Structure-Direction Issues in the Fluoride Route to Pure-Silica Zeolites

9 Structure-Direction Issues in the Fluoride Route to Pure-Silica Zeolites 

However, there are at least two additional important structure-direction factors interplaying with that of fluoride in the synthesis of pure-silica zeolites by the fluoride route the OSDA and the degree of dilution of the synthesis gel. Villaescusa and Camblor have shown that the general concepts outlined above regarding structure-direction by OSD As can be successfully used in the search for new pure-silica materials, as shown for instance by the synthesis strategies that finally lead to the three-dimensional large pore zeolite ITQ-7. Nonetheless, we would like to point out at least one peculiarity, in this respect, of the fluoride route small cations may show by this route a rather specific structure-direction effect (like 1,3,5-trimethylimidazolium, which has a (C- -N)/N ratio of 8 but shows a rather large specificity towards zeolite ITQ-12 in fluoride aqueous medium). 

Be that as it may, Villaescusa s rule allowed Camblor s group to produce several new low density pure-silica materials, including lTQ-3, ITQ-4,t ITQ-7,t and ITQ-13,P as well 

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