Efficient conversion of fructose to 5‐hydroxymethylfurfural by functionalized γ‐Al₂O₃ beads

Abstract

Millimeter size γ‐Al2O3 beads were prepared by alginate assisted sol–gel method and grafting organic groups with propyl sulfonic acid and alkyl groups as functionalized γ‐Al2O3 bead catalysts for fructose dehydration to 5‐hydroxymethylfurfural (5‐HMF). Experiment results showed that the porous structure of γ‐Al2O3 beads was favorable to the loading and dispersion of active components, and had an obvious effect on the properties of the catalyst. The lower calcination temperature of γ‐Al2O3 beads increased the specific surface area, the hydrophobicity and the activity of catalysts. Competition between the reaction of alkyl groups and ‐SH groups with surface hydroxyl during the preparation process of the catalyst influenced greatly the acid site densities, hydrophobic properties and activity of the catalyst. With an increase in the alkyl group chain, the hydrophobicity of catalysts increased obviously and the activity of the catalyst was enhanced. The most hydrophobic catalyst C16‐SO3H‐γ‐Al2O3–650°C exhibited the highest yield of 5‐HMF (84%) under the following reaction conditions: reaction medium of dimethylsulfoxide/H2O (V/V, 4:1), catalyst amount of 30 mg, temperature of 110°C and reaction time of 4 hr.

Glucose Conversion into 5-Hydroxymethylfurfural over Niobium Oxides Supported on Natural Rubber-Derived Carbon/Silica Nanocomposite

“…Besides, MCS and 10-Nb/MCS not only exhibited higher HMF yield and selectivity but also a lower humins yield than HMS and 10-Nb/HMS. This result was in accord with the previous work, which indicated the beneficial effect of catalyst hydrophobicity on the HMF formation [14]. Zhu et al [36] reported that HMF was rehydrated to 2,5-dioxo-6-hydroxyhexanal (DHH), which was thermodynamically unstable intermediate in the reaction system consisting of water and acid catalyst.…”

“…However, a low initial concentration of glucose feedstock (or a high catalyst loading level) and a substantial formation of humins limited the practical use of these catalysts. Recently, Lin et al [14] synthesized alumina (γ-Al 2 O 3 ) functionalized with alkyl groups a hydrophobic acid catalyst for HMF synthesis from fructose, while Yang et al [15] designed a series of hydrophobic silica nanoparticles for catalytic conversion of glucose into HMF. The effect of hydrophobic properties on retardation of HMF condensation to form humins was addressed.…”

“…Mesoporous carbon/silica nanocomposites (MCS) have attracted considerable attention in the catalytic processes for conversion of biomass-derived carbohydrates into HMF and other renewable chemicals [16]. The mesostructured silica framework provides good textural properties and thermal stability, while the carbon moieties possess hydrophobic properties that could reduce the formation of humins [14]. In addition, the carbon surface is covered with oxygen-functional groups, such as hydroxyl (−OH) and carboxyl (−COOH), which improved the adsorption of substrate molecules and dispersion of active metal species on the catalyst surface [17,18].…”

Sulfonic Acid-Functionalized Inorganic Materials as Efficient Catalysts in Various Applications: A Minireview

“…In particular, due to its acidity, the sulfonic function catalyzed the reaction while the thiol group acted as promoter of fructose conversion. Following this study, in 2019 Lin et al [80] achieved the functionalization of alumina beads with both propyl sulfonic acid and alkyl groups. Analogously to Solis study, these materials were tested as catalysts for the production of 5-hydroxymethylfurfural.…”

Prozesstechnik: Ein grüner Bruder für PET

“…Fermentiert man Zucker, entsteht Ethanol, das sich zu Bioethylenglykol verarbeiten lässt. 8,9) Bei der Dehydrierung von Zucker entsteht 5-Hydroxymethylfurfural (HMF), 10) eine Plattformchemikalie der biobasierten Furanchemie. Die Oxidation von HMF wiederum liefert den Baustein 2,5-Furandicarbonsäure (FDCA).…”