From stereodynamics to high-throughput screening of catalysed reactions

Abstract

Characterising chemical reactions by kinetic analysis is of fundamental importance to experimentally obtain insights into reaction mechanisms. Based on such investigations reactions can be optimised and improved catalysts designed. Enhanced reaction conditions may drastically increase the performance of the reaction in terms of yield and (enantio-) selectivity. Understanding reaction kinetics in more complex systems involving adaptive chemical and dynamic systems on a molecular level as shown here is even more challenging. Here we review recent developments in monitoring reactions including the dynamic interconversion of stereoisomers by integrating (catalysed) reactions and chemical analysis in on-column reaction chromatographic devices. These recent developments allow rapid screening of reactions in great detail and are a central tool in determining reaction pathways and to understand how to control the stereodynamics of chiral molecules.

Ruthenium Nanoparticles in High‐Throughput Studies of Chemoselective Carbonyl Hydrogenation Reactions

“…These observations confirm that the selectivity and activity of the Ru nanoparticles is mainly based on their nature, size, and stabilization in the polymeric matrix. This makes our high‐throughput micro‐flow‐reactor system comparable with a classical batch reactor system and allows the fast reaction screening of various catalytic systems …”

“…This makes our high-throughput micro-flowreactors ystemc omparable with ac lassical batch reactor system and allowst he fast reactions creening of various catalytic systems. [10][11][12][13][14][15][16] We furtheri nvestigated the activity of the Ru nanoparticle system in various hydrogenation reactions and studied their reaction kinetics. Based on the Langmuir-Hinshelwood mechanism, we calculated the activation parameters DG°, DH°,a nd DS°as well as the reaction rate constants by using af irstorder reaction rate law.T he calculation was performedu sing temperature-dependent measurements.…”

“…In this study, we used our established strategy of on‐column reaction gas chromatography (ocRGC) to investigate in detail the dependence of the catalyzed reaction on the temperature, the pressure of the reactive carrier gas (H 2 ), the catalyst loading, and the length of the active catalyst capillary. The utilization of the chromatographic technique described here allows us to perform high‐throughput experiments and achieve the direct separation and quantification of the reaction mixture, which provides easy access to kinetic data and, therefore, improves our understanding of catalysis in quasi‐homogeneous systems . This experimental setup was already used by Trapp et al.…”

“…The utilization of the chromatographic technique described herea llows us to perform high-throughput experiments and achievet he direct separation and quantificationo ft he reactionm ixture, which provides easy access to kinetic data and, therefore, improves our understanding of catalysis in quasi-homogeneous systems. [10][11][12][13][14] This experimental setup was already used by Trapp et al for detailed studies of palladium. [15,16] There are various procedures to prepare, characterize,a nd apply Ru nanoparticles.…”

Investigation of the Hydrogenation of 5‐Methylfurfural by Noble Metal Nanoparticles in a Microcapillary Reactor

“…In this respect the development of catalysts for the selective conversion is still under intense investigation.Our strategy of on-columnr eactiong as chromatography (ocRGC)w as shown to be af ast screening tool. By integration of catalysis and analysisi nasingles tep, highly reliable ande fficient reaction screeningi sm adef easible, because precise control of reactionp arameters (e.g.,t emperature and pressure) is possible.This straightforwardh igh-throughput experimental setup allows to gain complex systems [12][13][14][15][16][17][18][19] and provides the deeper understanding of catalytic systemsi navery short time scale. Information regarding the catalyst performance in dependent of the temperature and hydrogen pressure enables the development of as uitable catalytic system.T his significantly accelerates the optimization and implementation process of particular catalysts regarding possible industrial applications.…”