共查询到20条相似文献,搜索用时 15 毫秒
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《分离科学与技术》2012,47(18):2847-2855
The most commonly studied classes of ionic liquids (ILs) comprise relatively large and asymmetric heterocyclic cations (e.g., diakylimidazolium or N-alkylpyridinium) in combination with any of a wide variety of inorganic (e.g., BF4?, Cl?) or organic (e.g., bis[(trifluoromethyl- sulfonyl)imide], Tf2N?) anions. Recently it has been shown that ILs can also be formed by complexation reactions of metal cations (e.g., Li+, as its Tf2N? salt) with various neutral ligands (e.g., cyclohexano-15-crown-5 or alkylamines). Because the upper limit of the useful temperature range of any IL is governed by its thermal stability, and because the thermal stability of a neutral ligand (i.e., its propensity to either volatilize or decompose) is of obvious importance in determining that of an IL prepared from it, a systematic examination of the thermal properties of a series of macrocyclic polyethers of potential utility in the synthesis of new ILs has been undertaken. The results show that the temperature corresponding to the onset of mass loss upon heating (i.e., evaporation and/or decomposition) varies with the ring size, substitution, nature of the donor atoms, and stereochemistry of the macrocycle, but is most strongly influenced by the molecular weight and aromatic content of the compound. 相似文献
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The dissolution of petroleum asphaltenes with ionic liquids is studied for the first time. The results show that the ionic liquids could be used as novel solvents for asphaltenes. The important parameters governing the ability of ionic liquids for dissolution of asphaltenes are discussed. It is found that, the ionic liquids based on the cations containing a conjugated aromatic core or the anions which are strong hydrogen bond acceptors are most effective, whereas the ionic liquids containing 'non coordinating' anions such as [BF4]^- and [PF6]^- are nonsolvents for asphaltenes. Increase in the effective anion charge density enhances the ability of ionic liquids to break the extensive asphaltene associations and thus enhances the solubility of asphaltenes in the ionic liquid. The dissolution ability of ionic liquid decreases apparently with increasing the substituted alkyl chain length of its cationic head ring. Temperature is found to play an important role on dissolution of asphaltenes, and the dissolution can be significantly imoroved bv microwave heatinz. 相似文献
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Dr. Ricardo Ferraz Prof. João Costa‐Rodrigues Prof. Maria H. Fernandes Dr. Miguel M. Santos Dr. Isabel M. Marrucho Prof. Luís Paulo N. Rebelo Prof. Cristina Prudêncio Prof. João Paulo Noronha Dr. Željko Petrovski Dr. Luís C. Branco 《ChemMedChem》2015,10(9):1480-1483
Significant antiproliferative effects against various tumor cell lines were observed with novel ampicillin salts as ionic liquids. The combination of anionic ampicillin with appropriate ammonium, imidazolium, phosphonium, and pyridinium cations yielded active pharmaceutical ingredient ionic liquids (API‐ILs) that show potent antiproliferative activities against five different human cancer cell lines: T47D (breast), PC3 (prostate), HepG2 (liver), MG63 (osteosarcoma), and RKO (colon). Some API‐ILs showed IC50 values between 5 and 42 nM , activities that stand in dramatic contrast to the negligible cytotoxic activity level shown by the ampicillin sodium salt. Moreover, very low cytotoxicity against two primary cell lines—skin (SF) and gingival fibroblasts (GF)—indicates that the majority of these API‐ILs are nontoxic to normal human cell lines. The most promising combination of antitumor activity and low toxicity toward healthy cells was observed for the 1‐hydroxyethyl‐3‐methylimidazolium–ampicillin pair ([C2OHMIM][Amp]), making this the most suitable lead API‐IL for future studies. 相似文献
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《分离科学与技术》2012,47(2):189-203
The development of applications of ionic liquids in extraction processes stretches back to the mid-1960s when the first studies on ionic liquid- based extractions were published. Since then, the interest of both academics and the industrial community on the development of ionic liquids-based technologies is continuously growing. The main driving force of ionic liquid engineering is to combine their “environmentally friendly” properties (e.g., extremely low vapor pressure) and their unique reactivity and miscibility behavior in order to improve the current “state of the art” technologies. The focus of this review is on the application of ionic liquid in heavy metal extraction processes. The critical aspects of their journey from academic curiosity towards industrial application are highlighted. 相似文献
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Nanjappan Gunasekaran 《Advanced Synthesis \u0026amp; Catalysis》2015,357(9):1990-2010
Selective aerobic oxidation reactions are most important and challenging transformations in both academic research and the chemical industry. Over the past decade, ionic liquids have gained recognition in the context of green organic synthesis as they are not only possible environmentally benign solvents but also serve as a liquid support or catalyst in various chemical processes. Hence, in recent years, there has been a growing interest in the development of aerobic oxidation reactions combined with ionic liquids and molecular oxygen or air which has led to the improvement of green catalytic systems capable of achieving high selectivity and yields. Thus, this review aims to give an overview of the most important advances made by in the field of aerobic oxidation reactions in combination with either molecular oxygen or air as oxidant and ionic liquids as solvent, liquid support or catalyst.
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Molecular dynamics simulation with an all-atom force field has been carded out on the two binary sys- tems of [bmim][PF6]-CO2 and [bmim][NO3]-CO2 to study the transport properties, volume expansion and micro- structures. It was found that addition of CO2 in the liquid phase can greatly decrease the viscosity of ionic liquids (ILs) and increase their diffusion coefficient obviously. Furthermore, the volume expansion of ionic liquids was found to increase with the increase of the mole fraction of CO2 in the liquid phase but less than 35% for the two simulated systems, which had a significant difference with CO2 expanded organic solvents. The main reason was that there were some void spaces inter and intra the molecules of ionic liquids. Finally, site to site radial distribution functions and corresponding number integrals were investigated and it was found that the change of microstructures of ILs bv addition CO2 had a great influence on the orooerties of ILs. 相似文献
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Kenneth R. Seddon 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1997,68(4):351-356
The use of room-temperature chloroaluminate(III) ionic liquids, specifically 1-butylpyridinium chloride–aluminium(III) chloride and 1-ethyl-3-methylimidazolium chloride–aluminium(III) chloride, as solvents for clean synthesis and catalytic processes, particularly those applicable to clean technology, is becoming widely recognised and accepted. The design principles for room-temperature ionic liquids, some of their properties, and the rationale for using these neoteric solvents, are discussed here, and an indication of the scope of these solvents for future industrial processes is given. © 1997 SCI. 相似文献
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The inexpensive and moisture-stable Lewis-acidic ionic liquids were prepared and applied for transesterification of soybean oil to biodiesel.The influences of molar ratio of methanol to soybean oil,reaction temperature and amount of ionic liquids were investigated.The transesterification of soybean oil to biodiesel catalyzed by choline chloride·xZnCl2 ionic liquids showed many advantages such as mild conditions and lower cost.On the other hand,the non-ideal yield and complicated separation between biodiesel and soybean oil were also investigated and analyzed.The improvement on the systems of choline chloride·xZnCl2 was proposed for further investigation. 相似文献
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Acidic ionic liquids (ILs) have been employed as extractant and catalyst in the oxidative desulfurization (ODS) process of fuels in recent years. Several Lewis acidic ionic liquids [C63MPy]Cl/nFeCl3 (molar fraction n = 0.5, 1, 2, 3) and [C6MIM]Cl/FeCl3 were prepared and used to remove the aromatic sulfur compounds dibenzothiophene and benzothiophene from fuels. In the ODS process, the used ILs acted as both extractant and catalyst with 30 wt % hydrogen peroxide aqueous solution as oxidant. The effects of Lewis acidity of ILs, IL's cation structure, molar ratio of O/S, reaction temperature, and different sulfur compounds on the sulfur removal of model oil were investigated. The results indicated that the sulfur removal for dibenzothiophene was affected by Lewis acidity of ILs and nearly reached 100 % by [C63MPy]Cl/FeCl3 at conditions of 298 K, IL/oil mass ratio of 1/3, O/S molar ratio of 4/1, in 20 min. The sulfur removal of real gasoline reached 99.7 % after seven ODS runs in the [C63MPy]Cl/FeCl3‐H2O2 system. 相似文献
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M. A. Tavanaie 《化学工程与技术》2013,36(11):1823-1837
Ionic liquids (ILs) with their special characteristics such as low melting point, high thermal stability, electrical conductivity, and good solubility in different chemical liquids, are widely used as new solvents for a large range of inorganic, organic, and polymeric materials. The development of ILs created a great untapped potential for commercial and academic applications to increase operating efficiencies of many chemical processes, including the processing of textiles. A summarizing introduction about ILs, their characterization, the general applications, and the major challenges is presented, followed by previous researches on using ILs for textile fiber formation and modification of their properties. 相似文献
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Yanlong Gu Juan Zhang Zhiying Duan Youquan Deng 《Advanced Synthesis \u0026amp; Catalysis》2005,347(4):512-516
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. 相似文献
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Identification of ionic liquids with low toxicity is paramount for applications in various domains. Traditional approaches used for determining the toxicity of ionic liquids are often expensive, and can be labor intensive and time consuming. In order to mitigate these limitations, researchers have resorted to using computational models. This work presents a probabilistic model built from deep kernel learning with the aim of predicting the toxicity of ionic liquids in the leukemia rat cell line (IPC-81). Only open source tools, namely, RDKit and Mol2vec, are required to generate predictors for this model; as such, its predictions are solely based on chemical structure of the ionic liquids and no manual extraction of features is needed. The model recorded an RMSE of 0.228 and of 0.943. These results indicate that the model is both reliable and accurate. Furthermore, this model provides an accompanying uncertainty level for every prediction it makes. This is important because discrepancies in experimental measurements that generated the dataset used herein are inevitable, and ought to be modeled. A user-friendly web server was developed as well, enabling researchers and practitioners ti make predictions using this model. 相似文献
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Jakub Suchodolski Joanna Feder-Kubis Anna Krasowska 《International journal of molecular sciences》2021,22(14)
Infections with Candida spp. are commonly found in long-time denture wearers, and when under immunosuppression can lead to stomatitis. Imidazolium ionic liquids with an alkyl or alkyloxymethyl chain and a natural (1R,2S,5R)-(−)-menthol substituent possess high antifungal and antiadhesive properties towards C. albicans, C. parapsilosis, C. glabrata and C. krusei. We tested three compounds and found they disturbed fungal plasma membranes, with no significant hemolytic properties. In the smallest hemolytic concentrations, all compounds inhibited C. albicans biofilm formation on acrylic, and partially on porcelain and alloy dentures. Biofilm eradication may result from hyphae inhibition (for alkyl derivatives) or cell wall lysis and reduction of adhesins level (for alkyloxymethyl derivative). Thus, we propose the compounds presented herein as potential anti-fungal denture cleaners or denture fixatives, especially due to their low toxicity towards mammalian erythrocytes after short-term exposure. 相似文献