Platinum Metals Rev., 2001, 45, (1), 21
Heterogenised Rhodium Catalyst
The search for a clean benign replacement for the industrial synthesis of amines (N -phenyl-N ′-iso-propyl-p -phenylendiamine and N,N ′-di(1,4-dimethylpentyty-p phenylendiamine) used as antioxidants in vulcanising rubber, additives in biomimetic sensors and anticorrosive agents, has resulted in a one-pot synthesis using a platinum/carbon-based catalyst. However, this synthesis is not reproducible.
Now researchers at the Universitat Rovira i Virgili, Spain, have developed a reproducible one-pot synthesis to convert a primary amine into a secondary amine by imine intermediate formation (R. Margalef-Català, C. Claver, P. Salagre and E. Fernández, Tetrahedron Lett ., 2000, 41, (34), 6583-6588). The catalyst was prepared by immobilising preformed (Rh(COD)(PPh3)2]BF4 and its iridium analogue on montmorillonite K10. The rhodium catalyst had the higher activity. The reaction is mild and solvent-free and the catalyst can be easily recovered and reused.