Reductive Ullmann Coupling of Aryl Halides by Palladium Nanoparticles Supported on Cellulose, a Recoverable Heterogeneous Catalyst

Palladium nanoparticles supported on cellulose were prepared without using any reducing agent and used as a highly efficient catalyst for the Ullmann reductive coupling of aryl halides in the presence of zinc, in a water-alcohol mixture as solvent in air. The obtained palladium nanoparticles were characterized by scanning electron microscopy (SEM), FTIR, thermogravimetric analysis (TGA) and ICP-AES analysis. The synthesis of biaryls from chloroarenes was performed by this catalyst with good yield. The catalyst remains stable up to 75 degrees C and can be recovered and reused several times without loss of activity.