杂多酸离子液体催化的苯甲醇无溶剂选择性氧化

以十二烷基二甲基叔胺、1,3-丙烷磺内酯、磷钨酸/硅钨酸为起始原料经季铵化、酸化两步原子经济反应,合成了两种室温下为液相的多磺酸基官能化杂多酸离子液体S3ILs和S4ILs。目标离子液体的结构经红外光谱、核磁共振波谱得到确认。以S3ILs、S4ILs为均相催化剂,质量分数35%的H2O2为氧化剂,在无溶剂条件下实现了苯甲醇的选择性氧化,n(离子液体)∶n(醇)∶n(过氧化氢)=0.05∶30∶45,反应温度70℃,反应时间4 h时,S4ILs将苯甲醇氧化为对应的苯甲醛,产率81%~100%,S3ILs则将苯甲醇一步氧化为对应的苯甲酸,产率64%~94%。离子液体经旋蒸除水、乙醚洗涤、真空干燥即可循环使用,循环使用5次催化活性基本保持不变。     

离子液体促进正丁醛缩合反应研究

在正丁醛自缩合反应中加入离子液体1-丁基-3-甲基咪唑磷酸二丁酯,产物选择性得到提高,收率达到85.3%。合成了一种离子液体氢氧化胆碱(1),并用其替代氢氧化钠来催化该反应,结果表明,胆碱离子液体能够很好的催化正丁醛的自缩合反应,收率87.2%,而且离子液体可回收循环使用。产物结构由核磁共振氢谱表征。微波辅助下,两种离子液体促进的正丁醛自缩合反应的速率都得到了提高,缩短了反应时间。     

Study on Selective Dimerization of α-Methylstyrenes Promoted by Ionic Liquids

The catalytic systems composed of ionic liquids containing BF₄⁻ anion and HBF₄ showed high catalytic activity to produce 4-methyl-2,4-diphenyl-1-pentene (MDP-1) or 1,1,3-trimethyl-3-phenylindan (TPI) under different temperature conditions. Up to 90.8% selectivity to MDP-1 with a 98.7% conversion of α-methylstyrene was obtained at 60 °C in the presence of [HexMIm]BF₄–HBF₄, while exclusive TPI was yielded when the reaction temperature increased to 120 °C. Further studies showed that another ionic liquid, [BMIm]Cl · 2AlCl₃, could act as an excellent catalyst and solvent for the dimerization of α-methylstyrene to produce TPI. The dimerization of α-methylstyrene catalyzed by [HexMIm]BF₄–HBF₄ and [BMIm]Cl · 2AlCl₃ performed the same reaction mechanism and the proton was the active species.     

Pechmann Reaction in Non-Chloroaluminate Acidic Ionic Liquids under Solvent-Free Conditions

Four non-chloroaluminate acidic ionic liquids have been used as catalysts for Pechmann condensations of phenols under solvent-free conditions. SO₃H-functionalized trifluoromethanesulfonate imidazolium ionic liquid has proved to be the most active catalyst. Ionic liquid loads as low as 5 mol % can be used leading to high yields with activated phenols at an oil bath temperature of 80 °C. The acidities of the four ionic liquids have also been tested using the Hammett method in dichloromethane. The results are consistent with their catalytic activities as observed in the Pechmann reaction of resorcinol. This methodology offers significant improvements for the synthesis of coumarins with regard to yield of products, simplicity in operation, and green aspects by avoiding toxic catalysts and solvents.     

An Efficient Intramolecular Stetter Reaction in Room Temperature Ionic Liquids Promoted By Microwave Irradiation

This communication describes the first report of a microwave‐assisted intramolecular Stetter reaction using imidazolium‐type room temperature ionic liquids (RTILs) as solvents, with thiazolium salts and Et₃N as catalysts. The features such as good to excellent yields, shorter reaction time (5–20 min), and recyclable and reusable ionic liquid and catalyst make this method an environmentally benign and highly efficient procedure for the preparation of chromanone derivatives.     

Br(o)nsted酸性离子液体中苯甲酸酯、苄酯的无溶剂微波合成

该文以1-甲基咪唑、吡啶、苄基氯、硫酸、磷酸为原料,合成了4种Brnsted 酸性离子液体:1-甲基-3-苄基咪唑硫酸氢根盐(a),1-甲基-3-苄基咪唑磷酸二氢根盐(b),N-苄基吡啶硫酸氢根盐(c),N-苄基吡啶磷酸二氢根盐(d),以它们作为催化剂和反应介质,考察了苯甲酸与系列脂肪醇、苄醇与系列脂肪酸、苯甲酸在无溶剂和微波辐射反应条件下的Fischer酯化反应,结果表明,当苯甲酸或苄醇与离子液体的摩尔比为1∶ 0.5时,无需外加催化剂,反应即可在化学计量条件下进行,12～20 min完成反应,苯甲酸酯与苄酯的收率分别为77%～98%和78%～98.5%,气相色谱纯度≥95%.离子液体循环使用3次,催化活性仅下降1.8%～3.4%.     

普通离子液体和功能化离子液体的合成研究进展

离子液体是在室温下为液体、具有离子特性的新型绿色溶剂,作为一类环境友好型的反应介质,在诸多领域有其独特的性质.综述了普通离子液体和功能化离子液体的合成研究进展,并对其前景进行了展望.     

离子液体的应用

离子液体是室温下呈液态的离子化合物,是一类新型的"软"功能材料或介质,具有优良的可设计性,它作为一种绿色溶剂,具有很多独特的物理化学性能。介绍了离子液体在纤维素科学、有机反应、分离过程、电化学中的应用。     

离子液体的合成

离子液体作为一类新型的环境友好的。绿色溶剂”,具有很多独特的性质,在很多领域有着诱人的应用前景。本文主要介绍了以N,N’-二烷基咪唑阳离子,N-烷基吡啶阳离子与含氟阴离子,氯酸铝阴离子等形成的室温离子液体的合成方法。     

Ionic Liquids in Biomass Processing

The ionic liquids have emerged as new solvents and catalysts for processing biomass to value added chemicals and fuels. This review will present the recent developments in applications of ionic liquids in lignocellulosic biomass pretreatments, depolymerization, biodiesel synthesis, dehydration of carbohydrates to renewable feedstock chemicals as well as further transformations of biomass derived feedstocks such as furfural, 5‐hydroxymethylfurfural and levulinic acid to value added chemicals. In addition, the recycling of ionic liquids used in biomass processing is also discussed in the review.     

手性功能化离子液体的合成进展

手性离子液体作为功能化离子液体的一种,综合了离子液体与手性物质两方面的特性。不仅具有手性特征,而且几乎无蒸气压,无可燃性,具有很高的热力学和化学稳定性,电导率高,可以循环使用,对无机和有机物有良好的溶解性、稳定性等。手性离子液体可以作为手性溶剂,催化剂载体或手性诱导剂,应用于手性合成、手性分离和手性催化等领域。本文综述了近些年来手性离子液体合成的最新进展,结构上按阴、阳离子分类,同一离子类型中按物质种类分类。同时介绍了一些新的合成技术。最后对手性离子液体可能的发展趋势和以后的研究方向进行了展望。     

Ionic Liquids in Oxygen Compression

Ionic liquids are still a relatively new and very promising class of substances which have received increased research attention in recent years. Due to their unique physical and chemical properties these compounds are ideal for use in industrial applications and also offer a variety of very interesting possibilities in process technology, with a high potential of increasing performance and reducing investment and operating costs [1]. Ionic liquids are remarkable for their high chemical inertness and good lubricity. Therefore, one very promising application is the lubricated compression of oxygen as an alternative to the dry compression technique that has to be used because of the extremely high reactivity of pure oxygen with organic lubricating media. A screening of the relevant parameters including thermal stability, flammability, chemical inertness to pure oxygen, corrosiveness, tribological behavior and oxygen solubility was performed. Based on the results obtained, the most suitable ionic liquid was identified and used in a screw compressor setup that achieves a final pressure of 30 bar with a delivery volume of up to 200 Nm³/h.     

Microwave Promoted Alkylation of Halonitrobenzene with Malonates in Solvent-free Medium

Abstract The alkylations on different substituted halonitro benzenes have been demonstrated with various malonates under the influence of microwaves irradiation. The reactions were catalyzed by potassium carbonate and benzyltriethylammoniumchloride. The salient features of this methodology are mild reaction conditions, high regio-selectivity, rapid conversions, solvent-free medium and easy isolation of products Graphical abstract Microwave Promoted Alkylation of Halonitrobenzene with Malonates in Solvent-free Medium Venkat Narsaiah Akkirala      

六氟锑酸盐离子液体的研究进展

六氟锑酸盐离子液体具有常规离子液体的特性,如低蒸汽压、不挥发、物质溶解性好等,不仅可以作为溶剂,还可以通过调配阴阳离子比例或离子交换得到路易斯酸催化剂,在多种类型反应中得到应用。主要对近年来六氟锑酸盐离子液体的合成、结构、性质及其在反应中的应用进行综述。     

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。     

离子液体及其在电化学中的应用

离子液体即在室温或接近室温下呈液态的完全由离子构成的物质,作为环境友好和“可设计性”溶剂正在引起越来越多的重视。它具有熔点低、蒸汽压小、酸性可调及良好的溶解度、粘度和密度等特点。综述了离子液体的组成、分类、性质、制备和纯化,就离子液体在电池技术、电合成、电沉积、电容器等电化学方面的应用和研究进展加以阐述,并对该领域的研究前景作了展望。     

壳聚糖在离子液体中的改性

壳聚糖是储量仅次于纤维素的重要的生物质资源,其清洁转化和综合利用是绿色化学的一项基础性、前瞻性课题。离子液体作为一类新型绿色介质,在生物质资源利用研究中受到国际学术界和工业界的高度关注。以离子液体替代传统溶剂有望为壳聚糖的转化利用带来巨大的经济和社会效应。综述了壳聚糖在离子液体中的降解、酯化、接枝以及复合材料制备等改性研究。     

金属在离子液体中的电沉积研究综述

离子液体是在室温或接近室温条件下由离子组成的电解质。在离子液体中可以沉积出元素周期表中的大多金属、半导体金属及其化合物。简要介绍了离子液体的发展历史、种类和特点,并介绍了金属在不同种类离子液体中的电沉积,论述了在离子液体中金属电沉积应用的机遇与挑战。