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. (C) 2000 Elsevier Science B.V.
| Original language | English |
|---|---|
| Pages (from-to) | 397-402 |
| Number of pages | 6 |
| Journal | Journal of Molecular Catalysis A: Chemical |
| Volume | 159 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - 2000 Oct 2 |
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All Science Journal Classification (ASJC) codes
- Catalysis
- Process Chemistry and Technology
- Physical and Theoretical Chemistry
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Mechanisms of n-butane isomerization over superacidic sulfated metal oxides. / Yang, Tien Syn; Chang, Tsong Huei; Lin, Chiu-Hsun; Yeh, Chuin Tih.
In: Journal of Molecular Catalysis A: Chemical, Vol. 159, No. 2, 02.10.2000, p. 397-402.Research output: Contribution to journal › Article
TY - JOUR
T1 - Mechanisms of n-butane isomerization over superacidic sulfated metal oxides
AU - Yang, Tien Syn
AU - Chang, Tsong Huei
AU - Lin, Chiu-Hsun
AU - Yeh, Chuin Tih
PY - 2000/10/2
Y1 - 2000/10/2
N2 - 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. (C) 2000 Elsevier Science B.V.
AB - 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. (C) 2000 Elsevier Science B.V.
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U2 - 10.1016/S1381-1169(00)00250-8
DO - 10.1016/S1381-1169(00)00250-8
M3 - Article
AN - SCOPUS:0034597112
VL - 159
SP - 397
EP - 402
JO - Journal of Molecular Catalysis A: Chemical
JF - Journal of Molecular Catalysis A: Chemical
SN - 1381-1169
IS - 2
ER -