共查询到20条相似文献,搜索用时 93 毫秒
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综述了离子液体在Heck反应、氧化反应、加氢还原反应、傅-克反应和醇的卤代反应中的应用。氯铝酸离子液体催化的合成丁基苯的傅-克反应中,室温下反应3m in即可反应完全,而在离子液体中进行的烯烃加氢反应只需反应6h。离子液体也能加快氧化反应的反应速度。 相似文献
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回顾了离子液体的发展阶段及作为一种新型的绿色环保有机化合物具有的一些优异性质,如低的饱和蒸气压、良好的溶解性、热稳定性、高电导率和宽的电化学窗口等。综述了离子液体的种类、构效关系及制备方法,介绍了离子液体在萃取分离方面的应用,作为溶剂在各类常见的有机反应中的影响和优势,包括氧化反应、Friedel-Crafts反应、Diels-Alder反应、碳-碳偶联反应、酯化反应、环氧化反应等。与传统催化剂进行比较,突出了不同类型的离子液体催化剂对不同催化反应效果的优势,指出了离子液体催化剂发展的趋势。提出了离子液体今后将突出在节能减排、非均相高效催化方面的应用前景。 相似文献
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咪唑类离子液体及其在生物催化中的应用 总被引:1,自引:0,他引:1
咪唑类离子液体的合成,概括了离子液体中生物催化反应的特点,重点介绍咪唑类离子液体在蛋白酶催化的反应、脂肪酶催化的反应、氧化还原酶催化的反应以及其它酶催化的反应中的应用。 相似文献
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离子液体中TS-1分子筛催化环己烷氧化反应 总被引:1,自引:0,他引:1
以离子液体[emim]BF4为反应介质,叔丁基过氧化氢(TBHP)为氧化剂,TS-1分子筛为催化剂,进行了环己烷选择性氧化反应研究.考察了氧化剂与环己烷物质的量比、反应时间、反应温度及离子液体/催化剂体系循环使用对环己烷氧化反应的影响.实验结果表明,在TBHP/环己烷物质的量比为2,反应温度为90 ℃,反应时间为18 h时,环己烷的转化率为13.2%,目的产物环己酮与环己醇的选择率高达97.6%.离子液体/催化剂体系循环使用4次后环己烷的转化率及氧化产物的收率略有降低. 相似文献
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离子液体在有机合成中的应用新进展 总被引:1,自引:0,他引:1
室温下的离子液体作为一种绿色、环保、可替代传统有机溶剂的新型溶剂受到了极大关注.总结了近年来离子液体在有机合成反应中的研究新进展,包括氧化反应、还原反应、Friedel-Crafts反应、Diels-Alder反应、Heck反应、硝化反应及其它合成反应. 相似文献
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高级氧化技术是近年来备受人们关注的印染废水处理技术,本文分析了印染废水的基本特征,并就高级氧化技术中的超临界水氧化技术、湿式氧化技术、臭氧氧化技术、电化学氧化技术、Fenton氧化技术、超声波处理技术和光催化氧化技术在印染废水中的应用做了阐述,介绍了各技术的基本原理和应用中优缺点,为高级氧化技术在处理印染废水的实际应用提供了理论依据。 相似文献
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废水高级氧化技术现状与研究进展 总被引:1,自引:0,他引:1
介绍了Fenton和Fenton类氧化法、超声氧化法、臭氧氧化法、光催化氧化法、超临界水氧化法等几种常用的高级氧化技术在废水处理中的现状,并展望了各个高级氧化技术今后的研究热点及主要发展方向. 相似文献
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近年来,水环境污染问题引起人们越来越多的重视。发展新型水处理技术,实现废水达标排放对国家的可持续发展具有重要作用。高级氧化法因其具有氧化彻底、速度快、效率高、无公害等特点而被关注。文章综述了Fenton试剂氧化法、臭氧氧化法、湿法空气氧化法、催化湿法氧化法、光化学氧化法等处理废水的原理和进展。高级氧化技术在废水处理领域具有广阔的应用前景,但要真正实现其工业化应用,在降低成本的同时,还需加强其机理研究。 相似文献
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Kinetics of Thermal, Passive Oxidation of Nicalon Fibers 总被引:1,自引:0,他引:1
Yuntian T. Zhu Seth T. Taylor Michael G. Stout Darryl P. Butt Terry C. Lowe 《Journal of the American Ceramic Society》1998,81(3):655-660
The oxidation of Nicalon fibers is a concern, because of its potential as a reinforcement of high-temperature composites, whose service conditions involve high-temperature, oxidizing environments. Two limiting types of oxidation mechanisms are often used to describe the kinetics: chemical-reaction-controlled oxidation, at small oxide thicknesses, and diffusion-controlled oxidation, at large oxide thicknesses. Neither mechanism can satisfactorily describe the intermediate region where the oxidation kinetics are controlled jointly by both the chemical reaction rate at the interface and the diffusion of oxygen through the oxide layer. To describe the entire oxidation process with a general relationship, one must consider all stages of the oxidation process, namely (i) adsorption of oxygen at the outer surface of the oxide, (ii) diffusion of oxygen from the outer surface toward the interface where oxidation occurs, and (iii) reaction at the interface to form a new layer of oxide. Previously, a very useful general relationship was derived for the oxidation kinetics for a flat plate, which could account for all three stages of oxidation. However, that equation is inadequate to describe the oxidation of cylindrical fibers, because the effective area for oxygen diffusion changes along the diffusion path and the oxidation interfacial area decreases as the oxide thickness increases for cylindrical fibers. In this paper, we have derived a general kinetic relationship for the oxidation of cylindrical fibers, which can account for all stages of oxidation. Comparison of the theory with experimental data of Nicalon fibers shows good agreement. 相似文献
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The performance of mixture of methanol and ethylene glycol (EG) oxidation has been studied on both Pt and Pd electrodes in alkaline medium. The activity of EG oxidation is better than that of methanol oxidation and the stability of EG oxidation is better than that of methanol and ethanol oxidation on the Pd electrode. The onset potential for ethanol oxidation is more negative 200 mV than that of EG, however the stability of EG oxidation on the Pd electrode is better than that of ethanol oxidation. The performance of methanol oxidation improves pronouncedly by adding a small amount of EG on both Pt and Pd electrodes. The onset potential and peak potential of mixture of methanol and EG oxidation are close to or more negative than that of sole methanol and EG oxidation on the Pd electrode. The mixture of methanol and EG is more easily to be electrochemically oxidized and gives a better performance than sole methanol and EG on the Pd electrode. The results show that the mixture of methanol and EG is a promising candidate as fuel in direct alcohol fuel cells. 相似文献
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Hong‐Sik Hwang 《Lipid Technology》2015,27(8):187-189
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Graham J. Hutchings Silvio Carrettin Philip Landon Jennifer K. Edwards Dan Enache David W. Knight Yi-Jin Xu Albert F. Carley 《Topics in Catalysis》2006,38(4):223-230
Selective oxidation is of key importance in the synthesis of chemical intermediates. For many years a number of oxides and
supported metal catalysts have been used. The key questions involved in the design of selective oxidation catalysts are discussed
in the initial part of this paper. One of the most exciting recent developments in the field of selective oxidation has been
the discovery that supported gold catalysts are active. The second part of the paper discusses Au/C catalysts, which are shown
to be particularly versatile for oxidation reactions. Four examples of selective oxidation are described using molecular oxygen
as oxidant: (a) selective oxidation of glycerol to glycerate in the presence of base; (b) the oxidation of cyclohexane to
cyclohexanol and cyclohexanane in the presence of a radical initiator; (c) the oxidation of hydrogen to hydrogen peroxide,
and (d) the oxidation of benzyl alcohol to benzaldehyde under solvent free conditions. In contrast, the Au/C catalysts are
not active for oxidation of carbon monoxide at ambient temperature. These examples demonstrate that there exists a rich potential
for Au/C as a selective oxidation catalyst and that research efforts should now be focussed on selective oxidation using supported
gold catalysts. 相似文献
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对汽车用6061铝合金进行柠檬酸阳极氧化处理。研究发现:铝合金的阳极氧化过程伴随氧化膜的生成和溶解。适当升高氧化温度,有利于增加氧化膜的厚度和硬度。但氧化温度过高,会使得氧化膜的溶解速率加快。铝合金阳极氧化膜呈现典型的多孔结构。40℃下制备的氧化膜表面平整,具有优良的耐蚀性。当氧化温度高于40℃时,氧化膜表面的孔径增大,表面疏松,耐蚀性下降。 相似文献