共查询到20条相似文献,搜索用时 31 毫秒
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Physical and electrochemical properties of 1-alkyl-3-methylimidazolium tetrafluoroborate for electrolyte 总被引:6,自引:0,他引:6
Three kinds of ionic liquids, 1-alkyl-3-methylimidazolium tetrafluoroborate (n=2–4), were prepared and fundamental properties of ionic liquids and those mixed with industrially used organic solvents (PC, GBL and AN) were investigated compared to solid salts, TEMABF4. It was found that degree of ionization of the ionic liquids were almost same as that of TEMABF4 from the conductivity measurement in diluted system of PC. The ionic liquids and the organic solvents intermingle with each other. Some enhancement in conductivity was observed compared to TEMABF4. 相似文献
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室温离子液体中水溶性铑膦配合物催化1-己烯氢甲酰化反应的研究 总被引:2,自引:0,他引:2
研究了水溶性膦配体铑配合物在若干离子液体中的1-己烯氢甲酰化反应性能.通过改变离子液体的阴阳离子结构,可使水溶性TPPTS-铑配合物在离子液体中表现出较高的卜己烯氢甲酰化反应活性和选择性;在[BMI]BF4离子液体中加入适量的水,可提高TPPTS-铑配合物的催化活性;在[BMI]BF4离子液体中,水/有机两亲性膦配体与铑形成的配合物,反应后催化剂与产物自动分层,实现催化剂的循环使用.本文结果表明,水溶性膦配体铑配合物的催化活性与其在离子液体中的溶解度密切相关. 相似文献
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Li-Juan Jia Yuan-Yuan Wang Hui Chen Yong-Kui Shan Li-Yi Dai 《Reaction Kinetics and Catalysis Letters》2005,86(2):267-273
Summary The alkylation of benzene with 1-hexene has been investigated in different triethylamine hydrochloride-ferric chloride (Et3NHCl-FeCl3) and triethylamine hydrochloride-aluminium chloride (Et3NHCl-AlCl3) ionic liquids. Both high catalyst activity and monoalkylation selectivity were observed for these two type of ionic liquids.
Systems prepared by modification with HCl in Et3NHCl-FeCl3ionic liquids prove to be very suitable solvents and catalysts for the reaction. When employing Et3NHCl-AlCl3ionic liquids as catalysts, the reaction takes place in biphasic mode with facile catalyst separation and catalyst recycling. 相似文献
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2-Azido-3,5-dichloropyridine and 2-azido-5-chloro-3-fluoropyridine were given by reaction of sodium azide with 2,3,5-trichloropyridine, 3,5-dichloro-2-fluoropyridine or 5-chloro-2,3-difluoropyridine in ionic liquids. 1,3-Dipolar cycloaddition of 2-azido-3,5-dichloropyridine or 2-azido-5-chloro-3-fluoropyridine to alkynes in ionic liquids afforded the corresponding 1,4,5-trisubstituted [1,2,3]-triazoles in good yields and regioselectivities. 相似文献
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ZhiGuoHU ShiLiSONG JianJiWANG LinYANG 《中国化学快报》2004,15(6):707-710
In this paper, the effect of ionic liquids on the CaCO3 crystal growth has been studied for the first time. The obtained CaCO3 crystals were charactcred by the X-ray diffraction and scanning electron micrographs. The results showed that the control ability of ionic liquids for CaCO3 crystals growth was dependent on the counter anion very much. 相似文献
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Temperature dependent molar conductances and fluidities of bisulfate and ethyl sulfate anion-based ionic liquids were measured. The extent of dissociation of the ionic liquids was estimated from the Walden plot in term of ionicity. The ionicity mainly depends on the magnitude of Coulombic forces, altered by the anion’s Lewis basicity. Aqueous solutions of aprotic ionic liquids, in general, possesses ionicity in the range of ≈70–99%. This article reveals that the substitution of the anion by bisulfate and ethylsulfate reduces the ionicity of aqueous solution of these ionic liquids to the range of 10–37%. This is very close to that exhibited by some of the protic ionic liquids and phosphonium based ionic liquids with sweetner anions. The concentration dependent molar conductance of these ionic liquids has been fitted to Mahiuddin and Ismail’s equation. To our surprise, the molar conductances of bisulfate-based aprotic ionic liquids are remarkably high, even though these ionic liquids possess lower ionicity. 相似文献
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新型1-烷基-2,3-二甲基咪唑六氟磷酸盐离子液体/过氧化氢酶电极电化学性能研究与应用 总被引:2,自引:0,他引:2
合成了5种新型1-烷基-2,3-二甲基咪唑六氟磷酸盐类离子液体,并以离子液体为介质制备空白电极及过氧化氢酶电极.采用循环伏安法研究电极电化学行为,结果表明离子液体有优良的电化学性质.离子液体空白电极的基体峰电流都在数nA范围内,电化学窗口大于4 V;不同离子液体酶电极的电化学行为存在明显差异.在5种离子液体中,仅有1-戊基-2,3-二甲基咪唑六氟磷酸盐能很好地保持酶活,呈现灵敏的电化学响应.此外,该酶电极还具有良好的稳定性,4 ℃保存30 天后,电化学性质没有明显变化.在0.1 mol/L的H3PO4缓冲溶液(pH 7.0)中,该酶电极还原峰电流随溶液中H2O2浓度的增加而增大.当H2O2浓度在3.17×10-6~12.4×10-6 mol/L之间,酶电极的还原峰电流符合线性关系,其检出限为1.1×10-6 mol/L.方法已用于环境水中痕量H2O2的测定. 相似文献
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Improving carbon dioxide solubility in ionic liquids 总被引:4,自引:0,他引:4
Muldoon MJ Aki SN Anderson JL Dixon JK Brennecke JF 《The journal of physical chemistry. B》2007,111(30):9001-9009
Previously we showed that CO2 could be used to extract organic molecules from ionic liquids without contamination of the ionic liquid. Consequently a number of other groups demonstrated that ionic liquid/CO2 biphasic systems could be used for homogeneously catalyzed reactions. Large differences in the solubility of various gases in ionic liquids present the possibility of using them for gas separations. More recently we and others have shown that the presence of CO2 increases the solubility of other gases that are poorly soluble in the ionic liquid phase. Therefore, a knowledge and understanding of the phase behavior of these ionic liquid/CO2 systems is important. With the aim of finding ionic liquids that improve CO2 solubility and gaining more information to help us understand how to design CO2-philic ionic liquids, we present the low- and high-pressure measurements of CO2 solubility in a range of ionic liquids possessing structures likely to increase the solubility of CO2. We examined the CO2 solubility in a number of ionic liquids with systematic increases in fluorination. We also studied nonfluorinated ionic liquids that have structural features known to improve CO2 solubility in other compounds such as polymers, for example, carbonyl groups and long alkyl chains with branching or ether linkages. Results show that ionic liquids containing increased fluoroalkyl chains on either the cation or anion do improve CO2 solubility when compared to less fluorinated ionic liquids previously studied. It was also found that it was possible to obtain similar, high levels of CO2 solubility in nonfluorous ionic liquids. In agreement with our previous results, we found that the anion frequently plays a key role in determining CO2 solubility in ionic liquids. 相似文献
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二苯醚烷基化反应中酸性离子液体的循环使用 总被引:3,自引:0,他引:3
使用酸性离子液体催化二苯醚与十二烯烷基化反应,考察了离子液体的失活原因,提出了循环使用离子液体的解决办法.在二苯醚与十二烯烷基化反应中, Lewis酸性离子液体不能多次循环使用的原因是离子液体与二苯醚相互作用导致具有催化活性的Al2Cl72-分解、流失.改变离子液体的阳离子不能从本质上解决其与二苯醚间的相互作用.适时补加损失量的AlCl3使离子液体的Lewis酸性得以恢复,可以解决体系中酸性离子液体循环使用问题,循环使用8次后产物产率仍保持90%左右. 相似文献
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After being hydrolyzed into corresponding hydrosoluble carboxylate by 1,1,3,3,-tetramethylguanidine (TMG), camptothecin was extracted via the aqueous two-phase systems composed of ionic liquid 1,1,3,3- tetramethylguanidinium(TMGM) carboxylate and K2CO3, and was regenerated at the final by dilute aqueous hydrochloric acid. Among the ionic liquids, TMGM benzoate showed the best effect, TMGM formate the worst, this results were consistent with the liposolubilities of different carboxylic acid components in the ionic liquids. Through two-step extraction of TMGM benzoate ionic liquid/K2CO3 aqueous two-phase under a favorable condition, camptothecin was obtained in a purity of 98.3% and a total yield of 85.1%, from the crude camptothecin extract with a purity of 14.2%. 相似文献
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超临界CO2/离子液体体系 总被引:2,自引:0,他引:2
超临界CO2和离子液体是两种具有优异性能的绿色化学试剂,本文介绍了将两者结合反应,分离体系的物化性质和多种绿色化学过程。利用超临界CO2可以广泛地萃取离子液体中的不挥发性化合物而不导致离子液体及其中催化剂的流失,在加氢、醛化、甲酰化等反应,分离过程中的应用表明,过程具有很好的反应分离特性和环境友好性,应用前景广阔。 相似文献
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Time-resolved fluorescence spectra and fluorescence anisotropy decay of 2-aminoquinoline (2AQ) have been measured in eight room-temperature ionic liquids, including five imidazolium-based aromatic ionic liquids and three nonaromatic ionic liquids. The same experiments have also been carried out in several ordinary molecular liquids for comparison. The observed time-resolved fluorescence spectra indicate the formation of pi-pi aromatic complexes of 2AQ in some of the aromatic ionic liquids but not in the nonaromatic ionic liquids. The fluorescence anisotropy decay data show unusually slow rotational diffusion of 2AQ in the aromatic ionic liquids, suggesting the formation of solute-solvent complexes. The probe 2AQ molecule is likely to be incorporated in the possible local structure of ionic liquids, and hence the anisotropy decays only through the rotation of the whole local structure, making the apparent rotational diffusion of 2AQ slow. The rotational diffusion time decreases rapidly by adding a small amount of acetonitrile to the solution. This observation is interpreted in terms of the local structure formation in the aromatic ionic liquids and its destruction by acetonitrile. No unusual behavior upon addition of acetonitrile has been found for the nonaromatic ionic liquids. It is argued that the aromaticity of the imidazolium cation plays a key role in the local structure formation in imidazolium-based ionic liquids. 相似文献
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Air and water stable ionic liquids in physical chemistry 总被引:1,自引:0,他引:1
Ionic liquids are defined today as liquids which solely consist of cations and anions and which by definition must have a melting point of 100 degrees C or below. Originating from electrochemistry in AlCl(3) based liquids an enormous progress was made during the recent 10 years to synthesize ionic liquids that can be handled under ambient conditions, and today about 300 ionic liquids are already commercially available. Whereas the main interest is still focussed on organic and technical chemistry, various aspects of physical chemistry in ionic liquids are discussed now in literature. In this review article we give a short overview on physicochemical aspects of ionic liquids, such as physical properties of ionic liquids, nanoparticles, nanotubes, batteries, spectroscopy, thermodynamics and catalysis of/in ionic liquids. The focus is set on air and water stable ionic liquids as they will presumably dominate various fields of chemistry in future. 相似文献
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Ionic liquids are a class of solvents widely studied in the literature for various applications. As a subclass of ionic liquids, redox ionic liquids can endow charge exchange properties (electrons transfer) to these electrolytes for electrochemical energy storage. In this review article, we propose to study this family of ionic liquids and suggest a chronological classification. We introduce five generations of redox ionic liquids with different basic compounds such as polyethylene glycol, ferrocene, different linker lengths, TFSI anion, and biredox ionic liquids. The versatility of the redox ionic liquids synthesis will be discussed as well as the fundamental and applied aspects of their use as electrolytes, which have high charge densities. The impact of the redox ionic liquids on the electrochemical mechanisms will be described. We also present how the redox shuttle effect, detrimental to supercapacitors, can be prevented while it can be used to improve lithium-ion batteries. 相似文献
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