Synthesis, characterization, and catalytic activity of sulfonic acid-functionalized periodic mesoporous organosilicas

Sulfonic acid-functionalized periodic mesoporous organosilicas were synthesized directly by cocondensation of (R′O)3Sisingle bondRsingle bondSi(OR′)3 (R = CH2CH2 and C6H4; R′ = CH3 and C2H5) with 3-mercaptopropyltrimethoxysilane (MeO)3SiCH2CH2CH2SH in the presence of H2O2 using nonionic oligomeric polymer surfactant C18H37(OCH2CH2)10OH in acidic medium. The sulfonic acid functionalities (single bondSO3H) were generated in situ by oxidation of the propylthiol using H2O2 as oxidant during the synthesis process. Powder X-ray diffraction patterns and nitrogen sorption indicate the formation of well-ordered mesoporous material with uniform porosity. The highest acid-exchange capacity (acid–base titration methods) was 1.72 H+ mmol/g. Complete oxidation of single bondSH to single bondSO3H was observed as evidenced by X-ray photoelectron spectroscopy. For comparison, the sulfonic acid-functionalized mesoporous organosilicas were also prepared by a grafting method. The catalytic properties of the materials were investigated in liquid-phase condensation of phenol with acetone to form Bisphenol A. All sulfonic acid-functionalized mesoporous organosilicas show high catalytic activity. The highest TOF obtained for the mesoporous organosilica is 17.2.