Emmanuel Auer

Supported iridium catalysts — a novel catalytic system for the synthesis of toluenediamine

Abstract This paper deals with the preparation, characterization, and testing of a new modified iridium catalyst for the selective hydrogenation of dinitrotoluene (DNT) to toluenediamine (TDA) in liquid phase. The new catalyst does thoroughly avoid the formation of ring-hydrogenated and incompletely converted side-products that are frequently observed in the presence of supported palladium catalysts. Moreover, the catalytic hydrogenation of DNT with supported iridium catalysts is also accompanied by an extremely low amount of undesired dimers and oligomers (“tar formation”) in comparison to industrially applied standard Pd/C or Pd-Fe/C catalysts.

New catalytic systems for the selective hydrogenation of halogenated aromatic nitro compounds

Abstract For the selective reduction of halogenated aromatic nitro compounds a new modified supported iridium based catalyst system has been developed. These catalysts are characterized by a high activity combined with an extreme low rate of dehalogenation. Moreover, the formation of other undesired side products such as azo- or azoxy- compounds can be widely avoided. The new modified indium system is an interesting alter-native to existing supported platinum and modified platinum catalysts in this application.

Stereoselective reductions of aromatic compounds

Mono- and bimetallic Rh catalysts were evaluated for the stereoselective reductive amination of alkylphenols to the corresponding alkylcyclohexylamines. Rhodium catalysts as well as bimetallic catalyst formulations with platinum were found to be the most suitable for this one-step hydrogenation. Both the chemo-and the stereoselectivity of that reaction depend on the amount of base added and other parameters such as kind of solvent and/or support.