聚离子液体材料在分离科学中的研究进展

离子液体作为新型离子化试剂,具有诸多优越的物理化学性质,比如:良好的溶解性、导电性、热稳定性、生物相容性及低蒸气压和不易燃等特点,近年来在分析化学领域得到广泛关注。聚离子液体材料结合了离子液体和聚合物的双重性质,已经成为分离科学研究的前沿领域。本文详细讨论了离子液体与目标物之间的多种作用机制,比如亲/疏水作用、氢键作用、离子交换、π - π 堆积及静电吸附作用等等,总结了聚离子液体材料在固相萃取、液相色谱、气相色谱、毛细管电泳及毛细管电色谱等领域的研究进展;最后,对聚离子液体材料的发展前景进行了展望。     

有机-无机杂化聚离子液体材料制备及其对染料吸附性能的评价

以烯丙基三乙氧基硅烷与1-乙烯基-3-辛基咪唑溴盐离子液体为单体通过自由基聚合及溶胶-凝胶制备了有机-无机杂化聚离子液体材料。通过红外光谱和扫描电镜对所制备的杂化聚离子液体材料进行了表征,并考察了其对柠檬黄、日落黄、苋菜红以及诱惑红等常见染料的吸附性能。研究结果表明:所制备的聚离子液体材料对日落黄和诱惑红具有优异的吸附性能,其吸附容量分别为29.20和86.17 mg/g;当吸附时间为5 min时,该材料对诱惑红和日落黄的吸附分别达到平衡时吸附量的87.5%和72.8%,显示了较快的吸附速率。     

离子液体固载型功能材料的应用研究进展

随着人们对生物质能源和绿色清洁化学过程越来越重视,离子液体因其稳定性、低粘度和高电导率等优良性能,成为20世纪90年代初研究团队广泛关注的一类新型绿色溶剂,对其研究内容和应用领域也日趋完善和丰富,特别是在催化反应、电化学、材料化学以及生物质的前处理等领域的发展.对于离子液体的应用研究主要存在着用量庞大、价格昂贵、催化剂不易分离和提纯过程烦琐等缺陷.所以,近年来许多学者尝试通过吸附或者接枝固载化的方法,将离子液体固载于无机多孔材料或者有机高分子材料上,把离子液体的特性转移到多相固体催化剂上,可应用于固定床连续化、封闭化反应.本文对离子液体固载技术的诞生及发展做了详细地梳理,并将离子液体固载技术的应用领域做了多角度地总结,根据离子液体类型的不同,主要是作为催化剂应用于反应催化领域;根据固态载体的不同,主要是作为功能材料应用于吸附分离领域.     

聚季铵盐离子液体材料制备及其对蛋白质吸附性能评价

通过一步合成法制备了两种可聚合季铵盐离子液体功能单体,并通过沉淀聚合法合成了相应的聚离子液体聚合物。对产物进行了核磁共振、扫描电镜、热重分析等表征。结果表明:所制备的两种材料粒径均匀,约为600 nm的椭球形颗粒,颗粒之间有相互粘连。通过对牛血清白蛋白(BSA)、卵清蛋白(OVA)、牛血红蛋白(BHb)、溶菌酶(Lys)、胰蛋白酶(Try)5种蛋白质的吸附性能实验,考察了聚季铵盐离子液体材料对蛋白质的吸附性能。考察结果表明:两种聚离子液体材料均对蛋白质具有一定的吸附性能。其中以4-乙烯基苄氯季铵盐离子液体为功能单体制备的聚离子液体材料对胰蛋白酶的吸附性能最好,是一种具有良好应用前景的材料。     

离子液体中制备无机材料

离子液体作为潜在的“绿色”溶剂,具有许多传统溶剂无法比拟的优异性能,在有机合成、催化、液液分离和萃取等领域引起了广泛的研究。而在离子液体领域无机材料的制备是一个较新的发展分支,现已利用其合成出多种具有独特结构和性能的无机材料。本文就离子液体在无机材料制备方面的应用及发展趋势进行了综述。目前,对于制备无机材料,离子液体主要是作为电解液、表面活性剂或溶剂,本文介绍了其在应用中的优缺点,并指出该领域未来的发展趋势是离子热合成和集模板-溶剂-反应物于一身的离子液体反应。     

离子液体功能高分子

离子液体功能高分子(ILFPs)是含离子液体结构的有机高分子,主要由不饱和单体聚合得到.此类高分子结合了离子液体所具有的独特性质,成为目前研究的热点.本文总结了近几年国内外有关ILFPs的最新研究成果,将现有的几十种ILFPs按与高分子链直接相连的离子的种类归为聚阳离子型、聚阴离子型和内盐型3类,介绍了各类ILFPs的合成方法及影响Tg大小的各种结构因素.此外,本文重点对ILFPs在聚合物电解质、表面活性剂、催化剂、生物酶载体及气体吸附剂等方面的应用进行了综述.最后提出了ILFPs的研究中尚待解决的诸如品种不多、结构表征不详等问题及今后可能的发展方向.     

离子液体在锂离子电池中的应用研究进展

离子液体具有蒸汽压低、热稳定性好、不易挥发、溶解能力强、环境友好、电化学稳定窗口和液程范围宽等优点,在锂离子电池领域应用前景广泛。本文按照离子液体作为电解质溶剂、与传统电解质复配或与聚合物电解质结合的应用方式,总结其对电池的安全性和热稳定性的影响,并综述了近年来离子液体在锂离子电池电解质中的应用研究进展。     

室温离子液体电解质与锂离子电池碳负极材料的相容性

室温离子液体电解质与碳负极材料间的相容性是其应用于锂离子电池的关键问题之一.本文总结了室温离子液体电解质体系与碳负极材料相容性的研究现状和微观机制,阐述了不同种类的室温离子液体与碳负极材料相容性的规律和存在的问题以及改善方法.     

聚离子液体的合成及应用

聚离子液体(PILs)是在重复单元上具有阴、阳离子电解质基团的聚合物。此类聚合物结合了离子液体和聚合物的一些性质,近年来在高分子化学和材料科学等领域受到广泛关注。本文将聚离子液体划分为聚阳离子型离子液体、聚阴离子型离子液体、聚两性型离子液体和共聚型离子液体四类并介绍了聚离子液体的性质及各类聚离子液体的合成。此外,本文还对聚离子液体在有机分散剂、纳米复合材料、电化学、吸附剂和分离等方面的应用进行了综述。     

原位聚合制备的离子液体/聚合物电解质的研究

采用原位聚合制备出新型的BMIPF6/PMMA聚合物电解质透明弹性膜. 研究结果表明, BMIPF6/PMMA聚合物电解质体系在305 ℃时仍具有较好的热稳定性, 其安全性能优于含有机溶剂的传统非水电解质体系. 随着离子液体含量的增加, 其玻璃化转变温度逐渐减小, 离子电导率升高; 且离子电导率与温度的关系服从VTF方程. 其中, 当BMIPF6的质量分数为50%时, 该聚合物电解质的室温离子电导率高达0.15 mS/cm.     

Accelerating Crystallization of Open Organic Materials by Poly(ionic liquid)s

The capability to significantly shorten the synthetic period of a broad spectrum of open organic materials presents an enticing prospect for materials processing and applications. Herein we discovered 1,2,4-triazolium poly(ionic liquid)s (PILs) could serve as a universal additive to accelerate by at least one order of magnitude the growth rate of representative imine-linked crystalline open organics, including organic cages, covalent organic frameworks (COFs), and macrocycles. This phenomenon results from the active C5-protons in poly(1,2,4-triazolium)s that catalyze the formation of imine bonds, and the simultaneous salting-out effect (induced precipitation by decreasing solubility) that PILs exert on these crystallizing species.     

Just Add Salt: A Mass Spectrometric Analysis Method for Imaging Anion‐Exchanged Poly(Ionic Liquid)s

We report the first mass spectrometric analysis of poly(ionic liquid)s (PILs) containing weakly coordinating anions introduced by a fast, simple, and quantitative postmodification method on the example of the hydrophilic, well‐defined poly(vinylbenzylpyridinium chloride) p([VBPy]Cl) species, analyzed with an in‐source collision induced dissociation‐Orbitrap mass spectrometry (MS) protocol. Using the MS approach allows for the precise structural elucidation of ion‐exchanged p([VBPy]Cl) utilizing AgX (X = NO₃⁻, CF₃CO₂⁻, BF₄⁻) salts. The anion exchange is shown to be quantitative – without observing residual chlorinated PIL – on rapid time scales, using only filtration as a standard procedure during sample preparation. In addition, the influence of weakly coordinating anions on the ionization behavior of PILs is studied in detail.

     

Accelerated Solvent‐ and Catalyst‐Free Synthesis of 1,2,3‐Triazolium‐Based Poly(Ionic Liquid)s

A straightforward and expeditious monotopic approach for the preparation of 1,2,3‐triazolium‐based poly(ionic liquids) (TPILs) is reported. It is based on the solvent‐ and catalyst‐free polyaddition of an α‐azide‐ω‐alkyne monomer in the presence of methyl iodide or N‐methyl bis[(trifluoromethyl)sulfonyl]imide alkylating agents. Poly(1,2,3‐triazole)s generated in bulk or by thermal azide–alkyne cycloaddition (AAC) are quaternized in‐situ to afford TPILs composed of 1,3,4‐ and 1,3,5‐trisubstituted 1,2,3‐triazolium units. The physical and ion‐conducting properties of the prepared samples are compared with the TPILs composed solely of 1,3,4‐trisubstituted 1,2,3‐triazolium units obtained through a multistep approach involving copper(I)‐catalyzed AAC polyaddition, quaternization of the 1,2,3‐triazole groups, and anion metathesis. TPILs obtained through the monotopic approach display thermal stabilities and ionic conductivities comparable to their pure regioisomeric analogues.

     

Porous Poly(Ionic Liquid) Membranes as Efficient and Recyclable Absorbents for Heavy Metal Ions

Heavy metal ion pollution has become a serious environmental problem. Herein, this study reports the synthesis of poly(ionic liquid) (PIL) membranes via in situ photo‐crosslinking of vinyl imidazole with both hydrophilic and hydrophobic ionic liquid monomers. The resultant amphiphilic polymer membranes are porous and exhibit high absorption capacity of metal ions (including Hg²⁺, Pb²⁺, Cu²⁺, Cd²⁺, and Zn²⁺) in both high (1000 mg L⁻¹) and low (10 mg L⁻¹) concentration metal ion solutions. These metal ionic absorption membranes are easily regenerated in acid solution and can be reused without significant decreases of absorption capacity after many cycles. These PIL membranes may have potential applications as eco‐friendly and safe heavy metal ion removal materials.

     

The Synthesis of Poly(Vinyl Alcohol) Grafted with Fluorinated Protic Ionic Liquids Containing Sulfo Functional Groups

There has been an ongoing need to develop polymer materials with increased performance as proton exchange membranes (PEMs) for middle- and high-temperature fuel cells. Poly(vinyl alcohol) (PVA) is a highly hydrophilic and chemically stable polymer bearing hydroxyl groups, which can be further altered. Protic ionic liquids (proticILs) have been found to be an effective modifying polymer agent used as a proton carrier providing PEMs’ desirable proton conductivity at high temperatures and under anhydrous conditions. In this study, the novel synthesis route of PVA grafted with fluorinated protic ionic liquids bearing sulfo groups (–SO₃H) was elaborated. The polymer functionalization with fluorinated proticILs was achieved by the following approaches: (i) the PVA acylation and subsequent reaction with fluorinated sultones and (ii) free-radical polymerization reaction of vinyl acetate derivatives modified with 1-methylimidazole and sultones. These modifications resulted in the PVA being chemically modified with ionic liquids of protic character. The successfully grafted PVA has been characterized using ¹H, ¹⁹F, and ¹³C-NMR and FTIR-ATR. The presented synthesis route is a novel approach to PVA functionalization with imidazole-based fluorinated ionic liquids with sulfo groups.     

Stable Covalently Photo‐Crosslinked Poly(Ionic Liquid) Membrane with Gradient Pore Size

Porous polyelectrolyte membranes stable in a highly ionic environment are obtained by covalent crosslinking of an imidazolium‐based poly(ionic liquid). The crosslinking reaction involves the UV light‐induced thiol–ene (click) chemistry, and the phase separation, occurring during the crosslinking step, generates a fully interconnected porous structure in the membrane. The porosity is on the order of the micrometer scale and the membrane shows a gradient of pore size across the membrane cross‐section. The membrane can separate polystyrene latex particles of different size and undergoes actuation in contact with acetone due to the asymmetric porous structure.     

Supported Poly(Ionic Liquid)-Heteropolyacid Based Materials for Heterogeneous Catalytic Fructose Dehydration in Aqueous Medium

Two sets of four different supported catalyst materials were prepared. One set was obtained by polymerization of a bis-vinylimidazolium salt, which formed a poly(ionic liquid) coating on SiO₂, TiO₂, boron nitride BN, and carbon nitride C₃N₄. The other set was, instead, obtained by immobilizing Keggin heteropolyacid H₃PW₁₂O₄₀ onto poly-imidazolium functionalized materials. All the catalysts, including the bare supports, were subjected to physical and chemical characterization by XRD, SEM, Specific Surface Area and pore size measurements, TGA, FTIR, and acidity-basicity measurements. The catalytic activity of the materials was tested versus the fructose dehydration in water solution at two different sugar initial concentrations (0.3 and 1 M). Tests lasted 3 h with an amount of catalyst of 2 g∙L⁻¹. The presence of the poly-imidazolium on the surface of the supports increased the catalytic conversion of fructose to 5-hydroxymethylfurfural (the most abundant compound obtained) and was further improved by the contemporary presence of the heteropolyacid, at least for the highest initial fructose concentration. In the latter conditions, the highest yield of 5-hydroxymethylfurfural (>40%) was also obtained.