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    目前为止,关于微通道反应器讲的最全面的文章(内容源自wiki)

    作为一个新兴的热点学科,微反应器/微通道反应器和其代表的连续化反应趋势受到越来越多的科研机构和企业的关注。仍然是众说纷纭,在目前的总体官方,体系介绍的情况下,我们希望以维基百科(Wikipedia)和相关专业文献为蓝本,让微反应器更加直观和体系的呈现在您的面前。以下资料供参详,能力有限,不足之处欢迎批评指正

    微反应器

    一、介绍 

    A microreactor or microstructured reactor or microchannel reactor is a device in which chemical reactions take place in a confinement with typical lateral dimensions below 1 mm; the most typical form of such confinement are microchannels.[1] Microreactors are studied in the field of micro process engineering, together with other devices (such as micro heat exchangers) in which physical processes occur. The microreactor is usually a continuous flow reactor[2][3] (contrast with/to a batch reactor). Microreactors offer many advantages over conventional scale reactors, including vast improvements in energy efficiency, reaction speed and yield, safety, reliability, scalability, on-site/on-demand production, and a much finer degree of process control.

    微反应器,微观结构反应器,微通道反应器指的是化学反应在横向尺寸小于1mm范围内即可完成,这种结构的最典型代表就是微通道。微反应器是微加工工程领域的学科,同时同时这个装置(某种微微换热器)也伴随着一些物理反应的发生。这种微反应器通常是连续流体反应器(同中断反应器相对)。方面都有优势,完全体现在换热效率,反应速度,转化,安全性,稳定性,可监测性,现场/按需生产,并且能够进行更精细化的生产控制。

    二、历史 

    Gas-phase microreactors have a long history but those involving liquids started to appear in the late 1990s.[1] One of the first microreactors with embedded high performance heat exchangers were made in the early 1990s by the Central Experimentation Department (Hauptabteilung Versuchstechnik, HVT) of Forschungszentrum Karlsruhe[4] in Germany, using mechanical micromachining techniques that were a spinoff from the manufacture of separation nozzles for uraniumenrichment.[4] As research on nuclear technology was drastically reduced in Germany, microstructured heat exchangers were investigated for their application in handling highly exothermic and dangerous chemical reactions. This new concept, known by names as microreaction technology or micro process engineering, was further developed by various research institutions. An early example from 1997 involved that of azo couplings in a pyrex reactor with channel dimensions 90 micrometres deep and 190 micrometres wide.

    气相微反应器已经应用了很多年,但那些融合了液相的则是直到上世纪九十年代后期才出现。第一代嵌入了高效能换热器的微反应器是由德国卡尔斯鲁厄研究中心的中央实验室制造出来的,使用极限微加工技术制造出来的微反应器初始是制造铀浓缩分离喷嘴的副产品。伴随着德国和能源技术研发的大量减少,微结构的换热器呗应用一个1997年的早期案例。这种新型的理念,也就是为我们所知的微反应技术或微加工工程,并且伴随着大量研发机构的应用被进一步提升。里我们可以看到在通道刻度90微米深,190微米宽的派莱克斯反应器上偶氮反应已经可以进行。

    三、好处 

    Using microreactors is somewhat different from using a glass vessel. These reactors may be a valuable tool in the hands of an experienced chemist or reaction engineer:

    使用微反应器与使用玻璃容器有些不同。这些反应堆是有经验的化学家或反应工程师手中的宝贵工具:

    1. Microreactors typically have heat exchange coefficients of at least 1 megawatt per cubic meter per kelvin, up to 500 MW m?3 K?1 vs. a few kilowatts in conventional glassware (1 l flask ~10 kW m?3 K?1). Thus, microreactors can remove heat much more efficiently than vessels and even critical reactions such as nitrations can be performed safely at high temperatures.[5] Hot spot temperatures as well as the duration of high temperature exposition due to exothermicity decreases remarkably. Thus, microreactors may allow better kinetic investigations, because local temperature gradients affecting reaction rates are much smaller than in any batch vessel. Heating and cooling a microreactor is also much quicker and operating temperatures can be as low as ?100 °C. As a result of the superior heat transfer, reaction temperatures may be much higher than in conventional batch-reactors. Many low temperature reactions as organo-metal chemistry can be performed in microreactors at temperatures of ?10 °C rather than ?50 °C to ?78 °C as in laboratory glassware equipment.

    1.反应器的典型特征就是换热效率至少1MW m-3 K-1,高一些的可达到500 MW m-3 K-1。二普通的玻璃仪器只有1 l烧瓶?10 kW m-3 K-1 1。因此,微反应器能够比反应釜更高效的散热,这也使像硝化这种的反应反应都能够在高温状态下安全进行。热区温度和高温持续时间传递散热而显着下降。微反应器给更佳的动力研究提供了可能,因为反应器温度梯度对反应速率的影响比任何传统反应釜都要小。同样对微反应器的制热和制冷都减少,甚至操作温度可以低至100℃。伴随着这种超级换热器的产生,反应温度可以比传统反应釜高上很多。很多的低温反应,如有机金属化学实验能够通过微反应器在-10°C反应条件下进行,而不必像实验室的玻璃装置那样温度需要低至?50°C到?78°C。

    2.Microreactors are normally operated continuously. This allows the subsequent processing of unstable intermediates and avoids typical batch workup delays. Especially low temperature chemistry with reaction times in the millisecond to second range are no longer stored for hours until dosing of reagents is finished and the next reaction step may be performed. This rapid work up avoids decay of precious intermediates and often allows better selectivities.[6]

    2.微反应器经常可以连续操作,这导致一些间接的中间的后续合成成为可能,并且避免了一些典型的量产工作耽误。特别是一些需要采取短暂和秒来的低温化学反应不再需要存储数小时直到反应物按计量完成,并且下一步的反应有可能已经开始。这种快速工作单元避免了宝贵的中间的衰减并且提供了更好的选择性。

    3.Microreactors are normally operated continuously. This allows the subsequent processing of unstable intermediates and avoids typical batch workup delays. Especially low temperature chemistry with reaction times in the millisecond to second range are no longer stored for hours until dosing of reagents is finished and the next reaction step may be performed. This rapid work up avoids decay of precious intermediates and often allows better selectivities.[6]

    3.连续操作和混合使得浓度分布和传统反应釜相比有着显著不同。在反应釜体系中,成分A是填满的而成分B缓慢加入,这就导致B在开始碰到极度过度的A。而在微反应器中,A和B的混合几乎在瞬间完成,这样B就不会暴露在大量的A中。这也许是这套反应设置的优势或劣势,而关注到这种浓度分布的不同状态是非常重要的。

    4.Although a bench-top microreactor can synthesize chemicals only in small quantities, scale-up to industrial volumes is simply a process of multiplying the number of microchannels. In contrast, batch processes too often perform well on R&D bench-top level but fail at batch pilot plant level.[7]

    4.[7]虽然一台桌面上的微反应器只可以做小量的化学合成,但要放大到工业需求的数量只是叠加大量的微反应器就足够了。而与之相对的,我们见过了太多的在反应釜中反应出色但到了工厂合并生产却失败的案例。

    5.Pressurisation of materials within microreactors (and associated components) is generally easier than with traditional batch reactors. This allows reactions to be increased in rate by raising the temperature beyond the boiling point of the solvent. This, although typical Arrhenius behaviour, is more easily facilitated in microreactors and should be considered a key advantage. Pressurisation may also allow dissolution of reactant gasses within the flow stream.

    5.微反应器内部的材料密封通常要比传统反应釜来的简单。这导致反应效率的增长伴随着温度的上升而提升,甚至可以超过溶剂的沸点。这种典型的阿伦尼乌斯行为在微反应器中的更容易实现同样是其核心优势。压力也许同样在这种流体状态下反应气体的消解变成了可能。

    四、问题 

    Although there have been reactors made for handling particles, microreactors generally do not tolerate particulates well, often clogging.Clogging has been identified by a number of researchers as the biggest hurdle for microreactors[8]being widely accepted as a beneficial alternative to batch reactors.So far, the so-called microjetreactor   is free of clogging by precipitating products. Gas evolved may also shorten the residence time of reagents as volume is not constant during the reaction. This may be prevented by application of pressure.

    尽管反应器是为了处理颗粒物的,但微反应器一般情况下很难处理好固体颗粒,经常堵塞。虽然相对传统反应釜是一个不错的替代,但是替代问题已经成为了很多研究人员选择微最后,一种称为气流式微反应器可以有效的解决颗粒物插入的问题。气体的参与同样可能改变反应物的保留时间,因为反应过程中其体积是不变的。这种现象平均值可能通过压力的应用而被阻止。

    Mechanical pumping may generate a pulsating flow which can be disadvantageous. Much work has been devoted to development of pumps with low pulsation.A continuous flow solution is electroosmotic flow(EOF).Typically, reactions performing very well in a microreactor encounter many problems in vessels, especially when scaling up. Often, the high area to volume ratio and the uniform residence time cannot easily be scaled.Corrosion imposes a bigger issue in microreactors because area to volume ratio is high. Degradation of few μm may go unnoticed in conventional vessels. As typical inner dimensions of channels are inthe same order of magnitude, characteristics may be altered significantly.

    机械已经很有可能造成脉动流,而这会产生不良影响。人们已经逐渐减少的经历来研发低脉动流的。一种连续流解决方案就是电渗流。某种的,在微反中表现很好的的一些反应在传统釜中穿透碰到很多问题,特别是进行放大时。通常情况下高体积比和均匀的保留时间很难被轻易放大。但在微反应器的管道中这种同样量级的管道变化,则有可能使某些特征明显变化。

    五、T型反应堆

    One of the simplest forms of a microreactoris a 'T' reactor. A 'T' shape is etched into a plate with a depth that may be 40 micrometres and a width of 100 micrometres: the etched path  is turned into a tube by sealing a flat plate  over the top of the etched groove. The cover plate has  three holes that  align to the  top-left, top-right, and bottom of  the 'T' so  that fluids can  be added and  removed. A solution of reagent 'A' is pumped into the top left of the 'T' and solution 'B' is pumped into the top right of the 'T'. If the pumping rate is the same, the components meet at the top of the vertical part of the 'T' and begin to mix and react as they go down the trunk of the 'T'. A solution of product is removed at the base of the 'T'.

    微反应器的最简单的结构样式就是T字形。一个板子上的T字的形状伴随着40微米的深度和100微米的宽度:通过在一个密封板的雕刻槽顶部进行密封从而将雕刻路线变成了管道。在盖板上有三个孔用于校准T字型的顶部左端、顶部右端和底部,这样流体就可以加入或者消除。溶液A从T字形的左端泵进入,溶液B从右端泵进入,如果泵的进料速率相同,这种反应成分会在T字型的垂直部分顶部相遇并且随着两种液体在T字管道内向下,其开始混合而且反应。在T字型的基部我们看到两种液体变成一种

    六、应用 

    1.Microreactors can be used to synthesise material more effectively than current batch techniques allow. The benefits here are primarily enabled by the mass transfer, thermodynamics, and high surface area to volume ratio environment as well as engineering advantages in handling unstable intermediates. Microreactors are applied in combination with photo chemistry, electrosynthesis, multicomponent reactions and polymerization (for example that of butyl acrylate). It can involve liquid-liquid systems but also  solid-liquid systems with for example the channel walls coated with a heterogeneous catalyst. Synthesis is also combined with online purification oftheproduct.[1]  Following   Green  Chemistry  principles,  microreactors  can   be  used   to synthesize and purify extremely reactive Organometallic Compounds for ALD  and CVD[9][10] applications, with improved safety in operations and higher purity products. In microreactor studies aKnoevenagel condensation[11] was performed with the channel coated with a zeolite catalyst layer which also serves  to remove water generated in the reaction.  The same  reaction  was  performed in  a  microreactor  covered  by polymer brushes.[12]

    微反应器相比现有的釜式技术在合成材料中更加的高效。这种优势基础源于传质、热力学和高比表面积,同样在处理不稳定中间体中有着工程优势。微反应器被应用于同光化学、电合成、多成分反应以及缩聚反应(比如丙烯酸丁酯的缩聚)。其能够参与液液反应体系,同样可以应用于固液反应体系,例如在其管道闭上涂油一种异构催化剂。合成同样和跟产物的纯化有关。通过在合成和纯化醛固酮和化学气相沉积反应的极活性金属化合物提高反应操作的安全性以及产物的高纯度,微反应器展现了其绿色连续流化学的原则。在微反应器的研究中缩合反应借助着管道上的沸石催化剂而进行,同样其也出去了在反应中生成的水。这种反应同样发生在被聚合物刷覆盖的微反应器中。

    2.A Suzuki reaction was examined in another study[13] with a palladium catalyst confinedin a  polymer network of polyacrylamide and  a triarylphosphine formed by  interfacialpolymerization:The combustion of propane was demonstrated to occur at temperatures as low as 300 °C  in a microchannel setup filled up with an aluminum oxidelattice coated with aplatinum / molybdenumcatalyst:[14]

    这种微反应在另一项研究中同样被印证:一种附着了钯催化剂的聚丙烯酰胺网状结构和一种三芳基膦结构通过界面缩合反应:丙烷的燃烧证明了即便在300度的低温下,一个填满了涂有钼催化剂的氧化铝微通道仍然可以按程序反应。

    3.Enzymes  immobilized on solid  supports are increasingly used  for greener, more sustainable chemical transformation processes.Microreactors are  used to  study  enzyme-catalyzed ring-opening  polymerization of  ε-caprolactone to  polycaprolactone. A  novel microreactordesign developed by Bhangale et al.[15][16] enabled to perform hetero geneous reactions in continuous mode, in organic media, and at  elevated temperatures. Using microreactors, enabled  faster polymerization and higher molecular mass  compared to using batch reactors. It is evident that similar microreactor based platforms can readily be extended to other enzyme-based systems,for example, high-throughput screening of new  enzymes and to precision  measurements of new processes where continuous flow mode  is  preferred. This  is  the  first reported  demonstration of  a  solid  supported enzyme-catalyzed  polymerization reaction  in continuous mode.

    酶的固载正在更绿色、更持续的化学转变过程中使用的越来越多。微反应器通常用于ε--己内酯聚己内酯的酶催化开环缩聚研究中。一种由 Bhangale研发的新型微通道设计是的异相反应能够在高温有机相状态下连续反应。与反应釜相比微反应器使得反应更快速聚合分子量更大。这证实了相似的基于平台的微反应器能够应用于其他的酶反应体系中。例如,高通量筛选的新酶和在连续流状态下的精确控制更容易被选择。这也是第一例被报道的证实酶催化剂在固载反应可以在连续状态下进行。

    七、分析 

    Microreactors can also  enable experiments to  be performed at  a far  lower scale and  far higher experimental rates  than currently possible in batch production, while not collecting the physical experimental output. The benefits here are primarily derived from the low operating scale, and the integration of the required sensor technologies to allow high quality understanding of an experiment. The integration of the required synthesis, purification and analytical capabilities is impractical when operating outside of a microfluidic context.

    微反应器使得实验在一个相比于传统反应釜低规模而且高速率情形下完成,而且不需要收集齐物理实验产物。这种好处主要是在低生产规模下结论和传感器技术的集成使得反应能够被理解的更加完善。这种合成、分离和分析能力的集成在微流体状态之外实现是不现实的。

    Researchers at  the Radboud  University Nijmegen and  Twente University,  the  Netherlands, have developed a  microfluidic high-resolution NMR flow probe. They have shown a model reaction being followed in real-time. The combination of the uncompromised (sub-Hz) resolution and a low sample volume can prove to be a valuable tool for flow chemistry.[17] Infrared spectroscopy Mettler Toledo and  Bruker Optics offer dedicated  equipment for monitoring, with  attenuated total reflectance spectrometry (ATR spectrometry)  in  microreaction  setups. The   former  has  been  demonstrated  for  reaction  monitoring.[18]  The  latter  has   been successfully used for reaction monitoring[19] and determining dispersion characteristics[20] of a microreactor.

    荷兰奈美恩大学和特温特大学的研究员研发了一种微流体状态下的高分辨力核磁流体传感器,这使得反应模拟可以时时进行。这种组赫兹分辨率和痕量样本已经证明是流动化学非常重要的一个工具。红外光谱梅特勒·托莱多和光谱仪器部为监测提供专用设备,还有衰减全反射光谱(ATR谱)在微反应器反应中也会用到。前一种设备用于表征反应监测,后面的一种已经成功的应用于反应监测和确定反应器的分散特性。

    八、学术研究

    Microreactors, and  more  generally, micro  process  engineering,  are  the subject  of  worldwide  academic research.  A  prominent recurring conference  is  IMRET,  the International  Conference  on  Microreaction Technology.  Microreactors  and  micro process engineering have also been featured in dedicated sessions of other conferences,such as the Annual Meeting of the American Institute of Chemical Engineers (AIChE), or the International Symposia on Chemical Reaction Engineering (ISCRE).  Research is now also

    conducted  at  various  academic  institutions  around  the   world,  e.g.  at  the  Massachusetts  Institute  of   Technology  (MIT)  in Cambridge/MA, University of Illinois  Urbana-Champaign, Oregon  State University in  Corvallis/OR, at University of  California,

    Berkeley in Berkeley/CA  in the  United States, at the  EPFL in Lausanne,  Switzerland, at  Eindhoven University of Technology in Eindhoven, at  Radboud  University Nijmegen  in Nijmegen,  Netherlands and  at  the  LIPHT [1]  of  Université de  Strasbourg  in Strasbourg and [2] of the University of Lyon, CPE Lyon, France.

    微反应器即更通用的微反应工程,是全球范围内学术机构的科研学科。其中之一的代表组织就是IMRET,国际微反应技术协会。微反应器和微反应工程模块同样成为了其他会议组织的特色单元,比如美国化学工程师学会年会,或者化学反应工程国际研讨会。相关探索同样在全世界其他很多组织中展开。在美国麻省理工学院,伊利诺斯大学,俄勒冈州立大学,加利福尼亚大学,加州伯克利;瑞士洛桑EPFL,在荷兰埃因霍温大学,奈美恩大学,荷兰LIPHT;发过斯特拉斯堡大学和里昂大学。

    Depending on  the  application focus,  there are  various  hardware suppliers  and commercial  development entities  to service  the evolving market. One view to technically segment market, offering and market clearing stems from the scientific and technological objective of market agents:

    根据重点应用,目前市场上已经拥有了数量众多的硬件供应商和商业机构来推动服务市场的发展。在技术细分市场的观点之一就是,提供市场代理的目标所需要的市场清算体系。

    a. Ready to Run (turnkey) systems are being used where the application environment stands to benefit from new chemical synthesis schemes, enhanced investigational throughput of up to approximately 10 - 100 experiments per day (depends on reaction time) and reaction subsystem, and actual synthesis conduct at scales ranging from 10 milligrams per experiment to triple digit tons per year (continuous operation of a reactor battery).

    准备运行(土耳其)系统呗应用于那些应用于有利于环境标准的新化学合成计划,通过调查发现其每天可提升大约10-100个实验每天和反应分体系。

    免责声明:文章来源《 微通道反应器》-微信公众号  原创:clay  以传播知识、有益学习和研究为宗旨。 转载仅供参考学习及传递有用信息,版权归原作者所有,如侵犯权益,请联系删除。


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