Zinc Oxide Nanoparticles Supported on Modified Nano Clinoptilolite as a Novel Heterogeneous Nano Catalyst for Green Synthesis of Chromenopyrimidines

This study presents the synthesis of a novel and environmentally friendly nanocatalyst, NCP@SiO₃PrHMTAPrSiO₃ZnO, through the reaction of functionalized nanoclinoptilolite (CNP) with zinc oxide nanoparticles. Thermal gravimetric analysis (TGA), Fourier transform infrared (FTIR), and Raman spectroscopy results reveal the thermal stability and presence of the desired functional groups on the surface of NCP. The EDS and EDS mapping analyses confirm the existence of the Zn, O, N, C, Si, and Al elements in the structure of the synthetic NCP@SiO₃PrHMTAPrSiO₃ZnO. Furthermore, transmission electron microscopy (TEM) and SEM images of NCP@SiO₃PrHMTAPrSiO₃ZnO demonstrate that ZnO nanoparticles have a spherical shape (with an average size of 22 nm), while NCP has a layered-shaped morphology, with an average size of 58 nm. According to the turnover number (TON) and turnover frequency (TOF) results, synthetic NCP@SiO₃PrHMTAPrSiO₃ZnO exhibits superior catalytic efficiency in the one-pot multicomponent synthesis of chromenopyrimidine derivatives under solvent-free conditions. The suggested approach offers numerous benefits, including flawless cyclization, simple process, high product yields, quick reaction times, eco-friendly solvent use, and facile catalyst separation and recycling. Nevertheless, the recycled catalyst showed unchanged behavior after repeated characterization, confirming the material's integrity.