Yingnan Sun

Ethane-Bridged Organosilica Nanotubes Functionalized with Arenesulfonic Acid and Phenyl Groups for the Efficient Conversion of Levulinic Acid or Furfuryl Alcohol to Ethyl Levulinate

A series of ethane‐bridged organosilica nanotubes functionalized with arenesulfonic acid and phenyl groups (ArSO3H‐Si(Et)Si‐Ph‐NTs) was fabricated successfully by a P123‐directed sol–gel co‐condensation route combined with hydrothermal treatment with a carefully adjusted P123‐to‐bis‐silylated organic precursor‐to‐HCl molar ratio in the starting system. The morphological characteristics, textural properties, Brønsted acidity, surface hydrophobicity, and structural integrity of the carbon/silica framework were characterized. The ArSO3H‐Si(Et)Si‐Ph‐NTs materials were applied in the synthesis of ethyl levulinate from the esterification of levulinic acid and the ethanolysis of furfuryl alcohol, and the excellent catalytic activity was explained in terms of the strong Brønsted acidity, unique hollow nanotube morphology, and enhanced surface hydrophobicity. Reusability tests confirmed that ArSO3H‐Si(Et)Si‐Ph‐NTs can be reused for three or five times without a significant loss of activity.

Design of Ordered Mesoporous Sulfonic Acid Functionalized ZrO2/organosilica Bifunctional Catalysts for Direct Catalytic Conversion of Glucose to Ethyl Levulinate

Ordered mesoporous sulfonic acid functionalized ZrO2/organosilica catalysts (SO42−/ZrO2‐PMO‐SO3H) bearing tunable Brønsted, and Lewis acid site distributions were prepared by a P123‐directed sol‐gel co‐condensation route followed by ClSO3H functionalization. As‐prepared catalysts were applied in the conversion of glucose to ethyl levulinate in ethanol medium. The SO42−/ZrO2‐PMO‐SO3H‐catalyzed target reaction followed a glucose‐ethyl glucoside‐ethyl fructoside‐5‐ethoxymethylfurfural‐ethyl levulinate pathway dominated by the synergistic effect of the super strong Brønsted acidity, and moderate Lewis acidity of the catalysts. Additionally, by combining the advantages of the considerably high Brønsted (696 μeq g−1), Lewis acid site density (703 μeq g−1), optimal Brønsted/Lewis molar ratio (0.99), and excellent porosity properties, the SO42−/ZrO2‐PMO‐SO3H1.0 obtained at an initial Si/Zr molar ratio of 1.0 exhibited the highest ethyl levulinate yield (42.3 %) among the various tested catalysts. Moreover, the SO42−/ZrO2‐PMO‐SO3H can be reused three times without obvious changes in activity, morphology, and chemical structure.