Ionic Liquid Salt Research Articles

Convenient and Efficient Method for the Synthesis of Phthalocyanines and Metallophthalocyanines in Task-Specific 2-Hydroxyethyl Ionic Liquids

Tetramerization of substituted phthalonitriles in task-specific 2-hydroxylethyl-based imidazolium and ammonium ionic liquids at 100 °C gave corresponding phthalocyanines in moderate yield. Further the reaction of substituted phthalonitriles in the presence of transition-metal salts in ionic liquids gave the corresponding metallophthalocyanines. The 2-hydroxylethyl ammonium ionic liquids gave better yields of phthalocyanines than 2-hydroxylethyl imidazolium and nonhydroxyl functionalized ionic liquids. The isolation and separations of different phthalocyanines were accomplished by silica-gel column chromatography, and products were characterized by various spectroscopic techniques.

Transport and Electrochemical Properties of Three Quaternary Ammonium Ionic Liquids and Lithium Salts Doping Effects Studied by NMR Spectroscopy

Ionic liquids (IL) composed of a quaternary ammonium cation having an ether chain, N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium (DEME) are electrochemically stable and used in electric double layer capacitors and also one of important candidates to use lithium secondary batteries. In this study, three DEME-based ILs with anions BF4, CF3BF3, and N(SO2CF3)2 were studied by measuring temperature dependences of ionic conductivity σ, viscosity η and density ρ. Also ion diffusion coefficients Danion and Dcation were obtained by NMR spectroscopy in the wide temperature range. Using the classical Stokes–Einstein (SE) and Nernst–Einstein (NE) equations, the relationships between η and D, and σ and D were evaluated. The lithium salt doping effects were studied by 7Li NMR spectroscopy. The lithium ion diffusion was slower than other ion diffusion at every temperature. Arrhenius-type plots of 7Li T1 showed minima in the three doped samples. Then one-jump distance of lithium ion was estimated in the temperature range between 273 and 373 K.

Extractive distillation with the mixture of ionic liquid and solid inorganic salt as entrainers

The use of the mixture of ionic liquid (IL) and solid inorganic salt in place of the single IL as entrainers for extractive distillation, which integrates the advantages of a liquid solvent, that is, IL (easy operation and nonvolatility) and a solid salt (high separation ability) has been proposed in this work. The vapor–liquid equilibrium experiments indicated that the combination of [EMIM]+[Ac]− and KAc is the most promising for the separation of ethanol and water among all of the entrainers investigated. Based on the thermodynamic study, the conceptual process design was developed to evaluate the competitiveness of the suggested entrainers for the separation of ethanol and water. It was determined that the overall heat duty on reboilers in the extractive distillation process using the new mixed entrainers decreases 19.04% compared with the benchmark entrainer [EMIM]+[Ac]−. Moreover, the density functional theory and COSMO‐RS model were used to achieve theoretical insights at the molecular level. © 2014 American Institute of Chemical Engineers AIChE J, 60: 2994–3004, 2014

Direct Synthesis of Nitrogen-Doped Carbon Materials from Protic Ionic Liquids and Protic Salts: Structural and Physicochemical Correlations between Precursor and Carbon

The traditional preparation of carbon materials requires specific polymer precursors and complex procedures. In this work, a series of easily prepared protic ionic liquids and salts (PILs/PSs) based on widely obtainable N-containing bases and acids were synthesized and explored as novel small-molecule precursors for preparing carbon materials via direct carbonization. Protonation enables nearly all N-containing compounds to be directly carbonized to carbon materials without the additional catalyst, tedious synthesis, vacuum system, and etching step that are often involved with conventional precursors. The correlations between the organic precursors and the properties of the carbon materials, in terms of yield, graphitization, N content, thermal stability against oxidation, and porosity, were systematically investigated. Based on the molecular tunability of PILs/PSs, it was possible to obtain task-specific carbon materials through ab initio design of the precursors at the molecular level. Importantly, high...

Copolymer-grafted silica phase from a cation–anion monomer pair for enhanced separation in reversed-phase liquid chromatography

This work reports a new imidazolium and L-alanine derived copolymer-grafted silica stationary phase for ready separation of complex isomers using high-performance liquid chromatography (HPLC). For this purpose, 1-allyl-3-octadecylimidazolium bromide ([AyImC18]Br) and N-acryloyl-L-alanine sodium salt ([AAL]Na) ionic liquids (IL) monomers were synthesized. Subsequently, the bromide counteranion was exchanged with the 2-(acrylamido)propanoate organic counteranion by reacting the [AyImC18]Br with excess [AAL]Na in water. The obtained IL cation-anion monomer pair was then copolymerized on mercaptopropyl-modified silica (Sil-MPS) via a surface-initiated radical chain-transfer reaction. The selective retention behaviors of polycyclic aromatic hydrocarbons (PAHs), including some positional isomers, steroids, and nucleobases were investigated using the newly obtained Sil-poly(ImC18-AAL), and octadecyl silylated silica (ODS) was used as the reference column. Interesting results were obtained for the separation of PAHs, steroids, and nucleobases with the new organic phase. The results showed that the Sil-poly(ImC18-AAL) presented multiple noncovalent interactions, including hydrophobic, π-π, carbonyl-π, and ion-dipole interactions for the separation of PAHs and dipolar compounds. Only pure water was sufficient as the mobile phase for the separation of the nucleobases. Ten nucleosides and bases were separated, using only water as the mobile phase, within a very short time using the Sil-poly(ImC18-AAL), which is otherwise difficult to achieve using conventional hydrophobic columns such as ODS. The combination of electrostatic and hydrophobic interactions are important for the effective separation of such basic compounds without the use of any organic additive as the eluent on the Sil-poly(ImC18-AAL) column.

Electrolytes for lithium and lithium ion batteries: From synthesis of novel lithium borates and ionic liquids to development of novel measurement methods

Abstract This review covers various aspects of electrolyte investigations. The first section reports on synthesis and characterization of lithium salts and ionic liquids, including some unpublished recent work. The next part is devoted to transference number measurements of lithium ions. It contains recently published work and new results on this rarely investigated but important topic. Studies of anodic aluminum dissolution with our novel fast impedance scanning electrochemical quartz microbalance (FIS-EQCM) follow next. After a short introduction to the method, some recently published results are reviewed along with some yet unpublished material. We have also shown that the solubility of solids and gases in liquids can be measured with this equipment, including the solubility of lithium salts in ionic liquids. First results of FIS-EQCM studies show that electroplating and corrosion of lithium and subsequent dissolution of the SEI can be studied as well. The last parts of this manuscript are dedicated to the investigation of miscellaneous topics that are of interest for studies of electrolytes for LIBs.

Chitosan-Based Polymer Electrolyte Containing an Ionic Liquid and Inorganic Salt

: Electrochemical energy storage systems (e.g. batteries and supercapacitors) have a vital role in the applications of many portable electronics, medical equipment, electric vehicles, military devices, and renewable energy [1]. The advancements in these technologies, increase the demand for electrochemical energy systems to achieve higher levels of performance [2]. The development of these high-performance systems have proven extremely difficult because of the need to simultaneously satisfy multiple battery performance requirements such as high energy, high power, long cycle life, low-cost, wide temperature range, safety, minimal impact to the environment, and flexibility to meet various design needs [3,4].Currently, conventional electrochemical storage systems suffer from serious problems such as leakage, toxicity, and high-cost disposal, resulting in unsuitable long-term sustainability [1]. Solid polymer electrolytes have attracted considerable attention for their potential in electrochemical devices due to their light weight, thermal stability, reduced risk of leakage, and flexibility [4]. These systems are mainly comprised of a crosslinked network between a polymer, an organic liquid (e.g. ethylene carbonate, propylene carbonate, diethyl carbonate, etc.), and lithium based salt [5].In this study, a gel electrolyte consisting of the host polymer, chitosan, has been synthesized to compare the crosslinking components, acetic acid and adipic acid. The films were incorporated with an ionic liquid and inorganic salt (LiCl) to increase ionic conductivity. FT-IR plots were compared to determine possible cross-linking mechanisms. Thermal analysis and AC impedeance data were obtained to determine the effect of the crosslinker, as well as the concentration of salt on the thermal stability and ionic conductivity of the gel samples.

An imidazolium-based polymerized ionic liquid via novel synthetic strategy as polymer electrolytes for lithium ion batteries

An imidazolium-based polymerized ionic liquid (PIL), poly(1-ethyl-3-vinylimidazolium bis(trifluoromethanesulfonylimide)) is successfully synthesized via a new three-step process comprising the direct radical polymerization of the 1-vinylimidazole monomer, and subsequent quaternization reaction followed by an anion exchange procedure. Furthermore, polymer electrolytes are prepared by blending as-obtained PIL as the polymer host with an ionic liquid and LiTFSI salt. Electrochemical measurements demonstrate that compared with polymer electrolytes containing the PIL host synthesized by the conventional route, polymer electrolytes containing the PIL host obtained by new synthetic process exhibit significantly improved capacity and cycling performance, which is due to higher ionic liquid content.

Study on Duel Photo-Curing Properties of Quaternary Ammonium Salt Ionic Liquid as Photobase Generator

Two quaternary ammonium tetraphenyl borates salt photobase generators were synthesized using 2-naphthoymethylene as chromophores, and triethylene diamine, pyridine. Their UV curing properties were studied in different environment. The results showed that their photolysis kinetics was of the first order reaction. Quaternary ammonium salts with the UV irradiation can initiate free radical photopolmerization and cure the epoxy resin.

Study on the Physicochemical Properties of the Mixture of Water and 1-butyl-3-methylimidazolium Hydrogen Sulfate Salt Ionic Liquids

The density, viscosity, conductivity of the mixture of 1-butyl-3-methylimidazolium hydrogen sulfate salt ([Bmim]HSO4) ionic liquids and water have been determined at 25°C and atmospheric pressure. It was found that the density and conductivity of [Bmim]HSO4/water increase with the increase the water concentration at the same temperature, whereas the viscosity of [Bmim]HSO4/water decreases. The relationship between conductivities and temperature are agreed well with the Arrhenius equation.

Microwave-Assisted Construction of Nanostructured Poly(amide-imide)s Containing Environmentally Friendly Natural Amino Acids via Implementation of Molten Salt Ionic Liquid as an Activating Media

Within this research, microwave-assisted preparation of chiral nanostructured poly(amide-imide)s (PAI)s, from 5-(2-benzimidazole)-1,3-phenylenediamine (VIII) and various optically active and environmentally friendly diacids, such as N-trimellitylimido-S-valine (IVa), N-trimellitylimido-L-leucine (IVb), N-trimellitylimido-L-alanine (IVc) and N-trimellitylimido-L-isoleucine (IVd) via implementation of molten salt ionic liquid and triphenyl phosphite as an activating media, are demonstrated. The morphology study of the aforementioned polymers shows that these polymers are nanostructured particles and thus are good candidates as carriers for biomedical applications. The sonication of these polymer samples created smaller sizes of the polymer nanoparticles.

Electroreduction of Copper Dichloride Powder to Copper Nanoparticles in an Ionic Liquid

There were a large number of ionic liquids electrodeposition reported in the literature; but were still in the laboratory stage some problems in the practical application of electrodeposition remain such as easily reacted with moisture in the air (AlCl3 ionic liquid), high cost, and corrosive (dialkylimidazolium cation and , ionic liquid). In addition to the above shortcomings, low solubility of many metal salts in ionic liquids limits the practical application. In order to solve the problem of low solubility, [Bmim]Cl could be added [Bmim]PF6, which could significantly increase the solubility of metal chlorides; this method could be commonly used in preparing metal electrochemical reduction of metal chlorides. Our study showed that adding cationic groups in hydroxyl ionic liquid could cause the good solubility of transition metal chlorides, such as CuCl2. Complexation of hydroxyl functional group and transition metal ions increased solubility, resulting in a larger deposition current density and surface electrochemical reduction of copper nanoparticles deposited on the metal Ni. The electroreduction mechanism and behavior of CuCl2 in hydroxyl ionic liquid and the Cu nanoparticle formation mechanism were investigated based on a comparison between similar experiments in the ionic liquid.

Mixing ionic liquids – “simple mixtures” or “double salts”?

In the third issue of the then new journal Green Chemistry (2001, 3, 156–164), we published our first paper describing the physical properties of a few hydrophilic and hydrophobic ionic liquids (ILs) representing one of the first such studies to be published. To help celebrate the 15th anniversary of the Journal, we revisit the ‘design’ aspect of ILs by reviewing the growing area of what most are calling ‘ionic liquid mixtures’. In 2001, designing IL properties meant essentially independent variation or synthesis of the cations and anions and determining what physical or chemical properties these liquid salts possessed. Recently, however, the mixing of ILs has been proposed and investigated as a way to add increased scope to the accessible properties of IL media. In this review, we question whether the same thinking and approach used for organic solvent mixtures should be applied to ILs simply because of the way they were made. Unlike organic solvent mixtures, IL compositions of varied ions, do not retain their individual nature, need not be made by simple mixing of two-ion salts, and preferential interactions of a given cation for a given anion are possible in these 3-ion, 4-ion, or higher order liquids. When two ILs are mixed together, one can't identify which ion is from which IL, and the chemistry is simply not based on the identity of the individual ILs, but on the ions comprising them and the interactions of each individual ion, independently of the counterion. Thus, we ask if it would not be better to consider these as unique ion combinations whose solvent properties are derived from the specific choice and abundance of each ion in the system. Through this review of the available literature, we support the concept of Double Salt Ionic Liquids (DSILs) and discuss the interactions involved in these systems, by examining their physicochemical properties and the novel applications they offer.

(Liquid + liquid) equilibria and extraction capacity of (imidazolium ionic liquids + potassium tartrate) aqueous two-phase systems

To explore the large range of aqueous two-phase system (ATPS) applications, ionic liquid (IL) and organic salt have been recently reported to be able to form ATPS. They could thus be interesting media in biotechnological applications for the separation and purification of biomolecules. In this work, phase diagrams and tie-lines for the 1-butyl-3-methylimidazolium chloride ([C4mim]Cl)/1-hexyl-3-methylimidazolium chloride ([C6mim]Cl)/1-benzyl-3-methylimidazolium chloride ([C7H7mim]Cl)-K2C4H4O6 ILATPSs at 298.15K were measured and presented. It is shown that the larger the cation alkyl chain is, the greater is the IL's ability for ATPS formation, meanwhile the slope of tie-line increases with the increase of cation alkyl chain length. In addition, the extraction capacity of the studied ILATPSs was evaluated through their application to the extraction of chloramphenicol. The partition coefficient of CAP obtained in the IL-K2C4H4O6 ILATPS is followed in the order: [C6mim]Cl>[C4mim]Cl>[C7H7mim]Cl. Moreover, the CAP easily enters the top phase with the increase of temperature of the systems and initial concentration of the solute.

ChemInform Abstract: Facile Synthesis of Benzotriazole Derivatives Using Nanoparticles of Organosilane‐Based Nitrite Ionic Liquid Immobilized on Silica and Two Room‐Temperature Nitrite Ionic Liquids.

AbstractThe room‐temperature task‐specific nitrite ionic liquids SPIN and salts (III) are found to be effective nitrosonium sources for the preparation of benzotriazole derivatives (II) from 1,2‐diaminobenzene derivatives.

Phase diagrams of ionic liquids-based aqueous biphasic systems as a platform for extraction processes

In the past few years, ionic liquid-based aqueous biphasic systems have become the subject of considerable interest as a promising technique for the extraction and purification of several macro/biomolecules. Aiming at developing guidelines for more benign and efficient extraction processes, phase diagrams for aqueous biphasic systems composed of ionic liquids and inorganic/organic salts are here reported. Several combinations of ionic liquid families (imidazolium, pyridinium, phosphonium, quaternary ammonium and cholinium) and salts [potassium phosphate buffer (KH2PO4/K2HPO4 at pH 7), potassium citrate buffer (C6H5K3O7/C6H8O7 at pH 5, 6, 7 and 8) and potassium carbonate (K2CO3 at pH ∼13)] were evaluated to highlight the influence of the ionic liquid structure (cation core, anion and alkyl chain length), the pH and the salt nature on the formation of aqueous biphasic systems. The binodal curves and respective tie-lines reported for these systems were experimentally determined at (298±1)K. In general, the ability to promote the aqueous biphasic systems formation increases with the pH and alkyl chain length. While the influence of the cation core and anion nature of the ionic liquids on their ability to form aqueous biphasic systems closely correlates with ionic liquids capacity to be hydrated by water, the effect of the different salts depends of the ionic liquid nature and salt valency.

Catalytic performance of ion-exchanged montmorillonite with quaternary ammonium salts for the glycerolysis of urea

Various quaternary ammonium salt (QX) ionic liquids immobilized onto montmorillonite clay (Q-MMT) were prepared by ion-exchange reaction between the tetra-alkyl ammonium salts and ions in the clay interlayer. The Q-MMTs were characterized by elemental analyses, nitrogen adsorption–desorption, XRD, 13C and 27Al NMR, TGA, FT-IR, and HRTEM. The d-spacing of the Q-MMTs increased with increasing alkyl chain lengths, however, the surface areas decreased by immobilizing QX onto MMTs. The Q-MMTs showed good catalytic activity for the synthesis of glycerol carbonate from glycerol and urea. The effects of the ionic liquid cation structure, and reaction parameters, such as temperature and degree of vacuum, on the performance of Q-MMTs were also discussed. The catalyst could be reused in up to four consecutive runs without any considerable loss of activity.

SO2 absorption in acid salt ionic liquids/sulfolane binary mixtures: Experimental study and thermodynamic analysis

Two new simple acid salt ionic liquids (ASILs), tetraethylammonium diglutarate ([N2222][diglutarate]) and dimethylethanolammonium diglutarate ([DMEA][diglutarate]) were synthesized and the ASILs/sulfolane binary mixtures containing 40wt% ASILs were prepared for SO2 absorption in this work. The SO2 absorption rate is found to be quite fast with an equilibrium time within 2min, due to the low viscosity of the mixtures. The solubilities of SO2 in the two binary mixtures were measured under the pressure range of 0–1bar and the temperature range of 303.15–333.15K and results demonstrate the binary mixtures could trap as much as 6.836–7.624mol SO2/kg absorbents at 1bar and 303.15K. The solubilities are 0.826–0.954mol SO2/kg absorbents at a pressure as low as 0.004bar, which is important for capturing SO2 from the flue gas with low content of SO2. Thermodynamic analysis based on a Reaction Equilibrium Thermodynamic Model (RETM) was used to calculate the Henry’s law constants, reaction equilibrium constants, chemical absorption capacity, physical absorption capacity and thermodynamic functions of SO2 absorption in the mixtures. The calculated absorption enthalpy are −53.73 and −47.15kJ/mol for the two binary mixtures, respectively. The ASILs/sulfolane binary mixtures are shown to be an attractive alternative to pure ILs to be applied in SO2 absorption due to the large absorption capacity and low absorption enthalpy, as well as the fast absorption rate.

Ionic Liquid Functionalized Graphene‐Based Electrochemical Biosensor for Simultaneous Determination of Dopamine and Uric Acid in the Presence of Ascorbic Acid

AbstractAn electrochemical biosensor for the simultaneous determination of dopamine (DA) and uric acid (UA) in the presence of ascorbic acid (AA) was developed using a glassy carbon electrode modified with 1‐butyl‐3‐methylimidazolium 2‐amino‐3‐mercaptopropionic acid salt ionic liquid functionalized graphene (ILG/GCE). The ILG/GCE possessed excellent electrocatalytic activity toward the oxidation of AA, DA and UA. The separations of oxidation peak potentials of AADA, DAUA, and AAUA were 147, 145 and 292 mV, respectively. The electrochemical sensor showed excellent selectivity and stability and was applied successfully to the determination of DA and UA in real urine samples using the standard addition method with recoveries of 97.0–103.8 %.

Ionic Liquid Tributyl (Carboxymethyl) Phosphonium Bromide as an efficient Catalyst for the Synthesis of bis(indolyl)Methanes under Solvent-Free Conditions

A simple green synthesis of bis (indolyl)methanes involved the reaction of indole with aldehydes in the presence of a phosphonium salt ionic liquid as the catalyst. The simple experimental procedur...