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1.
Gilles Moos Meike Emondts Alexis Bordet Walter Leitner 《Angewandte Chemie (International ed. in English)》2020,59(29):11977-11983
Rhodium nanoparticles immobilized on an acid‐free triphenylphosphonium‐based supported ionic liquid phase (Rh@SILP(Ph3‐P‐NTf2)) enabled the selective hydrogenation and hydrodeoxygenation of aromatic ketones. The flexible molecular approach used to assemble the individual catalyst components (SiO2, ionic liquid, nanoparticles) led to outstanding catalytic properties. In particular, intimate contact between the nanoparticles and the phosphonium ionic liquid is required for the deoxygenation reactivity. The Rh@SILP(Ph3‐P‐NTf2) catalyst was active for the hydrodeoxygenation of benzylic ketones under mild conditions, and the product distribution for non‐benzylic ketones was controlled with high selectivity between the hydrogenated (alcohol) and hydrodeoxygenated (alkane) products by adjusting the reaction temperature. The versatile Rh@SILP(Ph3‐P‐NTf2) catalyst opens the way to the production of a wide range of high‐value cyclohexane derivatives by the hydrogenation and/or hydrodeoxygenation of Friedel–Crafts acylation products and lignin‐derived aromatic ketones. 相似文献
2.
Deoximation in metal chloride ionic liquids based on 1‐alkyl‐3‐methylimidazolium and triethylene ammonium cations, such as AmimBr(Cl)‐MClx(A=ethyl, butyl, benzyl; M=Al, Fe, Cu, Sn and Zn; x=2, 3) and Et3NHCl‐FeCl3 were investigated under mild conditions. Ferrate chloride ionic liquid was proved to be an effective catalyst for deoximation of cyclohexanone oxime, exhibiting high conversion of oximes and selectivity to cyclohexanone. Good performance for the deoximation of other oximes such as salicylald oxime, acetone oxime, benzophenone oxime, 4‐nitrobenzald oxime, acetophenone oxime, 2‐chlorobenzaldehyde oxime, Acetald oxime, 2‐butanone oxime and (1R)‐camphor oxime was also achieved with bmimBr‐FeCl3 as catalyst and solvent. The deoximation was determined to carry out via acid‐catalytic hydrolysis and the reaction mechanism was proposed. 相似文献
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Bimetallic Nanoparticles in Supported Ionic Liquid Phases as Multifunctional Catalysts for the Selective Hydrodeoxygenation of Aromatic Substrates
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M. Sc. Lisa Offner‐Marko Dr. Alexis Bordet M. Sc. Gilles Moos Dr. Simon Tricard M. Sc. Simon Rengshausen Prof. Dr. Bruno Chaudret Dr. Kylie L. Luska Prof. Dr. Walter Leitner 《Angewandte Chemie (International ed. in English)》2018,57(39):12721-12726
Bimetallic iron–ruthenium nanoparticles embedded in an acidic supported ionic liquid phase (FeRu@SILP+IL‐SO3H) act as multifunctional catalysts for the selective hydrodeoxygenation of carbonyl groups in aromatic substrates. The catalyst material is assembled systematically from molecular components to combine the acid and metal sites that allow hydrogenolysis of the C=O bonds without hydrogenation of the aromatic ring. The resulting materials possess high activity and stability for the catalytic hydrodeoxygenation of C=O groups to CH2 units in a variety of substituted aromatic ketones and, hence, provide an effective and benign alternative to traditional Clemmensen and Wolff–Kishner reductions, which require stoichiometric reagents. The molecular design of the FeRu@SILP+IL‐SO3H materials opens a general approach to multifunctional catalytic systems (MM′@SILP+IL‐func). 相似文献
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研究了吸附时间、固液比、样品浓度、上样流速对N-甲基咪唑键合硅胶固定化离子液体(SilprMim)吸附黄酮类化合物性能的影响.结果表明,受试化合物在30 min内均达到吸附平衡;吸附效率随固液比增大而增加,随样品浓度增大而降低;吸附等温线与拟合的Langmuir模型吻合良好.SilprMim对染料木素、木犀草素及槲皮素的饱和吸附量分别为47.7, 52.5和63.2 mg/g,上样流速在0.5~1.5 mL/min范围内吸附效率达90%以上;甲醇洗脱染料木素、木犀草素及槲皮素的解吸率分别为86.1%, 83.3%和84.6%;解吸顺序为:染料木素、木犀草素、槲皮素.SilprMim对3种受试黄酮类化合物具有较强吸附和分离能力,有望应用于黄酮类天然产物的分离纯化. 相似文献
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Olga Bortolini Antonio De Nino Angelo Garofalo Loredana Maiuolo Beatrice Russo 《合成通讯》2013,43(16):2483-2487
Basic hydrogen peroxide and sodium perborate were found to be cheap and efficient alternatives for the conversion of primary and secondary nitro to carbonyl compounds (Nef reaction) in ionic liquids. 相似文献
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Summary: Functional cellulose shapes offer valuable properties for innovative application potentials in textile and medical products. Thereby excellent textile physiological properties of cellulose are allowed to be connected with novel application characteristics like bioactivity, electrical conductivity, heat storage or ability to adsorb liquids or gases. A very advantageous way to modify the properties of fibres, films or textile structures is to introduce particular additives via the Lyocell process. Regard to technical applications, functional additives will be able to incorporate themselves in the shape matrix and, in the case of using N-methylmorpholine-N-oxide monohydrate (NMMO) as solvent, implicate massive technological difficulties and deterioration of properties of the spinning dope. Beside a couple of limiting moments, ionic liquids (ILs) offer as direct solvents an excellent chance for physical modification of cellulose shapes. In contrast to NMMO, they exhibit a significantly higher thermal stability as well as a higher chemical resistance. ILs exhibit most widely a better dissolving capability for a number of different polymers. First results of the development of adsorber materials as well as novel bioactive fibres will be discussed and fibre characteristics will be given. 相似文献
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The Acidity of the HBr/AlBr3 System: Stabilization of Crystalline Protonated Arenes and Their Acidity in Bromoaluminate Ionic Liquids
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Dr. Franziska Scholz Dr. Daniel Himmel Lea Eisele Wiebke Unkrig Arthur Martens Peter Schlüter Prof. Dr. Ingo Krossing 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(20):7489-7502
Bulk protonated mesitylene, toluene, and benzene bromoaluminate salts were stabilized and characterized in the superacidic system HBr/n AlBr3 with NMR spectroscopy and X‐ray analysis of [HC6H3(CH3)3]+[AlBr4]? ( 1 ), [HC6H5(CH3)]+[AlBr4]? ( 2 ), and [C6H7]+[Al2Br7]??C6H6 ( 3 ). Protonation attempts in bromoaluminate ILs led to a complete protonation of mesitylene, and a protonation degree of up to 15 % for toluene in the IL BMP+[Al2Br7]?. Benzene could only be protonated in the more acidic IL BMP+[Al3Br10]?, with a degree of 25 %. Protonation attempts on aromatics provide evidence that the bromoaluminate ILs tolerate superacidic environments. On the basis of the absolute Brønsted acidity scale, quantum chemical calculations confirmed the superacidic properties, and rank the acidities in ILs down to a pHabs value of 164 with an error of less than one pH unit compared with experimental findings. The neat AlBr3/HBr system even may reach acidities down to pHabs 163. 相似文献
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Dipl.‐Chem. Benjamin Autenrieth Dr. Wolfgang Frey Prof. Michael R. Buchmeiser 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(44):14069-14078
A dicationic ruthenium–alkylidene complex [Ru(dmf)3(IMesH2)(?CH‐2‐(2‐PrO)‐C6H4)][(BF4)2] ( 1 ; IMesH2=1,3‐dimesitylimidazolin‐2‐ylidene) has been prepared and used in continuous metathesis reactions by exploiting supported ionic‐liquid phase (SILP) technology. For these purposes, ring‐opening metathesis polymerization (ROMP)‐derived monoliths were prepared from norborn‐2‐ene, tris(norborn‐5‐ene‐2‐ylmethyloxy)methylsilane, and [RuCl2(PCy3)2(CHPh)] (Cy=cyclohexyl) in the presence of 2‐propanol and toluene and surface grafted with norborn‐5‐en‐2‐ylmethyl‐N,N,N‐trimethylammonium tetrafluoroborate ([NBE‐CH2‐NMe3][BF4]). Subsequent immobilization of the ionic liquid (IL), 1‐butyl‐2,3‐dimethylimidazolium tetrafluoroborate ([BDMIM][BF4]), containing ionic catalyst 1 created the SILP catalyst. The use of a second liquid transport phase, which contained the substrate and was immiscible with the IL, allowed continuous metathesis reactions to be realized. High turnover numbers (TONs) of up to 3700 obtained in organic solvents for the ring‐closing metathesis (RCM) of, for example, N,N‐diallyltrifluoroacetamide, diethyl diallylmalonate, diethyl di(methallyl)malonate, tert‐butyl‐N,N‐diallylcarbamate, N,N‐diallylacetamide, diphenyldiallylsilane, and 1,7‐octadiene, as well as in the self‐metathesis of methyl oleate, could be further increased by using biphasic conditions with [BDMIM][BF4]/heptane. Under continuous SILP conditions, TONs up to 900 were observed. Due to the ionic character of the initiator, catalyst leaching into the transport phase was very low (<0.1 %). Finally, the IL can, together with decomposed catalyst, be removed from the monolithic support by flushing with methanol. Upon reloading with [BDMIM][BF4]/ 1 , the recycled support material again qualified for utilization in continuous metathesis reactions. 相似文献
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Kaija Põhako-Esko Triinu Taaber Kristjan Saal Rünno Lõhmus Ilmar Kink Uno Mäeorg 《合成通讯》2013,43(21):2846-2852
A new method for the synthesis of polymerizable ionic liquids bearing a methacrylate moiety was developed with the aim to avoid premature polymerization of synthesized compounds. Spacer length between the imidazolium cation and the polymerizable functional group varied from 2 to 10 carbon atoms. Different 1-(n-hydroxyalkyl)-3-methylimidazolium bromides and 1-[n-(methacryloyloxy)-alkyl]-3-methylimidazolium bromides were obtained with very good yields (more than 90%). [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource: Full experimental and spectral details.] 相似文献
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《Journal of heterocyclic chemistry》2017,54(1):51-54
Synthesis of carbonyl diimidazole type of ionic liquids via silica supported and conventional methodologies under muffle furnace and refluxing condition, respectively, to give shorter reaction time and higher yield. We have studied the catalytic activities of our synthesized ionic liquids for polymerization reactions. 相似文献
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Yan An GAO Zhong Ni WANG Jin ZHANG Wan Guo HOU Gan Zuo LI* Bu Xing HAN* Feng Feng Lü Gao Yong ZHANG Key Laboratory of Colloid Interface Chemistry 《中国化学快报》2005,16(7):963-966
The surfactant TX-100 can be dissolved in ionic liquid bmimPF6 and decrease the surface tension of 1-buty1-3-methylimidazolium hexafluorophosphate (bmimPF6) solutions. Here, we confirmed that in this new system, the pure solvents need rearrangement at the air-wate rinterface at the initial stage. The dynamic surface tension (DST) study shows that at the initial adsorption stage, the adsorption model of surfactant accords with the diffusion-controlled adsorption mechanism, and the dilute ionic liquids solutions is further close to the diffusion-controlled adsorption. 相似文献
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The targeted catalytic transfer hydrodeoxygenation (CTHDO) of vanillin (VAN) to 2-methoxy-4-methylphenol (MMP) holds promise as a noteworthy subject in the domain of bio-oil utilization, offering potential as a future biofuel and finding versatile use in fragrances and pharmaceutical industry. In this study, stable, cost-effective Ni nanoparticles supported on montmorillonite (MMT) clay was synthesized for eco-friendly, alcohol-mediated CTHDO of VAN to MMP. The Ni(10 %)/MMT catalyst achieved >99 % VAN conversion and 95.2 % MMP selectivity using isopropanol (IPA) as a solvent and hydrogen donor. Characterization encompassing PXRD, SEM, TEM, and XPS confirmed successful Ni integration onto MMT. NH3-TPD, pyridine-IR, and H2-TPR analysis evaluated catalyst surface acidity and reducibility. The synergy between surface-modulated acidity of MMT and Ni nanoparticles collectively facilitated IPA and VAN activation, driving CTHDO performance. The Ni(10 %)/MMT catalyst displayed sustained activity over five recycles. Its exceptional stability and performance underscore its potential as an eco-friendly, sustainable, non-noble transition metal-based catalyst for the hydrogenating lignin bio-oil model compounds, contributing to greener catalytic advancements. 相似文献
16.
Babasaheb P. Bandgar Vaibhav S. Sadavarte Lavkumar S. Uppalla Suresh V. Patil 《Monatshefte für Chemie / Chemical Monthly》2003,134(3):425-428
Summary. Treatment of 3,4-dihydro-2H-pyran with various alcohols and phenols in the presence of a catalytic amount of anhydrous calcium chloride in dichloromethane
furnished tetrahydropyranyl ethers under almost neutral conditions.
Corresponding author. E-mail: bandgar_bp@yahoo.com
Received January 25, 2002; accepted (revised) March 20, 2002 相似文献
17.
Kecheng Jie Nicole Onishi Jennifer A. Schott Ilja Popovs De‐en Jiang Shannon Mahurin Sheng Dai 《Angewandte Chemie (International ed. in English)》2020,59(6):2268-2272
Porous liquids are a type of porous materials that engineer permanent porosity into unique flowing liquids, exhibiting promising functionalities for a variety of applications. Here a Type I porous liquid is synthesized by transforming porous organic cages into porous ionic liquids via a supramolecular complexation strategy. Simple physical mixing of 18‐crown‐6 with task‐specific anionic porous organic cages affords a porous ionic liquid with anionic porous organic cages as the anionic parts and 18‐crown‐6/potassium ion complexes as the cationic parts. In contrast, mixing of 15‐crown‐5 and anionic porous organic cages in a 2:1 ratio gives only solids, while the addition of excess 15‐crown‐5 affords a Type II porous liquid. The permanent porosity in the cage‐based porous liquids has been also confirmed by molecular simulation, positron (e+) annihilation lifetime spectroscopy, and enhanced gas sorption capacity compared with pure crown ethers. 相似文献
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Encapsulation of a Catalytic Imidazolium Salt into Avidin: Towards the Development of a Biohybrid Catalyst Active in Ionic Liquids
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Vincent Gauchot Dr. Mathieu Branca Prof. Dr. Andreea Schmitzer 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(6):1530-1538
Herein, we report the development of biohybrid catalysts that are capable of catalyzing the aldol reaction. The use of biotinylated imidazolium salts in combination with racemic or enantiomerically pure catalytic anions allowed us to study the adaptive and cooperative positioning of the anionic catalyst inside the protein. Supramolecular encapsulation of the biotinylated catalyst into avidin resulted in good selectivity for the aldol reaction performed in ionic liquid/water mixtures. 相似文献
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微波促进酸性离子液体催化水杨酸酯化 总被引:2,自引:0,他引:2
用自制的硫酸氢1-甲基-3-(3-磺酸基丙基)咪唑([MIMPS]HSO4)酸性离子液体作为水杨酸与醇的酯化反应催化剂,考察了温度、时间、物料配比和离子液体用量等因素对酯化反应的影响,优化的最佳反应条件为: 微波辐射时间20 min,反应温度95 ℃,醇与酸摩尔比3∶1(水杨酸的量为0.02 mol),[MIMPS]HSO4用量10 mmol,水杨酸甲酯的产率和选择性分别为91.9%和99.0%。 离子液体回收循环使用4次,催化效率不变。 与热催化酯化反应相比,微波辐射可缩短反应时间;水杨酸与不同碳链醇的酯化产率随着碳链的增加而降低,同碳链的伯醇酯化率比仲醇高。 相似文献
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采用溶胶凝胶法制备了一系列硅胶负载型离子液体催化剂(IL/sg),并成功应用于甲醛与苯乙烯及其衍生物的Prins反应中.利用红外光谱(FT-IR)、元素分析(EA)和氮气吸附-脱附等对催化剂结构进行了表征.研究表明,磺酸功能化离子液体1-甲基-3-丁磺酸基咪唑硫酸氢盐固载得到的负载型催化剂(Bs MIm HSO4/sg)表现出最佳的催化活性.在催化剂投料量为烯烃的3%,甲醛与烯烃摩尔比为4∶1,80℃下反应8 h,苯乙烯转化率达到了100%,产物选择性为90%.催化剂经简单的过滤分离后重复使用5次,仍保持良好的催化活性.此外,该催化体系具有较好的底物适用性. 相似文献