Reaction Processes and Process Coupling
Another research direction of the PCF group concerns reaction engineering and aims to develop and validate new reactor concepts. Of particular interest are concepts exploiting direct combinations of reactions with separation processes and forced periodic reactor operation, for example the application of a modulation of input parameters (e.g. feed concentrations or/and flow.
The basic information required for quantitative description of chemical reactions concerns the reaction mechanisms and kinetics. Significant efforts are made to identify reaction networks and to derive and parameterize suitable rate equations for different homogeneously catalyzed reactions. These activities were mostly carried out in cooperation projects. A heterogeneous catalyst, attractive for the industrially relevant conversion of ethene to propene (ETP reaction) was synthesized and evaluated together with Professor Alvarado (Zacatecas, Mexico). Together with the PSD group we developed a new model describing the reaction kinetics of the methanol synthesis under dynamic operating conditions. Within the “InPROMT” project, funded by the German Science Foundation (DFG) we study together with colleagues in Berlin, Dortmund and Magdeburg specific homogeneously catalyzed industrially-relevant hydroformylations reactions and, more recently, hydromethylaminations of long chain olefins.
An interesting and classic problem in chemical reaction engineering relates to evaluating the potential of a forced periodic operation of chemical reactors. Applying the Frequency Response Analysis (FRA) approach, in recent years and in close collaboration with the group led by Professor Menka Petkovska at the University of Belgrade we study possibilities for identifying the type of reactions and reactor operation for which forced periodic operation can be advantageous.
In the last two years our group has estabslished a very fruitful cooperation with the group led by Professor Peter Seeberger (MPI for Colloids and Interfaces, Potsdam-Golm) concerning the development of continuous reaction and separation processes. The focus was the efficient provision of artemisinin-based anti-malaria drugs, for which thre is increasing demand.The pathway that was investigated starts with the leaves of the artemisinin containing plant Artemisua annua and continues to the final drugs (e.g. artesunate). The starting idea of the project was the development of an efficient photocatalytic reaction capable of transforming dihydroartemsinic acid (DHAA) into artemsinin. Within this cooperation our PCF group initially developed two separation modules exploiting crystallization and chromatography. Recently two new research directions were followed, namely starting with a real plant extract and studying the photooxidation step in more detail. The most important finding so far is the fact that co-extracted chlorophyll can entirely substitute earlier added photo-sensitizers. Exploiting the available knowledge regarding solid-liquid extraction, we perform systematic extraction studies devoted to generate optimal feed compositions for the partial synthesis step having already in mind requirements originating from the finally needed separation steps.