detection. The process involves the use of PAA as an adhesive for the emission filter. The poly-acrylic solution was chosen due its optical transparent properties, adhesive properties, miscibility with polar protic solvents and most importantly its bio-compatibility with a biological environment. The emission filter, also known as an absorption filter, involves dissolving an absorbing specimen in a polar protic solvent and mixing it with the PAA to uniformly bond the absorbing specimen and harden the filter. The PAA is optically transparent in solid form and therefore does not contribute to the absorbance of light in the visible spectrum. Many combinations of absorbing specimen and polar protic solvents can be derived, yielding different filter characteristics in different parts of the spectrum. We report a specific combination as a first example of implementation of our technology. The filter reported has excitation in the green spectrum and emission in the red spectrum, utilizing the increased quantum efficiency of the photo sensitive sensor array. The thickness of the filter (20 μm) was chosen by calculating the desired SNR using Beer-Lambert's law for liquids, Quantum Yield of the fluorophore and the Quantum Efficiency of the sensor array. The filters promising characteristics make it suitable for low light fluorescence detection. The filter was integrated with a fully functional low noise, low light CMOS contact imager and experimental results using fluorescence polystyrene micro-spheres are presented.

Influence Of Zwitterions on Properties and Morphology of Ionomers: Implications for Electro-Active Applications

DTIC Science & Technology

2010-08-01

membranes in EMIm ES ionic liquid at 10 wt% IL concentration resulted in composites with similar mechanical performance, but 1. REPORT DATE (DD-MM...TERMS zwitterionomer, thermal mechanical property, morphology, ionic liquid , ionic conductivity, transducer Tianyu Wu, Rebecca H. Brown, Andrew J. Duncan...expected entanglement concentration. Swelling of the zwitterionomer membranes in EMIm ES ionic liquid at 10 wt% IL concentration resulted in

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

PubMed

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

2011-03-14

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

Comparison of Dilute Acid and Ionic Liquid Pretreatment of Switchgrass: Biomass Recalcitrance, Delignification and Enzymatic Saccharification

USDA-ARS?s Scientific Manuscript database

The efficiency of two biomass pretreatment technologies, dilute acid hydrolysis and dissolution in an ionic liquid, are compared in terms of delignification, saccharification efficiency and saccharide yields with switchgrass serving as a model bioenergy crop. When subject to ionic liquid pretreatme...

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

USDA-ARS?s Scientific Manuscript database

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...

Ionic liquids comprising heteraromatic anions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schneider, William F.; Brennecke, Joan F.; Maginn, Edward J.

2018-04-24

Some embodiments described herein relate to ionic liquids comprising an anion of a heteraromatic compound such as optionally substituted pyrrolide, optionally substituted pyrazolide, optionally substituted indolide, optionally substituted phospholide, or optionally substituted imidazolide. Methods and devices for gas separation or gas absorption related to these ionic liquids are also described herein.

Method and apparatus for lysing and processing algae

DOEpatents

Chew, Geoffrey; Reich, Alton J.; Dykes, Jr., H. Waite H.; Di Salvo, Roberto

2013-03-05

Methods and apparatus for processing algae are described in which a hydrophilic ionic liquid is used to lyse algae cells at lower temperatures than existing algae processing methods. A salt or salt solution is used as a separation agent and to remove water from the ionic liquid, allowing the ionic liquid to be reused. The used salt may be dried or concentrated and reused. The relatively low lysis temperatures and recycling of the ionic liquid and salt reduce the environmental impact of the algae processing while providing biofuels and other useful products.

Switchable solvents and methods of use thereof

DOEpatents

Jessop, Philip G.; Eckert, Charles A.; Liotta, Charles L.; Heldebrant, David J.

2013-08-20

A solvent that reversibly converts from a nonionic liquid mixture to an ionic liquid upon contact with a selected trigger, e.g., contact with CO.sub.2, is described. In preferred embodiments, the ionic solvent is readily converted back to the nonionic liquid mixture. The nonionic liquid mixture includes an amidine or guanidine or both, and water, alcohol, or a combination thereof. Single component amine solvents that reversibly convert between ionic and non-ionic states are also described. Some embodiments require increased pressure to convert; others convert at 1 atmosphere.

Switchable solvents and methods of use thereof

DOEpatents

Jessop, Philip G [Kingston, CA; Eckert, Charles A [Atlanta, GA; Liotta, Charles L [Atlanta, GA; Heldebrant, David J [Richland, WA

2011-07-19

A solvent that reversibly converts from a nonionic liquid mixture to an ionic liquid upon contact with a selected trigger, e.g., contact with CO.sub.2, is described. In preferred embodiments, the ionic solvent is readily converted back to the nonionic liquid mixture. The nonionic liquid mixture includes an amidine or guanidine or both, and water, alcohol, or a combination thereof. Single component amine solvents that reversibly convert between ionic and non-ionic states are also described. Some embodiments require increased pressure to convert; others convert at 1 atmosphere.

Recent advances of ionic liquids and polymeric ionic liquids in capillary electrophoresis and capillary electrochromatography.

PubMed

Tang, Sheng; Liu, Shujuan; Guo, Yong; Liu, Xia; Jiang, Shengxiang

2014-08-29

Ionic liquids (ILs) and polymeric ionic liquids (PILs) with unique and fascinating properties have drawn considerable interest for their use in separation science, especially in chromatographic techniques. In this article, significant contributions of ILs and PILs in the improvement of capillary electrophoresis and capillary electrochromatography are described, and a specific overview of the most relevant examples of their applications in the last five years is also given. Accordingly, some general conclusions and future perspectives in these areas are discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

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

PubMed

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

2015-05-29

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

Switchable solvents and methods of use thereof

DOEpatents

Jessop, Philip G; Eckert, Charles A; Liotta, Charles L; Heldebrant, David J

2014-04-29

A solvent that reversibly converts from a nonionic liquid mixture to an ionic liquid upon contact with a selected trigger, e.g., contact with CO.sub.2, is described. In preferred embodiments, the ionic solvent is readily converted back to the nonionic liquid mixture. The nonionic liquid mixture includes an amidine or guanidine or both, and water, alcohol, or a combination thereof. Single component amine solvents that reversibly convert between ionic and non-ionic states are also described. Some embodiments require increased pressure to convert; others convert at 1 atmosphere.

Disorder from the Bulk Ionic Liquid in Electric Double Layer Transistors

DOE PAGES

Petach, Trevor A.; Reich, Konstantin V.; Zhang, Xiao; ...

2017-07-28

Ionic liquid gating has a number of advantages over solid-state gating, especially for flexible or transparent devices and for applications requiring high carrier densities. But, the large number of charged ions near the channel inevitably results in Coulomb scattering, which limits the carrier mobility in otherwise clean systems. We develop a model for this Coulomb scattering. We then validate our model experimentally using ionic liquid gating of graphene across varying thicknesses of hexagonal boron nitride, demonstrating that disorder in the bulk ionic liquid often dominates the scattering.

Cobalt-Bridged Ionic Liquid Polymer on a Carbon Nanotube for Enhanced Oxygen Evolution Reaction Activity.

PubMed

Ding, Yuxiao; Klyushin, Alexander; Huang, Xing; Jones, Travis; Teschner, Detre; Girgsdies, Frank; Rodenas, Tania; Schlögl, Robert; Heumann, Saskia

2018-03-19

By taking inspiration from the catalytic properties of single-site catalysts and the enhancement of performance through ionic liquids on metal catalysts, we exploited a scalable way to place single cobalt ions on a carbon-nanotube surface bridged by polymerized ionic liquid. Single dispersed cobalt ions coordinated by ionic liquid are used as heterogeneous catalysts for the oxygen evolution reaction (OER). Performance data reveals high activity and stable operation without chemical instability. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

Industrial uses and applications of ionic liquids

NASA Astrophysics Data System (ADS)

Gutowski, Keith E.

2018-02-01

Ionic liquids are salts that melt at low temperatures (usually defined as less than 100 °C) and have a number of interesting properties that make them useful for industrial applications. Typical ionic liquid properties include high thermal stabilities, negligible vapor pressures, wide liquidus ranges, broad electrochemical windows, and unique solvation properties. Furthermore, the potential combinations of cations and anions provide nearly unlimited chemical tunability. This article will describe the diverse industrial uses of ionic liquids and how their unique properties are leveraged, with examples ranging from chemical processing to consumer packaged goods.

Formation of p-n-p junction with ionic liquid gate in graphene

DOE Office of Scientific and Technical Information (OSTI.GOV)

He, Xin; Tang, Ning, E-mail: ntang@pku.edu.cn, E-mail: geweikun@mail.tsinghua.edu.cn, E-mail: bshen@pku.edu.cn; Duan, Junxi

2014-04-07

Ionic liquid gating is a technique which is much more efficient than solid gating to tune carrier density. To observe the electronic properties of such a highly doped graphene device, a top gate made of ionic liquid has been used. By sweeping both the top and back gate voltage, a p-n-p junction has been created. The mechanism of forming the p-n-p junction has been discussed. Tuning the carrier density by ionic liquid gate can be an efficient method to be used in flexible electronics.

Spectacular Rate Enhancement of the Diels-Alder Reaction at the Ionic Liquid/n-Hexane Interface.

PubMed

Beniwal, Vijay; Manna, Arpan; Kumar, Anil

2016-07-04

The use of the ionic liquid/n-hexane interface as a new class of reaction medium for the Diels-Alder reaction gives large rate enhancements of the order of 10(6) to 10(8) times and high stereoselectivity, as compared to homogeneous media. The rate enhancement is attributed to the H-bonding abilities and polarities of the ionic liquids, whereas the hydrophobicity of ionic liquids was considered to be the factor in controlling stereoselectivity. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Modeling electrokinetics in ionic liquids: General

DOE PAGES

Wang, Chao; Bao, Jie; Pan, Wenxiao; ...

2017-04-01

Using direct numerical simulations, we provide a thorough study regarding the electrokinetics of ionic liquids. In particular, modified Poisson–Nernst–Planck equations are solved to capture the crowding and overscreening effects characteristic of an ionic liquid. For modeling electrokinetic flows in an ionic liquid, the modified Poisson-Nernst-Planck equations are coupled with Navier–Stokes equations to study the coupling of ion transport, hydrodynamics, and electrostatic forces. Specifically, we consider the ion transport between two parallel charged surfaces, charging dynamics in a nanopore, capacitance of electric double-layer capacitors, electroosmotic flow in a nanochannel, electroconvective instability on a plane ion-selective surface, and electroconvective flow on amore » curved ionselective surface. Lastly, we also discuss how crowding and overscreening and their interplay affect the electrokinetic behaviors of ionic liquids in these application problems.« less

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

PubMed

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

2017-04-01

The mechanism of toxicity of chiral ionic liquids with (1R,2S,5R)-(-)-menthol [C n -Am-Men][Cl] (n=10, 11 or 12) in the fungus Candida albicans is reported here. Ionic liquids were more toxic towards Candida strain lacking all identified multidrug resistance efflux pumps. Moreover, the compounds tested inhibited C. albicans filamentation at the concentration at which detached fungal cells also adhered to the plastic surface. Our results showed the high activity of all the tested chiral ionic liquids in the permeabilization of C. albicans' membranes and in the digestion and interruption of the cell wall. The investigated ionic liquids thus have potential as disinfectants because besides their antifungal and antiadhesive action these compounds do not cause hemolysis. Copyright © 2017 Elsevier GmbH. All rights reserved.

Dissolution of cellulose in ionic liquid: A review

NASA Astrophysics Data System (ADS)

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

2017-02-01

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

Ionic liquids as solvents for Čerenkov counting and the effect of a wavelength shifter.

PubMed

Mirenda, M; Rodrigues, D; Ferreyra, C; Arenillas, P; Sarmiento, G P; Krimer, N; Japas, M L

2018-04-01

We study the wavelength shift of the Čerenkov light - generated in the ionic liquid (BMIMCl) - caused by the addition of the highly fluorescent ionic liquid (BMIMHPTS). 18 F and 32 P efficiencies increases up to 124% and 14%, respectively, compared with the values obtained with pure BMIMCl. With this improvement, ionic liquid mixtures become a good alternative - when using the TDCR-Cherenkov technique - to standardize radionuclides having electron emissions energies close to the threshold energy in water (∼ 260keV). As an advantage compared with other solvents, the Ionic liquid mixture can be reused, in the case of short-lived radionuclides, by simply removing all water content in a vacuum oven. Copyright © 2017 Elsevier Ltd. All rights reserved.

Performance of carbon-carbon supercapacitors based on organic, aqueous and ionic liquid electrolytes

NASA Astrophysics Data System (ADS)

Lewandowski, Andrzej; Olejniczak, Angelika; Galinski, Maciej; Stepniak, Izabela

Properties of capacitors working with the same carbon electrodes (activated carbon cloth) and three types of electrolytes: aqueous, organic and ionic liquids were compared. Capacitors filled with ionic liquids worked at a potential difference of 3.5 V, their solutions in AN and PC were charged up to the potential difference of 3 V, classical organic systems to 2.5 V and aqueous to 1 V. Cyclic voltammetry, galvanostatic charging/discharging and impedance spectroscopy were used to characterize these capacitors. The highest specific energy was recorded for the device working with ionic liquids, while the highest power is characteristic for the device filled with aqueous H 2SO 4 electrolyte. Aqueous electrolytes led to energy density an order of magnitude lower in comparison to that characteristic of ionic liquids.

Thioimidazolium Ionic Liquids as Tunable Alkylating Agents.

PubMed

Guterman, Ryan; Miao, Han; Antonietti, Markus

2018-01-19

Alkylating ionic liquids based on the thioimidazolium structure combine the conventional properties of ionic liquids, including low melting point and nonvolatility, with the alkylating function. Alkyl transfer occurs exclusively from the S-alkyl position, thus allowing for easy derivatization of the structure without compromising specificity. We apply this feature to tune the electrophilicty of the cation to profoundly affect the reactivity of these alkylating ionic liquids, with a caffeine-derived compound possessing the highest reactivity. Anion choice was found to affect reaction rates, with iodide anions assisting in the alkylation reaction through a "shuttling" process. The ability to tune the properties of the alkylating agent using the toolbox of ionic liquid chemistry highlights the modular nature of these compounds as a platform for alkylating agent design and integration in to future systems.

Ionic liquids containing symmetric quaternary phosphonium cations and phosphorus-containing anions, and their use as lubricant additives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qu, Jun; Luo, Huimin

An ionic liquid composition having the following generic structural formula: ##STR00001## wherein R 1, R 2, R 3, and R 4 are equivalent and selected from hydrocarbon groups containing at least three carbon atoms, and X - is a phosphorus-containing anion, particularly an organophosphate, organophosphonate, or organophosphinate anion, or a thio-substituted analog thereof containing hydrocarbon groups with at least three carbon atoms. Also described are lubricant compositions comprising the above ionic liquid and a base oil, wherein the ionic liquid is dissolved in the base oil. Further described are methods for applying the ionic liquid or lubricant composition onto amore » mechanical device for which lubrication is beneficial, with resulting improvement in friction reduction, wear rate, and/or corrosion inhibition.« less

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

PubMed

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

2016-01-14

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

Effect of the alkyl chain length on the rotational dynamics of nonpolar and dipolar solutes in a series of N-alkyl-N-methylmorpholinium ionic liquids.

PubMed

Khara, Dinesh Chandra; Kumar, Jaini Praveen; Mondal, Navendu; Samanta, Anunay

2013-05-02

Rotational dynamics of two dipolar solutes, 4-aminophthalimide (AP) and 6-propionyl-2-dimethylaminonaphthalene (PRODAN), and a nonpolar solute, anthracene, have been studied in N-alkyl-N-methylmorpholinium (alkyl = ethyl, butyl, hexyl, and octyl) bis(trifluoromethansulfonyl)imide (Tf2N) ionic liquids as a function of temperature and excitation wavelength to probe the microheterogeneous nature of these ionic liquids, which are recently reported to be more structured than the imidazolium ionic liquids (Khara and Samanta, J. Phys. Chem. B2012, 116, 13430-13438). Analysis of the measured rotational time constants of the solutes in terms of the Stokes-Einstein-Debye (SED) hydrodynamic theory reveals that with increase in the alkyl chain length attached to the cationic component of the ionic liquids, AP shows stick to superstick behavior, PRODAN rotation lies between stick and slip boundary conditions, whereas anthracene exhibits slip to sub slip behavior. The contrasting rotational dynamics of these probe molecules is a reflection of their location in distinct environments of the ionic liquids thus demonstrating the heterogeneity of these ionic liquids. The microheterogeneity of these media, in particular, those with the long alkyl chain, is further evidence from the excitation wavelength dependence study of the rotational diffusion of the dipolar probe molecules.

Surface-active ionic liquids in micellar catalysis: impact of anion selection on reaction rates in nucleophilic substitutions† †Electronic supplementary information (ESI) available: Formulae for calculating aggregation parameters and fitting of kinetic constants and copies of NMR spectra. See DOI: 10.1039/c6cp00493h Click here for additional data file.

PubMed Central

Cognigni, Alice; Gaertner, Peter; Zirbs, Ronald; Peterlik, Herwig; Prochazka, Katharina; Schröder, Christian

2016-01-01

A series of surface-active ionic liquids based on the 1-dodecyl-3-methylimidazolium cation and different anions such as halides and alkylsulfates was synthesized. The aggregation behavior of these ionic liquids in water was characterized by surface tension, conductivity measurements and UV-Vis spectroscopy in order to determine the critical micelle concentration (CMC) and to provide aggregation parameters. The determination of surface activity and aggregation properties of amphiphilic ionic liquids was accompanied by SAXS studies on selected surface-active ionic liquids. The application of these surface-active ionic liquids with different anions was tested in nucleophilic substitution reactions for the degradation of organophosphorus compounds. Kinetic studies via UV-Vis spectrophotometry showed a strong acceleration of the reaction in the micellar system compared to pure water. In addition, an influence of the anion was observed, resulting in a correlation between the anion binding to the micelle and the reaction rate constants, indicating that the careful choice of the surface-active ionic liquid can considerably affect the outcome of reactions. PMID:27121134

Thermoresponsive light scattering device utilizing surface behavior effects between polyimide and an ionic liquid-water mixture exhibiting lower critical solution temperature (LCST)-type phase separation

NASA Astrophysics Data System (ADS)

Goda, Kazuya; Takatoh, Kohki; Funasako, Yusuke; Inokuchi, Makoto

2018-06-01

We proposed a thermoresponsive light scattering device that utilizes the surface behavior between polyimide and an ionic liquid-water mixture exhibiting lower critical solution temperature (LCST)-type phase separation. The LCST behavior for an ionic liquid device utilizing the polyimide with and without alkyl side chains was investigated. In the here-reported ionic liquid device that utilized the polyimide with alkyl side chains, [nBu4P][CF3COO] droplets were generated by phase separation—they were predominantly formed at the alkyl surface by a surface pinning effect. A stable transmittance in the opaque state could be obtained with this device. In contrast, an ionic liquid device using polyimide without alkyl side chains deteriorated transmittance in the opaque state because there was no surface pinning effect. Additionally, the viewing angle, contrast ratio, and heat cycle testing of this ionic liquid device with polyimide with alkyl side chains were also investigated. The results indicated that no parallax was obtained and that the ionic liquid device has a stable transmittance (verified by heat cycle testing). This unique device is expected to find use in the smart window applications that are activated by temperature changes.

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

PubMed

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

2015-03-15

A new extraction medium was proposed for liquid-liquid extraction of the histamine H2 receptor antagonists ranitidine (RNT) and nizatidine (NZT). The ionic liquids with low vapor pressure and favorable solvating properties for a range of compounds such as 1-butyl-3-methylimidazolium hexafluorophosphate [C4mim][PF6] and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [C4mim][Tf2N] were tested for isolation of analytes. The extraction parameters of RNT and NZT, namely, amount of ionic liquid, pH of sample solution, shaking and centrifugation time were optimized. The isolation processes were performed with 1 mL of the ionic liquids. The extracted samples (pH values near 4) were shaken at 1750 rpm. The influence of interfering substances on the efficiency of extraction process was also studied. Methods for the histamine H2 receptor antagonists (ranitidine and nizatidine) determination after their separation using imidazolium ionic liquids by high performance liquid chromatography (HPLC) combined with UV spectrophotometry were developed. The application of ionic liquids in extraction step allows for selective isolation of analytes from aqueous matrices and their preconcentration. The above methods were applied to the determination of RNT and NZT in environmental samples (river water and wastewater after treatment). Copyright © 2014 Elsevier B.V. All rights reserved.

Preparation and evaluation of surface-bonded tricationic ionic liquid silica as stationary phases for high-performance liquid chromatography.

PubMed

Qiao, Lizhen; Shi, Xianzhe; Lu, Xin; Xu, Guowang

2015-05-29

Two tricationic ionic liquids were prepared and then bonded onto the surface of supporting silica materials through "thiol-ene" click chemistry as new stationary phases for high-performance liquid chromatography. The obtained columns of tricationic ionic liquids were evaluated respectively in the reversed-phase liquid chromatography (RPLC) mode and hydrophilic interaction liquid chromatography (HILIC) mode, and possess ideal column efficiency of 80,000 plates/m in the RPLC mode with naphthalene as the test solute. The tricationic ionic liquid stationary phases exhibit good hydrophobic and shape selectivity to hydrophobic compounds, and RPLC retention behavior with multiple interactions. In the HILIC mode, the retention and selectivity were evaluated through the efficient separation of nucleosides and bases as well as flavonoids, and the typical HILIC retention behavior was demonstrated by investigating retention changes of hydrophilic solutes with water volume fraction in mobile phase. The results show that the tricationic ionic liquid columns possess great prospect for applications in analysis of hydrophobic and hydrophilic samples. Copyright © 2015 Elsevier B.V. All rights reserved.

Long-range electrostatic screening in ionic liquids

PubMed Central

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

2015-01-01

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

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dhungana, Kamal B.; Faria, Luiz F. O.; Wu, Boning

2016-07-14

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

Self-Regulative Nanogelator Solid Electrolyte: A New Option to Improve the Safety of Lithium Battery.

PubMed

Wu, Feng; Chen, Nan; Chen, Renjie; Zhu, Qizhen; Tan, Guoqiang; Li, Li

2016-01-01

The lack of suitable nonflammable electrolytes has delayed battery application in electric vehicles. A new approach to improve the safety performance for lithium battery is proposed here. This technology is based on a nanogelator-based solid electrolyte made of porous oxides and an ionic liquid. The electrolyte is fabricated using an in situ method and the porous oxides serve as a nonflammable "nanogelator" that spontaneously immobilizes the ionic liquid. The electrolyte exhibits a high liquid-like apparent ionic conductivity of 2.93 × 10 -3 S cm -1 at room temperature. The results show that the nanogelator, which possess self-regulating ability, is able to immobilize imidazolium-, pyrrolidinium-, or piperidinium-based ionic liquids, simply by adjusting the ion transport channels. Our prototype batteries made of Ti-nanogeltor solid electrolyte outperform conventional lithium batteries made using ionic liquid and commercial organic liquid electrolytes.

Surface and Electrochemical Properties of Polymer Brush-Based Redox Poly(Ionic Liquid).

PubMed

Bui-Thi-Tuyet, Van; Trippé-Allard, Gaëlle; Ghilane, Jalal; Randriamahazaka, Hyacinthe

2016-10-26

Redox-active poly(ionic liquid) poly(3-(2-methacryloyloxy ethyl)-1-(N-(ferrocenylmethyl) imidazolium bis(trifluoromethylsulfonyl)imide deposited onto electrode surfaces has been prepared using surface-initiated atom transfer radical polymerization SI-ATRP. The process starts by electrochemical immobilization of initiator layer, and then methacrylate monomer carrying ferrocene and imidazolium units is polymerized in ionic liquid media via SI-ATRP process. The surfaces analyses of the polymer exhibit a well-defined polymer brushlike structure and confirm the presence of ferrocene and ionic moieties within the film. Furthermore, the electrochemical investigations of poly(redox-active ionic liquid) in different media demonstrate that the electron transfer is not restricted by the rate of counterion migration into/out of the polymer. The attractive electrochemical performance of these materials is further demonstrated by performing electrochemical measurement, of poly(ferrocene ionic liquid), in solvent-free electrolyte. The facile synthesis of such highly ordered electroactive materials based ionic liquid could be useful for the fabrication of nanostructured electrode suitable for performing electrochemistry in solvent free electrolyte. We also demonstrate possible applications of the poly(FcIL) as electrochemically reversible surface wettability system and as electrochemical sensor for the catalytic activity toward the oxidation of tyrosine.

Molecular modeling of field-driven ion emission from ionic liquids

NASA Astrophysics Data System (ADS)

Zhang, Fei; He, Yadong; Qiao, Rui

2017-11-01

Traditionally, operating electrosprays in the purely ionic mode is challenging, but recent experiments confirmed that such operation can be achieved using room-temperature ionic liquids as working electrolytes. Such electrosprays have shown promise in applications including chemical analysis, nanomanufacturing, and space propulsion. The mechanistic and quantitative understanding of such electrosprays at the molecular level, however, remain limited at present. In this work, we simulated ion emission from EMIM-PF6 ionic liquid films using the molecular dynamics method. We show that, when the surface electric field is smaller than 1.5V/nm, the ion emission current predicted using coarse-grained ionic liquid model observes the classical scaling law by J. V. Iribarne and B. A. Thomson, i.e., ln(Je/ σ) En1/2. These simulations, however, cannot capture the co-emission of cations and anions from ionic liquid surface observed in some experiments. Such co-emission was successfully captured when united-atom models were adopted for the ionic liquids. By examining the co-emission events with picosecond, sub-angstrom resolution, we clarified the origins of the co-emission phenomenon and delineate the molecular events leading to ion emission.

25th anniversary article: "Cooking carbon with salt": carbon materials and carbonaceous frameworks from ionic liquids and poly(ionic liquid)s.

PubMed

Fellinger, Tim-Patrick; Thomas, Arne; Yuan, Jiayin; Antonietti, Markus

2013-11-06

This review surveys recent work on the use of ionic liquids (ILs) and polymerized ionic liquids (PILs) as precursors to synthesize functional carbon materials. As solvents or educts with negligible vapour pressure, these systems enable simple processing, composition, and structural control of the resulting carbons under rather simple and green synthesis conditions. Recent applications of the resulting nanocarbons across a multitude of fields, such as fuel cells, energy storage in batteries and supercapacitors, catalysis, separation, and sorption materials are highlighted. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Elucidating the correlation between morphology and ion dynamics in polymerized ionic liquids.

NASA Astrophysics Data System (ADS)

Heres, Maximilian; Cosby, Tyler; Iacob, Ciprian; Runt, James; Benson, Roberto; Liu, Hongjun; Paddison, Stephen; Sangoro, Joshua

Charge transport and dynamics are investigated for a series of poly-ammonium and poly-imidazolium-based polymerized ionic liquids (polyIL) with a common bis(trifluoromethylsulfonyl)imide anion using broadband dielectric spectroscopy and temperature modulated differential scanning calorimetry. A significant enhancement of the Tg independent ionic conductivity is observed for ammonium based polyIL with shorter pendant groups, in comparison to imidazolium based systems. These results emphasize the importance of polymer backbone spacing as well as counter-ion size on ionic conductivity in polymerized ionic liquids. NSF DMR 1508394.

An adaptive self-healing ionic liquid nanocomposite membrane for olefin-paraffin separations.

PubMed

Pitsch, Fee; Krull, Florian F; Agel, Friederike; Schulz, Peter; Wasserscheid, Peter; Melin, Thomas; Wessling, Matthias

2012-08-16

An adaptive self-healing ionic liquid nanocomposite membrane comprising a multi-layer support structure hosting the ionic salt [Ag](+) [Tf(2) N](-) is used for the separation of the olefin propylene and the paraffin propane. The ionic salt renders liquid like upon complexation with propylene, resulting in facilitated transport of propylene over propane at benchmark-setting selectivity and permeance levels. The contacting with acetylene causes the ionic salt to liquefy without showing evidence of forming explosive silver acetylide. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ion Transport via Structural Relaxations in Polymerized Ionic Liquids

NASA Astrophysics Data System (ADS)

Ganesan, Venkat; Mogurampelly, Santosh

We study the mechanisms underlying ion transport in poly(1-butyl-3-vinylimidazolium-hexafluorophosphate) polymer electrolytes. We consider polymer electrolytes of varying polymerized ionic liquid to ionic liquid (polyIL:IL) ratios and use atomistic molecular dynamics (MD) simulations to probe the dynamical and structural characteristics of the electrolyte. Our results reveal that anion diffusion along polymer backbone occurs primarily viathe formation and breaking of ion-pairs involving threepolymerized cationic monomers of twodifferent polymer chains. Moreover, we observe that the ionic diffusivities exhibit a direct correlation with the structural relaxation times of the ion-pairs and hydrogen bonds (H-bonds). These results provide new insights into the mechanisms underlying ion transport in polymerized ionic liquid electrolytes.

Determination of Physical Properties of Ionic Liquids Using Molecular Simulations

DTIC Science & Technology

2010-08-20

That is, most groups rely on relatively short (100-500 ps) simulations and evaluate the viscosity via conventional Green - Kubo integration . In this...and can contribute to higher than expected viscosities . The liquid structure of the energetic ionic liquid 2-hydroxyethylhydrizinium nitrate was...claimed previously that neglect of polarizability leads to inaccuracies in the computed transport properties of ionic liquids such as viscosities

Liquid-liquid extraction of actinides, lanthanides, and fission products by use of ionic liquids: from discovery to understanding.

PubMed

Billard, Isabelle; Ouadi, Ali; Gaillard, Clotilde

2011-06-01

Liquid-liquid extraction of actinides and lanthanides by use of ionic liquids is reviewed, considering, first, phenomenological aspects, then looking more deeply at the various mechanisms. Future trends in this developing field are presented.

Impurity effects on ionic-liquid-based supercapacitors

NASA Astrophysics Data System (ADS)

Liu, Kun; Lian, Cheng; Henderson, Douglas; Wu, Jianzhong

2017-02-01

Small amounts of an impurity may affect the key properties of an ionic liquid and such effects can be dramatically amplified when the electrolyte is under confinement. Here the classical density functional theory is employed to investigate the impurity effects on the microscopic structure and the performance of ionic-liquid-based electrical double-layer capacitors, also known as supercapacitors. Using a primitive model for ionic species, we study the effects of an impurity on the double layer structure and the integral capacitance of a room temperature ionic liquid in model electrode pores and find that an impurity strongly binding to the surface of a porous electrode can significantly alter the electric double layer structure and dampen the oscillatory dependence of the capacitance with the pore size of the electrode. Meanwhile, a strong affinity of the impurity with the ionic species affects the dependence of the integral capacitance on the pore size. Up to 30% increase in the integral capacitance can be achieved even at a very low impurity bulk concentration. By comparing with an ionic liquid mixture containing modified ionic species, we find that the cooperative effect of the bounded impurities is mainly responsible for the significant enhancement of the supercapacitor performance.

Electronic functions of solid-to-liquid interfaces of organic semiconductor crystals and ionic liquid

NASA Astrophysics Data System (ADS)

Takeya, J.

2008-10-01

The environment of surface electrons at 'solid-to-liquid' interfaces is somewhat extreme, subjected to intense local electric fields or harsh chemical pressures that high-density ionic charge or polarization of mobile molecules create. In this proceedings, we argue functions of electronic carriers generated at the surface of organic semiconductor crystals in response to the local electric fields in the very vicinity of the interface to ionic liquid. The ionic liquids (ILs), or room temperature molten salts, are gaining considerable interest in the recent decade at the prospect of nonvolatile 'green solvents', with the development of chemically stable and nontoxic compounds. Moreover, such materials are also applied to electrolytes for lithium ion batteries and electric double-layer (EDL) capacitors. Our present solid-to-liquid interfaces of rubrene single crystals and ionic liquids work as fast-switching organic field-effect transistors (OFETs) with the highest transconductance, i.e. the most efficient response of the output current to the input voltage, among the OFETs ever built.

Influence of Nanosegregation on the Surface Tension of Fluorinated Ionic Liquids

PubMed Central

Luís, Andreia; Shimizu, Karina; Araújo, João M. M.; Carvalho, Pedro J.; Lopes-da-Silva, José A.; Canongia Lopes, José N.; Rebelo, Luís Paulo N.; Coutinho, João A. P.; Freire, Mara G.; Pereiro, Ana B.

2017-01-01

We have investigated, both theoretically and experimentally, the balance between the presence of alkyl and perfluoroalkyl side chains on the surface organization and surface tension of fluorinated ionic liquids (FILs). A series of ILs composed of 1-alkyl-3-methylimidazolium cations ([CnC1im] with n = 2, 4, 6, 8, 10 or 12) combined with the perfluorobutanesulfonate anion was used. The surface tensions of the investigated liquid salts are considerably lower than those reported for non-fluorinated ionic liquids. The most surprising and striking feature was the identification, for the first time, of a minimum at n = 8 in the surface tension versus the length of the IL cation alkyl side chain. Supported by molecular dynamic simulations it was found that this trend is a result of the competition between the two nonpolar domains (perfluorinated and aliphatic) on pointing towards the gas-liquid interface, a phenomenon which occurs in ionic liquids with perfluorinated anions. Furthermore, these ionic liquids present the lowest surface entropy reported to date. PMID:27218210

Microwave-assisted liquid-liquid microextraction based on solidification of ionic liquid for the determination of sulfonamides in environmental water samples.

PubMed

Song, Ying; Wu, Lijie; Lu, Chunmei; Li, Na; Hu, Mingzhu; Wang, Ziming

2014-12-01

An easy, quick, and green method, microwave-assisted liquid-liquid microextraction based on solidification of ionic liquid, was first developed and applied to the extraction of sulfonamides in environmental water samples. 1-Ethy-3-methylimidazolium hexafluorophosphate, which is a solid-state ionic liquid at room temperature, was used as extraction solvent in the present method. After microwave irradiation for 90 s, the solid-state ionic liquid was melted into liquid phase and used to finish the extraction of the analytes. The ionic liquid and sample matrix can be separated by freezing and centrifuging. Several experimental parameters, including amount of extraction solvent, microwave power and irradiation time, pH of sample solution, and ionic strength, were investigated and optimized. Under the optimum experimental conditions, good linearity was observed in the range of 2.00-400.00 μg/L with the correlation coefficients ranging from 0.9995 to 0.9999. The limits of detection for sulfathiazole, sulfachlorpyridazine, sulfamethoxazole, and sulfaphenazole were 0.39, 0.33, 0.62, and 0.85 μg/L, respectively. When the present method was applied to the analysis of environmental water samples, the recoveries of the analytes ranged from 75.09 to 115.78% and relative standard deviations were lower than 11.89%. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ionic liquids behave as dilute electrolyte solutions

PubMed Central

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

2013-01-01

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

Lidocaine self-sacrificially improves the skin permeation of the acidic and poorly water-soluble drug etodolac via its transformation into an ionic liquid.

PubMed

Miwa, Yasushi; Hamamoto, Hidetoshi; Ishida, Tatsuhiro

2016-05-01

Poor transdermal penetration of active pharmaceutical ingredients (APIs) impairs both bioavailability and therapeutic benefits and is a major challenge in the development of transdermal drug delivery systems. Here, we transformed a poorly water-soluble drug, etodolac, into an ionic liquid in order to improve its hydrophobicity, hydrophilicity and skin permeability. The ionic liquid was prepared by mixing etodolac with lidocaine (1:1, mol/mol). Both the free drug and the transformed ionic liquid were characterized by differential scanning colorimetry (DSC), infrared spectroscopy (IR), and saturation concentration measurements. In addition, in vitro skin-permeation testing was carried out via an ionic liquid-containing patch (Etoreat patch). The lidocaine and etodolac in ionic liquid form led to a relatively lower melting point than either lidocaine or etodolac alone, and this improved the lipophilicity/hydrophilicity of etodolac. In vitro skin-permeation testing demonstrated that the Etoreat patch significantly increased the skin permeation of etodolac (9.3-fold) compared with an etodolac alone patch, although an Etoreat patch did not increase the skin permeation of lidocaine, which was consistent with the results when using a lidocaine alone patch. Lidocaine appeared to self-sacrificially improve the skin permeation of etodolac via its transformation into an ionic liquid. The data suggest that ionic liquids composed of approved drugs may substantially expand the formulation preparation method to meet the challenges of drugs which are characterized by poor rates of transdermal absorption. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Chemical and Electrochemical Studies in Ionic Liquids

DTIC Science & Technology

1990-01-12

Electrochemistry and Witchcraft ", Gordon Research Conference on Electrochemistry", Santa Barbara, CA, January, 1985. OR. A. Osteryoung, ’An Introduction to...Temperature Chloroaluminate Ionic Liquids: Chemistry, Electrochemistry and Witchcraft ", Chemistry Department Colloquium, University of Alabama...Tuscaloosa, Alabama, December 1, 1988. OR. A. Osteryoung, "Ambient Temperature Chloroaluminate Ionic Liquids: Chemistry, Electrochemistry and Witchcraft

Ionic Liquids and Green Chemistry: A Lab Experiment

ERIC Educational Resources Information Center

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

2010-01-01

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…

Fine tuning the ionic liquid-vacuum outer atomic surface using ion mixtures.

PubMed

Villar-Garcia, Ignacio J; Fearn, Sarah; Ismail, Nur L; McIntosh, Alastair J S; Lovelock, Kevin R J

2015-03-28

Ionic liquid-vacuum outer atomic surfaces can be created that are remarkably different from the bulk composition. In this communication we demonstrate, using low-energy ion scattering (LEIS), that for ionic liquid mixtures the outer atomic surface shows significantly more atoms from anions with weaker cation-anion interactions (and vice versa).

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

DOEpatents

Luebke, David; Nulwala, Hunald; Tang, Chau

2014-12-09

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

The Hildebrand solubility parameters of ionic liquids-part 2.

PubMed

Marciniak, Andrzej

2011-01-01

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

Synthesis and polymerization of vinyl triazolium ionic liquids

DOEpatents

Luebke, David; Nulwala, Hunaid; Matyjaszewski, Krzysztof; Adzima, Brian

2018-05-15

Herein, we describe polymerized ionic liquids, demonstrate the synthesis of polymerized ionic liquids, and demonstrate the polymerization of triazolium monomers. One embodiment shows the polymeriazation of the triazolium monomers with bis(trifluoromethanesulfonyl)imide anions. In another embodiment we show the feasibility of copolymerizing with commodity monomers such as styrene using free radical polymerization techniques.

Benzyl-Functionalized Room Temperature Ionic Liquids for CO2/N2 Separation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mahurin, Shannon Mark; Dai, Thomas N; Yeary, Joshua S

2011-01-01

In this work, three classes of room temperature ionic liquids (RTILs), including imidazolium, pyridinium, and pyrrolidinium ionic liquids with a benzyl group appended to the cation, were synthesized and tested for their performance in separating CO{sub 2} and N{sub 2}. All RTILs contained the bis(trifluoromethylsulfonyl)imide anion, permitting us to distinguish the impact of the benzyl moiety attached to the cation on gas separation performance. In general, the attachment of the benzyl group increased the viscosity of the ionic liquid compared with the unfunctionalized analogs and decreased the CO{sub 2} permeability. However, all of the benzyl-modified ionic liquids exhibited enhanced CO{submore » 2}/N{sub 2} selectivities compared with alkyl-based ionic liquids, with values ranging from 22.0 to 33.1. In addition, CO{sub 2} solubilities in the form of Henry's constants were also measured and compared with unfunctionalized analogs. Results of the membrane performance tests and CO{sub 2} solubility measurements demonstrate that the benzyl-functionalized RTILs have significant potential for use in the separation of carbon dioxide from combustion products.« less

Highly stable noble-metal nanoparticles in tetraalkylphosphonium ionic liquids for in situ catalysis.

PubMed

Banerjee, Abhinandan; Theron, Robin; Scott, Robert W J

2012-01-09

Gold and palladium nanoparticles were prepared by lithium borohydride reduction of the metal salt precursors in tetraalkylphosphonium halide ionic liquids in the absence of any organic solvents or external nanoparticle stabilizers. These colloidal suspensions remained stable and showed no nanoparticle agglomeration over many months. A combination of electrostatic interactions between the coordinatively unsaturated metal nanoparticle surface and the ionic-liquid anions, bolstered by steric protection offered by the bulky alkylated phosphonium cations, is likely to be the reason behind such stabilization. The halide anion strongly absorbs to the nanoparticle surface, leading to exceptional nanoparticle stability in halide ionic liquids; other tetraalkylphosphonium ionic liquids with non-coordinating anions, such as tosylate and hexafluorophosphate, show considerably lower affinities towards the stabilization of nanoparticles. Palladium nanoparticles stabilized in the tetraalkylphosphonium halide ionic liquid were stable, efficient, and recyclable catalysts for a variety of hydrogenation reactions at ambient pressures with sustained activity. Aerial oxidation of the metal nanoparticles occurred over time and was readily reversed by re-reduction of oxidized metal salts. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Extraction and Esterification of Low-Titer Short-Chain Volatile Fatty Acids from Anaerobic Fermentation with Ionic Liquids.

PubMed

Andersen, Stephen J; Berton, Jan K E T; Naert, Pieter; Gildemyn, Sylvia; Rabaey, Korneel; Stevens, Christian V

2016-08-23

Ionic liquids can both act as a solvent and mediate esterification to valorize low-titer volatile fatty acids and generate organic solvents from renewable carbon sources including biowaste and CO2 . In this study, four phosphonium ionic liquids were tested for single-stage extraction of acetic acid from a dilute stream and esterification to ethyl acetate with added ethanol and heat. The esterification proceeded with a maximum conversion of 85.9±1.3 % after 30 min at 75 °C at a 1:1 stoichiometric ratio of reactants. Extraction and esterification can be tailored using mixed-anion ionic liquids; this is demonstrated herein using a common trihexyl(tetradecyl)phosphonium cation and a mixed chloride and bis(trifluoromethylsulfonyl)imide anion ionic liquid. As a further proof-of-concept, ethyl acetate was generated from an ionic liquid-driven esterification of an acetic acid extractant generated using CO2 as the only carbon source by microbial electrosynthesis. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mapping the pharmaceutical design space by amorphous ionic liquid strategies.

PubMed

Wiest, Johannes; Saedtler, Marco; Balk, Anja; Merget, Benjamin; Widmer, Toni; Bruhn, Heike; Raccuglia, Marc; Walid, Elbast; Picard, Franck; Stopper, Helga; Dekant, Wolfgang; Lühmann, Tessa; Sotriffer, Christoph; Galli, Bruno; Holzgrabe, Ulrike; Meinel, Lorenz

2017-12-28

Poor water solubility of drugs fuels complex formulations and jeopardizes patient access to medication. Simplifying these complexities we systematically synthesized a library of 36 sterically demanding counterions and mapped the pharmaceutical design space for amorphous ionic liquid strategies for Selurampanel, a poorly water soluble drug used against migraine. Patients would benefit from a rapid uptake after oral administration to alleviate migraine symptoms. Therefore, we probed the ionic liquids for the flux, supersaturation period and hygroscopicity leading to algorithms linking molecular counterion descriptors to predicted pharmaceutical outcome. By that, 30- or 800-fold improvements of the supersaturation period and fluxes were achieved as were immediate to sustained release profiles through structural counterions' optimization compared to the crystalline free acid of Selurampanel. Guided by ionic liquid structure, in vivo profiles ranged from rapid bioavailability and high maximal plasma concentrations to sustained patterns. In conclusion, the study outlined and predicted the accessible pharmaceutical design space of amorphous ionic liquid based and excipient-free formulations pointing to the enormous pharmaceutical potential of ionic liquid designs. Copyright © 2017 Elsevier B.V. All rights reserved.

A Flemion-based actuator with ionic liquid as solvent

NASA Astrophysics Data System (ADS)

Wang, Jin; Xu, Chunye; Taya, Minoru; Kuga, Yasuo

2007-04-01

A perfluorinated carboxylic acid membrane, i.e. Flemion, shows improved performance as actuator material compared with Nafion (perfluorinated sulfonic acid). Flemion has a higher ion exchange capacity and good mechanical strength. In particular, Flemion will deform with no back relaxation under applied electrical stimulus. However, with water as solvent, the operation of Flemion in air has serious problems, since water would evaporate quickly in air. Moreover, the electrochemical stability for use in water is around 1 V at room temperature. In previous work, investigations on Nafion with ionic liquid as solvents have been carried out by some researchers and good results have been obtained. In this work, we explore the use of highly stable ionic liquid instead of water as solvent in Flemion. Experimental results indicate that Flemion-based actuators with ionic liquid as solvent have improved stability as compared to the water samples. Although the forces exhibited by Flemion-based actuators with the use of ionic liquid decreased dramatically compared to water, these preliminary results suggest good potential for the use of Flemion with ionic liquid in future applications.

Flemion-based actuator with ionic liquid as solvent

NASA Astrophysics Data System (ADS)

Wang, Jin; Xu, Chunye; Taya, Minoru; Kuga, Yasuo

2006-03-01

A perfluorinated carboxylic acid membrane, i.e. Flemion, shows improved performance as actuator material compared with Nafion (perfluorinated sulfonic acide). Flemion has a higher ion exchange capacity and good mechanical strength. Especially, Flemion will deform with no back relaxation when applied electrical stimulus. However, with water as solvent, the operation of Flemion in air has serious problems. Since water would evaporate quickly in air. Moreover, the electrochemical stability for use in water is around 1V at room temperature. In previous work, investigations on Nafion with ionic liquid as solvents have been carried out and good results have been obtained. In this work, we explore the use of highly stable ionic liquid instead of water as solvent in Flemion. Experimental results indicate that Flemion based actuators with ionic liquid as solvent have improved stability as compared to the water samples. Although the forces exhibited by Flemion based actuators with the use of ionic liquid decreased dramatically as compared to water, these preliminary results suggest a good potential for use of Flemion with ionic liquid in some applications.

Global transcriptome response to ionic liquid by a tropical rain forest soil bacterium, Enterobacter lignolyticus.

PubMed

Khudyakov, Jane I; D'haeseleer, Patrik; Borglin, Sharon E; Deangelis, Kristen M; Woo, Hannah; Lindquist, Erika A; Hazen, Terry C; Simmons, Blake A; Thelen, Michael P

2012-08-07

To process plant-based renewable biofuels, pretreatment of plant feedstock with ionic liquids has significant advantages over current methods for deconstruction of lignocellulosic feedstocks. However, ionic liquids are often toxic to the microorganisms used subsequently for biomass saccharification and fermentation. We previously isolated Enterobacter lignolyticus strain SCF1, a lignocellulolytic bacterium from tropical rain forest soil, and report here that it can grow in the presence of 0.5 M 1-ethyl-3-methylimidazolium chloride, a commonly used ionic liquid. We investigated molecular mechanisms of SCF1 ionic liquid tolerance using a combination of phenotypic growth assays, phospholipid fatty acid analysis, and RNA sequencing technologies. Potential modes of resistance to 1-ethyl-3-methylimidazolium chloride include an increase in cyclopropane fatty acids in the cell membrane, scavenging of compatible solutes, up-regulation of osmoprotectant transporters and drug efflux pumps, and down-regulation of membrane porins. These findings represent an important first step in understanding mechanisms of ionic liquid resistance in bacteria and provide a basis for engineering microbial tolerance.

Magnetical hollow fiber bar collection of extract in homogenous ionic liquid microextraction of triazine herbicides in water samples.

PubMed

Wang, Kun; Jiang, Jia; Kang, Mingqin; Li, Dan; Zang, Shuang; Tian, Sizhu; Zhang, Hanqi; Yu, Aimin; Zhang, Ziwei

2017-04-01

The homogeneous ionic liquid microextraction combined with magnetical hollow fiber bar collection was developed for extracting triazine herbicides from water samples. These analytes were separated and determined by high performance liquid chromatography. The triazines were quickly extracted into ionic liquid microdroplets dispersed in solution, and then these microdroplets were completely collected with magnetical hollow fiber bars; the pores of which were impregnated with hydrophobic ionic liquid, which makes the phase separation simplified with no need of centrifugation. Some experimental parameters, such as the type of ionic liquid, ultrasonic immersion time of hollow fiber, pH of sample solution, volume of hydrophilic ionic liquid, amount of ion-pairing agent NH 4 PF 6 , NaCl concentration, number of magnetical hollow fiber bar, stirring rate, and collection time were investigated and optimized. When the present method was applied to the analysis of real water samples, the precision and recoveries of six triazine herbicides vary from 0.1 to 9.2% and 73.4 to 118.5%, respectively. The detection limits for terbumeton, ametryn, prometryn, terbutryn, trietazine, and dimethametryn were 0.48, 0.15, 0.15, 0.14, 0.35, and 0.16 μg L -1 , respectively.

Water Contaminant Mitigation in Ionic Liquid Propellant

NASA Technical Reports Server (NTRS)

Conroy, David; Ziemer, John

2009-01-01

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

Ionic liquids gels: Soft materials for environmental remediation.

PubMed

Marullo, Salvatore; Rizzo, Carla; Dintcheva, Nadka T; Giannici, Francesco; D'Anna, Francesca

2018-05-01

Nanostructured sorbents and, in particular, supramolecular gels are emerging as efficient materials for the removal of toxic contaminants from water, like industrial dyes. It is also known that ionic liquids can dissolve significant amounts of dyes. Consequently, supramolecular ionic liquids gels could be highly efficient sorbents for dyes removal. This would also contribute to overcome the drawbacks associated with dye removal by liquid-liquid extraction with neat ionic liquids which would require large volumes of extractant and a more difficult separation of the phases. Herein we employed novel supramolecular ionic liquid gels based on diimidazolium salts bearing naturally occurring or biomass derived anions, to adsorb cationic and anionic dyes from wastewaters. We also carried out a detailed investigation of thermal, structural, morphological and rheological features of our gels to identify which of them are key in designing better sorbents for environmental remediation. The most effective gels showed fast and thorough removal of cationic dyes like Rhodamine B. These gels could also be reused up to 20 times without any loss in removal efficiency. Overall, our ionic gels outperform most of gel-based sorbents systems so far reported in literature. Copyright © 2018 Elsevier Inc. All rights reserved.

Block Copolymers and Ionic Liquids: A New Class of Functional Nanocomposites

NASA Astrophysics Data System (ADS)

Lodge, Timothy

2009-03-01

Block copolymers provide a remarkably versatile platform for achieving desired nanostructures by self-assembly, with lengthscales varying from a few nanometers up to several hundred nanometers. Ionic liquids are an emerging class of solvents, with an appealing set of physical attributes. These include negligible vapor pressure, high chemical and thermal stability, tunable solvation properties, high ionic conductivity, and wide electrochemical windows. For various applications it will be necessary to solidify the ionic liquid into particular spatial arrangements, such as membranes or gels, or to partition the ionic liquid in coexisting phases, such as microemulsions and micelles. One example includes formation of spherical, cylindrical, and vesicular micelles by poly(butadiene-b-ethylene oxide) and poly(styrene-b-methylmethacrylate) in the common hydrophobic ionic liquids [BMI][PF6] and [EMI][TFSI]. This work has been extended to the formation of reversible micelle shuttles between ionic liquids and water, whereby entire micelles transfer from one phase to the other, reversibly, depending on temperature and solvent quality. Formation of ion gels has been achieved by self-assembly of poly(styrene-b-ethylene oxide-b-styrene) triblocks in ionic liquids, and by the thermoreversible system poly(N-isopropylacrylamide-b-ethylene oxide-b-N-isopropylacrylamide), using as little as 4% copolymer. Further, these gels have been shown to be remarkably effective as gate dielectrics in organic thin film transistors. The remarkably high capacitance of the ion gels (> 10 μF/cm^2) supports a very high carrier density in an organic semiconductor such as poly(3-hexylthiophene), leading to milliamp currents for low applied voltages. Furthermore, the rapid mobility of the ions enables switching speeds approaching 10 kHz, orders of magnitude higher than achievable with other polymer-based dielectrics such as PEO/LiClO4. Finally, we have shown that ordered nanostructures of block copolymers plus ionic liquids show the characteristic self-assembly properties of strongly-segregated systems. Prospects for anisotropic ionic conductivity are also being explored.

Synthesis of hetero compounds using dialkylcarbonate quaternation

DOEpatents

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

2017-10-17

Methods of preparing hetero ionic complexes, and ionic liquids from bisulfate salts of heteroatomic compounds using dialkylcarbonates as a primary quaternizing reactant are disclosed. Also disclosed are methods of making electrochemical cells comprising the ionic liquids, and an electrochemical cell comprising an alkaline electrolyte and a hetero ionic complex additive.

Ionic liquids at the surface of graphite: Wettability and structure

NASA Astrophysics Data System (ADS)

Bordes, Emilie; Douce, Laurent; Quitevis, Edward L.; Pádua, Agílio A. H.; Costa Gomes, Margarida

2018-05-01

The aim of this work is to provide a better understanding of the interface between graphite and different molecular and ionic liquids. Experimental measurements of the liquid surface tension and of the graphite-liquid contact angle for sixteen ionic liquids and three molecular liquids are reported. These experimental values allowed the calculation of the solid/liquid interfacial energy that varies, for the ionic liquids studied, between 14.5 mN m-1 for 1-ethyl-3-methylimidazolium dicyanamide and 37.8 mN m-1 for 3-dodecyl-1-(naphthalen-1-yl)-1H-imidazol-3-ium tetrafluoroborate. Imidazolium-based ionic liquids with large alkyl side-chains or functionalized with benzyl groups seem to interact more favourably with freshly peeled graphite surfaces. Even if the interfacial energy seems a good descriptor to assess the affinity of a liquid for a carbon-based solid material, we conclude that both the surface tension of the liquid and the contact angle between the liquid and the solid can be significant. Molecular dynamics simulations were used to investigate the ordering of the ions near the graphite surface. We conclude that the presence of large alkyl side-chains in the cations increases the ordering of ions at the graphite surface. Benzyl functional groups in the cations lead to a large affinity towards the graphite surface.

Ionic Liquid-Based Optical and Electrochemical Carbon Dioxide Sensors.

PubMed

Behera, Kamalakanta; Pandey, Shubha; Kadyan, Anu; Pandey, Siddharth

2015-12-04

Due to their unusual physicochemical properties (e.g., high thermal stability, low volatility, high intrinsic conductivity, wide electrochemical windows and good solvating ability), ionic liquids have shown immense application potential in many research areas. Applications of ionic liquid in developing various sensors, especially for the sensing of biomolecules, such as nucleic acids, proteins and enzymes, gas sensing and sensing of various important ions, among other chemosensing platforms, are currently being explored by researchers worldwide. The use of ionic liquids for the detection of carbon dioxide (CO₂) gas is currently a major topic of research due to the associated importance of this gas with daily human life. This review focuses on the application of ionic liquids in optical and electrochemical CO₂ sensors. The design, mechanism, sensitivity and detection limit of each type of sensor are highlighted in this review.

Ionic liquids in tribology.

PubMed

Minami, Ichiro

2009-06-24

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

Modeling electrokinetics in ionic liquids: General

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Chao; Bao, Jie; Pan, Wenxiao

2017-04-07

Using direct numerical simulations we provide a thorough study on the electrokinetics of ionic liquids. In particular, the modfied Poisson-Nernst-Planck (MPNP) equations are solved to capture the crowding and overscreening effects that are the characteristics of an ionic liquid. For modeling electrokinetic flows in an ionic liquid, the MPNP equations are coupled with the Navier-Stokes equations to study the coupling of ion transport, hydrodynamics, and electrostatic forces. Specifically, we consider the ion transport between two parallel plates, charging dynamics in a 2D straight-walled pore, electro-osmotic ow in a nano-channel, electroconvective instability on a plane ion-selective surface, and electroconvective ow onmore » a curved ion-selective surface. We discuss how the crowding and overscreening effects and their interplay affect the electrokinetic behaviors of ionic liquids in these application problems.« less

Ionic Liquid-Based Optical and Electrochemical Carbon Dioxide Sensors

PubMed Central

Behera, Kamalakanta; Pandey, Shubha; Kadyan, Anu; Pandey, Siddharth

2015-01-01

Due to their unusual physicochemical properties (e.g., high thermal stability, low volatility, high intrinsic conductivity, wide electrochemical windows and good solvating ability), ionic liquids have shown immense application potential in many research areas. Applications of ionic liquid in developing various sensors, especially for the sensing of biomolecules, such as nucleic acids, proteins and enzymes, gas sensing and sensing of various important ions, among other chemosensing platforms, are currently being explored by researchers worldwide. The use of ionic liquids for the detection of carbon dioxide (CO2) gas is currently a major topic of research due to the associated importance of this gas with daily human life. This review focuses on the application of ionic liquids in optical and electrochemical CO2 sensors. The design, mechanism, sensitivity and detection limit of each type of sensor are highlighted in this review. PMID:26690155

Rapid analysis of ultraviolet filters using dispersive liquid-liquid microextraction coupled to headspace gas chromatography and mass spectrometry.

PubMed

Pierson, Stephen A; Trujillo-Rodríguez, María J; Anderson, Jared L

2018-05-29

An ionic-liquid-based in situ dispersive liquid-liquid microextraction method coupled to headspace gas chromatography and mass spectrometry was developed for the rapid analysis of ultraviolet filters. The chemical structures of five ionic liquids were specifically designed to incorporate various functional groups for the favorable extraction of the target analytes. Extraction parameters including ionic liquid mass, molar ratio of ionic liquid to metathesis reagent, vortex time, ionic strength, pH, and total sample volume were studied and optimized. The effect of the headspace temperature and volume during the headspace sampling step was also evaluated to increase the sensitivity of the method. The optimized procedure is fast as it only required ∼7-10 min per extraction and allowed for multiple extractions to be performed simultaneously. In addition, the method exhibited high precision, good linearity, and low limits of detection for six ultraviolet filters in aqueous samples. The developed method was applied to both pool and lake water samples attaining acceptable relative recovery values. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

PubMed

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

2014-09-01

A novel on-line three-dimensional liquid chromatography method was developed to separate four main flavonoids from Rhodiola rosea. Ethyl acetate/0.5 mol/L ionic liquid 1-butyl-3-methylimidazolium chloride aqueous solution was selected as the solvent system. In the first-dimension separation, the target flavonoids were entrapped and subsequently desorbed into the second-dimension high-speed countercurrent chromatographic column for separation. In the third-dimension chromatography, the residual ionic liquid in the four separated flavonoids was removed and the used ionic liquid was recovered. As a result, 35.1 mg of compound 1, 20.4 mg of compound 2, 8.5 mg of compound 3, and 10.6 mg of compound 4 were obtained from 1.53 g R. rosea extract. They were identified as rhodiosin, rhodionin, herbacetin, and kaempferol, respectively. The recovery of ionic liquid reached 99.1% of the initial amount. The results showed that this method is a powerful technology for the separation of R. rosea flavonoids and that the ionic-liquid-based solvent system has advantages over traditional solvent systems in renewable and environmentally friendly properties. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Lattice model of ionic liquid confined by metal electrodes

NASA Astrophysics Data System (ADS)

Girotto, Matheus; Malossi, Rodrigo M.; dos Santos, Alexandre P.; Levin, Yan

2018-05-01

We study, using Monte Carlo simulations, the density profiles and differential capacitance of ionic liquids confined by metal electrodes. To compute the electrostatic energy, we use the recently developed approach based on periodic Green's functions. The method also allows us to easily calculate the induced charge on the electrodes permitting an efficient implementation of simulations in a constant electrostatic potential ensemble. To speed up the simulations further, we model the ionic liquid as a lattice Coulomb gas and precalculate the interaction potential between the ions. We show that the lattice model captures the transition between camel-shaped and bell-shaped capacitance curves—the latter characteristic of ionic liquids (strong coupling limit) and the former of electrolytes (weak coupling). We observe the appearance of a second peak in the differential capacitance at ≈0.5 V for 2:1 ionic liquids, as the packing fraction is increased. Finally, we show that ionic size asymmetry decreases substantially the capacitance maximum, when all other parameters are kept fixed.

Gas chromatography on wall-coated open-tubular columns with ionic liquid stationary phases.

PubMed

Poole, Colin F; Lenca, Nicole

2014-08-29

Ionic liquids have moved from novel to practical stationary phases for gas chromatography with an increasing portfolio of applications. Ionic liquids complement conventional stationary phases because of a combination of thermophysical and solvation properties that only exist for ionic solvents. Their high thermal stability and low vapor pressure makes them suitable as polar stationary phases for separations requiring high temperatures. Ionic liquids are good solvents and can be used to expand the chemical space for separations. They are the only stationary phases with significant hydrogen-bond acidity in common use; they extend the hydrogen-bond basicity of conventional stationary phases; they are as dipolar/polarizable as the most polar conventional stationary phases; and some ionic liquids are significantly less cohesive than conventional polar stationary phases. Problems in column coating techniques and related low column performance, column activity, and stationary phase reactivity require further exploration as the reasons for these features are poorly understood at present. Copyright © 2014 Elsevier B.V. All rights reserved.

Femtosecond Raman-Induced Kerr Effect Study of Temperature-Dependent Intermolecular Dynamics in Molten Bis(trifluoromethylsulfonyl)amide Salts: Effects of Cation Species.

PubMed

Kakinuma, Shohei; Shirota, Hideaki

2018-05-25

In this study, we have investigated the effects of cation structures on the temperature dependence of the intermolecular vibrational dynamics of ionic liquids using femtosecond Raman-induced Kerr effect spectroscopy. The ionic liquids used in this study are bis(trifluoromethylsulfonyl)amide [NTf 2 ] - salts of the cations 1-butyl-3-methylimidazolium [C 4 MIm] + , 1-butyl-1-methylpyrrolidinium [Pyrr 14 ] + , 1-butylpyridinium [C 4 Py] + , butyldiethylmethylammonium [N 1224 ] + , triethyloctylammonium [N 2228 ] + , and triethyloctylphosphonium [P 2228 ] + . All of the ionic liquids show temperature-dependent low-frequency spectra. A difference in the temperature dependence between the spectra of the aromatic and nonaromatic cation based ionic liquids is especially significant. In the case of the aromatic cation based ionic liquids [C 4 MIm][NTf 2 ] and [C 4 Py][NTf 2 ], the spectral intensities in the low-frequency region below ca. 50 cm -1 increase and the high-frequency components at ca. 80 cm -1 shift to lower frequencies with rising temperature. In contrast, the ionic liquids based on nonaromatic cations only exhibit an increase in the low-frequency region below ca. 50 cm -1 with increasing temperature, while the high-frequency region of the spectra above ca. 50 cm -1 shows little change with variation of the temperature. These results suggest that the presence or absence of aromatic rings is the main factor in determining the temperature-dependent spectral features, particularly in the high-frequency region. We also found that the alkyl chain length and central atoms of the nonaromatic quaternary cations do not have much influence on the temperature-dependent spectral features. The first moments of the aromatic cation based ionic liquids are a little more sensitive to temperature than those of the nonaromatic cation based ionic liquids. The temperature-dependent viscosities and fragilities of the ionic liquids have also been examined.

Surface polymerization of (3,4-ethylenedioxythiophene) probed by in situ scanning tunneling microscopy on Au(111) in ionic liquids

NASA Astrophysics Data System (ADS)

Ahmad, Shahzada; Carstens, Timo; Berger, Rüdiger; Butt, Hans-Jürgen; Endres, Frank

2011-01-01

The electropolymerization of 3,4-ethylenedioxythiophene (EDOT) to poly(3,4-ethylenedioxythiophene) (PEDOT) was investigated in the air and water-stable ionic liquids 1-hexyl-3-methylimidazolium tris(pentafluoroethyl) trifluorophosphate [HMIm]FAP and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) amide [EMIm]TFSA. In situscanning tunnelling microscopy (STM) results show that the electropolymerization of EDOT in the ionic liquid can be probed on the nanoscale. In contrast to present understanding, it was observed that the EDOT can be oxidised in ionic liquids well below its oxidation potential and the under potential growth of polymer was visualized by in situSTM. These results serve as the first study to confirm the under potential growth of conducting polymers in ionic liquids. Furthermore, ex situmicroscopy measurements were performed. Quite a high current of 670 nA was observed on the nanoscale by conductive scanning force microscopy (CSFM).The electropolymerization of 3,4-ethylenedioxythiophene (EDOT) to poly(3,4-ethylenedioxythiophene) (PEDOT) was investigated in the air and water-stable ionic liquids 1-hexyl-3-methylimidazolium tris(pentafluoroethyl) trifluorophosphate [HMIm]FAP and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) amide [EMIm]TFSA. In situscanning tunnelling microscopy (STM) results show that the electropolymerization of EDOT in the ionic liquid can be probed on the nanoscale. In contrast to present understanding, it was observed that the EDOT can be oxidised in ionic liquids well below its oxidation potential and the under potential growth of polymer was visualized by in situSTM. These results serve as the first study to confirm the under potential growth of conducting polymers in ionic liquids. Furthermore, ex situmicroscopy measurements were performed. Quite a high current of 670 nA was observed on the nanoscale by conductive scanning force microscopy (CSFM). Electronic supplementary information (ESI) available: In situ image of PEDOT in [HMIm]FAP and in situ studies of PEDOT grown in [EMIm]TFSA and redox behavior of PEDOT. See DOI: 10.1039/c0nr00579g

Method and apparatus for processing algae

DOEpatents

Chew, Geoffrey; Reich, Alton J.; Dykes, Jr., H. Waite; Di Salvo, Roberto

2012-07-03

Methods and apparatus for processing algae are described in which a hydrophilic ionic liquid is used to lyse algae cells. The lysate separates into at least two layers including a lipid-containing hydrophobic layer and an ionic liquid-containing hydrophilic layer. A salt or salt solution may be used to remove water from the ionic liquid-containing layer before the ionic liquid is reused. The used salt may also be dried and/or concentrated and reused. The method can operate at relatively low lysis, processing, and recycling temperatures, which minimizes the environmental impact of algae processing while providing reusable biofuels and other useful products.

"Nonsolvent" applications of ionic liquids in biotransformations and organocatalysis.

PubMed

Domínguez de María, Pablo

2008-01-01

The application of room-temperature ionic liquids (RTILs) as (co)solvents and/or reagents is well documented. However, RTILS also have "nonsolvent" applications in biotransformations and organocatalysis. Examples are the anchoring of substrates to RTILs; ionic-liquid-coated enzymes (ILCE) and enzyme-IL colyophilization; the construction of biocatalytic ternary reaction systems; the combination of enzymes, RTILs, membranes, and (bio)electrochemistry; and ionic-liquid-supported organocatalysts. These strategies provide more robust, more efficient, and more enantioselective bio- and organocatalysts with many practical applications. As shown herein, RTILs offer a wide range of promising alternatives to conventional chemistry.

Dispersion polymerization of L-lactide utilizing ionic liquids as reaction medium

NASA Astrophysics Data System (ADS)

Fahmiati, Sri; Minami, Hideto; Haryono, Agus; Adilina, Indri B.

2017-11-01

Dispersion polymerization of L-lactide was proceeded in various ionic liquids. Ionic liquids as 1-Hexyl-3-methylimidazolium bis (trifluormethylsulfonyl) imide, [HMIM] [TFSI], 1-Butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide, [BMP] [TFSI], and N,N,N-Trimethyl-N-Propylammonium Bis (trifloromethanesulfonyl) imide, [TMPA] [TFSI], were employed as reaction medium that dissolved both of lactide and stabilizer (polyvinylprrolidone). Sn-supported on bentonite was used as a ring opening catalyst of L-lactide. Gel Permeation Chromatography result showed that poly-(L-lactic acid) were formed in ionic liquids [HMIM] [TFSI] and [BMP] [TFSI] with molecular weight as 19390 and 20844, respectively.

Effect of Cerium(III) and ionic liquids on the clouding behavior of Triton X-100 micelles

NASA Astrophysics Data System (ADS)

Sen, Indrani Das; Negi, Charu; Jayaram, Radha V.

2018-04-01

In the present study, the effect of Ce(III) on the clouding behavior of Triton X-100 has been investigated in the presence and absence of imidazolium based ionic liquids of varying chain length and counter ions. Thermodynamic parameters of clouding were calculated to comprehend the underlying interactions between the surfactant and the additives. The cloud point (CP) of Triton X-100 was found to increase with the concentration of Ce(III) and that of the ionic liquids studied. This increase of CP reflects the solubilization of the ionic liquids in the micellar solution1.

Key Developments in Ionic Liquid Crystals.

PubMed

Alvarez Fernandez, Alexandra; Kouwer, Paul H J

2016-05-16

Ionic liquid crystals are materials that combine the classes of liquid crystals and ionic liquids. The first one is based on the multi-billion-dollar flat panel display industry, whilst the latter quickly developed in the past decades into a family of highly-tunable non-volatile solvents. The combination yields materials with a unique set of properties, but also with many challenges ahead. In this review, we provide an overview of the key concepts in ionic liquid crystals, particularly from a molecular perspective. What are the important molecular parameters that determine the phase behavior? How should they be introduced into the molecules? Finally, which other tools does one have to realize specific properties in the material?

Key Developments in Ionic Liquid Crystals

PubMed Central

Alvarez Fernandez, Alexandra; Kouwer, Paul H. J.

2016-01-01

Ionic liquid crystals are materials that combine the classes of liquid crystals and ionic liquids. The first one is based on the multi-billion-dollar flat panel display industry, whilst the latter quickly developed in the past decades into a family of highly-tunable non-volatile solvents. The combination yields materials with a unique set of properties, but also with many challenges ahead. In this review, we provide an overview of the key concepts in ionic liquid crystals, particularly from a molecular perspective. What are the important molecular parameters that determine the phase behavior? How should they be introduced into the molecules? Finally, which other tools does one have to realize specific properties in the material? PMID:27196890

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

PubMed

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

2015-06-17

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

The radiation chemistry of ionic liquids: A review

DOE PAGES

Mincher, Bruce J.; Wishart, James F.

2014-07-03

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

Quantification of amino acids and peptides in an ionic liquid based aqueous two-phase system by LC-MS analysis.

PubMed

Oppermann, Sebastian; Oppermann, Christina; Böhm, Miriam; Kühl, Toni; Imhof, Diana; Kragl, Udo

2018-04-25

Aqueous two-phase systems (ATPS) occur by the mixture of two polymers or a polymer and an inorganic salt in water. It was shown that not only polymers but also ionic liquids in combination with inorganic cosmotrophic salts are able to build ATPS. Suitable for the formation of ionic liquid-based ATPS systems are hydrophilic water miscible ionic liquids. To understand the driving force for amino acid and peptide distribution in IL-ATPS at different pH values, the ionic liquid Ammoeng 110™ and K 2 HPO 4 have been chosen as a test system. To quantify the concentration of amino acids and peptides in the different phases, liquid chromatography and mass spectrometry (LC-MS) technologies were used. Therefore the peptides and amino acids have been processed with EZ:faast™-Kit from Phenomenex for an easy and reliable quantification method even in complex sample matrices. Partitioning is a surface-dependent phenomenon, investigations were focused on surface-related amino acid respectively peptide properties such as charge and hydrophobicity. Only a very low dependence between the amino acids or peptides hydrophobicity and the partition coefficient was found. Nevertheless, the presented results show that electrostatic respectively ionic interactions between the ionic liquid and the amino acids or peptides have a strong impact on their partitioning behavior.

A review of the structure and dynamics of nanoconfined water and ionic liquids via molecular dynamics simulation.

PubMed

Foroutan, Masumeh; Fatemi, S Mahmood; Esmaeilian, Farshad

2017-02-01

During the past decade, the research on fluids in nanoconfined geometries has received considerable attention as a consequence of their wide applications in different fields. Several nanoconfined systems such as water and ionic liquids, together with an equally impressive array of nanoconfining media such as carbon nanotube, graphene and graphene oxide have received increasingly growing interest in the past years. Water is the first system that has been reviewed in this article, due to its important role in transport phenomena in environmental sciences. Water is often considered as a highly nanoconfined system, due to its reduction to a few layers of water molecules between the extended surface of large macromolecules. The second system discussed here is ionic liquids, which have been widely studied in the modern green chemistry movement. Considering the great importance of ionic liquids in industry, and also their oil/water counterpart, nanoconfined ionic liquid system has become an important area of research with many fascinating applications. Furthermore, the method of molecular dynamics simulation is one of the major tools in the theoretical study of water and ionic liquids in nanoconfinement, which increasingly has been joined with experimental procedures. In this way, the choice of water and ionic liquids in nanoconfinement is justified by applying molecular dynamics simulation approaches in this review article.

High energy supercapattery with an ionic liquid solution of LiClO4.

PubMed

Yu, Linpo; Chen, George Z

2016-08-15

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

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

PubMed

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

2014-02-20

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

A reversible conductivity modulation of azobenzene-based ionic liquids in aqueous solutions using UV/vis light.

PubMed

Li, Zhiyong; Yuan, Xiaoqing; Feng, Ying; Chen, Yongkui; Zhao, Yuling; Wang, Huiyong; Xu, Qingli; Wang, Jianji

2018-05-09

Photo-induced conductivity modulation of stimuli-responsive materials is of great importance from the viewpoint of fundamental research and technology. In this work, 5 new kinds of azobenzene-based photo-responsive ionic liquids were synthesized and characterized, and UV/vis light modulation of their conductivity was investigated in an aqueous solution. The factors affecting the conductivity modulation of the photo-responsive fluids, such as photo-isomerization efficiency, photo-regulation aggregation, concentration and chemical structure of the ionic liquids, were examined systematically. It was found that the conductivity of the ionic liquids in water exhibited a significant increase upon UV light irradiation and the ionic liquids with a shorter alkyl spacer in the cation showed a more remarkable photo-induced conductivity enhancement with a maximum increase of 150%. In addition, the solution conductivity was restored (or very close) to the initial value upon an alternative irradiation with visible light. Thus, the solution conductivity can be modulated using alternative irradiation with UV and visible light. Although the reversible photo-isomerization of the azobenzene group under UV/vis irradiation is the origin of the conductivity modulation, the photo-regulated aggregation of the ionic liquid in water is indispensable for the maximum degree of conductivity modulation because UV irradiation can weaken, even break the aggregated cis-isomers of the ionic liquids in an aqueous solution.

Determination of chlorophenols in honey samples using in-situ ionic liquid-dispersive liquid-liquid microextraction as a pretreatment method followed by high-performance liquid chromatography.

PubMed

Fan, Chen; Li, Nai; Cao, Xueli

2015-05-01

In-situ ionic liquid-dispersive liquid-liquid microextraction (IL-DLLME) method was developed as a pretreatment method for the detection of six chlorophenols (CPs) in honey samples. The hydrophobic ionic liquid [C4MIM][NTf2], formed in-situ by the hydrophilic ionic liquid [C4MIM][BF4] and the ion exchange reagent LiNTf2 was used as the microextractant solvent of CPs from honey sample. Then the enriched analytes were back-extracted into 40 μL of 0.14 M NaOH solution and finally subjected to analysis by high-performance liquid chromatography. The method showed low limit of detection of CPs, 0.8-3.2 μg/L and high enrichment factor, 34-65 with the recoveries range from 91.60% to 114.33%. The method is simple, rapid, environmentally friendly and with high extraction efficiency. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Mutual solubility of water and structural/positional isomers of N-alkylpyridinium-based ionic liquids.

PubMed

Freire, Mara G; Neves, Catarina M S S; Shimizu, Karina; Bernardes, Carlos E S; Marrucho, Isabel M; Coutinho, João A P; Canongia Lopes, José N; Rebelo, Luís Paulo N

2010-12-09

Despite many previous important contributions to the characterization of the liquid-liquid phase behavior of ionic liquids (ILs) plus water systems, a gap still exists as far as the effect of isomers (of ILs) is concerned. Therefore, in this work, a comprehensive study of the liquid-liquid equilibria between water and isomeric pyridinium-based ionic liquids has been performed. Atmospheric pressure mutual solubilities between water and pyridinium-based ionic liquids combined with the common anion bis[(trifluoromethyl)sulfonyl]imide were experimentally determined between (288.15 and 318.15) K. The main goal of this work is to study the isomeric effects on the pyridinium-based cation, namely, the structural and positional isomerism, as well as the alkyl side chain length. To the best of our knowledge, the influence of both structural and positional isomerism on the liquid-liquid behavior in ionic-liquid-water-containing systems is an unexplored field and is here assessed for the first time. Moreover, from the experimental solubility data, several infinite dilution molar thermodynamic functions of solution, namely, the Gibbs energy, the enthalpy, and the entropy, were estimated and discussed. In addition, aiming at gathering a broader picture of the underlying thermodynamic solvation phenomenon, molecular dynamics simulations were also carried out for the same experimental systems.

Highlights from the Faraday Discussion on Ionic Liquids: From Fundamental Properties to Practical Applications, Cambridge, UK, September 2017.

PubMed

Aldous, Leigh; Bendova, Magdalena; Gonzalez-Miquel, Maria; Swadźba-Kwaśny, Małgorzata

2018-05-22

For the third time, a Faraday Discussion addressed ionic liquids. Encompassing the wealth of research in this field, the contributions ranged from fundamental insights to the diverse applications of ionic liquids. Lively discussions initiated in the lecture hall and during poster sessions then seamlessly continued during the social program.

A Molecular Dynamics Study on Selective Cation Depletion from an Ionic Liquid Droplet under an Electric Field

NASA Astrophysics Data System (ADS)

Yang, Yudong; Ahn, Myungmo; Im, Dojin; Oh, Jungmin; Kang, Inseok

2017-11-01

General electrohydrodynamic behavior of ionic liquid droplets under an electric field is investigated using MD simulations. Especially, a unique behavior of ion depletion of an ionic liquid droplet under a uniform electric field is studied. Shape deformation due to electric stress and ion distributions inside the droplet are calculated to understand the ionic motion of imidazolium-based ionic liquid droplets with 200 ion pairs of 2 kinds of ionic liquids: EMIM-NTf2 and EMIM-ES. The intermolecular force between cations and anions can be significantly different due to the nature of the structure and charge distribution of the ions. Together with an analytical interpretation of the conducting droplet in an electric field, the MD simulation successfully explains the mechanism of selective ion depletion of an ionic liquid droplet in an electric field. The selective ion depletion phenomenon has been adopted to explain the experimentally observed retreating motion of a droplet in a uniform electric field. The effect of anions on the cation depletion phenomenon can be accounted for from a direct approach to the intermolecular interaction. This research was supproted by the National Research Foundation of Korea (NRF) Grant funded by the Korea government (MSIP) (No. 2017R1D1A1B05035211).

Lewis Acidic Ionic Liquids.

PubMed

Brown, Lucy C; Hogg, James M; Swadźba-Kwaśny, Małgorzata

2017-08-21

Until very recently, the term Lewis acidic ionic liquids (ILs) was nearly synonymous with halometallate ILs, with a strong focus on chloroaluminate(III) systems. The first part of this review covers the historical context in which these were developed, speciation of a range of halometallate ionic liquids, attempts to quantify their Lewis acidity, and selected recent applications: in industrial alkylation processes, in supported systems (SILPs/SCILLs) and in inorganic synthesis. In the last decade, interesting alternatives to halometallate ILs have emerged, which can be divided into two sub-sections: (1) liquid coordination complexes (LCCs), still based on halometallate species, but less expensive and more diverse than halometallate ionic liquids, and (2) ILs with main-group Lewis acidic cations. The two following sections cover these new liquid Lewis acids, also highlighting speciation studies, Lewis acidity measurements, and applications.

Mechanisms of the Diffusion of Nonpolar Substances in a Hydrophilic Ionic Liquid

NASA Astrophysics Data System (ADS)

Atamas', N. A.

2018-01-01

The structural-dynamic features of ionic liquid-nonpolar substance systems are studied by means of molecular dynamics using Frenkel's fundamental theory of a liquid and the phonon theory of the thermodynamics of a liquid, in combination with the DL_POLY_4.05 software package. Argon, methane, and benzene molecules serve as the dissolved substances. Model concepts are proposed and analyzed to describe the diffusion of molecules of a dissolved substance in an ionic liquid. It is shown that an increase in the mass of the molecules of a dissolved nonpolar substance correlates with their mobility in a hydrophilic ionic liquid (IL). This determines the diffusion of the components of dmim+/Cl- IL solutions and is responsible for the anomalous behavior of the solubility of nonpolar substances in them.

Can the scaling behavior of electric conductivity be used to probe the self-organizational changes in solution with respect to the ionic liquid structure? The case of [C8MIM][NTf2].

PubMed

Paluch, Marian; Wojnarowska, Zaneta; Goodrich, Peter; Jacquemin, Johan; Pionteck, Jürgen; Hensel-Bielowka, Stella

2015-08-28

Electrical conductivity of the supercooled ionic liquid [C8MIM][NTf2], determined as a function of temperature and pressure, highlights strong differences in its ionic transport behavior between low and high temperature regions. To date, the crossover effect which is very well known for low molecular van der Waals liquids has been rarely described for classical ionic liquids. This finding highlights that the thermal fluctuations could be dominant mechanisms driving the dramatic slowing down of ion motions near Tg. An alternative way to analyze separately low and high temperature dc-conductivity data using a density scaling approach was then proposed. Based on which a common value of the scaling exponent γ = 2.4 was obtained, indicating that the applied density scaling is insensitive to the crossover effect. By comparing the scaling exponent γ reported herein along with literature data for other ionic liquids, it appears that γ decreases by increasing the alkyl chain length on the 1-alkyl-3-methylimidazolium-based ionic liquids. This observation may be related to changes in the interaction between ions in solution driven by an increase in the van der Waals type interaction by increasing the alkyl chain length on the cation. This effect may be related to changes in the ionic liquid nanostructural organization with the alkyl chain length on the cation as previously reported in the literature based on molecular dynamic simulations. In other words, the calculated scaling exponent γ may be then used as a key parameter to probe the interaction and/or self-organizational changes in solution with respect to the ionic liquid structure.

Proteomic alterations induced by ionic liquids in Aspergillus nidulans and Neurospora crassa.

PubMed

Martins, Isabel; Hartmann, Diego O; Alves, Paula C; Planchon, Sébastien; Renaut, Jenny; Leitão, M Cristina; Rebelo, Luís P N; Silva Pereira, Cristina

2013-12-06

This study constitutes the first attempt to understand at the proteomic level the fungal response to ionic liquid stress. Ascomycota are able to grow in media supplemented with high concentrations of an ionic liquid, which, in turn, lead to major alterations in the fungal metabolic footprint. Herein, we analysed the differential accumulation of mycelial proteins in Aspergillus nidulans and Neurospora crassa after their exposure to two of the most commonly used ionic liquids: 1-ethyl-3-methylimidazolium chloride or cholinium chloride. Data obtained showed that numerous stress-responsive proteins (e.g. anti-ROS defence proteins) as well as several critical biological processes and/or pathways were affected by either ionic liquid. Amongst other changes, these compounds altered developmental programmes in both fungi (e.g. promoting the development of Hülle cells or conidiation) and led to accumulation of osmolytes, some of which may play an important role in multiple stress responses. In particular, in N. crassa, both ionic liquids increased the levels of proteins which are likely involved in the biosynthesis of unusual metabolites. These data potentially open new perspectives on ionic liquid research, furthering their conscious design and their use to trigger production of targeted metabolites. The present study emphasises the importance of understanding ionic liquid's stress responses, crucial to further their safe large-scale usage. Knowledge of the alterations prompted at a cellular and biochemical level gives also fresh perspectives on how to employ these "novel" compounds to manipulate proteins or pathways of biotechnological value. The results presented here provide meaningful insights into the understanding of fungi stress and adaptation responses to anthropogenic chemicals used in industry. © 2013.

Ternary mixtures of ionic liquids for better salt solubility, conductivity and cation transference number improvement

PubMed Central

Karpierz, E.; Niedzicki, L.; Trzeciak, T.; Zawadzki, M.; Dranka, M.; Zachara, J.; Żukowska, G. Z.; Bitner-Michalska, A.; Wieczorek, W.

2016-01-01

We hereby present the new class of ionic liquid systems in which lithium salt is introduced into the solution as a lithium cation−glyme solvate. This modification leads to the reorganisation of solution structure, which entails release of free mobile lithium cation solvate and hence leads to the significant enhancement of ionic conductivity and lithium cation transference numbers. This new approach in composing electrolytes also enables even three-fold increase of salt concentration in ionic liquids. PMID:27767069

In-situ ionic liquid dispersive liquid-liquid microextraction using a new anion-exchange reagent combined Fe3O4 magnetic nanoparticles for determination of pyrethroid pesticides in water samples.

PubMed

Fan, Chen; Liang, You; Dong, Hongqiang; Ding, Guanglong; Zhang, Wenbing; Tang, Gang; Yang, Jiale; Kong, Dandan; Wang, Deng; Cao, Yongsong

2017-07-04

In this work, in-situ ionic liquid dispersive liquid-liquid microextraction combined ultrasmall Fe 3 O 4 magnetic nanoparticles was developed as a kind of pretreatment method to detect pyrethroid pesticides in water samples. New anion-exchange reagents including Na[DDTC] and Na[N(CN) 2 ] were optimized for in-situ extraction pyrethroids, which showed enhanced microextraction performance. Pyrethroids were enriched by hydrophilic ionic liquid [P 4448 ][Br] (aqueous solution, 200 μL, 0.2 mmol mL -1 ) reaction in-situ with anion-exchange reagent Na[N(CN) 2 ] (aqueous solution, 300 μL, 0.2 mmol mL -1 ) forming hydrophobic ionic liquid as extraction agent in water sample (10 mL). Ultrasmall superparamagnetic iron oxide nanoparticles (30 mg) were used to collect the mixture of ionic liquid and pyrethroids followed by elution with acetonitrile. The extraction of ionic liquid strategies was unique and efficiently fulfilled with high enrichment factors (176-213) and good recoveries (80.20-117.31%). The method was successively applied to the determination of pyrethroid pesticides in different kinds of water samples with the limits of detection ranged from 0.16 to 0.21 μg L -1 . The proposed method is actually nanometer-level microextraction (average size 80 nm) with the advantages of simplicity, rapidity, and sensitivity. Copyright © 2017 Elsevier B.V. All rights reserved.

Breaking the paradigm: Record quindecim charged magnetic ionic liquids

DOE PAGES

Prodius, D.; Smetana, V.; Steinberg, S.; ...

2016-12-08

A family of bis(trifluoromethanesulfonyl)amide-based ionic liquids of composition [RE 5(C 2H 5-C 3H 3N 2-CH 2COO) 16(H 2O) 8](Tf 2N) 15 (RE = Er, Ho, Tm; C 3H 3N 2 ≡ imidazolium moiety) featuring the cationic, record quindecim {15+} charged pentanuclear rare earth (RE)-containing ion [RE 5(C 2H 5-C 3H 3N 2-CH 2COO) 16(H 2O) 8] 15+ has been synthesized and characterized. In addition, due to the presence of rare earth ions, these ionic liquids show a response to magnetic fields with the highest effective magnetic moment observed so far for an ionic liquid and are rare examples of ionicmore » liquids showing luminescence in the near-infrared. As a result, these ionic liquids also were successfully employed in a three-component synthesis of 2-pyrrolo-3'-yloxindole with an extremely low (<0.035 mol%) catalyst loading rate.« less

Ionic liquids: differential scanning calorimetry as a new indirect method for determination of vaporization enthalpies.

PubMed

Verevkin, Sergey P; Emel'yanenko, Vladimir N; Zaitsau, Dzmitry H; Ralys, Ricardas V; Schick, Christoph

2012-04-12

Differential scanning calorimetry (DSC) has been used to measure enthalpies of synthesis reactions of the 1-alkyl-3-methylimidazolium bromide [C(n)mim][Br] ionic liquids from 1-methylimidazole and n-alkyl bromides (with n = 4, 5, 6, 7, and 8). The optimal experimental conditions have been elaborated. Enthalpies of formation of these ionic liquids in the liquid state have been determined using the DSC results according to the Hess Law. The ideal-gas enthalpies of formation of [C(n)mim][Br] were calculated using the methods of quantum chemistry. They were used together with the DSC results to derive indirectly the enthalpies of vaporization of the ionic liquids under study. In order to validate the indirect determination, the experimental vaporization enthalpy of [C(4)mim][Br] was measured by using a quartz crystal microbalance (QCM). The combination of reaction enthalpy measurements by DSC with modern high-level first-principles calculations opens valuable indirect thermochemical options to obtain values of vaporization enthalpies of ionic liquids.

An electroactive conducting polymer actuator based on NBR/RTIL solid polymer electrolyte

NASA Astrophysics Data System (ADS)

Cho, M. S.; Seo, H. J.; Nam, J. D.; Choi, H. R.; Koo, J. C.; Lee, Y.

2007-04-01

This paper reports the fabrication of a dry-type conducting polymer actuator using nitrile rubber (NBR) as the base material in a solid polymer electrolyte. The conducting polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), was synthesized on the surface of the NBR layer by using a chemical oxidation polymerization technique. Room-temperature ionic liquids (RTIL) based on imidazolium salts, e.g. 1-butyl-3-methyl imidazolium X (where X = BF4-, PF6-, (CF3SO2)2N-), were absorbed into the composite film. The compatibility between the ionic liquids and the NBR polymer was confirmed by DMA. The effect of the anion size of the ionic liquids on the displacement of the actuator was examined. The displacement increased with increasing anion size of the ionic liquids. The cyclic voltammetry responses and the redox switching dynamics of the actuators were examined in different ionic liquids.

Evaluation of ionic liquid stationary phases for one dimensional gas chromatography-mass spectrometry and comprehensive two dimensional gas chromatographic analyses of fatty acids in marine biota.

PubMed

Gu, Qun; David, Frank; Lynen, Frédéric; Vanormelingen, Pieter; Vyverman, Wim; Rumpel, Klaus; Xu, Guowang; Sandra, Pat

2011-05-20

Ionic liquid stationary phases were tested for one dimensional gas chromatography-mass spectrometry (GC-MS) and comprehensive two dimensional gas chromatography (GC×GC) of fatty acid methyl esters from algae. In comparison with polyethylene glycol and cyanopropyl substituted polar stationary phases, ionic liquid stationary phases SLB-IL 82 and SLB-IL 100 showed comparable resolution, but lower column bleeding with MS detection, resulting in better sensitivity. The selectivity and polarity of the ionic liquid phases are similar to a highly polar biscyanopropyl-silicone phase (e.g. HP-88). In GC×GC, using an apolar polydimethyl siloxane×polar ionic liquid column combination, an excellent group-type separation of fatty acids with different carbon numbers and number of unsaturations was obtained, providing information that is complementary to GC-MS identification. Copyright © 2011 Elsevier B.V. All rights reserved.

Recent advances in the applications of ionic liquids in protein stability and activity: a review.

PubMed

Patel, Rajan; Kumari, Meena; Khan, Abbul Bashar

2014-04-01

Room temperatures ionic liquids are considered as miraculous solvents for biological system. Due to their inimitable properties and large variety of applications, they have been widely used in enzyme catalysis and protein stability and separation. The related information present in the current review is helpful to the researchers working in the field of biotechnology and biochemistry to design or choose an ionic liquid that can serve as a noble and selective solvent for any particular enzymatic reaction, protein preservation and other protein based applications. We have extensively analyzed the methods used for studying the protein-IL interaction which is useful in providing information about structural and conformational dynamics of protein. This can be helpful to develop and understanding about the effect of ionic liquids on stability and activity of proteins. In addition, the affect of physico-chemical properties of ionic liquids, viz. hydrogen bond capacity and hydrophobicity on protein stability are discussed.

Self‐Regulative Nanogelator Solid Electrolyte: A New Option to Improve the Safety of Lithium Battery

PubMed Central

Wu, Feng; Chen, Nan; Zhu, Qizhen; Tan, Guoqiang; Li, Li

2016-01-01

The lack of suitable nonflammable electrolytes has delayed battery application in electric vehicles. A new approach to improve the safety performance for lithium battery is proposed here. This technology is based on a nanogelator‐based solid electrolyte made of porous oxides and an ionic liquid. The electrolyte is fabricated using an in situ method and the porous oxides serve as a nonflammable “nanogelator” that spontaneously immobilizes the ionic liquid. The electrolyte exhibits a high liquid‐like apparent ionic conductivity of 2.93 × 10−3 S cm−1 at room temperature. The results show that the nanogelator, which possess self‐regulating ability, is able to immobilize imidazolium‐, pyrrolidinium‐, or piperidinium‐based ionic liquids, simply by adjusting the ion transport channels. Our prototype batteries made of Ti‐nanogeltor solid electrolyte outperform conventional lithium batteries made using ionic liquid and commercial organic liquid electrolytes. PMID:27774385

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

NASA Technical Reports Server (NTRS)

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

2007-01-01

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

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

NASA Astrophysics Data System (ADS)

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

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 and promising results have been obtained. Also, electrodes were formulated using water soluble binders. Using these innovative components, lithium-ion and lithium-metal battery prototypes (0.7-0.8 Ah) have been assembled and cycled between 100% and 0% SOC. The results of these tests showed that such ionic liquids-based prototypes are able to display high capacity, high coulombic efficiency and high cycle life. Moreover, safety tests showed that the introduction of these alternative electrolytes positively contribute to the safety of the batteries.

Beneficial effect of added water on sodium metal cycling in super concentrated ionic liquid sodium electrolytes

NASA Astrophysics Data System (ADS)

Basile, Andrew; Ferdousi, Shammi A.; Makhlooghiazad, Faezeh; Yunis, Ruhamah; Hilder, Matthias; Forsyth, Maria; Howlett, Patrick C.

2018-03-01

The plating and stripping performance of sodium metal in an ionic liquid electrolyte is improved when including water as an additive. Herein we report for the first time the trend of improved cycling behavior of Na0/+ in N-methyl-N-propylpyrrolidinium bis(fluorosulfonyl)imide with 500 ppm H2O. The addition of water to this ionic liquid electrolyte promotes the breakdown of the [FSI]- anion towards beneficial SEI formation. The benefits during plating and stripping of sodium is observed as lower total polarization during symmetrical cell cycling and decreased electrode/electrolyte interface impedance. Sodium metal surfaces after cycling with 500 ppm H2O are shown to be smooth in morphology in comparison to lower additive concentrations. The outcome of adventitious moisture benefiting Na0/+ cycling in an ionic liquid, contrary to conventional electrolytes, allows flexibility in ionic liquid electrolyte design to the benefit of battery manufacturers.

Surface polymerization of (3,4-ethylenedioxythiophene) probed by in situ scanning tunneling microscopy on Au(111) in ionic liquids.

PubMed

Ahmad, Shahzada; Carstens, Timo; Berger, Rüdiger; Butt, Hans-Jürgen; Endres, Frank

2011-01-01

The electropolymerization of 3,4-ethylenedioxythiophene (EDOT) to poly(3,4-ethylenedioxythiophene) (PEDOT) was investigated in the air and water-stable ionic liquids 1-hexyl-3-methylimidazolium tris(pentafluoroethyl) trifluorophosphate [HMIm]FAP and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) amide [EMIm]TFSA. In situ scanning tunnelling microscopy (STM) results show that the electropolymerization of EDOT in the ionic liquid can be probed on the nanoscale. In contrast to present understanding, it was observed that the EDOT can be oxidised in ionic liquids well below its oxidation potential and the under potential growth of polymer was visualized by in situ STM. These results serve as the first study to confirm the under potential growth of conducting polymers in ionic liquids. Furthermore, ex situ microscopy measurements were performed. Quite a high current of 670 nA was observed on the nanoscale by conductive scanning force microscopy (CSFM).

Robust and versatile ionic liquid microarrays achieved by microcontact printing

NASA Astrophysics Data System (ADS)

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

2014-04-01

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.

Impurity effects on ionic-liquid-based supercapacitors

DOE PAGES

Liu, Kun; Lian, Cheng; Henderson, Douglas; ...

2016-12-27

Small amounts of an impurity may affect the key properties of an ionic liquid and such effects can be dramatically amplified when the electrolyte is under confinement. Here the classical density functional theory is employed to investigate the impurity effects on the microscopic structure and the performance of ionic-liquid-based electrical double-layer capacitors, also known as supercapacitors. Using a primitive model for ionic species, we study the effects of an impurity on the double layer structure and the integral capacitance of a room temperature ionic liquid in model electrode pores and find that an impurity strongly binding to the surface ofmore » a porous electrode can significantly alter the electric double layer structure and dampen the oscillatory dependence of the capacitance with the pore size of the electrode. Meanwhile, a strong affinity of the impurity with the ionic species affects the dependence of the integral capacitance on the pore size. Up to 30% increase in the integral capacitance can be achieved even at a very low impurity bulk concentration. As a result, by comparing with an ionic liquid mixture containing modified ionic species, we find that the cooperative effect of the bounded impurities is mainly responsible for the significant enhancement of the supercapacitor performance.« less

Ionic-liquid-impregnated resin for the microwave-assisted solid-liquid extraction of triazine herbicides in honey.

PubMed

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

2015-09-01

Microwave-assisted ionic-liquid-impregnated resin solid-liquid extraction was developed for the extraction of triazine herbicides, including cyanazine, metribuzin, desmetryn, secbumeton, terbumeton, terbuthylazine, dimethametryn, and dipropetryn in honey samples. The ionic-liquid-impregnated resin was prepared by immobilizing 1-hexyl-3-methylimidazolium hexafluorophosphate in the microspores of resin. The resin was used as the extraction adsorbent. The extraction and enrichment of analytes were performed in a single step. The extraction time can be shortened greatly with the help of microwave. The effects of experimental parameters including type of resin, type of ionic liquid, mass ratio of resin to ionic liquid, extraction time, amount of the impregnated resin, extraction temperature, salt concentration, and desorption conditions on the extraction efficiency, were investigated. A Box-Behnken design was applied to the selection of the experimental parameters. The recoveries were in the range of 80.1 to 103.4% and the relative standard deviations were lower than 6.8%. The present method was applied to the analysis of honey samples. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis and characterization of novel chiral ionic liquids and investigation of their enantiomeric recognition properties.

PubMed

Bwambok, David K; Marwani, Hadi M; Fernand, Vivian E; Fakayode, Sayo O; Lowry, Mark; Negulescu, Ioan; Strongin, Robert M; Warner, Isiah M

2008-02-01

We report the synthesis and characterization of amino acid ester based chiral ionic liquids, derived from L- and D-alanine tert butyl ester chloride. The synthesis was accomplished via an anion metathesis reaction between commercially available L- and D-alanine tert butyl ester chloride using a variety of counterions such as lithium bis (trifluoromethane) sulfonimide, silver nitrate, silver lactate, and silver tetrafluoroborate. Both enantiomeric forms were obtained as confirmed by bands of opposite sign in the circular dichroism spectra. The L- and D-alanine tert butyl ester bis (trifluoromethane) sulfonimide were obtained as liquids at room temperature and intriguingly exhibited the highest thermal stability (up to 263 degrees C). In addition, the ionic liquids demonstrated enantiomeric recognition ability as evidenced by splitting of racemic Mosher's sodium salt signal using a liquid state (19)F nuclear magnetic resonance (NMR) and fluorescence spectroscopy. The L- and D-alanine tert butyl ester chloride resulted in solid salts with nitrate, lactate, and tetrafluoroborate anions. This illustrates the previously observed tunability of ionic liquid synthesis, resulting in ionic liquids of varying properties as a function of varying the anion.

Ionic Liquid Catalyzed Electrolyte for Electrochemical Polyaniline Supercapacitors

NASA Astrophysics Data System (ADS)

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

2013-05-01

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.

Molecular dynamics simulation of the ionic liquid N-ethyl-N,N-dimethyl-N-(2-methoxyethyl)ammonium bis(trifluoromethanesulfonyl)imide.

PubMed

Siqueira, Leonardo J A; Ribeiro, Mauro C C

2007-10-11

Thermodynamics, structure, and dynamics of an ionic liquid based on a quaternary ammonium salt with ether side chain, namely, N-ethyl-N,N-dimethyl-N-(2-methoxyethyl)ammonium bis(trifluoromethanesulfonyl)imide, MOENM2E TFSI, are investigated by molecular dynamics (MD) simulations. Average density and configurational energy of simulated MOENM2E TFSI are interpreted with models that take into account empirical ionic volumes. A throughout comparison of the equilibrium structure of MOENM2E TFSI with previous results for the more common ionic liquids based on imidazolium cations is provided. Several time correlation functions are used to reveal the microscopic dynamics of MOENM2E TFSI. Structural relaxation is discussed by the calculation of simultaneous space-time correlation functions. Temperature effects on transport coefficients (diffusion, conductivity, and viscosity) are investigated. The ratio between the actual conductivity and the estimate from ionic diffusion by the Nernst-Einstein equation indicates that correlated motion of neighboring ions in MOENM2E TFSI is similar to imidazolium ionic liquids. In line with experiment, Walden plot of conductivity and viscosity indicates that simulated MOENM2E TFSI should be classified as a poor ionic liquid.

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

PubMed

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

2009-08-01

Ionic liquids are studied intensively for different applications. They tend to be denoted as "green solvents", largely because of their low vapour pressure. In recent years toxicity and biotoxicity of ionic liquids have also been investigated, which proved that not all of these are "green". In this paper the use of ionic liquids based on choline chloride and ethylene glycol in electrochemistry is discussed in the context of their use as green solvents. Due to their low toxicity and ready biodegradability, these deep eutectic solvents are promising for the electrodeposition of metals. The influence of the use of these liquids as metal deposition baths on the waste water is investigated. Drag-out was found to be the most influencing parameter on the environmental impact of the process, as it is three times higher compared to classical solutions due to the higher viscosity of the ionic liquid. There are no major changes needed in the rinsing configuration of classic electroplating plants, and ion exchange to remove the metal out of the waste water was not hindered by the presence of the ionic liquid. The formation of by-products during the deposition of metals has to be further investigated and evaluated in consideration of the environmental impact.

Fundamental Insights into the Dissolution and Precipitation of Cellulosic Biomass from Ionic Liquid Mixtures

NASA Astrophysics Data System (ADS)

Minnick, David L.

Lignocellulose is the most abundant biopolymer on earth making it a promising feedstock for the production of renewable chemicals and fuels. However, utilization of biomass remains a challenge as recalcitrance of cellulose and hemicellulose hinder separation and conversion of these carbohydrates. For instance, the complex inter- and intra- molecular hydrogen bonding network of cellulose renders it insoluble in nearly all aqueous and organic solvents. Alternatively, select ionic liquids (ILs) dissolve significant quantities. Through an ionic liquid mediated dissolution and precipitation process cellulose crystallinity is significantly reduced consequently enhancing subsequent chemical and biochemical reaction processes. Therefore, understanding the thermodynamics of ionic liquid - cellulose mixtures is imperative to developing an IL based biomass processing system. This dissertation illustrates solid-liquid phase equilibrium results for the dissolution and precipitation of cellulose in various IL/cosolvent, IL/antisolvent, and IL/mixed solvent systems with the ionic liquid 1-ethyl-3-methylimidazolium diethyl phosphate ([EMIm][DEP]). Molecular interactions between the ionic liquid, organic solvents, and cellulose are assessed by spectroscopic techniques including Kamlet-Taft solvatochromic analysis, FTIR, and NMR. Additionally, this dissertation discusses how preferential solvation of the IL cation and anion by co- and anti-solvents impact the ability of IL ions to interact with cellulose thus affecting the cellulose dissolution capacity of the various IL-solvent mixtures.

Electrical double layer modulation of hybrid room temperature ionic liquid/aqueous buffer interface for enhanced sweat based biosensing.

PubMed

Jagannath, Badrinath; Muthukumar, Sriram; Prasad, Shalini

2018-08-03

We have investigated the role of kosmotropic anionic moieties and chaotropic cationic moieties of room temperature hydrophilic ionic liquids in enhancing the biosensing performance of affinity based immunochemical biosensors in human sweat. Two ionic liquids, 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM[BF 4 ]) and choline dihydrogen phosphate (Choline[DHP]) were investigated in this study with Choline[DHP] being more kosmotropic in nature having a more protein stabilizing effect based on the hofmeister series. Non-faradaic interfacial charge transfer has been employed as the mechanism for evaluating the formation and the biosensing of capture probe antibodies in room temperature ionic liquids (RTILs)/aqueous human sweat interface. The charge of the ionic moieties were utilized to form compact electrical double layers around the antibodies for enhancing the stability of the antibody capture probes, which was evaluated through zeta potential measurements. The zeta potential measurements indicated stability of antibodies due to electrostatic repulsion of the RTIL charged moieties encompassing the antibodies, thus preventing any aggregation. Here, we report for the first time of non-faradaic electrochemical impedance spectroscopy equivalent circuit model analysis for analyzing and interpreting affinity based biosensing at hybrid electrode/ionic liquid-aqueous sweat buffer interface guided by the choice of the ionic liquid. Interleukin-6 (IL-6) and cortisol two commonly occurring biomarkers in human sweat were evaluated using this method. The limit of detection (LOD) obtained using both ionic liquids for IL-6 was 0.2 pg mL -1 with cross-reactivity studies indicating better performance of IL-6 detection using Choline[DHP] and no response to cross-reactive molecule. The LOD of 0.1 ng/mL was achieved for cortisol and the cross-reactivity studies indicated that cortisol antibody in BMIM[BF 4 ] did not show any signal response to cross-reactive molecules. Furthermore, improved sensitivity and LOD was achieved using ionic liquids as compared to capture probes in aqueous buffer. Copyright © 2018 Elsevier B.V. All rights reserved.

Failure Mechanisms of Hollow Fiber Supported Ionic Liquid Membranes

PubMed Central

Zeh, Matthew; Wickramanayake, Shan; Hopkinson, David

2016-01-01

Hollow fiber supported ionic liquid membranes (SILMs) were tested using the bubble point method to investigate potential failure modes, including the maximum transmembrane pressure before loss of the ionic liquid from the support. Porous hollow fiber supports were fabricated with different pore morphologies using Matrimid® and Torlon® as the polymeric material and 1-hexyl-3-methylimidalzolium bis(trifluoromethylsulfonyl)imide ([C6mim][Tf2N]) as the ionic liquid (IL) component. Hollow fiber SILMs were tested for their maximum pressure before failure, with pressure applied either from the bore side or shell side. It was found that the membranes exhibited one or more of three different modes of failure when pressurized: liquid loss (occurring at the bubble point), rupture, and collapse. PMID:27023620

Synthesis of (3-Methoxycarbonyl)coumarin in an Ionic Liquid: An Advanced Undergraduate Project for Green Chemistry

ERIC Educational Resources Information Center

Verdía, Pedro; Santamarta, Francisco; Tojo, Emilia

2017-01-01

An experiment for an undergraduate organic chemistry class based on the application of an ionic liquid as solvent and catalyst of an organic reaction is reported. The whole experiment requires three 3-h lab sessions. First, students prepare the ionic liquid dimethylimidazolium methylsulfate, which is then used as a recyclable catalyst/reaction…

f-Elements in ionic liquids: A synthetic, spectroscopic and electrochemical study

NASA Astrophysics Data System (ADS)

Bhatt, Anand Indravadan

This thesis reports on chemical research directed towards the utilisation of low temperature ionic liquids (LTILs) for the electrorefming of uranium and plutonium from spent nuclear fuel. Initial studies focus on evaluating the relevant physical and electrochemical properties of LTILs. One room temperature ionic liquid, [(CH[3])[3]N(n-C[4]H[9])][N(SO[2]CF[3])[2

An elegant access to formation and vaporization enthalpies of ionic liquids by indirect DSC experiment and "in silico" calculations.

PubMed

Verevkin, Sergey P; Zaitsau, Dzmitry H; Emel'yanenko, Vladimir N; Schick, Christoph; Jayaraman, Saivenkataraman; Maginn, Edward J

2012-07-14

We used DSC for determination of the reaction enthalpy of the synthesis of the ionic liquid [C(4)mim][Cl]. A combination of DSC and quantum chemical calculations presents a new, indirect way to study thermodynamics of ionic liquids. The new procedure was validated with two direct experimental measurements and MD simulations.

The Solubility Parameters of Ionic Liquids

PubMed Central

Marciniak, Andrzej

2010-01-01

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

Enzyme activity in dialkyl phosphate ionic liquids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomas, M.F.; Dunn, J.; Li, L.-L.

2011-12-01

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

Asymmetric Michael Addition Mediated by Chiral Ionic Liquids.

PubMed

Suzuki, Yumiko

2018-06-01

Chiral ionic liquids with a focus on their applications in asymmetric Michael additions and related reactions were reviewed. The examples were classified on the basis of the mode of asymmetric induction (e.g., external induction/non-covalent interaction or internal induction/covalent bond formation), the roles in reactions (as a solvent or catalyst), and their structural features (e.g., imidazolium-based chiral cations, other chiral oniums; proline derivatives). Most of the reactions with high chiral induction are Michael addition of ketones or aldehydes to chalcones or nitrostyrenes where proline-derived chiral ionic liquids catalyze the reaction through enamine/ iminium formation. Many reports demonstrate the recyclability of ionic liquid-tagged pyrrolidines.

Block copolymers from ionic liquids for the preparation of thin carbonaceous shells

PubMed Central

Hanif, Sadaf; Oschmann, Bernd; Spetter, Dmitri; Tahir, Muhammad Nawaz; Tremel, Wolfgang

2017-01-01

This paper describes the controlled radical polymerization of an ionic-liquid monomer by RAFT polymerization. This allows the control over the molecular weight of ionic liquid blocks in the range of 8000 and 22000 and of the block-copolymer synthesis. In this work we focus on block copolymers with an anchor block. They can be used to control the formation of TiO2 nanoparticles, which are functionalized thereafter with a block of ionic-liquid polymer. Pyrolysis of these polymer functionalized inorganic nanoparticles leads to TiO2 nanoparticles coated with a thin carbonaceous shell. Such materials may, e.g., be interesting as battery materials. PMID:28904612

Block copolymers from ionic liquids for the preparation of thin carbonaceous shells.

PubMed

Hanif, Sadaf; Oschmann, Bernd; Spetter, Dmitri; Tahir, Muhammad Nawaz; Tremel, Wolfgang; Zentel, Rudolf

2017-01-01

This paper describes the controlled radical polymerization of an ionic-liquid monomer by RAFT polymerization. This allows the control over the molecular weight of ionic liquid blocks in the range of 8000 and 22000 and of the block-copolymer synthesis. In this work we focus on block copolymers with an anchor block. They can be used to control the formation of TiO 2 nanoparticles, which are functionalized thereafter with a block of ionic-liquid polymer. Pyrolysis of these polymer functionalized inorganic nanoparticles leads to TiO 2 nanoparticles coated with a thin carbonaceous shell. Such materials may, e.g., be interesting as battery materials.

Structure-Antibacterial Activity Relationships of Imidazolium-Type Ionic Liquid Monomers, Poly(ionic liquids) and Poly(ionic liquid) Membranes: Effect of Alkyl Chain Length and Cations.

PubMed

Zheng, Zhiqiang; Xu, Qiming; Guo, Jiangna; Qin, Jing; Mao, Hailei; Wang, Bin; Yan, Feng

2016-05-25

The structure-antibacterial activity relationship between the small molecular compounds and polymers are still elusive. Here, imidazolium-type ionic liquid (IL) monomers and their corresponding poly(ionic liquids) (PILs) and poly(ionic liquid) membranes were synthesized. The effect of chemical structure, including carbon chain length of substitution at the N3 position and charge density of cations (mono- or bis-imidazolium) on the antimicrobial activities against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was investigated by determination of minimum inhibitory concentration (MIC). The antibacterial activities of both ILs and PILs were improved with the increase of the alkyl chain length and higher charge density (bis-cations) of imidazolium cations. Moreover, PILs exhibited lower MIC values relative to the IL monomers. However, the antibacterial activities of PIL membranes showed no correlation to those of their analogous small molecule IL monomers and PILs, which increased with the charge density (bis-cations) while decreasing with the increase of alkyl chain length. The results indicated that antibacterial property studies on small molecules and homopolymers may not provide a solid basis for evaluating that in corresponding polymer membranes.

Static and transport properties of alkyltrimethylammonium cation-based room-temperature ionic liquids.

PubMed

Seki, Shiro; Tsuzuki, Seiji; Hayamizu, Kikuko; Serizawa, Nobuyuki; Ono, Shimpei; Takei, Katsuhito; Doi, Hiroyuki; Umebayashi, Yasuhiro

2014-05-01

We have measured physicochemical properties of five alkyltrimethylammonium cation-based room-temperature ionic liquids and compared them with those obtained from computational methods. We have found that static properties (density and refractive index) and transport properties (ionic conductivity, self-diffusion coefficient, and viscosity) of these ionic liquids show close relations with the length of the alkyl chain. In particular, static properties obtained by experimental methods exhibit a trend complementary to that by computational methods (refractive index ∝ [polarizability/molar volume]). Moreover, the self-diffusion coefficient obtained by molecular dynamics (MD) simulation was consistent with the data obtained by the pulsed-gradient spin-echo nuclear magnetic resonance technique, which suggests that computational methods can be supplemental tools to predict physicochemical properties of room-temperature ionic liquids.

Effect of Brönsted acidic ionic liquid 1-(1-propylsulfonic)-3-methylimidazolium chloride on growth and co-fermentation of glucose, xylose and arabinose by Zymomonas mobilis AX101.

PubMed

Gyamerah, M; Ampaw-Asiedu, M; Mackey, J; Menezes, B; Woldesenbet, S

2018-06-01

The potential of large-scale lignocellulosic biomass hydrolysis to fermentable sugars using ionic liquids has increased interest in this green chemistry route to fermentation for fuel-ethanol production. The ionic liquid 1-(1-propylsulfonic)-3-methylimidazolium chloride compared to other reported ionic liquids has the advantage of hydrolysing lignocellulosic biomass to reducing sugars at catalytic concentrations (≤0·032 mol l -1 ) in a single step. However, effects of this ionic liquid on co-fermentation of glucose, xylose and arabinose to ethanol by recombinant Zymomonas mobilisAX101 has not been studied. Authentic glucose, xylose and arabinose were used to formulate fermentation media at varying catalytic 1-(1-propylsulfonic)-3-methylimidazolium chloride concentrations for batch co-fermentation of the sugars using Z. mobilisAX101. The results showed that at 0·008, 0·016 and 0·032 mol l -1 ionic liquid in the culture medium, cell growth decreased by 10, 27 and 67% respectively compared to the control. Ethanol yields were 62·6, 61·8, 50·5 and 23·1% for the control, 0·008, 0·016 and 0·032 mol l -1 ionic liquid respectively. The results indicate that lignocellulosic biomass hydrolysed using 0·008 mol l -1 of 1-(1-propylsulfonic)-3-methylimidazolium chloride would eliminate an additional separation step and provide a ready to use fermentation substrate. This is the first reported study of the effect of the Brönsted acidic ionic liquid 1-(1-propylsulfonic)-3-methylimidazolium chloride on growth and co-fermentation of glucose, xylose and arabinose by Zymomonas mobilisAX101 in batch culture. Growth on and co-fermentation of the sugars by Z. mobilisAX 101 with no significant inhibition by the ionic liquid at the same catalytic amounts of 0·008 mol l -1 used to hydrolyse lignocellulosic biomass to reducing sugars overcome two major hurdles that adversely affect the process economics of large-scale industrial cellulosic fuel ethanol production; the energy-intensive hydrolysis and ionic liquid separation steps. © 2018 The Society for Applied Microbiology.

Translational and Rotational Diffusion of Two Differently Charged Solutes in Ethylammonium Nitrate-Methanol Mixture: Does the Nanostructure of the Amphiphiles Influence the Motion of the Solute?

PubMed

Kundu, Niloy; Roy, Arpita; Dutta, Rupam; Sarkar, Nilmoni

2016-06-23

In this Article, we have investigated the translational and rotational diffusion of two structurally similar but differently charged solutes (rhodamine 6G perchlorate and fluorescein sodium salt) in ethylammonium nitrate (EAN)-methanol (CH3OH) mixture to understand the effect of added ionic liquid on the motion of the solutes. EAN and CH3OH both are amphiphilic molecules and characterized by an extended hydrogen bonding network. Recently, Russina et al. found that a wide distribution of clusters exist in the CH3OH rich region (0.10 ≤ χEAN ≤ 0.15) and EAN molecules preserve their bulk-sponge-like morphology (Russina, O.; Sferrazza, A.; Caminiti, R.; Triolo, A. J. Phys. Chem. Lett. 2014, 5, 1738-1742). The effect of this microheterogeneous mixture on the solute's motion shows some interesting results compared to other PIL (protic ionic liquid)-cosolvent mixtures. Analysis of the time-resolved anisotropy data with the aid of Stokes-Einstein-Debye (SED) hydrodynamic theory predicts that the reorientation time of both of the solutes appears close to the stick hydrodynamic line in the methanol rich region. The hydrogen bond accepting solutes experience specific interaction with CH3OH, and with increasing concentration of EAN, the specific interaction between the solute and solvent molecules is decreased while the decrease is more prominent in the low mole fraction of EAN due to the large size of cluster formation. The temperature dependent anisotropy measurements show that the hydrogen bonding interaction between EAN and CH3OH is increased with increasing temperature. Moreover, fluorescence correlation spectroscopy (FCS) shows the dynamic heterogeneity of the mixture which is due to the segregation of the alkyl chain of the PIL. Formation of a large cluster at a low mole fraction of IL (0.10 ≤ χEAN ≤ 0.15) can be proved by the insensitivity of the translational diffusion and rotational activation energy of the solutes to the concentration of EAN. Thus, the result of the work suggests that the addition of EAN to the CH3OH affects the specific interaction between solute and solvent and, as a consequence, the translational motion as well as the rotational motion of the solutes are modulated.

Comparison of the effect of ionic liquids containing hexafluorophosphate and trifluoroacetate anions on the inhibition of growth and oxidative stress in spring barley and common radish.

PubMed

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

2017-08-01

Ionic liquids are a group of chemical compounds with chemical properties that are of great interest to various fields of science and industry. However, commercial use of these substances raises concern because they may threaten the natural ecosystems. The present study used 2 types of (-)-menthol-containing imidazolium chiral ionic liquids: 1-[(1R,2S,5R)-(-)-menthoxymethyl]-3-methylimidazolium hexafluorophosphate [Im-Men][PF 6 ] and 1-[(1R,2S,5R)-(-)-menthoxymethyl]-3-methylimidazolium trifluoroacetate [Im-Men][CF 3 CO 2 ]. The effects of these compounds on growth and development of spring barley (Hordeum vulgare) and common radish (Raphanus sativus L. subvar. radicula Pers.) were investigated. The present study demonstrated that chiral ionic liquids produced a relatively high phytotoxicity, by shortening the plants' lengths and roots, thus causing a decline in the experimental plants' fresh weights. The investigated ionic liquids also led to a reduction in photosynthetic pigment levels, changes in hydrogen peroxide and malondialdehyde content, and changes in the activities of superoxide dismutase, catalase, and peroxidase in both plants. Changes in these enzymes were used to indicate oxidative stress levels in spring barley and common radish. It was demonstrated that imidazolium ionic liquid-induced phytotoxicity depended largely on the type of anion. The liquid [Im-Men][PF 6 ] exhibited higher toxicity toward spring barley and common radish seedlings. Common radish was more resistant to chiral ionic liquids. Environ Toxicol Chem 2017;36:2167-2177. © 2017 SETAC. © 2017 SETAC.

Small angle neutron scattering from 1-alkyl-3-methylimidazolium hexafluorophosphate ionic liquids ([Cnmim][PF6], n=4, 6, and 8)

NASA Astrophysics Data System (ADS)

Hardacre, Christopher; Holbrey, John D.; Mullan, Claire L.; Youngs, Tristan G. A.; Bowron, Daniel T.

2010-08-01

The presence of local anisotropy in the bulk, isotropic, and ionic liquid phases—leading to local mesoscopic inhomogeneity—with nanoscale segregation and expanding nonpolar domains on increasing the length of the cation alkyl-substituents has been proposed on the basis of molecular dynamics (MD) simulations. However, there has been little conclusive experimental evidence for the existence of intermediate mesoscopic structure between the first/second shell correlations shown by neutron scattering on short chain length based materials and the mesophase structure of the long chain length ionic liquid crystals. Herein, small angle neutron scattering measurements have been performed on selectively H/D-isotopically substituted 1-alkyl-3-methylimidazolium hexafluorophosphate ionic liquids with butyl, hexyl, and octyl substituents. The data show the unambiguous existence of a diffraction peak in the low-Q region for all three liquids which moves to longer distances (lower Q), sharpens, and increases in intensity with increasing length of the alkyl substituent. It is notable, however, that this peak occurs at lower values of Q (longer length scale) than predicted in any of the previously published MD simulations of ionic liquids, and that the magnitude of the scattering from this peak is comparable with that from the remainder of the amorphous ionic liquid. This strongly suggests that the peak arises from the second coordination shells of the ions along the vector of alkyl-chain substituents as a consequence of increasing the anisotropy of the cation, and that there is little or no long-range correlated nanostructure in these ionic liquids.

Ultrasound-assisted magnetic solid-phase extraction based ionic liquid-coated Fe3O4@graphene for the determination of nitrobenzene compounds in environmental water samples.

PubMed

Cao, Xiaoji; Shen, Lingxiao; Ye, Xuemin; Zhang, Feifei; Chen, Jiaoyu; Mo, Weimin

2014-04-21

An ultrasound-assisted magnetic solid-phase extraction procedure with the [C7MIM][PF6] ionic liquid-coated Fe3O4-grafted graphene nanocomposite as the magnetic adsorbent has been developed for the determination of five nitrobenzene compounds (NBs) in environmental water samples, in combination with high performance liquid chromatography-photodiode array detector (HPLC-PDA). Several significant factors that affect the extraction efficiency, such as the types of magnetic nanoparticle and ionic liquid, the volume of ionic liquid and the amount of magnetic nanoparticles, extraction time, ionic strength, and solution pH, were investigated. With the assistance of ultrasound, adsorbing nitrobenzene compounds by ionic liquid and self-aggregating ionic liquid onto the surface of the Fe3O4-grafted graphene proceeded synchronously, which made the extraction achieved the maximum within 20 min using only 144 μL [C7MIM][PF6] and 3 mg Fe3O4-grafted graphene. Under the optimized conditions, satisfactory linearities were obtained for all NBs with correlation coefficients larger than 0.9990. The mean recoveries at two spiked levels ranged from 80.35 to 102.77%. Attributed to the convenient magnetic separation, the Fe3O4-grafted graphene could be recycled many times. The proposed method was demonstrated to be feasible, simple, solvent-saving and easy to operate for the trace analysis of NBs in environmental water samples.

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

PubMed

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

2014-02-14

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

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

NASA Astrophysics Data System (ADS)

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

2014-02-01

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

Application of a new amidophosphite ligand to Rh-catalyzed asymmetric hydrogenation of β-dehydroamino acid derivatives in supercritical carbon dioxide: activation effect of protic Co-solvents.

PubMed

Lyubimov, Sergey E; Rastorguev, Eugenie A; Davankov, Vadim A

2011-09-01

New chiral amidophosphite ligand was synthesized and tested in the Rh-catalyzed asymmetric hydrogenation of (Z)-β-(acylamino)acrylates in protic solvents and supercritical carbon dioxide (scCO(2) ) The catalytic performance is affected greatly by the acidity of the solvents. Better enantioselectivity (up to 88% ee) was achieved in scCO(2) containing 1,1,1,3,3,3-hexafluoro-2-propanol, compared to neat protic solvents. Copyright © 2011 Wiley-Liss, Inc.

Electrostatic interactions in soft particle systems: mesoscale simulations of ionic liquids.

PubMed

Wang, Yong-Lei; Zhu, You-Liang; Lu, Zhong-Yuan; Laaksonen, Aatto

2018-05-21

Computer simulations provide a unique insight into the microscopic details, molecular interactions and dynamic behavior responsible for many distinct physicochemical properties of ionic liquids. Due to the sluggish and heterogeneous dynamics and the long-ranged nanostructured nature of ionic liquids, coarse-grained meso-scale simulations provide an indispensable complement to detailed first-principles calculations and atomistic simulations allowing studies over extended length and time scales with a modest computational cost. Here, we present extensive coarse-grained simulations on a series of ionic liquids of the 1-alkyl-3-methylimidazolium (alkyl = butyl, heptyl-, and decyl-) family with Cl, [BF4], and [PF6] counterions. Liquid densities, microstructures, translational diffusion coefficients, and re-orientational motion of these model ionic liquid systems have been systematically studied over a wide temperature range. The addition of neutral beads in cationic models leads to a transition of liquid morphologies from dispersed apolar beads in a polar framework to that characterized by bi-continuous sponge-like interpenetrating networks in liquid matrices. Translational diffusion coefficients of both cations and anions decrease upon lengthening of the neutral chains in the cationic models and by enlarging molecular sizes of the anionic groups. Similar features are observed in re-orientational motion and time scales of different cationic models within the studied temperature range. The comparison of the liquid properties of the ionic systems with their neutral counterparts indicates that the distinctive microstructures and dynamical quantities of the model ionic liquid systems are intrinsically related to Coulombic interactions. Finally, we compared the computational efficiencies of three linearly scaling O(N log N) Ewald summation methods, the particle-particle particle-mesh method, the particle-mesh Ewald summation method, and the Ewald summation method based on a non-uniform fast Fourier transform technique, to calculate electrostatic interactions. Coarse-grained simulations were performed using the GALAMOST and the GROMACS packages and hardware efficiently utilizing graphics processing units on a set of extended [1-decyl-3-methylimidazolium][BF4] ionic liquid systems of up to 131 072 ion pairs.

Understanding the effect of side groups in ionic liquids on carbon-capture properties: a combined experimental and theoretical effort

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, Fangyong; Lartey, Michael; Damodaran, Krishnan

2013-01-01

Ionic liquids are an emerging class of materials with applications in a variety of fields. Steady progress has been made in the creation of ionic liquids tailored to specific applications. However, the understanding of the underlying structure–property relationships has been slower to develop. As a step in the effort to alleviate this deficiency, the influence of side groups on ionic liquid properties has been studied through an integrated approach utilizing synthesis, experimental determination of properties, and simulation techniques. To achieve this goal, a classical force field in the framework of OPLS/Amber force fields has been developed to predict ionic liquidmore » properties accurately. Cu(I)-catalyzed click chemistry was employed to synthesize triazolium-based ionic liquids with diverse side groups. Values of densities were predicted within 3% of experimental values, whereas self-diffusion coefficients were underestimated by about an order of magnitude though the trends were in excellent agreement, the activation energy calculated in simulation correlates well with experimental values. The predicted Henry coefficient for CO{sub 2} solubility reproduced the experimentally observed trends. This study highlights the importance of integrating experimental and computational approaches in property prediction and materials development, which is not only useful in the development of ionic liquids for CO{sub 2} capture but has application in many technological fields.« less

Understanding the effect of side groups in ionic liquids on carbon-capture properties: a combined experimental and theoretical effort

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, Fangyong; Lartey, Michael; Damodaran, Krishnan

Ionic liquids are an emerging class of materials with applications in a variety of fields. Steady progress has been made in the creation of ionic liquids tailored to specific applications. However, the understanding of the underlying structure–property relationships has been slower to develop. As a step in the effort to alleviate this deficiency, the influence of side groups on ionic liquid properties has been studied through an integrated approach utilizing synthesis, experimental determination of properties, and simulation techniques. To achieve this goal, a classical force field in the framework of OPLS/Amber force fields has been developed to predict ionic liquidmore » properties accurately. Cu(I)-catalyzed click chemistry was employed to synthesize triazolium-based ionic liquids with diverse side groups. Values of densities were predicted within 3% of experimental values, whereas self-diffusion coefficients were underestimated by about an order of magnitude though the trends were in excellent agreement, the activation energy calculated in simulation correlates well with experimental values. The predicted Henry coefficient for CO{sub 2} solubility reproduced the experimentally observed trends. This study highlights the importance of integrating experimental and computational approaches in property prediction and materials development, which is not only useful in the development of ionic liquids for CO{sub 2} capture but has application in many technological fields.« less

Ion Transport and Structural Properties of Polymeric Electrolytes and Ionic Liquids from Molecular Dynamics Simulations

NASA Astrophysics Data System (ADS)

Borodin, Oleg

2010-03-01

Molecular dynamics simulations are well suited for exploring electrolyte structure and ion transport mechanisms on the nanometer length scale and the nanosecond time scales. In this presentation we will describe how MD simulations assist in answering fundamental questions about the lithium transport mechanisms in polymeric electrolytes and ionic liquids. In particular, in the first part of the presentation the extent of ion aggregation, the structure of ion aggregates and the lithium cation diffusion in binary polymeric electrolytes will be compared with that of single-ion conducting polymers. In the second part of the talk, the lithium transport in polymeric electrolytes will be compared with that of three ionic liquids ( [emim][FSI] doped with LiFSI , [pyr13][FSI] doped with LiFSI, [emim][BF4] doped with LiBF4). The relation between ionic liquid self-diffusion, conductivity and thermodynamic properties will be discussed in details. A number of correlations between heat of vaporization Hvap, cation-anion binding energy (E+/-), molar volume (Vm), self-diffusion coefficient (D) and ionic conductivity for 29 ionic liquids have been investigated using MD simulations. A significant correlation between D and Hvap has been found, while best correlation was found for -log((D Vm)) vs. Hvap+0.28E+/-. A combination of enthalpy of vaporization and a fraction of the cation-anion binding energy was suggested as a measure of the effective cohesive energy for ionic liquids.

Ionic Liquid Epoxy Resin Monomers

NASA Technical Reports Server (NTRS)

Paley, Mark S. (Inventor)

2013-01-01

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

Potential Energy Surfaces and Dynamics of High Energy Species

DTIC Science & Technology

2009-04-13

explored include ionic liquids and a range of high-nitrogen content and nitrogen-oxygen content species. Polyhedral oligomeric silisesquioxanes are...Approved for Public Release 13. SUPPLEMENTARY NOTES 14. ABSTRACT Several papers on ionic liquids have been published or submitted as a result of this...in energetic ionic liquids . These are variously substituted triazolium, tertazolium, and pentazolium cations. The heats of formation of all species

Membrane contactor assisted extraction/reaction process employing ionic liquids

DOEpatents

Lin, Yupo J [Naperville, IL; Snyder, Seth W [Lincolnwood, IL

2012-02-07

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

Layering, melting, and recrystallization of a close-packed micellar crystal under steady and large-amplitude oscillatory shear flows

DOE Office of Scientific and Technical Information (OSTI.GOV)

López-Barrón, Carlos R., E-mail: carlos.r.lopez-barron@exxonmobil.com; Wagner, Norman J.; Porcar, Lionel

2015-05-15

The rheology and three-dimensional microstructure of a concentrated viscoelastic solution of the triblock copolymer poly(ethylene oxide){sub 106}-poly(propylene oxide){sub 68}-poly(ethylene oxide){sub 106} (Pluronic F127) in the protic ionic liquid ethylammonium nitrate are measured by small angle neutron scattering (SANS) under flow in three orthogonal planes. This solution's shear-thinning viscosity is due to the formation of two-dimensional hexagonal close-packed (HCP) sliding layer structure. Shear-melting of the crystalline structure is observed without disruption of the self-assembled micelles, resulting in a change in flow properties. Spatially resolved measurements in the 1–2 plane reveal that both shear-melting and sliding are not uniform across the Couettemore » gap. Melting and recrystallization of the HCP layers occur cyclically during a single large amplitude oscillatory shear (LAOS) cycle, in agreement with the “stick-slip” flow mechanism proposed by Hamley et al. [Phys. Rev. E 58, 7620–7628 (1998)]. Analysis of 3D “structural” Lissajous curves show that the cyclic melting and sliding are direct functions of the strain rate amplitude and show perfect correlation with the cyclic stress response during LAOS. Both viscosity and structural order obey the Delaware–Rutgers rule. Combining rheology with in situ spatiotemporally resolved SANS is demonstrated to elucidate the structural origins of the nonlinear rheology of complex fluids.« less

Ionic Liquids as a Basis Context for Developing High school Chemistry Teaching Materials

NASA Astrophysics Data System (ADS)

Hernani; Mudzakir, A.; Sumarna, O.

2017-02-01

This research aims to produce a map of connectedness highschool chemical content with the context of the modern chemical materials applications based on ionic liquids. The research method is content analysis of journal articles related to the ionic liquid materials and the textbooks of high school chemistry and textbooks of general chemistry at the university. The instrument used is the development format of basic text that connect and combine content and context. The results showed the connectedness between: (1) the context lubricants ionic liquid with the content of ionic bonding, covalent bonding, metal bonding, interaction between the particles of matter, the elements of main group, the elements of transition group, and the classification of macromolecules; (2) the context of fuel cell electrolite with the content of ionic bonding, covalent bonding, metal bonding, interaction between the particles of matter, Volta cell, and electrolysis cell; (3) the contect of nanocellulose with the content of ionic bonding, covalent bonding, metal bonding, interaction between the particles of matter, colloid, carbon compound, and the classification of macromolecules; and (4) the context of artificial muscle system with the content of ionic bond, covalent bond, metal bonding, interaction between the particles of matter, hydrocarbons, electrolytes and non-electrolytes, and the classification of macromolecules. Based on the result of this content analysis, the context of ionic liquid is predicted can be utilized for the enrichment of high school chemistry and has the potential to become teaching material’s context of high school chemistry in the future.

Toxicity prediction of ionic liquids based on Daphnia magna by using density functional theory

NASA Astrophysics Data System (ADS)

Nu’aim, M. N.; Bustam, M. A.

2018-04-01

By using a model called density functional theory, the toxicity of ionic liquids can be predicted and forecast. It is a theory that allowing the researcher to have a substantial tool for computation of the quantum state of atoms, molecules and solids, and molecular dynamics which also known as computer simulation method. It can be done by using structural feature based quantum chemical reactivity descriptor. The identification of ionic liquids and its Log[EC50] data are from literature data that available in Ismail Hossain thesis entitled “Synthesis, Characterization and Quantitative Structure Toxicity Relationship of Imidazolium, Pyridinium and Ammonium Based Ionic Liquids”. Each cation and anion of the ionic liquids were optimized and calculated. The geometry optimization and calculation from the software, produce the value of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). From the value of HOMO and LUMO, the value for other toxicity descriptors were obtained according to their formulas. The toxicity descriptor that involves are electrophilicity index, HOMO, LUMO, energy gap, chemical potential, hardness and electronegativity. The interrelation between the descriptors are being determined by using a multiple linear regression (MLR). From this MLR, all descriptors being analyzed and the descriptors that are significant were chosen. In order to develop the finest model equation for toxicity prediction of ionic liquids, the selected descriptors that are significant were used. The validation of model equation was performed with the Log[EC50] data from the literature and the final model equation was developed. A bigger range of ionic liquids which nearly 108 of ionic liquids can be predicted from this model equation.

Ionic structure in liquids confined by dielectric interfaces

NASA Astrophysics Data System (ADS)

Jing, Yufei; Jadhao, Vikram; Zwanikken, Jos W.; Olvera de la Cruz, Monica

2015-11-01

The behavior of ions in liquids confined between macromolecules determines the outcome of many nanoscale assembly processes in synthetic and biological materials such as colloidal dispersions, emulsions, hydrogels, DNA, cell membranes, and proteins. Theoretically, the macromolecule-liquid boundary is often modeled as a dielectric interface and an important quantity of interest is the ionic structure in a liquid confined between two such interfaces. The knowledge gleaned from the study of ionic structure in such models can be useful in several industrial applications, such as in the design of double-layer supercapacitors for energy storage and in the extraction of metal ions from wastewater. In this article, we compute the ionic structure in a model system of electrolyte confined by two planar dielectric interfaces using molecular dynamics simulations and liquid state theory. We explore the effects of high electrolyte concentrations, multivalent ions, dielectric contrasts, and external electric field on the ionic distributions. We observe the presence of non-monotonic ionic density profiles leading to a layered structure in the fluid which is attributed to the competition between electrostatic and steric (entropic) interactions. We find that thermal forces that arise from symmetry breaking at the interfaces can have a profound effect on the ionic structure and can oftentimes overwhelm the influence of the dielectric discontinuity. The combined effect of ionic correlations and inhomogeneous dielectric permittivity significantly changes the character of the effective interaction between the two interfaces.

A computational study on choline benzoate and choline salicylate ionic liquids in the pure state and after CO2 adsorption.

PubMed

Aparicio, Santiago; Atilhan, Mert

2012-08-02

Choline-based ionic liquids show very adequate environmental, toxicological, and economical profiles for their application in many different technological areas. We report in this work a computational study on the properties of choline benzoate and choline salicylate ionic liquids, as representatives of this family of compounds, in the pure state and after CO(2) adsorption. Quantum chemistry calculations using the density functional theory approach for ionic pairs and ions, CO(2) pairs, were carried out, and the results analyzed using natural bond orbital and atoms in a molecule approaches. Classical molecular dynamics simulations of ionic liquids were done as a function of pressure, temperature, and CO(2) concentration. Microscopic structuring and intermolecular forces are analyzed together with the dynamic behavior of the studied fluids.

Designing an anion-functionalized fluorescent ionic liquid as an efficient and reversible turn-off sensor for detecting SO2.

PubMed

Che, Siying; Dao, Rina; Zhang, Weidong; Lv, Xiaoyu; Li, Haoran; Wang, Congmin

2017-03-30

A novel anion-functionalized fluorescent ionic liquid was designed and prepared, which was capable of capturing sulphur dioxide with high capacity and could also be used as a good colorimetric and fluorescent SO 2 sensor. Compared to conventional fluorescent sensors, this fluorescent ionic liquid did not undergo aggregation-caused quenching or aggregation-induced emission, and the fluorescence was quenched when exposed to SO 2 , and the fluorescence would quench when exposed to SO 2 . The experimental absorption, spectroscopic investigation, and quantum chemical calculations indicated that the quenching of the fluorescence originated from SO 2 physical absorption, not chemical absorption. Furthermore, this fluorescent ionic liquid exhibited high selectivity, good quantification, and excellent reversibility for SO 2 detection, and showed potential for an excellent liquid sensor.

Enzymatic catalysis of formation of Z-aspartame in ionic liquid - An alternative to enzymatic catalysis in organic solvents.

PubMed

Erbeldinger, M; Mesiano, A J; Russell, A J

2000-01-01

We present the first report of enzymatic catalysis in an ionic liquid. The virtually nonexistent vapor pressure makes ionic liquids an exciting new alternative for enzyme-catalyzed syntheses in environmentally friendly environments. Z-aspartame was synthesized in a thermolysin-catalyzed reaction of carbobenzoxy-L-aspartate and L-phenylalanine methyl ester hydrochloride in 1-butyl-3-methylimidazolium hexafluorophosphate (BP6). Ionic liquids such as BP6 are thermally stable and have a remarkable range of temperatures over which they remain liquid (300 degrees C). With an initial rate of 1.2 +/- 0.1 nmol min(-)(1) mg(-)(1), we observed a competitive rate in comparison to that of enzymatic synthesis in organic solvent. Additionally, the enzyme exhibits outstanding stability, which would normally require immobilization.

Asymmetric Michael Addition Mediated by Chiral Ionic Liquids

PubMed Central

Suzuki, Yumiko

2018-01-01

Chiral ionic liquids with a focus on their applications in asymmetric Michael additions and related reactions were reviewed. The examples were classified on the basis of the mode of asymmetric induction (e.g., external induction/non-covalent interaction or internal induction/covalent bond formation), the roles in reactions (as a solvent or catalyst), and their structural features (e.g., imidazolium-based chiral cations, other chiral oniums; proline derivatives). Most of the reactions with high chiral induction are Michael addition of ketones or aldehydes to chalcones or nitrostyrenes where proline-derived chiral ionic liquids catalyze the reaction through enamine/ iminium formation. Many reports demonstrate the recyclability of ionic liquid-tagged pyrrolidines. PMID:29861702

Modeling the structure and thermodynamics of ferrocenium-based ionic liquids.

PubMed

Bernardes, Carlos E S; Mochida, Tomoyuki; Canongia Lopes, José N

2015-04-21

A new force-field for the description of ferrocenium-based ionic liquids is reported. The proposed model was validated by confronting Molecular Dynamics simulations results with available experimental data-enthalpy of fusion, crystalline structure and liquid density-for a series of 1-alkyl-2,3,4,5,6,7,8,9-octamethylferrocenium bis(trifluoromethylsulfonyl)imide ionic liquids, [CnFc][NTf2] (3 ≤ n ≤ 10). The model is able to reproduce the densities and enthalpies of fusion with deviations smaller than 2.6% and 4.8 kJ mol(-1), respectively. The MD simulation trajectories were also used to compute relevant structural information for the different [CnFc][NTf2] ionic liquids. The results show that, unlike other ILs, the alkyl side chains present in the cations are able to interact directly with the ferrocenium core of other ions. Even the ferrocenium charged cores (with relatively mild charge densities) are able to form small contact aggregates. This causes the partial rupture of the polar network and precludes the formation of extended nano-segregated polar-nonpolar domains normally observed in other ionic liquids.

Development of a dispersive liquid-liquid microextraction method using a lighter-than-water ionic liquid for the analysis of polycyclic aromatic hydrocarbons in water.

PubMed

Medina, Giselle S; Reta, Mario

2016-11-01

A dispersive liquid-liquid microextraction method using a lighter-than-water phosphonium-based ionic liquid for the extraction of 16 polycyclic aromatic hydrocarbons from water samples has been developed. The extracted compounds were analyzed by liquid chromatography coupled to fluorescence/diode array detectors. The effects of several experimental parameters on the extraction efficiency, such as type and volume of ionic liquid and disperser solvent, type and concentration of salt in the aqueous phase and extraction time, were investigated and optimized. Three phosphonium-based ionic liquids were assayed, obtaining larger extraction efficiencies when trihexyl-(tetradecyl)phosphonium bromide was used. The optimized methodology requires a few microliters of a lighter-than-water phosphonium-based ionic liquid, which allows an easy separation of the extraction solvent phase. The obtained limits of detection were between 0.02 and 0.56 μg/L, enrichment factors between 109 and 228, recoveries between 60 and 108%, trueness between 0.4 and 9.9% and reproducibility values between 3 and 12% were obtained. These figures of merit combined with the simplicity, rapidity and low cost of the analytical methodology indicate that this is a viable and convenient alternative to the methods reported in the literature. The developed method was used to analyze polycyclic aromatic hydrocarbons in river water samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ionic imbalance induced self-propulsion of liquid metals

PubMed Central

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

2016-01-01

Components with self-propelling abilities are important building blocks of small autonomous systems and the characteristics of liquid metals are capable of fulfilling self-propulsion criteria. To date, there has been no exploration regarding the effect of electrolyte ionic content surrounding a liquid metal for symmetry breaking that generates motion. Here we show the controlled actuation of liquid metal droplets using only the ionic properties of the aqueous electrolyte. We demonstrate that pH or ionic concentration gradients across a liquid metal droplet induce both deformation and surface Marangoni flow. We show that the Lippmann dominated deformation results in maximum velocity for the self-propulsion of liquid metal droplets and illustrate several key applications, which take advantage of such electrolyte-induced motion. With this finding, it is possible to conceive the propulsion of small entities that are constructed and controlled entirely with fluids, progressing towards more advanced soft systems. PMID:27488954

Ionic imbalance induced self-propulsion of liquid metals.

PubMed

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

2016-08-04

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

Ionic imbalance induced self-propulsion of liquid metals

NASA Astrophysics Data System (ADS)

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

2016-08-01

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

Density and refractive index data of binary and ternary mixtures of imidazolium-based ionic liquids, n-hexane and organic compounds involved in the kinetic resolution of rac-2-pentanol.

PubMed

Montalbán, Mercedes G; Collado-González, Mar; Lozano-Pérez, A Abel; Baños, F Guillermo Díaz; Víllora, Gloria

2018-08-01

This data article is related to the subject of the research article "Extraction of Organic Compounds Involved in the Kinetic Resolution of rac-2-Pentanol from n-Hexane by Imidazolium-based Ionic Liquids: Liquid-Liquid Equilibrium" (Montalbán et al., 2018) [1]. It contains experimental data of density and refractive index of binary and ternary mixtures of imidazolium-based ionic liquids, n -hexane and organic compounds involved in the kinetic resolution of rac -2-pentanol ( rac -2-pentanol, vinyl butyrate, rac -2-pentyl butyrate or butyric acid) measured at 303.15 K and 1 atm. These data are presented as calibration curves which help to determine the composition of the ionic liquid-rich phase knowing its density or refractive index.

Partition coefficients of organic compounds between water and imidazolium-, pyridinium-, and phosphonium-based ionic liquids.

PubMed

Padró, Juan M; Pellegrino Vidal, Rocío B; Reta, Mario

2014-12-01

The partition coefficients, P IL/w, of several compounds, some of them of biological and pharmacological interest, between water and room-temperature ionic liquids based on the imidazolium, pyridinium, and phosphonium cations, namely 1-octyl-3-methylimidazolium hexafluorophosphate, N-octylpyridinium tetrafluorophosphate, trihexyl(tetradecyl)phosphonium chloride, trihexyl(tetradecyl)phosphonium bromide, trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)imide, and trihexyl(tetradecyl)phosphonium dicyanamide, were accurately measured. In this way, we extended our database of partition coefficients in room-temperature ionic liquids previously reported. We employed the solvation parameter model with different probe molecules (the training set) to elucidate the chemical interactions involved in the partition process and discussed the most relevant differences among the three types of ionic liquids. The multiparametric equations obtained with the aforementioned model were used to predict the partition coefficients for compounds (the test set) not present in the training set, most being of biological and pharmacological interest. An excellent agreement between calculated and experimental log P IL/w values was obtained. Thus, the obtained equations can be used to predict, a priori, the extraction efficiency for any compound using these ionic liquids as extraction solvents in liquid-liquid extractions.

Using FT-IR Spectroscopy to Measure Charge Organization in Ionic Liquids

PubMed Central

Burba, Christopher M.; Janzen, Jonathan; Butson, Eric D.; Coltrain, Gage L.

2013-01-01

A major goal in the field of ionic liquids is correlating transport property trends with the underlying liquid structure of the compounds, such as the degree of charge organization among the constituent ions. Traditional techniques for experimentally assessing charge organization are specialized and not readily available for routine measurements. This represents a significant roadblock in elucidating these correlations. We use a combination of transmission and polarized-ATR infrared spectroscopy to measure the degree of charge organization for ionic liquids. The technique is illustrated with a family of 1-alkyl-3-methylimidazolium trifluoromethansulfonate ionic liquids at 30°C. As expected, the amount of charge organization decreases as the alkyl side chain is lengthened, highlighting the important role of short-range repulsive interactions in defining quasilattice structure. Inherent limitations of the method are identified and discussed. The quantitative measurements of charge organization are then correlated with trends in the transport properties of the compounds to highlight the relationship between charge and momentum transport and the underlying liquid structure. Most research laboratories possess infrared spectrometers capable of conducting these measurements, thus, the proposed method may represent a cost-effective solution for routinely measuring charge organization in ionic liquids. PMID:23781877

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liang, Min; Khatun, Sufia; Castner, Edward W., E-mail: ecastner@rci.rutgers.edu

2015-03-28

Ionic liquids having a sufficiently amphiphilic cation can dissolve large volume fractions of alkanes, leading to mixtures with intriguing properties on molecular length scales. The trihexyl(tetradecyl)phosphonium cation paired with the bis(trifluoromethylsulfonyl)amide anion provides an ionic liquid that can dissolve large mole fractions of hexane. We present experimental results on mixtures of n-C{sub 6}D{sub 14} with this ionic liquid. High-energy X-ray scattering studies reveal a persistence of the characteristic features of ionic liquid structure even for 80% dilution with n-C{sub 6}D{sub 14}. Nuclear magnetic resonance self-diffusion results reveal decidedly non-hydrodynamic behavior where the self-diffusion of the neutral, non-polar n-C{sub 6}D{sub 14}more » is on average a factor of 21 times faster than for the cation. Exploitation of the unique structural and transport properties of these mixtures may lead to new opportunities for designer solvents for enhanced chemical reactivity and interface science.« less

Capacitance of Nanoporous Carbon-Based Supercapacitors Is a Trade-Off between the Concentration and the Separability of the Ions.

PubMed

Burt, Ryan; Breitsprecher, Konrad; Daffos, Barbara; Taberna, Pierre-Louis; Simon, Patrice; Birkett, Greg; Zhao, X S; Holm, Christian; Salanne, Mathieu

2016-10-06

Nanoporous carbon-based supercapacitors store electricity through adsorption of ions from the electrolyte at the surface of the electrodes. Room temperature ionic liquids, which show the largest ion concentrations among organic liquid electrolytes, should in principle yield larger capacitances. Here, we show by using electrochemical measurements that the capacitance is not significantly affected when switching from a pure ionic liquid to a conventional organic electrolyte using the same ionic species. By performing additional molecular dynamics simulations, we interpret this result as an increasing difficulty of separating ions of opposite charges when they are more concentrated, that is, in the absence of a solvent that screens the Coulombic interactions. The charging mechanism consistently changes with ion concentration, switching from counterion adsorption in the diluted organic electrolyte to ion exchange in the pure ionic liquid. Contrarily to the capacitance, in-pore diffusion coefficients largely depend on the composition, with a noticeable slowing of the dynamics in the pure ionic liquid.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

2012-01-01

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

Triggering the Chemical Instability of an Ionic Liquid under High Pressure.

PubMed

Faria, Luiz F O; Nobrega, Marcelo M; Temperini, Marcia L A; Bini, Roberto; Ribeiro, Mauro C C

2016-09-01

Ionic liquids are an interesting class of materials due to their distinguished properties, allowing their use in an impressive range of applications, from catalysis to hypergolic fuels. However, the reactivity triggered by the application of high pressure can give rise to a new class of materials, which is not achieved under normal conditions. Here, we report on the high-pressure chemical instability of the ionic liquid 1-allyl-3-methylimidazolium dicyanamide, [allylC1im][N(CN)2], probed by both Raman and IR techniques and supported by quantum chemical calculations. Our results show a reaction occurring above 8 GPa, involving the terminal double bond of the allyl group, giving rise to an oligomeric product. The results presented herein contribute to our understanding of the stability of ionic liquids, which is of paramount interest for engineering applications. Moreover, gaining insight into this peculiar kind of reactivity could lead to the development of new or alternative synthetic routes to achieve, for example, poly(ionic liquids).

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

PubMed

Kuchenbuch, Andrea; Giernoth, Ralf

2015-12-01

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

Process intensification of biodiesel production by using microwave and ionic liquids as catalyst

DOE Office of Scientific and Technical Information (OSTI.GOV)

Handayani, Prima Astuti; Chemical Engineering Program, Faculty of Engineering, Semarang State University; Abdullah

The energy crisis pushes the development and intensification of biodiesel production process. Biodiesel is produced by transesterification of vegetable oils or animal fats and conventionally produced by using acid/base catalyst. However, the conventional method requires longer processing time and obtains lower yield of biodiesel. The microwave has been intensively used to accelerate production process and ionic liquids has been introduced as source of catalyst. This paper discusses the overview of the development of biodiesel production through innovation using microwave irradiation and ionic liquids catalyst to increase the yield of biodiesel. The potential microwave to reduce the processing time will bemore » discussed and compared with other energy power, while the ionic liquids as a new generation of catalysts in the chemical industry will be also discussed for its use. The ionic liquids has potential to enhance the economic and environmental aspects because it has a low corrosion effect, can be recycled, and low waste form.« less

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

NASA Astrophysics Data System (ADS)

Mogurampelly, Santosh; Ganesan, Venkat

2017-02-01

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

Determination of trihalomethanes in waters by ionic liquid-based single drop microextraction/gas chromatographic/mass spectrometry.

PubMed

Aguilera-Herrador, Eva; Lucena, Rafael; Cárdenas, Soledad; Valcárcel, Miguel

2008-10-31

A simple, rapid, solventless method for the determination of trihalomethanes (THMs) (chloroform, bromodichloromethane, dibromochloromethane and bromoform) in water samples is presented. The analytes are extracted from the headspace of the aqueous matrix into a 2 microL drop of the ionic liquid 1-octyl-3-methyl-imidazolium hexafluorophosphate working at 30 degrees C for 30 min. The separation and detection of the target compounds is accomplished by gas chromatography/mass spectrometry owing to the use of an interface that efficiently transfers the analytes extracted in the ionic liquid drop to the gas chromatograph while preventing the ionic liquid from entering the column. The detection limits obtained are below the values compelled by the legislation, ranging from 0.5 microg L(-1) for chloroform and bromodichloromethane to 0.9 microg L(-1) for dibromochloromethane. The use of ionic liquid in the extraction procedure avoids the use of organic solvents and leads to relative standard deviations that range from 3.1% to 4.8%.

Crosslinked Polymer Ionic Liquid/Ionic Liquid Blends Prepared by Photopolymerization as Solid-State Electrolytes in Supercapacitors.

PubMed

Wang, Po-Hsin; Wang, Tzong-Liu; Lin, Wen-Churng; Lin, Hung-Yin; Lee, Mei-Hwa; Yang, Chien-Hsin

2018-04-07

A photopolymerization method is used to prepare a mixture of polymer ionic liquid (PIL) and ionic liquid (IL). This mixture is used as a solid-state electrolyte in carbon nanoparticle (CNP)-based symmetric supercapacitors. The solid electrolyte is a binary mixture of a PIL and its corresponding IL. The PIL matrix is a cross-linked polyelectrolyte with an imidazole salt cation coupled with two anions of Br - in PIL-M-(Br) and TFSI - in PIL-M-(TFSI), respectively. The corresponding ionic liquids have imidazolium salt cation coupled with two anions of Br - and TFSI - , respectively. This study investigates the electrochemical characteristics of PILs and their corresponding IL mixtures used as a solid electrolyte in supercapacitors. Results show that a specific capacitance, maximum power density and energy density of 87 and 58 F·g - ¹, 40 and 48 kW·kg - ¹, and 107 and 59.9 Wh·kg - ¹ were achieved in supercapacitors based on (PIL-M-(Br)) and (PIL-M-(TFSI)) solid electrolytes, respectively.

Process intensification of biodiesel production by using microwave and ionic liquids as catalyst

NASA Astrophysics Data System (ADS)

Handayani, Prima Astuti; Abdullah, dan Hadiyanto

2015-12-01

The energy crisis pushes the development and intensification of biodiesel production process. Biodiesel is produced by transesterification of vegetable oils or animal fats and conventionally produced by using acid/base catalyst. However, the conventional method requires longer processing time and obtains lower yield of biodiesel. The microwave has been intensively used to accelerate production process and ionic liquids has been introduced as source of catalyst. This paper discusses the overview of the development of biodiesel production through innovation using microwave irradiation and ionic liquids catalyst to increase the yield of biodiesel. The potential microwave to reduce the processing time will be discussed and compared with other energy power, while the ionic liquids as a new generation of catalysts in the chemical industry will be also discussed for its use. The ionic liquids has potential to enhance the economic and environmental aspects because it has a low corrosion effect, can be recycled, and low waste form.

Effect of Aprotic Solvents on the Dynamics of a Room Temperature Ionic Liquid

NASA Astrophysics Data System (ADS)

Osti, Naresh; van Aken, Katherine; Thompson, Matthew; Tiet, Felix; Jiang, De-En; Cummings, Peter; Gogotsi, Yury; Mamontov, Eugene

Room temperature ionic liquids (RTILs) have attracted much attention as electrolytes in energy storage devices because of their peculiar physical and chemical characteristics. However, their remarkably high viscosity, which results in low conductivity and diffusivity, may adversely affect the charging and discharging rates. Despite changing molecular configurations, use of aprotic solvent allows to enhance the transport properties of ionic liquids by disrupting the cation-anion interactions. We explore the impact of dipole moment of aprotic solvents on the cation-anion interaction and transport in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [BMIM +][Tf2N-], RTIL using molecular dynamics (MD) simulations and quasi-elastic neutrons scattering (QENS) measurements. We observed an increase in cation diffusivity with the increasing dipole moment of the solvent. This effect is due to a decrease in the solvation free energy induced by the increasing solvent polarity. A clear nano-phase separation into ionic liquid-rich and ionic liquid-poor phases as observed by QENS will be also discussed.

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

DOE PAGES

Liang, Min; Khatun, Sufia; Castner, Edward W.

2015-03-28

Ionic liquids having a sufficiently amphiphilic cation can dissolve large volume fractions of alkanes, leading to mixtures with intriguing properties on molecular length scales. The trihexyl(tetradecyl)phosphonium cation paired with the bis(trifluoromethylsulfonyl)amide anion provides an ionic liquid that can dissolve large mole fractions of hexane. We present experimental results on mixtures of n-C 6D 14 with this ionic liquid. High- energy X-ray scattering studies reveal a persistence of the characteristic features of ionic liquid structure even for 80% dilution with n-C 6D 14. NMR self-diffusion results reveal decidedly non-hydrodynamic behavior where the self-diffusion of the neutral, non-polar n-C 6D 14 ismore » on average a factor of 21 times faster than for the cation. Exploitation of the unique structural and transport properties of these mixtures may lead to new opportunities for designer solvents for enhanced chemical reactivity and interface science.« less

Molecular and mesoscopic study of ionic liquids and their use as solvents of active agents released by polymeric vehicles

NASA Astrophysics Data System (ADS)

Ramos-Rodríguez, Daniel-Apolinar; Rodríguez-Hidalgo, María-del-Rosario; Soto-Figueroa, César; Vicente, Luis

2010-03-01

This work explores the diffusivity of the drug albendazole contained in a polymeric vehicle, Styrene-Divinylbenzene (ST-DVD), when it is subject to different environments. The environments consist of water and three different ionic liquids. First, the solubility parameters of these ionic liquids, [BMIM][PF6], [HMIM][Br] and [BMIM][BF4], and albendazole were evaluated by means of molecular dynamics employing COMPASS force-field and a NPT ensemble at 298 K. Then a mesoscopic simulation using Dissipative Particle Dynamics (DPD) was used. In the presence of ionic liquids the albendazole exhibits a diffusivity in [BMIM][PF6] around ten times that shown in [BMIM][BF4] or [HMIM][Br]. This is connected with the corresponding solvent power. The results obtained from these molecular and mesoscopic simulations are consistent with reported experimental results and are useful to predict and evaluate the solvent power of ionic liquids applied to drugs of pharmaceutical use.

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

PubMed

Das, Rudra Narayan; Roy, Kunal

2014-06-01

Hazardous potential of ionic liquids is becoming an issue of high concern with increasing application of these compounds in various industrial processes. Predictive toxicological modeling on ionic liquids provides a rational assessment strategy and aids in developing suitable guidance for designing novel analogues. The present study attempts to explore the chemical features of ionic liquids responsible for their ecotoxicity towards the green algae Scenedesmus vacuolatus by developing mathematical models using extended topochemical atom (ETA) indices along with other categories of chemical descriptors. The entire study has been conducted with reference to the OECD guidelines for QSAR model development using predictive classification and regression modeling strategies. The best models from both the analyses showed that ecotoxicity of ionic liquids can be decreased by reducing chain length of cationic substituents and increasing hydrogen bond donor feature in cations, and replacing bulky unsaturated anions with simple saturated moiety having less lipophilic heteroatoms. Copyright © 2013 Elsevier Ltd. All rights reserved.

Temperature- and pressure-dependent infrared spectroscopy of 1-butyl-3-methylimidazolium trifluoromethanesulfonate: A dipolar coupling theory analysis

NASA Astrophysics Data System (ADS)

Burba, Christopher M.; Chang, Hai-Chou

2018-03-01

Continued growth and development of ionic liquids requires a thorough understanding of how cation and anion molecular structure defines the liquid structure of the materials as well as the various properties that make them technologically useful. Infrared spectroscopy is frequently used to assess molecular-level interactions among the cations and anions of ionic liquids because the intramolecular vibrational modes of the ions are sensitive to the local potential energy environments in which they reside. Thus, different interaction modes among the ions may lead to different spectroscopic signatures in the vibrational spectra. Charge organization present in ionic liquids, such as 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([C4mim]CF3SO3), is frequently modeled in terms of a quasicrystalline structure. Highly structured quasilattices enable the dynamic coupling of vibrationally-induced dipole moments to produce optical dispersion and transverse optical-longitudinal optical (TO-LO) splitting of vibrational modes of the ionic liquid. According to dipolar coupling theory, the degree of TO-LO splitting is predicted to have a linear dependence on the number density of the ionic liquid. Both temperature and pressure will affect the number density of the ionic liquid and, therefore, the amount of TO-LO splitting for this mode. Therefore, we test these relationships through temperature- and pressure-dependent FT-IR spectroscopic studies of [C4mim]CF3SO3, focusing on the totally symmetric Ssbnd O stretching mode for the anion, νs(SO3). Increased temperature decreases the amount of TO-LO splitting for νs(SO3), whereas elevated pressure is found to increase the amount of band splitting. In both cases, the experimental observations follow the general predictions of dipolar coupling theory, thereby supporting the quasilattice model for this ionic liquid.

Ionic-liquid-based dispersive liquid-liquid microextraction combined with magnetic solid-phase extraction for the determination of aflatoxins B1 , B2 , G1 , and G2 in animal feeds by high-performance liquid chromatography with fluorescence detection.

PubMed

Zhao, Jiao; Zhu, Yan; Jiao, Yang; Ning, Jinyan; Yang, Yaling

2016-10-01

A novel two-step extraction technique combining ionic-liquid-based dispersive liquid-liquid microextraction with magnetic solid-phase extraction was developed for the preconcentration and separation of aflatoxins in animal feedstuffs before high-performance liquid chromatography coupled with fluorescence detection. In this work, ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate was used as the extractant in dispersive liquid-liquid microextraction, and hydrophobic pelargonic acid modified Fe 3 O 4 magnetic nanoparticles as an efficient adsorbent were applied to retrieve the aflatoxins-containing ionic liquid. Notably, the target of magnetic nanoparticles was the ionic liquid rather than the aflatoxins. Because of the rapid mass transfer associated with the dispersive liquid-liquid microextraction and magnetic solid phase steps, fast extraction could be achieved. The main parameters affecting the extraction recoveries of aflatoxins were investigated and optimized. Under the optimum conditions, vortexing at 2500 rpm for 1 min in the dispersive liquid-liquid microextraction and magnetic solid-phase extraction and then desorption by sonication for 2 min with acetonitrile as eluent. The recoveries were 90.3-103.7% with relative standard deviations of 3.2-6.4%. Good linearity was observed with correlation coefficients ranged from 0.9986 to 0.9995. The detection limits were 0.632, 0.087, 0.422 and 0.146 ng/mL for aflatoxins B 1 , B2, G1, and G2, respectively. The results were also compared with the pretreatment method carried out by conventional immunoaffinity columns. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

New electrolytes for aluminum production: Ionic liquids

NASA Astrophysics Data System (ADS)

Zhang, Mingming; Kamavarum, Venkat; Reddy, Ramana G.

2003-11-01

In this article, the reduction, refining/recycling, and electroplating of aluminum from room-temperature molten salts are reviewed. In addition, the characteristics of several non-conventional organic solvents, electrolytes, and molten salts are evaluated, and the applicability of these melts for production of aluminum is discussed with special attention to ionic liquids. Also reviewed are electrochemical processes and conditions for electrodeposition of aluminum using ionic liquids at near room temperatures.

Multi-Scale Simulation of High Energy Density Ionic Liquids

DTIC Science & Technology

2007-06-19

and simulation of ionic liquids (ILs). A polarizable model was developed to simulate ILs more accurately at the atomistic level. A multiscale coarse...propellant, 1- hydroxyethyl-4-amino-1, 2, 4-triazolium nitrate (HEATN), were studied with the all-atom polarizable model. The mechanism suggested for HEATN...with this AFOSR-supported project, a polarizable forcefield for the ionic liquids such as 1-ethyl-3-methylimidazolium nitrate (EMIM*/NO3-) was

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

DOEpatents

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

2014-08-19

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

Research and Development of Energetic Ionic Liquids

DTIC Science & Technology

2012-03-01

Navy/ AF ) – USAF AF - M315E • Propellant uses ionic liquids to yield low vapor toxicity 22 – Sweden/ECAPS LMP-103S • Propellant uses ADN-based formulation...hydrazine replacement monopropellant objectives, relevant monopropellant properties, AF -M1028A monopropellant composition and physical properties...thruster tests of AF -M1028A, ionic liquids as explosives, predictive toxicology, predictive methods expected payoff. AFRL continues efforts in energetic

Influence of Zwitterions on Thermomechanical Properties and Morphology of Acrylic Copolymers: Implications for Electroactive Applications

DTIC Science & Technology

2011-09-30

transducers from branched sulfonated polysulfones.7 The mechanical strength of the membranes drastically decreased upon introduction of ionic liquids to... liquids ,8 and zwitterionomers maintained mechanical strengths upon swelling with 10 wt % ionic liquid . Zwitterions are chargedmolecules that contain...water purification5 to biotechnology.6 A unique combination of physical properties of ionomeric membranes is the ionic con- ductivity of lowmolar mass

Novel Nanocomposite Structures as Active and Passive Barrier Materials

DTIC Science & Technology

2010-06-01

during the course of this ARO-funded project. The development of a novel polymer material based on a diol-functionalized room-temperature ionic liquid ...material based on a diol-functionalized room- temperature ionic liquid (RTIL) monomer led to fabrication of membranes, which were tested for their...stimulant vapor. Technical Report A polymerizable room-temperature ionic liquid (4, Figure 1) was chosen as the starting material for making poly(RTIL

NMR Studies of Mass Transport in New Conducting Media for Fuel Cells

DTIC Science & Technology

2009-01-01

PEM films, for example those containing phosphoric acid and ionic liquids . Dynamical processes are probed at the short range by spin-lattice...structural environments of muticomponent PEM films, for example those containing phosphoric acid and ionic liquids . Dynamical processes are probed at the...correlation between water diffusivity and proton conductivity in the nanocomposites Transport properties of several ionic liquids (IL’s) and membranes

Fabrication of an ionic-liquid-based polymer monolithic column and its application in the fractionation of proteins from complex biosamples.

PubMed

Zhang, Doudou; Zhang, Qian; Bai, Ligai; Han, Dandan; Liu, Haiyan; Yan, Hongyuan

2018-05-01

An ionic-liquid-based polymer monolithic column was synthesized by free radical polymerization within the confines of a stainless-steel column (50 mm × 4.6 mm id). In the processes, ionic liquid and stearyl methacrylate were used as dual monomers, ethylene glycol dimethacrylate as the cross-linking agent, and polyethylene glycol 200 and isopropanol as co-porogens. Effects of the prepolymerization solution components on the properties of the resulting monoliths were studied in detail. Scanning electron microscopy, nitrogen adsorption-desorption measurements, and mercury intrusion porosimetry were used to investigate the morphology and pore size distribution of the prepared monoliths, which showed that the homemade ionic-liquid-based monolith column possessed a relatively uniform macropore structure with a total macropore specific surface area of 44.72 m 2 /g. Compared to a non-ionic-liquid-based monolith prepared under the same conditions, the ionic-liquid-based monolith exhibited excellent selectivity and high performance for separating proteins from complex biosamples, such as egg white, snailase, bovine serum albumin digest solution, human plasma, etc., indicating promising applications in the fractionation and analysis of proteins from the complex biosamples in proteomics research. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

PubMed

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

2016-01-15

A new approach for ionic liquid based enzyme-assisted extraction (ILEAE) of chlorogenic acid (CGA) from Eucommia ulmoides is presented in which enzyme pretreatment was used in ionic liquids aqueous media to enhance extraction yield. For this purpose, the solubility of CGA and the activity of cellulase were investigated in eight 1-alkyl-3-methylimidazolium ionic liquids. Cellulase in 0.5 M [C6mim]Br aqueous solution was found to provide better performance in extraction. The factors of ILEAE procedures including extraction time, extraction phase pH, extraction temperatures and enzyme concentrations were investigated. Moreover, the novel developed approach offered advantages in term of yield and efficiency compared with other conventional extraction techniques. Scanning electronic microscopy of plant samples indicated that cellulase treated cell wall in ionic liquid solution was subjected to extract, which led to more efficient extraction by reducing mass transfer barrier. The proposed ILEAE method would develope a continuous process for enzyme-assisted extraction including enzyme incubation and solvent extraction process. In this research, we propose a novel view for enzyme-assisted extraction of plant active component, besides concentrating on enzyme facilitated cell wall degradation, focusing on improvement of bad permeability of ionic liquids solutions. Copyright © 2015 Elsevier B.V. All rights reserved.

Topological defects in electric double layers of ionic liquids at carbon interfaces

DOE PAGES

Black, Jennifer M.; Okatan, Mahmut Baris; Feng, Guang; ...

2015-06-07

The structure and properties of the electrical double layer in ionic liquids is of interest in a wide range of areas including energy storage, catalysis, lubrication, and many more. Theories describing the electrical double layer for ionic liquids have been proposed, however a full molecular level description of the double layer is lacking. To date, studies have been predominantly focused on ion distributions normal to the surface, however the 3D nature of the electrical double layer in ionic liquids requires a full picture of the double layer structure not only normal to the surface, but also in plane. Here wemore » utilize 3D force mapping to probe the in plane structure of an ionic liquid at a graphite interface and report the direct observation of the structure and properties of topological defects. The observation of ion layering at structural defects such as step-edges, reinforced by molecular dynamics simulations, defines the spatial resolution of the method. Observation of defects allows for the establishment of the universality of ionic liquid behavior vs. separation from the carbon surface and to map internal defect structure. In conclusion, these studies offer a universal pathway for probing the internal structure of topological defects in soft condensed matter on the nanometer level in three dimensions.« less