Kreislaufführung von verbrauchten Katalysatoren in der chemischen Industrie

Recycling of Used Catalyst in the Chemical Industry In this article, the consumption of catalysts in the chemical industry in Germany as well as their recycling are investigated. Metal catalysts play a dominant role both quantitatively and economically. Precious metal catalysts are also used very often, however, their quantitative use is, with less than 1 000 t per annum, small and they are regularly reclaimed. The biggest group of catalysts consists of non‐precious metal catalysts and it represents ca. 9 000 t per annum. The used catalysts from this group are only partially recycled. Some of these metals are often reclaimed, such as Ni, Cr, Mo, Co, and Cu. The catalysts that are not recycled are utilized in the chemical industry or disposed of. Economical criteria, such as the price of the metal, the content of the metal, the impurities, etc., are usually decisive for the choice between recycling and disposal. The support material can also be re‐utilized or disposed of.     

Zur katalytischen Aktivität glasfixierter Übergangsmetall-komplexe

The Catalytic Activity of Glass-fixated Transition-metal Complexes The formation of p-ethyloxycarbonylphenyl isocyanate from p-ethyloxycarbonyl-phenyl azide and carbon monoxide in the presence of supported rhodium complexes, synthesized by reaction of RhCl(CO)(Ph₂PCH₂CH₂Si[OEt]₃)₂ with porous silica glasses, is followed kinetically. The glass-fixated complexes are catalytically 500–1000 times less active than the homogeneously dissolved one. Their activity decreases with increasing metal loading of the glasses. The activation energy of the heterogeneous reaction is larger than that of the homogeneous reaction, and the reaction rate is independent of the pellet diameter, the pore volume, the pore diameter, and the specific surface of the glass supports, which speaks against a retardation fo the reaction by pore diffusion.     

Innovative Katalysatoren zur oxidativen Dehydrierung in der Gasphase – Metallische Kurzfasern

Innovative Catalysts for Oxidative Dehydration Reactions in the Gas Phase – Metallic Short Fibres The catalytic activity of metallic short fibres with chosen alloy composition and texture was investigated in the oxidative dehydration (ODH) of propane to yield propene, and of isopropanol to yield acetone. The short fibres were synthesised using a melt extraction process and the properties of the fibres were intensely characterised. A correlation between the structure and the catalytic activity of the material was established. Thus, light‐optical microscopic‐, DSC‐, XRD‐, REM‐ and EDX‐methods were used to characterise the fibres. Selective results of the dependency of the temperature on the propane conversion are presented in this work. A yield of more than 35 % propene is obtained at a propane conversion of 50 %. The ODH of isopropanol to acetone occurred with attractive yields of over 80 %. The results demonstrate the high innovative potential of the metal fibre materials.