Jovanovic J.,Laboratory of Chemical Reactor Engineering |
Rebrov E.V.,Laboratory of Chemical Reactor Engineering |
Nijhuis T.A.,Laboratory of Chemical Reactor Engineering |
Hessel V.,Laboratory of Chemical Reactor Engineering |
And 2 more authors.
Industrial and Engineering Chemistry Research | Year: 2010
Precise control over the interfacial area of aqueous and organic slugs in segmented flow in a microchannel reactor provides an attractive means to optimize the yield and productivity of a phase-transfer-catalyzed reaction. Herein, we report the selective alkylation of phenylacetonitrile to the monoalkylated product in a microchannel of 250-μm internal diameter operated in a continuous and solvent-free manner in the slug-flow regime. The conversion of phenylacetonitrile increased from 40% to 99% as a result of a 97% larger slug surface-tovolume ratio when the volumetric aqueous-to-organic phase flow ratio was raised from 1.0 to 6.1 at the same residence time. The larger surface-to-volume ratio significantly promoted catalyst phase transfer but decreased selectivity because of the simultaneous increase of the rate of the consecutive reaction to the dialkylated product. There exists an optimum flow ratio with a maximum productivity. Conversion and selectivity in the microchannel reactor were both found to be significantly larger than in a stirred reactor. © 2010 American Chemical Society.
van Eeten K.M.P.,Laboratory of Chemical Reactor Engineering |
Hulsman D.H.J.,Laboratory of Chemical Reactor Engineering |
van der Schaaf J.,Laboratory of Chemical Reactor Engineering |
Schouten J.C.,Laboratory of Chemical Reactor Engineering
AIChE Journal | Year: 2015
A novel type of rotor-stator spinning disk device is proposed which allows for the entrapment of solid particles solely by hydrodynamic means. In this new configuration, the solid rotating disk is replaced with two conjoined rotors with a variable gap spacing. Liquid is fed through the top stator and can flow out again through the rotor-rotor interior and the hollow rotation axis. Moreover, the volume between the two rotors is optionally filled with a highly porous reticulated carbon foam. It was found that particle containment was strongly improved by the presence of this reticulated foam as it hinders the buildup of centripetal boundary layer flow near the disks in the interior of the rotor-rotor assembly. These centripetal boundary layers drag along particles resulting in a loss of containment. Experiments utilizing glass beads showed that particles with a diameter down to 17.8 μm can be completely entrapped when a carbon foam is placed between the two conjoined disks at rotor speeds up to the maximum investigated value of 178 rad s-1. Additionally, the rotor-rotor gap did not have an effect on the particle entrapment level when the reticulated carbon foam was omitted and can be ascribed to the build-up of boundary layers, which is independent of rotor-rotor distance. © 2015 American Institute of Chemical Engineers.