Synthesis,Characterization, Thermal Analyses,and Spectroscopic Properties of Novel Naphthyl-Functionalized Imidazolium Ionic Liquids

A series of novel ionic liquids based on naphthyl-functionalized imidazolium cation have been prepared. Their structure was characterized by NMR. The thermal stabilities of the prepared liquids were studied by thermal gravimetric analysis. The new ionic liquids containing NTf^-₂ anion display significantly higher thermal stabilities (>400°C). Anion exchange to PF^-₆, BF^-₄, and Br^– decreases the thermal stabilities of such ionic liquids. Fluorescence and UV–Vis absorption spectroscopy were used to study the spectroscopic properties of the ionic liquids. Compared with common ionic liquids, the described ionic liquids provide robust fluorescence properties and remarkably increased UV–Vis absorption. This research may enrich the field of functionalized ionic liquids and provide a platform for extension of ionic liquid applications.     

D,L‐α‐Tocopherol Synthesis Catalyzed by the Brønsted Acidic Ionic Liquids

Abstract

The synthesis of D,L‐α‐tocopherol from trimethylhydroquinone and isophytol using the Brønsted acidic SO₃H‐functionalized ionic liquids as catalysts was explored. The catalytic activities of the SO₃H‐functionalized ionic liquids were dependent on their anions. The yield of D,L‐α‐tocopherol also depended on the solvent, which was the reaction medium. A yield of 94.3% was obtained using the SO₃H‐functionalized ionic liquid with [BF₄ ^?] anion as catalyst in propylene carbonate/heptane. The reaction mixture exhibited good biphasic behaviors, so that the produced D,L‐α‐tocopherol could be separated by decantation. The SO₃H‐functionalized ionic liquids could be reused after the removal of water.     

含氰基基团的以C为中心的不对称阴离子离子液体的合成、表征及应用

首次通过不对称阴离子的钠盐/钾盐和不同的季胺化的咪唑,吡咯溴盐/氯盐进行离子交换,合成了一系列含氰基官能团的不对称阴离子功能化离子液体。通过红外、核磁共振、质谱和元素分析对离子液体的结构进行表征;通过TGA对离子液体的热稳定性进行测定,结果发现不对称功能化离子液体具有良好的热稳定性,其分解温度在219-319℃范围内。将功能化离子液体[Bmim][C(CN)2COCH3]作为弱配体应用于模型的Suzuki偶联反应,发现在反应中加入功能化离子液体[Bmim][C(CN)2COCH3]可以使反应收率提高10-15%。     

Greener synthesis of new ammonium ionic liquids and their potential as extracting agents

New hydrophobic ionic liquids were synthesized from tricaprylmethylammonium chloride (Aliquat 336^©) and selected Bronsted acids by a sustainable, simple and cost-saving deprotonation-metathesis route. Prepared ionic liquids were evaluated as potential extracting agents for cadmium from different aqueous solutions. High efficiency and selectivity were reached for the extraction of cadmium from a natural river matrix with tricaprylmethylammonium thiosalicylate, [A336][TS], a thiol-containing task specific ionic liquid.     

Improvement of the chromatographic separation performance of an imidazolium ionic liquid functionalized silica column by in situ anion‐exchange with dodecyl sulfonate and dodecylbenzene sulfonate anions

The anionic part of ionic liquids can provide additional interactions during chromatographic separations. In this work, the chromatographic separation performance of a silica column functionalized with 1‐propyl‐3‐methylimidazolium chloride ionic liquid was improved by in situ anion‐exchange from chloride anions to dodecyl sulfonate anions and dodecylbenzene sulfonate anions. The separation performances of these ionic liquid functionalized phases were investigated and compared with each other using polycyclic aromatic hydrocarbons, phthalates, parabens, and phenols as model compounds. Results indicated that the new columns presented a better chromatographic separation than the original one. This was ascribed retention mechanism from organic anions. The introduction of dodecyl sulfonate anions increased the hydrophobicity of stationary phase. Furthermore, the phenyl groups of dodecylbenzene sulfonate anions could provide an enhanced selectivity to aromatic compounds such as polycyclic aromatic hydrocarbons by π–π interactions. Analysis repeatability of the new columns was satisfactory (RSD of retention time, 0.10–0.40%; RSD of peak area, 0.66–0.84%).     

果糖在酸性离子液体中脱水制备5-羟甲基糠醛

制备了多种离子液体,并将其作为催化剂和溶剂催化果糖脱水制备5-羟甲基糠醛（HMF）。 制备的酸性离子液体包括磺酸基功能化酸性离子液体、咪唑类酸性离子液体和吡啶类酸性离子液体。 利用核磁共振仪和红外光谱仪对离子液体的结构进行表征。 利用紫外可见光分光光度计结合Hammett指示剂计算Hammett酸度函数,比较了酸强度的大小对反应的影响。 结果表明,离子液体的酸强度对反应有较大影响,在无其它催化剂和溶剂的情况下,离子液体具有较高的催化活性,通过使用1-丁基-3-甲基咪唑氯盐(BmimCl)作为催化剂,当反应温度为120 ℃,反应进行到4 h时,HMF收率可以达到74.97%。     

Synthesis of Novel Greener Functionalized Ionic Liquids Containing Appended Hydroxyl

Novel “greener” functionalized ionic liquids have been prepared by the reaction of 1,2‐epoxy propane and dilute sulfuric acid with [EMIm]Br or [BMIm]Br formed by alkyl bromide (RBr) and 1‐methylimidazole. This kind of ionic liquid could be possibly used as green solvent and catalyst, especially as phase‐transfer catalyst in organic chemistry (e.g., the synthesis of ethoxybenzene). Their chemical structures were characterized by ¹H NMR, ¹³C NMR, and IR.     

A group contribution method to estimate the densities of ionic liquids

Densities of ionic liquids at different temperature and pressure were collected from 84 references. The collection contains 7381 data points derived from 123 pure ionic liquids and 13 kinds of binary ionic liquids mixtures. In terms of the collected database, a group contribution method based on 51 groups was used to predict the densities of ionic liquids. In group partition, the effect of interaction among several substitutes on the same center was considered. The same structure in different substitutes may have different group values. According to the estimation of pure ionic liquids’ densities, the results show that the average relative error is 0.88% and the standard deviation (S) is 0.0181. Using the set of group values three pure ionic liquids densities were predicted, the average relative error is 0.27% and the S is 0.0048. For ionic liquid mixtures, they are thought considered as idea mixtures, so the group contribution method was used to estimate their densities and the average relative error is 1.22% with S is 0.0607. And the method can also be used to estimate the densities of MCl_x type ionic liquids which are produced by mixing an ionic liquid with a Cl^? anion and a kind of metal chloride.     

Molecularly imprinted SPE coupled with HPLC for the selective separation and enrichment of alkyl imidazolium ionic liquids in environmental water samples

A novel 1‐butyl‐3‐methylimidazolium chloride ionic liquid surface imprinted solid‐phase sorbent was synthesized. The as‐prepared material was characterized by SEM, Brunauer–Emmett–Teller surface area analysis and Fourier Transform IR measurements. Then its adsorption properties for alkyl imidazolium ionic liquids, including adsorption capacities, adsorption kinetics, and properties of selective separation and enrichment were studied in detail. It was shown that the ionic liquid surface imprinted polymer exhibited high selective recognition characteristics for the imidazolium chloride ionic liquids with short alkyl chains (C_nmimCl, n = 2, 4, 6, 8) and the adsorption equilibrium was achieved within 25 min. Various parameters were optimized for the 1‐butyl‐3‐methylimidazolium chloride ionic liquid surface imprinted polymer SPE column, such as flow rate, eluent solvent, selectivity, and reusability of the column. Then, the SPE column coupled with HPLC was used for the determination of alkyl imidazolium ionic liquids. Experimental results showed that the existence of their structural analogs and common concomitants in environmental matrices did not affect the enrichment of 1‐butyl‐3‐methyl imidazolium chloride ionic liquid. The average recoveries of 1‐butyl‐3‐methylimidazolium chloride ionic liquid in spiked water samples were in the range of 92.0–102.0% with the RSD lower than 5.8%.     

Room-Temperature Synthesis of the Bi5[GaCl4]3 Salt From Three Different Classes of Ionic Liquids

Following the development in the synthesis of subvalent cluster compounds, we report on the use of three different classes of room-temperature ionic liquids for the synthesis of the pentabismuth-tris(tetragallate) salt, Bi₅[GaCl₄]₃, characterized by X-ray diffraction. The Bi₅[GaCl₄]₃ salt was prepared by reduction of BiCl₃ using gallium metal in ionic liquid reaction media containing a strong Lewis acid, GaCl₃. The ionic liquids; trihexyltetradecyl phosphonium chloride [Th-Td-P⁺]Cl^?, 1-dodecyl-3-methylimidazolium chloride [Dod-Me-Im⁺]Cl^? and N-butyl-N-methylpyrrolidinium chloride [Bu-Me-Pyrr⁺]Cl^? from three of the main classes of ionic liquids were used in synthesis. Reactions using ionic liquids composed of the trihexyltetradecyl phosphonium cation [Th-Td-P⁺] and the anions; tetrafluoroborate [BF₄ ^?], bis(trifluoro-methyl sulfonyl) imide [(Tf)₂N^?] and hexafluorophosphate [PF₆ ^?] were also investigated.     

Sensitive Amperometric Determination of Thiocyanates at Ionic Liquid Nanohybrid Kaolinite Modified Glassy Carbon Electrode

Electrochemical sensors have been developed by modifying a glassy carbon electrode with organo‐kaolinite hybrid materials. These materials were obtained by the grafting of four ionic liquids (1‐(2‐hydroxyethyl)‐4‐benzylpyridinium chloride, 1‐(2‐hydroxyethyl)‐4‐(tert‐butyl)pyridinium chloride, 1‐(2‐hydroxyethyl)‐4‐ethylpyridinium chloride and 1‐(2‐hydroxyethyl)‐4‐methylpyridinium chloride) on the interlayer aluminol surfaces of kaolinite. With the presence of ionic liquids in the interlayer space of kaolinite, the hybrid materials acquired anion exchange properties and were successfully applied as electrode modifier for the electroanalysis of thiocyanate (SCN⁻), an anion of medical and environmental concern. A pre‐concentration/detection strategy was used to overcome the interfering effect of the electrolytic solution. After the optimisation of some key experimental parameters (sodium nitrate as electrolyte, 5 min of accumulation time) calibration curves were plotted. Excellent linearity was obtained in the low concentration region (1×10⁻⁶ M to 4×10⁻⁵ M). The lowest detection limit (15 nM) was obtained with the benzylpyridinium functionalized kaolinite and the highest (60 nM) with the methylpyridinium functionalized kaolinite. Interfering anions (NO₃⁻, Cl⁻, SO₄²⁻ and CH₃COO⁻) present in the pre‐concentration solution were found to interfere with SCN⁻ but the sensors remained stable and produced reproducible signals. The most sensitive sensor was successfully applied for the amperometric determination of SCN⁻ in human saliva samples.     

An efficient and green sonochemical synthesis of some new eco-friendly functionalized ionic liquids

Considerable stress to replace a lot of volatile organic compounds which were used as solvents in synthetic organic chemistry has been done for many chemical industries. A suitable solution for these problems is found by using the ionic liquids as a clean medium of working and avoiding the solvent effect. The present work describes a facile and green ultrasound-assisted procedure as an environmentally friendly alternative to traditional methods for the preparation of a series of 26 new functionalized imidazolium-based ionic liquids. Their structures were characterized by FT-IR, ¹H, ¹³C, ¹¹B, ¹⁹F, ³¹P NMR and mass spectra.     

手性胍盐离子液体的合成

以1,3-二甲基-2-咪唑啉酮, α-甲基苄胺为原料, 三步合成了手性胍的氯盐, 再经复分解反应, 共合成了14种手性胍离子液体并对其结构性质进行了表征. 该类离子液体有望用于催化不对称Henry 反应、Michael加成反应等.     

Synthesis and Thermophysical Properties of Ether‐Functionalized Sulfonium Ionic Liquids as Potential Electrolytes for Electrochemical Applications

During this work, a novel series of hydrophobic room temperature ionic liquids (ILs) based on five ether functionalized sulfonium cations bearing the bis{(trifluoromethyl)sulfonyl}imide, [NTf₂]^? anion were synthesized and characterized. Their physicochemical properties, such as density, viscosity and ionic conductivity, electrochemical window, along with thermal properties including phase transition behavior and decomposition temperature, have been measured. All of these ILs showed large liquid range temperature, low viscosity, and good conductivity. Additionally, by combining DFT calculations along with electrochemical characterization it appears that these novel ILs show good electrochemical stability windows, suitable for the potential application as electrolyte materials in electrochemical energy storage devices.     

Preparation and characterization of functionalized precipitated silica SYLOID® 244 using ionic liquids as modifiers

Studies were performed on the chemical modification of SYLOID^® 244 (Grace) precipitated silica using ionic liquids. The unmodified and ionic‐liquid‐functionalized silica were subjected to a comprehensive physicochemical and dispersive evaluation. Particle size, polydispersity and specific surface area (BET) and porous structure were examined. Moreover, stability of the colloids obtained was evaluated by estimation of isoelectric points. The extent of modification and its type were defined using fourier transform infrared spectroscopy and ²⁹Si‐cross‐polarization/magic angle spinning/nuclear magnetic resonance techniques. The modification was not observed to deteriorate the dispersive properties of the silica. The silicas obtained exhibited a restricted tendency to form larger accumulations of particles, i.e. aggregates and agglomerates. Moreover, application of ionic liquids with a heptyloxymethyl or octyloxymethyl substituent resulted in complete hydrophobization of the silica surface. Tested powders manifested the highest stability within a pH range of 10–12. Copyright © 2004 John Wiley & Sons, Ltd.     

以N为中心的阴离子离子液体的合成、表征及应用

首次通过不同阴离子的钾盐和不同的季铵化的咪唑,吡咯溴盐/氯盐进行离子交换,合成了一系列含氰基官能团的阴离子功能化离子液体。通过红外、核磁共振、质谱对离子液体的结构进行表征;通过TGA对离子液体的热稳定性进行测定,结果发现功能化离子液体具有良好的热稳定性,其分解温度在224-289℃范围内。将功能化离子液体[EMIm][N(CN)COC2H5]作为配体应用于无膦配体的Suzuki偶联反应,发现在反应中加入功能化离子液体[EMIm][N(CN)COC2H5]可以使反应收率提高10-20%。     

Separation and indirect ultraviolet detection of ferrous and trivalent iron ions by using ionic liquids in ion chromatography

A method of simultaneous separation and indirect ultraviolet detection of different valence iron ions Fe²⁺ and Fe³⁺ by using ionic liquids as mobile phase additives and ultraviolet absorption reagents on a cation exchange column functionalized with carboxylic acid group was developed. The effects of ionic liquids, organic acids, detection wavelength, etc. on separation and detection of Fe²⁺ and Fe³⁺ were investigated and the mechanism was discussed. The pyridinium and imidazolium ionic liquids were not only ultraviolet absorption reagents of indirect ultraviolet detection but also effective components for separating Fe²⁺ and Fe³⁺. The separation and detection of Fe²⁺ and Fe³⁺ can be achieved using 0.5 mmol/L pyridinium ionic liquid?1.2 mmol/L methanesulfonic acid as the mobile phase. The determination of Fe²⁺ and Fe³⁺ had a good linear relationship in the concentration range of 1?100 mg/L. The limits of detection of Fe²⁺ and Fe³⁺ were 0.12 and 0.09 mg/L, respectively. This method was applied to the actual sample detection in the field of medical analysis. The spiked recoveries were between 97.3 and 99.5%, and the relative standard deviations were less than 0.6%. The method is simple, accurate, and reliable, and is an analytical method with universal and practical value.     

Preparation of 3,6-dibenzoylacenapthene in the presence of Lewis acidic ionic liquids

The reactivity of Lewis acidic ionic liquids for the acylation of acenaphthene to 3,6-dibenzoylacenaphthene was investigated. Ionic liquids of different alkyl chain length and metal chloride were synthesized and tested for the reaction to discuss the effects of Lewis acidity of the ionic liquid on the alkylation. Pure 3,6-dibenzoylacenaphthene was obtained and the structure of 3,6-dibenzoylacenaphthene was identified by GC/MS, FT-IR and ¹H NMR spectra. [Emim]C1/A1C1₃ ionic liquid was found to be the most active catalyst in the acylation. The yield of 3,6-dibenzoylacenaphthene was up to 89.6% and the selectivity towards 3,6-dibenzoylacenaphthene was up to 92.2%. The experiment shows that [Emim]Cl/AlCl₃ can be used as both catalyst and solvent, it is reusable and environmentally friendly for the preparation of 3,6-dibenzoylacenaphthene.     

Ionic Liquid‐Based Routes to Conversion or Reuse of Recycled Ammonium Perchlorate

New, potentially green, and efficient synthetic routes for the remediation and/or re‐use of perchlorate‐based energetic materials have been developed. Four simple organic imidazolium‐ and phosphonium‐based perchlorate salts/ionic liquids have been synthesized by simple, inexpensive, and nonhazardous methods, using ammonium perchlorate as the perchlorate source. By appropriate choice of the cation, perchlorate can be incorporated into an ionic liquid which serves as its own electrolyte for the electrochemical reduction of the perchlorate anion, allowing for the regeneration of the chloride‐based parent ionic liquid. The electrochemical degradation of the hazardous perchlorate ion and its conversion to harmless chloride during electrolysis was studied using IR and ³⁵Cl NMR spectroscopies.     

含氰基离子液体的合成、表征及流变性质研究

摘要合成、 表征了一系列新的含氰基咪唑类离子液体. 测定了该离子液体的密度、 熔点及溶解性等物理性质, 研究了其在稳态、 瞬态和动态条件下的流变行为. 结果表明, 当剪切速率在0.1～50 s^-1范围内时, 其粘度不随剪切速率的变化而变化, 但随温度升高而降低, 粘流活化能随取代基长度变化呈现规律性变化. 对于1-丁基-3-氰乙基咪唑六氟磷酸盐离子液体, 维持剪切速率不变时, 其剪切应力和粘度均不随时间变化, 且随着温度的升高而降低; 在动态条件下, 在线性粘弹区, 复合粘度和损耗模量G″ 随温度升高而降低. 关键词