Synthesis of polyamides using palladium-on-carbon (Pd/C) as a heterogeneous, reusable and ligand-free catalytic system

This work reports the synthesis of polyamides using an efficient, ligand free and Pd/C-catalyzed protocol. Various polyamides can be synthesized by carbonylation polycondensation reaction of aromatic diiodides, diamines and carbon monoxide using Pd/C as a heterogeneous and recyclable catalyst. Variation in inherent viscosities observed with the structure of diamine component. Notably this synthetic route does not require any ligand and give high yield of the polyamides. Catalyst Pd/C can be recovered easily and was characterized using XPS analysis. The catalyst was recycled five times without substantial loss in activity.