Journal of Ionic Liquids最新文献

The corrosion behavior of carbon steel in MEA-CO₂ media containing [BMIM]BF₄ was investigated in this work. The IL can effectively suppress the corrosion of the steel in the solution and facilitates the activation-passivation transition of the steel in the anodic polarization. Molecular dynamics simulations show that the cationic moiety of the ILs can strong adsorb on the surface of Fe in the parallel mode. However, the high content of the IL results in the slight reduction of the passive potential range of the steel, which may be related to the anions of the IL or the free F⁻ ions. It is demonstrated that the dissociation of BF₄⁻ ions gives rise to a relatively high concentration of F⁻ ions in the solution containing [BMIM]BF₄. The addition of NaF indicates the free F⁻ ions can induce the similar localized corrosion of the steel to that in the case of [BMIM]BF₄.

The binding interactions in complex formation between surface active ionic liquids (SAILs) and polymers (nonionic or anionic) are gaining attention because of their potential applications in novel materials. Therefore, the use of a variety of measurements is required for a better understanding of the interactions involved in polymer/SAIL formation. Here, we have investigated the interactions of nonionic poly(vinylpyrrolidone) (PVP) and anionic sodium carboxymethylcellulose (NaCMC) polymers with SAIL 1-tetradecyl-3-methylimidazolium chloride [C₁₄mim][Cl] in aqueous solution using different measurements such as conductivity, surface tension, fluorescence spectroscopy, dynamic light scattering (DLS) and rheometric measurements. The surface tension, conductivity and fluorescence profiles for SAIL-NaCMC systems provide distinct breakpoints that correspond to four different aggregation states: the concentration at which SAIL monomers begin to attach to the polymer chain (C₁), the critical aggregation concentration C₂ (cac), the saturation concentration (C_S) and the critical micelle concentration (cmc). In the case of SAIL-PVP systems, the surface tension and fluorescence profiles confer three transition states: C₂ (cac), C_S and cmc and only two transition states have been observed in conductivity curves. The cooperative binding of SAIL to the NaCMC/PVP chain at the solution interface was analyzed by calculating various thermodynamic and interfacial parameters. Strong complexation was observed between NaCMC-SAIL molecules compared to PVP-SAIL systems at the air-solution surface. This is due to the non-ionic character of the PVP chain, which shows weak interactions with SAIL in comparison to NaCMC. Furthermore, DLS and fluorescence measurements were used to investigate the interactions between SAIL and polymers.

Ionic liquids (ILs) are liquid salts that exist at or below ambient temperatures and are composed of ion pairs. They offer promising alternatives to toxic, hazardous, highly flammable, and volatile solvents in various applications such as solution preparation, dispersion, gel formation, composites, and polymer melts. ILs possess unique and interesting characteristics, including excellent chemical and thermal stability and low vapor pressures. Understanding the rheological properties of ILs is essential to optimizing IL performance. This paper presents a comparative analysis of the rheological properties of two ionic liquids, NHexylpyridinium tetrafluoroborate (HPyBF4) and NHexylpyridinium bromide (HPyBr), under different shear rates, temperatures, and pressures. Rheological measurements were performed under varying controlled pressure and temperature conditions. The experimental investigation covered a pressure range of 689–12,411 kPa [100–1800 psi] and a temperature range from room temperature up to 522 kelvin (K) [480°F]. The primary objective is to explore and compare the flow behavior and viscoelastic characteristics of HPyBF4 and HPyBr under high-pressure and high-temperature conditions. The experimental data showed that HPyBF4 and HPyBr exhibited shear-thinning behavior, and pressure had an insignificant effect on rheology compared to the temperature effect. Under the same testing conditions, HPyBr showed higher shear stress and viscosity than HPyBF4. This research significantly contributes to the improved understanding of the rheological behavior of these specific ionic liquids and their suitability for diverse industrial and scientific applications, particularly in high-pressure and high-temperature environments.

We have synthesized imidazopyridine-type ionic liquids and evaluated their properties. [C_nimpy][Br] (n = 4, 6, 8, 10), in which an alkyl group was introduced at the N₁ position of imidazo[1,2-a]pyridine, were all solid at room temperature. Exchange of the counteranions of [C_nimpy][Br] with N(CN)₂⁻ and FSI⁻ gave the ionic liquids [C_nimpy][N(CN)₂] and [C_nimpy][FSI] in the liquid state at room temperature. In particular, the DSC thermogram of [C₁₀impy][FSI] showed a clear melting point at 22 °C. In [C_nimpy][TFSI], ionic liquids consisting of cations with short alkyl chain lengths (n = 4,6) were solids at room temperature, while those with long alkyl chain lengths (n = 8,10) were liquids. [C_nimpy][FSI] has lower viscosity than other anion-consisting ionic liquids which showed a liquid state at room temperature. [C_nimpy][FSI] has lower viscosity than other anion-containing ionic liquids. In particular, [C₄impy][FSI], with its relatively short alkyl chain length, exhibited a viscosity of 101 mPa·s at 25 °C, which renders it suitable for practical applications. [C₄impy] [FSI] (50 μM acetonitrile solution) showed fluorescence with maximum absorption at 336 nm. Its fluorescence wavelength was shorter than that of imidazo[1,2-a]pyridine, whereas its fluorescence quantum yield (Φ_F 0.39) was higher. Therefore, it is expected to be used as a composite material by employing FRET with a substance that exhibits fluorescence in the visible region.

This paper aims to investigate the suitability of ionic liquids to be used as a co-solvent along with a few common solvents which are dimethyl sulfoxide (DMSO), acetonitrile, and water as the primary solvent to dissolve polyetheretherketone (PEEK). PEEK is an excellent colourless polymer with top-notch mechanical properties. Currently, there is no solvent capable of dissolving PEEK. Therefore, with ionic liquids (ILs) promising performance as solvents to various material including polymers which has been stated in previous literature, it is assumed that ILs would behave as an excellent solvent for PEEK. In this study, three different ionic liquids were chosen which are tetramethylammonium chloride (TMACL), tetramethylammonium hexafluorophosphate (TMAHFP), and tetramethylammonium sulphate (TMAS). PEEK was exposed to these solvent mixtures at ambient temperature and 50 °C for one hour. Fourier Transform Infrared (FTIR) spectroscopy was used to determine the functional group present in the samples. Results highlighted that PEEK did dissolve in DMSO/TMACL and DMSO/TMAHFP at ambient temperature. As the temperature increased to 50 °C, PEEK dissolution decreased in both mixtures. However, the opposite was observed for DMSO/TMAS. Finally, it was found that water and acetonitrile were not able to dissolve PEEK even with the addition of ILs.

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.

CO₂ capture from industrial processes and power plants, contribute to curbing global warming and advancing sustainability efforts. This study involves the design and synthesis of novel mesoporous silica supported ionic liquid based adsorbents for carbon dioxide capture. Utilization of MSILs delves into the efficiency and mechanisms of CO₂ adsorption, offering insights for sustainable carbon capture technologies in combating greenhouse gas emissions. 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium ethyl sulfate and 1-ethyl-3-methylimidazolium methylsulfate ionic liquids were anchored on the surface of mesoporous silica which then led to highly efficient adsorbent material. Simple, efficient and cost saving methodology was performed to synthesize such highly efficient CO₂ adsorbent materials. In addition, we theoretically predicted the favorable interaction mechanism of chosen molecular entities for CO₂ adsorption using density functional theory (DFT) analysis. Theoretical results depict the strong interaction of molecular entities with CO₂ gas molecules which is clearly evident from the experimental findings.

This work aims to evaluate the anti-corrosion potential of ethyl dimethyl propylammonium bis (trifluoromethyl sulfonyl) imide (EDMPA-TFSI)-ionic liquid on AA3003 alloy in 0.5 M HCl solution in the presence and absence of potassium iodide at ambient and elevated temperatures. The corrosion inhibition of AA3003 alloy by EDMPA-TFSI in the presence of potassium iodide was evaluated using hydrogen evolution measurements at 303 K and 333 K. The results show that in the absence of potassium iodide, EDMPA-TFSI decelerates AA3003 corrosion in an acidic medium with a maximum inhibition efficiency of 93.2 % and 90.5 % obtained at 303 K and 333 K respectively. In the presence of potassium iodide, 94.7 % and 89.8 % inhibition efficiencies were obtained at 303 K and 333 K, respectively. This adsorption behavior is concordant with the Langmuir adsorption isotherm and the corrosion process in the presence of EDMPA-TFSI shows consistency with first-order reaction kinetics. New information on the application of EDMPA-TFSI as a workable corrosion inhibitor is provided herein.

5-Hydroxymethylfurfural (HMF) has emerged as a promising link between biomass and petrochemical products, offering great potential for application and promising market prospects. In this work, we investigated the catalyst for the synthesis of 5-hydroxymethylfurfural (HMF) from glucose using metal chloride or ionic liquid bearing Brönsted and Lewis acid using the continuous flow method. Under optimal conditions, a high HMF yield of 58 % was achieved at 120 °C within 20 min using IL 2/DMSO. For the study on metal chlorides, the reaction yield reached about 43 % HMF within 60 min using AlCl₃ (1 mmol) anhydrous. This research presents a remarkably effective method for synthesizing HMF.

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.