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Please use this identifier to cite or link to this item: http://ir.ncue.edu.tw/ir/handle/987654321/16833

Title: Mechanism of n-butane Isomerization over Superacidic Sulfated Metal Oxides
Authors: Yang, Tien-Syn;Chang, Tsong-Huei;Lin, Chiu-Hsun;Yeh, Chuin-Tih
Contributors: 化學系
Keywords: Butane isomerization;Mechanism;Sulfated metal oxide;Superacid;NH3-TPD
Date: 2000-10
Issue Date: 2013-06-05T09:36:24Z
Publisher: Elsevier
Abstract: Superacidic sulfated metal oxides were prepared by impregnating different metal oxides (or hydroxides) with sulfuric acids. The superacidic strength of prepared samples were compared by temperature-programmed desorption of ammonia (NH3-TPD) and showed a trend of HS/ZrO2>HS/MgAl2O4>HS/Al2O3>HS/Fe2O3. Catalytic properties of these superacidic samples towards isomerization of n-butane to isobutane were subsequently pursued. Both the activity and the isobutane selectivity increased with the superacidic strength of catalysts. Observed variation in the selectivity was interpreted with a difference in the reaction mechanism: A high selectivity was obtained from strong superacid sites that catalyze the isomerization through a revised monomolecular mechanism; while a low selectivity became dominated on weak superacid sites that favored a bimolecular mechanism. The relative importance of these two mechanisms was kinetically controlled by formation of different butyl carbenium ions (primary or secondary) while the n-butane reactant adsorbed on superacidic sites.
Relation: Journal of Molecular Catalysis A: Chemical, 159(2): 397-402
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