Investigation of the structure-activity relationship of noble metal based catalysts in teh continuous, base-free oxidation of 5-(hydroxymethyl)-furfural

• Applicant: Professor Dr. Jan-Dierk Grunwaldt
• Subject Area: Technical Chemistry
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 574483742

This proposal explores the continuous and base-free oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) and the oxidative esterification to 2,5-furandicarboxylic acid dimethyl ester (FDMC). They are promising routes for producing bio-based monomers. A well-known application example is the further processing into polyethylene furanoate (PEF), which is considered an alternative packaging material to PET (polyethylene terephthalate). The aim of this project is the base-free and continuous oxidation of HMF using noble metal-based heterogeneous catalysts, mostly conducted in the presence of bases and in batch reactors. In contrast to conventional substrates, little is known about the mechanism and structure of the catalyst. This would be important in order to obtain new impulses. Therefore, these investigations are to be coupled with in-situ and operando spectroscopic methods. Continuous operation in the liquid phase has been successfully tested in initial experiments, and in-situ and operando methods at synchrotron facilities become now more easily accessible for liquid phase reactions at elevated pressure, making them an extremely attractive and novel tool in this area. The project is structured into three workpackes (WPs). In WP1, catalysts based on Au, Pt, Pd, and Ru will be synthesized and their catalytic activities in both the oxidation and the oxidative esterification reaction will be tested. Throughout the project, promoters that enhance activity/selectivity will also be applied. These can also serve as “probes” for the surface in synchrotron-based spectroscopic methods. In the next step, in WP2, in-situ spectroscopic methods, particularly X-ray absorption spectroscopy, will be applied under dynamic conditions to investigate time-resolved changes in the catalyst structure and oxidation state. This, supported by DFT-calculations and simulations, will give insight into the structure and the active site of the catalyst. This also enables the optimal reaction parameters to be determined. Complementary investigations using infrared spectroscopy and surface-enhanced Raman scattering will provide insights into adsorbed species. In WP3, deactivation/reactivation studies will be conducted. Using the complementary spectroscopic methods will help to identify and understand the structural changes during de-/reactivation processes. This will further support the knowledge-based development of the next generation of catalysts. By connecting synthesis, testing, and detailed in situ/operando studies on this important example, we will gain valuable insights that will guide us to the systematic advancement of heterogeneous catalysts in the field of continuous liquid-phase oxidation of organic molecules.

• DFG Programme: Research Grants