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

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. (C) 2001 Elsevier Science B.V. All rights reserved.