绿色溶剂离子液体在化学反应中的应用

离子液体用作化学反应的溶剂，对提高化学反应速率、选择性，或实现催化剂的循环利用及产物分离都具有明显的优势，而且对许多化学反应，离子液体还具有催化功能。这对于开发新的化学工艺，实现绿色化学过程具有重要的意义。本文主要介绍离子液体在化学反应中的应用最新进展及其工业化前景。     

绿色溶剂——离子液体的制备与应用

合成的离子液体已达一百多种，离子液体作为溶剂可用于分离过程，化学反应，特别是催化反应以及电化学等方面，并已取得许多良好的实验结果，离子液体易于循环利用从而减少对环境的污染，被称为绿色溶剂。     

离子液体在生物催化中的应用

近年来,离子液体(ILs)以其独特的优势成为生物催化反应研究的热点,尤其是作为生物催化反应的溶剂或共溶剂的研究更是备受关注.许多酶能在ILs或其形成的两相体系或单相体系中保持催化活性.如目前研究最多的脂肪酶,有多种能在ILs中表现出活性稳定、反应选择性提高、产率提高等优良特性;某些蛋白酶在ILs中稳定性提高,具有酯酶的活性;β-半乳糖苷酶在ILs中的催化产率提高;全细胞在ILs中的催化反应效果也较好;但是也有某些酶,如纤维素酶、某些过氧化物酶等在ILs中活性会降低或丧失.因此有关这一方面的研究还有待进一步深入.     

绿色溶剂离子液体在有机合成中的研究进展

概述了离子液体在有机反应中的研究进展     

绿色溶剂离子液体的性质和应用研究进展

离子液体即在室温或近室温温度下呈液态的完全由离子构成的物质。作为一种绿色溶剂,其具有熔点低、蒸气压小、电化学窗口大、酸性可调及良好的溶解度、粘度和密度等特点。离子液体由于其优良性质在分离、有机合成及催化反应等领域被广泛应用,其对环境友好使得在工业上的应用前景良好。     

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。     

离子液作为反应介质和催化剂的研究进展

近年来的研究发现离子液用作反应介质,在有机反应中显示出反应速率高、选择好、催化剂可回收重复使用等优点,离子液还可直接作为催化剂催化反应;在此,本文将介绍离子液作为反应介质和催化剂的研究成果。     

离子液体支撑液膜应用研究进展

离子液体作为一种新型绿色介质,受到研究学者的广泛关注。离子液体具有不易燃、无味、无污染、无蒸汽压、可循环使用等独特性质,被广泛应用于化学化工过程中。离子液体用于膜分离技术具有不易挥发、稳定性好的特点,近来对离子液体在支撑液膜方面的研究备受关注,离子液体支撑液膜在污染性气体的吸收分离方面具有高选择性、高渗透性等优势,在有机物的分离方面具有分离效果明显、耐用性强等优势,在化学反应方面具有催化效率高、可循环使用等优势,本文介绍了离子液体支撑液膜的常用制备方法和膜基材料的选择,探讨了离子液体支撑液膜的稳定性和分离选择性的影响因素,对离子液体支撑液膜在气体分离、有机物的分离、化学反应等方面的应用研究进行了综述。     

咪唑类离子液体及其在生物催化中的应用

咪唑类离子液体的合成,概括了离子液体中生物催化反应的特点,重点介绍咪唑类离子液体在蛋白酶催化的反应、脂肪酶催化的反应、氧化还原酶催化的反应以及其它酶催化的反应中的应用。     

离子液体支撑液膜分离CO2的研究进展

总结了离子液体支撑液膜分离CO2的研究进展,简要分析了气体在离子液体支撑液膜中的传质机理;介绍了离子液体支撑液膜的制备方法及影响离子液体支撑液膜稳定性的因素;指出了今后用于分离CO2的离子液体支撑液膜的发展方向。     

离子液体在全细胞催化中的应用

离子液体作为一种新型的非水生物催化溶剂,由于其特有的性质有可能取代传统有机溶剂,并在有机化学、食品工业、新能源等领域中得到应用。介绍了离子液体在全细胞催化中的应用,着重介绍了离子液体在全细胞催化合成有机物、生物柴油制备和原位萃取3方面的应用,并阐述了将离子液体应用于全细胞催化所面临的问题。     

离子液体及其在生物催化反应中应用的新进展

综述了室温离子液体的合成方法及其在生物催化反应中的最新应用。     

离子液体在生物催化制备手性化合物中的应用

介绍了离子液体的特性;同时对近几年报道的离子液体对酶及细胞活性影响的研究进行了归纳、总结和分析;详细介绍了近几年报道的有关离子液体在生物催化手性化合物合成中的应用情况,特别是对于水解酶和氧化还原酶催化的反应按反应的类型分别进行了归纳和分析。     

离子液体的工业应用研究进展

离子液体以其特有的性质广受学术界和工业界关注,业已发展成为国际科技的前沿和热点,在诸多领域展示了广阔的应用潜力和前景。本文综述了近二十年来国内外离子液体工业应用进展情况,并对离子液体在化学工程、电化学、高性能添加剂、气体处理、分离分析以及能源领域中的工业化应用现状做了重点介绍。最后对离子液体工业化应用的前景做了展望,并分析了离子液体在实现大规模应用之前应重点解决绿色化、基础理论和成本控制问题。     

Enhancement of activity and selectivity in lipase‐catalyzed transesterification in ionic liquids by the use of additives

BACKGROUND: Seven ionic liquids (ILs) based on 1-alkyl-3-methylimidazolium cation in combination with hexafluorophosphate and bis{(trifluoromethyl)sulfonyl}imide anions were tested as reaction media for lipase-catalyzed transesterification in low water conditions. With the aim of improving the activity and/or selectivity of the lipase, various treatments were applied to ionic liquid media such as equilibration with aqueous solutions of salts, NaHCO₃ or Na₂CO₃, or the addition of a catalytic amount of a non-reactive organic base to the reaction mixture, triethylamine. RESULTS: The treated ionic liquids were shown to be excellent media for lipase-catalyzed ester synthesis by transesterification compared with conventional organic solvents, such as n-hexane. All treatments were found to enhance the synthetic activity of the enzyme, the best results being achieved with the addition of triethylamine. The addition of a catalytic amount of this base to the ILs resulted in a significant increase in both the synthetic activity and selectivity values. For instance, the synthetic activity in [emim⁺][TfN₂⁻] was enhanced more than 12 times and the selectivity increased from 86% to 95% when triethylamine was used. CONCLUSION: These treatments could be easy-to-use approaches to improve the efficiency of enzymatic reactions in ionic liquids when the reaction does not proceed smoothly. Copyright © 2007 Society of Chemical Industry     

离子液体萃取重金属离子的研究进展

离子液体作为一种新型的绿色溶剂,在重金属离子萃取分离方面较传统的有机溶剂有显著的优势。本文系统综述了近年来使用离子液体萃取重金属离子的研究进展,详细讨论了离子液体萃取重金属离子的原理和影响因素,包括螯合剂浓度、萃取时间、萃取温度、离子液体组成、溶液pH值、金属离子初始浓度、干扰离子以及水/离子液体质量比等。进一步介绍了提高离子液体萃取性能的措施以及金属离子的脱除与离子液体的回收状况,以及该萃取方法在废水处理、重金属离子分析和冶金中的研究与应用现状,最后指出其未来发展方向是合成功能化离子液体、提高萃取效率,以实现其工业化应用。     

离子液体的非常规制备技术研究进展

离子液体的大规模应用有赖于其制备技术的不断进步。然而,常规制备方法反应时间长、产品纯化繁琐、不宜规模化等问题,制约着离子液体的工业化应用进程。针对离子液体制备过程的关键环节,综述了目前离子液体非常规制备技术的研究进展,重点介绍了微波、超声波、微波-超声、微反应和STT过程强化制备离子液体的技术研究现状,指出现阶段虽然非常规制备技术取得了重要进展,但是仍然需要通过深入细致的研究,建立完善的理论指导体系,同时还要加快功能化离子液体和绿色化制备技术开发。     

Methods for stabilizing and activating enzymes in ionic liquids—a review

Ionic liquids (ILs) have evolved as a new type of non‐aqueous solvents for biocatalysis, mainly due to their unique and tunable physical properties. A number of recent review papers have described a variety of enzymatic reactions conducted in IL solutions; on the other hand, it is important to systematically analyze methods that have been developed for stabilizing and activating enzymes in ILs. This review discusses the biocatalysis in ILs from two unique aspects (1) factors that impact the enzyme's activity and stability, (2) methods that have been adopted or developed to activate and/or stabilize enzymes in ionic media. Factors that may influence the catalytic performance of enzymes include IL polarity, hydrogen‐bond basicity/anion nucleophilicity, IL network, ion kosmotropicity, viscosity, hydrophobicity, the enzyme dissolution, and surfactant effect. To improve the enzyme's activity and stability in ILs, major methods being explored include the enzyme immobilization (on solid support, sol–gel, or CLEA), physical or covalent attachment to PEG, rinsing with n‐propanol methods (PREP and EPRP), water‐in‐IL microemulsions, IL coating, and the design of enzyme‐compatible ionic solvents. It is exciting to notice that new ILs are being synthesized to be more compatible with enzymes. To utilize the full potential of ILs, it is necessary to further improve these methods for better enzyme compatibility. This is what has been accomplished in the field of biocatalysis in conventional organic solvents. Copyright © 2010 Society of Chemical Industry     

Stability of hydrolase enzymes in ionic liquids

In this work we attempted to evaluate the stability of penicillin G acylase (PGA) from Escherichia coli in their native form and free Candida antarctica lipase B (CaLB) in ionic liquids (ILs) at low water content. The hydrolysis of penicillin G to 6‐aminopenicillanic acid (6‐APA), and phenyl acetic acid (PAA) catalysed by PGA and the synthesis of butyl butyrate from vinyl butyrate and 1‐butanol catalysed by CaLB were chosen as activity tests. The influence of these new solvents on enzyme stability was studied by incubating the enzyme (PGA or CaLB) in ILs based on dialkylimidazolium cations associated with perfluorinated and dicyanamide anions at a given temperature. Stability studies indicate that CaLB and PGA exhibited greater stability in water‐immiscible ILs than in water‐miscible ILs. Specifically, native PGA shows greater stability in IL media than in organic solvents. For example, a half‐life time of 23 h was obtained in 1‐ethyl‐3‐methylimidazolium bis{(trifluoromethyl)sulfonyl}imide, , which was about 2000‐fold higher than that in 2‐propanol. The higher half‐life time of CaLB was observed in (t_1/2 = 84 h).