<p>To address the bottleneck of insufficient catalytic activity at single acidic sites in traditional Friedel-Crafts acylation reactions, this study innovatively proposes a novel synergistic catalytic strategy combining Lewis and Brønsted acids. A Y-Hβ catalyst with dual-acid functionality and hierarchical pore structure was successfully constructed by precisely introducing yttrium ions (Y<sup>3+</sup>) into the Hβ zeolite framework through an equal-volume impregnation method. Structural characterization confirms that Y<sup>3+</sup> is anchored in the framework as [YO<sub>4</sub>] tetrahedra, establishing strong Lewis acid sites while maintaining the structural integrity of Hβ zeolite. Mechanistic studies reveal that Y<sup>3+</sup> promotes C = O bond cleavage in anhydride molecules through adsorption polarization to generate C<sup>+</sup> intermediates, while simultaneously enhancing the proton acidity of adjacent Brønsted acid sites via electronic induction effects. Under Lewis acid regulation, neighboring Si-OH-Al sites precisely donate protons to the α-position of anthraquinone, forming C<sub>10</sub>H<sub>7</sub><sup>+</sup> intermediates. The synergistic cooperation between dual acids reduces the acylation reaction energy barrier to 32.8&#xa0;kcal/mol (a 24.1&#xa0;kcal/mol reduction compared to Hβ zeolite), significantly accelerating reaction kinetics. Under optimized conditions (250&#xa0;°C, 5&#xa0;h), the reaction achieves 82.6% conversion and 80.6% selectivity, demonstrating 50.6% improvement in catalytic efficiency over Hβ zeolite. Regeneration tests verify that the Y-Hβ catalyst maintains over 90% initial activity after 5 cycles, attributed to the high stability of Y-O-Si bonds and exceptional anti-coking performance, highlighting its promising industrial application potential.</p> Graphical Abstract <p></p>

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Dynamic Acid Synergy in Y-Embedded Hβ Zeolite: Structural Tailoring and Acid Cooperativity for Enhanced Friedel-Crafts Acylation Towards 2-Ethylanthraquinone

  • Qingle Zhao,
  • Sai Geng,
  • Jialuo Yin,
  • Dazhuang Gu,
  • Bolin Zhao,
  • Anyang Shi,
  • Jingyi Lao,
  • Zhiping Wang,
  • Hailong Yu,
  • Yue Liu,
  • Huihui Wang,
  • Shiwei Liu

摘要

To address the bottleneck of insufficient catalytic activity at single acidic sites in traditional Friedel-Crafts acylation reactions, this study innovatively proposes a novel synergistic catalytic strategy combining Lewis and Brønsted acids. A Y-Hβ catalyst with dual-acid functionality and hierarchical pore structure was successfully constructed by precisely introducing yttrium ions (Y3+) into the Hβ zeolite framework through an equal-volume impregnation method. Structural characterization confirms that Y3+ is anchored in the framework as [YO4] tetrahedra, establishing strong Lewis acid sites while maintaining the structural integrity of Hβ zeolite. Mechanistic studies reveal that Y3+ promotes C = O bond cleavage in anhydride molecules through adsorption polarization to generate C+ intermediates, while simultaneously enhancing the proton acidity of adjacent Brønsted acid sites via electronic induction effects. Under Lewis acid regulation, neighboring Si-OH-Al sites precisely donate protons to the α-position of anthraquinone, forming C10H7+ intermediates. The synergistic cooperation between dual acids reduces the acylation reaction energy barrier to 32.8 kcal/mol (a 24.1 kcal/mol reduction compared to Hβ zeolite), significantly accelerating reaction kinetics. Under optimized conditions (250 °C, 5 h), the reaction achieves 82.6% conversion and 80.6% selectivity, demonstrating 50.6% improvement in catalytic efficiency over Hβ zeolite. Regeneration tests verify that the Y-Hβ catalyst maintains over 90% initial activity after 5 cycles, attributed to the high stability of Y-O-Si bonds and exceptional anti-coking performance, highlighting its promising industrial application potential.

Graphical Abstract