Cationic polymerization of vinyl ethers with alkyl or ionic side groups in ionic liquids

Controlled cationic polymerization of isobutyl vinyl ether was demonstrated to proceed in an ionic liquid (IL), 1‐butyl‐3‐octylimidazolium bis(trifluoromethanesulfonyl)imide, using a 1‐(isobutoxy)ethyl acetate/TiCl₄ initiating system, ethyl acetate as an added base, and 2,6‐di‐tert‐butylpyridine as a proton trap reagent. Judicious choices of metal halide catalysts, counteranions of ILs, and additives were essential for controlling the polymerization. The polymerization proceeded much faster in the IL than in CH₂Cl₂, indicating an increased population of ionic active species in the IL due to the high polarity. Polymers with a relatively narrow molecular weight distribution were obtained in the IL with a bis(trifluoromethanesulfonyl)imide ( ) anion even in the absence of an added base, which suggested possible interactions of the counteranion of the IL with the growing carbocations. Moreover, the direct cationic polymerization of a vinyl ether with pendant imidazolium salts, 1‐(2‐vinyloxyethyl)‐3‐methylimidazolium bis(trifluoromethanesulfonyl)imide, proceeded in a homogeneous state in 1‐methyl‐3‐octylimidazolium bis(trifluoromethanesulfonyl)imide. The solubilities of the obtained polymers were readily tuned by counteranion exchange. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1774–1784     

From crown ethers to zeolites: Reaction of EtAlCl2 with crown ethers

In contrast to aluminum alkyls, alkyl aluminum halides such as EtAlCl₂ react with crown ethers to form cation-anion pairs which exhibit the liquid clathrate effect. Specifically, [12-C-4·AlCl₂][AlCl₃Et] and [18-C-6·AlCl₂][AlCl₃Et] have been isolated and characterized by X-ray diffraction techniques. The cations show aluminum in an octahedral environment made up of four of the oxygen atoms from the crown and two chlorine atoms. The 12-C-4 derivative crystallizes in the monoclinic space group P2₁/c with cell constants of a=7.497(4), b=22.121(8), c=12.339(5) Å, =94.99(3)^o, and Z=4 for =1.43 g cm^–3. Least-squares refinement based on 1413 observed reflections led to a final conventional R value of 0.093. The 18-C-6 complex belongs to the triclinic space group P1 with a=8.414(4), b=12.193(6), c=12.394(6) Å, =73.14(4), =86.07(4), =81.52(4)^o, and Z=2 for =1.45 g cm^–3. Refinement based on 2605 observed reflections led to R=0.063. The complex aluminum-containing species are related to a class of compounds called aluminoxanes.     

冠醚-离子液体体系对水相中锶离子的萃取研究

本文研究了以一系列离子液体作为介质时,萃取剂二环己基18冠6（DCH18C6）对水相中Sr^2＋的萃取行为．研究结果表明,DCH18C6／离子液体体系对Sr^2＋的萃取性能优于相应的DCH18C6／JE辛醇萃取体系,一定条件下其萃取Sr^2＋的分配比可达10^3量级．同时,体系对Sr^2＋的萃取性能随着离子液体的结构不同而有所差别．在离子液体萃取体系中,随着水相初始硝酸浓度的增加,对Sr^2＋的萃取性能下降．水相中Na^＋、K^＋等离子的存在也会对体系萃取Sr^2＋产生直接影响．本文还验证了离子液体体系萃取Sr^2＋的机理,即以阳离子交换机理为主实现对Sr^2＋的萃取．     

室温离子液体催化正己烷异构化反应的研究

由无水三氯化铝与盐酸三乙胺按照不同摩尔比合成了具有不同酸度的室温离子液体,并考察了其酸性以及对正己烷异构化反应的催化性能。结果发现,随着离子液体合成时AlCl3比例的增大,离子液体的酸性增强,且离子液体2AlCl3/Et3NHCl对正己烷异构化显示出优良的催化性能。针对离子液体2AlCl3/Et3NHCl,考察了反应时间、反应温度和催化剂用量（剂油体积比）对正己烷异构化反应的影响。结果表明,反应条件对异构烷烃选择性的影响不大,但是对原料转化率、异构烷烃产率和液体收率有较大的影响。离子液体催化正己烷异构化的最佳反应条件,反应温度为50℃,反应时间为45min,剂油体积比为1∶1。     

Extraction of organic compounds with room temperature ionic liquids

Room temperature ionic liquids are novel solvents with a rather specific blend of physical and solution properties that makes them of interest for applications in separation science. They are good solvents for a wide range of compounds in which they behave as polar solvents. Their physical properties of note that distinguish them from conventional organic solvents are a negligible vapor pressure, high thermal stability, and relatively high viscosity. They can form biphasic systems with water or low polarity organic solvents and gases suitable for use in liquid–liquid and gas–liquid partition systems. An analysis of partition coefficients for varied compounds in these systems allows characterization of solvent selectivity using the solvation parameter model, which together with spectroscopic studies of solvent effects on probe substances, results in a detailed picture of solvent behavior. These studies indicate that the solution properties of ionic liquids are similar to those of polar organic solvents. Practical applications of ionic liquids in sample preparation include extractive distillation, aqueous biphasic systems, liquid–liquid extraction, liquid-phase microextraction, supported liquid membrane extraction, matrix solvents for headspace analysis, and micellar extraction. The specific advantages and limitations of ionic liquids in these studies is discussed with a view to defining future uses and the need not to neglect the identification of new room temperature ionic liquids with physical and solution properties tailored to the needs of specific sample preparation techniques. The defining feature of the special nature of ionic liquids is not their solution or physical properties viewed separately but their unique combinations when taken together compared with traditional organic solvents.     

Olefin metathesis in room temperature ionic liquids using imidazolium-tagged ruthenium complexes

New recyclable imidazolium-tagged ruthenium catalysts have been developed to perform olefin metathesis in room temperature ionic liquids (RTILs). High level of recyclability combined with a high reactivity were obtained in the ring-closing metathesis (RCM) of a variety of di- or tri-substituted and/or oxygen-containing dienes. Extremely low residual ruthenium levels were detected in the RCM products (average of 7.3 ppm per run). Several examples of olefin cross-metathesis (CM) have been also studied.     

Application of novel room temperature ionic liquids in flexible supercapacitors

This paper studied application of different types of room temperature ionic liquids (RTILs) into flexible supercapacitors. Typical RTILs including 1-buthyl-3-methyl-imidazolium [BMIM][Cl], trioctylmethylammonium bis(trifluoromethylsulfonyl)imide [OMA][TFSI] and triethylsulfonium bis(trifluoromethylsulfonyl)imide ([SET₃][TFSI]) were studied. [SET₃][TFSI] shows the best result as electrolyte in electrochemical double-layer (EDLC) supercapacitors with very high specific capacitance of 244 F/g at room temperature, overceiling the performance of conventional carbonate electrolyte such as dimethyl carbonate (DMC) with more stable performance and much larger electrochemical window.     

室温离子液体催化巯基乙酸异辛酯的合成

巯基乙酸异辛酯是一种广泛应用于精细化工、树脂和塑料制造的中间体,尤其在聚氯乙烯无毒制品中有着重要用途[1],其合成方法的改进也成为研究的主要课题之一。巯基乙酸异辛酯的合成通常采用硫酸催化法[2],由于浓硫酸污染环境、腐蚀设备,特别是近年来环保法规对环境和安全性不断提高的要求,用固体酸(分子筛、离子交换树脂、固体超强酸)等取代H2SO4、HF、A lC l3等强腐蚀性酸作为催化剂的催化工艺获得明显进展[3],但这些催化剂也有自身的缺点[4]。室温离子液体是近年来受到极大关注的一类新材料,它为人们探索环境友好的催化体系和溶剂提供了…     

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).     

Mesoscopic structural organization in fluorinated room temperature ionic liquids

The presence of fluorous tails in room-temperature ionic liquids imparts new properties to their already rich spectrum of appealing features. The interest towards this class of compounds that are of ionic nature with melting point less than 25 °C is accordingly growing; in particular, compounds bearing relatively long fluorous tails have begun to be considered. In this invited presentation, we show recent results arising from the systematic study of structural properties of a series of fluorinated room temperature ionic liquids, with growing fluorous chain length. At odd with the current understanding of this class of compounds, we show experimentally that they are characterized by the presence of segregated fluorous domains whose size depends on the fluorous chain length. This experimental finding, based on the synergic use of X-ray and neutron scattering, provides a structural scenario at the mesoscopic spatial scale that is in agreement with the recent state of the art molecular dynamic simulations. We speculate on the potential role of this significant compartmentalization of the bulk liquid phase into different nanoscale domains, as relevant in a series of applications including separation, solubility, catalysis, and so forth.     

单臂冠醚液晶LB膜的相变研究

研究了两种单臂冠醚液晶及配合物(1, 2及1.Eu^3^+)的LB膜的成膜特性,实验发出它们均可在气-液界面形成单分子膜, 但不易转移, 化合物1在压膜过程中出现一维相变。用CPK模型对成膜分子构型和面积进行估算, 其结果与实验相一致, 并讨论了冠醚液晶结构对LB膜相变的影响。     

Direct electrochemistry and electrocatalysis of myoglobin immobilized in hyaluronic acid and room temperature ionic liquids composite film

A novel biocomposite film based on hyaluronic acid (HA) and hydrophilic room temperature ionic liquid 1-ethyl-3-methyl-imidazolium tetrafluoroborate ([EMIM][BF₄]) was explored. Here, HA was used as a binder to form [EMIM][BF₄]-HA composite film and help [EMIM][BF₄] to attaching on glass carbon electrode (GCE) surface, while doping [EMIM][BF₄] in HA can effectively reduce the electron transfer resistance of HA. The composite film can be readily used as an immobilization matrix to entrap myoglobin (Mb). A pair of well-defined and quasi-reversible redox peaks of Mb was obtained at the Mb-[EMIM][BF₄]-HA composite film modified GCE (Mb-[EMIM][BF₄]-HA/GCE) through direct electron transfer between Mb and the underlying electrode. The Mb-[EMIM][BF₄]-HA/GCE showed an excellent electrocatalytic activity toward the reduction of H₂O₂. Based on the [EMIM][BF₄]-HA biocomposite film, a third-generation reagentless biosensor could be constructed for the determination of H₂O₂.     

Catalytic asymmetric hydrogenation of aromatic ketones in room temperature ionic liquids

Polar bisphosphonic acid-derived Ru(BINAP)(DPEN)Cl₂ precatalysts were synthesized and immobilized in room temperature ionic liquids (RTILs) for asymmetric hydrogenation of aromatic ketones with ee values of up to 98.7%. The performance of the Ru catalysts is highly dependent on the nature of imidazolium ILs. For the imidazolium ILs without acidic protons, both ILs and Ru catalysts were recycled by simple extraction and reused. Such a simple immobilization approach also prevented the leaching of Ru (and Ru catalysts) into the chiral secondary alcohol products, and should prove desirable for the production of pharmaceutical intermediates that are free from metal contaminants.     

Green synthesis of three- to five-membered O-heterocycles using ionic liquids

The investigation for replacement of organic solvents in organic synthesis is a growing area of interest due to increasing environmental issues. The use of ionic liquid salts as solvents and catalysts in organic reactions has gained extensive interest. Ionic liquids provided a new environmentally benign and improved alternative to traditional methods in modern synthetic chemistry. The aim of present review is to focus on the applications of ionic liquids for the synthesis of O-heterocycles.     

室温离子液体在分离科学研究中的新进展

室温离子液体作为一种重要的绿色溶剂,由于在金属离子、小分子有机物的萃取分离,气体吸附分离以及作为液相和气相色谱固定相等许多分离过程中体现出高分离效率和高选择性的特点,正在成为分离科学研究的前沿领域.着重总结了从2003—2006年的室温离子液体在分离科学领域中的新进展,并对其应用领域和发展前景做了展望.提出进一步加强离子液体的功能化和固定化技术及其在分离科学中的应用基础研究,探索离子液体有效的回收和再循环利用的新方法,是离子液体今后在分离科学研究中的一系列重要内容.     

Shear-induced lamellar phase of an ionic liquid crystal at room temperature

The phase behaviour of a number of N-alkylimidazolium salts was studied using polarizing optical microscopy, differential scanning calorimetry and X-ray diffraction. Two of these compounds exhibit lamellar mesophases at temperatures above 50°C. In these systems, the liquid crystalline behaviour may be induced at room temperature by shear. Sheared films of these materials, observed between crossed polarisers, have a morphology that is typical of (wet) liquid foams: they partition into dark domains separated by brighter (birefringent) walls, which are approximately arcs of circle and meet at “Plateau borders” with three or more sides. Where walls meet three at a time, they do so at approximately 120° angles. These patterns coarsen with time and both T1 and T2 processes have been observed, as in foams. The time evolution of domains is also consistent with von Neumann's law. We conjecture that the bright walls are regions of high concentration of defects produced by shear, and that the system is dominated by the interfacial tension between these walls and the uniform domains. The control of self-organised monodomains, as observed in these systems, is expected to play an important role in potential applications.     

Synthesis of copolyimides based on room temperature ionic liquid diamines

Block copolyimides based on aromatic dianhydrides and diamines copolymerized with diamino room temperature ionic liquid (RTIL) monomers were synthesized over a range of compositions. Specifically, two diamino RTILs, 1,3‐di(3‐aminopropyl) imidazolium bis[(trifluoromethyl)sulfonyl] imide ([DAPIM] [NTf₂]) and 1,12‐di[3‐(3‐aminopropyl) imidazolium] dodecane bis[(trifluoromethyl) sulfonyl] imide ([C₁₂ (DAPIM)₂] [NTf₂]₂) were synthesized using a Boc protection method. The two RTILs were reacted with 2,2‐bis(3,4‐carboxylphenyl) hexafluoropropane dianhydride (6FDA) to produce 6FDA‐RTILs oligomers that formed the RTIL component for the block copolyimides. The oligomers were reacted with 6FDA and m‐phenylenediamine (MDA) at oligomer concentration from 6.5 to 25.8 mol % to form block copolyimides. Increasing the concentration of the 6FDA‐RTIL oligomer in the block copolyimides resulted in a decrease in the thermal degradation temperature, glass transition temperature and an increase in the density. The gas permeability of the RTIL based block copolyimide decreased but the ideal permeability selectivity for CO₂/CH₄ gas pair increased relative to the pure 6FDA‐MDA. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 4036–4046, 2010     

环境友好型离子液体催化环氧丙烷反应合成丙二醇醚

丙二醇醚类化合物是性能优良的精细化学品,也是环保型高级溶剂.该类化合物具有两个强溶解性功能基团—醚键和羟基,前者具有亲油性,可溶解疏水性物质,后者具有亲水性,可溶解亲水性物质,因而丙二醇醚具有很强的溶解能力,素有"万能溶剂"之称,可广泛应用于涂料、油墨、油漆、印刷、电子化学品、染料、净洗和纺织等行业.丙二醇醚类化合物目前主要由环氧丙烷和低级脂肪醇反应合成,然而,由于环氧丙烷的位阻效应,使其在酸或碱的条件下开环的位置会不同,从而得到不同的醇醚产物.由于碱催化的醇醚产物更加环境友好,因而越来越被人们所关注.工业上丙二醇醚合成多采用传统的强碱性催化剂醇钠以及氢氧化钠,腐蚀性强,产生的废液量大.本文采用环境友好的非卤素离子液体作为催化剂,研究了其催化环氧丙烷醚化合成丙二醇醚的反应特性.本文采用两步法合成了一系列环境友好的醋酸类碱性功能化离子液体,并在温和的条件下将其用于催化环氧丙烷与醇反应合成丙二醇醚.结果表明,该类离子液体可以高效催化该反应的进行.利用紫外-可见光谱测定Hammett指数来表征实验中所用离子液体的碱强度,并构建了离子液体碱性与催化活性之间的关系.结果表明,离子液体的催化性能和其碱性密切相关,随着离子液体碱性的增加,催化活性增强,其中咪唑醋酸类离子液体碱性强于季胺类,表现出优异的催化性能.离子液体的碱性明显弱于NaOH,但却呈现出更优异的催化性能.相同反应条件下,EmimOAc离子液体作为催化剂,PO的转化率分别较NaOH高出20%–30%,选择性略高于NaOH,这可能是由于二者催化机理不同造成的.传统NaOH催化机理的关键步骤是醇在碱性催化剂的作用下去质子化形成电子供体烷氧根离子,促进环氧丙烷的开环加成.而本文提出了离子液体亲电亲核双活化作用机理,即离子液体在阴阳离子之间的氢键和电荷相互作用的共同作用下,促进环氧丙烷开环和醇的去质子化,形成相应的反应中间体.通过电喷雾质谱分析手段检测到了阴阳离子通过协同作用亲电亲核催化过程中的反应中间体,证明了该假设机理的可行性.此外,还考察了催化剂浓度、醇比、反应温度以及醇的空间位阻效应对反应的影响.以EmimOAc催化合成丙二醇丁醚为例,反应的转化率随催化剂浓度的增加而增大,在催化剂添加量1%(催化剂与PO的摩尔比)时,PO转化率达到最大值为98.2%,1-丁氧基-2-丙醇的选择性为86.4%.当正丁醇与环氧丙烷的摩尔比为3时,转化率最高为88.6%,选择性高达94%.该反应为放热反应,最适反应温度约为140 oC,此时转化率高达96.5%.在环氧丙烷和不同的低碳醇合成丙二醇醚的反应中,反应物醇的碳链越短,支链越少,催化反应效率越高.     

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 refolding yield was obtained in 1-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 intramolecular disulfide bonds. For dilution-based refolding of lysozyme, the optimum concentrations of RTILs in refolding buffer were found to be 1.0 M [EMIM][BF4] and 0.5 M [BMIM][MS], respectively. The optimum temperate for dilution-based refolding of lysozyme with RTILs was 4 °C.