Fe 3 O 4 @BNPs@SiO 2 -SO 3 H as a highly chemoselective heterogeneous magnetic nanocatalyst for the oxidation of sulfides to sulfoxides or sulfones.

To achieve green chemistry goals and also to reduce the cost of catalysts as well as to avoid producing toxic wastes and show the importance of separation and recycling of catalysts from the reaction medium, in this work, we describe the preparation and characterization of magnetic acidic boehmite nanoparticles as a heterogeneous catalyst, which is called Fe 3 O 4 @BNPs@SiO 2 -SO 3 H. This catalyst works efficiently in the selective oxidation of sulfides to sulfoxides or sulfones in the presence of H 2 O 2 as a green oxidant. It can easily be separated from the reaction medium by using an external magnet and it was recycled 6 times without loss of magnetic catalytic properties.