Journal of Ionic Liquids最新文献

Betaine-based (BET) deep eutectic solvents (DESs) made with isoalcohols of varying hydrocarbon chain lengths, namely triethylene glycol (TEG), 1, 2-ethanediol (ETD), 1, 3-propanediol (PPD) and 1, 4-butanediol (BTD) were modelled. Their effects on the formation of aqueous biphasic system (ABS) with 2 M dipotassium phosphate salt solution (K₂HPO₄) as well as the extraction of common protein molecules, bovine serum albumin (BSA), were studied using molecular dynamics simulation with Gromacs. Qualitative and quantitative data were used to analyse the simulation results, which includes visualised systems in equilibrium, root mean square deviation (RMSD), root mean square fluctuation (RMSF), radius of gyration, radial distribution function (RDF) and hydrogen bond analysis. The results and literature research validated the role of inorganic salt solute concentration on the phase forming ability as well as the possibility of protein denaturation. More investigations and experimental works are to be carried out regarding the type of inorganic salt and its concentration for aqueous biphasic systems (ABSs) with alcohol based DESs and salt solution for protein extraction purposes. This is essential to understand the salting-out effect and to isolate the effects of hydrocarbon chain length from other influencing factors. Additionally, inorganic salt concentrations, presence of ether linkage as well as hydrocarbon chain length is shown to play a role in the dynamics between molecules in the system as well as protein conformational changes. Overall, ABS incorporating PPD and BTD with hydrocarbon chain lengths not exceeding C4 demonstrated superior performance in terms of protein conformational stability and interaction, showcasing their efficacy in protein extraction process.

This paper explores the effect of adding supercritical carbon dioxide (scCO₂) to Ionic Liquids (ILs) for the microextraction of very diluted pollutants from aqueous matrices. The proposed system uses an IL, trihexyl-tetradecyl-phosphonium bis(trifluoromethylsulfonyl)imide ([P_6,6,6,14][Tf₂N]) and 1-hexyl-3-methyl-imidazolium tris(pentafluoroethyl)trifluorophosphate ([hmim][FAP]), as extractant, and scCO₂ as diluent that may change the solvent capacity by changing the solvent polarity. The study was first carried out for the extraction of 3,3′,4,4′-tetrachlorobiphenyl (PCB-77) from aqueous solutions using a designed microextraction cell. Different ILs, sample volumes and kinetics of extraction were investigated. Results show that within 15 min the maximum extraction percentage was achieved employing a scCO₂ partial pressure of 80 bar. To investigate the influence of the polarity change by the presence of carbon dioxide more broadly, other pollutants with different water solubilities were used. It was observed that scCO₂ (partial pressure) reduced the recoveries for benzophenone and PCB-77 but increased the extraction of triclosan. This is due to the change on solvent's polarity and viscosity of the mixture. This was corroborated through a ternary system simulation including IL-pollutant-scCO₂. All these results establish that the combination of CO₂ and IL can in some cases enhance the extraction, but the affinity between the pollutant and scCO₂ is a key parameter that discerns whether expanding the IL with scCO₂ is beneficial for the extraction.

This study explores the impact of carboxylate ionic liquids (ILs) on the phase transition properties of methylcellulose (MC) in the diluted and semi-diluted regime. Conductivity measurements were used to examine the aggregation of ILs 1-decyl-3-methylimidazolium butanoate ([C₁₀MIM][BUT]), 1-decyl-3-methylimidazolium crotonate ([C₁₀MIM][CRO]), and 1-decyl-3-methylimidazolium pentanoate ([C₁₀MIM][PEN]) in the presence and absence of MC. The interaction between ILs and MC was confirmed using ¹H NMR spectroscopy. The effect of ILs on the phase transition of MC was investigated through UV–vis spectroscopy and oscillatory rheometry. Results indicated that the carboxylate ILs studied tend to interact with MC, reducing polymer-polymer interactions and the apparent viscosity of MC solutions. Furthermore, carboxylate ILs were observed to modulate the sol-gel transition temperature of MC to higher temperatures, while weakening the resulting gel compared to pure MC gels.

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.

Ionic liquids posses efficiency as solvents, co-solvents or agents for applications involving biomolecules. Due to the increasing interest in systems containing proteins and ionic liquids, we hereby present results from molecular dynamics simulations on solutions containing the polypeptide melittin in pure water, in the neat ionic liquid 1-butyl-3-methyl-imidazolium acetate ([BMI][OAc]) and in the equimolar [BMI][OAc]/H₂O mixture. When compared to the solutions containing the ionic liquid, melittin displays higher mobility and flexibility, lower stability and poorer secondary structure preservation in water. The intramolecular hydrogen bonds in melittin do not play a major role in the structural preservation, but intermolecular hydrogen bonds between melittin and the solvent are important. The micro-solvation of melittin demonstrates that anions and water molecules are in closer contact to melittin, whereas the cations maintain larger distances to the polypeptide. The presence of [BMI][OAc] reduces fluctuation in melittin's structure. Only small differences have been found in the structural arrangement of melittin in the neat ionic liquid and the ionic liquid/water mixture.

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.

We first report a novel solvent, base free synthesis of carbonyl compound catalyst by FeCl₃/TEMPO at 40 °C with high-rate. In this article, we examine the mechanism of this catalytic system and compare the reactivity of aromatic alcohols. Furthermore, the efficacy of 3-(2-aminoethyl)-1-methyl-1H-imidazol-3-ium bromide [Aemim]Br could be maintained after seven recycling cycles. High catalyst productivity and reaction rate (5.53 to 22.50) have been accomplished with the use of an enhanced procedure.

This review examines the corrosion inhibition performance of ionic liquids used as corrosion inhibitors for aluminum, copper, magnesium, steel, and their alloys in various aqueous media. The predominant classes of ionic liquids employed are imidazolium, triazolium, thiazolium, phosphonium, pyridinium, ammonium, pyrrolidinium, and pyridinium-based ionic liquids. The pieces of literature revealed that the studies were carried out in acid, base, and salt media and an array of inhibition efficiencies was obtained. Herein, the possible influence of experimental techniques, ionic liquid concentration, ionic liquid structure, and molecular weight on the inhibition efficiency are tabulated and discussed.

Terephthalic acid (H₂TPA) solubility in several ionic liquids (ILs) at multiple concentrations is higher than for any other known solvents at lower temperatures and pressures which suggests low energy purification of H₂TPA from its major impurity, 4-carboxybenzaldehyde (4-CBA) might be possible. To understand the mechanism several strategies were explored to purify H₂TPA by taking advantage of this high solubilizing power of ILs for H₂TPA in the crystallization of unique salts and cocrystals. Using either zwitterionic carboxylate IL-precursors or direct salt formation with carboxylate ILs or amines, a series of salts of mono, dibasic and two ionic cocrystals were obtained including monobasic, [C₁C₁im][HTPA], [N₄₄₄₁][HTPA], [C₄C₁im][HTPA]•0.5H₂TPA (a cocrystal), and [C₁Him][HTPA] ([C₁C₁im]⁺ = 1,3-dimethylimidazolium, [N₄₄₄₁]⁺ = tribuytlmethylammonium, [C₁Him]⁺ = 1-methyl-3-H-imidazolium), dibasic [C₁C₁im]₂[TPA], [C₄C₁im]₂[TPA], [N₄₄₄₄]₂[TPA], [C₁Him]₂[TPA], [H₂N₂₂]₂[TPA], [H₃N₆]₂[TPA], and [HN(CH₂CH₂OH)₃]₂[TPA] ([C₄C₁im]⁺ = 1-butyl-3-methylimidazolium, [N₄₄₄₄]⁺ = tetrabuylammonium, [H₃N₆]⁺ = hexylammonium, [HN(CH₂CH₂OH)₃]⁺ = triethanolammonium, [H₂N₂₂]⁺= diethylammonium), and a second cocrystal [C₂C₁im]Cl•0.5H₂TPA. The formation of these salts suggest a viable method to purify H₂TPA because of preferred salt formation at low energy conditions. One elegant route using 1-ethyl-3-methylimidazolium chloride ([C₂C₁im]Cl) could be especially promising because the cocrystal [C₂C₁im]Cl•0.5H₂TPA was readily isolated and is easily dissociated when exposed to ambient conditions into crystalline H₂TPA and a liquid of hydrated [C₂C₁im]Cl.