Synthesis of new silica-rich cubic and hexagonal faujasites using crown-etherbased supramolecules as templates

The direct synthesis of faujasite-type zeolites with a high framework Si/Al ratio has been the subject of a great deal of research work without achieving much success. Until now, no well crystallized faujasite-type zeolite with a framework Si/Al ratio higher than 3 could be obtained without a postsynthesis dealumination. By using organic templates of the crown-ether family, two pure and well-crystallized faujasite-type zeolites were synthesized with a framework Si/Al ratio approaching 5: (1) the cubic phase with 15-crown-5, and (2) the hexagonal phase with 18-crown-6.