Mechanochemical vs impregnation synthesis of metal oxides from pyrolyzed MOFs in microwave-assisted methyl levulinate conversion to gamma-valerolactone

A series of bimetallic oxides (Al2O3-ZrO2@C) has been synthesized using a metal-organic-framework (NH2-UiO-66) as a sacrificial agent by both impregnation and mechanochemical methods. The synthesized materials were used in heterogeneous catalysis for the direct conversion of a promising biomass-based building block, i.e., methyl levulinate to γ-valerolactone (GVL). A complete set of characterization, including N2 adsorption/desorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FTIR) was carried out. The incorporation of aluminum into the catalyst system led to a significant increase in the GVL yield. The conversion rate achieved with the mechanochemistry-based samples doubled that obtained by the impregnation samples. The material prepared via mechanochemistry with the larger Al2O3/ZrO2 ratio exhibited the greatest catalytic activity, i.e., 79 % conversion and 87 % selectivity. GVL is considered a promising biomass-derived platform chemical for numerous applications, including bio-materials, fuels or fuel additives, and various chemical intermediates. © 2025