Green Formylation of Alcohols Catalyzed by Magnetic Nanoparticles of the Core-Shell Fe3O4@SiO2-SO3H

The immobilized sulfonic acid on silica-layered magnetite was successfully synthesized and characterized using Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction spectroscopy, scanning electron microscopy and thermogravimetric analyses. The prepared Fe3O4@SiO2-SO3H MNPs were used as an efficient solid acidic nanocatalyst toward successful formylation of structurally diverse aliphatic and benzylic primary/secondary alcohols using formic acid under oil bath conditions (60 degrees C). The product, formyl esters, was obtained in 76-92% yields within 1-20min. The sulfonated nanocatalyst was easily recovered by an external magnetic field and reused for five consecutive cycles without significant loss of its catalytic activity. [GRAPHICS]