Helical falling film microreactor

Figure 4.30 Helical falling-film microreactor (right). Flow of the liquid in the helical microchannel, visualized by injection of a fluorescent tracer (by courtesy of Elsevier and IMM) [266].

Discovery Technologies) with a circular arrangement of 12 screw-capped gas-tied glass tubes agitated by magnetic stirring. The second reactor is a commercial pressure batch reactor with a turbine and baffles (Series 4590 from Parr Instruments). The third reactor was the helical falling-film microreactor. 

Figure 4.57 Reaction performance comparison of three reactors with the most active catalysts Rh/Josiphos and Rh/Diop. Caroussel (car), helical falling-film microreactor (p) and Parr (batch) reactor (by courtesy of Elsevier) [266]. 9% conv. and 46% conv. denote a fixed conversion of 9 and 46%, respectively, which have to be achieved.

Enantioselectivity was roughly the same for the three reactors, being 80-90 and 62-65% for the Rh/Josiphos and Rh/Diop catalysts, respectively [266]. Conversion was very different. For fixed reaction time, the batch reactor and the falling-film microreactor had higher conversions than the Caroussel reactor. This was indicative of operation under mass transfer regime in the latter. On the basis of these data, it was concluded that the mass transfer coefficients kya of the helical falling-film microreactor are in between the boundaries given by the known kta values of 1-2 s 1 for small batch reactors and about 0.01 s-1 for the Caroussel reactor. 

Caroussel (car), helical falling film microreactor Source By courtesy of Elsevier [53]. 

---