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Platinum-Bismuth Catalyzed Oxidation of Glycerol: Kinetics and the Origin of Selective Deactivation

Wörz, Nicolai and Brandner, Armin and Claus, Peter (2010):
Platinum-Bismuth Catalyzed Oxidation of Glycerol: Kinetics and the Origin of Selective Deactivation.
In: The Journal of Physical Chemistry C, pp. 1164-1172, 114, (2), [Online-Edition: http://dx.doi.org/10.1021/jp909412h],
[Article]

Abstract

The selective oxidation of glycerol to dihydroxyacetone is still a challenging task for heterogeneous catalysis and important to the chemical industry. Especially bimetallic Pt−Bi catalysts show a high initial selectivity to dihydroxyacetone in acidic media but exhibit a strong deactivation during reaction as well. This deactivation decreases activity as well as selectivity to dihydroxyacetone. Thus, only moderate yields may be achieved. In this work, product adsorption was identified as a major cause. In particular, glyceric acid, an oxidation product of the primary hydroxyl group, selectively blocks those kinds of active sites that are predominantly responsible for dihydroxyacetone formation. This could be confirmed by means of kinetic modeling. It has been proven that all catalytic experiments taken into account for the parameter estimation are free from external and internal transport limitations. A mechanism characterized by two different active sites has been derived. Glyceric acid selectively inhibits one of them, causing the observed decrease in dihydroxyacetone selectivity and catalyst activity.

Item Type: Article
Erschienen: 2010
Creators: Wörz, Nicolai and Brandner, Armin and Claus, Peter
Title: Platinum-Bismuth Catalyzed Oxidation of Glycerol: Kinetics and the Origin of Selective Deactivation
Language: English
Abstract:

The selective oxidation of glycerol to dihydroxyacetone is still a challenging task for heterogeneous catalysis and important to the chemical industry. Especially bimetallic Pt−Bi catalysts show a high initial selectivity to dihydroxyacetone in acidic media but exhibit a strong deactivation during reaction as well. This deactivation decreases activity as well as selectivity to dihydroxyacetone. Thus, only moderate yields may be achieved. In this work, product adsorption was identified as a major cause. In particular, glyceric acid, an oxidation product of the primary hydroxyl group, selectively blocks those kinds of active sites that are predominantly responsible for dihydroxyacetone formation. This could be confirmed by means of kinetic modeling. It has been proven that all catalytic experiments taken into account for the parameter estimation are free from external and internal transport limitations. A mechanism characterized by two different active sites has been derived. Glyceric acid selectively inhibits one of them, causing the observed decrease in dihydroxyacetone selectivity and catalyst activity.

Journal or Publication Title: The Journal of Physical Chemistry C
Volume: 114
Number: 2
Divisions: 07 Department of Chemistry
07 Department of Chemistry > Fachgebiet Technische Chemie > Technische Chemie II
07 Department of Chemistry > Fachgebiet Technische Chemie
Date Deposited: 16 Nov 2009 09:57
Official URL: http://dx.doi.org/10.1021/jp909412h
Additional Information:

Publication Date (Web): 9. Dezember 2009

Identification Number: doi:10.1021/jp909412h
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