Zeolite synthesis with a fluoride source
Provided are a novel synthesis technique for producing pure phase aluminosilicate zeolite and a catalyst comprising the phase pure zeolite in combination with a metal, and methods of using the same. The pure phase aluminosilicate zeolite can be selected from those having an ITW framework and a silica to alumina ratio of less than about 140 or, an STW framework and a silica to alumina ratio less than about 100.
1. An aluminosilicate zeolite comprising:
(a) at least about 90% phase pure ITW framework and a silica-to-alumina ratio of less than about 140; or
(b) at least about 90% phase pure STW framework and a silica-to-alumina ratio of less than about 100;
wherein the aluminosilicate zeolite has a mean crystal size of about 0.5 μm to about 5 μm.
2. The aluminosilicate zeolite of claim 1 , wherein when the zeolite comprises an ITW framework, the aluminosilicate zeolite has a silica-to-alumina ratio of about 60 to about 140.
3. The aluminosilicate zeolite of claim 1 , wherein when the zeolite comprises an STW framework, the aluminosilicate zeolite has a silica-to-alumina ratio of less than about 100.
4. The aluminosilicate zeolite of claim 3 , wherein the aluminosilicate zeolite has a silica-to-alumina ratio of about 80 to about 100.
5. The aluminosilicate zeolite of claim 1 , wherein the aluminosilicate zeolite is substantially free of alkaline metal.
6. A catalyst article comprising an aluminosilicate zeolite of claim 1 , supported on or contained in a substrate selected from a wall-flow honeycomb filter and a flow-through honeycomb substrate.