Synthesis, characterization, and application of Cu2O and NiO nanoparticles supported on natural nanozeolite clinoptilolite as a heterogeneous catalyst for the synthesis of pyrano[3,2-b]pyrans and pyrano[3,2-c]pyridones

In this research, Cu2O and NiO nanoparticles supported on natural nanozeolite clinoptilolite (CP) was found to be a recoverable catalyst system for synthesis of pyrano-[3,2-c]pyridone and pyrano[3,2-b]pyran derivatives in aqueous media. The nanocatalysts were characterized by various techniques such as XRD, BET, SEM, TEM, TEM-EDS, and XPS analyses. TEM study reveals that the Cu2O and NiO nanoparticles have particle size less than 10 nm. XRD and XPS characterizations show the existence of forms of Cu2O or NiO on the surface of natural nanozeolite CP. The easy recovery of the catalyst and high yield of the products make the protocol attractive and economic. Furthermore, the nanocatalysts could be recycled and reused several times without significant loss in their catalytic activities.