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Author: search.filters.author.Saenluang, KachapornHas files: No

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    Dry-gel synthesis of Ti-beta for epoxidation of unsaturated fatty acid methyl esters (FAMEs)
    (2026-09-01)
    Yomthong, Krissanapat
    ;
    Saenluang, Kachaporn
    ;
    Soyphet, Asadawut
    ;
    Ittisanronnachai, Somlak
    ;
    Padchasri, Jintara
    The Ti-beta was synthesized via a dry-gel conversion approach with the direct incorporation of titanium from titano-aluminosilicate nanobeads (Ti-SiAl-NB). At first, the Ti-SiAl-NB was prepared and employed as the precursor for zeolite crystallization. Powder XRD (PXRD) patterns confirm the amorphous nature of the nanobeads. These Ti-SiAl-NB precursors were subsequently converted to the Ti-beta zeolite via the dry-gel conversion approach. Structural characterization using PXRD, high-resolution TEM, and selected area electron diffraction (SAED) confirmed the formation of a beta zeolite framework, with dominant lattice planes indexed to (101) and (302). UV-vis DRS indicated that Ti existed as a tetrahedrally coordinated (Ti<sup>IV</sup>) and non-framework Ti. Unfortunately, the as-synthesized Ti-beta exhibited a low catalytic activity in methyl oleate (MO) epoxidation, which is attributed to the prevalence of closed site Ti<sup>IV</sup> [Ti(OSi)<inf>4</inf>] species that restrict substrate accessibility to active sites. To address this limitation, a post-synthetic treatment involving framework etching was applied to generate open site Ti<sup>IV</sup> [Ti(OSi)<inf>3</inf>OH] species. As a result, MO conversion increased by approximately 2.73-fold, with epoxide selectivity up to 70%. Catalyst stability tests demonstrated sustained MO conversion of 65–72% and epoxide selectivity above 65% over several consecutive catalytic cycles. This work highlights a sustainable catalyst design strategy that combines the dry-gel conversion process with mild post-treatment to enhance active site accessibility and catalytic performance in the epoxidation of bulky molecules.
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    Cu encapsulated in hierarchical MFI zeolites for ethanol dehydrogenation to acetaldehyde
    (2026-04-09)
    Saenluang, Kachaporn
    ;
    Maineawklang, Narasiri
    ;
    Prasertsab, Anittha
    ;
    Sooknoi, Tawan
    ;
    Kegnæs, Søren
    In this contribution, we report the design of Cu nanoparticles encapsulated within both hierarchical and conventional MFI frameworks for the dehydrogenation of ethanol to acetaldehyde. The encapsulated catalysts were successfully synthesized via a hydrothermal method, using tetrabutylammonium hydroxide (TBAOH) and tetrapropylammonium hydroxide (TPAOH) as structure-directing agents (SDAs) for hierarchical and conventional frameworks, respectively. Characterization results showed that the hierarchical silicalite-1 zeolite (Cu@hieS-1) exhibited the simultaneous presence of mesopores and uniform Cu nanoparticles (∼2.3 nm), with high Cu dispersion (82.6%), thereby significantly improving active-site accessibility and reducing diffusion path lengths, eventually enhancing catalytic efficiency. Catalytic testing demonstrated that Cu@hieS-1 achieved 96% ethanol conversion and 82% acetaldehyde yield at 400 °C, outperforming conventional zeolites (15% ethanol conversion and 12% acetaldehyde yield). The reason for the improved catalytic activity over Cu@hieS-1 compared to the conventional ones relates to the fact that Cu@hieS-1 contains a higher proportion of Cu<sup>+</sup> species compared with the others, eventually leading to promoting acetaldehyde formation. Additionally, hierarchical zeolites exhibited enhanced catalytic stability, maintaining ∼80% conversion and 82% acetaldehyde yield. This work illustrates the benefits of the encapsulated catalyst in optimizing catalytic performances for sustainable acetaldehyde production.
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