Sustainable Processes Employing Ionic Liquids for Secondary Alcohols Separation

Secondary chiral alcohols are very attractive intermediates in organic synthesis of pharmaceutical and the fine-chemical industries. The processes employing ionic liquids to obtain enantiomers of secondary alcohols have become sustainable. Furthermore, physico-chemical properties of ionic liquids opened new possibilities to design “solvent free” processes for the resolution of racemic secondary alcohols. This review is aimed to highlight some of the most important achievements in resolution of secondary alcohols.     

超临界CO2/离子液体体系

超临界CO2和离子液体是两种具有优异性能的绿色化学试剂,本文介绍了将两者结合反应,分离体系的物化性质和多种绿色化学过程。利用超临界CO2可以广泛地萃取离子液体中的不挥发性化合物而不导致离子液体及其中催化剂的流失,在加氢、醛化、甲酰化等反应,分离过程中的应用表明,过程具有很好的反应分离特性和环境友好性,应用前景广阔。     

离子液体在CO_2捕集中的应用进展

离子液体具有蒸汽压极低、热稳定性好、热容低和可以根据目标需求进行设计等特性,能克服传统CO2捕集工艺的诸多不足,因而成为目前CO2捕集溶剂的研究热点。本文主要综述了普通离子液体、功能化离子液体、支撑型离子液体膜、聚合型离子液体和离子液体复配溶液在CO2捕集方面的应用研究进展,评述了各种方法的优势和缺点,并在此基础上提出...     

The Sonogashira Reaction in Ionic Liquids

Summary.  The Sonogashira reaction of iodobenzene with phenylacetylene in several room temperature ionic liquids was studied. A regeneration of the catalytical system immobilized in 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim]PF₆) has been also investigated. The reactivity of different iodoarenes with terminal alkynes in [bmim]PF₆ was studied as well. Corresponding author. E-mail: toma@fns.uniba.sk Received September 2, 2002; accepted September 9, 2002     

以离子液体为溶剂的原子转移自由基聚合

离子液体是一种有机盐,在接近室温下呈液状.离子液体是难挥发、极性高的溶剂,它能溶解很多种有机、无机和金属有机化合物.虽然有越来越多的人报道了有关离子液体在有机合成中的应用,但是在聚合过程中的应用却很少.然而在近几年,科学家证明了离子液体在聚合物的合成中的作用很大.在以离子液体为介质的自由基聚合反应中,kp/kt 会增大.尤其是在原子转移自由基聚合中,以离子液体作为溶剂有助于聚合物与残余催化剂的分离.本文主要阐述了原子转移自由基聚合反应的基本原理、特点以及离子液体在原子转移自由基聚合中的应用,并且还介绍了其他研究者的工作和原子转移自由基聚合的发展前景.     

Nanostructural Organization of Ionic Liquids: Theoretical and Experimental Evidences of the Presence of Well Defined Local Structures in Ionic Liquids

Summary. From an overview of the different theoretical and experimental methods it was possible to evidence the presence of aggregates in ionic liquids (ILs), and to specify their role in determining the unique physical-chemical properties of these media. An understanding of the structure of ILs, as pure compounds or in the presence of dissolved species, is fundamental if the reactivity and selectivity in ILs mediated reactions is to become predictive.     

Enhancing Task Specific Ionic Liquids’ Thermal Stability by Structural Modification

Summary. Thermal retro-Michael decomposition of task specific ionic liquids (TSILs) was efficiently suppressed by hydrogenation of the oxobutyl side chain yielding a hydroxy-functionalized TSIL.     

Enzymatic Reactions using Ionic Liquids for Green Sustainable Chemical Process; Stabilization and Activation of Lipases

The enzymatic reaction is highly respected from an environmentally-friendly point-of-view. Optimization of the reaction media and supporting materials of enzymes must be investigated in parallel with the effort to develop new enzymes. Lipases are frequently used for organic syntheses as synthetic tools even industry because of their acceptance of having a broad range of substrates, stability, and availability. We have investigated the possibility of ILs as both a solvent and activating or stabilization agent of enzymes, in particular, lipase as a model enzyme. ILs allowed recyclable use of a lipase and significant acceleration of transesterification, and also enhanced the stability and reaction activity of a lipase by immobilization through a lyophilization process. We discuss how we enhanced the enzyme capability using the IL engineering focusing on lipase-catalyzed reactions, i. e., realization of the recyclable use of an enzyme, how ILs mediated the enhanced reaction rate, and improved the stability of the enzyme.     

离子液体在电化学中的应用

离子液体作为绿色替代溶剂在电化学中的应用涉及电解、电镀、电催化、电池和电容技术等 ,在全球环境问题日益严峻的今天 ,电化学及其技术将显示重要作用。本文就离子液体这一新型的反应介质及其在电化学中的应用和研究进展加以阐述     

离子液体与生物大分子相互作用研究进展

离子液体作为一类新型绿色溶剂,因其独特的理化性质,被广泛应用于催化、有机合成、分离富集和电化学等领域。其中,离子液体在生物大分子的分离纯化、催化和降解方面显示出良好的应用前景,成为研究的热点领域之一。本文从离子液体与生物大分子的本质关系出发,对离子液体在DNA和蛋白质的分离纯化、酶的活性稳定性和天然纤维素溶解等过程中与生物大分子之间的相互作用进行了综述。     

含氟离子液体的研究进展

近年来人们对离子液体的兴趣不断增长。室温离子液体是一类熔点在室温附近的熔融盐,以其显著的特性在电化学、有机合成、催化、分离等领域被广泛应用。离子液体与氟化学紧密相关,离子液体中含有多种氟阴离子的烷基铵盐、咪唑盐等的合成、性质以及应用已经得到研究。离子液体的阴阳离子中氟原子数量和位置的不同,使离子液体具有不同的性质,如耐水性、耐温性、粘度、密度、表面张力、液体范围、导电性等。含氟的离子液体是离子液体的主要品种,它们凭借良好的可设计性和绿色环保的特点在当今化工工程的绿色化进程中显示出巨大的潜力和广阔的应用前景。     

高分子离子液体的研究进展

综述了高分子离子液体最新的研究进展。作为离子液体的载体材料主要有两大类 :一是无机高分子 ,离子液体中的阴离子或阳离子通过与无机高分子材料表面的基团键合形成含离子液体结构的高分子 ;二是有机高分子 ,在有机高分子上引入离子液体合成聚合物电解质 ,并介绍了其在催化、导电材料方面的应用前景     

Ferrocene as a Reference Redox Couple for Aprotic Ionic Liquids

The electrochemical behavior of ferrocene has been studied in a number of room temperature ionic liquids. Diffusion‐controlled, well‐defined anodic and cathodic peaks were found for the Fc/Fc⁺ (ferrocene/ferrocenium) oxidation/reduction on the gold electrode. Ohmic resistance R between working and auxiliary electrodes was deduced from impedance measurements. Cyclic voltammograms were corrected for the base line current as well as for the ohmic drop (IR). The formal potential 1/2(E_pa+E_pc) for ferrocene reduction/oxidation in aprotic ionic liquids tested is within a relatively narrow range and may be approximated by the value of 0.527±0.018 V (against the cryptate Ag/Ag⁺222 in acetonitrile reference). Ferrocene diffusion coefficients, calculated from the peak current dependence on the sweep rate, were of the order of 10^?7 cm² s^?1.     

离子液体溶解纤维素的研究

纤维素是一种可生物降解的天然高分子材料,由于纤维素含有大量的分子间和分子内氢键,导致纤维素难溶于水和一般的有机溶剂。现有的溶剂存在稳定性差、具有毒性、难以回收等缺点,对纤维素的加工、利用造成困难,因此,寻找新型绿色溶剂成为纤维素开发的热点和难点。离子液体是一种新型高效绿色溶剂,在一定条件下可以溶解纤维素、角蛋白等生物大分子,离子液体的出现为纤维素的溶解提供了一种环境友好、可生物降解的溶剂体系,具有广阔的应用前景。本文就不同种类离子液体溶解纤维素的溶解度以及影响溶解度的几种因素进行了综述,总结了离子液体与纤维素作用机理以及离子液体的回收方法,为纤维素的加工利用提供了理论依据和工业指导。     

离子液体中的酶催化反应

离子液体作为酶催化反应的介质正越来越多的受到关注,因为与传统有机溶剂和水相比,酶在离子液体中表现出了更好的活性、热稳定性、立体选择性、对映体选择性和可循环性。本文综述了近几年来脂肪酶、氧化还原酶、蛋白酶在离子液体中的催化反应。     

Polysaccharide Derivatives for Chromatographic Separation of Enantiomers

The first resolution of enantiomers was performed 150 years ago–mechanically. Today a powerful method for carrying out this task is HPLC on polysaccharide derivatives as chiral stationary phases. Most racemates, from an analytical to a preparative scale, now appear to be resolved by this technique. As an example, the chromatogram for the enantiomeric resolution of a fullerene derivative is shown on the right.     

新型N-甲基-N-烯丙基吗啡啉季铵盐类离子液体的合成

离子液体对某些无机和有机物溶解性能好、液态温度和电化学窗口范围宽、热稳定性高、易制备,因而近年来成为国内外研究的热点,目前的离子液体大多由烷基吡啶或双烷基咪唑季铵盐阳离子与氯铝酸根、氟硼酸根、六氟磷酸根以及其它大的阴离子构成,在季铵盐类离子液体中,     

One-pot Synthesis of Lewis Acidic Ionic Liquids for Friedel-Crafts Alkylation

Lewis acidic ionic liquids have been receiving extensive interest as green substitute for H2SO4, HF and AlCl3 catalysts in chemical processes1. In view of the principles of green chemistry2, ionic liquids themselves are highly expected to be obtained via …     

Lipase-catalyzed Irreversible Transesterification of Secondary Alcohols Using Isopropenyl Acetate

Summary. Asymmetric acetylation of a set of secondary alcohols with the innocuous acyl donor isopropenyl acetate catalyzed by a lipase from Pseudomonas cepacia immobilized on ceramic particles (PSL-C) in toluene as organic medium afforded the chiral alcohols and the corresponding acetates in high enantiomeric excess (up to 99%). An effective baseline separation of the enantiomers of both substrate and product was performed in one analysis without derivatization using gas chromatography on a new chiral stationary phase (CSP) Chirasil--Dex containing an undecamethylene spacer (C11-Chirasil-Dex).Received November 27, 2002; accepted (revised) January 9, 2003 Published online June 2, 2003