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

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 395-602 m2 g−1, pore volumes of 0.34-0.79 cm3g−1, and the framework pore sizes in the supermicropore to small mesopore range (1.3-2.6 nm). 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.

Research highlights▶ Organic-inorganic hybrid mesostructured silica-pillared clay (HSPC) has been prepared. ▶ The templates were removed by solvent extraction. ▶ The extracted materials have a high surface area and ordered gallery pore size. ▶ HSPCs were hydrophobic and acidic. ▶ The physical chemistry properties activate the HSPCs for application in catalysis, adsorption, separation chemistry and biochemistry.