Zirconium-Containing Organic-Inorganic Nanohybrid as a Highly Efficient Catalyst for the Selective Synthesis of Biomass-Derived 2,5-Dihydroxymethylfuran in Isopropanol

By the simple assembly of zirconium tetrachloride and diethylenetriaminepentaacetic acid (DTPA), a new acid-base bifunctional zirconium-containing organic-inorganic nanohybrid catalyst (Zr-DTPA) was successfully prepared in this work, and then used for the catalytic transfer hydrogenation (CTH) of biomass-derived 5-hydroxymethylfurfural (HMF) into 2,5-dihydroxymethylfuran (DHMF) using isopropanol as the in situ hydrogen donor and reaction solvent. Satisfactorily, 98.7% HMF conversion and 95.2% DHMF yield could be achieved in 4 h at a moderate reaction temperature of 140 degrees C. After systematic studies, this excellent catalytic activity was proved to be mainly ascribed to the synergistic effect of Lewis-acidic sites (Zr4+) and Lewis-basic sites (O2- and N) with higher strengths and contents. Meanwhile, Zr-DTPA could be readily separated by filtration, when it was repeatedly used 5 recycles, its catalytic activity was not obviously changed, demonstrating that Zr-DTPA had good heterogeneity and reusability. More importantly, Zr-DTPA could also be employed to effectively catalyze the CTH of 5-methylfurfural, furfural, levulinic acid, ethyl levulinate and cyclohexanone into the corresponding products with high yields, indicating that it showed a superior universality for the selective hydrogenation of various biomass-derived carbonyl compounds.Graphical Abstract