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<p>In this study, highly crystalline ZSM-22 zeolite with a TON topology was synthesized via a seed–template co-assisted hydrothermal method and subsequently modified with low-concentration NH₄Cl to introduce Brønsted acid sites. The characterization of the catalyst revealed its well-defined rod-like crystals (2–5&#xa0;μm), one-dimensional straight channels (0.46 × 0.57&#xa0;nm), microporous surface area of 210&#xa0;m<sup>2</sup>·g<sup>−1</sup>, Brønsted-to-Lewis (B/L) acid ratio of 0.45, and excellent thermal stability. Under optimized reaction conditions (270&#xa0;°C, 3&#xa0;h, 6 wt% catalyst), the catalyst achieved a 95.01% conversion of oleic acid and a 77.72% yield of isostearic acid. The confinement effect of the 1D channels effectively suppressed undesired side reactions, offering significantly enhanced selectivity compared to commercial zeolites such as ZSM-5. Thermogravimetric analysis demonstrated that calcination at 550&#xa0;°C successfully removed coke deposits and restored catalyst activity. After five regeneration cycles, the conversion and yield remained at 89.50% and 72.80%, respectively, with less than 6% loss. These findings provide theoretical and technical guidance for the high-value catalytic transformation of biomass-derived fatty acids.</p> Graphical Abstract <p></p>

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Advantages of Porous H-ZSM-22 Zeolite for Catalyzing Oleic Acid Isomerization: High Selectivity and Regeneration Stability

  • 期刊论文

  • 发表日期：

    2025年11月4日

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  • Pengyu Ge,
  • Xiyu Liu,
  • Xincheng Li,
  • Mingming Fan,
  • Pingbo Zhang

摘要

In this study, highly crystalline ZSM-22 zeolite with a TON topology was synthesized via a seed–template co-assisted hydrothermal method and subsequently modified with low-concentration NH₄Cl to introduce Brønsted acid sites. The characterization of the catalyst revealed its well-defined rod-like crystals (2–5 μm), one-dimensional straight channels (0.46 × 0.57 nm), microporous surface area of 210 m2·g−1, Brønsted-to-Lewis (B/L) acid ratio of 0.45, and excellent thermal stability. Under optimized reaction conditions (270 °C, 3 h, 6 wt% catalyst), the catalyst achieved a 95.01% conversion of oleic acid and a 77.72% yield of isostearic acid. The confinement effect of the 1D channels effectively suppressed undesired side reactions, offering significantly enhanced selectivity compared to commercial zeolites such as ZSM-5. Thermogravimetric analysis demonstrated that calcination at 550 °C successfully removed coke deposits and restored catalyst activity. After five regeneration cycles, the conversion and yield remained at 89.50% and 72.80%, respectively, with less than 6% loss. These findings provide theoretical and technical guidance for the high-value catalytic transformation of biomass-derived fatty acids.

Graphical Abstract