Flow-chemistry Reactors for Catalysis

Chemical synthesis by conventional batch chemistry is often a labor-intensive task as the products must be separated from the educts and intermediates using various physico-chemical methods. Moreover, the reaction conditions are difficult to be controlled due to local differences in concentration, pH or temperature. An alternative approach with already multiple use-cases ranging from research to large-scale industrial usage are flow-chemistry reactors. They provide a tight control over the reaction conditions combined with an increased space-time yield compared to the batch setup. In flow reactors, the stoichiometry is defined by the concentrations and flow rates of the various reagents, and the residence time by the flow rate and interaction distance. We use microfabrication techniques in our BRNC clean room facility to create silicon-based microreactors. These microreactors feature both a rigid architecture and tailored surfaces that are resistant against corrosive solvents and can be structured in various ways and into the third dimensions. Furthermore, silicon manufacturing offers the opportunity to integrate micro- and nanoscale features for enhanced control and/or initiation of chemical reactions, including directed electrical fields, local heaters, on-line analytics etc.

This solid-state architecture is the experimental platform to perform various types of chemical catalysis. By a site-selective surface functionalization, we can immobilize catalysts on the reactor’s surface to conduct heterogeneous catalysis where the substrate-catalyst interaction sequence can be combinatorially changed, leading to large product libraries of chemically diverse compounds. Online-analytics is used for instance to study the local build-up of the catalyst or its chemical integrity / fatigue over reaction time. Multiple reactors can be coupled together via 2D or even 3D microfluidcs, and coupled to suitable analytics to create a feedback loop that can be used to optimize yields in automated systems, a feature also employed in our chemical computing projects.

The overall goal of our project is to screen reaction pathways and to discover new catalytic routes with use cases in divergent and combinatorial catalysis, molecular factory, electrochemical conversion, or electro synthesis. One most recent application within these use cases is upcycling of greenhouse gases to added-value chemicals.

Projects & funding

This work is funded by the Swiss National Science Foundation (SNSF) under the grant number 51NF40-182895 (National Center for Competence in Research (NNCR) Molecular Systems Engineering).

Collaborators

Within the NCCR Molecular Systems Engineering, we collaborate with the University of Basel (Groups of Prof. Marcel Mayor, Prof. Christof Spar, Prof. Cornelia Palivan) and ETHZ D-BSSE (Prof. Martin Fussenegger). Further collaborations are with the University of Bern (Group of Prof. Peter Broekmann).