A novel one-step synthesis of mesostructured silica-pillared clay with highly ordered gallery organic–inorganic hybrid frame

Abstract

A new class of organic–inorganic hybrid mesostructured silica-pillared clay (HSPC) has been prepared through the surfactant directed assembly of organosilica in the galleries of montmorillonite. The surfactant templates were removed from the pores by solvent-extraction. The products were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), nitrogen adsorption–desorption measurements, solid-state 29Si and 13C NMR, and Fourier-transform infrared (FT-IR) spectra. XRD patterns indicated a regular interstratifications of the clay layers for HSPCs. Depending on loading of phenyl groups, HSPCs had BET surface areas of 395–602m2g−1, pore volumes of 0.34–0.79cm3g−1, and the framework pore sizes in the supermicropore to small mesopore range (1.3–2.6nm). HSPCs were hydrophobic and acidic. The number of silanol groups on the surface of HSPC materials has been titrated by a surface reaction with hexamethyldisilazane, followed by quantification of the liberated NH3. Based on this method extracted HPCHs have high silanol numbers, a very important feature with respect to the amount of catalytic sites that can eventually be grafted onto the surface.