Preparation and characterization of Fe3O4@SiO2@PMA:AS an efficient and recyclable nanocatalyst for the synthesis of 1-amidoalkyl-2-naphthols

Abstract In this paper, we report a method for preparation of functionalized superparamagnetic Fe 3 O 4 @SiO 2 that is synthesized based on several stages. First of all, the Fe 3 O 4 @SiO 2 nanosphere core-shell is synthesized. Then, H 3 PMo 12 O 40 nanoparticles were synthesized by the treatment of H 3 PMo 12 O 40 with n -Octane as solvent by a solvothermal method and this nano hetero polyacid immobilized onto the imidazole functionalized Fe 3 O 4 @SiO 2 nanoparticles. The structure of the samples was characterized by XRD, TEM, DLS, FE-SEM, FT-IR, N 2 adsorption–desorption isotherm analysis and VSM. Moreover, an efficient and direct protocol is described for the preparation of amidoalkyl naphthols employing a multi-component, one-pot condensation reaction of β-naphthol, aldehydes and acetamide, benzamide and urea in the presence of Fe 3 O 4 @SiO 2 -imid-PMA n under solvent-free and microwave conditions. Also, nanocatalyst can be easily recovered by a magnetic field and reused for the next reactions for at least 5 times without distinct deterioration in catalytic activity.