离子液体的特性及其在生物催化和生物转化中的应用

生物催化反应具有反应条件温和、无环境污染、反应速度快、选择性高等优点,因此成为催化学科的前沿之一.目前已有100多种化学工业生产利用生物催化反应,实验室规模的酶催化更有13000种之多[1].自20世纪80～90年代以来,世界各国的科学家对离子液体(Ionic Liquids,ILs)的研究越来越多,原因是ILs在室温或室温附近温度下呈液态、一般是由有机阳离子和无机阴离子所组成,熔点低、蒸气压小、电化学窗口大、酸性可调及良好的溶解度、粘度、密度等特点,已经或正在有机合成、催化、分离、电化学等领域被广泛应用,并因其对环境友好吸引了工业的兴趣,而且因其绿色环保有望取代传统有机溶剂.     

多孔液体在气体捕集与分离领域的应用

多孔液体是指具有永久性孔隙的液体材料,其将多孔固体的有序规整孔道和液体的流动性等诸多优点相结合,在气体捕集与分离领域表现出巨大的应用潜力,成为新的研究热点。本文首先简单阐述了多孔液体的概念及分类,并总结了多孔液体形成的必要条件;然后分别详细综述了三类多孔液体的合成进展,并阐述了多孔液体在气体捕集与分离方面的应用,着重介绍了近五年的研究进展;最后对其现存的挑战及未来展望进行了总结。     

CO2/离子液体体系热力学性质的分子动力学模拟

超临界CO2和离子液体(ILs)是两种绿色溶剂. 离子液体可以溶解超临界CO2, 而超临界CO2不能溶解离子液体. 由此设计构成的CO2/IL二元系统, 同时具备了超临界CO2和离子液体的许多优点: 既可以降低离子液体的粘度, 还便于相分离, 是新型的耦合绿色溶剂. 其物理化学性质对于设计反应、分离等过程非常重要. 因此, 本文以CO2/IL二元系统为研究对象, 通过选择合适的分子力场和系综, 运用分子动力学(MD)模拟方法研究了CO2/[bmim][PF6]、CO2/[bmim][NO3]等体系的热力学性质. 结果表明, CO2对ILs膨胀度的影响非常小, 当CO2摩尔分数为0.5时, ILs膨胀仅为15%. CO2/ILs的扩散系数远小于CO2膨胀甲醇、乙醇溶液的扩散系数. 随着CO2含量的增加, ILs的扩散系数提高, 粘度显著下降, 表明CO2能有效地改善ILs扩散性, 减小其粘度. 因此CO2可用以改善离子液体溶剂体系的传递特性, 增强反应分离过程在其中的进行.     

聚合物在咪唑类离子液体中的溶解

离子液体（ILs）具有难挥发、热稳定、宽液程和高电导率等独特优点,在聚合物领域中的应用受到越来越多的关注。由于ILs内部的复杂相互作用力,ILs的溶剂化能力还不能像分子溶剂那样有定量的方法来表征,特别是ILs与聚合物的相容性没有一个统一的判据。本文从咪唑基ILs内部的四个主要相互作用力出发,简述了ILs内部的相互作用对...     

含CO2/离子液体系统相行为及其在反应与分离中的应用进展

目前已知的绿色溶剂主要包括超临界流体（Supercritical fluids,SCFs）、离子液体（Ionic liquids,ILs）、二氧化碳膨胀液体（CO₂ expanded liquids, CXLs）、水以及上述溶剂的混合物等。其中,由超临界CO₂（Supercritical CO₂,SCCO₂）与ILs混合而构成的新兴溶剂,因为化学热力学方面的特性,成为近年来研究的热点,未来很有发展前景。本文回顾了目前为止在该领域所开展的工作,总结了影响SCCO₂与IL相行为的主要因素。包括温度、压力、ILs的含水量、ILs的阴离子、ILs的阳离子、ILs的摩尔体积以及助溶剂等。同时分析了ILs/SCCO₂与溶质形成的多元混合物相行为的成因。介绍了ILs/CO₂在萃取、反萃取、膜分离、反胶束、萃取与反应耦合等分离方面的应用。由于传统的单元操作很难满足无污染和对过程集成的要求,因而含有ILs/ SCCO₂的分离反应耦合过程将是未来是实现清洁生产的发展方向。     

离子液体在多孔碳电极上的电化学性能

制备了数种离子液体及离子液体有机溶液电解质,用线性电位扫描法测试了它们的电化学窗口;并通过循环伏安、交流阻抗、电势阶跃等电化学方法,对它们在多孔碳电极中的电化学性能进行了研究.实验结果表明:溶剂对1-乙基-3-甲基咪唑类离子液体有机溶液电解质的电化学窗口有较大的影响.离子液体及离子液体有机溶液电解质在多孔碳电极上的电化学性能与其电导率密切相关,电导率越大,充电时间常数越小,比容量越大;但比容量降低的倍率远小于电导率降低的倍率.     

多孔聚离子液体的合成与应用

聚离子液体(Poly(ionic liquid)s,PIL)是分子结构中含有离子液体结构单元的一类离子聚合物,兼具离子液体小分子的离子电导性和聚合物可加工性能。多孔聚离子液体材料(Porous PILs),结合了多孔材料大比表面积和聚离子液体的导电性及离子交换等特性,在功能高分子材料、电化学响应材料以及能源科学等领域表现出广泛的应用前景。本文综述了多孔聚离子液体的分子设计与合成方法,及其在智能响应材料、水处理、高效催化、多孔碳材料、生物医用材料等领域的潜在应用。     

混合离子液体对聚甲基丙烯酸甲酯分子链缠结及松弛行为的影响

首先通过两步法合成了具有双咪唑环阳离子结构的离子液体(DIL),并将其与单咪唑环离子液体(MIL)进行混合以调控黏度变化,混合离子液体(ILs)的黏度符合对数混合规则且随温度变化呈现Arrhenius型流体行为.进一步通过动态流变、示差扫描量热(DSC)、电化学测试等方法研究了混合离子液体中DIL比例对聚甲基丙烯酸甲酯(PMMA)链缠结和松弛行为的影响,并讨论了PMMA/ILs体系热稳定性、玻璃化转变及离子电导率等的变化.结果表明,DIL独特的双咪唑环结构可与PMMA分子形成更多相互作用位点,从而导致凝聚缠结的形成,很大程度上限制了PMMA分子链的运动和松弛.随DIL含量增加,PMMA/ILs体系的松弛时间、热分解温度、玻璃化转变温度等参数均呈增大趋势,但其离子电导率有所损失,这与DIL较大的分子尺寸和运动能力有关.     

胆碱类低共熔溶剂的物性及应用

作为一种新型的离子液体,胆碱类低共熔溶剂具有相比于其他离子液体更为突出的特点,如低毒、生物可降解、价格低廉等,这些特点使得此类离子液体在绿色化学和工程化学中受到越来越多的关注。本文分析了胆碱类低共熔溶剂的凝固点、熔点、溶解度、黏度、表面张力、电导率等物性随温度、组成、水分等因素的变化及理论预测模型,并介绍了胆碱类低共熔溶剂在润滑、功能材料制备、电化学、有机合成及生物质催化转化等方面的潜在应用。最后就胆碱类低共熔溶剂研究及应用中存在的问题及难点对其前景做出展望。     

基于离子液体的炭材料制备、改性及应用

离子液体因其熔点低、液态温域宽、蒸气压低、热稳定性高、电导率高、电化学窗口宽、结构可设计及对许多化合物的亲和性等系列性能而引起人们广泛关注。离子液体在炭材料制备、改性领域展示出了良好的前景及巨大的应用潜力,可直接作为碳源,经过高温炭化实现杂原子掺杂制备多孔炭材料;离子液体也可充当反应介质和致孔剂,将生物质转化为多孔炭材料;此外,由于离子液体与炭材料相容性较好,可以用于多孔炭材料改性制备炭复合材料。基于离子液体的炭材料在电催化、超级电容器、吸附分离及生物医学等领域具有潜在的应用价值。本文总结了基于离子液体炭材料的制备、改性及应用最新研究进展,并着重介绍了其在能源和环境相关领域的应用。     

Transforming Porous Organic Cages into Porous Ionic Liquids via a Supramolecular Complexation Strategy

Porous liquids are a type of porous materials that engineer permanent porosity into unique flowing liquids, exhibiting promising functionalities for a variety of applications. Here a Type I porous liquid is synthesized by transforming porous organic cages into porous ionic liquids via a supramolecular complexation strategy. Simple physical mixing of 18‐crown‐6 with task‐specific anionic porous organic cages affords a porous ionic liquid with anionic porous organic cages as the anionic parts and 18‐crown‐6/potassium ion complexes as the cationic parts. In contrast, mixing of 15‐crown‐5 and anionic porous organic cages in a 2:1 ratio gives only solids, while the addition of excess 15‐crown‐5 affords a Type II porous liquid. The permanent porosity in the cage‐based porous liquids has been also confirmed by molecular simulation, positron (e⁺) annihilation lifetime spectroscopy, and enhanced gas sorption capacity compared with pure crown ethers.     

功能化离子液体的制备及其在合成中的应用

功能化离子液体;手性离子液体;酸性离子液体     

An ionothermal synthetic approach to porous polyoxometalate-based metal-organic frameworks

Pretty porous POMs: Ionothermal synthesis was applied to prepare porous POM-based open frameworks. The structural integrity remains unchanged until 300?°C; most importantly, the bulky tetrabutylammonium cations within their nanosized channels can be replaced by transition-metal ions through a cation-exchange process, and subsequent gas adsorption measurements confirm their permanent porosity.     

Experimental nibble for computational chemists: On the construction and CO2 capture by different zeolite imidazole ester framework-8 and ionic

The combination of zeolitic imidazolate framework-8 (ZIF-8) and ionic liquids (ILs) to create porous ionic liquids (PILs) is highly significant for efficient carbon dioxide (CO₂) capture and the advancement of carbon capture, utilization, and storage (CCUS) technologies. To further investigate the CO₂ capture characteristics of different PILs, two different-sized ZIF-8 structures and two functionalized ILs were prepared. Additionally, the enhancement factor of the reaction process was calculated using the dual-film theory and mass transfer coefficient. The results demonstrated that the original [PMIm]Cl had low CO₂ absorption capacity at ambient temperature and pressure, whereas the functionalized ILs had a maximum CO₂ capture capacity of approximately .31 mol/mol, with the 20 wt% concentration of tetraethylene pentamine-2-methylimidazole ([TEP][MIm]) exhibiting the highest CO₂ capture capacity of around 1.93 mol/mol. The synthesized PILs demonstrated a maximum CO₂ capture capacity of approximately 2.22 and 2.16 mol/mol at 20 and 10 wt% ionic concentrations, respectively, with a porous ionic liquid addition of 1.0/100 g. The corresponding enhancement factors were 1.53 and 1.59, respectively. These findings have significant implications for CCUS technology.     

Applications of functionalized ionic liquids

Recent developments of the synthesis and applications of functionalized ionic liquids (including dual-functionalized ionic liquids) have been highlighted in this review. Ionic liquids are at-tracting attention as alternative solvents in green chemistry, but as more functionalized ILs are pre-pared, a greater number of applications in increasingly diverse fields are found.     

Sugar-Based Ionic Liquids: Multifaceted Challenges and Intriguing Potential

Carbohydrates represent a promising option in transitioning from oil-based chemical resources to renewable ones, with the goal of developing chemistries for a sustainable future. Cellulose, hemicellulose, and largely available monosaccharides already provide useful chemical building blocks, so-called platform chemicals, such as levulinic acid and hydroxymethyl furfural, as well as solvents like cyrene or gamma-valerolactone. Therefore, there is great anticipation for novel applications involving materials and chemicals derived from sugars. In the field of ionic liquids (ILs), sugar-based ILs have been overlooked for a long time, mainly on account of their multistep demanding preparation. However, exploring new strategies for accessing sugar-based ILs, their study, and their exploitation, are attracting increasing interest. This is due to the growing concerns about the negative (eco)toxicity profile of most ILs in conjunction with their non-sustainable nature. In the present review, a literature survey concerning the development of sugar-based ILs since 2011 is presented. Their preparation strategies and thermal behavior analyses, sorted by sugar type, make up the first two sections with the intention to provide the reader with a useful guide. A final overview of the potential applications of sugar-based ILs and their future perspectives complement the present analysis.     

High‐Performance Polymers for Membrane CO2/N2 Separation

This Concept examines strategies to design advanced polymers with high CO₂ permeability and high CO₂/N₂ selectivity, which are the key to the success of membrane technology for CO₂ capture from fossil fuel‐fired power plants. Specifically, polymers with enhanced CO₂ solubility and thus CO₂/N₂ selectivity are designed by incorporating CO₂‐philic groups in polymers such as poly(ethylene oxide)‐containing polymers and poly(ionic liquids); polymers with enhanced CO₂ diffusivity and thus CO₂ permeability are designed with contorted rigid polymer chains to obtain high free volume, such as polymers with intrinsic microporosity and thermally rearranged polymers. The underlying rationales for materials design are discussed and polymers with promising CO₂/N₂ separation properties for CO₂ capture from flue gas are highlighted.     

Synthesis of Two-Dimensional Covalent Organic Frameworks in Ionic Liquids

Two-dimensional covalent organic frameworks were synthesized in high yields by polycondensation in nonvolatile ionic liquids. The resulting crystallites are highly porous and exhibit exceptional capability of removing bisphenol A from water. The one reported is a general method to synthesize microporous and mesoporous frameworks, it allows to achieve regular macroscopic shapes, and it is effective in a wide range of reaction temperatures.