Silicon substituted EMC-2 zeolite: LZ-281
AssigneeUop LLC
InventorsBen A. Wilson, Robert Lyle Patton, Vinayan Nair, Deng-Yang Jan, Hemant B. Gala
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Abstract
Applicants have prepared a novel zeolite identified as LZ-281. This zeolite has the framework topology of zeolite EMT. The LZ-281 zeolite is prepared by removing framework aluminum atoms from EMC-2 zeolite while simultaneously replacing the aluminum atoms with extraneous silicon atoms. This increases the SiO.sub.2 /Al.sub.2 O.sub.3 ratio versus the starting EMC-2 zeolite and results in the LZ-281 zeolite having increased thermal stability, increased number and/or strength of acid sites and increased activity in hydrocarbon processes requiring strong acid sites.
Claims2
A process for preparing a crystalline zeolitic aluminosilicate composition having at least some of its original framework aluminum atoms replaced by extraneous silicon atoms and having a mole ratio of oxides in the anhydrous state of
- aM.sub.2/n O:Al.sub.2 O.sub.3 :
- xSiO.sub.2
- where M is a cation of valence "n", "a" has a value of about 0.90.+-.0.2 and "x" has a value of greater than 11.2, the composition characterized in that it has the framework structure of EMT, a cation equivalency of at least 0.7 and an oxygen adsorption capacity of at least 70% of its theoretical capacity as measured at 100 torr and 90.degree. K, the process comprising contacting a crystalline EMC-2 zeolite having a SiO.sub.2 /Al.sub.2 O.sub.3 ratio of about 6.0 to about 10.0 with an aqueous solution of a fluorosilicate salt at a temperature of about 20.degree. C. to about 90.degree. C. for a time sufficient to remove at least some of the original framework aluminum and insert silicon into the framework, thereby forming said composition, the aqueous solution characterized in that it has a pH of about 3 to about 7 and contains fluorosilicate in an amount of at least 0.0075 moles of fluorosilicate per 100 grams of EMC-2 zeolite.
Dependencies are inferred from the claim text.