Ionic liquids synthesis and applications: An overview

Anisotropic conductive eutectogels for strain sensing and triboelectric nanogeneration in extreme environments

Conductive hydrogels have attracted widespread attention for their promising application prospects in portable and flexible electronic devices. However, hydrogels commonly suffer from problems such as solvent volatilization and freezing at low temperatures. Inspired by tissues such as human muscles, tendons, and ligaments, this study proposes a facile method to produce anisotropic conductive strong and tough eutectogels through directional freezing integrated with solvent substitution (DFSS) strategy. Eutectogels with anisotropic characteristics exhibit a highly anisotropic structure, conferring distinctive anisotropic mechanical properties and electrical conductivity. The prepared anisotropic PVA-M-DES eutectogels exhibit excellent mechanical properties (high strength of 6.31 MPa, high toughness of 20.75 MJ m-3, elastic modulus of 2.36 MPa, and fracture strain of 596%), high conductivity (0.17 S m-1), excellent anti-freezing and anti-drying properties. Environment-tolerant anisotropic PVA-M-DES eutectogels can be assembled into strain sensor and triboelectric nanogenerator to achieve real-time monitoring of various human motions and have potential applications in wearable electronics, personal healthcare, energy harvesting, and human-machine interfaces.

PNIPAAm-based temperature responsive ionic conductive hydrogels for flexible strain and temperature sensing

Conductive hydrogels have received much attention in the field of flexible wearable sensors due to their outstanding flexibility, conductivity, sensitivity and excellent compatibility. However, most conductive hydrogels mainly focus on strain sensors to detect human motion and lack other features such as temperature response. Herein, we prepared a strain and temperature dual responsive ionic conductive hydrogel (PPPNV) with an interpenetrating network structure by introducing a covalent crosslinked network of N-isopropylacrylamide (NIPAAm) and 1-vinyl-3-butylimidazolium bromide (VBIMBr) into the skeleton of the hydrogel composed of polyvinylalcohol (PVA) and polyvinylpyrrolidone (PVP). The PPPNV hydrogel exhibited excellent anti-freezing properties (-37.34 °C) and water retention with high stretchability (∼930 %) and excellent adhesion. As a wearable strain sensor, the PPPNV hydrogel has good responsiveness and stability to a wide range of deformations and exhibits high strain sensitivity (GF=2.6) as well as fast response time. It can detect large and subtle body movements with good signal stability. As wearable temperature sensors, PPPNV hydrogels can detect human physiological signals and respond to temperature changes, and the volumetric phase transition temperature (VPTT) can be easily controlled by adjusting the molar ratio of NIPAAm to VBIMBr. In addition, a bilayer temperature-sensitive hydrogel was prepared with the temperature responsive hydrogel by two-step synthesis, which shows great promising applications in temperature actuators.

Synthesis and applications of ionic liquids for chromatographic analysis

Ionic liquids (ILs) have emerged as more desirable liquids than conventional solvents for chemistry, material science, engineering and environmental science. The scientific literature reveals an exponential increase in the number of research projects aimed at exploring the chromatographic features of ionic liquids. The review provides sound scientific data to examine the structural characteristics of ionic liquids that make them ideal for use in chromatography. This contribution is distinctive since it integrates the synthesis, benefits, drawbacks, and possible uses of ionic liquids in several chromatographic separation processes. Keeping the cation the same, the introduction of different anions is also possible, and this strategy leads to the synthesis of a series of different ionic liquids with varying properties. A detailed probe is given on the influence of ionic liquid structure and properties on their chromatographic behavior, both as stationary phase and mobile phase and/or mobile phase additives. Ionic liquid based immobilized stationary phases and their analyte retention mechanisms (hydrogen bonding, electrostatic forces of attraction, π-π stacking, ion exchange, and hydrophilic interactions, etc.) are critically discussed. Finally, a thorough analysis of the literature suggests that IL-based stationary phases may undergo multi-mode and more flexible retention mechanisms. Their dual polarity can facilitate interaction with both polar and non-polar compounds. Similarly, using IL as a mobile phase can offer more pragmatic and sustainable options for enantiomer separation.

A novel recyclable hydrolyzed nanomagnetic copolymer catalyst for green, and one-pot synthesis of tetrahydrobenzo[b]pyrans

Polymer-based catalysts have garnered significant interest for their efficiency, reusability, and compatibility with various synthesis processes. In catalytic applications, polymers offer the advantage of structural versatility, enabling functional groups to be tailored for specific catalytic activities. In this study, we developed a novel magnetic copolymer of methyl methacrylate and maleic anhydride (PMMAn), synthesized via in situ chemical polymerization of methyl methacrylate onto maleic anhydride, using benzoyl peroxide as a free-radical initiator. This polymerization process results in a robust copolymer matrix, which was subsequently hydrolyzed in an alkaline aqueous solution to introduce additional functional groups, yielding hydrolyzed PMMAn. These functional groups enhance the copolymer's ability to support the deposition of magnetic nanoparticles and participate in catalytic reactions. Following hydrolysis, we fabricated a unique magnetic composite, Fe3O4@Hydrol-PMMAn, by in situ coprecipitating Fe3O4 nanoparticles onto the hydrolyzed copolymer, creating a stable nanocatalyst. The structural and magnetic properties of Fe3O4@Hydrol-PMMAn were thoroughly analyzed using FTIR, XRD, SEM, EDX, VSM, and TGA. The Fe3O4@Hydrol-PMMAn nanocatalyst demonstrated remarkable catalytic performance in synthesizing tetrahydrobenzo[b]pyran derivatives through a three-component reaction, conducted without solvents to support green chemistry principles. A series of reaction parameters were optimized, including solvent choice, catalyst loading, and recyclability. The catalyst performed efficiently across a broad range of aldehydes, delivering high product yields (81-96%) with rapid reaction times (5-30 min) at a low catalyst loading of 0.015 g. A hot filtration test confirmed the heterogeneous nature of the nanocatalyst, which could be recycled up to four cycles with minimal loss in activity. The high yield, short reaction time, solvent-free conditions, and excellent reusability make Fe3O4@Hydrol-PMMAn a promising catalyst. These findings underscore its potential for converting waste products into valuable compounds, highlighting its utility in organic transformations and sustainable synthesis practices. Collectively, this work demonstrates that Fe3O4@Hydrol-PMMAn is highly effective for organic compound synthesis, advancing the development of versatile, sustainable nanocatalysts.

Enhanced extraction of methylene blue by dodecyl-methyl imidazolium dodecyl sulfate GUMBOS - magnetic alginate beads

In this study, dodecyl-methyl imidazolium dodecyl sulfonate ([C12MIm][DS]) GUMBOS were synthesized and incorporated into alginate with γ-Fe2O3 to fabricate magnetic adsorbent beads ([C₁₂MIm][DS]-beads) for methylene blue (MB) removal. Characterization via ESI-MS, FT-IR, SEM, BET, and TGA confirmed their structure and properties. The beads achieved a maximum adsorption capacity of 4.5 mg/g at pH 10 with an initial MB concentration of 500 mg/L, following pseudo-first-order kinetics and the Langmuir isotherm model. Thermodynamic studies confirmed the process was exothermic. Even after six recycling cycles, the beads retained similar morphology and an MB removal percentage of 57.6%. The beads demonstrated high adsorption efficiency (70%) in the presence of Cu2⁺, ibuprofen, and malachite green, comparable to MB removal alone. These results highlight the potential of [C12MIm][DS]-beads as effective adsorbents for water remediation applications.

Highly Efficient and Reversible Carbon Dioxide Capture by Carbanion-Functionalized Ionic Liquids

Due to the active unstable nature of carbon anions, it is challenging to develop carbanion-functionalized ionic liquids (ILs) for efficient and reversible carbon dioxide (CO2) capture. Here, a series of carbanion-based ILs with large conjugated structures were designed and a promising system was achieved through tuning the nucleophilicity of carbanions and screening the cation. The ideal carbanion-functionalized IL trihexyl(tetradecyl)phosphonium N,N-diethycyanoacetoamide ([P66614][DECA]) showed equimolar chemisorption of CO2 ( up to 0.98 mol CO2/mol IL) under ambient pressure and excellent absorption rate. What's more, the combined CO2 can be released easily, leading to excellent reversibility due to high stability of anion conjugated structures. More importantly, the presence of water had negligible effect on the absorption capacity, which makes it potential to be applied to the CO2 capture in industrial flue gas. The chemisorption mechanism of the carbanion and CO2 was confirmed by spectroscopic investigations and DFT calculations, where carboxylic acid product was formed through proton transfer after the carbanions reacted with CO2. Considering that high capacity, quick rate as well as excellent reversibility, these carbanion-functionalized ILs should certainly represent competitive candidates for further scale up and practical application in CO2 capture.

Adsorption Removal of NO2 Under Low-Temperature and Low-Concentration Conditions: A Review of Adsorbents and Adsorption Mechanisms

The efficient mitigation of harmful nitrogen oxides (NOx) under ambient conditions remains a challenging task. Selective adsorption offers a viable solution for the capture of low-concentration NOx from the polluted stream at low temperatures. This review summarizes recent progress in the development of NO2 adsorbents, delves into the understanding of adsorption mechanisms, and discusses the criteria for evaluating their performance. First, the present NO2 adsorbents are categorized according to their distinct characteristics. This review then provides insights into the mechanisms of adsorption, highlighting the interaction between active sites and NO2, drawing from both experimental and theoretical research. The performance of these adsorbents is also assessed, focusing on their capacity, reusability, stability and selectivity. Finally, perspectives are proposed to address the significant challenges and explore potential advancements for NO2 adsorbents, aiming to enhance their suitability for diverse practical application scenarios.

Interaction between newly synthesized surface-active ionic liquids with pharmaceutically active anion and bovine serum albumin

This work describes the synthesis and properties of new surface active (octyl-, and dodecyl-) imidazolium and choline-based ionic liquids with pharmaceutically active 5-fluorouracil anion (SAAPI-IL). The effect of the novel SAAPI-IL on the secondary and tertiary structure of bovine serum albumin (BSA) was studied using circular dichroism (CD) spectroscopy. The binding constants of BSA with SAAPI-IL were estimated from the fluorescence quenching of BSA. The influence of the length of the alkyl chain SAAPI-IL on the binding constant with BSA was analyzed. The localization of ions on BSA was estimated using the molecular docking method. Also, the effect of alkyl substituent length on the aggregation tendency of SAAPI-IL was studied by dynamic light scattering (DLS). Cytotoxicity and selectivity of SAAPI-ILs on cancer and normal cell lines were compared to molecular 5-fluorouracil and API-IL without the alkyl substituents. Surprisingly, increasing the length of the alkyl substituent did not increase the binding of SAAPI-IL to BSA. On the other hand, [C8Ch][FU] showed selectivity against A 549 cell line, which 5-fluorouracil does not possess.

Clay minerals and clay-based materials for heavy metals pollution control

Heavy metal contamination is a huge hazard to the environment and human health, and research into removing heavy metals from their primary sources (industrial and agricultural wastes) has increased significantly. Adsorption has received interest due to its distinct benefits over other treatment approaches. The distinctive qualities of clay minerals, such as their high specific surface area, strong cation exchange capacity, and varied structures, make them particularly ideal for use in the manufacture of adsorbents. The customizable structure and performance of clay minerals allow for unprecedented diversity in adsorbent creation, opening up new possibilities for the development of high-efficiency and functional adsorption technologies. In this review, various approaches for developing optimal adsorbents from raw materials are presented. Then, the correlation between functionalization and performance is investigated, focusing on the effects of structural features and surface properties on adsorption performance. The research progress on the synthesis of adsorbents using clay minerals and other functional materials is systematically reported. Finally, the challenges and opportunities in designing and utilizing innovative clay mineral adsorbents are discussed.

Utilizing ionic liquids as eco-friendly and sustainable carriers for delivering nucleic acids: A review on the revolutionary advancement in nano delivery systems

Ionic liquids (ILs) are an extremely versatile class of chemicals. It has been shown that they can effectively pass through many biological barriers in the human body to deliver medications. ILs are solvents noted for their ecological friendliness; they contain equal amounts of cations and anions and remain liquid at temperatures below 100 °C. Hence, these are ideal for biomedical applications owing to their advantageous properties such as biocompatibility, solubility, and adaptability. ILs are widely reported to improve the solubility and stability of nucleic acids (DNA and RNA) in aqueous conditions, allowing for more effective delivery. Certain ILs have shown the ability to enhance the absorption of nucleic acids into cells. In addition, ILs can also be used to create vectors for gene delivery, such as liposomes and nanoparticles, thereby improving the transfection efficiency of plasmid DNA and siRNA. Subsequently, the application of ILs for nucleic acid delivery has increased significantly in recent years. In this context, we believe that using ILs to enhance the transport of nucleic acids will have a considerable effect as a novel and crucial therapeutic method in the upcoming decades. The use of ILs as solvents to preserve the natural structure of DNA and RNA shows promise for a variety of biotechnological and medical applications. Notably, ILs may be utilized for a variety of functions, including extracting, concentrating, stabilizing, and spreading nucleic acids inside cells. Our review emphasizes the key findings of research works published in this domain, wherein outstanding effectiveness of delivering RNA to the desired areas was achieved, and was made possible through the utilization of ILs.

Computer-Assisted Strategies as a Tool for Designing Green Monomer-Based Molecularly Imprinted Materials

Molecularly imprinted polymers (MIPs) are defined as artificial receptors due to their selectivity and specificity. Their advantageous properties compared to biological alternatives have sparked interest among scientists, as detailed in numerous review papers. Currently, there is significant attention on adhering to the principles of green chemistry and environmental protection. In this context, MIP research groups have focused on developing eco-friendly procedures. The application of "greener" monomers and reagents, along with the utilization of computational methodologies for design and property analysis, are two activities that align with the green chemistry principles for molecularly imprinted technology. This review discusses the application of computational methodologies in the preparation of MIPs based on eco-friendly non-acrylic/vinylic monomers and precursors, such as alkoxysilanes, ionic liquids, deep eutectic solvents, bio-based molecules-specifically saccharides, and biomolecules like proteins. It provides a brief introduction to MIP materials, the green aspects of MIP production, and the application of computational simulations. Following this, brief descriptions of the studied monomers, molecular simulation studies of green monomer-based MIPs, and computational strategies are presented. Finally, conclusions and an outlook on the future directions of computational analysis in the production of green imprinted materials are pointed out. To the best of my knowledge, this work is the first to combine these two aspects of MIP green chemistry principles.

1-Butyl-3-methylimidazolium-Based Ionic Liquid in Biomass Fractionation-Green Solvent or Active Reagent Toward Lignin Compounds?

N,N'-Dialkylimidazolium-based ionic liquids are capable of completely dissolving lignocellulosic biomass at elevated temperatures and are considered as promising green solvents for future biorefining technologies. However, the obtained ionic liquid lignin preparations may contain up to several percent nitrogen. This indicates strong interactions between the biopolymer and the IL cation, the nature of which has not yet been clarified. The present study investigates mechanisms and pathways of the formation of nitrogen-containing lignin compounds. To achieve this goal, eight monomeric lignin-related phenols bearing different functional groups (ketone, aldehyde, hydroxyl, carbon-carbon double bonds) were treated with 1-butyl-3-methylimidazolium acetate (BmimOAc) under typical conditions of IL-assisted lignocellulose fractionation (80-150 °C). A number of the resulting products were tentatively identified, for all the studied model compounds, by two-dimensional NMR spectroscopy and high-performance liquid chromatography-high-resolution mass spectrometry. They all possess covalently bonded Bmim residues and occur through the nucleophilic addition of an N-heterocyclic carbene (deprotonated Bmim cation) to electron-deficient groups. The reactivity of lignin functional groups in their interaction with Bmim is greatly affected by the temperature and dissolved oxygen. IL's thermal degradation products act as additional reactive species toward lignin, further complicating the range of products formed. The obtained results made it possible to answer the question posed in this article's title and to assert that N,N'-dialkylimidazolium-based ILs act as active reagents with respect to lignin during the dissolution of lignocellulose.

New emerging materials with potential antibacterial activities

The increasing prevalence of multidrug-resistant pathogens is a critical public health issue, necessitating the development of alternative antibacterial agents. Examples of these pathogens are methicillin-resistant Staphylococcus aureus (MRSA) and the emergence of "pan-resistant" Gram-negative strains, such as Pseudomonas aeruginosa and Acinetobacter baumannii, which occurred more recently. This review examines various emerging materials with significant antibacterial activities. Among these are nanomaterials such as quantum dots, carbon quantum dots, metal-organic frameworks (MOFs), covalent organic frameworks (COFs), and layered double hydroxides, all of which demonstrate excellent antibacterial properties. Interestingly, including antibacterial agents within the structure of these materials can help avoid bacterial resistance and improve the long-term efficacy of the materials. Additionally, the antibacterial potential of liquid solvents, including ionic liquids and both deep eutectic solvents and natural deep eutectic solvents, is explored. The review discusses the synthesis methods, advantages, and antibacterial efficacy of these new materials. By providing a comprehensive overview of these innovative materials, this review aims to contribute to the ongoing search for effective solutions to combat antibiotic resistance. Key studies demonstrating antibacterial effects against pathogens like Escherichia coli, Staphylococcus aureus, and multidrug-resistant strains are summarized. MOFs have exhibited antibacterial properties through controlled ion release and surface interactions. COFs have enhanced the efficacy of encapsulated antibiotics and displayed intrinsic antibacterial activity. Other nanomaterials, such as quantum dots, have generated reactive oxygen species, leading to microbial inactivation. This review aims to provide insights into these new classes of antibacterial materials and highlight them for addressing the global crisis of antibiotic resistance. KEY POINTS: • Nanomaterials show strong antibacterial effects against drug-resistant bacteria • Emerging solvents like ionic liquids offer novel solutions for bacterial resistance • MOFs and COFs enhance antibiotic efficacy, showing promise in combating resistance.

Advancements in ionic liquid-based corrosion inhibitors for sustainable protection strategies: from experimental to computational insights

The global corrosion cost is estimated to be around 2.5 trillion USD, which is more than 3 % of the global GDP. Against this background, large efforts have been made to find effective corrosion inhibitors. Ionic liquids (ILs) are nowadays regarded as reliable functional materials and one of the most promising classes of anticorrosion agents. Not only are they efficient in preventing corrosion of iron and other metals, but they are also relatively inexpensive, need no solvents, and are non-toxic to humans This review addresses both experimental and theoretical investigations conducted to IL-based corrosion inhibitors (CIs). It covers various ILs used, synthesis methods, and their performance in diverse corrosive environments. Electrochemical techniques like EIS and potentiodynamic polarization, along with computational approaches including quantum chemical calculations and DFT, provide valuable insights into corrosion inhibition mechanisms and the interactions between anticorrosion agents-surfaces. The synergistic combination of experimental and theoretical approaches enhances our understanding of corrosion inhibition, enabling the design and optimization of effective and sustainable corrosion protection strategies. This review consolidates the existing knowledge on ionic liquid-based corrosion inhibitors, highlights the key findings from both experimental and theoretical investigations, and points out possible directions for further studies in this area.

Exploration of supramolecular solvent-based microextraction for crystal violet detecting in water samples

This approach highlights the advantages of supramolecular solvents in a new microextraction model. The distinct properties and behavior of this supramolecular solvent provide enhanced extraction capabilities for detecting crystal violet (CV) in water samples. The methodical experimentation was executed to optimize the critical process parameters, providing maximum efficiency of crystal violet extraction at optimal conditions with pH set at 2.7, 186 μL of extraction solvent, extraction time of 3.5 min, and a salt amount of 3.1 % w/v, yielding the best results. Analytical data from extraction experiments under these optimal conditions demonstrated a high extraction percentage. The extraction model exhibited a linear response within the range of 10-800 ng mL-1 of crystal violet, with a detection limit of 2 ng mL-1. This model enables the measurement of CV in water samples with recovery rates exceeding 97 %, offering a straightforward and accessible approach for analysis.

Rapid and Environmentally-Friendly Synthesis of Thiazolidinone Analogues in Deep Eutectic Solvent Complemented with Computational Studies

A greener, safer, and more efficient methodology for the synthesis of (Z)-5-benzylidene-2-thioxothiazolidin-4-ones (3 a-u) and (Z)-5-benzylidenethiazolidine-2,4-diones (4 a-i) has been developed. The deep eutectic solvent (DES) ZnCl2/urea used as a greener solvent as well as a catalyst in this study accelerated the condensation of rhodanine and thiazolidine-2,4-dione with different aldehydes to afford the target scaffolds in excellent yields (88-98 %). The reaction methodology adopted offered significant advantages such as mild reaction conditions, functional group tolerance, quick reaction time, column-free isolation, catalytic recyclability, and applicability to gram-scale production. Moreover, density function theory calculations were carried out to investigate the global reactivity and stability profiles of these compounds. Finally, the green metrics analysis supported the greener nature of the present methodology.

A novel biological antibacterial polyvinyl alcohol/polyionic liquid hydrogel for wound dressing

The release of antibiotics or anions by traditional bacteriostatic agents led to the development of bacterial drug resistance and environmental pollution. Ionic liquids (ILs) have become important choices for antibacterial agents because of their excellent physical, chemical and biological properties. In this paper, the bioactivities of 1-vinyl-3-butylimidazolium chloride ([VBIM]Cl, IL) and poly (1-vinyl-3-butylimidazolium chloride) (P[VBIM]Cl, PIL) were evaluated, and the potential antibacterial material was used to synthesize hydrogels. Using the colony formation assay and the Oxford cup method, antibacterial effect of IL and PIL were tested. Cell-Counting-Kit-8 (CCK-8) experiments were used to study the IC50 (half maximal inhibitory concentration) values of IL and showed 1.47 mg/mL, 0.35 mg/mL and 0.33 mg/mL at 24 h, 48 h and 72 h, respectively. The IC50 value of PIL were 12.15 μg/mL, 12.06 μg/mL and 11.76 μg/mL at 24 h, 48 h and 72 h, respectively. The PIL is further crosslinked with polyvinyl alcohol (PVA) to form a novel hydrogel through freeze-thaw cycles. The newly fabricated hydrogel exhibited a high water content, excellent water absorption properties and outstanding mechanical performance. Using the colony formation assay and the inhibition zone assay, the hydrogels exhibited favorable antibacterial effects (against E.coli and S.aureus) such that nearly 100% of the bacteria were killed in liquid medium while cultivating with H4 (synthesized by 0.5 g PIL and 1g PVA). In addition, the cytotoxicity of PIL was significantly reduced through hydrogen bond crosslinking. H4 showed the highest antibacterial activity and a good biocompatibility. The results indicated that the PVA&PIL hydrogels had great potential for wound dressing.

Present status and application prospects of green chitin nanowhiskers: A comprehensive review

Petrochemical resources are non-renewable, which has impeded the development of synthetic polymers. The poor degradability of synthetic polymers poses substantial environmental pressure. Additionally, the high cost of synthetic biopolymers with excellent degradation performance limits their widespread application. Thus, it is crucial to seek green, sustainable, low-cost polymers as alternatives to petrochemical-based synthetic polymers and synthetic biopolymers. Chitin is a natural and renewable biopolymer discovered in crustacean shells, insect exoskeletons, and fungal cell walls. Chitin chains consist of crystalline and amorphous regions. Note that various treatments can be employed to remove the amorphous region, enhancing the crystallinity of chitin. Chitin nanowhiskers are a high crystallinity nanoscale chitin product with a high aspect ratio, a large surface area, adjustable surface morphology, and biocompatibility. They discover widespread applications in biomedicine, environmental treatment, food packaging, and biomaterials. Various methods can be utilized for preparing chitin nanowhiskers, including chemical, ionic liquids, deacetylation, and mechanical methods. However, developing an environmentally friendly preparation process remains a big challenge for expanding their applications in different materials and large-scale production. This article comprehensively analyzes chitin nanowhiskers' preparation strategies and their drawbacks. It also highlights the extensive application in different materials and various fields, besides the potential for commercial application.

Reshaping Capillary Electrophoresis With State-of-the-Art Sample Preparation Materials: Exploring New Horizons

Capillary electrophoresis (CE) is a powerful analysis technique with advantages such as high separation efficiency with resolution factors above 1.5, low sample consumption of less than 10 µL, cost-effectiveness, and eco-friendliness such as reduced solvent use and lower operational costs. However, CE also faces limitations, including limited detection sensitivity for low-concentration samples and interference from complex biological matrices. Prior to performing CE, it is common to utilize sample preparation procedures such as solid-phase microextraction (SPME) and liquid-phase microextraction (LPME) in order to improve the sensitivity and selectivity of the analysis. Recently, there have been advancements in the development of novel materials that have the potential to greatly enhance the performance of SPME and LPME. This review examines various materials and their uses in microextraction when combined with CE. These materials include carbon nanotubes, covalent organic frameworks, metal-organic frameworks, graphene and its derivatives, molecularly imprinted polymers, layered double hydroxides, ionic liquids, and deep eutectic solvents. The utilization of these innovative materials in extraction methods is being examined. Analyte recoveries and detection limits attained for a range of sample matrices are used to assess their effects on extraction selectivity, sensitivity, and efficiency. Exploring new materials for use in sample preparation techniques is important as it enables researchers to address current limitations of CE. The development of novel materials has the potential to greatly enhance extraction selectivity, sensitivity, and efficiency, thereby improving CE performance for complex biological analysis.

Fluorinated Linkers Enable High-Voltage Pyrrolidinium-based Dicationic Ionic Liquid Electrolytes

Novel fluorinated, pyrrolidinium-based dicationic ionic liquids (FDILs) as high-performance electrolytes in energy storage devices have been prepared, displaying unprecedented electrochemical stabilities (up to 7 V); thermal stability (up to 370 °C) and ion transport (up to 1.45 mS cm-1). FDILs were designed with a fluorinated ether linker and paired with TFSI/FSI counterions. To comprehensively assess the impact of the fluorinated spacer on their electrochemical, thermal, and physico-chemical properties, a comparison with their non-fluorinated counterparts was conducted. With a specific focus on their application as electrolytes in next-generation high-voltage lithium-ion batteries, the impact of the Li-salt on the characteristics of dicationic ILs was systematically evaluated. The incorporation of a fluorinated linker demonstrates significantly superior properties compared to their non-fluorinated counterparts, presenting a promising alternative towards next-generation high-voltage energy storage systems.

Vanadium-Containing Ionic Liquids Derived from Complexes of Modified Edta as Catalysts of Epoxy-Anhydride Ring-Opening Copolymerization

A new type of vanadium-containing ionic liquids (ILs) was synthesized by cation exchange from barium salts of oxidovanadium(IV) complexes stabilized by edta and its congeners (dcta, oedta, and heedta) serving as pentadentate ligands. All starting barium salts and several magnesium and cesium salts, serving as models for the cation exchange, were structurally characterized by single-crystal XRD analysis. The synthesized ILs consisting of organic cations (Bu4N+, Bmim+, and Bu4P+) and complex anions ([VO(edta)]2-, [VO(dcta)]2-, [VO(oedta)]-, and [VO(heedta)]-) were characterized by analytical and spectroscopic methods including EPR spectroscopy and cyclic voltammetry. Then, ILs were tested as catalysts for the ring-opening copolymerization of epoxy resin with cyclic anhydride showing significant catalytic activity, which led to production of highly cross-linked glassy thermosets. A detailed isothermal DSC kinetic study was performed for the most promising IL showing that the progress of cross-linking can be successfully fitted by the Kamal-Sourour model. Based on the DSC and NIR results, the initiation mechanism of the cross-linking in the presence of vanadium-containing IL was suggested. IL had ability to activate a rapid hydrolysis of anhydride cycle and the formed carboxyl groups initiated a polyesterification. In parallel, the role of imidazolium cation of IL for the initiation of chain-growth anionic copolymerization is also discussed.

Reactive capture and electrochemical conversion of CO2 with ionic liquids and deep eutectic solvents

Ionic liquids (ILs) and deep eutectic solvents (DESs) have tremendous potential for reactive capture and conversion (RCC) of CO2 due to their wide electrochemical stability window, low volatility, and high CO2 solubility. There is environmental and economic interest in the direct utilization of the captured CO2 using electrified and modular processes that forgo the thermal- or pressure-swing regeneration steps to concentrate CO2, eliminating the need to compress, transport, or store the gas. The conventional electrochemical conversion of CO2 with aqueous electrolytes presents limited CO2 solubility and high energy requirement to achieve industrially relevant products. Additionally, aqueous systems have competitive hydrogen evolution. In the past decade, there has been significant progress toward the design of ILs and DESs, and their composites to separate CO2 from dilute streams. In parallel, but not necessarily in synergy, there have been studies focused on a few select ILs and DESs for electrochemical reduction of CO2, often diluting them with aqueous or non-aqueous solvents. The resulting electrode-electrolyte interfaces present a complex speciation for RCC. In this review, we describe how the ILs and DESs are tuned for RCC and specifically address the CO2 chemisorption and electroreduction mechanisms. Critical bulk and interfacial properties of ILs and DESs are discussed in the context of RCC, and the potential of these electrolytes are presented through a techno-economic evaluation.

From Synthesis to Functionality: Tailored Ionic Liquid-Based Electrospun Fibers with Superior Antimicrobial Properties

Herein, we report an efficient and facile strategy for the preparation of imidazolium-based ionic liquid (IL) monomers ([CnVIm][Br], n = 2, 4, 6, 8, 10, and 12) and their corresponding polymeric ionic liquids (PILs) with potent antimicrobial activities against Gram-negative and Gram-positive bacteria and fungi. The electrospinning technique was utilized to tailor the polymers with the highest antimicrobial potency into porous membranes that can be easily implemented into diverse systems and extend their practical bactericidal application. The antimicrobial mechanism of obtained ILs, polymers, and nanomaterials is considered concerning the bearing chain length, polymerization process, and applied processing technique that provides a unique fibrous structure. The structure composition was selected due to the well-established inherent amphiphilicity that 1-alkylimidazolium ILs possess, coupled with proven antimicrobial, antiseptic, and antifungal behavior. The customizable nature of ILs and PILs complemented with electrospinning is exploited for the development of innovative antimicrobial performances born from the intrinsic polymer itself, offering solutions to the increasing challenge of bacterial resistance. This study opens up new prospects toward designer membranes providing a complete route in their designing and revolutionizing the approach of fabricating multi-functional systems with tunable physicochemical, surface properties, and interesting morphology.

Molecular simulation of [P8883][Tf2N] ionic liquid decorated silica in 6FDA-ODA based mixed matrix membrane for enhanced CO2/CH4 separation

Mixed-matrix membranes (MMMs) have been reported to have considerable scope in gas separation applications because of their merged inherent strength of a durable polymer matrix and the exceptional performance capabilities of inorganic fillers. The selection of comparatively suitable polymers with fillers that can match each other and boost interfacial compatibility while ensuring uniform dispersion of filler within the polymer is still intensively demanding and is challenging at the experimental scale. Ionic liquids (ILs) are effective in promoting better dispersion and compatibility, leading to improved separation performance. A computational molecular simulation approach is employed in current work to design a hybrid membrane having Trioctapropyl phosphonium bis(trifluoromethylsulfonyl)imide [P8883][Tf2N] IL decorated silica as a filler and 4,4'-(hexafluoroisopropylidene)diphthalic anhydride-4,4'-oxydianiline (6FDA-ODA) polymer for carbon dioxide (CO2) separation from methane (CH4). Thermophysical and gas transport properties under pure and mixed gas condition (30, 50, and 70% CO2/CH4) within the MMMs with varying filler loadings (5, 10, and 15 wt% IL-silica) are examined via Grand Canonical Monte Carlo (GCMC) and Molecular Dynamics (MD) simulations. Membrane characteristics like glass transition temperature (T g), Fractional Free Volume (v f), X-Ray Diffraction (XRD), solubility, diffusivity, permeability, and selectivity for neat and IL-silica filled 6FDA-ODA are computed. The results show that the T g of the composite membrane with 5 wt% IL-silica is found to be considerably higher (with 305 °C) than that of the pure 6FDA-ODA polymer having 298 °C. A higher T g value highlights the effective dispersion and higher adhesion between the filler and polymer membrane. Additionally, CO2 permeability for 5 wt% IL-silica/6FDA-ODA MMM is significantly improved, measuring 319.0 barrer while maintaining a CO2/CH4 selectivity of 16.2. These values are 89% and 56% respectively, greater than the corresponding values of neat 6FDA-ODA membrane. Published data from the literature review is used to validate the findings and guarantee their reliability. The obtained results exhibited an error in the range of 0.7-9%. Hence, it is concluded from the study that molecular simulation can be used to design IL decorated silica incorporated within 6FDA-ODA matrix, which is able to boost the interfacial compatibility, with elevated CO2/CH4 selectivity and CO2 permeability.

Ionic Liquids as Green and Efficient Desulfurization Media Aiming at Clean Fuel

With increasingly stringent emission limits on sulfur and sulfur-containing substances, the reduction and removal of sulfur compounds from fuels has become an urgent task. Emissions of sulfur-containing compounds pose a significant threat to the environment and human health. Ionic liquids (ILs) have attracted much attention in recent years as green solvents and functional materials, and their unique properties make them useful alternatives to conventional desulfurization organic solvents. This paper reviews the advantages and disadvantages of traditional desulfurization technologies such as hydrodesulfurization, oxidative desulfurization, biological desulfurization, adsorptive desulfurization, extractive desulfurization, etc. It focuses on the synthesis of ionic liquids and their applications in oxidative desulfurization, extractive desulfurization, extractive oxidative desulfurization, and catalytic oxidative desulfurization, and it analyzes the problems of ionic liquids that need to be solved urgently in desulfurization, looking forward to the development of sulfuric compounds as a kind of new and emerging green solvent in the field of desulfurization.

Keratin from Animal By-Products: Structure, Characterization, Extraction and Application-A Review

Keratin is a structural fibrous protein and the core constituent of animal by-products from livestock such as wool, feathers, hooves, horns, and pig bristles. This natural polymer is also the main component of human hair and is present at an important percentage in human and animal skin. Significant amounts of keratin-rich animal tissues are discarded worldwide each year, ca. 12 M tons, and the share used for keratin extraction and added-value applications is still very low. An important stream of new potential raw materials, represented by animal by-products and human hair, is thus being lost, while a large-scale valorization could contribute to a circular bioeconomy and to the reduction in the environmental fingerprint of those tissues. Fortunately, scientific research has made much important progress in the last 10-15 years in the better understanding of the complex keratin architecture and its variability among different animal tissues, in the development of tailored extraction processes, and in the screening of new potential applications. Hence, this review aims at a discussion of the recent findings in the characterization of keratin and keratin-rich animal by-product structures, as well as in keratin recovery by conventional and emerging techniques and advances in valorization in several fields.

Experimental Study on the Transport Properties of 12 Novel Deep Eutectic Solvents

Deep eutectic solvents (DESs) are complex substances composed of two or three components, wherein hydrogen bond donors and acceptors engage in intricate interactions within a hydrogen bond network. They have attracted extensive attention from researchers due to their easy synthesis, cost-effectiveness, broad liquid range, good stability, and for being green and non-toxic. However, studies on the physical properties of DESs are still scarce and many theories are not perfect enough, which limits the application of DESs in engineering practice. In this study, twelve DESs were synthesized by using choline chloride and betaine as HBAs, and ethylene glycol, polyethylene glycol 600, o-cresol, glycerol, and lactic acid as HBDs. The variation rules of their thermal conductivity and viscosity with temperature at atmospheric pressure were systematically investigated. The experimental results showed that the thermal conductivity of the 1:4 choline chloride/glycerol solvent was the largest at 294 K, reaching 0.2456 W·m-1·K-1, which could satisfy the demand for high efficiency heat transfer by heat-transferring workpieces. The temperature-viscosity relationship of the DESs was fitted using the Arrhenius model, and the maximum average absolute deviation was 6.77%.

Small Ionic-Liquid-Based Molecule Drives Strong Adhesives

Nature has inspired scientists to fabricate adhesive materials for applications in many burgeoning areas. However, it is still a significant challenge to develop small-molecule adhesives with high-strength, low-temperature and recyclable properties, although these merits are of great interest in various aspects. Herein, we report a series of strong adhesives based on low-molecular-weight molecular solids driven by the terminal modification of ionic liquids (ILs) and subsequent supramolecular self-assembly. The emergence of high strength and liquid-to-solid transitions for these supramolecular aggregates relies on modifying IL with a high melting point motif and enriching the types of noncovalent interactions in the original ILs. Using this strategy, we demonstrate that our IL-based molecular solids can efficiently obtain a high adhesion strength (up to 8.95 MPa). Importantly, we elucidate the mechanism underlying the reversible and strong adhesion enabled by monomer-to-polymer transitions. These fundamental findings provide guidance for the design of high-performance supramolecular adhesive materials.

The Cohesive Interactions in Phenylimidazoles

This work presents a comprehensive study exploring the thermodynamics of the solid phase of a series of phenylimidazoles, encompassing experimental measurements of heat capacity, volatility, and thermal behavior. The influence of successive phenyl group insertions on the imidazole ring on thermodynamic properties and supramolecular behavior was thoroughly examined through the evaluation of 2-phenylimidazole (2-PhI), 4-phenylimidazole (4-PhI), 4,5-diphenylimidazole (4,5-DPhI), and 2,4,5-triphenylimidazole (2,4,5-TPhI). Structural correlations between molecular structure and thermodynamic properties were established. Furthermore, the investigation employed UV-vis spectroscopy and quantum chemical calculations. Additive effects arising from the introduction of phenyl groups were found through the analysis of the solid-liquid and solid-gas equilibria, as well as heat capacities. A good correlation emerged between the thermodynamic properties of sublimation and the molar volume of the unit cell, evident across 2-PhI, 4,5-DPhI, and 2,4,5-TPhI. In contrast to its isomer 2-PhI, 4-PhI exhibited greater cohesive energy due to the stronger N-H···N intermolecular interactions, leading to the disruption of coplanar geometry in the 4-PhI molecules. The observed higher entropies of phase transition (fusion and sublimation) are consistent with the higher structural order observed in the crystalline lattice of 4-PhI.

Oxidative and Extractive Desulfurization of Fuel Oils Catalyzed by N-Carboxymethyl Pyridinium Acetate and N-Carboxyethyl Pyridinium Acetate Acidic Ionic Liquids: Experimental and Computational DFT Study

This study reports on the synthesis, characterization, and application of two acidic ionic liquids, namely, N-carboxymethylpyridinium acetate ([HO2CCH2Py][CH3CO2] or AIL1) and N-carboxyethylpyridinium acetate ([HO2C(CH2)2Py][CH3CO2] or AIL2), as both extractants and catalysts for the oxidative and extractive desulfurization (OEDS) of model fuel oils containing heteroaromatic sulfur compounds. The structural properties of the synthesized acidic ionic liquids (ILs) were confirmed by 1H NMR, 13C NMR, and FT-IR spectroscopic analysis. To optimize the performance of the acidic AILs in the desulfurization process, the effects of different parameters, such as H2O2 dosage, reaction time, and temperatures, were investigated. The experimental results showed that AIL1 has exceptionally high desulfurization-extraction rates, with values of 99.8%, 97.8%, and 95.4%, for DBT, BT, and 4,6-DMDBT, respectively, under the optimum conditions established. Under the same conditions, the desulfurization-extraction rates using AIL2 reached 91.6%, 87.3%, and 82.4%, respectively, for DBT, 4, 6-DMDBT, and BT. Both ionic liquids can be recycled up to 9 times without a significant decrease in their sulfur removal efficiencies. Furthermore, density functional theory (DFT) calculations were conducted to evaluate the electronic interaction energies (ΔIE) between the AILs with each of the sulfur-containing compounds and their putative oxidized products. The computational findings strongly supported the experimental outcomes.

Bioconcentration potential of ionic liquids: New data on membrane partitioning and its comparison with predictions obtained by COSMOmic

Ionic liquids (ILs) have recently gained significant attention in both the scientific community and industry, but there is a limited understanding of the potential risks they might pose to the environment and human health, including their potential to accumulate in organisms. While membrane and storage lipids have been considered as primary sorption phases driving bioaccumulation, in this study we used an in vitro tool known as solid-supported lipid membranes (SSLMs) to investigate the affinity of ILs to membrane lipid - phosphatidylcholine and compare the results with an existing in silico model. Our findings indicate that ILs may have a strong affinity for the lipids that form cell membranes, with the key factor being the length of the cation's side chain. For quaternary ammonium cations, increase in membrane affinity (logMA) was observed from 3.45 ± 0.06 at 10 carbon atoms in chain to 4.79 ± 0.06 at 14 carbon atoms. We also found that the anion can significantly affect the membrane partitioning of the cation, even though the anions themselves tend to have weaker interactions with phospholipids than the cations of ILs. For 1-methyl-3-octylimidazolium cation the presence of tricyanomethanide anion caused increase in logMA to 4.23 ± 0.06. Although some of our data proved to be consistent with predictions made by the COSMOmic model, there are also significant discrepancies. These results suggest that further research is needed to improve our understanding of the mechanisms and structure-activity relationships involved in ILs bioconcentration and to develop more accurate predictive models.

New biologically active ionic liquids with benzethonium cation-efficient SAR inducers and antimicrobial agents

BACKGROUND

An urgent need to find new methods for crop protection remains open due to the withdrawal from the market of the most toxic pesticides and increasing consumer awareness. One of the alternatives that can be used in modern agriculture is the use of bifunctional compounds whose actions towards plant protection are wider than those of conventional pesticides.

RESULTS

In this study, we present the investigation of the biological efficacy of nine dual-functional salts containing a systemic acquired resistance (SAR)-inducing anion and the benzethonium cation. A significant result of the presented study is the discovery of the SAR induction activity of benzethonium chloride, which was previously reported only as an antimicrobial agent. Moreover, the concept of dual functionality was proven, as the application of presented compounds in a given concentrations resulted both in the control of human and plant bacteria species and induction of SAR.

CONCLUSION

The strategy presented in this article shows the capabilities of derivatization of common biologically active compounds into their ionic derivatives to obtain bifunctional salts. This approach may be an example of the design of potential new compounds for modern agriculture. It provides plants with two complementary actions allowing to provide efficient protection to plants, if one mode of action is ineffective. © 2024 Society of Chemical Industry.

Pretreatment of wastepaper with an aqueous solution of amino acid-derived ionic liquid for biochar production as adsorbent

The carbonization of lignocellulosic biomass with ionic liquids (ILs) are considered as an advantageous approach for the preparation of carbonaceous materials. The commonly used imidazolium and pyridinium based ILs have drawbacks such as toxicity, resistance to biodegradation, high cost and viscosity. These issues can be mitigated by diluting ILs with water, although excessive water content above 1 wt% can reduce the solubility of biomass. This research aims to investigate the potential of pretreating wastepaper with a "fully green" ILs, amino acid-based IL with high water content, followed by pyrolysis without IL, in enhancing the properties of biochar. For this purpose, the paper was treated with an aqueous solution of IL cysteine nitrate ([Cys][NO3]), and the IL was not involved in the pyrolysis process to prevent the formation of secondary gaseous pollutants. The findings revealed that the hemicellulose and mineral filler in the paper were eliminated during pretreatment, leading to higher carbon content but lower oxygen content. As a result, the biochar exhibited micropores of 0.42 cm3g-1 and a specific surface area of 1011.21 m2 g-1. The biochar demonstrated high adsorption capacities for Cd2+, enrofloxacin, bisphenol A, ciprofloxacin, and tetracycline, with values of 45.20 mg g-1, 49.82 mg g-1, 49.90 mg g-1, 49.88 mg g-1, and 49.65 mg g-1, respectively. The proposed mechanism for the adsorption of enrofloxacin by the biochar primarily involves physical adsorption such as pore filling and electrostatic interactions, along with chemical adsorption facilitated by graphitic nitrogen.

Development of a New Aggregation Method to Remove Nanoplastics from the Ocean: Proof of Concept Using Mussel Exposure Tests

The overproduction and mismanagement of plastics has led to the accumulation of these materials in the environment, particularly in the marine ecosystem. Once in the environment, plastics break down and can acquire microscopic or even nanoscopic sizes. Given their sizes, microplastics (MPs) and nanoplastics (NPs) are hard to detect and remove from the aquatic environment, eventually interacting with marine organisms. This research mainly aimed to achieve the aggregation of micro- and nanoplastics (MNPs) to ease their removal from the marine environment. To this end, the size and stability of polystyrene (PS) MNPs were measured in synthetic seawater with the different components of the technology (ionic liquid and chitosan). The MPs were purchased in their plain form, while the NPs displayed amines on their surface (PS NP-NH2). The results showed that this technology promoted a significant aggregation of the PS NP-NH2, whereas, for the PS MPs, no conclusive results were found, indicating that the surface charge plays an essential role in the MNP aggregation process. Moreover, to investigate the toxicological potential of MNPs, a mussel species (M. galloprovincialis) was exposed to different concentrations of MPs and NPs, separately, with and without the technology. In this context, mussels were sampled after 7, 14, and 21 days of exposure, and the gills and digestive glands were collected for analysis of oxidative stress biomarkers and histological observations. In general, the results indicate that MNPs trigger the production of reactive oxygen species (ROS) in mussels and induce oxidative stress, making gills the most affected organ. Yet, when the technology was applied in moderate concentrations, NPs showed adverse effects in mussels. The histological analysis showed no evidence of MNPs in the gill's tissues.

Atomistic molecular dynamics simulation and COSMO-SAC approach for enhanced 1,3-propanediol extraction with imidazolium-based ionic liquids

CONTEXT

1,3-Propanediol (1,3-PDO) is a key chemical in various industries, including pharmaceuticals and material sciences, and is projected to see significant market growth. However, the current challenges in its downstream processing, particularly in terms of cost and efficiency, highlight the need for innovative solutions. Our study delves into using ionic liquids (ILs) as a potential alternative, aiming to address these critical separation challenges more sustainably and efficiently. In this study, we utilized molecular dynamics (MD) simulations and the COSMO-SAC to examine 1,3-propanediol (1,3-PDO) extraction using four imidazolium-based ionic liquids with 1-butyl-3-methylimidazolium [Bmim] cation and with different anions bis(pentafluoroethanesulfonyl)imide [NPF2]-, bis(trifluoromethylsulfonyl)imide [NTF2]-, thiocyanate [SCN]-, and trifluoromethanesulfonate [TFO]-. Molecular dynamics simulations, incorporating analysis of radial distribution functions (RDF) and spatial distribution functions (SDF), revealed that [Bmim][SCN] and [Bmim][TFO] exhibit enhanced interactions with 1,3-PDO. Notably, [Bmim][SCN] formed the most hydrogen bonds, averaging 1.639 per molecule, due to its coordinating [SCN]- anion. This was in contrast to the fewer hydrogen bonds formed by non-coordinating anions in [Bmim][NPF2] and [Bmim][NTF2]. In ternary systems, [Bmim][SCN] and [Bmim][TFO] demonstrated superior selectivity for 1,3-PDO extraction compared to the other ionic liquids, with selectivity values around 29. These findings, supported by COSMO-SAC predictive modeling, highlight the potential of [Bmim][SCN] as a promising candidate for 1,3-PDO extraction, emphasizing the importance of anion selection in optimizing ionic liquid properties for this application.

METHODS

In our study, we employed MD simulations, incorporating the OPLS-AA force field, and COSMO-SAC to investigate the extraction of 1,3-PDO using imidazolium-based ionic liquids: [Bmim][NTF2], [Bmim][NPF2], [Bmim][SCN], and [Bmim][TFO]. The MD simulations were conducted using LAMMPS software, focusing on elucidating the RDF, SDF, and hydrogen bonding. Analysis of the distribution coefficient (β) and selectivity (S) for the ternary mixture was also conducted. These aspects of the simulation were analyzed using TRAVIS and VMD software. Additionally, the COSMO-SAC model was employed to determine the activity coefficients of 1,3-PDO in the ionic liquids, with molecular optimization conducted using Gaussian16 and sigma profile calculations performed using COSMO-SAC.

A Combined Experimental/Computational Study of Dicationic Ionic Liquids with Bromide and Tungstate Anions

A panel of dicationic ionic liquids (DILs) with different rigid xylyl (ortho, meta, para) spacers and different anions (bromide and tungstate) has been synthetised and characterised through different experimental and computational techniques. Differences and analogies between the systems are analysed using information derived from their DFT structures, semiempirical dynamics, thermal behaviour, and catalytic properties versus the well-known reaction of CO2 added to epichlorohydrin. A comparison between the proposed systems and some analogues that present non-rigid spacers shows the key effect displayed by structure rigidity on their characteristics. The results show an interesting correlation between structure, flexibility, properties, and catalytic activity.

Effect of Amino Acid Types on the Mechanical and Antimicrobial Properties of Amino Acid-Based Polyionic Liquid Hydrogels

Polyionic liquid hydrogels attract increasing attention due to their unique properties and potential applications. However, research on amino acid-based polyionic liquid hydrogels is still in its infancy stage. Moreover, the effect of amino acid types on the properties of hydrogels is rarely studied to date. In this work, amino acid-based polyionic liquid hydrogels (D/L-PCAA hydrogels) are synthesized by copolymerizing vinyl choline-amino acid ionic liquids and acrylic acids using Al3+ as a crosslinking agent and bacterial cellulose (BC) as a reinforcing agent. The effects of amino acid types on mechanical and antimicrobial properties are systematically investigated. D-arginine-based hydrogel (D-PCArg) shows the highest tensile strength (220.7 KPa), D-phenylalanine-based hydrogel (D-PCPhe) exhibits the highest elongation at break (1346%), and L-aspartic acid-based hydrogel (L-PCAsp) has the highest elastic modulus (206.9 KPa) and toughness (1.74 MJ m-3). D/L-PCAsp hydrogels demonstrate stronger antibacterial capacity against Escherichia coli and Staphylococcus aureus, and D/L-PCPhe hydrogels possess higher antifungal activity against Cryptococcus neoformans. Moreover, the resultant hydrogels exhibit prominent hemocompatibility and low toxicity, as well as excellent self-healing capabilities (86%) and conductivity (2.8 S m-1). These results indicate that D/L-PCAA hydrogel provides a promise for applications in wound dressings.

Ionothermal Carbonization of Sugarcane Bagasse in 1-Alkyl-3-methylimidazolium Ionic Liquids: Insights into the Role of the Chloroferrate Anion

We report the ionothermal carbonization (ITC) of lignocellulosic biomass in imidazolium tetrachloroferrate ionic liquids (ILs) as an advantageous approach for the preparation of nanostructured carbonaceous materials, namely, ionochars. In a previous study, we investigated the role of the imidazolium cation and demonstrated the possibility of controlling both the textural and morphological properties of ionochars by cation engineering. Although essential for providing intermediate Lewis acidity and relatively high thermal stability, the role of the chloroferrate anion is still open to debate. Herein, we investigated the ITC of sugarcane bagasse and its main component, cellulose, in 1-alkyl-3-methylimidazolium ILs with different chloroferrate anions. We identified anionic speciation and its impact on the properties of the IL by Raman spectroscopy, thermogravimetric analysis, and differential scanning calorimetry. The obtained ionochars were characterized by gas physisorption, electron microscopy, Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and 13C solid-state CP-MAS NMR spectroscopy. We show that the anionic species have a predominant impact on the textural and morphological properties of the ionochars.

New Insights into the Hygroscopic Character of Ionic Liquids: Study of Fourteen Representatives of Five Cation and Four Anion Families

Over the past three decades, the synthesis of new ionic liquids (ILs) and the expansion of their use in newer applications have grown exponentially. From the beginning of this vertiginous period, it was known that many of them were hygroscopic, which in some cases limited their use or altered the value of their measured physical properties with all the problems that this entails. In an earlier article, we addressed the hygroscopic grade achieved by the ILs 1-ethyl-3-methylimidazolium chloride, 1-ethyl-3-methylimidazolium bromide, 1-ethyl-3-methylimidazolium methyl sulfate, 1-ethyl-3-methylimidazolium ethyl sulfate, 1-ethyl-3-methylpyridinium ethyl sulfate, 1-ethyl-3-methylimidazolium tosylate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-dodecyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylpyridinium tetrafluoroborate, 1-butyl-1-methylpiperidinium bis(trifluoromethyl sulfonyl)imide, 1-methyl-1-propylpyrrolidinium bis(trifluoromethyl sulfonyl)imide, 1-butyl-1-methylpyrrolidinium bis(trifluoromethyl sulfonyl)imide, and methyl trioctyl ammonium bis(trifluoromethyl sulfonyl)imide. The objective was to determine the influence of the chemical nature of the compounds, exposed surface area, sample volume, agitation, and temperature. For this purpose, we exposed the samples to abrupt increases in relative humidity from 15 to 100% for days in an atmosphere chamber and then proceeded with the reverse process in a gentle manner. The results show that the sorption of water from the atmosphere depends on the nature of the IL, especially the anion, with the chloride anion being of particular importance (chloride ≫ alkyl sulfates~bromide > tosylate ≫ tetrafluoroborate). It has also been proven for the EMIM-ES and EMIM-BF4 samples that the mechanism of moisture capture is both absorption and adsorption, and that the smaller the exposed surface area, the higher the ratio of the mass of water per unit area.

Polymerized and Colloidal Ionic Liquids─Syntheses and Applications

The breadth and importance of polymerized ionic liquids (PILs) are steadily expanding, and this review updates advances and trends in syntheses, properties, and applications over the past five to six years. We begin with an historical overview of the genesis and growth of the PIL field as a subset of materials science. The genesis of ionic liquids (ILs) over nano to meso length-scales exhibiting 0D, 1D, 2D, and 3D topologies defines colloidal ionic liquids, CILs, which compose a subclass of PILs and provide a synthetic bridge between IL monomers (ILMs) and micro to macro-scale PIL materials. The second focus of this review addresses design and syntheses of ILMs and their polymerization reactions to yield PILs and PIL-based materials. A burgeoning diversity of ILMs reflects increasing use of nonimidazolium nuclei and an expanding use of step-growth chemistries in synthesizing PIL materials. Radical chain polymerization remains a primary method of making PILs and reflects an increasing use of controlled polymerization methods. Step-growth chemistries used in creating some CILs utilize extensive cross-linking. This cross-linking is enabled by incorporating reactive functionalities in CILs and PILs, and some of these CILs and PILs may be viewed as exotic cross-linking agents. The third part of this update focuses upon some advances in key properties, including molecular weight, thermal properties, rheology, ion transport, self-healing, and stimuli-responsiveness. Glass transitions, critical solution temperatures, and liquidity are key thermal properties that tie to PIL rheology and viscoelasticity. These properties in turn modulate mechanical properties and ion transport, which are foundational in increasing applications of PILs. Cross-linking in gelation and ionogels and reversible step-growth chemistries are essential for self-healing PILs. Stimuli-responsiveness distinguishes PILs from many other classes of polymers, and it emphasizes the importance of segmentally controlling and tuning solvation in CILs and PILs. The fourth part of this review addresses development of applications, and the diverse scope of such applications supports the increasing importance of PILs in materials science. Adhesion applications are supported by ionogel properties, especially cross-linking and solvation tunable interactions with adjacent phases. Antimicrobial and antifouling applications are consequences of the cationic nature of PILs. Similarly, emulsion and dispersion applications rely on tunable solvation of functional groups and on how such groups interact with continuous phases and substrates. Catalysis is another significant application, and this is an historical tie between ILs and PILs. This component also provides a connection to diverse and porous carbon phases templated by PILs that are catalysts or serve as supports for catalysts. Devices, including sensors and actuators, also rely on solvation tuning and stimuli-responsiveness that include photo and electrochemical stimuli. We conclude our view of applications with 3D printing. The largest components of these applications are energy related and include developments for supercapacitors, batteries, fuel cells, and solar cells. We conclude with our vision of how PIL development will evolve over the next decade.

Effects of imidazolium ionic liquids on skin barrier lipids - Perspectives for drug delivery

Ionic liquids (ILs) have great potential to facilitate transdermal and topical drug delivery. Here, we investigated the mechanism of action of amphiphilic ILs 1-methyl-3-octylimidazolium bromide (C8MIM) and 3-dodecyl-1-methylimidazolium bromide (C12MIM) in skin barrier lipid models in comparison to their complex effects in human skin. C8MIM incorporated in a skin lipid model was a better permeation enhancer than C12MIM for water and model drugs, theophylline and diclofenac. Solid state 2H NMR and X-ray diffraction indicated that both ILs prefer the cholesterol-rich regions in skin lipids without significantly perturbing their lamellar arrangement and that C8MIM induces the formation of an isotropic lipid phase to a greater extent compared to C12MIM. C12MIM applied topically to the lipid model or human skin as a pretreatment was more potent than C8MIM. When co-applied with the drugs to human skin, aqueous C12MIM was more potent than C8MIM in enhancing theophylline permeation, but neither IL affected (even decreased) diclofenac permeation. Thus, the IL's ability to permeabilize skin lipid barrier is strongly modulated by its ability to reach the site of action and its interactions with drug and solvent. Such an interplay is far from trivial and requires detailed investigation to realize the full potential of ILs.

Fabrication of ionic liquid functionalized silica with different anions and the application in mixed-mode and chiral chromatography

To realize the potential of ionic liquid functionalized silica to prepare mixed-mode and chiral stationary phases, two ionic liquid silane reagents with different anions were synthesized via a high-efficiency click reaction. Then they were decorated onto the surface of silica by a one-step bonding reaction. The functionalized silica was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and elemental analysis (EA). Two stationary phases provided satisfactory performance when compared with a commercial mixed-mode column. Notably, Sil-C10Im-D-BCS with D-3-bromocamphor-8-sulfonate (D-BCS) as anion presented chiral separation capacity towards 1,2,3,4-Tetrahydro-1-naphthol. The separation mechanism was investigated through multiple pathways, and the results revealed that the prepared stationary phases can retain and separate solutes through multiple interactions, like hydrophobic effect, ion exchange, hydrogen-bond interaction, etc. Quantum chemical calculation (QC) was employed to obtain the optimized structures and the binding energy of anions to cations. The results provided some insights into the retention mechanism from a molecular perspective. This work demonstrated the superiority of ionic liquid functionalized silica as mixed-mode stationary phases and the potential of chiral ionic liquid as chiral selectors.

Biophysical Characterization and Cryopreservation of Mammalian Cells Using Ionic Liquids

Ionic liquids (ILs) are a diverse class of solvents which can be selected for task-specific properties, making them attractive alternatives to traditional solvents. To tailor ILs for specific biological applications, it is necessary to understand the structure-property relationships of ILs and their interactions with cells. Here, a selection of carboxylate anion-based ILs were investigated as cryoprotectants, which are compounds added to cells before freezing to mitigate lethal freezing damage. The cytotoxicity, cell permeability, thermal behavior, and cryoprotective efficacy of the ILs were assessed with two model mammalian cell lines. We found that the biophysical interactions, including permeability of the ILs, were influenced by considering the IL pair together, rather than as single species acting independently. All of the ILs tested had high cytotoxicity, but ethylammonium acetate demonstrated good cryoprotective efficacy for both cell types tested. These results demonstrate that despite toxicity, ILs may be suitable for certain biological applications. It also demonstrates that more research is required to understand the contribution of ion pairs to structure-property relationships and that knowing the behavior of a single ionic species will not necessarily predict its behavior as part of an IL.

Effect of Pore Confinement of Ionic Liquids on Solute Diffusion within Mesoporous Silica Microparticles

The transport properties of the ionic liquid (IL) 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]) confined within silica microparticles with well-ordered, accessible mesopores (5.4 or 9 nm diameter) were investigated. [BMIM][PF6] confinement was confirmed by using differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy. The transport properties of the confined IL were studied using the neutral and cationic fluorescent probes 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM) and rhodamine 6G, respectively, through fluorescence recovery after photobleaching (FRAP) in confocal microscopy. The diffusivity of DCM in 9 nm pores is 0.026 ± 0.0091 μm2/s, which is 2 orders of magnitude less than in the bulk ionic liquid. The pore size did not affect the diffusivity of DCM in unmodified silica nanopores. The diffusivity of the cationic probe is reduced by 63% relative to that of the neutral probe. Diffusivity is increased with water content, where equilibrium hydration of the system leads to a 37% increase in DCM diffusivity. The most dramatic impact on diffusivity was caused by tethering an IL-like methylimidazolium chloride group to the pores, which increased the pore hydrophobicity and resulted in 3-fold higher diffusivity of DCM compared to bare silica pores. Subsequent exchange of the chloride anion from the tethering group with PF6- decreased the diffusivity to half that of bare silica. The diffusion of probe molecules is affected most strongly by the pore wall effects on probe interactions rather than by the pore size itself, which suggests that understanding pore wall diffusion is critical to the design of nanoconfined ILs for separations, catalysis, and energy storage.

Tunable Zeolitic Imidazolate Framework-8 Nanoparticles for Biomedical Applications

Zeolite imidazole framework-8 (ZIF-8) is the most prestigious one among zeolitic imidazolate framework (ZIF) with tunable dimensions and unique morphological features. Utilizing its synthetic adjustability and structural regularity, ZIF-8 exhibits enhanced flexibility, allowing for a wide range of functionalities, such as loading of nanoparticle components while preserving biomolecules activity. Extensive efforts are made from investigating synthesis techniques to develop novel applications over decades. In this review, the development and recent progress of various synthesis approaches are briefly summarized. In addition, its interesting properties such as adjustable porosity, excellent thermal, and chemical stabilities are introduced. Further, five representative biomedical applications are highlighted based on above physicochemical properties. Finally, the remaining challenges and offered insights into the future outlook are also discussed. This review aims to understand the co-relationships between structures and biomedical functionalities, offering the opportunity to construct attractive materials with promising characteristics.

Advances in ionic liquids as fluorescent sensors

Ionic liquids (ILs) are a class of liquid salts with characteristics such as a low melting point, an ionic nature, non-volatility, and tunable properties. Because of their adaptability, they have a significant influence in the field of fluorescence. This paper reviews the primary literature on the use of ILs in fluorescence sensing technologies. The kind of target material is utilized to classify the fluorescence sensors made with the use of ILs. They include using ILs as probes for metals, nitro explosives, small organic compounds, anions, and gases. The efficacy of an IL-based fluorescence sensor depends on the precise design to guarantee specificity, sensitivity, and a consistent reaction to the desired analyte. The precise method can differ depending on the chemical properties of the IL, the choice of fluorophore, and the interactions with the analyte. Overall, the viability of the aforementioned materials for chemical analysis is evaluated, and prospective possibilities for further development are identified.

Nanomagnetic Cyclodextrin decorated with ionic liquid as green and reversible Demulsifier for breaking of crude oil emulsions

Application of the chemical demulsifiers is the best choice for breaking the water in crude oil (W/O) emulsions in the petroleum industry. Here, novel, environmentally friendly, efficient, and easily reusable Fe3O4 nanomagnetic compounds based on imidazolium-decorated cyclodextrin were successfully synthesized and applied to demulsify the water in crude oil (W/O) emulsions. At first, Fe3O4 nanoparticles were decorated with β-cyclodextrin (β-CD) to prepare Fe3O4@β-CD@IL magnetic nanoparticles. Then, imidazole (Im) was separately reacted with 1-bromohexane and 1-bromodecane to prepare [Im-C6][Br] and [Im-C10][Br] ionic liquids, respectively. The prepared imidazolium-based ionic liquids were reacted with N-propyltriethoxysilane to synthesize [ImSi-C6][Br] and [ImSi-C10][Br]. Finally, [ImSi-Cn][Br] was immobilized on Fe3O4@β-CD to obtain nanomagnetic demulsifiers. Structure of the synthesized compounds was confirmed using different methods such as FT-IR, NMR, and elemental analysis. TGA, VSM, and FESEM methods were used to investigate the thermal stability, magnetic properties, and the morphology, respectively. Fe3O4@βCD and Fe3O4@βCD@[ImSi-C10][Br] nanoparticles respectively showed the particle size in the range of 40-70 nm and 50-80 nm. After grafting the imidazolium-based ionic liquid on the surface of support, the magnetization number reduced from 25.6 emu/g for Fe3O4@β-CD to 24.9 emu/g for Fe3O4@β-CD@[ImSi-C10][Br]. Synthesized material employed to break the (10:90 and 30:70 Vol%) W/O emulsions at the concentration range of 1000-5000 ppm. The maximum demulsification efficiency (DE%) of 92 % was obtained using a Fe3O4@β-CD@[ImSi-C10][Br] at 5000 ppm for (30:70 Vol%) W/O emulsion within 24 h. Interfacial tension (IFT) values decreased with increasing the DE%. The Fe3O4@βCD@[ImSi-C10][Br] demulsifier was reused five times with acceptable yields. The cooperation of imidazolium and β-CD in the green nanomagnetic demulsifiers led to the efficient demulsification of the W/O emulsions. The preparation of different ionic liquids or changing the counter anions are our potential future directions for this research. Demulsification at high demulsifier concentration can be considered a limitation of the nanomagnetic cyclodextrin decorated with ionic liquid. But due to the low amount of ionic liquid immobilized in the synthesized demulsifier, the cost of the final demulsifier is lower that other demulsifiers with full ionic liquid backbones, which increases its potential for industrial applications.

Process Simulation and Optimization on Ionic Liquids

Ionic liquids (ILs) are promising alternative compounds that enable the development of technologies based on their unique properties as solvents or catalysts. These technologies require integrated product and process designs to select ILs with optimal process performances at an industrial scale to promote cost-effective and sustainable technologies. The digital era and multiscale research methodologies have changed the paradigm from experiment-oriented to hybrid experimental-computational developments guided by process engineering. This Review summarizes the relevant contributions (>300 research papers) of process simulations to advance IL-based technology developments by guiding experimental research efforts and enhancing industrial transferability. Robust simulation methodologies, mostly based on predictive COSMO-SAC/RS and UNIFAC models in Aspen Plus software, were applied to analyze key IL applications: physical and chemical CO2 capture, CO2 conversion, gas separation, liquid-liquid extraction, extractive distillation, refrigeration cycles, and biorefinery. The contributions concern the IL selection criteria, operational unit design, equipment sizing, technoeconomic and environmental analyses, and process optimization to promote the competitiveness of the proposed IL-based technologies. Process simulation revealed that multiscale research strategies enable advancement in the technological development of IL applications by focusing research efforts to overcome the limitations and exploit the excellent properties of ILs.

Hybrid Improved Grey Wolf Support Vector Regression Algorithm for Modeling Solubilities of APIs in Pure Ionic Liquids: σ-Profile Descriptors

The objective of this study was to model the solubility of active pharmaceutical ingredients (APIs) in different ionic liquids (ILs) based on the σ-moments of cations, anions, and APIs that were used as molecular descriptors calculated using the σ-profiles of three categories of descriptors based on conductor-like screening model for real solvents. The database of 83 API-ILs systems composed of 14 APIs, 12 cations, and 7 anions (25 ILs combinations) was collected as 850 data points at different temperature ranges. A hybrid Improved Grey Wolf Support vector regression, abbreviated as I-GWO-SVR(r), algorithm was selected as the learning method. Based on a comprehensive comparison with 11 different models, various statistical factors, and graphical analyses, including an external validation test, analysis of variance (ANOVA), and sensitivity analysis, the capability and validity of the proposed approach have been assessed and verified. The overall study confirmed that the proposed new model provided the best results in terms of predicting the solubility of APIs in ILs.

Predicting the formation of NADES using a transformer-based model

The application of natural deep eutectic solvents (NADES) in the pharmaceutical, agricultural, and food industries represents one of the fastest growing fields of green chemistry, as these mixtures can potentially replace traditional organic solvents. These advances are, however, limited by the development of new NADES which is today, almost exclusively empirically driven and often derivative from known mixtures. To overcome this limitation, we propose the use of a transformer-based machine learning approach. Here, the transformer-based neural network model was first pre-trained to recognize chemical patterns from SMILES representations (unlabeled general chemical data) and then fine-tuned to recognize the patterns in strings that lead to the formation of either stable NADES or simple mixtures of compounds not leading to the formation of stable NADES (binary classification). Because this strategy was adapted from language learning, it allows the use of relatively small datasets and relatively low computational resources. The resulting algorithm is capable of predicting the formation of multiple new stable eutectic mixtures (n = 337) from a general database of natural compounds. More importantly, the system is also able to predict the components and molar ratios needed to render NADES with new molecules (not present in the training database), an aspect that was validated using previously reported NADES as well as by developing multiple novel solvents containing ibuprofen. We believe this strategy has the potential to transform the screening process for NADES as well as the pharmaceutical industry, streamlining the use of bioactive compounds as functional components of liquid formulations, rather than simple solutes.