High silica zeolites with three-dimensional systems of large pore channels

✍ Scribed by Miguel A. Camblor; Philip A. Barrett; Marı́a-José Dı́az-Cabañas; Luis A. Villaescusa; Marta Puche; Teresa Boix; Eva Pérez; Hubert Koller

• Publisher: Elsevier Science
• Year: 2001
• Tongue: English
• Weight: 239 KB
• Volume: 48
• Category: Article
• ISSN: 1387-1811
• DOI: 10.1016/s1387-1811(01)00325-0

✦ Synopsis

Several high silica zeolites with three-dimensional systems of large pore channels have been prepared in aqueous ¯uoride media: Beta, ITQ-7, ITQ-10 and ITQ-14. Pure silica beta can crystallize using up to 17 organic cations considerably dierent in size, shape, rigidity and C/N ratios. There are clear dierences in the powder X-ray diraction patterns of calcined beta materials prepared with dierent cations, suggesting structural dierences between them. However, this technique cannot be readily used to get further insights into these dierences. 19 F MAS NMR spectroscopy shows the existence of ¯uoride occluded in double four ring cages in most of the dierent betas, thus demonstrating for the ®rst time the real occurrence in these intergrown materials of polymorphs dierent from A and B. Double four ring cages are also present in ITQ-7 and in the new ITQ-10 and ITQ-14 zeolites.