Andreas Seidel-Morgenstern, Max Planck Institute for Dynamics of Complex Technical Systems
Annual Cary Lecture
"Chromatography and crystallization: Competitors and partners to provide pure enantiomers and plant ingredients"
The development of efficient separation processes is an important task for chemical engineers. The widely used and well-understood “working horse” distillation is not always applicable. For isolating and purifying fine chemicals selective crystallization and chromatography offer potential for resolution under mild conditions. These two techniques are often seen as competitors. However, due to the difficulty of many separation tasks, it is frequently not possible to solve separation problems exploiting just a single technology. The presentation will describe two types of problems, where joining forces is attractive. At first we will introduce the different types of phase diagrams of chiral compounds as the basis for a rational development of enantioselective separation processes. In the simplest but rare case that the enantiomers crystallize as a conglomerate, it is possible and attractive to apply exclusively preferential crystallization. A productive new continuous process exploiting two coupled fluidized beds will be described in more detail. However, enantiomers can frequently form racemic compounds. Thus, enriched feed solutions are required for enantioselective crystallization. Enrichment can be provided by a partial selective synthesis or by a suitable preliminary separation process. We will describe for an industrially relevant drug component an efficient combination of preparative chromatography with subsequent selective crystallization.
In a second part we will focus on mixtures, which contain a target component together with a larger number of other components. We will consider as an example the provision of artemisinin, which can be extracted from sweet wormwood (Artemisia Annua). Artemisinin and several of its derivatives are currently the basis for the most effective drugs to cure the malaria disease. To improve the overall yield of artemisisin a continuous photo-catalytic synthesis from the co-extracted precursor dihydroartemisinic acid is available. Purification using direct crystallization and center-cut simulated moving bed chromatography have been investigated, together with continuous synthesis of artesunate as one of the mentioned derivatives. A particular complex separation problem arises for feed solutions originating after applying longer extraction times in order to co-extract also sufficient amounts of chlorophyll, recently found to be an efficient green photo-catalyst. Finally, we will consider recycling concepts required to develop efficient processes. Enantioseparation combined with racemization and recycling of the counter-enantiomer will serve for illustration.
Andreas Seidel-Morgenstern received in 1982 a Diplom in Chemical Engineering from Technische Hochschule Leuna-Merseburg and in 1987 a Ph.D. from the Institute of Physical Chemistry of the Academy of Sciences in Berlin (East). In 1991 and 1992 he was a postdoctoral fellow at the University of Tennessee in Knoxville. He finalized in 1994 a Habilitation at the Technical University Berlin. After working for the pharmaceutical company Schering in Berlin he became in 1995 Professor for Chemical Process Engineering at the Otto von Guericke University in Magdeburg. In 2002 he was appointed as a Director at the newly founded Max Planck Institute for Dynamics of Complex Technical Systems in Magdeburg, where he is head of the department “Physical and Chemical Foundations of Process Engineering”.
The research interests of Andreas Seidel-Morgenstern include heterogeneous catalysis, adsorption and preparative chromatography, crystallization and the development of new reactor concepts. The results of his work are published in more than 500 research papers. He holds more than 20 patents in the fields of crystallization and multi-column chromatography.
Andreas Seidel-Morgenstern received in 1999 the “Max Buchner Award” (DECHEMA/Germany), in 2002 the Otto von Guericke Research Award of Otto von Guericke University Magdeburg, in 2015, together with Peter Seeberger, the “Humanity in Science Award” (The Analytical Scientist, UK, Phenomenex, USA), 2016 the “Emil Kirschbaum Medal” (PROCESSNET, Platform of Chemical Engineering in Germany) and in 2021 the ACS Award for Affordable Green Chemistry (together with Kerry Gilmore and Peter Seeberger. He holds Honorary Doctorates of the University of Southern Denmark (Odense, Denmark) and the Lappeenranta University of Technology (Finland) and is member of the Berlin-Brandenburg Academy of Sciences and Humanities (BBAW) and the German National Academy of Science and Engineering (Acatech). Since 2019 he is the President of the International Adsorption Society (IAS).