Catalyst Design for the Valorisation of 2,5-Dimethylfuran into Aromatics

Doktorsavhandling, 2025

In 2025, the urgency for global action against climate change is greater than ever. The transition of the chemical industry from fossil- to biomass-based feedstocks plays a central role. In this work, the catalytic conversion of biomass-derived 2,5-dimethylfuran into aromatics, essential chemical building blocks, is investigated.

The relationship between the properties of the catalyst—i.e., its framework, acidity, and porosity—and its catalytic performance—i.e., its activity, selectivity, and stability—was evaluated in a flow reactor for a series of zeolites, zeotypes, and metal oxides. Medium- and large-pore frameworks such as MFI, BEA, and FAU display the best catalytic performance due to favourable steric effects. Isomorphous substitution with gallium (Ga) instead of aluminium (Al) increases the production of aromatics and the lifetime of the catalyst, ascribed to a higher fraction of strong Brønsted and Lewis acid sites. Increasing the Al or Ga content leads to a higher acid site density and improved catalytic performance, until a framework- and element-specific threshold is reached, beyond which excessive coking causes catalyst deactivation. Introducing a secondary pore network of meso- and macropores enhances the transport of reagents and products, increasing both the accessibility and activity of each acid site.

This thesis identifies key design principles and proposes that the optimal catalyst combines a microporous framework to steer selectivity towards BTX, a high but controlled metal content and acid site density to maximise activity, and a hierarchical porosity to improve mass transport.