Catalytic Upgrading of Lignocellulosic Biomass-Derived Compounds Using Hierarchical ZSM-5 Zeolites

Abstract

Although fossil fuels are the primary energy source presently, their usage brings concerns related to the emissions of pollutants that pose risks to both human and environmental health. In this context, lignocellulosic biomass as a renewable feedstock stands out as a viable carbon-neutral energy source since it can be converted into fuel additives and several valuable products. This paper evaluated hierarchical ZSM-5 zeolites (Si/Al ratios of 23, 38, and 48) for the conversion of furfural into isopropyl levulinate. The hierarchical material was obtained through an alkaline treatment and characterized with X-ray diffraction, X-ray fluorescence, N₂ physisorption, TPD-NH₃, and Fourier transform infrared spectroscopy . Catalytic assessments and a factorial experimental design (2³) were performed, and, as a result, a FUR conversion above 90% was observed, with an apparent obtained yield of 85% for the treated Z23DS zeolite. The results indicated that the catalyst acidity, the reaction temperature, and the amount of catalyst played significant roles in conversion and selectivity values. Furthermore, the hierarchical Z23DS zeolite promoted the aldol condensation of 5-hydroxymethylfurfural with acetone into sustainable aviation fuel precursors.