Presenter Spotlight: Professor Rutger A. van Santen
This year’s UGM technical symposium features lectures from MedeA users in leading chemical, pharmaceuticals, and engineering industries as well as contributions from key scientists and developers of the software technology such as VASP underlying the MedeA Environment. The UGM technical symposium is open to everyone. Our Spotlight today is on Professor Rutger A. van Santen. Modelling Catalyst Deactivation: Multiscale Modeling of Zeolite Catalysis Professor Rutger A. van Santen
Zeolites are solid acid catalysts currently of use in many industrial chemical processes. A major challenge to zeolite catalysis is the design of catalysts with improved lifetime. As we will show for the alkylation reaction catalyst lifetime is tuned by choice of reaction conditions, selection of zeolite microporous structure and catalyst acidity. The alkylation reaction produces gasoline from the reaction of isobutane with light alkene molecules. There is need to develop improved heterogenous catalysts for this process that currently is catalyzed by hazardous liquid acids.
Microkinetic simulations are presented that relate kinetics to zeolite structure, and composition. They use as input DFT quantum-chemical elementary reaction rate constants. The microkinetic equations are solved as a function of time. Reaction initiation, quasi-steady state and deactivation regimes are distinguished.
Furthermore we will introduce a coarse graining approach to microkinetics that enables us to relate deactivation times with dimensionless parameters that are functions of elementary reaction rate constants and reaction conditions. The coarse graining approach transforms microkinetic equations into macroscopic chemical engineering kinetic equations. The form of these equations varies with reaction time regime.
We will study the difference in deactivation times in a Continuous Stirred Tank Reactor (CSTR) and Plug Flow Reactor (PFR) respectively.
Simulations show that optimum catalyst functionality for the alkylation reaction requires that the zeolite has micropores with diameter larger than composed of 10 ring Al/Si tetrahedra. Proton affinity has to be high with a deprotonation energy less than a defined value. Catalyst deactivation time in CSTR increases logarithmically with proton concentration. Minimum proton catalyst concentration for long life can be calculated from expressions that depend on deactivating alkene oligomerization reaction rate and reaction rate of alkylation, that critically depends on hydride transfer rate.
Compared to PFR deactivation time in CSTR is longer by two orders of magnitude. Catalyst deactivation of the immobile reaction zone in PFR becomes independent of proton concentration when this exceeds a minimum value. Then conversion of alkene in the alkylation reaction is complete. Proton concentration is a function of catalyst bed length, contact time and reaction rate of alkylation under this condition.
As we will illustrate kinetics simulations are a useful optimization tool to resolve conflicting structure and composition requirements with respect to different catalyst functionalities.
 Chong Liu, Rutger A. van Santen, Ali Poursaeidesfahani,Thijs J. H. Vlugt, Evgeny A Pidko, and Emiel J. M. Hensen, ACS Catal. 2017, 7, 8613−8627.
 Chong Liu, Ionut Tranca, Rutger A. van Santen, Emiel J. M. Hensen,and Evgeny A. Pidko, J. Phys. Chem. C 2017, 121, 23520-23530
 Aditya Sengar, Rutger A. van Santen, Erik Steur, Johannes A. M. Kuipers, and Johan Padding , ACS Catal. 2018, 8, 9016−9033
 Aditya Sengar, Rutger A. van Santen, and Johannes A.M. Kuipers, ACS Catal. 2020, 10, 6988−7006
Professor van Santen received his Ph.D. in 1971 in Theoretical Chemistry from the University of Leiden, The Netherlands. Between 1972-1988 he worked for Shell Research in Amsterdam and Houston. In 1988 he became full Professor of Catalysis at the Technical University Eindhoven. Since 2010, he is Emeritus Professor and Honorary Institute Professor at Technical University Eindhoven. He is a member Royal Dutch Academy of Sciences and Arts and foreign associate of the United States National Academy of Engineering (NAE). He has received numerous prestigious awards. Amongst others, the 1981 golden medal of the Royal Dutch Chemical Society, in 1992 the F.G. Chiapetta award of the North American Catalysis Society, in 1997 the Spinoza Award from the Dutch Foundation for Pure and Applied Research, and in 2001 the Alwin Mittasch Medal Dechema, Germany. His main present research interests are computational heterogeneous catalysis and complex chemical systems theory. He has published over 700 papers, 16 books and 22 patents. Other internationally renowned speakers at the User Group Meeting include:
Georg Kresse (University of Vienna, Austria)
Lindsay Roy (Savannah River National Laboratory, USA)
Richard Catlow (Royal Society, UK)
Kevin Gagnon (Vertex Pharmaceuticals, USA)
This year's UGM plenary speaker presentations are open to everyone!