The Beckmann rearrangement of cyclohexanone oxime in oleum as a fast exothermic reaction model is carried out in an adiabatic multiphase microchemical system. A severe coalescene is observed due to the high viscosity of the rearrangement mixture, which decreases the reaction rate and selectivity. Gas agitation is introduced into the microsystem to enhance the reaction by reducing the coalescene and providing an evaporation space to carry away reaction heat. The effects of gas agitation on dispersion performance and mass-transfer rate have been investigated. The acid droplets diameter ranges from about 44 to 20 mm, decreasing with the increase of the gas flow rate. The overall volume masstransfer coefficient in the microsystem ranges from 0.16 to 0.74 s 21 , 1.5-3.8 times larger than that without gas agitation. The reaction performance is evaluated under different conditions and better conversion and selectivity are obtained.

The application of a membrane dispersion microreactor provides a highly efficient alternative for the synthesis of PVB.

No abstract

No abstract

A micromixing scale is proposed to characterize the micromixing performance of microdevices. It is defined to be the smallest scale within which homogenization is realized only by molecular diffusion, indicating the homogeneous mixing ability of a certain microdevice under specific operating conditions. An approach that integrates numerical simulation with experimental measurement was developed to establish the correlation between micromixing scale and segregation index. The Villermaux-Dushman reaction was conducted in a T-junction micromixer to determine its micromixing scales. The validity and reliability of this new approach is demonstrated by employing another parallel competing reaction based on both the simulation results and the experimental data.