Immobilization of cerium (IV) and erbium (III) in mesoporous MCM‐41: Two novel and highly active heterogeneous catalysts for the synthesis of 5‐substituted tetrazoles, and chemo‐ and homoselective oxidation of sulfides

Two well‐ordered 2D‐hexagonal cerium (IV) and erbium (III) embedded functionalized mesoporous MCM‐41(MCM‐41@Serine/Ce and MCM‐41@Serine/Er) have been developed via functionalization of mesoporous MCM‐41. The surface modification method has been used in the preparation of serine‐grafted MCM‐41 and led to the development of MCM‐41@Serine. The reaction of MCM‐41@Serine with Ce (NH4)2(NO3)6·2H2O or ErCl3·6H2O in ethanol under reflux led to the organization of MCM‐41@Serine/Ce and MCM‐41@Serine/Er catalysts. The structures of these catalysts were determined using scanning electron microscopy, mapping, energy‐dispersive X‐ray spectroscopy, Fourier transform‐infrared, thermogravimetric analysis, X‐ray diffraction, inductively coupled plasma, and Brunauer–Emmett–Teller analysis. These MCM‐41@Serine/Ce and MCM‐41@Serine/Er catalysts show outstanding catalytic performance in sulfides oxidation and synthesis of 5‐substituted tetrazoles. These catalysts can be recycled for seven repeated reaction runs without showing a considerable decrease in catalytic performance. Highlights Two novel, and eco‐friendly MCM‐41@Serine/Ce and MCM‐41@Serine/Er catalysts were prepared and characterized. These catalysts can be used as an efficient and reusable mesostructured for the synthesis of 5‐substituted tetrazoles and oxidation of sulfides into sulfoxides. The products were obtained in high to excellent yields in a short reaction time. MCM‐41@Serine/Ce and MCM‐41@Serine/Er catalysts could be recovered easily and reused several consecutive cycles without a significant decrease in efficiency.