共查询到20条相似文献,搜索用时 31 毫秒
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Ryosuke Yamada Kazunori Nakashima Nanami Asai-Nakashima Wataru Tokuhara Nobuhiro Ishida Satoshi Katahira Noriho Kamiya Chiaki Ogino Akihiko Kondo 《Applied biochemistry and biotechnology》2017,182(1):229-237
Among the many types of lignocellulosic biomass pretreatment methods, the use of ionic liquids (ILs) is regarded as one of the most promising strategies. In this study, the effects of four kinds of ILs for pretreatment of lignocellulosic biomass such as bagasse, eucalyptus, and cedar were evaluated. In direct ethanol fermentation from biomass incorporated with ILs by cellulase-displaying yeast, 1-butyl-3-methylimidazolium acetate ([Bmim][OAc]) was the most effective IL. The ethanol production and yield from [Bmim][OAc]-pretreated bagasse reached 0.81 g/L and 73.4% of the theoretical yield after fermentation for 96 h. The results prove the initial concept, in which the direct fermentation from lignocellulosic biomass effectively promoted by the pretreatment with IL. 相似文献
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Navjeet Kaur 《Phosphorus, sulfur, and silicon and the related elements》2019,194(3):165-185
Some organic solvents are highly toxic, flammable, and even explosive. In particular, high vapor pressures and toxicity of certain volatile organic solvents may cause significant environmental problems. Therefore, alternative solvents or media with tunable and versatile solvation properties for conducting chemical reactions and materials synthesis have been actively sought. Ionic liquids have numerous applications not only as environmentally benign reaction media, but also as catalysts and reagents. Due to the increase of environmental consciousness in chemical research and industry, the challenge for a sustainable environment calls for clean procedures that avoid the use of harmful organic solvents. Due to the special properties of ILs (ionic liquids) such as wide liquid range, good solvating ability, negligible vapor pressure, non-inflammability, non-volatility, environment friendly medium, high thermal stability, good stability in air and moisture, easy recycling and rate promoters etc. they are used in organic synthesis. Therefore, ionic liquids have attracted the attention of chemists and act as catalyst and reaction medium in organic reactions with high activity. Highly efficient methods are explored for the preparation of S-heterocycles with the application of ILs as catalyst and reaction medium. 相似文献
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Prof. Dr. Akio Kamimura Dr. Takuji Kawamoto Prof. Dr. Kenta Fujii 《Chemical record (New York, N.Y.)》2023,23(8):e202200269
Plastics are wonderful materials that have modernized our daily life; however, importance of effective recycling of plastics is gradually recognized widely. In this account, we describe our discovery of new and efficient methods for the chemical recycling of plastics using ionic liquids (ILs). Since the chemical recycling usually requires high temperature conditions to breakdown chemical bonds in polymeric materials, we thought that less-flammability and non-volatility of ionic liquids are the most suitable physical properties for this purpose. Ionic liquids successfully depolymerized polyamides and unsaturated polyesters smoothly and corresponding monomeric materials were obtained in good yields. To the best of our knowledge, this was the first use of Ionic liquids for such reactions. However, we encountered another difficult problem-separation. To solve the problem, we developed solubility-switchable ionic liquids, a new type of ionic liquids in which solubility is readily changed using the chemistry of protective groups. Conversion between hydrophilic and lipophilic forms was readily achieved using a simple chemical treatment under mild conditions, and the complete separation of products was achieved by liquid-liquid-extraction. The robustness of either form unlocks their wide use as reaction solvents. 相似文献
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《Comptes Rendus Chimie》2007,10(3):152-177
Over the last years, interest involving ionic liquids (ILs) used as reaction medium for homogeneous enantioselective catalysis has exponentially expanded. In many cases, the use of ILs provides several advantages over reactions in organic solvents in terms of activity and enantioselectivity. Even more important, the catalyst immobilization in IL can avoid its leaching and consequently favour its recycling. This review deals with recent advances in the investigation of these new solvents in asymmetric catalysis. We go over enzymes, chiral organocatalysts and metal complexes containing chiral ligands used in enantioselective processes using ionic liquids, with special emphasis on the catalyst reuse and also the separation of organic products. 相似文献
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Prof. Roger A. Sheldon 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(37):12984-12999
In this Minireview, the state of the art in the use of ionic liquids (ILs) and deep eutectic solvents (DESs) as alternative reaction media for biocatalytic processes and biomass conversion is presented. Initial, proof‐of‐concept studies, more than a decade ago, involved first‐generation ILs based on dialkylimidazolium cations and non‐coordinating anions, such as tetrafluoroborate and hexafluorophosphate. More recently, emphasis has switched to more environmentally acceptable second‐generation ILs comprising cations, which are designed to be compatible with enzymes and, in many cases are derived from readily available, renewable resources, such as cholinium salts. Protic ionic liquids (PILs), prepared simply by mixing inexpensive amines and acids, are particularly attractive from both an environmental and economic viewpoint. DESs, prepared by mixing inexpensive salts with, preferably renewable, hydrogen‐bond donors such as glycerol and amino acids, have also proved suitable reaction media for biocatalytic conversions. A broad range of enzymes can be used in ILs, PILs and DESs, for example lipases in biodiesel production. These neoteric solvents are of particular interest, however, as reaction media for biocatalytic conversions of substrates that have limited solubility in common organic solvents, such as carbohydrates, nucleosides, steroids and polysaccharides. This has culminated in the recent focus of attention on their use as (co)solvents in the pretreatment and saccharification of lignocellulose as the initial steps in the conversion of second‐generation renewable biomass into biofuels and chemicals. They can similarly be used as reaction media in subsequent conversions of hexoses and pentoses into platform chemicals. 相似文献
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In the past decade, ionic liquids (ILs) have received enormous interest as solvents for cellulose. They have been studied intensively for fractionation and biorefining of lignocellulosic biomass, for dissolution of the polysaccharide, for preparation of cellulosic fibers, and in particular as reaction media for the homogeneous preparation of highly engineered polysaccharide derivatives. ILs show great potential for application on a commercial scale regarding recyclability, high dissolution power, and their broad structural diversity. However, a critical analysis reveals that these promising features are combined with serious drawbacks that need to be addressed in order to utilize ILs for the efficient synthesis of cellulose derivatives. This review presents a comprehensive overview about chemical modification of cellulose in ILs. Difficulties encountered thereby are discussed critically and current as well as future developments in this field of polysaccharide research are outlined. 相似文献
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The facile syntheses of 1,2- and 3,5-cyclic sulfite and sulfate furanoside diesters were conducted in molecular solvents and ionic liquids in the presence of immobilised morpholine. Molecular solvents and ionic liquids performed similarly with regards to overall yields. However, the use of ILs allowed for the reactions to be carried out under atmospheric conditions and showed good recyclability. Additionally, increases in product stability was achieved in ILs over organic solvents, in particular, in bis{(trifluoromethanesulfonyl)imide} and trispentafluoro-ethyltrifluorophosphate-based ionic liquids, which were also excellent media to control the hydrolysis of thionyl chloride and sulfuryl chloride. 相似文献
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Stefan Baj 《合成通讯》2013,43(14):2385-2391
Cyclic ketones have been efficiently oxidized with hydrogen peroxide using acidic ionic liquids (ILs) as solvents. This is a new method for the synthesis of lactones with high yields that does not utilize any additional catalysts and enables ILs to be recycled. 相似文献
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Juliusz Pernak Anna ?wierczyńskaMariusz Kot Filip WalkiewiczHieronim Maciejewski 《Tetrahedron letters》2011,52(33):4342-4345
Pyrylium salts represent a new group of ionic liquids (ILs) containing a positive charge on the oxygen atom. The novel ILs were obtained starting with 4-pyrones from petroleum feedstock and renewable resources and sulfonic acids. The use of carboxylic acids instead of salts resulted in the formation of cocrystals. The synthesized pyrylium ionic liquids were stable in air and in contact with water and common organic solvents. The permanganate indices which are characteristic for prepared sulfonates were also investigated. The pyrylium ionic liquids were useful as immobilizers and dissolving agents in hydrosilylation reactions. 相似文献
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Catalytic reactions in two liquid phases containing ionic liquids (ILs), in which organic reactions proceed in the ILs phase and products are extracted to the other liquid phase, are efficient and environmentally benign. This short review briefly reports the development of catalytic application in biphasic systems containing ILs in the last two years. Recent progress for the functionalization of ILs themselves and combinations of homogeneous and heterogeneous catalysts with ILs are described. Prospects and future challenges are also addressed. 相似文献
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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。 相似文献
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Metal nanoparticles (MNPs) with a small diameter and narrow size distribution can be prepared by H(2) reduction of metal compounds or decomposition of organometallic species dissolved in ionic liquids (ILs). MNPs dispersed in ILs are catalysts for reactions under multiphase conditions. These soluble MNPs possess a pronounced surfacelike rather than single-site like catalytic properties. In other cases the MNPs are not stable and tend to aggregate or serve as reservoirs of mononuclear catalytically active species. 相似文献
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M. Dabiri P. Salehi M. Baghbanzadeh M. Shakouri S. Otokesh T. Ekrami R. Doosti 《Journal of the Iranian Chemical Society》2007,4(4):393-401
Dihydropyrimidinones, bis(indolyl)methanes, and N-alkyl and N-arylimides were synthesized efficiently under mild reaction conditions in the presence of two types of ionic liquids. In each section, effects of different ILs on the yield of reactions were investigated. The use of ionic liquids offer improvements for the synthesis of title compounds with regard to the yield of products, simplicity in operation, short reaction times and green aspects by avoiding toxic catalyst and organic solvents. 相似文献