2/12/2024 0 Comments Reaktor m1However, most polymeric materials tend to swell in organic solvents and thus clog the flow-through channels, whereas the pore structure of the applied silica xerogels is prevailed by small mesopores which generate a very large but hardly accessible surface area and the need for an exceedingly large overpressure.Ī breakthrough came with the development and application of silica monoliths that featured a very open multimodal macro-/mesopore structure, developed by Nakanishi et al. They featured scores of very narrow flow-through pores and greatly expanded the surface area. To overcome this limitation, polymeric, hybrid macrocellular (HIPE), or inorganic (silica) monolithic microchannel reactors (MMRs) and their carbon replicas were proposed ( Xie et al., 1999 Kawakami et al., 2005 Roucher et al., 2019 Brun et al., 2011 van den Biggelaar et al., 2019 Baccour et al., 2020). However, the throughputs in the µL/min range make microchannel reactors suitable for microsynthesis, rather than fine chemical synthesis on a multi-g/h scale. On the one hand, it improves productivity and selectivity, and on the other hand, it improves economy and process safety. The increase in the surface-to-volume ratio to over 104 m 2/m 3, featured by microchannel reactors, additionally increases the space-time yield. In such microreactors, catalysts are either coated onto the walls or embedded in porous beads packed into the channels. To conclude, the synthetic system made of the hierarchically structured monoliths, or RBRs filled with structured catalytic pellets, lay the foundation for a new platform for the high-yield production of a wide variety of specialty chemicals, even on a multikilogram scale, in a safe and sustained manner.įor decades, the synthesis of fine chemicals and active pharmaceutical ingredients (APIs) was carried out in batch operations until in the early nineties that was about to start to change, sparked by the observation that chemical reactions are better controlled and run much faster in a continuous flow, especially in channels with submillimeter diameters ( Ehrfeld et al., 2000 Stankiewicz, 2001). The production systems worked stably for at least 200 h. On the contrary, in those with the most open structure (M1) and functionalized with enzymes, it could increase by more than two orders of magnitude even at low overpressures. The results show that an increase in the flow rate and thus velocity in reactors activated with more conventional catalytic sites has no or a minor positive effect on the apparent reaction rate. We then summarized the most important results, mainly from our studies of continuous-flow structured monolithic reactors and rotating bed reactors (RBRs) filled with structured pellets, activated with various catalytic entities and enzymes. Making use of the flow hindrance of different pore structures seen from the Darcy law perspective, we discriminated four structures of the monoliths (M1–M4). In this review article, we first discussed the development of silica monoliths with hierarchical macro-/mesopore structure and their potential figures of merit as continuous-flow micro-/mesoreactors of up to 30 ml working volume. 2Institute of Chemical Engineering, Polish Academy of Sciences, Gliwice, Poland. 1Department of Chemical Engineering and Process Design, Silesian University of Technology, Gliwice, Poland.Katarzyna Szymańska 1* Agnieszka Ciemięga 2 Katarzyna Maresz 2 Wojciech Pudło 1 Janusz Malinowski 2 Julita Mrowiec-Białoń 1,2* Andrzej B.
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