Three-channel microreactor

Single channel microreactor Three channel microreactor... 

The performance of a single-channel and a numbered-up three-channel microreactor was similar [273]. Some differences were found that probably originate more from fluctuations in the hydrodynamics than from the numbering up. 

The directed fluorination reaction of diethyl malonate can be performed in a three-channel microreactor (Scheme 8.1) [8]. The synthesis offluoro- and difluoromalonate esters by the fluorination of Meldrum s acid is readily achieved in a microflow reactor without the use of added catalysts or malonate salts as substrates that are required in a conventional macrobatch reaction. 

The synthesis of the organic sulfur pentafluo rides has also been studied in the case of m- and p-nitrophenylsulfur pentafluoride. m-Nitrophenylsulfur pentafluoride can be synthesized directly from di(m-nitrophenyl) disulfide in one step by using a singlechannel microreactor (75% yield) and a three-channel microreactor (56% yield) (Scheme 8.3). 

The fluorination reaction of p-nitrotoluene in formic acid can be carried out using 10% F2 in N2 in a three-channel microreactor to give fluorinated product in 78% yield (Table 8.3) [4,5,6]. Fluorination of 4-nitrotoluene is carried out in mixtures of acetonitrile and formic acid (3 2 v/v) because the formation of fluorinated p-nitrotoluene leads to blockage of the microchannel due to the low solubility of the substrate in formic acid. 

The fluorination reaction of o,p-dinitrotoluene in formic acid can also be carried out in a continuous three-channel microreactor using 10% F2 in N2 to give the corresponding fluorinated product in 70% conversion yield (Scheme 8.5). 

Single-/three-channel thin-film microreactor [44, 45] The reactor, which was initially made as a single-mi-crochaimel version and later as numbered-up three-microchannel version, was developed specially for fluorination reactions... 

After the initial manufacture of a single-microchannel version [63], a numbered up (scale-out) three-channel microreactor followed later [64]. 

A catalyst can be loaded on the surface of the channel wall of a glass microchip reactor. Such a microreactor has been used for gas/liquid/solid three-phase catalytic reactions, as shown in Figure 7.27. " ... 

Fig. 12.20 O2 conversion data versus temperature for the oxidation of CH4 for three microreactor channels. Open-loop temperature control was used in this experiment with each heater set to the same heater voltage. The temperature used for the plot is the average of the measured RTD temperatures. These results come from one AIMS experiment with three...

Fig. I a The FIA IV-I and II integrated biosensor systems I concentrated sample solution, 2 diluted sample solution, 3 reagent solution, 4 eightK hannel distribution valve, 5 peristaltic pump, 6 microreactors, 7 eightway injection valve, 8 temperature chamber control, 9 colorimeter, 10 micro computer, II waste, 12 coil, 13 peristaltic pump for sample dilution, 14 phosphate buffer, b The SIA integrated biosensor system I, 2 and 3 phosphate buffer solution 4 ethanol diluted sample 5 reagent solution 6 waste 7 1,000-pl micro-buiette 8 500-pl micro-burette P peristaltic pump 10 two three-way valves II six-channel distribution valve 12 colorimeter, 13 serpentine 14 AOD-immobilized microieactor 15 HRP-immobilized microreactor, 16 computer 17 Interface RS-232/RS-485...

So far, we have considered catalytic materials that conform to the side walls of a microreactor. A downside to a functionalized coating at a channel wall is the limited catalytic surface area that can be provided. As an alternative, thin-film technology can be used for depositing catalytic materials on more complex three-dimensional surfaces inside microchannels [49]. Impregnation methods can also be used on porous silicon surfaces [50]. The mass transfer rates described for such structures are sufficient for all but the fastest heterogeneous reactions. 

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