Mechanosynthesis Modification MOF-Ni to the Conversion of Biomass-Derived Methyl Levulinate into Gamma Valerolactone using Functional Metal-Organic Frameworks Employing a Continuous Flow

Abstract

In this work, we present the green Ni-MOF modification by the mechanochemical process in the solvent-free route that has been prepared as hydrogenation catalyst. The zirconium-based metal-organic framework UiO-66 (MOF) at different loading of Ni, were characterized using different techniques including X-ray diffraction (XRD), N2 porosimetry, X-ray photoelectron spectroscopy (XPS), have been employed for the characterization of the structural, textural, and composition properties of the synthesized materials, respectively. The catalysts have been evaluated in the hydrogenation reaction of methyl levulinate using 2-propanol as a hydrogen donor solvent. The reaction conditions were investigated and established at 30 bar system pressure with a reaction temperature of 200 ◦C using around 0.1 g of catalyst and a flow rate of 0.2 mL/min flow rate of a 0.3 M methyl levulinate solution in 2-propanol. All catalysts employed in this work exhibited good catalytic activities under the investigated conditions, with conversion values in the 30-70% range the selectivity to Υ-valerolactone was 100% for all samples (after one hour time on stream). The highest methyl levulinate conversion and selectivity was achieved by MOF-Ni5% which can be explained by the higher dispersion content of Ni species and the highest accessibility of the Zr sites of the MOF structures even when the superficial area has been reduced.