Structural characterization of organically-modified porous silicates synthesized using CTA(+) surfactant and acidic conditions

Organically-modified silicates have been synthesized from RSi(OEt)(3) (R=CH 3, C2H5, C8H17, CH2=CH or C6H5) and TEOS under acidic conditions, in the pr esence of cetyltrimethylammonium bromide (CTAB). The introduction of RSiO1. 5 units with R/Si=0.2:1, prevents the system from adopting a high degree of hexagonal mesostructural order, except when R=C6H5. or the sample containi ng the phenyl functionality, removal of the surfactant by calcination at 35 0 degrees C appears to be more complete, and less disruptive to mesoscopic ordering than solvent extraction using EtOH. Nitrogen adsorption measuremen ts on the hexagonally ordered calcined sample that still contains phenyl gr oups, yields a type I isotherm, typical of a microporous solid with a pore size distribution centered at 15 Angstrom.