Evaluating the complexation behavior and regeneration of boron selective glucaminium-based ionic liquids when used as extraction solvents

Glucaminium-based ionic liquids are a new class of solvents capable of extracting boron-species from water with high efficiency. The complexation behavior of these ILs with borate was thoroughly studied using ¹¹B NMR. Two different complexes, namely, monochelate complex and bischelate complex, were observed. ¹¹B NMR was used extensively to determine the formation constants for monochelate and bischelate complexes. The IL concentration was observed to have a significant effect on the IL–borate complexes. Using an in situ dispersive liquid–liquid microextraction (in situ DLLME) method, the extraction efficiency for boron species was increased dramatically when lithium bis[(trifluoromethyl)sulfonyl]imide (LiNTf₂) was used as the metathesis salt in an aqueous solution containing 0.1 M sodium chloride. IL regeneration after extraction was achieved using 0.1 M hydrochloric acid. The extraction efficiency of boron species was consistent when the IL was employed after three regeneration cycles. The selectivity of the IL for boron species in synthetic seawater samples was similar to performing the same extraction from Milli-Q water samples.     

Synthesis of dicationic ionic liquids and their application in the preparation of hierarchical zeolite Beta

Piperidine- and imidazole-based dicatoinic ionic liquids have been developed for the synthesis of zeolite Beta. Hierarchical Beta has a larger surface area and pore volume than conventional Beta. Beta derived from a dicationic ionic liquid exhibited remarkably higher catalytic activity than the conventional Beta. Experimental evidence and DFT calculations suggest that only a suitable conformation of such dicationic ionic liquids is able to form zeolite Beta (see scheme).     

Water electrolysis: an excellent approach for the removal of water from ionic liquids

An electrochemical system based on platinum cathode and glassy carbon anode was assembled for a successful removal of water from ionic liquids via the water electrolysis strategy.     

Synthesis of ricinoleate anion based ionic liquids and their application as green lubricating oil additives

Ricinoleate anion based ionic liquids (ILs) were synthesized from four different nitrogen containing cationic counterparts such as tetrabutylammonium, tetrapropylammonium, cetyltrimethylammonium, imidazolium. Tribological performance of synthesized ILs were evaluated using four ball tribo tester by blending with two lubricant base oils namely epoxy2-ethylhexyl esters of karanja fatty acids (EKE) and dioctyl sebacate (DOS). Antiwear behaviour was explored by varying different factors including concentration, applied load and rotation speed. It was found that the synthesized ILs in base oil significantly reduced the wear scar diameter by 17–25% at 0.8 wt% and a remarkable reduction in wear scar diameter was observed for all the tested applied load (40 to 80 kg) and rotation speed (1200 to 1742 rpm). Further, the load carrying capacity of base oil was improved by 25–43% at 1.25 wt% of IL dosage. The imidazolium cation containing IL outperform tribological performance among all the ILs being studied. The morphology of worn surface after the wear tests and deposition of elementals on the worn surface lubricated with neat base oil and IL blended base oil was studied by scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDX).     

Synthesis and ionic conductivity of polymer ionic liquids

Four vinyl monomers containing a covalently bonded cation ethylimidazolium and various anions—Br^?, (CF₃SO₂)₂N^?, (CN)₂N^?, and CF₃SO ₃ ^? —have been synthesized. High-molecular-mass polymers (M _w up to 1.84 × 10⁶) having the structure of ionic liquids have been prepared via the free-radical polymerization of 1-vinyl-3-ethylimidazolium in bulk and molecular and ionic solvents. The thermal stability and heat resistance of the resulting polymer salts have been estimated. It has been demonstrated that the thermal characteristics of these salts significantly depend on the nature of anions. The glass-transition temperatures of the polymers range from 19 to 235°C. The ionic conductivity of the polymer salts and their compositions with individual ionic liquids has been studied in the frequency range 50–10⁶ Hz. The highest conductivity (1.5 × 10^?5 S/cm) is exhibited by the polymer containing the (CN)₂N^? anion.     

Synthesis of polymeric ionic liquids material and application in CO_2 adsorption

We synthesized one quaternary ammonium polymeric ionic liquids(PILs)P[VBTHEA]Cl and three imidazolium PILs of P[VEIm]Br, P[VEIm]BF_4, P[VEIm]PF_6 by free-radical polymerization in solution. These PILs were characterized by FT-IR,~1 H-NMR,~(13)C-NMR, TGA, XRD and SEM. Their CO_2 adsorption capacities were measured under different pressures and temperatures by constant-volume technique. It was observed that quaternary ammonium PILs of P[VBTHEA]Cl have higher adsorption capacity for CO_2 than those imidazolium PILs, following P[VBTHEA]Cl P[VEIm]PF_6 P[VEIm]BF_4 P[VEIm]Br, which may be ascribed to higher positive charge density on ammonium cation than that on imidazolium cation and thus stronger interaction with CO_2, consistent with the results from dual-mode adsorption model that ammonium PILs have much higher CO_2 bulk absorption than imidazolium PILs. CO_2 adsorption capacity of P[VBTHEA]Cl is 9.02 mg/g under 295 K and 1 bar, which is comparable to that of some other PILs, and is much higher than that of the corresponding ILs monomer. These PILs have good adsorption selectivity for CO_2 over N_2 and regeneration efficiency.     

离子液体的合成及其对瓜尔胶的溶解性能

本文合成了氯化1-烯丙基-2-丙烯基-4,5-二氢化咪唑(AihimCl),氯化1-丁基-2-丙烯基-4,5-二氢化咪唑(BihimCl),氯化1-己基-2-丙烯基-4,5-二氢化咪唑(HihimCl),氯化1-辛基-2-丙烯基-4,5-二氢化咪唑(OihimCl)四种离子液体;并用傅立叶转换红外光谱(FT-IR),核磁共振氢谱(1H NMR)和碳谱(13C NMR)表征了其结构;研究了这四种离子液体对瓜尔胶(GG)的溶解性,并用偏光显微镜观察了其溶解过程,瓜尔胶在BihimCl中的溶解度可达5.5%;比较了瓜尔胶在四种离子液体中的溶解速度,在BihimCl和OihimCl中的溶解速度比在AihimCl和HihimCl中快,6小时后都能够完全溶解。     

Synthesis of new chiral ionic liquids from natural acids and their applications in enantioselective Michael addition

Two kinds of novel chiral ionic liquids based on imidazolium have been synthesized from chiral pool by a simple and straightforward procedure in good overall yields (44-60%). The application of CILs as reaction media in the enantioselective Michael addition of diethyl malonate to 1,3-diphenyl-prop-2-en-1-one has also been studied (yield 90-96%, 10-25% ee).     

Synthesis and properties of ionic liquids derived from the 'chiral pool'

New chiral ionic liquids have been synthesised which are directly derived from the 'chiral pool' and therefore readily available in kg scale; NMR-measurements indicate that these liquids may be interesting solvents for enantioselective reactions and useful in chiral separation techniques.     

Structure of ionic liquids on the basis of imidazole and their mixtures with water

1-Ethyl-3-methylimidazolium acetate absorbs up to 27% of water from air at room temperature with liberation of a large amount of heat, 11 kJ mol⁻¹. Ions of the ionic liquid do not enter into chemical reaction with water but form a stable complex of ethylmethylimidazolium acetate with 12H₂O molecules (EMIA·12H₂O).     

Synthesis of chiral ionic liquids from natural amino acids

For the first time, chiral imidazolium ionic liquids containing one chiral carbon (10a-c) were synthesized from the natural amino acids by a simple and straightforward procedure. The characteristics of the chiral ILs are very similar to the popular ionic liquids.     

Electrospray ionization mass spectrometry of ionic liquids and determination of their solubility in water

Electrospray ionization mass spectrometry is used to detect both the cations (C⁺) and the anions (A^–) of ionic liquids (CA). In this study, the ionic liquids are diluted with aqueous methanol before injection. In addition to the main peaks of the parent ions, fragmentation products are observed upon increasing the cone voltage, whereas aggregates of the parent ion with one or more ionic liquid molecules (e.g., C(CA)_n⁺, A(CA)_n^–) are observed upon decreasing the cone voltage. The ions of several ionic liquids in a mixture are also detected and the ratios of their concentrations estimated. A method is developed to determine quantitatively the concentration of an ionic liquid in solution by using the cation and anion of another ionic liquid as internal standards. By using this method, the solubilities in water at room temperature (22±1 °C) of three typical hydrophobic ionic liquids have been determined: 0.70±0.08 g L^–1 for methyltributylammonium bis(trifluoromethylsulfonyl)imide (MeBu₃NNTf₂), 6.0±0.5 g L^–1 for butylmethylpyrrolidinium bis(trifluoromethylsulfonyl)imide (BuMePyrNTf₂), and 18.6±0.7 g L^–1 for 1-butyl-3-methylimidazolium hexafluorophosphate (BMIPF₆).     

Synthesis of CoPt nanorods in ionic liquids

Cobalt platinum nanorods, hyperbranched nanorods, and nanoparticles were synthesized in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [BMIM][Tf2N], ionic liquid though the thermal reduction of platinum acetylacetonate, and cobalt acetylacetonate at 350 degrees C in the presence of cetyltrimethylammonium bromide (CTAB). It was found that the morphology, composition, and crystal phase of the resultant CoPt alloy nanomaterials could be controlled by changing the concentration and molar ratio of platinum and cobalt reactant precursors.     

Synthesis of fluoromethylated materials in ionic liquids

Syntheses of fluoromethylated materials via Michael additions with the Baylis-Hillman type reaction and the reaction of fluoromethylated imines with enamines in ionic liquid are described.     

Synthesis of novel chiral imidazolium-based ionic liquids derived from isosorbide and their applications in asymmetric aza Diels-Alder reaction

A novel family of chiral imidazolium-based ionic liquids containing a chiral moiety and a free hydroxyl function has been designed and synthesized using isosorbide as a biorenewable substrate. These chiral ionic liquids were found to catalyze the aza Diels-Alder reaction to give good yields and moderate diastereoselectivities. Chiral ionic liquids are recycled while their efficiency is preserved.     

Synthesis of thermoregulated phase-separable triazolium ionic liquids catalysts and application for Stetter reaction

A series of polyether-substituted triazolium ionic liquids catalysts have been first synthesized for resolving the problem of separation and reuse of Stetter catalysts. The catalysts possess the properties of critical solution temperature (CST) and inverse temperature-dependent solubility in toluene/heptane solvents. Based on these properties, the catalysts can achieve the catalytic process named as thermoregulated phase-separable catalysis (TPSC) with the characteristic of homogeneous reaction at higher temperature and phase-separation at lower temperature. The novel TPSC system has been successfully applied for Stetter reaction of furfural or butanal with ethyl acrylate. The experimental results have showed that the novel catalysts exhibit excellent TPSC with high recycling efficiency.     

Phase separation in mixtures of ionic liquids and water

The phase separation of ionic liquids (ILs) in water is studied by laser light scattering (LLS). For the ILs with longer alkyl chains, such as [C(8)mim]BF(4) and [C(6)mim]BF(4) (mim = methylimidazolium), macroscopic phase separation occurs in the mixture with water. LLS also reveals the coexistence of the mesoscopic phase, the size of which is in the order of 100-800 nm. In aqueous mixtures of ILs with shorter alkyl chains, such as [C(4)mim]BF(4), only the mesoscopic phase exists. The mesoscopic phase can be effectively removed by filtration through a 0.22 μm filter. However, it reforms with time and can be enhanced by lowering the temperature, thus indicating that it is controlled by thermodynamics. The degree of mesoscopic phase separation can be used to evaluate the miscibility of ILs with water. This study helps to optimize the applications of ILs in related fields, as well as the recycling of ILs in the presence of water.