Selective Hydrogenolysis of 5‐Hydroxymethylfurfural to 2‐Hexanol over Au/ZrO₂ Catalysts

Abstract

2-Hexanol (2-HOL) is a versatile biomass-derived platform molecule for synthesis of liquid transportation fuels, lubricants, or detergents. Herein, a one-step preparation of 2-HOL using 5hydroxymethylfurfural (HMF) as a substrate was reported for the first time. Several Au-based catalysts supported on different metal oxides were prepared to explore the relationship between carrier and catalytic activity. The results showed that the highest 2-HOL yield of 65.8 % was obtained at complete HMF conversion over the 5 %Au/ZrO 2 catalyst. The 5 %Au/ZrO 2 catalyst exhibited excellent durability after five consecutive recycling runs, while confirming its remarkable ring-opening hydrogenolysis on other biomass-derived furanics, furfural, with a total yield of 1-pentanol and 2-pentanol of 67.4 %. The distinguished ring-opening hydrogenolysis performance of the Au/ZrO 2 catalyst originated from a synergistic effect between the interfacial Au-O-Zr oxygen vacancies-induced Lewis acidic sites (activating CÀ OH/C=O bonds) and metallic Au (activating H 2 ). This work provides a possibility for producing 2-HOL from HMF with high yield, expanding the sustainable application of lignocellulosic biomass.

Identifying Metal–Halogen Bonding for Hydrogen-Induced Acid Generation in Bifunctional Catalysis

“…The support usually plays an important role in the activity of catalysts due to the different sizes of metal nanoparticles and their interaction with the support. , Pt and Pd have been selected as metals generating acidity with Ru as a reference for the preparation of carbon-supported catalysts.…”

Synergistic Catalysis for Promoting Ring-Opening Hydrogenation of Biomass-Derived Cyclic Oxygenates

“…Interfacial oxygen vacancies can also induce the formation of Lewis acid sites to facilitate the ring-opening hydrogenation of furanic compounds over multifunctional catalysts. Ma and Li coreported a Au/ZrO 2 catalyst for the ring-opening hydrogenation of 5-hydroxymethylfurfural to 2-hexanol, 106 where the Lewis acid sites associated with the interfacial oxygen vacancy of Au− O−Zr adsorbed the furanic oxygen and cooperated with metallic Au to enhance the ring-opening hydrogenation activity of intermediate 2,5-dimethylfuran. Compared with the 5% Au/ TiO 2 catalyst, an approximate 3-fold product yield of 2-hexanol obtained on the 5% Au/ZrO 2 catalyst is ascribed to its higher oxygen vacancy concentration of 8.507 × 10 15 spins g −1 than that of 5.851 × 10 15 spins g −1 on 5% Au/TiO 2 .…”