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合成了具有钳子型的双咪唑阳离子核的室温离子液体2,它的相转变温度为-51℃,热力学分解温度为412℃,利用该离子液体作反应溶剂研究了不同钯催化剂PdCl2,Pd(OAc)2,Pd-NHC配合物3存在下的Suzuki偶联反应.结果表明:在NaOAc作碱,0.5 mol%的Pd-NHC配合物3存在下溴代苯衍生物与苯硼酸反应具有较高的活性,产率可以达到85%以上,Pd-NHC配合物3催化剂能更好地负载在钳子型双阳离子核室温离子液体2中,该反应体系能重复循环使用多次,且分离简单、重现性强、环境友好. 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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氯铝酸离子液体介质中醚化反应的研究 总被引:3,自引:0,他引:3
在1-烷基吡啶、1-甲基-3-烷基咪唑季铵盐或盐酸三甲铵与无水AlCl3构成的室温离子液体反应介质中,尝试进行了叔丁醇的醚化反应.结果表明,在中性或碱性氯铝酸离子液体中,叔丁醇与甲醇、乙醇、丙醇、丁醇或戊醇在80~140℃反应6~12h,可以得到较高的醇转化率和醚选择性,而且产物叔丁基醚和离子液体系分层,便于分离. 相似文献
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离子液体催化甲苯选择性羰基化反应合成对甲基苯甲醛 总被引:2,自引:0,他引:2
考察了卤化1-甲基-3-丁基咪唑氯铝酸盐类室温离子液体对甲苯选择性羰基化反应合成对甲基苯甲醛的催化性能. 采用乙腈探针红外光谱法测定了离子液体的酸类型(Brnsted/Lewis酸),并指示了离子液体的Lewis酸强度. 研究了离子液体的酸强度、反应温度、反应时间和CO压力的影响. 结果发现,该类离子液体对甲苯选择性羰基化反应的催化活性明显高于传统的B-L复合液体酸类和固体超强酸类催化剂; 使用离子液体催化剂显著地提高了甲苯选择性羰基化合成对甲基苯甲醛的产率,简化了产物与催化剂的分离. 当控制反应温度为50 ℃, CO压力为4.0 MPa, 反应时间为4 h时, [bmim]Br/AlCl3催化甲苯的转化率可达96%,目标产物对甲基苯甲醛的产率达86%. 相似文献
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氯铝酸室温离子液体系中HCl促进的苯的烷基化反应研究 总被引:19,自引:0,他引:19
研究了少量HCL调变的氯铝酸室温离子液体超强酸催化体系中,苯与碳-12烯以及氯甲烷的烷基化反应,对于前一反应,以溶有HCL的氯铝酸室温离子液体为催化剂与没有HCL的相比,反应的产物分布不同,而后一反应过程中有HCL生成,与纯ALCL3作催化剂相比,催化活性显著提高,实验结果还表明,生成的烷基化产物不溶于离子液体,因而易于分离,催化剂可以重复使用。 相似文献
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与传统中性叔膦配体构建的过渡金属配合物相比,由离子型膦配体配位构建的过渡金属配合物具有典型的离子盐组成特点、独特的电子效应和几何构型。该类配合物中,不仅存在金属和配体间的配位作用,还存在正电荷的强吸电子效应和阴阳离子的静电作用,由此可以产生独特的催化性能。近年来,离子型过渡金属配合物的合成及其均相催化应用成为配位化学和均相催化研究中备受关注的领域。离子型过渡金属配合物的离子盐结构,使其在与室温离子液体溶剂结合使用时,离子型离子配体及其配合物能够严格被锁定在离子液体相,具有避免离子型离子配体及其配合物的流失、抑制其失活、并实现循环使用的优点,也成为均相催化固载化的绿色方法之一。本文综述了近十年发展的一类咪唑鎓基与膦配体中的磷原子毗邻的离子型膦配体的合成,及其相应Rh、Pd、Ru、Pt、Au、Ni、Cu等离子型配合物的构建,并介绍了它们在均相催化反应中的应用。 相似文献
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室温离子液体催化正戊烷异构化反应 总被引:3,自引:2,他引:1
采用无水三氯化铝与多种有机氯盐按照不同摩尔比合成了具有不同酸度和阴、阳离子结构的室温离子液体,考察了离子液体的结构和反应条件对正戊烷异构化反应的影响。结果表明,合成离子液体过程中,AlCl3与Et3NHCl摩尔比对离子液体的酸强度和催化性能有较大的影响。实验确定了正丁醇为异构化反应适宜的引发剂,其用量为正戊烷的2.5%;正戊烷异构化的优化反应条件为反应温度30℃,反应10h,搅拌器转速1500r/min。在此优化反应条件下,正戊烷的转化率与异构化率分别达到85.66%和92.86%。 相似文献
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在离子液体中,研究了CoL(钴希夫碱配合物)的电化学行为,并进一步探讨了其对氯苄还原以及PhCH_2Cl与CO_2反应的催化特性.CoL在离子液体中呈现一对由扩散控制的单电子可逆氧化还原峰,通过电化学行为研究发现,其氧化还原峰电位不易随金属有机配合物的配体和离子液体阴离子的变化而变化,并求得了相应的扩散系数.同时,循环伏安图表明该体系能对PhCH_2Cl的还原起催化作用,反应经历一个ECE过程,另外,该体系还能催化PhCH_2Cl与CO_2反应,通过恒电位电解得到(PhCH_2)_2CO,说明常温常压下,CO_2可以通过CoL催化在离子液体中进行固定,得到新的有机化合物。 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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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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Meihuan Yao Qing Li Yanqiu Xia Yongmin Liang 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2018,92(3):502-507
A series of novel ionic liquids based on naphthyl-functionalized imidazolium cation have been prepared. Their structure was characterized by NMR. The thermal stabilities of the prepared liquids were studied by thermal gravimetric analysis. The new ionic liquids containing NTf-2 anion display significantly higher thermal stabilities (>400°C). Anion exchange to PF-6, BF-4, and Br– decreases the thermal stabilities of such ionic liquids. Fluorescence and UV–Vis absorption spectroscopy were used to study the spectroscopic properties of the ionic liquids. Compared with common ionic liquids, the described ionic liquids provide robust fluorescence properties and remarkably increased UV–Vis absorption. This research may enrich the field of functionalized ionic liquids and provide a platform for extension of ionic liquid applications. 相似文献
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改性离子液体中异丁烷与丁烯的烷基化反应 总被引:16,自引:2,他引:16
向由无水三氯化铝和盐酸三乙基胺合成的离子液体中溶入不同过渡金属(铜、铁、锌等)离子,考察它们对离子液体催化异丁烷与丁烯烷基化反应性能的影响。结果表明:过渡金属离子的加入能不同程度地影响离子液体的催化性能。溶入Cu2+和Cu+后,离子液体的催化性能有显著的改善,当Cu2+的摩尔加入量为三氯化铝的5%时,烷基化油收率达到丁烯体积的178%,对C8的选择性为75%,烷基化油辛烷值(RON)为92.2,并且离子液体可以重复使用。 相似文献
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Wang C Luo H Li H Zhu X Yu B Dai S 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(7):2153-2160
Phenolic ionic liquids for the efficient and reversible capture of CO(2) were designed and prepared from phosphonium hydroxide and substituted phenols. The electron-withdrawing or electron-donating ability, position, and number of the substituents on the anion of these ionic liquids were correlated with the physicochemical properties of the ionic liquids. The results show that the stability, viscosity, and CO(2)-capturing ability of these ionic liquids were significantly affected by the substituents. Furthermore, the relationship between the decomposition temperature, the CO(2)-absorption capacity, and the basicity of these ionic liquids was quantitatively correlated and further rationalized by theoretical calculation. Indeed, these ionic liquids showed good stability, high absorption capacity, and low absorption enthalpy for CO(2) capture. This method, which tunes the physicochemical properties by making use of substituent effects in the anion of the ionic liquid, is important for the design of highly efficient and reversible methods for CO(2)-capture. This CO(2) capture process using diverse phenolic ionic liquids is a promising potential method for CO(2) absorption with both high absorption capacity and good reversibility. 相似文献
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离子液体萃取脱硫新工艺研究 总被引:36,自引:0,他引:36
探讨了不同离子液体在不同条件下通过萃取降低汽油中硫含量的可能性.结果表明,较长碳链的DMImBF4离子液体具有很好的深度脱硫性能,并且能够重复使用.同时,研究结果还表明离子液体可以同时降低低碳烯烃的含量,而低碳烯烃的存在可以促进离子液体对汽油中硫的萃取. 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