Magnetic Fe3O4 nanoparticles and ZrO2-doped mesoporous MCM-41 as a monolithic multifunctional catalyst for γ-valerolactone production directly from furfural

Abstract

A magnetically-recoverable multifunctional catalyst (Fe3O4/ZrO2@MCM-41) was tailored by the impregnation of ZrO2 supported on mesoporous MCM-41 coated Fe3O4 nanoparticles, which successfully served as a monolithic catalyst for the cascade conversion of furfural (FAL) giving high yield to γ-valerolactone (GVL), a versatile platform molecule. The ordered hexagonal framework of the parent MCM-41 well reserved after the embedding of Fe3O4 and ZrO2. The incorporation of Fe3O4 could not only impart the catalyst with a strong magnetism, but also tune its acidity to promote GVL production. An impressive yield of 85% was accomplished straight from FAL processing with iso-propanol as a hydrogen donor and solvent. The kinetic study demonstrated higher activation energy for levulinate-to-GVL step (86.9 kJ/mol) than FAL transfer hydrogenation (35.0 kJ/mol) and subsequent alcoholysis process (51.0 kJ/mol). The catalyst could be fully recovered by an external magnetic field and showed good reusability. The sustainability of this conversion represents greatly improved by the process intensification based on one-pot reaction, magnetically-recoverable multifunctional catalyst, and mild operating conditions without using gaseous hydrogen.