Imidazolium based ionic liquids. 1-Ethanol-3-methyl-imidazolium dicyanoamide: Thermochemical measurement and first-principles calculations

International Nuclear Information System (INIS)

Emel'yanenko, Vladimir N.; Zaitsau, Dzmitry H.; Verevkin, Sergey P.; Heintz, Andreas

2011-01-01

Highlights: → We studied the ionic liquid 1-ethanol-3-methylimidazolium dicyanamide. → Combustion calorimetry was used to derive enthalpy of formation in the liquid state. → Composite G3(MP2) method used to compute enthalpy of formation in the gaseous phase. → Enthalpy of vaporization was derived as the difference. → The liquid phase enthalpy of formation presumably obey the group additivity rules. - Abstract: The standard molar enthalpy of formation Δ f H m o (l) of the ionic liquid 1-ethanol-3-methylimidazolium dicyanamide has been determined at 298.15 K by means of combustion calorimetry. First-principles calculations of the enthalpy of formation in the gaseous phase have been performed for the ionic species using the composite G3(MP2) method. The combination of combustion calorimetry with the high-level quantum-chemical calculations allows to estimate the molar enthalpy of vaporization of the ionic liquid under study. It has been established, that the liquid phase enthalpy of formation of this ionic liquid presumably obeys the group additivity rules.

Studies on the solvation dynamics of coumarin 153 in 1-ethyl-3-methylimidazolium alkylsulfate ionic liquids: dependence on alkyl chain length.

Science.gov (United States)

Das, Sudhir Kumar; Sarkar, Moloy

2012-08-06

Steady-state and time-resolved fluorescence behavior of coumarin 153 (C153) is investigated in a series of 1-ethyl-3-methylimidazolium alkylsulfate ([C(2)mim][C(n)OSO(3)]) ionic liquids differing only in the length of the linear alkyl chain (n = 4, 6, and 8) in the anion. The aim of the present study is to understand the role of alkyl chain length in solute rotation and solvation dynamics of C153 in these ionic liquids. The blueshift observed in the steady-state absorption and emission maxima of C153 on going from the C(4)OSO(3) to the C(8)OSO(3) system indicates increasing nonpolar character of the microenvironment of the solute with increasing length of the alkyl side chain of the anion of the ionic liquids. The average solvation time is also found to increase on changing the substituent from butyl to octyl, and this is attributed to the increase in the bulk viscosity of the ILs. A steady blueshift of the time-zero maximum of the fluorescence spectrum with increasing alkyl chain length also indicates that the probe molecule experiences a less polar environment in the early part of the dynamics. Rotational dynamics of C153 are also analyzed by using the Stokes-Einstein-Debye (SED), Gierer-Wirtz (GW), and Dote-Kivelson-Schwartz (DKS) theories. Analyses of the results seem to suggest decoupling of the rotational motion of the probe from solvent viscosity. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Experimental study of the density and viscosity of 1-ethyl-3-methylimidazolium ethyl sulfate

International Nuclear Information System (INIS)

Schmidt, H.; Stephan, M.; Safarov, J.; Kul, I.; Nocke, J.; Abdulagatov, I.M.; Hassel, E.

2012-01-01

Highlights: ► Density of the ionic liquid [EMIM][EtSO 4 ]. ► Viscosity of the ionic liquid [EMIM][EtSO 4 ]. ► Thermodynamic properties of ionic liquid [EMIM][EtSO 4 ]. ► Equation of state of ionic liquid [EMIM][EtSO 4 ]. - Abstract: Density and viscosity of 1-ethyl-3-methylimidazolium ethyl sulfate [EMIM][EtSO 4 ] have been measured over the temperature range from (283.15 to 413.15) K and at pressures up to 140 MPa and in the temperature range from (283.15 to 373.15) K at 0.1 MPa, respectively. The expanded uncertainty of the density, pressure, temperature, and viscosity measurements at the 95% confidence level with a coverage factor of k = 2 is estimated to be (0.01 to 0.08)%, 0.1%, 15 mK, and 0.35%, respectively. The measurements were carried out with an Anton–Paar DMA HPM vibration-tube densimeter and a fully automated SVM 3000 Anton–Paar rotational Stabinger viscometer. The vibration-tube densimeter was calibrated using various reference fluids, double-distilled water, methanol, toluene, and aqueous NaCl solutions. An empiric equation of state for [EMIM][EtSO 4 ] has been developed using the measured (p, ρ, T) data. This equation was used to calculate the various thermodynamic properties of the IL and for compare with measured properties (speed of sound and enthalpy). Theoretically based Arrhenius–Andrade and Vogel–Tamman–Fulcher type equations were use to describe of the temperature dependence of measured viscosities for [EMIM][EtSO 4 ]. All measured properties were detailed compared with the reported data by other author.

Binary and ternary (liquid + liquid) equilibrium for {methylcyclohexane (1) + toluene (2) + 1-hexyl-3-methylimidazolium tetracyanoborate (3)/1-butyl-3-methylimidazolium tetracyanoborate (3)}

International Nuclear Information System (INIS)

Gutierrez, Juan Pablo; Meindersma, Wytze; Haan, Andre B. de

2011-01-01

Highlights: → Binary and ternary extractions for two ionic liquids with organic compounds were measured. → NRTL and UNIQUAC thermodynamic models were used to fit the experimental data. → UNIQUAC model gives better predictions than the NRTL model. → Ionic liquids showed interesting properties as solvents to be applied in separation processes. - Abstract: This paper focuses on the study of the solubility behaviour of 1-hexyl-3-methylimidazolium tetracyanoborate [HMIM][TCB] and 1-butyl-3-methylimidazolium tetracyanoborate [BMIM][TCB] in combination with methylcyclohexane and toluene as representatives for non-aromatic and aromatic components. Binary and ternary (liquid + liquid) equilibrium data were collected at three different temperatures and at atmospheric pressure (0.1 MPa). The experimental data were well-correlated with the NRTL and UNIQUAC thermodynamic models; however, the UNIQUAC model gave better predictions than the NRTL, with a root mean square error below 0.97%. The non-aromatic/aromatic selectivities of the ionic liquids make them suitable solvents to be used in extractive distillation processes.

Vapour pressures and osmotic coefficients of binary mixtures of 1-ethyl-3-methylimidazolium ethylsulfate and 1-ethyl-3-methylpyridinium ethylsulfate with alcohols at T = 323.15 K

International Nuclear Information System (INIS)

Calvar, Noelia; Gonzalez, Begona; Dominguez, Angeles; Macedo, Eugenia A.

2009-01-01

Osmotic coefficients of binary mixtures containing alcohols (ethanol, 1-propanol, and 2-propanol) and the ionic liquids 1-ethyl-3-methylimidazolium ethylsulfate and 1-ethyl-3-methylpyridinium ethylsulfate were determined at T = 323.15 K. Vapour pressure and activity coefficients of the studied systems were calculated from experimental data. The extended Pitzer model modified by Archer, and the modified NRTL model (MNRTL) were used to correlate the experimental data, obtaining standard deviations lower than 0.012 and 0.031, respectively. The mean molal activity coefficients and the excess Gibbs free energy of the studied binary mixtures were calculated from the parameters obtained with the extended Pitzer model of Archer.

Charging/discharging kinetics of poly(3,4-ethylenedioxythiophene) in 1-ethyl-3-methylimidazolium bis-(trifluoromethylsulfonyl)imide ionic liquid under galvanostatic conditions

Energy Technology Data Exchange (ETDEWEB)

Randriamahazaka, H. [Equipe Interactions et Dynamiques aux Interfaces, Laboratoire de Physico-Chimie des Polymeres et des Interfaces (LPPI) E.A. 2528, Universite de Cergy-Pontoise, 5 mail Gay Lussac, Neuville sur Oise, 95031 Cergy-Pontoise Cedex (France); Plesse, C.; Teyssie, D.; Chevrot, C. [Laboratoire de Physico-Chimie des Polymeres et des Interfaces (LPPI) E.A. 2528, Universite de Cergy-Pontoise, 5 mail Gay Lussac, Neuville sur Oise, 95031 Cergy-Pontoise Cedex (France)

2005-08-01

The constant current charging/discharging experiments of poly(3,4-ethylenedioxythiophene) (PEDOT), modified electrodes in room temperature ionic liquid, for instance 1-ethyl-3-methylimidazolium bis-(trifluoromethylsulfonyl)imide, were performed for two types of cell configurations, three and two-electrode cells. In each case, a linear variation of the voltage with respect to time was observed. The electrochemical responses were analyzed in term of a series combination of a resistance R and a capacitor C. Accordingly, the capacitance of the modified electrodes was determined. One observed a linear variation of the capacitance as a function of the amount of PEDOT. This capacitance described the chemical capacitance of PEDOT that reflected the capability of the system to accept or release additional charge carriers on a given variation of the chemical potential. Also, the electrochemical response during constant current charging/discharging experiments for two-electrode cell in which the same amount of PEDOT was deposited on each electrode showed a type I electrochemical supercapacitor response. This kind of an electrochemical chain allowed us to mimic and to analyze the electrical responses of an electrochemical actuator based on an interpenetrating polymer networks containing PEDOT that was able to work in air. (author)

The 1-ethyl-3-methylimidazolium bis(trifluoro-methylsulfonyl)-imide ionic liquid nanodroplets on solid surfaces and in electric field: A molecular dynamics simulation study

Science.gov (United States)

Dong, Dengpan; Vatamanu, Jenel P.; Wei, Xiaoyu; Bedrov, Dmitry

2018-05-01

Atomistic molecular dynamics simulations were conducted to study the wetting states of 1-ethyl-3-methylimidazolium bis(trifluoro-methylsulfonyl)-imide ionic liquid (IL) nanodroplets on surfaces with different strengths of van der Waals (VDW) interactions and in the presence of an electric field. By adjusting the depth of Lennard-Jones potential, the van der Waals interaction between the solid surface and ionic liquid was systematically varied. The shape of the droplets was analyzed to extract the corresponding contact angle utilized to characterize wetting states of the nanodroplets. The explored range of surface-IL interactions allowed contact angles ranging from complete IL spreading on the surface to poor wettability. The effect of the external electrical field was explored by adding point charges to the surface atoms. Systems with two charge densities (±0.002 e/atom and ±0.004 e/atom) that correspond to 1.36 V/nm and 2.72 V/nm electric fields were investigated. Asymmetrical wetting states were observed for both cases. At 1.36 V/nm electric field, contributions of IL-surface VDW interactions and Coulombic interactions to the wetting state were competitive. At 2.72 V/nm field, electrostatic interactions dominate the interaction between the nanodroplet and surface, leading to enhanced wettability on all surfaces.

Alkylsulfate-based ionic liquids in the liquid–liquid extraction of aromatic hydrocarbons

International Nuclear Information System (INIS)

García, Silvia; Larriba, Marcos; García, Julián; Torrecilla, José S.; Rodríguez, Francisco

2012-01-01

Highlights: ► Values of α 2,1 for the four R-SO 4 ionic liquids are higher than those of sulfolane. ► Values of D 2 for all the ionic liquids are lower than those of sulfolane. ► Values of D 2 for [emim][C 2 H 5 SO 4 ] are the highest among the R-SO 4 ionic liquids. - Abstract: The (liquid + liquid) equilibrium data (LLE) for the extraction of toluene from heptane with different ionic liquids (ILs) based on the alkylsulfate anion (R-SO 4 ) was determined at T = 313.2 K and atmospheric pressure. The effect of more complex R-SO 4 anions on capacity of extraction and selectivity in the liquid–liquid extraction of toluene from heptane was studied. The ternary systems were formed by {heptane + toluene + 1,3-dimethylimidazolium methylsulfate ([mmim][CH 3 SO 4 ]), 1-ethyl-3-methylimidazolium hydrogensulfate ([emim][HSO 4 ]), 1-ethyl-3-methylimidazolium methylsulfate ([emim][CH 3 SO 4 ]), or 1-ethyl-3-methylimidazolium ethylsulfate ([emim][C 2 H 5 SO 4 ])}. The degree of quality of the experimental LLE data was ascertained by applying the Othmer–Tobias correlation. The phase diagrams for the ternary systems were plotted, and the tie lines correlated with the NRTL model compare satisfactorily with the experimental data.

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

Science.gov (United States)

Chen, Fengli; Hou, Kexin; Li, Shuangyang; Zu, Yuangang; Yang, Lei

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 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. PMID:24782942

Solubility of carbon dioxide in the low-viscosity ionic liquid 1-hexyl-3-methylimidazolium tetracyanoborate

NARCIS (Netherlands)

Mota Martinez, M.T.; Althuluth, M.A.M.; Kroon, M.C.; Peters, C.J.

2012-01-01

The solubility of carbon dioxide (CO2) in a new low-viscosity and non-fluorinated ionic liquid, 1-hexyl-3-methylimidazolium tetracyanoborate ([hmim][TCB]), has been studied experimentally using a synthetic method. Bubble point pressures (up to 12.34 MPa) of the system CO2 + [hmim][TCB] are reported

Dissolution of agro-waste in ionic liquids

International Nuclear Information System (INIS)

Lee, Kiat Moon; Ngoh, Gek Cheng; Chua, Adeline Seak May

2010-01-01

Full text: There are abundant of agro-wastes being produced in Malaysia. One of the largely produced agro wastes is the sago hampas. It is known as a strong environmental pollutant due to its cellulosic fibrous material. However, the presence of the starch, cellulose and hemicelluloses in the hampas can be converted into valuable products such as reducing sugars. Hence, this study was performed to investigate the ability of ionic liquids in hydrolysing the ligno celluloses biomass into reducing sugars. Three types of ionic liquids were used, 1-butyl-3-methylimidazolium chloride (BMIM Cl), 1-ethyl-3- methylimidazolium acetate (EMIM Ac) and 1-ethyl-3-methylimidazolium diethyl phosphate (EMIM DEP). The reaction was performed by heating the reaction mixture of sago hampas and ionic liquids at 100 degree Celsius. The concentrations of reducing sugars in the hydrolysates were determined by DNS method. Maximum concentration of reducing sugars were 0.424, 0.299, 0.260 mg/ml for BmimCl, EmimAc and EmimDEP respectively. These concluded that the selected ionic liquids were inefficient in hydrolysing the sago hampas to reducing sugars. (author)

The gaseous enthalpy of formation of the ionic liquid 1-butyl-3-methylimidazolium dicyanamide from combustion calorimetry, vapor pressure measurements, and ab initio calculations.

Science.gov (United States)

Emel'yanenko, Vladimir N; Verevkin, Sergey P; Heintz, Andreas

2007-04-04

Ionic liquids are attracting growing interest as alternatives to conventional molecular solvents. Experimental values of vapor pressure, enthalpy of vaporization, and enthalpy of formation of ionic liquids are the key thermodynamic quantities, which are required for the validation and development of the molecular modeling and ab initio methods toward this new class of solvents. In this work, the molar enthalpy of formation of the liquid 1-butyl-3-methylimidazolium dicyanamide, 206.2 +/- 2.5 kJ.mol-1, was measured by means of combustion calorimetry. The molar enthalpy of vaporization of 1-butyl-3-methylimidazolium dicyanamide, 157.2 +/- 1.1 kJ.mol-1, was obtained from the temperature dependence of the vapor pressure measured using the transpiration method. The latter method has been checked with measurements of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide, where data are available from the effusion technique. The first experimental determination of the gaseous enthalpy of formation of the ionic liquid 1-butyl-3-methylimidazolium dicyanamide, 363.4 +/- 2.7 kJ.mol-1, from thermochemical measurements (combustion and transpiration) is presented. Ab initio calculations of the enthalpy of formation in the gaseous phase have been performed for 1-butyl-3-methylimidazolium dicyanamide using the G3MP2 theory. Excellent agreement with experimental results has been observed. The method developed opens a new way to obtain thermodynamic properties of ionic liquids which have not been available so far.

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

Science.gov (United States)

Merouani, Slimane; Hamdaoui, Oualid; Haddad, Boumediene

2018-03-01

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

Degradation of 1-butyl-3-methylimidazolium chloride ionic liquid in a Fenton-like system

International Nuclear Information System (INIS)

Siedlecka, E.M.; Mrozik, W.; Kaczynski, Z.; Stepnowski, P.

2008-01-01

The study examined the usefulness of a Fenton-like system for the degradation of ionic liquid residues in water. The ionic liquid was oxidized in a dilute aqueous solution of 1-butyl-3-methylimidazolium chloride (bmimCl). The ionic liquid decomposes readily and rapidly in aqueous solution by chemical degradation in a Fenton-like system. Under chosen conditions the initial bmimCl solution was reduced by a factor of 0.973 within 90 min. Additional results showed that bmimCl degradations in a Fenton-like system in excess H 2 O 2 could be interpreted as a combined oxidation-reduction mechanism. Preliminary investigations of the mechanism of such degradations have indicated that initial OH· radicals can attack any one of the three carbon atoms on the imidazolium ring. The intermediates of this reaction may be mono- di- or amino- carboxylic acids

Enhanced CO2 capture in binary mixtures of 1-alkyl-3-methylimidazolium tricyanomethanide ionic liquids with water

NARCIS (Netherlands)

Romanos, G.E.; Zubeir, L.F.; Likodimos, V.; Falaras, P.; Kroon, M.C.; Iliev, B.; Adamova, G.; Schubert, T.J.S.

2013-01-01

The absorption of carbon dioxide and water in the 1-butyl-3-methylimidazoliun tricyanomethanide ([C4C1im][TCM]) and 1-octyl-3-methylimidazolium tricyanomethanide ([C8C1im][TCM]) ionic liquids (ILs) was systematically investigated for the first time as a function of the H2O content by means of a

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

International Nuclear Information System (INIS)

Wang Silu; Jacquemin, Johan; Husson, Pascale; Hardacre, Christopher; Costa Gomes, Margarida 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 ([C 1 C 4 Im][BF 4 ]) and 1-ethyl-3-methylimidazolium ethylsulfate ([C 1 C 2 Im][EtSO 4 ])) and five ionic liquids only partially miscible with water (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C 1 C 2 Im][NTf 2 ]), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C 1 C 4 Im][NTf 2 ]), 1-butyl-3-methylimidazolium hexafluorophosphate ([C 1 C 4 Im][PF 6 ]), 1-butyl-3-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([C 1 C 4 Pyrro][NTf 2 ]), and butyltrimethylammonium bis(trifluoromethylsulfonyl)imide ([N 4111 ][NTf 2 ])) were chosen. Small excess volumes (less than 0.5 cm 3 . 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 {[C 1 C 2 Im][EtSO 4 ] + water}, positive excess molar volumes were calculated. Finally, an increase of the non-ideality character is observed for all the systems as temperature increases.

Strong luminescence of rare earth compounds in ionic liquids: Luminescent properties of lanthanide(III) iodides in the ionic liquid 1-dodecyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide

International Nuclear Information System (INIS)

Mudring, Anja-Verena; Babai, Arash; Arenz, Sven; Giernoth, Ralf; Binnemans, K.; Driesen, Kris; Nockemann, Peter

2006-01-01

Purposely designed ionic liquids can be excellent solvents for spectroscopic studies of rare earth compounds. Absorption, excitation and emission spectra of LnI 3 (Ln = Nd, Dy and Tb) in the ionic liquid 1-dodecyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide are presented. Electronic transitions were assigned from the energy level diagrams for Ln(III). Emission lifetimes for DyI 3 in [C 12 mim][Tf 2 N] are discussed. Traces of water dramatically reduce the otherwise long lifetimes and comparatively high quantum yields

Desulfurization of oxidized diesel using ionic liquids

Science.gov (United States)

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

2014-10-01

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

Electron density analysis of 1-butyl-3-methylimidazolium chloride ionic liquid.

Science.gov (United States)

del Olmo, Lourdes; Morera-Boado, Cercis; López, Rafael; García de la Vega, José M

2014-06-01

An analysis of the electron density of different conformers of the 1-butyl-3-methylimidazolium chloride (bmimCl) ionic liquid by using DFT through the BVP86 density functional has been obtained within the framework of Bader's atom in molecules (AIM), localized orbital locator (LOL), natural bond orbital (NBO), and deformed atoms in molecules (DAM). We also present an analysis of the reduced density gradients that deliver the non-covalent interaction regions and allow to understand the nature of intermolecular interactions. The most polar conformer can be characterized as ionic by AIM, LOL, and DAM methods while the most stable and the least polar shows shared-type interactions. The NBO method allows to comprehend what causes the stabilization of the most stable conformer based on analysis of the second-order perturbative energy and the charge transferred among the natural orbitals involved in the interaction.

Natural gas purification using supported ionic liquid membrane

NARCIS (Netherlands)

Althuluth, M.A.M.; Overbeek, J.P.; Wees, H.J.; Zubeir, L.F.; Haije, W.G.; Berrouk, A.S.; Peters, C.J.; Kroon, M.C.

2015-01-01

This paper examines the possibility of the application of a supported ionic liquid membrane (SILM) for natural gas purification. The ionic liquid (IL) 1-ethyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate ([emim][FAP]) was impregnated successfully in the ¿-alumina layer of a tubular

Ionic liquids as solvents for liquid scintillation technology. Čerenkov counting with 1-Butyl-3-Methylimidazolium Chloride

International Nuclear Information System (INIS)

Mirenda, Martín; Rodrigues, Darío; Arenillas, Pablo; Gutkowski, Karin

2014-01-01

We report the detection of the Čerenkov luminescence after the incorporation of a few droplets of a physiological solution of 2-deoxi-2( 18 F)fluorine-D-glucose into the ionic liquid 1-Butyl-3-Methylimidazolium Chloride (BmimCl). The phenomenon is attributed to the β + particles having energy above the threshold energy value for the Čerenkov radiation in this medium. The presence of another type of radiation that could eventually cause coincidences in the photodetectors was safely discarded. We show that this property serves to determine the activity of a 18 F solution by means of the novel TDCR–Čerenkov technique. The results were compared with those obtained from the classic TDCR scintillation method using a commercial scintillation cocktail. The activity values obtained from both methods were found to be virtually identical within the experimental uncertainties. The fact that high energy β particles in BmimCl generates Čerenkov photons makes this ionic liquid a promising compound for future research in detection and quantification of ionizing radiation, and it provides a potential alternative for applications in nuclear technology. - Highlights: • Čerenkov luminescence was detected when 18 F was dissolved in 1-Butyl-3-Methylimidazolium Chloride (BmimCl) ionic liquid. • The presence of another type of radiation that could eventually cause coincidences in the photodetectors was safely discarded. • Čerenkov luminescence serves to determine the activity of a 18 F solution by means of TDCR–Čerenkov technique. • Some advantages of the use of BmimCl as solvent for Čerenkov counting were listed

Alternative route to metal halide free ionic liquids

International Nuclear Information System (INIS)

Takao, Koichiro; Ikeda, Yasuhisa

2008-01-01

An alternative synthetic route to metal halide free ionic liquids using trialkyloxonium salt is proposed. Utility of this synthetic route has been demonstrated by preparing 1-ethyl-3-methylimidazolium tetrafluoroborate ionic liquid through the reaction between 1-methylimidazole and triethyloxonium tetra-fluoroborate in anhydrous ether. (author)

Measurement of activity coefficients at infinite dilution of organic solutes in the ionic liquid 1-ethyl-3-methylimidazolium 2-(2-methoxyethoxy) ethylsulfate at T = (308.15, 313.15, 323.15 and 333.15) K using gas + liquid chromatography

International Nuclear Information System (INIS)

Bahadur, Indra; Govender, Byron Bradley; Osman, Khalid; Williams-Wynn, Mark D.; Nelson, Wayne Michael; Naidoo, Paramespri; Ramjugernath, Deresh

2014-01-01

Highlights: • Activity coefficients at infinite dilution measured in the ionic liquid [EMIM] + [MDEGSO 4 ] − . • 28 organic solutes investigated at T = (308.15, 313.15, 323.15 and 333.15) K using glc. • Selectivities for selected hexane/benzene separations compared to other IL’s and solvents. • IL shows higher selectivities than conventional solvents such as NMP, NFM, and sulfolane. -- Abstract: In this study, the interactions between volatile organic compounds and the ionic liquid (IL) 1-ethyl-3-methylimidazolium 2-(2-methoxyethoxy) ethylsulfate [EMIM] + [MDEGSO 4 ] − were investigated using gas + liquid chromatography measurements. The activity coefficients at infinite dilution γ 13 ∞ were determined for 28 polar and non-polar organic solutes (alkanes, cycloalkanes, alkenes, alkynes, aromatic compounds, alcohols, and ketones) in 1-ethyl-3-methylimidazolium 2-(2-methoxyethoxy) ethylsulfate at T = (308.15, 313.15, 323.15 and 333.15) K. Packed columns with phase loadings of 0.27 and 0.37 mass fraction of the IL in the stationary phase were employed to obtain γ 13 ∞ values at each temperature. Density and refractive index values were also measured for the pure IL at P = 0.1 MPa and at the experimental temperatures. Partial molar excess enthalpies at infinite dilution ΔH 1 E,∞ were calculated for the solutes from the temperature dependency of the γ 13 ∞ values. The uncertainties in the activity coefficient at infinite dilution were critically evaluated and estimated on average to be ±5.3%. Selectivity values at infinite dilution S ij ∞ for the hexane/benzene separation were also calculated at T = 308.15 K. The selectivity S ij ∞ value of the IL investigated in this study is approximately 3.7 times greater than that for NMP, 2.6 times greater than that for NFM, and 2.3 times greater than that for sulfolane. These results indicate the potential use of this IL in extractive separation processes

Relationship between lignocellulosic biomass dissolution and physicochemical properties of ionic liquids composed of 3-methylimidazolium cations and carboxylate anions.

Science.gov (United States)

Moyer, Preenaa; Smith, Micholas Dean; Abdoulmoumine, Nourredine; Chmely, Stephen C; Smith, Jeremy C; Petridis, Loukas; Labbé, Nicole

2018-01-24

The ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate ([EMIM]Acetate) has been widely used for biomass processing, i.e., to pretreat, activate, or fractionate lignocellulosic biomass to produce soluble sugars and lignin. However, this IL does not achieve high biomass solubility, therefore minimizing the efficiency of biomass processing. In this study, [EMIM]Acetate and three other ILs composed of different 3-methylimidazolium cations and carboxylate anions ([EMIM]Formate, 1-allyl-3-methylimidazolium ([AMIM]) formate, and [AMIM]Acetate) were analyzed to relate their physicochemical properties to their biomass solubility performance. While all four ILs are able to dissolve hybrid poplar under fairly mild process conditions (80 °C and 100 RPM stirring), [AMIM]Formate and [AMIM]Acetate have particularly increased biomass solubility of 40 and 32%, respectively, relative to [EMIM]Acetate. Molecular dynamics simulations suggest that strong interactions between IL and specific plant biopolymers may contribute to this enhanced solubilization, as the calculated second virial coefficients between ILs and hemicellullose are most favorable for [AMIM]Formate, matching the trend of the experimental solubility measurements. The simulations also reveal that the interactions between the ILs and hemicellulose are an important factor in determining the overall biomass solubility, whereas lignin-IL interactions were not found to vary significantly, consistent with literature. The combined experimental and simulation studies identify [AMIM]Formate as an efficient biomass solvent and explain its efficacy, suggesting a new approach to rationally select ionic liquid solvents for lignocellulosic deconstruction.

Relationship between lignocellulosic biomass dissolution and physicochemical properties of ionic liquids composed of 3-methylimidazolium cations and carboxylate anions

Energy Technology Data Exchange (ETDEWEB)

Moyer, Preenaa [Univ. of Tennessee, Knoxville, TN (United States). Center for Renewable Carbon. Dept. of Biosystems Engineering and Soil Science; Smith, Micholas Dean [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Molecular Biophysics; Univ. of Tennessee, Knoxville, TN (United States). Dept. of Biochemistry and Cellular and Molecular Biology; Abdoulmoumine, Nourredine [Univ. of Tennessee, Knoxville, TN (United States). Center for Renewable Carbon. Dept. of Biosystems Engineering and Soil Science; Chmely, Stephen C. [Univ. of Tennessee, Knoxville, TN (United States). Center for Renewable Carbon; Smith, Jeremy C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Molecular Biophysics; Univ. of Tennessee, Knoxville, TN (United States). Dept. of Biochemistry and Cellular and Molecular Biology; Petridis, Loukas [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Molecular Biophysics; Univ. of Tennessee, Knoxville, TN (United States). Dept. of Biochemistry and Cellular and Molecular Biology; Labbé, Nicole [Univ. of Tennessee, Knoxville, TN (United States). Center for Renewable Carbon

2018-01-02

The ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate ([EMIM]Acetate) has been widely used for biomass processing, i.e., to pretreat, activate, or fractionate lignocellulosic biomass to produce soluble sugars and lignin. However, this IL does not achieve high biomass solubility, therefore minimizing the efficiency of biomass processing. In this paper, [EMIM]Acetate and three other ILs composed of different 3-methylimidazolium cations and carboxylate anions ([EMIM]Formate, 1-allyl-3-methylimidazolium ([AMIM]) formate, and [AMIM]Acetate) were analyzed to relate their physicochemical properties to their biomass solubility performance. While all four ILs are able to dissolve hybrid poplar under fairly mild process conditions (80 °C and 100 RPM stirring), [AMIM]Formate and [AMIM]Acetate have particularly increased biomass solubility of 40 and 32%, respectively, relative to [EMIM]Acetate. Molecular dynamics simulations suggest that strong interactions between IL and specific plant biopolymers may contribute to this enhanced solubilization, as the calculated second virial coefficients between ILs and hemicellullose are most favorable for [AMIM]Formate, matching the trend of the experimental solubility measurements. The simulations also reveal that the interactions between the ILs and hemicellulose are an important factor in determining the overall biomass solubility, whereas lignin–IL interactions were not found to vary significantly, consistent with literature. Finally, the combined experimental and simulation studies identify [AMIM]Formate as an efficient biomass solvent and explain its efficacy, suggesting a new approach to rationally select ionic liquid solvents for lignocellulosic deconstruction.

Effect of temperature on the physical properties of 1-butyl-3-methylimidazolium based ionic liquids with thiocyanate and tetrafluoroborate anions, and 1-hexyl-3-methylimidazolium with tetrafluoroborate and hexafluorophosphate anions

International Nuclear Information System (INIS)

Vakili-Nezhaad, Gholamreza; Vatani, Mostafa; Asghari, Morteza; Ashour, Ibrahim

2012-01-01

Highlights: ► Four ionic liquids named: [BMIM][SCN], [BMIM][BF 4 ], [HMIM][BF 4 ], and [HMIM][PF 6 ] are investigated. ► Density, refractive index, surface tension, dynamic viscosity, and kinematic viscosity of the ionic liquids are measured. ► The measured data was correlated with temperature finding their decrease with rising temperature. ► The volumetric properties of the ionic liquids are calculated from the experimental values of density at T = 298.15 K. ► Correlation between the properties was carried out by the least square method using several empirical equations. - Abstract: The effect of temperature on the physical properties of some ionic liquids was investigated. Density, refractive index, surface tension, dynamic and kinematic viscosities of 1-butyl-3-methylimidazolium based ionic liquids with thiocyanate and tetrafluoroborate, and 1-hexyl-3-methylimidazolium with tetrafluoroborate and hexafluorophosphate anions were measured at various temperatures (density from T = (278.15 to 363.15) K, refractive index from (293.15 to 343.15) K, surface tension from (283.15 to 333.15) K, dynamic viscosity from (283.15 to 368.15) K, and kinematic viscosity from (298.15 to 363.15) K). The volumetric properties for the ionic liquids were also calculated from the experimental values of the density at T = 298.15 K. The Vogel–Fulcher–Tammann (VFT) equation was applied to correlate experimental values of dynamic and kinematic viscosities as a function of temperature. As well, the relation between density and refractive index was correlated satisfactorily with several empirical equations such as Lorentz–Lorenz, Dale–Gladstone, Eykman, Oster, Arago–Biot, Newton and Modified–Eykman. Finally, the relation between surface tension and viscosity was investigated and the parachor method was used to predict density, refractive index and surface tension of the ionic liquids.

Correlations between phase behaviors and ionic conductivities of (ionic liquid + alcohol) systems

International Nuclear Information System (INIS)

Park, Nam Ku; Bae, Young Chan

2010-01-01

To understand the basic properties of ionic liquids (ILs), we examined the phase behavior and ionic conductivity characteristics using various compositions of different ionic liquids (1-ethyl-3-methylimidazolium hexafluorophosphate [emim] [PF6] and 1-benzyl-3-methylimidazolium hexafluorophosphate [bzmim] [PF6]) in several different alcohols (ethanol, propanol, 1-butanol, 2-butanol, and hexanol). We conducted a systematic study of the impact of different factors on the phase behavior of imidazolium-based ionic liquids in alcohols. Using a new experimental method with a liquid electrolyte system, we observed that the ionic conductivity of the ionic liquid/alcohol was sensitive to the surrounding temperature. We employed Chang et al.'s thermodynamic model [Chang et al. (1997, 1998) ] based on the lattice model. The obtained co-ordinated unit parameter from this model was used to describe the phase behavior and ionic conductivities of the given system. Good agreement with experimental data of various alcohol and ILs systems was obtained in the range of interest.

Ternary liquid-liquid equilibria for mixtures of toluene + n-heptane + an ionic liquid

NARCIS (Netherlands)

Meindersma, G.W.; Podt, J.G.; de Haan, A.B.

2006-01-01

This research has been focused on a study of sulfolane and four ionic liquids as solvents in liquid–liquid extraction. Liquid–liquid equilibria data were obtained for mixtures of (sulfolane or 4-methyl-N-butylpyridinium tetrafluoroborate ([mebupy]BF4) or 1-ethyl-3-methylimidazolium ethylsulfate

Effect of lithium tetrafluoroborate on the solubility of carbon dioxide in the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate

NARCIS (Netherlands)

Durano Arno, S.; Lucas, S.; Shariati - Sarabi, A.; Peters, C.J.

2012-01-01

In this work, the phase behavior of the ternary system of carbon dioxide +1-butyl-3-methylimidazolium tetrafluoroborate + lithium tetrafluoroborate has been investigated. Mixtures of known concentrations of the salt, ionic liquid and carbon dioxide were prepared and their bubble point pressures were

Imidazolium ionic liquids as solvents for cerium(IV)-mediated oxidation reactions

OpenAIRE

Mehdi, Hasan; Bodor, Andrea; Lantos, Diana; Horváth, István T; De Vos, Dirk; Binnemans, Koen

2007-01-01

Use of imidazolium ionic liquids as solvents for organic transformations with tetravalent cerium salts as oxidizing agents was evaluated. Good solubility was found for ammonium hexanitratocerate(IV) (ceric ammonium nitrate, CAN) and cerium(IV) triflate in 1-alkyl-3-methylimidazolium triflate ionic liquids. Oxidation of benzyl alcohol to benzaldehyde in 1-ethyl-3-methylimidazolium triflate was studied by in-situ FTIR spectroscopy and 13C NMR spectroscopy on carbon-13-labeled benzyl alcohol. Ca...

Effect of Brönsted acidic ionic liquid 1-(1-propylsulfonic)-3-methylimidazolium chloride on growth and co-fermentation of glucose, xylose and arabinose by Zymomonas mobilis AX101.

Science.gov (United States)

Gyamerah, M; Ampaw-Asiedu, M; Mackey, J; Menezes, B; Woldesenbet, S

2018-06-01

The potential of large-scale lignocellulosic biomass hydrolysis to fermentable sugars using ionic liquids has increased interest in this green chemistry route to fermentation for fuel-ethanol production. The ionic liquid 1-(1-propylsulfonic)-3-methylimidazolium chloride compared to other reported ionic liquids has the advantage of hydrolysing lignocellulosic biomass to reducing sugars at catalytic concentrations (≤0·032 mol l -1 ) in a single step. However, effects of this ionic liquid on co-fermentation of glucose, xylose and arabinose to ethanol by recombinant Zymomonas mobilisAX101 has not been studied. Authentic glucose, xylose and arabinose were used to formulate fermentation media at varying catalytic 1-(1-propylsulfonic)-3-methylimidazolium chloride concentrations for batch co-fermentation of the sugars using Z. mobilisAX101. The results showed that at 0·008, 0·016 and 0·032 mol l -1 ionic liquid in the culture medium, cell growth decreased by 10, 27 and 67% respectively compared to the control. Ethanol yields were 62·6, 61·8, 50·5 and 23·1% for the control, 0·008, 0·016 and 0·032 mol l -1 ionic liquid respectively. The results indicate that lignocellulosic biomass hydrolysed using 0·008 mol l -1 of 1-(1-propylsulfonic)-3-methylimidazolium chloride would eliminate an additional separation step and provide a ready to use fermentation substrate. This is the first reported study of the effect of the Brönsted acidic ionic liquid 1-(1-propylsulfonic)-3-methylimidazolium chloride on growth and co-fermentation of glucose, xylose and arabinose by Zymomonas mobilisAX101 in batch culture. Growth on and co-fermentation of the sugars by Z. mobilisAX 101 with no significant inhibition by the ionic liquid at the same catalytic amounts of 0·008 mol l -1 used to hydrolyse lignocellulosic biomass to reducing sugars overcome two major hurdles that adversely affect the process economics of large-scale industrial cellulosic fuel ethanol production

Interaction of copper with dinitrogen tetroxide in 1-butyl-3-methylimidazolium-based ionic liquids.

Science.gov (United States)

Morozov, I V; Deeva, E B; Glazunova, T Yu; Troyanov, S I; Guseinov, F I; Kustov, L M

2017-03-27

Ionic liquids that are stable toward oxidation and nitration and are based on the 1-n-butyl-3-methylimidazolium cation (BMIm + ) can be used as solvents and reaction media for copper dissolution in liquid dinitrogen tetraoxide N 2 O 4 . The ionic liquid not only favors the dissociation of N 2 O 4 into NO + and NO 3 - , but also takes part in the formation of different crystalline products. Thus, NO[BF 4 ], NO[Cu(NO 3 ) 3 ] and (BMIm) 2 [Cu 2 (CF 3 COO) 6 ] were prepared using (BMIm)A, A - = [BF 4 ] - , (CF 3 SO 2 ) 2 N - , CF 3 COO - , respectively. The formation of a certain product is determined by the nature of the anion A - and the relative solubility of the reaction products in the ionic liquid. Crystals of NO[BF 4 ] were also prepared directly from a mixture of N 2 O 4 and BMImBF 4 . According to XRD single-crystal structure analysis, the structure of NO[BF 4 ] consists of tetrahedral [BF 4 ] - anions and nitrosonium NO + cations; the formation of these ions prove the heterolytic dissociation of N 2 O 4 dissolved in the ionic liquid. The crystal structure of the earlier unknown binuclear copper trifluoroacetate (BMIm) 2 [Cu 2 (CF 3 COO) 6 ] were determined by X-ray diffraction. The peculiarity of this dimer compared to the majority of known dimeric copper(ii) carboxylates is the unusually long CuCu distance (3.15 Å), with Cu(ii) ions demonstrating an atypical coordination of a distorted trigonal bipyramid formed by five O atoms of five trifluoroacetate groups.

Self-aggregation of bio-surfactants within ionic liquid 1-ethyl-3-methylimidazolium bromide: A comparative study and potential application in antidepressants drug aggregation

Science.gov (United States)

Banjare, Manoj Kumar; Behera, Kamalakanta; Kurrey, Ramsingh; Banjare, Ramesh Kumar; Satnami, Manmohan L.; Pandey, Siddharth; Ghosh, Kallol K.

2018-06-01

Aggregation behavior of bio-surfactants (BS) sodium cholate (NaC) and sodium deoxycholate (NaDC) within aqueous solution of ionic liquid (IL) 1-ethyl-3-methylimidazolium bromide [Emim][Br] has been investigated using surface tension, conductivity, steady state fluorescence, FT-IR and dynamic light scattering (DLS) techniques. Various interfacial and thermodynamic parameters are determined in the presence of different wt% of IL [Emim][Br]. Information regarding the local microenvironment and size of the aggregates is obtained from fluorescence and DLS, respectively. FT-IR spectral response is used to reveal the interactions taking place within aqueous NaC/NaDC micellar solutions. It is noteworthy to mention that increasing wt% of [Emim][Br] results in an increase in the spontaneity of micelle formation and the hydrophilic IL shows more affinity for NaC as compared to NaDC. Further, the micellar solutions of BS-[Emim][Br] are utilized for studying the aggregation of antidepressants drug promazine hydrochloride (pH). UV-vis spectroscopic investigation reveals interesting outcomes and the results show changes in spectral absorbance of PH drug on the addition of micellar solution (BS-[Emim][Br]). Highest binding affinity and most promising activity are shown for NaC as compared to NaDC.

High power density supercapacitors based on the carbon dioxide activated D-glucose derived carbon electrodes and 1-ethyl-3-methylimidazolium tetrafluoroborate ionic liquid

Science.gov (United States)

Tooming, T.; Thomberg, T.; Kurig, H.; Jänes, A.; Lust, E.

2015-04-01

The electrochemical impedance spectroscopy, cyclic voltammetry, constant current charge/discharge and the constant power discharge methods have been applied to establish the electrochemical characteristics of the electrical double-layer capacitor (EDLC) consisting of the 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF4) ionic liquid and microporous carbon electrodes. Microporous carbon material used for preparation of electrodes (GDAC - glucose derived activated carbon), has been synthesised from D-(+)-glucose by the hydrothermal carbonization method, including subsequent pyrolysis, carbon dioxide activation and surface cleaning step with hydrogen. The Brunauer-Emmett-Teller specific surface area (SBET = 1540 m2 g-1), specific surface area calculated using the non-local density functional theory in conjunction with stable adsorption integral equation using splines (SAIEUS) model SSAIEUS = 1820 m2 g-1, micropore surface area (Smicro = 1535 m2 g-1), total pore volume (Vtot = 0.695 cm3 g-1) and the pore size distribution were obtained from the N2 sorption data. The SBET, Smicro and Vtot values have been correlated with the electrochemical characteristics strongly dependent on the carbon activation conditions applied for EDLCs. Wide region of ideal polarizability (ΔV ≤ 3.2 V), very short charging/discharging time constant (2.7 s), and high specific series capacitance (158 F g-1) have been calculated for the optimized carbon material GDAC-10h (activation of GDAC with CO2 during 10 h) in EMImBF4 demonstrating that this system can be used for completing the EDLC with high energy- and power densities.

Thermophysical properties of ionic liquid {1-butyl-3-methylimidazolium bromide [bmim][Br] in alkoxyalkanols + water} mixtures at different temperatures

International Nuclear Information System (INIS)

Pal, Amalendu; Kumar, Harsh; Kumar, Bhupinder; Sharma, Pooja; Kaur, Kirtanjot

2013-01-01

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 (V φ ) and adiabatic compressibility (K φ,S ) of alkoxyalkanols in aqueous ionic liquid solution were determined at the measured temperatures. The partial molar volume (V φ 0 ) and partial molar adiabatic compressibility (K φ 0 ) of alkoxyalkanols at infinite dilution were evaluated. Transfer volumes (ΔV φ 0 ) and transfer adiabatic compressibility (ΔK φ 0 ) 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 (φ E 0 ) and the Hepler’s constant values, (∂ 2 V φ 0 /∂T 2 ). The results were explained on the basis of competing patterns of interactions of co-solvent and the solute.

Raman Spectroscopic Study of the Vapour Phase of 1-Methylimidazolium Ethanoate, a Protic Ionic Liquid

DEFF Research Database (Denmark)

Berg, Rolf W.; Canongia Lopes, Jose N.; Ferreira, Rui

2010-01-01

The gas phase over the ionic liquid 1-methylimidazolium ethanoate, [Hmim][O2CCH3], was studied by means of Raman spectroscopy. Raman spectra are presented, the species in the gas phase are identified, and their bands are assigned. The results are interpreted using ab initio quantum mechanical...

Reactions of CH-acids with α,β-unsaturated aldehydes in ionic liquids

DEFF Research Database (Denmark)

Kryshtal, G. V.; Zhdankina, G. M.; Astakhova, Irina Kira

2004-01-01

Metal carbonate-catalyzed reactions of CH-acids (diethyl malonate, ethyl acetoacetate, ethyl cyanoacetate, and ethyl 2-acetyl- and 2-ethoxycarbonyl-5,9- dimethyldeca-4,8-dienoates) with α,β-unsaturated aldehydes (acrolein, crotonaldehyde, citral) were studied in an ionic liquid, 1-butyl-3......- methylimidazolium hexafluorophosphate [bmim][PF 6], and in a 1-butyl-3-methylimidazolium bromide ([bmim][Br]) - benzene system. The reactions with acrolein and crotonaldehyde afforded Michael addition products, those with citral resulted in Knoevenagel addition products. Sonication increased the yields...

Studies of Latent Acidity and Neutral Buffered Chloroaluminate Ionic Liquids

National Research Council Canada - National Science Library

Osteryoung, Robert

2000-01-01

Studies on ionic liquids composed of aluminum chloride and 1-ethyl-3-methylimidazolium chloride were carried out, with emphasis on understanding and explaining acidity and latent acidity in "neutral buffered" melts...

Cu(II complexes of an ionic liquid-based Schiff base [1-{2-(2-hydroxy benzylidene amino ethyl}-3-methyl­imidazolium]Pf6: Synthesis, characterization and biological activities

Directory of Open Access Journals (Sweden)

Saha Sanjoy

2015-01-01

Full Text Available Two Cu(II complexes of an ionic liquid based Schiff base 1-{2-(2-hydroxybenzylideneamino ethyl}-3-methylimidazolium hexaflurophosphate, were prepared and characterized by different analytical and spectroscopic methods such as elemental analysis, magnetic susceptibility, UV-Vis, IR, NMR and mass spectroscopy. The Schiff base ligand was found to act as a potential bidentate chelating ligand with N, O donor sites and formed 1:2 metal chelates with Cu(II salts. The synthesized Cu(II complexes were tested for biological activity.

TRANSPORT PROPERTIES FOR 1-ETHYL-3-METHYLIMIDAZOLIUM n-ALKYL SULFATES: POSSIBLE EVIDENCE OF GROTTHUSS MECHANISM

International Nuclear Information System (INIS)

García-Garabal, S.; Vila, J.; Rilo, E.; Domínguez-Pérez, M.; Segade, L.; Tojo, E.; Verdía, P.; Varela, L.M.; Cabeza, O.

2017-01-01

The objective of this work was to study the effect of the temperature and the lengthening of the linear alkyl chain of the anion in the transport physical properties of the pure ionic liquids 1-ethyl-3-methyl imidazolium n-alkyl sulphate (being n = 0, 1, 2, 4, 6 and 8). Density, viscosity and electrical conductivities were measured at atmospheric pressure in a wide temperature range. In the bibliography, data existed for these magnitudes for all ionic liquids studied but none of these had information about the electrical conductivity of 1-ethyl-3-methyl imidazolium n-alkyl sulfate whith n = 0, 4, 6 and 8. The experimental results show clearly 1-ethyl-3-methyl imidazolium hydrogen sulphate cannot be considered part of the 1-ethyl-3-methyl imidazolium n-alkyl sulphate family because of its hydrogen bonding ability. Results of density and viscosity behave as expected. However, in the case of the electrical conductivity due to the lack of alkyl chain in the hydrogen sulfate we expected to get extreme values but in practise, we obtained intermediate values between 1-ethyl-3-methyl imidazolium butyl sulphate and 1-ethyl-3-methyl imidazolium hexyl sulphate. This suggests that a Grotthus mechanism exists as result of a protonic current in addition to ionic conductivity, being Waldeńs plot consistent with this idea.

The physicochemical properties of the low-temperature ionic liquid silver bromide-1-butyl-3-methylimidazolium bromide

Science.gov (United States)

Grishina, E. P.; Ramenskaya, L. M.; Pimenova, A. M.

2009-11-01

The physicochemical properties of the low-temperature ionic liquid based on 1-butyl-3-methylimidazolium bromide (BMImBr) and silver bromide were studied. Differential scanning calorimetry, Fourier transform IR spectroscopy, densimetry, viscometry, and conductometry measurements were performed to determine the dependences of the parameters under study on the concentration of AgBr. It was shown that the temperature and concentration behavior of the physicochemical properties of BMImBr-AgBr melts characterized the interaction between the system components with the formation of complex particles.

Determination of the solubility parameter of ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate by inverse gas chromatography.

Science.gov (United States)

Ma, Xiaohong; Wang, Qiang; Li, Xiaoping; Tang, Jun; Zhang, Zhengfang

2015-11-01

Thermodynamic properties of ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM] BF4) were determined via inverse gas chromatography (IGC). Two groups of solvents with different chemical natures and polarities were used to obtain information about [BMIM] BF4-solvent interactions. The specific retention volume, molar heat of sorption, weight fraction activity coefficient, Flory-Huggins interaction parameter as well as solubility parameter were also determined in a temperature range of 333 - 373 K. The results showed that the selected solvents n-C10 to n-C12, carbon tetrachloride, cyclohexane and toluene were poor solvents for [BMIM] BF4, while dichloromethane, acetone, chloroform, methyl acetate, ethanol and methanol were favorite solvents for [BMIM] BF4. In addition, the solubility parameter of [ BMIM] BF4 was determined as 23.39 (J/cm3)0.5 by the extrapolation at 298 K. The experiment proved that IGC was a simple and accurate method to obtain the thermodynamic properties of ionic liquids. This study could be used as a reference to the application and research of the ionic liquids.

Solubility, density and excess molar volume of binary mixtures of aromatic compounds and common ionic liquids at T=283.15K and atmospheric pressure

OpenAIRE

Emilio J Gonzalez; Patricia Requejo; Filipa Maia; Ángeles Dominguez; Maria Eugénia Macedo

2015-01-01

In this work, the solubility of aromatic compounds (benzene, or toluene, or ethylbenzene, or o-xylene, or m-xylene, or p-xylene) in several ionic liquids (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, or 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, or 1-ethyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide, or 1-propyl-3-methylpyridinium bis(trifluoromethylsulfonyl)imide, or 1-ethyl-3-methylpyridinium ethylsulfate, or 1-hexyl-3-methylimidazolium dicyana...

High-pressure phase behavior of systems with ionic liquids: Part V. The binary system carbon dioxide+1-butyl-3-methylimidazolium tetrafluoroborate

NARCIS (Netherlands)

Kroon, M.C.; Shariati - Sarabi, A.; Costantini, M.; Spronsen, van J.; Witkamp, G.J.; Sheldon, R.A.; Peters, C.J.

2005-01-01

The phase behavior of the binary system consisting of the supercritical fluid carbon dioxide (CO2) and the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) was studied experimentally. A synthetic method was used to measure its phase behavior. Bubble-point pressures of the

Solubilities of some gases in four immidazolium-based ionic liquids

International Nuclear Information System (INIS)

Afzal, Waheed; Liu, Xiangyang; Prausnitz, John M.

2013-01-01

Graphical abstract: Experimental apparatus based on the synthetic-volumetric method for measuring solubilities of gases in liquids. Highlights: • We constructed an apparatus for measuring solubilities of sparingly-soluble gases. • We measured solubilities of five gases in four immidazolium-based ionic liquids. • We calculated Henry’s constants for gases in the ionic liquids studied in this work. -- Abstract: The synthetic-volumetric method is used for rapidly measuring solubilities of sparingly-soluble gases in monoethylene glycol and in four ionic liquids. Known molar quantities of solute and solvent are charged into an equilibrium vessel. Measured quantities at equilibrium include: temperature, pressure, quantities of fluids, and volumes of the gas and liquid phases in the equilibrium vessel. These measurements enable calculation of equilibrium compositions using material balances. No sampling or chemical analyses are required. Solubilities are reported for carbon dioxide, krypton, oxygen, and hydrogen in monoethylene glycol, l-n-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF4], l-n-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6], 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [EMIM][Tf 2 N], or 1-ethyl-3-methylimidazolium acetate [EMIM][AC]. Solubilities were measured over the temperature range (298 to 355) K and for pressures up to about 7 MPa using two different pieces of equipment, both based on the volumetric method: a low-pressure glass apparatus and a high-pressure stainless-steel apparatus. Special emphasis is given to experimental reliability to assure consistent data

Surface polymerization of (3,4-ethylenedioxythiophene) probed by in situ scanning tunneling microscopy on Au(111) in ionic liquids.

Science.gov (United States)

Ahmad, Shahzada; Carstens, Timo; Berger, Rüdiger; Butt, Hans-Jürgen; Endres, Frank

2011-01-01

The electropolymerization of 3,4-ethylenedioxythiophene (EDOT) to poly(3,4-ethylenedioxythiophene) (PEDOT) was investigated in the air and water-stable ionic liquids 1-hexyl-3-methylimidazolium tris(pentafluoroethyl) trifluorophosphate [HMIm]FAP and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) amide [EMIm]TFSA. In situ scanning tunnelling microscopy (STM) results show that the electropolymerization of EDOT in the ionic liquid can be probed on the nanoscale. In contrast to present understanding, it was observed that the EDOT can be oxidised in ionic liquids well below its oxidation potential and the under potential growth of polymer was visualized by in situ STM. These results serve as the first study to confirm the under potential growth of conducting polymers in ionic liquids. Furthermore, ex situ microscopy measurements were performed. Quite a high current of 670 nA was observed on the nanoscale by conductive scanning force microscopy (CSFM).

Biodegradation of imidazolium ionic liquids by activated sludge microorganisms.

Science.gov (United States)

Liwarska-Bizukojc, Ewa; Maton, Cedric; Stevens, Christian V

2015-11-01

Biological properties of ionic liquids (ILs) have been usually tested with the help of standard biodegradation or ecotoxicity tests. So far, several articles on the identification of intermediate metabolites of microbiological decay of ILs have been published. Simultaneously, the number of novel ILs with unrecognized characteristics regarding biodegradability and effect on organisms and environment is still increasing. In this work, seven imidazolium ionic liquids of different chemical structure were studied. Three of them are 1-alkyl-3-methyl-imidazolium bromides, while the other four are tetra- or completely substituted imidazolium iodides. This study focused on the identification of intermediate metabolites of the aforementioned ionic liquids subjected to biodegradation in a laboratory activated sludge system. Both fully substituted ionic liquids and 1-ethyl-3-methyl-imidazolium bromide were barely biodegradable. In the case of two of them, no biotransformation products were detected. The elongation of the alkyl side chain made the IL more susceptible for microbiological decomposition. 1-Decyl-3-methyl-imidazolium bromide was biotransformed most easily. Its primary biodegradation up to 100 % could be achieved. Nevertheless, the cleavage of the imidazolium ring has not been observed.

Selection of ionic liquids as entrainers for separation of (water + ethanol)

Energy Technology Data Exchange (ETDEWEB)

Ge Yun [College of Chemical Engineering and Material Science, Zhejiang University of Technology, Hangzhou 310014 (China); Zhang Lianzhong [College of Chemical Engineering and Material Science, Zhejiang University of Technology, Hangzhou 310014 (China)], E-mail: zhanglz@zjut.edu.cn; Yuan Xingcai; Geng Wei; Ji Jianbing [College of Chemical Engineering and Material Science, Zhejiang University of Technology, Hangzhou 310014 (China)

2008-08-15

For selection of ionic liquids (ILs) which can be potentially used as entrainers for separation of the azeotropic mixture of (water + ethanol) by extractive distillation, (vapor + liquid) equilibrium was measured for the ternary systems of (water + ethanol + an IL) using a previously proposed ebulliometer. The experimental measurement was performed at p = 100 kPa and in a way of continuous synthesis, in which analysis of liquid phase composition was avoided. While the mole fraction of ethanol calculated on IL-free basis, x{sub 2}{sup '}, was kept almost unchanged at 0.95, isobaric T, x, y data were measured at different IL mass fractions. Activity coefficients, as well as relative volatilities, of the volatile components were obtained from the experimental data without the need of a thermodynamic model of the liquid phase. There were eight ILs in our investigation: 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF{sub 4}]), 1-ethyl-3-methylimidazolium tetrafluoroborate ([emim][BF{sub 4}]), 1-butyl-3-methylimidazolium dicyanamide ([bmim][N(CN){sub 2}]), 1-ethyl-3-methylimidazolium dicyanamide ([emim][N(CN){sub 2}]), 1-butyl-3-methylimidazolium chloride ([bmim][Cl]), 1-ethyl-3-methylimidazolium chloride ([emim][Cl]), 1-butyl-3-methylimidazolium acetate ([bmim][OAc]), and 1-ethyl-3-methylimidazolium acetate ([emim][OAc]). The effect of the ILs on the relative volatility of the volatile components was depicted separately by their effect on the activity coefficients. The results indicated that, among the eight ILs studied, [emim][Cl] has the largest effect on enhancement of the relative volatility. Another IL, [emim][OAc], has also significant effect. Considering the relatively low viscosity and melting point of [emim][OAc], this IL might be favorable candidate as entrainer for potential industrial application.

Isobutane as a probe of the structure of 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquids

International Nuclear Information System (INIS)

Pison, Laure; Bernales, Varinia; Fuentealba, Patricio; Padua, Agilio A.H.

2015-01-01

Highlights: • The solubility of isobutane was determined in [C n C 1 Im][NTf 2 ] (n = 2, 4, 6, 8 and 10). • Iso-C 4 H 10 solubility decreases with T and increases with n to reach x = 0.1 (n = 10, T = 303 K). • Isobutane is, on average, 1.6 times less soluble than n-butane in this family of ionic liquids. • Solubility increase with n is due to a more negative enthalpy of dissolution (n ⩾ 6). - Abstract: An experimental study of the solubility and of the thermodynamic properties of solvation, between temperatures (303 and 343) K and at pressures close to atmospheric, of 2-methylpropane (isobutane) in several ionic liquids based on the bis(trifluoromethylsulfonyl)imide anion and on 1-alkyl-3-methylimidazolium cations, [C n C 1 Im][NTf 2 ], with alkyl side-chains varying from two to ten carbon atoms is presented. The isobutane solubility increases with increasing size of the alkyl side-chain of the cation in the ionic liquid and decreases with increasing temperature (as typical of an exothermal dissolution process). The mole fraction solubility of isobutane varies from 0.904 · 10 −2 in [C 2 C 1 Im][NTf 2 ] at T = 343 K to 1.002 · 10 −1 in [C 10 C 1 Im][NTf 2 ] at T = 303 K. The values measured in this work are compared to the behaviour of n-butane in the same ionic liquids published in a previous study (Costa Gomes et al., 2012). Isobutane was found to be significantly less soluble than n-butane in all the ionic liquids. The differences found are interpreted in relation to the molecular structures obtained by molecular dynamics simulations for the solutions of n-butane and isobutane in the studied [C n C 1 Im][NTf 2 ] ionic liquids

Crystal structure of the tetragonal polymorph of bis(1-ethyl-3-methylimidazolium tetrabromidocadmate

Directory of Open Access Journals (Sweden)

Tamara Đorđević

2016-07-01

Full Text Available Both unique Cd atoms in the tetragonal polymorph of bis(1-ethyl-3-methylimidazolium tetrabromidocadmate, (C6H11N22[CdBr4], occupy special positions (site symmetry -4. The crystal structure consists of isolated tetrahedral [CdBr4]2− anions which are surrounded by 1-ethyl-3-methylimidazolium cations. The methyl and ethyl side chains of the cations show positional disorder in a 0.590 (11:0.410 (11 ratio. In the crystal, (C6H11N2+ cations display three weak C—H...Br hydrogen-bond interactions through the imidazolium ring H atoms with the Br− ligands of the surrounding complex anions. The alkyl groups of the side chains are not involved in hydrogen bonding.

Ionic liquid 1-hexyl-3-methylimidazolium hexafluorophosphate, an efficient solvent for extraction of acetone from aqueous solutions

International Nuclear Information System (INIS)

Saien, Javad; Badieh, Marjan Mohammadi Sarab; Norouzi, Mahdi; Salehzadeh, Sadegh

2015-01-01

Highlights: • The use of HMIMPF_6 as a green ionic was feasible in the extraction of acetone from water. • The binodal curves were determined by cloud point measurement method. • High level separation factor of acetone between the ionic liquid and water were achieved. • The thermodynamic properties of HMIMPF_6 were obtained by the Density Functional Theory calculations. • The NRTL and UNIQUAC models were applied satisfactorily to correlate the equilibrium data. - Abstract: (Liquid + liquid) equilibrium (LLE) of the chemical system of {water + acetone + 1-Hexyl-3-methylimidazolium hexafluorophosphate (HMIMPF_6) ionic liquid} was studied at different temperatures of (293.2, 298.2 and 303.2) K and under atmospheric pressure of 81.5 kPa. The results show that HMIMPF_6 provides the acetone distribution coefficient and separation factor values within (0.8813 to 1.2351) and (3.0 to 54.4), respectively; indicating the high capability of the ionic liquid for extraction of acetone from aqueous solutions. In most cases, acetone solubility in the ionic liquid is higher than in water, especially at higher solute concentrations. Meanwhile, higher separation factor is relevant to the lower temperature due to lower (water + ionic liquid) miscibility. The consistency of tie line data, at each temperature, was examined with Othmer–Tobias correlation. The values were nicely reproduced with the well-known NRTL and UNIQUAC models. Accordingly, the required thermodynamic properties of HMIMPF_6 were obtained by the Density Functional Theory (DFT) calculations, carried out at the M06/6-311++G"∗"∗ level of theory. The root mean square deviations (RMSD) between experimental and model concentration values were 0.0192 and 0.0255, respectively; indicating close agreement of the both models.

Isothermogravimetric determination of the enthalpies of vaporization of 1-alkyl-3-methylimidazolium ionic liquids.

Science.gov (United States)

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

2008-08-21

Vaporization enthalpies for two series of ionic liquids (ILs) composed of 1- n-alkyl-3-methylimidazolium cations, [Imm1+] (m=2, 3, 4, 6, 8, or 10), paired with either the bis(trifluoromethanesulfonyl)amide, [Tf2N-], or the bis(perfluoroethylsulfonyl)amide anion, [beti-], were determined using a simple, convenient, and highly reproducible thermogravimetric approach, and from these values, Hildebrand solubility parameters were estimated. Our results reveal two interesting and unanticipated outcomes: (i) methylation at the C2 position of [Imm1+] affords a significantly higher vaporization enthalpy; (ii) in all cases, the [beti-] anion served to lower the enthalpy of vaporization relative to [Tf2N-]. The widespread availability of the apparatus required for these measurements coupled with the ease of automation suggests the broad potential of this methodology for determining this critical parameter in a multitude of ILs.

A coarse-grained polarizable force field for the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate

Science.gov (United States)

Zeman, Johannes; Uhlig, Frank; Smiatek, Jens; Holm, Christian

2017-12-01

We present a coarse-grained polarizable molecular dynamics force field for the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIm][PF6]). For the treatment of electronic polarizability, we employ the Drude model. Our results show that the new explicitly polarizable force field reproduces important static and dynamic properties such as mass density, enthalpy of vaporization, diffusion coefficients, or electrical conductivity in the relevant temperature range. In situations where an explicit treatment of electronic polarizability might be crucial, we expect the force field to be an improvement over non-polarizable models, while still profiting from the reduction of computational cost due to the coarse-grained representation.

Hydrophobic ionic liquids based on the 1-butyl-3-methylimidazolium cation for lithium/seawater batteries

Science.gov (United States)

Zhang, Yancheng; Urquidi-Macdonald, Mirna

Two hydrophobic ionic liquids (room temperature molten salts) based on 1-butyl-3-methylimidazolium cation (BMI +), BMI +PF 6- and BMI +Tf 2N -, were used in developing a highly efficient lithium anode system for lithium/seawater batteries. The lithium anode system was composed of lithium metal/ionic liquid/Celgard membrane. Both BMI +PF 6-and BMI +Tf 2N - maintained high apparent anodic efficiency (up to 100%) under potentiostatic polarization (at +0.5 V versus open-circuit potential (OCP)) in a 3% NaCl solution. Eventually, traces of water contaminated the ionic liquid and a bilayer film (LiH and LiOH) on the lithium surface was formed, decreasing the rate of lithium anodic reaction and hence the discharge current density. BMI +Tf 2N - prevented traces of water from reaching the lithium metal surface longer than BMI +PF 6- (60 h versus 7 h). However, BMI +PF 6- was better than BMI +Tf 2N - in keeping a constant current density (˜0.2 mA cm -2) before the traces of water contaminated the lithium surface due to the non-reactivity of BMI +PF 6- with the lithium metal that kept the bare lithium surface. During the discharge process, BMI +PF 6- and BMI +Tf 2N - acted as ion transport media of Li +, Cl -, OH - and H 2O, but did not react with them because of the excellent chemical stability, high conductivity, and high hydrophobicity of these two ionic liquids. Both BMI +PF 6- and BMI +Tf 2N - gels were tentative approaches used to delay the traces of water coming in contact with the lithium surface.

Binary and ternary LLE data of the system (ethylbenzene + styrene + 1-ethyl-3-methylimidazolium thiocyanate) and binary VLE data of the system (styrene + 1-ethyl-3-methylimidazolium thiocyanate)

International Nuclear Information System (INIS)

Jongmans, Mark T.G.; Schuur, Boelo; Haan, André B. de

2012-01-01

Highlights: ► LLE data have been measured for the system {ethylbenzene + styrene + [EMIM][SCN]}. ► VLE was determined for the system {styrene + [EMIM][SCN]} at vacuum conditions. ► All experimental data were correlated well with the NRTL model. ► [EMIM][SCN] has a much larger selectivity than the benchmark solvent sulfolane. - Abstract: The distillation of close boiling mixtures may be improved by adding a proper affinity solvent, and thereby creating an extractive distillation process. An example of a close boiling mixture that may be separated by extractive distillation is the mixture ethylbenzene/styrene. The ionic liquid 1-ethyl-3-methylimidazolium thiocyanate ([EMIM][SCN]) is a promising solvent to separate ethylbenzene and styrene by extractive distillation. In this study, (vapour + liquid) equilibrium data have been measured for the binary system (styrene + [EMIM][SCN]) over the pressure range of (3 to 20) kPa and binary and ternary (liquid + liquid) equilibrium data of the system (ethylbenzene + styrene + [EMIM][SCN]) at temperatures (313.2, 333.2 and 353.2) K. Due to the low solubility of ethylbenzene in [EMIM][SCN], it was not possible to measure accurately VLE data of the binary system (ethylbenzene + [EMIM][SCN]) and of the ternary system (ethylbenzene + styrene + [EMIM][SCN]) using the ebulliometer. Because previous work showed that the LLE selectivity is a good measure for the selectivity in VLE, we determined the selectivity with LLE. The selectivity of [EMIM][SCN] to styrene in LLE measurements ranges from 2.1 at high styrene raffinate purity to 2.6 at high ethylbenzene raffinate purity. The NRTL model can properly describe the experimental results. The rRMSD in temperature, pressure and mole fraction for the binary VLE data are respectively (0.1, 0.12 and 0.13)%. The rRMSD is only 0.7% in mole fraction for the LLE data.

Generation of a platform strain for ionic liquid tolerance using adaptive laboratory evolution

DEFF Research Database (Denmark)

Mohamed, Elsayed T.; Wang, Shizeng; Lennen, Rebecca M.

2017-01-01

There is a need to replace petroleum-derived with sustainable feedstocks for chemical production. Certain biomass feedstocks can meet this need as abundant, diverse, and renewable resources. Specific ionic liquids (ILs) can play a role in this process as promising candidates for chemical...... of two different ionic liquids, 1-ethyl-3-methylimidazolium acetate ([C2C1Im][OAc]) and 1-butyl-3-methylimidazolium chloride ([C4C1Im]Cl). For multiple parallel replicate populations of E. coli, cells were repeatedly passed to select for improved fitness over the course of approximately 40 days. Clonal...

Solubility of gases in 1-alkyl-3methylimidazolium alkyl sulfate ionic liquids: Experimental determination and modeling

International Nuclear Information System (INIS)

Bermejo, María Dolores; Fieback, Tobias M.; Martín, Ángel

2013-01-01

Highlights: ► The solubility of CO 2 , CH 4 and C 2 H 6 in [emim][EtSO 4 ] is measured with a magnetic suspension balance. ► New data and literature results have been modeled with a Group Contribution equation of state. ► A specific group definition is required to model data of ionic liquids with a [MeSO 4 ] anion. ► Deviations between model and experiments are lower than 10% in most cases. ► Deviations of 34% are observed in the case of the solubility of ethane in the ionic liquid. -- Abstract: The solubility of different gases (carbon dioxide, methane, ethane, carbon monoxide and hydrogen) in ionic liquids with an alkyl sulfate anion has been modeled with the Group Contribution equation of state developed by Skjold-Jørgensen. New gas solubility measurements have been carried out with a high pressure magnetic suspension balance in order to cover pressure and temperature ranges not considered in previous studies and to obtain more experimental information for the correlation of parameters of the equation of state. New solubility measurements include the solubility of carbon dioxide in 1-ethyl 3-methyl imidazolium ethyl sulfate [emim][EtSO 4 ] at temperatures of 298 K and 348 K and pressures ranging from 0.3 MPa to 6.5 MPa, the solubility of methane in [emim][EtSO 4 ] at a temperature of 293 K and pressures ranging from 0.2 MPa to 10.2 MPa, and the solubility of ethane in [emim][EtSO 4 ] at temperatures of 323 K and 350 K and pressures ranging from 0.2 MPa to 4 MPa. Results show that the Group Contribution equation of state can be used to describe the solubility of gases in alkyl sulfate ionic liquids as well as infinite dilution coefficients of alkanes in the ionic liquids, with average deviations between experiments and calculations ranging from 1% to 10% in the case of mixtures with CO 2 , CO, CH 4 and H 2 with the alkyl sulfate ionic liquids to up to 34% in the case of the solubility of ethane in [emim][EtSO 4

Prediction of the vapor pressure and vaporization enthalpy of 1-n-alkyl-3-methylimidazolium-bis-(trifluoromethanesulfonyl) amide ionic liquids.

Science.gov (United States)

Diedenhofen, Michael; Klamt, Andreas; Marsh, Kenneth; Schäfer, Ansgar

2007-09-07

The vapor pressures and vaporization enthalpies of a series of 1-n-alkyl-3-methylimidazolium-bis-(trifluoromethanesulfonyl) amide ionic liquids have been predicted with two different approaches using the COSMO-RS method and quantum chemical gas phase calculations. While the calculated enthalpies are in good agreement with the experimental data, COSMO-RS seems to underestimate the vapor pressures by roughly 0.5-4 log units dependent on the IL and approach used.

Ionic Liquids as a New Platform for Fiber Brittleness Removal

Directory of Open Access Journals (Sweden)

Zhili Zhang

2015-08-01

Full Text Available In the present study, three ionic liquids, 1-butyl-3-methylimidazolium chloride ([BMIM]Cl, 1-allyl-3-methylimidazolium ([AMIM]Cl, and 1-ethyl-3-methylimidazolium chloride dimethyphosphate ([EMIM]DMP, were used to eliminate the brittleness of recycled fibers. The results showed that the pretreatments with ionic liquids were able to modify and improve the properties of recycled fibers even at high moisture contents. [EMIM]DMP gave better performance compared to [BMIM]Cl and [AMIM]Cl, which can tolerate higher moisture contents. The optimal conditions of EMIM]DMP pretreatment were moisture content of 65%, [EMIM]DMP dosage of 20 wt-%, 80 °C, and 60 min, for which a higher brittleness removal was obtained. The tensile index, bursting index, and tearing index of handsheets were increased by 32.4%, 57.0%, and 46.5%, respectively. Fiber quality was improved as demonstrated by fiber length, lowered fines content, and increased swellability. Such results imply that ionic liquids pretreatment can promote the swelling of recycled fibers and remove their brittleness.

Carbon Dioxide Separation with Supported Ionic Liquid Membranes

Energy Technology Data Exchange (ETDEWEB)

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

2007-04-01

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

Soft ionization of thermally evaporated hypergolic ionic liquid aerosols

Energy Technology Data Exchange (ETDEWEB)

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

2011-07-19

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

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

Science.gov (United States)

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

2018-02-01

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

Application of the PFV EoS correlation to excess molar volumes of (1-ethyl-3-methylimidazolium ethylsulfate + alkanols) at different temperatures

International Nuclear Information System (INIS)

Deenadayalu, N.; Sen, S.; Sibiya, P.N.

2009-01-01

The experimental densities for the binary systems of an ionic liquid and an alkanol {1-ethyl-3-methylimidazolium ethylsulfate [EMIM] + [EtSO 4 ] - + methanol or 1-propanol or 2-propanol} were determined at T = (298.15, 303.15, and 313.15) K. The excess molar volumes for the above systems were then calculated from the experimental density values for each temperature. The Redlich-Kister smoothing polynomial was used to fit the experimental results and the partial molar volumes were determined from the Redlich-Kister coefficients. For all the systems studied, the excess molar volume results were negative over the entire composition range for all the temperatures. The excess molar volumes were correlated with the pentic four parameter virial (PFV) equation of state (EoS) model

Viscosity of binary mixtures of 1-ethyl-3-methylimidazolium tetrafluoroborate ionic liquid with four organic solvents

International Nuclear Information System (INIS)

Ciocirlan, Oana; Croitoru, Oana; Iulian, Olga

2016-01-01

Highlights: • Viscosities of four binary mixtures of [Emim][BF4] with organic solvents. • Viscosity models based on Eyring’s theory. • Excess functions calculated. • Data for binaries new in the literature, except for system with DMSO. - Abstract: This paper reports experimental values of dynamic viscosity for four binary systems of 1-ethyl-3-methylimidazolium tetrafluoroborate, [Emim][BF4], with dimethyl sulfoxide (DMSO), acetonitrile (ACN), ethylene glycol (EG) and 1,4-dioxane over the temperature ranges from 293.15 K to 353.15 K at p = 0.1 MPa. All binary mixtures were completely miscible over the entire range of mole fraction, except the system with 1,4-dioxane. The viscosity results have been correlated by the one parameter Grunberg–Nissan and Fang and He equations and the two-parameter McAllister, Eyring-UNIQUAC, Eyring-NRTL and Eyring-Wilson models and the results were compared. Additionally, the viscosity deviations, Δη, and the excess Gibbs energy of activation for viscous flow, G"∗"E, were calculated and fitted to the Redlich–Kister equation. The results show that all Δη values are negative over the whole composition range and the G"∗"E values are positive, except for the system with EG. The results of the excess functions are discussed in terms of molecular interactions.

Supra-molecular inclusion complexation of ionic liquid 1-butyl-3-methylimidazolium octylsulphate with α- and β-cyclodextrins

Science.gov (United States)

Banjare, Manoj Kumar; Behera, Kamalakanta; Satnami, Manmohan L.; Pandey, Siddharth; Ghosh, Kallol K.

2017-12-01

Host-guest complexation between ionic liquid (IL) 1-butyl-3-methylimidazolium octylsulphate [Bmim][OS] and cyclodextrins (α- and β- CDs) have been studied. Surface tension, conductivity measurements revealed the formation of 1:1 (M) stoichiometry for inclusion complexes (ICs) and further confirmed by UV-Visible and FT-IR results. The nature of the complexes has been established using interfacial and thermodynamic parameters. The aggregation number, Stern-Volmer constants, association constants were obtained from fluorescence quenching and Benesi-Hildebrand methods. The critical micelle concentration (cmc) and association constants of [Bmim][OS] are higher for β-CD as compared to α-CD. FT-IR spectra indicated that CDs and [Bmim][OS] could from ICs with stoichiometry 1:1 (M).

Study on the enthalpy of solution and enthalpy of dilution for the ionic liquid [C3mim][Val] (1-propyl-3-methylimidazolium valine)

International Nuclear Information System (INIS)

Guan Wei; Li Long; Ma Xiaoxue; Tong Jing; Fang Dawei; Yang Jiazhen

2012-01-01

Graphical abstract: The thermodynamic cycle for estimation of the hydration enthalpy of ionic liquid [C 3 mim][Val]. Highlights: ► A new amino acid ionic liquid [C 3 mim][Val] was prepared. ► The molar enthalpies of solution of the ionic liquid. ► The hydration enthalpy of the cation [C 3 mim] + was estimated. ► The molar enthalpies of dilution, of aqueous [C 3 mim][Val] were measured. - Abstract: A new amino acid ionic liquid (AAIL) [C 3 mim][Val] (1-propyl-3-methylimidazolium valine) was prepared by the neutralization method. Using the solution-reaction isoperibol calorimeter, molar solution enthalpies of the ionic liquid [C 3 mim][Val] with known amounts of water and with different concentrations in molality were measured at T = 298.15 K. In terms of standard addition method (SAM) and Archer’s method, the standard molar enthalpy of solution for [C 3 mim][Val] without water, Δ s H m ∘ = (−55.7 ± 0.4) kJ · mol −1 , was obtained. The hydration enthalpy of the cation [C 3 mim] + , ΔH + ([C 3 mim] + ) = −226 kJ · mol −1 , was estimated in terms of Glasser’s theory. Using the RD496-III heat conduction microcalorimeter, the molar enthalpies of dilution, Δ D H m (m i → m f ), of aqueous [C 3 mim][Val] with various values of molality were measured. The values of Δ D H m (m i → m f ) were fitted to Pitzer’s ion-interaction model and the values of apparent relative molar enthalpy, φ L, calculated using Pitzer’s ion-interaction model.

Soft Ionization of Thermally Evaporated Hypergolic Ionic Liquid Aerosols

Energy Technology Data Exchange (ETDEWEB)

Koh, Christine J. [Univ. of California, Berkeley, CA (United States); Liu, Chen-Lin [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Harmon, Christopher W. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Strasser, Daniel [Univ. of California, Berkeley, CA (United States); Golan, Amir [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kostko, Oleg [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Chambreau, Steven D. [Edwards Air Force Base, ERC Inc., CA (United States); Vaghjiani, Ghanshyam L. [Air Force Research Laboratory, Edwards Air Force Base, CA (United States); Leone, Stephen R. [Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2011-04-20

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

Critical properties and acentric factors of ionic liquids

International Nuclear Information System (INIS)

Shariati, Alireza; Ashrafmansouri, Seyedeh-Soghra; Osbuei, Maryam Haji; Hooshdaran, Bahar

2013-01-01

Since most ionic liquids (ILs) decompose before reaching their critical state, the experimental measurement of their critical properties are not possible. In this study, the critical temperatures, critical pressures and acentric factors of ten commonly investigated ILs were determined by making an optimum fit of the calculated vapor-liquid equilibrium data of binary mixtures of CO 2 +IL to the experimental values found in literature. For this purpose, the Peng-Robinson equation of state (PR EoS) and the differential evolution optimization method were used. The ILs considered were 1-ethyl-3-methylimidazolium hexafluorophosphate ([emim][PF 6 ]), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([emim][Tf 2 N]), 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF 4 ]), 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF 6 ]), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([bmim][Tf 2 N]), 1-hexyl-3-methylimidazolium tetrafluoroborate ([hmim][BF 4 ]), 1-hexyl-3-methylimidazolium hexafluorophosphate ([hmim][PF 6 ]), 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([hmim][Tf 2 N]), 1-octyl-3-methylimidazolium tetrafluoroborate ([omim][BF 4 ]) and 1-octyl-3-methylimidazolium hexafluorophosphate ([omim][PF 6 ]). To evaluate the ability of the determined parameters in predicting the phase behavior of systems other than the systems that were used for parameter optimization, both sets of parameters obtained in this work and that of Valderrama et al. were used to predict bubble-point pressures of CHF 3 +[bmim][PF 6 ] (by using the PR EoS and the Soave-Redlich-Kwong equation of state. The bubble-point pressures of CO 2 +IL systems optimized in this study by the PR EoS were also determined using the Soave-Redlich-Kwong equation of state (SRK EoS). In addition, liquid densities of pure ILs were predicted using a generalized correlation proposed by Valderrama and Abu-Shark. In all cases, the various predicted properties of

The acute toxic effects of 1-alkyl-3-methylimidazolium nitrate ionic liquids on Chlorella vulgaris and Daphnia magna.

Science.gov (United States)

Zhang, Cheng; Zhang, Shuai; Zhu, Lusheng; Wang, Jinhua; Wang, Jun; Zhou, Tongtong

2017-10-01

Given their increasingly widespread application, the toxic effects of ionic liquids (ILs) have become the subject of significant attention in recent years. Therefore, the present study assessed the acute toxic effects of 1-alkyl-3-methylimidazolium nitrate ([C n mim]NO 3 (n = 2, 4, 6, 8, 10, 12)) on Chlorella vulgaris and Daphnia magna. The sensitivity of the tested organism Daphnia magna and the investigated IL concentrations in water using high-performance liquid chromatography (HPLC) were also evaluated to demonstrate the reliability of the present study. The results illustrated that Daphnia magna is indeed sensitive to the reference toxicant and the investigated ILs were stable in the aquatic environment. The 50% effect concentration (EC 50 ) was used to represent the acute toxic effects on Chlorella vulgaris and Daphnia magna. With the increasing alkyl-chain lengths, the toxicity of the investigated ILs increased in both the test organisms. Accordingly, the alkyl-chain lengths can cause significantly toxic effects on aquatic organisms, and Daphnia magna are much more sensitive than Chlorella vulgaris to the imidazolium-based ILs used in the present study. Furthermore, the present study provides more information on the acute toxic effects of 1-alkyl-3-methylimidazolium nitrate. Copyright © 2017 Elsevier Ltd. All rights reserved.

Studies on properties of ionic liquids 1-alkyl-3-methylimidazolium lactate at temperatures from (288.15 to 333.15) K

International Nuclear Information System (INIS)

Hong, Mei; Sun, Ao; Yang, Qi; Guan, Wei; Tong, Jing; Yang, Jia-Zhen

2013-01-01

Highlights: • Two ILs [C 2 mim][Lact] and [C 5 mim][Lact] were prepared. • The density, surface tension and refractive index for two ILs were measured in terms of SAT. • Using Kabo’s and Rebelo’s method, the molar enthalpy of evaporation for two ILs was estimated. • The surface tension was estimated using the parachor and the refractive index. -- Abstract: Two chiral ionic liquids based on lactic acid (LAILs), 1-ethyl-3-methylimidazolium lactate ([C 2 mim][Lact]) and 1-pentyl-3-methylimidazolium lactate ([C 5 mim][Lact]), have been prepared by the neutralization method and characterized by 1 H NMR and DSC. Their density, surface tension and refractive index were measured at T {(288.15 to 333.15) ± 0.05} K. Since the LAILs can form strong hydrogen bonds with water, small amounts of water are difficult to remove by conventional methods. In order to eliminate the effect of the impurity as water, the standard addition method (SAM) was applied to these measurements. The molar volume of [C n mim][Lact] (n = 2, 5), the thermal expansion coefficient, α, the surface excess entropy, S a , the surface excess energy E a , parachor, P, and molar refraction, R m , were obtained. According to the methods of both Kabo and Rebelo, the molar enthalpy of evapouration of the LAILs was estimated using experimental values for the surface tension and molar volume. At the same time, the surface tension of the LAILs may be estimated using the data of the parachor and refractive index. The estimated values of the surface tension correlate quite well with the corresponding experimental values

Accelerating rate calorimetry studies of the reactions between ionic liquids and charged lithium ion battery electrode materials

International Nuclear Information System (INIS)

Wang, Yadong; Zaghib, K.; Guerfi, A.; Bazito, Fernanda F.C.; Torresi, Roberto M.; Dahn, J.R.

2007-01-01

Using accelerating rate calorimetry (ARC), the reactivity between six ionic liquids (with and without added LiPF 6 ) and charged electrode materials is compared to the reactivity of standard carbonate-based solvents and electrolytes with the same electrode materials. The charged electrode materials used were Li 1 Si, Li 7 Ti 4 O 12 and Li 0.45 CoO 2 . The experiments showed that not all ionic liquids are safer than conventional electrolytes/solvents. Of the six ionic liquids tested, 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMI-FSI) shows the worst safety properties, and is much worse than conventional electrolyte. 1-Ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMI-TFSI) and 1-propyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide (Py13-FSI) show similar reactivity to carbonate-based electrolyte. The three ionic liquids 1-butyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonyl)imide (BMMI-TFSI), 1-butyl-1-methylpiperidinium bis(trifluoromethanesulfonyl)imide (Pp14-TFSI) and N-trimethyl-N-butylammonium bis(trifluoromethanesulfonyl)imide (TMBA-TFSI) show similar reactivity and are much safer than the conventional carbonate-based electrolyte. A comparison of the reactivity of ionic liquids with common anions and cations shows that ionic liquids with TFSI - are safer than those with FSI - , and liquids with EMI + are worse than those with BMMI + , Py13 + , Pp14 + and TMBA +

STRUCTURAL CHANGES EVIDENCED BY FTIR SPECTROSCOPY IN CELLULOSE MATERIALS AFTER PRE-TREATMENT WITH IONIC LIQUID AND ENZYMATIC HYDROLYSIS

Directory of Open Access Journals (Sweden)

Iuliana Spiridon

2011-02-01

Full Text Available Attempts were made to enhance the hydrolysis of Asclepias syriaca (As seed floss and poplar seed floss (PSF by cellulase after pre-treatment with ionic liquids. Two ionic liquids, namely 1-butyl-3-methylimidazolium chloride [BMIM]Cl and 1-ethyl-3-methylimidazolium tetrachloroaluminate [EMIM]Cl-AlCl3, were used. In comparison with conventional cellulose pretreatment processes, the ionic liquids were used under a milder condition corresponding to the optimum activity of cellulase. Hydrolysis kinetics of the IL-treated cellulose materials was significantly enhanced. The initial hydrolysis rates for IL-treated cellulose materials were greater than those of non-treated ones. The structural modifications of hydrolyzed cellulose materials were analyzed using FTIR spectroscopy.

Simulating structure and dynamics in small droplets of 1-ethyl-3-methylimidazolium acetate

Science.gov (United States)

Brehm, Martin; Sebastiani, Daniel

2018-05-01

To investigate the structure and dynamics of small ionic liquid droplets in gas phase, we performed a DFT-based ab initio molecular dynamics study of several 1-ethyl-3-methylimidazolium acetate clusters in vacuum as well as a bulk phase simulation. We introduce an unbiased criterion for average droplet diameter and density. By extrapolation of the droplet densities, we predict the experimental bulk phase density with a deviation of only a few percent. The hydrogen bond geometry between cations and anions is very similar in droplets and bulk, but the hydrogen bond dynamics is significantly slower in the droplets, becoming slower with increasing system size, with hydrogen bond lifetimes up to 2000 ps. From a normal mode analysis of the trajectories, we identify the modes of the ring proton C-H stretching, which are strongly affected by hydrogen bonding. From analyzing these, we find that the hydrogen bond becomes weaker with increasing system size. The cations possess an increased concentration inside the clusters, whereas the anions show an excess concentration on the outside. Almost all anions point towards the droplet center with their carboxylic groups. Ring stacking is found to be a very important structural motif in the droplets (as in the bulk), but side chain interactions are only of minor importance. By using Voronoi tessellation, we define the exposed droplet surface and find that it consists mainly of hydrogen atoms from the cation's and anion's methyl and ethyl groups. Polar atoms are rarely found on the surface, such that the droplets appear completely hydrophobic on the outside.

Scaling-Up Ionic Liquid-Based Technologies: How Much Do We Care About Their Toxicity? Prima Facie Information on 1-Ethyl-3-Methylimidazolium Acetate.

Science.gov (United States)

Ostadjoo, Shaghayegh; Berton, Paula; Shamshina, Julia L; Rogers, Robin D

2018-02-01

The potential of the ionic liquid (IL) 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]) to dissolve a variety of biopolymers such as cellulose and chitin, makes it an attractive candidate for scaled-up industrial utilization. In fact, the first steps towards its use at industrial scale have been taken. This increases the urgency to fill the knowledge gaps in its toxicity and environmental impact in order to predict and control its environmental fate. In this mini-review, we discuss the available literature surrounding this key IL. The literature (through the analysis of toxicity of the anion and the cation separately) suggests that [C2mim][OAc] is a relatively safe choice for industrial applications. However, because the IL should be considered as a compound, with unique properties arising from the interactions between the ions, comprehensive toxicity information for this particular IL is still required. To decide, prima facie, if this IL is toxic or not, evaluation of its influence on human health and ecotoxicity is needed prior to its large scale utilization. We chose in this mini-review to focus on toxicity surrounding this IL and evaluate what is known and what is not. Here with all the information in hand, we hope that the urgent need for [C2mim][OAc] toxicological assessment before it can be used in numerous technologies is highlighted. In the near future, we expect that the assessment of toxicity and environmental fate and impact can be integrated directly into any research into the industrial utilization of this IL and any others contemplated for industrial application. © The Author 2017. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

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

Science.gov (United States)

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

2017-07-01

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

Critical properties and acentric factors of ionic liquids

Energy Technology Data Exchange (ETDEWEB)

Shariati, Alireza; Ashrafmansouri, Seyedeh-Soghra; Osbuei, Maryam Haji; Hooshdaran, Bahar [Shiraz University, Shiraz (Iran, Islamic Republic of)

2013-01-15

Since most ionic liquids (ILs) decompose before reaching their critical state, the experimental measurement of their critical properties are not possible. In this study, the critical temperatures, critical pressures and acentric factors of ten commonly investigated ILs were determined by making an optimum fit of the calculated vapor-liquid equilibrium data of binary mixtures of CO{sub 2}+IL to the experimental values found in literature. For this purpose, the Peng-Robinson equation of state (PR EoS) and the differential evolution optimization method were used. The ILs considered were 1-ethyl-3-methylimidazolium hexafluorophosphate ([emim][PF{sub 6}]), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([emim][Tf{sub 2}N]), 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF{sub 4}]), 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF{sub 6}]), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([bmim][Tf{sub 2}N]), 1-hexyl-3-methylimidazolium tetrafluoroborate ([hmim][BF{sub 4}]), 1-hexyl-3-methylimidazolium hexafluorophosphate ([hmim][PF{sub 6}]), 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([hmim][Tf{sub 2}N]), 1-octyl-3-methylimidazolium tetrafluoroborate ([omim][BF{sub 4}]) and 1-octyl-3-methylimidazolium hexafluorophosphate ([omim][PF{sub 6}]). To evaluate the ability of the determined parameters in predicting the phase behavior of systems other than the systems that were used for parameter optimization, both sets of parameters obtained in this work and that of Valderrama et al. were used to predict bubble-point pressures of CHF{sub 3}+[bmim][PF{sub 6}] (by using the PR EoS and the Soave-Redlich-Kwong equation of state. The bubble-point pressures of CO{sub 2}+IL systems optimized in this study by the PR EoS were also determined using the Soave-Redlich-Kwong equation of state (SRK EoS). In addition, liquid densities of pure ILs were predicted using a generalized correlation proposed by Valderrama and Abu

Volumetric and compressibility behaviour of ionic liquid, 1-n-butyl-3-methylimidazolium hexafluorophosphate and tetrabutylammonium hexafluorophosphate in organic solvents at T = 298.15 K

Energy Technology Data Exchange (ETDEWEB)

Zafarani-Moattar, Mohammed Taghi [Department of Physical Chemistry, Faculty of Chemistry, Excellence of Science for New Materials and Clean Chemistry, Daneshgah Street, University of Tabriz, Tabriz, East Azarbyjan 51664 (Iran, Islamic Republic of)]. E-mail: zafarani47@yahoo.com; Shekaari, Hemayat [Department of Physical Chemistry, Faculty of Chemistry, Excellence of Science for New Materials and Clean Chemistry, Daneshgah Street, University of Tabriz, Tabriz, East Azarbyjan 51664 (Iran, Islamic Republic of)

2006-05-15

Density and speed of sound measurements have been made on the systems containing the ionic liquid 1-n-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF{sub 6}]) and some organic solvents having a wide range of dielectric constants. Similar studies have been carried out for tetrabutylammonium hexafluorophosphate ([TBA][PF{sub 6}]), which has common anion ([PF{sub 6}]{sup -}) with the studied ionic liquid. For the systems investigated, the apparent molar volumes and apparent molar isentropic compressibilities were determined and fitted to the Redlich-Mayer and the Pitzer equations from which the corresponding limiting values were obtained. These limiting values were used to obtain some information about ion-solvent interactions. Furthermore, using the ionic limiting apparent volume values for [TBA]{sup +} from the literature and limiting apparent molar volume for the ionic liquid and [TBA][PF{sub 6}] obtained in this work, the ionic limiting apparent molar volume values for the cation [BMIM]{sup +} in different organic solvents were also estimated.

Corrosion behavior of construction materials for ionic liquid hydrogen compressor

DEFF Research Database (Denmark)

Arjomand Kermani, Nasrin; Petrushina, Irina; Nikiforov, Aleksey Valerievich

2016-01-01

The corrosion behavior of various commercially available stainless steels and nickel-based alloys as possible construction materials for components which are in direct contact with one of five different ionic liquids was evaluated. The ionic liquids, namely: 1-ethyl-3-methylimidazolium triflate, 1...... liquid hydrogen compressor. An electrochemical cell was specially designed, and steady-state cyclic voltammetry was used to measure the corrosion resistance of the alloys in the ionic liquids at 23 °C, under atmospheric pressure. The results showed a very high corrosion resistance and high stability...... for all the alloys tested. The two stainless steels, AISI 316L and AISI 347 showed higher corrosion resistance compared to AISI 321 in all the ionic liquids tested. It was observed that small addition of molybdenum, tantalum, and niobium to the alloys increased the corrosion stability in the ionic liquids...

Activity coefficients at infinite dilution of organic solutes in the ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate using gas-liquid chromatography at T = (313.15, 323.15, and 333.15) K

International Nuclear Information System (INIS)

Olivier, Eugene; Letcher, Trevor M.; Naidoo, Paramespri; Ramjugernath, Deresh

2010-01-01

Activity coefficients at infinite dilution were determined for 24 solutes: n-alkanes, alk-1-enes, alk-1-ynes, cycloalkanes, alkylbenzenes and alcohols in the ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate, [OMIM][PF 6 ], by gas-liquid chromatography at three different temperatures T = (313.15, 323.15, and 333.15) K. The partial molar excess enthalpy values at infinite dilution were calculated from the experimental data over the same temperature range. Capacities and selectivities at infinite dilution for the systems hexane/benzene and methanol/benzene were determined from the experimental data and compared to the literature values for other ionic liquids, as well as for industrial molecular solvents. The influence of the cation and anion of the ionic liquid on the activity coefficient is discussed, as well as the usefulness of [OMIM][PF 6 ] in separating organic liquids.

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

International Nuclear Information System (INIS)

Toshimitsu, Yuichi; Katayama, Yasushi; Miura, Takashi

2012-01-01

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.

Using ethane and butane as probes to the molecular structure of 1-alkyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl] imide ionic liquids.

Science.gov (United States)

Costa Gomes, Margarida F; Pison, Laure; Pensado, Alfonso S; Pádua, Agilio A H

2012-01-01

In this work, we have studied the solubility and the thermodynamic properties of solvation, between 298 and 343 K and at pressures close to atmospheric, of ethane and n-butane in several ionic liquids based on the bis[(trifluoromethyl) sulfonyl]imide anion and on 1-alkyl-3-methylimidazolium cations, [CnC1Im] [NTf2], with alkyl side-chains varying from two to ten carbon atoms. The solubility of butane is circa one order of magnitude larger than that of ethane with mole fractions as high as 0.15 in [C10C1Im][NTf2] at 300 K. The solubilities of both n-butane and ethane gases are higher for ionic liquids with longer alkyl chains. The behaviour encountered is explained by the preferential solvation of the gases in the non-polar domains of the solvents, the larger solubility of n-butane being attributed to the dispersive contributions to the interaction energy. The rise in solubility with increasing size of the alkyl-side chain is explained by a more favourable entropy of solvation in the ionic liquids with larger cations. These conclusions are corroborated by molecular dynamics simulation studies.

Influences of porous reservoir Laplace pressure on emissions from passively fed ionic liquid electrospray sources

Energy Technology Data Exchange (ETDEWEB)

Courtney, Daniel G., E-mail: dcourtney@alum.mit.edu; Shea, Herbert [Ecole Polytechnique Federale de Lausanne (EPFL), Microsystems for Space Technologies Laboratory (LMTS), Neuchatel CH-2002 (Switzerland)

2015-09-07

Passively fed ionic liquid electrospray sources are capable of efficiently emitting a variety of ion beams with promising applications to spacecraft propulsion and as focused ion beams. Practical devices will require integrated or coupled ionic liquid reservoirs; the effects of which have not been explored in detail. Porous reservoirs are a simple, scalable solution. However, we have shown that their pore size can dramatically alter the beam composition. Emitting the ionic liquid 1-ethyl-3-methylimidazolium bis(triflouromethylsulfonyl)amide, the same device was shown to yield either an ion or droplet dominated beam when using reservoirs of small or large pore size, respectively; with the latter having a mass flow in excess of 15 times larger than the former at negative polarity. Another source, emitting nearly purely ionic beams of 1-ethyl-3-methylimidazolium tetrafluoroborate, was similarly shown to emit a significant droplet population when coupled to reservoirs of large (>100 μm) pores; constituting a reduction in propulsive efficiency from greater than 70% to less than 30%. Furthermore, we show that reservoir selection can alter the voltage required to obtain and sustain emission, increasing with smaller pore size.

(Liquid + liquid) equilibrium for the ternary systems {heptane + toluene + 1-allyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide} and {heptane + toluene + 1-methyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide} ionic liquids

International Nuclear Information System (INIS)

Garcia, Silvia; Larriba, Marcos; Garcia, Julian; Torrecilla, Jose S.; Rodriguez, Francisco

2011-01-01

Highlights: → Values of D 1 and D 2 for [mpim][Tf 2 N] are higher than those for [amim][Tf 2 N]. → Values of α 2,1 for [mpim][Tf 2 N] are lower than those for [amim][Tf 2 N]. → Values of D 2 for both ionic liquids are higher than those for sulfolane. → Values of α 2,1 for [mpim][Tf 2 N] are lower than those for sulfolane at x 2 I 2 N] could be considered as an alternative solvent to sulfolane. - Abstract: The (liquid + liquid) equilibrium (LLE) data for two systems containing heptane, toluene, and 1-methyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide ([mpim][Tf 2 N]) or 1-allyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([amim][Tf 2 N]) ionic liquids (ILs) were determined at T = 313.2 K and atmospheric pressure. The effect of a double bond in an alkyl side chain in the imidazolium cation was evaluated in terms of selectivity and extractive capacity. The results show a decrease of the amount of toluene and heptane dissolved in the IL with the allyl group. Thus, the distribution ratios of toluene and heptane of [mpim][Tf 2 N] IL are higher than those of [amim][Tf 2 N] IL. On the other hand, the separation factor of the [amim][Tf 2 N] IL increases comparing to [mpim][Tf 2 N] IL. The NRTL model was used to correlate satisfactorily the experimental LLE data for the two studied ternary systems.

Combined physical and chemical absorption of carbon dioxide in a mixture of ionic liquids

International Nuclear Information System (INIS)

Pinto, Alicia M.; Rodríguez, Héctor; Arce, Alberto; Soto, Ana

2014-01-01

Highlights: • Carbon dioxide can be absorbed in mixtures of two ionic liquids: [C 2 mim][EtSO 4 ] and [C 2 mim][OAc]. • A combination of physical and chemical absorption mechanisms is observed. • The CO 2 absorption capacity of the mixture of ionic liquids decreases with increasing temperature. • [C 2 mim][EtSO 4 ] in the mixture prevents solidification of the product resulting from reaction of [C 2 mim][OAc] and CO 2 . • Density and viscosity studies of the mixture of ionic liquids also lead to synergies, in particular at low temperatures. - Abstract: Ionic liquids have attracted great interest recently as the basis of a potential alternative technology for the capture of carbon dioxide. Beyond the inherent tunability of properties of individual ionic liquids, a further strategy in optimising the ionic liquid sorbent for this application is the use of mixtures of ‘pure’ ionic liquids. Some ionic liquids absorb CO 2 physically, whereas others do so chemically. Both mechanisms of absorption present advantages and disadvantages for a CO 2 capture process operating in a continuous regime. In this work, a mixture of 1-ethyl-3-methylimidazolium acetate (an ionic liquid that reacts chemically with CO 2 ) and 1-ethyl-3-methylimidazolium ethylsulfate (an ionic liquid that absorbs CO 2 only through a physical mechanism) was investigated for the absorption of CO 2 as a function of temperature and at pressures up to 17 bar. The absorption/desorption studies were complemented by the characterisation of thermal and physical properties of the mixture of ionic liquids, which provide extra information on the interactions at a molecular level, and are also critical for the assessment of its suitability for a proposed process and for the subsequent process design

Concentration and electrode material dependence of the voltammetric response of iodide on platinum, glassy carbon and boron-doped diamond in the room temperature ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide

International Nuclear Information System (INIS)

Bentley, Cameron L.; Bond, Alan M.; Hollenkamp, Anthony F.; Mahon, Peter J.; Zhang, Jie

2013-01-01

The electro-oxidation of iodide has been investigated as a function of concentration using steady-state microelectrode voltammetry, transient cyclic voltammetry and linear-sweep semi-integral voltammetry on platinum, glassy carbon and boron-doped diamond electrodes in the room temperature ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide. Two oxidation processes are observed on all of the investigated electrode materials, with the first being assigned to the oxidation of iodide to triiodide (confirmed by UV/visible spectroscopy) and the second being attributed to the oxidation of triiodide to iodine. Iodide oxidation is kinetically more facile on platinum compared to glassy carbon or boron-doped diamond. At elevated bulk iodide concentrations, the nucleation and growth of sparingly soluble electrogenerated iodine at the electrode surface was observed and imaged in situ using optical microscopy. The diffusion coefficient of iodide was determined to be 2.59 (±0.04) × 10 −7 cm 2 s −1 and independent of the bulk concentration of iodide. The steady-state iodide oxidation current measured at a platinum microelectrode was found to be a linear function of iodide concentration, as expected if there are no contributions from non-Stokesian mass-transport processes (electron hopping and/or Grotthuss-type exchange) under the investigated conditions

Solubility data and modeling for sugar alcohols in ionic liquids

International Nuclear Information System (INIS)

Okuniewski, Marcin; Ramjugernath, Deresh; Naidoo, Paramespri; Domańska, Urszula

2014-01-01

Highlights: • Solubility of D-sorbitol and xylitol in six ILs. • The (liquid + liquid) phase equilibrium of (SA + IL) with UCST. • Interesting properties of [BMIM][TDI] IL. • The correlation with NRTL model. - Abstract: Ionic liquids (ILs) are novel media characterized by strong interactions with different organic substances which leads to a wide spectrum of applications involving extraction. Ionic liquids have been used as a solvent for sugar alcohols, sugars and hydrates. This work demonstrates the experimental and theoretical study of (liquid + liquid) phase equilibria for two sugar alcohols, D-sorbitol and xylitol in a few ILs based on different cations and anions (namely, 1-ethyl-1-methylpiperidinium bis(trifluoromethylsulfonyl)imide [EMPIP][NTf 2 ], 1-hexyl-1-methylpiperidinium bis(trifluoromethylsulfonyl)imide [HMPIP][NTf 2 ], N-hexylquinolinium bis(trifluoromethylsulfonyl)imide [HQuin][NTf 2 ], N-hexylisoquinolinium bis(trifluoromethylsulfonyl)imide [HiQuin][NTf 2 ], 1-butyl-1-methylimidazolium 4,5-dicyano-2-(trifluoromethyl)-imidazolide [BMIM][TDI] and 1-(cyanomethyl)-3-methylimidazolium 4,5-dicyano-2-(trifluoromethyl)-imidazolide [CCNMIM][TDI]). This study was conducted to assess the applicability of the studied ILs for dissolution of these biomass-related materials. (Liquid + liquid) phase equilibrium diagrams (LLE) in binary systems (sugar alcohol + ionic liquid) were measured using the dynamic technique. The influence of the chemical structure of both the ionic liquids and sugar alcohols were established and is discussed

(Vapour + liquid) equilibria of ternary systems with ionic liquids using headspace gas chromatography

International Nuclear Information System (INIS)

Mokhtarani, Babak; Gmehling, Juergen

2010-01-01

(Vapour + liquid) equilibrium (VLE) data for the ternary systems (hexane + benzene), (hexane + cyclohexane), (benzene + cyclohexane), and (ethanol + water) with an ionic liquid as entrainer for extractive distillation were measured by headspace gas chromatography. As ionic liquids, 1-hexyl-3-methyl-imidazolium bis (trifluoromethyl-sulfonyl) imide [HMIM][BTI], 1-octyl-3-methyl-imidazolium bis (trifluoromethyl-sulfonyl) imide [OMIM][BTI], 1-octyl-3-methyl-imidazolium trifluoro-methanesulfonate [OMIM][OTF], and 1-butyl-3-methyl-imidazolium trifluoro-methanesulfonate [BMIM][OTF] were used. The experimental data show that the ionic liquids investigated have a great influence on the separation factors of the systems (hexane + benzene), (hexane + cyclohexane), and (benzene + cyclohexane). The experimental data were compared with the predicted results using mod. UNIFAC (Do). The predicted results are in good agreement with the experimental data.

(Vapour + liquid) equilibria of ternary systems with ionic liquids using headspace gas chromatography

Energy Technology Data Exchange (ETDEWEB)

Mokhtarani, Babak [Chemistry and Chemical Engineering Research Center of Iran, P.O. Box 14335-186, Tehran (Iran, Islamic Republic of); Gmehling, Juergen, E-mail: gmehling@tech.chem.uni-oldenburg.d [Carl von Ossietzky Universitaet Oldenburg, Technische Chemie, D-26111 Oldenburg (Germany)

2010-08-15

(Vapour + liquid) equilibrium (VLE) data for the ternary systems (hexane + benzene), (hexane + cyclohexane), (benzene + cyclohexane), and (ethanol + water) with an ionic liquid as entrainer for extractive distillation were measured by headspace gas chromatography. As ionic liquids, 1-hexyl-3-methyl-imidazolium bis (trifluoromethyl-sulfonyl) imide [HMIM][BTI], 1-octyl-3-methyl-imidazolium bis (trifluoromethyl-sulfonyl) imide [OMIM][BTI], 1-octyl-3-methyl-imidazolium trifluoro-methanesulfonate [OMIM][OTF], and 1-butyl-3-methyl-imidazolium trifluoro-methanesulfonate [BMIM][OTF] were used. The experimental data show that the ionic liquids investigated have a great influence on the separation factors of the systems (hexane + benzene), (hexane + cyclohexane), and (benzene + cyclohexane). The experimental data were compared with the predicted results using mod. UNIFAC (Do). The predicted results are in good agreement with the experimental data.

High ionic liquid content polymeric gel membranes: Preparation and performance

Czech Academy of Sciences Publication Activity Database

Jansen, J. C.; Friess, K.; Clarizia, G.; Schauer, Jan; Izák, Pavel

2011-01-01

Roč. 44, č. 1 (2011), s. 39-45 ISSN 0024-9297 R&D Projects: GA ČR GA203/08/0465; GA ČR GAP106/10/1194 Institutional research plan: CEZ:AV0Z40500505; CEZ:AV0Z40720504 Keywords : ionic liquid membrane * gas separation membrane * 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide Subject RIV: CD - Macromolecular Chemistry Impact factor: 5.167, year: 2011

From ionic liquid to electrolyte solution: dynamics of 1-N-butyl-3-N-methylimidazolium tetrafluoroborate/dichloromethane mixtures.

Science.gov (United States)

Hunger, Johannes; Stoppa, Alexander; Buchner, Richard; Hefter, Glenn

2008-10-16

Dielectric spectra have been measured at 25 degrees C for mixtures of the room temperature ionic liquid 1- N-butyl-3- N-methylimidazolium tetrafluoroborate (IL) with dichloromethane (DCM) over the entire composition range at frequencies 0.2 less than or approximately nu/GHz < or = 89. The spectra could be satisfactorily fitted by assuming only two relaxation modes: a Cole-Cole process at lower frequencies and a Debye process at higher frequencies. However, detailed analysis indicated that both spectral features contain additional modes, which could not be resolved due to overlaps. The spectra indicate that the IL appears to retain its chemical character to extraordinarily high levels of dilution ( x IL greater than or approximately 0.5) in DCM. At even higher dilutions ( x IL less than or approximately 0.3), the IL behaves as a conventional but strongly associated electrolyte.

Ionic Liquid based polymer electrolytes for electrochemical sensors

Directory of Open Access Journals (Sweden)

Jakub Altšmíd

2015-09-01

Full Text Available Amperometric NO2 printed sensor with a new type of solid polymer electrolyte and a carbon working electrode has been developed. The electrolytes based on 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonylimide [EMIM][N(Tf2], 1-butyl-3-methylimidazolium trifluoromethanesulfonate [BMIM][CF3SO3] and 1-ethyl-3-methylimidazolium tetrafluoroborate [EMIM][BF4] ionic liquids were immobilized in poly(vinylidene fluoride matrix [PVDF]. The analyte, gaseous nitrogen dioxide, was detected by reduction at -500 mV vs. platinum pseudoreference electrode. The sensors showed a linear behavior in the whole tested range, i.e., 0 - 5 ppm and their sensitivities were in order of 0.3 x∙10-6 A/ppm. The sensor sensitivity was influenced by the electric conductivity of printing formulation; the higher the conductivity, the higher the sensor sensitivity. The rise/recovery times were in order of tens of seconds. The use of  screen printing technology and platinum pseudoreference electrode simplify the sensor fabrication and it does not have any negative effect on the sensor stability.DOI: http://dx.doi.org/10.5755/j01.ms.21.3.7371

Isobaric (vapor + liquid) equilibria of 1-ethyl-3-methylimidazolium ethylsulfate plus (propionaldehyde or valeraldehyde): Experimental data and prediction

International Nuclear Information System (INIS)

Alvarez, Victor H.; Mattedi, Silvana; Aznar, Martin

2011-01-01

Research highlights: → We report density, refraction index, and VLE for (propionaldehyde or valeraldehyde) + [emim][EtSO 4 ]. → The Peng -Robinson + Wong -Sandler + COSMO-SAC model was used to predict density and VLE. → The densities were predicted with deviations below than 2.3%. → The experimental VLE was predicted with deviations below than 1.6%. - Abstract: This paper reports the density, refraction index, and (vapor + liquid) equilibria (VLE) for binary systems {aldehyde + 1-ethyl-3-methylimidazolium ethylsulfate ([emim][EtSO 4 ])}: {propionaldehyde + [emim][EtSO 4 ]} and {valeraldehyde + [emim][EtSO 4 ]}. The uncertainties for the temperature, pressure, and compositions measurements for the phase equilibria are ±0.1 K, ±0.01 kPa and ±0.0004, respectively. A qualitative analysis of the variation of the properties with changes in solvent and temperature was performed. The Peng-Robinson equation of state (PR EoS), coupled with the Wong-Sandler mixing rule (WS), is used to describe the experimental data. To calculate activity coefficients we used three different models: NRTL, UNIQUAC, and COSMO-SAC. Since the predictive liquid activity coefficient model COSMO-SAC is used in the Wong-Sandler mixing rule, the resulting thermodynamic model is a completely predictive one. The prediction results for the density and for the (vapor + liquid) equilibria have a deviation lower than 2.3% and 1.6%, respectively. The (vapor + liquid) equilibria predictions show a good description for the propionaldehyde system and only a qualitative description for the valeraldehyde system.

Determination of cost-effective operating condition for CO{sub 2} capturing using 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid

Energy Technology Data Exchange (ETDEWEB)

Ali, Emad; Alnashef, Inas; Ajbar, Abdelhamid; Mulyono, Sarwono; Hadj-Kali, Mohamed Kamel [King Saud University, Riyadh (Saudi Arabia); Hizaddin, Hanee Farzana [University of Malaya, Kuala Lumpur (Malaysia)

2013-11-15

1-Butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) ionic liquid (IL) is considered for CO{sub 2} capturing in a typical absorption/stripper process. The use of ionic liquids is considered to be cost-effective because it requires less energy for solvent recovery compared to other conventional processes. A mathematical model was developed for the process based on Peng-Robinson (PR) equation of state (EoS). The model was validated with experimental data for CO{sub 2} solubility in [BMIM][BF4]. The model is utilized to study the sorbent effect and energy demand for selected operating pressure at specific CO{sub 2} capturing rates. The energy demand is expressed by the vapor-liquid equilibrium temperature necessary to remove the captured CO{sub 2} from the spent solvent in the regeneration step. It is found that low recovery temperature can be achieved at specific pressure combination for the absorber/stripper units. In fact, the temperature requirement is less than that required by the typical monoethanolamine (MEA) solvent. The effect of the CO{sub 2} loading in the sorbent stream on the process performance is also examined.

Calorimetric determination of the enthalpy of 1-butyl-3-methylimidazolium bromide synthesis: a key quantity in thermodynamics of ionic liquids.

Science.gov (United States)

Paulechka, Yauheni U; Kabo, Andrey G; Blokhin, Andrey V

2009-11-05

The enthalpy of the 1-butyl-3-methylimidazolium bromide [C(4)mim]Br ionic liquid synthesis reaction 1-methylimidazole (liq) + 1-bromobutane (liq) --> [C(4)mim]Br (liq) was determined in a homemade small-volume isoperibol calorimeter to be Delta(r)H degrees (298) = -87.7 +/- 1.6 kJ x mol(-1). The activation energy for this reaction in a homogeneous system E(A) = 73 +/- 4 kJ x mol(-1) was found from the results of calorimetric measurements. The formation enthalpies for the crystalline and liquid [C(4)mim]Br were determined from the calorimetric data: Delta(f)H degrees (298)(cr) = -178 +/- 5 kJ x mol(-1) and Delta(f)H degrees (298)(liq) = -158 +/- 5 kJ x mol(-1). The ideal-gas formation enthalpy of this compound Delta(f)H degrees (298)(g) = 16 +/- 7 kJ x mol(-1) was calculated using the methods of quantum chemistry and statistical thermodynamics. The vaporization enthalpy of [C(4)mim]Br, Delta(vap)H degrees (298) = 174 +/- 9 kJ x mol(-1), was estimated from the experimental and calculated formation enthalpies. It was demonstrated that vapor pressure of this ionic liquid cannot be experimentally determined.

Globular, Sponge-like to Layer-like Morphological Transition in 1-n-Alkyl-3-methylimidazolium Octylsulfate Ionic Liquid Homologous Series.

Science.gov (United States)

Kapoor, Utkarsh; Shah, Jindal K

2018-01-11

Segregation of polar and nonpolar domains in ionic liquids for which either the cation or anion is responsible for inducing nonpolar domains is well understood. On the other hand, information regarding the nanoscale heterogeneities originating due to the presence of nonpolar content on both the ions is rudimentary at this point. The present contribution is aimed at addressing this question and focuses on a molecular dynamics simulation study to probe nanoscale structural and aggregation features of the 1-n-alkyl-3-methylimidazolium [C n mim] octylsulfate [C 8 SO 4 ] ionic liquid homologous series (n = 2, 4, 6, 8, 10, and 12). The objective of this work is to determine the effect of increasing alkyl chain length in the cation on nonpolar domain formation, especially when the alkyl chain lengths from both the ions participate in defining such domains. The results indicate that all the ionic liquids form nonpolar domains, morphology of which gradually changes from globular, sponge-like to layer-like structure with increase in the cationic alkyl chain length. The length of the nonpolar domains calculated from the total structure factor for [C 10 mim][C 8 SO 4 ] is considerably higher than that reported for other imidazolium-based ionic liquid containing smaller anions. The structure factor for [C 12 mim][C 8 SO 4 ] ionic liquid contains multiple intermediate peaks separating the charge alternation peak and pre-peak, which points to nonpolar domains of varying lengths, an observation that remains to be validated. Analysis of the heterogeneous order parameters and orientational correlation functions of the alkyl chains further suggests an increase in the spatial heterogeneity and long-range order along the homologous series. The origin of rich diversity of structures obtained by introducing nonpolar content on both the ions is discussed.

Thermophysical and spectroscopic studies of room temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate in Tritons

International Nuclear Information System (INIS)

Chaudhary, Ganga Ram; Bansal, Shafila; Mehta, S.K.; Ahluwalia, A.S.

2012-01-01

Highlights: ► Thermophysical studies of new formulations of [BMIM][PF 6 ]+TX(45,100) have been made. ► Strong intermolecular interactions between [BMIM][PF 6 ] and TX (45, 100) is observed. ► Magnitude of interactions increases with the addition of oxyethylene groups in TX. ► With rise in temperature, intermolecular interactions increases. ► Spectroscopic studies show that interactions are via aromatic rings of RTIL and TX. - Abstract: The thermophysical properties viz. density ρ, speed of sound u, and specific conductivity κ of pure room temperature ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) and its binary formulations with Triton X-45 and Triton X-100 have been studied over the entire composition range at different temperatures (293.15 to 323.15) K. Excess molar volume V E , deviation in isentropic compressibility ΔK S , partial molar excess volume V i E , deviation in partial molar isentropic compressibility ΔK S,i , deviation in specific conductivity Δκ have also been estimated and analysed. Spectroscopic properties (IR, 1 H and 13 C NMR) of these mixtures have been investigated in order to understand the structural and interactional behaviour of formulations studied. The magnitude of interactions between the two components increases with addition of number of oxyethylene groups in Tritons and with rise in temperature. Spectroscopic measurements indicate that interactions are mainly taking place through the five member ring of room temperature ionic liquid and six member ring of Tritons.

Theoretical investigation of the Te4Br2 molecule in ionic liquids

International Nuclear Information System (INIS)

Elfgen, Roman; Holloczki, Oldamur; Ray, Promit; Kirchner, Barbara; Groh, Matthias F.; Ruck, Michael

2017-01-01

Material synthesis in ionic liquids, at or near room temperature, is currently a subject of immense academic interest. In order to illuminate molecular-level details and the underlying chemistry, we carried out molecular simulations of a single Te 4 Br 2 molecule dissolved in the ionic liquid 1-ethyl-3-methylimidazolium chloride, as well as in the ionic liquid mixed with aluminum chloride. Although the ethyl side chain is much too short to show detailed microheterogeneity, significant structuring with the small chloride anions is seen in case of the pure ionic liquid. In the case of the mixture, formation of larger anionic clusters is distinctly observed and analyzed. Due to the tendency of ionic liquids to dissociate, there is a pronounced shift to elongated Te-Br distances in both investigated solvents. However, only in the AlCl 3 -containing liquid, we observe the reaction of the open chain-like Te 4 Br 2 molecule to a closed square-like Te 4 Br + and AlCl 3 Br - ion. The molecular arrangement of the [Te 4 ] 2+ unit shows negligible deviation from that in the experimental crystal structure. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

The Effect of Microporous Polymeric Support Modification on Surface and Gas Transport Properties of Supported Ionic Liquid Membranes

OpenAIRE

Akhmetshina, Alsu A.; Davletbaeva, Ilsiya M.; Grebenschikova, Ekaterina S.; Sazanova, Tatyana S.; Petukhov, Anton N.; Atlaskin, Artem A.; Razov, Evgeny N.; Zaripov, Ilnaz I.; Martins, Carla F.; Neves, Lu?sa A.; Vorotyntsev, Ilya V.

2015-01-01

Microporous polymers based on anionic macroinitiator and toluene 2,4-diisocyanate were used as a support for 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]) and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([emim][Tf2N]) immobilization. The polymeric support was modified by using silica particles associated in oligomeric media, and the influence of the modifier used on the polymeric structure was studied. The supported ionic liquid membranes (SILMs) were tested ...

Electrolytic conductivity and molar heat capacity of two aqueous solutions of ionic liquids at room-temperature: Measurements and correlations

International Nuclear Information System (INIS)

Lin Peiyin; Soriano, Allan N.; Leron, Rhoda B.; Li Menghui

2010-01-01

As part of our systematic study on physicochemical characterization of ionic liquids, in this work, we report new measurements of electrolytic conductivity and molar heat capacity for aqueous solutions of two 1-ethyl-3-methylimidazolium-based ionic liquids, namely: 1-ethyl-3-methylimidazolium dicyanamide and 1-ethyl-3-methylimidazolium 2-(2-methoxyethoxy) ethylsulfate, at normal atmospheric condition and for temperatures up to 353.2 K. The electrolytic conductivity and molar heat capacity were measured by a commercial conductivity meter and a differential scanning calorimeter (DSC), respectively. The estimated experimental uncertainties for the electrolytic conductivity and molar heat capacity measurements were ±1% and ±2%, respectively. The property data are reported as functions of temperature and composition. A modified empirical equation from another researcher was used to correlate the temperature and composition dependence of the our electrolytic conductivity results. An excess molar heat capacity expression derived using a Redlich-Kister type equation was used to represent the temperature and composition dependence of the measured molar heat capacity and calculated excess molar heat capacity of the solvent systems considered. The correlations applied represent the our measurements satisfactorily as shown by an acceptable overall average deviation of 6.4% and 0.1%, respectively, for electrolytic conductivity and molar heat capacity.

Direct synthesis of silver nanoparticles in ionic liquid

International Nuclear Information System (INIS)

Corrêa, Cíntia M.; Bizeto, Marcos A.; Camilo, Fernanda F.

2016-01-01

Ionic liquids have structural organization at nanoscale that can trigger the spontaneous ordering of structures in nanoscopic range. Due to this characteristic, several metal nanoparticles have been prepared in this media. In this paper, we describe the direct preparation of silver nanoparticles in the following imidazolium ionic liquids: 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1,2-dimethyl-3-butylimidazolium bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-octyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, and in citrate tetrabutylammonium, that is an ionic liquid that acts as solvent and reducing agent at the same time. We also evaluated the morphology of the nanoparticles and the stability of the dispersions. Spherical silver nanoparticles with surface Plasmon bands in the range of 400–430 nm were produced in all the ionic liquids, with the only exception for the 1-octyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide that produced a black precipitate. The best results were obtained by using 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide and citrate tetrabutylammonium ionic liquids. The former resulted in concentrated spherical silver nanoparticles dispersion (ca. 1.0 mM of Ag) with diameters ranging from 6 to 12 nm and by adding polyvinylpyrrolidone (PVP) to the dispersions they became stable for at least 1 month. The citrate tetrabutylammonium ionic liquid produced even more concentrated dispersion of spherical silver nanoparticles with diameters ranging from 2 to 6 nm. These dispersions were quite stable without the need of PVP, since the Plasmon band in the electronic absorption spectra remained unaltered for months after the preparation. The citrate tetrabutylammonium ionic liquid offers a slow kinetic for the silver nanoparticle formation as the citrate is a milder reducing agent than borohydride.Graphical Abstract

Direct synthesis of silver nanoparticles in ionic liquid

Energy Technology Data Exchange (ETDEWEB)

Corrêa, Cíntia M.; Bizeto, Marcos A.; Camilo, Fernanda F., E-mail: ffcamilo@unifesp.br [Universidade Federal de São Paulo, Laboratório de Materiais Híbridos, Departamento de Ciências Exatas e da Terra, Instituto de Ciências Ambientais, Químicas e Farmacêuticas (Brazil)

2016-05-15

Ionic liquids have structural organization at nanoscale that can trigger the spontaneous ordering of structures in nanoscopic range. Due to this characteristic, several metal nanoparticles have been prepared in this media. In this paper, we describe the direct preparation of silver nanoparticles in the following imidazolium ionic liquids: 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, 1,2-dimethyl-3-butylimidazolium bis(trifluoromethanesulfonyl)imide, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-octyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, and in citrate tetrabutylammonium, that is an ionic liquid that acts as solvent and reducing agent at the same time. We also evaluated the morphology of the nanoparticles and the stability of the dispersions. Spherical silver nanoparticles with surface Plasmon bands in the range of 400–430 nm were produced in all the ionic liquids, with the only exception for the 1-octyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide that produced a black precipitate. The best results were obtained by using 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide and citrate tetrabutylammonium ionic liquids. The former resulted in concentrated spherical silver nanoparticles dispersion (ca. 1.0 mM of Ag) with diameters ranging from 6 to 12 nm and by adding polyvinylpyrrolidone (PVP) to the dispersions they became stable for at least 1 month. The citrate tetrabutylammonium ionic liquid produced even more concentrated dispersion of spherical silver nanoparticles with diameters ranging from 2 to 6 nm. These dispersions were quite stable without the need of PVP, since the Plasmon band in the electronic absorption spectra remained unaltered for months after the preparation. The citrate tetrabutylammonium ionic liquid offers a slow kinetic for the silver nanoparticle formation as the citrate is a milder reducing agent than borohydride.Graphical Abstract.

Phase Behaviour of 1-Ethyl-3-methylimidazolium Thiocyanate Ionic Liquid with Catalytic Deactivated Compounds and Water at Several Temperatures: Experiments and Theoretical Predictions

Directory of Open Access Journals (Sweden)

Ramalingam Anantharaj

2011-01-01

Full Text Available Density, surface tension and refractive index were determined for the binary mixture of catalytic deactivated compounds with 1-ethyl-3-methylimidazolium thiocyanate {[EMIM][SCN]} at temperature of (298.15 to 323.15 K. For all the compounds with ILs, the densities varied linearly in the entire mole fraction with increasing temperature. From the obtained data, the excess molar volume and deviation of surface tension and refractive index have been calculated. A strong interaction was found between similar (cation-thiophene or cation-pyrrole compounds. The interaction of IL with dissimilar compounds such as indoline and quinoline and other multiple ring compounds was found to strongly depend on the composition of IL at any temperatures. For the mixtures, the surface tension decreases in the order of: thiophene > quinoline > pyridine > indoline > pyrrole > water. In general from the excess volume studies, the IL-sulphur/nitrogen mixture has stronger interaction as compared to IL-IL, thiophene-thiophene or pyrrole-pyrrole interaction. The deviation of surface tension was found to be inversely proportional to deviation of refractive index. The quantum chemical based COSMO-RS was used to predict the non-ideal liquid phase activity coefficient for all mixtures. It indicated an inverse relation between activity coefficient and excess molar volumes.

Ionic association and solvation of the ionic liquid 1-hexyl-3-methylimidazolium chloride in molecular solvents revealed by vapor pressure osmometry, conductometry, volumetry, and acoustic measurements.

Science.gov (United States)

Sadeghi, Rahmat; Ebrahimi, Nosaibah

2011-11-17

A systematic study of osmotic coefficient, conductivity, volumetric and acoustic properties of solutions of ionic liquid 1-hexyl-3-methylimidazolium chloride ([C(6)mim][Cl]) in various molecular solvents has been made at different temperatures in order to study of ionic association and solvation behavior of [C(6)mim][Cl] in different solutions. Precise measurements on electrical conductances of solutions of [C(6)mim][Cl] in water, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, and acetonitrile at 293.15, 298.15, and 303.15 K are reported and analyzed with Barthel's low-concentration chemical model (lcCM) to obtain the limiting molar conductivities and association constants of this ionic liquid in the investigated solvents. Strong ion pairing was found for the ionic liquid in 2-propanol, 1-butanol, and 1-propanol, whereas ion association in acetonitrile, methanol and ethanol is rather weak and in water the ionic liquid is fully dissociated. In the second part of this work, the apparent molar volumes and isentropic compressibilities of [C(6)mim][Cl] in water, methanol, ethanol, acetonitrile, 1-propanol, 2-propanol, and 1-butanol are obtained at the 288.15-313.15 K temperature range at 5 K intervals at atmospheric pressure from the precise measurements of density and sound velocity. The infinite dilution apparent molar volume and isentropic compressibility values of the free ions and ion pairs of [C(6)mim][Cl] in the investigated solvents as well as the excess molar volume of the investigated solutions are determined and their variations with temperature and type of solvents are also studied. Finally, the experimental measurements of osmotic coefficient at 318.15 K for binary solutions of [C(6)mim][Cl] in water, methanol, ethanol, 2-propanol, and acetonitrile are taken using the vapor pressure osmometry (VPO) method and from which the values of the solvent activity, vapor pressure, activity coefficients, and Gibbs free energies are calculated. The results are

(Vapour + liquid) equilibria, volumetric and compressibility behaviour of binary and ternary aqueous solutions of 1-hexyl-3-methylimidazolium chloride, methyl potassium malonate, and ethyl potassium malonate

International Nuclear Information System (INIS)

Sadeghi, Rahmat; Mahdavi, Adibeh

2012-01-01

Highlights: ► VLE and volumetry of binary and ternary [C 6 mim][Cl], MPM and EPM aqueous solutions. ► Constant a w lines show small negative deviation from the linear isopiestic relation. ► Solute–water interactions follow the order: EPM > MPM > [C 6 mim][Cl]. ► MPM and EPM have a very weak salting-out effect on [C 6 mim][Cl] aqueous solutions. - Abstract: (Vapour + liquid) equilibrium data (water activity, vapour pressure, osmotic coefficient, and activity coefficient) of binary aqueous solutions of 1-hexyl-3-methylimidazolium chloride ([C 6 mim][Cl]), methyl potassium malonate, and ethyl potassium malonate and ternary {[C 6 mim][Cl] + methyl potassium malonate} and {[C 6 mim][Cl] + ethyl potassium malonate} aqueous solutions were obtained through the isopiestic method at T = 298.15 K. These results reveal that the ionic liquid behaves as surfactant-like and aggregates in aqueous solutions at molality about 0.4 mol · kg −1 . The constant water activity lines of all the ternary systems investigated show small negative deviations from the linear isopiestic relation (Zdanovskii–Stokes–Robinson rule) derived using the semi-ideal hydration model. The density and speed of sound measurements were carried out on solutions of methyl potassium malonate and ethyl potassium malonate in water and of [C 6 mim][Cl] in aqueous solutions of 0.25 mol · kg −1 methyl potassium malonate and ethyl potassium malonate at T = (288.15 to 308.15) K at atmospheric pressure. From the experimental density and speed of sound data, the values of the apparent molar volume, apparent molar isentropic compressibility and excess molar volume were evaluated and from which the infinite dilution apparent molar volume and infinite dilution apparent molar isentropic compressibility were calculated at each temperature. Although, there are no clear differences between the values of the apparent molar volume of [C 6 mim][Cl] in pure water and in methyl potassium malonate or ethyl

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

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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.

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

International Nuclear Information System (INIS)

Shyamala Devi, V.; Maji, S.; Viswanathan, K.S.

2011-01-01

The newly prepared ionic liquid, 1-butyl-3-methylimidazolium benzoate, ([bmim][BA]), was found to enhance the fluorescence of Eu 3+ and Tb 3+ . 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 Eu 3+ 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][Tf 2 N]), as a solvent. In the case of Tb 3+ , the emission from the lanthanide was masked by the strong emission from the ionic liquid in the region 450-580 nm. The long lived Tb 3+ 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][Tf 2 N], 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, Eu 3+ and Tb 3+ 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

Physico-Chemical Properties and Phase Behavior of the Ionic Liquid-β-Cyclodextrin Complexes

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Michał Wlazło

2013-08-01

Full Text Available The solubility of β-cyclodextrin (β-CD in ionic liquids (ILs and the activity coefficients at infinite dilution ( of more than 20 solutes (alkanes, aromatic hydrocarbons, alcohols were measured in four chosen ionic liquids, their mixtures with β-CD, and in the β-CD at high temperatures from 338 to 398 K using the inverse gas chromatography. The intermolecular interactions, inclusion complexes and the possible increasing of the solubility of β-CD in water using the IL are presented. The solubility of β-CD in ten chosen hydrophobic ILs at the temperature T = 423 K was detected. The solid-liquid phase diagrams (SLE of {IL (1 + β-CD (2} binary systems at the high mole fraction of the IL were measured for three systems (1-ethyl-3-methylimidazolium chloride, [EMIM][Cl], 1-ethyl-3-methylimidazolium bromide, [EMIM][Br]; and for 1-butyl-3-methylimidazolium chloride, [BMIM][Cl]. The eutectic points were determined at the high IL concentration for all binary systems. The intermolecular interaction and the possibility of inclusion complexes of the IL and/or solvents with β-CD were discussed. The infrared spectroscopy, IR was used for the description of the intermolecular interactions in the (β-CD + IL systems. It was shown via the activity coefficients at infinite dilution results that the inclusion complexes are dependent on the temperature. The addition of β-CD to the IL does not improve the selectivity of the separation of the aliphatics from aromatics.

The effects of a co-solvent on fabrication of cellulose acetate membranes from solutions in 1-ethyl-3-methylimidazolium acetate

KAUST Repository

Kim, Dooli

2016-08-15

Ionic liquids have been considered green solvents for membrane fabrication. However, the high viscosity of their polymer solutions hinders the formation of membranes with strong mechanical properties. In this study, acetone was explored as a co-solvent with the ionic liquid 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc) to dissolve cellulose acetate. The effects of acetone on the thermodynamic and kinetic aspects of the polymer solutions were studied and the physicochemical properties and separation capability of their resultant membranes were analyzed. The Hansen solubility parameters of [EMIM]OAc were measured by the software HSPiP and these data demonstrated that acetone was a suitable co-solvent to increase the solubility of cellulose acetate. The Gibbs free energy of mixing ΔGm was estimated to determine the proper composition of the polymer solution with better solubility. The study of the kinetics of phase separation showed that the demixing rate of the CA polymer solution in acetone and [EMIM]OAc was higher than that for solutions in [EMIM]OAc only. The membranes prepared from the former solution had higher water permeance and better mechanical stability than those prepared from the later solution. Adding acetone as a co-solvent opened the opportunity of fabricating membranes with higher polymer concentrations for higher separation capability and better mechanical properties. © 2016

The effects of a co-solvent on fabrication of cellulose acetate membranes from solutions in 1-ethyl-3-methylimidazolium acetate

KAUST Repository

Kim, Dooli; Le, Ngoc Lieu; Nunes, Suzana Pereira

2016-01-01

Ionic liquids have been considered green solvents for membrane fabrication. However, the high viscosity of their polymer solutions hinders the formation of membranes with strong mechanical properties. In this study, acetone was explored as a co-solvent with the ionic liquid 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc) to dissolve cellulose acetate. The effects of acetone on the thermodynamic and kinetic aspects of the polymer solutions were studied and the physicochemical properties and separation capability of their resultant membranes were analyzed. The Hansen solubility parameters of [EMIM]OAc were measured by the software HSPiP and these data demonstrated that acetone was a suitable co-solvent to increase the solubility of cellulose acetate. The Gibbs free energy of mixing ΔGm was estimated to determine the proper composition of the polymer solution with better solubility. The study of the kinetics of phase separation showed that the demixing rate of the CA polymer solution in acetone and [EMIM]OAc was higher than that for solutions in [EMIM]OAc only. The membranes prepared from the former solution had higher water permeance and better mechanical stability than those prepared from the later solution. Adding acetone as a co-solvent opened the opportunity of fabricating membranes with higher polymer concentrations for higher separation capability and better mechanical properties. © 2016

Study of the PVA hydrogel behaviour in 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid

Directory of Open Access Journals (Sweden)

2011-02-01

Full Text Available The present paper aims at studying the behaviour of the poly(vinyl alcohol [PVA] cryogel in the presence of 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]+[BF4]– aqueous solutions with various concentrations. The gravimetric method showed that the swollen PVA cryogels exhibit mechanically active behaviour. PVA cryogels showed shrinking in the presence of ionic liquid, (IL, and re-swelling in the presence of distilled water. The re-swelling is not completely reversible, due to the influence of the IL ions on the gel morphology. The Fourier transform infrared (FTIR spectra have indicated no chemical interaction between the PVA and the studied IL, but highlighted the gel crystallinity change as a function of IL concentration, as well as changes in the bound water amount. Rheological analyses showed dominating plastifying effect of the cation at a lower IL concentration and dominating kosmotropic effect of the anion at a higher IL concentration. A phenomenological kinetic equation that takes into account both fluxes of matters, in and out of the gel, is proposed, explaining the alteration of the gel properties when it comes in contact with BMIMBF4 solutions.

Interface adsorption and micelle formation of ionic liquid 1-hexyl-3-methylimidazolium chloride in the toluene + water system

International Nuclear Information System (INIS)

Asadabadi, Simin; Saien, Javad; Khakizadeh, Vahid

2013-01-01

Highlights: • Introducing the used ionic liquid causes a significant reduction in toluene–water interfacial tension. • Temperature has a significant effect on the interfacial tension as well as forming micelle in bulk solution. • The Frumkin model provides a suitable isotherm for the studied system. • Tendency, effectiveness of adsorption and repulsive interaction vary with increasing temperature. • Under saturated interface, entropy and energy changes associated with adsorption show a maximum value at about 303.2 K. -- Abstract: The influence of synthesized ionic liquid 1-hexyl-3-methylimidazolium chloride adsorption on equilibrium interfacial tension of toluene–water was studied within concentration range of (1.00 ⋅ 10 −4 to 6.00 ⋅ 10 −1 ) mol · dm −3 and temperature range of (293.2 to 313.2) K. Very similar to conventional surfactants, the interfacial tension was decreased with both of these parameters. Meanwhile, the CMC values showed a minimum value within the temperature range studied. The Frumkin adsorption isotherm that accounts for the non-ideal adsorption at the interface showed adequately well for modeling the experimental results. Accordingly quantities like interface excess concentration, adsorption tendency and interaction parameter between adsorbed molecules were obtained at different temperatures. Entropy and energy changes associated with adsorption were also obtained from the temperature dependency of interfacial tension. The adsorption tendency and efficiency increased with temperature, and the maximum interface excess concentration and electrostatic repulsion were achieved at about T = 303.2 K

Sono- and photoelectrocatalytic processes for the removal of ionic liquids based on the 1-butyl-3-methylimidazolium cation.

Science.gov (United States)

Mena, Ismael F; Cotillas, Salvador; Díaz, Elena; Sáez, Cristina; Mohedano, Ángel F; Rodrigo, Manuel A

2017-12-06

In this work, sono- and photoelectrolysis of synthetic wastewaters polluted with the ionic liquids 1-Butyl-3-methylimidazolium acetate (BmimAc) and chloride (BmimCl) were investigated with diamond anodes. The results were compared to those attained by enhancing bare electrolysis with irradiation by UV light or with the application of high-frequency ultrasound (US). Despite its complex heterocyclic structure, the Bmim + cation was successfully depleted with the three technologies that were tested and was mainly transformed into four different organic intermediates, an inorganic nitrogen species and carbon dioxide. Regardless of the technology that was evaluated, removal of the heterocyclic ring is much less efficient (and much slower) than oxidation of the counter ion. In turn, the counter ion influences the rate of removal of the ionic liquid cation. Thus, the electrolysis and photoelectrolysis of BmimAc are much less efficient than sonoelectrolysis, but their differences become much less important in the case of BmimCl. In this later case, the most efficient technology is photoelectrolysis. This result is directly related to the generation of free radicals in the solution by irradiation of the electrochemical system with UV light, which contributes significantly to the removal of Bmim + . Copyright © 2017 Elsevier B.V. All rights reserved.

Electrodeposition behavior of nickel and nickel-zinc alloys from the zinc chloride-1-ethyl-3-methylimidazolium chloride low temperature molten salt

International Nuclear Information System (INIS)

Gou Shiping; Sun, I.-W.

2008-01-01

The electrodeposition of nickel and nickel-zinc alloys was investigated at polycrystalline tungsten electrode in the zinc chloride-1-ethyl-3-methylimidazolium chloride molten salt. Although nickel(II) chloride dissolved easily into the pure chloride-rich 1-ethyl-3-methylimidazolium chloride ionic melt, metallic nickel could not be obtained by electrochemical reduction of this solution. The addition of zinc chloride to this solution shifted the reduction of nickel(II) to more positive potential making the electrodeposition of nickel possible. The electrodeposition of nickel, however, requires an overpotential driven nucleation process. Dense and compact nickel deposits with good adherence could be prepared by controlling the deposition potential. X-ray powder diffraction measurements indicated the presence of crystalline nickel deposits. Non-anomalous electrodeposition of nickel-zinc alloys was achieved through the underpotential deposition of zinc on the deposited nickel at a potential more negative than that of the deposition of nickel. X-ray powder diffraction and energy-dispersive spectrometry measurements of the electrodeposits indicated that the composition and the phase types of the nickel-zinc alloys are dependent on the deposition potential. For the Ni-Zn alloy deposits prepared by underpotential deposition of Zn on Ni, the Zn content in the Ni-Zn was always less than 50 atom%

Measurement and correlation of vapor-liquid equilibria for a binary system containing 1-butyl-3-methylimidazolium tridecafluorohexyl sulfonate and carbon dioxide

Energy Technology Data Exchange (ETDEWEB)

Hong, Soon Kang; Park, Yoon Kook [Hongik University, Sejong (Korea, Republic of)

2016-01-15

Using a high-pressure variable-volume view cell, the vapor-liquid equilibria of the binary system CO{sub 2} and 1-butyl-3-methylimidazolium tridecafluorohexylsulfonate ([BMIM][TDfO]) were determined. The CO{sub 2} mole fraction ranged from 0.104 to 0.952 over a temperature range of 298.2-323.2 K. Both the Peng-Robinson and Soave-Redlich- Kwong equations of state were applied with two different mixing rules to correlate with the experimentally obtained results. Increasing the alkyl chain length in perfluorinated sulfonate anion mother structure from methyl to hexyl markedly increased the CO{sub 2} solubility. To investigate the effect of the number of fluorine atoms in the anion on the phase behavior of imidazolium-based ionic liquid, these experimental results were then compared with those reported in previous experimental studies of 1-alkyl-3-methylimidazolium cations-including ionic liquid+CO{sub 2} binary system.

Measurement and correlation of vapor-liquid equilibria for a binary system containing 1-butyl-3-methylimidazolium tridecafluorohexyl sulfonate and carbon dioxide

International Nuclear Information System (INIS)

Hong, Soon Kang; Park, Yoon Kook

2016-01-01

Using a high-pressure variable-volume view cell, the vapor-liquid equilibria of the binary system CO 2 and 1-butyl-3-methylimidazolium tridecafluorohexylsulfonate ([BMIM][TDfO]) were determined. The CO 2 mole fraction ranged from 0.104 to 0.952 over a temperature range of 298.2-323.2 K. Both the Peng-Robinson and Soave-Redlich- Kwong equations of state were applied with two different mixing rules to correlate with the experimentally obtained results. Increasing the alkyl chain length in perfluorinated sulfonate anion mother structure from methyl to hexyl markedly increased the CO 2 solubility. To investigate the effect of the number of fluorine atoms in the anion on the phase behavior of imidazolium-based ionic liquid, these experimental results were then compared with those reported in previous experimental studies of 1-alkyl-3-methylimidazolium cations-including ionic liquid+CO 2 binary system.

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

Science.gov (United States)

Deyab, M. A.

2018-06-01

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

Aerogels from Chitosan Solutions in Ionic Liquids

Directory of Open Access Journals (Sweden)

Gonzalo Santos-López

2017-12-01

Full Text Available Chitosan aerogels conjugates the characteristics of nanostructured porous materials, i.e., extended specific surface area and nano scale porosity, with the remarkable functional properties of chitosan. Aerogels were obtained from solutions of chitosan in ionic liquids (ILs, 1-butyl-3-methylimidazolium acetate (BMIMAc, and 1-ethyl-3-methyl-imidazolium acetate (EMIMAc, in order to observe the effect of the solvent in the structural characteristics of this type of materials. The process of elaboration of aerogels comprised the formation of physical gels through anti-solvent vapor diffusion, liquid phase exchange, and supercritical CO2 drying. The aerogels maintained the chemical identity of chitosan according to Fourier transform infrared spectrophotometer (FT-IR spectroscopy, indicating the presence of their characteristic functional groups. The internal structure of the obtained aerogels appears as porous aggregated networks in microscopy images. The obtained materials have specific surface areas over 350 m2/g and can be considered mesoporous. According to swelling experiments, the chitosan aerogels could absorb between three and six times their weight of water. However, the swelling and diffusion coefficient decreased at higher temperatures. The structural characteristics of chitosan aerogels that are obtained from ionic liquids are distinctive and could be related to solvation dynamic at the initial state.

Separation of toluene from alkanes using 1-ethyl-3-methylpyridinium ethylsulfate ionic liquid at T = 298.15 K and atmospheric pressure

International Nuclear Information System (INIS)

Gonzalez, Emilio J.; Calvar, Noelia; Gonzalez, Begona; Dominguez, Angeles

2010-01-01

In this paper, the separation of toluene from aliphatic hydrocarbons (heptane, or octane, or nonane) was analyzed by solvent extraction with 1-ethyl-3-methylpyridinium ethylsulfate ionic liquid, [EMpy][ESO 4 ]. Liquid-liquid equilibrium (LLE) data for the ternary systems {heptane (1) + toluene (2) + [EMpy][ESO 4 ] (3)}, {octane (1) + toluene (2) + [EMpy][ESO 4 ] (3)}, and {nonane (1) + toluene (2) + [EMpy][ESO 4 ] (3)} were obtained by measurements at T = 298.15 K and atmospheric pressure. The selectivity, % removal of aromatic, and solute distribution ratio, obtained from experimental equilibrium results, were used to determine the ability of [EMpy][ESO 4 ] as a solvent. The degree of consistency of the experimental LLE values was ascertained using the Othmer-Tobias and Hand equations. The experimental results for the ternary systems were correlated with the NRTL model. Finally, the results obtained were compared with other ionic liquids and other solvents.

Interplay Between Structure and Conductivity in 1-Ethyl-3-methylimidazolium tetrafluoroborate/(δ-MgCl2)f Electrolytes for Magnesium Batteries

International Nuclear Information System (INIS)

Bertasi, Federico; Vezzù, Keti; Nawn, Graeme; Pagot, Gioele; Di Noto, Vito

2016-01-01

The synthesis, physicochemical properties and conductivity mechanism of a family of ionic liquid-based electrolytes for use in secondary Mg batteries are reported. The electrolytes are obtained by dissolving controlled amounts of δ-MgCl 2 salt into the ionic liquid (IL) 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF 4 ) which acts as a solvent. δ-MgCl 2 consists of an inorganic ribbon of Mg atoms covalently bonded together through bridging chlorine atoms. Due to this peculiar structural motif, with respect to the electrolytes based on conventional Mg salts, it is possible to achieve electrolytes of higher Mg concentration. Thus, concatenated anionic complexes bridged via halogen atoms are formed, improving the electrochemical performance of these materials. Electrolytes with a general formula EMImBF 4 /(δ-MgCl 2 ) f with f ranging from 0 to 0.117 are obtained. The composition of the obtained materials is determined by Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES). The properties of these systems are investigated by means of Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), and vibrational spectroscopy in both medium (MIR) and far infrared (FIR). Finally, Broadband Electrical Spectroscopy (BES) is carried out with the aim to elucidate the electrical response of the electrolytes in terms of their polarization and relaxation phenomena and to propose a conductivity mechanism. At 20 °C the highest conductivity (0.007 S/cm) is observed for the electrolyte with c Mg = 0.00454 mol Mg /kg IL .

Novel room temperature ionic liquid for fluorescence enhancement of Eu{sup 3+} and Tb{sup 3+}

Energy Technology Data Exchange (ETDEWEB)

Shyamala Devi, V.; Maji, S. [Materials Chemistry Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Viswanathan, K.S., E-mail: vish@igcar.gov.i [Materials Chemistry Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India)

2011-04-15

The newly prepared ionic liquid, 1-butyl-3-methylimidazolium benzoate, ([bmim][BA]), was found to enhance the fluorescence of Eu{sup 3+} and Tb{sup 3+}. 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 Eu{sup 3+} 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][Tf{sub 2}N]), as a solvent. In the case of Tb{sup 3+}, the emission from the lanthanide was masked by the strong emission from the ionic liquid in the region 450-580 nm. The long lived Tb{sup 3+} 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][Tf{sub 2}N], 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: {yields}The use of an ionic liquid to enhance the fluorescence of lanthanides, Eu{sup 3+} and Tb{sup 3+} is discussed in this paper. {yields} This study represents the first report of the use of a tailored ionic liquid for the purposes of fluorescence enhancement. {yields} The fluorescence enhancement is achieved both a process of ligand sensitization, as well as reducing the non-radiative decay channels. {yields

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

Science.gov (United States)

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

2016-12-01

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

Volumetric properties for glycine and L-serine in aqueous solutions of 1-Ethyl-3-methylimidazolium hydrogen sulfate ([Emim][HSO4]) at T = (293.15–313.15) K and ambient pressure

International Nuclear Information System (INIS)

Rafiee, Hamid Reza; Frouzesh, Farshid

2016-01-01

Highlights: • Ternary systems (amino acid + ionic liquid + H 2 O) are considered. • Volumetric properties including density, V φ , ΔV φ 0 and E φ 0 are determined. • Glycine and L-serine were amino acids and [Emim][HSO 4 ] was IL studied. • V φ values for amino acids increased with both concentration of amino acids and temperature. • Both studied amino acids act as structure maker in ternary systems. - Abstract: By using the volumetric properties, the solute–solvent interactions are studied in the ternary (glycine + 1-Ethyl-3-methylimidazolium hydrogen sulfate [Emim][HSO 4 ] + water) and (L-serine + 1-Ethyl-3-methylimidazolium hydrogen sulfate [Emim][HSO 4 ] + water) systems. For this purpose, the apparent molar volumes, V φ , are calculated from the experimental density data. To obtain limiting apparent molar volumes V φ 0 , the apparent molar volume values are fitted to the Redlich-Mayer type equation. Then the limiting apparent molar volumes of transfer, ΔV φ 0 , for studied amino acids from water to aqueous solutions of ionic liquid (IL) are calculated. The results showed that the ΔV φ 0 values are negative for both ternary systems at all temperatures. The limiting apparent molar expansibility E φ 0 values have been obtained from the first derivative of limiting apparent molar volumes with respect to temperature. The values of second derivative of limiting apparent molar volumes respect to temperature show the structure making or breaking ability of glycine and L-serine in studied IL aqueous solutions. The results indicated that glycine and L-serine act as structure maker in studied solutions. McMillan–Mayer theory is used for evaluating the interaction parameters. Also the hydration number, n H , for both amino acids in ternary solutions has been reported.

Theoretical investigation of the Te{sub 4}Br{sub 2} molecule in ionic liquids

Energy Technology Data Exchange (ETDEWEB)

Elfgen, Roman [Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstr. 4+6, 53115, Bonn (Germany); Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45413, Muehlheim an der Ruhr (Germany); Holloczki, Oldamur; Ray, Promit; Kirchner, Barbara [Mulliken Center for Theoretical Chemistry, University of Bonn, Beringstr. 4+6, 53115, Bonn (Germany); Groh, Matthias F. [Department of Chemistry and Food Chemistry, Dresden University of Technology, 01062, Dresden (Germany); Ruck, Michael [Department of Chemistry and Food Chemistry, Dresden University of Technology, 01062, Dresden (Germany); Max Planck Institute for Chemical Physics of Solids, Noethnitzer Str. 40, 01187, Dresden (Germany)

2017-01-15

Material synthesis in ionic liquids, at or near room temperature, is currently a subject of immense academic interest. In order to illuminate molecular-level details and the underlying chemistry, we carried out molecular simulations of a single Te{sub 4}Br{sub 2} molecule dissolved in the ionic liquid 1-ethyl-3-methylimidazolium chloride, as well as in the ionic liquid mixed with aluminum chloride. Although the ethyl side chain is much too short to show detailed microheterogeneity, significant structuring with the small chloride anions is seen in case of the pure ionic liquid. In the case of the mixture, formation of larger anionic clusters is distinctly observed and analyzed. Due to the tendency of ionic liquids to dissociate, there is a pronounced shift to elongated Te-Br distances in both investigated solvents. However, only in the AlCl{sub 3}-containing liquid, we observe the reaction of the open chain-like Te{sub 4}Br{sub 2} molecule to a closed square-like Te{sub 4}Br{sup +} and AlCl{sub 3}Br{sup -} ion. The molecular arrangement of the [Te{sub 4}]{sup 2+} unit shows negligible deviation from that in the experimental crystal structure. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Anodic behavior of uranium in AlCl3-1-ethyl-3-methyl-imidazolium chloride ionic liquid

Science.gov (United States)

Jiang, Yidong; Luo, Lizhu; Wang, Shaofei; Bin, Ren; Zhang, Guikai; Wang, Xiaolin

2018-01-01

The oxidation state of metals unambiguously affects its anodic behavior in ionic liquid. We systematically investigated the anodic behavior of uranium with different surface oxidation states by electrochemical measurements, spectroscopic methods and surface analysis techniques. In the anodic process, metal uranium can be oxidized to U3+. The corresponding products accumulated on the metal/ILs interface will form a viscous layer. The anodic behavior of uranium is also strongly dependent upon the surface oxide states including thickness and homogeneity of the oxide film. With an increase in the thickness of oxide film, it will be breached at potentials in excess of a critical value. A uniform oxide on uranium surface can be breached evenly, and then the underlying metal starts to dissolve forming a viscous layer which can facilitate uniformly stripping of oxide, thus giving an oxide-free surface. Otherwise, a nonuniform oxide can result in a severe pitted surface with residue oxygen.

Volumetric Properties of the Ionic Liquid, 1-Butyl-3-methylimidazolium Tetrafluoroborate, in Organic Solvents at T = 298.15K

Science.gov (United States)

Shekaari, Hemayat; Zafarani-Moattar, Mohammed Taghi

2008-04-01

Apparent molar volumes, V_φ , and compressibilities, kappa _φ , of 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF4]) have been determined from precise density and speed-of-sound measurements in organic solvents, methanol (MeOH), acetonitrile (MeCN), tetrahydrofuran (THF), N, N-dimethylacetamide (DMA), and dimethylsulfoxide (DMSO) in the dilute region of the ionic liquid. Corresponding values at infinite dilution are estimated by the Redlich-Mayer and Pitzer equations. The results have been interpreted by the interaction of the [BMIm][BF4] in the organic solvents. Results show that the structure and dielectric constant of the organic solvents play an important role for the ion-solvent interactions in these mixtures. It was found that the strength of interaction between [BMIm][BF4] with the studied organic solvents has the order DMSO > DMA > MeOH > MeCN > THF.

Reactions of Lignin Model Compounds in Ionic Liquids

Energy Technology Data Exchange (ETDEWEB)

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

2009-09-15

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

Ionic liquids at the surface of graphite: Wettability and structure

Science.gov (United States)

Bordes, Emilie; Douce, Laurent; Quitevis, Edward L.; Pádua, Agílio A. H.; Costa Gomes, Margarida

2018-05-01

The aim of this work is to provide a better understanding of the interface between graphite and different molecular and ionic liquids. Experimental measurements of the liquid surface tension and of the graphite-liquid contact angle for sixteen ionic liquids and three molecular liquids are reported. These experimental values allowed the calculation of the solid/liquid interfacial energy that varies, for the ionic liquids studied, between 14.5 mN m-1 for 1-ethyl-3-methylimidazolium dicyanamide and 37.8 mN m-1 for 3-dodecyl-1-(naphthalen-1-yl)-1H-imidazol-3-ium tetrafluoroborate. Imidazolium-based ionic liquids with large alkyl side-chains or functionalized with benzyl groups seem to interact more favourably with freshly peeled graphite surfaces. Even if the interfacial energy seems a good descriptor to assess the affinity of a liquid for a carbon-based solid material, we conclude that both the surface tension of the liquid and the contact angle between the liquid and the solid can be significant. Molecular dynamics simulations were used to investigate the ordering of the ions near the graphite surface. We conclude that the presence of large alkyl side-chains in the cations increases the ordering of ions at the graphite surface. Benzyl functional groups in the cations lead to a large affinity towards the graphite surface.

Biochemical and genetic toxicity of the ionic liquid 1-octyl-3-methylimidazolium chloride on earthworms (Eisenia fetida).

Science.gov (United States)

Guo, Yingying; Liu, Tong; Zhang, Jun; Wang, Jinhua; Wang, Jun; Zhu, Lusheng; Yang, Jinhui

2016-02-01

Ionic liquids also known as "green solvents," are used in many fields. However, the dispersion of ionic liquids in soil systems is likely to cause damage to soil organisms. The objective of the present study was to investigate the toxicity of 1-octyl-3-methylimidazolium chloride ([C8 mim]Cl) on earthworms (Eisenia fetida). For this purpose, earthworms were exposed to different concentrations of [C8 mim]Cl (0 mg/kg, 5 mg/kg, 10 mg/kg, 20 mg/kg, and 40 mg/kg artificial soil) and sampled at 7 d, 14 d, 21 d, and 28 d. The results indicated that [C8 mim]Cl could cause an accumulation of reactive oxygen species (ROS) in earthworms, even at the lowest concentration (5 mg/kg). Compared with the controls, during the [C8 mim]Cl exposure period, the activities of superoxide dismutase (SOD) and catalase (CAT) decreased and then increased, whereas the activities of peroxidase (POD) and glutathione S-transferase (GST) increased. These changes in the activities of antioxidant enzymes and GST indicated that [C8 mim]Cl could induce oxidative damage in earthworms. The malondialdehyde content was increased by high levels of [C8 mim]Cl at 14 d and 28 d, indicating that [C8 mim]Cl could lead to lipid peroxidation in earthworms. In addition, the degree of DNA damage significantly increased with increasing [C8 mim]Cl concentrations and exposure time. The present study shows that [C8 mim]Cl caused biochemical and genetic toxicity in earthworms. © 2015 SETAC.

Investigations of 1-(4-propylamino-3-ethyl imidazolium tetrafluoroborate ionic liquid capturing CO2

Directory of Open Access Journals (Sweden)

Yang Lijuan

2013-01-01

Full Text Available 1-(4-propylamino-3-ethyl imidazolium ([Paeim]+ Tetrafluoroborate([BF4]- Ionic liquid (IL, capturing CO2, was explored systematically at B3LYP/6-311++G** and mp2/6-311++G** level. The stable geometries of ILs and capture products were optimized, the energies of these geometries were obtained and corrected by Zero-point-vibration-energy and basis set superposition error correction. The results show that the interactions between [Paeim]+and [BF4]-are mainly displayed as hydrogen bonds, but the interaction energies exceeds -328 kJ/mol. Further analysis found that the interactions are reinforced by charge dispersion and charge redistribution of ion-pair, and that electrostatic attraction contributes much to the interaction energies. This IL system capturing CO2belongs to the class of physical sorption with 1:1 molar absorption ratio, the absorption energy is nearly -18kJ/moland thus this IL may have low energy consumption when regenerated from IL-CO2.

Synthesis, characterization and application of 1-butyl-3-methylimidazolium tetrafluoroborate for extractive desulfurization of liquid fuel

Directory of Open Access Journals (Sweden)

Swapnil A. Dharaskar

2016-07-01

Full Text Available In the present paper the experimental data of extractive desulfurization of liquid fuel using 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM]BF4 have been presented. The data of FTIR, 1H NMR and 13C NMR have been discussed for the molecular confirmation of synthesized [BMIM]BF4. Further, the thermal properties, conductivity, solubility, and viscosity analysis of the [BMIM]BF4 were carried out. The effects of reaction time, reaction temperature, sulfur compounds, and recycling of ionic liquid without regeneration on dibenzothiophene removal of liquid fuel were presented. In extractive desulfurization process, the removal of dibenzothiophene in n-dodecane was 73.02% for mass ratio of 1:1 in 30 min at 30 °C under the mild reaction conditions. The ionic liquids could be reused four times without a significant decrease in activity. Also, the desulfurizations of real fuels, multistage extraction were presented. The data and results provided in the present paper explore the significant insights of imidazoled ILs for extractive desulfurization of liquid fuels.

Experimental Discovery of Magnetoresistance and Its Memory Effect in Methylimidazolium-Type Iron-Containing Ionic Liquids

KAUST Repository

Zhang, Haitao; Zhang, Suojiang; Zhang, Xixiang

2016-01-01

carriers. Here, we report the observation of positive magnetoresistance and its memory effect in methylimidazolium-type iron-containing ionic liquids (ILs). Both the electrical transport and magnetic properties of ILs were measured to understand

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)

Ghasemian, Ensieh; Najafi, Mojgan; Rafati, Amir Abbas; Felegari, Zahra

2010-01-01

Surface and bulk properties of 1-hexyl-3-methylimidazolium chloride [C 6 mim][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 (A min ) 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 [C 6 mim][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.

High-performance supercapacitors based on poly(ionic liquid)-modified graphene electrodes.

Science.gov (United States)

Kim, Tae Young; Lee, Hyun Wook; Stoller, Meryl; Dreyer, Daniel R; Bielawski, Christopher W; Ruoff, Rodney S; Suh, Kwang S

2011-01-25

We report a high-performance supercapacitor incorporating a poly(ionic liquid)-modified reduced graphene oxide (PIL:RG-O) electrode and an ionic liquid (IL) electrolyte (specifically, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide or EMIM-NTf(2)). PIL:RG-O provides enhanced compatibility with the IL electrolyte, thereby increasing the effective electrode surface area accessible to electrolyte ions. The supercapacitor assembled with PIL:RG-O electrode and EMIM-NTf(2) electrolyte showed a stable electrochemical response up to 3.5 V operating voltage and was capable of yielding a maximum energy density of 6.5 W·h/kg with a power density of 2.4 kW/kg. These results demonstrate the potential of the PIL:RG-O material as an electrode in high-performance supercapacitors.

Dissolution of cellulose in ionic liquid: A review

Science.gov (United States)

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

2017-02-01

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

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

International Nuclear Information System (INIS)

Baker, Gary A.; Heller, William T.

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

Antiwear performance of ionic liquid+graphene dispersions with anomalous viscosity-temperature behavior

OpenAIRE

Pamies Porras, Ramón Francisco; Arias Pardilla, Joaquín; Espinosa Rodríguez, Tulia; Carrión Vilches, Francisco José; Bermúdez Olivares, María Dolores; Sanes Molina, José; Avilés González, María Dolores

2018-01-01

New dispersions of few-layers graphene (G) in 1-ethyl-3-methylimidazolium ([EMIM]) ionic liquids (ILs) with dicyanamide ([DCA]) or bis(trifluoromethylsulfonyl)imide ([TFSI]) anions have been obtained by mechanical mixing and sonication. IL+0.5 wt% G dispersions show constant viscosity values from 357K (for IL = [EMIM][DCA]) or from 385K (for IL = [EMIM][TFSI]) to 393K. IL + G dispersions with G > 0.5 wt% show linear viscosity increases with increasing temperature, from 306K (for [EMIM][DCA]+1...

Physically and chemically stable ionic liquid-infused textured surfaces showing excellent dynamic omniphobicity

Energy Technology Data Exchange (ETDEWEB)

Miranda, Daniel F.; Urata, Chihiro; Masheder, Benjamin; Dunderdale, Gary J.; Hozumi, Atsushi, E-mail: a.hozumi@aist.go.jp [National Institute of Advanced Industrial Science and Technology (AIST), 2266-98, Anagahora, Shimo-Shidami, Moriyama-ku, Nagoya, Aichi 463-8560 (Japan); Yagihashi, Makoto [Nagoya Municipal Industrial Research Institute, Rokuban, Atsuta-ku, Nagoya 456-0058 (Japan)

2014-05-01

A fluorinated and hydrophobic ionic liquid (IL), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide, effectively served as an advantageous lubricating liquid for the preparation of physically and chemically stable omniphobic surfaces based on slippery liquid-infused porous surfaces. Here, we used particulate microstructures as supports, prepared by the chemical vapor deposition of 1,3,5,7-tetramethylcyclotetrasiloxane and subsequent surface modification with (3-aminopropyl)triethoxysilane. Confirmed by SEM and contact angle measurements, the resulting IL-infused microtextured surfaces are smooth and not only water but also various low surface tension liquids can easily slide off at low substrate tilt angles of <5°, even after exposure to high temperature, vacuum, and UV irradiation.

Physically and chemically stable ionic liquid-infused textured surfaces showing excellent dynamic omniphobicity

Directory of Open Access Journals (Sweden)

Daniel F. Miranda

2014-05-01

Full Text Available A fluorinated and hydrophobic ionic liquid (IL, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl imide, effectively served as an advantageous lubricating liquid for the preparation of physically and chemically stable omniphobic surfaces based on slippery liquid-infused porous surfaces. Here, we used particulate microstructures as supports, prepared by the chemical vapor deposition of 1,3,5,7-tetramethylcyclotetrasiloxane and subsequent surface modification with (3-aminopropyltriethoxysilane. Confirmed by SEM and contact angle measurements, the resulting IL-infused microtextured surfaces are smooth and not only water but also various low surface tension liquids can easily slide off at low substrate tilt angles of <5°, even after exposure to high temperature, vacuum, and UV irradiation.

Polyethersulfone flat sheet and hollow fiber membranes from solutions in ionic liquids

KAUST Repository

Kim, Dooli

2017-06-10

We fabricated flat-sheet and hollow fiber membranes from polyethersulfone (PES) solutions in two ionic liquids: 1-ethyl-3-methylimidazolium diethyl phosphate ([EMIM]DEP) and 1,3-dimethylimidazolium dimethyl phosphate ([MMIM]DMP). The solvents are non-volatile and less toxic than organic solvents, such as dimethylformamide (DMF). The membranes morphologies were compared with those of membranes prepared from solutions in DMF, using electron microscopy. Water permeance, solute rejection and mechanical strengths were evaluated. Membranes were applied to DNA separation. While membranes based on PES were successfully prepared, polysulfone (PSf) does not dissolve in the same ionic liquids. The discrepancy between PES and PSf could not be explained using classical Flory-Huggins theory, which does not consider the coulombic contributions in ionic liquids. The differences in solubility could be understood, by applying density functional theory to estimate the interaction energy between the different polymers and solvents. The theoretical results were supported by experimental measurements of intrinsic viscosity and dynamic light scattering (DLS).

Evaporation Study of an Ionic Liquid with a Double-Charged Cation.

Science.gov (United States)

Chilingarov, Norbert S; Zhirov, Maksim S; Shmykova, Anna M; Martynova, Ekaterina A; Glukhov, Lev M; Chernikova, Elena A; Kustov, Leonid M; Markov, Vitaliy Yu; Ioutsi, Vitaliy A; Sidorov, Lev N

2018-05-07

The evaporation of a dicationic ionic liquid, 1,3-bis(3-methylimidazolium-1-yl)propane bis(trifluoromethanesulfonyl)amide ([C 3 (MIm) 2 2+ ][Tf 2 N - ] 2 ), was studied by Knudsen effusion mass spectrometry. Its evaporation is accompanied by a partial thermal decomposition producing monocationic ionic liquids, 1,3-dimethylimidazolium and 1-(2-propenyl)-3-methylimidazolium bis(trifluoromethanesulfonyl)amides, as volatile products. This decomposition does not affect the vaporization characteristics of [C 3 (MIm) 2 2+ ][Tf 2 N - ] 2 , which were established to be as follows. The vaporization enthalpy (550 K) is equal to (155.5 ± 3.2) kJ·mol -1 ; the saturated vapor pressure is described by the equation ln( p/Pa) = -(18699 ± 381)/( T/K) + (30.21 ± 0.82) in the range of 508-583 K. 1,3-Bis(3-methylimidazolium-1-yl)propane bis(trifluoromethanesulfonyl)amide is the first dicationic ionic liquid, the vaporization characteristics of which were determined with an acceptable accuracy.

Ionic conductivity studies of gel polyelectrolyte based on ionic liquid

Energy Technology Data Exchange (ETDEWEB)

Cha, E.H. [The Faculty of Liberal Arts (Chemistry), Hoseo University, Asan Choongnam 336-795 (Korea); Lim, S.A. [Functional Proteomics Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea); Park, J.H. [Department of Herbal Medicine, Hoseo University, Asan Choongnam 336-795 (Korea); Kim, D.W. [Department of Chemical Technology, Han Bat National University, Daejon 305-719 (Korea); Macfarlane, D.R. [School of Chemistry, Monash University, Clayton, Vic. 3800 (Australia)

2008-04-01

Novel lithium polyelectrolyte-ionic liquids have been prepared and characterized of their properties. Poly(lithium 2-acrylamido-2-methyl propanesulfonate) (PAMPSLi) and its copolymer with N-vinyl formamide (VF) also has been prepared as a copolymer. 1-Ethyl-3-methylimidazolium tricyanomethanide (emImTCM) and N,N-dimethyl-N-propyl-N-butyl ammonium tricyanomethanide (N{sub 1134}TCM) which are chosen because of the same with the anion of ionic liquid were prepared. The ionic conductivity of copolymer system (PAMPSLi/PVF/emImTCM: 5.43 x 10{sup -3} S cm{sup -1} at 25 C) exhibits about over four times higher than that of homopolymer system (PAMPSLi/emImTCM: 1.28 x 10{sup -3} S cm{sup -1} at 25 C). Introduction of vinyl formamide into the copolymer type can increase the dissociation of the lithium cations from the polymer backbone. The ionic conductivity of copolymer with emImTCM (PAMPSLi/PVF/emImTCM) exhibits the higher conductivity than that of PAMPSLi/PVF/N{sub 1134}TCM (2.48 x 10{sup -3} S cm{sup -1}). Because of using the polymerizable anion it is seen to maintain high flexibility of imidazolium cation effectively to exhibit the higher conductivity. And also the viscosity of emImTCM (19.56 cP) is lower than that of N{sub 1134}TCM (28.61 cP). Low viscosity leads to a fast rate of diffusion of redox species. (author)

CO₂ Capture and Separation Properties in the Ionic Liquid 1-n-Butyl-3-Methylimidazolium Nonafluorobutylsulfonate.

Science.gov (United States)

Zhou, Lingyun; Fan, Jing; Shang, Xiaomin

2014-05-14

Recently, the use of ionic liquids (ILs) for carbon capture and separation processes has gained great interest by many researchers due to the high solubility of CO₂ in ILs. In the present work, solubility measurements of CO₂ in the novel IL 1-n-butyl-3-methylimidazolium nonafluorobutylsulfonate [C₄mim][CF₃CF₂CF₂CF₂SO₃] were performed with a high-pressure view-cell technique in the temperature range from 293.15 to 343.15 K and pressures up to about 4.2 MPa. For comparison, solubilities of H₂, N₂, and O₂ in the IL were also measured at 323.15 K via the same procedure. The Krichevsky-Kasarnovsky equation was employed to correlate the measured solubility data. Henry's law constants, enthalpies, and entropies of absorption for CO₂ in the IL were also determined and presented. The CO₂ solubility in this IL was compared with other ILs sharing the same cation. It was shown that the solubility of CO₂ in these ILs follows the sequence: [C₄mim][CF₃CF₂CF₂CF₂SO₃] ≈ [C₄mim][Tf₂N] > [C₄mim][CF₃CF₂CF₂COO] > [C₄mim][BF₄], and the solubility selectivity of CO₂ relative to O₂, N₂, and H₂ in [C₄mim][CF₃CF₂CF₂CF₂SO₃] was 8, 16, and 22, respectively. Furthermore, this IL is regenerable and exhibits good stability. Therefore, the IL reported here would be a promising sorbent for CO₂.

The effect of water on the microstructure of 1-butyl-3-methylimidazolium tetrafluoroborate/TX-100/benzene ionic liquid microemulsions.

Science.gov (United States)

Gao, Yan'an; Li, Na; Zheng, Liqiang; Zhao, Xueyan; Zhang, Jin; Cao, Quan; Zhao, Mingwei; Li, Zhen; Zhang, Gaoyong

2007-01-01

The ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) forms nonaqueous microemulsions with benzene with the aid of nonionic surfactant TX-100. The phase diagram of the ternary system was prepared, and the microstructures of the microemulsion were recognized. On the basis of the phase diagram, a series of ionic liquid-in-oil (IL/O) microemulsions were chosen and characterized by dynamic light scattering (DLS), which shows a similar swelling behavior to typical water-in-oil (W/O) microemulsions. The existence of IL pools in the IL/O microemulsion was confirmed by UV/Vis spectroscopic analysis with CoCl2 and methylene blue (MB) as the absorption probes. A constant polarity of the IL pool is observed, even if small amounts of water are added to the microemulsion, thus suggesting that the water molecules are solubilized in the polar outer shell of the microemulsion, as confirmed by FTIR spectra. 1H NMR spectroscopic analysis shows that these water molecules interact with the electronegative oxygen atoms of the oxyethylene (OE) units of TX-100 through hydrogen-bonding interactions, and the electronegative oxygen atoms of the water molecules attract the electropositive imidazolium rings of [bmim][BF4]. Hence, the water molecules are like a glue that stick the IL and OE units more tightly together and thus make the microemulsion system more stable. Considering the unique solubilization behavior of added water molecules, the IL/O microemulsion system may be used as a medium to prepare porous or hollow nanomaterials by hydrolysis reactions.

Extraction of toluene from aliphatic compounds using an ionic liquid as solvent: Influence of the alkane on the (liquid + liquid) equilibrium

International Nuclear Information System (INIS)

Gonzalez, Emilio J.; Calvar, Noelia; Dominguez, Irene; Dominguez, Angeles

2011-01-01

Research highlights: → An ionic liquid was analyzed as solvent for extraction of toluene from alkanes. → Liquid-liquid equilibrium data were measured at 298.15 K and atmospheric pressure. → Selectivity and solute distribution ratio were obtained and compared with literature. → The Othmer-Tobias equation was used to ascertain the experimental LLE data. → Experimental data were correlated using NRTL and UNIQUAC models. - Abstract: In this paper, the feasibility of using 1-ethyl-3-methylimidazolium ethylsulfate ionic liquid, [EMim][ESO 4 ], as solvent for the extraction of toluene from aliphatic compounds (hexane, heptane, octane, or nonane) was analyzed. (Liquid + liquid) equilibrium (LLE) data for the ternary systems {alkane (1) + toluene (2) + [EMim][ESO 4 ] (3)} were measured at T = 298.15 K and atmospheric pressure. Selectivity and solute distribution ratio were calculated from the experimental LLE data, and the obtained values were compared to those previously reported using other ionic liquids and sulfolane. The degree of consistency of the experimental LLE data was ascertained using the Othmer-Tobias equation. Finally, the experimental LLE data were satisfactorily correlated with NRTL and UNIQUAC models.

Multi-scale processes of beech wood disintegration and pretreatment with 1-ethyl-3-methylimidazolium acetate/water mixtures.

Science.gov (United States)

Viell, Jörn; Inouye, Hideyo; Szekely, Noemi K; Frielinghaus, Henrich; Marks, Caroline; Wang, Yumei; Anders, Nico; Spiess, Antje C; Makowski, Lee

2016-01-01

The valorization of biomass for chemicals and fuels requires efficient pretreatment. One effective strategy involves the pretreatment with ionic liquids which enables enzymatic saccharification of wood within a few hours under mild conditions. This pretreatment strategy is, however, limited by water and the ionic liquids are rather expensive. The scarce understanding of the involved effects, however, challenges the design of alternative pretreatment concepts. This work investigates the multi length-scale effects of pretreatment of wood in 1-ethyl-3-methylimidazolium acetate (EMIMAc) in mixtures with water using spectroscopy, X-ray and neutron scattering. The structure of beech wood is disintegrated in EMIMAc/water mixtures with a water content up to 8.6 wt%. Above 10.7 wt%, the pretreated wood is not disintegrated, but still much better digested enzymatically compared to native wood. In both regimes, component analysis of the solid after pretreatment shows an extraction of few percent of lignin and hemicellulose. In concentrated EMIMAc, xylan is extracted more efficiently and lignin is defunctionalized. Corresponding to the disintegration at macroscopic scale, SANS and XRD show isotropy and a loss of crystallinity in the pretreated wood, but without distinct reflections of type II cellulose. Hence, the microfibril assembly is decrystallized into rather amorphous cellulose within the cell wall. The molecular and structural changes elucidate the processes of wood pretreatment in EMIMAc/water mixtures. In the aqueous regime with >10.7 wt% water in EMIMAc, xyloglucan and lignin moieties are extracted, which leads to coalescence of fibrillary cellulose structures. Dilute EMIMAc/water mixtures thus resemble established aqueous pretreatment concepts. In concentrated EMIMAc, the swelling due to decrystallinization of cellulose, dissolution of cross-linking xylan, and defunctionalization of lignin releases the mechanical stress to result in macroscopic disintegration of

Full characterization of polypyrrole thin films electrosynthesized in room temperature ionic liquids, water or acetonitrile

International Nuclear Information System (INIS)

Viau, L.; Hihn, J.Y.; Lakard, S.; Moutarlier, V.; Flaud, V.; Lakard, B.

2014-01-01

Highlights: • Polypyrrole films were electrodeposited from three room temperature ionic liquids. • Polymer films were characterized using many surface analysis techniques. • The incorporation of anions and/or cations inside the polymer films was evidenced. • The influence of the ionic liquid on the polymer properties was deeply studied. - Abstract: Pyrrole was electrochemically oxidized in two conventional media (water and acetonitrile) and in three room temperature ionic liquids: 1-butyl-3-methylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, and 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide. Infrared and Raman Spectroscopies confirmed the formation of polypyrrole by electropolymerization but were unable to demonstrate the presence of anions in the polymer films. The use of ionic liquids as growth media resulted in polymer films having a good electrochemical activity. The difference of activity from one polymer film to the other was mainly attributed to the difference of viscosity between the solvents used. The morphological features of the polypyrrole films were also fully studied. Profilometric measurements demonstrated that polymer films grown, at the same potential, in ionic liquids were thinner and had a smaller roughness than those grown in other solvents. Atomic Force Microscopy showed that polypyrrole films had nearly similar micrometric nodular structure whatever the growth medium even if some differences of porosity and homogeneity were observed using Scanning Electron Microscopy. The incorporation of counter-anions at the top surface of the films was finally evidenced by X-ray Photoelectron Spectroscopy. These anions were also incorporated inside the polymer film with a uniform distribution as shown by Glow Discharge Optical Emission Spectroscopy

Application and recovery of ionic liquids in the preparative separation of four flavonoids from Rhodiola rosea by on-line three-dimensional liquid chromatography.

Science.gov (United States)

Ma, Shufeng; Hu, Liming; Ma, Chaoyang; Lv, Wenping; Wang, Hongxin

2014-09-01

A novel on-line three-dimensional liquid chromatography method was developed to separate four main flavonoids from Rhodiola rosea. Ethyl acetate/0.5 mol/L ionic liquid 1-butyl-3-methylimidazolium chloride aqueous solution was selected as the solvent system. In the first-dimension separation, the target flavonoids were entrapped and subsequently desorbed into the second-dimension high-speed countercurrent chromatographic column for separation. In the third-dimension chromatography, the residual ionic liquid in the four separated flavonoids was removed and the used ionic liquid was recovered. As a result, 35.1 mg of compound 1, 20.4 mg of compound 2, 8.5 mg of compound 3, and 10.6 mg of compound 4 were obtained from 1.53 g R. rosea extract. They were identified as rhodiosin, rhodionin, herbacetin, and kaempferol, respectively. The recovery of ionic liquid reached 99.1% of the initial amount. The results showed that this method is a powerful technology for the separation of R. rosea flavonoids and that the ionic-liquid-based solvent system has advantages over traditional solvent systems in renewable and environmentally friendly properties. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Application of Prigogine-Flory-Patterson theory to excess molar volume of mixtures of 1-butyl-3-methylimidazolium ionic liquids with N-methyl-2-pyrrolidinone

International Nuclear Information System (INIS)

Qi Feng; Wang Haijun

2009-01-01

The densities of two binary mixtures formed by 1-butyl-3-methylimidazolium tetrafluoroborate [bmim][BF 4 ] and 1-butyl-3-methy limidazolium hexafluorophosphate [bmim][PF 6 ] with compound N-methyl-2-pyrrolidinone have been determined over the full range of composition and range of temperature from (298.15 to 313.15) K and at atmospheric pressure using a vibrating-tube densimeter (DMA4500). Excess molar volumes, V m E , have been obtained from these experimental results, and been fitted by the fourth-order Redlich-Kister equation. From the experimental results, partial molar volumes, apparent molar volume and partial molar volumes at infinite dilution were calculated over the whole composition range. Our results show that V m E decreases slightly when temperature increases in the systems studied. The experimental results have been used to test the applicability of the Prigogine-Flory-Patterson (PFP) theory. The results have been interpreted in terms of ion-dipole interactions and structural factors of the ionic liquid and these organic molecular liquids

Tb3+ and Eu3+ luminescence in imidazolium ionic liquids

International Nuclear Information System (INIS)

Hopkins, Todd; Goldey, Matt

2009-01-01

The luminescence properties of Tb 3+ and Eu 3+ dissolved in ionic liquids are studied. Solutes in this study include simple lanthanide compounds (e.g., EuBr 3 , TbCl 3 ) and lanthanide complexes (e.g., Eu(dpa) 3 3- where dpa = 2,6 pyridine dicarboxylate dianion) dissolved in a 1-butyl-3-methylimidazolium bromide(BMIBr)/water mixture. Emission, excitation, and time-resolved emission measurements are utilized to characterize the spectroscopic properties. It is well established in the literature that the solubility and spectroscopic properties of lanthanides in ionic liquids are highly dependent upon environmental factors including purity, and water content [K. Binnemans, Chemical Reviews (2007); I. Billard, S. Mekki, C. Gaillard, P. Hesemann, C. Mariet, G. Moutiers, A. Labet, J.-C.G. Buenzli, European Journal of Inorganic Chemistry 6 (2004) 1190-1197; S. Samikkanu, K. Mellem, M. Berry, P.S. May, Inorganic Chemistry 46 (2007) 7121-7128]. The water in this ionic liquid system acts as a co-solvent to facilitate solubility of Tb 3+ and Eu 3+ compounds. The observed spectroscopic properties of Eu 3+ and Tb 3+ salts are expectedly impacted by the high water content, but unexpectedly impacted by the BMIBr ionic liquid. However, the spectroscopy of Eu(dpa) 3 3- is unaffected by the presence of BMIBr.

Preparation and properties of titania based ionogels synthesized using ionic liquid 1-ethyl-3-methyl imidazolium thiocyanate

Energy Technology Data Exchange (ETDEWEB)

Verma, Y.L.; Tripathi, A.K.; Shalu; Singh, V.K.; Balo, L.; Gupta, H.; Singh, S.K.; Singh, R.K., E-mail: rajendrasingh.bhu@gmail.com

2017-06-15

Highlights: • Synthesis of titania based ionogels using non-aqueous sol-gel process. • Ionogels are found to be mesoporous structure with uniform pore size distribution. • Ionic liquid extracted TiO{sub 2} matrix reveals the anatase phase of TiO{sub 2}. • Properties of ionic liquid are found to change in TiO{sub 2} matrix. - Abstract: Present study reports the synthesis of titania (TiO{sub 2}) based ionogels using ionic liquid (IL) 1-ethyl-3-methyl imidazolium thiocyanate ([EMIM][SCN]) by non-aqueous sol-gel process. Ionogels are characterized using N{sub 2} adsorption-desorption, TGA, DSC, SEM, TEM, XRD, and FTIR. N{sub 2}-sorption results show that TiO{sub 2} matrices have meso-pores with uniform pore size distribution. Thermal studies reveal that thermal stability of confined IL decreases while the glass transition temperature (T{sub g}) is found to increase. XRD patterns show that IL containing TiO{sub 2} matrices exhibit amorphous (weak crystalline peaks) nature however after extraction of IL from ionogel, it shows the crystalline (anatase) phase of TiO{sub 2} which has also been found from SAED pattern. SEM micrographs reveal that as the amount of IL is increased, TiO{sub 2} particles are found to agglomerate. FTIR results indicate that the vibrational frequencies of confined IL are found to shift due to interaction of IL molecules with titania pore wall surface.

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

Science.gov (United States)

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

2015-04-01

In this study, microbial communities from chemicals polluted microhabitats were cultured with the addition of imidazolium-based ionic liquid (IL) to enrich for IL-tolerant microbes. A strain of Fusarium oxysporum BN producing cellulase from these enrichments was capable of growing in 10% (w/v) 1-ethyl-3-methylimidazolium phosphinate, much higher than the normal IL concentrations in the lignocellulose regenerated from ILs. Cellulase secreted by the strain showed high resistance to ILs based on phosphate and sulfate radicals, evidencing of a high conformational stability in relevant media. Gratifyingly, F. oxysporum BN can directly convert IL-pretreated rice straw to bioethanol via consolidated bioprocessing (I-CBP). At optimum fermentation condition, a maximum ethanol yield of 0.125 g ethanol g(-1) of rice straw was finally obtained, corresponding to 64.2% of the theoretical yield. Copyright © 2015 Elsevier Ltd. All rights reserved.

Evaluation of thermophysical properties of ionic liquids with polar solvent: a comparable study of two families of ionic liquids with various ions.

Science.gov (United States)

Govinda, Varadhi; Attri, Pankaj; Venkatesu, Punnuru; Venkateswarlu, Ponneri

2013-10-17

In this work, we explore and compare the role of the ion effect on the thermophysical properties of two families of ionic liquids (ILs), namely, tetra-alkyl ammonium cation [R4N](+) with hydroxide [OH](-) anion and 1-alkyl-3-methyl imidazolium cation [amim](+) with different anions (chloride, methyl sulfate, and tetrafluoroborate), with polar solvent such as dimethylsulfoxide (DMSO) in the temperature range from 25 to 40 °C and over the whole concentration range of ILs. Two families of ILs, namely, tetramethyl ammonium hydroxide [(CH3)4N][OH] (TMAH), tetraethyl ammonium hydroxide [(C2H5)4N][OH] (TEAH), tetrapropyl ammonium hydroxide [(C3H7)4N][OH] (TPAH), and tetrabutyl ammonium hydroxide [(C4H9)4N][OH] (TBAH) from ammonium-based ILs and 1-ethyl-3-methylimidazolium chloride [Emim][Cl], 1-ethyl-3-methylimidazolium methylsulfate [Emim][MeSO4], 1-butyl-3-methylimidazolium tetrafluoroborate [Bmim][BF4], and 1-butyl-3-methylimidazolium chloride ([Bmim][Cl]) from imidazolium family of ILs, are used in the present study. To address the molecular interactions of ILs with DMSO, densities (ρ), ultrasonic sound velocities (u), and viscosities (η) have been measured over the entire composition range and at four temperatures, 25, 30, 35, and 40 °C, under atmospheric pressure. From these experimental data, the excess molar volume (V(E)), the deviation in isentropic compressibility (Δκs), and the deviation in viscosity (Δη) were calculated and were adequately correlated by using the Redlich-Kister polynomial equation. The measured and predicted data were interpreted on the basis of intermolecular interactions and structural effects between like and unlike molecules upon mixing. The hydrogen-bonding features between ammonium-based ILs and DMSO were analyzed using molecular modeling program by HyperChem 7.

Effect of alkyl chain length on the rotational diffusion of nonpolar and ionic solutes in 1-alkyl-3-methylimidazolium-bis(trifluoromethylsulfonyl)imides.

Science.gov (United States)

Gangamallaiah, V; Dutt, G B

2013-10-10

Rotational diffusion of a nonpolar solute 9-phenylanthracene (9-PA) and a cationic solute rhodamine 110 (R110) has been examined in a series of 1-alkyl-3-methylimidazolium (alkyl = octyl, decyl, dodecyl, tetradecyl, hexadecyl, and octadecyl) bis(trifluoromethylsulfonyl)imides to understand the influence of alkyl chain length on solute rotation. In this study, reorientation times (τr) have been measured as a function of viscosity (η) by varying the temperature (T) of the solvents. These results have been analyzed using the Stokes-Einstein-Debye (SED) hydrodynamic theory along with the ones obtained for the same solutes in 1-alkyl-3-methylimidazolium (alkyl = methyl, ethyl, propyl, butyl, and hexyl) bis(trifluoromethylsulfonyl)imides (Gangamallaiah and Dutt, J. Phys. Chem. B 2012, 116, 12819-12825). It has been noticed that the data for 9-PA and R110 follows the relation τr = A(η/T)(n) with A being the ratio of hydrodynamic volume of the solute to the Boltzmann constant and n = 1 as envisaged by the SED theory. However, upon increasing the alkyl chain length from methyl to octadecyl significant deviations from the SED theory have been observed especially from the octyl derivative onward. From methyl to octadecyl derivatives, the value of A decreases by a factor of 3 for both the solutes and n by a factor of 1.4 and 1.6 for 9-PA and R110, respectively. These observations have been rationalized by taking into consideration the organized structure of the ionic liquids, whose influence appears to be pronounced when the number of carbon atoms in the alkyl chain attached to the imidazolium cation exceeds eight.

Activity coefficients at infinite dilution and physicochemical properties for organic solutes and water in the ionic liquid 1-(2-hydroxyethyl)-3-methylimidazolium trifluorotris(perfluoroethyl)phosphate

International Nuclear Information System (INIS)

Marciniak, Andrzej; Wlazło, Michał

2013-01-01

Highlights: • γ ∞ and K L for 65 solutes in the IL [C 2 OHmim][FAP] were determined by IGC. • Partial molar thermodynamics functions ΔG 1 E,∞ , ΔH 1 E,∞ and ΔS 1 E,∞ were calculated. • Selectivities and capacities for alkanes/thiophene separation problems were calculated. • LFER system constants as a function of T for [C 2 OHmim][FAP] were calculated. • Results were compared to other ILs based on the same cation and anion. -- Abstract: This work presents new data of activity coefficients at infinite dilution, γ ∞ of different organic solutes and water in the 1-(2-hydroxyethyl)-3-methylimidazolium trifluorotris(perfluoroethyl)phosphate, [C 2 OHmim][FAP] ionic liquid. Values of γ ∞ were determined for 65 organic solutes, including alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, thiophene, ethers, ketones, esters, 1-nitropropane, aldehydes, acetonitrile and water by inverse gas chromatography within the temperature range from (318.15 to 368.15) K. The basic thermodynamic functions, such as partial molar excess Gibbs energies, ΔG 1 E,∞ , enthalpies, ΔH 1 E,∞ and entropies, ΔS 1 E,∞ at infinite dilution were calculated from the experimental γ ∞ values obtained over the temperature range. Additionally the gas–liquid partition coefficients, K L were determined. Experimental values of gas–liquid partition coefficients were used to determine the coefficients in the Abraham solvation parameter model (LFER). Results are compared to previously investigated ionic liquids with the same [C 2 OHmim] + cation and [FAP] − anion. The selectivity and capacity at infinite dilution for alkanes/thiophene extraction problems were calculated from experimental γ ∞ values to verify the possibility of investigated ionic liquid as an entrainer in liquid–liquid extraction

Ideal gas solubilities and solubility selectivities in a binary mixture of room-temperature ionic liquids.

Science.gov (United States)

Finotello, Alexia; Bara, Jason E; Narayan, Suguna; Camper, Dean; Noble, Richard D

2008-02-28

This study focuses on the solubility behaviors of CO2, CH4, and N2 gases in binary mixtures of imidazolium-based room-temperature ionic liquids (RTILs) using 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C2mim][Tf2N]) and 1-ethyl-3-methylimidazolium tetrafluoroborate ([C2mim][BF4]) at 40 degrees C and low pressures (approximately 1 atm). The mixtures tested were 0, 25, 50, 75, 90, 95, and 100 mol % [C2mim][BF4] in [C2mim][Tf2N]. Results show that regular solution theory (RST) can be used to describe the gas solubility and selectivity behaviors in RTIL mixtures using an average mixture solubility parameter or an average measured mixture molar volume. Interestingly, the solubility selectivity, defined as the ratio of gas mole fractions in the RTIL mixture, of CO2 with N2 or CH4 in pure [C2mim][BF4] can be enhanced by adding 5 mol % [C2mim][Tf2N].

Aerobic, catalytic oxidation of alcohols in ionic liquids

Directory of Open Access Journals (Sweden)

Souza Roberto F. de

2006-01-01

Full Text Available An efficient and simple catalytic system based on RuCl3 dissolved in ionic liquids has been developed for the oxidation of alcohols into aldehydes and ketones under mild conditions. A new fluorinated ionic liquid, 1-n-butyl-3-methylimidazolium pentadecafluorooctanoate, was synthesized and demonstrated better performance that the other ionic liquids employed. Moreover this catalytic system utilizes molecular oxygen as an oxidizing agent, producing water as the only by-product.

Electrochemical properties of novel ionic liquids for electric double layer capacitor applications

International Nuclear Information System (INIS)

Sato, Takaya; Masuda, Gen; Takagi, Kentaro

2004-01-01

An aliphatic quaternary ammonium salt which has a methoxyethyl group on the nitrogen atom formed an ionic liquid (room temperature molten salt) when combined with the tetrafluoroborate (BF 4 - ) and bis(trifluoromethylsulfonyl)imide [TFSI; (CF 3 SO 2 ) 2 N - ] anions. The limiting oxidation and reduction potentials, specific conductivity, and some other physicochemical properties of the novel ionic liquids, N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium tetrafluoroborate (DEME-BF 4 ) and DEME-TFSI have been evaluated and compared with those of 1-ethyl-3-methylimidazolium tetrafluoroborate. DEME-BF 4 is a practically useful ionic liquid for electrochemical capacitors as it has a quite wide potential window (6.0 V) and high ionic conductivity (4.8 mS cm -1 at 25 deg. C). We prepared an electric double layer capacitor (EDLC) composed of a pair of activated carbon electrodes and DEME-BF 4 as the electrolyte. This EDLC (working voltage ∼2.5 V) has both, a higher capacity above room temperature and a better charge-discharge cycle durability at 100 deg. C when compared to a conventional EDLC using an organic liquid electrolyte such as a tetraethylammonium tetrafluoroborate in propylene carbonate

Ultrasonic Relaxation Study of 1-Alkyl-3-methylimidazolium-Based Room-Temperature Ionic Liquids: Probing the Role of Alkyl Chain Length in the Cation.

Science.gov (United States)

Zorębski, Michał; Zorębski, Edward; Dzida, Marzena; Skowronek, Justyna; Jężak, Sylwia; Goodrich, Peter; Jacquemin, Johan

2016-04-14

Ultrasound absorption spectra of four 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imides were determined as a function of the alkyl chain length on the cation from 1-propyl to 1-hexyl from 293.15 to 323.15 K at ambient pressure. Herein, the ultrasound absorption measurements were carried out using a standard pulse technique within a frequency range from 10 to 300 MHz. Additionally, the speed of sound, density, and viscosity have been measured. The presence of strong dissipative processes during the ultrasound wave propagation was found experimentally, i.e., relaxation processes in the megahertz range were observed for all compounds over the whole temperature range. The relaxation spectra (both relaxation amplitude and relaxation frequency) were shown to be dependent on the alkyl side chain length of the 1-alkyl-3-methylimidazolium ring. In most cases, a single-Debye model described the absorption spectra very well. However, a comparison of the determined spectra with the spectra of a few other imidazolium-based ionic liquids reported in the literature (in part recalculated in this work) shows that the complexity of the spectra increases rapidly with the elongation of the alkyl chain length on the cation. This complexity indicates that both the volume viscosity and the shear viscosity are involved in relaxation processes even in relatively low frequency ranges. As a consequence, the sound velocity dispersion is present at relatively low megahertz frequencies.

Separation of toluene from cyclic hydrocarbons using 1-butyl-3-methylimidazolium methylsulfate ionic liquid at T = 298.15 K and atmospheric pressure

International Nuclear Information System (INIS)

Dominguez, Irene; Calvar, Noelia; Gomez, Elena; Dominguez, Angeles

2011-01-01

Highlights: → [BMim][MSO 4 ] was studied as solvent to extract toluene from cyclic hydrocarbons. → (Liquid + liquid) equilibrium data were measured at 298.15K and atmospheric pressure. → Selectivity and solute distribution ratio were obtained and compared with literature. → Experimental data were satisfactorily correlated using NRTL and UNIQUAC models. → [BMim][MSO 4 ] can be used as solvent for the studied (liquid + liquid) extraction. - Abstract: In this paper the extraction of toluene from cyclic hydrocarbons (cyclohexane, or methylcyclohexane, or cyclooctane, or cyclohexene) was analyzed by liquid extraction with 1-butyl-3-methylimidazolium methylsulfate ionic liquid, [BMim][MSO 4 ], as solvent. The experimental (liquid + liquid) equilibrium (LLE) data were determined at T = 298.15 K and atmospheric pressure. Solubility curves were obtained by the cloud point method and tie-line compositions were determined by density measurement. An analysis of the influence of different cyclic hydrocarbons on the extraction was performed. The effectiveness of the extraction of toluene from cyclic hydrocarbons was evaluated by means of the solute distribution ratio and selectivity values. The degree of consistency of the experimental LLE data was ascertained using the Othmer-Tobias and Hand equations. The experimental data for the (liquid + liquid) equilibria of the ternary systems were correlated with the Non-Random Two-Liquid (NRTL) and UNIversal QUAsi-Chemical (UNIQUAC) thermodynamic models.

Structure, conformations, vibrations, and ideal-gas properties of 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic pairs and constituent ions.

Science.gov (United States)

Paulechka, Yauheni U; Kabo, Gennady J; Emel'yanenko, Vladimir N

2008-12-11

Energies, geometries, and frequencies of normal vibrations have been calculated by quantum-chemical methods for different conformers of a bis(trifluoromethylsulfonyl)imide anion (NTf2-), 1-alkyl-3-methylimidazolium cations ([C(n)mim]+, n = 2, 4, 6, 8), and [C(n)mim]NTf2 ionic pairs. The assignment of frequencies for NTf2-, [C2mim]+, and [C4mim]+ in the vibrational spectra of ionic liquids have been performed. Thermodynamic properties of [C(n)mim]NTf2, [C(n)mim]+, and NTf2- in the gas state have been calculated by the statistical thermodynamic methods. The resulting entropies are in satisfactory agreement with the values obtained from the experimental data previously reported in literature.

Measurement and Correlation of the Ionic Conductivity of Ionic Liquid-Molecular Solvent Solutions

Institute of Scientific and Technical Information of China (English)

LI,Wen-Jing; HAN,Bu-Xing; TAO,Ran-Ting; ZHANG,Zhao-Fu; ZHANG,Jian-Ling

2007-01-01

The ionic conductivity of the solutions formed from 1-n-butyl-3-methylimidazolium tetrafluoroborate ([Bmim][BF4]) or 1-n-butyl-3-methylimidazolium hexafluorophosphate ([Bmim][PF6]) and different molecular solvents (MSs) were measured at 298.15 K. The molar conductivity of the ionic liquids (ILs) increased dramatically with increasing concentration of the MSs. It was found that the molar conductivity of the IL in the solutions studied in this work could be well correlated by the molar conductivity of the neat ILs and the dielectric constant and molar volume of the MSs.

Vapour Permeation and Sorption in Fluoropolymer Gel Membrane Based on Ionic Liquid 1-Ethyl-3-Methylimidazolium bis(trifluoromethylsulfonyl)Imide

Czech Academy of Sciences Publication Activity Database

Morávková, Lenka; Vopička, O.; Vejražka, Jiří; Vychodilová, Hana; Sedláková, Zuzana; Friess, K.; Izák, Pavel

2014-01-01

Roč. 68, č. 12 (2014), s. 1739-1746 ISSN 0366-6352 R&D Projects: GA ČR GAP106/10/1194; GA TA ČR TE01020080; GA MŠk(CZ) LD14094; GA MŠk(CZ) LD13018 Grant - others:GA ČR(CZ) GA13-32829P Institutional support: RVO:67985858 Keywords : ionic liquid membrane * hydrocarbon removal * volatile organic compound removal Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.468, year: 2014

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

Science.gov (United States)

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

2014-11-01

An ionic liquid foam floatation coupled with ionic liquid dispersive liquid-liquid microextraction method was proposed for the extraction and concentration of 17-α-estradiol, 17-β-estradiol-benzoate, and quinestrol in environmental water samples by high-performance liquid chromatography with fluorescence detection. 1-Hexyl-3-methylimidazolium tetrafluoroborate was applied as foaming agent in the foam flotation process and dispersive solvent in microextraction. The introduction of the ion-pairing and salting-out agent NH4 PF6 was beneficial to the improvement of recoveries for the hydrophobic ionic liquid phase and analytes. Parameters of the proposed method including concentration of 1-hexyl-3-methylimidazolium tetrafluoroborate, flow rate of carrier gas, floatation time, types and concentration of ionic liquids, salt concentration in samples, extraction time, and centrifugation time were evaluated. The recoveries were between 98 and 105% with relative standard deviations lower than 7% for lake water and well water samples. The isolation of the target compounds from the water was found to be efficient, and the enrichment factors ranged from 4445 to 4632. This developing method is free of volatile organic solvents compared with regular extraction. Based on the unique properties of ionic liquids, the application of foam floatation, and dispersive liquid-liquid microextraction was widened. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The scaled-charge additive force field for amino acid based ionic liquids

DEFF Research Database (Denmark)

Fileti, E. E.; Chaban, V. V.

2014-01-01

Ionic liquids (ILs) constitute an emerging research field. New ILs involve more and more organic and inorganic ions. Amino acid based ILs (AAILs) represent a specific interest due to their evolutional connection to proteins. We report a new non-polarizable force field (FF) for the eight AAILs...... comprising 1-ethyl-3-methylimidazolium cation and amino acid anions. The anions were obtained via deprotonation of carboxyl group. Specific cation-anion non-covalent interactions were taken into account by computing electrostatic potential for ion pairs. The van der Waals interactions were adopted from...

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

Science.gov (United States)

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

2014-05-19

In the search for uranium-based ionic liquids, tris(N,N-dialkyldithiocarbamato)uranylates have been synthesized as salts of the 1-butyl-3-methylimidazolium (C4mim) cation. As dithiocarbamate ligands binding to the UO2(2+) unit, tetra-, penta-, hexa-, and heptamethylenedithiocarbamates, N,N-diethyldithiocarbamate, N-methyl-N-propyldithiocarbamate, N-ethyl-N-propyldithiocarbamate, and N-methyl-N-butyldithiocarbamate have been explored. X-ray single-crystal diffraction allowed unambiguous structural characterization of all compounds except N-methyl-N-butyldithiocarbamate, which is obtained as a glassy material only. In addition, powder X-ray diffraction as well as vibrational and UV/Vis spectroscopy, supported by computational methods, were used to characterize the products. Differential scanning calorimetry was employed to investigate the phase-transition behavior depending on the N,N-dialkyldithiocarbamato ligand with the aim to establish structure-property relationships regarding the ionic liquid formation capability. Compounds with the least symmetric N,N-dialkyldithiocarbamato ligand and hence the least symmetric anions, tris(N-methyl-N-propyldithiocarbamato)uranylate, tris(N-ethyl-N-propyldithiocarbamato)uranylate, and tris(N-methyl-N-butyldithiocarbamato)uranylate, lead to the formation of (room-temperature) ionic liquids, which confirms that low-symmetry ions are indeed suitable to suppress crystallization. These materials combine low melting points, stable complex formation, and hydrophobicity and are therefore excellent candidates for nuclear fuel purification and recovery. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Activity coefficients at infinite dilution of organic solutes in 1-hexyl-3-methylimidazolium trifluoroacetate and influence of interfacial adsorption using gas–liquid chromatography

International Nuclear Information System (INIS)

Jiang, Lin-Kun; Wang, Li-Sheng; Du, Chao-Jun; Wang, Xue-Yuan

2014-01-01

Highlights: • Activity coefficients at infinite dilution of organic solutes in [HMIM][TFA] were determined. • The contribution of interfacial adsorption to the retention mechanism was estimated. • The partial molar excess enthalpies and the solubility parameters of [HMIM][TFA] were calculated. -- Abstract: Activity coefficients at infinite dilution for a series of organic solutes in the ionic liquid 1-hexyl-3-methylimidazolium trifluoroacetate ([HMIM][TFA]) have been determined by gas–liquid chromatography at the temperature range from (303.15 to 363.15) K. The contribution of interfacial adsorption to the retention mechanism was estimated by changing the loading of ionic liquid in stationary phase. The partial molar excess enthalpies at infinite dilution and the solubility parameters of ionic liquid were also calculated from the experimental values of activity coefficients at infinite dilution

Prediction of the thermodynamic properties of 1-alkyl-3-methylimidazolium lactate ionic liquids [C_nmim][Lact](n=2,3,4,5,and 6) by parachor

Institute of Scientific and Technical Information of China (English)

无

2010-01-01

An ionic liquid (IL) based on lactate,1-butyl-3-methylimidazolium lactate ([C4mim][Lact]),has been prepared and characterized by 1H nuclear magnetic resonance (NMR) spectroscopy and differential scanning calorimetry (DSC).Since the IL can form strong hydrogen bonds with water,trace water is a problematic impurity in the IL.Using the standard addition method (SAM),the density,refractive index and surface tension of [C4mim][Lact] were measured in the temperature range (308.15 to 343.15 ± 0.05) K.On the basis of the experimental data,the parachor and molar volume for [C4mim][Lact],and the molecular volume V m,surface tension γ,molar enthalpy of vaporization △lgHm 0,refractive index n D,and the thermal expansion coefficients,for the homologues [Cnmim][Lact] (n=2,3,4,5,and 6) were estimated using semi-empirical methods.The estimated values are in good agreement with the experimental data.

Thermodynamics of hydrogen bonding and van der Waals interactions of organic solutes in solutions of imidazolium based ionic liquids: “Structure-property” relationships

International Nuclear Information System (INIS)

Varfolomeev, Mikhail A.; Khachatrian, Artashes A.; Akhmadeev, Bulat S.; Solomonov, Boris N.

2016-01-01

Highlights: • Solution enthalpies of organic solutes in imidazolium based ionic liquids were measured. • van der Waals interactions scale of imidazolium based ionic liquids was proposed. • Enthalpies of solvation of organic solutes in ionic liquids were determined. • Hydrogen bond enthalpies of organic solutes with ionic liquids were calculated. • Relationships between structure of ionic liquids and thermochemical data were obtained. - Abstract: In the present work thermochemistry of intermolecular interactions of organic compounds in solutions of imidazolium based ionic liquids (ILs) has been studied using solution calorimetry method. Enthalpies of solution at infinite dilution of non-polar (alkanes, aromatic hydrocarbons) and polar (alcohols, amides, and etc.) organic solutes in two ionic liquids 1-butyl-3-methylimidazolium tetrafluoroborate and 1-butyl-3-methylimidazolium trifluoromethanesulfonate were measured at 298.15 K. The scale of van der Waals interactions of imidazolium based ILs has been proposed on the basis of solution enthalpies of n-alkanes in their media. The effect of the cation and anion structure of ILs on the enthalpies of solvation was analyzed. Enthalpies of hydrogen bonding of organic solutes with imidazolium based ILs were determined. It has been shown that these values are close to zero for proton acceptor solutes. At the same time, enthalpies of hydrogen bonding of proton donor solutes with ionic liquids are increased depending the anion: tetrafluoroborate ≈ bis(trifluoromethylsulfonyl)imide < 2-(2-methoxyethoxy)ethyl sulfate < trifluoromethanesulfonate. Enthalpies of van der Waals interactions and hydrogen bonding in the solutions of imidazolium based ionic liquids were compared with the same data for molecular solvents.

Thermodynamics of hydrogen bonding and van der Waals interactions of organic solutes in solutions of imidazolium based ionic liquids: “Structure-property” relationships

Energy Technology Data Exchange (ETDEWEB)

Varfolomeev, Mikhail A., E-mail: vma.ksu@gmail.com; Khachatrian, Artashes A.; Akhmadeev, Bulat S.; Solomonov, Boris N.

2016-06-10

Highlights: • Solution enthalpies of organic solutes in imidazolium based ionic liquids were measured. • van der Waals interactions scale of imidazolium based ionic liquids was proposed. • Enthalpies of solvation of organic solutes in ionic liquids were determined. • Hydrogen bond enthalpies of organic solutes with ionic liquids were calculated. • Relationships between structure of ionic liquids and thermochemical data were obtained. - Abstract: In the present work thermochemistry of intermolecular interactions of organic compounds in solutions of imidazolium based ionic liquids (ILs) has been studied using solution calorimetry method. Enthalpies of solution at infinite dilution of non-polar (alkanes, aromatic hydrocarbons) and polar (alcohols, amides, and etc.) organic solutes in two ionic liquids 1-butyl-3-methylimidazolium tetrafluoroborate and 1-butyl-3-methylimidazolium trifluoromethanesulfonate were measured at 298.15 K. The scale of van der Waals interactions of imidazolium based ILs has been proposed on the basis of solution enthalpies of n-alkanes in their media. The effect of the cation and anion structure of ILs on the enthalpies of solvation was analyzed. Enthalpies of hydrogen bonding of organic solutes with imidazolium based ILs were determined. It has been shown that these values are close to zero for proton acceptor solutes. At the same time, enthalpies of hydrogen bonding of proton donor solutes with ionic liquids are increased depending the anion: tetrafluoroborate ≈ bis(trifluoromethylsulfonyl)imide < 2-(2-methoxyethoxy)ethyl sulfate < trifluoromethanesulfonate. Enthalpies of van der Waals interactions and hydrogen bonding in the solutions of imidazolium based ionic liquids were compared with the same data for molecular solvents.

Blending municipal solid waste with corn stover for sugar production using ionic liquid process

Energy Technology Data Exchange (ETDEWEB)

Sun, Ning [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Xu, Feng [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Sandia National Laboratories (SNL-CA), Livermore, CA (United States); Sathitsuksanoh, Noppadon [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Thompson, Vicki S. [Idaho National Laboratory (INL), Idaho Falls, ID (United States); Cafferty, Kara [Idaho National Laboratory (INL), Idaho Falls, ID (United States); Li, Chenlin [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Tanjore, Deepti [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Narani, Akash [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Pray, Todd R. [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Simmons, Blake A. [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Sandia National Laboratories (SNL-CA), Livermore, CA (United States); Singh, Seema [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Sandia National Laboratories (SNL-CA), Livermore, CA (United States)

2015-06-01

Municipal solid waste (MSW) represents an attractive cellulosic resource for sustainable fuel production because of its abundance and its low or perhaps negative cost. However, the significant heterogeneity and toxic contaminants are barriers to efficient conversion to ethanol and other products. In this study, we generated MSW paper mix, blended with corn stover (CS), and have shown that both MSW paper mix alone and MSW/CS blends can be efficiently pretreated in certain ionic liquids (ILs) with high yields of fermentable sugars. After pretreatment in 1-ethyl-3-methylimidazolium acetate ([C₂C₁Im][OAc]), over 80% glucose has been released with enzymatic saccharification. We have also applied an enzyme free process by adding mineral acid and water directly into the IL/biomass slurry to induce hydrolysis. With the acidolysis process in the IL 1-ethyl-3-methylimidazolium chloride ([C₂C₁Im]Cl), up to 80% glucose and 90% xylose are released for MSW. The results indicate the feasibility of incorporating MSW as a robust blending agent for biorefineries.

CO2 Capture and Separation Properties in the Ionic Liquid 1-n-Butyl-3-Methylimidazolium Nonafluorobutylsulfonate

Directory of Open Access Journals (Sweden)

Lingyun Zhou

2014-05-01

Full Text Available Recently, the use of ionic liquids (ILs for carbon capture and separation processes has gained great interest by many researchers due to the high solubility of CO2 in ILs. In the present work, solubility measurements of CO2 in the novel IL 1-n-butyl-3-methylimidazolium nonafluorobutylsulfonate [C4mim][CF3CF2CF2CF2SO3] were performed with a high-pressure view-cell technique in the temperature range from 293.15 to 343.15 K and pressures up to about 4.2 MPa. For comparison, solubilities of H2, N2, and O2 in the IL were also measured at 323.15 K via the same procedure. The Krichevsky-Kasarnovsky equation was employed to correlate the measured solubility data. Henry’s law constants, enthalpies, and entropies of absorption for CO2 in the IL were also determined and presented. The CO2 solubility in this IL was compared with other ILs sharing the same cation. It was shown that the solubility of CO2 in these ILs follows the sequence: [C4mim][CF3CF2CF2CF2SO3] ≈ [C4mim][Tf2N] > [C4mim][CF3CF2CF2COO] > [C4mim][BF4], and the solubility selectivity of CO2 relative to O2, N2, and H2 in [C4mim][CF3CF2CF2CF2SO3] was 8, 16, and 22, respectively. Furthermore, this IL is regenerable and exhibits good stability. Therefore, the IL reported here would be a promising sorbent for CO2.

Hybrid electrolytes based on ionic liquids and amorphous porous silicon nanoparticles: Organization and electrochemical properties

KAUST Repository

Tchalala, Mohammed; El Demellawi, Jehad K.; Abou-Hamad, Edy; Duran Retamal, Jose Ramon; Varadhan, Purushothaman; He, Jr-Hau; Chaieb, Saharoui

2017-01-01

Ionic liquids (ILs) and ionic liquid-nanoparticle (IL-NP) hybrid electrolytes have garnered a lot of interest due to their unique properties that stimulate their use in various applications. Herein, we investigate the electrochemical and photo-physical properties of organic-inorganic hybrid electrolytes based on three imidazolium-based ionic liquids, i.e., 1-buthyl-3-methylimidazolium thiocyanate ([bmim] [SCN]), 1-ethyl-3-methylimidazolium tetrafluoroborate ([emim] [BF4]) and 1-buthyl-3-methylimidazolium acetate ([bmim] [Ac]) that are covalently tethered to amorphous porous silicon nanoparticles (ap-Si NPs). We found that the addition of ap-Si NPs confer to the ILs a pronounced boost in the electrocatalytic activity, and in mixtures of ap-Si NPs and [bmim] [SCN], the room-temperature current transport is enhanced by more than 5 times compared to bare [bmim] [SCN]. A detailed structural investigation by transmission electron microscope (TEM) showed that the ap-Si NPs were well dispersed, stabilized and highly aggregated in [bmim] [SCN], [emim] [BF4] and [bmim] [Ac] ILs, respectively. These observations correlate well with the enhanced current transport observed in ap-Si NPs/[bmim] [SCN] evidenced by electrochemical measurements. We interpreted these observations by the use of UV–vis absorbance, photoluminescence (PL), FTIR and solid-state NMR spectroscopy. We found that the ap-Si NPs/[bmim] [SCN] hybrid stands out due to its stability and optical transparency. This behavior is attributed to the iron(III) thiocyanate complexion as per the experimental findings. Furthermore, we found that the addition of NPs to [emim] [BF4] alters the equilibrium of the IL, which consequently improved the stability of the NPs through intermolecular interactions with the two ionic layers (anionic and cationic layers) of the IL. While in the case of [bmim] [Ac], the dispersion of ap-Si NPs was restrained because of the high viscosity of this IL.

Hybrid electrolytes based on ionic liquids and amorphous porous silicon nanoparticles: Organization and electrochemical properties

KAUST Repository

Tchalala, Mohammed

2017-05-06

Ionic liquids (ILs) and ionic liquid-nanoparticle (IL-NP) hybrid electrolytes have garnered a lot of interest due to their unique properties that stimulate their use in various applications. Herein, we investigate the electrochemical and photo-physical properties of organic-inorganic hybrid electrolytes based on three imidazolium-based ionic liquids, i.e., 1-buthyl-3-methylimidazolium thiocyanate ([bmim] [SCN]), 1-ethyl-3-methylimidazolium tetrafluoroborate ([emim] [BF4]) and 1-buthyl-3-methylimidazolium acetate ([bmim] [Ac]) that are covalently tethered to amorphous porous silicon nanoparticles (ap-Si NPs). We found that the addition of ap-Si NPs confer to the ILs a pronounced boost in the electrocatalytic activity, and in mixtures of ap-Si NPs and [bmim] [SCN], the room-temperature current transport is enhanced by more than 5 times compared to bare [bmim] [SCN]. A detailed structural investigation by transmission electron microscope (TEM) showed that the ap-Si NPs were well dispersed, stabilized and highly aggregated in [bmim] [SCN], [emim] [BF4] and [bmim] [Ac] ILs, respectively. These observations correlate well with the enhanced current transport observed in ap-Si NPs/[bmim] [SCN] evidenced by electrochemical measurements. We interpreted these observations by the use of UV–vis absorbance, photoluminescence (PL), FTIR and solid-state NMR spectroscopy. We found that the ap-Si NPs/[bmim] [SCN] hybrid stands out due to its stability and optical transparency. This behavior is attributed to the iron(III) thiocyanate complexion as per the experimental findings. Furthermore, we found that the addition of NPs to [emim] [BF4] alters the equilibrium of the IL, which consequently improved the stability of the NPs through intermolecular interactions with the two ionic layers (anionic and cationic layers) of the IL. While in the case of [bmim] [Ac], the dispersion of ap-Si NPs was restrained because of the high viscosity of this IL.

Cellulose gels produced in room temperature ionic liquids by ionizing radiation

International Nuclear Information System (INIS)

Kimura, Atsushi; Nagasawa, Naotsugu; Taguchi, Mitsumasa

2014-01-01

Cellulose-based gels were produced in room temperature ionic liquids (RTILs) by ionizing radiation. Cellulose was dissolved at the initial concentration of 20 wt% in 1-ethyl-3-methylimidazolium (EMI)-acetate or N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium (DEMA)-formate with a water content of 18 wt%, and irradiated with γ-rays under aerated condition to produce new cellulose gels. The gel fractions of the cellulose gels obtained in EMI-acetate and DEMA-formate at a dose of 10 kGy were 13% and 19%, respectively. The formation of gel fractions was found to depend on the initial concentration of cellulose, water content, and irradiation temperature. The obtained gel readily absorbed water, methanol, ethanol, dichloromethane, N,N-dimethylacetamide, and RTILs. - Highlights: • Cellulose gels were produced in room temperature ionic liquids (RTILs). • Water plays a crucial role in the cross-linking reaction. • Cellulose gels swollen with RTILs show good electronic conductivity (3.0 mS cm −1 )

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

Directory of Open Access Journals (Sweden)

Michael L. Hainstock

2015-01-01

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

Study of thioglycosylation in ionic liquids

Directory of Open Access Journals (Sweden)

Ragauskas Arthur

2006-06-01

Full Text Available Abstract A novel, green chemistry, glycosylation strategy was developed based upon the use of ionic liquids. Research studies demonstrated that thiomethyl glycosides could readily be activated with methyl trifluoromethane sulfonate, using 1-butyl-3-methylimidazolium tetrafluoroborate as a solvent. This green chemistry glycosylation strategy provided disaccharides with typical yields averaging 75%. The ionic liquid solvent could be readily reused for five sequential glycosylation reactions with no impact on product yield.

Ionic liquids influence on the surface properties of electron beam irradiated wood

Energy Technology Data Exchange (ETDEWEB)

Croitoru, Catalin [“Transilvania” University of Brasov, Product Design and Environment Department, 29 Eroilor Str., 500036, Brasov (Romania); Patachia, Silvia, E-mail: st.patachia@unitbv.ro [“Transilvania” University of Brasov, Product Design and Environment Department, 29 Eroilor Str., 500036, Brasov (Romania); Doroftei, Florica; Parparita, Elena; Vasile, Cornelia [“Petru Poni” Institute of Macromolecular Chemistry, Physical Chemistry of Polymers Department, 41A Gr. Ghica Voda Alley, Iasi (Romania)

2014-09-30

Highlights: • Wood veneers impregnated with three imidazolium-based ionic liquids and irradiated with electron beam were studied by FTIR-ATR, SEM/EDX, AFM, contact angle and image analysis. • ILs preserve the surface properties of the wood (surface energy, roughness, color) upon irradiation, in comparison with the reference wood, but the surface composition is changed by treatment with IL-s, mainly with 1-butyl-3-methylimidazolium tetrafluoroborate. • Under electron beam irradiation covalent bonding of the imidazolium moiety to wood determines a higher resistance to water penetration and spreading on the surface. - Abstract: In this paper, the influence of three imidazolium-based ionic liquids (1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate and 1-hexyl-3-methylimidazolium chloride) on the structure and surface properties of sycamore maple (Acer pseudoplatanus) veneers submitted to electron beam irradiation with a dose of 50 kGy has been studied by using Fourier transform infrared spectroscopy, as well as image, scanning electron microscopy/SEM/EDX, atomic force microscopy and contact angle analysis. The experimental results have proven that the studied ionic liquids determine a better preservation of the structural features of wood (cellulose crystallinity index and lignin concentration on the surface) as well as some of surface properties such as surface energy, roughness, color upon irradiation with electron beam, in comparison with the reference wood, but surface composition is changed by treatment with imidazolium-based ionic liquids mainly with 1-butyl-3-methylimidazolium tetrafluoroborate. Also, under electron beam irradiation covalent bonding of the imidazolium moiety to wood determines a higher resistance to water penetration and spreading on the surface.

Estimation of physicochemical properties of 1-alkyl-3-methylimidazolium glutamate

International Nuclear Information System (INIS)

Fang, Da-wei; Yan, Qiang; Li, Du; Xia, Li-Xin; Zang, Shu-Liang

2014-01-01

Highlights: • The standard addition method (SAM) was applied in determination of density and surface tension of amino acid ionic liquids. • The molar refraction has been calculated by experimental data of refractive index. • Physico-chemical properties of the homologue of [C n mim][Glu] have been predicted by semiempirical methods. - Abstract: Amino acid ionic liquids (AAILs) [C 5 mim][Glu] (1-pentyl-3-methylimidazolium glutamate) and [C 6 mim][Glu] (1-hexyl-3-methylimidazolium glutamate) were prepared by the neutralization method and characterized by 1 H NMR spectroscopy and DSC. The values of their density, surface tension were measured over the temperature range (308.15 to 343.15 ± 0.05) K, and the refractive index was measured within the temperature range (293.15 to 328.15 ± 0.05) K. Since the AAILs can form strong hydrogen bonds with water, a small amount of water is difficult to remove from the AAILs by common methods. In order to eliminate the effect of water as an impurity existed in AAIL sample, the standard addition method (SAM) was applied to these measurements. In terms of a semi-empirical method, the following physico-chemical properties were predicted: molecular volume, V m , standard molar entropy, S 0 , parachor, P, surface tension, γ, thermal expansion coefficients, α, molar refraction, R M , and refractive index, n D , of the homologue of [C n mim][Glu] (n = 2, 3, 4)

Determination and modelling of osmotic coefficients and vapour pressures of binary systems 1- and 2-propanol with CnMimNTf2 ionic liquids (n = 2, 3, and 4) at T = 323.15 K

International Nuclear Information System (INIS)

Calvar, Noelia; Gomez, Elena; Dominguez, Angeles; Macedo, Eugenia A.

2011-01-01

Highlights: → Osmotic coefficients of 1- and 2-propanol with C n MimNTf 2 (n = 2, 3, and 4) are determined. → Experimental data were correlated with extended Pitzer model of Archer and MNRTL. → Mean molal activity coefficients and excess Gibbs free energies were calculated. → Effect of the anion is studied comparing these results with literature. - Abstract: The osmotic and activity coefficients and vapour pressures of binary mixtures containing 1-propanol, or 2-propanol and imidazolium-based ionic liquids with bis(trifluoromethylsulfonyl)imide as anion (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, C 2 MimNTf 2 , 1-methyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide, C 3 MimNTf 2 , and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, C 4 MimNTf 2 ) were determined at T = 323.15 K using the vapour pressure osmometry technique. The experimental osmotic coefficients were correlated using the extended Pitzer model modified by Archer and the MNRTL model, obtaining standard deviations lower than 0.033 and 0.064, respectively. The mean molal activity coefficients and the excess Gibbs free energy for the mixtures studied were calculated from the parameters of the extended Pitzer model modified by Archer. Besides the effect of the alkyl-chain of the cation, the effect of the anion can be assessed comparing the experimental results with those previously obtained for imidazolium ionic liquids with sulphate anions.

Liquid densities and excess molar volumes for (ionic liquids + methanol + water) ternary system at atmospheric pressure and at various temperatures

Energy Technology Data Exchange (ETDEWEB)

Deenadayalu, Nirmala [Department of Chemistry, Durban University of Technology, Steve Biko Campus, P.O. Box 1334, Durban, KwaZulu-Natal 4001 (South Africa)], E-mail: NirmalaD@dut.ac.za; Kumar, Satish; Bhujrajh, Pravena [Department of Chemistry, Durban University of Technology, Steve Biko Campus, P.O. Box 1334, Durban, KwaZulu-Natal 4001 (South Africa)

2007-09-15

Excess molar volumes, V{sub m}{sup E} have been evaluated from density measurements over the entire composition range for ternary liquid system of ionic liquid (1-ethyl-3-methyl-imidazolium diethylenglycol monomethylether sulphate {l_brace}[EMIM][CH{sub 3}(OCH{sub 2}CH{sub 2}){sub 2}OSO{sub 3}]) (1) + methanol (2) + water (3){r_brace} at T = (298.15, 303.15, and 313.15) K. A vibrating tube densimeter was used for these measurements at atmospheric pressure. The V{sub m}{sup E} values were found to be negative at T = (298.15 and 303.15) K. For {l_brace}[EMIM][CH{sub 3}(OCH{sub 2}CH{sub 2}){sub 2}OSO{sub 3}] (1) + methanol (2) + water (3){r_brace} at T = 313.15 K the V{sub m}{sup E} values become positive at higher mole fraction of ionic liquid and at a corresponding decrease in mole fraction of water. All the experimental data were fitted with the Redlich-Kister equation. The results have also been analysed in term of graph theoretical approach.

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

Science.gov (United States)

Zhao, Kai; Li, Dongqing

2018-07-13

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

Helium Nanodroplet Isolation and Infrared Spectroscopy of the Isolated Ion-Pair 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide

Science.gov (United States)

2013-09-01

Isolated Ion- Pair 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide   Emmanuel I. Obi†, Christopher M. Leavitt†, Paul L. Raston... Christopher P. Moradi†, Steven D.   Flynn†, Jerry A. Boatz§,*, Steven D. Chambreau‡,* and Gary E. Douberly†,*     †Department of Chemistry, University of...Windus, T. L.; Dupuis , M.; Montgomery, J. A. General Atomic and Molecular Electronic-Structure System. J. Comput. Chem. 1993, 14, 1347-1363

Improved in situ saccharification of cellulose pretreated by dimethyl sulfoxide/ionic liquid using cellulase from a newly isolated Paenibacillus sp. LLZ1.

Science.gov (United States)

Hu, Dongxue; Ju, Xin; Li, Liangzhi; Hu, Cuiying; Yan, Lishi; Wu, Tianyun; Fu, Jiaolong; Qin, Ming

2016-02-01

A cellulase producing strain was newly isolated from soil samples and identified as Paenibacillus sp. LLZ1. A novel aqueous-dimethyl sulfoxide (DMSO)/1-ethyl-3-methylimidazolium diethyl phosphate ([Emin]DEP)-cellulase system was designed and optimized. In the pretreatment, DMSO was found to be a low-cost substitute of up to 70% ionic liquid to enhance the cellulose dissolution. In the enzymatic saccharification, the optimum pH and temperature of the Paenibacillus sp. LLZ1 cellulase were identified as 6.0 and 40°C, respectively. Under the optimized reaction condition, the conversion of microcrystalline cellulose and bagasse cellulose increased by 39.3% and 37.6%, compared with unpretreated cellulose. Compared to current methods of saccharification, this new approach has several advantages including lower operating temperature, milder pH, and less usage of ionic liquid, indicating a marked progress in environmental friendly hydrolysis of biomass-based materials. Copyright © 2015 Elsevier Ltd. All rights reserved.

Ionic Liquid as a Solvent and Catalyst for Acylation of Maltodextrin

Science.gov (United States)

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

A roadmap to uranium ionic liquids: Anti-crystal engineering

Energy Technology Data Exchange (ETDEWEB)

Yaprak, Damla; Spielberg, Eike T.; Baecker, Tobias; Richter, Mark; Mallick, Bert [Inorganic Chemistry III, Ruhr-University Bochum (Germany); Klein, Axel [Institut fuer Anorganische Chemie, Koeln Univ. (Germany); Mudring, Anja-Verena [Inorganic Chemistry III, Ruhr-University Bochum (Germany); Materials Science and Engineering, Iowa State University and Critical Materials Institute, Ames Laboratory, Ames, IA (United States)

2014-05-19

In the search for uranium-based ionic liquids, tris(N,N-dialkyldithiocarbamato)uranylates have been synthesized as salts of the 1-butyl-3-methylimidazolium (C{sub 4}mim) cation. As dithiocarbamate ligands binding to the UO{sub 2}{sup 2+} unit, tetra-, penta-, hexa-, and heptamethylenedithiocarbamates, N,N-diethyldithiocarbamate, N-methyl-N-propyldithiocarbamate, N-ethyl-N-propyldithiocarbamate, and N-methyl-N-butyldithiocarbamate have been explored. X-ray single-crystal diffraction allowed unambiguous structural characterization of all compounds except N-methyl-N-butyldithiocarbamate, which is obtained as a glassy material only. In addition, powder X-ray diffraction as well as vibrational and UV/Vis spectroscopy, supported by computational methods, were used to characterize the products. Differential scanning calorimetry was employed to investigate the phase-transition behavior depending on the N,N-dialkyldithiocarbamato ligand with the aim to establish structure-property relationships regarding the ionic liquid formation capability. Compounds with the least symmetric N,N-dialkyldithiocarbamato ligand and hence the least symmetric anions, tris(N-methyl-N-propyldithiocarbamato)uranylate, tris(N-ethyl-N-propyldithiocarbamato)uranylate, and tris(N-methyl-N-butyldithiocarbamato)uranylate, lead to the formation of (room-temperature) ionic liquids, which confirms that low-symmetry ions are indeed suitable to suppress crystallization. These materials combine low melting points, stable complex formation, and hydrophobicity and are therefore excellent candidates for nuclear fuel purification and recovery. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

A roadmap to uranium ionic liquids: Anti-crystal engineering

International Nuclear Information System (INIS)

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

2014-01-01

In the search for uranium-based ionic liquids, tris(N,N-dialkyldithiocarbamato)uranylates have been synthesized as salts of the 1-butyl-3-methylimidazolium (C_4mim) cation. As dithiocarbamate ligands binding to the UO_2"2"+ unit, tetra-, penta-, hexa-, and heptamethylenedithiocarbamates, N,N-diethyldithiocarbamate, N-methyl-N-propyldithiocarbamate, N-ethyl-N-propyldithiocarbamate, and N-methyl-N-butyldithiocarbamate have been explored. X-ray single-crystal diffraction allowed unambiguous structural characterization of all compounds except N-methyl-N-butyldithiocarbamate, which is obtained as a glassy material only. In addition, powder X-ray diffraction as well as vibrational and UV/Vis spectroscopy, supported by computational methods, were used to characterize the products. Differential scanning calorimetry was employed to investigate the phase-transition behavior depending on the N,N-dialkyldithiocarbamato ligand with the aim to establish structure-property relationships regarding the ionic liquid formation capability. Compounds with the least symmetric N,N-dialkyldithiocarbamato ligand and hence the least symmetric anions, tris(N-methyl-N-propyldithiocarbamato)uranylate, tris(N-ethyl-N-propyldithiocarbamato)uranylate, and tris(N-methyl-N-butyldithiocarbamato)uranylate, lead to the formation of (room-temperature) ionic liquids, which confirms that low-symmetry ions are indeed suitable to suppress crystallization. These materials combine low melting points, stable complex formation, and hydrophobicity and are therefore excellent candidates for nuclear fuel purification and recovery. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Why are ionic liquid ions mainly associated in water? A Car-Parrinello study of 1-ethyl-3-methyl-imidazolium chloride water mixture

Science.gov (United States)

Spickermann, C.; Thar, J.; Lehmann, S. B. C.; Zahn, S.; Hunger, J.; Buchner, R.; Hunt, P. A.; Welton, T.; Kirchner, B.

2008-09-01

In this study we present the results of a first principles molecular dynamics simulation of a single 1-ethyl-3-methyl-imidazolium chloride [C2C1im][Cl] ion pair dissolved in 60 water molecules. We observe a preference of the in plane chloride coordination with respect to the cation ring plane as compared to the energetic slightly more demanding on top coordination. Evaluation of the different radial distribution functions demonstrates that the structure of the hydration shell around the ion pair differs significantly from bulk water and that no true ion pair dissociation in terms of completely autonomous solvation shells takes place on the timescale of the simulation. In addition, dipole moment distributions of the solvent in distinct solvation shells around different functional parts of the [C2C1im][Cl] ion pair are calculated from maximally localized Wannier functions. The analysis of these distributions gives evidence for a depolarization of water molecules close to the hydrophobic parts of the cation as well as close to the anion. Examination of the angular distribution of different OH(H2O )-X angles in turn shows a linear coordination of chloride accompanied by a tangential orientation of water molecules around the hydrophobic groups, being a typical feature of hydrophobic hydration. Based on these orientational aspects, a structural model for the obvious preference of ion pair association is developed, which justifies the associating behavior of solvated [C2C1im][Cl] ions in terms of an energetically favorable interface between the solvation shells of the anion and the hydrophobic parts of the cation.

Separation of 1,3-substituted imidazoles for quality control of a Lewis acidic ionic liquid for aluminum electroplating.

Science.gov (United States)

Kosmus, Patrick; Steiner, Oliver; Goessler, Walter; Gollas, Bernhard

2014-05-01

Ionic liquids (ILs) are already used or have great potential in many industrial applications. Knowledge about their unique physicochemical characteristics makes ILs suitable for the electrodeposition of metals with very low negative potentials. Aluminum with its good corrosion protection behavior has great capability to be electroplated from IL electrolytes on steel substrates. The stability of the chosen electrolyte is very important to ensure industrial applicability. In this study, temperature and electrochemical long-term stability from electrolytes based on a Lewis acidic mixture of AlCl3 and 1-ethyl-3-methylimidazolium chloride are investigated. A published method was modified to identify possible degradation products using mass spectrometric detection. The optimized method used an Agilent Zorbax SB-Phenyl column (2.0 × 150 mm, 5 μm particles) with a 20 mmol TFA and 5% ACN mobile phase. This method allowed the quantification of several imidazoles from 0.1 to 100 mg/L. When analyzing the long-term stressed electrolytes, no significant changes in electrolyte composition could be observed. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electrochemical storage of polypyrrole-Fe{sub 2}O{sub 3} nanocomposites in ionic liquids

Energy Technology Data Exchange (ETDEWEB)

Mallouki, M. [Laboratoire de Physicochimie des Polymeres et des Interfaces, 5, mail Gay-Lussac, F-95031 Cergy-Pontoise Cedex (France); Tran-Van, F. [Laboratoire de Physico-Chimie des Materiaux et des Biomolecules/(EA 4244), Universite de Tours, Faculte des Sciences et Techniques, parc de Grandmont, 37200 Tours (France)], E-mail: francois.tran@univ-tours.fr; Sarrazin, C. [Laboratoire de Physicochimie des Polymeres et des Interfaces, 5, mail Gay-Lussac, F-95031 Cergy-Pontoise Cedex (France); Chevrot, C. [Laboratoire de Physicochimie des Polymeres et des Interfaces, 5, mail Gay-Lussac, F-95031 Cergy-Pontoise Cedex (France)], E-mail: claude.chevrot@u-cergy.fr; Fauvarque, J.F. [CNAM, Laboratoire d' Electrochimie Industrielle, 75003 Paris (France)

2009-04-15

Electroactive polypyrrole-Fe{sub 2}O{sub 3} nanocomposite materials were prepared by chemical polymerization of pyrrole in aqueous Fe{sub 2}O{sub 3} colloidal solution, using FeCl{sub 3} as oxidant and tosylate anions (TS) as doping agent. The nanocomposite material named (PPyTSNC) was studied by X-ray diffraction analysis, Fourier Transform Infra-Red spectroscopy and thermogravimetric analysis. Their electrochemical storage properties were investigated on composite electrodes using 80% in weight of active materials in different immidazolium and pyrrolidinium based room temperature ionic liquids (RTILs) as electrolytes. Cyclic voltammetry and constant current charge discharge cycling showed high charge storage properties of the nanocomposite based electrodes in 1-ethyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)imide (EMITFSI) and N-butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR{sub 14}TFSI) (respectively 72 mAh/g and 62 mAh/g at 1 mA/cm{sup 2} discharge current) which are more than twice higher than the values obtained with pure PPy. These improvements in capacities have been attributed to the PPyTSNC morphology modification which ensures a large incorporation of the electrolyte inside the nanostructure. The specific capacitances of the nanocomposite electrodes reached 210 F/g and 190 F/g in EMITFSI and PYR{sub 14}TFSI and their cyclability has shown only 3-5% capacitance loss after one thousand cycles for both ionic liquids.

Synthesis and characterization of ionic liquid (EMImBF{sub 4})/Li{sup +} - chitosan membranes for ion battery

Energy Technology Data Exchange (ETDEWEB)

Pasaribu, Marvin H., E-mail: marvin-shady88@yahoo.com; Arcana, I Made, E-mail: arcana@chem.itb.ac.id; Wahyuningrum, Deana, E-mail: deana@chem.itb.ac.id [Department of Chemistry, Faculty of Mathematics and Natural Sciences, InstitutTeknologi Bandung, Jl. Ganesha No. 10, Bandung 40132 (Indonesia)

2015-09-30

Lithium ion battery has been currently developed and produced because it has a longer life time, high energycapacity, and the efficient use of lithium ion battery that is suitable for storing electrical energy. However, this battery has some drawbacks such as use liquid electrolytes that are prone to leakage and flammability during the battery charging process in high temperature. In this study, an ionic liquid 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF4) containing Li{sup +} ions was synthesized and combined with chitosan polymer host as a polymer electrolyte membrane for lithium-ion batteries to solve this problems. This ionic liquid was obtained from the anion metathesis reaction between EMImBr and LiBF4 salt, while EMImBr was synthesized from the reaction between 1-methylimidazole and ethyl bromide utilizing Microwave Assisted Organic Synthesis (MAOS) method. The ionic liquid obtained was characterized by microstructure analysis with using NMR and FTIR spectroscopy. The polymer electrolyte membrane was characterized by analysis functional groups (FTIR), ionic conductivity (EIS), and surface morphology (SEM). The analysis results of ion conductivity by the EIS method showed the increase the ionic conductivity value of membranes from 1.30 × 10{sup −2} S cm{sup −1} for chitosan to 1.30 × 10{sup −2} S cm{sup −1} for chitosan with EMImBF4/Li{sup +}, and this result was supported by analysis the surface morphology (SEM)

Mass spectrometric studies of 1-ethyl-3-methylimidazolium and 1-propyl-2,3-dimethylimidazolium bis(trifluoromethyl)-sulfonylimides.

Science.gov (United States)

Chilingarov, Norbert S; Medvedev, Artem A; Deyko, Grigoriy S; Kustov, Leonid M; Chernikova, Elena A; Glukhov, Lev M; Markov, Vitaliy Yu; Ioffe, Il'ya N; Senyavin, Vladimir M; Polyakova, Marina V; Sidorov, Lev N

2015-07-15

Ionic liquids ([Cat(+)][An(-)]) were believed to decompose before reaching vaporization temperatures, but recently some of them have been shown to vaporize congruently. Low-temperature vaporization of ionic substances is an intriguing phenomenon, so the vapor-phase composition and reactions of ionic liquids deserve more extensive study. Evaporation of two ionic liquids, [C2MIM(+)][Tf2 N(-)] and [C3MMIM(+)][Tf2N(-)], was studied by means of Knudsen effusion mass spectrometry. These liquids were also characterized using matrix-assisted laser desorption/ionization (MALDI) mass spectrometry, UV/Vis, IR, NMR spectroscopy, and elemental analysis. The vaporization enthalpies of (118 ± 3) and (124 ± 2) kJ·mol(-1) were determined for [C2MIM(+)][Tf2N(-)] and [C3MMIM(+)][Tf2N(-)], respectively. The corresponding equations for their saturated vapor pressures are: ln(p{[C2MIM(+)][Tf2N(-)]}/Pa) = -(14213 ± 325)/(T/K) + (26.57 ± 1.04), ln(p{[C2MMIM(+)][Tf2N(-)]}/Pa) = -(14868 ± 221)/(T/K) + (27.19 ± 0.60). The MALDI studies (positive and negative ion modes) enabled detection of monomeric [Cat(+)] and [An(-)] ions, the cluster ions {[Cat(+)]2 [An(-)]}(+) and {[Cat(+)][An(-)]2}(-), and some complex anions {2[An(-)] + Na(+)}(-), {2[An(-)] + K(+)}(-), {2[An(-)] + Cu(+)}(-) and {3[An(-)] + Ca(2+)}(-). Knudsen effusion mass spectrometry proved to be a valuable method to study the thermodynamics of ionic liquids. The saturated vapor pressure and vaporization enthalpy of [C3MMIM(+)][Tf2N(-)] were accurately determined for the first time. MALDI is also capable of providing indirect information on hydrogen bonding. Copyright © 2015 John Wiley & Sons, Ltd.

Measurement and correlation of vapour pressures of pyridine and thiophene with [EMIM][SCN] ionic liquid

International Nuclear Information System (INIS)

Khelassi-Sefaoui, Asma; Mutelet, Fabrice; Mokbel, Ilham; Jose, Jacques; Negadi, Latifa

2014-01-01

Highlights: • VLE of (pyridine + [EMIM][SCN]), or (thiophene + [EMIM][SCN]) binary mixtures were measured. • The investigated temperatures are 273 K to 363 K. • The PC-SAFT equation of state has been used to correlate the vapour pressures of the binary systems. - Abstract: In this work (vapour + liquid) equilibrium (VLE) measurements were performed on binary systems of the ionic liquid 1-ethyl-3-methylimidazolium thiocynate [EMIM][SCN] with thiophene or pyridine at pressures close to the atmospheric pressure using a static device at temperatures between 273 K and 363 K. Experimental data were correlated by the PC-SAFT EoS. The binary interaction parameters k ij were optimised on experimental VLE data. The results obtained for the two binary mixtures studied in this paper indicate that the PC-SAFT EoS can be used to represent systems containing ionic liquids

Separation of benzene from alkanes using 1-ethyl-3-methylpyridinium ethylsulfate ionic liquid at several temperatures and atmospheric pressure: Effect of the size of the aliphatic hydrocarbons

International Nuclear Information System (INIS)

Gonzalez, Emilio J.; Calvar, Noelia; Gomez, Elena; Dominguez, Angeles

2010-01-01

The ionic liquid 1-ethyl-3-methylpyridinium ethylsulfate, [EMpy][ESO 4 ], was studied for the separation of benzene from aliphatic hydrocarbons (octane or nonane) by solvent extraction through the determination of the (liquid + liquid) equilibrium (LLE) of the ternary systems: {octane (1) + benzene (2) + [EMpy][ESO 4 ] (3)} and {nonane (1) + benzene (2) + [EMpy][ESO 4 ] (3)} at T = (283.15 and 298.15) K and atmospheric pressure. Binodal curves were determined using the 'cloud point' method, and tie-line compositions were obtained by density measurements. The values of selectivity and distribution coefficient, derived from the tie-line data, were used to decide if this ionic liquid can be used as potential solvent for the separation of benzene from aliphatic hydrocarbons using liquid extraction. These results were analyzed and compared to those previously reported for the systems {hexane + benzene + [EMpy][ESO 4 ]} and {heptane + benzene + [EMpy][ESO 4 ]}. The experimental results show that this ionic liquid is suitable for the extraction of benzene from mixtures containing octane and nonane. The consistency of tie-line data was ascertained by applying the Othmer-Tobias and Hand equations. The experimental results for the ternary systems were well correlated with the NRTL model. No literature data were found for the mixtures discussed in this paper.

The effect of the alkyl chain length on physicochemical features of (ionic liquids + γ-butyrolactone) binary mixtures

International Nuclear Information System (INIS)

Papović, Snežana; Bešter-Rogač, Marija; Vraneš, Milan; Gadžurić, Slobodan

2016-01-01

Highlights: • Influence of alkyl substituent length on IL properties was studied. • Nature of interactions between studied [C_nC_1im][NTf_2] and GBL were discussed. • Angell strength parameter indicates [C_nC_1im][NTf_2] are fragile liquids. • ILs properties regularly change with increase of the alkyl chain length. • Absence of GBL self-association upon addition of IL is observed. - Abstract: Densities and viscosities were determined and analysed for γ-butyrolactone (GBL) binary mixtures with 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquids (where alkyl = ethyl, hexyl, octyl) as a function of temperature at atmospheric pressure (p = 0.1 MPa) and over the whole composition range. Excess molar volumes have been calculated from the experimental densities and were fitted using Redlich–Kister’s polynomial equation. Other volumetric parameters have been also calculated in order to obtain information about interactions between GBL and imidazolium based ionic liquids with different alkyl chain length. From the viscosity measurements, the Angell strength parameter was calculated for pure ionic liquids indicating that all investigated electrolytes are “fragile” liquids.

Effect of degree of crosslinking and polymerization of 3D printable polymer/ionic liquid composites on performance of stretchable piezoresistive sensors

Science.gov (United States)

Lee, Jeongwoo; Faruk Emon, Md Omar; Vatani, Morteza; Choi, Jae-Won

2017-03-01

Ionic liquid (IL)/polymer composites (1-ethyl-3-methyl-imidazolium tetrafluoroborate (EMIMBF4)/2-[[(butylamino)carbonyl]oxy]ethyl acrylate (BACOEA)) were fabricated to use as sensing materials for stretchable piezoresistive tactile sensors. The detectability of the IL/polymer composites was enhanced because the ionic transport properties of EMIMBF4 in the composites were improved by the synergic actions between the coordinate sites generated by the local motion of BACOEA chain segments under enough activation energy. The performance of the piezoresistive sensors was investigated with the degree of crosslinking and polymerization of the IL/polymer composites. As the compressive strain was increased, the distance between two electrodes decreased, and the motion of polymer chains and IL occurred, resulting in a decrease in the electrical resistance of the sensors. We have confirmed that the sensitivity of the sensors are affected by the degree of crosslink and polymerization of the IL/polymer composites. In addition, all of the materials (skins, sensing material, and electrode) used in this study are photo-curable, and thus the stretchable piezoresistive tactile sensors can be successfully fabricated by 3D printing.

Measurements of activity coefficients at infinite dilution of aromatic and aliphatic hydrocarbons, alcohols, and water in the new ionic liquid [EMIM][SCN] using GLC

International Nuclear Information System (INIS)

Domanska, Urszula; Marciniak, Andrzej

2008-01-01

A new ionic liquid was chosen for the separation of aromatic hydrocarbons from aliphatic hydrocarbons. The activity coefficients at infinite dilution, γ 13 ∞ for 29 solutes: alkanes, alkenes, alkynes, cycloalkanes, aromatic hydrocarbons, alcohols, and water in the ionic liquid 1-ethyl-3-methyl-imidazolium thiocyanate [EMIM][SCN] were determined by gas-liquid chromatography at the temperatures from 298.15 K to 368.15 K. The values of the partial molar excess enthalpies at infinite dilution ΔH 1 E,∞ were calculated from the experimental γ 13 ∞ values obtained over the temperature range. The selectivities for the hexane/benzene and cyclohexane/benzene separation problems were calculated from the γ 13 ∞ and compared to the other ionic liquids, NMP and sulfolane, taken from the recent literature. This work demonstrates that with chosen ionic liquid it is possible to separate different organic compounds with the highest selectivity ever published

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

International Nuclear Information System (INIS)

Mehrdad, Abbas; Shekaari, Hemayat; Niknam, Zahra

2014-01-01

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

Odd-even effect on the formation of aqueous biphasic systems formed by 1-alkyl-3-methylimidazolium chloride ionic liquids and salts

Science.gov (United States)

Belchior, Diana C. V.; Sintra, Tânia E.; Carvalho, Pedro J.; Soromenho, Mário R. C.; Esperança, José M. S. S.; Ventura, Sónia P. M.; Rogers, Robin D.; Coutinho, João A. P.; Freire, Mara G.

2018-05-01

This work provides a comprehensive evaluation of the effect of the cation alkyl side chain length of the 1-alkyl-3-methylimidazolium chloride series ([CnC1im]Cl, n = 2-14) of ionic liquids (ILs) on their capability to form aqueous biphasic systems (ABSs) with salts and self-aggregation derived properties. The liquid-liquid phase behavior of ternary systems composed of [CnC1im]Cl, water, and K3PO4 or K2CO3 and the respective Setschenow salting-out coefficients (ks), a quantitative measure of the two-phase formation ability, were determined. An odd-even effect in the ks values along the number of methylene groups of the longest IL cation alkyl side chain was identified for the ABS formed by K2CO3, a weaker salting-out agent where the phenomenon is clearly identified. In general, cations with even alkyl side chains, being likely to display higher molar volumes, are more easily salted-out and thus more prone to undergo phase separation. The odd-even effect in the ks values is, however, more significant in ILs up to n = 6, where the nanostructuration/nanosegregation of ILs plays a less relevant role. Still, with the [CnC1im]Cl (n = 7-14) series of ILs, an odd-even effect was also identified in the ILs' ionization degree, molar conductivity, and conductivity at infinite dilution. In summary, it is shown here that the ILs' odd-even effect occurs in IL aqueous solutions and not just in neat ILs, an already well-established phenomenon occurring in a series of ILs' properties described as a result of the orientation of the terminal methyl groups to the imidazolium ring cation and consequent effect in the ILs' cohesive energy.

Quaternary (liquid + liquid) equilibrium data for the extraction of toluene from alkanes using the ionic liquid [EMim][MSO4

International Nuclear Information System (INIS)

Corderí, Sandra; Calvar, Noelia; Gómez, Elena; Domínguez, Ángeles

2014-01-01

Highlights: • EMim[MSO 4 ] was proposed as solvent for the extraction of toluene from alkanes. • The quaternary system {heptane + cyclohexane + toluene + [EMim][MSO 4 ]} was evaluated. • The extraction of toluene would be facilitated in the presence of one alkane. • Experimental LLE data were successfully correlated with the NRTL model. - Abstract: (Liquid + liquid) equilibrium (LLE) studies for the extraction of aromatics from alkanes present in the petroleum fractions are important to develop theoretical/semiempirical (liquid + liquid) equilibrium models, which are used in the design of extraction processes. In this work, the ionic liquid 1-ethyl-3-methylimidazolium methylsulfate, [EMim][MSO 4 ], was evaluated as potential solvent for the separation of toluene from heptane and cyclohexane. The LLE data for the quaternary system {heptane (1) + cyclohexane (2) + toluene (3) + [EMim][MSO 4 ] (4)} were experimentally determined at T = 298.15 K and atmospheric pressure. Moreover, the LLE data for the ternary systems {heptane or cyclohexane (1) + toluene (2) + [EMim][MSO 4 ] (3)} were also determined. Solute distribution ratios and selectivities were calculated and analysed in order to evaluate the capability of the ionic liquid to accomplish the separation target. A comparison between the solute distribution ratios and selectivities for the quaternary and the ternary systems was also made. Finally, the experimental tie-line data were correlated with the NRTL model

Polarizability effects on the structure and dynamics of ionic liquids

Energy Technology Data Exchange (ETDEWEB)

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

2014-04-14

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

Parametric study for the optimization of ionic liquid pretreatment of corn stover

Energy Technology Data Exchange (ETDEWEB)

Papa, Gabriella [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Feldman, Taya [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Sandia National Lab. (SNL-CA), Livermore, CA (United States); Sale, Kenneth L. [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Sandia National Lab. (SNL-CA), Livermore, CA (United States); Adani, Fabrizio [Univ. degli Studi di Milano (Italy); Singh, Seema [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Sandia National Lab. (SNL-CA), Livermore, CA (United States); Simmons, Blake A. [Joint BioEnergy Inst. (JBEI), Emeryville, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2017-05-30

A parametric study of the efficacy of the ionic liquid (IL) pretreatment (PT) of corn stover (CS) using 1-ethyl-3-methylimidazolium acetate ([C₂C₁Im][OAc] ) and cholinium lysinate ([Ch][Lys] ) was conducted. The impact of 50% and 15% biomass loading for milled and non-milled CS on IL-PT was evaluated, as well the impact of 20 and 5 mg enzyme/g glucan on saccharification efficiency. The glucose and xylose released were generated from 32 conditions – 2 ionic liquids (ILs), 2 temperatures, 2 particle sizes (S), 2 solid loadings, and 2 enzyme loadings. Statistical analysis indicates that sugar yields were correlated with lignin and xylan removal and depends on the factors, where S did not explain variation in sugar yields. Both ILs were effective in pretreating large particle sized CS, without compromising sugar yields. The knowledge from material and energy balances is an essential step in directing optimization of sugar recovery at desirable process conditions.

Parametric study for the optimization of ionic liquid pretreatment of corn stover.

Science.gov (United States)

Papa, Gabriella; Feldman, Taya; Sale, Kenneth L; Adani, Fabrizio; Singh, Seema; Simmons, Blake A

2017-10-01

A parametric study of the efficacy of the ionic liquid (IL) pretreatment (PT) of corn stover (CS) using 1-ethyl-3-methylimidazolium acetate ([C 2 C 1 Im][OAc]) and cholinium lysinate ([Ch][Lys]) was conducted. The impact of 50% and 15% biomass loading for milled and non-milled CS on IL-PT was evaluated, as well the impact of 20 and 5mg enzyme/g glucan on saccharification efficiency. The glucose and xylose released were generated from 32 conditions - 2 ionic liquids (ILs), 2 temperatures, 2 particle sizes (S), 2 solid loadings, and 2 enzyme loadings. Statistical analysis indicates that sugar yields were correlated with lignin and xylan removal and depends on the factors, where S did not explain variation in sugar yields. Both ILs were effective in pretreating large particle sized CS, without compromising sugar yields. The knowledge from material and energy balances is an essential step in directing optimization of sugar recovery at desirable process conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Structural Changes of Bagasse dusring the Homogeneous Esterification with Maleic Anhydride in Ionic Liquid 1-Allyl-3-methylimidazolium Chloride

Directory of Open Access Journals (Sweden)

Huihui Wang

2018-04-01

Full Text Available The maleation of bagasse could greatly increase the compatibility between bagasse and composite matrixes, and the percentage of substitution (PS of bagasse maleates could be regulated in the homogeneous system. However, due to the complicated components and the linkages of bagasse, it was difficult to control the reaction behaviors of each component. In this paper, the detailed structural changes of bagasse during the homogeneous maleation in ionic liquid 1-allyl-3-methylimidazolium chloride (AmimCl were comparatively investigated with the three main components (cellulose, hemicelluloses, and lignin from bagasse. The PS of the maleated bagasse was 12.52%, and the PS of the maleated cellulose, hemicelluloses, and lignin were 13.50%, 10.89%, and 14.03%, respectively. Fourier translation infrared (FT-IR and NMR analyses confirmed that the three main components were all involved in the homogeneous maleation. 1H-13C HSQC analysis indicated that the predominant monoesterification of cellulose, diesterification of hemicelluloses and lignin, and the degradation of the three main components simultaneously occurred. Besides, the quantitative analysis from 1H-13C HSQC revealed the relative PS of reactive sites in each component. 31P NMR results showed that the reactivity of lignin aliphatic hydroxyls was higher than that of phenolic ones, and the reactivity of phenolic hydroxyls followed the order of p-hydroxyphenyl hydroxyls > guaiacyl hydroxyls > syringyl hydroxyls.

Continuous fixed-bed gas-phase hydroformylation using supported ionic liquid-phase (SILP) Rh catalysts

DEFF Research Database (Denmark)

Riisager, Anders; Wasserscheid, Peter; Van Hal, R.

2003-01-01

Continuous flow gas-phase hydroformylation of propene was performed using novel supported ionic liquid-phase (SILP) catalysts containing immobilized Rh complexes of the biphosphine ligand sulfoxantphos in the ionic liquids 1-n-butyl-3-methylimidazolium hexafluorophosphate and halogen-free 1-n-butyl...

Performance of solid state supercapacitors based on polymer electrolytes containing different ionic liquids

Science.gov (United States)

Tiruye, Girum Ayalneh; Muñoz-Torrero, David; Palma, Jesus; Anderson, Marc; Marcilla, Rebeca

2016-09-01

Four Ionic Liquid based Polymer Electrolytes (IL-b-PE) were prepared by blending a Polymeric Ionic Liquid, Poly(diallyldimethylammonium) bis(trifluoromethanesulfonyl)imide (PILTFSI), with four different ionic liquids: 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR14TFSI) (IL-b-PE1), 1-butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide (PYR14FSI) (IL-b-PE2), 1-(2-hydroxy ethyl)-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (HEMimTFSI) (IL-b-PE3), and 1-Butyl-1-methylpyrrolidinium dicyanamide, (PYR14DCA) (IL-b-PE4). Physicochemical properties of IL-b-PE such as ionic conductivity, thermal and electrochemical stability were found to be dependent on the IL properties. For instance, ionic conductivity was significantly higher for IL-b-PE2 and IL-b-PE4 containing IL with small size anions (FSI and DCA) than IL-b-PE1 and IL-b-PE3 bearing IL with bigger anion (TFSI). On the other hand, wider electrochemical stability window (ESW) was found for IL-b-PE1 and IL-b-PE2 having ILs with electrochemically stable pyrrolidinium cation and FSI and TFSI anions. Solid state Supercapacitors (SCs) were assembled with activated carbon electrodes and their electrochemical performance was correlated with the polymer electrolyte properties. Best performance was obtained with SC having IL-b-PE2 that exhibited a good compromise between ionic conductivity and electrochemical window. Specific capacitance (Cam), real energy (Ereal) & real power densities (Preal) as high as 150 F g-1, 36 Wh kg-1 & 1170 W kg-1 were found at operating voltage of 3.5 V.

Ionic liquids in proton exchange membrane fuel cells: Efficient systems for energy generation

Energy Technology Data Exchange (ETDEWEB)

Padilha, Janine C.; Basso, Juliana; da Trindade, Leticia G.; Martini, Emilse M.A.; de Souza, Michele O.; de Souza, Roberto F. [Institute of Chemistry, UFRGS, Av. Bento Goncalves 9500, Porto Alegre 91501-970, P.O. Box 15003 (Brazil)

2010-10-01

Proton exchange membrane fuel cells (PEMFCs) are used in portable devices to generate electrical energy; however, the efficiency of the PEMFC is currently only 40%. This study demonstrates that the efficiency of a PEMFC can be increased to 61% when 1-butyl-3-methylimidazolium tetrafluoroborate (BMI.BF{sub 4}) ionic liquid (IL) is used together with the membrane electrode assembly (MEA). The results for ionic liquids (ILs) 1-butyl-3-methylimidazolium chloride (BMI.Cl) and 1-butyl-3-methylimidazolium tetrafluoroborate (BMI.BF{sub 4}) in aqueous solutions are better than those obtained with pure water. The current and the power densities with IL are at least 50 times higher than those obtained for the PEMFC wetted with pure water. This increase in PEMFC performance can greatly facilitate the use of renewable energy sources. (author)

Rotational diffusion of nonpolar and ionic solutes in 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imides: is solute rotation always influenced by the length of the alkyl chain on the imidazolium cation?

Science.gov (United States)

Gangamallaiah, V; Dutt, G B

2012-10-25

In an attempt to find out whether the length of the alkyl chain on the imidazolium cation has a bearing on solute rotation, temperature-dependent fluorescence anisotropies of three structurally similar solutes have been measured in a series of 1-alkyl-3-methylimidazolium (alkyl = methyl, ethyl, propyl, butyl, and hexyl) bis(trifluoromethylsulfonyl)imides. Solute-solvent coupling constants obtained from the experimentally measured reorientation times with the aid of Stokes-Einstein-Debye hydrodynamic theory indicate that there is no influence of the length of the alkyl chain on the rotation of nonpolar, anionic, and cationic solutes 9-phenylanthracene (9-PA), fluorescein (FL), and rhodamine 110 (R110), respectively. It has also been noticed that the rotational diffusion of 9-PA is closer to the predictions of slip hydrodynamics, whereas the rotation of negatively charged FL and positively charged R110 is almost identical and follows stick hydrodynamics in these ionic liquids. Despite having similar shape and size, ionic solutes rotate slower by a factor of 3-4 compared to the nonpolar solute. Interplay of specific and electrostatic interactions between FL and the imidazolium cation of the ionic liquids, and between R110 and the bis(trifluoromethylsulfonyl)imide anion, appear to be responsible for the observed behavior. These results are an indication that the length of the alkyl chain on the imidazolium cation does not alter their physical properties in a manner that has an effect on solute rotation.

The Effect of Microporous Polymeric Support Modification on Surface and Gas Transport Properties of Supported Ionic Liquid Membranes.

Science.gov (United States)

Akhmetshina, Alsu A; Davletbaeva, Ilsiya M; Grebenschikova, Ekaterina S; Sazanova, Tatyana S; Petukhov, Anton N; Atlaskin, Artem A; Razov, Evgeny N; Zaripov, Ilnaz I; Martins, Carla F; Neves, Luísa A; Vorotyntsev, Ilya V

2015-12-30

Microporous polymers based on anionic macroinitiator and toluene 2,4-diisocyanate were used as a support for 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF₆]) and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([emim][Tf₂N]) immobilization. The polymeric support was modified by using silica particles associated in oligomeric media, and the influence of the modifier used on the polymeric structure was studied. The supported ionic liquid membranes (SILMs) were tested for He, N₂, NH₃, H₂S, and CO₂ gas separation and ideal selectivities were calculated. The high values of ideal selectivity for ammonia-based systems with permanent gases were observed on polymer matrixes immobilized with [bmim][PF₆] and [emim][Tf₂N]. The modification of SILMs by nanosize silica particles leads to an increase of NH₃ separation relatively to CO₂ or H₂S.

Pretreatment of Oil Palm Frond (OPF) with Ionic Liquid

Science.gov (United States)

Azmi, I. S.; Azizan, A.; Salleh, R. Mohd

2018-05-01

Pretreatment is the key to unlock the recalcitrance of lignocellulose for cellulosic biofuel production. Increasing attention has been drawn to ionic liquids (ILs) for pretreatment of lignocellulosic biomass because this approach was considered as a green engineering method over other conventional methods. In this work, Oil palm frond (OPF) was pretreated by using the ionic liquid 1-ethyl-3-methylimidazolium acetate [EMIM] Ac at the temperature of 99˚C for 3 hours. The characterization of the untreated and pretreated OPF was conducted by using different techniques which are Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The pretreatment of OPF with [EMIM] Ac was demonstrated to be effective evidenced by the significant reduction of Lateral Order Index (LOI) from FTIR, reduction of Crystallinity Index (CI) based on XRD and the significant morphology changes indicated by SEM. The CI value for the pretreated OPF decreased from 0.47 (untreated sample) to 0.28 while the LOI value decreased from 1.10 to 0.24 after pretreatment with [EMIM]Ac and the SEM morphology showed that the pretreated OPF becomes distorted and disordered.

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

Science.gov (United States)

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

2017-10-27

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

Enhanced CO2 capture in binary mixtures of 1-alkyl-3-methylimidazolium tricyanomethanide ionic liquids with water.

Science.gov (United States)

Romanos, George E; Zubeir, Lawien F; Likodimos, Vlassis; Falaras, Polycarpos; Kroon, Maaike C; Iliev, Boyan; Adamova, Gabriela; Schubert, Thomas J S

2013-10-10

Absorption of carbon dioxide and water in 1-butyl-3-methylimidazoliun tricyanomethanide ([C4C1im][TCM]) and 1-octyl-3-methylimidazolium tricyanomethanide ([C8C1im][TCM]) ionic liquids (ILs) was systematically investigated for the first time as a function of the H2O content by means of a gravimetric system together with in-situ Raman spectroscopy, excess molar volume (V(E)), and viscosity deviation measurements. Although CO2 absorption was marginally affected by water at low H2O molar fractions for both ILs, an increase of the H2O content resulted in a marked enhancement of both the CO2 solubility (ca. 4-fold) and diffusivity (ca. 10-fold) in the binary [C(n)C1im][TCM]/H2O systems, in contrast to the weak and/or detrimental influence of water in most physically and chemically CO2-absorbing ILs. In-situ Raman spectroscopy on the IL/CO2 systems verified that CO2 is physically absorbed in the dry ILs with no significant effect on their structural organization. A pronounced variation of distinct tricyanomethanide Raman modes was disclosed in the [C(n)C1im][TCM]/H2O mixtures, attesting to the gradual disruption of the anion-cation coupling by the hydrogen-bonded water molecules to the [TCM](-) anions, in accordance with the positive excess molar volumes and negative viscosity deviations for the binary systems. Most importantly, CO2 absorption in the ILs/H2O mixtures at high water concentrations revealed that the [TCM](-) Raman modes tend to restore their original state for the heavily hydrated ILs, in qualitative agreement with the intriguing nonmonotonous transients of CO2 absorption kinetics unveiled by the gravimetric measurements for the hybrid solvents. A molecular exchange mechanism between CO2 in the gas phase and H2O in the liquid phase was thereby proposed to explain the enhanced CO2 absorption in the hybrid [C(n)C1im][TCM]//H2O solvents based on the subtle competition between the TCM-H2O and TCM-CO2 interactions, which renders these ILs very promising for CO2

Importance of poly(ethylene oxide)-modification and chloride anion for the electron transfer reaction of cytochrome c in 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide

International Nuclear Information System (INIS)

Ohno, Hiroyuki; Suzuki, Chiiko; Fujita, Kyoko

2006-01-01

Horse heart cytochrome c (cyt c) was chemically modified with poly(ethylene oxide) (PEO) to dissolve it in room temperature ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([emim][TFSI]). The redox response of the modified cyt c, hereafter PEO-cyt c, was analyzed in [emim][TFSI]. PEO modification to the surface of cyt c, which exceeded 60% of the total mass of the PEO-cyt c, was an effective method to solubilize the cyt c. In spite of the high ion density and sufficient ionic conductivity of [emim][TFSI], no redox response of pure PEO-cyt c was detected. However, a reversible redox response of PEO-cyt c was observed after adding a simple electrolyte such as KCl to [emim][TFSI]. The redox response of PEO-cyt c was sensitive to the anion radius of the added salt, and the chloride anion was found to be the best anion species to produce a redox response of PEO-cyt c in [emim][TFSI]. However, above a certain salt concentration, the resulting increase in solution viscosity would suppress the redox reaction. The results strongly indicate that the chloride anions, because of their mobility in the polypeptide matrix, compensate the charge change of heme during the electron transfer reaction. Larger anions did not show such an effect due to sterical restrictions on the migration through the protein shell to the heme pocket of cyt c

Electrochemical behavior of ruthenium (III), rhodium (III) and palladium (II) in 1-butyl-3-methylimidazolium chloride ionic liquid

Energy Technology Data Exchange (ETDEWEB)

Jayakumar, M.; Venkatesan, K.A. [Fuel Chemistry Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India); Srinivasan, T.G. [Fuel Chemistry Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India)], E-mail: tgs@igcar.gov.in; Vasudeva Rao, P.R. [Fuel Chemistry Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India)

2009-11-01

Electrochemical behavior of ruthenium (III), rhodium (III) and palladium (II) in 1-butyl-3-methylimidazolium chloride (bmimCl) and their ternary and binary solutions in bmimCl was studied at various working electrodes at 373 K by cyclic voltammetry and chronoamperometry. Ruthenium (III) chloride forms a stable solution with bmimCl and the cyclic voltammogram of ruthenium (III) in bmimCl recorded at glassy carbon electrode consisted of several redox waves due to the complex nature of ruthenium to exist in several oxidation states. Electrolysis of ruthenium (III) chloride in bmimCl at the cathodic limit of bmimCl (-1.8 V (vs. Pd)) did not result in ruthenium metal deposition. However, it was deposited from bmimPF{sub 6} and bmimNTf{sub 2} room temperature ionic liquids at -0.8 V (vs. Pd). The electrochemical behavior of ruthenium (III) in bmimCl in the presence of palladium (II) and rhodium (III) was studied by cyclic voltammetry. The presence of palladium (II) in bmimCl favors underpotential deposition of ruthenium metal. The nuclear loop at -0.5 V (vs. Pd) was observed in all solutions when palladium (II) co-existed with other two metal ions. Nucleation and growth of the metal on glassy carbon working electrode was investigated by chronoamperometry. The growth and decay of chronocurrents has been found to follow the instantaneous nucleation model with three-dimensional growth of nuclei.

Electrochemical performance of microporous and mesoporous activated carbons in neat and diluted 1-ethyl-3-methylimidazolium tetrafluoroborate

Science.gov (United States)

Kumagai, Seiji; Hatomi, Masaki; Tashima, Daisuke

2017-03-01

1-Ethyl-3-methylimidazolium tetrafluoroborate (EMIm·BF4), neat and diluted with propylene carbonate to 1 mol L-1, have been employed as electrolytes of electrical double-layer capacitors (EDLCs). The effects of microporosity and mesoporosity in activated carbon (AC) electrodes on the capacitive and resistive performances upon the use of neat and diluted EMIm·BF4 have been explored. In addition to cyclic voltammetry and galvanostatic charge-discharge tests, electrochemical impedance spectroscopy has been performed employing Kang's equivalent circuit model consisting of three resistances, three constant phase elements, and one bounded Warburg impedance. The overall impedance of the EDLC cell was separated into components of intrinsic resistance, bulk electrolyte, diffusion layer, and Helmholtz layer. The specific capacitance and the equivalent series resistance (ESR) of mesoporous AC were found to be highly dependent on the rate of ionic transfer. Lower cell voltage was identified as being responsible for lower specific capacitance and larger ESR of mesoporous AC, which was similarly seen in the neat and diluted EMIm·BF4, and could be alleviated by increasing the cell voltage. The inferior rate performance and the cell-voltage-dependent performance of mesoporous AC, which were more distinctly observed in the neat EMIm·BF4, could be attributed to the lower mobility of EMIm+ and BF4- in mesopores.

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

International Nuclear Information System (INIS)

Sadeghi, Rahmat; Shekaari, Hemayat; Hosseini, Rahim

2009-01-01

The alkyl chain length of 1-alkyl-3-methylimidazolium bromide ([Rmim][Br], R = propyl (C 3 ), hexyl (C 6 ), heptyl (C 7 ), and octyl (C 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 -1 were taken. The values of the compressibilities, expansivity and apparent molar properties for [C 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

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.

Solid phase extraction of cadmium on 2-mercaptobenzothiazole loaded on sulfur powder in the medium of ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate and cold vapor generation-atomic absorption spectrometric determination

International Nuclear Information System (INIS)

Pourreza, N.; Ghanemi, K.

2010-01-01

A novel solid phase extractor for preconcentration of cadmium at ng L -1 levels has been developed. Cadmium ions were retained on a column packed with sulfur powder modified with 2-mercaptobenzothiazole (2-MBT) in the medium of 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim] + PF 6 - ) ionic liquid. The presence of ionic liquid during modification of sulfur enhanced the retention of cadmium ions on the column. The retained cadmium ions were eluted with 2 mol L -1 solution of HCl and measured by cold vapor generation-atomic absorption spectrometry (CVG-AAS). By using reaction cell-gas liquid separator (RC-GLS), gaseous cadmium vapors were produced and reached the atomic absorption spectrometer, instantaneously. The influence of different variables on both processes of solid phase extraction and CVG-AAS determination of cadmium ions was investigated. The calibration curve was linear in the range of 10-200 ng L -1 of cadmium in the initial solution with r = 0.9992 (n = 8) under optimum conditions. The limit of detection based on three times the standard deviation of the blank (3S b , n = 10) was 4.6 ng L -1 . The relative standard deviation (R.S.D.) of 25 and 150 ng L -1 of cadmium was 4.1 and 2.2% (n = 8), respectively. The procedure was validated by the analysis of a certified reference material (DORM-3), water and fish samples.

Indium triflate in 1-isobutyl-3-methylimidazolium dihydrogenphosphate: an efficient and green catalytic system for Friedel-Crafts acylation

DEFF Research Database (Denmark)

Tran, Phuong Hoang; Hoang, Huy Manh; Chau, Duy-Khiem Nguyen

2015-01-01

Indium triflate in the ionic liquid, 1-isobutyl-3-methylimidazolium dihydrogen phosphate ([i-BMIM]H2PO4), was found to show enhanced catalytic activity in the Friedel–Crafts acylation of various aromatic compounds with acid anhydrides. The catalytic system was easily recovered and reused without...

Imidazolium-based ionic liquids used as additives in the nanolubrication of silicon surfaces

Directory of Open Access Journals (Sweden)

Patrícia M. Amorim

2017-09-01

Full Text Available In recent years, with the development of micro/nanoelectromechanical systems (MEMS/NEMS, the demand for efficient lubricants of silicon surfaces intensified. Although the use of ionic liquids (ILs as additives to base oils in the lubrication of steel/steel or other types of metal/ metal tribological pairs has been investigated, the number of studies involving Si is very low. In this work, we tested imidazolium-based ILs as additives to the base oil polyethylene glycol (PEG to lubricate Si surfaces. The friction coefficients were measured in a nanotribometer. The viscosity of the PEG + IL mixtures as well as their contact angles on the Si surface were measured. The topography and chemical composition of the substrates surfaces were determined with atomic force microscopy (AFM and X-ray photoelectron spectroscopy (XPS, respectively. Due to the hygroscopic properties of PEG, the first step was to assess the effect of the presence of water. Then, a series of ILs based on the cations 1-ethyl-3-methylimidazolium [EMIM], 1-butyl-3-methylimidazolium [BMIM], 1-ethyl-3-vinylimidazolium [EVIM], 1-(2-hydroxyethyl-3-methylimidazolium [C2OHMIM] and 1-allyl-3-methylimidazolium [AMIM] combined with the anions dicyanamide [DCA], trifluoromethanesulfonate [TfO], and ethylsulfate [EtSO4] were added to dry PEG. All additives (2 wt % led to a decrease in friction coefficient as well as an increase in viscosity (with the exception of [AMIM][TfO] and improved the Si wettability. The additives based on the anion [EtSO4] exhibited the most promising tribological behavior, which was attributed to the strong interaction with the Si surface ensuring the formation of a stable surface layer, which hinders the contact between the sliding surfaces.

Ionic Liquid-Tethered Nanoparticle Suspensions: A Novel Class of Ionogels

KAUST Repository

Moganty, Surya S.; Srivastava, Samanvaya; Lu, Yingying; Schaefer, Jennifer L.; Rizvi, Salmaan A.; Archer, Lynden A.

2012-01-01

We report a novel class of silica ionogels created by dispersing silica nanoparticles densely grafted with the ionic liquid (IL) 1-trimethoxysilyl propyl-3-methyl-imidazolium bis- (trifluoromethylsulfonyl) imide (SpmImTSFI) in a 1-butyl-3- methyl

Green synthesis of 2,3,4,9-tetrahydro-1H-carbazoles/ 2,3-dimethylindoles catalyzed by [bmim (BF 4] ionic liquid in methanol

Directory of Open Access Journals (Sweden)

Tamatakallu O. Shrungesh Kumar

2013-03-01

Full Text Available 1-butyl-3-methylimidazolium tetrafluoroborate [bmim (BF 4] ionic liquid has been used as catalyst for the synthesis of tetrahydrocarbazoles and 2, 3-dimethylindoles with excellent yields in a shorter reaction time. The results show that the [bmim (BF 4] ionic liquid is very efficient in the Fischer indole synthesis due to its operational simplicity, high yields, dual catalyst-solvent properties and reused for five consecutive reactions without significant loss of catalytic efficiency. The applicability of the methodology for large-scale reaction highlights its potentiality for industrial scale synthesis. The main advantage of this procedure is that the products could be obtained in pure form after filtration and evaporation of MeOH solvent.

Toward the Elucidation of the Competing Role of Evaporation and Thermal Decomposition in Ionic Liquids: A Multitechnique Study of the Vaporization Behavior of 1-Butyl-3-methylimidazolium Hexafluorophosphate under Effusion Conditions.

Science.gov (United States)

Volpe, V; Brunetti, B; Gigli, G; Lapi, A; Vecchio Ciprioti, S; Ciccioli, A

2017-11-16

The evaporation/decomposition behavior of the imidazolium ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMImPF 6 ) was investigated in the overall temperature range 425-551 K by means of the molecular-effusion-based techniques Knudsen effusion mass loss (KEML) and Knudsen effusion mass spectrometry (KEMS), using effusion orifices of different size (from 0.2 to 3 mm in diameter). Specific effusion fluxes measured by KEML were found to depend markedly on the orifice size, suggesting the occurrence of a kinetically delayed evaporation/decomposition process. KEMS experiments revealed that other species are present in the vapor phase besides the intact ion pair BMImPF 6 (g) produced by the simple evaporation BMImPF 6 (l) = BMImPF 6 (g), with relative abundances depending on the orifice size-the larger the orifice, the larger the contribution of the BMImPF 6 (g) species. By combining KEML and KEMS results, the conclusion is drawn that in the investigated temperature range, when small effusion orifices are used, a significant part of the mass loss/volatility of BMImPF 6 is due to molecular products formed by decomposition/dissociation processes rather than to evaporated intact ion pairs. Additional experiments performed by nonisothermal thermogravimetry-differential thermal analysis (TG-DTA) further support the evidence of simultaneous evaporation/decomposition, although the conventional decomposition temperature derived from TG curves is much higher than the temperatures covered in effusion experiments. Partial pressures of the BMImPF 6 (g) species were derived from KEMS spectra and analyzed by second- and third-law methods giving a value of Δ evap H 298K ° = 145.3 ± 2.9 kJ·mol -1 for the standard evaporation enthalpy of BMImPF 6 . A comparison is done with the behavior of the 1-butyl-3-methylimidazolium bis(trifluoromethyl)sulfonylimide (BMImNTf 2 ) ionic liquid.

Lipid extraction from microalgae using a single ionic liquid

Science.gov (United States)

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

2013-05-28

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

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

Science.gov (United States)

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

2012-09-01

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

Effect of Side Chain Functional Group on Interactions in Ionic Liquid Systems: Insights from Infinite Dilution Thermodynamic Data.

Science.gov (United States)

Paduszyński, Kamil; Królikowska, Marta

2017-11-02

Measurements of infinite dilution activity coefficients of 48 molecular solutes (including alkanes, alkenes, alkynes, aromatics, ethers, alcohols, water, ketones, pyridine, thiophene, acetonitrile, and 1-nitropropane) in two ionic liquids (ILs), namely, 1-(2-hydroxyethyl)-3-methylimidazolium dicyanamide and 1-(2-chloroethyl)-3-methylimidazolium dicyanamide, are reported in the temperature range from T = 308.15 to 358.15 K. Comparative analysis of an effect of OH/Cl substitution of terminal carbon in side chains of imidazolium cations is presented and discussed in terms of different types of intermolecular forces acting between ILs and solutes. The new data also are confronted to those published previously for a "plain" counterpart of the studied ILs, namely, 1-ethyl-3-methylimidazolium dicyanamide. Infinite dilution capacity and selectivity of the studied ILs are presented to evaluate them as separating agents in extraction of aromatics from alkanes and sulfur compounds from alkanes. Three modeling approaches, namely, linear solvation energy relationship (LSER), regular solution theory, and conductor-like screening model for real solvents (COSMO-RS), are tested for their capabilities of capturing the substitution effects detected experimentally.

Simple ionic-liquid assisted method for preparation of Cd{sub 1-x} Zn{sub x}S nanoparticles with improved photocatalytic activity

Energy Technology Data Exchange (ETDEWEB)

Naghiloo, Samira; Habibi-Yangjeh, Aziz [Mohaghegh Ardabili Univ. (Iran, Islamic Republic of). Dept. of Chemistry; Behboudnia, Mahdi [Urmia Univ. of Technolgy (Iran, Islamic Republic of). Dept. of Physics

2012-12-15

Nanoparticles of Cd{sub 1-x} Zn{sub x}S (x=0-0.8) were prepared in neat 1-ethyl-3-methylimidazolium ethyl sulfate, a halide-free and low-cost room-temperature ionic liquid (RTIL) via a simple heating method. The nanoparticles were investigated by means of powder X-ray diffraction, scanning electron microscopy, and UV-Vis diffuse reflectance spectroscopy techniques. The diffraction patterns demonstrate that the prepared nanoparticles in the RTIL have smaller size relative to the samples prepared in water. The photocatalytic activities of the nanoparticles towards photodegradation of methylene blue were evaluated under UV and visible irradiation. The results indicate that the nanoparticles prepared in the RTIL have greater photocatalytic activity relative to the samples prepared in water. The reaction rate constant under visible light irradiation on the nanoparticles prepared in the RTIL is at least six times greater than for the samples prepared in water. (orig.)

An Efficient Process for Pretreatment of Lignocelluloses in Functional Ionic Liquids

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Shi-Jia Dong

2015-01-01

Full Text Available Background and Aims. The complex structure of the lignocelluloses is the main obstacle in the conversion of lignocellulosic biomass into valuable products. Ionic liquids provide the opportunities for their efficient pretreatment for biomass. Therefore, in this work, pretreatment of corn stalk was carried out in ultrasonic-assisted ionic liquid including 1-butyl-3-methylimidazolium chloride [BMIM]Cl, 1-H-3-methylimidazolium chloride [HMIM]Cl, and 1-(1-propylsulfonic-3-imidazolium chloride [HSO3-pMIM]Cl at 70°C for 2 h. We compared the pretreatments by ionic liquid with and without the addition of deionized water. Fourier transform infrared spectroscopy (FTIR and scanning electron microscopy (SEM were employed to analyze the chemical characteristics of regenerated cellulose-rich materials. Results. [HMIM]Cl and [HSO3-pMIM]Cl were effective in lignin extraction to obtain cellulose-rich materials. FTIR analysis and SEM analysis indicated the effective lignin removal and the reduced crystallinity of cellulose-rich materials. Enzymatic hydrolysis of cellulose-rich materials was performed efficiently. High yields of reducing sugar and glucose were obtained when the corn stalk was pretreated by [HMIM]Cl and [HSO3-pMIM]Cl. Conclusions. Ionic liquids provided the ideal environment for lignin extraction and enzymatic hydrolysis of corn stalk and [HMIM]Cl and [HSO3-pMIM]Cl proved the most efficient ionic liquids. This simple and environmentally acceptable method has a great potential for the preparation of bioethanol for industrial production.

Investigation of the interactions between 1-butyl-3-methylimidazolium-based ionic liquids and isobutylene using density functional theory.

Science.gov (United States)

Li, Xiaoning; Guo, Wenli; Wu, Yibo; Li, Wei; Gong, Liangfa; Zhang, Xiaoqian; Li, Shuxin; Shang, Yuwei; Yang, Dan; Wang, Hao

2018-03-06

To identify ionic liquids (ILs) that could be used as solvents in isobutylene (IB) polymerization, the interactions between IB and eight different ILs based on the 1-butyl-3-methylimidazolium cation ([Bmim] + ) were investigated using density functional theory (DFT). The anions in the ILs were chloride, hexafluorophosphate, tetrafluoroborate, bis[(trifluoromethyl)sulfonyl]imide, tetrachloroaluminate ([AlCl 4 ] - ), tetrachloroferrate, acetate, and trifluoroacetate. The interaction geometries were explained by changes in the total energy, intermolecular distances, Hirshfeld charges, and the electrostatic potential surface. The IL solvents were screened by comparing their interaction intensities with IB to the interaction intensities of reference ILs ([AlCl 4 ] - -based ILs) with IB. The microscopic mechanism for IB dissolution was rationalized by invoking a previously reported microscopic mechanism for the dissolution of gases in ILs. Computation results revealed that hydrogen (H) bonding between C2-H on the imidazolium ring and the anions plays a key role in ion pair (IP) formation. The addition of IB leads to slight changes in the dominant interactions of the IP. IB molecules occupied cavities created by small angular rearrangements of the anions, just as CO 2 does when it is dissolved in an IL. The limited total free space in the ILs and the much larger size of IB than CO 2 were found to be responsible for the poor solubility of IB compared with that of CO 2 in the ILs.

All-solid-state flexible supercapacitors based on papers coated with carbon nanotubes and ionic-liquid-based gel electrolytes

International Nuclear Information System (INIS)

Kang, Yu Jin; Kim, Woong; Chung, Haegeun; Han, Chi-Hwan

2012-01-01

All-solid-state flexible supercapacitors were fabricated using carbon nanotubes (CNTs), regular office papers, and ionic-liquid-based gel electrolytes. Flexible electrodes were made by coating CNTs on office papers by a drop-dry method. The gel electrolyte was prepared by mixing fumed silica nanopowders with ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][NTf 2 ]). This supercapacitor showed high power and energy performance as a solid-state flexible supercapacitor. The specific capacitance of the CNT electrodes was 135 F g −1 at a current density of 2 A g −1 , when considering the mass of active materials only. The maximum power and energy density of the supercapacitors were 164 kW kg −1 and 41 Wh kg −1 , respectively. Interestingly, the solid-state supercapacitor with the gel electrolyte showed comparable performance to the supercapacitors with ionic-liquid electrolyte. Moreover, the supercapacitor showed excellent stability and flexibility. The CNT/paper- and gel-based supercapacitors may hold great potential for low-cost and high-performance flexible energy storage applications. (paper)

Thermoelectric energy recovery at ionic-liquid/electrode interface

Energy Technology Data Exchange (ETDEWEB)

Bonetti, Marco; Nakamae, Sawako; Huang, Bo Tao; Wiertel-Gasquet, Cécile; Roger, Michel [Service de Physique de l’Etat Condensé, CEA-IRAMIS-SPEC, CNRS-UMR 3680, CEA Saclay, F-91191 Gif-sur-Yvette Cedex (France); Salez, Thomas J. [Service de Physique de l’Etat Condensé, CEA-IRAMIS-SPEC, CNRS-UMR 3680, CEA Saclay, F-91191 Gif-sur-Yvette Cedex (France); École des Ponts ParisTech, 6 et 8 avenue Blaise Pascal, Champs-sur-Marne, F-77455 Marne-la-Vallée (France)

2015-06-28

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

Optimization of oligomeric enzyme activity in ionic liquids using Rhodotorula glutinis yeast phenylalanine ammonia lyase.

Science.gov (United States)

Barron, Christiaan C; Sponagle, Brandon J D; Arivalagan, Pugazhendhi; D'Cunha, Godwin B

2017-01-01

Phenylalanine ammonia lyase (E.C.4.3.1.24, PAL) activity of Rhodotorula glutinis yeast has been demonstrated in four commonly used ionic liquids. PAL forward reaction was carried out in 1-butyl-3-methylimidazolium methyl sulfate ([BMIM][MeSO 4 ]), 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF 4 ]), 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF 6 ]) and 1-butyl-3-methylimidazolium lactate ([BMIM][lactate]). Our experiments have revealed that PAL is catalytically active in ionic liquids and the enzyme activity in ([BMIM][PF 6 ]) is comparable to that obtained in aqueous buffer medium. Different conditions were optimized for maximal PAL forward activity including time of incubation (30.0min) L -phenylalanine substrate concentration (30.0mM), nature of buffer (50.0mM Tris-HCl), pH (9.0), temperature (37°C), and speed of agitation (100 rev min -1 ). Under these optimized conditions, about 83% conversion of substrate to product was obtained for the PAL forward reaction that was determined using UV spectroscopy at 290nm. PAL reverse reaction in ([BMIM][PF 6 ]) was determined spectrophotometrically at 520nm; and about 59% substrate conversion was obtained. This data provides further knowledge in enzyme biocatalysis in non-aqueous media, and may be of importance when studying the function of other oligomeric/multimeric proteins and enzymes in ionic liquids. Copyright © 2016 Elsevier Inc. All rights reserved.

The Effect of Microporous Polymeric Support Modification on Surface and Gas Transport Properties of Supported Ionic Liquid Membranes

Directory of Open Access Journals (Sweden)

Alsu A. Akhmetshina

2015-12-01

Full Text Available Microporous polymers based on anionic macroinitiator and toluene 2,4-diisocyanate were used as a support for 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6] and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonylimide ([emim][Tf2N] immobilization. The polymeric support was modified by using silica particles associated in oligomeric media, and the influence of the modifier used on the polymeric structure was studied. The supported ionic liquid membranes (SILMs were tested for He, N2, NH3, H2S, and CO2 gas separation and ideal selectivities were calculated. The high values of ideal selectivity for ammonia-based systems with permanent gases were observed on polymer matrixes immobilized with [bmim][PF6] and [emim][Tf2N]. The modification of SILMs by nanosize silica particles leads to an increase of NH3 separation relatively to CO2 or H2S.

Different characteristic effects of ageing on starch-based films plasticised by 1-ethyl-3-methylimidazolium acetate and by glycerol.

Science.gov (United States)

Zhang, Binjia; Xie, Fengwei; Zhang, Tianlong; Chen, Ling; Li, Xiaoxi; Truss, Rowan W; Halley, Peter J; Shamshina, Julia L; McNally, Tony; Rogers, Robin D

2016-08-01

The focus of this study was on the effects of plasticisers (the ionic liquid 1-ethyl-3-methylimidazolium acetate, or [Emim][OAc]; and glycerol) on the changes of starch structure on multiple length scales, and the variation in properties of plasticised starch-based films, during ageing. The films were prepared by a simple melt compression moulding process, followed by storage at different relative humidity (RH) environments. Compared with glycerol, [Emim][OAc] could result in greater homogeneity in [Emim][OAc]-plasticised starch-based films (no gel-like aggregates and less molecular order (crystallites) on the nano-scale). Besides, much weaker starch-starch interactions but stronger starch-[Emim][OAc] interactions at the molecular level led to reduced strength and stiffness but increased flexibility of the films. More importantly, [Emim][OAc] (especially at high content) was revealed to more effectively maintain the plasticised state during ageing than glycerol: the densification (especially in the amorphous regions) was suppressed; and the structural characteristics especially on the nano-scale were stabilised (especially at a high RH), presumably due to the suppressed starch molecular interactions by [Emim][OAc] as confirmed by Raman spectroscopy. Such behaviour contributed to stabilised mechanical properties. Nonetheless, the crystallinity and thermal stability of starch-based films with both plasticisers were much less affected by ageing and moisture uptake during storage (42 days), but mostly depended on the plasticiser type and content. As starch is a typical semi-crystalline bio-polymer containing abundant hydroxyl groups and strong hydrogen bonding, the findings here could also be significant in creating materials from other similar biopolymers with tailored sensitivity and properties to the environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Functional ionic liquids

International Nuclear Information System (INIS)

Baecker, Tobias

2012-01-01

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 V O 2 + compounds. As well, ionic liquids with [FeCl 4 ] - and [Cl 3 FeOFeCl 3 ] 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.

Thermodynamic Description of Liquid-Liquid Equilibria in Systems 1-Ethyl-3-methylimidazolium Ethylsulfate + C7-Hydrocarbons by Polymer-Solution Models

Czech Academy of Sciences Publication Activity Database

Bendová, Magdalena; Wagner, Zdeněk

2009-01-01

Roč. 284, č. 2 (2009), s. 80-85 ISSN 0378-3812 R&D Projects: GA ČR GA104/07/0444; GA ČR GP104/06/P066; GA AV ČR IAA400720710 Institutional research plan: CEZ:AV0Z40720504 Keywords : liquid-liquid equilibrium * ionic liquids * thermodynamic model Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.857, year: 2009

Extraction of butan-1-ol from water with ionic liquids at T = 308.15 K

International Nuclear Information System (INIS)

Domańska, Urszula; Królikowski, Marek

2012-01-01

Highlights: ► The LLE ternary phase diagrams with ionic liquids were measured. ► Separation of butan-1-ol/water system with tetracyanoborate-based ILs. ► Low solubility of water in [P 14,6,6,6 ][TCB] was observed. ► [P 14,6,6,6 ][TCB] is proposed for possible use in separation of butan-1-ol from aqueous phase. - Abstract: Ionic liquids (ILs) are novel green solvents that can be proposed for removing butan-1-ol from the aqueous fermentation media. Ternary (liquid + liquid) equilibrium data are presented for {ionic liquid (1) + butan-1-ol (2) + water (3)} at T = 308.15 K and ambient pressure to analyze the performance of the ionic liquid (IL) in the extraction of butan-1-ol from aqueous phase. The tetracyanoborate-based ILs have been studied: 1-hexyl-3-methylimidazolium tetracyanoborate, ([HMIM][TCB]), 1-decyl-3-methylimidazolium tetracyanoborate, ([DMIM][TCB]) and trihexyltetradecylphosphonium tetracyanoborate, ([P 14,6,6,6 ][TCB]). The results are discussed in terms of the selectivity and distribution ratio of separation of related systems. The complete miscibility in the binary liquid systems of butan-1-ol with all used ILs was observed. The imidazolium cation in comparison with phosphonium cation shows lower selectivity and distribution ratio. The IL with the longer alkyl chain at the cation shows higher selectivity and distribution ratio in this process. The non-random two liquid NRTL model was used successfully to correlate the experimental tie-lines and to calculate the phase composition error in mole fraction in the ternary systems. The average root mean square deviation (RMSD) of the phase composition was 0.0027. The data presented here indicates the usefulness of [P 14,6,6,6 ][TCB] as a solvent for the separation of butan-1-ol from water using solvent extraction. The density of [P 14,6,6,6 ][TCB] was measured as a function of temperature.

Volatility study of [C1C1im][NTf2] and [C2C3im][NTf2] ionic liquids

International Nuclear Information System (INIS)

Rocha, Marisa A.A.; Ribeiro, Filipe M.S.; Schröder, Bernd; Coutinho, João A.P.; Santos, Luís M.N.B.F.

2014-01-01

Highlights: • Vapor pressures of [C 1 C 1 im][NTf 2 ] and [C 2 C 3 im][NTf 2 ] ionic liquids are reported. • [C 1 C 1 im][NTf 2 ] presents higher enthalpy and entropy of vaporization than expected. • The high volatility of [C 2 C 3 im][NTf 2 ] is a result from its asymmetric character. -- Abstract: Vapor pressures of 1,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide, ([C 1 C 1 im][NTf 2 ]) and 1-ethyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide, ([C 2 C 3 im][NTf 2 ]) ionic liquids were measured as a function of temperature using a Knudsen effusion apparatus combined with a quartz crystal microbalance. Enthalpies and entropies of vaporization were derived from the fitting of vapor pressure and temperature results to the Clarke and Glew equation. [C 1 C 1 im][NTf 2 ] presents a higher enthalpy and entropy of vaporization than the neighboring members of the series. The enthalpy of vaporization of [C 2 C 3 im][NTf 2 ] lies in between the asymmetric and symmetric ionic liquid series, reflecting a decrease in the electrostatic interactions due to a decrease of the charge accessibility between the ionic pairs when the methyl group is replaced by an ethyl group. The obtained higher volatility of [C 2 C 3 im][NTf 2 ] arises from its asymmetric character, leading to an higher entropic contribution that compensates the enthalpic penalty. The border conditions ([C 1 C 1 im][NTf 2 ], [C 2 C 1 im][NTf 2 ] and [C 2 C 2 im][NTf 2 ]), topology ([C 2 C 3 im][NTf 2 ]) and symmetry/asymmetry of the ILs effect were evaluated and rationalized based on a comparative analysis of the thermodynamic properties, enthalpies and entropies of vaporization

Proteomic alterations induced by ionic liquids in Aspergillus nidulans and Neurospora crassa.

Science.gov (United States)

Martins, Isabel; Hartmann, Diego O; Alves, Paula C; Planchon, Sébastien; Renaut, Jenny; Leitão, M Cristina; Rebelo, Luís P N; Silva Pereira, Cristina

2013-12-06

This study constitutes the first attempt to understand at the proteomic level the fungal response to ionic liquid stress. Ascomycota are able to grow in media supplemented with high concentrations of an ionic liquid, which, in turn, lead to major alterations in the fungal metabolic footprint. Herein, we analysed the differential accumulation of mycelial proteins in Aspergillus nidulans and Neurospora crassa after their exposure to two of the most commonly used ionic liquids: 1-ethyl-3-methylimidazolium chloride or cholinium chloride. Data obtained showed that numerous stress-responsive proteins (e.g. anti-ROS defence proteins) as well as several critical biological processes and/or pathways were affected by either ionic liquid. Amongst other changes, these compounds altered developmental programmes in both fungi (e.g. promoting the development of Hülle cells or conidiation) and led to accumulation of osmolytes, some of which may play an important role in multiple stress responses. In particular, in N. crassa, both ionic liquids increased the levels of proteins which are likely involved in the biosynthesis of unusual metabolites. These data potentially open new perspectives on ionic liquid research, furthering their conscious design and their use to trigger production of targeted metabolites. The present study emphasises the importance of understanding ionic liquid's stress responses, crucial to further their safe large-scale usage. Knowledge of the alterations prompted at a cellular and biochemical level gives also fresh perspectives on how to employ these "novel" compounds to manipulate proteins or pathways of biotechnological value. The results presented here provide meaningful insights into the understanding of fungi stress and adaptation responses to anthropogenic chemicals used in industry. © 2013.

Finding the best density functional approximation to describe interaction energies and structures of ionic liquids in molecular dynamics studies

Science.gov (United States)

Perlt, Eva; Ray, Promit; Hansen, Andreas; Malberg, Friedrich; Grimme, Stefan; Kirchner, Barbara

2018-05-01

Ionic liquids raise interesting but complicated questions for theoretical investigations due to the fact that a number of different inter-molecular interactions, e.g., hydrogen bonding, long-range Coulomb interactions, and dispersion interactions, need to be described properly. Here, we present a detailed study on the ionic liquids ethylammonium nitrate and 1-ethyl-3-methylimidazolium acetate, in which we compare different dispersion corrected density functional approximations to accurate local coupled cluster data in static calculations on ionic liquid clusters. The efficient new composite method B97-3c is tested and has been implemented in CP2K for future studies. Furthermore, tight-binding based approaches which may be used in large scale simulations are assessed. Subsequently, ab initio as well as classical molecular dynamics simulations are conducted and structural analyses are presented in order to shed light on the different short- and long-range structural patterns depending on the method and the system size considered in the simulation. Our results indicate the presence of strong hydrogen bonds in ionic liquids as well as the aggregation of alkyl side chains due to dispersion interactions.

Benzene and cyclohexane separation using 1-butyl-3-methylimidazolium thiocyanate

Science.gov (United States)

Gonfa, Girma; Ismail, Marhaina; Bustam, Mohamad Azmi

2017-09-01

Cyclohexane is mainly produced by catalytic hydrogenation of benzene. Removal of unreacted benzene from the product stream is very important in this process. However, due to their close boiling points and azeotrope formation, it is very difficult to separate cyclohexane and benzene by conventional distillation. Currently, special separation processes such as processes extractive distillation is commercially used for this separation. However, this extractive distillation suffers from process complexity and higher energy consumption due to their low extractive selectivity of molecular entrainers used. The aim of the present work is to investigate the applicability of ionic liquids as entrainer in extractive distillation of benzene and cyclohexane mixture. In this study, we investigated 1-butyl-3-methylimidazolium thiocyanate ([BMIM][SCN]) ionic liquid for separation of benzene and cyclohexane by measuring the Vapor Liquid Equilibrium data of the two components in the presence of the ionic liquid. As green and potential environmentally friendly solvents, ionic liquids have attracted increasing attention as alternative conventional entrainers in extractive distillation. Isothermal Vapor Liquid Equilibrium for the benzene + cyclohexane + [BMIM][SCN] ternary system was obtained at 353.15 K using a Head Space Gas Chromatography. The addition of [BMIM][SCN] breaks the benzene-cyclohexane azeotrope and increased the relative volatility cyclohexane to benzene in the mixture. The effect of [BMIM][SCN] on the relative volatility cyclohexane to benzene was studied at various benzene and cyclohexane compositions and solvent to feed ratios. The performance of [BMIM][SCN] was compared with typical conventional solvents, dimethylformamide (DMF) and dimethylsulfoxide (DMSO). The results show that the relative volatility of cyclohexane to benzene in the presence of [BMIM][SCN] is higher compared that of DMSO and DMF.

Effect of Structure on Transport Properties (Viscosity, Ionic Conductivity, and Self-Diffusion Coefficient) of Aprotic Heterocyclic Anion (AHA) Room-Temperature Ionic Liquids. 1. Variation of Anionic Species.

Science.gov (United States)

Sun, Liyuan; Morales-Collazo, Oscar; Xia, Han; Brennecke, Joan F

2015-12-03

A series of room temperature ionic liquids (RTILs) based on 1-ethyl-3-methylimidazolium ([emim](+)) with different aprotic heterocyclic anions (AHAs) were synthesized and characterized as potential electrolyte candidates for lithium ion batteries. The density and transport properties of these ILs were measured over the temperature range between 283.15 and 343.15 K at ambient pressure. The temperature dependence of the transport properties (viscosity, ionic conductivity, self-diffusion coefficient, and molar conductivity) is fit well by the Vogel-Fulcher-Tamman (VFT) equation. The best-fit VFT parameters, as well as linear fits to the density, are reported. The ionicity of these ILs was quantified by the ratio of the molar conductivity obtained from the ionic conductivity and molar concentration to that calculated from the self-diffusion coefficients using the Nernst-Einstein equation. The results of this study, which is based on ILs composed of both a planar cation and planar anions, show that many of the [emim][AHA] ILs exhibit very good conductivity for their viscosities and provide insight into the design of ILs with enhanced dynamics that may be suitable for electrolyte applications.

Structure and lifetimes in ionic liquids and their mixtures.

Science.gov (United States)

Gehrke, Sascha; von Domaros, Michael; Clark, Ryan; Hollóczki, Oldamur; Brehm, Martin; Welton, Tom; Luzar, Alenka; Kirchner, Barbara

2018-01-01

With the aid of molecular dynamics simulations, we study the structure and dynamics of different ionic liquid systems, with focus on hydrogen bond, ion pair and ion cage formation. To do so, we report radial distribution functions, their number integrals, and various time-correlation functions, from which we extract well-defined lifetimes by means of the reactive flux formalism. We explore the influence of polarizable force fields vs. non-polarizable ones with downscaled charges (±0.8) for the example of 1-butyl-3-methylimidazolium bromide. Furthermore, we use 1-butyl-3-methylimidazolium trifluoromethanesulfonate to investigate the impact of temperature and mixing with water as well as with the chloride ionic liquid. Smaller coordination numbers, larger distances, and tremendously accelerated dynamics are observed when the polarizable force field is applied. The same trends are found with increasing temperature. Adding water decreases the ion-ion coordination numbers whereas the water-ion and water-water coordination is enhanced. A domain analysis reveals that the nonpolar parts of the ions are dispersed and when more water is added the water clusters increase in size. The dynamics accelerate in general upon addition of water. In the ionic liquid mixture, the coordination number around the cation changes between the two anions, but the number integrals of the cation around the anions remain constant and the dynamics slow down with increasing content of the chloride ionic liquid.

IONIC LIQUID-CATALYZED ALKYLATION OF ISOBUTANE WITH 2-BUTENE

Science.gov (United States)

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

Novel applications of ionic liquids in materials processing

International Nuclear Information System (INIS)

Reddy, Ramana G

2009-01-01

Ionic liquids are mixtures of organic and inorganic salts which are liquids at room temperature. Several potential applications of ionic liquids in the field of materials processing are electrowinning and electrodeposition of metals and alloys, electrolysis of active metals at low temperature, liquid-liquid extraction of metals. Results using 1-butyl-3-methylimidazolium chloride with AlCl 3 at low temperatures yielded high purity aluminium deposits (>99.9% pure) and current efficiencies >98%. Titanium and aluminium were co-deposited with/without the addition of TiCl 4 with up to 27 wt% Ti in the deposit with current efficiencies in the range of 78-85 %. Certain ionic liquids are potential replacements for thermal oils and molten salts as heat transfer fluids in solar energy applications due to high thermal stability, very low corrosivity and substantial sensible heat retentivity. The calculated storage densities for several chloride and fluoride ionic liquids are in the range of 160-210 MJ/m 3 . A 3-D mathematical model was developed to simulate the large scale electrowinning of aluminium. Since ionic liquids processing results in their low energy consumption, low pollutant emissions many more materials processing applications are expected in future.

Comparing Triflate and Hexafluorophosphate Anions of Ionic Liquids in Polymer Electrolytes for Supercapacitor Applications

Directory of Open Access Journals (Sweden)

Chiam-Wen Liew

2014-05-01

Full Text Available Two different ionic liquid-based biopolymer electrolyte systems were prepared using a solution casting technique. Corn starch and lithium hexafluorophosphate (LiPF6 were employed as polymer and salt, respectively. Additionally, two different counteranions of ionic liquids, viz. 1-butyl-3-methylimidazolium hexafluorophosphate (BmImPF6 and 1-butyl-3-methylimidazolium trifluoromethanesulfonate (also known as 1-butyl-3-methylimidazolium triflate (BmImTf were used and studied in this present work. The maximum ionic conductivities of (1.47 ± 0.02 × 10−4 and (3.21 ± 0.01 × 10−4 S∙cm−1 were achieved with adulteration of 50 wt% of BmImPF6 and 80 wt% of BmImTf, respectively at ambient temperature. Activated carbon-based electrodes were prepared and used in supercapacitor fabrication. Supercapacitors were then assembled using the most conducting polymer electrolyte from each system. The electrochemical properties of the supercapacitors were then analyzed. The supercapacitor containing the triflate-based biopolymer electrolyte depicted a higher specific capacitance with a wider electrochemical stability window compared to that of the hexafluorophosphate system.

An efficient binary ionic liquid based quasi solid-state electrolyte for dye-sensitized solar cells

International Nuclear Information System (INIS)

Chen, Junnian; Peng, Tianyou; Shi, Wenye; Li, Renjie; Xia, Jiangbin

2013-01-01

A novel binary ionic liquid electrolyte containing lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) and binary ionic liquids, which is composed of 1-butyl-3-methylimidazolium iodide (BMII) and 1-butyl-3-methylimidazolium thiocyanate (BMISCN), is developed for dye-sensitized solar cells (DSSCs). It is found that incorporation of LiTFSI as charge transfer promoter with BMII has positive effect on the interfacial charge transfer of the dye/TiO 2 film, further addition of BMISCN into the above composite electrolyte can take advantage of its low viscosity to enhance the ionic conductivity and reduce the interfacial charge transfer resistance, and a photovoltaic conversion efficiency of 5.55% is obtained from the solar cell fabricated with the optimized binary ionic liquid electrolyte without iodine participation under AM 1.5 illumination at 100 mW cm −2 , with a 108.6% improvement in the efficiency with lower resistance and higher ionic conductivity as compared to the solar cell fabricated with single BMII ionic liquid-based electrolyte. The above results should be attributed to the reduced charge recombination and the effective interfacial charge transfer in the solar cell

3+ and [Sb13Se16Br2] 5+ - Double and quadruple spiro cubanes from ionic liquids

KAUST Repository

Ahmed, Ejaz; Breternitz, Joachim; Groh, Matthias Friedrich; Isaeva, Anna A.; Ruck, Michael J.

2014-01-01

The reaction of antimony and selenium in the bromine-rich Lewis acidic ionic liquid [BMIm]Br·4.7AlBr3 (BMIm: 1-butyl-3- methylimidazolium) in the presence of a small amount of NbCl5 at 160 °C yielded dark-red crystals of [Sb7Se8Br 2][AlX4]3. For X

Lignin Structure and Aggregation Behavior in a Two-Component Ionic Liquid Solvent System

Directory of Open Access Journals (Sweden)

Susanne Bylin

2014-08-01

Full Text Available Ionic liquids are of potential interest in the processing of lignocellulosic biomass. In this study, the ionic liquid co-solvent system of 1-methylimidazole (MIM and 1-ethyl-3-methyl-imidazolium acetate (EMIMAc was used to solvate LignoBoost lignin fractionated from black liquor obtained from a kraft paper mill. Lignin ethanol-precipitated (LEP and ethanol-soluble (LES fractions were characterized via gel permeation chromatography (GPC and 13C- and 31P-nuclear magnetic resonance spectroscopy (NMR to determine structural characteristics and their relationship to polymer solubility in the system. Polymer integrity and solubility were optimal at ~20% lignin loading (w/w. Results showed that LEPs were generally of higher apparent molecular weight (Mw and enriched with condensed/aliphatic ether linkages and aliphatic hydroxyls. The LESs had a lower apparent Mw and were enriched with carboxylic and phenolic groups. This newly gained knowledge on lignin fractionation and aggregation in the present solvent system provides future opportunities for tuning fractionation/extraction to suit a specific biomass-derived product, e.g., carbon fibers.

Electrochemical Studies on Uranyl Chloride Complexes in 1-Butyl-3-methyl-imidazolium Based Ionic liquids

Energy Technology Data Exchange (ETDEWEB)

Yasuhisa Ikeda; Katsuyuki Hiroe; Nobutaka Ohta; Masanobu Nogami; Atsushi Shirai [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology 2-12-1-N1-34 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan); Noriko Asanuma [Department of Energy Science and Engineering, Tokai University 1117 Kitakaname, Hiratsuka-shi, Kanagawa 259-1292 (Japan)

2008-07-01

Sample solutions were prepared by dissolving UO{sub 2}Cl{sub 2}-nH{sub 2}O or Cs{sub 2}UO{sub 2}Cl{sub 4} into 1-butyl-3-methyl-imidazolium chloride (BMICl). Their UV-visible absorption spectra showed that uranyl species in BMICl exist as [UO{sub 2}Cl{sub 4}]{sup 2-}. Cyclic voltammograms were measured using a glassy carbon working electrode, a platinum wire counter electrode, and an Ag/AgCl reference electrode with a liquid junction filled with BMIBF{sub 4} at 80 {+-} 1 deg. C in glove box under an Ar atmosphere. Peaks of one redox couple were observed at around -0.73 V and -0.65 V on both systems. Potential differences between two peaks ({delta}E{sub p}) at scan rates in the range of 10 to 50 mV/s are 70 - 80 mV, which are almost consistent with theoretical {delta}E{sub p} value (67 mV) for the reversible one electron transfer reaction at 80 deg. C. From these results, it is concluded that [UO{sub 2}Cl{sub 4}]{sup 2-} in BMICl is reduced quasi-reversibly to [UO{sub 2}Cl{sub 4}]{sup 3-}. (authors)

Fundamental study on decontamination of wastes contaminated by uranium fluorides by using ionic liquids - dissolution and electrochemistry of uranium in 1-butyl-3-methylimidazolium chloride

International Nuclear Information System (INIS)

Noriko Asanuma; Yusuke Ohhashi; Yukio Wada; Masayuki Harada; Yasuhisa Ikeda

2008-01-01

Treatment method for wastes contaminated uranium fluorides by using ionic liquids as media of pyrochemical process instead of alkali metal chloride molten salts was proposed. In this method, uranium fluorides such as UF 4 or NaF adsorbing UF 6 are dissolved in 1-butyl-3-methylimidazolium chloride (BMICl) and dissolved uranium species are recovered as deposits by electrochemical reduction. Under the atmospheric condition, UF 4 was completely dissolved in BMICl at 100 deg. C. UV-vis absorption spectra of the sample solution indicated that main species of uranium are U(VI) and a part of uranium exists as U(IV). Chemical form of uranium in the NaF adsorbents is Na 3 UO 2 F 5 . Therefore, it was immediately dissolved to BMICl. However, complete dissolution was not achieved. Cyclic voltammetry of the solutions prepared by dissolution experiments was performed. Redox properties of uranium species in each sample were irreversible. It was assigned to reduction of U(VI) to U(IV). As a result of preliminary bulk electrolysis, it was expected that reduction products are deposited on the carbon cathode. (authors)

Biomass Conversion in Ionic Liquids - in-situ Investigations

DEFF Research Database (Denmark)

Kunov-Kruse, Andreas Jonas

Due to rising oil prices and global warming caused by CO2 emissions, there is an increased demand for new types of fuels and chemicals derived from biomass. This thesis investigates catalytic conversion of cellulose into sugars in ionic liquids and the important platform chemical 5-hydroxymethylf......Due to rising oil prices and global warming caused by CO2 emissions, there is an increased demand for new types of fuels and chemicals derived from biomass. This thesis investigates catalytic conversion of cellulose into sugars in ionic liquids and the important platform chemical 5......-hydroxymethylfurfural (HMF). The thesis focuses on kinetic and mechanistic investigations using new in-situ FTIR spectroscopic methods based on the ATR-principle. At first the kinetics of cellulose hydrolysis and the simultaneously HMF formation was investigated in the ionic liquid 1-butyl-2,3-dimethylimidazolium...... activation energies suggest that the ionic liquid acts co-catalytic by stabilizing the oxocarbenium transition state. The chromium catalyzed conversion of glucose to HMF in ionic liquid 1-butyl-3-methylimidazolium chloride with CrCl3⋅6H2O and CrCl2 as catalysts was investigated. The CrCl3⋅6H2O catalyst...

Raman Spectroscopy and Ab-Initio Model Calculations on Ionic Liquids:Invited Review

OpenAIRE

Berg, Rolf W.

2007-01-01

A review of the recent developments in the study and understanding of room temperature ionic liquids are given. An intimate picture of how and why these liquids are not crystals at ambient conditions is attempted, based on evidence from crystallographical results combined with vibrational spectroscopy and ab-initio molecular orbital calculations. A discussion is given, based mainly on some recent FT-Raman spectroscopic results on the model ionic liquid system of 1-butyl-3-methylimidazolium ([...

Impact of Mixed Feedstocks and Feedstock Densification on Ionic Liquid Pretreatment Efficiency

Energy Technology Data Exchange (ETDEWEB)

Jian Shi; Vicki S. Thompson; Neal A. Yancey; Vitalie Stavila; Blake A. Simmons; Seema Singh

2013-01-01

Background: Lignocellulosic biorefineries must be able to efficiently process the regional feedstocks that are available at cost-competitive prices year round. These feedstocks typically have low energy densities and vary significantly in composition. One potential solution to these issues is blending and/or densifying the feedstocks in order to create a uniform feedstock. Results/discussion: We have mixed four feedstocks - switchgrass, lodgepole pine, corn stover, and eucalyptus - in flour and pellet form and processed them using the ionic liquid 1-ethyl-3-methylimidazolium acetate. Sugar yields from both the mixed flour and pelletized feedstocks reach 90% within 24 hours of saccharification. Conclusions: Mixed feedstocks, in either flour or pellet form, are efficiently processed using this pretreatment process, and demonstrate that this approach has significant potential.

Ionic liquids: an x-ray reflectivity study

International Nuclear Information System (INIS)

Sloutskin, E.; Deutsch, M.; Tamam, L.; Ocko, B.; Kuzmenko, I.; Gog, T.

2005-01-01

Full Text:Ionic liquids are non-volatile, non-flammable and thermally stable solvents, and as such are promising 'green' replacements for traditional volatile organic solvents. In the last years hundreds of Ionic liquids were synthesized. Due to the Ionic liquids great industrial potential, this number is growing at an exceedingly fast rate. Despite the great importance of the interfacial properties of materials for technological applications and basic science, the atomic-scale surface structure of the Ionic liquids has never been studied previously. In our study, synchrotron x-ray reflectivity and surface tensiometry were employed to obtain the surface structure and thermodynamics of two ionic liquids, based on the 1-alkyl-3-methylimidazolium cations. A molecular layer of a density ∼18% higher than that of the bulk is found to form at the free surface of these liquids. The excess concentration of the oppositely charged ions within the surface layer is determined by chemical substitution of the anion. Finally, the observed layering at the surface is contrasted with our measurements on the behavior of classical aqueous salt solutions

Electrochemistry of vanadium(II and the electrodeposition of aluminum-vanadium alloys in the aluminum chloride-1-ethyl-3-methylimidazolium chloride molten salt

Directory of Open Access Journals (Sweden)

Tsuda T.

2003-01-01

Full Text Available The electrochemical behavior of vanadium(II was examined in the 66.7-33.3 mole percent aluminum chloride-1-ethyl-3-methylimidazolium chloride molten salt containing dissolved VCl2 at 353 K. Voltammetry experiments revealed that V(II could be electrochemically oxidized to V(III and V(IV. However at slow scan rates the V(II/V(III electrode reaction is complicated by the rapid precipitation of V(III as VCl3. The reduction of V(II occurs at potentials considerably negative of the Al(III/Al electrode reaction, and Al-V alloys cannot be electrodeposited from this melt. However electrodeposition experiments conducted in VCl2-saturated melt containing the additive, 1-ethyl-3-methylimidazolium tetrafluoroborate, resulted in Al-V alloys. The vanadium content of these alloys increased with increasing cathodic current density or more negative applied potentials. X-ray analysis of Al-V alloys that were electrodeposited on a rotating copper wire substrate indicated that these alloys did not form or contain an intermetallic compound, but were non-equilibrium or metastable solid solutions. The chloride-pitting corrosion properties of these alloys were examined in aqueous NaCl by using potentiodynamic polarization techniques. Alloys containing ~10 a/o vanadium exhibited a pitting potential that was 0.3 V positive of that for pure aluminum.

Influence of the crystalline structure of cellulose on the production of ethanol from lignocellulose biomass

Science.gov (United States)

Smuga-Kogut, Małgorzata; Zgórska, Kazimiera; Szymanowska-Powałowska, Daria

2016-01-01

In recent years, much attention has been devoted to the possibility of using lignocellulosic biomass for energy. Bioethanol is a promising substitute for conventional fossil fuels and can be produced from straw and wood biomass. Therefore, the aim of this paper was to investigate the effect of 1-ethyl-3-methylimidazolium pretreatment on the structure of cellulose and the acquisition of reducing sugars and bioethanol from cellulosic materials. Material used in the study was rye straw and microcrystalline cellulose subjected to ionic liquid 1-ethyl-3-methylimidazolium pretreatment. The morphology of cellulose fibres in rye straw and microcrystalline cellulose was imaged prior to and after ionic liquid pretreatment. Solutions of ionic liquid-treated and untreated cellulosic materials were subjected to enzymatic hydrolysis in order to obtain reducing sugars, which constituted a substrate for alcoholic fermentation. An influence of the ionic liquid on the cellulose structure, accumulation of reducing sugars in the process of hydrolysis of this material, and an increase in ethanol amount after fermentation was observed. The ionic liquid did not affect cellulolytic enzymes negatively and did not inhibit yeast activity. The amount of reducing sugars and ethyl alcohol was higher in samples purified with 1-ethyl-3-methy-limidazolium acetate. A change in the supramolecular structure of cellulose induced by the ionic liquid was also observed.

Anodic oxidation, electro-Fenton and photoelectro-Fenton degradations of pyridinium- and imidazolium-based ionic liquids in waters using a BDD/air-diffusion cell

International Nuclear Information System (INIS)

Garcia-Segura, Sergi; Lima, Álvaro Silva; Cavalcanti, Eliane Bezerra; Brillas, Enric

2016-01-01

Highlights: • Treatment of 1-butyl-4-methylpyridinium chloride and 1-ethyl-3-methylimidazolium chloride. • Almost total mineralization of both compounds by AO-H_2O_2, EF and PEF at high current density. • Release of NH_4"+ and NO_3"− in different proportion depending on the ionic liquid. • Large decay of initial Cl"− with main formation of ClO_3"− and, in lesser extent, of ClO_4"−. • Detection of primary heteroaromatic products and carboxylic acids generated. - Abstract: The degradation of two representative ionic liquids, 1-butyl-4-methylpyridinium chloride and 1-ethyl-3-methylimidazolium chloride, has been studied in 100 cm"3 of aqueous sulfate medium of pH 3.0 by electrochemical advanced oxidation processes (EAOPs) like anodic oxidation with electrogenerated H_2O_2 (AO-H_2O_2), electro-Fenton (EF) and photoelectro-Fenton (PEF). The electrolytic cell contained a boron-doped diamond (BDD) anode and an air diffusion cathode. The main oxidants were hydroxyl radicals formed at the anode surface from water discharge and in the bulk from Fenton’s reaction between generated H_2O_2 and added Fe"2"+. The solutions of both compounds underwent an almost total mineralization with 97% and 94% of dissolved organic abatement by the most powerful PEF at high current density, being similar and slightly lower for AO-H_2O_2 and EF, respectively. At low current density, the pyridinium-based ionic liquid showed similar mineralization rate by AO-H_2O_2 and PEF, whereas the imidazolium-based ionic liquid was more rapidly degraded in the sequence: AO-H_2O_2 < EF < PEF, where the positive effect of UVA irradiation in PEF was more apparent. The current efficiency decreased gradually with increasing current density in all EAOPs and its value was always superior for the latter compound. The NO_3"− and NH_4"+ concentrations produced in each process were quantified by ion chromatography. This technique confirmed a drastic oxidation of Cl"− contained in the parent

Infrared studies of PVC-based electrolytes incorporated with lithium triflate and 1-butyl-3-methyl imidazolium trifluoromethanesulfonate as ionic liquid

Science.gov (United States)

Zulkepeli, Nik A. S. Nik; Winie, Tan; Subban, R. H. Y.

2017-09-01

In this work, 1-butyl-3-methylimidazolium trifluoromethanesulfonate (BMIMCF3SO3) is employed as ionic liquid in PVC-based polymer electrolyte system with lithium triflate (LiCF3SO3) as doping salt. The samples in film form were prepared by quantitatively varying the concentration of BMIMCF3SO3 to a fixed ratio of PVC-LiCF3SO3 using solution cast technique. The highest room temperature ionic conductivity of 1.120 × 10-7 Scm-1 was exhibited by PVC-LiCF3SO3-BMIMCF3SO3 containing 3 wt. % BMIMCF3SO3. FTIR spectra of the polymer electrolytes were examined to study the complexation of the PVC-based polymer electrolytes. Intensity of free ions, ion pairs, and ion aggregates were obtained from FTIR deconvolution in an attempt to correlate with ionic conductivity results. The intensity of free ions was found to be high for sample with 3 wt. % BMIMCF3SO3.

Preparation and characterisation of high-density ionic liquids incorporating halobismuthate anions.

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Cousens, Nico E A; Taylor Kearney, Leah J; Clough, Matthew T; Lovelock, Kevin R J; Palgrave, Robert G; Perkin, Susan

2014-07-28

A range of ionic liquids containing dialkylimidazolium cations and halobismuthate anions ([BiBr(x)Cl(y)I(z)](-) and [Bi2Br(x)Cl(y)I(z)](-)) were synthesised by combining dialkylimidazolium halide ionic liquids with bismuth(III) halide salts. The majority were room temperature liquids, all with very high densities. The neat ionic liquids and their mixtures with 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide were characterised using Densitometry, Viscometry, NMR Spectroscopy, Electrospray Ionisation Mass Spectrometry (ESI), Liquid Secondary Ion Mass Spectrometry (LSIMS), Matrix-assisted Laser Desorption/Ionization Mass Spectrometry (MALDI), X-Ray Photoelectron Spectroscopy (XPS) and Thermogravimetric Analysis (TGA), to establish their speciation and suitability for high-temperature applications.

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

Science.gov (United States)

Quevillon, Michael J; Whitmer, Jonathan K

2018-01-02

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

Ionic liquid pretreatment of poplar wood at room temperature: swelling and incorporation of nanoparticles.

Science.gov (United States)