Leuna, Germany
Leuna, Germany

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Birke P.,Parkweg 6 | Geyer R.,KataLeuna GmbH Catalysts | Hoheisel K.,KataLeuna GmbH Catalysts | Keck M.,KataLeuna GmbH Catalysts | And 2 more authors.
Chemie-Ingenieur-Technik | Year: 2012

It was shown that catalysts used in the slurry phase hydrogenation of nitroaromatic compounds are post-passivated during exhibition in air for a longer period of time. This post passivation hampers a reactivation of the catalyst and is decelerated with increasing catalyst particle size. Furthermore a fast mixing during feeding in the nitroaromatic compound into the reactor and sufficient hydrogen supply to the catalyst surface have to be ensured to avoid an oxidic attack of the nitroaromatic compound towards the nickel catalyst and to obtain a slow deactivation of the this catalyst. Aromatic amines are usually produced via catalytic hydrogenation of nitroaromatics over transition metal supported catalysts. To characterize the stability of such catalysts, the influence of the storage period of reduced and passivated Ni/SiO 2 catalysts on the catalytic activity in the hydrogenation of nitrobenzene was investigated for two different grain sizes. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Geyer R.,KataLeuna GmbH Catalysts | Kraak P.,Faradaystrasse 55 | Pachulski A.,KataLeuna GmbH Catalysts | Schodel R.,Falladastrasse 19
Chemie-Ingenieur-Technik | Year: 2012

Nickel catalysts supported on ZrO 2, TiO 2 and ZrO 2/TiO 2 mixtures performed more active, selective and stable than Ni/SiO 2 catalysts in the hydrogenation of glucose to sorbitol. This was shown by catalytic testing as well as by determination of Ni crystallite size before and after the test. The reason for the better performance was assumed to be metal-support interaction in the Ni/ZrO 2, Ni/TiO 2 and Ni/ZrO 2/TiO 2 catalysts. The influence of the nature of the support on the catalytic activity, selectivity and stability of supported nickel catalysts in the hydrogenation of D-glucose to sorbitol is shown. The hydrogenation was performed in an autoclave using aqueous glucose solution. Furthermore the catalysts were characterized by CO chemisorption, XRD, XRF and determination of the nickel metal content. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Geyer R.,KataLeuna GmbH Catalysts | Hunold J.,KataLeuna GmbH Catalysts | Keck M.,KataLeuna GmbH Catalysts | Kraak P.,Faradaystrasse 55 | And 2 more authors.
Chemie-Ingenieur-Technik | Year: 2012

Catalysts containing transition metals like nickel are frequently used in technical hydrogenation reactions. Typically their activity and selectivity are determined via metal dispersion. XRD, H 2 TPD, volumetric chemisorption of H 2 and CO pulse chemisorption were applied to determine the Ni crystallite size of Ni-containing catalysts. The methods were compared with regard to their information content and validity as well as their applicability in quality control during industrial manufacturing of catalysts. Pulse chemisorption of CO showed the best results for utilization in quality control. The Ni crystallite size of Ni-containing catalysts was determined by different techniques: XRD, H 2 TPD, volumetric chemisorption of H 2 and CO pulse chemisorption with hydrogen as carrier gas. It was shown that the most cost effective method is the pulse chemisorption of CO for quality control during catalyst manufacturing. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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