共查询到19条相似文献,搜索用时 125 毫秒
1.
2.
3.
以1,10-邻菲啰啉5,6-二酮及苯甲醛(或取代苯甲醛)为原料, 在微波辐射条件下制备了一系列菲并咪唑类衍生物, 考察了温度、 时间以及投料比对微波辅助合成菲并咪唑类衍生物的影响, 并进一步探讨了微波非热效应的影响. 设计正交实验优化了反应条件; 使用SiC管作为反应容器屏蔽微波对反应的影响; 通过元素分析、 核磁共振波谱、 质谱及红外光谱等对化合物进行了表征. 结果表明, 微波辅助反应的最佳反应条件为: 1,10-邻菲啰啉-5,6-二酮与苯甲醛(或取代苯甲醛)的投料比为1: 1.5, 反应温度为100℃, 反应时间为20 min; 并且发现SiC管中反应的产率明显低于石英管反应容器. 与传统制备方法相比, 微波辅助合成方法可在更短时间内快速方便地制得菲并咪唑类衍生物; 反应温度、 反应时间以及投料比对微波辅助合成反应有明显影响; 微波非热效应有助于提高反应产率. 相似文献
4.
5.
6.
7.
8.
微波是一种能量传递方式。与传统电加热相比,微波加热具有加热速度快、热惯性小、选择性加热等特点,因而被视为一种优质的能量来源。微波催化是一种使用微波对反应系统供能,从而推动催化反应进行的化学过程。近年来,许多研究者致力于探索和发展微波催化技术,包括利用微波技术提升化学反应速率、开发具有出色微波吸收能力的催化剂、建立节能环保的微波催化系统等。本文首先介绍了微波的相关理论,讲述了材料对微波的吸收原理;然后从微波催化降解挥发性有机物(Volatile Organic Compounds, VOCs)、微波催化污水处理、微波催化生物质热解和微波催化碳氢化合物转化等方面综述了微波催化在能源环境中的应用;最后对微波催化过程的机理展开了讨论。 相似文献
9.
10.
11.
Significant progress has been achieved in the last years on microwave synthesis of zeolite membranes. In many cases, microwave synthesis has proven to remarkably reduce the synthesis time. In addition, microwave synthesis could also result in different membrane morphology, orientation, composition, and thus the different permeation characteristics as compared with those synthesized by conventional heating. This review attempts to summarize the obtained progress in microwave synthesis of zeolite membranes. Some topics are discussed, including: (1) case study of microwave synthesis of zeolite membranes, e.g. LTA, MFI, AFI, and other types of zeolite membranes; (2) differences between conventional and microwave synthesis; (3) formation mechanism and the so called “specific microwave effect” in the case of microwave synthesis of zeolite membranes; (4) scaling-up of zeolite membrane production by employing microwave heating. The latter three topics are mainly focused on LTA type zeolite membranes. Concluding remarks and future perspective are also suggested in the end. 相似文献
12.
在微波作用下,采用高效催化剂体系,于中等极性非质子溶剂中经卤素交换氟化高效制备了系列含氟芳香醛(酮)类化合物,产品收率53·3%~92·6%,反应时间较常规加热最多可缩短80%以上。采用中等极性反应溶剂,还可突出表现出微波对反应促进的“非热效应”,从而大大拓宽了氟化反应溶剂的选择范围。 相似文献
13.
The conversion of carbon dioxide is vital if we are to avoid the catastrophic consequences that will result from further global temperature rise as a result of burning fossil fuels. Current techniques, such as catalytic conversion and biochemical processes, are each associated with their own drawbacks such as catalyst deactivation and high energy input. Plasma processes are gaining increasing interest as they have the potential to reduce a greater amount of atmospheric environmental pollutants at any one time due to an increased throughput, whilst using a smaller reactor with improved energy efficiency and near-zero emissions. Non-thermal plasma can dissociate stable molecules, such as CO2, at temperatures as low as room temperature. It is this key feature which makes plasma conversion such a promising technology in the conversion and utilisation of CO2. Furthermore, possible products from plasma processes include fuels and chemicals, such as methanol and syngas, which have a high market value; hence potentially making the process feasible on an industrial scale. This paper discusses recent advances in the use of plasma processes for carbon dioxide conversion, along with the future outlook of this technology and the impact these techniques could have on the chemical and energy industries. 相似文献
14.
石墨烯导热研究进展 总被引:1,自引:0,他引:1
石墨烯具有目前已知材料中最高的热导率,在电子器件、信息技术、国防军工等领域具有良好的应用前景。石墨烯导热的理论和实验研究具有重要意义,在最近十年间取得了长足的发展。本文综述了石墨烯本征热导率的研究进展及应用现状。首先介绍应用于石墨烯热导率测量的微纳尺度传热技术,包括拉曼光谱法、悬空热桥法和时域热反射法。然后展示了石墨烯热导率的理论研究成果,并总结了石墨烯本征热导率的影响因素。随后介绍石墨烯在导热材料中的应用,包括高导热石墨烯膜、石墨烯纤维及石墨烯在热界面材料中的应用。最后对石墨烯导热研究的成果进行总结,提出目前石墨烯热传导研究中存在的机遇与挑战,并展望未来可能的发展方向。 相似文献
15.
Despite the great success of Microwave Assisted Organic Synthesis (MAOS) there is still a lack of knowledge about the interaction of the electromagnetic radiation with matter. In consequence, it has been very difficult to rationalize the effect of microwave irradiation in chemistry, to determine the existence of microwave effects (thermal and non‐thermal) and to develop predictive models on the characteristics required for a reaction to be improved under microwaves. This has been a handicap to develop new chemistry under microwave irradiation and the origin of many controversies. This personal account collects some new findings in this field and our work on the use of computational chemistry to develop predictive models and to determine parameters related to thermal and non‐thermal effects, with clear advantages over experimental methods where separation of these effect is almost impossible. 相似文献
16.
微波辅助提取(MAE)研究进展 总被引:37,自引:0,他引:37
在过去的十几年来,微波能已广泛应用于食品加工、农业,林业,轻工业,医疗卫生,橡胶和塑料的固化,陶瓷烧结,提取冶金,有机合成,生物样品水解,微波辅助提取等领域。特别是微波辅助提取技术近年来发展较快,引起化学工作者的极大兴趣。本文初步探讨了微波加热的机理,特点及近十年来微波辅助提取研究和应用的进展,并展望了微波辅助提取的发展前景。 相似文献
17.
18.
Frank Marken Yu-Chen Tsai Andrew J. Saterlay Barry A. Coles Daniel Tibbetts Katherine Holt Christiaan H. Goeting John S. Foord Richard G. Compton 《Journal of Solid State Electrochemistry》2001,5(5):313-318
Microwave activation of electrochemical processes has recently been introduced as a new technique for the enhancement and
control of processes at electrode|solution (electrolyte) interfaces. This methodology is extended to processes at glassy carbon
and boron-doped diamond electrodes. Deposition of both Pb metal and PbO2 from an aqueous solution of Pb2+ (0.1 M HNO3) are affected by microwave radiation. The formation of PbO2 on anodically pre-treated boron-doped diamond is demonstrated to change from kinetically sluggish and poorly defined at room
temperature to nearly diffusion controlled and well defined in the presence of microwave activation. Calibration of the temperature
at the electrode|solution (electrolyte) interface with the Fe3+/2+ (0.1 M HNO3) redox system allows the experimentally observed effects to be identified as predominantly thermal in nature and therefore
consistent with a localized heating effect at the electrode|solution interface. The microwave-activated deposition of PbO2 on boron-doped diamond remains facile in the presence of excess oxidizable organic compounds such as ethylene glycol. An
increase of the current for the electrocatalytic oxidation of ethylene glycol at PbO2/boron-doped diamond electrodes in the presence of microwave radiation is observed. Preliminary results suggest that the electrodissolution
of solid microparticles of PbO2 abrasively attached to the surface of a glassy carbon electrode is also enhanced in the presence of microwave radiation.
Electronic Publication 相似文献
19.
Chuthamat Duangkamol Paratchata Batsomboon Albert E. Stiegman Gregory B. Dudley 《化学:亚洲杂志》2019,14(15):2594-2597
Microwave (MW) heating is more effective than conventional (CONV) heating for promoting a high‐temperature oxidative cycloisomerization reaction that was previously reported as a key step in a total synthesis of the natural product illudinine. The thermal reaction pathway as envisioned is an inverse electron‐demand dehydro‐Diels–Alder reaction with in situ oxidation to generate a substituted isoquinoline, which itself is unstable to the reaction conditions. Observed reaction yields were higher at a measured bulk temperature of 200 °C than at 180 °C or 220 °C; at 24 hours than at earlier or later time points; and when the reaction solution was heated using MW energy as opposed to CONV heating with a metal heat block. Selective MW heating of polar solute aggregates is postulated to explain these observations. 相似文献