Molecular sieve SSZ-91, methods for preparing SSZ-91, and uses for SSZ-91
A family of new crystalline molecular sieves designated SSZ-91 is disclosed, as are methods for making SSZ-91 and uses for SSZ-91. Molecular sieve SSZ-91 is structurally similar to sieves falling within the ZSM-48 family of molecular sieves, and is characterized as: (1) having a low degree of faulting, (2) a low aspect ratio that inhibits hydrocracking as compared to conventional ZSM-48 materials having an aspect ratio of greater than 8, and (3) is substantially phase pure.
1. A molecular sieve comprising ZSM-48 type zeolite material, the molecular sieve having:
at least 70% polytype 6 of the total ZSM-48-type material;
an EUO-type phase in an amount of between 0 and 3.5 percent by weight; and
polycrystalline aggregate morphology comprising crystallites having an average aspect ratio of between 1 and 8.
2. The molecular sieve of claim 1 , wherein the molecular sieve has a silicon oxide to aluminum oxide mole ratio of 40 to 220.
3. The molecular sieve of claim 1 , wherein the molecular sieve has a silicon oxide to aluminum oxide mole ratio of 50 to 220.
4. The molecular sieve of claim 1 , wherein the molecular sieve comprises at least 80% polytype 6 of the total ZSM-48-type material.
5. The molecular sieve of claim 1 , wherein the molecular sieve comprises between 0.1 and 2 wt. % EU-1.
6. The molecular sieve of claim 1 , wherein the crystallites have an average aspect ratio of between 1 and 5.
7. The molecular sieve of claim 1 , wherein the molecular sieve comprises at least 90% polytype 6 of the total ZSM-48-type material.
8. The molecular sieve of claim 1 , wherein the crystallites have an average aspect ratio of between 1 and 3.