Regensburg 2022 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 3: Focus Session: Single Atom Catalysis 1
O 3.5: Vortrag
Montag, 5. September 2022, 11:45–12:00, H4
Assessing the environmental benefit of palladium-based single-atom heterogeneous catalysts for Sonogashira coupling — •Dario Faust Akl1, Dario Poier1,2, Sharon Mitchell1, Roger Marti2, Gonzalo Guillén-Gosálbez1, and Javier Pérez-Ramírez1 — 1Institute of Chemical and Bioenginnering, ETH Zurich, Switzerland — 2ChemTech, HEIA Fribourg, Switzerland
The Pd-Cu catalyzed Sonogashira coupling of terminal alkynes and aryl halides is a cornerstone organic transformation. A cradle-to-gate life cycle analysis (LCA) reveals a two orders of magnitude potential improvement in process footprint when replacing an organometallic Pd catalyst with a heterogeneous analogue. The latter could be easily separated permitting full Pd recovery and catalyst reuse. Heterogeneous catalysts based on isolated metal atoms (single-atom catalysts, SACs) demonstrate promising potential to synergize the benefits of solid and molecular catalysts for efficient Pd utilization. By anchoring Pd atoms on nitrogen-doped carbon we achieve full recovery of the metal, allowing catalyst reuse over multiple cycles. A hybrid process using the Pd-SAC with a homogeneous CuI cocatalyst is more productive than a fully heterogeneous bimetallic Pd-Cu SAC, which deactivates severely due to copper leaching. In some scenarios, the LCA-based metrics demonstrate the process footprint of the hybrid SAC system is leaner than the purely homogeneous counterpart already upon single reuse. Combining LCA with experimental evaluation could guide the design of reusable catalysts for more sustainable organic transformations.