Dissolution of Konjac Glucomannan with Room Temperature Ionic Liquids

Two kinds of new room temperature ionic liquids （RTILs）, 1-allyl-3-methylimidazolium chloride （AMIMCl） and 1-butyl-3-methylimidazolium chloride （BMIMCl）, were synthesized and used for the dissolution of konjac glucomannan （KGM）. The experimental results showed that the solubility of KGM in AMIMCl was better than that in BMIMCl. Regenerated KGM were obtained by adding anhydrous alcohol to the KGM / ionic liquids solutions. Solubility, molecular weight, structure, and thermal property of the regenerated KGM were investigated by polarized optical microscopy （POM）, viscosimetry, infrared spectroscopy （IR）, X-ray diffraction technique （XRD）, thermogravimetry （TG） and differential scanning calorimetry （DSC）. It was demonstrated that the viscosity-averaged molecular weight of the KGM samples decreased after regeneration because of the molecular degradation of KGM. Results from IR and XRD indicated that the chemical structure and the crystalline form of regenerated KGM were not changed. Results from TG and DSC showed that the thermal stability of the regenerated KGM samples only slightly decreased. These results suggest that AMIMCl and BMIMCl are direct and effective solvents for KGM.

Substitution Reactions by Azide and Thiocyanide Anions in Room Temperature Ionic Liquids

Conducted in the ionic liquids, activated and inactivated halides, acyl chlorides, tosylate, and bezotriazolyl acylates were converted to corresponding azide and thiocyanide compounds in high yields under mild conditions.

Benzoin Condensation in Imidazolium Based Room-temperature Ionic Liquids

Benzoin condensation promoted efficiently in three imidazolium based room tempera- ture ionic liquids [bmim]Br, [bmim]BF4 and [Bnmim]BF4 is reported for the first time. Benzoins were obtained in up to 91% yield within less than 30 min under mild conditions.

Synthesis of multi-hydroxyl and sulfonyl dual-functionalized room temperature ionic liquids

Starting from the hydroxylamine (dimethyl amino ethanol, triethanolamine) and 1,3-propane sultone, a series of hydroxyl and sulfonyl dual-functionalized zwitterionic salts and corresponding acidic room temperature ionic liquids have been synthesized. The hydroxyl groups of the synthesized substances were confirmed by the 1H NMR measurement. These zwitterionic salts and ionic liquids may be used for synthesizing other functionalized ionic liquids or ionic liquid-polymer (polyelectrolyte).

Molecular dynamics study of room temperature ionic liquids with water at mica surface

Water in room temperature ionic liquids(RTILs) could impose significant effects on their interfacial properties at a charged surface. Although the interfaces between RTILs and mica surfaces exhibit rich microstructure, the influence of water content on such interfaces is little understood,in particular, considering the fact that RTILs are always associated with water due to their hygroscopicity. In this work, we studied how different types of RTILs and different amounts of water molecules affect the RTIL-mica interfaces, especially the water distribution at mica surfaces,using molecular dynamics(MD) simulation. MD results showed that(1) there is more water and a thicker water layer adsorbed on the mica surface as the water content increases, and correspondingly the average location of K^+ ions is farther from mica surface;(2) more water accumulated at the interface with the hydrophobic [Emim][TFSI] than in case of the hydrophilic [Emim][BF4] due to the respective RTIL hydrophobicity and ion size. A similar trend was also observed in the hydrogen bonds formed between water molecules. Moreover, the 2D number density map of adsorbed water revealed that the high-density areas of water seem to be related to K^+ ions and silicon/aluminum atoms on mica surface. These results are of great importance to understand the effects of hydrophobicity/hydrophicility of RTIL and water on the interfacial microstructure at electrified surfaces.

Effects of water on the structure and transport properties of room temperature ionic liquids and concentrated electrolyte solutions

Transport properties and the associated structural heterogeneity of room temperature aqueous ionic liquids and especially of super-concentrated electrolyte aqueous solutions have received increasing attention,due to their potential application in ionic battery.This paper briefly reviews the results reported mainly since 2010 about the liquid-liquid separation,aggregation of polar and apolar domains in neat RTILs,and solvent clusters and 3D networks chiefly constructed by anions in super-concentrated electrolyte solutions.At the same time,the dominating effect of desolvation process of metal ions at electrode/electrolyte interface upon the transport of metal ions is stressed.This paper also presents the current understanding of how water affects the anion-cation interaction,structural heterogeneities,the structure of primary coordination sheath of metal ions and consequently their transport properties in free water-poor electrolytes.

Impedance Spectroscopic Study on Room Temperature Ionic Liquid-Water Mixtures

AC impedance spectroscopy in pure room temperature ionic liquids （RTILs） and RTIL-water mixture was measured at the temperature of range from 30 ℃ down to -30 ℃. The cations of RTILs are N,N-diethyl-N-methyl-N-（2-methoxyethyl） ammonium （[DEME]）, 1-ethyl-3-methylimidazolium （[C2mim]） and l-butyl-3-methylimidazolium （[Camim]）, the anions are tetrafluoroborate （[BF4]） and bis（trifluoromethanesulfonyl）imide （[TFSI]）. In all pure RTILs, there are two kinds of local minima in real part of the AC impedance Zreal. By adding water to [DEME][BF4] （0 mol% 〈 x 〈 94 mol%） at room temperature, the local minimum value at higher frequency decreased remarkably at the fixed frequency with increasing water concentration. Above 94 mol% H20, a quite different profile of the AC impedance spectroscopy was obtained. In addition to Zreal. temperature dependence of an imaginary part of the impedance Zimag had an isosbestic point below 94 mol%. The isosbestic point disappeared above 94 mol%. The isosbestic point in Zing reveals an interaction between [DEME][BFa] and H2O.

CO2 Capture at Room Temperature and Ambient Pressure: Isomer Effect in Room Temperature Ionic Liquid/Propanol Solutions

A CO2 capture system without supercritical CO2 was optimized for mixtures of hydrophobic room temperature ionic liquids (RTILs) and propanol. We tested RTILs using bis(trifluoromethanesulfonyl)imide, TFSI-, anion and four quaternary ammonium cations, two quaternary phosphonium cations, and one imidazolium cation. The addition of 2-propanol into the RTILs clearly promoted the capture of normal CO2(nCO2) at ambient temperature and pressure. When combined with 2-propanol, the most efficient RTILs for nCO2 capture were N-butyl-N,N,N-trimethylammonium TFSI-. This enhancement of nCO2 capture was not observed in RTIL mixtures with 1-propanol or in propanol mixtures containing other phosphonium- and imidazolium-based RTILs. The torsion angle of TFSI-, which was calculated using density functional theory, is thought to be related to high nCO2 capture efficiently.

Pd(OAc)_2/Cu(OTf)_2在离子液体BMImPF_6中催化苯乙烯二聚反应的研究

在离子液体BMImPF6中,用不同的钯催化剂和Lewis酸三氟甲磺酸铜Cu(OTf)2共催化苯乙烯二聚反应,发现用Pd(OAc)2/Cu(OTf)2作催化剂,Pd/Cu物质的量之比为1～4时,可高产率高选择性地获得苯乙烯二聚产物1,3-二苯基-1-丁烯.BMImPF6对催化剂有较好的溶解性,可固定催化剂体系,使催化剂有效地与产品分离.同时,α-甲基苯乙烯的二聚反应表明,室温下不发生反应,提高温度有利于反应进行.

Synthesis of 2-Arylimidazo[l, 2-a]pyrimidines in Ionic Liquids

Room temperature ionic liquids were used as a "green" recyclable alternative to conventional solvents in the synthesis of pharmaceutically useful compounds 2-arylimidazo[1, 2-a] pyrimidines through Tschotschibabin reaction of a-bromoacetophenones with 2-aminopyrimidine in good yields.

Microwave-Assisted Preparation of CdS Nanoparticles in a Halide-Free Ionic Liquid and Their Photocatalytic Activities

A microwave-assisted (4-6 min) method was used for the preparation of CdS nanoparticles in 1-ethyl-3-methylimidazolium ethyl sulfate,a halide-free room-temperature ionic liquid (RTIL).The samples were characterized by powder X-ray diffraction,energy dispersive X-ray spectroscopy,and scanning electron microscopy.Diffuse reflectance spectra showed a 1.33 eV blue shift relative to bulk CdS.The photocatalytic activities of the nanoparticles for photodegradation of methylene blue (MB) using UV and visible light were measured.The photodegradation of MB decreased with calcination temperature.First order rate constants for the reaction under visible and UV irradiations over the nanoparticles prepared in the RTIL rich media were 5.4 and 2.5 higher,respectively,than the sample prepared in water.

Metal organic framework‐ionic liquid hybrid catalysts for the selective electrochemical reduction of CO_(2) to CH4

The electrochemical reduction of CO_(2) towards hydrocarbons is a promising technology that can utilize CO_(2) and prevent its atmospheric accumulation while simultaneously storing renewable en‐ergy.However,current CO_(2) electrolyzers remain impractical on a large scale due to the low current densities and faradaic efficiencies(FE)on various electrocatalysts.In this study,hybrid HKUST‐1 metal‐organic framework‒fluorinated imidazolium‐based room temperature ionic liquid(RTIL)electrocatalysts are designed to selectively reduce CO_(2) to CH_(4).An impressive FE of 65.5%towards CH_(4) at-1.13 V is achieved for the HKUST‐1/[BMIM][PF_(6)]hybrid,with a stable FE greater than 50%maintained for at least 9 h in an H‐cell.The observed improvements are attributed to the increased local CO_(2) concentration and the improved CO_(2)‐to‐CH_(4) thermodynamics in the presence of the RTIL molecules adsorbed on the HKUST‐1‐derived Cu clusters.These findings offer a novel approach of immobilizing RTIL co‐catalysts within porous frameworks for CO_(2) electroreduction applications.

Effect of ionic liquids on stability of O/W miniemulsion for application of low emission coating products

Room temperature ionic liquids(RTILs) are non-volatile organic salts. They may replace conventional coalescing agents in latex coating thus reducing volatile organic compounds(VOCs) emission as well as improving performance of latex coating products such as better thermal stability, conductivity, and antifouling property. The formation of latex coating containing RTILs can be achieved by encapsulation of RTILs inside particles via miniemulsion polymerization. In this study, the role of RTILs and its concentration on stability of miniemulsion during storage and polymerization were investigated. It has been found that, above a critical concentration(10 wt%), adding more RTILs to oil phase may weaken miniemulsion stability during storage as well as polymerization. Such observations were consistent with the zeta potential measurement for miniemulsions prepared at the similar conditions. The results obtained here would be a useful guideline for the development of new waterborne coating products with desirable functions and particle sizes.

Molecular simulation study of dynamical properties of room temperature ionic liquids with carbon pieces

Room temperature ionic liquids(RTILs) with dispersed carbon pieces exhibit distinctive physiochemical properties. To explore the molecular mechanism, RTILs/carbon pieces mixture was investigated by molecular dynamics(MD) simulation in this work. Rigid and flexible carbon pieces in the form of graphene with different thicknesses and carbon nanotubes in different sizes were dispersed in a representative RTIL 1-butyl-3-methyl-imidazolium dicyanamide([Bmim][DCA]). This study demonstrated that the diffusion coefficients of RTILs in the presence of flexible carbons are similar to those of bulk RTILs at varying temperatures, which is in contrast to the decreased diffusion of RTILs in the presence of rigid carbons. In addition, interfacial ion number density at rigid carbon surfaces was higher than that at flexible ones, which is correlated with the accessible external surface area of carbon pieces. The life time of cation-anion pair in the presence of carbon pieces also exhibited a dependence on carbon flexibility. RTILs with dispersed rigid carbon pieces showed longer ion pair life time than those with flexible ones, in consistence with the observation in diffusion coefficients. This work highlights the necessity of including the carbon flexibility when performing MD simulation of RTILs in the presence of dispersed carbon pieces in order to obtain the reliable dynamical and interfacial structural properties.

Direct Electrochemistry and Electrocatalysis of Hemoglobin Based on Nation-Room Temperature Ionic Liquids- Multiwalled Carbon Nanotubes Composite Film

A robust and effective composite film combined the benefits of Nation, room temperature ionic liquid （RTIL） and multi-wall carbon nanotubes （MWNTs） was prepared. Hemoglobin （Hb） was successfully immobilized on glassy carbon electrode surface by entrapping in the composite film. Direct electrochemistry and electrocatalysis of immobilized Hb were investigated in detail. A pair of well-defined and quasi-reversible redox peaks of Hb was obtained in 0.10 mol,L^-1 pH 7.0 phosphate buffer solution （PBS）, indicating that the Nafion-RTIL-MWNTs film showed an obvious promotion for the direct electron transfer between Hb and the underlying electrode. The immobilized Hb exhibited an excellent electrocatalytic activity towards the reduction of H2O2. The catalysis current was linear to H2O2 concentration in the range of 2.0× 10^-6 to 2.5× 10-4mol·L-1, with a detection limit of 8.0× 10-7 moloL-1 （S/N=3）. The apparent Michaelis-Menten constant （ Kapp ） was calculated to be 0.34 mmolo·L^-1 Moreover the modified electrode displayed a good stability and reproducibility. Based on the composite film, a third-generation reagentless biosensor could be constructed for the determination of H2O2.

Room-Temperature Suzuki-Miyaura Reaction Catalyzed by Palladium Nanoparticles in Lactate-Anion Ionic Liquid

A palladium nanoparticle catalyst(PdNPs@[Bmim]Lac)has been prepared by a simple,mild and efficient chemical approach using 1-butyl-3-methylimidazolium lactate([Bmim]Lac)ionic liquid)as a stabilizer.This catalyst exhibits excellent activity,stability,recyclability and simple manipulation in Suzuki-Miyaura reactions at room temperature in air.

Enhanced refolding of lysozyme with imidazolium-based room temperature ionic liquids: Effect of hydrophobicity and sulfur residue

The expression of recombinant proteins in microorganism frequently leads to the formation of insoluble aggregates, inclusion bodies （IBs）. Thus, the additional in vitro protein refolding process is required to convert inactive IBs into water-soluble active proteins. This study investigated the effect of sulfur residue and hydrophobicity of imidazolium-based room temperature ionic liquids （RTILs） on the refolding of lysozyme as a model protein in the batch dilution method which is the most commonly used refolding method. When lysozyme was refolded in the refolding buffer containing [BF4]-based RTILs with a systematic variety of alkyl chain on cations varying from two to eight, less hydrophobic imidazolium cations having shorter alkyl chains were effective to facilitate lysozyme refolding. Compared to the conventional refolding buffer, 2 times higher lysozyme re- folding yield was obtained in l-ethyl-3-methylimidazolium tetrafluoroborate （[EMIM][BF4]） containing refolding buffer. The refolding yield of lysozyme was even more increased by 2.5 times when 1-butyl-3-methylimidazolium methylsulfate （[BMIM][MS]） containing sulfur residue on anion was used. The sulfur residue in [BMIM][MS] is supposed to improve the refolding yield of lysozyme which has 4 intrarnolecular disulfide bonds. For dilution-based refolding of lysozyme, the opti- mum concentrations of RTILs in refolding buffer were found to be 1.0 M [EMIM][BF4] and 0.5 M [PMIM][MS], respectively. The optimum temperate for dilution-based refolding of lysozyme with RTILs was 4 ℃.

Electrochemical properties of room temperature ionic liquids incorporating BF_4^- and TFSI^- anions as green electrolytes

Two series of room temperature ionic liquids, 1-alkyl-3-methylimidazolium tetrafluoroborate and 1-alkyl- 3-methylimidazolium bis(trifluoromethylsulfonyl)imide (n = 2―4) as electrolytes were prepared and fundamental elec-trochemical properties of the neat ionic liquids and those mixed with an organic solvent (EC-DMC-DEC, 1:1:1, mass ratio) were investigated. It was found that the Arrhenius equation is approximately fit for the relationship between conductivity and temperature for neat ionic liquids within lower temperature range (298―323 K). The VTF interpreta-tion describes the conductivity temperature dependence for the ionic liquids containing tetrafluoroborate anion more accurately than those containing bis(trifluoromethylsulfon- yl)imide anion within wider temperature range. The poten-tial windows are approximately 4.0 V for all these ionic liq-uids. Conductivities of the mixed electrolytes show a maxi-mum value as the solution concentrations increase.

Electrocatalysis Oxidation of GMP Based on Layered Double Hydroxide Functionalized with Anionic Surfactant and Room Temperature Ionic Liquid Modified Glassy Carbon Electrode

The electrocatalysis oxidation of guanosine-5＇-monophosphate （GMP） was investigated on Mg-AI layered double hydroxide （LDH） functionalized with sodium dodecyl sulfate （SDS） and room temperature ionic liquid （RTIL） modified glass carbon electrode （GCE）. The cyclic voltammogram of GMP on the modified electrode （RTIL/ LDH-SDS/GCE） exhibited a well defined anodic peak at 1.091 V in 0.2 moloL ^-1 pH 4.4 acetate buffer solution. The GMP oxidation was enhanced in the presence of anionic surfactant in the films. The results suggest that the surfactant molecules intercalate the LDH layers to preconcentrate GMP molecules and the RTIL showed good ionic conductivity. The experimental parameters were optimized, the kinetic parameters were investigated and the probable oxidation mechanism was proposed. Under the optimized conditions, the oxidation peak current was proportional to GMP concentration in the range from 5.0 × 10^-7 to 1.0×10^-4 mol·L ^-1with the correlation coefficient of 0.9987 and the detection limit was 1.0 × 10 7 mol·L^-1, The RTIL/LDH-SDS/GCE showed a good electrochemical response to the oxidation of GMP and would be developed into a new biosensor.

Immobilization and Bioelectrochemistry of Hemoglobin Based on Carrageenan and Room Temperature Ionic Liquid Composite Film

A novel biopolymer/room-temperature ionic liquid composite film based on carrageenan, room temperature ionic liquid （IL） [1-butyl-3-methylimidazolium tetrafluoroborate （[BMIM]BF4）] was explored for immobilization of hemoglobin （Hb） and construction of biosensor. Direct electrochemistry and electrocatalytic behaviors of Hb entrapped in the IL-carrageenan composite film on the surface of glassy carbon electrode （GCE） were investigated. UV-vis spectroscopy demonstrated that Hb in the IL-carrageenan composite film could retain its native secondary structure. A pair of well-defined redox peaks of Hb was obtained at the Hb-IL-carrageenan composite film modified electrode through direct electron transfer between the protein and the underlying electrode. The heterogeneous electron transfer rate constant （ks） was 2.02 s 1, indicating great facilitation of the electron transfer between Hb and IL-carrageenan composite film modified electrode. The modified electrode showed excellent electrocatalytic activity toward reduction of hydrogen peroxide with a linear range of 5.0 × 10-6 to 1.5 ×10-4 mol/L and the detection limit was 2.12 ×10 7 mol/L （S/N= 3）. The apparent Michaelis-Menten constant KM^app for hydrogen peroxide was estimated to be 0.02 mmol/L, indicating that the biosensor possessed high affinity to hydrogen peroxide. In addition, the proposed biosensor showed good reproducibility and stability.