新型液／液两相催化体系——π配体离子液体的研究进展

离子液体与配体催化剂的结合有助于解决反应效率、产物分离和催化剂循环等一系列均相催化体系不易解决的难题。近年来,随着研究的不断深入,相继出现了如下的研究思路：利用π配体催化剂与离子液体形成络合物;使用离子型π配体改善催化剂在离子液体中的溶解性;合成功能化阳离子或功能化阴离子的π配体离子液体。本文结合这几类离子液体化学键联Ⅱ配体的研究进展,从离子液体功能化设计的角度探讨了π配体离子液体的合成思路,为设计具有更好催化性能的功能化离子液体体系打下了一定的基础。     

离子液体参与的两相催化进展

综述近年来离子液体催化体系在有机反应研究领域的新进展,重点介绍离子液体在有机反应中的优势,反应条件温和、催化剂活性高、选择性好,催化剂易与产物分离,催化剂易多次重复利用。     

硅材料固载离子液体挂载金属催化剂应用研究进展

离子液体具有独特的性质,将具有高表面积的硅材料用离子液体进行改性,再挂载金属化合物,可制得集离子液体中均相催化和固体非均相催化体系于一身的新型催化剂,用于多种有机反应.这些催化剂具有高效、高选择性、离子液体用量少、产品易分离和催化剂易回收等优点,因有望用于化工过程的固定床反应器而受到关注.本文综述了2005年以来硅材料固载离子液体挂载金属催化剂的应用研究成果.     

离子液体载催化剂在医药中间体环戊烷并吡啶合成的应用

以氯代正丁烷、N-甲基咪唑和氯化铜为原料，制备了离子液体载催化剂BMImCuCl3，通过红外光谱和核磁共振波谱对其结构进行了表征，研究了其在催化环戊酮与丙炔胺环合成环戊烷并吡啶反应中的应用。结果表明，较为合适的催化体系为BMImBF4／BMImCuCl3，催化剂BMImCuCl3的用量为10％，反应物摩尔比为1：1．5，反应温度为60℃，反应时间为3h，收率达67．3％。该离子液体催化体系循环使用3次，催化活性没有明显降低。与传统合成方法相比，在离子液体中的合成方法具有反应时间短、选择性和收率高，离子液体载催化剂可以循环使用等优点。     

离子液体在可逆加成-断裂链转移聚合中的应用

离子液体具有优良的物理化学性能,受到研究者的广泛关注.近年来,有关离子液体在可逆加成-断裂链转移(RAFT)聚合反应中的应用有大量的研究报道.作为溶剂,离子液体能溶解一些较难溶解的聚合物,如纤维素和壳聚糖等,可以为聚合反应提供较好的反应环境;作为单体,通过RAFT聚合可制备出聚合离子液体均聚物或带有聚合离子液体链段的嵌段聚合物,可以应用于燃料电池电解质膜、太阳能电池、催化、分离及吸附剂等领域;离子液体还可以作为表面活性剂,应用于RAFT的乳液聚合或细乳液聚合,有效地稳定和控制聚合物颗粒大小.从溶剂、单体和表面活性剂方面出发,简单总结了离子液体在RAFT聚合反应中的应用.     

离子液体在高分子合成中的应用

离子液体作为一种"绿色溶剂",具有很多独特的物理化学性能,可以应用于自由基聚合、阳离子聚合、配位聚合、电化学聚合等反应体系。本文阐述了离子液体的特点及合成方法,介绍了离子液体在高分子合成中的应用。     

离子液体在生物燃料制备中的应用研究进展

近年来,离子液体作为新型功能材料,在生物燃料制备中的应用逐渐增多。离子液体具有蒸汽压小、熔点低和液态温度范围宽等特点;在生物燃料制备中,具有不腐蚀设备、不污染环境、能够重复使用的优点。介绍了离子液体中纤维素的预处理、溶解和水解等;同时阐述了离子液体作为催化剂、溶剂及催化剂载体在生物柴油合成方面的应用研究进展,最后展望了离子液体在可再生生物燃料制备中的发展方向。     

酸性离子液体催化合成二元羧酸酯研究进展

二元羧酸酯是重要的工业原料和有机化工产品,具有广阔的应用前景,因此开发一种催化活性高、重复使用性能好、后处理简单的催化剂成为近年来的一项重要任务。离子液体作为新型绿色催化剂,在二元羧酸酯研究中表现出良好的发展趋势。综述了近年来离子液体在催化合成二元羧酸酯反应中的研究进展,探索了二元羧酸酯的合成机理,指出了目前离子液体催化剂发展需要解决的瓶颈问题及今后的发展方向。     

北京石油化工学院 恩泽生物质精细化工北京市重点实验室部分科研成果

<正>离子液体催化合成醋酸正丙酯技术醋酸正丙酯对多种合成树脂具有优良的溶解能力,常用于有机合成过程和用作涂料、印刷油墨等的溶剂,也是工业上常用的脱水剂,醋酸正丙酯酯化反应通常采用浓硫酸作为催化剂,但存在设备腐     

磁性离子液体的制备与应用研究进展

磁性离子液体是一种新型的功能化离子液体材料,具有优良的热稳定性、优异的电化学性能、良好的溶解性能以及可回收性等特性,使其在萃取分离、反应催化和复合材料等领域具有较好的应用前景。对目前合成的磁性离子液体做了概述并根据构效关系对主要的磁性离子液体进行了分类。综述了磁性离子液体的主要制备方法,主要有一步合成法、二步合成法和辅助合成法。介绍了磁性离子液体在萃取分离、反应催化及碳纳米管复合材料领域应用研究进展。最后根据磁性离子液体在合成和应用中的不足做了展望。     

Preparation of AgX (X = Cl, I) nanoparticles using ionic liquids

Nanoparticles of silver halides have been prepared by mixing silver halide powder with a single liquid phase consisting of an ionic liquid, isooctane, n-decanol and water. Much higher nanoparticle concentrations may be formed with ionic liquids using this new simple method than are found with conventionally applied surfactants. This method also emphasizes the applicability of ionic liquids as versatile components in microemulsions and as solvents for the synthesis of nanomaterials. The effect on the nanoparticles of changing the composition of the liquid mixtures and the nature of the ionic liquid is analysed. High nanoparticle concentrations were only found with chloride based ionic liquids, indicating the importance of the ionic liquid anion in the mechanism of the reaction.     

Graphene oxide : a novel acid catalyst for the synthesis of 2,5-dimethyl-N-phenyl pyrrole by the Paal-Knorr condensation北大核心CSCD

Graphene oxide (GO) was used as an efficient and recyclable catalyst for the synthesis of N-substituted pyrrole using a Paal-Knorr condensation reaction between 2,5-hexanedione and aniline. The effects of reaction time, reaction temperature, solvent, catalyst loading and molar ratio of aniline to 2,5-hexanedione on the yield of 2,5-dimethyl-N-phenyl pyrrole were investigated. In situ NMR was used to follow the Paal-Knorr reaction at the molecular level. Results revealed that the oxygen-containing groups of GO, such as sulfonic acid and carboxyl groups, played a key role in this catalytic reaction. Polar protic solvents were favorable for the reaction. The catalytic activity increased with temperature without any side reaction. The GO could be easily recovered and showed remarkable reusability and excellent catalytic performance allowing it to be reused 5 times.     

"枣糕状"结构杂多酸离子液体负载磁性复合材料的制备及超声脱硫的催化性能

石油中的含硫化合物不仅影响油品质量,其燃烧生成的硫氧化物(SOx)还会对生态环境和人类健康构成极大威胁.此外,燃油中的硫化物燃烧使得燃油尾气处理设备中催化剂中毒,从而排放一些其他有害的汽车尾气,如氮氧化物(NOx)、碳氢化合物和一氧化碳(CO)等.为了降低燃油中的硫含量,世界各国政府都颁布了严格的标准,如美国环保署在2006年将柴油中的硫含量降低到15 mg/kg;2007年欧盟和日本将柴油中的硫含量上限设定为10 mg/kg.自2017年起,我国政府发布了国V标准,将柴油中的硫含量限制在10 mg/kg以下.随着各项政策的出台,如何通过高效深度脱硫技术降低石油中的硫含量已成为石油化工领域的研究热点.同时,超深脱硫在解决工业废物再利用中也发挥着重要作用.目前常用的深度脱硫的方法主要有加氢脱硫(HDS)和非加氢脱硫(NHDS).由于传统的HDS方法存在去除噻吩类物质困难、成本高、条件苛刻、耗时耗能等缺点,NHDS以其低能耗、环保等优点逐渐受到人们的青睐.NHDS技术包括氧化脱硫、吸附脱硫、萃取脱硫和生物脱硫等.其中,氧化脱硫可以通过氧化剂将有机硫化物转化为砜或亚砜,提高有机硫化物在极性溶剂中的溶解度,通过萃取和蒸馏等方法将有机硫化物从石油中分离出来,达到深度脱硫的目的.与机械搅拌、生物或光催化氧化脱硫等传统脱硫方法相比,超声辅助氧化脱硫法是反应时间最短、效率最高的方法之一.近年来,离子液体因良好的热稳定性和化学稳定性而受到越来越多的关注,并被广泛应用于催化氧化脱硫.在杂多酸中引入离子液体可以形成具有氧化活性中心的杂多酸离子液体,有望表现出优异的催化活性.Xun等采用溶胶-凝胶法制备了杂多酸离子液体催化剂(SiW12O40-IL),该催化剂在脱硫方面具有优异的催化活性,当温度为60℃,n(O)/n(S)为4时,其脱硫率达到99.9％.然而,作为均相催化剂,杂多酸离子液体也存在回收率低、可重复利用性差等缺点,因此选择合适的固载化方法,实现杂多酸离子液体催化剂的异相化十分关键.常用的载体有SiO2、Al2O3、Fe3O4等,其中磁性复合材料可以实现催化剂和油样在磁场作用下的快速分离,已成为目前最为流行的载体之一.将磁性复合材料通过改性结合到催化剂上,有望得到具有较高的脱硫催化活性和优异分离效果的催化剂.为此,本研究设计并成功合成了一种具有"枣糕状"结构的、杂多酸离子液体[BMIM]3 PW12O40负载的三乙烯四胺(TETA)功能化的Fe3O4复合材料([BMIM]3 PW12O40/Fe3O4@TETA).以正辛烷为模拟油样,二苯并噻吩为硫源,过氧化氢为氧化剂,[BMIM]3PW12O40/Fe3O4@TETA为催化剂,通过超声协助考察了催化剂的催化氧化脱硫.采用响应面法(RSM)研究了超声时间、H2O2用量、反应温度对催化剂脱硫的影响;并考察了催化剂的稳定性和再生性能.对[BMIM]3PW12O40/Fe3O4@TETA的脱硫机理进行了初步探讨,结果表明,采用0.025 g[BMIM]3PW12O40/Fe3O4@TETA对50 mL浓度为500 mg/g的二苯并噻吩的模拟油样进行脱硫实验时,最佳脱硫条件为:反应温度325 K,超声时间15 min,n(O):n(S)=8:1,脱硫率可达96.5％.该催化剂重复使用五次后,脱硫率仍保持在93.7％,表明[BMIM]3PW12O40/Fe3O4@TETA具有良好的催化脱硫性能,可以重复使用.初步的脱硫机理研究表明,[BMIM]3PW12O40/Fe3O4@TETA的催化活性中心可能为其含有的杂多酸阴离子;Fe3O4@TETA起到载体的作用,而离子液体起到协同增强作用.     

Synthesis and electrochemical performances of LiNiCuZn oxides as anode and cathode catalyst for low temperature solid oxide fuel cell

Low temperature solid oxide fuel cell (LTSOFC, 300-600 degrees C) is developed with advantages compared to conventional SOFC (800-1000 degrees C). The electrodes with good catalytic activity, high electronic and ionic conductivity are required to achieve high power output. In this work, a LiNiCuZn oxides as anode and cathode catalyst is prepared by slurry method. The structure and morphology of the prepared LiNiCuZn oxides are characterized by X-ray diffraction and field emission scanning electron microscopy. The LiNiCuZn oxides prepared by slurry method are nano Li0.28Ni0.72O, ZnO and CuO compound. The nano-crystallites are congregated to form ball-shape particles with diameter of 800-1000 nm. The LiNiCuZn oxides electrodes exhibits high ion conductivity and low polarization resistance to hydrogen oxidation reaction and oxygen reduction reaction at low temperature. The LTSOFC using the LiNiCuZn oxides electrodes demonstrates good cell performance of 1000 mW cm(-2) when it operates at 470 degrees C. It is considered that nano-composite would be an effective way to develop catalyst for LTSOFC.     

Preparation and application of granular ZnO/Al2O3 catalyst for the removal of hazardous trichloroethylene

Trichloroethylene (TCE) is a volatile and nerve-toxic liquid, which is widely used in many industries as an organic solvent. Without proper treatment, it will be volatilized into the atmosphere easily and hazardous to the human health and the environment. This study tries to prepare granular ZnO/Al(2)O(3) catalyst by a modified oil-drop sol-gel process incorporated the incipient wetness impregnation method and estimates its performance on the catalytic decomposition of TCE. The effects of different preparation and operation conditions are also investigated. Experimental results show that the granular ZnO/Al(2)O(3) catalyst has good catalytic performance on TCE decomposition and the conversion of TCE is 98%. ZnO/Al(2)O(3)(N) catalyst has better performance than ZnO/Al(2)O(3)(O) at high temperature. Five percent of active metal concentration and 550 degrees C calcination temperature are the better and economic preparation conditions, and the optimum operation temperature and space velocity are 450 degrees C and 18,000 h(-1), respectively. The conversions of TCE are similar and all higher than 90% as the oxygen concentration in feed gas is higher than 5%. By Fourier transform infrared spectrography (FT-IR) analyses, the major reaction products in the catalytic decomposition of TCE are HCl and CO(2). The Brunauer-Emmett-Teller (BET) surface areas of catalysts are significantly decreased as the calcination temperature is higher than 550 degrees C due to the sintering of catalyst materials, as well as the reaction temperature is higher than 150 degrees C due to the accumulations of reaction residues on the surfaces of catalysts. These results are also demonstrated by the results of scanning electron micrography (SEM) and energy disperse spectrography (EDS).     

Preparation of Inorganic Materials Using Ionic Liquids

Conventional synthesis of inorganic materials relies heavily on water and organic solvents. Alternatively, the synthesis of inorganic materials using, or in the presence of, ionic liquids represents a burgeoning direction in materials chemistry. Use of ionic liquids in solvent extraction and organic catalysis has been extensively studied, but their use in inorganic synthesis has just begun. Ionic liquids are a family of non‐conventional molten salts that can act as templates and precursors to inorganic materials, as well as solvents. They offer many advantages, such as negligible vapor pressures, wide liquidus ranges, good thermal stability, tunable solubility for both organic and inorganic molecules, and much synthetic flexibility. In this Review, the use of ionic liquids in the preparation of several categories of inorganic and hybrid materials (i.e., metal structures, non‐metal elements, silicas, organosilicas, metal oxides, metal chalcogenides, metal salts, open‐framework structures, ionic liquid‐functionalized materials, and supported ionic liquids) is summarized. The status quo of the research field is assessed, and some future perspectives are furnished.     

Examination of ionic liquids and their interaction with molecules, when used as stationary phases in gas chromatography.

Stable room-temperature ionic liquids (RTILs) have been used as novel reaction solvents. They can solubilize complex polar molecules such as cyclodextrins and glycopeptides. Their wetting ability and viscosity allow them to be coated onto fused silica capillaries. Thus, 1-butyl-3-methylimidazolium hexafluorophosphate and the analogous chloride salt can be used as stationary phases for gas chromatography (GC). Using inverse GC, one can examine the nature of these ionic liquids via their interactions with a variety of compounds. The Rohrschneider-McReynolds constants were determined for both ionic liquids and a popular commercial polysiloxane stationary phase. Ionic liquid stationary phases seem to have a dual nature. They appear to act as a low-polarity stationary phase to nonpolar compounds. However, molecules with strong proton donor groups, in particular, are tenaciously retained. The nature of the anion can have a significant effect on both the solubilizing ability and the selectivity of ionic liquid stationary phases. It appears that the unusual properties of ionic liquids could make them beneficial in many areas of separation science.     

Ion-exchange membranes made of semi-interpenetrating polymer networks,used for pervaporation-assisted esterification and ion transport

Ionic membranes were prepared by blending poly(vinyl alcohol) (PVA) with an ionic polymer. Semi-interpenetrating polymer networks (sIPN) in which the crosslinked PVA chains trap the ionic polymer were obtained by using a heat treatment at 180 °C or dibromoethane vapor at 140 °C, respectively, for poly (styrene sulfonic acid) (PSSH), poly (sodium styrene sulfonate) (PSSNa), poly (acrylic acid) (PAA) or poly (dimethyl dimethylene piperidinum chloride) (PDMeDMPCl) as the ionic polymer. The stability of the sIPN membranes in some liquid media was studied to select the appropriate membranes for the envisaged applications. The thermally crosslinked PVA/PSSH membranes showed an effective catalytic effect on the esterification reaction between n-propanol and propanoic acid. An active composite membrane made of a layer of PVA/PSSH deposited on a dense PVA layer of an industrial dehydration membrane exhibited both high catalytic activity and high selectivity to water in the pervaporation-assisted esterification. The values of the counter-ion transport number indicated that some crosslinked ionic membranes have good ion permselectivity.     

Synthesis and characterization of poly(ionic liquid)-grafted silica hybrid materials through surface radical chain-transfer polymerization and aqueous anion-exchange

Poly(ionic liquid)-grafted silica materials were firstly synthesized by polymerization of 1-vinyl-3-butylimidazolium bromide as a new ionic liquid monomer on mercaptopropylated silica by surface radical chain-transfer polymerization. The bromide counterion was exchanged with three other inorganic anions including tetrafluoroborate, hexafluorophosphate, and trifuoromethanesulfonate through simple aqueous anion-exchange reaction. The obtained poly(ionic liquid)-grafted silica materials were characterized by elemental analysis, infrared spectra, thermogravimetric analysis, and X-ray fluorescence. The wettabilities of the materials with different counterions were verified by static water contact angle measurement. This kind of new materials may have some potential in applied fields such as used as a catalyst, an extractant, a chromatographic stationary phase, etc.