Microbubble reactor

Further developments of this concept go toward cytometric assays [40-43] and comprise novel microreactors such as a microbubble reactor that allows for assaying living yeast cells (Saccharomyces cerevisiae), too [44]. 

To achieve an even higher degree ofnumberingup, a modular microbubble column reactor was developed that contains a stack of microstructured plates. The construction encompasses five different assembly groups, a cylindrical inner housing, which... 

With the use of falling-film microreactor or a microbubble column, yields of up to 28% were obtained with acetonitrile as solvent at conversions ranging from 7 to 76% and selectivities from 31 to 43% with regard to the monofluorinated product [308]. With the use of dual-channel reactor, conversions from 17 to 95% and selectivities from 37 to 10% were achieved using methanol as solvent [274]. The conversion of a laboratory bubble column, taken for comparison, ranged from 6 to 34% with selectivities of 17-50%, which is equivalent to yields of 2-8% [308],... 

The mass transfer efficiency of the falling-film microreactor and the microbubble column was compared quantitatively according to the literature reports on conventional packed columns (see Table 4.3) [318]. The process conditions were chosen as similar as possible for the different devices. The conversion of the packed columns was 87-93% the microdevices had conversions of 45-100%. Furthermore, the space-time yield was compared. Flere, the microdevices resulted in larger values by orders of magnitude. The best results for falling-film microreactors and the microbubble columns were 84 and 816 mol/(m3 s), respectively, and are higher than conventional packed-bed reactors by about 0.8 mol/(m3 s). 

To conclude, geometric disorientation is the most preferrable form of the FIA channel, since it combines ease of production with excellent radial mixing, while offering a low flow resistance and smooth passage so that unwanted microbubbles or solid particles are not entrapped. Also the volume/surface ratio of these reactors is larger than in packed reactors, which is an important feature for most FIA applications, where interaction between the solutes and the channel surface is not desired. 

The fluorination of toluene with 10% F2 in N2 by using the falling-film microreactor and the microbubble column has also been studied (Scheme 8.7) [11, 12]. Both the falling-film microreactor and the microbubble column offer advantages over conventional reactors in fluorination reactions. The selectivity of the formation of monofluorinated toluene in a falling-film microreactor is significantly higher than... 

FFMR, falling film microreactor PBMR, packed-bed microreactor MM, micromixer MBC, microbubble column MMR, microstructured mesh reactor SCR, single-channel reactor... 

Since power ultrasound is capable of generating extremely high pressures and temperatures within microbubbles in a liquid medium the possibility arises that sonochemistry might replace conventional (and expensive) high pressure reactors. Power ultrasound has been found to dramatically reduce the temperatures and pressures required for the preparation of early transition metal carbonyl anions from the direct reaction of the corresponding metal chlorides with carbon monoxide (Scheme 10.6) [18]. In this particular case the yield of V(CO)6 (35%) can be obtained at 4.4 atmos pressure and 10°C whereas conventional methodology requires 200 atmos and 160°C. 

Dispersed-phase contacting, obtained when one of the fluid phases is dispersed into the other phase. Examples are microbubble columns and micro-pacJced-bed reactors. 

---