Principles and Microreactors

Contacting Principles and Microreactors 4.4.2.1 Contacting with Continuous Phases... 

Fletcher PDI, Haswell SJ, Pombo-Villar E, Warrington BH, Watts P, Wong SYF, Zhang XL (2002) Microreactors Principles and Applications in Organic Synthesis. Tetrahedron 58 4735-4757... 

Doku, G.N. Verboom, W. Reinhoudt, D.N. van den Berg, A. On-microchip multiphase chemistry— a review of microreactor design principles and reagent contacting modes. Tetrahedron. 2004, 61 (11), 2733-2742. 

The use of miniaturized reactors with characteristic dimensions below about 1 mm, so-called microreactors, is also a currently interesting development. An overview of the basic principles of microreactors is given by Emig and Klemm (2005). Details are found in Hessel, Hardt, and Loewe (2004). Subsequently, short summaries of these new concepts based on the cited literature are given. 

T. Dietrich, Principles and Applications of Chemical Microreactors (Wiley, Hoboken, 2008)... 

The same research group has further performed radical carbonylation reactions on the same microreactor system [36]. First, alkyl halides were initiated and effectively reacted with pressurized carbon monoxide to form carbonyl compounds. The principle was subsequently successfully extrapolated to the multicomponent coupling reactions. 1-Iodooctane, carbon monoxide and methyl vinyl ketone were reacted in the presence of 2,2 -azobis(2,4-dimethylvaleronitrile) (V-65) as an initiator and tributyltin hydride or tris(trimethylsilyl)silane (TTMSS) as catalyst (Scheme 15). 

In the first stage of the investigation the catalyst can be considered in the form of powder in order to derive intrinsic transient kinetics of all the relevant reactive processes. To this purpose, dynamic reactive experiments can be performed in a simple tubular fixed-bed microreactor over small quantities (50-200 mg) of finely powdered catalyst in principle, this guarantees negligible transport limitations and more controlled conditions (e.g. isothermal catalyst bed), hence enabling a direct estimation of intrinsic rate parameters by kinetic fit. Internal diffusion limitations are particularly relevant to the case of bulk (extruded) monolith catalysts, such as vanadium-based systems for NH3/urea SCR however, they... 

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