Synthesis of Large-Pore Periodic Mesoporous Organosilicas Using Hexane as Swelling Agent

Large-pore organosilicas with methylene and ethylene bridges in the framework were synthesized at low initial temperature (15 degrees C) using hexane as a swelling agent and Pluronic P123 (EO20PO70EO20) block copolymers as template. Organosilica materials with the nominal (KJS) pore sizes of 18 and 10 nm were obtained in case of methylene and ethylene bridges, respectively. The variation of amount of precursor was found to have almost negligible effect on the interplanar spacing and pore size. The use of swelling agents with different chain length allowed us to tailor the pore size from 9 to 11 nm in case of ethylene-bridged organosilicas, when the first step of the synthesis was carried out at room temperature.