Metal-free chemoselective oxidation of sulfides to sulfoxides catalyzed by immobilized taurine and homotaurine in aqueous phase at room temperature

Natural products taurine and homotaurine were immobilized on the hybrid silica successfully and characterized by FT-IR, XPS, contact angle measurement, SEM, TGA, and XRD systematically. When the immobilized taurine (Tau@Si) and homotaurine (HTau@Si) were employed as heterogeneous catalysts in the oxidation of aromatic sulfides and aliphatic sulfides with 30% H2O2 at room temperature, up to 99.9% conversion and 98.0% selectivity were achieved with an excellent substrate tolerance. And the heterogeneous catalysts can be easily recycled up to 6 times without significant decrease in catalytic activity, which makes them promising catalysts for practical and large-scale applications in the oxidation of sulfides in aqueous phase at room temperature. (C) 2015 Elsevier Ltd. All rights reserved.