Kinetic and Scale-up Investigations of a Michael Addition in Microreactors

Microreactors are an efficient tool for process development and intensification. However, the scale-up from lab studies to small-scale commercial production is challenging, since a change in the channel dimensions requires good knowledge of heat and mass transfer phenomena. In this work, complete process development for an exothermic Michael addition is presented. In a systematic scale-up approach, kinetic studies and experimental characterization of the employed reactors provide key parameters for detailed reactor modelling. The residence time distribution, reactant mixing, and removal of reaction heat are taken into account. It is exemplarily shown how preliminary experiments can be the basis for the prediction of scale-up effects and the development of a continuous production process. Plug flow behavior and short mixing times could be confirmed for all investigated flow reactors. Furthermore, interactions of reaction kinetics and the formation of hot spots in the reactor channel were investigated. For the examined reaction, the simulations predicted the product yield under production conditions in good accuracy.