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Sample records for aqueous ionic melts

  1. Aqueous solutions of ionic liquids: microscopic assembly

    NARCIS (Netherlands)

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

    2016-01-01

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

  2. Lipid Bilayer Formation in Aqueous Solutions of Ionic Liquids

    OpenAIRE

    Young, Taylor Tront

    2012-01-01

    The formation of lipid bilayer membranes between droplets of ionic liquid is presented as a means of forming functional bimolecular networks for use in sensor applications. Ionic liquids are salts that have a number of useful properties, such as low melting points making them liquid at room temperature and exceedingly low vapor pressure. Ionic liquids have seen recent popularity as environmentally friendly industrial solvent alternatives. Our research demonstrates that it is possible to cons...

  3. Recovery of Ionic Liquids from aqueous solution by Nanofiltration

    OpenAIRE

    Fernández Dámaso, José Francisco

    2011-01-01

    The T-SAR methodology was combined with membrane characterization methods. An application of the combined approach was demonstrated with two commercial nanofiltration membranes and it was possible to successfully predict their performance for the recovery of ionic liquids from aqueous solution. Using model solutions of Pyr16 (CF3SO2)2N, it could be evidenced the formation of a new phase of ionic liquid during the concentration process. In this case, 66% of the ionic liquid was separated and t...

  4. Modern electrochemical processes and technologies in ionic melts

    Directory of Open Access Journals (Sweden)

    Omelchuk A.

    2003-01-01

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

  5. Ionic association and interactions in aqueous methylsulfate alkyl-imidazolium-based ionic liquids

    International Nuclear Information System (INIS)

    Highlights: • Viscosity and electrical conductivity were determined in aqueous ionic liquids. • For the shorter IL the viscosity was lower and the electrical conductivity higher. • NMR and IR were used to study ionic association and interactions in aqueous ILs. • The main change in the ionic association was only observed for high water contents. • In IR, the SO3 asymmetric stretching band is a probe of structural changes. - Abstract: Several experimental techniques were used to study ionic association and interactions in aqueous [C1C2Im][MeSO4], 1-ethyl-3-methylimidazolium methylsulfate, and [C1C4Im][MeSO4], 1-butyl-3-methylimidazolium methylsulfate. Two transport properties, viscosity and electrical conductivity, were determined for these two binary mixtures. For a better assessment of the ionic association and the perturbation of water into the molecular structure of the ionic liquid, diffusion coefficients of ions and water molecules were obtained by NMR spectroscopy while molecular interactions were probed by IR spectroscopy. The comparison of the two ionic liquids shows that for the shorter alkyl chain the viscosity was lower and the electrical conductivity was higher. While the viscosity of the mixture drops already with small additions of water, the electrical conductivity of the solution is only significantly increased for high water concentrations. A maximum is observed for compositions around xwater = (0.90 to 0.95). The SO3 asymmetric stretching band of the IR spectrum can be used as a probe to observe the evolution of the structure around the anion which was mainly occurring for high concentrations of water. Several experimental techniques show than the main change in the ionic association was only observed for high water contents (water mole fraction > 0.8)

  6. Density and ionic structure of NdF_3-LiF melts

    Institute of Scientific and Technical Information of China (English)

    胡宪伟; 王兆文; 高炳亮; 石忠宁; 刘风国; 曹晓舟

    2010-01-01

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

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

    Science.gov (United States)

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

    2016-02-01

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

  8. Thermodynamics of dilute aqueous solutions of imidazolium based ionic liquids

    International Nuclear Information System (INIS)

    Research highlights: → The thermodynamic behaviour of aqueous imidazolium ILs has been investigated. → Volumetric and ultrasonic results indicated the hydrophobic hydration of ILs. → Viscometric studies revealed studied ionic liquids as water-structure makers. → Hydration number increased with increase in alkyl chain length of the cation. - Abstract: Experimental measurements of density ρ, speed of sound u, and viscosity η of aqueous solutions of various 1-alkyl-3-methylimidazolium based ionic liquid (IL) solutions have been performed in dilute concentration regime at 298.15 K to get insight into hydration behaviour of ILs. The investigated ILs are based on 1-alkyl-3-methylimidazolium cation, [Cnmim] having [BF4]-, [Cl]-, [C1OSO3]-, and [C8OSO3]- as anions where n = 4 or 8. Several thermodynamic parameters like apparent molar volume φV, isentropic compressibility βs, and viscosity B-coefficients have been derived from experimental data. Limiting value of apparent molar volume has been discussed in terms of intrinsic molar volume (Vint) molar electrostriction volume (Velec), molar disordered (Vdis), and cage volume (Vcage). Viscosity B-coefficients have been used to quantify the kosmotropic or chaotropic nature of ILs. Hydration number of ILs obtained using elctrostriction volume, isentropic compressibility, viscosity, and differential scanning calorimetry have been found to be comparative within the experimental error. The hydrophobic hydration has found to play an important role in hydration of ILs as compared to hydration due to hydrogen bonding and electrostriction. Limiting molar properties, hydration numbers, and B-coefficients have been discussed in terms of alkyl chain length of cation or nature of anion.

  9. Extraction Equilibrium of Acrylic Acid by Aqueous Two-Phase Systems Using Hydrophilic Ionic Liquids

    International Nuclear Information System (INIS)

    As an effective method for extraction of acrylic acid, aqueous two-phase systems based on morpholinium ionic liquids were used in this study. Effects of the alkyl chain length of cation in morpholinium ionic liquids on phase diagram and extraction efficiencies were investigated. Experimental results show that aqueous two phase systems can be formed by adding appropriate amount of morpholinium ionic liquids to aqueous K2HPO4 solutions. It can be found that the ability of morpholinium ionic liquids for phase separation followed the order [HMMor][Br]>[OMMor][Br]>[BMMor][Br]>[EMMor][Br]. There was little difference between binodal curves of imidazolium ionic liquids and those of morpholinium ionic liquids. 50-90% of the extraction efficiency was observed for acrylic acid by aqueous two phase extraction of acrylic acid with morpholinium ionic liquids. It can be concluded that morpholinium ionic liquids/K2HPO4 were effective for aqueous two phases extraction of acrylic acid comparing to imidazolium ionic liquids/K2HPO4 systems because of their lower cost

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

    Science.gov (United States)

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

    2015-10-20

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

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

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

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

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

    International Nuclear Information System (INIS)

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

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

    Indian Academy of Sciences (India)

    Manish Agarwal; Charusita Chakravarty

    2009-09-01

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

  14. Actinide, lanthanide and fission product speciation and electrochemistry in high and low temperature ionic melts

    International Nuclear Information System (INIS)

    There is currently a great deal of research interest in the development of molten salt technology, both classical high temperature melts and low temperature ionic liquids, for the electrochemical separation of the actinides from spent nuclear fuel. We are interested in gaining a better understanding of actinide and key fission product speciation and electrochemical properties in a range of melts. Our studies in high temperature alkali metal melts (including LiCl and LiCl-KCl and CsCl-NaCl eutectics) have focussed on in-situ species of U, Th, Tc and Ru using X-ray absorption spectroscopy (XAS, both EXAFS and XANES) and electronic absorption spectroscopy (EAS). We report unusual actinide speciation in high temperature melts and an evaluation of the likelihood of Ru or Tc volatilization during plant operation. Our studies in lower temperature melts (ionic liquids) have focussed on salts containing tertiary alkyl group 15 cations and the bis(tri-fluor-methyl)sulfonyl)imide anion, melts which we have shown to have exceptionally wide electrochemical windows. We report Ln, Th, U and Np speciation (XAS, EAS and vibrational spectroscopy) and electrochemistry in these melts and relate the solution studies to crystallographic characterised benchmark species. (authors)

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    R. Moretti

    2005-06-01

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

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

    Directory of Open Access Journals (Sweden)

    Anfinogenov A.I.

    2003-01-01

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

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

    Weiss, Volker C

    2015-10-14

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

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

    OpenAIRE

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

    2013-01-01

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

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

    Science.gov (United States)

    Atanassova, Maria; Mazan, Valérie; Billard, Isabelle

    2015-06-01

    Aqueous-ionic liquid (A-IL) biphasic systems have been examined in terms of deuterated water, acid, and IL cation and anion mutual solubilities in the upper (water-rich, in mole fraction) and lower phase of aqueous/IL biphasic systems at ambient temperature. The biphasic mixtures were composed of deuterated acids of various concentrations (mainly DCl, DNO(3), and DClO(4) from 10(-2) to 10(-4)  M) and five ionic liquids of the imidazolium family with a hydrophobic anion (CF(3)SO(2))(2) N(-), that is, [C1 Cn im][Tf(2)N], (n=2, 4, 6, 8 and 10). The analytical techniques applied were (1) H NMR, (19) F NMR, Karl-Fischer titration, pH potentiometry for IL cations and anions, and water and acid determination. The effects of the ionic strength (μ=0.1 M NaCl and NaNO(3) as well as μ=0.1 M, 0.2 M and 0.4 M NaClO(4), according to the investigated acid), the nature of the IL cation, and the nature of the mineral acid on the solubilities of the (D(2)O, D(+), Tf(2)N(-), C1 Cn im(+)) entities in the lower or upper phases were determined. The addition of sodium perchlorate was found to enhance the Tf(2)N(-) solubility while inhibiting the solubility of the ionic liquid cation. Differences in IL cation and anion solubilities of up to 42 mM were evidenced. The consequences for the characterization of the aqueous biphasic system, the solvent extraction process of the metal ions, and the ecological impact of the ILs are discussed. PMID:25787248

  2. Phase diagrams of ionic liquids-based aqueous biphasic systems as a platform for extraction processes

    International Nuclear Information System (INIS)

    Highlights: • Novel ABS based in ionic liquids were determined as a platform for distinct extraction processes. • The effect of pH, IL cation core, alkyl side chain length, IL anion nature, and salt nature on the ABS formation was investigated. • The ability to form ABS increases with the pH and alkyl chain length for all systems studied. • The ILs cation core and anion nature effect on the ABS formation is dominated by the IL (hydrophobic/hydrophilic) nature. • The effect of the different salts depends of the ionic liquid nature and salt valency. - Abstract: In the past few years, ionic liquid-based aqueous biphasic systems have become the subject of considerable interest as a promising technique for the extraction and purification of several macro/biomolecules. Aiming at developing guidelines for more benign and efficient extraction processes, phase diagrams for aqueous biphasic systems composed of ionic liquids and inorganic/organic salts are here reported. Several combinations of ionic liquid families (imidazolium, pyridinium, phosphonium, quaternary ammonium and cholinium) and salts [potassium phosphate buffer (KH2PO4/K2HPO4 at pH 7), potassium citrate buffer (C6H5K3O7/C6H8O7 at pH 5, 6, 7 and 8) and potassium carbonate (K2CO3 at pH ∼13)] were evaluated to highlight the influence of the ionic liquid structure (cation core, anion and alkyl chain length), the pH and the salt nature on the formation of aqueous biphasic systems. The binodal curves and respective tie-lines reported for these systems were experimentally determined at (298 ± 1) K. In general, the ability to promote the aqueous biphasic systems formation increases with the pH and alkyl chain length. While the influence of the cation core and anion nature of the ionic liquids on their ability to form aqueous biphasic systems closely correlates with ionic liquids capacity to be hydrated by water, the effect of the different salts depends of the ionic liquid nature and salt valency

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

    OpenAIRE

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

    2010-01-01

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

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    Mohammad Tariq

    2013-03-01

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

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

    Science.gov (United States)

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

    2016-09-01

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

  7. Mean ionic activity coefficients in aqueous NaCl solutions from molecular dynamics simulations

    Energy Technology Data Exchange (ETDEWEB)

    Mester, Zoltan; Panagiotopoulos, Athanassios Z., E-mail: azp@princeton.edu [Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544 (United States)

    2015-01-28

    The mean ionic activity coefficients of aqueous NaCl solutions of varying concentrations at 298.15 K and 1 bar have been obtained from molecular dynamics simulations by gradually turning on the interactions of an ion pair inserted into the solution. Several common non-polarizable water and ion models have been used in the simulations. Gibbs-Duhem equation calculations of the thermodynamic activity of water are used to confirm the thermodynamic consistency of the mean ionic activity coefficients. While the majority of model combinations predict the correct trends in mean ionic activity coefficients, they overestimate their values at high salt concentrations. The solubility predictions also suffer from inaccuracies, with all models underpredicting the experimental values, some by large factors. These results point to the need for further ion and water model development.

  8. Mean ionic activity coefficients in aqueous NaCl solutions from molecular dynamics simulations

    International Nuclear Information System (INIS)

    The mean ionic activity coefficients of aqueous NaCl solutions of varying concentrations at 298.15 K and 1 bar have been obtained from molecular dynamics simulations by gradually turning on the interactions of an ion pair inserted into the solution. Several common non-polarizable water and ion models have been used in the simulations. Gibbs-Duhem equation calculations of the thermodynamic activity of water are used to confirm the thermodynamic consistency of the mean ionic activity coefficients. While the majority of model combinations predict the correct trends in mean ionic activity coefficients, they overestimate their values at high salt concentrations. The solubility predictions also suffer from inaccuracies, with all models underpredicting the experimental values, some by large factors. These results point to the need for further ion and water model development

  9. Mean ionic activity coefficients in aqueous NaCl solutions from molecular dynamics simulations.

    Science.gov (United States)

    Mester, Zoltan; Panagiotopoulos, Athanassios Z

    2015-01-28

    The mean ionic activity coefficients of aqueous NaCl solutions of varying concentrations at 298.15 K and 1 bar have been obtained from molecular dynamics simulations by gradually turning on the interactions of an ion pair inserted into the solution. Several common non-polarizable water and ion models have been used in the simulations. Gibbs-Duhem equation calculations of the thermodynamic activity of water are used to confirm the thermodynamic consistency of the mean ionic activity coefficients. While the majority of model combinations predict the correct trends in mean ionic activity coefficients, they overestimate their values at high salt concentrations. The solubility predictions also suffer from inaccuracies, with all models underpredicting the experimental values, some by large factors. These results point to the need for further ion and water model development. PMID:25637995

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

    Directory of Open Access Journals (Sweden)

    Andreas Taubert

    2009-11-01

    Full Text Available Injection of a mixture of HAuCl4 and cellulose dissolved in the ionic liquid (IL 1-butyl-3-methylimidazolium chloride [Bmim]Cl into aqueous NaBH4 leads to colloidal gold nanoparticle/cellulose hybrid precipitates. This process is a model example for a very simple and generic approach towards (noble metal/cellulose hybrids, which could find applications in sensing, sterile filtration, or as biomaterials.

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2014-09-01

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

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

    Directory of Open Access Journals (Sweden)

    Suk Young Choi

    2012-01-01

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    DEFF Research Database (Denmark)

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

    2009-01-01

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

  17. Ionic liquid-salt based aqueous biphasic system separation of 109Cd from silver target

    International Nuclear Information System (INIS)

    The Aqueous Biphasic Systems (ABS) is becoming more important from green chemistry point of view replacing conventional liquid-liquid extraction system. The most of the aqueous biphasic systems reported in the literature are based on Polyethylene glycol (PEG) with different salts. Although ABS based on water soluble room temperature ionic liquid (RTIL) 1-butyl-3-methylimidazolium Chloride ((bmim)CI) and concentrated solutions of kosmotropic salt K2HPO4 was reported in 2007 but the efficiency of this system for metal partitioning has been rarely explored. We report for the first time separation of no-carrier-added (NCA) 109Cd from the α-particle irradiated Ag target using this ABS

  18. Viscometric studies of interactions between ionic liquid 1-octyl-3-methyl-imidazolium bromide and polyvinyl pyrrolidone in aqueous solutions

    International Nuclear Information System (INIS)

    Highlights: • Viscosities of PVP in aqueous solution of IL are measured. • The flow activation energies are calculated. • The flow activation energies are correlated in terms of polymer concentration. • Intrinsic viscosity of PVP is decreased by increasing temperature. - Abstract: Ionic liquids are investigated as solvents for polymerization processes, as plasticizers of various kinds of polymers and as components of the polymeric matrixes. In this research, viscosity of polyvinyl pyrrolidone in aqueous solution of ionic liquid, 1-octyl-3-methyl imidazolium bromide are measured at various temperatures. The flow activation energies are calculated and correlated in terms of polymer concentration. From sign of the initial slope of the activation energy versus polymer concentration at zero concentration, it is concluded that thermodynamic quality of ionic liquid aqueous solutions are reduced by increasing temperature. The value of the intrinsic viscosity of polyvinyl pyrrolidone was determined using Huggins equation and thermodynamic parameters of this polymer were calculated on the basis of intrinsic viscosity. Also the effect of ionic liquid, 1-octyl-3-methyl imidazolium bromide on the thermodynamic parameters of dilute aqueous polyvinyl pyrrolidone solutions, such as (polymer + solvent) interaction parameter, theta temperature, the heat of dilution parameter and the entropy of dilution parameter was investigated. Results suggest that the thermodynamic quality of water was increased slightly by the addition of ionic liquid in aqueous solution of polyvinyl pyrrolidone

  19. Separation of supercritical slab-fluids to form aqueous fluid and melt components in subduction zone magmatism

    OpenAIRE

    Kawamoto, Tatsuhiko; Kanzaki, Masami; Mibe, Kenji; Matsukage, Kyoko N.; Ono, Shigeaki

    2012-01-01

    Subduction-zone magmatism is triggered by the addition of H2O-rich slab-derived components: aqueous fluid, hydrous partial melts, or supercritical fluids from the subducting slab. Geochemical analyses of island arc basalts suggest two slab-derived signatures of a melt and a fluid. These two liquids unite to a supercritical fluid under pressure and temperature conditions beyond a critical endpoint. We ascertain critical endpoints between aqueous fluids and sediment or high-Mg andesite (HMA) me...

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

    Directory of Open Access Journals (Sweden)

    Cláudia L. S. Louros

    2010-04-01

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

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

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

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

  2. Association of ionic liquids with cationic dyes in aqueous solution: A thermodynamic study

    International Nuclear Information System (INIS)

    Highlights: ► Precipitate was formed between cationic dye and ionic liquid in aqueous solution. ► Precipitates are 1:1 formed by cation of the dyes and anion of the ionic liquids. ► Association constants decrease with increasing temperature. ► The associates can be used as active materials of ion-selective electrode. - Abstract: In this paper, the interactions between cationic dyes and the ionic liquids (ILs) have been studied by 31P nuclear magnetic resonance (NMR), UV–Vis spectroscopy and conductometric measurements at different temperatures. It was shown that a decrease in the measured specific conductance of the (dye + IL) mixtures was caused by the formation of non-conducting or less conducting (dye + IL) associates. The associates were formed by 1:1 ratio of cation of the cationic dyes and anion of the ILs by using the 31P NMR and UV–Vis spectroscopy methods. The association constants were calculated by theoretical model based on the deviation from linear behavior, and the association constants were as high as 106 (L · mol−1)2. Thermodynamic results imply that the formation process of association was exothermic nature. It is expected that the associates reported here would have promising application as active materials for the preparation of ion-selective electrode used in the determination of ILs concentrations.

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2016-05-19

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

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

    OpenAIRE

    Senthilkumar Rathnasamy; R.Kumaresan2

    2013-01-01

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

  6. Poly(ionic liquid)s as phase splitting promoters in aqueous biphasic systems.

    Science.gov (United States)

    João, Karen G; Tomé, Liliana C; Isik, Mehmet; Mecerreyes, David; Marrucho, Isabel M

    2015-11-01

    Aqueous biphasic systems (ABSs) provide a sustainable and efficient alternative to conventional liquid-liquid extraction techniques with volatile organic solvents, and can be used for the extraction, recovery, and purification of diverse solutes. In this work, and for the first time, ABSs composed of poly(ionic liquid)s (PILs) and inorganic salts were measured at 25 °C and atmospheric pressure. New PILs having pyrrolidinium polycations combined with different counter-anions, namely acetate [Ac](-), trifluoroacetate [TFAc](-), hexanoate [Hex](-), adipate [Adi](-), and citrate [Cit](-) were synthesized, by a simple and environmentally-friendly procedure, and characterized. The effect of the PIL features, namely molecular weight and anionic character, and other experimental variables, such as temperature, on the phase splitting ability was researched. The aptitude of the studied ABS to be implemented as separation technologies was also evaluated through the use of a model biomolecule, tryptophan. PMID:26421939

  7. Ionic liquids based aqueous biphasic systems: Effect of the alkyl chains in the cation versus in the anion

    International Nuclear Information System (INIS)

    Highlights: • Alkyl-3-methylimidazolium alkylsulfonate ILs for implemention of aqueous biphasic systems. • Study of the effect of alkyl chain length and position on ILs hydrophobicity. • Evaluation of ILs extractive power on L-tryptophan aqueous solutions. • The alkyl chain in the anion contributes more to the hydrophobicity of the IL. • Less hydrophobic ILs have the better extraction coefficients for L-tryptophan. -- Abstract: The use of alkyl-3-methylimidazolium alkylsulfonate ionic liquids for implementing aqueous biphasic systems is studied in this work for the first time. The ability of high charge density inorganic salts, such as K3PO4, to promote phase segregation in aqueous solutions containing the ionic liquids 1,3-dimethylimidazolium methylsulfonate ([C1mim][C1SO3]), 1-ethyl-3-methylimidazolium hexylsulfonate ([C2mim][C6SO3]), 1-ethyl-3-methylimidazolium butylsulfonate ([C2mim][C4SO3]), 1-butyl-3-methylimidazolium methylsulfonate ([C4mim][C1SO3]), 1-butyl-3-methylimidazolium ethylsulfonate ([C4mim][C2SO3]), 1-pentyl-3-methylimidazolium methylsulfonate ([C5mim][C1SO3]), 1-hexyl-3-methylimidazolium methylsulfonate ([C6mim][C1SO3]) and 1-hexyl-3-methylimidazolium ethylsulfonate ([C6mim][C2SO3]) was experimentally determined at 298.15 K and atmospheric pressure. In general, the hydrophobicity of the ionic liquids studied is affected by the increase of the alkyl chain length. However, the position of the alkyl chain, whether in the cation or in the anion affects in a different way the lipophilic effect of the ionic liquid. Two ionic liquids with the same number of carbon atoms, the one with a longer chain in the anion is the more hydrophobic. Furthermore, four ionic liquids were chosen to extract the aminoacid L-tryptophan from aqueous solutions. The chain lengths of the anion or cation were fixed and the partition coefficients compared. The extractions, carried out at 298.15 K, showed the good extractive power of these ionic liquids and also that

  8. Colloidal behavior of aqueous montmorillonite suspensions in the presence of non-ionic polymer

    Science.gov (United States)

    Gareche, M.; Azri, N.; Allal, A.; Zeraibi, N.

    2015-04-01

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

  9. Separation of supercritical slab-fluids to form aqueous fluid and melt components in subduction zone magmatism

    Science.gov (United States)

    Kawamoto, Tatsuhiko; Kanzaki, Masami; Mibe, Kenji; Ono, Shigeaki

    2012-01-01

    Subduction-zone magmatism is triggered by the addition of H2O-rich slab-derived components: aqueous fluid, hydrous partial melts, or supercritical fluids from the subducting slab. Geochemical analyses of island arc basalts suggest two slab-derived signatures of a melt and a fluid. These two liquids unite to a supercritical fluid under pressure and temperature conditions beyond a critical endpoint. We ascertain critical endpoints between aqueous fluids and sediment or high-Mg andesite (HMA) melts located, respectively, at 83-km and 92-km depths by using an in situ observation technique. These depths are within the mantle wedge underlying volcanic fronts, which are formed 90 to 200 km above subducting slabs. These data suggest that sediment-derived supercritical fluids, which are fed to the mantle wedge from the subducting slab, react with mantle peridotite to form HMA supercritical fluids. Such HMA supercritical fluids separate into aqueous fluids and HMA melts at 92 km depth during ascent. The aqueous fluids are fluxed into the asthenospheric mantle to form arc basalts, which are locally associated with HMAs in hot subduction zones. The separated HMA melts retain their composition in limited equilibrium with the surrounding mantle. Alternatively, they equilibrate with the surrounding mantle and change the major element chemistry to basaltic composition. However, trace element signatures of sediment-derived supercritical fluids remain more in the melt-derived magma than in the fluid-induced magma, which inherits only fluid-mobile elements from the sediment-derived supercritical fluids. Separation of slab-derived supercritical fluids into melts and aqueous fluids can elucidate the two slab-derived components observed in subduction zone magma chemistry. PMID:23112158

  10. Separation of supercritical slab-fluids to form aqueous fluid and melt components in subduction zone magmatism.

    Science.gov (United States)

    Kawamoto, Tatsuhiko; Kanzaki, Masami; Mibe, Kenji; Matsukage, Kyoko N; Ono, Shigeaki

    2012-11-13

    Subduction-zone magmatism is triggered by the addition of H(2)O-rich slab-derived components: aqueous fluid, hydrous partial melts, or supercritical fluids from the subducting slab. Geochemical analyses of island arc basalts suggest two slab-derived signatures of a melt and a fluid. These two liquids unite to a supercritical fluid under pressure and temperature conditions beyond a critical endpoint. We ascertain critical endpoints between aqueous fluids and sediment or high-Mg andesite (HMA) melts located, respectively, at 83-km and 92-km depths by using an in situ observation technique. These depths are within the mantle wedge underlying volcanic fronts, which are formed 90 to 200 km above subducting slabs. These data suggest that sediment-derived supercritical fluids, which are fed to the mantle wedge from the subducting slab, react with mantle peridotite to form HMA supercritical fluids. Such HMA supercritical fluids separate into aqueous fluids and HMA melts at 92 km depth during ascent. The aqueous fluids are fluxed into the asthenospheric mantle to form arc basalts, which are locally associated with HMAs in hot subduction zones. The separated HMA melts retain their composition in limited equilibrium with the surrounding mantle. Alternatively, they equilibrate with the surrounding mantle and change the major element chemistry to basaltic composition. However, trace element signatures of sediment-derived supercritical fluids remain more in the melt-derived magma than in the fluid-induced magma, which inherits only fluid-mobile elements from the sediment-derived supercritical fluids. Separation of slab-derived supercritical fluids into melts and aqueous fluids can elucidate the two slab-derived components observed in subduction zone magma chemistry. PMID:23112158

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-03-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-01-01

    As we advance our understanding, ionic liquids (ILs) are finding ever broader scope within the chemical sciences including, most recently, pharmaceutical, enzymatic, and bioanalytical applications. With examples of enzymatic activity reported in both neat ILs and in IL/water mixtures, enzymes are frequently assumed to adopt a quasi-native conformation, even if little work has been carried out to date toward characterizing the conformation, dynamics, active-site perturbation, cooperativity of unfolding transitions, free energy of stabilization, or aggregation/oligomerization state of enzymes in the presence of an IL solvent component. In this study, human serum albumin and equine heart cytochrome c were characterized in aqueous solutions of the fully water-miscible IL 1-butyl-3-methylimidazolium chloride, [bmim]Cl, by small-angle neutron and X-ray scattering. At [bmim]Cl concentrations up to 25 vol.%, these two proteins were found to largely retain their higher-order structures whereas both proteins become highly denatured at the highest IL concentration studied here (i.e., 50 vol.% [bmim]Cl). The response of these proteins to [bmim]Cl is analogous to their behavior in the widely studied denaturants guanidine hydrochloride and urea which similarly lead to random coil conformations at excessive molar concentrations. Interestingly, human serum albumin dimerizes in response to [bmim]Cl, whereas cytochrome c remains predominantly in monomeric form. These results have important implications for enzymatic studies in aqueous IL media, as they suggest a facile pathway through which biocatalytic activity can be altered in these nascent and potentially green electrolyte systems.

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

    Science.gov (United States)

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

    2014-12-01

    To date, the extraction of genomic DNA is considered a bottleneck in the process of genetically modified organisms (GMOs) detection. Conventional DNA isolation methods are associated with long extraction times and multiple pipetting and centrifugation steps, which makes the entire procedure not only tedious and complicated but also prone to sample cross-contamination. In recent times, ionic liquids have emerged as innovative solvents for biomass processing, due to their outstanding properties for dissolution of biomass and biopolymers. In this study, a novel, easily applicable, and time-efficient method for the direct extraction of genomic DNA from biomass based on aqueous-ionic liquid solutions was developed. The straightforward protocol relies on extraction of maize in a 10 % solution of ionic liquids in aqueous phosphate buffer for 5 min at room temperature, followed by a denaturation step at 95 °C for 10 min and a simple filtration to remove residual biopolymers. A set of 22 ionic liquids was tested in a buffer system and 1-ethyl-3-methylimidazolium dimethylphosphate, as well as the environmentally benign choline formate, were identified as ideal candidates. With this strategy, the quality of the genomic DNA extracted was significantly improved and the extraction protocol was notably simplified compared with a well-established method. PMID:25381609

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-07-01

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

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

    International Nuclear Information System (INIS)

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

  17. Theoretical insights into the properties of amino acid ionic liquids in aqueous solution.

    Science.gov (United States)

    Zhu, Xueying; Ai, Hongqi

    2016-07-01

    This report presents a systematic investigation of the interactions of water molecule(s) with a series of amino acid cations (Gly(+), Ala(+), Val(+), and Leu(+)), halogen anions (Cl(-), Br(-), BF4 (-), and PF6 (-)), and clusters (GlyCl) n (n = 1-5). The results reveal that H-bonds between amino acid ionic liquids (AAILs) and water molecules are crucial to the properties of aqueous solution of AAILs. The properties of AAIL in water solution depend on the alkyl chain of the amino acid cation, the size of the halogen anion, and the number of water molecules, which provides a certain theoretical basis for the design and application of new AAILs. A series of calculations for some different models showed that quadruple-GlyCl hydrate represents a basic unit for the Gly-water binary system, and can be employed as the simplest model for studying an AAIL-water cluster. On the basis of this model, the effects of water on the hygroscopicity, speed of solubility, viscosity, density, solution enthalpy, and polarity of the AAIL were also predicted. Most importantly, unlike traditional ILs, the novel GlyCl-type AAIL favors interaction of its cationic part, rather than its anionic part, with surrounding water molecules, thus amino acid cationic ILs expand the types of IL available, increasing the choice of ILs for different purposes. We hope that the application of this AAIL in many fields will lead to optimization of this class of compound and be of benefit to the environment. Graphical Abstract Quadruple-GlyCl hydrate represents the basic unit for a GlyCl-water binary system, which can be employed as the simplest model for studying an amino acid ionic liquid (AAIL)-water cluster. The effects of available water on some properties of AAIL are predicted. GlyCl-type AAIL is a novel IL, which prefers its cationic part over its anionic part for interaction with surrounding water molecules. The properties of AAIL in water solution can be adjusted by varying the ion used and the

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

    Exerowa, Dotchi; Platikanov, Dimo

    2009-01-01

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

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

    OpenAIRE

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

    2014-01-01

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

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

    OpenAIRE

    Pilli, S; Mohanty, Kaustubha; Banerjee, Tamal

    2014-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Senthilkumar Rathnasamy

    2013-04-01

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-09-28

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

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

    Science.gov (United States)

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

    2015-09-28

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-09-15

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

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

    International Nuclear Information System (INIS)

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

  10. Search for a new greener technology for separation of NCA 97Ru from bulk Nb: ionic liquid based aqueous biphasic system

    International Nuclear Information System (INIS)

    Ionic-liquid (IL) based aqueous biphasic system was developed for the separation of no-carrier-added (NCA) 97Ru from bulk niobium target for the first time as greener separation technology. Room temperature ionic liquid, 1-butyl-3-methylimidazolium Chloride ((Bmim)Cl) against K2HPO4 as salt rich phase was employed to construct this IL-ABS system. In the typical experimental condition, 50 % NCA 97Ru was extracted into the ionic liquid phase without any contamination of Nb, with a separation factor of 5.3x103. (author)

  11. Partitioning of non-ionic surfactants between water and non-aqueous phase liquids (NAPLs) of chlorinated organics

    Science.gov (United States)

    KANG, S.; Jeong, H. Y.

    2013-12-01

    Due to the hydrophobic nature, chlorinated organic compounds penetrate soil and groundwater to form non-aqueous phase liquids (NAPLs). At the sites contaminated with such NAPLs, thus, surfactants are applied to increase the aqueous solubility of chlorinated organics via micellar solubilization. However, a portion of surfactants can be partitioned into NAPL phases by forming reverse micelles within them. Consequently, lesser amounts of surfactants are available for the micellar solubilization of chlorinated organics in the aqueous phase. In this study, we investigated the partitioning behavior of non-ionic surfactants (Tween 20, Tween 40, Tween 80, and Triton X-100) between water and a NAPL phase consisting of tetrachloroethylene (PCE), trichloroethylene (TCE), or chloroform (CF). According to the experimental results, the partitioning of surfactants in the water-NAPL systems was found to follow linear or Langmuir-type isotherms. Regardless of type of surfactants, the partitioning loss of surfactants into NAPLs became greater with the more hydrophilic (i.e., the lower water-NAPL interfacial tension) chlorinated organics: PCE HLB) surfactant. Consistent with this postulation, the surfactant partitioning into PCE-NAPLs showed the similar trend. In case of TCE-NAPLs, however, the more hydrophobic Tween 40 was partitioned to a less extent than Tween 20. Therefore, the specific interaction of a NAPL-surfactant pair as well as their individual properties should be considered when selecting an effective surfactant for the remediation of a NAPL-contaminated site.

  12. Solute Transport from Aqueous Mixture through Supported Ionic Liquid Membrane by Pervaporation.

    Czech Academy of Sciences Publication Activity Database

    Izák, Pavel; Koekerling, M.; Kragl, U.

    2006-01-01

    Roč. 199, 1-3 (2006) , s. 96–98. ISSN 0011-9164. [Euromembrane 2006. Giardini, Naxos, 24.09.2006-28.09.2006] Institutional research plan: CEZ:AV0Z40720504 Keywords : supported ionic liquid membrane * pervaporation * 1,3-propanediol Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 0.917, year: 2006

  13. A spectroscopic and computational study of Al(III) complexes in sodium cryolite melts: Ionic composition in a wide range of cryolite ratios

    Science.gov (United States)

    Nazmutdinov, Renat R.; Zinkicheva, Tamara T.; Vassiliev, Sergey Yu.; Glukhov, Dmitri V.; Tsirlina, Galina A.; Probst, Michael

    2010-04-01

    The structure of sodium cryolite melts was studied using Raman spectroscopy and quantum chemical calculations performed at the density functional theory level. The existence of bridged forms in the melts was argued first from the analysis of experimental Raman spectra. In the quantum chemical modelling emphasis was put on the construction of potential energy surfaces describing the formation/dissociation of certain complex species. Effects of the ionic environment were found to play a crucial role in the energetics of model processes. The structure of the simplest possible polymeric forms involving two Al centres linked through F atoms ("dimers") was thoroughly investigated. The calculated equilibrium constants and model Raman spectra yield additional evidence in favour of the dimers. This agrees with a self-consistent analysis of a series of Raman spectra for a wide range of the melt composition.

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

    CERN Document Server

    Chevrot, Guillaume; Chaban, Vitaly V

    2015-01-01

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

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

    CERN Document Server

    de la Peña, Lisandro Hernández

    2009-01-01

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

  16. Aqueous biphasic system based on cholinium ionic liquids: extraction of biologically active phenolic acids

    OpenAIRE

    Branco, Sónia Isabel Pereira

    2014-01-01

    Phenolic acids are aromatic secondary plant metabolites, widely spread throughout the plant kingdom. Due to their biological and pharmacological properties, they have been playing an important role in phytotherapy and consequently techniques for their separation and purification are in need. This thesis aims at exploring new sustainable separation processes based on ionic liquids (ILs) in the extraction of biologically active phenolic acids. For that purpose, three phenolic acids with simi...

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

    Science.gov (United States)

    Qiu, Yinghua; Ma, Jian; Chen, Yunfei

    2016-05-17

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

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

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

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

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

    International Nuclear Information System (INIS)

    A series of experiments were performed to examine the capacity of H2O-fluids to concentrate and transport incompatible elements through peridotitic mantle and metamorphosed (eclogitic) ocean crust. Two naturally occurring rock compositions, trondhjemitic and basanitic, were used in experiments. The proton microprobe was used to determine the trace element concentrations in the solutes from H2O-fluids equilibrated at 900-1100 degree C, 2.0 GPa with water saturated melts of trondhjemitic and basanitic compositions. Partitioning data for H2O-fluids and silicate melts show that H2O-fluids equilibrated with mantle peridotites will not be strongly enriched in trace elements relative to their wallrocks, and thus they melts do not strongly concentrate alkaline earths Th and U, relative to high-field strength elements. 3 refs., 1 tab., 2 figs

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-12-31

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

  1. Estradiol Solubility in Aqueous Systems: Effect of Ionic Concentrations, pH, and Organic Solvents

    OpenAIRE

    Carter, John E. A.; Sluss, Patrick M.

    2013-01-01

    This study examined the effects of ionic strengths of NaCl (0.1, 0.3, and 1.0 M), pH (3, 7, and 11), and organic solvents (dichloromethane, diethyl ether, and methanol) on the extraction of estradiol at concentrations of 5.0 pg/mL in human serum. Methanol extracted almost 100% of the estradiol at a 5.0 pg/mL concentration, while ether and dichloromethane extracted only 73% or 70%, respectively, of the estradiol. The methanol extracted material was subjected to reverse phase high-performance l...

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

    International Nuclear Information System (INIS)

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

  3. Molecular dynamics study of the aqueous core of a reversed ionic micelle

    Science.gov (United States)

    Linse, Per

    1989-05-01

    The molecular structure and dynamics of a molecular electric double layer have been examined with the molecular dynamics simulation technique. A 50 ps trajectory from a simulation of a model system comprising 50 sodium ions and 1000 water molecules, spherically enclosed by a hydrophobic interface carrying 50 carboxylate groups, has been analyzed. The results show that the water structure is strongly distorted by the strong local fields and that the hydrophobic interface plays only a secondary role. The orientational polarization of the interfacial water molecules has been examined and compared with dielectric continuum theory. The dynamical results of this study show a reduced rate of translational as well as rotational motions of ionic hydrating water by a factor of 2-4 as compared to bulk water.

  4. Extraction of niobium anions from aqueous solutions by ionic flotation method

    International Nuclear Information System (INIS)

    A conceptual possibility of niobate (K2NbOF5 and K2NbF7) extraction from aqueous media using the ion flotation method is established. The optimum conditions, when using quaternary ammonium bases and amines as collectors, lie in the pH range 5.0-9.0. The interaction of niobates with cation-active surfactants can follow the ion-exchange mechanism. The presence of acid in a solution suppresses the interaction due to competitive effect of anions present and due to complexing of surfactant collectors

  5. Equilibrium partitioning of drug molecules between aqueous and amino acid ester-based ionic liquids

    International Nuclear Information System (INIS)

    Highlights: ► Partition coefficients of twelve drug molecules in ILs have been determined. ► The possible mechanism has been investigated from 13C NMR measurements. ► Hydrophobic π–π interaction is the main driving force for the partitioning of drug molecules. -- Abstract: In this work, a series of novel room temperature ionic liquids (ILs) have been synthesized with cheap, naturally α-amino acid ester as cations and bis(trifluoromethylsulfonyl)imide as anion. The glass transition temperature and thermal decomposition temperature of these ILs, partition coefficients of some coumarins and purine alkaloids between water and the amino acid ester-based ILs at T = 298.15 K, and Gibbs energy, enthalpy and entropy changes for the transfer of caffeine and 6,7-dihydroxycoumarin from water to [LeuC2][Tf2N] have been determined. It is shown that these ILs are highly effective materials for the extraction of drug compounds like coumarin, 4-hydroxycoumarin, 7-hydroxycoumarin, 3-aminocoumarin, coumarin-3-carboxylic acid, 6,7-dihydroxycoumarin, 6,7-dihydroxy-4-methylcoumarin, caffeine, theobromine, theophylline, inosine, and 2,6-diaminopurine. The partition process is driven by enthalpy term, and partition coefficients of the drug molecules increase with the increase of hydrophobicity of both the drug molecules and the ILs. Furthermore, the possible partition mechanism has been investigated from 13C NMR measurements

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

    Science.gov (United States)

    Rzayev, Javid

    2015-03-01

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

  7. Influence of alkyl chain on the thermodynamic properties of aqueous solutions of ionic liquids 1-alkyl-3-methylimidazolium bromide at different temperatures

    International Nuclear Information System (INIS)

    Osmotic coefficients φ, mean activity coefficients γ±, vapor pressure p data, and excess Gibbs free energies GE of aqueous solutions of three ionic liquids 1-propyl-3-methylimidazolium bromide [PMIm]Br, 1-pentyl-3-methylimidazolium bromide [PnMIm]Br, and 1-hexyl-3-methylimidazolium bromide [HMIm]Br were determined by the vapor pressure osmometry method at four temperatures (298.15 K to 328.15 K) in intervals 10 K. From the comparison of osmotic coefficients it follows that aqueous solution of [PMIm]Br shows a more pronounced deviation from Debye-Hueckel limiting law (DHLL) and vapor pressure depression more than the other studied ionic liquids which was interpreted in terms of hydrophobic interactions. The Pitzer-ion interaction and MNRTL electrolyte models satisfactorily correlate experimental osmotic coefficient data with good precision. The parameters of the Pitzer-ion interaction model are used to calculate the mean molal activity coefficients and excess Gibbs free energies

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

    Science.gov (United States)

    Umapathi, Reddicherla; Attri, Pankaj; Venkatesu, Pannuru

    2014-06-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-01-30

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

  10. Ionic Strength-Controlled Mn (Hydr)oxide Nanoparticle Nucleation on Quartz: Effect of Aqueous Mn(OH)2.

    Science.gov (United States)

    Jung, Haesung; Jun, Young-Shin

    2016-01-01

    The early formation of manganese (hydr)oxide nanoparticles at mineral-water interfaces is crucial in understanding how Mn oxides control the fate and transport of heavy metals and the cycling of nutrients. Using atomic force microscopy, we investigated the heterogeneous nucleation and growth of Mn (hydr)oxide under varied ionic strengths (IS; 1-100 mM NaNO3). Experimental conditions (i.e., 0.1 mM Mn(2+) (aq) concentration and pH 10.1) were chosen to be relevant to Mn remediation sites. We found that IS controls Mn(OH)2 (aq) formation, and that the controlled Mn(OH)2 (aq) formation can affect the system's saturation and subsequent Mn(OH)2 (s) and further Mn3O4 (s) nanoparticle formation. In 100 mM IS system, nucleated Mn (hydr)oxide particles had more coverage on the quartz substrate than those in 1 mM and 10 mM IS systems. This high IS also resulted in low supersaturation ratio and thus favor heterogeneous nucleation, having better structural matching between nucleating Mn (hydr)oxides and quartz. The unique information obtained in this work improves our understanding of Mn (hydr)oxide formation in natural as well as engineered aqueous environments, such as groundwater contaminated by natural leachate and acid mine drainage remediation. PMID:26588858

  11. Effect of mono-, di- and tri-ethanolammonium tetrafluoroborate protonic ionic liquids on vapour liquid equilibria of ethanol aqueous solution

    International Nuclear Information System (INIS)

    Vapour pressures were measured using a quasi-static ebulliometer for the binary mixture of (water + ethanol) containing one of three protonic ionic liquids (PIL), namely, mono-, di- or tri-ethanolammonium tetrafluoroborate, over the temperature range of (318.24 to 356.58) K at fixed PIL content of 0.30 in mass fraction. The vapour pressure data of the PIL-containing ternary systems were correlated using the NRTL equation with an overall root mean square deviation (RMSD) of 0.0092. The regressed NRTL parameters were used to predict the isobaric vapour liquid equilibria (VLE) for ternary systems (water + ethanol + PIL) at varying mass fraction of PIL and atmospheric pressure (101.3 kPa). It is shown that the effect of PILs on the VLE of the (water + ethanol) mixture follows the order: [HTEA][BF4] > [HDEA][BF4] > [HMEA][BF4]. In addition, the relative volatilities of ethanol to water for pseudo-binary systems (water + ethanol + PIL) were calculated. The results indicate that the PILs studied can enhance the relative volatility of ethanol to water and even break the azeotropic behaviour of ethanol aqueous solution when PIL content is increased to a specified content.

  12. Effect of mono-, di- and tri-ethanolammonium tetrafluoroborate protonic ionic liquids on vapour liquid equilibria of ethanol aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Shen Chong [State Key Laboratory of Chemical Resource Engineering and College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Ma Xiaoyan [College of Science, Beijing University of Chemical Technology, Beijing 100029 (China); Lu Yingzhou [State Key Laboratory of Chemical Resource Engineering and College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Li Chunxi, E-mail: Licx@mail.buct.edu.c [State Key Laboratory of Chemical Resource Engineering and College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029 (China)

    2011-03-15

    Vapour pressures were measured using a quasi-static ebulliometer for the binary mixture of (water + ethanol) containing one of three protonic ionic liquids (PIL), namely, mono-, di- or tri-ethanolammonium tetrafluoroborate, over the temperature range of (318.24 to 356.58) K at fixed PIL content of 0.30 in mass fraction. The vapour pressure data of the PIL-containing ternary systems were correlated using the NRTL equation with an overall root mean square deviation (RMSD) of 0.0092. The regressed NRTL parameters were used to predict the isobaric vapour liquid equilibria (VLE) for ternary systems (water + ethanol + PIL) at varying mass fraction of PIL and atmospheric pressure (101.3 kPa). It is shown that the effect of PILs on the VLE of the (water + ethanol) mixture follows the order: [HTEA][BF{sub 4}] > [HDEA][BF{sub 4}] > [HMEA][BF{sub 4}]. In addition, the relative volatilities of ethanol to water for pseudo-binary systems (water + ethanol + PIL) were calculated. The results indicate that the PILs studied can enhance the relative volatility of ethanol to water and even break the azeotropic behaviour of ethanol aqueous solution when PIL content is increased to a specified content.

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

    Science.gov (United States)

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

    2013-05-28

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

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

    OpenAIRE

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

    2016-01-01

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

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

    OpenAIRE

    Onghena, Bieke; Binnemans, Koen

    2015-01-01

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

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

    Science.gov (United States)

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

    2016-08-11

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

  17. Ionic liquid-anionic surfactant based aqueous two-phase extraction for determination of antibiotics in honey by high-performance liquid chromatography.

    Science.gov (United States)

    Yang, Xiao; Zhang, Shaohua; Yu, Wei; Liu, Zhongling; Lei, Lei; Li, Na; Zhang, Hanqi; Yu, Yong

    2014-06-01

    An ionic liquid-anionic surfactant based aqueous two-phase extraction was developed and applied for the extraction of tetracycline, oxytetracycline and chloramphenicol in honey. The honey sample was mixed with Na2EDTA aqueous solution. The sodium dodecyl sulfate, ionic liquid 1-octyl-3-methylimidazolium bromide and sodium chloride were added in the mixture. After the resulting mixture was ultrasonically shaken and centrifuged, the aqueous two phase system was formed and analytes were extracted into the upper phase. The parameters affecting the extraction efficiency, such as the volume of ionic liquid, the category and amount of salts, sample pH value, extraction time and temperature were investigated. The limits of detection of tetracycline, oxytetracycline and chloramphenicol were 5.8, 8.2 and 4.2 μg kg(-1), respectively. When the present method was applied to the analysis of real honey samples, the recoveries of analytes ranged from 85.5 to 110.9% and relative standard deviations were lower than 6.9%. PMID:24767438

  18. Cellulose aerogels prepared from an aqueous zinc chloride salt hydrate melt.

    Science.gov (United States)

    Schestakow, Maria; Karadagli, Ilknur; Ratke, Lorenz

    2016-02-10

    Monolithic cellulose aerogels are prepared using a salt hydrate melt based on cheap zinc chloride tetrahydrate (ZnCl2·4H2O) that can be washed out of the wet gel-body by using common solvents such as water, ethanol, isopropanol or acetone. Cellulose aerogels with concentrations of 1-5 wt.% cellulose were produced. These aerogels are characterized with respect to shrinkage, density and surface area as well as mechanical properties and micro-structure via SEM. Cellulose aerogels regenerated in acetone show a specific surface area of around 340 m(2)g(-1) being 60% higher than those regenerated in water. The onset of irreversible plastic deformation under compressive load is around 0.8 MPa for acetone-regenerated aerogels and thus a factor of two larger compared to ethanol regenerated ones. The Young's modulus depends almost linearly on the cellulose concentration which is observed for all regenerative fluids with the exception of water. The results achieved are presented in light of the polarity and ability of solvation of ZnCl2·4H2O in the regenerative fluids used. PMID:26686174

  19. Infrared spectroscopy of aqueous ionic salt mixtures at low concentrations: ion pairing in water.

    Science.gov (United States)

    Max, Jean-Joseph; Chapados, Camille

    2007-09-21

    The analysis by infrared spectroscopy of aqueous mixtures of NaI and CsCl was made in order to obtain information at the molecular level of the mixing of these two salts taken as model systems of strong electrolytes in water. In previous papers [J.-J. Max and C. Chapados, J. Chem. Phys. 115, 2664 (2001) and J.-J. Max et al., ibid. 126, 184507 (2007)] it was reported that a pure salt in water forms pairs of monoions to which are attached a fixed number of water molecules, giving solvated water species. Due to their interaction with the ion pairs, the solvated water molecules are strongly perturbed, modifying the IR water spectrum being monitored. After taking the IR spectrum of pure water, a small volume of NaI 2M was added and the IR spectrum taken. Then a small volume of CsCl 2M was added and a new IR spectrum taken. This procedure was repeated to obtain a series of 38 spectra in the 0.05M-0.83M concentration range. Factor analysis made on the series revealed the presence of three types of water: pure water and two salt solvated waters. The number of solvated water molecules on the two salts taken together is ten. Since NaI and CsCl have, respectively, 3.5 and 3.0 solvated water molecules, it was concluded that a reaction occurred in the solutions forming NaCl and CsI that have, respectively, five water molecules each for a total of ten. The analysis of the spectra of the orthogonal factors supports this attribution. These results provide additional proof of ion pairing in water. Furthermore, comparing the band displacements and intensity variations observed on the solvated water species to that of pure water indicates that the dielectric milieu surrounding the ion pairs is not constant. These results do not support the classical view of Debye-Huckel that considers that the ions are independent and the dielectric milieu constant. The present results give some in situ information on the reaction that goes on in "simple" electrolyte systems whose reactivity and

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-05-05

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

  1. Neptunium oxide precipitation kinetics in aqueous systems at elevated temperatures. Part I: Colloidal, temperature, inert atmosphere, and ionic strength measurements

    International Nuclear Information System (INIS)

    We evaluate the proposed NpO2+(aq)-NpO2(cr) reduction-precipitation system at elevated temperatures to obtain primary information on the effects of temperature, ionic strength, O2 and CO2. Experiments conducted on unfiltered solutions at 10-4 M NpO2+(aq), neutral pH, and 200 C indicated that solution colloids strongly affect precipitation kinetics. Subsequent experiments on filtered solutions at 200, 212, and 225 C showed consistent and distinctive temperature-dependent behavior at reaction times (le) 800 hours. At longer times, the 200 C experiments showed unexpected dissolution of neptunium solids, but experiments at 212 C and 225 C demonstrated quasi steady-state neptunium concentrations of 3 x 10-6 M and 6 x 10-6 M, respectively. Solids from a representative experiment analyzed by X-ray diffraction were consistent with NpO2(cr). A 200 C experiment with a NaCl concentration of 0.05 M showed a dramatic increase in the rate of neptunium loss. A 200 C experiment in an argon atmosphere resulted in nearly complete loss of aqueous neptunium. Previously proposed NpO2+(aq)-NpO2(cr) reduction-precipitation mechanisms in the literature specified a 1:1 ratio of neptunium loss and H+ production in solution over time. However, all experiments demonstrated ratios of approximately 0.4 to 0.5. Carbonate equilibria can account for only about 40% of this discrepancy, leaving an unexpected deficit in H+ production that suggests that additional chemical processes are occurring.

  2. Nicotine aqueous solutions: pH-measurements and salting-out effects - analysis of the effective Gibbs energies of hydration and ionic strengths of the solutions

    Directory of Open Access Journals (Sweden)

    Grozdanić Nikola D.

    2014-01-01

    Full Text Available This work is a continuation of our previous studies on the phase demixing - salting-out effects - in aqueous nicotine solutions. Thus, pH measurements were carried out allowing a brief analysis of the existing hydrogen bond interactions. Salting-out effects - the related experimental cloud point shifts - provoked by the addition of two inorganic salts, potassium nitrate and sodium sulfate, which were not studied so far, were determined. Analysis of the current and our previously reported salting-out/or salting-in phenomena in nicotine aqueous solutions was performed. In this respect, five studied salts were included: four inorganic salts (sodium chloride, potassium nitrate, sodium sulfate and sodium phosphate (Na3PO4 and ionic liquid 1-ethyl-3-methylimidazolium ethyl sulfate ([C2mim][EtSO4] or ECOENG212®. Based on the pH measurements the effective Gibbs energies of hydration and ionic strengths of the respective ternary solutions were calculated and plotted against the related cloud-point shifts caused by the addition of the salts. For the studied salts, the results and diagram obtained within this work may be used to predict the cloud-points shifts, based on the related quantities of the salts added and/or the molar Gibbs energies of hydration and/or ionic strengths requested in each case. [Projekat Ministarstva nauke Republike Srbije, br. 172063

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-02-15

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

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

    OpenAIRE

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

    2009-01-01

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

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

    International Nuclear Information System (INIS)

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

  6. Extraction of natural radionuclides from aqueous solutions by novel maltolate-based task-specific ionic liquids

    International Nuclear Information System (INIS)

    Two novel maltol-based ionic liquids, namely [A336][Mal] and [C101][Mal], were synthesized as potential extracting agents for radionuclides from water. These two room temperature task-specific ionic liquids could be easily prepared by anion metathesis starting from commercially available materials. The isolated compounds were characterized by standard analytical methods. Their application as extraction agent for Unat., 234Th, 210Pb, 210Bi, 210Po and 226Ra was elucidated by liquid-liquid extraction and scintillation counting. Uranium was totally extracted by both ionic liquids over a broad pH range (2-8), while the other radionuclides were removed with differing efficacies depending on the respective pH value. (author)

  7. Ammonium ionic liquid as modulator of the critical micelle concentration of ammonium surfactant at aqueous solution: conductimetric and dynamic light scattering (DLS) studies.

    Science.gov (United States)

    Sifaoui, Hocine; Lugowska, Katarzyna; Domańska, Urszula; Modaressi, Ali; Rogalski, Marek

    2007-10-15

    We report measurements of self aggregation in aqueous solution of an ionic liquid (IL), didecyl-dimethylammonium nitrate ([DDA][NO(3)]) and a surfactant hexadecyl-trimethylammonium bromide (CTAB) and of mixtures of these two salts. The electrical conductivity and dynamic light scattering (DLS) measurements were used for the characterization of the aggregation process. The conductivity measurements were performed at three temperatures. The critical micelle concentration (CMC) was determined at different temperatures and at different ratio of two salts. The effect of IL on the micellization of CTAB has been discussed. Our results suggest that organized structures formed by CTAB and [DDA][NO(3)] self assembly in domains of several hundred nanometers size. The micellar solubility of the salicylic acid in mixed salt aqueous solutions was determined to probe the physical properties of these assemblies. We have observed, that the micellar solubility enhancement was only slightly influenced by the nature of micelles present in aqueous solution. This proves that salicylic acid solubilization is enthalpy driven. PMID:17618639

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

    International Nuclear Information System (INIS)

    The volumetric properties of seven {water + ionic liquid} binary mixtures have been studied as a function of temperature from (293 to 343) K. The phase behaviour of the systems was first investigated using a nephelometric method and excess molar volumes were calculated from densities measured using an Anton Paar densimeter and fitted using a Redlich-Kister type equation. Two ionic liquids fully miscible with water (1-butyl-3-methylimidazolium tetrafluoroborate ([C1C4Im][BF4]) and 1-ethyl-3-methylimidazolium ethylsulfate ([C1C2Im][EtSO4])) and five ionic liquids only partially miscible with water (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C1C2Im][NTf2]), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C1C4Im][NTf2]), 1-butyl-3-methylimidazolium hexafluorophosphate ([C1C4Im][PF6]), 1-butyl-3-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([C1C4Pyrro][NTf2]), and butyltrimethylammonium bis(trifluoromethylsulfonyl)imide ([N4111][NTf2])) were chosen. Small excess volumes (less than 0.5 cm3 . mol-1 at 298 K) are obtained compared with the molar volumes of the pure components (less than 0.3% of the molar volume of the pure ionic liquid). For all the considered systems, except for {[C1C2Im][EtSO4] + water}, positive excess molar volumes were calculated. Finally, an increase of the non-ideality character is observed for all the systems as temperature increases.

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

    Energy Technology Data Exchange (ETDEWEB)

    Wang Silu [QUILL Research Center, School of Chemistry, Queen' s University of Belfast (United Kingdom); Jacquemin, Johan [QUILL Research Center, School of Chemistry, Queen' s University of Belfast (United Kingdom); Thermodynamique et Interactions Moleculaires, FRE 3099, Universite Blaise Pascal Clermont-Ferrand/CNRS, 24 avenue des Landais, 63177 Aubiere Cedex (France); Husson, Pascale [Thermodynamique et Interactions Moleculaires, FRE 3099, Universite Blaise Pascal Clermont-Ferrand/CNRS, 24 avenue des Landais, 63177 Aubiere Cedex (France)], E-mail: pascale.husson@univ-bpclermont.fr; Hardacre, Christopher [QUILL Research Center, School of Chemistry, Queen' s University of Belfast (United Kingdom); Costa Gomes, Margarida F. [Thermodynamique et Interactions Moleculaires, FRE 3099, Universite Blaise Pascal Clermont-Ferrand/CNRS, 24 avenue des Landais, 63177 Aubiere Cedex (France)

    2009-11-15

    The volumetric properties of seven {l_brace}water + ionic liquid{r_brace} binary mixtures have been studied as a function of temperature from (293 to 343) K. The phase behaviour of the systems was first investigated using a nephelometric method and excess molar volumes were calculated from densities measured using an Anton Paar densimeter and fitted using a Redlich-Kister type equation. Two ionic liquids fully miscible with water (1-butyl-3-methylimidazolium tetrafluoroborate ([C{sub 1}C{sub 4}Im][BF{sub 4}]) and 1-ethyl-3-methylimidazolium ethylsulfate ([C{sub 1}C{sub 2}Im][EtSO{sub 4}])) and five ionic liquids only partially miscible with water (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C{sub 1}C{sub 2}Im][NTf{sub 2}]), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C{sub 1}C{sub 4}Im][NTf{sub 2}]), 1-butyl-3-methylimidazolium hexafluorophosphate ([C{sub 1}C{sub 4}Im][PF{sub 6}]), 1-butyl-3-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([C{sub 1}C{sub 4}Pyrro][NTf{sub 2}]), and butyltrimethylammonium bis(trifluoromethylsulfonyl)imide ([N{sub 4111}][NTf{sub 2}])) were chosen. Small excess volumes (less than 0.5 cm{sup 3} . mol{sup -1} at 298 K) are obtained compared with the molar volumes of the pure components (less than 0.3% of the molar volume of the pure ionic liquid). For all the considered systems, except for {l_brace}[C{sub 1}C{sub 2}Im][EtSO{sub 4}] + water{r_brace}, positive excess molar volumes were calculated. Finally, an increase of the non-ideality character is observed for all the systems as temperature increases.

  10. Micro-electrodeposition in the presence of ionic liquid for the preconcentration of trace amounts of Fe, Co, Ni and Zn from aqueous samples

    International Nuclear Information System (INIS)

    The paper presents the preconcentration of trace elements via electrodeposition onto a (micro)aluminum cathode in the presence of ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6] as a supporting electrolyte. The advantages of the proposed method include very simple instrumentation for the preconcentration of trace elements and low-cost reagents. The experiment showed that the use of ionic liquid in the electrodeposition process significantly improves sensitivity, recovery and detection limits for the determination of trace amounts of iron, cobalt, nickel and zinc. The preconcentrated metals were determined using X-ray fluorescence spectrometry. The optimum parameters for electrodeposition such as pH, the volume of the analyzed solution, the voltage and the deposition time were studied. Under the optimized conditions, the detection limits were 5, 2, 3 and 6 μg L−1 for iron, cobalt, nickel and zinc, respectively. The precision and recovery of the method were in the range of 3–5.5%, and 92–103%, respectively. The calibration was performed using aqueous standards of Fe(III), Co(II), Ni(II) and Zn(II) in the range 0.01–0.25 mg L−1. The method was applied successfully in water analysis. - Highlights: ► A novel method of micro sample preparation for XRF analysis is proposed. ► Electrodeposition is performed using microcathode. ► A novel modification of electrodeposition method is using ionic liquid. The method can be combined with many techniques for multielement trace analysis

  11. Solubility and modeling acid-base properties of adrenaline in NaCl aqueous solutions at different ionic strengths and temperatures.

    Science.gov (United States)

    Bretti, Clemente; Cigala, Rosalia Maria; Crea, Francesco; De Stefano, Concetta; Vianelli, Giuseppina

    2015-10-12

    Solubility and acid-base properties of adrenaline were studied in NaCl aqueous solutions at different ionic strengths (0solubility of the ligand was calculated from simple mass balance equations, by using the free hydrogen concentration and the protonation constants of the ligand determined in the same experimental conditions of the solubility measurements. The salting-In or Out parameters and the activity coefficient of the neutral species were calculated by means of the Setschenow equation. The dependence of the protonation constants on the ionic strength was modeled by means of the Debye-Hückel type equation and of the SIT (Specific ion Interaction Theory) approach. The specific interaction parameters of the ion pairs were also reported. For the protonation constants, the following thermodynamic values at infinite dilution were obtained: T=298.15 K, logK1(H0)=10.674±0.018 and logK2(H0)=8.954±0.022; T=310.15K, logK1(H0)=10.355±0.018 and logK2(H0)=8.749±0.030. PMID:26122929

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

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

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

  13. Separation, concentration and determination of chloramphenicol in environment and food using an ionic liquid/salt aqueous two-phase flotation system coupled with high-performance liquid chromatography.

    Science.gov (United States)

    Han, Juan; Wang, Yun; Yu, Cuilan; Li, Chunxiang; Yan, Yongsheng; Liu, Yan; Wang, Liang

    2011-01-31

    Ionic liquid-salt aqueous two-phase flotation (ILATPF) is a novel, green, non-toxic and sensitive samples pretreatment technique. ILATPF coupled with high-performance liquid chromatography (HPLC) was developed for the analysis of chloramphenicol, which combines ionic liquid aqueous two-phase system (ILATPS) based on imidazolium ionic liquid (1-butyl-3-methylimidazolium chloride, [C(4)mim]Cl) and inorganic salt (K(2)HPO(4)) with solvent sublation. In ILATPF systems, phase behaviors of the ILATPF were studied for different types of ionic liquids and salts. The sublation efficiency of chloramphenicol in [C(4)mim]Cl-K(2)HPO(4) ILATPF was influenced by the types of salts, concentration of K(2)HPO(4) in aqueous solution, solution pH, nitrogen flow rate, sublation time and the amount of [C(4)mim]Cl. Under the optimum conditions, the average sublation efficiency is up to 98.5%. The mechanism of ILATPF contains two principal processes. One is the mechanism of IL-salt ILATPS formation, the other is solvent sublation. This method was practical when applied to the analysis of chloramphenicol in lake water, feed water, milk, and honey samples with the linear range of 0.5-500 ng mL(-1). The method yielded limit of detection (LOD) of 0.1 ng mL(-1) and limit of quantification (LOQ) of 0.3 ng mL(-1). The recovery of CAP was 97.1-101.9% from aqueous samples of environmental and food samples by the proposed method. Compared with liquid-liquid extraction, solvent sublation and ionic liquid aqueous two-phase extraction, ILATPF can not only separate and concentrate chloramphenicol with high sublation efficiency, but also efficiently reduce the wastage of IL. This novel technique is much simpler and more environmentally friendly and is suggested to have important applications for the concentration and separation of other small biomolecules. PMID:21168562

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

    Science.gov (United States)

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

    2015-07-28

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

  15. Self-aggregation of ionic liquid 1-butyl-2,3-dimethylimidazolium tetrafluoroborate [C4mmim][BF4] in aqueous media: A conductometric, volumetric and spectroscopic study

    International Nuclear Information System (INIS)

    Highlights: • Self-aggregation behaviour of [C4mmim][BF4] has been studied using various techniques. • Thermodynamic parameters showing aggregation is an entropy-driven process. • Volumetric analysis indicates aggregation is influenced by solute–solvent interactions. • 1H NMR revealed formation of loosely bound aggregates in the system. - Abstract: Aggregation behaviour of ionic liquid (IL), 1-butyl-2,3-dimethylimidazolium tetrafluoroborate, [C4mmim][BF4] in aqueous media has been studied by electrical conductivity, density and speed of sound measurements across temperature range (288.15–308.15) K. The critical aggregation concentration (cac), the standard Gibb’s free energy of aggregation, ΔG°agg, adiabatic compressibility, βS and changes in the adiabatic compressibility upon aggregation, ΔβS,agg for the IL in aqueous solution have been derived from the experimental data. Further to get the deeper insights into the aggregation process spectroscopic study using 1H NMR measurements have been carried out. The aggregation behaviour observed from conductance and volumetric approaches has been found to be in good agreement with each other. NMR study revealed the formation of loosely bound ion associates as aggregates in the system upon aggregation

  16. Salt-effects in aqueous surface-active ionic liquid 1-dodecyl-3-methylimidazolium bromide solutions: Volumetric and compressibility property changes and critical aggregation concentration shifts

    International Nuclear Information System (INIS)

    Graphical abstract: Plot of ϕV against mIL, for solutions of [C12mim]Br in water (solid lines) and in aqueous solutions of 0.035 mol · kg−1 NaCl (dotted lines) at: ○ and ●, T = 288.15 K; △ and ▴,T = 293.15 K; □ and ■, T = 298.15 K. - Highlights: • Salt effect on the aggregation of [C12mim]Br in aqueous solutions were studied. • The effect of 6 chloride electrolytes and 5 sodium electrolytes were investigated. • Investigated electrolytes have salting-out effect on the aggregation of [C12mim]Br. • Changes in the volumes and compressibilities upon micellization were derived. - Abstract: Systematic studies on the volumetric and compressibility properties of aqueous solutions of model surface-active ionic liquid 1-dodecyl-3-methylimidazolium bromide ([C12mim]Br) are performed in the absence and presence of a large series of electrolytes in order to achieve a deeper understanding about the molecular mechanism behind the specific salt effect on the aggregation behavior of [C12mim]Br in aqueous solution. For this purpose, 6 chloride electrolytes (NaCl, KCl, NH4Cl, (CH3)4NCl, MgCl2 and FeCl3) and 5 sodium electrolytes (NaCl, NaNO3, Na2CO3, Na2SO4, and Na3Cit.) were used in order to individualize the effect of the anion and the cation. The values of the critical aggregation concentration (CAC) were obtained and it was found that all the investigated electrolytes have salting-out effect on the aggregation of [C12mim]Br in aqueous solutions, leading to significant downward shifts of the CAC. The magnitude of the shifts depends on the water-structuring nature of the electrolyte and follows the Hofmeister series. Changes in the apparent molar volumes and isentropic compressibilities upon micellization were derived using a pseudophase-transition approach and the infinite dilution apparent molar properties of the monomer and micellar form of [C12mim]Br were determined

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

    OpenAIRE

    Youichi Takata; Hiroaki Tagashira; Atsushi Hyono; Hiroyuki Ohshima

    2010-01-01

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

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

    OpenAIRE

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

    2016-01-01

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

  19. Triton X-100 as a complete liquid scintillation cocktail for counting aqueous solutions and ionic nutrient salts

    International Nuclear Information System (INIS)

    Triton X-100, used alone, was found to act as a complete liquid scintillation cocktail. Triton X-100 acted as a scintillator and the effect was not due to Cerenkov radiation. A variety of other commercially available surfactants also acted as scintillators, but with different levels of efficiency. Triton X-100/water combinations were suitable for counting aqueous solutions of 33P and 86Rb and the count rate was stable over extended periods of time. Triton X-100/toluene combinations also yielded high counting efficiencies. Triton X-100 was more sensitive to quenching than standard cocktails containing fluors. (author)

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

    Science.gov (United States)

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

    2013-10-01

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

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

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    Angeliki Lekatou

    2016-02-01

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

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

    Directory of Open Access Journals (Sweden)

    Youichi Takata

    2010-04-01

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

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

    Science.gov (United States)

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

    2016-02-20

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

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

    Directory of Open Access Journals (Sweden)

    Zhijian Tan

    2016-03-01

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

  6. Ionic liquid directed syntheses of water-stable Eu- and Tb-organic-frameworks for aqueous-phase detection of nitroaromatic explosives.

    Science.gov (United States)

    Qin, Jian-Hua; Ma, Bing; Liu, Xiao-Fei; Lu, Hong-Lin; Dong, Xi-Yan; Zang, Shuang-Quan; Hou, Hongwei

    2015-09-01

    Reactions of lanthanide nitrate, 1,3,5-benzenetrisbenzoic acid (H3BTB) and [RMI]Br ionic liquids (RMI = 1-alkyl-3-methylimidazolium; R = ethyl, propyl, butyl, amyl, or hexyl), gave rise to two novel lanthanide metal-organic frameworks (Ln-MOFs) [Ln(BTB)H2O], where Ln = Eu , Tb . In addition to helping solubilise the starting materials under the reaction conditions there is evidence that [RMI]Br itself can play a structure directing role and is intimately involved in template ordering in [Ln(BTB)H2O], even though neither the [RMI](+) cation nor the Br(-) anion is occluded into the ultimate structure. and are isostructural and consist of infinite rod-shaped lanthanide-carboxylate building units which are further bridged by trigonal-planar BTB ligands to give noninterpenetrated open 3D frameworks featuring a (6,6)-connected topology with the point symbol (4(4)·6(7)·8(4))(4(8)·6(7)). Importantly, the strong emission of and dispersed in water prompted us to explore their application for detection of different nitroaromatics in an aquatic system. and show similar selectivity and sensitivity towards the presence of trace amounts of nitroaromatic analytes in the aqueous phase, showing potential as explosive sensors. PMID:26174185

  7. Structural characterization of zinc(II) chloride in aqueous solution and in the protic ionic liquid ethyl ammonium nitrate by x-ray absorption spectroscopy

    Science.gov (United States)

    D'Angelo, Paola; Zitolo, Andrea; Ceccacci, Francesca; Caminiti, Ruggero; Aquilanti, Giuliana

    2011-10-01

    Extended x-ray absorption fine structure (EXAFS) spectroscopy has been used to investigate the species and structures existing in a series of ZnCl2-H2O-NaCl solutions with different chloride/zinc ratios and in a solution of ZnCl2 in the protic ionic liquid ethyl ammonium nitrate (EAN). The average coordination numbers and distances of zinc species were determined from the analysis of the EXAFS data. In aqueous solution the number of chloride ions tightly bounded to Zn2+ is significantly related to the chloride/zinc ratio, and no inner complex formation between Zn2+ and Cl- ions has been detected for low ZnCl2 concentration (0.1 and 0.2 M). Conversely, in the same concentration range (0.13 M) the ZnCl2 species do not dissociate in EAN and the Zn2+ first coordination shell has two chloride ions and is completed by two oxygen atoms of the nitrate anion. The results of this investigation show that notwithstanding the existence of similar characteristics between EAN and water, the solvation properties of the two solvents are markedly different.

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

    Science.gov (United States)

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

    2016-04-01

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

  9. Comb-like ionic complexes of hyaluronic acid with alkyltrimethylammonium surfactants

    OpenAIRE

    Tolentino, Ainhoa; Alla Bedahnane, Abdelilah; Martínez de Ilarduya Sáez de Asteasu, Domingo Antxon; Muñoz Guerra, Sebastián

    2013-01-01

    Stoichiometric complexes of hyaluronic acid with alkyltrimethylammonium surfactants bearing octadecyl, eicosyl and docosyl groups were prepared by ionic coupling in aqueous solution. The complexes were non soluble in water but soluble in organic solvents. In the solid state they self-assembled in a biphasic layered structure with the alkyl side chains forming a separate phase that melted in the 50–60 °C range. They were stable to heating up to above 200 °C.

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

    OpenAIRE

    2014-01-01

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

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

    International Nuclear Information System (INIS)

    A detailed investigation on the molecular dynamics of ionic deep eutectic solvents (acetamide + lithium nitrate/sodium thiocyanate) is reported. The study was carried out employing dielectric relaxation spectroscopy covering seven decades in frequency (10−1-106 Hz) and in a wide temperature range from 373 K down to 173 K, accessing the dynamic observables both in liquid and glassy state. The dielectric response of the ionic system has been presented in the dynamic window of modulus formalism to understand the conductivity relaxation and its possible connection to the origin of localized motion. Two secondary relaxation processes appear below glass transition temperature. Our findings provide suitable interpretation on the nature of secondary Johari-Goldstein process describing the ion translation and orientation of dipoles in a combined approach using Ngai’s coupling model. A nearly constant loss feature is witnessed at shorter times/lower temperatures. We also discuss the ac conductivity scaling behavior using Summerfield approach and random free energy barrier model which establish the time-temperature superposition principle. These experimental observations have fundamental importance on theoretical elucidation of the conductivity relaxation and glass transition phenomena in molten ionic conductors

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-05-14

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

  13. Spectroscopic studies of the ionic liquid during the electrodeposition of Al–Ti alloy in 1-ethyl-3-methylimidazolium chloride melt

    International Nuclear Information System (INIS)

    Graphical abstract: Al3Ti alloy in EmimCl forms via an Al–Ti complex which has been established by characterizing the electrolyte using FTIR, UV–vis and NMR techniques. Highlights: ► We show the possibility of electrodepositing Al–Ti alloy using ionic liquid electrolyte. ► The reaction mechanism was evaluated using UV–visible spectroscopy, FTIR and NMR studies. ► From the spectroscopic studies the formation of a Al–Ti complex with ionic liquids was evident. - Abstract: A new approach for the formation of Al–Ti alloy in 1-ethyl-3-methylimidazolium chloride (EmimCl) was investigated. The dissolution of titanium electrodes in presence of EmimCl:AlCl3 was performed at various potentials to understand the effect of voltage on the reaction rate. It was observed that at low potentials, the presence of titanium hinders the reaction and diminishes the formation of aluminum and aluminum–titanium alloy at the cathode. However, at higher potentials there was substantial formation of Al3Ti alloy. To understand the reaction mechanism during the electrolysis, the electrolyte was characterized using Fourier transform infrared spectroscopy (FTIR), UV–visible spectroscopy (UV–vis) and nuclear magnetic resonance (NMR) techniques. The material on the cathode was characterized using scanning electron microscope (SEM) and Energy dispersive X-ray (EDX) techniques. From the above analysis it was found that titanium forms a complex with aluminum and also assists in formation of AlCl4− phase in the acidic ionic liquid.

  14. Growth kinetics of step edges on celestite (0 0 1) surfaces as a function of temperature, saturation state, ionic strength, and aqueous strontium:sulfate ratio: An in-situ atomic force microscopy study

    Science.gov (United States)

    Bracco, Jacquelyn N.; Gooijer, Yiscka; Higgins, Steven R.

    2016-02-01

    Step velocities on the celestite (0 0 1) surface have been measured as a function of temperature (23-45 °C), saturation state (S = 1.1-2.2), ionic strength (I = 0.01, 0.06, and 0.1 M), and aqueous strontium:sulfate ratio (r = 0.01-100) using atomic force microscopy (AFM). Celestite growth hillocks were flanked by [0 1 0]-aligned step edges, which are polar, and step edges vicinal to , which are non-polar. [0 1 0] step velocities increased with temperature and saturation state, however step velocities did not vary significantly with ionic strength. Step velocities were non-linear with saturation state, suggesting a change in mechanism at high S as compared with low S. At constant S, the step velocities were maximized at r = 1 and decreased significantly at extreme r, demonstrating the governing role of solute stoichiometry. We successfully fit the step velocity data as a function of r using the Stack and Grantham (2010) nucleation and propagation model. Based on the results as a function of ionic strength and r, the mechanism at low S is likely ion-by-ion attachment to the step with an activation energy of 75 (±10) kJ mol-1. At high S the mechanism is a combination of the one at low S and possibly attachment of a neutral species such as an ion pair with an activation energy of 43 (±9) kJ mol-1.

  15. Removal of reactive red-120 and 4-(2-pyridylazo) resorcinol from aqueous samples by Fe{sub 3}O{sub 4} magnetic nanoparticles using ionic liquid as modifier

    Energy Technology Data Exchange (ETDEWEB)

    Absalan, Ghodratollah, E-mail: gubsulun@yahoo.com [Professor Masoumi Laboratory, Department of Chemistry, College of Science, Shiraz University, Hafeziyeh, Fars, 71454 Shiraz (Iran, Islamic Republic of); Asadi, Mozaffar; Kamran, Sedigheh; Sheikhian, Leila [Professor Masoumi Laboratory, Department of Chemistry, College of Science, Shiraz University, Hafeziyeh, Fars, 71454 Shiraz (Iran, Islamic Republic of); Goltz, Douglas M. [Department of Chemistry, University of Winnipeg, Winnipeg, MB, R3B 2E9 Canada (Canada)

    2011-08-30

    Highlights: {yields} Ionic liquids modify the dye-adsorption characteristics of magnetic nanoparticles. {yields} Modified nanoparticles improved the sensitivity of dye measurements. {yields} Water-solubility is an important factor for choosing an ionic liquid as a modifier for nanoparticles. - Abstract: The nanoparticles of Fe{sub 3}O{sub 4} as well as the binary nanoparticles of ionic liquid and Fe{sub 3}O{sub 4} (IL-Fe{sub 3}O{sub 4}) were synthesized for removal of reactive red 120 (RR-120) and 4-(2-pyridylazo) resorcinol (PAR) as model azo dyes from aqueous solutions. The mean size and the surface morphology of the nanoparticles were characterized by TEM, DLS, XRD, FTIR and TGA techniques. Adsorption of RR-120 and PAR was studied in a batch reactor at different experimental conditions such as nanoparticle dosage, dye concentration, pH of the solution, ionic strength, and contact time. Experimental results indicated that the IL-Fe{sub 3}O{sub 4} nanoparticles had removed more than 98% of both dyes under the optimum operational conditions of a dosage of 60 mg, a pH of 2.5, and a contact time of 2 min when initial dyes concentrations of 10-200 mg L{sup -1} were used. The maximum adsorption capacity of IL-Fe{sub 3}O{sub 4} was 166.67 and 49.26 mg g{sup -1} for RR-120 and PAR, respectively. The isotherm experiments revealed that the Langmuir model attained better fits to the equilibrium data than the Freundlich model. The Langmuir adsorption constants were 5.99 and 3.62 L mg{sup -1} for adsorptions of RR-120 and PAR, respectively. Both adsorption processes were endothermic and dyes could be desorbed from IL-Fe{sub 3}O{sub 4} by using a mixed NaCl-acetone solution and adsorbent was reusable.

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

    Directory of Open Access Journals (Sweden)

    Fengli Chen

    2014-01-01

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

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

    Czech Academy of Sciences Publication Activity Database

    Lokajová, Jana; Railila, A.; King, A. W. T.; Wiedmer, S. K.

    2013-01-01

    Roč. 1308, Sep 20 (2013), s. 144-151. ISSN 0021-9673 R&D Projects: GA TA ČR TA02010760 Institutional support: RVO:61388963 Keywords : critical micelle concentration * electrokinetic chromatography * distribution constant * PeakMaster * phosphonium ionic liquid Subject RIV: CC - Organic Chemistry Impact factor: 4.258, year: 2013

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

    Institute of Scientific and Technical Information of China (English)

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

    2015-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    谢秀娟; 张振新

    2011-01-01

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

  20. Fullerol ionic fluids

    KAUST Repository

    Fernandes, Nikhil

    2010-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    关卫省; 黎文娟; 韩娟

    2012-01-01

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

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

    International Nuclear Information System (INIS)

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

  3. Membrane separation of ionic liquid solutions

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-09-01

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

  4. Hydrogen production from glucose in ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-01

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

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

    Institute of Scientific and Technical Information of China (English)

    郑惠榕; 林棋

    2012-01-01

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

  6. Thermodynamic Properties of Caprolactam Ionic Liquids

    Institute of Scientific and Technical Information of China (English)

    JIANG Lu; BAI Liguang; ZHU Jiqin; CHEN Biaohua

    2013-01-01

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

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

    Directory of Open Access Journals (Sweden)

    K.Vijaya Bhaskar

    2012-09-01

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

  8. Engineering ionic liquid-tolerant cellulases for biofuels production.

    Science.gov (United States)

    Wolski, Paul W; Dana, Craig M; Clark, Douglas S; Blanch, Harvey W

    2016-04-01

    Dissolution of lignocellulosic biomass in certain ionic liquids (ILs) can provide an effective pretreatment prior to enzymatic saccharification of cellulose for biofuels production. Toward the goal of combining pretreatment and enzymatic hydrolysis, we evolved enzyme variants of Talaromyces emersonii Cel7A to be more active and stable than wild-type T. emersonii Cel7A or Trichoderma reesei Cel7A in aqueous-IL solutions (up to 43% (w/w) 1,3-dimethylimdazolium dimethylphosphate and 20% (w/w) 1-ethyl-3-methylimidazolium acetate). In general, greater enzyme stability in buffer at elevated temperature corresponded to greater stability in aqueous-ILs. Post-translational modification of the N-terminal glutamine residue to pyroglutamate via glutaminyl cyclase enhanced the stability of T. emersonii Cel7A and variants. Differential scanning calorimetry revealed an increase in melting temperature of 1.9-3.9°C for the variant 1M10 over the wild-type T. emersonii Cel7A in aqueous buffer and in an IL-aqueous mixture. We observed this increase both with and without glutaminyl cyclase treatment of the enzymes. PMID:26819239

  9. A peroxotungstate-ionic liquid brush assembly: an efficient and reusable catalyst for selectively oxidizing sulfides with aqueous H2O2 solution in neat water

    International Nuclear Information System (INIS)

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

  10. Spring thaw ionic pulses boost nutrient availability and microbial growth in entombed Antarctic Dry Valley cryoconite holes.

    Science.gov (United States)

    Telling, Jon; Anesio, Alexandre M; Tranter, Martyn; Fountain, Andrew G; Nylen, Thomas; Hawkings, Jon; Singh, Virendra B; Kaur, Preeti; Musilova, Michaela; Wadham, Jemma L

    2014-01-01

    The seasonal melting of ice entombed cryoconite holes on McMurdo Dry Valley glaciers provides oases for life in the harsh environmental conditions of the polar desert where surface air temperatures only occasionally exceed 0°C during the Austral summer. Here we follow temporal changes in cryoconite hole biogeochemistry on Canada Glacier from fully frozen conditions through the initial stages of spring thaw toward fully melted holes. The cryoconite holes had a mean isolation age from the glacial drainage system of 3.4 years, with an increasing mass of aqueous nutrients (dissolved organic carbon, total nitrogen, total phosphorus) with longer isolation age. During the initial melt there was a mean nine times enrichment in dissolved chloride relative to mean concentrations of the initial frozen holes indicative of an ionic pulse, with similar mean nine times enrichments in nitrite, ammonium, and dissolved organic matter. Nitrate was enriched twelve times and dissolved organic nitrogen six times, suggesting net nitrification, while lower enrichments for dissolved organic phosphorus and phosphate were consistent with net microbial phosphorus uptake. Rates of bacterial production were significantly elevated during the ionic pulse, likely due to the increased nutrient availability. There was no concomitant increase in photosynthesis rates, with a net depletion of dissolved inorganic carbon suggesting inorganic carbon limitation. Potential nitrogen fixation was detected in fully melted holes where it could be an important source of nitrogen to support microbial growth, but not during the ionic pulse where nitrogen availability was higher. This study demonstrates that ionic pulses significantly alter the timing and magnitude of microbial activity within entombed cryoconite holes, and adds credence to hypotheses that ionic enrichments during freeze-thaw can elevate rates of microbial growth and activity in other icy habitats, such as ice veins and subglacial regelation zones

  11. Linear relation between the ionic radii of alkali and halogen ions in the crystal (based on the golden ration) and in aqueous solutions

    Czech Academy of Sciences Publication Activity Database

    Heyrovská, Rajalakshmi

    Brno: Přírodovědecká fakulta Masarykovy univerzity, 2006 - (Trnková, L.; Janderka, P.; Kizek, R.). s. 38-39 ISBN 80-210-3943-4. [Pracovní setkání fyzikálních chemiků a elektrochemiků /6./. 07.02.2006, Brno] R&D Projects: GA MPO 1H-PK/42 Institutional research plan: CEZ:AV0Z40400503 Keywords : golden ratio * aqueous solutions * physical chemistry Subject RIV: CF - Physical ; Theoretical Chemistry

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

    Institute of Scientific and Technical Information of China (English)

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

    2015-01-01

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

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

    Science.gov (United States)

    Nanda, Raju; Kumar, Anil

    2015-01-29

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

  14. Functional ionic liquids

    International Nuclear Information System (INIS)

    In the thesis at hand, new functional ionic liquids were investigated. Main focus was attended to their structure property relations and the structural features leading to a decrease of the melting point. New compounds of the type 1-butyl-3-methylimidazolium tris(N,Ndialkyldithiocarbamato) uranylate with variously substituated dithiocarbamato ligands were synthesized and characterized. Ligands with asymmetrical substitution pattern proved to be most suitable for ionic liquid formation. The single-crystal X-ray structures revealed the interactions in the solid state. Here, the first spectroscopic investigation of the U-S bond in sulfur donated uranyl complexes, up to now only observed in single-crystal X-ray structures, is presented, and the participation of the uranium f-orbitals is shown by theoretical calculations. Electrochemical investigations showed the accessibility of the respective UVO2+ compounds. As well, ionic liquids with [FeCl4]- and [Cl3FeOFeCl3]2- as anion were synthesized. Both of these anions contain high-spin Fe(III) centres in distorted tetrahedral environment, but exhibit different magnetic behaviour. The tetrachloroferrates show the usual paramagnetism, the m-oxobis(trichloroferrate) exhibits unexpectedly strong antiferromagnetic coupling, as was observed by NMR experiments and susceptibility measurements. To investigate structure-property relations in functionalized ionic liquids, a set of protic, primary alkylammonium and aprotic, quarternary trimethylalkylammonium based ionic liquids was synthesized, and characterized. The length of the alkyl chain was systematically varied, and all compounds were synthesized with and without hydroxyl group, as well as formate and bis(triflyl)amide salts, aiming at getting insight into the influence of the different structure parts on the respective ionic liquid's properties.

  15. Effect of temperature and ionic strength on volumetric and acoustic properties of solutions of urea alkyl derivatives in aqueous NaCl

    International Nuclear Information System (INIS)

    Highlights: • Urea and its alkyl derivatives in aqueous NaCl solutions were studied. • The density and the speed of sound were measured for presented systems. • The strongest impact of NaCl on obtained quantities is noticed for apparent molar compression. • Bigger hydrophobic character of the solute results in bigger changes of calculated quantities with concentration. • The geometry of the solute is a crucial condition for hydrophobic hydration to happen. - Abstract: The present work was undertaken to study volumetric and acoustic properties for diluted solutions of tetramethylurea in pure water and for urea, n-propylurea, n-butylurea and tetramethylurea in 0.5 or 1 mol · dm−3 aqueous solutions of sodium chloride. This paper presents measured values of densities and sound velocities at T = (288.15, 298.15 and 308.15) K. From these data the apparent molar volumes, VΦ, adiabatic compressibilities, κS, and apparent molar adiabatic compressions, KS,Φ, were obtained. The values of apparent molar volumes for infinite dilution and limited apparent adiabatic compressions were calculated from extrapolation of the concentration dependence. Further, the corresponding transfer data as well as hydration number of urea and its derivatives in the studied systems were estimated. The obtained parameters are discussed in terms of various solute-solvent and solute-cosolute interactions

  16. Learning Ionic

    CERN Document Server

    Ravulavaru, Arvind

    2015-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    巩育军; 牛盛童; 黄学锋; 王键

    2014-01-01

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

  18. Ion Association, Solubilities, and Reduction Potentials in Aqueous Solution.

    Science.gov (United States)

    Russo, Steven O.; Hanania, George I. H.

    1989-01-01

    Incorporates the combined effects of ionic strength and ion association to show how calculations involving ionic equilibria are carried out. Examines the variability of reduction potential data for two aqueous redox systems. Provides several examples. (MVL)

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

    Indian Academy of Sciences (India)

    Cecilia Devi Wilfred; Fadwa Babiker Mustafa

    2013-11-01

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

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

    Science.gov (United States)

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

    1998-09-01

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

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

    Science.gov (United States)

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

    2011-12-29

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

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

    Science.gov (United States)

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

    2007-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

    王玉峰; 陈琳琳; 邓凡政

    2011-01-01

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

  4. Ionic Liquids to Replace Hydrazine

    Science.gov (United States)

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

    2011-01-01

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

  5. Water in Room Temperature Ionic Liquids

    Science.gov (United States)

    Fayer, Michael

    2014-03-01

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

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

    Science.gov (United States)

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

    2016-08-17

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

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

    Science.gov (United States)

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

    2012-11-06

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

  8. Aqueous biphasic systems with ionic liquids

    OpenAIRE

    Neves, Catarina Maia Seco Seiça

    2009-01-01

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

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

    Science.gov (United States)

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

  10. Ionic liquid polyoxometalates as light emitting materials

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-01-01

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

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

    Science.gov (United States)

    Patil, Amol Baliram; Bhanage, Bhalchandra Mahadeo

    2016-06-21

    The nature of bonding interactions between the cation and the anion of an ionic liquid is at the heart of understanding ionic liquid properties. A particularly interesting case is a special class of ionic liquids known as protic ionic liquids. The extent of proton transfer in protic ionic liquids has been observed to vary according to the interacting species. Back proton transfer renders protic ionic liquids volatile and to be considered as inferior ionic liquids. We try to address this issue by employing modern ab initio valence bond theory calculations. The results indicate that the bonding in the cation and the anion of a prototypical ionic liquid, ethylammonium nitrate, is fundamentally different. It is neither characteristic of covalent/polar covalent bonding nor ionic bonding but rather charge shift bonding as a resonance hybrid of two competing ionic molecular electronic structure configurations. An investigation of other analogous protic ionic liquids reveals that this charge shift bonding seems to be a typical characteristic of protic ionic liquids while the ionic solid analogue compound ammonium nitrate has less charge shift bonding character as compared to protic ionic liquids. Further the extent of charge shift bonding character has been found to be congruent with the trends in many physicochemical properties such as melting point, conductivity, viscosity, and ionicity of the studied ionic liquids indicating that percentage charge shift character may serve as a key descriptor for large scale computational screening of ionic liquids with desired properties. PMID:27229870

  12. Quantized ionic conductance in nanopores

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-01-01

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

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

    Science.gov (United States)

    Li, Zaiwei; Tang, Yongchun; Cheng; Jihong

    2009-11-10

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

  14. Thermotropic Ionic Liquid Crystals

    OpenAIRE

    Sabine Laschat; Axenov, Kirill V

    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.

  15. Aqueous systems and geothermal energy

    International Nuclear Information System (INIS)

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

  16. Aqueous chemistry of iodine

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

    Weinberg, Roberto F.; Hasalová, Pavlína

    2015-01-01

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

  18. Hydrophobic ionic liquids

    Science.gov (United States)

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

    1998-01-01

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

  19. In-reactor testing of ionic thermometers

    International Nuclear Information System (INIS)

    Ionic thermometers have been tested in a nuclear reactor with attention to the steepness of the ionic conductivity jump and the influence of a glass container on the accuracy of the temperature measurements. It was found that, at the neutron fluxes up to 1.5 x 1018 m-2 s-1 (thermal) and 3 x 1018 m-2 s-1 (fast) in a light water reactor, the change of conductivity jump slope is negligible or nil for an ionic thermometer filled by HgI2, i.e., at 256.0 +- 0.2 0C. The need to use boron-free glass was confirmed. The impact on the accuracy of the temperature point indication in a nuclear reactor core is discussed, as well as obvious inertness of the melting process mechanism to the intense irradiation field

  20. Acidic Ionic Liquids.

    Science.gov (United States)

    Amarasekara, Ananda S

    2016-05-25

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

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

    Czech Academy of Sciences Publication Activity Database

    Weinberg, R. F.; Hasalová, Pavlína

    212-215, January (2015), s. 158-188. ISSN 0024-4937 Institutional support: RVO:67985530 Keywords : aqueous fluids * crustal anatexis * granites * silicate melts * water-fluxed melting Subject RIV: DB - Geology ; Mineralogy Impact factor: 4.482, year: 2014

  2. Atomic dynamics of alumina melt: A molecular dynamics simulation study

    OpenAIRE

    Jahn, S.; P. A. Madden

    2008-01-01

    The atomic dynamics of Al2O3 melt are studied by molecular dynamics simulation. The particle interactions are described by an advanced ionic interaction model that includes polarization effects and ionic shape deformations. The model has been shown to reproduce accurately the static structure factors S(Q) from neutron and x-ray diffraction and the dynamic structure factor S(Q,ω) from inelastic x-ray scattering. Analysis of the partial dynamic structure factors shows inelastic features in the ...

  3. Design of Separation Processes with Ionic Liquids

    DEFF Research Database (Denmark)

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

    2015-01-01

    A systematic methodology for screening and designing of Ionic Liquid (IL)-based separation processes is proposed and demonstrated using several case studies of both aqueous and non-aqueous systems, for instance, ethanol + water, ethanol + hexane, benzene + hexane, and toluene + methylcyclohexane....... The best four ILs of each mixture are [mmim][dmp], [emim][bti], [emim][etso4] and [hmim][tcb], respectively. All of them were used as entrainers in the extractive distillation. A process simulation of each system was carried out and showed a lower both energy requirement and solvent usage as compared...

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

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

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

  5. Periodicity and map for discovery of new ionic liquids

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Suojiang

    2006-01-01

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

  6. Electromechanical Transduction in Ionic Liquid-Swollen Nafion Membranes

    OpenAIRE

    Bennett, Matthew Damon

    2005-01-01

    Traditionally, water has been used as the diluent for ionomeric polymer transducers. The water mobilizes the counterions within the polymer and allows electromechanical transduction to occur. However, these water-swollen devices have limited stability when operated in a non-aqueous environment. In this work, ionic liquids are demonstrated as viable diluents for ionomeric polymer transducers based on Nafion membranes. Ionic liquids are molten salts that are highly thermally stable and have...

  7. Protic Cationic Oligomeric Ionic Liquids of the Urethane Type

    DEFF Research Database (Denmark)

    Shevchenko, V. V.; Stryutsky, A. V.; Klymenko, N. S.; Gumennaya, M. A.; Fomenko, A. A.; Trachevsky, V. V.; Davydenko, V. V.; Bliznyuk, V. N.; Dorokhin, Andriy

    2014-01-01

    Protic oligomeric cationic ionic liquids of the oligo(ether urethane) type are synthesized via the reaction of an isocyanate prepolymer based on oligo(oxy ethylene)glycol with M = 1000 with hexamethylene-diisocyanate followed by blocking of the terminal isocyanate groups with the use of amine...... derivatives of imidazole, pyridine, and 3-methylpyridine and neutralization of heterocycles with ethanesulfonic acid and p-toluenesulfonic acid. The structures and properties of the synthesized oligomeric ionic liquids substantially depend on the structures of the ionic groups. They are amorphous at room...... temperature, but ethanesulfonate imidazolium and pyridinium oligomeric ionic liquids form a low melting crystalline phase. The proton conductivities of the oligomeric ionic liquids are determined by the type of cation in the temperature range 80-120 degrees C under anhydrous conditions and vary within five...

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

    Science.gov (United States)

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

    2016-03-10

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

  9. Ionic conductivity and molecular dynamic behavior in supramolecular ionic networks; the effect of lithium salt addition

    International Nuclear Information System (INIS)

    Highlights: • Novel amorphous and semicrystalline supramolecular ionic networks, iNets, have been synthesised by self-assembly of dicationic and dianionic molecules. • Significant enhancement of conductivity of the semicrystalline iNets has been achieved upon doping with LiTFSI. • Solid state NMR of the semicrystalline iNets shows narrower lines upon doping due to increased mobility in the network. - Abstract: Supramolecular ionic networks combine singular properties such as self-healing behaviour and ionic conductivity. In this work we present an insight into the ionic conductivity and molecular dynamic behaviour of an amorphous and semicrystalline supramolecular ionic networks (iNets) that were synthesised by self-assembly of difunctional imidazolium dicationic molecules coupled with (trifluoromethane-sulfonyl) imide dianionic molecules. Relatively low ionic conductivity values were obtained for the semicrystalline iNet below its melting point (Tm = 101 °C) in comparison with the amorphous iNet for which the conductivity significantly increased (∼3 orders of magnitude) above 100 °C. Upon LiTFSI doping, the semicrystalline iNet reached conductivity values ∼ 10−3 S cm−1 due to enhanced mobility of the network which was supported by solid-state static NMR. Furthermore, the overlapping of 19F and 7Li resonance lines from both the semicrystalline network and the LiTFSI suggests fast molecular motions

  10. Melting of Pb nanocrystals

    International Nuclear Information System (INIS)

    The size-dependent melting and surface melting of Pb nanocrystals is demonstrated by x-ray powder diffraction in ultrahigh vacuum. Whereas some prior studies have measured the size-dependent melting temperature via the diffraction intensity, it is shown here that crystallite reorientation makes the diffraction intensity an unreliable indicator of melting. Instead of the diffraction intensity, the diffraction peak shape reveals the size-dependent melting via changes in the crystallite size distribution. Measurements showed that the melting temperature varies inversely with the crystallite size and quantitatively favors the liquid-skin melting model over the homogeneous melting model. Surface melting is demonstrated via the reversible growth of a 0.5 nm liquid skin on 50 nm crystallites just below the size-dependent melting temperature. copyright 1998 The American Physical Society

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-08-15

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

  12. Catalysis in Molten Ionic Media

    DEFF Research Database (Denmark)

    Boghosian, Soghomon; Fehrmann, Rasmus

    2013-01-01

    identified easily. It has been shown that the melt consists of vanadium oxosulfato complexes in the oxidation states III-V in an alkali pyrosulfate solvent. However, many basic data for alkali pyrosulfates and oxosulfato vanadates have turned out to be either nonexisting or unreliable. As a result, the...... of vanadium compounds, of which the majority are identified as catalyst deactivation products; and (v) studies of molecular structure and catalytic activity. Finally, the reaction mechanism is highlighted, which represents the state of the art of that catalytic process by 2013. © 2013 Elsevier Inc......This chapter deals with catalysis in molten salts and ionic liquids, which are introduced and reviewed briefly, while an in-depth review of the oxidation catalyst used for the manufacturing of sulfuric acid and cleaning of flue gas from electrical power plants is the main topic of the chapter. The...

  13. Non-Aqueous Capillary Electrophoresis

    Science.gov (United States)

    Szumski, Michał; Buszewski, Bogusław

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

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

    Science.gov (United States)

    Rout, Alok; Binnemans, Koen

    2015-01-21

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

  15. Ionic liquid tunes microemulsion curvature.

    Science.gov (United States)

    Liu, Liping; Bauduin, Pierre; Zemb, Thomas; Eastoe, Julian; Hao, Jingcheng

    2009-02-17

    Middle-phase microemulsions formed from cationic dioctadecyldimethylammonium chloride (DODMAC), anionic sodium dodecylsulfate (SDS), n-butanol, and n-heptane were studied. An ionic liquid (IL), 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]), was employed as the electrolyte in the aqueous media instead of inorganic salts usually used in microemulsion formulation. Studies have been carried out as a function of the concentrations of [bmim][BF4], n-butanol, total surfactant (cDODMAC+SDS), and temperature on the phase behavior and the ultralow interfacial tensions in which the anionic component is present in excess in the catanionic film. Ultralow interfacial tension measurements confirmed the formation of middle-phase microemulsions and the necessary conditions for stabilizing middle-phase microemulsions. Electrical conductivity, small-angle X-ray scattering (SAXS), and small-angle neutron scattering (SANS) experiments were also performed, indicating that the typical heptane domain size has an average radius of 360 A and the ionic liquid induces softening of the charged catanionic film. Most interestingly, the IL concentration (cIL) is shown to act as an effective interfacial curvature-control parameter, representing a new approach to tuning the formulation of microemulsions and emulsions. The results expand the potential uses of ILs but also point to the design of new ILs that may achieve superefficient control over interfacial and self-assembly systems. PMID:19161325

  16. Functional ionic liquids; Funktionelle ionische Fluessigkeiten

    Energy Technology Data Exchange (ETDEWEB)

    Baecker, Tobias

    2012-07-01

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

  17. Melting of Transition Metals

    Energy Technology Data Exchange (ETDEWEB)

    Ross, M; Japel, S; Boehler, R

    2005-04-11

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

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

    Science.gov (United States)

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

    2016-04-01

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

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

    Science.gov (United States)

    Detweiler, Zachary M.

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

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

    DEFF Research Database (Denmark)

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

    1989-01-01

    A new, inorganic low melting electrolyte with the composition LiAlCl4-NaAlCl4-NaAlBr4-KAlCl4 (3:2:3:2) [or equivalentlyLiAlBr4-NaAlCl4-KAlCl4 (3:5:2)] has been developed. The melting point for this neutral melt is 86°C; the decompositionpotential is approximately 2.0V; the ionic conductivity...

  1. Charge transport properties of cryolite–silica melts

    International Nuclear Information System (INIS)

    Electrodeposition of silicon from a cryolite based electrolyte at a relatively low temperature is a promising approach to generate high purity silicon. In order to obtain fundamental data pertaining to electrowinning of silicon from cryolite–SiO2 melts, charge transport properties of the melt such as conductivity and electronic and ionic transference numbers were measured. Each property was determined for a range of temperatures and SiO2 contents. It was found that addition of silica to cryolite generally decreases the transport rate of charge carriers. The temperature on the other hand had a positive effect on the electronic and ionic conductivities. The variations arise from the structural changes in the melt, particularly formation of complex ions involving Na, Si, and Al.

  2. Microwave melting device

    International Nuclear Information System (INIS)

    Low level radioactive wastes (concrete pieces) or materials to be melted such as burnt ashes of wastes are charged into a melting furnace. Then, gyrotron of a microwave generator is oscillated, and generated microwaves of a large power are introduced to a melting furnace by a waveguide. The microwaves are irradiated from an irradiator to a beam converging-type reflecting mirror antenna disposed opposite to the irradiator. Then, an antenna driving portion is operated to rotate and move the antenna in parallel. With such procedures, the microwaves of a large power are converged acutely in a beam-like manner to a predetermined range in the melting furnace, and the converged beams of the microwaves are scanned. This can generate heat from the inner side of the materials to be melted charged to the melting furnace by the induction loss and they are melted. (I.N.)

  3. Furfural production using ionic liquids: A review.

    Science.gov (United States)

    Peleteiro, Susana; Rivas, Sandra; Alonso, José Luis; Santos, Valentín; Parajó, Juan Carlos

    2016-02-01

    Furfural, a platform chemical with a bright future, is commercially obtained by acidic processing of xylan-containing biomass in aqueous media. Ionic liquids (ILs) can be employed in processed for furfural manufacture as additives, as catalysts and/or as reaction media. Depending on the IL utilized, externally added catalysts (usually, Lewis acids, Brönsted acids and/or solid acid catalysts) can be necessary to achieve high reaction yields. Oppositely, acidic ionic liquids (AILs) can perform as both solvents and catalysts, enabling the direct conversion of suitable substrates (pentoses, pentosans or xylan-containing biomass) into furfural. Operating in IL-containing media, the furfural yields can be improved when the product is continuously removed along the reaction (for example, by stripping or extraction), to avoid unwanted side-reactions leading to furfural consumption. These topics are reviewed, as well as the major challenges involved in the large scale utilization of ILs for furfural production. PMID:26708486

  4. Ionic liquid-induced synthesis of selenium nanoparticles

    International Nuclear Information System (INIS)

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

  5. Extraction behavior of Am(III) in benzoyl pyrazolone dissolved in pyrolidnium ionic liquid

    International Nuclear Information System (INIS)

    Extraction of Am(III) from nitric acid medium was carried out in a solution of benzoylpyrazolone (HPMBP) dissolved in 1-butyl-3-methylpyrrolidinium bis(trifluoro-methanesulfonyl)imide ((C4mpyr)(NTf2)) ionic liquid. The extraction behavior of Am(III) in ionic liquid phase was investigated as a function of pH of the aqueous phase. The extraction behavior in ionic liquid was compared with those observed in n-dodecane and the stripping of Am(III) from the loaded ionic liquid phase was carried out using concentrated nitric acid. (author)

  6. Ionic Liquids in Tribology

    Directory of Open Access Journals (Sweden)

    Ichiro Minami

    2009-06-01

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

  7. Melt containment member

    Science.gov (United States)

    Rieken, Joel R.; Heidloff, Andrew J.

    2014-09-09

    A tubular melt containment member for transient containment of molten metals and alloys, especially reactive metals and alloys, includes a melt-contacting layer or region that comprises an oxygen-deficient rare earth oxide material that is less reactive as compared to the counterpart stoichiometric rare earth oxide. The oxygen-deficient (sub-stoichiometric) rare earth oxide can comprise oxygen-deficient yttria represented by Y.sub.2O.sub.3-x wherein x is from 0.01 to 0.1. Use of the oxygen-deficient rare earth oxide as the melt-contacting layer or region material reduces reaction with the melt for a given melt temperature and melt contact time.

  8. Properties of small Ar sub N-1 K/+/ ionic clusters

    Science.gov (United States)

    Etters, R. D.; Danilowicz, R.; Dugan, J.

    1977-01-01

    A self-consistent formalism is developed that, based upon a many-body potential, dynamically determines the thermodynamic properties of ionic clusters without an a priori designation of the equilibrium structures. Aggregates consisting of a single closed shell K(+) ion and N-1 isoelectronic argon atoms were studied. The clusters form crystallites at low temperatures, and melting transitions and spontaneous dissociations are indicated. The results confirm experimental evidence that shows that ionic clusters become less stable with increasing N. The crystallite structures formed by four different clusters are isosceles triangle, skewed form, octahedron with ion in the middle, and icosahedron with the ion in the middle.

  9. Model of interfacial melting

    DEFF Research Database (Denmark)

    Mouritsen, Ole G.; Zuckermann, Martin J.

    1987-01-01

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

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

    Science.gov (United States)

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

    2006-10-26

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

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

    OpenAIRE

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

    2009-01-01

    A multi-walled nanotube (MWNT) ionic liquid was prepared by the immobilization of 1-butylimidazole bromide onto an epoxy group on a poly(glycidyl methacrylate)-grafted MWNT, which was synthesized by radiation-induced graft polymerization of glycidyl methacrylate onto MWNT in an aqueous solution. Subsequently, a MWNT ionic liquid electrode was fabricated by hand-casting MWNT ionic liquid, tyrosinase, and chitosan solution as a binder on indium tin oxide (ITO) glass. The sensing ranges of the M...

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

    OpenAIRE

    Lancel, Gilles

    2016-01-01

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

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

    Science.gov (United States)

    El Abedin, Sherif Zein; Endres, Frank

    2007-11-01

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

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

    OpenAIRE

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

    2005-01-01

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

  15. Radiation-induced degradation of carboxymethylated chitosan and its application in preparation of ionic liquids and silver nanoparticles

    International Nuclear Information System (INIS)

    Radiation effect of γ-ray on carboxymethylated chitosan (CM-chitosan) in solid state and aqueous solution were studied. The changes in molecular weight of CM-chitosan with absorbed dose were monitored by viscosity method. In solid state, there are random chain scissions in the radiation process of CM-chitosan. XRD patterns identified that the degradation of CM-chitosan occurred mostly in amorphous region. Radiation chemical yield (Gd) of CM-chitosan in solid state in N2 atmosphere was 0.49, which showed CM-chitosan has high radiation stability. Biomaterials composed of CM-chitosan can be thought to sterilize with low absorbed doses. While aqueous solutions of CM-chitosan were irradiated with γ-rays in various conditions, degradations of CM-chitosan were faster in the presence of nitrous oxide or hydrogen peroxide, however, it was inhibited obviously by adding isopropanol because of concentration changes of hydroxyl radicals in different conditions. This indicated that hydroxyl radicals play an important role in radiation degradation of CM-chitosan. Furthermore, FTIR and UV spectra of CM-chitosan radiation-degraded in its solid state status or in aqueous solution showed that main chain structures of CM-chitosan were kept and some carbonyl/carboxyl groups formed during the irradiation were similar to radiation degradation products of chitosan. The method can be used to prepare low molecular weight CM-chitosan. Due to special physical and chemical properties, ionic liquids have attracted much attention in green chemistry field. Environment-friendly ionic liquids ([emim]CM-chitosan) were prepared in acid-base neutralization reactions based on 1-ethyl-3-methylimidazolium hydroxide and CM-chitosan with molecular weights ranging from 2000 to 600 Da. Results of thermal analysis showed that molecular weight of CM-chitosan have little influence on glass transition temperature, melting point and decomposing temperature of [emim]CM-chitosan ionic liquids. Conductivities of

  16. Thermodynamics of Glass Melting

    Science.gov (United States)

    Conradt, Reinhard

    First, a model based on linear algebra is described by which the thermodynamic properties of industrial multi-component glasses and glass melts can be accurately predicted from their chemical composition. The model is applied to calculate the heat content of glass melts at high temperatures, the standard heat of formation of glasses from the elements, and the vapor pressures of individual oxides above the melt. An E-fiber glass composition is depicted as an example. Second, the role of individual raw materials in the melting process of E-glass is addressed, with a special focus on the decomposition kinetics and energetic situation of alkaline earth carriers. Finally, the heat of the batch-to-melt conversion is calculated. A simplified reaction path model comprising heat turnover, content of residual solid matter, and an approach to batch viscosity is outlined.

  17. Electrowinning of UO2 from ionic liquid medium

    International Nuclear Information System (INIS)

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

  18. Antimicrobial Ionic Liquids with Fumarate Anion

    Directory of Open Access Journals (Sweden)

    Biyan He

    2013-01-01

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

  19. Preparation of diffusion coatings in ion-electron melts

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

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

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

    OpenAIRE

    Miguel A. Romero

    2016-01-01

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

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

    OpenAIRE

    Zech, Oliver

    2010-01-01

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

  2. Scalable synthesis of ionic liquids: comparison of performances of microstructured and stirred batch reactors

    OpenAIRE

    Iken, Hicham; Guillen, Frédéric; Chaumat, Hélène; Mazières, Marie-Rose; Plaquevent, Jean-Christophe; Tzedakis, Théodore

    2012-01-01

    A range of alkylpyridinium bromide ionic liquids have been synthesized in a stirred reactor at multigram scale and characterized by physical methods (viscosity, conductivity, melting point, electrochemical window, and water content). One ionic liquid, octylpyridinium bromide, was chosen to be synthesized in both macro and reduced scale reactors, in order to compare its performance and to afford evidence of the advantages of a cross channel micro reactor (channel width = 1 mm) compared to a st...

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

    International Nuclear Information System (INIS)

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

  4. Acrylate Functionalized Tetraalkylammonium Salts with Ionic Liquid Properties

    Directory of Open Access Journals (Sweden)

    Silvia Janietz

    2012-05-01

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

  5. Signatures of nonthermal melting

    Directory of Open Access Journals (Sweden)

    Tobias Zier

    2015-09-01

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

  6. Modeling reactive geochemical transport of concentrated aqueous solutions

    Science.gov (United States)

    Zhang, Guoxiang; Zheng, Zuoping; Wan, Jiamin

    2005-02-01

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

  7. Applications of functionalized ionic liquids

    Institute of Scientific and Technical Information of China (English)

    LI Xuehui; ZHAO Dongbin; FEI Zhaofu; WANG Lefu

    2006-01-01

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

  8. Radiation chemistry of ionic liquids

    International Nuclear Information System (INIS)

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

  9. Ionic and Molecular Liquids

    DEFF Research Database (Denmark)

    Chaban, Vitaly V.; Prezhdo, Oleg

    2013-01-01

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

  10. Entropy and Ionic Conductivity

    OpenAIRE

    Zhang, Yong-Jun

    2012-01-01

    It is known that the ionic conductivity can be obtained by using the diffusion constant and the Einstein relation. We derive it here by extracting it from the steady electric current which we calculate in three ways, using statistics analysis, an entropy method, and an entropy production approach.

  11. Ionic smoke detectors

    CERN Document Server

    2002-01-01

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

  12. Parameters of deep melts in the Sierra-Leone region, Central Atlantic (data on melt inclusions)

    Science.gov (United States)

    Simonov, V. A.; Glazyrin, Yu. E.; Kovyazin, S. V.

    2003-04-01

    Samples, collected during 22 cruise of R/V "Academician Nikolaj Strakhov" in the Sierra Leone F.Z. Region, Central Atlantic (Peyve et al., 2000) were investigated. The features of geology and volcanism of this region were reviewed in the last publications (Peyve et al., 2003; Skolotnev et al., 2003). In the present report the results of melt inclusions study in olivines and in plagioclases from basalts are given. The experiments with inclusions were carried out according published procedure (Simonov, 1993; Sobolev, Danyushevsky, 1994). The compositions of inclusions were established using a "Camebax-micro" electron microprobe. Contents of trace, rare earth elements and water in inclusions were determined on ionic microprobe IMS-4f on procedure published in the work (Sobolev, 1996). The analysis of melt inclusions in olivines from basalts has shown, that the magmas of the Mid-Atlantic Ridge (MAR) Rift Zone in the Sierra-Leone Region have sufficiently high temperatures of crystallization -- 1275--1340^oC. Comparison of homogenization temperatures with liquidus temperatures calculated according PETROLOG (Danyushevsky, 2001) show, that the most of data agree with limits of used thermometers. The presence of such temperature characteristics testifies that the inclusions characterize parameters of deep melts. Primary magmas in this region, according estimation on procedure (Schilling et al., 1995), were formed at parameters of mantle melting near 1340--1370^oC and 50--60 km (Simonov et al., 2001). Comparison with data on trace and rare earth elements in melt inclusions in olivines from rocks 9^o N MAR (Sobolev, 1997) demonstrates, that on an interrelation La/Sm--Zr/Y inclusions in olivines from Sierra-Leone Region are close to data on normal melts formed during melting of mantle with formation about 5% of melt. On a character of distribution of trace and rare earth elements melts in the Sierra-Leone Region are closer to magmas from north segments of MAR (8^o N), than

  13. Ionic-Liquid Based Separation of Azeotropic Mixtures

    DEFF Research Database (Denmark)

    Kulajanpeng, Kusuma; Suriyapraphadilok, Uthaiporn; Gani, Rafiqul

    2014-01-01

    stability, toxicity, and environmental impacts of the ILs. A Hildebrand solubility parameter group contribution model for ILs is highlighted to screen the miscibility of the ILs with the target solute component which was considered as a key target property to further screen the candidates from the previous......methodology for the screening of ionic liquids (ILs) as entrainers for ILs-based separation processes in binary aqueous azeotropic systems (e.g., water + ethanol and water + isopropanol) is presented. Ionic liquids as entrainers were first screened based on a combination of criteria such as...... [C1MIM][DMP]. For the final evaluation, the best candidates for aqueous systems were used as entrainers, and then the vapor-liquid equilibrium (VLE) of the ternary systems containing ILs was predicted by the Non Random Two Liquids (NRTL) model to confirm the breaking of the azeotrope. Based on...

  14. Single-Molecule Electrochemical Gating in Ionic Liquids

    DEFF Research Database (Denmark)

    Kay, Nicola J.; Higgins, Simon J.; Jeppesen, Jan O.;

    2012-01-01

    The single-molecular conductance of a redox active molecular bridge has been studied in an electrochemical single-molecule transistor configuration in a room-temperature ionic liquid (RTIL). The redox active pyrrolo-tetrathiafulvalene (pTTF) moiety was attached to gold contacts at both ends through...... −(CH2)6S– groups, and gating of the redox state was achieved with the electrochemical potential. The water-free, room-temperature, ionic liquid environment enabled both the monocationic and the previously inaccessible dicationic redox states of the pTTF moiety to be studied in the in situ scanning...... relaxation. Using this view, reorganization energies of ∼1.2 eV have been estimated for both the first and second redox transitions for the pTTF bridge in the 1-butyl-3-methylimidazolium trifluoromethanesulfonate (BMIOTf) ionic liquid environment. By contrast, in aqueous environments, a much smaller...

  15. Model of interfacial melting

    OpenAIRE

    Mouritsen, Ole G.; Zuckermann, Martin J.

    1987-01-01

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

  16. Melt fracture revisited

    Energy Technology Data Exchange (ETDEWEB)

    Greenberg, J. M.

    2003-07-16

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

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

    OpenAIRE

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

    2011-01-01

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

  18. Chain and Ion Dynamics in Ionomer Melts

    Science.gov (United States)

    Register, Richard A.

    2003-03-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-07-01

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

  20. NON-AQUEOUS DISSOLUTION OF MASSIVE PLUTONIUM

    Science.gov (United States)

    Reavis, J.G.; Leary, J.A.; Walsh, K.A.

    1959-05-12

    A method is presented for obtaining non-aqueous solutions or plutonium from massive forms of the metal. In the present invention massive plutonium is added to a salt melt consisting of 10 to 40 weight per cent of sodium chloride and the balance zinc chloride. The plutonium reacts at about 800 deg C with the zinc chloride to form a salt bath of plutonium trichloride, sodium chloride, and metallic zinc. The zinc is separated from the salt melt by forcing the molten mixture through a Pyrex filter.

  1. Pressure-induced melting of micellar crystal

    DEFF Research Database (Denmark)

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

    1993-01-01

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

  2. Flow of Aqueous Humor

    Science.gov (United States)

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

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-04-01

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

  5. Extraction of Americium(III) by diglycolamides in ionic liquids

    International Nuclear Information System (INIS)

    In the present work, the extraction behavior of Am(lII) in the three isomeric DGAs, TODGA, DEHDODGA and TEHDGA in two ionic liquids, 1-butyl-3-methylimidazolium bis(triflouromethane sulphonyl)imide (C4mimNTf2) and 1-butyl-1-methylpyrrolidinium bis(triflouromethanesulphonyl)imide (C4mpyNTf2) is compared. The distribution ratio of americium was determined at various acidities ranging from 1M to 8M. The distribution values were found to decrease with increase in aqueous phase acidity upto 3M. The DAm values then marginally increased with increase of acidity from 3 to 4M followed by a decrease in distribution values. The distribution ratio obtained for various DGAs followed the order TEHDGA < TODGA < DEHDODGA at aqueous phase acidities ranging from 1-4 M. When the aqueous nitric acid concentration was higher than 4M, the distribution values followed the order DEHDODGA < TEHDGA < TODGA. The anomalous behaviour of unsymmetrical diglycolamide in ionic liquid medium was investigated by IR spectroscopy. The study revealed that the unprotonated fraction of DGA (i.e. the free DGA) increased in the order TEHDGA < TODGA < DEHDODGA, which seems to be responsible for the observed anomalous extraction trend in DEHDODGA in ionic liquid medium

  6. Chemical reactions at aqueous interfaces

    Science.gov (United States)

    Vecitis, Chad David

    2009-12-01

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

  7. Nanoscale Ionic Materials

    KAUST Repository

    Rodriguez, Robert

    2008-11-18

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

  8. Multilayer Ionic Transducers

    OpenAIRE

    Akle, Barbar Jawad

    2003-01-01

    A transducer consisting of multiple layers of ionic polymer material is developed for applications in sensing, actuation, and control. The transducer consists of two to four individual layers each approximately 200 microns thick. The transducers are connected in parallel to minimize the electric field requirements for actuation. The tradeoff in deflection and force can be controlled by controlling the mechanical constraint at the interface. Packaging the transducer in an outer coating produce...

  9. Cyclic phosphonium ionic liquids

    Directory of Open Access Journals (Sweden)

    Sharon I. Lall-Ramnarine

    2014-01-01

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

  10. Novel Ionic Liquid with Both Lewis and Brønsted Acid Sites for Michael Addition

    OpenAIRE

    Runpu Shen; Xiaohua Song; Wenxin Ma; Xuejun Lao; Xiaoyue Jiang; Weidong Ye

    2011-01-01

    Ionic liquid with both Lewis and Brønsted acid sites has been synthesized and its catalytic activities for Michael addition were carefully studied. The novel ionic liquid was stable to water and could be used in aqueous solution. The molar ratio of the Lewis and Brønsted acid sites could be adjusted to match different reactions. The results showed that the novel ionic liquid was very efficient for Michael addition with good to excellent yields within several min. Operational simplicity, high ...

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

    Institute of Scientific and Technical Information of China (English)

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

    2008-01-01

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

  12. Course on Ionic Channels

    CERN Document Server

    1986-01-01

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

  13. Selective Single-Step Separation of a Mixture of Three Metal Ions by a Triphasic Ionic-Liquid-Water-Ionic-Liquid Solvent Extraction System.

    Science.gov (United States)

    Vander Hoogerstraete, Tom; Blockx, Jonas; De Coster, Hendrik; Binnemans, Koen

    2015-08-10

    In a conventional solvent extraction system, metal ions are distributed between two immiscible phases, typically an aqueous and an organic phase. In this paper, the proof-of-principle is given for the distribution of metal ions between three immiscible phases, two ionic liquid phases with an aqueous phase in between them. Three-liquid-phase solvent extraction allows separation of a mixture of three metal ions in a single step, whereas at least two steps are required to separate three metals in the case of two-liquid-phase solvent extraction. In the triphasic system, the lower organic phase is comprised of the ionic liquid betainium- or choline bis(trifluoromethylsulfonyl)imide, whereas the upper organic phase is comprised of the ionic liquid trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)imide. The triphasic system was used for the separation of a mixture of tin(II), yttrium(III), and scandium(III) ions. PMID:26178665

  14. Freezing of liquid alkali metals as screened ionic plasmas

    International Nuclear Information System (INIS)

    The relationship between Wigner crystallization of the classical ionic plasma and the liquid-solid transition of alkali metals is examined within the density wave theory of freezing. Freezing of the classical plasma on a rigid neutralizing background into the bcc structure is first re-evaluated, in view of recent progress in the determination of its thermodynamic functions by simulation and of the known difficulties of the theory relating to the order parameter at the (200) star of reciprocal lattice vectors. Freezing into the fcc structure is also considered in this context and found to be unfavoured. On allowing for long-wavelength deformability of the background, the ensuing appearance of a volume change on freezing into the bcc structure is accompanied by reduced stability of the fluid phase and by an increase in the entropy of melting. Freezing of alkali metals into the bcc structure is next evaluated, taking their ionic pair structure as that of an ionic plasma reference fluid screened by conduction electrons and asking that the correct ionic coupling strength at liquid-solid coexistence should be approximately reproduced. The ensuring values of the volume and entropy changes across the phase transition, as estimated from the theory by two alternative routes, are in reasonable agreement with experiment. The order parameters of the phase transition, excepting the (200) one, conform rather closely to a Gaussian behaviour and yield a Lindemann ratio in reasonable agreement with the empirical value for melting of bcc crystals. It is suggested that ionic ordering at the (200) star in the metal may be (i) assisted by medium range ordering in the conduction electrons, as indicated by differences in X-ray and neutron diffraction intensities from the liquid, and/or (ii) quite small in the hot bcc solid. Such a possible premelting behaviour of bcc metals should be worth testing experimentally by diffraction. (author). 48 refs, 1 fig., 1 tab

  15. IONIC LIQUIDS: PREPARATIONS AND LIMITATIONS

    OpenAIRE

    Dzulkefly Kuang Abdullah; Ahmad Adlie Shamsuri

    2010-01-01

    Ionic liquids are considered as an ideal alternative to volatile organic solvents and chemical industries in the future,because they are non-volatile. Ionic liquids are also considered as new novel chemical agents and widely regarded as agreener alternative to many commonly used solvents. Ionic liquids have been studied for a wide range of syntheticapplications and have attracted considerable interest for use as electrolytes in the areas of organic synthesis, catalysis,solar cell, fuel cells,...

  16. Inorganic materials synthesis in ionic liquids

    Directory of Open Access Journals (Sweden)

    Christoph Janiak

    2014-01-01

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

  17. Investigating ionic effects applied to water based organocatalysed aldol reactions.

    Science.gov (United States)

    Delaney, Joshua P; Henderson, Luke C

    2011-01-01

    Saturated aqueous solutions of various common salts were examined for their effect on aqueous aldol reactions catalysted by a highly active C(2)-symmetric diprolinamide organocatalyst developed in our laboratory. With respect to the aldol reaction between cyclohexanone and 4-nitrobenzaldehyde, deionised water was always a superior medium to salt solutions though some correlation to increasing anion size and depression in enantiomeric excess could be observed. Additionally, the complete inhibition of catalyst activity observed when employing tap water could be alleviated by the inclusion of ethylenediaminetetraacetate (EDTA) into the aqueous media prior to reaction initiation. Extension of these reaction conditions demonstrated that these ionic effects vary on a case-to-case basis depending on the ketone/aldehyde combination. PMID:22272120

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

    Directory of Open Access Journals (Sweden)

    Joshua P. Delaney

    2011-12-01

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

  19. Emerging melt quality control solution technologies for aluminium melt

    Institute of Scientific and Technical Information of China (English)

    Arturo Pascual, Jr

    2009-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Němec L.

    2013-12-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Ams, David A [Los Alamos National Laboratory

    2012-06-11

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

  2. Electrochemical aspects of ionic liquids

    CERN Document Server

    Ohno, Hiroyuki

    2011-01-01

    The second edition is based on the original book, which has been revised, updated and expanded in order to cover the latest information on this rapidly growing field. The book begins with a description of general and electrochemical properties of ionic liquids and continues with a discussion of applications in biochemistry, ionic devices, functional design and polymeric ionic liquids. The new edition includes new chapters on Li ion Batteries and Actuators, as well as a revision of existing chapters to include a discussion on purification and the effects of impurities, adsorption of ionic liqui

  3. Microwave Glass Melting Technology

    Czech Academy of Sciences Publication Activity Database

    Hájek, Milan

    Tokyo, 2001, s. 11-14. [Conference on Application of Microwave Energy in Industry. Tokyo (JP), 30.07.2001-03.08.2001] R&D Projects: GA AV ČR IBS4072003 Institutional research plan: CEZ:AV0Z4072921 Keywords : microwave * glass melting technology * application Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  4. Melting of graphene clusters

    OpenAIRE

    Singh, Sandeep Kumar; Neek-Amal, M.; Peeters, F. M.

    2013-01-01

    Density-functional tight-binding and classical molecular dynamics simulations are used to investigate the structural deformations and melting of planar carbon nano-clusters $C_{N}$ with N=2-55. The minimum energy configurations for different clusters are used as starting configuration for the study of the temperature effects on the bond breaking/rotation in carbon lines (N$

  5. Thermoreversible crystallization of charged colloids due to adsorption/desorption of ionic surfactants.

    Science.gov (United States)

    Murakado, Ai; Toyotama, Akiko; Yamamoto, Masaaki; Nagano, Ryota; Okuzono, Tohru; Yamanaka, Junpei

    2016-03-01

    We report that charged colloids exhibit thermoreversible crystallization via the adsorption of ionic surfactants onto particle surfaces. Due to the temperature dependence of the adsorption quantity, the colloids crystallized upon cooling and melted upon heating. To clarify the influences of surfactant adsorption on the crystallization, polystyrene (PS) particles dispersed in ethylene glycol (EG)/water mixtures were employed, enabling continuous tuning of the adsorption quantity by changing the EG concentration. The thermoreversible crystallization/melting behavior was found to be mainly attributable to changes in the ionic strength of the medium resulting from variation in the concentration of the non-adsorbed ionic surfactant molecules with temperature. We expect that the present findings will be useful for fine control of colloidal crystallization and the further study of colloidal crystallization in low permittivity media. PMID:26674236

  6. Viscosity Measurement for Tellurium Melt

    Science.gov (United States)

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

    2006-01-01

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

  7. Ionic Diffusion in High Temperature Uranium Dioxide

    International Nuclear Information System (INIS)

    Uranium dioxide nuclear fuels are being subjected to increasingly higher central temperatures and larger thermal gradients which contribute significantly to changes in the physical properties, to the distribution of fission products, to the oxide composition and specifically to the mechanism of material transport. The purpose of this paper is to discuss recent high temperature property measurements of UO2, made both in- and out-of-reactor, that pertain to atomic movement and to suggest further areas for high temperature thermodynamic research. High temperature measurements of electrical conductivity, thermo-electric EMF, solid state fission-fragment migration and studies of phase equilibria in the oxygen-uranium system suggest that ionic diffusion in an electrical potential gradient contributes significantly to the movement of fission products and oxygen. The electrical property measurements of uranium dioxide show evidence of a high Seebeck coefficient, a p-type to n-type conductivity change and an ionic character in high temperatures. These data are being confirmed by in-reactor electrical property measurements. The distribution of solid fission fragments observed in irradiated UO2 fuel elements cannot be explained solely in terms of diffusion in a thermal or concentration gradient. Solid fission fragments were shown to diffuse in an electric potential gradient at high temperatures in the absence of any thermal gradient.. The thermal EMF produced by the thermal gradient in a fuel element during irradiation is thought to contribute to the migration of fission fragments by ionic diffusion. In-reactor tests of this hypothesis are under way. The measurements and interpretation of high temperature property data are complicated by changes in stoichiometry. Phase equilibria and melting point studies in the temperaturè range 1600 -3000°C show a wide range of single phase UO2-x existing above 1600°C. The melting point of UO2-x reaches a maximum at approximately UO1

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2014-02-14

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-02-14

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-12-08

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

  12. Measurement of Latent Heat of Melting of Thermal Storage Materials for Dynamic Type Ice Thermal Storage

    Science.gov (United States)

    Sawada, Hisashi; Okada, Masashi; Nakagawa, Shinji

    In order to measure the latent heat of melting of ice slurries with various solute concentrations, an adiabatic calorimeter was constructed. Ice slurries were made from each aqueous solution of ethanol, ethylene glycol and silane coupling agent. The latent heat of melting of ice made from tap water was measured with the present calorimeter and the uncertainty of the result was one percent. Ice slurries were made both by mixing ice particles made from water with each aqueous solution and by freezing each aqueous solution with stirring in a vessel. The latent heat of melting of these ice slurries was measured with various concentrations of solution. The latent heat of melting decreased as the solute concentration or the freezing point depression increased. The latent heat of ice slurries made from ethanol or ethylene glycol aqueous solution agreed with that of ice made from pure water known already. The latent heat of melting of ice slurries made from silane coupling agent aqueous solution got smaller than that of ice made from pure water as the freezing point depression increased.

  13. Surface modification of nanodiamond in aqueous medium

    Institute of Scientific and Technical Information of China (English)

    许向阳; 朱永伟; 王柏春; 沈湘黔

    2003-01-01

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

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

    Science.gov (United States)

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

    2015-10-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2006-01-01

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

  16. Efficient extraction of Rh(III) from nitric acid medium using a hydrophobic ionic liquid.

    Science.gov (United States)

    Bell, Thomas James; Ikeda, Yasuhisa

    2012-04-21

    Rhodium(III) has been successfully extracted from an aqueous nitric acid solution using a hydrophobic ammonium based ionic liquid and CMPO or TODGA as extractant. This result has significant potential for the recovery of rhodium from spent nuclear fuel and thereby increasing the worldwide supply of this rare metal. PMID:22382888

  17. Precipitation of neptunium dioxide from aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, K E

    1999-12-01

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

  18. Melting of polydisperse hard disks

    NARCIS (Netherlands)

    Pronk, S.; Frenkel, D.

    2004-01-01

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

  19. Thermodynamics of Oligonucleotide Duplex Melting

    Science.gov (United States)

    Schreiber-Gosche, Sherrie; Edwards, Robert A.

    2009-01-01

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

  20. Melting and liquid structure of polyvalent metal halides

    International Nuclear Information System (INIS)

    A short review is given of recent progress in determining and understanding liquid structure types and melting mechanisms for halides of polyvalent metals. The nature of the preferred local coordination for the polyvalent metal ion in the melt can usually be ascertained from data on liquid mixtures with halogen-donating alkali halides. The stability of these local coordination states and the connectivity that arises between them in the approach to the pure melt determines the character of its short-range and possible medium-range order. A broad classification of structural and melting behaviours can be given on the basis of measured melting parameters and transport coefficients for many compounds, in combination with the available diffraction data on the liquid structure of several compounds. Correlations have been shown to exist with a simple indicator of the nature of the chemical bond and also with appropriate parameters of ionic models, wherever the latter are usefully applicable for semiquantitative calculations of liquid structure. Consequences on the mechanisms for valence electron localization in solutions of metallic elements into strongly structured molten salts are also briefly discussed. (author). 46 refs, 4 figs, 2 tabs

  1. Melting of clusters

    Energy Technology Data Exchange (ETDEWEB)

    Haberland, H. [Freiburg Univ., Facultat fur Physik (Germany)

    2001-07-01

    An experiment is described which allows to measure the caloric curve of size selected sodium cluster ions. This allows to determine rather easily the melting temperatures, and latent heats in the size range between 55 and 340 atoms per cluster. A more detailed analysis is necessary to show that the cluster Na{sub 147}{sup +} has a negative microcanonical heat capacity, and how to determine the entropy of the cluster from the data. (authors)

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

    Science.gov (United States)

    Lü, Y J; Wei, B

    2006-10-14

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2005-01-01

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

  4. Partitioning of lanthanides and Y between immiscible silicate and fluoride melts, fluorite and cryolite and the origin of the lanthanide tetrad effect in igneous rocks

    Science.gov (United States)

    Veksler, Ilya V.; Dorfman, Alexander M.; Kamenetsky, Maya; Dulski, Peter; Dingwell, Donald B.

    2005-06-01

    Some F-rich granitic rocks show anomalous, nonchondritic ratios of Y/Ho, extreme negative Eu anomalies, and unusual, discontinuous, segmented chondrite-normalised plots of rare earth elements (REE). The effects of F-rich fluids have been proposed as one of the explanations for the geochemical anomalies in the evolved granitic systems, as the stability of nonsilicate complexes of individual rare earths may affect the fluid-melt element partitioning. The lanthanide tetrad effect, related to different configurations of 4f-electron subshells of the lanthanide elements, is one of the factors affecting such complexing behaviour. We present the first experimental demonstration of the decoupling of Y and Ho, and the tetrad effect in the partitioning of rare earths between immiscible silicate and fluoride melts. Two types of experiments were performed: dry runs at atmospheric pressure in a high-temperature centrifuge at 1100 to 1200°C, and experiments with the addition of H 2O at 700 to 800°C and 100 MPa in rapid-quench cold-seal pressure vessels. Run products were analysed by electron microprobe (major components), solution-based inductively coupled plasma mass spectrometry (ICP-MS) (REE in the centrifuged runs), and laser ablation ICP-MS (REE and Li in the products of rapid-quench runs). All the dry centrifuge runs were performed at super-liquidus, two-phase conditions. In the experiments with water-bearing mixtures, minor amounts of aqueous vapour were present in addition to the melts. We found that lanthanides and Y concentrated strongly in the fluoride liquids, with two-melt partition coefficients reaching values as high as 100-220 in water-bearing compositions. In all the experimental samples, two-melt partition coefficients of lanthanides show subtle periodicity consistent with the tetrad effect, and the partition coefficient of Y is greater than that of Ho. One of the mixtures also produced abundant fluorite (CaF 2) and cryolite (Na 3AlF 6) crystals, which enabled

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

    Science.gov (United States)

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

    2016-04-01

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

  6. Wettability by Ionic Liquids.

    Science.gov (United States)

    Liu, Hongliang; Jiang, Lei

    2016-01-01

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

  7. Melt spinning study

    Science.gov (United States)

    Workman, Gary L.; Rathz, Thomas

    1993-01-01

    Containerless processing of materials provides an excellent opportunity to study nucleation phenomena and produce unique materials, primarily through the formation of metastable phases and deep undercoolings. Deep undercoolings can be readily achieved in falling drops of molten material. Extended solute solubilities and greatly refined microstructures can also be obtained in containerless processing experiments. The Drop Tube Facility at Marshall Space Flight Center has played an important role in enhancing that area of research. Previous experiments performed in the Drop Tube with refractory metals has shown very interesting microstructural changes associated with deep undercoolings. It is apparent also that the microstructure of the deep undercooled species may be changing due to the release of the latent heat of fusion during recalescence. For scientific purposes, it is important to be able to differentiate between the microstructures of the two types of metallic species. A review of the literature shows that although significant advances have been made with respect to the engineering aspects of rapid solidification phenomena, there is still much to be learned in terms of understanding the basic phenomena. The two major ways in which rapid solidification processing provides improved structures and hence improved properties are: (1) production of refined structures such as fine dendrites and eutectics, and (2) production of new alloy compositions, microstructures, and phases through extended solid solubility, new phase reaction sequences, and the formation of metallic-glass microstructures. The objective of this work has been to determine the optimal methodology required to extract this excess energy without affecting the thermo-physical parameters of the under-cooled melt. In normal containerless processing experiments recalescence occurs as the melt returns toward the melting point in order to solidify. A new type of experiment is sought in which the resultant

  8. Atomic dynamics of alumina melt: A molecular dynamics simulation study

    Directory of Open Access Journals (Sweden)

    S.Jahn

    2008-03-01

    Full Text Available The atomic dynamics of Al2O3 melt are studied by molecular dynamics simulation. The particle interactions are described by an advanced ionic interaction model that includes polarization effects and ionic shape deformations. The model has been shown to reproduce accurately the static structure factors S(Q from neutron and x-ray diffraction and the dynamic structure factor S(Q,ω from inelastic x-ray scattering. Analysis of the partial dynamic structure factors shows inelastic features in the spectra up to momentum transfers, Q, close to the principal peaks of partial static structure factors. The broadening of the Brillouin line widths is discussed in terms of a frequency dependent viscosity η(ω.

  9. Emerging melt quality control solution technologies for aluminium melt

    Directory of Open Access Journals (Sweden)

    Arturo Pascual, Jr

    2009-11-01

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

  10. Novel Ionic Liquid with Both Lewis and Brønsted Acid Sites for Michael Addition

    Directory of Open Access Journals (Sweden)

    Runpu Shen

    2011-10-01

    Full Text Available Ionic liquid with both Lewis and Brønsted acid sites has been synthesized and its catalytic activities for Michael addition were carefully studied. The novel ionic liquid was stable to water and could be used in aqueous solution. The molar ratio of the Lewis and Brønsted acid sites could be adjusted to match different reactions. The results showed that the novel ionic liquid was very efficient for Michael addition with good to excellent yields within several min. Operational simplicity, high stability to water and air, small amount used, low cost of the catalyst used, high yields, chemoselectivity, applicability to large-scale reactions and reusability are the key features of this methodology, which indicated that this novel ionic liquid also holds great potential for environmentally friendly processes.

  11. Simultaneous Design of Ionic Liquids and Azeotropic Separation for Systems Containing Water

    DEFF Research Database (Denmark)

    Roughton, Brock; Camarda, Kyle V.; Gani, Rafiqul

    fraction of water at the azeotrope is less than 30%. For promising ionic liquid candidates, the extractive distillation processes were designed using a reverse simulation approach and characterized in terms of the driving force (calculated from the predicted vapor-liquid equilibria) that corresponds to the...... optimal design of the separation process (in terms of number of stages, feed plate location, energy used, solvent loss, environmental impact, etc.). To ensure the feasibility of ionic liquids to be used as industrial entrainers, a correlation was also made relating molecular structure to thermal...... decomposition temperature. For any new synthesis-design problem involving aqueous azeotropes, all it now requires is to find the azeotropic composition of water and based on it, to identify an appropriate ionic liquid. Then the driving force is calculated for the azeotrope ionic liquid and based on it, the...

  12. Ionic-Liquid Based Separation of Azeotropic Mixtures

    DEFF Research Database (Denmark)

    Kulajanpeng, Kusuma; Suriyapraphadilok, Uthaiporn; Gani, Rafiqul

    2014-01-01

    methodology for the screening of ionic liquids (ILs) as entrainers for ILs-based separation processes in binary aqueous azeotropic systems (e.g., water + ethanol and water + isopropanol) is presented. Ionic liquids as entrainers were first screened based on a combination of criteria such as...... stability, toxicity, and environmental impacts of the ILs. A Hildebrand solubility parameter group contribution model for ILs is highlighted to screen the miscibility of the ILs with the target solute component which was considered as a key target property to further screen the candidates from the previous...... minimum concentration of the ILs required to break the given azeotrope, the best ILs as entrainers for water + ethanol and water + isopropanol azeotropic mixtures were [C1MIM][DMP] and [C2MIM][N(CN)2], respectively....

  13. Stable and water-tolerant ionic liquid ferrofluids.

    Science.gov (United States)

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

    2011-03-01

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

  14. Estimating the Aqueous Solubility of Pharmaceutical Hydrates.

    Science.gov (United States)

    Franklin, Stephen J; Younis, Usir S; Myrdal, Paul B

    2016-06-01

    Estimation of crystalline solute solubility is well documented throughout the literature. However, the anhydrous crystal form is typically considered with these models, which is not always the most stable crystal form in water. In this study, an equation which predicts the aqueous solubility of a hydrate is presented. This research attempts to extend the utility of the ideal solubility equation by incorporating desolvation energetics of the hydrated crystal. Similar to the ideal solubility equation, which accounts for the energetics of melting, this model approximates the energy of dehydration to the entropy of vaporization for water. Aqueous solubilities, dehydration and melting temperatures, and log P values were collected experimentally and from the literature. The data set includes different hydrate types and a range of log P values. Three models are evaluated, the most accurate model approximates the entropy of dehydration (ΔSd) by the entropy of vaporization (ΔSvap) for water, and utilizes onset dehydration and melting temperatures in combination with log P. With this model, the average absolute error for the prediction of solubility of 14 compounds was 0.32 log units. PMID:27238488

  15. A spectroscopic and computational study of Al(III) complexes in cryolite melts: Effect of cation nature

    OpenAIRE

    Nazmutdinov, Renat R.; Zinkicheva, Tamara T.; Vassiliev, Sergey Yu.; Glukhov, Dmitrii V.; Tsirlina, Galina A.; Probst, Michael

    2013-01-01

    Lithium, sodium and potassium cryolite melts are probed by Raman spectroscopy in a wide range of the melt composition. The experimental data demonstrate a slight red shift of main peaks and a decrease of their half-widths in the row Li+, Na+, K+. Quantum chemical modelling of the systems is performed at the density functional theory level. The ionic environment is found to play a crucial role in the energy of fluoroaluminates. Potential energy surfaces describing the formation/dissociation of...

  16. TOUGHREACT Testing in High Ionic Strength Brine Sandstone Systems

    International Nuclear Information System (INIS)

    Deep saline formations and oil and gas reservoirs often contain concentrated brine solutions of ionic strength greater than 1 (I > 1 M). Geochemical modeling, involving high ionic strength brines, is a challenge. In the original TOUGHREACT code (Xu et al., 2004; Xu et al., 2006), activity coefficients of charged aqueous species are computed using an extended Debye-Huckel (DH) equation and parameters derived by Helgeson et al. (1981). The DH model can deal with ionic strengths from dilute to moderately saline water (up to 6 molal for an NaCl-dominant solution). The equations implemented for the DH model are presented in Appendix A. During the course of the Yucca Mountain project, a Pitzer ion-interaction model was implemented into TOUGHREACT. This allows the application of this simulator to problems involving much more concentrated aqueous solutions, such as those involving geochemical processes in and around high-level nuclear waste repositories where fluid evaporation and/or boiling is expected to occur (Zhang et al., 2007). The Pitzer ion-interaction model, which we refer to as the Pitzer virial approach, and associated ion-interaction parameters have been applied successfully to study non-ideal concentrated aqueous solutions. The formulation of the Pitzer model is presented in Appendix B; detailed information can be founded in Zhang et al. (2007). For CO2 geological sequestration, the Pitzer ion-interaction model for highly concentrated brines was incorporated into TOUGHREACT/ECO2N, then was tested and compared with a previously implemented extended Debye-Hueckel (DH) ion activity model. The comparison was made through a batch geochemical system using a Gulf Coast sandstone saline formation

  17. Novel room temperature ionic liquid for fluorescence enhancement of Eu3+ and Tb3+

    International Nuclear Information System (INIS)

    The newly prepared ionic liquid, 1-butyl-3-methylimidazolium benzoate, ([bmim][BA]), was found to enhance the fluorescence of Eu3+ and Tb3+. The fluorescence enhancement resulted from a sensitization of the lanthanide fluorescence by the benzoate anion of the ionic liquid, [bmim][BA], and a reduction in the non-radiative channels in the non-aqueous environment provided by the ionic liquid. However, the fluorescence enhancement of the lanthanides in the ionic liquid was limited due to the operation of the inner filter effect, which resulted from the strong absorption of the benzoate. The inner filter effect was minimized by observing the Eu3+ fluorescence using a front face geometry and also by diluting the lanthanide-[bmim][BA] system, using another ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([bmim][Tf2N]), as a solvent. In the case of Tb3+, the emission from the lanthanide was masked by the strong emission from the ionic liquid in the region 450-580 nm. The long lived Tb3+ emission was therefore observed using delayed gated detection, where an appropriate delay was used to discriminate against the short lived emission from the ionic liquid. The large fluorescence enhancement due to ligand sensitized fluorescence observed with [bmim][BA] diluted in [bmim][Tf2N], leads to nanomolar detection of the lanthanides. This is, to the best of our knowledge, the first report of an ionic liquid being employed for ligand sensitized fluorescence enhancement of lanthanides. - Research highlights: →The use of an ionic liquid to enhance the fluorescence of lanthanides, Eu3+ and Tb3+ is discussed in this paper. → This study represents the first report of the use of a tailored ionic liquid for the purposes of fluorescence enhancement. → The fluorescence enhancement is achieved both a process of ligand sensitization, as well as reducing the non-radiative decay channels. → The first point is achieved by the use of an anion capable of ligand

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

    Institute of Scientific and Technical Information of China (English)

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

    2012-01-01

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

  19. Special Report: Solid Ionic Conductors.

    Science.gov (United States)

    Shriver, Duward F.; Farrington, Gregory C.

    1985-01-01

    Solid ionic conductors are unusual materials that may find valuable applications in devices ranging from high-energy density batteries to lasers. The nature of these materials and their potential uses are discussed. (JN)

  20. Novel approaches to ionic chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Dasgupta, P.K.

    1990-11-01

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

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

    Science.gov (United States)

    Frischknecht, Amalie L.

    2012-02-01

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

  2. Influence of the melt structure on the electrodeposition of molybdenum

    International Nuclear Information System (INIS)

    The influence of ionic structure molten salts used as electrolyte in electrodeposition of molybdenum has been studied by voltammetric and chronopentiometric method. It was found that during the dissolution for potassium molybdenum in KF-B2O3 electrolyte, both electrochemically active and inactive, molybdenum containing species have been created in the melt. The electrochemically active molybdenum compound was created by a chemical reaction with boron containing constituents in the melt. Electrochemically inactive molybdenum species were created by the reaction of K2MoO4 with fluoride anions. Using the complex thermodynamics and physico-chemical analysis it was found that the investigated electrolyte KF-K2MoO4-B2O3 the electrochemical process is significantly facilitated by the formation of complex heteropolyanions with lowered symmetry of coordination sphere. (author)

  3. Holographic meson melting

    International Nuclear Information System (INIS)

    The plasma phase at high temperatures of a strongly coupled gauge theory can be holographically modelled by an AdS black hole. Matter in the fundamental representation and in the quenched approximation is introduced through embedding D7-branes in the AdS-Schwarzschild background. Low spin mesons correspond to the fluctuations of the D7-brane world volume. As is well known by now, there are two different kinds of embeddings, either reaching down to the black hole horizon or staying outside of it. In the latter case the fluctuations of the D7-brane world volume represent stable low spin mesons. In the plasma phase we do not expect mesons to be stable but to melt at sufficiently high temperature. We model the late stages of this meson melting by the quasinormal modes of D7-brane fluctuations for the embeddings that do reach down to the horizon. The inverse of the imaginary part of the quasinormal frequency gives the typical relaxation time back to equilibrium of the meson perturbation in the hot plasma. We briefly comment on the possible application of our model to quarkonium suppression

  4. Preparation and characterization of two-phase melt systems of lidocaine.

    Science.gov (United States)

    Kang, L; Jun, H W; Mani, N

    2001-07-01

    The melting point of lidocaine was significantly lowered when mixed with thymol and/or aqueous ethanol. Mixtures of lidocaine and thymol at ratios within the range of 30:70-70:30 (w:w) became homogeneous oils at 25 degrees C. In a pH 9.2 carbonate buffer containing 25% ethanol, lidocaine (5%, w:w) also liquefied at 25 degrees C. The studies led to the development of novel two-phase melt systems of lidocaine (TMS) which consisted of a highly concentrated oil phase of lidocaine and an alcoholic aqueous phase. A compositional phase diagram showed that in aqueous dispersions of lidocaine, concurrent use of thymol and ethanol depressed the melting point of lidocaine more effectively than when they were used individually. Both thymol and aqueous ethanol were necessary as melting point depressing agents to achieve the highest possible lidocaine concentration of 87% (w:w) in the oil phase of a TMS at 25 degrees C. Containing an internal oil phase and an external aqueous phase at ambient temperature, such a TMS can be readily formulated into topical O/W cream after addition of proper surfactants and thickening agents. In an anesthetic activity test using mouse tail-flick model, a 5% lidocaine cream prepared was highly effective as shown by the prolonged latency time of the mice to a heat stimulus as compared with a placebo (P<0.05). PMID:11404030

  5. Studies in solid state ionics

    International Nuclear Information System (INIS)

    Studies performed over 10 years by the high temperature chemistry group are reviewed. Attention was paid to different aspects of ionic solids from the point of view of practical as well as theoretical needs of nuclear technology. Thus ceramic fuel compound like uranates, urania-thoria system, solid electrolytes based on oxides and ionics transformations were studied under reactor irradiation. (author) 13 figs., 3 tabs., 46 refs

  6. Ionic Liquid Epoxy Resin Monomers

    Science.gov (United States)

    Paley, Mark S. (Inventor)

    2013-01-01

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

  7. Electrochemical Depositions in Ionic Liquids

    OpenAIRE

    De Vreese, Peter

    2013-01-01

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

  8. Ionic liquids within polymer matrices

    Czech Academy of Sciences Publication Activity Database

    Matějka, Libor; Donato, Ricardo Keitel; Schrekker, H. S.

    Gargnano, Lago di Garda : European Polymer Federation, 2013. s. 10. [EUPOC 2013 on Polymers & Ionic Liquids. 01.09.2013-05.09.2013, Gargnano, Lago di Garda] R&D Projects: GA ČR GAP108/12/1459 Grant ostatní: AV ČR(CZ) M200501203 Institutional support: RVO:61389013 Keywords : ionic liquids * nanocomposite * epoxide Subject RIV: CD - Macromolecular Chemistry

  9. Electrodeposition of metals from non-aqueous solutions

    International Nuclear Information System (INIS)

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

  10. Melting of Ice under Pressure

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-07-31

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

  11. Co-settling of Chromite and Sulfide Melt Droplets and Trace Element Partitioning between Sulfide and Silicate Melts

    Science.gov (United States)

    Manoochehri, S.; Schmidt, M. W.; Guenther, D.

    2013-12-01

    both, the nucleation of newly formed sulfide droplets and the interconnectivity of separate droplets. The interfacial energies between sulfide melt and silicate or oxide crystals is even higher than for silicate melt, consequently in experiments with chromite, sulfide segregation is even more hindered. Partition coefficients of 50 elements between a sulfide and a silicate melt are determined as a function of differing temperature between 1250 - 1380 °C. As a proxy to investigate the bond strength of network modifier cations, the relation between the partition coefficients and ionic potentials of different groups of elements has been determined.

  12. Novel non-aqueous nano-composite electrolyte membranes

    Energy Technology Data Exchange (ETDEWEB)

    Singh, M.; Missan, H.P.S. [West Indies Univ., St. Augustine (Trinidad and Tobago). Dept. of Physics

    2009-07-01

    Fuel cell technology is increasingly being considered as a replacement for non-renewable energy sources. However, the use of commercial perfluorinated sulfonated membranes such as Nafion increases the cost of fuel cells. This paper discussed new and novel non-aqueous proton conducting membranes based on an ionic liquid ternary system containing nano-tubular inorganic oxides. Experiments conducted to demonstrate the system showed that a high non-aqueous ionic conductivity of 10-2 S per cm at temperatures up to 150 degrees can be obtained. Thermographic analyses determined that the membranes maintain stability up to temperatures of 250 degrees C. It was concluded that the addition of a nano-tubular composite phase optimize membrane morphology and increase thermal stability.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-08-10

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

  14. Acidic aqueous uranium electrodeposition for target fabrication

    International Nuclear Information System (INIS)

    Direct irradiation of targets inside nuclear research or multiple purpose reactors is a common route to produce 99Mo-99mTc radioisotopes. The electroplating of low enriched uranium over nickel substrate might be a potential alternative to produce targets of 235U. The electrochemistry of uranium at low temperature might be beneficial for an alternative route to produce 99Mo irradiation LEU targets. Electrodeposition of uranium can be made using ionic and aqueous solutions producing uranium oxide deposits. The performance of uranium electrodeposition is relatively low because a big competition with H2 evolution happens inside the window of electrochemical reduction potential. This work explores possibilities of electroplating uranium as UO22+ (Uranium-VI) in order to achieve electroplating uranium in a sufficient amount to be commercially irradiated in the future Brazilian RMB reactor. Electroplated nickel substrate was followed by cathodic current electrodeposition from aqueous UO2(NO3)2 solution. EIS tests and modeling showed that a film formed differently in the three tested cathodic potentials. At the lower level, (-1.8V) there was an indication of a double film formation, one overlaying the other with ionic mass diffusion impaired at the interface with nickel substrate as showed by the relatively lower admittance of Warburg component. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Deen [ORNL; Wu, Jianzhong [ORNL

    2013-01-01

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

  16. MULTIPLE MELTING IN NYLON 1010

    Institute of Scientific and Technical Information of China (English)

    FU Shuren; CHEN Taoyung

    1983-01-01

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

  17. Melting behavior of yttrium orthovanadate

    International Nuclear Information System (INIS)

    When YVO4 melts at 18100C, it decomposes to form YVO3, a black semi-conducting compound. Between about 15000C and its melting point, YVO4 also reacts to form Y8V2O17 plus V2O5. The melt actually consists of a ternary system whose composition changes with time. Reoxidation of YVO3 to YVO4 can be accomplished below the melting point by annealing in oxygen. The difficulty in obtaining high-quality optical crystals of YVO4 by Czrochralski growth is thus explained. (U.S.)

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

    OpenAIRE

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

    2016-01-01

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

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

    International Nuclear Information System (INIS)

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

  20. Melting method for miscellaneous radioactive solid waste and melting furnace

    International Nuclear Information System (INIS)

    A vessel containing miscellaneous solid wastes is inserted in a crucible having a releasable material on the inner surface, they are induction-heated from the outside of the crucible by way of low temperature heating coils to melt low melting point materials in the miscellaneous wastes within a temperature range at which the vessel does not melt. Then, they are induction-heated by way of high temperature heating coils to melt the vessel and not yet melted materials, those molten materials are cooled, solidified molten material and the releasable material are taken out, and then the crucible is used again. Then, the crucible can be used again, so that it can be applied to a large scaled melting furnace which treats wastes by a unit of drum. In addition, since the cleaning of the used crucible and the application of the releasable material can be conducted without interrupting the operation of the melting furnace, the operation cycle of the melting furnace can be shortened. (N.H.)

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

    Science.gov (United States)

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

    2016-01-15

    A new approach for ionic liquid based enzyme-assisted extraction (ILEAE) of chlorogenic acid (CGA) from Eucommia ulmoides is presented in which enzyme pretreatment was used in ionic liquids aqueous media to enhance extraction yield. For this purpose, the solubility of CGA and the activity of cellulase were investigated in eight 1-alkyl-3-methylimidazolium ionic liquids. Cellulase in 0.5 M [C6mim]Br aqueous solution was found to provide better performance in extraction. The factors of ILEAE procedures including extraction time, extraction phase pH, extraction temperatures and enzyme concentrations were investigated. Moreover, the novel developed approach offered advantages in term of yield and efficiency compared with other conventional extraction techniques. Scanning electronic microscopy of plant samples indicated that cellulase treated cell wall in ionic liquid solution was subjected to extract, which led to more efficient extraction by reducing mass transfer barrier. The proposed ILEAE method would develope a continuous process for enzyme-assisted extraction including enzyme incubation and solvent extraction process. In this research, we propose a novel view for enzyme-assisted extraction of plant active component, besides concentrating on enzyme facilitated cell wall degradation, focusing on improvement of bad permeability of ionic liquids solutions. PMID:26709302

  2. Ionic strength dependence of stability constants, complexation of Molybdenum(V I) with EDTA

    International Nuclear Information System (INIS)

    The stability constant of Mo (Vi) complexes with EDTA in aqueous solution has been determined by various authors using different techniques, but according to literature, no work has been reported on ionic strength dependence of these complexes. The present work describes the complexation of Mo (Vi) with EDTA in an ionic strength range of 0.1 to 1.0 moldm-3sodium perchlorate at 25digC. The complexation of molybdenum (Vi) with EDTA was investigated in aqueous solution ranging in ph from 5 to 7 using UV spectrophotometric techniques. The composition of the complex was determined by the continuous variations method. It was shown that molybdenum (Vi) forms a 2:1 complex with EDTA of the type (MoO3)2L-4at ph =5.5 The parameters that define the dependence on ionic strength were analyzed with the aim of obtaining further information regarding to their variation as a function of the charges involved in the complex reaction. Moreover, a Debye-Huckel type equation makes it possible to estimate a stability constant at a fixed ionic strength when its value is known at another ionic media in the range of 0.13. Therefore the evaluation may make a significant contribution solving many analytical and speciation problems

  3. Comparing two tetraalkylammonium ionic liquids. II. Phase transitions

    Science.gov (United States)

    Lima, Thamires A.; Paschoal, Vitor H.; Faria, Luiz F. O.; Ribeiro, Mauro C. C.; Ferreira, Fabio F.; Costa, Fanny N.; Giles, Carlos

    2016-06-01

    Phase transitions of the ionic liquids n-butyl-trimethylammonium bis(trifluoromethanesulfonyl)imide, [N1114][NTf2], and methyl-tributylammonium bis(trifluoromethanesulfonyl)imide, [N1444][NTf2], were investigated by differential scanning calorimetry (DSC), X-ray diffraction (XRD) measurements, and Raman spectroscopy. XRD and Raman spectra were obtained as a function of temperature at atmospheric pressure, and also under high pressure at room temperature using a diamond anvil cell (DAC). [N1444][NTf2] experiences glass transition at low temperature, whereas [N1114][NTf2] crystallizes or not depending on the cooling rate. Both the ionic liquids exhibit glass transition under high pressure. XRD and low-frequency Raman spectra provide a consistent physical picture of structural ordering-disordering accompanying the thermal events of crystallization, glass transition, cold crystallization, pre-melting, and melting. Raman spectra in the high-frequency range of some specific cation and anion normal modes reveal conformational changes of the molecular structures along phase transitions.

  4. Transformation of acidic poorly water soluble drugs into ionic liquids.

    Science.gov (United States)

    Balk, Anja; Wiest, Johannes; Widmer, Toni; Galli, Bruno; Holzgrabe, Ulrike; Meinel, Lorenz

    2015-08-01

    Poor water solubility of active pharmaceutical ingredients (API) is a major challenge in drug development impairing bioavailability and therapeutic benefit. This study is addressing the possibility to tailor pharmaceutical and physical properties of APIs by transforming these into tetrabutylphosphonium (TBP) salts, including the generation of ionic liquids (IL). Therefore, poorly water soluble acidic APIs (Diclofenac, Ibuprofen, Ketoprofen, Naproxen, Sulfadiazine, Sulfamethoxazole, and Tolbutamide) were converted into TBP ILs or low melting salts and compared to the corresponding sodium salts. Free acids and TBP salts were characterized by NMR and IR spectroscopy, DSC and XRPD, DVS and dissolution rate measurements, release profiles, and saturation concentration measurements. TBP salts had lower melting points and glass transition temperatures and dissolution rates were improved up to a factor of 1000 as compared to the corresponding free acid. An increase in dissolution rates was at the expense of increased hygroscopicity. In conclusion, the creation of TBP ionic liquids or solid salts from APIs is a valuable concept addressing dissolution and solubility challenges of poorly water soluble acidic compounds. The data suggested that tailor-made counterions may substantially expand the formulation scientist's armamentarium to meet challenges of poorly water soluble drugs. PMID:25976317

  5. Excluded volume and ion-ion correlation effects on the ionic atmosphere around B-DNA: Theory, simulations, and experiments

    OpenAIRE

    Ovanesyan, Zaven; Medasani, Bharat; Fenley, Marcia O.; Guerrero-García, Guillermo Iván; Olvera de la Cruz, Mónica; Marucho, Marcelo

    2014-01-01

    The ionic atmosphere around a nucleic acid regulates its stability in aqueous salt solutions. One major source of complexity in biological activities involving nucleic acids arises from the strong influence of the surrounding ions and water molecules on their structural and thermodynamic properties. Here, we implement a classical density functional theory for cylindrical polyelectrolytes embedded in aqueous electrolytes containing explicit (neutral hard sphere) water molecules ...

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

    Science.gov (United States)

    Rout, Alok; Binnemans, Koen

    2016-06-21

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

  7. Dual Ionic and Organic Nature of Ionic Liquids

    Science.gov (United States)

    Shi, Rui; Wang, Yanting

    2016-01-01

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

  8. Sub-0.5 V Highly Stable Aqueous Salt Gated Metal Oxide Electronics

    OpenAIRE

    Sungjun Park; SeYeong Lee; Chang-Hyun Kim; Ilseop Lee; Won-June Lee; Sohee Kim; Byung-Geun Lee; Jae-Hyung Jang; Myung-Han Yoon

    2015-01-01

    Recently, growing interest in implantable bionics and biochemical sensors spurred the research for developing non-conventional electronics with excellent device characteristics at low operation voltages and prolonged device stability under physiological conditions. Herein, we report high-performance aqueous electrolyte-gated thin-film transistors using a sol-gel amorphous metal oxide semiconductor and aqueous electrolyte dielectrics based on small ionic salts. The proper selection of channel ...

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

    OpenAIRE

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

    2011-01-01

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

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

    Science.gov (United States)

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

    2016-07-01

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

  11. Melting and Sintering of Ashes

    DEFF Research Database (Denmark)

    Hansen, Lone Aslaug

    1997-01-01

    of melt in the investigated ashes has been determined as a function of temperature. Ash fusion results have been correlated to the chemical and mineralogical composition of the ashes, to results from a standard ash fusion test and to results from sintering experiments. Furthermore, the ash fusion results...... straw combustion are characterised by a large fraction of KCl and a smaller fraction of K-, Ca-, Al-silicates and quartz. The salt part of these ashes melt in the temperature range from 600-750°C, whereas the silicate part predominantly melts between 1000 and 1200°C. Increasing salt (KCl) content...... in the ashes lead to increased melt fractions in the temperature range 600-750°C.b) Bottom ashes from straw combustion consist purely of silicates, with varying ratios of the quite refractory Al-silicates and quartz to the less refractory K- and Ca-silicates. Bottom ashes melt in the temperature range 800...

  12. A study of redox kinetic in silicate melt

    International Nuclear Information System (INIS)

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

  13. Ionic conductivity in irradiated KCL

    International Nuclear Information System (INIS)

    The ionic conductivity of X and gamma irradiated KCL single crystals has been studied between room temperature and 600 degree centigree. the radiation induced damage resulting in a decrease of the conductivity heals by thermal annealing in two steps which are at about 350 and 550 degree centigree respectively. It has been found that the radiation induced colour centres are not involved in the observed decrease of the ionic conductivity. However. It has been observed that the effects of quenching and plastic deformation on the conductivity of the samples are very similar to the effect induced by irradiation. It is suggested that, samples radiation induced dislocation loops might cause the ionic conductivity decrease observed in irradiated samples. (Author)

  14. Amphiphilic behavior of two phosphonium based ionic liquids.

    Science.gov (United States)

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

    2013-04-01

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

  15. Ionic conducting poly-benzimidazoles

    International Nuclear Information System (INIS)

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

  16. Palladium electrodeposition in 1-butyl-1-methylpyrrolidinium dicyanamide ionic liquid

    International Nuclear Information System (INIS)

    In aqueous solutions, Pd electrodeposition is complicated by hydrogen embrittlement. As an alternative, ionic liquids have been suggested. However, the physical and chemical properties of each ionic liquid are unique. In this work, Pd electrodeposition was investigated on Ni at room temperature in one of the promising air- and water-stable ionic liquids, 1-butyl-1-methylpyrrolidinium dicyanamide ([Bmpyrr][DCA]). The goal of this study was to elucidate kinetics of the Pd electro-reduction in [Bmpyrr][DCA] on Ni using current-time transient method (CTT) and its effect on the structure of the Pd deposits using chronoamperometry. The kinetics of the electrodeposition process was found to be limited by mass transfer. The nucleation and growth mechanism on Ni, extracted from the CTTs and analyzed using Scharifker and Hills model, showed potential dependence; at lower overpotential, the nucleation and growth was progressive that transitioned to instantaneous as the overpotential increased. Pd films obtained after potential holds for 30 min were crack-free and had a surface morphology that was less granular when overpotential increased showing clear potential-dependent nucleation and growth. Evidence of [Bmpyrr][DCA] on the surface of the Pd films was observed using X-ray photoelectron spectroscopy. The Pd films had well-defined crystallinity only after heat treatment at 600 °C

  17. The solvation structures of cellulose microfibrils in ionic liquids.

    Science.gov (United States)

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

    2011-12-01

    The use of ionic liquids for non-derivatized cellulose dissolution promises an alternative method for the thermochemical pretreatment of biomass that may be more efficient and environmentally acceptable than more conventional techniques in aqueous solution. Here, we performed equilibrium MD simulations of a cellulose microfibril in the ionic liquid 1-butyl-3-methylimidazolium chloride (BmimCl) and compared the solute structure and the solute-solvent interactions at the interface with those from corresponding simulations in water. The results indicate a higher occurrence of solvent-exposed orientations of cellulose surface hydroxymethyl groups in BmimCl than in water. Moreover, spatial and radial distribution functions indicate that hydrophilic surfaces are a preferred site of interaction between cellulose and the ionic liquid. In particular, hydroxymethyl groups on the hydrophilic fiber surface adopt a different conformation from their counterparts oriented towards the fiber's core. Furthermore, the glucose units with these solvent-oriented hydroxymethyls are surrounded by the heterocyclic organic cation in a preferred parallel orientation, suggesting a direct and distinct interaction scheme between cellulose and BmimCl. PMID:22179764

  18. Local fields in ionic crystals

    International Nuclear Information System (INIS)

    Local fields arising from the electronic distortion in perfect ionic crystals are described in terms of multipolar excitations. Field factors for the alkali halides and chalcogenide ions are found to differ significantly from the Lorentz value of 4π/3, the correction size following an exponential dependence on the difference in ionic radii. Local fields are only slightly modified by these corrections however, and together with the Clausius-Mossotti relation may be regarded as accurate to within 2% if the Lorentz value is adopted. (author)

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

    Science.gov (United States)

    Yu, Linpo; Chen, George Z

    2016-08-15

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

  20. Electrode reactions of ruthenium–bipyridine complex in amide-type ionic liquids

    International Nuclear Information System (INIS)

    The electrode kinetics of [Ru(bpy)3]3+/[Ru(bpy)3]2+ (bpy = 2,2′-bipyridine) on a platinum electrode was investigated in room-temperature ionic liquids, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide (BMPTFSA), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide (EMITFSA), and 1-butyl-1-methylpyrrolidinium bis(perfluoroethylsulfonyl)amide (BMPBETA) over the temperature range from 25 to 45 °C. The diffusion coefficients of [Ru(bpy)3]2+ and [Ru(bpy)3]3+ were found to be affected not only by the viscosity of ionic liquids but also by the charge density of the complex. The activation energy for the diffusion coefficients of these complexes in the ionic liquids were close to that for the viscosity of the ionic liquids. The standard rate constants of [Ru(bpy)3]3+/[Ru(bpy)3]2+ in BMPTFSA, EMITFSA and BMPBETA were estimated by electrochemical impedance spectroscopy. The standard rate constants in the ionic liquids were estimated to be smaller than those in aqueous and organic electrolytes, probably due to the slow dynamics of the ionic liquids.

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

    OpenAIRE

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

    2011-01-01

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

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

    Science.gov (United States)

    Bhattacharya, Raghu Nath

    2016-01-12

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

  3. Two dimensional superfluidity and melting

    International Nuclear Information System (INIS)

    The author reviews the equilibrium theory of superfluidity and XY magnetism, due in large part to the seminal work of Kosterlitz and Thouless. A dynamic generalization of this theory, with application to third sound in helium films is discussed. The statistical mechanics of two-dimensional melting on both smooth and periodic substrates, is discussed. The dynamic version of the theory is sketched. A theory of melting dynamics is particularly important in interpreting of the experiments on melting and crystallization described earlier. Finally the theory as it applies to anisotropic media including layered materials like smectics, cholesterics, and Rayleigh-Benard convection cells, is discussed. (Auth.)

  4. Glass melting phenomena, their ordering and melting space utilisation

    Czech Academy of Sciences Publication Activity Database

    Němec, Lubomír; Jebavá, Marcela; Dyrčíková, Petra

    2013-01-01

    Roč. 57, č. 4 (2013), s. 275-284. ISSN 0862-5468 R&D Projects: GA TA ČR TA01010844 Institutional support: RVO:67985891 Keywords : glass melting * space utilization * melt flow * phenomena ordering Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 0.434, year: 2013 http://www.ceramics-silikaty.cz/2013/2013_04_275.htm

  5. Ionic Capillary Evaporation in Weakly Charged Nanopores

    OpenAIRE

    Buyukdagli, Sahin; MANGHI, Manoel; Palmeri, John

    2010-01-01

    Using a variational field theory, we show that an electrolyte confined to a neutral cylindrical nanopore traversing a low dielectric membrane exhibits a first-order ionic liquid-vapor pseudo-phase-transition from an ionic-penetration "liquid" phase to an ionic-exclusion "vapor" phase, controlled by nanopore-modified ionic correlations and dielectric repulsion. For weakly charged nanopores, this pseudotransition survives and may shed light on the mechanism behind the rapid switching of nanopor...

  6. Gaseous Hydrocarbon Separations Using Functionalized Ionic Liquids

    OpenAIRE

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

    2016-01-01

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

  7. A spectroscopic and computational study of Al(III) complexes in cryolite melts: Effect of cation nature

    Science.gov (United States)

    Nazmutdinov, Renat R.; Zinkicheva, Tamara T.; Vassiliev, Sergey Yu.; Glukhov, Dmitrii V.; Tsirlina, Galina A.; Probst, Michael

    2013-02-01

    Lithium, sodium and potassium cryolite melts are probed by Raman spectroscopy in a wide range of the melt composition. The experimental data demonstrate a slight red shift of main peaks and a decrease of their half-widths in the row Li+, Na+, K+. Quantum chemical modelling of the systems is performed at the density functional theory level. The ionic environment is found to play a crucial role in the energy of fluoroaluminates. Potential energy surfaces describing the formation/dissociation of certain complex species, as well as model Raman spectra are constructed and compared with those obtained recently for sodium containing cryolite melts (R.R. Nazmutdinov, et al., Spectrochim, Acta A 75 (2010) 1244.). The calculations show that the cation nature affects the geometry of the ionic associates as well as the equilibrium and kinetics of the complexation processes. This enables to interpret both original experimental data and those reported in literature.

  8. Density Measurements of Na2WO4-WO3-ZnO Melts

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

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

  9. Application of Ionic Liquids in Hydrometallurgy

    OpenAIRE

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

    2014-01-01

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

  10. Ionic-Liquid-Tethered Nanoparticles: Hybrid Electrolytes

    KAUST Repository

    Moganty, Surya S.

    2010-10-22

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

  11. Charges at aqueous interfaces: Development of computational approaches in direct contact with experiment

    Czech Academy of Sciences Publication Activity Database

    Vácha, R.; Uhlig, Frank; Jungwirth, Pavel

    Vol. 155. Hoboken : Wiley, 2014 - (Rice, S.; Dinner, A.), s. 69-95 ISBN 978-1-118-75577-8 Institutional support: RVO:61388963 Keywords : aqueous interfaces * computational approaches * electronic structure approach * ionic charges * polarization Subject RIV: CF - Physical ; Theoretical Chemistry

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

    NARCIS (Netherlands)

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

    2010-01-01

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

  13. Lipid processing in ionic liquids

    DEFF Research Database (Denmark)

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

    2007-01-01

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

  14. Green and efficient extraction strategy to lithium isotope separation with double ionic liquids as the medium and ionic associated agent

    International Nuclear Information System (INIS)

    The paper reported a green and efficient extraction strategy to lithium isotope separation. A 4-methyl-10-hydroxybenzoquinoline (ROH), hydrophobic ionic liquid-1,3-di(isooctyl)imidazolium hexafluorophosphate ([D(i-C8)IM][PF6]), and hydrophilic ionic liquid-1-butyl-3-methylimidazolium chloride (ILCl) were used as the chelating agent, extraction medium and ionic associated agent. Lithium ion (Li+) first reacted with ROH in strong alkali solution to produce a lithium complex anion. It then associated with IL+ to form the Li(RO)2IL complex, which was rapidly extracted into the organic phase. Factors for effect on the lithium isotope separation were examined. To obtain high extraction efficiency, a saturated ROH in the [D(i-C8)IM][PF6] (0.3 mol l-1), mixed aqueous solution containing 0.3 mol l-1 lithium chloride, 1.6 mol l-1 sodium hydroxide and 0.8 mol l-1 ILCl and 3:1 were selected as the organic phase, aqueous phase and phase ratio (o/a). Under optimized conditions, the single-stage extraction efficiency was found to be 52 %. The saturated lithium concentration in the organic phase was up to 0.15 mol l-1. The free energy change (ΔG), enthalpy change (ΔH) and entropy change (ΔS) of the extraction process were -0.097 J mol-1, -14.70 J mol K-1 and -48.17 J mol-1 K-1, indicating a exothermic process. The partition coefficients of lithium will enhance with decrease of the temperature. Thus, a 25 deg C of operating temperature was employed for total lithium isotope separation process. Lithium in Li(RO)2IL was stripped by the sodium chloride of 5 mol l-1 with a phase ratio (o/a) of 4. The lithium isotope exchange reaction in the interface between organic phase and aqueous phase reached the equilibrium within 1 min. The single-stage isotope separation factor of 7Li-6Li was up to 1.023 ± 0.002, indicating that 7Li was concentrated in organic phase and 6Li was concentrated in aqueous phase. All chemical reagents used can be well recycled. The extraction strategy offers

  15. METAL MELTS – NANOSTRUCTURED SYSTEMS

    Directory of Open Access Journals (Sweden)

    V. Yu. Stetsenko

    2015-05-01

    Full Text Available On the basis of thermodynamic analysis it is shown that metal melts are the nanostructured systems which consist of phases and atoms nanocrystals. Nanocrystalsmake 97% ofthemeltvolume.

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

    Institute of Scientific and Technical Information of China (English)

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

    2003-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-10-13

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

  18. Activation and stabilization of enzymes in ionic liquids.

    Science.gov (United States)

    Moniruzzaman, Muhammad; Kamiya, Noriho; Goto, Masahiro

    2010-06-28

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2007-01-01

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

  20. Removal of Zn(II) from solutions high ionic strength by adsorbing colloid flotation

    International Nuclear Information System (INIS)

    Removal of zinc(III) from aqueous solutions of relatively high ionic strength was investigated using iron oxyhydroxide and aluminium hydroxide as co precipitant. The main factors affecting the process, such as the type and concentration of collector and inert salt (the ionic strength), the bubbling time, the concentration of both co precipitant and frothier and PH were examined. Removal of >98% were achieved up to 0.4 ionic strength (NaCl) and decreases to about 90% at 0.6 M NaCl on using potassium oleate as a collector, and Aero frothier-77 as a frothier aid. The deleterious effect of the inert salt is more significant with divalent cations or anions than with monovalent ones. The present adsorbing colloid flotation process was applied to concentrate zinc prior to its analysis and to simultaneous removal of heavy metal ions from simulated industrial wastewater for recovery or purification purposes. 8 figs., 3 tabs

  1. Hydrogen production by water electrolysis using tetra-alkyl-ammonium-sulfonic acid ionic liquid electrolytes

    Science.gov (United States)

    Fiegenbaum, Fernanda; Martini, Emilse M.; de Souza, Michèle O.; Becker, Márcia R.; de Souza, Roberto F.

    2013-12-01

    Triethylammonium-propanesulfonic acid tetrafluoroborate (TEA-PS·BF4) is used as an electrolyte in the water electrolysis. The electrolysis of water with this ionic conductor produces high current densities with high efficiencies, even at room temperatures. A system using TEA-PS·BF4 in an electrochemical cell with platinum electrodes has current densities (i) up to 1.77 A cm-2 and efficiencies between 93 and 99% in temperatures ranging from 25 °C to 80 °C. The activation energy observed with TEA-PS·BF4 is ca. 9.3 kJ mol-1, a low value that can be explained by the facilitation of proton transport in the organised aqueous ionic liquid media. The unexpectedly high efficiency of this system is discussed by taking into account the high conductivities associated with the Brönsted and Lewis acidity characteristics associated with these ionic conductive materials.

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

    Institute of Scientific and Technical Information of China (English)

    张延强; 张建敏; 陈玉涣; 张锁江

    2007-01-01

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

  3. Scaleable Clean Aluminum Melting Systems

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-02-15

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

  4. Ionic Force Fields for Electrolytes: Molecular Simulations, Chemical Potentials and Solubilities.

    Czech Academy of Sciences Publication Activity Database

    Nezbeda, Ivo; Moučka, F.; Smith, W.R.

    Ozarow Mazowiecki : Nobell Compressing sp. z o.o, 2015 - (Kosinsky, K.; Urbanczyk, M.; Žerko, S.) ISBN N. [CECAM Workshop Atomistic Simulations in Earth Sciences. Paris (FR), 17.06.2015-19.06.2015] R&D Projects: GA ČR GA15-19542S Institutional support: RVO:67985858 Keywords : simulation * ionic force fields * aqueous electrolytes Subject RIV: CF - Physical ; Theoretical Chemistry http://www.cecam.org/workshop-4-1185.html?presentation_id=14049

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

    OpenAIRE

    Hisae Tateishi-Karimata; Miki Nakano; Naoki Sugimoto

    2014-01-01

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

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

    OpenAIRE

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

    2009-01-01

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

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

    OpenAIRE

    2006-01-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2012-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Kyo-Il Kim

    2009-08-01

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

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

    OpenAIRE

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

    2009-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Hussey, Charles L.

    2004-06-01

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

  12. DNA denaturation in ionic solution

    Science.gov (United States)

    Maity, Arghya; Singh, Amar; Singh, Navin

    2016-05-01

    Salt or cations, present in solution play an important role in DNA denaturation and folding kinetics of DNA helix. In this work we study the thermal melting of double stranded DNA (dsDNA) molecule using Peyrard Bishop Dauxois (PBD) model. We modify the potential of H-bonding between the bases of the complimentary strands to introduce the salt and solvent effect. We choose different DNA sequences having different contents of GC pairs and calculate the melting temperatures. The melting temperature increases logarithmically with the salt concentration of the solution. The more GC base pairs in the chain enhance the stability of DNA chain at a fix salt concentration. The obtained results are in good accordance with experimental findings.

  13. Why are ionic liquids liquid? A simple explanation based on lattice and solvation energies.

    Science.gov (United States)

    Krossing, Ingo; Slattery, John M; Daguenet, Corinne; Dyson, Paul J; Oleinikova, Alla; Weingärtner, Hermann

    2006-10-18

    We have developed a simple and quantitative explanation for the relatively low melting temperatures of ionic liquids (ILs). The basic concept was to assess the Gibbs free energy of fusion (Delta(fus)G) for the process IL(s) --> IL(l), which relates to the melting point of the IL. This was done using a suitable Born-Fajans-Haber cycle that was closed by the lattice (i.e., IL(s) --> IL(g)) Gibbs energy and the solvation (i.e., IL(g) --> IL(l)) Gibbs energies of the constituent ions in the molten salt. As part of this project we synthesized and determined accurate melting points (by DSC) and dielectric constants (by dielectric spectroscopy) for 14 ionic liquids based on four common anions and nine common cations. Lattice free energies (Delta(latt)G) were estimated using a combination of Volume Based Thermodynamics (VBT) and quantum chemical calculations. Free energies of solvation (Delta(solv)G) of each ion in the bulk molten salt were calculated using the COSMO solvation model and the experimental dielectric constants. Under standard ambient conditions (298.15 K and 10(5) Pa) Delta(fus)G degrees was found to be negative for all the ILs studied, as expected for liquid samples. Thus, these ILs are liquid under standard ambient conditions because the liquid state is thermodynamically favorable, due to the large size and conformational flexibility of the ions involved, which leads to small lattice enthalpies and large entropy changes that favor melting. This model can be used to predict the melting temperatures and dielectric constants of ILs with good accuracy. A comparison of the predicted vs experimental melting points for nine of the ILs (excluding those where no melting transition was observed and two outliers that were not well described by the model) gave a standard error of the estimate (s(est)) of 8 degrees C. A similar comparison for dielectric constant predictions gave s(est) as 2.5 units. Thus, from very little experimental and computational data it is

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

    International Nuclear Information System (INIS)

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

  15. Melt eruptions during molten corium concrete interactions

    Science.gov (United States)

    Robb, Kevin Richard

    The melt eruption phenomenon could occur during severe accidents at existing light water nuclear reactors. A postulated beyond-design basis accident includes the melting and relocation of the reactor core onto the concrete basemat of containment. The continually heated melt can reach high temperatures and thermally attack the underlying concrete, MCCI. As the melt cools, a crust forms on the upper surface of the melt pool. Melt eruptions occur when gases from the decomposing concrete passes through channels in the crust ejecting melt onto the upper surface of the crust. The impact of melt eruptions on the coolability of the melt is important when estimating the probability and timing of containment failure. This work focuses on understanding and modeling the melt eruption phenomenon. A model has been developed to predict the amount of melt ejected during melt eruptions. This entrainment model has been verified against an experimental database developed as part of this work. Several phenomena have been identified and modeled which may predict the creation and closure of eruptions sites. The models have been integrated into a MCCI systems code. The new melt eruption model predicted reasonable rates of melt ejection and the number and diameter of eruption sites for a sample simulation of a postulated reactor scale MCCI. Results from the new melt eruption model suggest an ex-vessel core melt under flooded conditions could readily quench.

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

    Institute of Scientific and Technical Information of China (English)

    He Jianfeng; Liu Lan; Yang Guilan; Deng Qinying

    2006-01-01

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

  17. Thermodynamic study on the protonation of glycine in different (water + 1-butyl-3-methylimidazolium tetrafluoroborate) mixed solvents and ionic strengths

    International Nuclear Information System (INIS)

    Highlights: • Dependence of glycine protonation constants on ionic strength. • The ionic strength dependence has been modeled with the extended Debye–Hückel equation. • The ionic liquid behaves like a not significantly interacting salt for % IL > 20%. • Kamlet–Abboud–Taft solvatochromic regression coefficients. -- Abstract: The 1-butyl-3-methylimidazolium tetrafluoroborate, [bmim]BF4, is an ionic liquid when pure. The acid base properties of aqueous solutions of [bmim]BF4 were examined by potentiometric titration. Then, protonation constants of glycine in binary mixtures of water and [bmim]BF4 were determined, from potentiometric titration data obtained at T = 298.2 K and various ionic strengths of sodium chloride (0.25 ⩽ I ⩽ 1.00 mol · dm−3). The ionic strength dependence of the equilibrium constants of glycine was fitted to an extended Debye–Hückel equation to derive ionic strength dependence parameters. Comparison with literature data showed that, even at high concentrations, [bmim]BF4 is similar to the electrolyte [(C2H5)4NI], in that it does not interact significantly with other solutes. Solvatochromic parameters in the binary mixtures of water and [bmim]BF4 have been calculated by using Redlich–Kister equation. Kamlet–Abboud–Taft (KAT) solvatochromic equation allows us to determine the values of calculated protonation constants in different media

  18. Heterogeneous ice nucleation in aqueous solutions: the role of water activity.

    Science.gov (United States)

    Zobrist, B; Marcolli, C; Peter, T; Koop, T

    2008-05-01

    Heterogeneous ice nucleation experiments have been performed with four different ice nuclei (IN), namely nonadecanol, silica, silver iodide and Arizona test dust. All IN are either immersed in the droplets or located at the droplets surface. The IN were exposed to various aqueous solutions, which consist of (NH4)2SO4, H2SO4, MgCl2, NaCl, LiCl, Ca(NO3)2, K2CO3, CH3COONa, ethylene glycol, glycerol, malonic acid, PEG300 or a NaCl/malonic acid mixture. Freezing was studied using a differential scanning calorimeter and a cold finger cell. The results show that the heterogeneous ice freezing temperatures decrease with increasing solute concentration; however, the magnitude of this effect is solute dependent. In contrast, when the results are analyzed in terms of the solution water activity a very consistent behavior emerges: heterogeneous ice nucleation temperatures for all four IN converge each onto a single line, irrespective of the nature of the solute. We find that a constant offset with respect to the ice melting point curve, Deltaaw,het, can describe the observed freezing temperatures for each IN. Such a behavior is well-known for homogeneous ice nucleation from supercooled liquid droplets and has led to the development of water-activity-based ice nucleation theory. The large variety of investigated solutes together with different general types of ice nuclei studied (monolayers, ionic crystals, covalently bound network-forming compounds, and a mixture of chemically different crystallites) underlines the general applicability of water-activity-based ice nucleation theory also for heterogeneous ice nucleation in the immersion mode. Finally, the ice nucleation efficiencies of the various IN, as well as the atmospheric implication of the developed parametrization are discussed. PMID:18363389

  19. Melting and superionic transition of Gd-doped ceria nanocrystals: Molecular dynamics study

    International Nuclear Information System (INIS)

    Molecular dynamics program for simulation of nanocrystals in vacuum, with ionic model approximation, was developed. The use of graphics processor allows us to speed up calculation by two orders of magnitude in comparison with CPU realization. For Ce1−XGdXO2−X/2 system by fitting to experimental data pair interaction potentials were obtained, comparison with existing potential set was carried out. Melting temperature of CeO2 nanocrystal depends on its octahedron diagonal size as Tm(L,nm) = Tm(∞) − (5534 ± 153)⋅L−2. Structural disorder of Ce1−XGdXO2−X/2 nanocrystals (X = 0–0.3) in superionic transition and melting regimes was investigated. Dependences of melting temperature and specific volume change at melting from gadolinium dopant quantity have downward trend. It is shown, that oxygen sublattice disorder (“melting”) in crystallites takes place at about 0.7Tm. The contribution of intrinsic disorder to anion diffusion coefficient in systems with gadolinium dopant was extracted and the presence of superionic transition is shown. Comparison with high-temperature ionic conductivity data was carried out.

  20. Ionic flotation of strontium 89

    International Nuclear Information System (INIS)

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

  1. Aqueous Rechargeable Zinc/Aluminum Ion Battery with Good Cycling Performance.

    Science.gov (United States)

    Wang, Faxing; Yu, Feng; Wang, Xiaowei; Chang, Zheng; Fu, Lijun; Zhu, Yusong; Wen, Zubiao; Wu, Yuping; Huang, Wei

    2016-04-13

    Developing rechargeable batteries with low cost is critically needed for the application in large-scale stationary energy storage systems. Here, an aqueous rechargeable zinc//aluminum ion battery is reported on the basis of zinc as the negative electrode and ultrathin graphite nanosheets as the positive electrode in an aqueous Al2(SO4)3/Zn(CHCOO)2 electrolyte. The positive electrode material was prepared through a simple electrochemically expanded method in aqueous solution. The cost for the aqueous electrolyte together with the Zn negative electrode is low, and their raw materials are abundant. The average working voltage of this aqueous rechargeable battery is 1.0 V, which is higher than those of most rechargeable Al ion batteries in an ionic liquid electrolyte. It could also be rapidly charged within 2 min while maintaining a high capacity. Moreover, its cycling behavior is also very good, with capacity retention of nearly 94% after 200 cycles. PMID:26716878

  2. Ionic liquids for enzymatic sensing

    OpenAIRE

    Fraser, Kevin J.

    2012-01-01

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

  3. Melting in temperature sensitive suspensions

    Science.gov (United States)

    Alsayed, Ahmed M.

    We describe two experimental studies about melting in colloidal systems. In particular we studied melting of 1-dimensional lamellar phases and 3-dimensional colloidal crystals. In the first set of experiments we prepared suspensions composed of rodlike fd virus and the thermosensitive polymer, poly(N-isopropylacrylamide). The phase diagram of this systems is temperature and concentration dependent. Using video microscopy, we directly observed melting of lamellar phases and single lamellae into nematic phase. We found that lamellar phases swell with increasing temperature before melting into the nematic phase. The highly swollen lamellae can be superheated as a result of topological nucleation barriers that slow the formation of the nematic phase. In another set of experiments we prepared colloidal crystals from thermally responsive microgel spheres. The crystals are equilibrium close-packed three-dimensional structures. Upon increasing the temperature slightly above room temperature, particle volume fraction decreased from 0.74 to less than 0.5. Using video microscopy, we observed premelting at grain boundaries and dislocations within bulk colloidal crystals. Premelting is the localized loss of crystalline order at surfaces and defects at sample volume fractions above the bulk melting transition. Particle tracking revealed increased disorder in crystalline regions bordering defects, the amount of which depends on the type of defect, distance from the defect, and particle volume fraction. In total these observations suggest that interfacial free energy is the crucial parameter for premelting in colloidal and in atomic scale crystals.

  4. Transport properties of silicate melts

    Science.gov (United States)

    Ni, Huaiwei; Hui, Hejiu; Steinle-Neumann, Gerd

    2015-09-01

    A quantitative description of the transport properties, diffusivity, viscosity, electrical, and thermal conductivity, of silicate melts is essential for understanding melting-related petrologic and geodynamic processes. We here provide a systematic overview on the current knowledge of these properties from experiments and molecular dynamics simulations, their dependence on pressure, temperature, and composition, atomistic processes underlying them, and physical models to describe their variations. We further establish phenomenological and physical links between diffusivity, viscosity, and electrical conductivity that are based on structural rearrangement in the melt. Neutral molecules and network-modifying cations with low electric field strength display intrinsic diffusivity, which is controlled by the intrinsic properties (size and valence) of the species. By contrast, oxygen and network formers with high field strength show extrinsic diffusivity, which is more sensitive to extrinsic parameters including temperature (T), pressure (P), and melt composition (X). Similar T-P-X dependence of diffusivity and electrical conductivity and their quantitative relation reveal the role of intrinsically diffusing species in electrical transport, while viscosity is tied to the extrinsically diffusing species in a similar way. However, the differences in the structural role and mobility of various atomic species diminish with increasing temperature and/or pressure: all transport processes are increasingly coupled, eventually converging to a uniform rate and mechanism. Accurate comprehension of interatomic interactions and melt structure is vital to fully accounting for the compositional dependence of transport properties, and simple polymerization parameters such as nonbridging oxygen per tetrahedrally coordinated cation are inadequate.

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

    Science.gov (United States)

    Brogan, Alex P S; Hallett, Jason P

    2016-04-01

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

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

    Science.gov (United States)

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

    2011-08-14

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

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

    Science.gov (United States)

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

    2016-06-28

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

  8. Thermodynamics of freezing and melting.

    Science.gov (United States)

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

    2016-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Yuangang Zu

    2012-07-01

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

  10. Challenges in Melt Furnace Tests

    Science.gov (United States)

    Belt, Cynthia

    2014-09-01

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

  11. Skull melting of synthetic minerals

    Energy Technology Data Exchange (ETDEWEB)

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

    1977-12-01

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

  12. Speciation of cobalt-chloride-based ionic liquids and electrodeposition of Co wires

    International Nuclear Information System (INIS)

    Highlights: • Template-free electrodeposition of cobalt nanowires arrays can be achieved from Lewis acidic CoCl2-EMIC ionic liquids. • SEM and TEM images reveal the diameter of the nanowire is around 200 nm, and the XPS data shows that cobalt oxide is formed at the surface of the nanowire. • MALDI-TOF-MS, XAS, and UV-vis spectroscopy results show that the coordination number and the mean Co-Cl bond length are depending on the molar ratio of CoCl2 and EMIC. - Abstract: The speciation and coordination of cobalt-chloride-based ionic liquids with various mole percentages of CoCl2 were investigated using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), X-ray absorption spectroscopy (XAS), ultraviolet-visible absorption spectroscopy, and cyclic voltammetry. The coordination number and the mean Co-Cl bond length decreases with increasing CoCl2 concentration, indicating that various Co(II) chloride compounds such as CoCl42-, Co2Cl5-, and Co3Cl7− are formed depending on the molar ratio of CoCl2 and EMIC in the melt. While the [CoCl4]2− complex formed in the Lewis basic melts and is electrochemically inactive within the electrochemical window of the melt, the other coordination-unsaturated cobalt chloride compounds formed in Lewis acidic melts can be electrochemically reduced to cobalt metal. The template-free electrodeposition of Co nanowires can be achieved from 40-60 mol% and 50-50 mol% CoCl2-EMIC (1-ethyl-3-methylimidazolium chloride) ionic liquids without any additives. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) were used to characterize the surface of the deposits

  13. Ionic liquids: radiation chemistry, solvation dynamics and reactivity patterns

    International Nuclear Information System (INIS)

    dynamics of the excess electron in ILs (which vary over a wide viscosity range) increases the importance of pre-solvated electron reactivity and consequently alters product distributions. Scavenging of the excess electron before it becomes fully solvated is a significant facet of the overall radiation sensitivity of ionic liquids, possibly due to less competition from slower electron solvation processes. Parallel measurements of excess electron solvation processes and emission dynamics (Stokes shift and polarization anisotropy decay) of solvatochromic coumarin-153 show that the reorganization dynamics of ionic liquids extend to much longer timescales (nanoseconds) than in conventional polar solvents (picoseconds). This phenomenon profoundly influences the reactivity and energetics of radiolytically-generated excess electrons. The slow solvation dynamics would also be expected to significantly alter transition state dynamics and provide a potential means to control product distribution. This becomes particularly important for transition states with a very different polarity from the reactants and/or products. Electron reactions with several aromatic acceptors, acids, and oxygen were measured in (MeBu3N+)(NTf2-). Rate constants for solvated electron capture by benzophenone, pyrene and phenanthrene were on the order of 1.6x108 M-1·s-1, typically 100 times slower than observed in conventional polar solvents. The reactions of hydrogen atoms with several of the same reactants were measured in the same ionic liquid. H-atoms react very rapidly with pyrene and phenanthrene (∼3 x 109 L·mol-1·s-1) to form H-adduct radicals. The H-atom rate constants are similar to the values measured or estimated for the same reactions in aqueous solutions. The H-atom reactions with the aromatic hydrocarbons must be diffusion-controlled, but are faster than diffusion-controlled reactions for solvated electrons in the same ionic liquid. The results indicate that the diffusion rate for the

  14. Melting of metasomatized peridotite at 4-6 GPa and up to 1200 °C: an experimental approach

    Science.gov (United States)

    Kessel, R.; Pettke, T.; Fumagalli, P.

    2015-04-01

    The phase assemblages and compositions in a K-bearing lherzolite + H2O system are determined between 4 and 6 GPa and 850-1200 °C, and the melting reactions occurring at subarc depth in subduction zones are constrained. Experiments were performed on a rocking multi-anvil apparatus. The experiments had around 16 wt% water content, and hydrous melt or aqueous fluid was segregated and trapped in a diamond aggregate layer. The compositions of the aqueous fluid and hydrous melt phases were measured using the cryogenic LA-ICP-MS technique. The residual lherzolite consists of olivine, orthopyroxene, clinopyroxene, and garnet, while diamond (C) is assumed to be inert. Hydrous and alkali-rich minerals were absent from the run products due to preferred dissolution of K2O (and Na2O) to the aqueous fluid/hydrous melt phases. The role of phlogopite in melting relations is, thus, controlled by the water content in the system: at the water content of around 16 wt% used here, phlogopite is unstable and thus does not participate in melting reactions. The water-saturated solidus, i.e., the first appearance of hydrous melt in the K-lherzolite composition, is located between 900 and 1000 °C at 4 GPa and between 1000 and 1100 °C at 5 and 6 GPa. Compositional jumps between hydrous melt and aqueous fluid at the solidus include a significant increase in the total dissolved solids load. All melts/fluids are peralkaline and calcium-rich. The melting reactions at the solidus are peritectic, as olivine, clinopyroxene, garnet, and H2O are consumed to generate hydrous melt plus orthopyroxene. Our fluid/melt compositional data demonstrate that the water-saturated hybrid peridotite solidus lies above 1000 °C at depths greater than 150 km and that the second critical endpoint is not reached at 6 GPa for a K2O-Na2O-CaO-FeO-MgO-Al2O3-SiO2-H2O-Cr2O3(-TiO2) peridotite composition.

  15. Fluidic Dielectrophoresis of Aqueous Electrical Interfaces

    Science.gov (United States)

    Gagnon, Zachary

    2014-11-01

    To date, alternating current (AC) electric fields have been exploited to dielectrophoretically manipulate bubbles, liquid drops, particles, biomolecules and cells. Research and applications in this area, however, has been primarily limited to the interfaces formed between two immiscible metal-liquid, particle-liquid, or gas-liquid surfaces on particles. The influence of AC electric fields across aqueous liquid-liquid interfaces remains relatively unexplored. Fundamentally, many electrokinetic phenomena arise from discontinuities in ionic flux and charge accumulation at electrical interfaces, and here I explore the influence of AC electric fields on the electrical interface created between two aqueous liquids with disparaging electrical properties Using a microfluidic channel with embedded electrodes, two fluid streams - one with a greater electrical conductivity, the other a greater dielectric constant - were made to flow side-by-side. An AC electric field was applied across the flow channel and fluid was observed to displace across the phase interface. The displacement direction is AC frequency dependent, and is attributed to the Maxwell-Wagner interfacial polarization at the liquid-liquid electrical interface. At low AC frequency, below the interfacial charge relaxation time, the high conductive stream is observed to displace into the high dielectric stream. Above this frequency, the direction of liquid injection reverses, and the high dielectric stream injects into the high conductivity stream. An analytical model is presented for this liquid crossover frequency, and applied towards biosensing applications.

  16. Corrosion problems with aqueous coolants, final report

    Energy Technology Data Exchange (ETDEWEB)

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

    1980-04-11

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

  17. Ionic Liquids: Green Solvents for Chemical Processing

    OpenAIRE

    Antonia Pérez de los Ríos; Angel Irabien; Frank Hollmann; Francisco José Hernández Fernández

    2013-01-01

    Ionic liquids are organic salts, usually consisting of an organic cation and a polyatomic inorganic anion, which are liquid under 100∘ C. The most relevant properties of ionic liquids are their almost negligible vapour pressure. Furthermore, their physical and chemical properties can be fine-tuned by the adequate selection of the cation and anion constituents. Ionic liquids have been recognized as environmental benign alternative to volatile organic solvents. Applicati...

  18. Photochemical Schiemann Reaction in Ionic Liquids

    OpenAIRE

    Heredia-Moya, Jorge; Kirk, Kenneth L.

    2007-01-01

    Photochemical Schiemann reactions of imidazole derivatives 1 and 4 were carried out in 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid [bmim][BF4] as solvent. The effects of temperature, co-solvent and wavelength on the rate of the reaction and product yield were examined. The use of ionic liquid increases the yield of the photochemical fluorodediazoniation reaction of 2 at 0°C. Careful temperature control is necessary to minimize the photodecomposition of the ionic liquid in order...

  19. Rearrangement reactions in ionic liquid media

    OpenAIRE

    Sarmīte Katkeviča

    2009-01-01

    ABSTRACT Ph.D. theses „Rearrangement reactions in ionic liquid media” are devoted to the subject that has gained great actuality and large popularity today - ionic liquids. The research about three different by reaction mechanisms organic transformations – Fries, Beckmann and Claisen rearrangement reactions in ionic liquid media is discussed in the thesis. The novelty of the research is connected with the replacement of organic solvents with environmentally friendly material...

  20. Quantized Friction across Ionic Liquid Thin Films

    OpenAIRE

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

    2013-01-01

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

  1. Novel thiosalicylate-based ionic liquids for heavy metal extractions.

    Science.gov (United States)

    Leyma, Raphlin; Platzer, Sonja; Jirsa, Franz; Kandioller, Wolfgang; Krachler, Regina; Keppler, Bernhard K

    2016-08-15

    This study aims to develop novel ammonium and phosphonium ionic liquids (ILs) with thiosalicylate (TS) derivatives as anions and evaluate their extracting efficiencies towards heavy metals in aqueous solutions. Six ILs were synthesized, characterized, and investigated for their extracting efficacies for cadmium, copper, and zinc. Liquid-liquid extractions of Cu, Zn, or Cd with ILs after 1-24h using model solutions (pH 7; 0.1M CaCl2) were assessed using flame atomic absorption spectroscopy (F-AAS). Phosphonium-based ILs trihexyltetradecylphosphonium 2-(propylthio)benzoate [P66614][PTB] and 2-(benzylthio)benzoate [P66614][BTB] showed best extraction efficiency for copper and cadmium, respectively and zinc was extracted to a high degree by [P66614][BTB] exclusively. PMID:27131456

  2. Improved Ionic Liquids as Space Lubricants Project

    Data.gov (United States)

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

  3. Supported Ionic Liquid Phase (SILP) catalysis

    DEFF Research Database (Denmark)

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

    2006-01-01

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

  4. Lithium hydride near melting point

    International Nuclear Information System (INIS)

    The mechanical stability of LiH crystal is studied in this paper. The instability temperature Te is found to lie above the observed melting point, in accord with computer simulation results of other materials. Several other features of LiH both in the solid and molten states are also discussed. (author). 22 refs, 4 figs

  5. Unique role of ionic liquid [bmin][BF 4] during curcumin-surfactant association and micellization of cationic, anionic and non-ionic surfactant solutions

    Science.gov (United States)

    Patra, Digambara; Barakat, Christelle

    2011-09-01

    Hydrophilic ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroburate, modified the properties of aqueous surfactant solutions associated with curcumin. Because of potential pharmaceutical applications as an antioxidant, anti-inflammatory and anti-carcinogenic agent, curcumin has received ample attention as potential drug. The interaction of curcumin with various charged aqueous surfactant solutions showed it exists in deprotonated enol form in surfactant solutions. The nitro and hydroxyl groups of o-nitrophenol interact with the carbonyl and hydroxyl groups of the enol form of curcumin by forming ground state complex through hydrogen bonds and offered interesting information about the nature of the interactions between the aqueous surfactant solutions and curcumin depending on charge of head group of the surfactant. IL[bmin][BF 4] encouraged early formation of micelle in case of cationic and anionic aqueous surfactant solutions, but slightly prolonged micelle formation in the case of neutral aqueous surfactant solution. However, for curcumin IL [bmin][BF 4] favored strong association (7-fold increase) with neutral surfactant solution, marginally supported association with anionic surfactant solution and discouraged (˜2-fold decrease) association with cationic surfactant solution.

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

    OpenAIRE

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

    2014-01-01

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

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

    Science.gov (United States)

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

    2016-03-21

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

  8. The molecular structure of melts along the carbonatite-kimberlite-basalt compositional joint: CO2 and polymerisation

    Science.gov (United States)

    Moussallam, Yves; Florian, Pierre; Corradini, Dario; Morizet, Yann; Sator, Nicolas; Vuilleumier, Rodolphe; Guillot, Bertrand; Iacono-Marziano, Giada; Schmidt, Burkhard C.; Gaillard, Fabrice

    2016-01-01

    Transitional melts, intermediate in composition between silicate and carbonate melts, form by low degree partial melting of mantle peridotite and might be the most abundant type of melt in the asthenosphere. Their role in the transport of volatile elements and in metasomatic processes at the planetary scale might be significant yet they have remained largely unstudied. Their molecular structure has remained elusive in part because these melts are difficult to quench to glass. Here we use FTIR, Raman, 13C and 29Si NMR spectroscopy together with First Principle Molecular Dynamic (FPMD) simulations to investigate the molecular structure of transitional melts and in particular to assess the effect of CO2 on their structure. We found that carbon in these glasses forms free ionic carbonate groups attracting cations away from their usual 'depolymerising' role in breaking up the covalent silicate network. Solution of CO2 in these melts strongly modifies their structure resulting in a significant polymerisation of the aluminosilicate network with a decrease in NBO/Si of about 0.2 for every 5 mol% CO2 dissolved. This polymerisation effect is expected to influence the physical and transport properties of transitional melts. An increase in viscosity is expected with increasing CO2 content, potentially leading to melt ponding at certain levels in the mantle such as at the lithosphere-asthenosphere boundary. Conversely an ascending and degassing transitional melt such as a kimberlite would become increasingly fluid during ascent hence potentially accelerate. Carbon-rich transitional melts are effectively composed of two sub-networks: a carbonate and a silicate one leading to peculiar physical and transport properties.

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

    Science.gov (United States)

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

    2016-03-01

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

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

    International Nuclear Information System (INIS)

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

  11. Screening of non-Ionic Surfactant for Enhancing Biobutanol Production.

    Science.gov (United States)

    Dhamole, Pradip B; Mane, Ravindra G; Feng, Hao

    2015-11-01

    This work deals with finding a suitable non-ionic surfactant which has high butanol capturing capacity and can be separated at a temperature close to room temperature and does not extract any intermediates or substrate (i.e., glucose). Importantly, it should be biocompatible, and its separation from the aqueous phase is not affected by other fermentation products. Hence, a pool of non-ionic Pluronic surfactants (L31, L61, L62D, L62LF, L62, L81, L92, L101, L121, L64, P65, P84, P104, P105) were selected for the study. Screening of the surfactant was done based on its hydrophile-lipophile balance (HLB) value, butanol capturing capacity (BCC), and cloud point temperature. Among the various surfactant investigated, L62D captured maximum amount of butanol (0.68 g/g of surfactant). Also, the cloud point temperature of L62D is close to room temperature (28.7 °C). Biocompatibility studies were carried out by conducting fermentation in presence of 3% L62D which resulted in 148% increase in butanol production as compared to control (without surfactant). Further, the fermentation products did not have strong influence on phase separation. PMID:26315133

  12. Characterization of aqueous silver nitrate solutions for leakage tests

    OpenAIRE

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

    2011-01-01

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

  13. Analysis and modeling of alkali halide aqueous solutions

    DEFF Research Database (Denmark)

    Kim, Sun Hyung; Anantpinijwatna, Amata; Kang, Jeong Won;

    2016-01-01

    calculations for various electrolyte properties of alkali halide aqueous solutions such as mean ionic activity coefficients, osmotic coefficients, and salt solubilities. The model covers highly nonideal electrolyte systems such as lithium chloride, lithium bromide and lithium iodide, that is, systems that are...... very soluble in water, for example, up to more than 30 mol kg-1. Phase behaviors for the systems are analyzed at concentrations of salt up to the solubility in water at temperatures between 273 and 373 K by comparing calculated results with available experimental data and available models....

  14. Aqueous polyethylene oxide solutions

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    OpenAIRE

    K.Vijaya Bhaskar

    2012-01-01

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

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

    Science.gov (United States)

    Łuczak, Justyna; Paszkiewicz, Marta; Krukowska, Anna; Malankowska, Anna; Zaleska-Medynska, Adriana

    2016-01-01

    Ionic liquids (ILs) are widely applied to prepare metal nanoparticles and 3D semiconductor microparticles. Generally, they serve as a structuring agent or reaction medium (solvent), however it was also demonstrated that ILs can play a role of a co-solvent, metal precursor, reducing as well as surface modifying agent. The crucial role and possible types of interactions between ILs and growing particles have been presented in the Part 1 of this review paper. Part 2 of the paper gives a comprehensive overview of recent experimental studies dealing with application of ionic liquids for preparation of metal and semiconductor based nano- and microparticles. A wide spectrum of preparation routes using ionic liquids is presented, including precipitation, sol-gel technique, hydrothermal method, nanocasting and ray-mediated methods (microwave, ultrasound, UV-radiation and γ-radiation). It was found that ionic liquids formed of a 1-butyl-3-methylimidazolium [BMIM] combined with tetrafluoroborate [BF4], hexafluorophosphate [PF6], and bis(trifluoromethanesulfonyl)imide [Tf2N] are the most often used ILs in the synthesis of nano- and microparticles, due to their low melting temperature, low viscosity and good transportation properties. Nevertheless, examples of other IL classes with intrinsic nanoparticles stabilizing abilities such as phosphonium and ammonium derivatives are also presented. Experimental data revealed that structure of ILs (both anion and cation type) affects the size and shape of formed metal particles, and in some cases may even determine possibility of particles formation. The nature of the metal precursor determines its affinity to polar or nonpolar domains of ionic liquid, and therefore, the size of the nanoparticles depends on the size of these regions. Ability of ionic liquids to form varied extended interactions with particle precursor as well as other compounds presented in the reaction media (water, organic solvents etc.) provides nano- and

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

    Directory of Open Access Journals (Sweden)

    Guozhong Wu

    2013-10-01

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

  19. Mutual diffusion of sodium hyaluranate in aqueous solutions

    International Nuclear Information System (INIS)

    Highlights: • Binary diffusion coefficients for the systems containing sodium hyaluronate. • Influence of the aggregation on diffusion of the sodium hyaluronate in the aqueous media. • Estimation of the thermodynamic and mobility factors from mutual diffusion. -- Abstract: The Taylor dispersion technique has been used for measuring mutual diffusion coefficients of sodium hyaluronate in aqueous solutions at T = 298.15 K, and concentrations ranging from (0.00 to 0.50) g · dm−3. The results are interpreted on the basis of Nernst, and Onsager and Fuoss theoretical equations. From the diffusion coefficient at infinitesimal concentration, the limiting ionic conductivity and the tracer diffusion coefficient of hyaluronate ion were estimated. These studies have been complemented by molecular mechanics calculations

  20. Ternary mutual diffusion in aqueous (ethambutol dihydrochloride + hydrochloric acid) solutions

    International Nuclear Information System (INIS)

    Highlights: • Ternary diffusion coefficients for aqueous system ethambutol dihydrochloride and hydrochloric acid. • Diffusion of ethambutol dihydrochloride driven by hydrochloric acid gradients. • Coupled diffusion as indicated by cross-diffusion coefficients. - Abstract: Ternary mutual diffusion coefficients measured by the Taylor dispersion method are reported for aqueous solutions of {ethambutol dihydrochloride (1) + HCl (2)} at 25 °C and various carrier solution compositions. Mutual diffusion coefficients estimated from limiting ionic conductivities using Nernst equations are used to discuss the composition dependence of the measured diffusion coefficients. 1H NMR studies, combined with DFT calculations, confirm a fully extended conformation for the diprotonated form of the drug present under these conditions, and are consistent with an electrostatic mechanism for the strongly coupled diffusion of diprotonated ethambutol and HCl

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Science.gov (United States)

    Shirota, Hideaki; Biswas, Ranjit

    2012-11-26

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

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

    Science.gov (United States)

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

    2016-08-01

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

  4. Disordering and Melting of Aluminum Surfaces

    DEFF Research Database (Denmark)

    Stoltze, Per; Nørskov, Jens Kehlet; Landman, U.

    1988-01-01

    We report on a molecular-dynamics simulation of an Al(110) surface using the effective-medium theory to describe the interatomic interactions. The surface region is found to start melting ≅200 K below the bulk melting temperature with a gradual increase in the thickness of the disordered layer...... as the temperature approaches the bulk melting point. The more close-packed Al(111) surface shows a much weaker disordering below the melting temperature....

  5. Thermochemical study of the processes of complexation of cobalt(II) ions with L-histidine in aqueous solution

    Science.gov (United States)

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

    2015-09-01

    Thermal effects of the complexation of cobalt(II) ions with L-histidine at 298.15 K and several values of the ionic strength against the background of KNO3 are determined by means of direct calorimetry. The standard thermodynamic characteristics of the reactions of complexation in the aqueous solution have been calculated.

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

    Science.gov (United States)

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

  7. Ionic liquid-in-oil microemulsions.

    Science.gov (United States)

    Eastoe, Julian; Gold, Sarah; Rogers, Sarah E; Paul, Alison; Welton, Tom; Heenan, Richard K; Grillo, Isabelle

    2005-05-25

    Phase stability and small-angle neutron scattering (SANS) data show that surfactant-stabilized nanodomains of a typical ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate [bmim][BF4]) may be dispersed by the nonionic surfactant Triton-X100 in cyclohexane. Analyses of these SANS data are consistent with the formation of ionic liquid-in-oil microemulsion droplets. PMID:15898765

  8. Improved ionic model of liquid uranium dioxide

    NARCIS (Netherlands)

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

    2000-01-01

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

  9. Engineered microorganisms having resistance to ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Ruegg, Thomas Lawrence; Thelen, Michael P.

    2016-03-22

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

  10. Gaseous Hydrocarbon Separations Using Functionalized Ionic Liquids

    Directory of Open Access Journals (Sweden)

    Moura Leila

    2016-03-01

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

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

    Science.gov (United States)

    Agarwal, Manish; Sharma, Ruchi; Chakravarty, Charusita

    2007-10-28

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

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

    Science.gov (United States)

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

    2015-11-28

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

  13. Asymmetric Melting and Freezing Kinetics in Silicon.

    OpenAIRE

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

    1986-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Dr. R. G. Reddy

    2007-09-01

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

  15. Ionic liquid incorporating thiosalicylate for metal removal

    Science.gov (United States)

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

    2012-09-01

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

  16. Application of Ionic Liquids in Hydrometallurgy

    Directory of Open Access Journals (Sweden)

    Jesik Park

    2014-08-01

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

  17. CONTROLLING THE AQUEOUS MISCIBILITY OF IONIC LIQUIDS: A NOVEL AQUEOUS BIPHASIC SYSTEM FROM WATER-MISCIBLE IONIC LIQUID AND A WATER-STRUCTURING SALT. (R828257)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  18. Solvent effects on the polar network of ionic liquid solutions

    Science.gov (United States)

    Bernardes, Carlos E. S.; Shimizu, Karina; Canongia Lopes, José N.

    2015-05-01

    Molecular dynamics simulations were used to probe mixtures of ionic liquids (ILs) with common molecular solvents. Four types of systems were considered: (i) 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide plus benzene, hexafluorobenzene or 1,2-difluorobenzene mixtures; (ii) choline-based ILs plus ether mixtures (iii) choline-based ILs plus n-alkanol mixtures; and (iv) 1-butyl-3-methylimidazolium nitrate and 1-ethyl-3-methylimidazolium ethyl sulfate aqueous mixtures. The results produced a wealth of structural and aggregation information that highlight the resilience of the polar network of the ILs (formed by clusters of alternating ions and counter-ions) to the addition of different types of molecular solvent. The analysis of the MD data also shows that the intricate balance between different types of interaction (electrostatic, van der Waals, H-bond-like) between the different species present in the mixtures has a profound effect on the morphology of the mixtures at a mesoscopic scale. In the case of the IL aqueous solutions, the present results suggest an alternative interpretation for very recently published x-ray and neutron diffraction data on similar systems.

  19. Antinociceptive activity of Delta9-tetrahydrocannabinol non-ionic microemulsions.

    Science.gov (United States)

    Lazzari, P; Fadda, P; Marchese, G; Casu, G L; Pani, L

    2010-06-30

    Delta(9)-Tetrahydrocannabinol (Delta(9)-THC), the major psychoactive constituent of Cannabis sativa L., has been widely studied for its potential pharmaceutical application in the treatment of various diseases and disturbs. This sparingly soluble terpeno-phenolic compound is not easy to handle and to be formulated in pharmaceutical preparations. The aim of this work was to develop a stable aqueous Delta(9)-THC formulation acceptable for different ways of administration, and to evaluate the therapeutic properties of the new Delta(9)-THC based preparation for pain treatment. Due to the thermodynamic stability and advantages of microemulsion based systems, the study was focused on the identification of aqueous microemulsion based systems containing Delta(9)-THC. Oil in water Delta(9)-THC microemulsions were individuated through phase diagrams construction, using the non-ionic surfactant Solutol HS15, being this surfactant acceptable for parenteral administration in human. A selected microemulsion samples containing 0.2 wt% of Delta(9)-THC, stable up to 52 degrees C, was successfully assayed on animal models of pain. Significant antinociceptive activity has been detected by both intraperitoneal and intragastric administration of the new Delta(9)-THC pharmaceutical preparation. The effect has been highlighted in shorter time if compared to a preparation of the same active principle based on previously reported conventional preparation. PMID:20399844

  20. Multijet investigations with tin melt

    International Nuclear Information System (INIS)

    In the experiments which are described in this paper, several jets or chains of drops by hot tin melt were side by side brought into a container filled with water, so that the melt formed a plane in the water. By the ignition of an underwater bridgewire explosion an interaction was triggered at that jet, which was nearest to the explosion centre. Under suitable conditions this interaction leaped over to neighbouring jets and reached even the most distant jet, when not stopped before. The propagation could be recorded by a high speed camera. The records showed, that the interactions propagated in special directions and the velocity of the propagation was in a range of 2 to 8 m/s. The position of the drops and their distance to each other is very important for the propagation. By separating the single melt jets with fixed copper plats, it could be showed, that hydrodynamic effects are not responsible for the propagation of the interactions. Shock waves, resulting from the interaction cycles, are the cause for the propagation of the interactions. (orig.)

  1. Preparation and characterization of melt intercalated poly(ethylene oxide)/lithium montmorillonite nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Erceg, M., E-mail: merceg@ktf-split.hr [Department of Organic Technology, Faculty of Chemistry and Technology, University of Split, Teslina 10/V, 21000 Split (Croatia); Jozić, D. [Department of Inorganic Technology, Faculty of Chemistry and Technology, University of Split, Teslina 10/V, 21000 Split (Croatia); Banovac, I.; Perinović, S. [Department of Organic Technology, Faculty of Chemistry and Technology, University of Split, Teslina 10/V, 21000 Split (Croatia); Bernstorff, S. [Elettra-Sincrotrone Trieste S.C.p.A., Strada Statale 14, km 163.5 in AREA Science Park, 34149 Basovizza, Trieste (Italy)

    2014-03-01

    Highlights: • PEO/LiMMT nanocomposites were prepared by melt intercalation. • An addition of LiMMT decreases the crystallinity of PEO. • LiMMT significantly lowers the thermal stability of PEO. • LiMMT changes degradation mechanism of PEO as confirmed by kinetic analysis. • Significant conductivity increase is observed and optimum LiMMT content determined. - Abstract: The structure, crystallinity, thermal properties, kinetic analysis of thermal degradation and ionic conductivity of poly(ethylene oxide)/lithium montmorillonite (PEO/LiMMT) nanocomposites prepared by melt intercalation were investigated. An intercalated structure of PEO/LiMMT nanocomposites was found by small angle X-ray scattering (SAXS). Differential scanning calorimetry (DSC) shows that an addition of LiMMT decreases the crystallinity of PEO which completely disappears above 80 wt.% of LiMMT and decreases PEO melting temperature. The influence of LiMMT on the PEO crystallinity was also observed by SAXS and Fourier Transform Infrared Spectroscopy (FTIR). Thermogravimetric analysis (TGA) indicates that LiMMT significantly lowers the thermal stability of PEO and changes its degradation mechanism what is confirmed by kinetic analysis using isoconversional method and deconvolution procedure. Electrochemical impedance spectroscopy reveals the significant increase in ionic conductivity at room temperature with addition of LiMMT and optimum LiMMT content concerning conductivity was defined.

  2. Preparation and characterization of melt intercalated poly(ethylene oxide)/lithium montmorillonite nanocomposites

    International Nuclear Information System (INIS)

    Highlights: • PEO/LiMMT nanocomposites were prepared by melt intercalation. • An addition of LiMMT decreases the crystallinity of PEO. • LiMMT significantly lowers the thermal stability of PEO. • LiMMT changes degradation mechanism of PEO as confirmed by kinetic analysis. • Significant conductivity increase is observed and optimum LiMMT content determined. - Abstract: The structure, crystallinity, thermal properties, kinetic analysis of thermal degradation and ionic conductivity of poly(ethylene oxide)/lithium montmorillonite (PEO/LiMMT) nanocomposites prepared by melt intercalation were investigated. An intercalated structure of PEO/LiMMT nanocomposites was found by small angle X-ray scattering (SAXS). Differential scanning calorimetry (DSC) shows that an addition of LiMMT decreases the crystallinity of PEO which completely disappears above 80 wt.% of LiMMT and decreases PEO melting temperature. The influence of LiMMT on the PEO crystallinity was also observed by SAXS and Fourier Transform Infrared Spectroscopy (FTIR). Thermogravimetric analysis (TGA) indicates that LiMMT significantly lowers the thermal stability of PEO and changes its degradation mechanism what is confirmed by kinetic analysis using isoconversional method and deconvolution procedure. Electrochemical impedance spectroscopy reveals the significant increase in ionic conductivity at room temperature with addition of LiMMT and optimum LiMMT content concerning conductivity was defined

  3. Removal of ionic dyes from water by solvent extraction using reverse micelles.

    Science.gov (United States)

    Pandit, P; Basu, S

    2004-04-15

    Several methods (e.g., UV/H2O2 oxidation, adsorption, flocculation-precipitation) are normally employed to remove dye from water. A new technique based on liquid/liquid extraction using reverse micelles is proposed whereby recovery of solvent and reuse of dye is possible. Experiments were conducted by mixing a known quantity of dye in aqueous phase and solvent-containing surfactants in a simple mixer. The separation of solvent phase, containing encapsulated dye in reverse micelles, from aqueous phase due to gravity results in separation of dye from water. The removal of different ionic dyes (e.g., eosin yellow, methylene blue, malachite green, methyl orange, orange G) from aqueous phase in the presence of different cationic and anionic surfactants [e.g., sodium dodecylbenzene sulfonate, sodium bis(2-ethylhexyl) sulfosuccinate, hexadecyltrimethylammonium bromide, and cetyl pyridinium chloride] in different solvents (e.g., amyl alcohol, benzyl alcohol, methyl benzoate, and isooctane) were studied by conducting experiments. The percentage removal of dye from aqueous phase increases with the decrease in dye concentration or with the increase in surfactants concentration. Furthermore, the percentage COD removal of dye is increased with the increase in surfactant concentration. The nature of solvent has minimal effect on percentage removal of dye. The ratio of solventto aqueous phase volume required for the removal of dye decreases with the increase in surfactant concentration. It is possible to back-extract dye into aqueous phase and recover solvent by using counterionic surfactants. The separation of aqueous phase from the aqueous-phase solvent dispersion is faster for amyl alcohol as compared to benzyl alcohol and methyl benzoate. A theoretical model based on ion-exchange reaction between surfactants and dye is used to analyze the experimental data. PMID:15116851

  4. Solid Catalyst with Ionic Liquid Layer (SCILL). A concept to improve the selectivity of selective hydrogenations

    Energy Technology Data Exchange (ETDEWEB)

    Jess, A.; Korth, W. [Bayreuth Univ. (Germany). Chair of Chemical Engineering

    2011-07-01

    Catalytic hydrogenations are important for refinery processes, petrochemical applications as well as for numerous processes of the fine chemicals industry. In some cases, hydrogenations consist of a sequence of consecutive reactions, and the desired product is the intermediate. An important goal is then a high yield and selectivity to the intermediate, if possible at a high conversion degree. The selectivity to an intermediate primarily depends on the chemical nature of the catalyst, but may also be influenced by diffusion processes. Ionic liquids (ILs) are low melting salts (< 100 C) and represent a promising solvent class. This paper focuses on the concept of a Solid Catalyst with Ionic Liquid Layer (SCILL), where the solid catalyst is coated with a thin IL layer to improve the selectivity. (orig.)

  5. Density of iron-nickel melts

    International Nuclear Information System (INIS)

    Iron-nickel melt density is studied in the wide ranges of concentrations and temperatures using the penetrating gamma radiation method. Mean coordination numbers and interatomic distances have been calculated. Attainment of equilibrium state from the point of view of the melt composition and microvolume structure requires, depending on melting condition, rather long time in some cases, up to several hours. Concentration dependences of density, mean coordination numbers and interatomic distances indicate complex, heterogeneous microstructure of the Fe-Ni melts. In equilibrium the level of heterogeneity as well as the short-range order structure significantly depend on melt composition

  6. Solvation free energies in [bmim]-based ionic liquids: Anion effect toward solvation of amino acid side chain analogues

    Science.gov (United States)

    Latif, Muhammad Alif Mohammad; Micaêlo, Nuno; Abdul Rahman, Mohd Basyaruddin

    2014-11-01

    Stochastic molecular dynamics simulations were performed to investigate the solvation free energy of 15 neutral amino acid side chain analogues in aqueous and five, 1-butyl-3-methylimidazolium ([BMIM])-based ionic liquids. The results in aqueous were found highly correlated with previous experimental and simulation data. Meanwhile, [BMIM]-based RTILs showed better solvation thermodynamics than water to an extent that they were capable of solvating molecules immiscible in water. Non-polar analogues showed stronger solvation in hydrophobic RTIL anions such as [PF6]- and [Tf2N]- while polar analogues showed stronger solvation in the more hydrophilic RTIL anions such as [Cl]-, [TfO]- and [BF4]-.

  7. Infrared spectroscopy of ionic clusters

    International Nuclear Information System (INIS)

    This thesis describes new experiments wherein the infrared vibrational predissociation spectra of a number of mass-selected ionic cluster systems have been obtained and analyzed in the 2600 to 4000 cm-1 region. The species studied include: the hydrated hydronium ions, H3O+ (H2O)3-10, ammoniated ammonium ions, NH4+(NH3)1-10 and cluster ions involving both water and ammonia around an ammonium ion core, (mixed clusters) NH4+(NH3)n(H2O)m (n+m=4). In each case, the spectra reveal well resolved structures that can be assigned to transitions arising from the vibrational motions of both the ion core of the clusters and the surrounding neutral solvent molecules. 154 refs., 19 figs., 8 tabs

  8. Infrared spectroscopy of ionic clusters

    Energy Technology Data Exchange (ETDEWEB)

    Price, J.M. (California Univ., Berkeley, CA (USA). Dept. of Chemistry Lawrence Berkeley Lab., CA (USA))

    1990-11-01

    This thesis describes new experiments wherein the infrared vibrational predissociation spectra of a number of mass-selected ionic cluster systems have been obtained and analyzed in the 2600 to 4000 cm{sup {minus}1} region. The species studied include: the hydrated hydronium ions, H{sub 3}O{sup +} (H{sub 2}O){sub 3 {minus}10}, ammoniated ammonium ions, NH{sub 4}{sup +}(NH{sub 3}){sub 1 {minus}10} and cluster ions involving both water and ammonia around an ammonium ion core, (mixed clusters) NH{sub 4}{sup +}(NH{sub 3}){sub n}(H{sub 2}O){sub m} (n+m=4). In each case, the spectra reveal well resolved structures that can be assigned to transitions arising from the vibrational motions of both the ion core of the clusters and the surrounding neutral solvent molecules. 154 refs., 19 figs., 8 tabs.

  9. Actinide chemistry in ionic liquids.

    Science.gov (United States)

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

    2013-04-01

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

  10. Inclusion complex formation of ionic liquids with 4-sulfonatocalixarenes studied by competitive binding of berberine alkaloid fluorescent probe

    Science.gov (United States)

    Miskolczy, Zsombor; Biczók, László

    2009-07-01

    A clinically important natural isoquinoline alkaloid, berberine, was used as a fluorescent probe to study the encapsulation of 1-alkyl-3-methylimidazolium (C nMIm +) type ionic liquids in 4-sulfonato-substituted calix[4]arene (SCX4) and calix[6]arene (SCX6) at pH 2. Addition of ionic liquids to the aqueous solution of berberine-SCXn inclusion complexes brought about considerable fluorescence intensity diminution due to the extrusion of berberine from the macrocycle into the aqueous phase by the competitive inclusion of C nMIm + cation. The lengthening of the aliphatic side chain of the imidazolium moiety diminished the equilibrium constant of complexation with SCX4, but enhanced the stability of SCX6 complexes. Larger binding strength was found for SCX4.

  11. Electrodeposition of ruthenium, rhodium and palladium from nitric acid and ionic liquid media: Recovery and surface morphology of the deposits

    International Nuclear Information System (INIS)

    Research highlights: → Platinum group metals are man-made noble metals. → Electrochemical recovery of fission platinoids. → Recovery from nitric acid medium. → Recovery from ionic liquid medium. → Platinoids with exotic surface morphologies. - Abstract: Electrodeposition is a promising technique for the recovery of platinum group metals with unique surface morphologies. The electrodeposition of palladium, ruthenium and rhodium from aqueous nitric acid, and non-aqueous 1-butyl-3-methylimidazolium chloride ionic liquid medium was studied at stainless steel electrode. The surface morphology and elemental composition of the resultant deposit were probed by scanning electron microscopy (SEM) and energy dispersive X-ray (EDS) analysis. Deposits with diverse surface morphologies and metal compositions were obtained by varying the composition of the electrolytic medium and applied potential. The results demonstrate the possibility of tailoring the morphologies of PGMs by controlling the composition and potential needed for electrodeposition.

  12. The attenuation of oscillatory thermo-capillary convection in the oxide melt by a transverse magnetic field

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

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

  13. Industrial opportunities of controlled melt flow during glass melting, part 1: Melt flow evaluation

    Czech Academy of Sciences Publication Activity Database

    Dyrčíková, Petra; Hrbek, Lukáš; Němec, Lubomír

    2014-01-01

    Roč. 58, č. 2 (2014), s. 111-117. ISSN 0862-5468 R&D Projects: GA TA ČR TA01010844 Institutional support: RVO:67985891 Keywords : glass melting * controlled flow * space utilization Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 0.435, year: 2014 http://www.ceramics-silikaty.cz/2014/pdf/2014_02_111.pdf

  14. Melting by temperature-modulated calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Wunderlich, B.; Okazaki, Iwao; Ishikiriyama, Kazuhiko; Boller, A. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemistry]|[Oak Ridge National Lab., TN (United States)

    1997-09-01

    Well-crystallized macromolecules melt irreversibly due to the need of molecular nucleation, while small molecules melt reversibly as long as crystal nuclei are present to assist crystallization. Furthermore, imperfect crystals of low-molar-mass polymers may have a sufficiently small region of metastability between crystallization and melting to show a reversing heat-flow component due to melting of poor crystals followed by crystallization of imperfect crystals which have insufficient time to perfect before the modulation switches to heating and melts the imperfect crystals. Many metals, in turn. melt sharply and reversibly as long as nuclei remain after melting for subsequent crystallization during the cooling cycle. Their analysis is complicated, however, due to thermal conductivity limitations of the calorimeters. Polymers of sufficiently high molar mass, finally, show a small amount of reversible. local melting that may be linked to partial melting of individual molecules. Experiments by temperature-modulated calorimetry and model calculations are presented. The samples measured included poly(ethylene terephthalate)s, poly(ethylene oxide)s, and indium. Two unsolved problems that arose from this research involve the origin of a high, seemingly stable, reversible heat capacity of polymers in the melting region, and a smoothing of melting and crystallization into a close-to-elliptical Lissajous figure in a heat-flow versus sample-temperature plot.

  15. Two-phase melt systems of ibuprofen for enhanced membrane permeation.

    Science.gov (United States)

    Kang, Lisheng; Park, M O; Jun, H W

    2004-11-01

    A novel method to convert S- and racemic (RS-) ibuprofen (Ibu) into an oily state at ambient temperature (25 degrees C) was developed. Using menthol and aqueous isopropanol (IPA) as melting point depressing agents, the two-phase melt systems (TMSs) of Ibu consisting of a homogeneous oily phase and a homogeneous aqueous phase were obtained. In TMS with a high S-Ibu: menthol ratio and a low IPA content, the oily phase primarily consisted of Ibu and menthol, whereas the majority of the aqueous phase was IPA and buffer. Using this method, the S-Ibu concentration in the oily phase reached as high as 70% (w/w). The compositional phase diagram was obtained using a titration method to study the relationship between the melting states of the solid components and system composition. S- and RS-Ibu showed different phase diagrams, and the maximum concentration of S-Ibu measured in the oily phase of TMS was much greater than that of RS-Ibu. The permeation study of a series of TMS and non-TMS systems showed that S-Ibu penetrated through shed snake skin faster than RS-Ibu, and the contents of IPA and menthol significantly affected the permeation rates of ibuprofen across shed snake skin, which may be attributed to the higher lipophilicity, and thus, higher solubility of S-Ibu in the skin than RS-Ibu. Such results support the use of S-Ibu TMS for topical formulation development. PMID:15581071

  16. Long term coolability of a core melt

    International Nuclear Information System (INIS)

    One of the problems which must be solved in severe accidents is the melt concrete interaction which occurs when the core debris penetrates the lower vessel head and contacts the basement. To prevent these consequences a core catcher concept is considered to be integrated into a new PWR design based on the standard German PWR. The core catcher achieves coolability by spreading and fragmentation of the ex-vessel core melt based on the process of water inlet from the bottom through the melt. In order to identify the dominant processes of flooding the melt from the bottom experiments in laboratory scale have been carried out. To get more detailed information on the very important process of water penetration into the melt, a simulant experiment has been conducted using a transparent plastic melt with the typical viscosity behaviour of an oxidic corium melt and a temperature allowing evaporation of water. (orig.(DG)

  17. Thermophysical properties of ionic liquid {1-butyl-3-methylimidazolium bromide [bmim][Br] in alkoxyalkanols + water} mixtures at different temperatures

    International Nuclear Information System (INIS)

    Highlights: ► Densities and speeds of sound of alkoxyalkanols in [bmim][Br]. ► Synthesis of room temperature ionic liquid [bmim][Br]. ► Partial molar volumes and compressibility of transfer. ► Apparent molar expansivities and the Hepler’s constant were calculated. ► Solute–solute and solute–solvent interactions and the structural changes of the solutes. - Abstract: The interactions of alkoxyalkanols with the ionic liquid 1-butyl-3-methylimidazolium bromide [bmim][Br] as a function of temperature were investigated by combination of volumetric and acoustic methods. The density, ρ, and speed of sound, u, of ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, and triethylene glycol monomethyl ether (0.00–1.01 mol·kg−1) in aqueous 1-butyl-3-methylimidazolium bromide solutions ranging from pure water to 0.29 mass% of ionic liquid have been measured at T = (288.15, 298.15 and 308.15) K and atmospheric pressure. The apparent molar volume (Vφ) and adiabatic compressibility (Kφ,S) of alkoxyalkanols in aqueous ionic liquid solution were determined at the measured temperatures. The partial molar volume (Vφ0) and partial molar adiabatic compressibility (Kφ0) of alkoxyalkanols at infinite dilution were evaluated. Transfer volumes (ΔVφ0) and transfer adiabatic compressibility (ΔKφ0) at infinite dilution from water to aqueous ionic liquid solution were also calculated. The temperature dependence of the apparent molar volume was used to calculate apparent molar expansivity (φE0) and the Hepler’s constant values, (∂2Vφ0/∂T2). The results were explained on the basis of competing patterns of interactions of co-solvent and the solute.

  18. Bioelectrocatalysis in ionic liquids. Examining specific cation and anion effects on electrode-immobilized cytochrome c.

    Science.gov (United States)

    DiCarlo, Cory M; Compton, David L; Evans, Kervin O; Laszlo, Joseph A

    2006-05-01

    Cytochrome c immobilized on alkylthiol self-assembled monolayers exhibits a characteristic Fe(II)/Fe(III) redox signal that is lost when exposed to ionic liquids composed of a butylimidazolium cation combined with either hexafluorophosphate or bis(trifluoromethylsulfonyl)imide anion. In this study it was shown that exposure to the aqueous solubilized ionic liquid components, butyl-, hexyl-, and octyl-imidazolium cations and hexafluorophosphate, tetrafluoroborate, and bis(trifluoromethylsulfonyl)imide anions, resulted in partial electrochemical signal loss. Absorbance and fluorescence measurements showed that signal loss due to the cationic ionic liquid component followed a different mechanism than that of the anionic component. Although a portion of the signal was recoverable, irreversible signal loss also occurred in both cases. The source of the irreversible component is suggested to be the loss of protein secondary structure through complexation between the ionic liquid components and the protein surface residues. The reversible electrochemical signal loss is likely due to interfacial interactions imposed between the electrode and the cytochrome heme group. The influence of the amount of exposed surface residues was explored with a simplified model protein, microperoxidase-11. PMID:16009598

  19. NOvel Fission Product Separation Based on Room-Temperature Ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Hussey, Charles L.

    2005-11-13

    The effective extraction of Cs+ and Sr2+ into a relatively new and heretofore untested hydrophobic ionic liquid, tri-n-butylmethylammonium bis[(trifluoromethyl)sulfonyl]imide was demonstrated with calix[4]arene-bis(tert-octylbenzo-crown-6) and dicyclohexano-18-crown-6, respectively. The coordinated Cs+ and Sr2+ were subsequently removed from the ionic liquid extraction solvent by an electrochemical reduction process carried out at mercury electrodes. This process is non-destructive, permitting the ionic liquid and ionophores to be recycled. Although the process is based on mercury electrodes, this is a benefit rather than a detriment because the liquid mercury containing the Cs and Sr can be easily transported to another electrochemical cell where the Cs and Sr could be electrochemically recovered from the mercury amalgam and concentrated into a minimum volume of water or some other inexpensive solvent. This should facilitate the development of a suitable waste form for the extracted Cs+ and Sr2+. Thus, the feasibility of the proposed ionic liquid-based extraction cycle for the removal of 137Cs+ and 90Sr2+ from simulated aqueous tank waste was demonstrated.

  20. Lyotropic Phase Behavior of Polybutadiene-Poly(ethylene oxide) Diblock Copolymers in Ionic Liquids

    Energy Technology Data Exchange (ETDEWEB)

    Simone, Peter M.; Lodge, Timothy P. (UMM)

    2008-08-26

    The lyotropic phase behavior of three poly(1,2-butadiene-b-ethylene oxide) diblock copolymers (PB-PEO) with different monomer volume fractions has been studied in two different ionic liquids, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMI][TFSI]) and 1-butyl-3-methylimidazolium hexafluorophosphate ([BMI][PF{sub 6}]), across the complete concentration range. The ordered microstructures present in the solutions were characterized via small-angle X-ray scattering (SAXS). The phase diagrams for the PB-PEO/ionic liquid solutions include regions corresponding to the classical copolymer microstructures: body-centered-cubic lattices of spheres, hexagonally ordered cylinders, and lamellae. Additionally, the phase diagrams also include wide regions of coexisting microstructures and regions apparently corresponding to a disordered network microstructure. The phase behavior of the PB-PEO copolymers in both ionic liquids was comparable to their previously reported aqueous solution behavior. The temperature dependence of the phase diagrams was very modest, indicative of a highly segregated system. The level of solvent selectivity was also investigated via cryogenic transmission electron microscopy (cryo-TEM) on dilute solutions. On the basis of the morphology of the dilute solution copolymer aggregate structures in the ionic liquid solvents, and on the structural length scales of the concentrated solutions, it was concluded that for PB-PEO [BMI][PF{sub 6}] behaves as a more selective solvent than [EMI][TFSI].

  1. Solubility and first hydrolysis constants of europium at different ionic strength and 303 K

    International Nuclear Information System (INIS)

    The solubility of europium at 0.02M, 0.1M and 0.7M NaClO4 ionic strength solutions was determined by a radiometric method and pEus-pCH diagrams were obtained. Hydrolysis constants were also determined at the same ionic strengths by pH titration and the values found were log *β1 -7.68±0.11, -8.07±0.10 and -8.20±0.11. The log Ksp values were -23.5±0.2, -22.7±0.2 and -21.9±0.2 for 0.02M, 0.1M and 0.7M NaClO4 ionic strengths, respectively, at 303 K under CO2-free conditions and the extrapolated value at zero ionic strength was log Ksp0 = -24.15. The working pCH ranges for the calculation of the hydrolysis constants were selected from the pEus-pCH diagrams in the region where precipitation of europium oxide or hydroxide was less than 20%. Europium removal from aqueous solutions with zeolites was explored. (author)

  2. Self-consistent field theory of polymer-ionic molecule complexation.

    Science.gov (United States)

    Nakamura, Issei; Shi, An-Chang

    2010-05-21

    A self-consistent field theory is developed for polymers that are capable of binding small ionic molecules (adsorbates). The polymer-ionic molecule association is described by Ising-like binding variables, C(i) ((a))(kDelta)(=0 or 1), whose average determines the number of adsorbed molecules, n(BI). Polymer gelation can occur through polymer-ionic molecule complexation in our model. For polymer-polymer cross-links through the ionic molecules, three types of solutions for n(BI) are obtained, depending on the equilibrium constant of single-ion binding. Spinodal lines calculated from the mean-field free energy exhibit closed-loop regions where the homogeneous phase becomes unstable. This phase instability is driven by the excluded-volume interaction due to the single occupancy of ion-binding sites on the polymers. Moreover, sol-gel transitions are examined using a critical degree of conversion. A gel phase is induced when the concentration of adsorbates is increased. At a higher concentration of the adsorbates, however, a re-entrance from a gel phase into a sol phase arises from the correlation between unoccupied and occupied ion-binding sites. The theory is applied to a model system, poly(vinyl alcohol) and borate ion in aqueous solution with sodium chloride. Good agreement between theory and experiment is obtained. PMID:20499947

  3. Capacitance of Ti3C2Tx MXene in ionic liquid electrolyte

    Science.gov (United States)

    Lin, Zifeng; Barbara, Daffos; Taberna, Pierre-Louis; Van Aken, Katherine L.; Anasori, Babak; Gogotsi, Yury; Simon, Patrice

    2016-09-01

    Ti3C2Tx MXene, a two-dimensional (2D) early transition metal carbide, has shown an extremely high volumetric capacitance in aqueous electrolytes, but in a narrow voltage window (less than 1.23 V). The utilization of MXene materials in ionic liquid electrolytes with a large voltage window has never been addressed. Here, we report the preparation of the Ti3C2Tx MXene ionogel film by vacuum filtration for use as supercapacitor electrodes operating in 1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMI-TFSI) neat ionic liquid electrolyte. Due to the disordered structure of the Ti3C2Tx hydrogel film and a stable spacing after vacuum drying, achieved through ionic liquid electrolyte immersion of the Ti3C2Tx hydrogel film, the Ti3C2Tx surface became accessible to EMI+ and TFSI- ions. A capacitance of 70 F g-1 together with a large voltage window of 3 V was obtained at a scan rate of 20 mV s-1 in neat EMI-TFSI electrolyte. The electrochemical signature indicates a capacitive behavior even at a high scan rate (500 mV s-1) and a high power performance. This work opens up the possibilities of using MXene materials with various ionic liquid electrolytes.

  4. Suppressing the dendritic growth of zinc in an ionic liquid containing cationic and anionic zinc complexes for battery applications.

    Science.gov (United States)

    Liu, Zhen; Pulletikurthi, Giridhar; Lahiri, Abhishek; Cui, Tong; Endres, Frank

    2016-05-10

    Metallic zinc is a promising negative electrode for high energy rechargeable batteries due to its abundance, low-cost and non-toxic nature. However, the formation of dendritic zinc and low Columbic efficiency in aqueous alkaline solutions during charge/discharge processes remain a great challenge. Here we demonstrate that the dendritic growth of zinc can be effectively suppressed in an ionic liquid electrolyte containing highly concentrated cationic and anionic zinc complexes obtained by dissolving zinc oxide and zinc trifluoromethylsulfonate in a protic ionic liquid, 1-ethylimidazolium trifluoromethylsulfonate. The presence of both cationic and anionic zinc complexes alters the interfacial structure at the electrode/electrolyte interface and influences the nucleation and growth of zinc, leading to compact, homogeneous and dendrite-free zinc coatings. This study also provides insights into the development of highly concentrated metal salts in ionic liquids as electrolytes to deposit dendrite-free zinc as an anode material for energy storage applications. PMID:27080261

  5. A computer program for geochemical analysis of acid-rain and other low-ionic-strength, acidic waters

    Science.gov (United States)

    Johnsson, P.A.; Lord, D.G.

    1987-01-01

    ARCHEM, a computer program written in FORTRAN 77, is designed primarily for use in the routine geochemical interpretation of low-ionic-strength, acidic waters. On the basis of chemical analyses of the water, and either laboratory or field determinations of pH, temperature, and dissolved oxygen, the program calculates the equilibrium distribution of major inorganic aqueous species and of inorganic aluminum complexes. The concentration of the organic anion is estimated from the dissolved organic concentration. Ionic ferrous iron is calculated from the dissolved oxygen concentration. Ionic balances and comparisons of computed with measured specific conductances are performed as checks on the analytical accuracy of chemical analyses. ARCHEM may be tailored easily to fit different sampling protocols, and may be run on multiple sample analyses. (Author 's abstract)

  6. Microstructure and corrosion properties of diode laser melted friction stir weld of aluminum alloy 2024 T351

    Energy Technology Data Exchange (ETDEWEB)

    Kalita, Samar Jyoti, E-mail: Samar.Kalita@und.nodak.edu [Engineered Surfaces Center, School of Engineering and Mines, University of North Dakota, Grand Forks, ND (United States)

    2011-02-15

    Friction stir welding is a promising solid state joining process for high strength aluminum alloys. Though friction stir welding eliminates the problems of fusion welding as it is performed below melting temperature (T{sub m}), it creates severe plastic deformation. Friction stir welds of some aluminum alloys exhibit relatively poor corrosion resistance. This research enhanced the corrosion properties of such welds through diode laser surface melting. A friction stir weld of aluminum alloy 2024 T351 was laser melted using a 1 kW diode laser. The melt-depth and microstructure were investigated using optical and scanning electron microscopy. The melt zone exhibited epitaxially grown columnar grains. At the interface between the melted and the un-melted zone, a thick planar boundary was observed. Energy dispersive spectroscopy analyzed the redistribution of elemental composition. The corrosion properties of the laser melted and native welds were studied in aqueous 0.5 M sodium chloride solution using open circuit potential and cyclic potentiodynamic polarization. The results show noticeable increase in the pit nucleation resistance (390 mV) after the laser surface treatment. The repassivation potential was nobler to the corrosion potential after the laser treatment, which confirmed that the resistance to pit growth was improved.

  7. Microstructure and corrosion properties of diode laser melted friction stir weld of aluminum alloy 2024 T351

    International Nuclear Information System (INIS)

    Friction stir welding is a promising solid state joining process for high strength aluminum alloys. Though friction stir welding eliminates the problems of fusion welding as it is performed below melting temperature (Tm), it creates severe plastic deformation. Friction stir welds of some aluminum alloys exhibit relatively poor corrosion resistance. This research enhanced the corrosion properties of such welds through diode laser surface melting. A friction stir weld of aluminum alloy 2024 T351 was laser melted using a 1 kW diode laser. The melt-depth and microstructure were investigated using optical and scanning electron microscopy. The melt zone exhibited epitaxially grown columnar grains. At the interface between the melted and the un-melted zone, a thick planar boundary was observed. Energy dispersive spectroscopy analyzed the redistribution of elemental composition. The corrosion properties of the laser melted and native welds were studied in aqueous 0.5 M sodium chloride solution using open circuit potential and cyclic potentiodynamic polarization. The results show noticeable increase in the pit nucleation resistance (390 mV) after the laser surface treatment. The repassivation potential was nobler to the corrosion potential after the laser treatment, which confirmed that the resistance to pit growth was improved.

  8. Solvent extraction of uranium(VI) by a dipicolinamide using a room-temperature ionic liquid

    International Nuclear Information System (INIS)

    Room-temperature ionic liquids (RTILs) have recently received increasing attention as solvent alternatives for possible application in spent fuel reprocessing, particularly in the extraction of metal ions from high-level radioactive aqueous waste, due to their unique physical and chemical properties. Herein, the solvent extraction of the uranyl ions (UO22+) was performed using N,N'-diethyl-N,N'-di(para)tolyl-dipicolinamide (Et(p)TDPA) as the extractant in a commonly used ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([C4mim][PF6]). The effects of vortexing time, phase ratio and the concentration dependence of Et(p)TDPA, nitric acid and sodium nitrate on the extraction were studied in detail. The extraction mechanism was deduced based on the slope analysis and UV-vis measurement. The distribution ratio of U from 3 mol/L nitric acid by 0.3 mol/L EtTDPA/C4mimPF6 is found to be almost 100. Conventional log-log plot analysis of the extraction equilibrium data suggests that the ions are extracted as a complex in 2:3 ratio of UO22+ to extractant, and the extraction most likely occurs by a cation-exchange mode since the concentration of C4mim+ in the aqueous phase increases linearly with the percent extraction of UO22+ evidenced by UV-vis measurement. This work promises to provide new efficient media based on RTILs for separation of uranium from the radioactive aqueous waste. (orig.)

  9. Excess molar volumes of binary mixtures (an ionic liquid + water): A review

    International Nuclear Information System (INIS)

    Highlights: • Review of excess molar volumes for mixtures of (ionic liquids (ILs) + H2O). • 6 cation groups reviewed including imidazolium and pyrrolidinium groups. • 13 anions reviewed including tetraborate, triflate, and hydrogensulphate. • Effects of anion, cation, and temperature investigated. - Abstract: This review covers recent developments in the area of excess molar volumes for mixtures of {ILs (1) + H2O (2)} where ILs refers to ionic liquids involving cations: imidazolium, pyridinium, pyrrolidinium, piperidinium, morpholinium and ammonium groups; and anions: tetraborate, triflate, hydrogensulphate, methylsulphate, ethylsulphate, thiocyanate, dicyanamide, octanate, acetate, nitrate, chloride, bromide, and iodine. The excess molar volumes of aqueous ILs were found to cover a wide range of values for the different ILs (ranging from −1.7 cm3 · mol−1 to 1.2 cm3 · mol−1). The excess molar volumes increased with increasing temperature for all systems studied in this review. The magnitude and in some cases the sign of the excess molar volumes for all the aqueous ILs mixtures, apart from the ammonium ILs, were very dependent on temperature. This was particularly important in the dilute IL concentration region. It was found that the sign and magnitude of the excess molar volumes of aqueous ILs (for ILs with hydrophobic cations), was more dependent on the nature of the anion than on the cation

  10. Cathodic treatment of the Si-SiO2 system in salt melts

    International Nuclear Information System (INIS)

    This paper studies metal ion transport in SiO2 dielectric layers during their cathodic treatment in salt melts. The preparation of the samples is described. It is shown that an important special feature of cathodic treatments of the silicon-thermal oxide system in salt melts is the formation of a new solid phase at the bottom of the micropores which leads to blocking of the current during subsequent anodic polarization. This is a difference relative to aqueous electrolyes, where cathodic treatment involving hydrogen evolution promotes corrosion of the micropores. The C-V characteristics of the electrolyte-dielectric-semiconductor systems that had been subjected to cathodic treatment in melts are examined at room temperature in 0.0 N KC1. The results are shown

  11. Influence of purity of NdF3 single crystals on their ionic conductivity

    Science.gov (United States)

    Sorokin, N. I.; Zhmurova, Z. I.; Krivandina, E. A.; Sobolev, B. P.

    2012-05-01

    Single crystals of the NdF3 superionic conductor have been grown by the Bridgman method from a melt in a helium atmosphere using a fluorinating PbF2 agent. Commercial NdF3 reagents of special purity grade, reagent grade, and pure grade are used. It is found that the ionic conductivity σ of the crystals depends considerably on the purity grade of the starting substances: at 200°C σ = 1.4 × 10-, 3 × 10-4, and 8 × 10-4 S/cm for reagents of special purity grade, reagent grade, and pure grade, respectively.

  12. Task-Specific Ionic Liquids for Mars Exploration (Green Chemistry for a Red Planet)

    Science.gov (United States)

    Karr, L. J.; Curreri, P. A.; Paley, M. S.; Kaukler, W. F.; Marone, M. J.

    2012-01-01

    Ionic Liquids (ILs) are organic salts with low melting points that are liquid at or near room temperature. The combinations of available ions and task-specific molecular designability make them suitable for a huge variety of tasks. Because of their low flammability, low vapor pressure, and stability in harsh environments (extreme temperatures, hard vacuum) they are generally much safer and "greener" than conventional chemicals and are thus suitable for a wide range of applications that support NASA exploration goals. This presentation describes several of the ongoing applications that are being developed at MSFC.

  13. Removal of copper ions from aqueous solutions by kaolinite and batch design

    International Nuclear Information System (INIS)

    The removal of copper ions from aqueous solutions by kaolinite was investigated by using a batch-type method. Effects of factors such as pH, ionic strength, temperature, acid-activation and calcination on copper adsorption were investigated. The uptake of copper was determined from changes in concentration as measured by atomic absorption spectrometry. The extent of copper adsorption increased with increasing pH and temperature and with decreasing ionic strength, acid-activation and calcination temperature. The Langmuir and Freundlich adsorption models were used to determine the isotherm parameters associated with the adsorption process. The results provide support for the adsorption of copper ions onto kaolinite. Thermodynamic parameters indicated the endothermic nature of copper adsorption on kaolinite. The experimental results were applied a batch design. As a result, the kaolinite may be used for removal of copper ions from aqueous solutions

  14. Crowding and Anomalous Capacitance at an Electrode–Ionic Liquid Interface Observed Using Operando X-ray Scattering

    OpenAIRE

    Chu, Miaoqi; Miller, Mitchell; Dutta, Pulak

    2016-01-01

    Room temperature ionic liquids are widely recognized as novel electrolytes with properties very different from those of aqueous solutions, and thus with many potential applications, but observing how they actually behave at electrolytic interfaces has proved to be challenging. We have studied the voltage-dependent structure of [TDTHP]+[NTF2]− near its interface with an electrode, using in situ synchrotron X-ray reflectivity. An anion-rich layer develops at the interface above a threshold volt...

  15. Olefins hydro-formylation catalysed by rhodium complexes using ionic liquids; Hydroformylation des olefines par les complexes du rhodium dans les liquides ioniques

    Energy Technology Data Exchange (ETDEWEB)

    Favre, F.

    2000-10-26

    Biphasic long chain olefins hydro-formylation catalysed by rhodium complexes using ionic liquids allows a selective reaction and an easy separation of the products from the catalyst. This study reports the synthesis of ionic liquids that were used as the catalyst's solvent. Their physical and chemical properties (melting point, solubility of organic substrates) can be varied with the structure of the organic cation (imidazolium, pyridinium, pyrrolydinium) and with its substituents (nature, length, number). It depends also on the nature of the inorganic anion (hexa-fluoro-phosphate, tetrafluoroborate, tri-fluoro-acetate, triflate, bistriflylamidure...). The use of phosphorus ligands bearing ionic functions proved to be efficient to maintain the onerous rhodium catalyst in the ionic liquid phase. Phosphines, phosphites and phosphinites including anionic (sulfonate, carboxylate) or cationic (imidazolium, pyridinium, guanidinium, phosphonium) groups have been synthesised. Finally, the influences of the ligand and of the ionic liquid on the catalytic system performances are described. Selectivities in aldehydes and reaction rates proved to be highly dependent on the nature of the ligand and of the ionic liquid. The different possibilities of recycling the ionic phase containing the rhodium catalyst have been also studied. (author)

  16. Melt decontamination of aluminum waste by electric arc melting

    International Nuclear Information System (INIS)

    In Korea, the decontamination and decommissioning of the retired TRIGA MARK II and III research reactors and a uranium conversion plant at the Korea Atomic Energy Research Institute (KAERI) has been under way. Hundreds of tons of metallic wastes are expected from the D and D of these facilities Therefore, prompt countermeasures should be taken to deal with the amount of wastes generated by dismantling the retired nuclear facilities. Most of the dismantled material is slightly contaminated. A recycle or volume reduction of the metallic wastes can be considered as one of the waste management options under the circumstances of the absence of a waste disposal site in Korea and the capacity limitation of the temporary waste storage facility at KAERI. The results of the XRD analysis showed that the surrogate nuclides move into the slag, which can be easily separated from the melt, and then they combine with the aluminum oxide to form a more stable compound. The distribution ratio of cobalt in the ingot was more than 40% according to the types of fluxes. A removal efficiency of more than 98% for the cesium and strontium from the ingot could be achieved due to their transportation from the ingot to the slag and the dust phase. Therefore, it can be expected that a greater part of the aluminum wastes generated from the retired research reactors can be recycled or their volumes reduced for a disposal by a melting

  17. Melt decontamination of aluminum waste by electric arc melting

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Wang Kyu; Song, Pyung Seob; Jung, Chong Hun; Oh, Won Zin [Korea Atomic Energy Research Institute, Taejeon (Korea, Republic of); Min, Byung Youn [Chungnam National University, Taejeon (Korea, Republic of)

    2005-11-15

    In Korea, the decontamination and decommissioning of the retired TRIGA MARK II and III research reactors and a uranium conversion plant at the Korea Atomic Energy Research Institute (KAERI) has been under way. Hundreds of tons of metallic wastes are expected from the D and D of these facilities Therefore, prompt countermeasures should be taken to deal with the amount of wastes generated by dismantling the retired nuclear facilities. Most of the dismantled material is slightly contaminated. A recycle or volume reduction of the metallic wastes can be considered as one of the waste management options under the circumstances of the absence of a waste disposal site in Korea and the capacity limitation of the temporary waste storage facility at KAERI. The results of the XRD analysis showed that the surrogate nuclides move into the slag, which can be easily separated from the melt, and then they combine with the aluminum oxide to form a more stable compound. The distribution ratio of cobalt in the ingot was more than 40% according to the types of fluxes. A removal efficiency of more than 98% for the cesium and strontium from the ingot could be achieved due to their transportation from the ingot to the slag and the dust phase. Therefore, it can be expected that a greater part of the aluminum wastes generated from the retired research reactors can be recycled or their volumes reduced for a disposal by a melting.

  18. Effects of ionic strength and ion pairing on (plant-wide) modelling of anaerobic digestion

    DEFF Research Database (Denmark)

    Solon, Kimberly; Flores Alsina, Xavier; Mbamba, Christian Kazadi;

    2015-01-01

    ) and ion pairing on modelling of anaerobic digestion processes in such plant-wide models of wastewater treatment. Using the BSM2 as a case study with a number of model variants and cationic load scenarios, this paper presents the effects of an improved physico-chemical description on model predictions...... and overall plant performance indicators, namely effluent quality index (EQI) and operational cost index (OCI). The acid-base equilibria implemented in the Anaerobic Digestion Model No. 1 (ADM1) are modified to account for non-ideal aqueous-phase chemistry. The model corrects for ionic strength via the Davies....... The paper describes: 1) how the anaerobic digester performance is affected by physico-chemical corrections; 2) the effect on pH and the anaerobic digestion products (CO2, CH4 and H2); and, 3) how these variations are propagated from the sludge treatment to the water line. Results at high ionic strength...

  19. Ionic conduction in alkali metal doped ZnFe/sub 2/O/sub 4/ compound

    International Nuclear Information System (INIS)

    Zinc ferric oxide (ZnFe/sub 2/O/sub 4/) has been synthesized by liquid phase chemical reaction from aqueous mixture of zinc chloride and ferric chloride in sodium hydroxide (4N) solution and effect of alkali metal on electrical characteristics was explored. The well characterized powder was pressed into pellets and dried at 80 degree C. Samples with alkali metal concentrations 10-100 ppm have been investigated to I-V measurements. The conductivity of pure compound (10-/sub 2/omega-cm)/sup-1/) lies in the semiconductor range but due to alkali metal doping the compound shows ionic conduction at room temperature. The ionic conduction is found to be increased as the dopant concentration increases.(author)

  20. Ionic liquid lubrication at electrified interfaces

    Science.gov (United States)

    Kong, Lingling; Huang, Wei; Wang, Xiaolei

    2016-06-01

    The lubrication performances of ionic liquids at electrified interfaces have been investigated by using a reciprocating sliding tribometer. Experimental results indicated that the lubricity of the confined ionic liquids was markedly affected by the application of external electric field and strong interface electric field strength could result in high friction. The influence was more pronounced for the ionic liquid with a shorter alkyl side chain in particular. The main reason of the friction increment might be ascribed to the electrically influenced surface adsorption where the charged ions were structured to form robust and ordered layers.

  1. Quantized friction across ionic liquid thin films.

    Science.gov (United States)

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

    2013-10-01

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

  2. Compatibilization of HDPE/agar biocomposites with eutectic-based ionic liquid containing surfactant

    CERN Document Server

    Shamsuri, AA; Zainudin, ES; Tahir, PM

    2014-01-01

    In this research, eutectic-based ionic liquid specifically choline chloride/glycerol was prepared at a 1:2 mole ratio. The choline chloride/glycerol was added with the different content of surfactant (hexadecyltrimethylammonium bromide). The choline chloride/glycerol-hexadecyltrimethylammonium bromide was introduced into high-density polyethylene/agar biocomposites through melt mixing. The mechanical testing results indicated that the impact strength and tensile extension of the biocomposites increased with the introduction of the choline chloride/glycerol-hexadecyltrimethylammonium bromide. The scanning electron microscope, differential scanning calorimetry and thermal gravimetric analysis results exhibited that significant decrease in the number of agar fillers pull-out, melting point and thermal decomposition temperatures of the biocomposites are also due to the choline chloride/glycerol-hexadecyltrimethylammonium bromide. The Fourier transform infrared spectra and X-ray diffractometer patterns of the bioc...

  3. Copolymer Melts in Disordered Media

    OpenAIRE

    Stepanow, S.; Dobrynin, A.; Vilgis, T.; Binder, K.

    1996-01-01

    We have considered a symmetric AB block copolymer melt in a gel matrix with preferential adsorption of A monomers on the gel. Near the point of the microphase separation transition such a system can be described by the random field Landau-Brazovskii model, where randomness is built into the system during the polymerization of the gel matrix. By using the technique of the 2-nd Legendre transform, the phase diagram of the system is calculated. We found that preferential adsorption of the copoly...

  4. ISOLATION OF URANIUM(VI) AND THORIUM(IV) FROM AQUEOUS SOLUTIONS BY INORGANIC SORBENTS

    OpenAIRE

    Menchuk, V. V.; Perlova, N. A.

    2016-01-01

    Efficiency of use of a new sorbent on the basis of a silica gel at uranium and thorium isolation from their diluted aqueous solutions was investigated. It is shown that the investigated sorbent sorbs uranium and thorium better than a known sorbent (the silica gel). Influence of phases contact time, pH, the metal nature and solution ionic composition on the efficiency of uranium and thorium sorption process was studied. Experimentally received isotherms sorption are described by means of Langm...

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

    Directory of Open Access Journals (Sweden)

    Eero eSalminen

    2014-02-01

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

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

    Science.gov (United States)

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

    2014-02-01

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

  7. Electron beam melting of sponge titanium

    International Nuclear Information System (INIS)

    Fundamental investigations were done on electron beam (EB) melting of sponge titanium by using 80 kW EB melting furnace. Results obtained are as follows: (1) To increase the melting yield of titanium in EB melting of sponge titanium, it is important to recover splashed metal by installation of water-cooled copper wall around the hearth and to decrease evaporation loss of titanium by keeping the surface temperature of molten metal just above the melting temperature of titanium without local heating. (2) Specific power consumption of drip melting of pressed sponge titanium bar and hearth melting of sponge titanium are approximately 0.9 kWh/kg-Ti and 0.5-0.7 kWh/kg-Ti, respectively. (3) Ratios of the heat conducted to water-cooled mould in the drip melting and to water-cooled hearth in the hearth melting to the electron beam input power are 50-65% and 60-65%, respectively. (4) Surface defects of EB-melted ingots include rap which occurs when the EB output is excessively great, and transverse cracks when the EB output is excessively small. To prevent surface defects, the up-down withdrawal method is effective. (author)

  8. Electrochemical preparation of photoelectrochemically active CuI thin films from room temperature ionic liquid

    International Nuclear Information System (INIS)

    Highlights: ► CuI film can be formed by anodization of Cu in ionic liquid containing iodide. ► Coordinating strength of anion in ionic liquid determine the formation of CuI. ► Photocurrent of the CuI film can be observed in aqueous solution and in ionic liquid. ► Cu layer coated on conductive substrates can be converted to CuI. - Abstract: Cuprous iodide (CuI) thin films with photoelectrochemical activity were prepared by anodizing copper wire or copper-electrodeposited tungsten wire in the room temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMI-PF6 RTIL) containing N-butyl-N-methylpyrrolidinium iodide (BMP-I). A copper coating was formed on the tungsten wire by potentiostatic electrodeposition in BMP-dicyanamide (BMP-DCA) RTIL containing copper chloride (CuCl). The CuI films formed using this method were compact, fine-grained and exhibited good adhesion. The characteristic diffraction signals of CuI were observed by powder X-ray diffractometry (XRD). X-ray photoelectron spectroscopy (XPS) also confirmed the formation of a CuI compound semiconductor. The CuI films demonstrated an apparent and stable photocurrent under white light illumination in aqueous solutions and in a RTIL. This method has enabled the electrochemical formation of CuI from a RTIL for the first time, and the first observation of a photocurrent produced from CuI in a RTIL. The coordinating strength of the anions of the RTIL is the key to the successful formation of the CuI thin film. If the coordinating strength of the anions of the RTIL is too strong, no CuI formation is observed.

  9. On the pH of Aqueous Attoliter-Volume Droplets

    Science.gov (United States)

    Ramos, Kieran P.; Velpula, Samson S.; Demille, Trevor B.; Pajela, Ryan; Goldner, Lori S.

    Droplets of water dispersed in perfluorinated liquids have widespread use including microfluidics, drug delivery and single-molecule measurements. Perfluorinated liquids are distinctly biocompatible due to their stability, low surface tension, lipophobicity, and hydrophobicity. For this reason, the effect of the perfluorinated surface on droplet contents is usually ignored. However, as the droplet diameter is reduced, we expect that any effect of the water/oil interface on droplet contents will become more obvious. We studied the pH of attoliter-volume aqueous droplets in perfluorinated liquids using pH-sensing fluorescent dyes. Droplets were prepared either by sonication or extrusion from buffer and perfluorinated liquids (FC40 or FC77). A non-ionic surfactant was used to stabilize the droplets. Buffer strength, ionic strength, and pH of the aqueous phase were varied and resulting droplet pH compared to the pH of the buffer from which they were formed. Preliminary data are consistent with a pH in droplets that depends on the concentration of non-ionic surfactant. At low surfactant concentrations, the pH in droplets is distinctly lower than the stock buffer. However, as the concentration of non-ionic surfactant is increased the change in pH decreases. This work was funded by NSF/DBI-1152386.

  10. Comparison between an ionic (Ioglicinate) and a non-ionic (Iohexol) contrast medium in renal CT

    International Nuclear Information System (INIS)

    A simple blind study (90 patients) was performed to compare a non-ionic contrast medium (Iohexol) at two concentration levels with an ionic contrast medium (Ioglicinate) in renal CT. In the excretory phase relevant to routine examination, the non-ionic contrast medium showed a significantly poorer imaging quality despite identical iodine content. This was due to interface artefacts at the pelvi-calyceal system caused by an elevated contrast urine concentration at reduced osmotic diuresis. (orig.)

  11. Comparison between an ionic (Ioglicinate) and a non-ionic (Iohexol) contrast medium in renal CT

    Energy Technology Data Exchange (ETDEWEB)

    Weigert, F.; Hartmann, A.; Rohde, U.

    1986-05-01

    A simple blind study (90 patients) was performed to compare a non-ionic contrast medium (Iohexol) at two concentration levels with an ionic contrast medium (Ioglicinate) in renal CT. In the excretory phase relevant to routine examination, the non-ionic contrast medium showed a significantly poorer imaging quality despite identical iodine content. This was due to interface artefacts at the pelvi-calyceal system caused by an elevated contrast urine concentration at reduced osmotic diuresis.

  12. Chemical and heating treatments of ionic monolayer-protected clusters (IMPCs) with different surface counter anions.

    Science.gov (United States)

    Choo, Hosun; Isaacs, Steven R; Small, Adam; Parmley, Seth; Shon, Young-Seok

    2007-12-01

    This paper shows an in-depth study on the chemical and thermal responses of two ionic monolayer-protected gold clusters (Oct(4)N(+-)Br- and Oct(4)N(+-)O(3)SS-IMPCs). Two IMPCs displayed completely different phase-transfer behaviors when the solutions were in contact with the aqueous solution containing N-(2-mercaptopropionyl)glycine (tiopronin). Not Oct(4)N(+-)O(3)SS-IMPCs but Oct(4)N(+-)Br-IMPCs experienced a facile phase transfer from the organic layer to the aqueous layer, which was resulted from the displacement of ionic ligands by tiopronin monolayers on the gold nanoparticle surface. When the toluene solution containing Oct(4)N(+-)Br-IMPCs was treated with the aqueous solution containing NaCl salts, the UV-vis spectrum of the solution containing Oct(4)N(+-)Br-IMPCs undertook a fast spectral evolution caused by decomposition/agglomeration of IMPCs. In contrast, Oct(4)N(+-)O(3)SS-IMPCs exhibited much higher stability against the NaCl treatments. The Oct(4)N(+-)O(3)SS-IMPCs also displayed a superior thermal stability at relatively high temperature of approximately 110 degrees C. Core size evolutions of Oct(4)N(+-)O(3)SS-IMPCs without a fast decomposition or aggregation of clusters were also observed during solid-state heating treatments at approximately 150 and approximately 200 degrees C. These results support that the presence of different anions clearly affect the overall stability of ionic nanoparticles. The stronger binding property of thiosulfate anions compared to bromide anions with gold nanoparticle surfaces makes Oct(4)N(+-)O(3)SS-IMPCs chemically more inert and thermally more stable. PMID:17719060

  13. A spectroscopic and computational study of Al(III) complexes in cryolite melts: Effect of cation nature

    International Nuclear Information System (INIS)

    Highlights: ► We investigate Li, Na and K cryolite melts by Raman spectroscopy and dft. ► A slight red shift of main Raman peaks is observed in the row Li+, Na+, K+. ► A decrease of the half-widths of peaks is observed in the same row. ► Fluoroaluminates and their complexation kinetics play an important role. - Abstract: Lithium, sodium and potassium cryolite melts are probed by Raman spectroscopy in a wide range of the melt composition. The experimental data demonstrate a slight red shift of main peaks and a decrease of their half-widths in the row Li+, Na+, K+. Quantum chemical modelling of the systems is performed at the density functional theory level. The ionic environment is found to play a crucial role in the energy of fluoroaluminates. Potential energy surfaces describing the formation/dissociation of certain complex species, as well as model Raman spectra are constructed and compared with those obtained recently for sodium containing cryolite melts (R.R. Nazmutdinov, et al., Spectrochim, Acta A 75 (2010) 1244.). The calculations show that the cation nature affects the geometry of the ionic associates as well as the equilibrium and kinetics of the complexation processes. This enables to interpret both original experimental data and those reported in literature

  14. A spectroscopic and computational study of Al(III) complexes in cryolite melts: Effect of cation nature

    Energy Technology Data Exchange (ETDEWEB)

    Nazmutdinov, Renat R., E-mail: nazmutdi@mail.ru [Kazan National Research Technological University, K. Marx Str., 68, 420015 Kazan, Republic of Tatarstan (Russian Federation); Zinkicheva, Tamara T. [Kazan National Research Technological University, K. Marx Str., 68, 420015 Kazan, Republic of Tatarstan (Russian Federation); Vassiliev, Sergey Yu. [M.V. Lomonosov Moscow State University, Chemical Faculty, Leninskie Gory, 119991 Moscow (Russian Federation); Glukhov, Dmitrii V. [Kazan National Research Technological University, K. Marx Str., 68, 420015 Kazan, Republic of Tatarstan (Russian Federation); Tsirlina, Galina A. [M.V. Lomonosov Moscow State University, Chemical Faculty, Leninskie Gory, 119991 Moscow (Russian Federation); Probst, Michael [Institute of Ions Physics and Applied Physics, University of Innsbruck, A-6020 Innsbruck (Austria)

    2013-02-01

    Highlights: ► We investigate Li, Na and K cryolite melts by Raman spectroscopy and dft. ► A slight red shift of main Raman peaks is observed in the row Li{sup +}, Na{sup +}, K{sup +}. ► A decrease of the half-widths of peaks is observed in the same row. ► Fluoroaluminates and their complexation kinetics play an important role. - Abstract: Lithium, sodium and potassium cryolite melts are probed by Raman spectroscopy in a wide range of the melt composition. The experimental data demonstrate a slight red shift of main peaks and a decrease of their half-widths in the row Li{sup +}, Na{sup +}, K{sup +}. Quantum chemical modelling of the systems is performed at the density functional theory level. The ionic environment is found to play a crucial role in the energy of fluoroaluminates. Potential energy surfaces describing the formation/dissociation of certain complex species, as well as model Raman spectra are constructed and compared with those obtained recently for sodium containing cryolite melts (R.R. Nazmutdinov, et al., Spectrochim, Acta A 75 (2010) 1244.). The calculations show that the cation nature affects the geometry of the ionic associates as well as the equilibrium and kinetics of the complexation processes. This enables to interpret both original experimental data and those reported in literature.

  15. Probing depth dependencies of melt emplacement on time dependent quantities in a continental rift scenario with melting and melt extraction

    Science.gov (United States)

    Wallner, Herbert; Schmeling, Harro

    2014-05-01

    Since some years seismological observations provide increasing evidence of a discontinuity near the mid of older mantle lithosphere. Explanation may be a melt infiltration front (MIF) as upper margin of an evolving network of veins. These are formed by crystallized melt supplied by episodic melting events in the asthenosphere. To test this concept geodynamically we performed numerical modelling applying melting, extraction of melt and emplacement in a viscous matrix. Thereupon, we were faced to the problem defining an intrusion level for the melt. Findings of prior studies led to the need of movable, process dependent boundaries of the emplacement zone additionally making the process probably more self-consistent. Here we present a preliminary study exploring several empirical attempts to relate time dependent states to an upward moving boundary for intrusion. Modeled physics is based on thermo-mechanics of visco-plastic flow. The equations of conservation of mass, momentum and energy are solved for a multi component (crust-mantle) and two phase (melt-matrix) system. Rheology is temperature-, pressure-, and stress-dependent. In consideration of depletion and enrichment melting and solidification are controlled by a simplified linear binary solid solution model. The Compaction Boussinesq Approximation and the high Prandtl number approximation are used, elasticity is neglected and geometry is restricted to 2D. Approximation is done with the Finite Difference Method with markers in an Eulerian formulation (FDCON). Model guiding scenario is a extending thick lithosphere associated to by updoming asthenosphere probably additionally heated by a plume nearby. As the P-T conditions in the asthenosphere are near the solidus caused changes may increase melting and generate partial melt. Against conventional expectations on permeability at lithosphere-asthenosphere boundary (LAB) depth a fast melt transport into and sometimes through the lithosphere often is observed. The

  16. Dynamical meson melting in holography

    International Nuclear Information System (INIS)

    We discuss mesons in thermalizing gluon backgrounds in the N=2 supersymmetric QCD using the gravity dual. We numerically compute the dynamics of a probe D7-brane in the Vaidya-AdS geometry that corresponds to a D3-brane background thermalizing from zero to finite temperatures by energy injection. In static backgrounds, it has been known that there are two kinds of brane embeddings where the brane intersects the black hole or not. They correspond to the phases with melted or stable mesons. In our dynamical setup, we obtain three cases depending on final temperatures and injection time scales. The brane stays outside of the black hole horizon when the final temperature is low, while it intersects the horizon and settles down to the static equilibrium state when the final temperature is high. Between these two cases, we find the overeager case where the brane dynamically intersects the horizon although the final temperature is not high enough for a static brane to intersect the horizon. The interpretation of this phenomenon in the dual field theory is meson melting due to non-thermal effects caused by rapid energy injection. In addition, we comment on the late time evolution of the brane and a possibility of its reconnection

  17. Monitoring of polymer melt processing

    International Nuclear Information System (INIS)

    The paper reviews the state-of-the-art of in-line and on-line monitoring during polymer melt processing by compounding, extrusion and injection moulding. Different spectroscopic and scattering techniques as well as conductivity and viscosity measurements are reviewed and compared concerning their potential for different process applications. In addition to information on chemical composition and state of the process, the in situ detection of morphology, which is of specific interest for multiphase polymer systems such as polymer composites and polymer blends, is described in detail. For these systems, the product properties strongly depend on the phase or filler morphology created during processing. Examples for optical (UV/vis, NIR) and ultrasonic attenuation spectra recorded during extrusion are given, which were found to be sensitive to the chemical composition as well as to size and degree of dispersion of micro or nanofillers in the polymer matrix. By small-angle light scattering experiments, process-induced structures were detected in blends of incompatible polymers during compounding. Using conductivity measurements during extrusion, the influence of processing conditions on the electrical conductivity of polymer melts with conductive fillers (carbon black or carbon nanotubes) was monitored. (topical review)

  18. Melting a Sample within TEMPUS

    Science.gov (United States)

    2003-01-01

    One of the final runs of the TEMPUS experiment shows heating of a sample on STS-94, July 15, 1997, MET:14/11:01 (approximate) and the flows on the surface. At the point this image was taken, the sample was in the process of melting. The surface of the sample is begirning to flow, looking like the motion of plate tectonics on the surface of a planet. During this mission, TEMPUS was able to run than 120 melting cycles with zirconium, with a maximum temperature of 2,000 degrees C, and was able to undercool by 340 degrees -- the highest temperature and largest undercooling ever achieved in space. The TEMPUS investigators also have provided the first measurements of viscosity of palladium-silicon alloys in the undercooled liquid alloy which are not possible on Earth. TEMPUS (stands for Tiegelfreies Elektromagnetisches Prozessiere unter Schwerelosigkeit (containerless electromagnetic processing under weightlessness). It was developed by the German Space Agency (DARA) for flight aboard Spacelab. The DARA project scientist was Igon Egry. The experiment was part of the space research investigations conducted during the Microgravity Science Laboratory-1R mission (STS-94, July 1-17 1997). DARA and NASA are exploring the possibility of flying an advanced version of TEMPUS on the International Space Station.(176KB JPEG, 1350 x 1516 pixels; downlinked video, higher quality not available) The MPG from which this composite was made is available at http://mix.msfc.nasa.gov/ABSTRACTS/MSFC-0300193.html.

  19. Stability of Ionic Colloidal Crystals (ICCs)

    Science.gov (United States)

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

    2003-03-01

    Ionic colloidal crystals (ICCs) are here defined as ordered multicomponent colloids formed by attractive electrostatic interactions. Compared to previous approaches to colloidal crystallization, the ICC approach holds the potential for self-assembly of a wide range of structures not easily accessible by other methods. In this work, the colloid-chemical conditions under which ICCs are stable have been theoretically analyzed. A model is presented in which two dimensionless parameters are found to fully characterize an ICC system. We calculate the Madelung constant for ICCs of several classical ionic crystal structures as a function of these two parameters, and discuss the parallels between the ICC Madelung constants and the classical ionic case. Experimentally accessible regions of surface charge, particle sizes, salt concentration, and temperature where ionic colloidal crystallization should be possible are identified.

  20. Ionic Liquid Epoxy Composite Cryotanks Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this work is to determine the optimal process for manufacturing lightweight linerless cryogenic storage tanks using ionic liquid epoxy composite...