Ionic Liquid Research Articles

Synergistic Dual Activation Catalysis by Saccharin‐Based Ionic Liquids for Diastereoselective Synthesis of Ferrocene‐Appended Furopyranones, Furochromenones, and Benzofuranones

ABSTRACTA practical and straightforward strategy for the synthesis of ferrocene appended furopyranone, furochromenone, and benzofuranone via a metal‐free annulation reaction of imidazolium ylide with enone mediated by saccharin‐based ionic liquid has been reported. The mechanistic studies show an approach through synergistic dual activation of enone and imidazolium ylide via cation and anion of ionic liquid, respectively. This operationally simple protocol offers an easy and rapid access to a library of ferrocene appended furopyranone, furochromenone, and benzofuranone in moderate to good yields through the involvement of a six‐membered transition state.

Advanced High-Voltage Electrolyte Design Using Poly(ethylene Oxide) and High-Concentration Ionic Liquids for All-Solid-State Lithium-Metal Batteries.

Poly(ethylene oxide) (PEO)-based solid polymer electrolytes (SPEs) are among the most promising materials for solid-state lithium metal batteries (LMBs) due to their inherent safety advantages; however, they suffer from insufficient room-temperature ionic conductivity (up to 10-6 S cm-1) and limited oxidation stability (<4 V). In this study, a novel "polymer-in-high-concentrated ionic liquid (IL)" (PiHCIL) electrolyte composed of PEO, N-propyl-N-methylpyrrolidinium bis(fluorosulfonyl) imide (C3mpyrFSI) IL, and LiFSI is designed. The EO/[Li/IL] ratio has been widely varied, and physical and electrochemical properties have been explored. The Li-coordination and solvation structure has been explored through Fourier-transform infrared spectroscopy and solid-state magic-angle spinning nuclear magnetic resonance. The newly designed electrolyte provides a promisingly high oxidative stability of 5.1 V and offers high ambient temperature ionic conductivity of 5.6 × 10-4 S cm-1 at 30 °C. Li|Li symmetric cell cycling shows very stable and reversible cycling of Li metal over 100 cycles and a smooth dendrite-free deposition morphology. All-solid-state cells using a composite lithium iron phosphate cathode exhibit promising cycling with 99.2% capacity retention at a C/5 rate over 100 cycles. Therefore, the novel approach of PiHCIL enables a new pathway to design high-performing SPEs for high-energy-density all-solid-state LMBs.

Design of experiments investigation into the production of all cellulose composites using regenerated cellulosic textiles

All cellulose composites (ACCs) can be produced from native and man-made cellulosic fibres; use of the latter provides an additional application for waste-derived regenerated fibers. ACCs were prepared using an ionic liquid dissolution method, utilizing a regenerated cellulose (Tencel) textile, with and without an interleaf cellulosic film. A design of experiments methodology was applied to explore process-property relationships; concentration of the ionic liquid and the processing time and temperature were investigated. It was found that the film remained in-between the textile layers, rather than penetrating the fiber assembly, in contrast to our previous work on cotton-based ACCs. This is due to the structural differences between Tencel and cotton fabric. A multi-response optimization was conducted through a central composite face centered strategy, which captured the film system more strongly. Optimized processing conditions were identified, yielding a Young’s modulus and strain-to-failure of 5.3 GPa and 3.5% respectively, validated through in-lab samples.

A single-ion transport interfacial layer for solid-state lithium batteries

All-solid-state batteries possess several advantages including high safety, flexibility to use high-capacity metal anodes and are projected to be the next generation energy storage devices. Garnet-type cubic Li7La3Zr2O12 (LLZO) solid electrolyte is of particular interest due to its high ionic conductivity under ambient conditions and compatibility with Li metal. However, large electrode/electrolyte interfacial resistance constraints their development. Herein, the use of a highly lithium ion conducting dilithium phthalocyanine (Li2Pc) in ionic liquid as an interlayer is proposed to effectively suppress the high impedance at the interface thus improving the electrode-electrolyte contact. Fast Li+ mobility and high dielectric constant of dilithium phthalocyanine enhance the kinetics of Li+ transport across the interface. A significant reduction in overpotential and very stable stripping/plating cycling are observed in lithium symmetric cells upon introducing Li2Pc interlayer as compared to the use of bare tantalum doped lithium lanthanum zirconium oxide (LLZTO) electrolyte. Cells comprising interlayer-modified Li|LLZTO|LiFePO4 show high capacity with excellent cycling and rate capability. The performance of full cells using lithiated graphite and lithium titanate anodes has also been evaluated. This study presents a promising application of garnet electrolytes towards the advancement of solid-state lithium batteries.

Synthesis and Application of Antibacterial Poly(ionic liquid)-Based Waterborne Polyurethanes Modified with Siloxane

Synthesis and Application of Antibacterial Poly(ionic liquid)-Based Waterborne Polyurethanes Modified with Siloxane

An Organic Acid-Alkali Coregulated Ionic Liquid Electrolyte Enabling Wide-Temperature-Range Proton Battery.

The broad applications of rechargeable batteries urge people to develop alternative energy storage devices with sustainable resources, high capacity, long cycling life, and wide-temperature operability. Aqueous proton batteries are considered as a state-of-the-art energy storage system due to their intrinsic safety and low cost. However, aqueous electrolytes have a low boiling point and narrow electrochemical stability window, limiting their applications in wide-temperature and high-energy batteries. Herein, a hybrid organic ionic liquid electrolyte with organic alkali 1-methyl-1,2,4-triazole (MTA) protonated by organic acid bis(trifluoromethysulfonyl)imide (HTFSI) as proton carriers and tetramethylene sulfone (TMS) as the solvent, noted as HTFSI-MTA-TMS, exhibited the stable electrochemical windows exceeding 5V at -20°C and 3.5V at 80°C. Benefiting from this electrolyte, the assembled MnO2-S//MoO3 button proton full battery can display an operation voltage up to 1.8V, energy density of 44.8Wh kg-1, and good cycling stability at room temperature when bis(trifluoromethanesulfonyl)imide manganese (II) salt (Mn(TFSI)2) is introduced into the electrolyte, and run well in a wide-temperature range (-20°C-60°C). The work reveals the potential of organic acid-alkali coregulated electrolytes to meet the need of energy storage in a wide-temperature range and will advance the development of high-energy proton batteries.

In-depth exploration of the interface mechanism of aqueous ammonium-ion batteries with ionic liquids

Aqueous ammonium-ion batteries have emerged as a research focus in recent years because of their distinctive advantages. Nevertheless, issues such as the side reaction of water, electrode element dissolution and others have an impact on their stability. The experimental findings demonstrate that the system incorporating ionic liquids (ILs) exhibits gratifying electrochemical performance. The Molecular Dynamics (MD) simulation approach was employed to investigate the alterations of NH4Cl aqueous batteries prior to and subsequent to the addition of imidazolium ionic liquids (ILs), with a focus on the impact on the anode's interface. It is found that the addition of ILs can reduce the interfacial water’s content at low charge. Interestingly, in the case of high charge, the water content at the interface didn’t decrease; instead, it increased. This phenomenon is associated with the initial increase followed by a decrease in the number of ionic liquid (IL) cations. Three conformations for IL cations were found near the interface, which are “parallel”, “slant” and “vertical”, and the proportion of the three had a certain influence on the content of interfacial water. The "parallel" configuration is more effective in reducing the interfacial water content, establishing it as the dominant conformation. The findings reported above will offer new theoretical support for the design and modification of aqueous ammonium ion electrolytes.

Novel vegetable biolubricants containing ionic liquid

Novel biolubricants based on vegetable avocado oils modified by the ionic liquid diethylmethylammonium methanesulfonate (IL), were investigated. Neat (Av) and epoxidized avocado (EAv) oils with 1 wt% IL were studied in a metal-ceramic tribopair under pin-on-disc configuration. The best tribological performance was found for the EAv+ 1 %IL oil, with higher viscosity, and friction coefficient and wear rate up to 74.5 % and 98.8 % lower than that of neat lubricants. The presence of IL and epoxidized oil tribofilm inside the wear tracks was confirmed using X-ray photoelectronic spectroscopy. These results highlight the potential use of ionic liquids as efficient additives in biolubricant oils.

Hollow fibers with encapsulated ionic liquid for gas dehydration

Membrane technology is a viable alternative for achieving energy savings and sustainability, particularly in dehydration applications. The selective removal of water vapor from gas mixtures by membranes enhances the process efficiency furthermore the industry increasingly prioritizes resource conservation and environmental impact, advancements in membrane technology are crucial for meeting these goals and driving progress toward a sustainable future. Our approach consists of the incorporation of a proline amino acid-based ionic liquid encapsulated in carbon capsules, dispersed in a Pebax®1657 matrix, and coated on polyetherimide hollow fibers. The filled capsules have high sorption capacity for both water vapor and carbon dioxide (CO2) contributing for successful exploration for air dehumidification, as well as flue gas, natural gas and biogas dehydration. The membranes had exceptional water vapor permeance, reaching values up to approximately 10,000 GPU while maintaining an H2O/N2 selectivity of around 124,000. CO2/N2 selectivity as high as 100 and promising results for CH4 purification were demonstrated. Long-term studies using alternative modules to prevent saturation of the encapsulated capsules with water vapor and effective regeneration have been proven.

Synthesis of UiO-66-NH2@PILs core-shell composites for CO2 conversion into cyclic carbonates via synergistic catalysis under solvent- and additive-free conditions

Metal-organic frameworks (MOFs) have been hybridized with other functional materials, such as ionic liquids, covalent organic frameworks (COFs), and metallic nanoclusters, to fabricate composite materials. These composites possess the structural characteristics of their individual components and exhibit synergistic properties. In this work, we demonstrate the synthesis of core-shell structure UiO-66-NH2@PILs-x composite materials by encapsulating MOFs within ionic polymers (PILs) with varying thicknesses of PILs shell. These hybrid materials serve as bifunctional catalysts for the conversion of CO2 into cyclic carbonates under solvent- and additive-free conditions through a synergistic catalytic effect facilitating the conversion of CO2 into cyclic carbonates under solvent- and additive-free conditions through synergistic catalytic effect, exhibiting superior catalytic performance and excellent recyclability. This MOFs-based composite material provides a competitive approach for CO2 catalytic conversion.

Functionalization and Applications of Molten Salts and Ionic Liquids

Functionalization and Applications of Molten Salts and Ionic Liquids

Simulating the ionic liquid mixing with organic-solvent clarifies the mixture’s SFG spectral behavior and the specific surface region originating SFG

Molecular dynamics (MD) simulation of the green ionic liquid [C₄mim][PF₆] mixed with polar benzonitrile (BNZ) solvent provides detailed insights into their structural and dynamic properties, essential for electrochemistry and materials science applications. The simulations we carried out at varying mole fractions (XBZN) reveal the mixtures’ physical, structural, and dynamic properties, with radial, spatial, and combined distribution functions, highlighting the effective interaction through H-bonding involved. The simulation indicates that BZN stacks on the cation butyl tail, providing a significant explanation for the unique experimental observations (following). Adding BZN causes the mixture’s liquid dynamics to increase linearly at low XBZN and exponentially at high XBZN, with a notable singular transition at 0.5XBZN. Comprehensive efforts were made to verify and support experimental sum frequency generation (SFG) spectroscopy by simulating the surface structure of the mixtures. Consequently, the simulated BZN stacking structure explains (1) the absence of the C≡N vibrational mode in the SFG spectrum for XBZN < 0.8, and (2) the gradual diminishing of the CH3 SFG signal, which disappears as XBZN approaches 0.5. Finally, this research removes a persistent ambiguity, proving that only the molecular moieties on the surface generate the SFG vibrational signal, while those in the subsurface do not.

Simulation and optimization for flue gas CO2 capture by energy efficient water-lean ionic liquid solvent

Ionic liquids (IL) are treated as advanced materials for energy-saving carbon dioxide (CO2) capture from flue gas but suffer from serious challenges in energy and mass management. Herein, a water-lean IL-based deep eutectic solvent with 1,8-diazabicyclo [5.4.0] undec-7-ene imidazole ([DBU] [IM]) and ethylene glycol (EG) blends was prepared with a screened proportion of IL:EG=7:3. The CO2 loading and saturated solvent viscosity were 1.89 mol/L and 95 mPa·s, respectively. The foundational properties of the IL-EG solvent were determined by experimental measurements and thermodynamic modeling. The vacuum flashing desorption technology was innovatively adopted for energy-saving solvent regeneration. Industrial-scale process simulation of multistage flashing was used to explore the energy consumption during solvent regeneration. Meanwhile, the segmented cooling paved a route for water separation from water-lean solvent. A comprehensive analysis was performed out to optimize the operating parameters for CO2 absorption and desorption. For the recommended 3-stage flashing configuration, the specific process regeneration energy consumption amounted to only 1.54 GJ/tCO2. Consequently, the total capture cost reduced to 48.1 $/tCO2, marking a decrease of 31.28 %, 16.55 % and 10.25 %, compared with MEA solvent, water-lean solvent and biphasic solvent, respectively. This work offered insights for future endeavors in the development of IL-based CO2 capture process from industrial flue gas.

Dispersive solid phase extraction of chloramphenicol and florfenicol in honey sample performed in narrow bore tube with the aid of magnetic ionic liquids prior to HPLC-DAD analysis

The precedence of high levels of antibiotics in animal-derived foods such as honey poses a significant food safety risk. Therefore, the development of an accurate, and reliable method for determining these residues is crucial. In this study, a new extraction method was proposed for the simultaneous determination of chloramphenicol and florfenicol residues in honey samples prior to high performance liquid chromatography analysis. The method involved using amino-functionalized UiO-66 metal–organic framework (NH2-UiO-66) as a sorbent in a narrow bore tube. To begin, the solution was placed into a narrow bore tube and the pH was adjusted to 6. Then, 100 mg of the sorbent was added to the solution. The particles were slowly passed through the solution and collected in the tube bottom. After removing the supernatant phase, 55 µL of 1-butyl-3-methylimidazolium tetrachloroferrate (III) magnetic ionic liquid was used as the elution solvent under sonication for 3 min. The optimized method exhibited low limits of detection (0.19 and 0.44 ng g−1) and quantification (0.63 and 1.4 ng g−1), good extraction recovery (81 and 74 %), and good linearity of the calibration curve (r2 ≥ 0.996) over the ranges of 1.2–500 and 2.4–500 ng g−1 for florfenicol and chloramphenicol, respectively. Precision was satisfactory, with relative standard deviations ≤8.1 % for both intra- and inter-day precisions. The developed method was done on ten honey samples and chloramphenicol was found in five samples.

Fluorescent Ionic Liquid Aggregates: A Self-Assembled Approach for Pesticide Detection and Catalysis.

The unregulated use of pesticides, industrial discharge of heavy metals, waste, and agricultural runoff may contaminate surface water and groundwater, consequently threatening ecosystems and human health. Thus, the sensitive detection and degradation of pesticides are essential for safety. In this context, herein, we have developed benzimidazolium-based fluorescent surfactant assemblies TA-1/SDS and TA-2/SDBS, which exhibit aggregation-induced emission enhancement in an aqueous medium. The aggregates (TA-1/SDS and TA-2/SDBS) displayed a turn-on emission response upon interaction with carbendazim and azamethiphos with limits of detection 7.5 and 7.8 nM, respectively. The FE-SEM and AFM studies revealed that TA-1/SDS and TA-2/SDBS undergo self-assembly with the addition of AZA and CBZ, resulting in the formation of dendritic structures. In addition to the quantification of AZA and CBZ, TA-1/SDS and TA-2/SDBS have also been evaluated to degrade both pesticides and validated using 31P NMR spectroscopy and LC-MS spectrometry.

Efficient synthesis of cellulose acetate through one-step homogeneous acetylation of cotton cellulose in binary ionic liquids

Cellulose acetate (CA) is an important cellulose derivative with a wide range of applications. To adopt a more efficient and environmentally friendly method to synthesize cellulose acetate, a binary ionic liquid mixture of 1-butyl-3-methylimidazole chloride salt (BmimCl) and 1-butyl-3-methyldihydroimidazole phosphate (BmimH2PO4) was used. Compared to the conventional methods, this approach didn't require pre-activation of cellulose and the process of homogeneous acetylation proceeded without a catalyst. By simply adjusting the reaction conditions, cellulose acetate with a degree of substitution (DS) in the range of 0.83–3.0 was produced by one-step homogeneous acetylation without hydrolysis. Furthermore, the cellulose acetate film produced by solvent casting exhibited smooth surface characteristics, 95 % transparency, and 57.9 MPa tensile strength. Therefore, this study highlights the importance of using binary ionic liquid mixtures for facile synthesis of cellulose acetate. Due to their excellent transparency and mechanical properties, newly synthesized cellulose acetate films could replace commercial films.

Binary imidazolium based aqueous ionic liquid droplet on a rough surface: a molecular dynamics study

Ionic liquids (ILs) have garnered immense attention due to their tunable physicochemical properties. In this study, we delve into the wetting behaviour and interfacial properties of aqueous binary IL mixtures containing [EMIM] [BF4] and [HMIM] [BF4] on both smooth and rough graphite surfaces. Employing classical molecular dynamics simulations, we systematically explored the effects of IL concentration and surface morphology on wetting phenomena. To ensure the equilibrium of the systems, we began by calculating the interaction energies between the components. Subsequently, contact angles were computed, shedding light on the wetting characteristics of the aqueous binary IL mixtures. We meticulously examined the density profiles of the IL systems from the substrate to unravel the dominance of one IL over the other, exploiting the hydrophilic nature of [EMIM] [BF4] and the hydrophobic nature of [HMIM] [BF4]. A comprehensive analysis of hydrogen bond distribution allowed us to discern the intricate nature of these aqueous binary IL droplets. We probed the changes in intermolecular forces within the aqueous IL solution by investigating surface tensions. The tunability of these ILs emerges as a significant aspect of our study, paving the way for their tailored application in engineering and scientific domains. Schematic diagram showing the density distribution of hydrophilic and hydrophobic ILs ([EMIM] [BF4] and [HMIM] [BF4]) in water and also the hydrogen bond (HB) distribution of anion ([BF4]−) water inside the droplet on a pillared surface with a surface fraction ( f ) of 0.4 and pillar height of H = 4 .

Synthesis, vibrational, thermal, topological, electronic, electrochemical stability and DFT studies of new DABCO based ionic liquids

The design of new ILs with different anions could provide interesting physico-chemical properties and for these reasons, the knowledge about the synthesis, the thermal, vibrational, topological, electronic, electrochemical properties and interaction between the selected cation-anion in these ILs are important subjects. Therefore, the understanding about these properties of these compounds is an important subject of study. In this work, we studied three ionic liquids based on the 1-decyl-1,4-diazabicyclo[2.2.2]octane, DABCO-cation, where the corresponding anions were [Br]-, [PF6]-, and [N(SO₂CF₃)₂]-. The syntheses of these bicyclic DABCO ionic liquids are based on an alkylation reaction of 1,4-diazabicyclo[2.2.2] octane and 1-bromodecanefollowed by anion exchange. The obtained ILs are characterized by 1H, 13C, 19F and 31P-NMR spectroscopy. Vibrational spectroscopy studies are conducted by infrared (FTIR/ATR) and Raman spectroscopy in the wavenumber range 600–4000 cm-1 and 45–3500 cm-1, respectively. Furthermore, the thermal stabilities were investigated using the thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) methods. Results indicate that the thermal stability follow the order [C10DABCO][Br]<[C10DABCO][PF6]<[C10DABCO][N(SO₂CF₃)₂]. Additionally, the structural parameters, electrostatic potential (ESP) maps, interaction energies, non-covalent interaction (NCI), atoms in molecule (AIM) analysis, natural bond orbital (NBO), frontier molecular orbital (FMO) analysis and Electrochemical window (ECW) are studied and analyzed by means of DFT calculations at the M06–2X-GD3/AUG–cc–pVDZ level of theory.

The Degradation of the 2-Hydroxyethylhydrazinium Nitrate Ionic Liquid System.

The mechanism by which the 2-hydroxyethylhydrazinium nitrate (HEHN) ionic liquid (IL) dissociates via the formation and loss of nitric acid is investigated utilizing the effective fragment potential (EFP) method and various ab initio methods. Additionally, the interactions that dictate the stability of the HEHN IL and contribute to the formation of nitric acid are further assessed using the quasi-atomic orbital (QUAO) bonding analysis. From this work, it is suggested that the formation of nitric acid is dictated by the presence of hydrogen-bonding interactions which appear to become increasingly ionic in nature as the system approaches the bulk, limiting the formation of nitric acid.

The molecular design of novel phospholipid-inspired ionic liquid transdermal penetration enhancers: Innovative insights on the action mode and mechanism

Ionic liquid transdermal penetration enhancers (IL@TPEs) as new enhancement methods have significant advantages in the transdermal drug delivery system. However, the scientific frameworks for the design of efficient IL@TPEs and their applications in transdermal formulations were still lack. So, a series of novel biomimetic phospholipid-inspired IL@TPEs (PIL@TPEs) were designed and synthesized. The developed QSARs proved that enhancement efficacy of PIL@TPEs depended on pKa of drugs and M.W., Polar., and pKa of cations. Surprisingly, the PIL@TPEs dissociated during transdermal process, and skin penetration amounts of acidic drugs was inversely proportional to skin retention amounts of cations, which showed that action modes of PIL@TPEs were different from conventional enhancers. The novel mechanisms of PIL@TPEs were elucidated by quantitative determination of dynamic interaction among cations, anions, drugs, and skins. The PIL@TPEs with high enhancement efficiency owned strong interactions with drugs determined by ATR-FTIR, Raman and NOESY. Moreover, the PIL@TPEs owning better stability in skin ensured the production of strong interactions with lipids and keratins characterized by ATR-FTIR, 1H NMR and CLSM. The good safety of optimized PIL@TPEs was proved by determining cytotoxicity, apoptosis, inflammatory cells, and cytokines. In conclusion, this project will make an important contribution to the design and application of IL@TPEs.