Synthesis and Aggregation Behavior of Trisiloxane Ionic Liquids in Aqueous Solution

Trisiloxane ionic liquids with polyether groups (Si₃pyCl-EO₃) were synthesized via thiol-ene reaction between 1-methyl-1-[bis(vinyldimethylsiloxy)methyl]silylpropylpyrrolidinium chloride (Vi-Si₃pyCl) and tri(ethylene glycol) methyl ether thiol. The aggregation behavior of the trisiloxane ionic liquids, Si₃pyCl-EO₃ and Vi-Si₃pyCl, in aqueous solution was investigated using surface tension, electrical conductivity, dynamic light scattering, and transmission electron microscopy. The structures of trisiloxane ionic liquids can obviously influence their aggregation behavior. Vi-Si₃pyCl has excellent surface activity (22.3 mN m⁻¹). However, Si₃pyCl-EO₃ can only reduce the surface tension of water to 33.5 mN m⁻¹. In comparison with Vi-Si₃PyCl, Si₃PyCl-EO₃ has a bulkier hydrophobic group and a higher Α_min value (127.8 Ų) caused by the introduction of the tri(ethylene glycol) methyl ether groups by thiol-ene reaction. The micellization of Vi-Si₃PyCl is entropy driven, while the aggregation process of Si₃PyCl-EO₃ in aqueous solution is enthalpy driven.     

Extraction of Azo Dyes from Aqueous Solutions with Room Temperature Ionic Liquids

In this work, ionic liquids/water distribution ratios (D) of azo dyes, including 1-(phenylazo)-2-naphthol, 1-(2-pyridylazo)-2-naphthol, 4-(nitrophenylazo)resorcinol, 4-(2-pyridylazo) resorcinol, and 2-(4-dimethylaminophenylazo) benzoic acid, have been determined experimentally. It was found that the D values are highly influenced by the pH of the water phase and the type of salts added. They increase with increasing alkyl chain length on the cations of the ionic liquids, and the anionic effect follows the order [BF₄]^? > [PF₆]^?. Possible extraction mechanism and selective separation of some azo dyes are also investigated. The results suggest that ionic liquids have potential applications in the removal and selective separation of azo dyes from water.     

普通离子液体和功能化离子液体的合成研究进展

离子液体是在室温下为液体、具有离子特性的新型绿色溶剂,作为一类环境友好型的反应介质,在诸多领域有其独特的性质.综述了普通离子液体和功能化离子液体的合成研究进展,并对其前景进行了展望.     

纤维素在离子液体水溶液中的溶胀与溶解行为的研究

以含水的离子液体1-丁基-3-甲基咪唑氯盐([BMIM]C)l为溶剂,研究了纤维素在其中的溶胀和溶解行为。通过偏光显微镜观察发现,[BMIM]Cl水溶液中的含水率对纤维素浆粕的溶胀与溶解行为有着重要的影响,主要表现为三种状态:当[BMIM]Cl中含水率小于1%时,浆粕纤维横向被迅速切断并快速溶解,没有发现明显的溶胀现象;当[BMIM]Cl中含水率在2%～5%时,浆粕纤维发生了非常明显的非均相溶胀,但并不溶解;而当[BMIM]Cl中含水率进一步增大到6%～20%时,浆粕纤维不再发生明显的溶胀现象。此外,研究结果还表明,当[BMIM]Cl中含水率在2%～5%时,溶胀温度和[BMIM]Cl中的含水率对于纤维素的溶胀有很大影响,随着温度升高,浆粕纤维的溶胀速度增大,达到最大溶胀比所需要的时间缩短;而随着[BMIM]Cl中含水率的提高,浆粕纤维在[BMIM]Cl水溶液中达到的最大溶胀比减小。     

Salting-out in Aqueous Solutions of Ionic Liquids and K3PO4: Aqueous Biphasic Systems and Salt Precipitation

The salting-out effect produced by the addition of potassium phosphate, K₃PO₄ to aqueous solutions of water-miscible ionic liquids, viz. 1-ethyl-3-methylimidazolium ethyl sulfate, 1-butyl-3-methylimidazolium methyl sulfate, or 1-alkyl-3-methylimidazolium chloride (alkyl = butyl, octyl or decyl) is investigated. The effects are analyzed using both the corresponding temperature–composition pseudo-binary and composition ternary phase diagrams. Different regions of liquid-liquid and solid-liquid phase demixing are mapped. The phase behavior is interpreted taking into account the complex and competing nature of the interactions between the ionic liquid, the inorganic salt and water. In the case of solutions containing 1-octyl- or 1-decyl-3-methylimidazolium chloride, the smaller magnitude of the salting-out effects is explained in terms of the possibility of self-aggregation of the ionic liquid.     

Prediction of Selective Extraction of Cresols from Aqueous Solutions by Ionic Liquids Using Theoretical Approach

This work reports the prediction of selective extraction of cresol from aqueous solutions using ionic liquids (ILs) as the solvent. Judicious screening of various ILs was carried out for all the three forms of cresol (i.e., o-cresol, m-cresol, and p-cresol). A quantum chemical based theoretical model “conductor-like screening model for real solvents” (COSMO-RS) was used to predict the selectivity of cresol in aqueous medium at infinite dilution. A screening of 360 possible ILs from 15 cations and 24 anions was carried out to determine the best IL for the removal of cresol from water. Amongst the phosphonium and imidazolium based cations, trihexyl tetradecylphosphonium [THTDP] and 1-octyl-3-methylimidazolium [OMIM] gave the highest selectivity other than the anions bromide and chloride. The selectivities for different cresols followed the pattern: m-cresol > p-cresol > o-cresol. Similarly for pyridinium and quinolium based cations, 1-ethylpyridinium [EPY] and 1-octylquinolium [OQU] gave the highest selectivity. Amongst the two cations studied for pyrrolidinium based cations, 1-hexyl-1-methylpyrrolidinium [HMPL] was the best. Trihexyl tetradecylphosphonium salicyclate [THTDP][SAL] gave the highest selectivity of 662 amongst all the ILs screened.     

Kinetic Model of Two‐Phase Epoxidation with Ionic Liquids as Micellar Catalysts

The biphasic catalytic epoxidation of cyclooctene using the ionic liquid (IL) 1,2‐dimethyl‐3‐octyl‐imidazolium perrhenate ([OMMIM]ReO₄) as micellar catalyst and H₂O₂ as oxidant was investigated. Kinetic experiments were carried out in the intrinsic kinetic regime as proved by variation of stirring rate and temperature. Variation of catalyst concentration allowed for determination of the critical micellar concentration (CMC) of the catalytic IL. The effect of substrate concentrations on the reaction rate was also assessed. Based on the experiments, a kinetic model adapted from enzyme catalysis was proposed to account for the micellar reaction environment. The model takes into account the onset of micelle formation at the CMC. The application of the kinetic model illustrated the good agreement with the experimental data. The model will be applied to other micellar epoxidation reactions and for the design of an appropriate reaction setup in the future.     

Thermo‐Rheology of a Proline‐Based Surface‐Active Ionic Liquid: Mixtures with Water and n‐Octane

Surfactant flooding is one of the most promising techniques to recover oil from unprofitable reservoirs. Surface‐active ionic liquids can overcome the limitations of the current surfactants. The rheology of the injecting solutions and the formed slugs is critical in the evaluation of an enhanced oil recovery process. The thermo‐rheological behavior of a biodegradable surface‐active ionic liquid, [ProC₄]DS, and the corresponding binary and ternary mixtures with water and n‐octane was studied. All flow curves exhibited shear‐thinning and thixotropic behavior. The viscoelastic behavior of the ternary samples depended strongly on the [ProC₄]DS content. Three different regions were identified: typical liquid‐like behavior, weak gel, and true gel. The thermal profiles indicated that the tested systems were fully thermoreversible.     

聚合离子液体研究进展

综述了近年来有关聚合离子液体的合成、性质和应用研究进展,重点介绍了聚合离子液体结构与性能的关系。通过离子液体单体的可控聚合或对聚合物前体进行修饰等方法,能够获得具有特定结构的功能性聚合离子液体。聚合离子液体具有优良的离子导电性和良好的力学性能及加工性能,在电池材料、吸附分离、生物和催化等诸多领域具有广阔的应用前景。     

离子液体中的电化学有机合成

综述了离子液体在电化学有机合成中的应用,包括苯胺的聚合反应、吡咯的聚合反应、噻吩的聚合反应、环合反应、氧化还原反应、硅氧烷的制备反应以及氟化脱硫反应等。这些反应具有工艺清洁,条件温和,收率高,产物分离容易等优点,非常适合于精细化学品的工业化生产。离子液体掺杂的聚合物材料由于具有更为优越的性能,尤其引起了广泛关注。     

Theoretical Aspects of Ionic Liquids for Soft‐Matter Sciences

The thermodynamic and electrochemical properties of ionic liquids produce a broad spectrum of unconventional phenomena both microscopically and macroscopically. However, despite numerous theoretical and experimental studies, the fundamental roles of the relevant interactions such as electrostatic interactions and hydrogen bonding often remain unclear at the molecular level. The complexity of the molecular interactions typically increases when ionic liquids dissolve polymers or polar substances such as water. Accordingly, recent studies have revealed new features of ionic liquids. Further insights into the role of the molecular polarity of ionic liquids are required. This article presents an overview of the important phenomena of ionic liquids concerning soft‐matter sciences based on selected experimental and theoretical studies. We focus on the effect of the dielectric response of ionic liquids to distinguish ionic liquids from common inorganic salts, such as alkali metal halides.     

离子液体在气体吸附中的研究进展

综述了气体在离子液体中的溶解性能、影响因素及其传质机理;介绍了CO2、SO2等气体在离子液体中的吸附研究进展;总结了离子液体中气体分离、分析及有气体参与的化学反应等领域的研究现状,并展望了离子液体在气体吸附方面的应用前景。     

离子液体在烷基化反应中的应用

离子液体作为一种环境友好的催化剂和溶剂,受到了人们日益的关注。本文介绍了离子液体独特的性质,重点对离子液体在催化烯烃烷基化制高辛烷值烷基化汽油、苯与烯烃的烷基化制烷基苯,苯与卤代烷烃的烷基化以及萘、酚的烷基化反应中的应用进行综述。在这些反应中,离子液体不仅表现出良好的催化活性和选择性,同时具有产品易分离,催化剂可以循环使用,环境污染小和设备腐蚀不严重等优点。     

离子液体在精细化学品合成中的应用

概述了近几年离子液体在医药、食品添加剂、农药等精细化学品合成中的应用。离子液体表现出的主要优势在于:它无毒无害,对环境友好,可以替代有毒、腐蚀性的溶剂或催化剂;反应速度快,条件温和,收率高,选择性好,特别适合高纯产物的合成;中间体无需分离,多步合成操作过程可以连续进行,简化了合成工艺;产物易分离,离子液体/催化剂可循环使用;离子液相有机合成具有比固相合成担载量高的优势,适用于药物的组合化学合成中。设计合成高效、多功能、价廉、易降解的离子液体,将加速离子液体由基础研究到中试研究和工业应用的步伐,使之在精细化学品合成中带来更大的经济、环境效益。引文36篇。     

离子液体中酶催化反应的研究进展

讨论了近年来离子液体作为酶催化反应介质的应用发展。说明了不同类别的酶在离子液体或水合离子液体两相体系中具有催化活性，尤其是脂肪酶，在无水的离子液体介质反应体系中不仅能保持很好的活性，其手性选择性和操作稳定性往往优于传统介质中的表现。指出了离子液体的环境相容性使其成为绿色生物反应工程新的应用溶剂。对不适于在传统溶剂体系中进行的生物催化再生和产物回收研究，离子液体溶剂已经逐渐表现出其优势。     

离子液体用于汽油脱硫的研究进展

离子液体可通过萃取分离、催化作用和电化学聚合等方法降低汽油中的硫含量。对离子液体用于汽油脱硫的研究进展及离子液体脱硫产业化应用存在的问题进行了综述,并对未来的研究方向提出了建议。     

室温离子液体的应用

介绍了室温离子液体作为一类绿色溶剂和催化剂体系在分离过程、化学反应、电化学等领域的应用情况;同时离子液体还可以作为润滑材料、敏感材料、储能材料和光学材料.分析了在离子液体研究过程中存在的问题,展望了离子液体的应用前景.     

离子液体在萃取有机物方面的应用

近些年来,世界各国学者对离子液体的研究越来越多,随着对离子液体研究的深入,离子液体的应用逐渐渗透到各个领域中。主要介绍近年来离子液体在萃取有机物方面的应用进展。     

添加剂对氯铝酸离子液体催化异丁烯齐聚反应的影响

含有AlCl4-和/或Al2Cl7-阴离子的氯铝酸离子液体对异丁烯齐聚反应有很强的催化活性,但反应的选择性较差。改变离子液体本身的阴、阳离子种类不能提高反应的选择性。在氯铝酸离子液体中引入Cu+进行改性,改性后离子液体的阴离子具有双金属的配位中心,能够有效抑制齐聚过程中裂化等副反应的发生,改善目标产物的选择性。当氯化亚铜与氯铝酸离子液体的物质的量比为0.1时,液相产物中二聚物和三聚物的含量达到60%以上。     

Application of Ionic Liquids in Hydrometallurgy

Ionic liquids, low temperature molten salts, have various advantages manifesting themselves as durable and environmentally friendly solvents. Their application is expanding into various fields including hydrometallurgy due to their unique properties such as non-volatility, inflammability, low toxicity, good ionic conductivity, and wide electrochemical potential window. This paper reviews previous literatures and our recent results adopting ionic liquids in extraction, synthesis and processing of metals with an emphasis on the electrolysis of active/light, rare earth, and platinum group metals. Because the research and development of ionic liquids in this area are still emerging, various, more fundamental approaches are expected to popularize ionic liquids in the metal manufacturing industry.