Microchip-based synthesis and analysis: Control of multicomponent reaction products and intermediates

Mitchell, Michael C.; Spikmans, Val; Mello, Andrew J. de

doi:10.1039/b007397k

Cited by 79 publications

(63 citation statements)

References 25 publications

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“…4,20 In this paper, we introduce a new concept of a dynamic micromixer (Fig. 1), which combines the concepts of parallel [14][15][16]26 multi-lamination12 and hydrodynamic focusing.18 , 27 This dynamic mixer composed of 200 µm wide and 80 µm high microchannels was fabricated from poly-methylmethacrylate (PMMA) materials 28 or polydimethylsiloxane (PDMS)8 (see ESI † ). There are three geometrically defined sections in the device, including: (i) a hydrodynamic focusing region where reactant and isolation streams are introduced into the device through the nine inletting microchannels, (ii) a linear microchannel for controlled mixing, and (iii) a triple-branched junction for collecting the resulting reaction mixtures and bypassing the sheath streams.…”

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A dynamic micromixer for arbitrary control of disguised chemical selectivity

et al. 2008

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A new type of dynamic micromixer combining the concepts of parallel multi-lamination and hydrodynamic focusing was developed for arbitrary control of disguised chemical selectivity.Microreactors are microscopic reaction settings that exhibit unique properties versus traditional macroscopic environments: advantages of microreactors include reduced reagent consumption, high surface-area-to-volume ratios and improved control over mass and heat transfer. [1][2][3][4][5][6][7][8] In addition, fluidic physical phenomena in the microreactors are dramatically different from those observed in the macroscopic reaction apparatuses. [9][10][11] For instance, the inertial effect in the microfluidic environment is negligible (due to a low value of Reynolds number, Re), and thus fluid transport is dictated by fluid viscosity, leading to laminar flow in microchannels. A microfluidics-based reactor is known to be a turbulence-free system, in which diffusion-driven mixing is relatively slow. As a result, one of the most challenging issues in the field of microreactor design is to facilitate mixing in stand-alone devices. Over the past decades enormous efforts have been devoted to develop micromixers (one type of microreactor) that can be categorized into either active or passive ones. 12 Unlike active micromixers, passive ones13 do not require external power, are often composed of robust channel geometry or microstructures, and are developed upon straightforward concepts of increasing contact surfaces and/or shortening the distance for diffusion among different streams. For example, devices based on parallel14 -16 multi-lamination 12 have been developed to achieve efficient mixing. † Mixing may impact reaction outcomes. 17,18 A good example is the diazo coupling reaction 19 between 4-sulfono-benzenediazonium (1) and 1-naphthol (2) under alkaline conditions at room temperature. This reaction is known as a fast competitive consecutive reaction 20 (Scheme 1), where the selectivity between the two major reaction products (i.e., monosubstituted product 3 and disubstituted product 4) is not only determined by intrinsic reaction kinetics 21 (k 1 = 1.2 × 10 7 M −1 s −1 and k 2 = 2 × 10 3 M −1 s −1 ) but also affected by the mixing rates. When reactants 1 and 2 are mixed in a macroscopic setting, the reaction solution is first fragmented by stir-induced turbulence. No matter what mixing approach (e.g., hand mixing or mechanical stirring) is applied, in the best case scenario, the mean radii of the fragmentized solutions are approximately in the range of 100 to 1000 µm, 22,23 leading to a mixing time ranging from a millisecond to seconds. Consequently, the fast reaction between the 1 and 2 happens prior to complete homogeneous mixing to give a complicated reaction mixture containing reactant 2 and products 3 and 4. This phenomenon is known as the disguised chemical selectivity. 20,24,25 In order to avoid the undesired disguised chemical selectivity, micromixers exhibiting fast mixing rates have been developed. 4,20 In this paper,...

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A dynamic micromixer for arbitrary control of disguised chemical selectivity

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“…Most synthesis reactions that have been performed within droplets are single-step synthesis reactions [61][62][63][64][65]. One major issue in complex synthesis is that multiple reaction steps are involved.…”

Section: Droplet-based Chemical Synthesismentioning

confidence: 99%

Droplet microfluidics: A tool for biology, chemistry and nanotechnology

Mashaghi

Abbaspourrad

Weitz

et al. 2016

TrAC Trends in Analytical Chemistry

309

188

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The ability to perform laboratory operations on small scales using miniaturized devices provides numerous benefits, including reduced quantities of reagents and waste as well as increased portability and controllability of assays. These operations can involve reaction components in the solution phase and as a result, their miniaturization can be accomplished through microfluidic approaches. One such approach, droplet microfluidics, provides a high-throughput platform for a wide range of assays and approaches in chemistry, biology and nanotechnology. We highlight recent advances in the application of droplet microfluidics in chipbased technologies, such as single-cell analysis tools, small-scale cell cultures, in-droplet chemical synthesis, high-throughput drug screening, and nanodevice fabrication.

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“…8.1c, d) for testing a variety of chemical reactions (Chambers and Spink 1999;Wiles and Watts 2011); multilamellae systems ( Fig. 8.1e) for reactions, extraction, emulsification (Sprogies et al 2008;Mitchell et al 2001;Suga et al 2003); SAR mixers ( Fig. 8.1f) for organic synthesis (Hessel et al 2005a), extraction Okubo et al 2004) and crystallization (Jung et al 2012).…”

Section: Overview On Micro Mixing Technologymentioning

confidence: 99%

Microfluidics in Planar Microchannels: Synthesis of Chemical Compounds On-Chip

Arima

Watts

Pascali

2014

Lab-on-a-Chip Devices and Micro-Total Analysis Systems

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Microreactors are a wide class of devices that are currently playing a prominent role in several research fields such as biology, medicine, food chemistry, environmental analysis, up to the production of compounds in organic chemistry. Several typologies of microreactors have been produced with tubular or planar shapes, of different materials and designs. In this chapter, an overview of planar microchannel-based microreactors and their application to organic chemistry is given. Initially, after recalling the main theoretical parameters of microfluidics, an introduction of the proposed technology and the main requirements to perform mixing, which is essential to perform chemical synthesis on-chip, is presented. Silicon and glass microreactors, the most common planar systems for organic chemistry, are described with the aim of pointing out the most important parameters to be taken into consideration in the planning of a specific microreactor to be used for mixing, purification or crystallization of chemicals at the microscale. Then, several applications of initially described microreactors to organic chemistry for research applications are given. In the next section, the use of planar microchannel microreactors in the field of radiochemistry is reported. The radiopharmaceutical application is not casual, being a sector in which the microreactor technology is very promising, due to the need of quickly producing small and fresh amounts of products in a controlled environment. Finally, for completeness, other approaches beyond planar microchannels are mentioned: mesoreactors towards industrial level synthesis and micro-vessels for radiochemistry.

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Microchip-based synthesis and analysis: Control of multicomponent reaction products and intermediates

Cited by 79 publications

References 25 publications

A dynamic micromixer for arbitrary control of disguised chemical selectivity

A dynamic micromixer for arbitrary control of disguised chemical selectivity

Droplet microfluidics: A tool for biology, chemistry and nanotechnology

Microfluidics in Planar Microchannels: Synthesis of Chemical Compounds On-Chip

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