On the Performances of Ionic Liquid-Based Electrolytes for Li-NMC Batteries

Herein, the N-butyl-N-methylpyrrolidinium bis(fluorosulfonyl)amide and the N-propyl-N-methylpyrrolidinium bis(fluorosulfonyl)amide room temperature ionic liquids, combined with the lithium bis(trifluoromethanesulfonyl)amide salt, are investigated as electrolytes for Li/LiNi1/3Mn1/3Co1/3O2 (Li/NMC) batteries. To conduct this study, volumetric properties, ionic conductivity and viscosity of the pure ionic liquids and selected electrolytes were firstly determined as a function of temperature and composition in solution. These data were then compared with those measured in the case of the standard alkyl carbonate-based electrolyte: e.g. the EC/PC/3DMC + 1 mol·L−1 LiPF6. The compatibility of the selected electrolytes with the lithium electrode was then investigated by following the evolution of Li/electrolyte interfaces through impedance measurements. Interestingly, the impedances of the investigated Li/electrolyte interfaces were found to be more than three times lower than that measured using the standard electrolyte. Finally, electrochemical performances of the ionic liquid-based electrolytes were investigated using galvanostatic charge and discharge and cyclic voltammetry of each Li/NMC cell. Using these electrolytes, each tested Li cell reaches up to 145 mA·h·g−1 at C/10 and 110 mA·h·g−1 at C with a coulombic efficiency close to 100 %.

Thermodynamic Properties of Dichloromethane, Bromochloromethane, and Dibromomethane under Elevated Pressure: Experimental Results and SAFT-VR Mie Predictions

The speeds of sound in dibromomethane, bromochloromethane, and dichloromethane have been measured in the temperature range from 293.15 to 313.15 K and at pressures up to 100 MPa. Densities and isobaric heat capacities at atmospheric pressure have been also determined. Experimental results were used to calculate the densities and isobaric heat capacities as the function of temperature and pressure by means of a numerical integration technique. Moreover, experimental data at atmospheric pressure were then used to determine the SAFT-VR Mie molecular parameters for these liquids. The accuracy of the model has been then evaluated using a comparison of derived experimental high-pressure data with those predicted using SAFT. It was found that the model provide the possibility to predict also the isobaric heat capacity of all selected haloalkanes within an error up to 6%.

Enhancing Liquid-Phase Olefin-Paraffin Separations Using Novel Silver-Based Ionic Liquids

This paper describes the extraction of C5-C8 linear α-olefins from olefin/paraffin mixtures of the same carbon number using silver(I)/N,N-dimethylbenzamide bis(trifluoromethylsulfonyl)imide ([Ag(DMBA)₂][Tf₂N]) or silver(I)/propylamine bis(trifluoromethylsulfonyl)imide ([Ag(PrNH₂)₂][Tf₂N]) as the extracting agent. The separation performance of the system increased with increasing chain length. [Ag(DMBA)₂][Tf₂N] appeared to outperform [Ag(PrNH₂)₂][Tf₂N] in terms of both selectivity and distribution coefficient. The [Ag(DMBA)₂][Tf₂N] system was successfully modeled using the universal quasi-chemical activity coefficient (UNIQUAC) model. These results support the potential future development of amine/amide-based ligands for producing soluble silver complexes useful for the separation of olefins from paraffins.

Chaotropicity: a key factor in product tolerance of biofuel-producing microorganisms

Fermentation products can chaotropically disorder macromolecular systems and induce oxidative stress, thus inhibiting biofuel production. Recently, the chaotropic activities of ethanol, butanol and vanillin have been quantified (5.93, 37.4, 174kJkg(-1)m(-1) respectively). Use of low temperatures and/or stabilizing (kosmotropic) substances, and other approaches, can reduce, neutralize or circumvent product-chaotropicity. However, there may be limits to the alcohol concentrations that cells can tolerate; e.g. for ethanol tolerance in the most robust Saccharomyces cerevisiae strains, these are close to both the solubility limit (<25%, w/v ethanol) and the water-activity limit of the most xerotolerant strains (0.880). Nevertheless, knowledge-based strategies to mitigate or neutralize chaotropicity could lead to major improvements in rates of product formation and yields, and also therefore in the economics of biofuel production.

Acoustic and Volumetric Properties of Diluted Solutions of Water in Ionic Liquids

Herein, we report the densities and speeds of sound in binary mixtures of three hydrophobic and one hydrophilic ionic liquids: 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide, [C4mim][NTf2], 1-butyl-1-methylpyrrolidinium bis[(trifluoromethyl)sulfonyl]imide, [C4mpyr][NTf2], 1-propyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide, [C3mim][NTf2] and 1-ethyl-3-methylimidazolium thiocyanate, [C2mim][SCN], with water at 298.15 K and 0.1 MPa. The concentration range of water, which encompassed relatively small values well below the saturation point, is often regarded as an impurity for hydrophobic ionic liquids. On the basis of experimental results the molar volume, adiabatic molar compressibility, partial molar volume and apparent molar volume, as well as, partial molar and apparent molar isentropic compressibility properties were then calculated. Interesting results are obtained using the solutions based on the hydrophilic [C2mim][SCN], since these mixtures are characterized by relatively low density and high values of speed of sound. Furthermore, the partial molar volumes and partial molar adiabatic compressibilities of water in solution with [C2mim][SCN] are the lowest among the investigated in mixtures with ionic liquids. However, in the case of the hydrophobic ionic liquid solutions, only small differences are observed for molar adiabatic compressibilities with the change of the cation structure, i.e. for water + [C4mim][NTf2] or + [C4mpyr][NTf2]. A more pronounced difference has been observed for the partial molar compressibility of water in solutions with these two ionic liquids.

Thermal Properties of Alkyl-triethylammonium bis{(trifluoromethyl)sulfonyl}imide Ionic Liquids

In this work, we address the thermal properties of selected members of a
homologous series of alkyltriethylammonium bisf(trifluoromethyl)sulfonylgimide ionic
liquids. Their phase and glass transition behavior, as well as their standard isobaric heat
capacities at 298.15 K, were studied using differential scanning calorimetry (DSC),
whereas their decomposition temperature was determined by thermal gravimetry analysis.
DSC was further used to measure standard molar heat capacities of the studied ionic liquids
and standard molar heat capacity as a function of temperature for hexyltriethylammonium,
octyltriethylammonium, and dodecyltriethylammonium bisf(trifluoromethyl)sulfonylgimide
ionic liquids. Based on the data obtained, we discuss the influence of the alkyl chain
length of the cation on the studied ionic liquids on the measured properties. Using viscosity
data obtained in a previous work, the liquid fragility of the ionic liquids is then discussed.
Viscosity data were correlated by the VTF equation using a robust regression along a
gnostic influence function. In this way, more reliable VTF model parameters were obtained than in our previous work and a good estimate of the liquid fragility of the ionic liquids was made.

Social Services of General Interest: The EU Competence Regime and a Constitution of Social Governance

In discussing the potential role of the EU, the Member States, their composite parts and civil society organisations in establishing social services of general interest at sub-national, national, transnational and EU wide levels, this chapter explores the EU competence regime for social services of general interest. Its analysis contradicts a tendency in academic writing to demand protection of national prerogatives for shaping welfare states against EU intervention at all costs, because this would be counterproductive for the progress of the EU project. It submits that an EU constitution of social governance should create mixed responsibilities so that the EU, states and civil society actors support each other in creating preconditions for social integration in the EU. It uses the field of social services of general interests as an example of applying this general theoretical concept.

Solid–liquid equilibria in systems [Cxmim][Tf2N] with diethylamine

In the present work, the solid–liquid–liquid equilibrium in the binary system of diethylamine (1) and ionic liquid (2) 1-methyl-3-ethylimidazolium bis(trifluoromethylsulfonyl)imide and solid–liquid equilibrium in system 1-methyl-3-butylimidazolium bis(trifluoromethylsulfonyl)imide was studied. Phase equilibrium was determined experimentally by means of a polythermic method. These data were then used to determine the activity coefficients for both ionic liquids. For the pure diethylamine the enthalpy of fusion was determined by differential scanning calorimetry, because to the best of our knowledge, this data is not yet reported in the open literature, a contrario of pure ionic liquids tested during this work.

CO2 capture and electrochemical conversion using superbasic [P66614][124Triz]

The ionic liquid trihexyltetradecylphosphonium 1,2,4-triazolide, [P66614][124Triz], has been shown to chemisorb CO2 through equimolar binding of the carbon dioxide with the 1,2,4-triazolide anion. This leads to a possible new, low energy pathway for the electrochemical reduction of carbon dioxide to formate and syngas at low overpotentials, utilizing this reactive ionic liquid media. Herein, an electrochemical investigation of water and carbon dioxide addition to the [P66614][124Triz] on gold and platinum working electrodes is reported. Electrolysis measurements have been performed using CO2 saturated [P66614][124Triz] based solutions at −0.9 V and −1.9 V on gold and platinum electrodes. The effects of the electrode material on the formation of formate and syngas using these solutions are presented and discussed.

A comparative study on the thermophysical properties for two bis[(trifluoromethyl)sulfonyl]imide-based ionic liquids containing the trimethyl-sulfonium or the trimethyl-ammonium cation in molecular solvents

Herein, we present a comparative study of the thermophysical properties of two homologous ionic liquids, namely, trimethyl-sulfonium bis[(trifluoromethyl) sulfonyl]imide, [S₁₁₁][TFSI], and trimethyl-ammonium bis[(trifluoromethyl)sulfonyl]imide, [HN₁₁₁][TFSI], and their mixtures with propylene carbonate, acetonitrile, or gamma butyrolactone as a function of temperature and composition. The influence of solvent addition on the viscosity, conductivity, and thermal properties of IL solutions was studied as a function of the solvent mole fraction from the maximum solubility of IL, x_s, in each solvent to the pure solvent. In this case, x_s is the composition corresponding to the maximum salt solubility in each liquid solvent at a given temperature from 258.15 to 353.15 K. The effect of temperature on the transport properties of each binary mixture was then investigated by fitting the experimental data using Arrhenius' law and the Vogel-Tamman-Fulcher (VTF) equation. The experimental data shows that the residual conductivity at low temperature, e.g., 263.15 K, of each binary mixture is exceptionally high. For example, conductivity values up to 35 and 42 mS·cm^-1 were observed in the case of the [S ₁₁₁][TFSI] + ACN and [HN₁₁₁][TFSI] + ACN binary mixtures, respectively. Subsequently, a theoretical approach based on the conductivity and on the viscosity of electrolytes was formulated by treating the migration of ions as a dynamical process governed by ion-ion and solvent-ion interactions. Within this model, viscosity data sets were first analyzed using the Jones-Dole equation. Using this theoretical approach, excellent agreement was obtained between the experimental and calculated conductivities for the binary mixtures investigated at 298.15 K as a function of the composition up to the maximum solubility of the IL. Finally, the thermal characterization of the IL solutions, using DSC measurements, showed a number of features corresponding to different solid-solid phase transitions, T_S-S, with extremely low melting entropies, indicating a strong organizational structure by easy rotation of methyl group. These ILs can be classified as plastic crystal materials and are promising as ambient-temperature solid electrolytes. © 2013 American Chemical Society.

Selective hydrogenation of fatty acids to alcohols over highly dispersed ReOx/TiO2 catalyst

Production of fatty alcohols through selective hydrogenation of fatty acids was studied over a 4% ReOx/TiO2 catalyst. Stearic acid was hydrogenated to octadecanol at temperatures and pressures between 180-200 degrees C and 2-4 MPa, with selectivity reaching 93%. A high yield of octadecanol was attributed to a strong adsorption of the acid compared to alcohol on the catalyst, which inhibits further alcohol transformation to alkanes. Low amounts (<7%) of alkanes (mainly octadecane) were formed during the conversion of stearic acid. However, it was found that the catalyst could be tuned for the production of alkanes. The reaction intermediates were octadecanal and stearyl stearate. Based on the reaction products analysis and catalyst characterization, a reaction mechanism and possible pathways were proposed.

Can the scaling behavior of electric conductivity be used to probe the self-organizational changes in solution with respect to the ionic liquid structure? The case of [C8MIM][NTf2]

Electrical conductivity of the supercooled ionic liquid [C8MIM][NTf2], determined as a function of temperature and pressure, highlights strong differences in its ionic transport behavior between low and high temperature regions. To date, the crossover effect which is very well known for low molecular van der Waals liquids has been rarely described for classical ionic liquids. This finding highlights that the thermal fluctuations could be dominant mechanisms driving the dramatic slowing down of ion motions near Tg. An alternative way to analyze separately low and high temperature dc-conductivity data using a density scaling approach was then proposed. Based on which a common value of the scaling exponent [gamma] = 2.4 was obtained, indicating that the applied density scaling is insensitive to the crossover effect. By comparing the scaling exponent [gamma] reported herein along with literature data for other ionic liquids, it appears that [gamma] decreases by increasing the alkyl chain length on the 1-alkyl-3-methylimidazolium-based ionic liquids. This observation may be related to changes in the interaction between ions in solution driven by an increase in the van der Waals type interaction by increasing the alkyl chain length on the cation. This effect may be related to changes in the ionic liquid nanostructural organization with the alkyl chain length on the cation as previously reported in the literature based on molecular dynamic simulations. In other words, the calculated scaling exponent [gamma] may be then used as a key parameter to probe the interaction and/or self-organizational changes in solution with respect to the ionic liquid structure.

High-pressure phase equilibrium in the {carbon dioxide (1) + 1-chloropropane (2)} binary system

Abstract The current study reports original vapour-liquid equilibrium (VLE) for the system {CO2 (1) + 1-chloropropane (2)}. The measurements have been performed over the entire pressure-composition range for the (303.15, 313.15 and 328.15) K isotherms. The values obtained have been used for comparison of four predictive approaches, namely the equation of state (EoS) of Peng and Robinson (PR), the Soave modification of Benedict–Webb–Rubin (SBWR) EoS, the Critical Point-based Revised Perturbed-Chain Association Fluid Theory (CP-PC-SAFT) EoS, and the Conductor-like Screening Model for Real Solvents (COSMO-RS). It has been demonstrated that the three EoS under consideration yield similar and qualitatively accurate predictions of VLE, which is not the case for the COSMO-RS model examined. Although CP-PC-SAFT EoS exhibits only minor superiority in comparison with PR and SBWR EoS in predicting VLE in the system under consideration, its relative complexity can be justified when taking into account the entire thermodynamic phase space and, in particular, considering the liquid densities and sound velocities over a wider pressure-volume-temperature range.

Olefin / Paraffin separation using Task-Specific Materials based on Ionic Liquids: Advances in Gas Processing

In this work, 1-hexene was extracted from its mixtures with n-hexane in varying ratios using a task specific ionic liquid. Herein, the ionic liquid (IL) 1-butyl-3-methylimidazolium nitrate, [BMIM][NO3], was used and examined with and without the addition of a metal salt. The impact of water on both selectivity and distribution coefficient was also tested. Four potential metal salts were investigated, the results of which demonstrate that the dissolution of transition-metal salts in the IL improves the separation of 1-hexene from n-hexane through metal-olefin complexation. Additionally, the presence of water in IL solutions containing metal salt enhances this selectivity. Finally, UNIFAC was used to correlate the experimental LLE data with good accuracy.