Synthesis, Characterization, and Catalytic Properties of Two Zwitterionic Hybrid SBA-15 Mesoporous Silicas

Zwitterionic hybrid SBA-15 mesoporous silica materials containing both amine and sulfonic acid groups have been synthesized through cocondensation from as-synthesized zwitterionic siloxane precursors (ZS) with tetraethoxysilane (TEOS). Characterization by XRD, TEM, and N2 adsorptiondesorption measurements show that the as-synthesized materials have ordered mesostructures. Analysis with UV, 29Si/13C cross-polarization magic angle spinning (CP-MAS) NMR, and X-ray photelectron spectroscopy (XPS) and elemental analysis demonstrates that the zwitterionic parts have been successfully introduced into the silica framework, and the organic contents of 15?% hybrid samples are over 1.0 mmol/g. The presence of a secondary organoamine group enables the hybrid material to be further alkalized to achieve the desired basic properties. The materials were used as catalysts for the aldol condensation of acetone with 4-nitrobenzaldehyde. With a good catalytic performance, the catalyst could be easily separated, recycled, and reactivated by secondary basification.