Journal of Ionic Liquids最新文献

In this study a LLX process for the extraction of cobalt by the IL [P₈₈₈₈][Oleate] is analysed in terms of relevant thermodynamic parameters. The process can be considered a typical example of transition metal extraction by an ionic liquid. Conductivity and chemical (FTIR) analyses indicate that Co²⁺ complexes with the IL. Three different models are evaluated, all different with respect to the actual Co²⁺ species that complexes with the IL, as well as the Co²⁺:IL stoichiometry. Based on simulations we identified CoCl₂ as the Co species that enters and complexes with the IL, in a Co²⁺:IL ratio of 1:2. The complexation reaction between the Co-species and the IL is an endothermic, entropy-driven reaction. The influence of the feed composition on Co²⁺ extraction is investigated, including the effect of the nature of the accompanying anion as well as the presence of a salting out cation agent. The higher Co²⁺ extraction from a NO₃⁻ medium is due to the stronger interaction between Co(NO₃)₂ and the IL, reflected by a higher equilibrium constant of Co(NO₃)₂ compared to CoCl₂. Differences in dehydration enthalpy between the ion species involved may contribute as well. Similar effects play a role when comparing uptake rates in solutions containing both Co²⁺ and Na⁺, with Co²⁺ extraction clearly preferred over that of Na⁺. Observed differences in Co²⁺ uptake in the presence of a salting-out agent (NaCl, KCl and NH₄Cl) can be explained in terms of the hydration energy of the salting out cation, the higher this hydration energy, the higher the Co²⁺ uptake by the IL.

The combustion of fossil fuels is an important source of air pollution due to the presence of sulfur-based compounds. In this regard, a reliable atomistic forcefield is required in order to provide insights on solute-solvent interactions, and in designing high aromatic sulfur extracting solvents. In the present work, the excess chemical potentials of thiophene within four 1-butyl-3-methylimidazolium-based ionic liquids were evaluated through the free energy perturbation with replica exchange molecular dynamics methodology by using the CL&Pol polarizable force fields based on Drude oscillators. First, in order to validate the accuracy of the polarizable force fields, a series of thermodynamic properties of pure ionic liquids such as diffusion coefficient, liquid density, dielectric constant, and heat of vaporization were computed using the CL&Pol force field and compared against experimental values. The results from the calculated thiophene excess chemical potential values, indicated that the [C₄mim][CH₃COO] ionic liquid presents the more favorable excess chemical potential (higher solubility) with respect to the thiophene molecule at both 300 K and 343 K in comparison to the other ionic liquids studied. The structural analysis revealed that the ionic liquid anion interacts more closely and with well-defined RDF peaks with the thiophene molecule, the larger anions present higher surrounding particle densities with the thiophene molecules (solvation shell), while the monoatomic anions interact preferentially with the hydrogens close to the sulfur thiophene atom; In contrast no marked solvation layers were observed with the ionic liquid cations.

A new and exciting direction in advanced materials and biomedical engineering is the use of hydrogels based on ionic liquids that are 3D printed. Hydrogels with improved structural integrity and adjustable characteristics are made from ionic liquids, which are renowned for their distinct physicochemical qualities. Utilizing 3D printing technology, which gives precise control over the morphology and spatial arrangement of the finished structures, further expands the potential of these hydrogels. This review discusses the various uses of hydrogels based on ionic liquids that are created on 3D printers, from scaffolds for tissue engineering to drug delivery systems. Ionic liquids and 3D printing together provide a flexible platform for adjusting the hydrogels' mechanical strength, biocompatibility, and responsiveness. The addition of functional components like nanoparticles and bioactive compounds increases the therapeutic potential of these materials. This review covers the latest advancements, obstacles, and potential applications for 3D-printed hydrogels based on ionic liquids. A thorough grasp of how this novel methodology advances materials science and bioengineering and opens the door for next-generation biomedical applications may be gained by delving into the design concepts and fabrication methods.

Hemp fibers are promising biomaterials that have many advantages, such as biodegradability, low production costs, and rapid growth. They can be used as alternatives to other cellulosic fibers that have higher environmental impacts. However, to use hemp fibers effectively, they need to be separated from the lignin in the hemp biomass. This process is called delignification, and it is usually done by using harsh chemicals that are harmful to the environment and human health. In this work, we used a new and green solvent, called deep eutectic solvent-like mixtures, to delignify hemp biomass. Deep eutectic solvent-like mixtures are made from choline chloride and lactic acid, which are cheap, safe, and biodegradable. We tested different combinations of temperature (80–160 °C), time (60–240 min.), and solvent amount (1:10–1:60) to find the best conditions for delignification. We measured the Kappa number, which indicates how much lignin is left in the fibers, and the efficiency of delignification, which indicates how much lignin is removed. The Kappa number of delignified hemp fibers ranged from 10.7 (144 °C, 204 min, 1:30) to 21.8 (160 °C, 150 min, 1:17). The results showed that the optimal conditions to obtain the smallest Kappa number representing 6.6 are the boundary conditions of 160 °C, 240 min, and a ratio of 1:60. This method is more sustainable and environmentally friendly than the conventional methods, and it can help achieve the goal of sustainable development for mankind.

Owing to the extensive research on imidazolium based ionic liquids; the present study aims to design a potentiometric sensor for alkyl methylimidazolium ion. For this, poly(vinyl chloride) PVC membrane based on the neutral ion-pair complexes of cetylpyridinium chloride and sodium dodecyl sulfate (CPy⁺DS⁻) has been developed. The synthesized ion selective electrode (ISEs) have been found to show linear response with near-Nernstian slope for C_nMeImCl (C₁₀MeImCl, C₁₂MeImCl and C₁₄MeImCl). The proposed ISEs show quick response (5–6 s) and provide wide pH range for working. The influence of various ions on the performance of ion-selective electrode is investigated in terms of potentiometric selectivity coefficients, which were determined by separate solution method. The performance of synthesized ISE in examining the critical micellar concentration (cmc) of C_nMeImCl in aqueous, aqua-organic media and in the presence of amino acids (glycine, L-glutamic acid and L-phenylalanine) has been found to be satisfactory and confirmed through conductivity and fluorescence measurements. This emphasizes its worth for in-situ analysis of alkyl methylimidazolium ions, during an organic reaction, and hence possible reaction mechanism evaluation. Different thermodynamic parameters such as Standard Gibbs energies of micellization ($\Delta G_m^{\circ }$), degree of counterion dissociation (α), amphiphile tail transfer Gibbs free energy ($\Delta G_{m,\text{trans}}^{\circ }$) have been evaluated. Further, the analytical application of synthesized electrode as end point indicator in the potentiometric titration of C₁₄MeImCl with SDS has also been explored, which compared well with improved two-phase titration method. The current study is novel as it involves the use of a cheaper material (CPyCl) as ionophore and that the same electrode can be used for different chain alkyl methylimidazolium ions simply by changing the internal reference solutions.

This study explores the tuning of a Pd/Al₂O₃ hydrogenation catalyst for the selective removal of trace acetylene from ethylene-rich feeds by coating the catalyst with non-functionalized and functionalized ionic liquids (denoted as SCILL and Advanced SCILL materials, respectively). These materials were tested in an automated continuous hydrogenation rig converting 3300 ppm of acetylene in excess ethylene, a gas mixture mimicking a technical front-end steam cracker feed composition. While the sulfonic-acid-functionalized IL coating resulted in a highly active but very unselective catalyst converting mainly ethylene to ethane, an Advanced SCILL catalyst prepared from a nitrile-functionalized IL reduced the acetylene concentration down to less than 1 ppm, while leaving over 99% of the ethylene untouched. We also examined the potential transformations of the IL layer under reaction conditions by means of ¹H NMR. Except for a ketone-functionalized IL, which was inherently labile, all tested ILs primarily underwent C2-ethylation or remained unaltered. Our findings highlight the great potential of functionalized ILs in modifying heterogeneous hydrogenation catalysts.

Extraction of sulfur compounds from crude oil is one of the problems of industries related to crude oil. The use of ionic liquids (ILs) as a green solvent to extract these sulfur compounds, especially cyclic sulfur compounds, can be considered a potential point in this regard. A functional theory comparison was made to investigate the interaction between N-butylpyridinium tetrafluoroborate as IL and several different cyclic sulfur compounds including Thiophene, benzothiophene, dibenzothiophene, and 4,6-dibenzothiophene. The difference between the solution phase and the gas phase has been investigated. Based on the results, the proper interaction between the components of IL and the cyclic sulfur compounds, the extraction of these compounds is theoretically possible. Natural bond orbital, atoms in molecules, HOMO-LUMO overlap integral, and electron density difference were analyzed. The analysis informs on the use of ionic liquids as solvents for the removal of sulfur compounds from crude oil. The hydrogen and vander Waals bonds formed between the anion and cation of ionic liquid and the sulfur compounds have been determined. The main bonds are formed between the anion of ionic liquid and the sulfur compounds. Between the compound [C4Py][BF4] and C₄H₄S, the hydrogen bonds are S…H₁₃, F₂₉.... H₃₈, F₂₆…H₃₈, has been established. The hydrogen bonds between the anion of the ionic liquid and the sulfur compound are shorter than the other hydrogen bonds formed. Due to the intermolecular bonds, the transition state with the lowest energy has been obtained. In this way, we will have a proposed mechanism for the extraction of the cyclic compounds from oil with the help of ionic liquids.

Reducing sulfur levels in fuels has gained significant importance in the oil refining sector to curb harmful emissions of sulfur oxides (SO_x), impacting public health and the environment. We conducted liquid-liquid extractions of thiophene from n-paraffin compounds, employing 1-ethyl-3-methylimidazolium dicyanamide [emim][DCA] and 1‑butyl‑3-methylimidazolium dicyanamide [bmim][DCA] ionic liquids at 313.15 K and atmospheric pressure (101.3 kPa). The study involved determining liquid-liquid equilibrium data for three ternary systems: {n-dodecane (1) + thiophene (2) + [bmim][DCA] (3)} and {n-hexadecane (1) + thiophene (2) + [emim][DCA] or [bmim][DCA] (3)}. Furthermore, we computed and compared distribution ratios and selectivity values across these systems to assess their desulfurization competency. The thermodynamic nonrandom two-liquid (NRTL) model was employed to correlate the experimental data. UNISIM steady-state simulator was used to estimate the extraction efficiency of thiophene from n-C₁₆ as a model diesel fuel.

Ionic conductivity plays an important role towards the application of ionic liquids as electrolytes in next-generation batteries and electrochemical processes and is often estimated using the Nernst–Einstein formalism in molecular simulation-based studies. The Nernst–Einstein formalism is useful for dilute systems where ions do not interact with each other, restricting its applicability to dilute solutions. However, this approximation fails in concentrated solutions where ion interactions become significant, which is usually encountered for pure ionic liquids. These ion-ion correlations can dramatically affect ionic conductivity predictions in comparison to that computed under the Nernst–Einstein formalism. This study highlights the challenges associated with calculating ionic conductivity using Einstein formalism and subsequently provides a workflow for such calculations. It has been found that a minimum trajectory length of 60 ns is required to achieve converged results for Einstein ionic conductivity. Guidance is also given to reduce the computational resource requirements for Einstein conductivity determination. This simplification will enable researchers to estimate Einstein conductivity in ionic liquids more efficiently.

Biogas is a renewable energy source and needs to be upgraded to biomethane for injection into the natural gas grid or use as fuel. To design ionic liquid (IL) solvents for biogas upgrading, a computer-aided ionic liquid design (CAILD) method and the corresponding process simulation are presented. The UNIFAC-IL model is employed to calculate the solubility of gases in ILs, while group contribution (GC) based models are used to predict the physicochemical properties of ILs. By using the performance index (PI) as the objective function and the structural feasibility and physicochemical properties as constraints, a mixed-integer nonlinear programming (MINLP) problem is formulated and solved by the generate-and-test method. Two IL solvents, [MMPY][Tf₂N] (1,3-dimethylpyridinium bis(trifluoromethylsulfonyl)imide) and [MMPY][eFAP] (1,3-dimethylpyridinium tris(pentafluoroethyl) trifluorophosphate), are found to be the optimal IL solvents from 880 IL candidates. To perform the process simulation by using the designed ILs, the parameters for the equations of calculation of required properties are regressed. A sensitivity analysis is performed to find the optimal conditions for the process. Finally, the developed process is compared with the water-scrubbing process for biogas upgrading.