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将以磺化六亚甲基四胺([HMT-4PS])制备的阳离子与以杂多酸([HPA])制备的阴离子结合, 制备了一系列功能特异性离子液体催化剂([HMT-4PS][HPA]); 将其用于催化甲醇(MeOH)与丁二酸(SA)水溶液的直接酯化反应. 结果表明, 该系列离子液体在反应过程中以“乳状液”的形式均匀分散在体系中. 反应结束后, 通过降低体系极性即可实现催化剂的快速分离. 在合成的系列催化剂中, [HMT-4PS]3[PW]4表现出最佳的催化活性. 分别探讨了反应温度、 催化剂用量、 酸醇摩尔比和反应时间等因素对反应的影响, 确定了最优反应条件: 温度80 ℃, 催化剂用量5%(质量分数, 按丁二酸水溶液计), n(SA)∶n(MeOH)=1∶30, 反应时间8 h. 最优条件下丁二酸的转化率达到79.3%, 二酯选择性达到92.9%; 该催化剂重复使用5次后, 丁二酸转化率及二酯选择性仍分别保持在77%及90%以上. 相似文献
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本文首次将一系列含有不同酸性咪唑阳离子和不同杂多酸阴离子的杂多酸离子液体[C4mim]3PW12O40、[COOH-Cmim] 3PW12O40、[SO3H-C3mim]3PW12O40、[SO3H-C3mim]3PMo12O40和[SO3H-C3mim]4 SiW12O40作为催化剂,乙腈为萃取剂,H2O2为氧化剂,用于催化含二苯并噻吩、苯并噻吩及噻吩模型油的萃取氧化脱硫研究中.实验结果显示,杂多酸离子液体催化燃油脱硫性能不仅与阳离子的酸性强弱有关,而且与阴离子结构密切相关.阳离子的催化活性顺序为:[SO3H-C3mim]+>[COOH-Cmim]+>[C4mim]+;阴离子的催化活性顺序为PW12O403-> PMo12O403-> SiW12O404-.其中[SO3H-C3 mim]3 PW12O40催化活性最高,在60℃反应40min的条件下,二苯并噻吩的转化率约为100%,催化不同硫化物的转化率为:二苯并噻吩>苯并噻吩>噻吩.此外,该杂多酸离子液体循环使用5次催化活性仅略有下降. 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
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采用酸化-乙醚萃取法制备了不同钒取代数目的 Keggin结构的磷钨钒杂多酸,并进一步通过离子交换法合成了磺酸功能化的杂多酸离子液体催化剂,采用核磁、元素分析、红外、紫外、X射线衍射、热重-差示扫描、电位滴定等分析手段对所得样品进行了表征,考察了所得样品对氯乙酸和正戊醇的酯化反应性能和重复使用性能。结果表明,所制备的杂多酸离子液体是一种具有温度响应特性的无定型结构化合物,仍保留Keggin结构和较高的酸强度,该催化剂在反应温度下与反应物形成一相,而反应结束温度降低后,催化剂和产物又形成两相,通过简单的倾倒法就可以快速分离催化剂和反应产物。与杂多酸以及未磺酸化的杂多酸离子液体相比,磺酸功能化的杂多酸离子液体具有更高的酯催化活性。在优化的反应条件下,[PyPS]4PW11VO40(PyPS为1-(3-磺酸基)丙基吡啶)对氯乙酸的转化率可达到97.6%,重复使用4次后转化率为91.9%,而催化剂的结构未有明显变化。 相似文献
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离子液体的酸性测定及其催化的二苯醚/十二烯烷基化反应 总被引:20,自引:0,他引:20
采用乙腈探针红外光谱法测定了[bmim]Cl/AlCl3类离子液体的酸性.结果表明,乙腈可以区分离子液体的酸类型(Bronsted酸或Lewis酸),同时可以指示离子液体的Lewis酸强度.使用[bmim]Cl/AlCl3类离子液体催化二苯醚与十二烯的烷基化反应,研究了离子液体的酸强度、反应温度和醚烯比对反应的影响,并与AlCl3催化体系进行对比.结果发现,该离子液体对二苯醚与十二烯烷基化反应的催化活性明显高于AlCl3.使用离子液体作催化剂显著提高了烷基化反应的产率,简化了产物的分离与提纯,且对环境友好.当控制反应温度为80℃,原料醚烯摩尔比为7,并采用酸强度适中的离子液体时,目标产物单十二烷基二苯醚的产率接近90%. 相似文献
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An environmentally benign and highly efficient protocol for the transamidation of non-activated carboxamides with amines using heteropolyanion-based ionic liquids as catalysts under microwave-assisted and solvent-free conditions has been developed. As evaluated by the reactions of a structurally diverse set of amides and amines, the scope and utility of the transamidation proved to be quite general. Operational simplicity, solvent-free media, the potential reusability of catalysts and wide functional group tolerance are attractive features. This method provides a much improved protocol over the existing methods. 相似文献
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An eco-benign and highly efficient route for N-acylation of amines has been developed by treating amines with corresponding carboxylic acids in the presence of 2 mol % of heteropolyanion-based ionic liquids as catalysts under solvent-free conditions. This practical reaction could tolerate a wide range of substrates. Thus, various N-acylation products including N-acyl α-amino acid derivatives were obtained in moderate to excellent yields at 70 °C to 120 °C. Moreover, recycling studies revealed that heteropolyanion-based ionic liquids were easily reusable for this N-acylation. This method provides a green and much improved protocol over the existing methods. 相似文献
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E.I. Lozinskaya 《European Polymer Journal》2004,40(9):2065-2075
Ionic liquids (ILs) are subject to an enormous research effort due to their unique properties, such as non-volatility, high solution and reactivity ability, etc. For the first time ILs have been used as a solvent for preparing polymers via direct polycondensation. The influence of IL's nature and reaction parameters upon the polymer formulation has been investigated. It is shown that direct polycondensation is successfully proceeded in ILs and triphenyl phosphite (condensing agent) without any additional extra components, such as LiCl and pyridine, using in similar reactions in ordinary molecular solvents. Various polyamides (ηinh=0.11-1.10 dl/g), polyamide imides (ηinh=0.48-1.41 dl/g), -hydrazides (ηinh=0.56-0.60 dl/g) and polyhydrazides (ηinh=0.71-1.32 dl/g) have been obtained in quantitative yield and high molecular weight. 相似文献
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以碱性离子液体为催化剂,对碳酸二甲酯(DMC)和碳酸二乙酯(DEC)酯交换反应合成碳酸甲乙酯进行了研究.筛选出高催化活性的碱性离子液体1-丁基-3甲基咪唑丁酸盐([C4mim][CH3(CH2)2COO])为催化剂,详细考察了反应时间、温度、催化剂用量、原料配比等因素对酯交换反应的影响.实验结果表明,在反应温度为90℃,催化剂用量为6%(占反应物总质量百分数),n(DMC)∶n(DEC)=1.5∶1,反应时间为5h时,DEC的转化率高达48%.[C4mim][CH3(CH2)2COO]重复利用5次后仍保持较高的催化活性. 相似文献
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室温离子液体催化正己烷异构化反应的研究 总被引:1,自引:1,他引:1
由无水三氯化铝与盐酸三乙胺按照不同摩尔比合成了具有不同酸度的室温离子液体,并考察了其酸性以及对正己烷异构化反应的催化性能。结果发现,随着离子液体合成时AlCl3比例的增大,离子液体的酸性增强,且离子液体2AlCl3/Et3NHCl对正己烷异构化显示出优良的催化性能。针对离子液体2AlCl3/Et3NHCl,考察了反应时间、反应温度和催化剂用量(剂油体积比)对正己烷异构化反应的影响。结果表明,反应条件对异构烷烃选择性的影响不大,但是对原料转化率、异构烷烃产率和液体收率有较大的影响。离子液体催化正己烷异构化的最佳反应条件,反应温度为50℃,反应时间为45min,剂油体积比为1∶1。 相似文献
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Zuojun Wei Yong Huang Shuguang Deng Dipendu Saha Yingxin Liu Qilong Ren 《Reaction Kinetics and Catalysis Letters》2008,95(2):257-264
Alcoholysis of soybean isoflavone glucosides by butanol catalyzed by acidic ionic liquids was studied. The effects of the
ionic liquid catalyst type, catalyst concentration, reaction time and reaction temperature on glycoside conversions, and aglycons
yields were investigated. The optimum reaction conditions are found to be as follows: 0.036 g mL−1 of ionic liquid [BIM]HSO4 as catalyst, reaction temperature at 104±1°C, reaction time of 100 min. Under these optimum reaction conditions near complete
conversions of the three kinds of glycosides (daidzin, glycitin and genistin) are obtained. Furthermore, the kinetics parameters
for the alcoholysis were estimated. The activation energies of alcoholysis for the three kinds of isoflavone glucosides are
124 kJ mol−1, 67 kJ mol−1 and 115 kJ mol−1, respectively. 相似文献
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Hao Xu Liyang Pan Xiaomin Fang Baoying Liu Wenkai Zhang Minghua Lu Yuanqing Xu Tao Ding Haibo Chang 《Tetrahedron letters》2017,58(24):2360-2365
A series of novel N-methyl morpholine (Nmm) based ionic liquids with 1,2-propanediol group were synthesized and used as catalysts for Knoevenagel condensation at room temperature in water. Under the effect of the catalyst, various aldehydes or aliphatic ketones could react with a wide range of activated methylene compounds well, including malononitrile, alkyl cyanoacetate, cyanoacetamide, β-diketone, barbituric acid, 2-arylacetonitrile and thiazolidinedione. Furthermore, most of the products could be separated just by filtrating and washing with water. Additionally, the catalyst is recyclable and applicable for the large-scale synthesis. 相似文献