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Influence of the support composition on the hydrogenation of acrolein over Ag/SiO₂-Al₂O₃ catalysts.

Volckmar, Claudia and Bron, Michael and Bentrup, Ursula and Martin, Andreas and Claus, Peter (2009):
Influence of the support composition on the hydrogenation of acrolein over Ag/SiO₂-Al₂O₃ catalysts.
In: Journal of Catalysis, pp. 1-8, 261, (1), [Online-Edition: http://dx.doi.org/10.1016/j.jcat.2008.10.012],
[Article]

Abstract

The gas phase hydrogenation of acrolein over supported silver catalysts has been investigated with a focus on the influence of the support acidity. Acidity has been varied by preparing silver catalysts supported on silica/alumina supports with varying SiO2/Al2O3 ratio. After the catalytic experiments the Ag catalysts exhibit similar particle sizes, as revealed with TEM (transmission electron microscopy). The acidity of the samples was estimated using TPD of adsorbed ammonia which gives the total acidity of the samples, furthermore by IR of adsorbed pyridine to identify the Brønsted and Lewis acidity. No Brønsted acidity was found, and the Lewis acidity showed a clear dependence on the support composition. It is shown that a high total acidity and a high amount of strong Lewis acid sites on the catalysts cause a low conversion of acrolein and low selectivity to allyl alcohol. The interaction of silver with the support or effects of the metal–support perimeter are discussed as possible reasons for this behaviour.

Item Type: Article
Erschienen: 2009
Creators: Volckmar, Claudia and Bron, Michael and Bentrup, Ursula and Martin, Andreas and Claus, Peter
Title: Influence of the support composition on the hydrogenation of acrolein over Ag/SiO₂-Al₂O₃ catalysts.
Language: English
Abstract:

The gas phase hydrogenation of acrolein over supported silver catalysts has been investigated with a focus on the influence of the support acidity. Acidity has been varied by preparing silver catalysts supported on silica/alumina supports with varying SiO2/Al2O3 ratio. After the catalytic experiments the Ag catalysts exhibit similar particle sizes, as revealed with TEM (transmission electron microscopy). The acidity of the samples was estimated using TPD of adsorbed ammonia which gives the total acidity of the samples, furthermore by IR of adsorbed pyridine to identify the Brønsted and Lewis acidity. No Brønsted acidity was found, and the Lewis acidity showed a clear dependence on the support composition. It is shown that a high total acidity and a high amount of strong Lewis acid sites on the catalysts cause a low conversion of acrolein and low selectivity to allyl alcohol. The interaction of silver with the support or effects of the metal–support perimeter are discussed as possible reasons for this behaviour.

Journal or Publication Title: Journal of Catalysis
Volume: 261
Number: 1
Uncontrolled Keywords: Acrolein; Hydrogenation; Ag catalyst; SiO2–Al2O3 support; Acidity
Divisions: 07 Department of Chemistry
07 Department of Chemistry > Fachgebiet Technische Chemie > Technische Chemie II
07 Department of Chemistry > Fachgebiet Technische Chemie
Date Deposited: 20 Mar 2009 08:57
Official URL: http://dx.doi.org/10.1016/j.jcat.2008.10.012
Additional Information:

Available online 12. November 2008

Identification Number: doi:10.1016/j.jcat.2008.10.012
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