Effect of auxiliary chemicals on preparation of silica MCM-41

Silica MCM-41 materials were prepared hydrothermally by using 1,3,5-trimethylbenzene (MS) or 1,3,5-triisopropylbenzene (TI) as an auxiliary chemical. The BJH poressize of MCM-41 increased up to 12 nm with increasing amounts of MS. However, MCM-41 materials prepared with MS displayed irregular pore arrangements and a half of these materials exhibited low thermal and hydrothermal stabilities. On the other hand, MCM-41 materials prepared with TI as an auxiliary chemical displayed regular pore arrangements and high thermal and hydrothermal stabilities, but their BJH pore sizes did not go over 4.0 nm (intrinsic value; ca. 5 nm). MCM-41 prepared with TI together with a small amount of MS (TI/MS/SiO₂=1.5/0.5/1) displayed regular pore arrangements and high thermal and hydrothermal stabilities. Its BJH pore size was 4.7 nm (intrinsic value; ca. 6 nm).