Résumé
The influence of organic concentration, Si/Al ratio, stirring and nature of the silica source on zeolite synthesis in the presence of tetraethylammonium have been studied. Examples of metastability of zeolite beta and ZSM-5 towards ZSM-12 propose the last as the more stable zeolitic phase in tetraethylammonium media featuring highest Si/Al ratio. Evidences of heterogeneous nucleation of zeolites over amorphous or crystalline phases are discussed.