On the Acid-Catalyzed Isomerization of Light Paraffins over a ZrO2/SO4 System: The Effect of Hydration

doi:10.1006/jcat.1994.1283

Journal of Catalysis

Volume 149, Issue 1, September 1994, Pages 181-188

https://doi.org/10.1006/jcat.1994.1283 Get rights and content

Abstract

Over a superacid ZrO₂/SO₄ system (ZS8: microcrystalline tetragonal, SO₄ content ≍ 2.6 groups per nm²), the isomerization of n-butane proceeds rapidly and with high yield of i-butane at 423 K, if the catalyst is calcined in dry air at ≍ 823 K. The active catalyst typically shows: all surface sulfates in a highly covalent form, a high concentration of strong (aprotic) Lewis acid sites, and a fairly low (though never null) concentration of (protonic) Brønsted acid sites. A partial rehydration of the catalyst gradually converts the surface sulfates first into a less covalent form and then into an ionic form, decreases the concentration of strong Lewis sites, and increases (up to a factor of ≍ 10) the concentration of Brønsted sites, while the catalytic activity is gradually extinguished. Initial activity and initial surface features can be recovered by repeating the catalyst activation step.

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Regular ArticleOn the Acid-Catalyzed Isomerization of Light Paraffins over a ZrO2/SO4 System: The Effect of Hydration

Abstract

Regular Article
On the Acid-Catalyzed Isomerization of Light Paraffins over a ZrO₂/SO₄ System: The Effect of Hydration