SYNTHESES OF HIGHLY ORDERED MESOPOROUS MATERIALS, FSM-16, DERIVED FROM KANEMITE

The synthetic conditions of highly ordered and thermally stable mesopo rous molecular sieves from a layered silicate kanemite are established . We divided the formation process of the mesoporous materials from ka nemite into two elemental processes: i) exchange of Na+ in the interla yer of kanemite for alkyltrimethylammonium cations and ii) condensatio n of silicates and formation of a three dimensional silicate framework . Higher pH (over 11.5) at the cation-exchange process and the subsequ ent pH adjustment at 8.5 at the condensation process were best suited for the formation of mesoporous products with high regularity and ther mal stability. Removal of partially dissolved kanemite during the cati on-exchange process avoided the formation of amorphous materials as a by-product. Structures of some intermediate silicate/surfactant comple xes supported the proposed folded sheets mechanism for the formation o f the mesoporous molecular sieves. Syntheses by using alkyltrimethylam monium with different alkyl-chain lengths are also reported.