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Access type: UnknownSubject: search.filters.subject.Bifunctional catalyst

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    Linear long-chain α-olefins from hydrodeoxygenation of methyl palmitate over copper phyllosilicate catalysts
    (2022-04-05)
    Prasanseang, Warot
    ;
    Choojun, Kittisak
    ;
    Poo-arporn, Yingyot
    ;
    Huang, Ai Lin
    ;
    Lin, Yu Chuan
    Copper phyllosilicate (CuPS) was used as a bifunctional catalyst for hydrodeoxygenation of methyl palmitate (MP) to produce long-chain α-olefins without the loss of carbon backbone. The CuPS catalysts were prepared by ammonia evaporation-hydrothermal method. The crystal structure, surface area, reducibility, Cu dispersion, Cu particle size and acidity of the catalysts were examined by XRD, BET, H<inf>2</inf>-TPR, TEM, NH<inf>3</inf>-TPD and Py-IR. The existence of Cu<sup>2+</sup> species (octahedral (O<inf>h</inf>)/square planar (Sq)), Cu<sup>+</sup> and Cu<sup>0</sup> upon calcination/reduction was investigated by in situ TR-XANES. The Cu dispersion was related to the Cu<sup>+</sup> fraction in CuPS, while Brønsted acid sites (BAS) depends on Cu<sup>0</sup> particles. The MP conversion to 1-hexadecene proceeds via hydrogenation-dehydration promoted by the synergy of Cu<sup>0</sup> surface and Brønsted acid sites at the interface. The α-olefin selectivity depends on a balance between Cu<sup>+</sup> and Cu loading. The 20CuPS possessing 10% Cu<sup>+</sup> fraction, provides a high conversion of 72% with 45% α-olefin selectivity.
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    Effects of Zinc and Aluminum on the CuO Crystalline Size for Direct Dimethyl Ether Synthesis from Syngas
    (2021-09-01)
    Thongkam, Montree
    ;
    Piyabunditgul, Nanchapak
    ;
    Trisupakitti, Somsuk
    ;
    Rungrojchaipon, Pesak
    The effects of zinc and aluminum on the CuO crystalline size for direct dimethyl ether (DME) synthesis from syngas were investigated. Metal oxide catalysts were synthesized with various molar ratios of CuO by the precipitation method, and by the co-precipitation method with CuO/ZnO (CZ), CuO/ZnO/Al<inf>2</inf>O<inf>3</inf> (CZA), and CZA at ratios of 1:1, 2:2:1, and 6:3:1, respectively. The acid catalysts (γ-Al<inf>2</inf>O<inf>3</inf>, HZSM-5) were added to the metal oxide catalysts by physical mixing. The catalysts were characterized morphologically and their acidities were determined. Loading of zinc and aluminum at different ratios showed that CZA (2:2:1) gave the smallest CuO crystalline size, appropriate for the methanol synthesis reaction. γ-Al<inf>2</inf>O<inf>3</inf> has a weak to moderate acidity range, suitable for DME synthesis. Moreover, the bifunctional catalyst, CZA (2:2:1)/γ-Al<inf>2</inf>O<inf>3</inf>, had the highest surface area as well as the highest %CO conversion and %DME selectivity.