Nano Pd(0) supported on cellulose: A highly efficient and recyclable heterogeneous catalyst for the Suzuki coupling and aerobic oxidation of benzyl alcohols under liquid phase catalysis

Cellulose, a renewable bio-macromolecule has been used as a support material for the preparation of nano Pd(0) supported catalyst [Cell-Pd(0)], which exhibited high activity and selectivity for the Suzuki coupling in water; and oxidation of benzyl alcohols in acetonitrile under air atmosphere. Cell-Pd(0) could be recycled for several runs without loss of significant activity. Nano palladium(0) supported on cellulose was found to be highly efficient recyclable heterogeneous catalyst for the Suzuki coupling between aryl bromides and phenyl boronic acid in water and aerobic oxidation of benzyl alcohols using air as the source of molecular oxygen in acetonitrile. The Cell-Pd(0) was prepared by stirring commercially available cellulose with Pd(OAc)2 in ethanol at 25°C followed by reduction with hydrazine hydrate, leading finally to nano Pd(0) particles uniformly distributed on surface of cellulose. This catalytic system provides biaryls and polyaryls in excellent yields with very high turn over numbers via Suzuki coupling; and benzaldehyde derivatives in high yields and selectivity by oxidation in air. Cell-Pd(0) was characterized by X-ray diffraction techniques (XRD), thermal analysis (TGA), scanning electron microscope (SEM) and transmission electron microscope (TEM).