Miniaturized systems for homogeneously and heterogeneously catalyzed liquid-phase esterification reaction

A miniaturized-plant concept is presented for the analysis of homogeneous and heterogeneous acid-catalyzed esterification of acetic acid with butanol. The plant configuration includes a micromixer followed by an isothermal microreactor. For the case of homogeneously catalyzed esterification, a long tube of 1.3 mm inner diameter acted as the reaction tube and also helped to achieve longer residence times. The results were found to be consistent with the data from literature obtained with conventional equipment on lab scale, while deviations were seen at long reaction times and high catalyst concentrations. A novel miniaturized fixed-bed reactor (mFBR) was designed for the heterogeneously catalyzed reaction, with Amberlyst-15 as a catalyst. The performance of the mFBR was satisfactory for a very long time, was reproducible, and could be used for continuous synthesis. A change in the residence time and the reactive length can be achieved by changing the total flow rate and the number of reaction plates in the stack, respectively.