作為一個新興的熱點學(xué)科，微反應(yīng)器/微通道反應(yīng)器和其代表的連續(xù)化反應(yīng)趨勢受到越來越多的科研機構(gòu)和企業(yè)的關(guān)注。仍然是眾說紛紜，在目前的總體官方，體系介紹的情況下，我們希望以維基百科（Wikipedia）和相關(guān)專業(yè)文獻為藍本，讓微反應(yīng)器更加直觀和體系的呈現(xiàn)在您的面前。以下資料供參詳，能力有限，不足之處歡迎批評指正。

一、介紹 

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.

微反應(yīng)器，微觀結(jié)構(gòu)反應(yīng)器，微通道反應(yīng)器指的是化學(xué)反應(yīng)在橫向尺寸小于1mm范圍內(nèi)即可完成，這種結(jié)構(gòu)的最典型代表就是微通道。微反應(yīng)器是微加工工程領(lǐng)域的學(xué)科，同時同時這個裝置（某種微微換熱器）也伴隨著一些物理反應(yīng)的發(fā)生。這種微反應(yīng)器通常是連續(xù)流體反應(yīng)器（同中斷反應(yīng)器相對）。方面都有優(yōu)勢，完全體現(xiàn)在換熱效率，反應(yīng)速度，轉(zhuǎn)化，安全性，穩(wěn)定性，可監(jiān)測性，現(xiàn)場/按需生產(chǎn)，并且能夠進行更精細化的生產(chǎn)控制。

二、歷史 

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.

氣相微反應(yīng)器已經(jīng)應(yīng)用了很多年，但那些融合了液相的則是直到上世紀九十年代后期才出現(xiàn)。第一代嵌入了高效能換熱器的微反應(yīng)器是由德國卡爾斯魯厄研究中心的中央實驗室制造出來的，使用極限微加工技術(shù)制造出來的微反應(yīng)器初始是制造鈾濃縮分離噴嘴的副產(chǎn)品。伴隨著德國和能源技術(shù)研發(fā)的大量減少，微結(jié)構(gòu)的換熱器唄應(yīng)用一個1997年的早期案例。這種新型的理念，也就是為我們所知的微反應(yīng)技術(shù)或微加工工程，并且伴隨著大量研發(fā)機構(gòu)的應(yīng)用被進一步提升。里我們可以看到在通道刻度90微米深，190微米寬的派萊克斯反應(yīng)器上偶氮反應(yīng)已經(jīng)可以進行。

三、好處 

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:

使用微反應(yīng)器與使用玻璃容器有些不同。這些反應(yīng)堆是有經(jīng)驗的化學(xué)家或反應(yīng)工程師手中的寶貴工具:

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.微反應(yīng)器的典型特征就是換熱效率至少1MW m-3 K-1，高一些的可達到500 MW m-3 K-1。二普通的玻璃儀器只有1 l燒瓶?10 kW m-3 K-1 1。因此，微反應(yīng)器能夠比反應(yīng)釜更高效的散熱，這也使像硝化這種的反應(yīng)反應(yīng)都能夠在高溫狀態(tài)下安全進行。熱區(qū)溫度和高溫持續(xù)時間傳遞散熱而顯著下降。微反應(yīng)器給更佳的動力研究提供了可能，因為反應(yīng)器溫度梯度對反應(yīng)速率的影響比任何傳統(tǒng)反應(yīng)釜都要小。同樣對微反應(yīng)器的制熱和制冷都減少，甚至操作溫度可以低至100℃。伴隨著這種超級換熱器的產(chǎn)生，反應(yīng)溫度可以比傳統(tǒng)反應(yīng)釜高上很多。很多的低溫反應(yīng)，如有機金屬化學(xué)實驗?zāi)軌蛲ㄟ^微反應(yīng)器在-10°C反應(yīng)條件下進行，而不必像實驗室的玻璃裝置那樣溫度需要低至?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.微反應(yīng)器經(jīng)常可以連續(xù)操作，這導(dǎo)致一些間接的中間的后續(xù)合成成為可能，并且避免了一些典型的量產(chǎn)工作耽誤。特別是一些需要采取短暫和秒來的低溫化學(xué)反應(yīng)不再需要存儲數(shù)小時直到反應(yīng)物按計量完成，并且下一步的反應(yīng)有可能已經(jīng)開始。這種快速工作單元避免了寶貴的中間的衰減并且提供了更好的選擇性。

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.連續(xù)操作和混合使得濃度分布和傳統(tǒng)反應(yīng)釜相比有著顯著不同。在反應(yīng)釜體系中，成分A是填滿的而成分B緩慢加入，這就導(dǎo)致B在開始碰到極度過度的A。而在微反應(yīng)器中，A和B的混合幾乎在瞬間完成，這樣B就不會暴露在大量的A中。這也許是這套反應(yīng)設(shè)置的優(yōu)勢或劣勢，而關(guān)注到這種濃度分布的不同狀態(tài)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]雖然一臺桌面上的微反應(yīng)器只可以做小量的化學(xué)合成，但要放大到工業(yè)需求的數(shù)量只是疊加大量的微反應(yīng)器就足夠了。而與之相對的，我們見過了太多的在反應(yīng)釜中反應(yīng)出色但到了工廠合并生產(chǎn)卻失敗的案例。

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.微反應(yīng)器內(nèi)部的材料密封通常要比傳統(tǒng)反應(yīng)釜來的簡單。這導(dǎo)致反應(yīng)效率的增長伴隨著溫度的上升而提升，甚至可以超過溶劑的沸點。這種典型的阿倫尼烏斯行為在微反應(yīng)器中的更容易實現(xiàn)同樣是其核心優(yōu)勢。壓力也許同樣在這種流體狀態(tài)下反應(yīng)氣體的消解變成了可能。

四、問題 

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.

盡管反應(yīng)器是為了處理顆粒物的，但微反應(yīng)器一般情況下很難處理好固體顆粒，經(jīng)常堵塞。雖然相對傳統(tǒng)反應(yīng)釜是一個不錯的替代，但是替代問題已經(jīng)成為了很多研究人員選擇微最后，一種稱為氣流式微反應(yīng)器可以有效的解決顆粒物插入的問題。氣體的參與同樣可能改變反應(yīng)物的保留時間，因為反應(yīng)過程中其體積是不變的。這種現(xiàn)象平均值可能通過壓力的應(yīng)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 ?m may go unnoticed in conventional vessels. As typical inner dimensions of channels are inthe same order of magnitude, characteristics may be altered significantly.

機械已經(jīng)很有可能造成脈動流，而這會產(chǎn)生不良影響。人們已經(jīng)逐漸減少的經(jīng)歷來研發(fā)低脈動流的泵。一種連續(xù)流解決方案就是電滲流。某種的，在微反中表現(xiàn)很好的的一些反應(yīng)在傳統(tǒng)釜中穿透碰到很多問題，特別是進行放大時。通常情況下高體積比和均勻的保留時間很難被輕易放大。但在微反應(yīng)器的管道中這種同樣量級的管道變化，則有可能使某些特征明顯變化。

五、T型反應(yīng)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'.

微反應(yīng)器的最簡單的結(jié)構(gòu)樣式就是T字形。一個板子上的T字的形狀伴隨著40微米的深度和100微米的寬度：通過在一個密封板的雕刻槽頂部進行密封從而將雕刻路線變成了管道。在蓋板上有三個孔用于校準T字型的頂部左端、頂部右端和底部，這樣流體就可以加入或者消除。溶液A從T字形的左端泵進入，溶液B從右端泵進入，如果泵的進料速率相同，這種反應(yīng)成分會在T字型的垂直部分頂部相遇并且隨著兩種液體在T字管道內(nèi)向下，其開始混合而且反應(yīng)。在T字型的基部我們看到兩種液體變成一種。

六、應(yīng)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]

微反應(yīng)器相比現(xiàn)有的釜式技術(shù)在合成材料中更加的高效。這種優(yōu)勢基礎(chǔ)源于傳質(zhì)、熱力學(xué)和高比表面積，同樣在處理不穩(wěn)定中間體中有著工程優(yōu)勢。微反應(yīng)器被應(yīng)用于同光化學(xué)、電合成、多成分反應(yīng)以及縮聚反應(yīng)（比如丙烯酸丁酯的縮聚）。其能夠參與液液反應(yīng)體系，同樣可以應(yīng)用于固液反應(yīng)體系，例如在其管道閉上涂油一種異構(gòu)催化劑。合成同樣和跟產(chǎn)物的純化有關(guān)。通過在合成和純化醛固酮和化學(xué)氣相沉積反應(yīng)的極活性金屬化合物提高反應(yīng)操作的安全性以及產(chǎn)物的高純度，微反應(yīng)器展現(xiàn)了其綠色連續(xù)流化學(xué)的原則。在微反應(yīng)器的研究中縮合反應(yīng)借助著管道上的沸石催化劑而進行，同樣其也出去了在反應(yīng)中生成的水。這種反應(yīng)同樣發(fā)生在被聚合物刷覆蓋的微反應(yīng)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]

這種微反應(yīng)在另一項研究中同樣被印證：一種附著了鈀催化劑的聚丙烯酰胺網(wǎng)狀結(jié)構(gòu)和一種三芳基膦結(jié)構(gòu)通過界面縮合反應(yīng)：丙烷的燃燒證明了即便在300度的低溫下，一個填滿了涂有鉬催化劑的氧化鋁微通道仍然可以按程序反應(yīng)。

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.

酶的固載正在更綠色、更持續(xù)的化學(xué)轉(zhuǎn)變過程中使用的越來越多。微反應(yīng)器通常用于ε--己內(nèi)酯聚己內(nèi)酯的酶催化開環(huán)縮聚研究中。一種由 Bhangale研發(fā)的新型微通道設(shè)計是的異相反應(yīng)能夠在高溫有機相狀態(tài)下連續(xù)反應(yīng)。與反應(yīng)釜相比微反應(yīng)器使得反應(yīng)更快速聚合分子量更大。這證實了相似的基于平臺的微反應(yīng)器能夠應(yīng)用于其他的酶反應(yīng)體系中。例如，高通量篩選的新酶和在連續(xù)流狀態(tài)下的精確控制更容易被選擇。這也是第一例被報道的證實酶催化劑在固載反應(yīng)可以在連續(xù)狀態(tài)下進行。

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.

微反應(yīng)器使得實驗在一個相比于傳統(tǒng)反應(yīng)釜低規(guī)模而且高速率情形下完成，而且不需要收集齊物理實驗產(chǎn)物。這種好處主要是在低生產(chǎn)規(guī)模下結(jié)論和傳感器技術(shù)的集成使得反應(yīng)能夠被理解的更加完善。這種合成、分離和分析能力的集成在微流體狀態(tài)之外實現(xiàn)是不現(xiàn)實的。

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.

荷蘭奈美恩大學(xué)和特溫特大學(xué)的研究員研發(fā)了一種微流體狀態(tài)下的高分辨力核磁流體傳感器，這使得反應(yīng)模擬可以時時進行。這種組赫茲分辨率和痕量樣本已經(jīng)證明是流動化學(xué)非常重要的一個工具。紅外光譜梅特勒·托萊多和光譜儀器部為監(jiān)測提供專用設(shè)備，還有衰減全反射光譜(ATR譜)在微反應(yīng)器反應(yīng)中也會用到。前一種設(shè)備用于表征反應(yīng)監(jiān)測，后面的一種已經(jīng)成功的應(yīng)用于反應(yīng)監(jiān)測和確定反應(yīng)器的分散特性。

八、學(xué)術(shù)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.

微反應(yīng)器即更通用的微反應(yīng)工程，是全球范圍內(nèi)學(xué)術(shù)機構(gòu)的科研學(xué)科。其中之一的代表組織就是IMRET，國際微反應(yīng)技術(shù)協(xié)會。微反應(yīng)器和微反應(yīng)工程模塊同樣成為了其他會議組織的特色單元，比如美國化學(xué)工程師學(xué)會年會，或者化學(xué)反應(yīng)工程國際研討會。相關(guān)探索同樣在全世界其他很多組織中展開。在美國麻省理工學(xué)院，伊利諾斯大學(xué)，俄勒岡州立大學(xué)，加利福尼亞大學(xué)，加州伯克利；瑞士洛桑EPFL，在荷蘭埃因霍溫大學(xué)，奈美恩大學(xué)，荷蘭LIPHT；發(fā)過斯特拉斯堡大學(xué)和里昂大學(xué)。

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:

根據(jù)重點應(yīng)用，目前市場上已經(jīng)擁有了數(shù)量眾多的硬件供應(yīng)商和商業(yè)機構(gòu)來推動服務(wù)市場的發(fā)展。在技術(shù)細分市場的觀點之一就是，提供市場代理的目標(biāo)所需要的市場清算體系。

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).

準備運行（土耳其）系統(tǒng)唄應(yīng)用于那些應(yīng)用于有利于環(huán)境標(biāo)準的新化學(xué)合成計劃，通過調(diào)查發(fā)現(xiàn)其每天可提升大約10-100個實驗每天和反應(yīng)分體系。

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