Alkylation of Isobutane/1-Butene on Methyl-Modified Nafion/SBA-16 Materials

Three-dimensional mesoporous SBA-16 silica materials were functionalized with perfluorosulfonic acidic resin Nafion using an impregnation method. The intrinsic polarity of the SBA-16 surface was tuned by grafting ethoxytrimethylsilane on its surface. Characterized by N2-physisorption, X-ray diffraction (XRD), and transmission electron micrographs (TEM), all the materials synthesized exhibited ordered three-dimensional Im3m mesoporous structure. Elemental analysis and water adsorption measured by an intelligent gravimetric analyzer (IGA) showed that trimethylsilane is grafted on the surface by capping the −OHs which enhance the hydrophobicity of SBA-16. Elemental analysis and potentiometric titration showed that Nafion resin was incorporated, revealing a three-dimensional mesoporous strong solid acid with a hydrophobic surface. The catalytic alkylation of isobutane/1-butene was thereafter evaluated on each material under specified conditions and compared with the one-dimensional Nafion/SBA-15 and commercial Nafion silica nanocomposite SAC-13. The catalyst with three-dimensional mesoporous channels was shown to outperform the one with one-dimensional channels. The higher activity of Nafion over methyl modified SBA-16 materials is related to the more hydrophobic surface of support.