USY Zeolite Immobilized Zirconium-based Coordination Polymer Catalyzed Fructose to Prepare Furandiether

2,5-Bis(alkoxymethyl)furan (2,5-Bis(alkoxymethyl)furan, BAMF) is an ideal biodiesel additive. It has high energy density, stable and symmetrical molecular structure, and is compatible with biological Higher mixing ratio of diesel. The preparation of BAMF from 5-Hydroxymethylfurfural (5-Hydroxymethylfurfural, HMF) requires a catalyst that has both the activity of catalyzing etherification and aldehyde group reduction. In recent years, researchers have used hydrogen or alcohol as the hydrogen source to develop a series of catalyst systems to realize the preparation of BAMF from HMF. However, the cost of preparation and separation of HMF is relatively high at present, and it is a more economical and simple way to convert BAMF with sugars in one-pot method. Taking fructose as an example, its conversion to synthesize BAMF requires a process of dehydration, transfer hydrogenation and etherification with multiple acid catalytic units. Therefore, the above conversion requires a multifunctional solid acid catalyst. It should be noted that the optimal requirements for the type and strength of the acidic sites of the catalyst are not consistent for each unit reaction process. For example, the dehydration of fructose usually requires strong Brønsted acid, while HMF transfer hydrogenation requires Lewis acid. However, the preparation of high-activity Lewis solid acid catalysts usually requires a violent heat treatment process such as high-temperature calcination, which is likely to cause degradation of Brønsted acid sites on the catalyst surface.



Based on the above problems, the team of Professor Lin Lu and Associate Professor Tang Xing of Xiamen University explored and established a new method for preparing multifunctional solid acid catalysts by anchoring molecular sieves at room temperature. In methanol solution, ZrO2+ component and 2-Methylimidazole (2-MeIM) can undergo coordination polymerization reaction at room temperature to obtain Zr-based Coordination Polymer (ZrCP). The dehydration and condensation of 2-MeIM and the hydroxyl on the surface of USY to form an "N-Al" bond can anchor ZrCP on the surface of the USY molecular sieve. The ZrCP anchored on the USY molecular sieve has better thermal stability. The highly dispersed Zr sites on the surface of USY provide rich Lewis acidity, and because the catalyst is prepared at room temperature, the hydroxyl groups on the surface of USY that are not involved in the condensation reaction are retained as Brønsted acid. The synthesized USY@ZrCP catalyst can catalyze the one-pot preparation of 2,5-diisopropoxymethyl furan (2,5-Bis(isopropoxymethyl)furan, BPMF) from fructose in isopropanol.