Zeolite synthesis with alkaline earth metal
Provided is a novel synthesis technique for producing pure phase small pore zeolites employing a synthesis gel of at least one zeolite, a structure directing agent and an alkaline earth metal source. Additionally provided are a novel form of AFX zeolite, a novel synthesis method for producing a zeolite with an increased Al pair content, a catalyst comprising the AFX zeolite in combination with a metal, and methods of using the same.
1. A method for making an aluminosilicate zeolite having a small pore framework comprising reacting a synthesis gel comprising at least one zeolite, a structure directing agent, an alkaline earth metal source, and an optional silica source at a temperature of at least about 100° C. until crystals of the small pore zeolite form.
2. The method of claim 1 , wherein the small pore zeolite crystals are at least about 90% phase pure.
3. The method of claim 1 , wherein the synthesis gel is substantially free of alkaline metal.
4. The method of claim 1 , wherein the synthesis gel has one or more of the following compositional molar ratios:
SiO 2 /Al 2 O 3 of about 10 to about 80;
Na 2 O/Al 2 O 3 of about 0 to about 2;
M AE O/Al 2 O 3 of about 0.3 to about 1.5 (M AE can be Ca, Sr, or Ba);
SDA 2 O/Al 2 O 3 of about 0.7 to about 20;
H 2 O/Al 2 O 3 of about 300 to about 3000; and
OH − /SiO 2 of about 0.25 to about 0.5.
5. The method of claim 1 , wherein the SDA cation is 1,3-bis(1-adamantyl)imidazolium, N,N-diethyl-cis 2,6-dimethylpiperidinium, N,N-dimethyl-3,5-dimethylpiperidinium, N,N,N-1-trimethyladamantylammonium, or N,N,N-dimethylethylcyclohexylammonium.