Application of Catalysts to Metal Microreactor Systems

Pfeifer, P. (2012) Application of catalysts to metal microreactor systems, in Chemical Kinetics (ed V. Patel), InTech, pp. 325-344. 

Metal-catalyzed cross-couplings are key transformations for carbon-carbon bond formation. The applicability of continuous-flow systems to this important reaction type has been shown by a Heck reaction carried out in a stainless steel microreactor system (Snyder et al. 2005). A solution of phenyliodide 5 and ethyl acrylate 6 was passed through a solid-phase cartridge reactor loaded with 10% palladium on charcoal (Scheme 2). The process was conducted with a residence time of 30 min at 130°C, giving the desired ethyl cinnamate 7 in 95% isolated yield. The batch process resulted in 100% conversion after 30 min at 140°C using a preconditioned catalyst. 

Nowadays, this method is extended to other metals such as Ti [187], Zr [188], Hf [189], and Nb [190] as well. In particular, the TiOj-based nanotubes are of special interest because of their specific potential use in optical, electrochemical, and catalytic applications [191]. The AAO has been used to functionalize and modify the walls of a microreactor and use the resulting porous system as catalyst support in ammonia reforming [192]. 

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