Synthesis and Evaluation of Acid‐base Bi‐functional MOFs Catalyst Supported on PVDF Membrane for Glucose Dehydration to 5‐HMF

Abstract

Metal‐organic frameworks (MOFs) catalysts loaded on carriers with acid‐base functional active sites could be applied widely to heterogeneous catalysis, which can promote stability and activity. In this work, we report a modulated hydrothermal (MHT) method for the direct synthesis of acid‐base bifunctional UiO‐66 catalysts grafted to modified polyvinylidene fluoride (PVDF). Firstly, PVDF was modified by dopamine hydrochloride (PDA) in trimethylol aminomethane (tris) buffer, named as PDA@PVDF. Secondly, UiO‐66 material was produced via the coordination of organic ligands with zirconium ions, and could be directly loaded onto PDA@PVDF. Moreover, MHT synthetic approach can be used to synthesize other identical structures MOFs with acid, base and acid‐base catalysts by adjusting the ratio of monosodium 2‐sulfoterephthalate and/or 2‐aminoterephthalic. The obtained materials were characterized, and the catalytic performances of glucose to 5‐hydroxymethylfurfural (5‐HMF) have been evaluated. The developed facile reaction system with UiO‐66 MOFs catalysts offers a new route to large‐scale economical viable processes of carbohydrates conservation to 5‐HMF.

Unraveling the Reaction Mechanism and Active Sites of Metal–Organic Frameworks for Glucose Transformations in Water: Experimental and Theoretical Studies

“…A few studies have evaluated the catalytic activity of other MOFs, that is, MIL-101­(Cr) and ZIF-8­(Zn), for the glucose isomerization. , The main goal of these research studies was the improvement of the MOF properties (via metal clusters or organic ligands) to be applied for the one-pot synthesis of HMF from glucose. − Zr-containing MOFs UiO-66­(Zr) and Zr-MOF-808 have been tested for this one-pot transformation using dimethylsulfoxide as a solvent, obtaining moderate HMF yields (21 and 31%, respectively), probably because of the weak Brønsted acidity of the hydroxyl groups on metal clusters . However, they have been described as active materials for Meerwein–Ponndorf–Verley reduction reactions, and therefore, they are good candidates to study the glucose transformation reactions in water.…”

Highly Efficient One-Pot Conversion of Glucose to 5-Hydroxymethylfurfural over Acid–Base Bifunctional MCM-41 Mesoporous Silica under Mild Aqueous Conditions

“…Particular efforts are being made to develop environmentally friendly heterogeneous catalysts instead of homogeneous ones because of the ease of their convenient separation and recycling procedures for the former. , In relation to the heterogeneous catalyst, more efforts have been dedicated to immobilize both acidic and basic sites on a single support. Until now, a wide range of support materials such as halloysite nanotubes, metal–organic frameworks, − zirconia, mesoporous silicas, graphene oxide, activated carbon, and porous nitrogen-doped carbon have been widely employed for preparing acid–base bifunctional catalysts. While these reports have greatly promoted the conversion of glucose to HMF, most of them suffer from a low yield of HMF, the consumption of ionic liquids and/or organic solvents or biphasic systems, and the use of hazardous metals.…”

Zn(II)/Cd(II)-Based Metal–Organic Frameworks as Bifunctional Materials for Dye Scavenging and Catalysis of Fructose/Glucose to 5-Hydroxymethylfurfural

“…A typical strategy for the synthesis of HMF is the dehydration reaction of fructose/glucose using a variety of catalytic materials such as metal complexes and oxides, metal halides, ion-exchange resins, zeolites, functionalized carbonaceous materials, functionalized mesoporous materials, acidic ionic liquids (ILs) including organic inorganic acids, etc. − The main drawback for some of these catalytic systems such as equipment corrosion and difficult product isolation, low product yield, longer reaction times in the case of solid acid catalysts, and the low thermal stability of the resin-based catalysts hampering reaction efficiency. Even though a handful of MOF-based catalysts for fructose to HMF production is available in the literature, the design and development of stable and efficient catalysts are in demand considering the industrial importance of HMF. − MOFs with a highly porous and ordered nature with coordinatively unsaturated metal sites and an organic ligand component with inherent functional groups or the introduction of desired functional groups into MOFs through postsynthetic modification (PSM) can probably promote substrate transfer within the MOF catalyst in facilitating HMF production by an efficient catalytic reaction.…”