Sulfonic Acid-Functionalized Silica-Coated Magnetic Nanoparticles as a Reusable Catalyst for the Preparation of Pyrrolidinone Derivatives Under Eco-Friendly Conditions

The surface of silica-coated CoFe2O4 magnetic nanoparticles (CoFe2O4@SiO2), which is resistant to the oxidation due to silicone coating, was functionalized using chlorosulfonic acid and used as an efficient and recyclable catalyst for the preparation of 3-pyrrolin-2-ones from diethyl acetylenedicarboxylate, an aldehyde and aniline in ethanol solvent at 60 °C. In the presented study, some fascinating chracteritics of such catalyst, such as magnetically separable, simple workup and obtaining a high purity of products by simple recrystallization, have been successfully obtained. The structural features of CoFe2O4@SiO2-SO3H catalyst were elucidated by X-ray powder diffraction (XRPD), thermo-gravimetric studying (TGA), scanning electron microscopy (SEM) and FT-IR spectra.