离子液体载催化剂和载试剂在有机合成中的应用

综述了离子液体载催化剂和载试剂在有机合成中的应用进展. 离子液体载催化剂是针对离子液体中催化剂难以回收利用的问题提出来的, 它不仅可以实现均相催化, 而且反应产物容易分离, 催化剂可以循环使用. 离子液体载有机试剂合成, 又称为离子液体相有机合成, 具有固相反应产物纯度高和液相反应反应快的优点. 在离子液体载无机试剂的反应中, 反应物毒性降低, 反应条件温和, 产物选择性好.     

固定化离子液体在有机合成中的应用

固定化离子液体是将离子液体通过物理吸附或化学键合等方法与固载材料结合而成,不仅保持了离子液体稳定性好、挥发性低、结构可优化等特点,还提高了离子液体的催化活性和重复利用性。固定化离子液体广泛应用于缩合、偶联及不对称合成等反应中。本文介绍了固定化离子液体的制备、固载材料的分类、结合方式及固定化离子液体在有机合成中的应用进展。     

利用离子液体负载反应底物的有机合成

综述了固相、液相组合化学中以可溶性离子液体为载体的有机合成新概念及最新研究进展,并主要介绍了离子液体作为载体负载反应底物在有机合成中的一些应用,如有关的重要有机反应、组合化学、小分子库合成等。该方法具有上载率高、适用反应范围宽、分离纯化简便、结构检测容易和可回收重复使用等诸多优越性,这对于传统的固相、液相合成方法是一个重大的进步。     

基于功能离子液体促进的有机反应研究进展

离子液体作为绿色溶剂和催化剂,具有低挥发性,优良的热稳定性、溶解性以及可回收等优点,近年来广泛应用于有机合成领域中,在提高反应速率,反应选择性等方面发挥了巨大作用.综述了离子液体作为催化剂或溶剂在传统有机合成反应中的最新研究成果,包括Baylis-Hillman反应、Michael加成反应、氧化还原反应、Knoevenagel缩合反应、Aldol缩合反应、Diels-Alder反应、Heck偶联反应、Suzuki反应、不对称反应、Biginelli反应、Mannich反应、Hantzsch多组分反应.分析离子液体结构对反应催化性能的影响,探讨其反应机理,为开发新型结构可调性功能离子液体打下基础.     

离子液体在有机合成中的应用研究进展

离子液体由于具有特殊的性质, 包括低挥发性、大极性、良好的热稳定性、通过调整阴阳离子选择不同的溶解性等特点, 已经作为反应介质或催化剂广泛应用于有机合成领域, 引起了人们足够的兴趣. 与传统有机溶剂反应相比, 离子液体相反应得到的产物收率高, 选择性好, 加快部分类型反应的速率, 后处理简单以及离子液体催化剂体系简单, 回收后, 可多次重复使用. 综述了离子液体作为反应介质或催化剂在有机合成传统反应类型中的最新研究成果, 主要包括: 偶联反应、Michael加成、Baylis-Hillman反应、Diels-Alder反应、Aldol缩合、Knoevenagel缩合、环化反应、烷基化及酰基化反应和氧化还原反应.     

手性胍盐离子液体的合成

离子液体作溶剂、催化剂进行有机合成反应是近几年来各国化学家关注的热点之一[1].究其原因主要是离子液体具有低熔点、不挥发、不易燃易爆等特点,使其能代替传统有机合成与工业催化工程中的易挥发性溶剂(VOCs).再就是离子液体作为一种离子溶剂,可能存在1018种二元离子液体,而现在实际应用中的分子溶剂大概600种,离子液体的多样性使得在实际应用中可以通过调节离子液体的结构来调节离子液体的性质,从而为反应提供合适的溶剂环境,从而提高反应的产率、选择性以及立体选择性等[2].手性离子液体的合成和离子液体中的不对称催化一直都是离子液体研究的一个重要方面.Wasserscheid等[3,4]最近报道了从"手性池"(Chiral pool)衍生的新手性离子液体的合成和特性.最近我们报道一类简单的胍盐室温离子液体的合成及性质[5,6],新型胍盐离子液体由于其独特的性质得到了大家的关注[7-8].而手性胍盐离子液体还未见文献报道,因此我们从简单易得的手性胺出发合成了一系列的手性胍盐离子液体(Scheme 1),以新的手性胍盐离子液体作为不对称性催化反应新体系的工作正在进行.     

离子液体在羰基化反应中的应用

离子液体由于具有良好的溶解能力、配位能力、热及化学稳定性、结构及性质可调、环境友好等特点,被认为是传统非环保型、有毒、污染严重的溶剂和催化剂潜在的替代品,已被广泛应用于有机合成及催化领域。本文综述了近年来离子液体在羰基化反应中的应用及催化反应机理研究进展,包括烯烃、醇类化合物、芳烃、胺/胺醇、卤代芳烃及甲醛的羰基化反应,羰基源主要包括CO、CO₂和碳酸二甲酯,涉及到了酸性离子液体、碱性离子液体、金属类离子液体、负载型离子液体等多种类型的功能化及非功能化离子液体。在上述反应中离子液体不仅可以提高反应活性和选择性,而且简化了催化剂分离过程,在部分反应中实现了回收和循环使用。并对羰基化反应的发展及应用前景进行了展望。     

低共熔溶剂催化有机合成反应的研究进展

低共熔溶剂(DESs)是一种新型的离子液体(ILs)类似物,与传统有机溶剂、离子液体相比,DESs具有低毒、廉价、易于合成、生物可降解性等特点,因此在众多领域广受关注。近年来DESs在有机合成领域备受关注,被广泛用作合成反应的溶剂、催化剂、反应物等,在有机反应方面存在很大发展空间,本文综述了DESs在有机合成反应中的应用,重点讨论其在氧化还原反应、取代反应、缩合反应、环化反应等方面的研究进展,为其开发应用提供新思路。     

离子液体与微波协同促进有机合成反应

介绍了离子液体作溶剂、助溶剂、催化剂和反应试剂与微波协同促进有机合成的研究进展。离子液体与微波协同促进有机合成反应,缩短了反应时间,提高了反应的选择性和产率,对环境更加友好。     

聚乙二醇功能化离子液体的制备及其在有机反应中的应用

聚乙二醇功能化离子液体作为一个新的研究方向受到了化学研究者关注,该类离子液体已经成功地应用于许多有机合成反应中,可以明显改善催化剂性能,并可在一定程度上解决传统催化剂使用中遇到的难分离、难回收再利用的问题。本文介绍了聚乙二醇功能化离子液体的发展历程、制备方法和其作为反应介质、溶剂或催化剂在有机合成反应中应用的最新研究成果,主要包括加成反应、缩合反应、还原反应、酯化反应、硝化反应、氧化反应、水解反应、Heck 反应以及Suzuki-Miyaura反应等。     

Efficient combination of task-specific ionic liquid and microwave dielectric heating applied to one-pot three component synthesis of a small library of 4-thiazolidinones

The first report of the use of task-specific ionic liquid as synthetic equivalent of ionic liquid-phase matrice for the preparation of a small library of 4-thiazolidinones is reported in this paper. The starting (ethyleneglycol)ionic liquid-phase is functionalized in good yields with 4-(formylphenoxy)butyric acid by using usual esterification reaction conditions (DCC/DMAP as catalyst). The synthesis of the ionic liquid-phase bound 4-thiazolidinones was performed by a one-pot three-component condensation under microwave dielectric heating. The final cleavage under microwave/catalysis strategy provides the expected 4-thiazolidinones in high purity after flash-chromatography purification. According to the ionic liquid-phase organic synthesis (IoLiPOS) methodology, it was found that optimized reaction conditions were performed by standard analytical methods (NMR, TLC). The ¹H, ¹³C NMR spectrum of some representative 4-thiazolidinones and ionic liquid-phase bound benzaldehyde are also reported.     

Microwave-assisted liquid-phase synthesis of methyl 6-amino-5-cyano-4-aryl-2-methyl-4H-pyran-3-carboxylate using functional ionic liquid as soluble support

A microwave-assisted liquid-phase synthesis of methyl 6-amino-5-cyano-4-aryl-2-methyl-4H-pyran-3-carboxylate was developed using functional ionic liquid as soluble support. IL-bound acetoacetate was treated with arylidenemalononitriles to give supported 4H-pyran derivatives. After cleavage, the target compounds were obtained in good yields and high purities without chromatographic purification.     

微波辅助离子液体法在液相合成中的应用

作为一种新型的绿色化学合成方法,微波辅助离子液体法融合了离子液体与微波加热法的优点,具有合成快速、操作简便、产率高,绿色环保等特点,在液相合成方面体现出明显的优势。本文综述了离子液体作为微波吸收剂在液相有机合成、无机纳米材料合成方面的研究进展,对比分析了微波辅助离子液体法同多种传统方法的应用效果,阐明了该方法的优势,并展望该领域今后的发展方向。     

Characterization of the ability of CO2 to act as an antisolvent for ionic liquid/organic mixtures

This paper discusses the ability of CO2 to induce liquid/liquid-phase separation in mixtures of ionic liquids and organics. New data for the solubility of CO2 in the ionic liquid/organic mixtures and the volume expansion of the mixtures with added CO2 are used to analyze the results. Acetonitrile, 2-butanone, and 2,2,2-trifluoroethanol are chosen to distinguish dipolar and hydrogen-bonding interactions. Likewise, 1-n-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-n-hexyl-2,3-dimethylimidazolium bis(trifluoromethylsulfonyl)imide, 1-n-hexyl-3-methylimidazolium triflate, and ethyl-dimethyl-propylammonium bis (trifluoromethylsulfonyl)imide were studied to vary hydrogen-bond-donating and -accepting abilities of the ionic liquids. Primarily, the ability of CO2 to act as an antisolvent depends on the solubility of the CO2 in the ionic liquid/organic mixture. Strong hydrogen bonding between the ionic liquid and the organic makes it more difficult for CO2 to induce a liquid/liquid-phase separation.     

负载离子液体纳米钯催化芳卤羰化反应

研究了高分散性的负载离子液体纳米钯催化剂的制备及其催化芳卤羰化反应的性能. 用XRD、HRTEM和XPS等方法对催化剂进行了表征, 结果表明, 钯组分处于高分散零价态, 其平均粒径小于5 nm, 且催化剂表面存在一厚度适中的离子液体液膜, 有利于提高催化剂的稳定性; 该催化剂对PhI、PhBr、PhCl的羰化反应的催化活性优于离子液体两相催化体系, 在优化的反应条件下, 碘苯的转化率可达99.3％, 生成苯甲酸乙酯的转化频率(TOF)可高达4926 h−1, 反应产物中苯甲酸乙酯的选择性大于99％.     

Versatile supramolecular gelators that can harden water, organic solvents and ionic liquids

We developed novel supramolecular gelators with simple molecular structures that could harden a broad range of solvents: aqueous solutions of a wide pH range, organic solvents, edible oil, biodiesel, and ionic liquids at gelation concentrations of 0.1-2 wt %. The supramolecular gelators were composed of a long hydrophobic tail, amino acids and gluconic acid, which were prepared by liquid-phase synthesis. Among seven types of the gelators synthesized, the gelators containing L-Val, L-Leu, and L-Ile exhibited high gelation ability to various solvents. These gelators were soluble in aqueous and organic solvents, and also in ionic liquids at high temperature. The gelation of these solvents was thermally reversible. The microscopic observations (TEM, SEM, and CLSM) and small-angle X-ray scattering (SAXS) measurements suggested that the gelator molecules self-assembled to form entangled nanofibers in a large variety of solvents, resulting in the gelation of these solvents. Molecular mechanics and density functional theory (DFT) calculations indicated the possible molecular packing of the gelator in the nanofibers. Interestingly, the gelation of an ionic liquid by our gelator did not affect the ionic conductivity of the ionic liquid, which would provide an advantage to electrochemical applications.     

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.     

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.     

Synthesis of a series of novel dihydro-[1,2,4]triazolo [1,5-a]pyrimidine scaffolds: Dual solvent-catalyst activity of a low viscous and acid-functionalized ionic liquid

Abstract

The viscosity of neat ionic liquids is very important for their application in organic synthesis as a solvent because most of the neat ionic liquids are very viscous, which would result in the less efficient mass transfer of reactants. In the present study, a series of novel dihydro-[1,2,4]triazolo[1,5-a]pyrimidines were prepared using a low viscous and acid-functionalized ionic liquid. Our results showed that new ionic liquid can act as a green solvent and acid catalyst due to low viscosity and acid functionality. The products were simply extracted and the ionic liquid was retrieved several times without reducing its catalytic efficiency. The current application of TMDPS in the one-pot multicomponent reactions as dual solvent-catalyst highlights the importance of low viscous acid-functionalized ionic liquids in organic synthesis, and we hope that further research will be conducted in the future to finding other applications of TMDPS with promising results.