Functional Ionic Liquids Research Articles

Effects of ionic liquid [N4444] AOT on rice seedling growth cytomembrane damage and rhizobacteria resistance.

Ionic liquids (ILs) are solvents composed of ions, containing a large asymmetric cation with an anion. With increasing and widespread applications, the toxic effects of ILs have been considerable in recent years. This study explained the effects of the new functional ionic liquids [N4444] bis(2-ethylhexyl) sulfonyl succinate (AOT) on rice seedling and the growth of rhizobacteria. The rice seeds pretreated by [N4444] AOT revealed that it exhibited a significant negative impact on rice seedlings. The inhibition of rice growth increased with increasing concentration. When the concentration of [N4444] AOT increased to 0.25 and 0.5 mL L-1, the germination potential decreased by 40.0% and 86.3%, respectively, compared with the control. The germination potential and germination rate of rice were reduced, and the stress effect of ionic liquid on the root parts was higher than the aerial parts. The biomass of rice seedlings was decreased by 34.8 to 91.2%. Iodinic propane staining showed that by increasing concentration, the root cell cytomembrane damage level was increased and also changed the cell shapes, especially under 0.25 mg L-1 concentration stress. However, rhizobacteria of rice showed strong [N4444] AOT-resistant characteristics when the concentration was reached to 120 mg L-1. The ILs even more promoted the growth of Enterobacter sp. NP1142 and Pantoea sp. BR23. It was indicated that IL [N4444] AOT can be degraded easily by rhizobacteria to eliminate the eco-risk of ILs.

Highly ordered mesoporous functionalized pyridinium protic ionic liquids framework as efficient system in esterification reactions for biofuels production

Polysiloxane acidic ionic liquids containing pyridinium trifluoroacetate salts (PMO-Py-IL) were synthesized from pyridine containing organosilane precursors. Characterization by SEM, XRD, TGA, and nitrogen porosimetry confirmed that both pyridinium cation and trifluoroacetate anion were successfully incorporated within the organosilica network. The resulting organic-inorganic hybrid nanomaterial (PMO-Py-IL) was studied as nanocatalyst in free fatty acids esterification into biodiesel-like compounds. Remarkably, the synergistic hydrophilic/hydrophobic effect of pyridinium and trifluoroacetate ionic liquid in the well-ordered channels of PMO-Py-IL nanomaterial enhanced the activity toward sustainable biodiesel-like esters production. More importantly, PMO-Py-IL nanocatalyst also exhibited an exceptional activity and stability. The catalyst could be easily separated to reuse at least in ten reactions runs preserving almost intact its catalytic activity under otherwise identical conditions to those employed for the fresh catalysts.

Hydrophobic thermoplastic starch supramolecularly-induced by a functional sucrose based ionic liquid crystal

It is still a big challenge to obtain hydrophobic thermoplastic starch with outstanding mechanical performance due to the inevitable usage of typical hydrophilic plasticizers like glycerol during processing. Herein, we report a novel hydrophobic thermoplastic starch using a supramolecularly induced thermoplasticization technique. To achieve this aim, a functional sucrose-based ionic liquid crystal (ILC) including numerous chloride atoms has been firstly synthesized, and the obtained ILC molecules are then used as supramolecular inducers to thermoplasticize corn starch granules. Thermoplasticity and hydrophobicity of the prepared supramolecularly induced thermoplastic starch (STPS) with different ILC contents have been extensively investigated. Mechanism of the supramolecularly induced thermoplasticization has been investigated using molecular simulation as well. The prepared STPS with the maximum tensile strength of 8.4 MPa and water contact angle of about 117° show large potential applications in green and sustainable packaging materials.

Kinetics of phenol alkylation with tert-butyl alcohol using supported ionic liquid catalyst

Sulphonic acid functional ionic liquid was prepared by covalently bonded with mesoporous silica material (SBA-15). The physical structure, composition and functional groups were characterised. The prepared catalyst activity was investicated in tert-butylation of phenol with tert-butyl alcohol (TBA) was using a batch autoclave reactor. The different parameters like reaction time, reaction temperature, catalyst amount and reactant mole ratio on the conversion of phenol and selectivity towards 2‑tert-butyl phenol (4-TBP), 4‑tert‑butyl phenol (2-TBP) and 2,4-di‑tert‑butyl phenol (2,4-DTBP) was studied. Maximum phenol conversion of 72% was obtained at Lower tert‑butanol to phenol mole ratios and lower catalyst loading. The activation energy was found to be 4.2 kcal/mol with second order rate equation from the experimental data.

Biocompatible Ionic Liquid Promote One-Pot Synthesis of 2-Amino-4H-Chromenes Under Ambient Conditions

The synthesis of 2-amino-4H-chromenes through one-pot multicomponent reactions has received great attention due to the high atom efficiency and the broad bioactivities of the products. Here, the catalytic performances of a series of functional ionic liquids towards this type of reaction were investigated and the results showed that the ionic liquid, choline acetate ([Choline][Ac]), could efficiently promote this reactions under room temperature without the necessary of organic solvents. The reaction is easy to be conducted and the following work-up procedures are very simple. The pure products can be obtained through extraction and washing procedures, no column separation procedures are needed. Intriguingly, this reaction system can be easily scaled up to multi-gram, suggesting its perspective in industrial applications. In addition, the ionic liquid [Choline][Ac] can be easily prepared from cheap and biocompatible materials, and it can be feasibly recycled and reutilized for at least five cycles. Various aldehydes, malononitrile and activated phenols could be converted to the corresponding 2-amino-4H-chromenes with good to excellent isolated yields under the catalysis of choline acetate at room temperature.

Enhancing bio-catalytic activity and stability of lipase nanogel by functional ionic liquids modification

A novel integrated lipase nanogel based on functional ionic liquid modification and polymerization immobilization with improved stability was designed. Characterization before and after modification and polymerization was conducted using infrared spectroscopy, Circular dichroism spectroscopy, fluorescence spectroscopy, and scanning electron microscopy. It was shown that the modification of the ionic liquid influenced the catalytic behavior of lipase significantly due to the changed structure and surface properties of lipase. The enzymatic properties, including acid-base stability, thermal stability, organic solvents stability, and storage stability of CRL nanogel, were investigated in the p-nitrophenyl palmitate hydrolysis reaction (CRL, Lipase from Candida Rugosa). The results indicated that CRL nanogel has a better pH, heat, and organic solvent tolerance after immobilization. After seven weeks of storage, the natural CRL gradually lost its enzymatic activity, and only 17.5±1.7 % of the catalytic activity remained, the residual activity of CRL nanogel was 97.3±1.8 %. It was indicated that the novel CRL nanogel was an excellent biocatalyst.

Efficiency of Salen Functionalized Ionic Liquids and their Application towards Biological Activity

Schiff bases were often used as chelating ligands for the stabilization of metal ions with various oxidation states. It is called privileged ligands, due to their own peculiar capacity to make a four and six coordinated salen complex to stabilize the metal ions. On the other hand, Ionic liquid (IL) also plays a key material in engineering and scientific fields. Due to their own physiochemical properties and widespread applications in different areas of research. It has been recently found that, the suitable choice and appropriate size of cation and anion can alter the geometry of ILs and it directly influenced the biological activity of ILs. Herein ionic liquid tagged new salen complexes of first row transition metals such as Fe, Co, Ni, Cu and Zn have been synthesized successfully and characterized. The structure of synthesized salen complexes were studied by UV, FT-IR, NMR and Mass spectroscopic techniques. Metal complexes play a vital role in drug discovery since ancient times. Especially, these complexes can interact with the cell membrane and make the morphological changes in the affected site. Moreover, the efficiency of salen complexes were assessed by antimicrobial and antifungal studies. Among all the IL tagged salen complexes the Ionic liquid tagged cobalt salen complexes was very effective against the tested microorganisms.

Research on Synthesis, Characterization and CO<sub>2</sub> Absorption of Functional Room Temperature Ionic Liquids

Iron and steel making is an industry with high energy consumption and greenhouse gas emissions. The work is to carry out the CO2 capture experimental study as background of the blast furnace gas, increase the calorific value of the blast furnace gas and reduce greenhouse gas emissions and the energy consumption of CO2 gas in the follow-up process cycle. In this paper, according to the principle of acid base neutralization, [EDA]L and [EDA]P contained amino ionic liquids are synthesized in ice water bath condition, which is made from lactic acid, formic acid and ethylenediamine. The synthesis process was explored, the viscosity and infrared spectroscopy of synthetic ionic liquid were characterized, the boiling point of ionic liquids were calculated, CO2 absorption experiments were carried out under normal temperature and pressure. The results indicate that the compositions are ionic liquids having target structures and the maximum molar absorption of ionic liquid to CO2 reaches 0.45 mol.

A novel amphipathic low-melting complex salt: An efficient homogeneous catalyst for synthesis of pyran-annulated heterocyclic scaffolds and pyrido[2,3-d]pyrimidines

Abstract The reaction of triethyl(sulfonyl)ammonium chlorosulfonate with 1,1,3,3-tetramethylguanidine (TMG) gave a low-melting complex salt with amphipathic and acidic characters. The salt has a great tendency towards solvation of organic substrates upon slight heating, so it was employed as a homogeneous acidic and functional ionic liquid catalyst in the expedient synthesis of benzo[b]pyrans, pyrano[4,3-b]pyrans, pyrano[3,2-c]quinolones, and pyrido[2,3-d]pyrimidines. The catalytic activity of the complex salt is much better than the simple salts composing it. Spectroscopic studies and chemical analysis of the salt revealed that its empirical formula is in agreement with neutralization of TMG by two H2SO4 molecules. The HSO4− anions of the salt seem to form extensive H-bonding with the constituting ammonium cations and Cl−, resulting in melting point depression of the complex salt due to the melting points of pure triethylamine and TMG hydrochloride salts. Another significant feature of this solid salt is that it can preserve its composition even after several times of separation from aqueous extracts and can be handled easily without danger.

β-Cyclodextrin-derived Room Temperature Macromolecular Ionic Liquids by PEGylated Anions.

A series of cyclodextrin-derived room temperature macromolecular ionic liquids carrying rather low glass transition temperatures of -20 to -40 °C are synthesized via sequential esterification, quaternization, and anion metathesis reactions. In addition to being ionic in nature, they are viscous liquids at room temperature with more fluidic behavior at elevated temperatures. They serve as a solvent for organic dyes or iodine separation via a liquid-liquid extraction approach. This strategy is useful for the development of various sugar (macro)molecule-based functional ionic liquids as well as macromolecular ionic liquids.

Solvent extraction of lithium from aqueous solution using an ammonium ionic liquid

Abstract A new functionalized ionic liquid (FIL), tetrabutylammonium 2-ethylhexyl hydrogen-2-ethylhexylphosphonate ([N4444][EHEHP]), was prepared and used in the extraction of lithium ion from aqueous solution. The factors affecting the extraction efficiencies, such as aqueous acidity, extractant concentration and temperature, were optimized. The mechanism involved in the extraction system was analyzed by slope analysis and FT-IR data. According to the Van't Hoff equation, the thermodynamic functions of the extraction reaction in ionic liquid system were obtained. Liquid/liquid extraction tests indicated that the ionic liquid system exhibited better selectivity towards lithium ions in the solution containing alkali metal ions. In addition, the quantitative stripping of lithium ions from the loaded ionic liquid phase was carried out and the effect of hydrochloric acid concentration on stripping rate was investigated in detail.

Highly Reversible and Efficient Absorption of Low-Concentration NO by Amino-Acid-Based Ionic Liquids

A series of environmentally benign functional ionic liquids (ILs) based on l-proline as the anion to efficiently absorb low-concentration NO have been investigated in this work. The results indicat...

Research Progress in the Application of Supported Functional Ionic Liquids in Organic Transformations

Research Progress in the Application of Supported Functional Ionic Liquids in Organic Transformations

Mesoporous Carbons Derived from Pyrolysis of Organosilica‐Based Ionogels for Oxygen Reduction Reaction

AbstractDeveloping of novel carbon‐based materials for electrocatalytic oxygen reduction reaction is highly important for sustainable energy conversion. In this work, iron‐containing ionogels were prepared from functional ionic liquid 1‐propionic acid‐2‐methyl imidazole bromide as the linker and an organically‐modified silica framework as the host, which were polymerized in the presence of iron(III) nitrate nonahydrate. The ionogels are mechanically stable, yellowish and transparent. After pyrolysis and washing by acid, unique mesoporous carbon materials were innovatively synthesized. Moreover, the as‐obtained carbon materials possess very high surface areas (1127 m2 g−1), significant mesoporosity and abundant catalytic sites (e. g., effective N configurations). The optimal catalyst exhibits remarkable ORR activity with an onset potential (Eonset) of 0.98 V vs. RHE, a half‐wave potential (E1/2) of 0.823 V vs. RHE and a diffusion‐limited current density (jL) of 5.75 mA cm−2 in 0.1 M KOH, comparable to the commercial Pt/C catalyst in the same condition. This work provided a new strategy to fabricate promising electrocatalyts for application in fuel cells.

Tuning the strength of cation coordination interactions of dual functional ionic liquids for improving CO2 capture performance

A novel strategy for efficient CO2 capture by tuning the strength of cation coordination interactions of alkali metal chelated dual functional ionic liquids (DFILs) is reported. CO2 absorption and viscosity experiment, quantum-mechanical calculations showed that the strengthening of the coordination interactions between alkali metal ions and alkanolamine ligands of DFILs containing imidazolide anion ([Im]−) leads to improve the stability of the cheated cation and weaken the chelated cation-anion interaction, resulting in efficient CO2 capture capacity and reducing the viscosity of DFILs. Particularly, [K(DGA)2][Im] has the stronger cation coordination interactions and lower viscosity (249.8 mPa∙s), exhibiting more efficient CO2 capture capacity than other DFILs, with an extremely high capacity of CO2 (∼1.37 mol/mol) in 15 min at T = 333.2 K under atmospheric pressure and good reversibility (5 recycles). Spectroscopic investigations and quantum-mechanical calculations showed that such high CO2 capacity originates from the fact that both [K(DGA)2]+ and [Im]− of [K(DGA)2][Im] react with CO2. Moreover, [Im]− reacts preferentially with CO2 over [K(DGA)2]+.

The study of hexanoate-based protic ionic liquids used as lubricants in steel-steel contact

Three novel hexanoate-based protic ionic liquids with different ammonium cations (2-hydroxyethylammonium 2-ethylhexanoate, 2-hydroxymethylammonium 2-ethylhexancate, and 2-hydroxydimethylammonium 2-ethylhexanoate) were synthesized, characterized, and studied as neat lubricants under a steel-steel sliding contact mode. The ionic liquid with the 2-hydroxyethylammonium cation presented the highest values of density, viscosity, contact angle and thermal stability. The high value of viscosity and contact angle in the 2-hydroxyethylammonium salt can be attributed to hydrogen bonding. The three protic ionic liquids, especially 2-hydroxyethylammonium 2-ethylhexanocate and 2-hydroxymethylammonium 2-ethylhexanocate, outperformed other studied lubricants showing lower and stable friction coefficient. The improved lubrication performance is attributed to the strong physical adsorption of the ionic liquids on the steel-steel surfaces to form ordered lubrication layers due to the electrostatic interaction. In addition, the formation of carbon- and oxygen-enriched layers on worn steel surfaces helped to reduce friction. The formation of this tribolayer may be due to the high contact temperature and pressure conditions that promote the reaction of the active elements of steel and functional groups ionic liquids.

From gene delivery agents to ionic liquids: The impacts of cation structure and anion identity on liquefaction

Fundamental to the field of ionic liquids is the understanding that structure begets function. In this work, we reported the development of thioether-based ionic liquids, with enhanced hydrophobicity and low melting point (Tm), via the thiol‒yne reaction. Cationic lipids can simply be converted to macroscopically hydrophobic ionic liquids by replacing their native chloride counteranion with Tf2N. Features that specifically increase or decrease fluidity are identified by juxtaposing the wide-ranging Tm values of these highly lipophilic salts with elements of their cation structures. Most importantly, when these Tm-increasing and -decreasing features are incorporated into the same cation, an “averaged” Tm value is observed. These findings may prove to be elements of the “know-how” needed to design functional ionic liquids that liquefy within relatively predictable temperature ranges.

Progress in environmental behaviors and safety of ionic liquids

Ionic liquids are remarkable chemical compounds, which are widely used in catalysis, energy, material preparation, biochemical and pharmaceutical fields due to their non-volatile, non-flammable, designable structure and high stability. In 1914, the first ionic liquid [EtNH3][NO3] was reported, but that was very unstable in the air. With the explosion, the development of ionic liquids has gone through a long period of silence. Subsequently, with the synthesis of chloroaluminate ionic liquids, the development of ionic liquids has become rapid, from imidazole, quaternary ammonium, pyridine-type ionic liquids to currently highly concerned functional ionic liquids. With the mass production and wide application of ionic liquids, their health risks to the environment have also attracted considerable attention. Although ionic liquids are green, stable, non-volatile, and non-flammable, which would not cause atmospheric pollution, they might be exist in soil and water environment in the process of use, such as production, recovery and treatment. In this paper, the structures of ionic liquids were described, and the influence of ionic liquids structure on biological safety was analyzed. The migration and transformation behavior of ionic liquids in different environmental media and the possible influencing factors were discussed. The environmental behavior of ionic liquids in water and soil is a systematic project. Single toxicity data and environmental data cannot objectively evaluate it. At present, a few related safety numbers of ionic liquids are available, and we should pay greater attention to the safety research of toxicity, degradation and corrosiveness directly related to environmental protection. The effects of ionic liquids on microorganisms, aquatic organisms and terrestrial organisms were summarized. There is no uniformity in toxic activities exhibited by ionic liquids. Some of them demonstrate relatively low toxicity, whereas others impose significant inhibitory effects in various biological systems. Several researches have been aimed at finding relationships that link the ionic liquid structure to its toxicity. However, no general correlations have been discovered. According to the accumulated data, the effect factors of toxicity are including the length of alkyl side chain in the cation, the presence and nature of functional groups in the cation, the anion and cation nature; and interactions between anion and cation. Generally, there is a positive relationship between the alkyl side chain length and toxicity, and an inverse relationship between the relative number of oxygen atoms and toxicity. However, the toxicity of ionic liquids does not always comply with the above rules. The current chemical and biological degradation methods of ionic liquids were reviewed. It is necessary to choose safe and effective degradation methods according to the anions and cations of ionic liquids. Ionic liquids with short side chains should choose chemical degradation as far as possible, while ionic liquids with long alkyl side chains should give priority to biodegradation. In addition, the influences of ionic liquids’ structure on their degradation performance need to be systematically studied. In order to provide a basis for the development of low toxicity and biodegradable ionic liquids, it is also an important way to improve the safety of ionic liquids. This paper clarifies that further study on the environmental behavior, safety effects and degradation methods of ionic liquids is of high scientific value, which is great significance for objective evaluation of the potential of large-scale application of ionic liquids.

Mobility boost up of hybrid TFT with solvent-free cross-linked polyurethane-ionic liquid gate dielectric

We proposed solvent-free cross-linked ion gel polymer as a high-κ gate dielectric composed with polyurethane terminated with acrylate functional group and ionic liquids (1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide) through ultra violet curing (UV-cured IL-PU). Free-standing UV-cured IL-PUs were applied as gate insulator by conformally contacting on the amorphous indium gallium zinc oxide side-gate structure thin film transistor with a simple ex situ method. The device shows a dramatic improvement of electrical performances even under low operating voltage conditions; on/off ratio ∼104, field effect mobility at linear region 47.79 ± 17.65 cm2 V−1 s−1, sub-threshold swing 145.54 ± 16.65 mV decade−1 at VDS = 0.1 V and VGS sweep from −3 to 2 V.

Effect of Ionic Composition on Physicochemical Properties of Mono-Ether Functional Ionic Liquids.

Tunable properties prompt the development of different “tailor-made” functional ionic liquids (FILs) for specific tasks. FILs with an ether group are good solvents for many organic compounds and enzymatic reactions. However, ionic composition influences the solubility by affecting the physiochemical properties of these FILs. To address the structure effect, a series of novel FILs with a mono-ether group (ME) based on imidazole were prepared through cationic functionalization and anionic exchange reactions, and characterized by NMR, mass spectroscopy, and Thermogravimetric analysis (TGA). The effect of ionic composition (cationic structure and anions) on density, viscosity, ionic conductivity, electrochemical window, and thermal properties of these ME-FILs were systematically investigated. In general, the viscosity and heat capacity increases with the bigger cationic volume of ME-FILs; in particular, the 2-alkyl substitution of imidazolium enhances the viscosity remarkably, whereas the density and conductivity decrease on the condition of the same [NTf2]− anion; For these ME-FILs with the same cations, the density follows the order of [NTf2]− > [PF6]− > [BF4]−. The viscosity follows the order of [PF6]− > [BF4]− > [NTf2]−. Ion conductivity follows the order of [NTf2]− ≈ [BF4]− > [PF6]−. It is noted that the dynamic density has a good linear relationship with the temperature, and the slopes are the same for all ME-FILs. Furthermore, these ME-FILs have broad electrochemical windows and glass transition temperatures in addition to a cold crystallization and a melt temperature for ME-FIL7. Therefore, the cationic structure and counter anion affect the physicochemical properties of these ME-FILs together.