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Hydrogenolysis of glycerol over a highly active CuO/ZnO catalyst prepared by an oxalate gel method: Influence of the solvent and the reaction temperature on the catalyst deactivation

Bienholz, Arne and Schwab, Frederick and Claus, Peter (2010):
Hydrogenolysis of glycerol over a highly active CuO/ZnO catalyst prepared by an oxalate gel method: Influence of the solvent and the reaction temperature on the catalyst deactivation.
In: Green Chemistry, pp. 290-295, 12, (2), [Online-Edition: http://dx.doi.org/10.1039/b914523k],
[Article]

Abstract

The hydrogenolysis of glycerol was performed in an autoclave at temperatures between 190 and 225 °C and at a H₂ pressure of 5 MPa over a CuO/ZnO catalyst prepared by an oxalate gel (OG) method. Compared to a CuO/ZnO catalyst prepared by coprecipitation, much higher conversions of glycerol and space–time yields up to 9.8 gpropylene glycol g(Cu)⁻¹ h⁻¹ are achieved with CuO/ZnO-OG, whereas both catalysts produced propylene glycol with selectivities of about 90%. Additionally, the influence of the temperature and the solvent was examined. Compared to a conversion of glycerol of only 5% in an aqueous glycerol solution, the use of 1,2-butanediol as a solvent leads to a high conversion of 55%. Moreover, experiments were carried out in pure glycerol and from transmission electron microscopy images of fresh and spent catalysts, it was obvious that the morphology of the catalyst changed during the reaction. By X-ray diffraction and N₂O chemisorption, it was proved that a tremendous loss of copper surface area occurred during the hydrogenolysis of glycerol. Taking together the influence of the solvent on the conversion of glycerol and the results of the catalyst characterization, it can be concluded that water, as an unavoidable by-product of the reaction, is responsible for a strong deactivation of the catalyst.

Item Type: Article
Erschienen: 2010
Creators: Bienholz, Arne and Schwab, Frederick and Claus, Peter
Title: Hydrogenolysis of glycerol over a highly active CuO/ZnO catalyst prepared by an oxalate gel method: Influence of the solvent and the reaction temperature on the catalyst deactivation
Language: English
Abstract:

The hydrogenolysis of glycerol was performed in an autoclave at temperatures between 190 and 225 °C and at a H₂ pressure of 5 MPa over a CuO/ZnO catalyst prepared by an oxalate gel (OG) method. Compared to a CuO/ZnO catalyst prepared by coprecipitation, much higher conversions of glycerol and space–time yields up to 9.8 gpropylene glycol g(Cu)⁻¹ h⁻¹ are achieved with CuO/ZnO-OG, whereas both catalysts produced propylene glycol with selectivities of about 90%. Additionally, the influence of the temperature and the solvent was examined. Compared to a conversion of glycerol of only 5% in an aqueous glycerol solution, the use of 1,2-butanediol as a solvent leads to a high conversion of 55%. Moreover, experiments were carried out in pure glycerol and from transmission electron microscopy images of fresh and spent catalysts, it was obvious that the morphology of the catalyst changed during the reaction. By X-ray diffraction and N₂O chemisorption, it was proved that a tremendous loss of copper surface area occurred during the hydrogenolysis of glycerol. Taking together the influence of the solvent on the conversion of glycerol and the results of the catalyst characterization, it can be concluded that water, as an unavoidable by-product of the reaction, is responsible for a strong deactivation of the catalyst.

Journal or Publication Title: Green Chemistry
Volume: 12
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: 22 Oct 2009 08:02
Official URL: http://dx.doi.org/10.1039/b914523k
Additional Information:

First published on the web 26. November 2009

Identification Number: doi:10.1039/b914523k
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