Direct syntheses of ordered SBA-15 mesoporous silica containing sulfonic acid groups

A simple procedure has been developed for the syntheses of functionalized mesoporous materials with sulfonic groups involving the co-condensation of tetraethoxysilane and mercaptopropyltrimethoxysilane in the presence of block copolymers and hydrogen peroxide under acidic conditions. The modified SEA-15 materials show hexagonal mesoscopic order and pore sizes up to 60 Angstrom, with acid exchange capacities ranging from 1 to 2 mequiv of H+/g of SiO2, surface areas up to 800 m(2)/g, and excellent thermal and hydrothermal stabilities. The formation of the sulfonic groups during co-condensation of the silica species coincides with enhanced mesoscopic ordering and changes in the adsorption properties of the final materials. P-31 MAS NMR measurements of chemically adsorbed triethylphosphine oxide confirm the presence of Bronsted acid centers that are stronger that those found in Al-MCM-41. Finally, this procedure has been generalized to prepare functionalized mesoporous solids containing sulfonic groups and other organic moieties.