Catalyst Design for the Valorisation of Biomass-derived Furans into Aromatics
Licentiate thesis, 2023
In this work, the conversion of one type of furans, 2,5-dimethylfuran, was studied at elevated temperatures in a flow reactor by using a selection of microporous, acidic catalysts. The effluent gas stream was analysed with Fourier-transform infrared spectroscopy and mass spectrometry. Zeolitic catalysts with the MFI-framework were synthesised bottom-up through hydrothermal synthesis, with aluminium or gallium substituted in their framework. Structural analysis was performed comprising X-ray fluorescence, X-ray diffraction, physisorption, thermogravimetric analysis, scanning electron microscopy, and acidity analysis by NH3-TPD.
Both aluminium and gallium-substituted zeolites were active for converting 2,5-dimethylfuran into aromatics, of which Ga-MFI displayed superior benzene production and catalyst lifetime. Catalyst deactivation was caused by the loss of strong and extra-framework acid sites due to the coking. After deactivation towards aromatics, the intermediate products formed on weak acid sites such as 2,4-dimethylfuran, were detected as the main products.
It was found that an increase in gallium content increases catalytic activity until a limit of Si/Ga=13 was reached, at which the synthesis of the catalyst also yielded an inactive, amorphous phase. Increasing the crystallisation duration enabled approaching this limit and forming phase-pure MFI zeolite with a Si/Ga ratio of Si/Ga=17.
Mesopores were introduced to the catalyst to improve the mass transfer of reactants and products. Even though the total production of aromatics and the catalyst lifetime remained unchanged, its number of acid sites was halved implying that each acid site was able to produce twice as many aromatics.
aromatics
2,5-dimethylfuran
gallium
biomass
furans
production of aromatics
zeolites
biomass conversion
catalysis
Author
Guido J.L. de Reijer
Chalmers, Chemistry and Chemical Engineering, Applied Chemistry
Isomorphous Substitution of Gallium into MFI-Framework Zeolite Increases 2,5-Dimethylfuran to Aromatics Selectivity and Suppresses Catalyst Deactivation
Topics in Catalysis,;Vol. 66(2023)p. 1329-1340
Journal article
C. Sauer, G.J.L. de Reijer, B. Wilfinger, A. Hellman, and P.-A. Carlsson, Continuous isomerisation of 2,5-dimethylfuran to 2,4-dimethylfuran over Ga-silicate
Green Commodity Chemicals
Swedish Energy Agency (2019-006746), 2020-01-01 -- 2024-12-31.
Subject Categories
Inorganic Chemistry
Chemical Process Engineering
Materials Chemistry
Environmental Sciences
Organic Chemistry
Infrastructure
Chalmers Materials Analysis Laboratory
Areas of Advance
Materials Science
Publisher
Chalmers
KC-salen, Kemigården 4, Chalmers
Opponent: Prof. Jerker Mårtensson, Department of Chemistry and Biochemistry, Chalmers University of Technology, Sweden