In situ preparation of CeO2 nanoparticles on the MCM-41 with magnetic core as a novel and efficient catalyst for the synthesis of substituted pyran derivatives

An inexpensive, environmentally-benign, and magnetically recoverable nanocomposite consisting of magnetic core and MCM-41 mesoporous silica shell which was synthesized by using Rice Husk Ash (RHA) as the silica source was prepared. Subsequently, the CeO2 nanoparticles were synthesized and immobilized on the magnetically recoverable MCM-41 by impregnation method. The synthesized nanocomposite was characterized with FT-IR, XRD, FE-SEM, TEM, ICP and VSM. The obtained new nanocomposite demonstrated a catalytic performance in the synthesis of tetrahydrobenzo[b]pyrans at the condensation condition under solvent-free conditions. The nanocomposite catalyst could simply be recovered from the reaction environment by using an external magnet field and be reused five times without a remarkable losing in catalytic property.