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The reversible phase transfer of compounds between two immiscible liquid phases has many applications in a wide range of fields, and ionic liquids have been widely used as potential functional solvents and catalysts. However, photo-triggered reversible phase transfer of ionic liquids between the organic phase and water phase has not been reported so far. In the present work, the reversible phase transfer of six kinds of azobenzene-based ionic liquid surfactants between the organic phase and water phase is investigated by alternative irradiation of UV and visible light. Factors affecting the transfer efficiency, such as chemical structure and concentration of the ionic liquid surfactants, equilibrium photo-isomerization degree, and the aggregation state of ionic liquid surfactants are investigated in detail. It is shown that transfer efficiency greater than 89% was achieved under optimal conditions, equilibrium photo-isomerization degree of the ionic liquid surfactants is the main factor to determine their transfer efficiencies, and the aggregation of cis -isomers is not beneficial for the transfer.

Recently, the efficient chemical fixation of carbon dioxide (CO₂) into high value chemicals without using noble metal catalysts has become extremely appealing from the viewpoint of sustainable chemistry. In this work, a one-pot three component reaction of propargylic alcohols, anines and CO₂ that can proceed in an atom economy and environmentally benign manner by combination of CuI and tetrabutylphosphonium imidazol ([P 4444 ][Im]) as a catalyst was described. Catalysis studies indicate that this catalytic system is an effective catalyst for the conversion of CO₂ into oxazolidinones at room temperature and ambient pressure without any solvent. The results provide a useful way to design novel noble metal-free catalyst systems for the transformation of CO₂ into other valuable compounds., Competing Interests: The authors declare no conflict of interest.

As a class of green and designable solvents, ionic liquids (ILs) have been used extensively in inorganic synthesis. In those schemes, ILs were usually used as reaction media to replace water and organic solvents, and/or used as stabilizer and capping agents to act like an amphiphilic molecule or polymer. However, the unique properties of ILs were not fully utilized in the area of material preparation. In this study, a new protocol of "ILs-water interfacial synthesis" was developed and used for the preparation of Ag nanomaterials. Taking the advantage of tunable property of ILs-water interface, Ag nanomaterials with different morphology such as triangular nanoplates, polygonal nanoplates, and nanoparticles could be facilely obtained. Growth mechanism of the triangular Ag nanoplates has been investigated from structural characterization and molecular dynamics (MD) simulation. It was shown that growth of the nanoplates was under kinetic control mainly due to high viscosity and ionicity of the ILs. Furthermore, the antimicrobial performance of these Ag samples was tested to study the influence of shape of the Ag nanomaterials on the antimicrobial activity and the related antimicrobial mechanism. The results suggested that the efficient antimicrobial activity of the triangular Ag nanoplates was ascribed to their sharp corners and edges and large areas of active (111) crystal plane, which leads to the higher amount of leaching Ag(+) ion., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Thermodynamic dissociation constants of the Brønsted acidic ionic liquids (ILs) are important for their catalytic and separation applications. In this work, a series of imidazolium bromides with one carboxylic acid substitute group in their alkyl chain ([{(CH2)nCOOH}mim]Br, n = 1,3,5,7) have been synthesized, and their dissociation constants (pKa) at different ionic strengths have been determined in aqueous and aqueous organic solvents at 0.1 mole fraction (x) of ethanol, glycol, iso-propanol, and dimethyl sulfoxide by potentiometric titrations at 298.2 K. The standard thermodynamic dissociation constants (pKa(T)) of the ILs in these solvents were calculated from the extended Debye-Hückel equation. It was found that the pKa values increased with the increase of ionic strength of the media and of the addition of organic solvent in water. The pKa(T) values also increased with the increase of the alkyl chain length of cations of the ILs. In addition, the effect of solvent nature on pKa(T) values is interpreted from solvation of the dissociation components and their Gibbs energy of transfer from water to aqueous organic solutions.

Recently, it has been reported that addition of a cosolvent significantly influences solubility of cellulose in ionic liquids (ILs), but little is known about the influence mechanism of the cosolvent on the molecular level. In this work, four kinds of typical molecular solvents (dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), CH₃OH, and H₂O) were used to investigate the effect of cosolvents on cellulose dissolution in [C₄mim][CH₃COO] by molecular dynamics simulations and quantum chemistry calculations. It was found that dissolution of cellulose in IL/cosolvent systems is mainly determined by the hydrogen bond interactions between [CH₃COO](-) anions and the hydroxyl protons of cellulose. The effect of cosolvents on the solubility of cellulose is indirectly achieved by influencing such hydrogen bond interactions. The strong preferential solvation of [CH₃COO](-) by the protic solvents (CH₃OH and H₂O) can compete with the cellulose-[CH₃COO](-) interaction in the dissolution process, resulting in decreased cellulose solubility. On the other hand, the aprotic solvents (DMSO and DMF) can partially break down the ionic association of [C₄mim][CH₃COO] by solvation of the cation and anion, but no preferential solvation was observed. The dissociated [CH₃COO](-) would readily interact with cellulose to improve the dissolution of cellulose. Furthermore, the effect of the aprotic solvent-to-IL molar ratio on the dissolution of cellulose in [C₄mim][CH₃COO]/DMSO systems was investigated, and a possible mechanism is proposed. These simulation results provide insight into how a cosolvent affects the dissolution of cellulose in ILs and may motivate further experimental studies in related fields.

Aqueous solutions of five ionic liquids (ILs) of the 1-n-alkyl-3-methylimidazolium bromide family, [C(n)mim]Br (n = 4, 6, 8, 10, 12), were investigated by NMR measurements at 298.2 K as a function of IL concentrations. Critical aggregation concentrations and aggregation numbers of these ILs were determined by 1H NMR except for [C4mim]Br in D2O. The effects of the alkyl chain length of the cations were examined on the aggregation behavior of the ILs. 1H NMR data of the solvent D2O were used to investigate the hydration of the ILs in D2O, and it was found that the ionic hydration and the cation-anion association or aggregation of the ILs offset each other. The microenvironment of different protons of cations of the ILs in the aggregates was probed by determining the spin-lattice relaxation rate (1/T1). It is suggested that the imidazolium rings in the aggregates are exposed to water and that the molecular motion of the aggregates is more restricted than that of the monomers of the ILs. Furthermore, a stair-like microscopic aggregation structure is suggested for the [C(n)mim]Br/D2O (n = 6, 8, 10) systems from 2-D 1H-1H NOESY measurements.

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]

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]

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]

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]

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]

Abstract: Ionic liquids have potentials as green materials in a variety of fields. It is the case that in their application in industry, ionic liquids are often used together with molecular solutes/solvents. In this paper, systematical measurements of viscosities and conductivities for the binary and quasi-binary mixtures of ionic liquids with molecular solutes were performed over the whole concentration range. The variation tendency of viscosities/conductivities with composition of the mixtures was explained through the disruption of molecular solutes to ionic association or aggregation of the ionic liquids. A exponential equation with empirical parameter A suggested initially by Seddon et al. was used to describe the dependence of viscosities on the mole fraction of molecular solutes, and the physical meaning of A was analyzed based on a theoretical equation deduced from rate process theory. At the same time, another exponential equation with parameter C was proposed to correlate the experimental date of the product of conductivity and viscosity, and satisfactory results were obtained over the entire range of concentration. The main factors affecting the parameter C were discussed. It is expected that the new data and correlation equations reported in this work will be useful for the application of ionic liquids in chemical industry. [Copyright &y& Elsevier]

Porous gold with well-defined shape and size have aroused extensive research enthusiasm due to their prominent properties in various applications. However, it is still a great challenge to explore a simple, green, and low-cost route to fabricate porous gold with a "clean" surface. In this work, porous worm-like Au has been easily synthesized in a one-step procedure from aqueous solution at room temperature under the action of ionic liquid tetrapropylammonium glycine ([N3333][Gly]). It is shown that the as-prepared porous worm-like Au has the length from 0.3 to 0.6 μm and the width of approximately 100–150 nm, and it is composed of lots of small nanoparticles about 6–12 nm in diameter. With rhodamine 6G (R6G) as a probe molecule, porous worm-like Au displays remarkable surface enhanced Raman scattering (SERS) sensitivity (detection limit is lower than 10−13 M), and extremely high reproducibility (average relative standard deviations is less than 2%). At the same time, owing to significantly high specific surface area, various pore sizes and plenty of crystal defects, porous worm-like Au also exhibits excellent catalytic performance in the reduction of nitroaromatics, such as p-nitrophenol and p-nitroaniline, which can be completely converted within only 100 s and 150 s, respectively. It is expected that the as-prepared porous worm-like Au with porous and self-supported structures will also present the encouraging advances in electrocatalysis, sensing, and many others. [ABSTRACT FROM AUTHOR]

Fast, efficient capture and safe storage of radioactive iodine is of great significance in nuclear energy utilization but still remains a challenge. Here we report imidazolate ionic liquids (Im-ILs) for rapid and efficient capture, and reliable storage of iodine. These Im-ILs can chemically capture iodine to form I-substituted imidazolate ILs with an iodide counterion and the newly formed ILs can absorb iodine to form polyiodide species and low-temperature eutectic salts. For example, choline imidazolate shows iodine capture capacities of 8.7 and 17.5 g of iodine per gram of IL at 30 and 100 oC, respectively, which are, to the best of our knowledge, higher than the values (0.5–4.3 g/g) reported to date. Importantly, iodine can be stably stored in the Im-IL absorbent systems even at 100 oC. The Im-ILs have potential for application in the capture and storage of radioactive iodine. Efficient capture of iodine has important applications in nuclear waste processing. Here a class of imidazolate-derived ionic liquids are shown to chemically capture up to 17.5 grams of iodine per gram of ionic liquid at useful temperatures. [ABSTRACT FROM AUTHOR]

Volume and viscosity data of ionic liquid (IL)-molecular solvent mixtures are very important for the design of process engineering involving these mixtures. In this work, densities and viscosities for the binary solutions of [C n mim]Br (n = 4, 6, 8) ionic liquids with methanol, 1-propanol, and 1-pentanol have been determined at 298.15 K as a function of IL concentrations. From these experimental data, apparent molar volumes, standard partial molar volumes, and viscosity B -coefficient of ILs were derived. The effect of the alkyl chain length in the imidazolium cation and properties of alcohol on the standard partial molar volumes of ILs and viscosity B -coefficient was discussed. In a given alcohol, the standard partial molar volumes of ILs and viscosity B -coefficient increase linearly with increasing alkyl chain length of ILs. For a given IL, unexpectedly, its standard partial molar volume in the three molecular solvents is not a constant, but increases in the order: 1-pentanol > 1-propanol > methanol. The viscosity B -coefficients of a given IL in the alcohols also change in the same sequential order. These results suggest that the interactions between ILs and the alcohols increase with the decrease of alkyl chain length of the alcohols. [ABSTRACT FROM AUTHOR]

Pd/C-[BMIm][BF 4 ] catalyst displayed high activity for acceptorless dehydrogenation of biomass-derived alcohols to produce aromatic ketones under mild conditions without any acid/base additives, and this catalyst could be recovered and reused for 5 runs without obvious activity loss. This work provides a potential approach for the effective utilization of renewable biomass resources to produce aromatic compounds and clean H 2. [Display omitted] • The combination of Pd/C with specific ionic liquid of 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF 4 ]) displayed high activity for the dehydrogenation of aromatic alcohols to produce aromatic ketones. • The Pd/C-[BMIm][BF 4 ] pair promoted the dehydrogenation of aromatic alcohols and inhabited the hydrogenation of aromatic alcohols. • The catalyst could be recycled for 5 runs without obvious loss of activity. • Pd/C could be anchored and stabilized by the IL through interacting with [BMIm]+ cation, and both the [BMIm]+ cation and the [BF 4 ]- anion play vital roles in activating hydroxyl-H and hydroxyl α-H of the aromatic alcohol. Acceptorless dehydrogenation of alcohols is a promising pathway for biomass resource utilization and hydrogen supply, but still lacking for simple and effective catalysts. Herein, we report a metal-ionic liquids (ILs) catalyst for synergistical catalytic dehydrogenation of aromatic alcohols to aromatic ketones under mild conditions without any acid/base additives. It is found that the combination of Pd/C with 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF 4 ]) displays high activity for the dehydrogenation of biomass-derived alcohols including 1-phenyl-1-ethanol, 1-phenyl-1-propanol and 1-(4-methoxyphenyl)ethanol. Mechanistic studies reveal that the Pd/C can be anchored and stabilized by the IL via interacting with [BMIm]+ cation, and the [BF 4 ]- anion plays vital role in the activation of hydroxyl-H and α-H protons via hydrogen bonding interactions. These interactions create an effective microenvironmental for Pd/C catalyzing the cleavage of the hydroxyl-H and α-C H bonds of α-hydroxyl aromatic alcohols to generate aromatic ketones and H 2. Moreover, the Pd/C-[BMIm][BF 4 ] catalyst could be recovered and reused for 5 runs without obvious activity loss. This strategy provides more evidences for the synergetic catalysis of metal and ionic liquids and exhibits potential application prospects for hydrogen supply from renewable biomass-derived alcohols. [ABSTRACT FROM AUTHOR]

Abstract At present, it is still a challenge for reversible regulation of phase behavior and microstructure of microemulsions with less energy input and no composition change of the system. Photo-responsive microemulsions provide a potential way to solve these problems. In this work, 10 kinds of photo-responsive ionic liquids (ILs) with azobenzene group were used as photo-responsive surfactants to form microemulsions with water and some alcohols. Factors affecting the phase behavior and sub-regions of microemulsions, such as chemical structure of the ILs, temperature, alcohols properties and UV irradiation, were studied by conductivity, small-angle X-ray scattering, dynamic light scattering and cryo-TEM techniques. It was found that azobenzene-based ILs with a more hydrophilic head group and a shorter alkyl spacer length were favor of the formation of the microemulsions. The phase behavior of the microemulsions only slightly changed after UV irradiation, however, the area of O/W and bi-continuous sub-regions of the microemulsion could be regulated by UV irradiation. At the same time, droplets size increased after UV light irradiation, and could be restored close to the initial value by alternative vis-light irradiation. Highlights • Photo-responsive microemulsions were formed by azobenzene-based ionic liquids as photo-responsive surfactants. • Factors affect the phase behavior were investigated. • The area of sub-regions of the microemulsion could be regulated by UV irradiation. • The droplets size could be modulated by alternatively irradiation of UV and visible light. [ABSTRACT FROM AUTHOR]

Abstract Stimuli-responsive Pickering emulsions have attracted increasing interest because of the advantages of applications in numerous industrial processes. In this work, Pickering emulsions have been obtained by using negatively charged silica nanoparticles in association with very small amount of CO 2 -responsive ionic liquids as stabilizer. Ionic liquids N -alkylimidazole bicarbonates ([C n im]+HCO 3 −, n = 6, 8, 10, 12, 14) are in-situ generated by bubbling CO 2 into aqueous solution of N -alkylimidazoles (C n im, n = 6, 8, 10, 12, 14), and this process is reversible by removal of CO 2 with bubbling of N 2. Thus the Pickering emulsions may be switched multiple times between emulsification and demulsification states by alternatively bubbling and removal of CO 2 at 25 °C. The effect of concentration and alkyl chain length of [C n im]+HCO 3 − on Pickering emulsions is investigated systematically, and the possible mechanism of CO 2 -responsive Pickering emulsion is also studied by conductivity, surface tension, zeta potential, adsorption isotherm, water contact angle and 13C NMR spectroscopy. This CO 2 -responsive Pickering emulsion is cheap, simple, eco-friendly, and may have potential applications in emulsification and demulsification. Graphical abstract For the first time, in situ generated ionic liquids N -alkylimidazole bicarbonates were used as a emulsifier to prepare CO 2 -responsive Pickering emulsions, which may be switched between emulsification and demulsification by alternatively bubbling and removal of CO 2 at room temperature. Unlabelled Image Highlights • Emulsion was stabilized by silica and very small amount of ionic liquids. • Formation and breaking of emulsion was reversible by bubbling and removal of CO 2. • Minimum concentration of Ionic liquids required is 83 times smaller than its CMC. • The possible mechanism for the CO 2 -responsive Pickering emulsion is studied. [ABSTRACT FROM AUTHOR]

Developing a simple and green route for the controlled synthesis of hierarchical nanomaterials with anisotropic particles as subunits is highly desirable and technically important. Here, a functionalized ionic liquid (FIL) assisted strategy is developed for the preparation of hierarchical Au nanomaterials at room temperature. Various morphologies of Au products, including nanoplate-built flowers, nanobar-built flowers and nanourchins, have been well achieved using the current route in aqueous solutions of imidazolium ILs with different functional groups, such as 1-carboxymethy-3-methylimidazolium chloride ([CMmim]Cl), 1-hydroxylethyl- 3-methylimidazolium chloride ([HEmim]Cl), and 1-(3-aminopropyl)-3- methylimidazolium chloride ([APmim]Cl). The influence of these FILs on the morphology of Au products and their growth process has been studied systematically. It is shown that the functionalized ILs play important roles in the construction of these interesting Au hierarchies. The seed, IL concentration (within a certain range), reaction temperature have negligible influence, but stirring and anions of the ILs have important influences, on the product morphologies. Based on these results, the possible growth mechanism is proposed for the formation of different Au hierarchies. In addition, all the Au samples prepared with the assistance of the functionalized ILs, especially the nanoplate-built flowers, exhibit striking SERS sensitivity and high reproducibility. [ABSTRACT FROM AUTHOR]

Searching for environmentally friendly aqueous two-phase systems is imperative for the sustainable development of separation technologies. In this work, five kinds of environmentally benign choline derivative ionic liquids were synthesized and used for the formation of aqueous two-phase systems with K 3 PO 4 , K 3 C 6 H 5 O 7 or K 2 CO 3 . In order to understand the phase formation processes of these aqueous two-phase systems and their possible application in extraction, phase diagrams and partition coefficients of purine alkaloids were determined at T  = 298.2 K, and the effects of structure of the ionic liquids, nature of the purine alkaloids, composition and temperature of the systems on the partitioning behaviour of purine alkaloids were investigated systematically. It was shown that caffeine, theobromine and 2,6-amino purine could be extracted effectively into the ionic liquid-rich phase of the aqueous two-phase systems, and the partition coefficients were as high as 4.5–42 under the optimized conditions. The partitioning was found to decrease with the increase of the ratio of H 2 O weight fraction (in the ionic liquid-rich phase and in the salt-rich phase) and hydrophobicity of both the purine alkaloids and the ionic liquids, but not sensitive to the change of temperature. [ABSTRACT FROM AUTHOR]

High current density at specific CO/H 2 molar ratios is the key to the industrial application of heterogeneous electrocatalytic CO 2 reduction reaction (CO 2 RR) to syngas, which is still very challenging. Here, we report a Ni-foam-supported nano-Ag catalyst for CO 2 RR in ionic liquid (IL)-acetonitrile electrolyte originally designed for CO 2 RR-to-CO. It is surprising to find that this is a highly efficient catalytic system for CO 2 RR-to-syngas, the CO/H 2 molar ratio in the syngas can be tuned from 1:5–26:1, and the current density is as high as 363.6, 458.2, and 644.7 mA cm−2 at the CO/H 2 molar ratios of 1:1, 1:2, and 1:3, respectively. The high efficiency of CO 2 RR-to-syngas is attributed to the synergistic stabilization action of nano-Ag and IL cationic C4/5-H for intermediate *COO- to produce CO, as well as cationic C2-H contribution to hydrogen evolution. This work opens a new way to improve catalytic performance of CO 2 RR-to-syngas. [Display omitted] • A nano-Ag catalyst in-situ grown on Ni foam was developed for CO 2 RR-to-syngas in [C 4 mim][PF 6 ]/MeCN electrolyte. • The CO/H 2 molar ratio could be tuned from 1:5–26:1, and the current density was high up to 644.7 mA cm−2. • By replacing the C2-H with methyl, the CO 2 RR product could be readily switched from syngas to pure CO, and the current density is high up to 528.3 mA cm−2. • A new pathway was explored to enhance CO 2 RR-to-syngas performance by adjusting the active protons of imidazolium ionic liquids. [ABSTRACT FROM AUTHOR]

• Stable ionic liquid hybrid Al-fum MOF materials were prepared by simple impregnation approach. • [C 2 N][Zn 3 Cl 7 ]@Al-fum-60% exhibit an exceptionally high uptake at high temperature (9.9 mmol/g at 80 °C, 8.8 mmol/g at 100 °C) • [C 2 N][Zn 3 Cl 7 ]@Al-fum-60% have an excellent selective separation performance of NH 3 from NH 3 /CO 2 mixture at 80 °C. • Coordination interactions of NH 3 to Zn centre is the key driven force for the adsorption and selective separation. Efficient adsorption and selective separation of ammonia at high temperature is a crucial and challenging issue. In this work, a series of stable ionic liquid hybrid materials have been developed by simple impregnation of ionic liquids into stable metal–organic framework Al-fum with 1D pores. The hybrid material [C 2 N][Zn 3 Cl 7 ]@Al-fum-60% exhibited an exceptionally high uptake (9.9 mmol/g at 80 °C, 8.8 mmol/g at 100 °C) at high temperature, excellent uptake (9.8 mmol/g at 25.0 °C) at low ammonia concentration (100,000 ppm), and remarkable selective separation performance (selectivity factor is 25.1) of NH 3 from NH 3 /CO 2 mixture at high temperature. The NH 3 uptake of [C 2 N][Zn 3 Cl 7 ]@Al-fum-60% at 100 °C was higher than the capacity of most of typical porous NH 3 adsorbents at room temperature. It is revealed that such superior NH 3 capacity and selective separation performance are mainly attributed to coordination interactions of NH 3 to Zn centre of the ionic liquids and the hydrogen bonding interactions of NH 3 with Cl of the ionic liquids and NH 3 with μ-OH of Al-fum. [ABSTRACT FROM AUTHOR]

Recycling of rare earth metals is important for their supply risk in the future. In this work, a greener and highly efficient liquid-liquid extraction strategy is presented for rare earth metals from aqueous solution with PEG-functionalized ionic liquids. The factors influencing the solvent extraction process such as phase volume ratio, equilibrium time, pH value of aqueous phase, alkyl chain length of the ionic liquids and temperature of the system were investigated systematically. It was found that under optimal conditions, the single-step extraction efficiency was > 96.8% for the studied 11 kinds of rare earth metal ions Sc(III), La(III), Ce(III), Y(III), Nd(III), Sm(III), Gd(III), Dy(III), Ho(III), Yb(III) and Lu(III). After the extraction, about 100% of the rare earth metals could be stripped from the ionic liquids phases by using dilute aqueous oxalic acid, and the ionic liquids would be recovered and reused in the next extraction process. In addition, the extraction mechanism was investigated in some details, and an ion pair association mechanism was suggested. Since the extraction procedure was performed without saponification, addition of extra extractant, organic diluents or salt, the approach described here has the potential to be used as a sustainable strategy for the separation and enrichment of rare earths from complex matrixes. [ABSTRACT FROM AUTHOR]

Ionic liquids are widely recognized new materials in carbon dioxide capture and separation technology. In this work, we synthesized and characterized two kinds of ether-functionalized imidazolium ionic liquids, 1-methoxyethyl-3-methylimidazolium hexafluoroborate ([EOMmim][PF 6 ]) and 1-methoxyethyl-3-methylimidazolium bis(trifluoro-methylsulfony)imide ([EOMmim][Tf 2 N]). Solubility values of CO 2 in these ionic liquids were determined by isometric weight method at the temperatures from 298.15 K to 343.15 K and the pressure up to 5.185 MPa. Furthermore, solubilities of other flue gases, N 2 and O 2 , in these two ionic liquids were also measured at 303.15 K. It was shown that little influence had been exerted on CO 2 solubility by the introduction of ether groups on the cation, but it decreased N 2 and O 2 solubility, resulting in the remarkable increase of CO 2 /N 2 and CO 2 /O 2 selectivity. In addition, the solubility data were well correlated by Pitzer model, and the standard state solution Gibbs energy, solution enthalpy and solution entropy of CO 2 in the two ionic liquids were reported. Regeneration characteristics of the investigated ionic liquids was also studied by vacuum desorption and atmospheric desorption, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hydrophobic ionic liquids (ILs) and water stable MOFs were used to construct IL hybrid MOF materals. • IL was highly dispersed in the nanopores of MOFs to expose significantly more active adsorption sites. • IL@MOF hybrid materals exhibit a record I 3 − absorption capacity due to high dispersion of IL in MOF nanopores. • Multiple sites cooperative interactions of I 3 − with highly dispersed IL is the key driven force for the adsorption. The development and utilization of nuclear energy is one of the effective ways to reduce carbon emissions and achieve the goal of global carbon neutrality. However, it is inevitable to release radioactive pollutants, such as I 3 −, into the environment during the utilization of nuclear energy, and the efficient adsorption and storage of iodide ion remains a challenge. In this work, a series of ionic liquid (IL) hybrid metal–organic framework (MOF) materials have been developed by simple impregnation of hydrophobic ILs into nanopores of stable MOFs for high-efficient I 3 − absorption from water for the first time. It is found that the hybrid materal [C 2 mim][Tf 2 N]@UiO-67–30 % exhibits a record high I 3 − absorption capacity at room temperature (4.30 g·g−1), and the I 3 − absorption capacity of [C 2 mim][Tf 2 N] in UiO-67–5 % is 10 times that of the neat [C 2 mim][Tf 2 N]. The adsorption process can be well described by Freundlich model and pseudo-second-order model. Such superior I 3 − absorption capacity is mainly attributed to the multiple sites interaction between anion of the highly dispersed IL and I 3 −, although cation of the IL and benzene ring of MOF framework also have contribution for the adsorption. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two series of cationic and anionic fluorinated ionic liquids were synthesized. • These fluorinated ILs, even with short fluorocarbon chain lengths, exhibit superior surface activity in ionic liquid solvents. • The microstructure of these IL-in-IL aggregation systems were characterized by dynamic light scattering and small-angle X-ray scattering. • The nanosize IL-in-IL aggregation system was proposed as an efficient nanoreactor to prepare nanoscale MOFs. • IL-in-IL system has the fascinating role both of nanoreactor and in situ anchoring ionic liquids active sites. The design of thermostable and efficient self-assembly nanoreactors is highly desirable for the fabrication of nanomaterials. Benefiting from the tunable properties and nonvolatility of ionic liquids (IL), IL-in-IL self-assembly systems show a flexible structure and thermostability under extreme conditions. Inspired by this hypothesis, stronger hydrophobic fluorinated ILs are expected to fabricate nonvolatile IL-in-IL self-assembly systems. In this work, two series of fluorinated ILs were synthesized and characterized by NMR, FTIR, DSC, and TGA. Then, the aggregation of these fluorinated ILs in protic and aprotic IL solvents was studied by surface tension and 19F NMR methods. The microstructure of these IL-in-IL aggregation systems was characterized by DLS and SAXS. The fluorinated ILs exhibit excellent surface activity even in aprotic ILs. Furthermore, protic ILs display superior ability to promote the self-assembly of ILs surfactants. These IL-in-IL aggregation systems display the typical morphology of ellipsoidal or multilayer spherical micelles with diameters of approximately 10 nm ∼ 60 nm. A typical IL-in-IL aggregation system was proposed as an efficient nanoreactor to prepare nanoscale MOFs without using any volatile organic solvents or autoclaving. The synthesized HKUST-1 exhibits larger surface areas and nanoscale morphology by XRD, SEM, TEM, BET, and XPS characterization. The results presented in this study offer key information to design new thermostable IL-based colloidal systems and their applications. [ABSTRACT FROM AUTHOR]

The development of a simple, template-free, and one-step strategy to synthesize nanostructured Au architectures with fascinating morphology is highly desirable and technically important due to their valuable applications in varied fields. In this work, the “green” strategy of “tunable ionic liquids-water (ILs-H 2 O) interfacial synthesis” developed previously by us is utilized for feasible synthesis of gold needle mushroom-like micro/nanostructures at the 1,3-dibutylimidazolium bis(trifluoromethylsulfonyl)imide ([C 4 bim][Tf 2 N]) - water interface and ambient conditions. The as-obtained gold needle mushrooms (AuNMs) have been characterized and analyzed systemically by scanning electron microscopy, X-ray powder diffraction, energy-dispersive X-ray spectroscopy, and transmission electron microscopy. It is shown that the as-prepared AuNMs can be used as substrates to perform surface enhanced Raman scattering (SERS) investigation with striking SERS sensitivity. By employing ILs with different alkyl chain lengths of the imidazolium cations and/or different nature of anions, Au nanomaterials with diverse morphologies can be easily prepared at different ILs-H 2 O interfaces. Based on the analysis of the control experiments, the growth and formation of AuNMs at the [C 4 bim][Tf 2 N]-H 2 O interface have been discussed. [ABSTRACT FROM AUTHOR]

In the present work, seven 1-allyl-3-methylimizodalium carboxylate ionic liquids (ILs), including 1-allyl-3-methylimizodalium formate [Amim][HCOO], acetate [Amim][CH 3 COO], propionate [Amim][CH 3 CH 2 COO], butyrate [Amim][CH 3 (CH 2 ) 2 COO], glycollate [Amim][HOCH 2 COO], lactate [Amim][CH 3 CHOHCOO]) and benzoate [Amim][C 6 H 5 COO], have been synthesized and characterized. Density ( ρ ) and conductivity ( σ ) have been determined experimentally for these ILs at 298.15 K and atmospheric pressure. Then molar volume ( V m ), standard entropy ( S °), lattice energy ( U POT ) and molar conductivity ( Λ ) of the ILs have been derived from the density and conductivity data. Ionicity of the ILs has been estimated using the Walden plot. Meanwhile, how anionic structure of the ILs affects the volumetric and conductivity properties of 1-allyl-3-methylimidazolium carboxylate ILs has been discussed from the analysis of structure–property relationship. [ABSTRACT FROM AUTHOR]

Highlights • Self-assembly of long-chain ionic liquids in protic ionic liquids were studied. • The cmc values of the ILs surfactants in EOAN are smaller than those in water. • EOAN provides denser hydrogen bond network than EAN. • The driving force for the micellization is analyzed. [ABSTRACT FROM AUTHOR]

• A series of PEGylated ionic liquids were synthesized. • Physico-chemical properties of PEGylated ionic liquids were measured. • AOT-based PEGylated ILs exhibit good surface activity in aqueous solutions. • PEGylated ionic liquids exhibit typical low critical solution temperature phase behavior. • Thermal-regulated phase separation system has great promise to separate metal ions. How to design thermal-responsive functional ionic liquids that can respond in a reversible manner still remains a challenge for the construction of ionic liquid-based smart systems, and they easily find applications in various scientific fields, including phase transfer catalysis, smart soft materials, controlled drug delivery and green separation. In this work, a series of PEGylated ionic liquids were prepared, and their structures were confirmed by NMR and FTIR spectra. The thermal properties of these ionic liquids were characterized by DSC and TGA. In addition, their physicochemical properties were measured in detail, including density and viscosity. Different models were used to fit the density and viscosity data. The critical micelle concentrations of the Aerosol OT-based PEGylated ionic liquids were also determined by the surface tension method, and they exhibited good surface activity. Furthermore, these PEGylated ionic liquids exhibit typical low critical solution temperature phase behavior. To illuminate the underlying mechanism of thermal-induced phase separation, temperature-dependent FTIR spectra were used to analyze the interaction between ionic liquids and water molecules. Finally, the thermally regulated PEGylated IL phase separation system was proposed as an efficient strategy to separate heavy metal ions and rare earth metal ions from water media. The results presented here offer key information to design new thermoresponsive ionic liquids and their applications. [ABSTRACT FROM AUTHOR]

Highlights: [•] The microemulsions composed of cholinium-based ionic liquid, Triton X-100 and water have been prepared and characterised. [•] Ternary phase diagrams of the microemulsions have been established at T =298.15K. [•] The microemulsions exhibit IL-in-water, bicontinuous and water-in-IL microstructures. [•] Droplets with the size smaller than 20nm are formed in these IL-based microemulsions. [ABSTRACT FROM AUTHOR]

Abstract: Densities, conductivity, fluorescence and UV–vis absorption spectroscopy of glycyl dipeptide+ionic liquid (1-dodecyl-3-methylimidazolium bromide ([C12mim]Br))+water mixtures have been measured at different temperatures. From density data, the standard partial molar volume , standard partial molar volume of transfer for three glycyl dipeptides from water to aqueous [C12mim]Br solutions (Δt V o), partial molar expansibility and Hepler's constant have been calculated. Through the electrical conductivity measurements, the critical micellar concentration (c cmc) and a series of thermodynamic parameters of micellization of [C12mim]Br in aqueous glycyl dipeptide solutions are evaluated. Effects of temperature and hydrocarbon chain length of the glycyl dipeptides on the volumetric properties of dipeptides and critical micelle concentration (c cmc) of [C12mim]Br were examined. The pyrene fluorescence spectra were used to study the change of micropolarity produced by the interactions of [C12mim]Br with glycyl dipeptides, and the aggregation behavior of [C12mim]Br. From the results of UV–vis absorption spectra, the binding constant between dipeptide and [C12mim]Br above the c cmc was determined. [Copyright &y& Elsevier]

Highlights: [•] C8mim[Cl] up-regulates the expressions of CYP1A1, CYP2E1, or CYP3A in EMT6 cells. [•] CYPs may be involved in the metabolization of imidazolium-based ionic liquids. [•] C8mim[Cl]-mediated CYP3A induction may be PXR-dependent. [ABSTRACT FROM AUTHOR]

[Display omitted] • A series of single-tailed amphiphilic ionic liquids composed of [C 14 mim]+ and five kinds of anions are designed. • The synergistic effect of hydrophobic and π-π interaction plays a vital role in the vesicle formation. • The reversible structure transition between vesicle and micelle is observed by alternating CO 2 and N 2 bubbling. • This structure transition is due to the reversible formation of carbamate from the reaction between CO 2 and the anion of IL. The understanding of vesicle formation mechanism of ionic liquids (ILs) in aqueous solution is of great significance for the innovation and application of IL vesicles. In this work, a series of single-tailed amphiphilic ionic liquids (ILs) consisted of 1-tetradecyl-3-methylimidazolium [C 14 mim]+ and five kinds of anions have been designed to examine the regulation of anionic structures on the vesicle formation of ILs in water without any additives by surface tension, conductivity, cryogenic transmission electron microscopy, dynamic light scattering, small-angle X-ray scattering, and NMR spectroscopy. It is found that synergistic effect of hydrophobic and π-π interaction plays a vital role in the vesicle formation of 1-tetradecyl-3-methylimidazolium 1, 2, 3-benztriazole ([C 14 mim][1, 2, 3-Ben]). Interestingly, reversible structural transition between vesicle and micelle of this IL is observed by alternating CO 2 and N 2 bubbling due to the reversible formation of carbamate arising from the reaction between CO 2 and the anion of the IL. [ABSTRACT FROM AUTHOR]

[Display omitted] • A crosslinking Sb-NC/PoMXene network with fully-active species is designed. • The network greatly enhances ion/electron transport and alleviates volume variation. • Interweaved polar interfaces benefit rich binding/catalytic sites to polysulfides. • Long cyclability is achieved for 700 cycles with capacity retention over 99%. The performances of lithium-sulfur batteries (LSBs) depend heavily on sulfur hosts with the desired properties including excellent electronic conductivity, high sulfur loading, strong polysulfide capture, and active catalytic centers. Here, we demonstrate 2D partially oxidized Ti 3 C 2 T x MXene (PoMXene) can be cross-linked by Sb, N co-implanted carbon (Sb-NC) through Ti-O-Sb bond to synthetize Sb-NC/PoMXene. It is shown that the nanostructuring Sb-NC/PoMXene provides fast ion/electron transport channel and robust 3D architecture to alleviate volume variations. Significantly, the interweaved polar interfaces benefit rich binding sites from Sb nanoparticles, N atoms, TiO 2 and Ti 3 C 2 T x towards polysulfides, and the Sb-NC could catalytically accelerate redox kinetics, thus efficiently suppressing polysulfide shuttle. As a result, the Sb-NC/PoMXene/S hybrids represent high capacity (1148.4 mAh g−1 at 0.1C) and long cyclability (570.6 mAh g−1 after 700 cycles at 2C). When the sulfur loading is increased to 4 mg cm−2, the thick cathode still maintains a high areal capacity of 3.8 mAh cm−2 with a decay of only 0.10% per cycle over 100 cycles at 0.2C. The studies pave a novel pathway to design nanostructured electrodes and promote catalytic performances in LSBs. [ABSTRACT FROM AUTHOR]

Abstract: In this work, a series of novel room temperature ionic liquids (ILs) have been synthesized with cheap, naturally α-amino acid ester as cations and bis(trifluoromethylsulfonyl)imide as anion. The glass transition temperature and thermal decomposition temperature of these ILs, partition coefficients of some coumarins and purine alkaloids between water and the amino acid ester-based ILs at T =298.15K, and Gibbs energy, enthalpy and entropy changes for the transfer of caffeine and 6,7-dihydroxycoumarin from water to [LeuC2][Tf2N] have been determined. It is shown that these ILs are highly effective materials for the extraction of drug compounds like coumarin, 4-hydroxycoumarin, 7-hydroxycoumarin, 3-aminocoumarin, coumarin-3-carboxylic acid, 6,7-dihydroxycoumarin, 6,7-dihydroxy-4-methylcoumarin, caffeine, theobromine, theophylline, inosine, and 2,6-diaminopurine. The partition process is driven by enthalpy term, and partition coefficients of the drug molecules increase with the increase of hydrophobicity of both the drug molecules and the ILs. Furthermore, the possible partition mechanism has been investigated from 13C NMR measurements. [Copyright &y& Elsevier]

Abstract: Searching for environmentally friendly aqueous two-phase systems is imperative for the sustainable development of bioseparation technologies. In the present work, (liquid+liquid) equilibrium data have been determined experimentally for aqueous two-phase systems formed by the cholinium-based ionic liquids (cholinium glycollate, cholinium propionate, cholinium lactate, and choline chloride) and polymers {polypropylene glycol 400 (PPG400), polypropylene glycol 1000 (PPG1000), and poly(ethylene glycol)-block-poly(propylene glycol)-poly(ethylene glycol) (EO10PO90)}. The effects of anion type of the ionic liquids, the nature of the polymers and temperature of the systems are examined on the phase-forming capacity of the systems. Then the binodal results have been satisfactorily fitted to a three-parameter empirical equation. The tie-line data are well described by the Othmer–Tobias and Bancroft equations. [Copyright &y& Elsevier]

Abstract: Ionic liquids (ILs) are promising in the capture and separation of CO2. In this work, IL 1-n-butyl-3-methylimidazolium heptafluorobutyrate, [C4mim][CF3CF2CF2COO], has been synthesized and characterized by 1H, 13C and 19F NMR spectra. Solubilities of CO2, H2, N2 and O2 in this IL have been determined at the temperature range from (303.15 to 333.15)K and the pressure up to 8.9MPa. From these data, the Henry’s constant, the standard state solution Gibbs energy, standard state solution enthalpy and standard state solution entropy of these gases in [C4mim][CF3CF2CF2COO] were derived and analyzed from molecular interactions. It was shown that the solubility of CO2 is obviously higher than that in [C4mim][CF3COO] and [C4mim][CF3SO3] reported in literature, which makes this IL an attractive solvent for gas separation processes. Furthermore, these solubility data were well correlated by Pitzer model. [Copyright &y& Elsevier]

Abstract: In this work, the hydrogen bond formation ability of cation and anion of the ILs was determined by using the solvatochromic method and was found to be responsible for their catalytic activity in the Knoevenagel reactions. The enhancement in the hydrogen bond donor ability of the cations and the hydrogen bond acceptor ability of the anions can both lead to the increase in the catalytic activity of the ILs. From the proposed reaction mechanism, it was deduced that the cations of the ILs can form hydrogen bond with aldehyde to activate the C electrophile, and the anions of the ILs can promote active methylene compound to produce carboanion as nucleophile, showing dual function activation effect in the catalytic processes. In addition, the optimized N,N-dimethylethanolamnium acetate as dual function activator for the Koevenagel reactions benefits from wide substrates tolerance, ambient reaction temperature, easy work-up procedure, and easy reuse of the IL. [Copyright &y& Elsevier]

Abstract: A novel method was proposed for successful fabrication of CuS nanostructures with various morphologies. At the ionic liquids (ILs)-modulated CHCl3–H2O interface, copper cupferronate [Cu(cup)2] in CHCl3 reacted with thiourea in water to generate CuS nanostructures via a solvothermal reaction process. The effects of alkyl chain length of imidazolium cations and nature of anions of the ILs, molar ratio of Cu(cup)2 to thiourea, the reaction temperature and time on the morphology of the products were studied systematically. It was shown that by changing alkyl chain length of imidazolium cations and nature of anions of the ILs, CuS nanostructures with various morphologies, including flowers, urchins, large nanodisks and nanoparticles, could be obtained at the liquid–liquid interface, and the ILs played important template roles in directing the formation of CuS nanostructures. Furthermore, the as-prepared CuS samples exhibited high catalytic activity for photodegradation of methyl orange and thermal decomposition of ammonium perchlorate. [Copyright &y& Elsevier]

Abstract: In this paper, the interactions between cationic dyes and the ionic liquids (ILs) have been studied by 31P nuclear magnetic resonance (NMR), UV–Vis spectroscopy and conductometric measurements at different temperatures. It was shown that a decrease in the measured specific conductance of the (dye+IL) mixtures was caused by the formation of non-conducting or less conducting (dye+IL) associates. The associates were formed by 1:1 ratio of cation of the cationic dyes and anion of the ILs by using the 31P NMR and UV–Vis spectroscopy methods. The association constants were calculated by theoretical model based on the deviation from linear behavior, and the association constants were as high as 106 (L·mol−1)2. Thermodynamic results imply that the formation process of association was exothermic nature. It is expected that the associates reported here would have promising application as active materials for the preparation of ion-selective electrode used in the determination of ILs concentrations. [Copyright &y& Elsevier]

Abstract: Alkylimidazolium salts are a very important class of ionic liquids (ILs). The ILs containing long alkyl chains are a kind of model surfactants. In this paper, the aggregation behavior of 1-decyl-3-methylimidazolium chloride ([C10mim]Cl) was investigated for the first time in aqueous monosaccharide (glucose, galactose, xylose and arabinose) solutions by conductivity, fluorescence, NMR and dynamic light scattering (DLS). Thus a series of physico-chemical parameters for the aggregation of [C10mim]Cl—the critical aggregation concentration (CAC), ionization degree of the aggregates (α), the standard Gibbs energy of aggregation (), and the aggregation number (N) were derived from the experimental data. The results show that addition of small amounts of monosaccharides in aqueous solution can cause a variation in aggregation properties of the IL. The CAC values decrease with increasing molality of monosaccharides. In particular for different kinds of monosaccharides, we found that the CAC values are in the order: glucose>galactose (hexoses), xylose>arabinose (pentoses); xylose>glucose (1e2e3e4e), arabinose>galactoses (1e2e3e4a). These trends may be attributed to the slight difference in the stereo-structure of monosaccharide molecules. Finally a mechanism for the interaction of these monosaccharides with [C10mim]Cl was proposed. [Copyright &y& Elsevier]

Abstract: A combination of CuI (10mol%) and [bmim]OAc (20mol%) in [bmim]PF6 was found to be a highly efficient and readily recyclable catalytic system for the synthesis of 2,3-disubstituted benzo[b]furans via three-component tandem reactions of 2-hydroxybenzaldehydes, amines and alkynes. Remarkable advantages of this new strategy include high efficiency, convenient recovery and efficient reuse of the catalytic system. [Copyright &y& Elsevier]

Abstract: In this work, aggregation behavior of [C12mim]Br in acetonitrile, ethylene glycol, N,N-dimethylformamide, formamide and dimethylsulfoxide solvents was investigated by conductivity and volume measurements. The critical aggregation concentration CAC, degree of anion binding β, and the standard Gibbs energy of aggregation ΔG o have been derived from the experimental data. Solvophobic parameters have been introduced to account for the interaction between alkyl chain of the IL and the solvents. It is shown that solvophobic effect and the hydrogen-bonding interaction between the IL anion and the solvents are the main factors affecting the aggregation of ILs in non-aqueous solvents. The aggregation of ILs in non-aqueous solvents can be controlled and regulated by solvent properties. [ABSTRACT FROM AUTHOR]

Abstract: In the present work, (liquid+liquid) equilibrium data have been determined experimentally for aqueous two-phase systems formed by the imidazolium ionic liquids of [C n mim][CH3COO] (n =4, 6, 8) and inorganic salts of K3PO4, K2HPO4, and K2CO3 at T =298.15K. Combined with available data in the literature, the effect of alkyl chain length of cations, type of anions of the ionic liquids, and nature of the inorganic salts were examined on the binodal curves of the systems. Then the binodal curves were fitted to a four-parameter empirical equation, and the tie-lines were described by the Othmer–Tobias and Bancroft equations. In addition, the extraction capacity of the {[C n mim][CH3COO] (n =4, 6, 8)+K3PO4} aqueous two-phase systems was evaluated through their application to the extraction of l-tryptophan. The high extraction efficiency suggests that these aqueous two-phase systems are feasible to be used in the extraction and separation process. [Copyright &y& Elsevier]

Abstract: The dependences of the absorption spectra of chrome azurol S (CAS) and Al3+–CAS complexes on the concentration of ionic liquids (ILs), 1-alkyl-3-methylimidazolium bromide ([C n Mim]Br, with n =8, 10, 12), were measured at 298.15K in aqueous solutions with pH=5.6. It is found that ILs can induce the significant red-shifts of the wavelength at the absorption maximum (λ max) of Al3+–CAS complex from 545 to 646nm for [C8Mim]Br, and to 642nm for [C12Mim]Br and [C16Mim]Br, respectively. Accompanying the red-shifts, the absorbance at λ max, and thereby molar absorptivity (ɛ), changes markedly with the IL concentration, and consequently the effect of ILs on the absorbance at λ max is systematically investigated in this work. Along with the experimental results of resonance light scattering, the sensitization mechanism is analyzed from the aggregation of the ILs and the interactions of ILs with CAS and Al3+–CAS complexes. It is shown that the hydrophobic interactions of IL subaggregates with CAS in Al3+–CAS complex are the crucial factor for the sensitization. [Copyright &y& Elsevier]

Abstract: Methyl orange (MO) exhibits a sensitive spectral signature to the polarity of medium environment. Using MO as the spectroscopic probe, this paper reports the results of studies on the aggregation of 1-alkyl-3-methylimidazolium-based ionic liquids (ILs, [C n mim]Br, n =8, 10, 12, and 16) in aqueous solutions. Along with the results obtained from the measurements of electrical conductivity and resonance light scattering (RLS), this investigation shows the characteristics of the IL aggregation and the properties of the bulk phase prior to the aggregation, and hence reveals the aggregation differences between surface active [C n mim]Br and traditional surfactants. It is shown that hydrogen bonds play a dominant role in the aggregation of ILs in addition to Coulombic and hydrophobic interactions. Compared with traditional cationic surfactant, IL displays the stronger aggregation due to the formation of the hydrogen bonded network. Also, such hydrogen bonded network results in the loose arrangements of imidazolium rings in the subaggregates of [C n mim]Br (n <10). When the mid-wavelength absorption band is just beginning to appear as the band of absorption maximum, the corresponding concentration is indicative of the formation of the perfect aggregates, and is in agreement with the critical aggregation concentration (CAC) of the ILs except [C8mim]Br. Moreover, it was found that the polarity in the core of the perfect IL aggregates is similar to the polarity within micelles of traditional cationic surfactant with the same alkyl chain length. [Copyright &y& Elsevier]

As is known to all, the alkyl chain is a perfect tool to regulate the microstructure of ionic liquid(IL) microemulsion directly. However, it is still a great challenge to design a new type of temperature-responsive IL with different alkyl chain length to construct the stimulus microemulsion. In this study, a new class of temperature-responsive IL microemulsions was built for the first time, which is composed by [P 444,n ]Br (n = 8,10,12,14,16,18), [C 12 mim]Br and H 2 O. The phase diagram and dynamic light scattering analysis revealed that the size of IL microemulsion droplets can be effective regulated by the alkyl chain length of temperature-responsive IL, so as to gain a series of organized structures. The molecular dynamic(MD) simulations were performed by a series of [P 444,n ]Br/[C 12 mim]Br/H 2 O mixture systems to illustrate this unique aggregation behavior of droplet. Simulation results are presented and discussed via the data of interaction energies, aggregation numbers, radial distribution functions (RDFs) and coordination numbers. The results indicate that the aggregation sizes of [C 12 mim]+ become smaller with the increase of alkyl chain length of tetrabutylphosphonium cation, which agrees well with experimental results. This is because that the weakened interaction of temperature-responsive IL and water molecules by the long alkyl chain could reduce the electrostatic repulsion of the polarity groups of the surfactants, which may decrease the size of the aggregate. These finding can help in further understanding the structure variation law of temperature-responsive IL microemulsions and thereby improve microemulsion theory. Unlabelled Image • A new class of temperature-responsive IL microemulsions was built. • The size of IL microemulsion droplets can be regulated by the alkyl chain length. • MD simulations were used to illustrate the unique aggregation behavior. • The long alkyl chain could reduce the electrostatic repulsion of the surfactants. [ABSTRACT FROM AUTHOR]

It is known that traditional microemulsions are thermodynamically stable mixtures which are extensively applied in many fields. However, how to control emulsification and demulsification of microemulsions more flexibly in practical applications is still a challenge. In the present study, a new type of temperature-sensitive ionic liquid (IL) microemulsion [P 4444 ][CF 3 COO]/[C 12 mim]Br/H 2 O, composed of two ILs and water molecules, was designed. Compared with traditional microemulsions, this IL microemulsion was more sensitive to the small range of temperature. Thus, the reversible emulsification and demulsification process can easily be switched by using temperature as a trigger. To elucidate the demulsification mechanism of this temperature-sensitive IL microemulsion, a series of molecular simulations were performed at different temperatures. The simulation results indicate that the interaction between [CF 3 COO]− and H 2 O is the driving force of demulsification process. In addition, the effect of [P 4444 ][CF 3 COO] and [C 12 mim]Br concentration on the microstructure of microemulsion was investigated rigorously. The results demonstrate that contents of both the [P 4444 ][CF 3 COO] and [C 12 mim]Br have an important influence on the demulsification behavior of IL microemulsion. Unlabelled Image • A new type of temperature-sensitive ionic liquid microemulsion was designed. • The reversible emulsification and demulsification process can easily be switched by using temperature as a trigger. • Molecular dynamics simulations were used to study the demulsification mechanism of temperature-sensitive IL microemulsion. • The interaction between [CF 3 COO]- and H 2 O is the driving force of demulsification process. [ABSTRACT FROM AUTHOR]