Hierarchical Zr-BEA zeolites as catalysts for the transformation of levulinic acid to γ-valerolactone under mild conditions

Barakov, R.; Ermakov, I.; Enbaev, Z.; Maksimov, S.; Smirnov, A.; Ivanova, I.

Авторы: Barakov Roman, Ermakov Ivan, Enbaev Zakhar, Maksimov Sergey, Smirnov Andrei, Ivanova Irina
Журнал: Microporous and Mesoporous Materials
Том: 391
Год издания: 2025
Издательство: Elsevier BV
Местоположение издательства: Netherlands
Номер статьи: 113602
DOI: 10.1016/j.micromeso.2025.113602
Аннотация: An important stage of cascade transformation of lignocellulosic biomass to value added chemicals is the conversion of levulinic acid and its ethers in γ-valerolactone, which has a potential application as a bio-based solvent, an intermediate in the production of polymers, food additives and bio-fuels. Herein, hierarchical Zr-BEA zeolites have demonstrated high catalytic performance and reusability in this reaction under mild conditions (115 °C, atmospheric pressure). The novel approach for the preparation of these zeolites with various Zr content has been proposed. This two-step post synthetic method includes dealumination of hierarchical Al BEA obtained in the highly concentrated reaction mixture followed by zirconium incorporation via wet impregnation. The hierarchical Zr BEA zeolite with the highest degree of zirconium incorporation, i.e. 42 %, calculated as the ratio of Lewis acid site concentration and Zr content, is obtained using wet impregnation in dry ethanol and ZrCl4 as a zirconium source. This catalyst provides a higher initial rate of γ valerolactone formation, which is 1.0 mmolGVL/gcath, as compared to commercially-based Zr-BEA, for which the rate is 0.2 mmolGVL/gcath. The higher reaction rate over hierarchical zeolite is associated with the improved accessibility of its strong Lewis acid sites, which are the most active in Meerwein-Ponndorf-Verley reduction. An even higher initial rate is achieved over hierarchical Zr-BEA in the conversion of butyl levulinate since this ether does not block the basic framework oxygen of active Zr–O sites, as in the case of levulinic acid. The plausible mechanism for the transformation of levulinic acid over Lewis and Brønsted acid sites has been proposed.
Добавил в систему: Бараков Роман Юрьевич

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Hierarchical Zr-BEA zeolites as catalysts for the transformation of levulinic acid to γ-valerolactone under mild conditionsстатья Исследовательская статья

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