Reactor with micro mixer

Reactor 2 [R 2] Steel Multi-plate-stack Reactor with Micro Mixer... 

The performance of the Sonogashira reaction is claimed to be the first example of a homogeneously metal-catalyzed reaction conducted in a micro reactor [120], Since the reaction involves multi-phase postprocessing which is needed for the separation of products and catalysts, continuous recycling technology is of interest for an efficient production process. Micro flow systems with micro mixers are one way to realize such processing. 

Fig. 6 High p,T operation for the radical side-chain bromination of m-nitro toluene in a micro-mixer-reactor setup. The large increase in operational temperature increases conversion at good selectivities, which tend to decline slightly with temperature. The two-fold substituted product, m-nitro toluene benzal bromide, is formed in larger amounts at temperatures above 200°C (IMM, unpublished results)...

The whole set-up for partial oxidation comprises a micro mixer for safe handling of explosive mixtures downstream (flame-arrestor effect), a micro heat exchanger for pre-heating reactant gases, the pressure vessel with the monolith reactor, a double-pipe heat exchanger for product gas cooling and a pneumatic pressure control valve to allow operation at elevated pressure [3]. 

This class is the simplest of all micro reactors and certainly the most convenient one to purchase, but not necessarily one with compromises or reduced fimction. HPLC or other tubing of small internal dimensions is used for performing reactions. There are many proofs in the literature for process intensification by this simple concept. As a micro mixer is missing, mixing either has to be carried out externally by conventional mini-equipment or may not be needed at all. The latter holds for reactions with one reactant only or with a pre-mixed reactant solution, which does not react before entering the tube. 

Reactor 9 [R 9] Chip System with Triangular Interdigital Micro Mixer-Reaction Channel... 

This system is a chip version of three dimensional micro mixer-tube reactor setups [21]. It comprises a triangular interdigital micro mixer with a focusing zone that thins the multi-lamellae and a subsequent reaction channel that is surrounded... 

Figure4.9 Chip system with triangular interdigital micro mixer-reaction channel. First- (top) and second- (bottom) generation reactor designs [22],...

One version of such a reactor concept is the combination of a slit-type in ter digital metal/steel micro mixer (for a detailed description see [R 18]) with a conventional tube. In [37], PTFE tubing was applied (Figure 4.20). 

Reactor 24 [R 24] System with Series of Micro Mixers-Cross-Flow Reactor Modules... 

Reactor type System with series of micro mixers-cross-flow reactor moldules Number of reaction channels 169... 

Reactor 26 [R 26] Chip Micro Reaction System with Parallel Mixer-Reaction Channels... 

Reactor type Chip micro reaction system with parallel mixer-reachon channels Plate thicknesses 2 X 0.2 mm 5 X 0.7 mm 1x1 mm... 

OS 1] [R 20] [P 1] A comparison of the selectivity/conversion behavior of an interdigital micro mixer-tube reactor with that of a mixing tee of about 1.5 mm inner diameter (and thus of larger internal dimensions) was made (Figure 4.39). For all data gathered, the performance of the micro mixer was much better, e.g. about 30% more selectivity at a given conversion [46]. 

Micro reactors show, under certain conditions, low axial flow dispersion reactions with unstable intermediates can be carried out in a fast, stepwise manner on millisecond time-scales. Today s micro mixers mix on a millisecond scale and below [40]. Hence in micro reactors reactions can be carried out in the manner of a quench-flow analysis, used for determination of fast kinetics [93]. 

P 27] Diazotation was performed in batchwise manner [55]. A CPC micro reactor with multi-lamination mixer (lamellae < 100 pm) was embedded in a housing... 

OS 41a] [R 19] ]P 30] A study was undertaken to compare extended (1 h) processing in small vials (2 cm ) with short-time (100 s) continuous micro reactor and mini-batch (10 cm ) operation for 10 different substrates (C4-C8 alcohols) which were reacted with rhodium(I)-tris(m-sulfophenyl)phosphane [111]. The vials were either directly filled with the two phases yielding a bilayered fluid system with small specific interfaces or by interdigital micro mixer action yielding an emulsion with large specific interfaces. 

In contrast to this result, polymer samples taken from processing without a micro mixer displayed a small but significant fraction of high-molecular weight polymer with a mass > 10 [126]. Here, in some cases, heavy precipitation occurred, resulting even in plugging of the static-mixer internals of the tube reactors [125]. 

OS 89] [R 19] [P 69] Using a special reactor configuration with an interdigital micro-mixer array with pre-reactor, subsequent tubing and a quench, a yield of 95% at 0 °C was obtained [127]. The industrial semi-batch process had the same yield at -70 °C. 

Figure 5.28 Schematic of the experimental set-up. Water/ethylene glycol/SDS reservoir (a) high-pressure liquid pumps (b) catalyst/ substrate HPLC injection valve with 200 pi sample loop (c) hydrogen supply, equipped with mass flow controller (d) micro mixer (e) heating jacket (f) tubular glass or quartz reactor (g) back-pressure regulator (h) [64],...

The micro-mixer is supplied continuously with two carrier fluids, either two immiscible liquids or a gas and a liquid. During screening, pulses of the dissolved catalyst to be screened and the substrate are injected simultaneously by a pipetting robot. The pulses are then mixed in a micro-mixer and form short defined reacting segments that move along the tubular reactor. 

M 39] [P 37] Using an azo-type competitive reaction, the selectivities were compared for the P- and V-type micro mixers having straight and oblique fluid injection, respectively [41]. In this way, laminar- and turbulent-flow mixing achieved by vertical interdigital microstructured mixers can be compared. The selectivities of the turbulent V-type mixer are better to some extent as compared with the P-type device however, neither approaches the characteristics of the ideal tubular reactor. The micro devices, however, are better than a conventional jet mixer. 

Flego [1] recommends the use of micro devices for automated measurement and microanalysis of high-throughput in situ characterization of catalyst properties. Murphy et al. [5] stress the importance of the development of new reactor designs. Micro reactors at Dow were described for rapid serial screening of polyolefin catalysts. De Bellefon ete al. used a similar approach in combination with a micro mixer [6], Bergh et al. [7] presented a micro fluidic 256-fold flow reactor manufactured from a silicon wafer for the ethane partial oxidation and propane ammoxidation. 

The authors applied this concept to both gas/liquid (see Figure 3.75) and liquid/ liquid systems (see Figure 3.76). This set-up consisted in the core of a tubular reactor with an interdigital micro mixer as dispersion unit (compare Figure 3.77). The peripheral equipment consisted of an automated pipetting robot, a fraction collector and a gas-chromatograph equipped with an automatic injector. 

The residence time achieved with the given set-up was 100 s. The highest conversion of 53% was found with the rhodium catalyst based on the ligand tris(m-sulfophenyl)phosphane. Results gained with the micro mixer-based set-up were in good agreement with results found for a mini-batch reactor. 

The EM Modular Reaction System can also be used to perform multi-step syntheses [83], For the production of pharmaceuticals, in this case for the synthesis of vitamin A, an ylid is formed from a phosphonium salt and a base in the first stage at 2 °C. In a second stage, the ylid reacts with an aldehyde at 60 °C in a flow-through capillary reactor. In a third stage the crude product is hydrolyzed at 20 °C in an additional micro mixer to form the target product vitamin A acetate, as illustrated. For the claimed reaction, no further experimental details were given. 

Figure 4.39 shows the complete set-up used for the temperature tests. A realistic set-up was chosen by combining three heat exchangers, a glass mixer and a mixer-tube reactor with six backbone elements. Initially the micro structured reactor plant was at room temperature. 

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