The chemical industry, one of Europe’s largest industrial sectors, is a major contributor to pollution, CO2 emissions, and waste production. A significant portion of this waste stems from solvents—particularly organic solvents, which are often toxic and environmentally harmful. As a result, solvent reduction is a key priority in the strategic agendas of chemical companies worldwide.
Our project takes this goal a step further by not only reducing solvent use in chemical reactions but eliminating solvents entirely from chemical processes. This is achieved through mechanochemistry, a technique that enables chemical transformations without solvents by employing mechanical energy, such as milling or kneading, in mechanochemical reactors like ball mills or extruders.
Specifically, our project focused on the well-known Suzuki coupling reaction, a palladium-catalyzed reaction that plays a crucial role in pharmaceutical and fine-chemical synthesis. The breakthrough of our work lies in the application of direct mechanocatalysis (DM)—a novel concept in which the catalyst is not added as a separate molecular or solid-phase component, as in traditional homogeneous or heterogeneous catalysis. Instead, the milling ball itself, made from a catalytic material, serves as the catalyst. This innovation allows for an unprecedentedly simple catalyst separation and reutilization: the milling ball can be directly removed from the reaction vessel and reused.
The ERC Proof-of-Concept (PoC) project MechanoExtrusion has successfully validated the DM principle for continuous production, demonstrating that the Suzuki reaction can be scaled up significantly. Our technical approach utilizes a twin-screw extruder as a mechanochemical reactor, where two rotating screws within a barrel apply shear forces to the reacting substances. This setup enables the continuous feeding of substrates and removal of products, marking a critical step toward industrial application.
Through this project, we aimed to further scale up the process and validate its feasibility for larger quantities in a continuous system. Our work represents a transition from a laboratory proof-of-concept to a viable innovation, offering a sustainable and greener alternative to conventional chemical manufacturing processes. By eliminating solvents, reducing waste, and enhancing catalyst efficiency, our project contributes to the broader goal of a more environmentally friendly and resource-efficient chemical industry.
