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Ionic liquids (ILs) have been used for carbon dioxide (CO2) capture, however, which have never been used as catalysts to accelerate CO2 capture. The record is broken by a uniquely designed IL, [EMmim][NTf2]. The IL can universally catalyze both CO2 sorption and desorption of all the chemisorption‐based technologies. As demonstrated in monoethanolamine (MEA) based CO2 capture, even with the addition of only 2000 ppm IL catalyst, the rate of CO2 desorption—the key to reducing the overall CO2 capture energy consumption or breaking the bottleneck of the state‐of‐the‐art technologies and Paris Agreement implementation—can be increased by 791% at 85 °C, which makes use of low‐temperature waste heat and avoids secondary pollution during CO2 capture feasible. Furthermore, the catalytic CO2 capture mechanism is experimentally and theoretically revealed. [ABSTRACT FROM AUTHOR]

Covalent organic nanosheets (CONs) are receiving tremendous interest for their potential in versatile applications. However, the synthesis of CONs usually suffers from the use of toxic solvents, low yields and uncontrollable thickness. Here, we report a green, high yield, and scalable strategy to strip two-dimensional imine-linked covalent organic framework (COF) powders in water using bi-functional ionic liquids as both the intercalator and stabilizer under ambient conditions. It is shown that the exfoliation yield reaches up to 66.6%, which is a record value for the delamination of CONs from bulk COF powder. The thickness of CONs is mainly in the range from 0.4 to 2.0 nm and the lateral size is large up to a few hundred nanometers. Importantly, the aqueous IL solutions can be reused and recycled for the exfoliation of CONs. The acid–base and hydrogen bond interactions between CONs and cations of the ILs are found to play critical roles in the delamination and stability of CONs. Furthermore, the CONs without any additives such as metals, photosensitizers, and sacrificial agents have been used as catalysts for photocatalytic CO2 reduction with gaseous water to yield CO in the gas phase under visible-light irradiation. The production rate of CO is 132.2 μmol g−1 h−1, which is twice that by the bulk COF powder, and outperforms most visible-light driven metal-free COFs reported so far. Therefore, the liquid phase stripping approach reported here possesses tremendous potentiality in mass production of CONs for high efficiency photocatalysis of CO2 reduction in the gas phase. [ABSTRACT FROM AUTHOR]

Supercapacitors (SCs) are fascinating energy storage devices due to their delivery of exceptional power density and long cycling stability. Unfortunately, their practical applications are still impeded by relatively inferior energy density, which is proportional to the square of the operating voltage of SCs. Ionic liquid (IL) electrolytes have a wide electrochemical stability window and thus can be used to significantly increase the energy density of SCs. The introduction of redox active species into IL‐based electrolytes effectively contributes to pseudocapacitance. Accordingly, IL‐based redox active electrolytes (IL‐REs) for SCs are springing up rapidly in recent years. This review provides an overall insight into various IL‐REs, including the ILs mixed with other redox active species, the ILs possessing redox active groups themselves, and the IL‐based redox gel polymer electrolytes for SCs. The basic understanding of IL electrolytes and IL‐REs is introduced and discussed as well as the application of the IL‐REs in SCs. Then, the energy storage mechanisms of these IL‐REs are discussed, and finally, current challenges and perspectives are highlighted for future research in this promising field. [ABSTRACT FROM AUTHOR]

Pickering emulsions are an excellent platform for interfacial catalysis. However, developing simple and efficient strategies to achieve product separation and catalyst and emulsifier recovery is still a challenge. Herein, we report the reversible transition between emulsification and demulsification of a light‐responsive Pickering emulsion, triggered by alternating between UV and visible light irradiation. The Pickering emulsion is fabricated from Pd‐supported silica nanoparticles, azobenzene ionic liquid surfactant, n‐octane, and water. This phase behavior is attributed to the adsorption of azobenzene ionic liquid surfactant on the surface of the nanoparticles and the light‐responsive activity of ionic liquid surfactant. The Pickering emulsion can be used as a microreactor that enables catalytic reaction, product separation as well as emulsifier and catalyst recycling. Catalytic hydrogenation of unsaturated hydrocarbons at room temperature and atmospheric pressure has been performed in this system to demonstrate product separation and emulsifier and catalyst re‐use. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) have been widely studied as effective reaction media or catalysts for the conversion of renewable resources to 5-hydroxymethhylfurfural (5-HMF). However, the separation of 5-HMF from ILs remains a significant challenge. Thus, the aim of this work is to develop a useful guideline for the selection and design of greener solvents for efficient separation of 5-HMF from ILs by a simple solvent extraction approach. To this end, 9 kinds of low-toxic and medium boiling point organic solvents and 10 kinds of ILs typically used in biomass conversion have been evaluated for the separation of 5-HMF. The effects of the solvent hydrogen bond acceptor capacity, anion type and cationic structure of the ILs on the separation of 5-HMF from the ILs are systematically investigated and the molecular interactions among 5-HMF, ILs and the solvent contained in the mixtures have been revealed by FTIR and 1H NMR measurements. It has been found that besides a low mutual solubility with ionic liquids, an ideal solvent should have strong hydrogen bond acceptor properties. At the same time, the interactions between the anion and cation of the ILs and the hydrogen bonding interaction of the anion with 5-HMF are also very important for the separation of 5-HMF. A weak interaction of the anion with 5-HMF and a strong interaction between the anion and cation of the ILs all result in the high extraction efficiency. Under the optimized conditions, the extraction efficiency of 5-HMF from the ILs is up to 61.0%, which is a record-breaking value at the current time. This finding provides a useful guide for the selection of greener solvents for the separation of 5-HMF from ILs. [ABSTRACT FROM AUTHOR]

Although significant progress has been made in the synthesis of covalent organic frameworks (COFs) in recent years, the construction of hierarchical pores in such materials remains a great challenge. Herein, we report a facile synthesis of hierarchically porous COFs (HP-COFs) under mild conditions in ionic liquids 1-alkyl-3-methylimidazolium tetrafluoroborates ([Cnmim][BF4], n = 4, 6, 10). It has been found that apart from the inherent micropores, a large mesoporous structure has been produced in the COFs in which the size of pores can be simply tuned by adjusting the alkyl chain length of the ionic liquids. These mesopores have been confirmed by N2 sorption and electron microscopy techniques. Importantly, this approach is applicable for the preparation of various HP-COFs, such as imine and hydrazone based COFs, which are quite difficult to acquire through traditional methods. In addition, these HP-COFs show highly effective catalytic performance for C–C bond formation, especially for large size molecule based C–C coupling reactions in comparison with uni-pore COFs. [ABSTRACT FROM AUTHOR]

The great challenges of modern industry and the environment make it important to develop sustainable energy resources with low cost. In this work, a cleaner enzymatic procedure for biodiesel production was developed through the utilization of a biocompatible and hydrophilic ionic liquid [Choline][H2PO4]. This ionic liquid can be synthesized from cheap raw materials through simple neutralization procedures, and it has been proved to be well biocompatible. The utilization of this ionic liquid in Novozym 435 catalyzed biodiesel production makes the reaction and work-up procedures very simple, because its hydrophilicity can lead to the implementation of a pseudo homogeneous reaction and then heterogeneous separation. Various oil resources such as triolein, sunflower oil and castor oil can all be converted to biodiesels with high yields. After the completion of reaction, both the ionic liquid and Novozym 435 can be recycled and reutilized for at least five cycles without a significant activity decrease. In addition, this reaction system can be conveniently scaled up to the multi-gram level with high efficiency and feasible separation. Overall, the above mentioned benefits make this ionic liquid based enzymatic system cleaner for the production of biodiesel and promising for further industrial applications. [ABSTRACT FROM AUTHOR]

Cholinium 2,4-dicholophenolate was found to be an excellent reaction medium and catalyst for the fixation of CO 2 to structure diversely quinazoline-2,4-(1H,3H)diones under mild reaction conditions. This reaction system is suitable for the modification of drug-like biomolecules and the triple activation effect from one ionic liquid is believed to be the main reason for the excellent performance of ionic liquid. • Cholinium based ionic liquid is efficient in promoting CO 2 conversion under 1 atmosphere. • Triple activation effect from one ionic liquid towards three reaction centers. • The reaction system is very simple, no solvents or additives are needed. • The work-up procedure is very simple and ionic liquid is reusable. • The utilization of CO 2 in drug-like molecules may open new field of CO 2 utilization. The chemical fixation of CO 2 is intriguing to eliminate its impact on climate, but harsh reaction conditions are often involved. Herein, we report a new ionic liquid cholinium 2,4-dichlorophenolate which can efficiently promote the conversion of CO 2 to quinazoline-2,4(1H,3H)-diones at 1atm CO 2 and near room temperature without any other additives. This mild reaction system is friendly to biomolecules such as glycoside and nucleoside with sensitive functional groups, leading to the successful CO 2 fixation in biomolecules modification. In addition, this reaction system is easy to conduct, and the target compounds can be separated by simple precipitation after the reaction. The reaction mechanism studies reveal that the ionic liquid have triple activation effects toward all of the three reaction centers of the target reaction. The triple activation in one ionic liquid gives important clues for the designation of ionic liquids according to a specific reaction. [ABSTRACT FROM AUTHOR]

Numerous applications of ionic liquids (ILs) are often accompanied by the generation of aqueous wastes. Due to the high toxicity and poor biodegradability of ILs, effective chemical treatment is of great importance for their removal from aqueous solution. In this work, an ultrasound-assisted zero-valent iron/activated carbon (US-ZVI/AC) micro-electrolysis technique was used to degrade residual functionalized ILs, 1-butyl-3-methyl benzimidazolium bromide ([BMBIM]Br) and 1-allyl-3-methylimidazolium chloride ([AMIM]Cl) in aqueous solution, and the degradation degree, degradation kinetics and possible degradation pathways were investigated. It was shown that the degradation of these functionalized ILs was highly efficient in the US-ZVI/AC system, and the degradation degree was as high as 96.1% and 92.9% in 110 min for [BMBIM]Br and [AMIM]Cl, respectively. The degradation of [BMBIM]Br could be described by the second-order kinetics model, and [BMBIM]+ was decomposed in two ways: (i) sequential cleavage of N-alkyl side chain of the cation produced three intermediates; (ii) the 2-positioned H atoms of the benzimidazolium ring were first oxidized, and then the imidazolium ring was opened. The degradation of [AMIM]Cl followed the first-order kinetics rule, and the 2,4,5-positioned H atoms of the imidazolium ring were oxidized to induce ring opening. In addition, the removal of total organic carbon was found to be >87%, which indicates that most of the ILs was mineralized in the degradation process. These results suggest that ultrasound-assisted ZVI/AC micro-electrolysis is highly effective for the removal of residual functionalized ILs from aqueous environment. [ABSTRACT FROM AUTHOR]

Development of new chemical processes with simplified reaction systems and work-up procedures is a challenging task. Although ionic liquids are a class of potential multifunctional compounds to simplify traditional chemical processes, their rational design is difficult due to complex interactions. In this work, a proof-of-concept strategy has been proposed to achieve an integration of high-throughput preparation of ionic liquids and in situ screening of their reaction-promoting performance in 96-well plates. The integrated approach then enables a facile identification of optimal ionic liquids from a 400-ionic liquid candidate pool to act as the solvent, the catalyst and the separating assistant, simultaneously, for carbonyl-azide cycloaddition reactions. Merits of the ionic liquids-based processes have been demonstrated not only in the convenient and efficient synthesis of 1,2,3-triazolyl compounds but also in the discovery of a new reaction for the chemical post-modification of free peptides. [ABSTRACT FROM AUTHOR]

The water content is crucial to the preparation of [P4442][Suc] and its capture of CO2. The use of a large amount of water in the preparation of this ionic liquid results in the significant formation of the byproduct succinamate anions and difficulties in water removal, which strongly reduces the capacity of CO2 absorption through a bicarbonate mechanism. By contrast, the addition of a small amount of water maintains a high absorption capacity through cooperation. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Among the studied imide-based ILs, [P 4442 ][Cy-Suc] has the lowest density and the highest viscosity. • CO 2 capture can be efficiently tuned by substitute on the imide-based anions of the ILs. • The capture capacity of CO 2 by [P 4442 ][Cy-Suc] is as high as 2.21 mol of CO 2 per mole of the IL. • The absorption process by imide-based ILs was highly reversible and energy-saving. Abstract Minimizing the release of CO 2 into the atmosphere is highly important due to the CO 2 concentration dependence of climate change. In this work, highly efficient capture of CO 2 is investigated through tuning ionic liquids (ILs) with imide-based anions. It is found that a superior high CO 2 capacity (2.21 mol mol−1) be achieved by the imide-based IL with 1,2-cyclohexanedicarboximide anion at 20 °C and 1.0 bar through a combination of chemical and physical absorption. Quantum chemical calculations and spectroscopic analysis suggests that the significant increase in the CO 2 capacity is due to the enhanced cooperative interactions between CO 2 and three active sites in the anion with electron-donating group. Furthermore, the adsorbed CO 2 can be readily stripped from the CO 2 -saturated IL through slightly heating or bubbling N 2 , and the IL may be recycled without loss of efficiency. [ABSTRACT FROM AUTHOR]

In this work, a simple, rapid and economic one-pot strategy is developed for the synthesis of 3D nanoporous gold (NPG) in aqueous solution with the assistance of a functionalized ionic liquid, 1-hydroxyethyl-3-methylimidazolium chloride ([HEmim]Cl), at room temperature. It is shown that 3D NPG is constructed from twisted and interconnected Au nanochains with diameters of approximately 40 nm. This material has a high specific surface area of 22.77 m2 g−1 and various porous structures, including macropores, mesopores and micropores. Yet, there are lots of crystal defects, such as a twin boundary, edge atoms and amorphous regions. It is demonstrated that [HEmim]Cl plays an important role in directing the growth and assembly of 3D NPG, and the ionic liquid concentration, the amount of reductant and the reaction temperature also have influences on the morphology and structure of NPG to a certain extent. Based on control experiments, a possible growth mechanism is illustrated for the formation of 3D NPG. In addition, the as-prepared 3D NPG exhibits superior catalytic activities for both the reduction of p-nitrophenol and the degradation of methylene blue in water, which can be completed in 14 min and 8 min, respectively, at 25 °C. [ABSTRACT FROM AUTHOR]

It is a challenge to develop microemulsions which can serve as nanoreactors for the synthesis of nanoparticles and chemical reactions at high temperature. In this work, a class of novel high temperature microemulsions consisting solely of ionic liquids have been designed and prepared for the first time. It is found that nanoscale droplets formed in the ionic liquid microemulsions can be maintained up to 200 °C, and the size distribution of the droplets can be easily tuned by selection of the ionic liquids and varying compositions of the systems. By using such microemulsions as nanoreactors, porous metals such as Pt have been prepared at 180 °C without using any purposely added reductant. [ABSTRACT FROM AUTHOR]

Recently, efficient chemical conversion of CO 2 into high value chemicals at room temperature and atmospheric pressure without using noble metal catalysts remains a great challenge. In this work, we find that the carboxylative cyclization of propargylic alcohols with CO 2 can proceed at 60 °C and ambient pressure by using a combination of CuI and an ionic liquid (IL) 1,8-diazabicyclo-[5.4.0]-7-undecenium trifluoroethanol ([DBUH][TFE]) as catalyst. By simple extraction after the reactions, a series of desired products have been obtained in good to excellent yields with this highly efficient catalyst system. Spectroscopic investigations and DFT calculations demonstrate that such a high efficiency originates from remarkable synergistic catalysis between Cu(I) and the IL on substrates. In addition, it is worth noting that this catalyst system also works well for the carboxylative cyclization of propargylic amines even at ambient temperature and pressure, with the highest turnover number among the reported base metals catalytic systems. [ABSTRACT FROM AUTHOR]

A new strategy involving the computer-assisted design of substituted imidazolate-based ionic liquids (ILs) through tuning the absorption enthalpy as well as the basicity of the ILs to improve SO2 capture, CO2 capture, and SO2/CO2 selectivity was explored. The best substituted imidazolate-based ILs as absorbents for different applications were first predicted. During absorption, high SO2 capacities up to ≈5.3 and 2.4 mol [ABSTRACT FROM AUTHOR]

A novel strategy based on the concept of preorganization and cooperation has been designed for a superior capacity to capture low-concentration CO2 by imide-based ionic liquids. By using this strategy, for the first time, an extremely high gravimetric CO2 capacity of up to 22 wt % (1.65 mol mol−1) and excellent reversibility (16 cycles) have been achieved from 10 vol. % of CO2 in N2 when using an ionic liquid having a preorganized anion. Through a combination of quantum-chemical calculations and spectroscopic investigations, it is suggested that cooperative interactions between CO2 and multiple active sites in the preorganized anion are the driving force for the superior CO2 capacity and excellent reversibility. [ABSTRACT FROM AUTHOR]

Photoelectrochemical (PEC) reduction of carbon dioxide (CO2) is a potential method for production of fuels and chemicals from a C1 feedstock accumulated in the atmosphere. However, the low solubility of CO2 in water, and complicated processes associated with capture and conversion, render CO2 conversion inefficient. A new concept is proposed in which a PEC system is used to capture and convert CO2 into formic acid. The process is assisted by an ionic liquid (1-aminopropyl-3-methylimidazolium bromide) aqueous solution, which functions as an absorbent and electrolyte at ambient temperature and pressure. Within this PEC reduction strategy, the ionic liquid plays a critical role in promoting the conversion of CO2 to formic acid and suppressing the reduction of H2O to H2. At an applied voltage of 1.7 V, the Faradaic efficiency for formic acid production is as high as 94.1 % and the electro-to-chemical efficiency is 86.2 %. [ABSTRACT FROM AUTHOR]

Rational design of ingenious strategies to build hierarchical architectures of nanomaterials is highly desirable and technically important due to their excellent properties and widespread application in varied fields. Here, we report a facile one-pot approach for the solvothermal synthesis of freestanding CuS nanowalls with the assistance of a common ionic liquid, 1-decyl-3-methylimidazolium bromide ([C10mim]Br). In the presence of [C10mim]Br, intriguing CuS nanowalls have been fully constructed from the as-generated CuS thin nanosheets at the liquid–liquid interface of chloroform and water. An outstanding feature is that no hard template is utilized to support and/or assist the growth of CuS nanowalls. The as-prepared CuS nanowalls have been characterized and analyzed systematically and a series of factors affecting the morphology have been investigated. It is found that the alkyl chain length, anionic nature and heterocyclic structure of ionic liquids play an important role in directing the formation of freestanding CuS nanowalls. A possible growth mechanism for the formation of CuS nanowalls is presented based on control experiments. In addition, the as-synthesized CuS nanowalls demonstrate prominent catalytic activity for the thermal decomposition of ammonium perchlorate (AP). [ABSTRACT FROM AUTHOR]

The efficient conversion of CO2 into value-added chemicals under metal-free conditions is of significant importance from the viewpoint of sustainable chemistry. In this work, ionic liquids (ILs) with different properties were used to promote the reaction between CO2 and propargylic alcohol for the synthesis of α-alkylidene cyclic carbonates. The protic IL 1,8-diazabicyclo-[5.4.0]-7-undecenium 2-methylimidazolide ([DBUH][MIm]) was prepared by simple neutralization of the superbase with a weak proton donor and could efficiently promote the reactions in high yields. After the reactions, the IL was separated from the reaction mixtures by simply adding water, and then reused after drying without an observable decrease in the catalytic activity and selectivity. NMR spectroscopy and detailed density functional theory analysis were used to propose a reaction mechanism. Both the cation and anion of the IL played a key synergistic role in promoting the reaction. These findings may be useful for the rational design of novel metal-free and recyclable routes for the reaction between CO2 and propargylic alcohols. [ABSTRACT FROM AUTHOR]

In this work, a hydroxyl functionalized Lewis acidic ionic liquid on silica is found to be an efficient heterogeneous catalyst for the C-3 Friedel-Crafts benzylation of indoles with different benzyl alcohols as benzylation agents under mild conditions. This catalytic system benefits from simple operation, work-up and reutilization procedures, wide substrate tolerance, low cost, high catalytic activity and excellent chemo-selectivity. The hybrid combination of hydroxyl functionalized ionic liquid and silica through the formation of hydrogen bond endows this catalyst with high stability in the Friedel-Crafts reaction system, and the catalyst could be easily recycled and reutilized. Graphical Abstract: A hydroxyl functionalized Lewis acid ionic liquid supported on silica was found to be an efficient catalyst for the C-3 Friedel-Crafts benzylation reaction of iodole with alcohols. This catalyst benefits from low cost, feasible preparation and reutilization, high catalytic activity and selectivity, and the operation and work-up procedures are very simple. [ABSTRACT FROM AUTHOR]

Correction for 'An azobenzene-modified redox-active ionic liquid electrolyte for supercapacitors' by Yuhua Zhao et al., Chem. Commun., 2022, https://doi.org/10.1039/d2cc04081f. [ABSTRACT FROM AUTHOR]

Development of novel technologies for the efficient and reversible capture of CO2 is highly desired. In the last decade, CO2 capture using ionic liquids has attracted intensive attention from both academia and industry, and has been recognized as a very promising technology. Recently, a new approach has been developed for highly efficient capture of CO2 by site-containing ionic liquids through chemical interaction. This perspective review focuses on the recent advances in the chemical absorption of CO2 using site-containing ionic liquids, such as amino-based ionic liquids, azolate ionic liquids, phenolate ionic liquids, dual-functionalized ionic liquids, pyridine-containing ionic liquids and so on. Other site-containing liquid absorbents such as amine-based solutions, switchable solvents, and functionalized ionic liquid–amine blends are also investigated. Strategies have been discussed for how to activate the existent reactive sites and develop novel reactive sites by physical and chemical methods to enhance CO2 absorption capacity and reduce absorption enthalpy. The carbon capture mechanisms of these site-containing liquid absorbents are also presented. Particular attention has been paid to the latest progress in CO2 capture in multiple-site interactions by amino-free anion-functionalized ionic liquids. In the last section, future directions and prospects for carbon capture by site-containing ionic liquids are outlined. [ABSTRACT FROM AUTHOR]

The separation and recycling of catalyst and cocatalyst from the products and solvents are of critical importance. In this work, a class of functionalized ionic liquids (ILs) were designed and synthesized, and by tuning the hydrophilicity and hydrophobicity of cation and anion, respectively, these ILs could reversibly transfer between water and organics triggered upon undergoing a temperature change. From a combination of multiple spectroscopic techniques, it was shown that the driving force behind the transfer was originated from a change in conformation of the PEG chain of the IL upon temperature variation. By utilizing the novel property of this class of ILs, a highly efficient and controllable CuI-catalyzed cycloaddition reaction was achieved wherein the IL was used to entrain, activate, and recycle the catalyst, as well as to control the reaction. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) have many potential applications in the chemical industry. In order to understand ILs, their molecular details have been extensively investigated. Intuitively, electrostatic forces are solely important in ILs. However, experiments and calculations have provided strong evidence for the existence of H-bonds in ILs and their roles in the properties and applications of ILs. As a structure-directing force, H-bonds are responsible for ionic pairing, stacking and self-assembling. Their geometric structure, interaction energy and electronic configuration in the ion-pairs of imidazolium-based ILs and protic ionic liquids (PILs) show a great number of differences compared to conventional H-bonds. In particular, their cooperation with electrostatic, dispersion and π interactions embodies the physical nature of H-bonds in ILs, which anomalously influences their properties, leading to a decrease in their melting points and viscosities and thus fluidizing them. Using ILs as catalysts and solvents, many reactions can be activated by the presence of H-bonds, which reduce the reaction barriers and stabilize the transition states. In the dissolution of lignocellulosic biomass by ILs, H-bonds exhibit a most important role in disrupting the H-bonding network of cellulose and controlling microscopic ordering into domains. In this article, a critical review is presented regarding the structural features of H-bonds in ILs and PILs, the correlation between H-bonds and the properties of ILs, and the roles of H-bonds in typical reactions. [ABSTRACT FROM AUTHOR]

The present study aimed to determine the cytotoxicity of 1-methyl-3-octylimidazolium bromide ([C 8 mim]Br) on the human hepatocellular carcinoma (HepG2) cells in order to elucidate the biochemical and molecular mechanism of [C 8 mim]Br-cytotoxicity. For this purpose, cell viability, oxidative stress, apoptosis, caspase activity, and apoptosis-related gene expression in HepG2 cells following [C 8 mim]Br-exposure were evaluated. The results showed that viability of HepG2 cells was decreased by [C 8 mim]Br-exposure in a concentration-dependent pattern. Moreover, biochemical assays reveal that [C 8 mim]Br-exposure can induce apoptosis, cause overproduction of reactive oxygen species (ROS), inhibit superoxide dismutase and catalase, reduce glutathione content, and increase the cellular malondialdehyde level of HepG2 cells. The transcriptions of p53 and bax were markedly up-regulated while bcl-2 was significantly down-regulated in HepG2 cells after [C 8 mim]Br-exposure, suggesting that p53 and bcl-2 family may be involved in the cytotoxicity and apoptosis of HepG2 cells caused by [C 8 mim]Br. In addition, we also found that caspase-3, caspase-8, and caspase-9 were significantly activated in HepG2 cells following [C 8 mim]Br-exposure. Our results suggest that ROS may be a key early signal of [C 8 mim]Br-induced apoptosis and caspases play a key role in the initiation and execution of apoptosis of HepG2 cells. [ABSTRACT FROM AUTHOR]

Increasing the glucose loading in the 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) ionic liquid containing a dissolved CrCl3 catalyst system led to excessive formation of humins and a serious decrease in the 5-hydroxymethylfurfural (5-HMF) yield. A biphasic system containing glycol dimethyl ether (GDE) as the extraction phase, and [BMIM]Cl/CrCl3/glucose in combination with a partitioned amount of GDE and an appropriate amount of water as the reaction phase was found to be highly efficient for the reaction; CrCl3 catalyzed the formation of 5-HMF in 64.5 mol% yield from a very high glucose concentration (80 wt% with respect to the ionic liquid) at 108 °C. This 5-HMF yield in the [BMIM]Cl–GDE–H2O ternary biphasic system nearly doubled that obtained in the single [BMIM]Cl/CrCl3/glucose reaction phase. Importantly, the GDE phase contained about 56% of the generated 5-HMF without detectable contamination by the ionic liquid or carbohydrates. GDE served multiple functions: as a hydrogen-bond acceptor, it exhibited excellent extraction performance for 5-HMF; due to its low boiling point and suitable solubility saturation point in the ionic liquid, a sustained GDE bubbling phenomenon in the ionic liquid phase was observed that promoted the rate of inter-phase mass-transfer of 5-HMF in reactions; and GDE mediated the [BMIM]Cl phase to a reduced viscosity. In addition, an appropriate amount of water in the ternary system promoted the extraction efficiency of 5-HMF and also lowered the viscosity of [BMIM]Cl/glucose. The ionic liquid–organics–water ternary biphasic system has been demonstrated for high 5-HMF productivity and separation efficiency. [ABSTRACT FROM AUTHOR]

In this paper, a series of ionic liquids (ILs) contains cholinium as cations were prepared. These ILs were used as extractants to separate some model drug molecules. The partition coefficients of these drug molecules between ILs and aqueous solutions were determined. Furthermore, the influence of different extraction parameters was investigated: volume ratio, equilibrium time, pH values, temperature, and ILs structure. It is shown that these ILs are highly effective materials for the extraction of drug molecules. The results imply that these ILs may have potential in drug extraction or separation as a new type of media. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) with a reversible hydrophobic-hydrophilic transition were developed, and they exhibited unique phase behavior with H2O: monophase in the presence of CO2, but biphase upon removal of CO2 at room temperature and atmospheric pressure. Thus, coupling of reaction, separation, and recovery steps in sustainable chemical processes could be realized by a reversible liquid-liquid phase transition of such IL-H2O mixtures. Spectroscopic investigations and DFT calculations showed that the mechanism behind hydrophobic-hydrophilic transition involved reversible reaction of CO2 with anion of the ILs and formation of hydrophilic ammonium salts. These unique IL-H2O systems were successfully utilized for facile one-step synthesis of Au porous films by bubbling CO2 under ambient conditions. The Au porous films and the ILs were then separated simultaneously from aqueous solutions by bubbling N2, and recovered ILs could be directly reused in the next process. [ABSTRACT FROM AUTHOR]

A new approach has been developed to improve SO2 sorption by cyano-containing ionic liquids (ILs) through tuning the basicity of ILs and cyano-sulfur interaction. Several kinds of cyano-containing ILs with different basicity were designed, prepared, and used for SO2 capture. The interaction between these cyano-containing ILs and SO2 was investigated by FTIR and NMR methods. Spectroscopic investigations and quantum chemical calculations showed that dramatic effects on SO2 capacity originate from the basicity of the ILs and enhanced cyano-sulfur interaction. Furthermore, the captured SO2 was easy to release by heating or bubbling N2 through the ILs. This efficient and reversible process, achieved by tuning the basicity of ILs, is an excellent alternative to current technologies for SO2 capture. [ABSTRACT FROM AUTHOR]

The adsorption of CO 2 , N 2 , O 2 and H 2 in 1-buty-3-methylimidazolium heptafluorobutyrate, [C 4 mim][CF 3 CF 2 CF 2 COO], was theoretically studied under isolated conditions. It was shown that in gas–[CF 3 CF 2 CF 2 COO] − complexes, the gas molecules are directed toward oxygen atoms of the [CF 3 CF 2 CF 2 COO] − anion, while in gas–[C 4 mim] + complexes the gas molecules interact with the imidazolium ring via hydrogen bond formation with C2 H. The relative position of the anion and the cation in the ion pair is almost unaffected by the presence of the gas molecules. In order to have a better understanding on the difference in gas solubility, the interaction energies between the gas molecules and the anion, cation and the whole ion pair were calculated. It was found that for gas–[cation] and gas–[ion pair] systems, the order based on the interaction energies estimated at PBE/aug-cc-pVDZ level is qualitatively in agreement with that based on the experimental data, while the same is not true for the gas–[anion] systems. [ABSTRACT FROM AUTHOR]

Abstract: Many applications of ionic liquids (ILs) are closely related with their microstructure in mixtures. For example, morphology and pore size of the MCM-41 prepared in aqueous ILs are greatly dependent on the aggregation behavior of the ILs in water. Therefore, the study on the microstructure of ILs in aqueous solutions is of great importance. In this work, 1H NMR, dynamic light scattering and attenuated total reflection infrared spectroscopy have been used to investigate the temperature effect on the structures of aqueous 1-butyl-3-methylimidazolium tetrafluoroborate ([C4mim][BF4]) solutions. It was shown that the size of the IL aggregates becomes larger with decreasing temperature. When the system temperature is below the upper critical solution temperature (UCST) of the binary mixture at about 4°C, the aggregate size of the IL is larger than 1000nm. Additionally, the two-dimensional IR results reveal that at low IL concentrations, H2O can interact with [BF4]− prior to the C H groups of the imidazolium ring, whereas cation and anion of the IL tend to form aggregate at high IL concentrations. With the decrease of temperature, the interactions between cation and anion of the IL become stronger, but those between the IL and water become weaker, thereby resulting in the growth of the aggregate of cation with anion of the IL. This result may give a reasonable explanation for the origin of the UCST behavior of aqueous [C4mim][BF4] solution. [Copyright &y& Elsevier]

Highlights: [•] Glycine ILs [N5555][Gly], [P4444][Gly], [N4444][Gly] and [N2222][Gly] were prepared. [•] Partition coefficients of DNP-amino acids and cytochrome-c were determined in glycine ILs/K2HPO4 ATPSs. [•] Gibbs energies of transfer of methylene between the two phases were calculated. [•] Hydrophobic interaction is the main driving force for the efficient partition of the protein in the IL-rich phases. [ABSTRACT FROM AUTHOR]

In many practical processes, separation of aliphatic amines from aromatic amines in water is imperative to obtain the desired products. In this work, a novel strategy was proposed for selective separation of aliphatic amines from aromatic amines with CO2 switchable ionic liquids (ILs) aqueous two-phase systems (ATPSs). It was shown that upon introduction of CO2 into an aqueous solution containing the IL, aliphatic amine and aromatic amine at 25 °C and atmospheric pressure, an ATPS could be formed with an IL-rich top phase and an ammonium-salt-rich bottom phase. Under these circumstances, the aromatic amine was largely partitioned in the IL-rich phase, while the aliphatic amine was transformed into the ammonium salt by the reaction with CO2. Thus the aliphatic amine was well separated from the aromatic amine in aqueous solution. The distribution ratios of aromatic amines between the two phases were found to increase with increasing hydrophobicity of ILs and aromatic amines, pKa values of aliphatic amines and tie-line length of the systems. Moreover, aliphatic amines retained in the ammonium-salt-rich phases were regenerated by bubbling N2 under heating, while aromatic amines in the IL-rich phases were removed by simple steam distillation. The recovery efficiency for aliphatic amines was as high as 99.0%. The regenerated ILs could then be reused in the next separation process, and no decrease in the distribution ratios of aromatic amines was observed after six cycles. [ABSTRACT FROM AUTHOR]

ABSTRACT This study aims to evaluate the cytotoxicity and responses of the cellular antioxidant system of 1-octyl-3-methylimidazolium chloride ([C8mim][Cl]) on human hepatocarcinoma QGY-7701 cells. The results show that [C8mim][Cl] can inhibit QGY-7701 cell growth and decrease their viabilities in a dose-dependent manner. The results also reveal that [C8mim][Cl] exposure can induce apoptosis in the [C8mim][Cl]-treated QGY-7701 cells. In addition, the results of biochemical assays show that [C8mim][Cl] exposure causes overproduction of reactive oxygen species (ROS), inhibits superoxide dismutase (SOD) and catalase (CAT) activities, decreases reduced glutathione (GSH) content, and increases the cellular malondialdehyde (MDA) level. These results suggest that ROS-mediated oxidative stress may be responsible for the apoptosis induced by [C8mim][Cl] in QGY-7701 cells. © 2013 Wiley Periodicals, Inc. J BiochemMol Toxicol 27:330-336, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/jbt.21495 [ABSTRACT FROM AUTHOR]

A series of choline-based ionic liquids (CIL) have been synthesized in this work. The results suggested that both the cations and the anions have significant influences on their properties such as thermostabilities, acidities and their performances for the synthesis of 3,4-dihydro-2(H)-pyrimidinones. The optimized catalytic system based on the CIL [DMEA][HSO] for the Biginelli reactions benefits from the wide substrates tolerance, benign reaction conditions, easy work-up procedures, and the feasible reusability of the ionic liquid. Graphical Abstract: The thermostabilities, acidities, and the catalytic activities for the Biginelli reactions are all follows the sequence of [DMEA][HSO] > [Choline] [HSO] > [DMEA][HPO] > [Choline] [HPO][Figure not available: see fulltext.]. [ABSTRACT FROM AUTHOR]

Ionic liquids have gained more attention due to their excellent properties in many different scientific fields. However, previous researches indicated that ionic liquids have adverse effects on organisms. The objective of this study was to evaluate the effects of 1-octyl-3-methylimidazolium bromide ([Cmim]Br) on the aquatic plant duckweed ( Lemna minor) by exposure of the plant to 0.25 to 2 mg L of [Cmim]Br for 28 days. Exposure to [Cmim]Br significantly decreased the photosynthetic pigment contents at 21 and 28 days. The activities of superoxide dismutase and catalase and the total antioxidant capacity level increased at 7 days of exposure and decreased at the termination of exposure. In contrast, the HO content and peroxidase activity in all treatments increased during the period of exposure. Furthermore, marked increase of malondialdehyde content occurred in duckweed after 21 to 28 days of exposure. In addition, reactive oxygen species (ROS) scavenger dimethyl thiourea prevents duckweed from oxidative damage caused by [Cmim]Br. These results suggest that ROS might be involved in the mechanism of ionic liquid-induced toxicity in L. minor. [ABSTRACT FROM AUTHOR]

In this work, densities and viscosities for the binary mixtures of 1-octyl-3-methylimidazolium tetrafluoroborate, [Cmim][BF], with butanone, methyl acetate, ethyl acetate, propyl acetate and butyl acetate have been determined at 298.15 K. These data were used to calculate the excess molar volumes $$ V_{m}^{\text{E}} $$ and the viscosity deviations (ln η) for the mixtures. It is shown that values of $$ V_{m}^{\text{E}} $$ are negative, while those of (ln η) are positive in the whole concentration range. The $$ V_{m}^{\text{E}} $$ values show their minimum at the composition of x ≈ 0.3, and the (ln η) values exhibit a maximum at the same mole fraction. For the binary systems, the absolute values of $$ V_{m}^{\text{E}} $$ decrease in the order: butanone > methyl acetate > ethyl acetate > propyl acetate > butyl acetate, whereas those of (ln η) decrease in the order: methyl acetate > ethyl acetate > propyl acetate > butyl acetate > butanone. The results are discussed in terms of the ion-dipole interactions between cations of the ionic liquid and the organic molecules and hydrogen bonding interactions between anions of the ionic liquid and the organic compounds. [ABSTRACT FROM AUTHOR]

Recovery is a very important factor for the industrial application of ionic liquids (ILs). In this work, a novel method is presented for the recovery of ILs by using carbon dioxide (CO2)-induced formation of aqueous two-phase systems (ATPSs). It was found that, in the presence of amines, introduction of CO2 into aqueous IL solutions leads to the formation of ATPSs at 25 °C and atmospheric pressure, in which the upper phase is ammonium-salt-rich and the lower phase is IL-rich. Thus, the ILs in aqueous solutions can be significantly enriched, and the amines can be regenerated by heating and bubbling Ar or N2 in the salt-rich phase. To better understand the recovery of ILs, the phase diagrams of the ATPSs were measured at 25 °C, and the effects of the molecular structure of the ILs and the amines and temperature of the systems on the recovery efficiency of the ILs were investigated. It was shown that the single-step recovery efficiency of the ILs could be as high as 99 % in the presence of primary or secondary amines. Therefore, this new method could potentially be sustainable, efficient, and attractive to industry. [ABSTRACT FROM AUTHOR]

Ionic liquids (ILs) have numerous applications in industrial processes as a benign alternative to conventional volatile organic solvents. However, many of them are toxic to organisms and are poorly biodegradable. In this work, a series of environmentally friendly cholinium ILs have been designed and synthesized. It was found that these ILs could form aqueous two-phase systems (ATPSs) with polypropylene glycol 400 (PPG400) which is thermo-sensitive, non-toxic and biodegradable. In order to understand the phase formation processes and possible application of these ATPSs for extraction/separation of proteins, the binodal curves and tie lines of these ATPSs were measured at 25 °C, and the effects of anionic structure of the ionic liquids, nature of the proteins and difference in the concentration of top- and bottom-phases on the partitioning behavior of some typical proteins were investigated systematically. It was shown that bovine serum albumin (BSA), trypsin, papain and lysozyme could be enriched effectively into the ionic liquid-rich phase of the ATPSs, and single-step extraction efficiency could be as high as 86.4–99.9% under the optimized conditions. Furthermore, enzyme activity of the native trypsin in water and in aqueous ionic liquid solutions was determined by using N-a-benzoyl-l-arginine ethyl ester as a substrate, and activity increases to about 127% was observed after 13 months storage. In addition, PPG400 has been recovered simply by heating and reused in the next extraction processes. This avoids the non-sustainable issue of highly salty water produced in the application of the polyethylene glycol (PEG) + salt and ionic liquid + salt ATPSs. [ABSTRACT FROM AUTHOR]

Densities for solutions of [Cnmim]Br(n= 4, 8, 10, 12) ionic liquids (ILs) in dimethylsulfoxide (DMSO) have been determined as a function of ionic liquidconcentration at the temperature T= (293.15, 298.15,303.15, 308.15, and 313.5) K and atmospheric pressure. The apparentmolar volumes, apparent molar volumes at infinite dilution, and limitingapparent molar expansivities of the ILs have been obtained from theexperimental density data. These data were used to understand theeffect of the alkyl chain length of the ILs and experimental temperatureon the IL–DMSO interactions occurring in the studied solutions.It was shown that the apparent molar volumes at infinite dilutionincreased with increasing alkyl chain length of the ILs and temperatureof the systems. Furthermore, the values of the limiting apparent molarexpansibilities were found to be positive and decreasewith increasing temperature. [ABSTRACT FROM AUTHOR]

Understanding the structure of ionic liquids under external electric field (EEF) is very important for their applications in many fields, such as cells, electrowetting and electrospray. An all-atom molecular dynamic simulation was performed under EEF for [C2MIM][BF4] in order to explore the structure and properties of ionic liquids. It is found that EEF can change the distribution from disorder to order and influence the shape of cations. We investigated the hydrogen bond further and found that the hydrogen bond network can be destroyed when EEF reaches a critical value (1.14 V/Å). Due to the order's arrangement of ions under EEF, it is found that the diffusion coefficient of solute in the direction of electric field is greatly enhanced. However, the ions are diffused slowly in the perpendicular direction to the electric field when EEF exceeds the critical value. [ABSTRACT FROM PUBLISHER]

Carboxylate-anion-based imidazolium ionic liquids (ILs)are powerfulsolvents for cellulose and lignin. However, little is known abouttheir fundamental physicochemical properties. In this work, 1-butyl-3-methylimidazoliumcarboxylate ILs 1-butyl-3-methylimidazolium formate ([C4mim][HCOO]), acetate ([C4mim][CH3COO]), propionate([C4mim][CH3CH2COO]), and butyrate([C4mim][CH3(CH2)2COO]),in which the alkyl chain length in the anions is being varied in contrastto the more usual studies where alkyl chain length in the cationsis varied, have been synthesized and their densities and surface tensionshave been determined experimentally at different temperatures. Byusing these data, the molar volume, isobaric expansivity, standardentropy, lattice energy, surface excess entropy, vaporization enthalpy,and Hildebrand solubility parameter have been estimated for theseILs. From the analysis of structure–property relationship,the effect of alkyl chain length in the anions on these physicochemicalproperties of the ILs has been assessed and the dissolution of celluloseand lignin in these ILs has been discussed. Such knowledge is expectedto be useful for understanding the nature of this class of solventfor the dissolution of biomacromolecules. [ABSTRACT FROM AUTHOR]

The recovery of wastewater proteins is gaining more attention in environmental protection. In the present work, phase diagram of the [Cnmim]X (n = 4, 6, 8; X = Cl and Br) + K2HPO4 aqueous two-phase systems have been determined, and the aqueous two-phase systems have been used to remove bovine serum albumin (BSA), lysozyme, and hemoglobin from the simulated wastewater. The influence of pH value, the composition of the aqueous two-phase systems, and the temperature of the systems on the partitioning of the proteins has been studied. It has been found that 76–100% of the proteins could be extracted into the ionic liquid-rich phase in a single step partition. The partition coefficients of lysozyme slightly increases but those of BSA and hemoglobin decrease with increasing tie line length (TLL). The higher extraction efficiency of the proteins is achieved at the pH value close to their isoelectric point and under higher temperatures. The results indicate that the IL-based aqueous two-phase systems have the potential for the separation of wastewater proteins. [ABSTRACT FROM AUTHOR]

Abstract: Compared with the conventional ionic liquids, amino acid ionic liquids are more biodegradable and biocompatible, and can enhance stability of biomaterials. In this work, amino acid ionic liquids 1-butyl-3-methylimidazolium l-serine ([C4mim][Ser]), 1-butyl-3-methylimidazolium glycine ([C4mim][Gly]), 1-butyl-3-methylimidazolium l-alanine ([C4mim][Ala]) and 1-butyl-3-methylimidazolium l-leucine ([C4mim][Leu]) have been synthesized. These ionic liquids are found to form aqueous two-phase systems (ATPSs) by the salted-out of K3PO4 in aqueous solutions. Phase diagram of the ATPSs and the Gibbs energies of transfer of methylene group from the bottom salt-rich phase to the top ionic liquid-rich phase have been determined at 298.15K and pH 14, and the effect of anionic structure of the ionic liquids on phase formation of the ATPSs and the relative hydrophobicity between the top and the bottom phases are then examined. In order to understand the effect of relative hydrophobicity of the phases in equilibrium in the ATPSs on the extraction/separation capability of biomolecules, the partition coefficients of cytochrome-c (as a model biomolecule) in the ATPSs are measured by spectrophotometry. It is suggested that hydrophobic interactions are mainly responsible for the higher partition coefficients of cytochrome-c in aqueous two-phase systems at pH 14, and the extraction and separation capacity of biomolecules can be improved by the modulation of the relative hydrophobicity of the phases and/or the pH of the system. [Copyright &y& Elsevier]

Material preparation in ionic liquids and environmental pollution control by ionic liquids are often closely dependent on the aggregation behavior of ionic liquids in solution. In the present work, conductivity, fluorescence probe, and dynamic light scattering techniques have been used to study the effect of organic solvents on the aggregation behavior of 1-dodecyl-3-methylimidazolium bromide in water. It was shown that the critical aggregation concentration (CAC), the ionization degree of the aggregates (α), and the standard Gibbs energy of aggregation (ΔGm°) of the ionic liquid increase, while its aggregation number (Nagg) and aggregates’ size decrease with increasing concentration of organic additives in water. These results have been discussed from the favorable interactions of alkyl chain of the ionic liquid with the mixed solvents. It is suggested that the solvophobic parameter, characterized quantitatively by Gibbs energy of transfer of hydrocarbon from gas into a given solvent, can be used to account for the effect of organic additives on the formation and growth of the ionic liquid aggregates in water. Aggregation behavior of ionic liquids in aqueous organic solutions can be modulated simply by the solvophobic parameters of hydrocarbon in the mixed solvents. [ABSTRACT FROM AUTHOR]

A zinc-based ionic liquid ([CHCl][ZnCl2]2) was found to be an excellent reaction medium for the direct nucleophilic substitution reactions of alcohols. The high conversion, high selectivity, easy separation procedure, catalyst reusability and no necessity of excessive nucleophiles make the chemical process cleaner. This reaction was believed to work through the carbocation mechanism and the existence of carbocation was detected by UV-vis spectroscopy. It was suggested that the hydroxyl group on the choline cation was the major inducement for the formation of special microstructures which could provide adequate stability for the carbocation in the reaction systems and increase the reactivity and selectivity. [ABSTRACT FROM AUTHOR]

Abstract: Information on the interactions between ionic liquids and molecular solvents are essential for the understanding of the function of ionic liquids in related procedures, and excess properties are sensitive probe for these interactions. In this work, excess molar volume and excess logarithmic viscosity ((ln η)E) for the binary mixtures of 1-hexyl-3-methylimidazolium tetrafluoroborate ([C6mim][BF4]) with butanone, ethyl acetate, butylamine, and tetrahydrofuran have been determined from density and viscosity measurements in the whole composition range at the temperature of 298.15K. It is found that for the studied systems, the values of are negative but those of (ln η) E are positive in the whole concentration range. The values show their minimum at the ionic liquid mole fraction of 0.3, and (ln η) E values exhibit a maximum at the same composition. The absolute values of follow the sequence: tetrahydrofuran>butanone>ethyl acetate>butylamine for the binary systems, whereas the values of (ln η) E decrease in the order: tetrahydrofuran>butylamine>ethyl acetate>butanone. The results have been analyzed through the ion–dipole interaction, the hydrogen bonding, the packing efficiency and the ion-pairs exist in the ionic liquid. [Copyright &y& Elsevier]