Direct synthesis of vinyl-functionalized cubic mesoporous silica SBA-1

Abstract

Well-ordered cubic mesoporous silicas SBA-1 functionalized with vinyl groups have been synthesized via room temperature co-condensation of tetraethoxysilane (TEOS) and trimethoxyvinylsilane (TMVS) templated by cetyltriethylammonium bromide (CTEABr), a large headgroup surfactant, under strongly acidic conditions. The materials thus obtained were characterized by a variety of techniques including powder X-ray diffraction (XRD), solid-state NMR, FTIR, thermogravimetric analysis, scanning electron microscopy (SEM), and nitrogen sorption measurements. The HCl concentration was found to be a key factor that determines the stability of vinyl-functionalized SBA-1 towards the solvent extraction treatment. Direct evidence of the presence of chemically attached vinyl moieties was provided by solid-state 29Si and 13C NMR. SEM results revealed that the particle of vinyl-functionalized SBA-1 exhibited a highly isotropic morphology with more crystal faces than that of pure silica SBA-1. In contrast to the direct synthesis of vinyl-functionalized SBA-15, the concentration of TMVS that can co-condense with TEOS can be up to 25% without observing a significant loss in the long-range structure order and uncontrollable phase transformation of the cubic SBA-1 mesostructure.