Mixed-metal MOFs as efficient catalysts for transfer hydrogenation of furfural, levulinic acid and other carbonyl compounds

Crystalline, porous Fe-Ni mixed-metal metal-organic frameworks (MOFs), namely MIL-88B(Fe2Ni) and NH2-MIL-88B(Fe2Ni), were synthesized and characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, atomic absorption spectrophotometry (AAS) and nitrogen physisorption measurements. The MOFs were then employed as catalysts for transfer hydrogenation (TH) of biomass derivatives such as furfural and levulinic acid, and various other carbonyl compounds using 2-propanol as a sacrificial hydrogen donor. These heterogeneous catalysts are deemed to be environmentally benign, efficient and recyclable. NH2-MIL-88B(Fe2Ni) showcased good catalytic activity with low catalyst loading in short reaction time. The catalysts were recovered and reused several times without significant degradation in catalytic activity. A mechanism for the TH reaction was also proposed. As far as we are aware, this is the first report on the synthesis of furfuryl alcohol and γ-valerolactone (GVL) via TH reaction in just 60 min using a MOF catalyst.