Synthesis, characterization and catalytic activity of ordered macroporous silicas functionalized with organosulfur groups

Hybrid three-dimensionally ordered macroporous (3DOM) SiO2-SO3H materials with different S/Si ratio have been prepared by colloidal crystal templating method. The process involved preparation of 3DOM SiO2-SH materials by co-condensation of (3-mercaptopropyl)triethoxysilane and tetraethoxysilane via sol-gel transformation, and following oxidation of -SH group to -SO3H group by H2O2. Materials were characterized by scanning electron microscopy (SEM), Fourier transform infra-red spectrometer (FTIR), thermogravimetric analysis (TGA), and nitrogen adsorption measurement. SEM observation shows that the macropores are highly ordered with a typical surface-templated structure. The surface area of 3DOM SiO2-SH material is 25.1 m(2)/g and SiO2-SO3H material is 18.6 m(2)/g. Catalytic activity test shows that 3DOM SiO2-SO3H materials possess a high activity for the esterification of acetic acid and n-butanol, and the activity is increased with the amount of sulfur in the materials. This study provided significant results for developing new application of 3DOM materials. (C) 2007 Elsevier Ltd. All rights reserved.