Journal of Ionic Liquids最新文献

Tremendous efforts are being made toward electrification of the transport sector. Accordingly, next-generation recycling technologies to tackle the large volumes of spent batteries must be urgently innovated. Herein, ionic liquids and the promising ionometallurgy that can overcome some issues of traditional recycling methods are discussed. Ionic liquids-mediated recovery of metals from spent batteries represents a sustainable strategy, featured with new fundamental chemistries. The opportunities for regeneration and reuse of ionic liquids are promising toward a cost-levelized recycling process. The unique chemical environment of ionic liquids also allows the development of coupled electrochemical procedures and upcycling. Future development requires the assessment of continuous operation and holistic process efficiency, technoeconomic and environmental aspects.

The current article deals with the separation of the azeotropic mixture of isopropyl alcohol (IPA) and water using an ionic liquid, 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM][BF₄]) and Deep Eutectic Solvents (DESs), Choline Chloride/glycerol (Glyceline) and Choline Chloride/Ethylene Glycol (Ethaline). Conventional dimethyl sulfoxide (DMSO) solvents are used to compare the results for IPA dehydration. Process modelling and simulation were carried out in the Aspen Plus simulator (v.8.6). The NRTL model was used to calculate the thermodynamic properties as well as the vapour-liquid equilibria of the ternary systems. The process parameters such as entrainer flow rate, binary feed stage, entrainer feed stage, column stages, reflux ratio, reboiler and condenser duties were evaluated using sensitivity analysis and design spec tools of the simulator. The industrial process for both systems, containing a separation column and a recovery column, was simulated at a steady state. Both processes were optimised using the optimisation tool of the simulator and compared based on the energy requirement. Further, based on the simulation results, we proposed an alternate process design for solvent recovery using a flash drum. The results show that more than 99.9 mol% IPA purity can be achieved using both ILs as well as DESs. The overall energy requirement for the separation of IPA-water mixture using [EMIM][BF₄] entrainer in a conventional process was found to be lower than DMSO. The proposed alternate process further reduces the energy requirement compared to the conventional process for both IL and DESs systems.

Aprotic heterocyclic anions (AHAs) can abstract hydrogen atoms from the methylene groups of the trialkylsulfonium and tetraalkylphosphonium cation. The resulting trialkylsulfonium and tetraalkylphosphonium ylides readily capture CO₂ and produce unusual carboxylated zwitterions, in which the distances between the poles, S(P) and O, are 0.274–0.290 nm. The zwitterions are strongly intermolecularly stabilized thanks to the electrostatic attractions between +1.6e(+0.9e) and −0.7e charges. Herein, we report drastic polarity alterations between the states of ionic liquids, ylides, and zwitterions through electronic properties, evolutions of geometries, and interatomic charge transfers. The analysis of the unusual intermolecular attractions was performed in the framework of natural bond orbitals. We propose that a biphasic or triphasic system can be useful to boost the reactions by accounting for the polarities of the intermediates and products. The practical value of the reaction is an enhancement in CO₂ chemisorption.

Pressure-dependent IR spectroscopy is used to investigate the possibility of stabilizing ionic liquid (IL)–hydrophilic bentonite (Bent) composites with the application of high pressures. Ambient-pressure experiments suggest IL hydrophilicity/hydrophobicity impacts cation and anion interactions with Bent. For example, both the cation and anion of hydrophilic 1-butyl-3-methylimidazolium dicyanamide ([BMIM][DCA]) experience composition-dependent vibrational mode wavenumber shifts. However, anion–Bent interactions are suppressed at ambient pressure when the nanoclay is paired with hydrophobic 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([BMIM][NTf₂]). Compression to high pressures triggers significant blue shifts for ring-bound C–H stretching bands. The rates of these changes upon pressurization indicate the two ILs experience different interaction motifs with the Bent surface. Large wavenumber shifts for C₄–H and C₅–H stretching modes of [BMIM][NTf₂] imply preferential coordination to Bent surface sites through these groups. This presumably leaves the C₂–H group available for hydrogen bonding with the NTf₂ anion. The situation is different for [BMIM][DCA], where all three C–H groups on the imidazolium ring appear to interact with Bent surface sites. Depressurization reveals further differences between the two systems. Spectroscopic features are reversible for [BMIM][NTf₂], whereas the C–H stretching mode blue shifts for [BMIM][DCA] are either irreversible or the relaxation is kinetically hindered upon return to ambient pressure. Taken together, the spectroscopic data strongly suggests that IL–Bent interactions are pressure sensitive, and IL assemblages along the interface may be manipulated through the application of high pressure.

Ionic liquids (ILs) are materials with fascinating preorganized and programmable solvent structures and distinctive physicochemical features. ILs have recently been used to create polymeric materials with customized sizes, dimensionalities, morphologies, and functions that are challenging to obtain when using common organic solvents. ILs are individual macromolecules that contain cationic and anionic sites either adjacent to or inside the polymer backbones. The device manufacturing technology using 3D printing can realize the on-demand manufacturing of devices and the design of devices from small to large. Arbitrary devices can also be manufactured by adding various functional substances to ink raw materials—one of the most widely used technologies in additives, energy storage, photoactive, biomedical, sensitive innovative materials, emerging areas, etc. This study provides a literature analysis of recent work on three-dimensional (3D) printing technology over the past few years, emphasizing the distinctive properties of ILs in new 3D printing applications. Finally, we briefly summarize several growth prospects that might result in new developments in this fascinating research area.

Deep eutectic solvents (DESs) are ionic liquid analogues that consist of Lewis or Brønsted acids and bases. These systems are characterized by a substantial decrease in melting points as compared to those of the neat constituents. Activity coefficients at infinite dilution of organic solutes is used as a screening tool for extracting solvents, an approach that is useful for identifying acceptable precursors and assessing separation performance in practical applications. This review assesses the effectiveness of DESs as solvents for chemical separations wherein the data is presented for the activity coefficients at infinite dilution for 33 solutes in different DESs at various temperatures. Additionally, the selectivities and capacities for various solute extraction problems are also appraised from the activity coefficients at infinite dilution at T = 323.15 K; capacity represents the solvent's ability to extract the component.

The intermolecular interactions of amino acids (glycine, L–alanine, and L–valine) in aqueous solutions of an ionic liquid, 1–butyl–3–methylimidazolium methylsulfate [Bmim][MeSO₄] as a function of temperature have been investigated by combination of volumetric and acoustic methods. The density, $\rho$, and speed of sound, $u$, of glycine, L–alanine and L–valine in aqueous 1–buytl–3–methylimidazolium methylsulfate solutions have been measured in the temperature interval T = (288.15, 298.15, and 308.15) K and atmospheric pressure. These data have been used to calculate apparent molar volume $\left(V_{\varnothing }\right)$, and apparent molar adiabatic compressibility $\left(K_{\varnothing ,s}\right)$ of these mixtures at different temperatures. Later, the standard partial molar volume $\left(V_{\varnothing }^0\right)$, standard partial molar volumes of transfer $\left(\Delta V_{\varnothing }^0\right)$, standard partial molar adiabatic compressibility $\left(K_{\varnothing ,s}^0\right)$, and standard partial molar adiabatic compressibility $\left(\Delta K_{\varnothing ,s}^0\right)$ of transfer have been determined for these amino acid solutions from density and speed of sound data. Also, hydration number $\left(n_H\right)$ and various group contribution have been calculated. Finally the results have been interpreted in terms of solute - solvent interactions that exist among the currently investigated systems.

Series of proton conductive membranes were prepared by mixing different weight ratio of 3-hexyl-1-methylimidazolium hydrogensulfite ([C₆C₁Imi][HSO₃]), and N-hexyl-pyridinium hydrogensulfite ([C₆Py][HSO₃]) ionic liquids with poly vinyl alcohol (PVA) polymer. To characterize the PVA-ILs membranes, different methods have been used such as X-ray diffraction (XRD), Fourier-transform infrared (FTIR), and scanning electron microscope (SEM). Moreover, the water uptakes, ion exchange capacity, methanol permeability, and proton conductivity of prepared PVA membranes doped with different weight ratio of ILs have been investigated to find the optimum formulation to use as electrolytes membranes for direct methanol fuel cell. The proton conductivity and the ion exchange capacity were improved as the ILs content increased. At 25 °C, The PVA-60 wt.% of [C₆C₁Imi][HSO₃] membrane had a maximum proton conductivity of 17,47 mS.cm⁻¹, and a methanol permeability of 8.17 10⁻⁷ cm².s ^− 1. Mechanical and thermal data confirmed that addition of ILs improve the membrane flexibility and thermal stability up to 200 °C.

Two types of six Brӧnsted acidic ionic liquids of N-SO₃H tethered cyclic ammonium cations (five, six and seven membered) with four anions namely [AcO]⁻, [HSO₄]⁻, [BF₄]⁻, [PF₆]⁻ were synthesized to evaluate their physical and electrochemical behavior in polar solvents (water, MeOH & CH₃CN) using conductivity and Cyclic Voltammetry techniques. Their comparative Brönsted acidic orders were determined using UV–visible Hammett plots. Except the ionic liquid of [PF₆]⁻ anion with N,N-disulfopiperidinium cation, the thermal stabilities of other ionic liquids found within 230–250 °C. Solvent dependent aggregative nature was observed in polar solvents for the ionic liquids at a particular temperature and concentration. Their aggregative properties were also evidenced by comparison of experimental and computed chemical shift values of additional acidic protons of ¹H NMR spectra. Kamlet-Taft solvatochromic parameters of molecular solvents (E_T^N, α, β) were correlated with their observed conductivities. Piperidinium ionic liquids showed wider electrochemical windows (2.99 V to 2.55 V) in acetonitrile as compared to other cyclic ammonium ionic liquids in polar solvents.

For the industrially relevant hydroformylation of but‑1-ene the concept of supported ionic liquid phase (SILP) has been applied previously. In this work, we have studied the influence of the type of ionic liquid (imidazolium and phosphonium based cations, various anions) on the solubility of the three reagents but‑1-ene, carbon monoxide and hydrogen. For the olefin, the predicted solubility values were determined using the COSMO-RS software tool. These data were compared to the experimentally determined values. A correlation between the predicted solubility and the observed activity within similar ILs could be observed. The highest activity could be obtained with the IL [N₁₈₈₈][NTf₂]. A variation of the olefin chain length supported the observed correlation between solubility and activity. With increasing chain length, the activity of the SILP catalyst also increased. For the undesired consecutive reaction leading to aldols it was found that the substrate solubility does not significantly influence the activity or hydrocarbon accumulation under the used reaction conditions. The anion had a more pronounced effect on the accumulation of aldols, with hydrophilic Cl⁻ and [EtOSO₃]⁻ showing lowest accumulation as well as aldol formation activity, while [NTf₂]⁻ showed highest values for both accumulation and formation activity. It was shown that the Kamlet-Taft-parameter β is a suitable value to be correlated with activity and accumulation for different ILs.