离子液体在萃取分离中的应用研究进展

室温离子液体作为一种新型绿色溶剂,具有液程宽、几乎不挥发、溶解能力强及结构可调等独特的物理化学性质,近年来逐渐被人们认识了解,它在各个领域的应用也得到了初步的发展.本文重点概述了离子液体在萃取分离金属离子方面的研究进展,并对离子液体萃取分离有机物和生物分子的研究作了简要介绍.引用文献54篇.     

离子液体在蛋白质萃取分离中的应用

离子液体具有独特的物化性质如热稳定性好、不挥发、不易燃和良好的生物兼容性,近年来作为传统有机溶剂的替代物在有机合成、电化学、催化和萃取分离等领域得到了广泛应用。本文简要综述了以离子液体为媒介的萃取体系在蛋白质分离富集和分析中的相关研究和应用进展,包括辅助萃取体系、直接萃取体系、双水相萃取体系、微乳萃取体系、结晶体系和基于离子液体的固相萃取体系等。     

离子液体在萃取技术中的应用

萃取是化学领域应用最广泛的一种单元操作。随着对离子液体研究的不断深入,离子液体以其低毒、低挥发以及可设计等特性,作为环境友好溶剂,在苯系有机物、农药残留、天然有机物、氨基酸、蛋白质、DNA以及金属离子等的萃取、检测技术方面的应用取得了一定的进展,如液液萃取、液相微量萃取、分散相液液微量萃取、固相微量萃取以及含水两相萃取等分离技术中不断有关于离子液体应用的报道,有的甚至取得了非常好的研究成果。本文就离子液体在萃取技术方面的应用,综述了近期国内外的研究进展,探讨了当前存在的问题及研究方向,展望了其应用前景。     

离子液基萃取金属离子的研究进展

室温离子液体作为一种新型绿色溶剂,因其具有不挥发、不易燃等重要特性,故近年来在各种金属离子液/液萃取领域的应用日益受到关注。本文系统评述了离子液基萃取金属离子的分配规律、萃取机理、缺陷和克服方法,并展望了该分离方法在环境分析化学领域的应用前景。     

室温离子液体混合物的相平衡研究进展

室温离子液体混合物的相平衡数据是设计和优化涉及离子液体的化学反应与分离工程的重要基础。本文综述了近年来室温离子液体混合物，特别是室温离子液体＋有机物体系的气－液平衡、液－液平衡和固－液平衡的研究进展，总结了这些混合物相行为的基本热力学规律以及对萃取分离工程的指导作用。     

分散液液微萃取技术的研究进展

分散液液微萃取是一种基于传统液液萃取的新型样品前处理技术。该文以分散液液微萃取技术中萃取剂的筛选为出发点,综述了低密度萃取剂、辅助萃取剂、反萃取剂和离子液体等低毒性萃取剂在该技术中的应用,以及应用自制装置、溶剂去乳化、悬浮萃取剂固化,辅助萃取,反萃取和离子液体-分散液液微萃取等萃取模式;并简要评述了该技术与液液萃取、固相萃取、固相微萃取、分散固相萃取、基质固相分散萃取、超临界流体萃取、超声辅助萃取等其他样品前处理技术的联用特性。     

金属检测中新型前处理技术研究进展及应用

精准检测环境和食品中金属含量对环境保护和人体健康至关重要.样品的准备环节是造成样品损失和二次污染的关键步骤, 因此合适的前处理方法可以提高金属分析的选择性和灵敏度.从液相萃取和非液相萃取新技术两方面综述了浊点萃取、离子液体、超分子溶剂-分散液液微萃取、顶空固相微萃取技术、超临界流体萃取特点及在复杂样品前处理中的应用和研究进展, 并对其未来发展方向进行了展望.     

金属离子提取的支撑型液膜稳定性:膜材料研究进展

支撑液膜是一种结合膜材料与萃取体系的高效率分离技术.然而在使用过程中,溶剂与萃取载体从多孔支撑体中流失和多孔膜材料在有机相载体中不稳定,导致支撑液膜通量的衰减或选择性降低,支撑液膜表现为不稳定,目前尚未见工业化的成功案例.本文简要介绍了支撑液膜不稳定机理,从膜材料角度,综述了提高支撑液膜稳定性的方法.重点介绍了液膜凝胶...     

离子液体表/界面性质与结构

离子液体与气体、溶剂等物质组成的多相体系为吸收、萃取、两相催化等技术的发展提供了新的平台。离子液体的表/界面性质与结构是含离子液体多相体系的重要科学问题,可在介观尺度下显著影响多相体系反应和分离过程的效率。近年来,离子液体表/界面性质和结构的研究得到了广泛的关注。本文综述了离子液体及其与水、有机溶剂组成的混合物的表/界面张力及结构研究进展,介绍了现有的研究方法、研究对象与研究成果,归纳了离子液体及其混合物表/界面张力及结构的变化规律,分析了表/界面结构与表/界面张力之间的关系,探讨了离子液体表/界面研究存在的问题和未来的发展方向。     

离子液体在微萃取技术中的应用

离子液体是在室温或近于室温下呈液态的熔盐体系,由特定阳离子和阴离子构成。与传统的液态物质相比,离子液体几乎没有蒸气压、不易挥发、能溶解许多无机物和有机物。在样品前处理技术中得到了广泛的应用。微萃取技术是一种简便快速、提取效率高、溶剂用量少、环境友好的样品前处理技术。本文综述了离子液体在微萃取技术(液相微萃取和固相微萃取)中的应用。     

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.     

离子液体固定化材料在固相萃取中的应用研究进展

离子液体是由阴、阳离子组成的低温熔融盐,几乎没有蒸汽压,具有稳定性好、溶解能力强、结构可设计、导电性好等优良性能。离子液体作为一种广受关注的新型“绿色溶剂”,具有代替传统有机溶剂的潜力,其制备方法和应用范围研究日趋完善和多样,已广泛应用于催化化学、光电化学、材料化学和分析化学等领域。离子液体通过功能化导向设计后,可以将羟基、氨基、羧基、氰基等活性基团键合在离子液体结构上,促使其更加易于与目标分子通过生成π-π键、氢键、离子键和范德华力等而产生相互作用,更加易于发生固定化反应。将离子液体负载到固体载体材料进行固定化后,新型材料既可以减少离子液体的流失,同时保留了离子液体和固体载体的独特性能,具有富集效率高、吸附容量高、稳定性好、识别位点多、萃取选择性强、离子液体利用率高等特点,近年来,在有机小分子固相萃取分离研究中应用广泛。该文从离子液体与硅胶、分子筛、分子印迹聚合物、氧化石墨烯、磁性材料等固体载体的固定化研究情况入手,综述了离子液体固定化材料在固相萃取分离中的应用情况,涉及的目标分离物质包括生物碱类、黄酮类、多酚类等天然活性成分,以及常见药物分子、有机农药等有机小分子化合物,系统地介绍了离子液体与多种载体固定化的性质、应用和分离机制。离子液体的引入,增加了复合材料的活性位点分布和吸附容量,离子液体固定化材料的吸附效率与离子液体种类、吸附材料用量、样品溶液浓度、吸附温度、pH值、洗脱溶剂类型、用量及流速等因素有关。该文探讨了离子液体结构相对单一、相关基础理论研究相对薄弱、复杂基质萃取程度不理想等问题,并提出相应的解决思路,以期为离子液体固定化材料在复杂基质中目标分子分离分析方面的应用提供借鉴和参考。     

Studies on Liquid/liquid Extraction of Copper Ion with Room Temperature Ionic Liquid

Room temperature ionic liquids are regarded as “Green solvents” for their nonvolatile and thermally stable properties. They are employed to replace traditional volatile organic solvents in organic synthesis, solvent extraction, and electrochemistry. In this work, a water immiscible room temperature ionic liquid, 1‐butyl‐3‐methylimidazolium hexafluorophosphate [C₄mim][PF₆], was used as an alternative solvent for liquid/liquid extraction of copper ions. Metal chelators, including dithizone, 8‐hydroxyquinoline, and 1‐(2‐pyridylazo)‐2‐naphthol, were employed to form neutral metal‐chelate complexes with copper ions so that copper ions were extracted from aqueous solution into [C₄mim][PF₆]. The parameters that affect the extraction of copper ions with this biphasic system were investigated. The extraction behavior in this novel biphasic system is shown to be consistent with that of traditional solvents. For example, the extraction with this biphasic system is strongly pH dependent. So, the extraction efficiency of coppers ion from an aqueous phase can be manipulated by tailoring the pH value of the extraction system. Hence, the extraction, separation and preconcentraction of copper ions can be accomplished by controlling the pH value of the extraction system. It appears that the use of ionic liquid as an alternate solvent system in liquid/liquid extraction of copper ions is very promising.     

Ionic Liquids as Mobile Phase Additives for Separation of Nucleotides in High-Performance Liquid Chromatography

Ionic liquids are a type of salts that are liquid at low temperature (＜100℃). Because of their some special properties, they have been widely used as new “green solvents” for many chemical reactions and liquid-liquid extraction in the past several years. In this paper, a new method for the separation of nucleotides is developed and the essential feature of the method is that 1-alkyl-3-methylimidazolium salts are used as mobile phase additives, resulting in a baseline separation of nucleotides without need of gradient elution and need of organic solvent addition as currently used in RP-HPLC. This study shows the potential application of ionic liquids as mobile phase additives in reversed-phase liquid chromatograohy.     

Use of supercritical fluids in inorganic analysis

The possibilities, advantages, shortcomings, and prospects of using supercritical fluids for separating and extracting metal complexes with organic reagents are considered. The theoretical bases of supercritical fluid chromatography and factors influencing the separation of metal complexes (nature of the organic reagent, solubility of reagents and complexes in a supercritical fluid, type of column, motionless phase, addition of a modifier into the mobile phase, and the test solvent) are discussed. The processes occurring in complexes during chromatography are discussed. The bases of supercritical fluid extraction and factors influencing extraction of metals (nature and solubility in a supercritical fluid of an organic reagent and complexes; concentration and ways of introducing the reagent into the system; addition of the modifier, water, and surfactants; the collector; and the matrix) are considered. The possibilities of methods for determining metals in various objects are shown.     

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。     

Selective separation of aromatic hydrocarbons through supported liquid membranes based on ionic liquids

Ionic liquids are emerging as alternative solvents for volatile organic compounds traditionally used in liquid–liquid extraction and liquid membrane separation. In this paper, we examine whether room-temperature ionic liquids as a membrane solution can be utilized for hydrocarbon separation by using a supported liquid membrane. Aromatic hydrocarbons, benzene, toluene and p-xylene were successfully transported through the membrane based on the ionic liquids. Although the permeation rates through the membrane based on the ionic liquids were less than those of water, the selectivity of aromatic hydrocarbons was greatly improved. The maximum selectivity to heptane was obtained using benzene in the aromatic permeation and 1-n-butyl-3-methylimidazolium hexafluorophosphate in the liquid membrane phase.     

Room temperature ionic liquid as a novel medium for liquid/liquid extraction of metal ions

Room temperature ionic liquids (RTILs) have been used as novel solvents to replace traditional volatile organic solvents in organic synthesis, solvent extraction, and electrochemistry. The hydrophobic character and water immiscibility of certain ionic liquids allow their use in solvent extraction of hydrophobic compounds. In this work, a typical room temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate [C₄mim][PF₆], was used as an alternative solvent to study liquid/liquid extraction of heavy metal ions. Dithizone was employed as a metal chelator to form neutral metal-dithizone complexes with heavy metal ions to extract metal ions from aqueous solution into [C₄mim][PF₆]. This extraction is possible due to the high distribution ratios of the metal complexes between [C₄mim][PF₆] and aqueous phase. Since the distribution ratios of metal dithiozonates between [C₄mim][PF₆] and aqueous phase are strongly pH dependent, the extraction efficiencies of metal complexes can be manipulated by tailoring the pH value of the extraction system. Hence, the extraction, separation, and preconcentraction of heavy metal ions with the biphasic system of [C₄mim][PF₆] and aqueous phase can be achieved by controlling the pH value of the extraction system. Preliminary results indicate that the use of [C₄mim][PF₆] as an alternate solvent to replace traditional organic solvents in liquid/liquid extraction of heavy metal ions is very promising.     

Osmium catalyzed asymmetric dihydroxylation of methyl trans-cinnamate in ionic liquids, followed by supercritical CO2 product recovery

In this work, osmium-catalyzed asymmetric dihydroxylation (AD) of methyl trans-cinnamate was studied. Osmium and chiral ligand catalysts were immobilized in ionic liquid only, without any other reaction solvents, while the recovery of the product was performed by extraction with supercritical CO₂, and compared with results obtained by extractions with organic solvents such as hexane and diethyl ether. In supercritical CO₂ extraction experiments, optimal extraction pressure was found and ionic liquid chosen, so that the highest reaction yields coupled with lowest osmium content in the crude product can be achieved. Finally, recycle experiments of the same (ionic liquid + catalytic system) mixture were successfully conducted. Application of ionic liquids and supercritical CO₂ in osmium catalyzed AD allows for the isolation of the diol basically without contamination with osmium, in high yield and enantiomeric excess, and it makes possible the efficient reuse of ionic liquid solvent and the catalytic system.     

Room temperature ionic liquids and their mixtures—a review

Room temperature ionic liquids are salts that are liquid at room temperature and their use as catalysts and catalytic support has been studied extensively. They are also being considered as “green solvents” for various separation processes. Recent measurements reported on the properties of pure ionic liquids and their mixtures, including gas and liquid solubility in common organic solvents will be reviewed. While some property values are in good agreement, some show large differences. These values will be compared and reasons for the discrepancies will be conjectured. Since traditional approaches to predicting the properties of fluid liquids require extensive LLE and VLE measurements, alternative predictive methods need to be explored. The predictions of the properties of mixtures of ionic liquids using COSMOtherm, an approach based on unimolecular quantum chemical calculations of the individual molecules, will be presented.