Project
Dehydrogenative, electrochemical coupling reactions of aromatics with transition metal containing zeolites as catalysts.
C-H Activation allows for a more cost-effective and sustainable functionalization of aromatics. Its industrial implementation is however hampered by a low regioselectivity, by the use of costly stoichiometric oxidants, or by the hazardous use of pressurized oxygen. In this proposal, we build upon our previous discovery of shape-selectivity in the oxidative arene-arene coupling, catalyzed by Pd-zeolites. The zeolite-coordinated Pd is capable of activating specific aromatic C-H bonds. Now we expand the scope of these reactions to couplings of arenes and olefins, using not only Pd- but also Rh-loaded zeolites. Rh appears to have reactant scopes that are complementary to those of Pd. Next, we attempt to find an alternative for the use of dioxygen in these dehydrogenative reactions; therefore, we aim at relaying the electrons from the reactants to the anode of a divided electrochemical reactor. Mediators will play a key role in shuttling electrons from the zeolite-confined Rh or Pd to the anode. To create a maximally efficient system, and to allow for future applications in flow, we will design zeolite-functionalized electrodes by deposition or hydrothermal synthesis of the zeolite crystals. A combination of advanced operando spectroscopy, kinetics and electrochemical characterization will lead to a better understanding of the catalyst’s active site and the mechanisms at work.