Claims
- 1. A crystalline zeolite SN-beta having: 1) a three-dimensional microporous framework structure of SiO.sub.2 and AlO.sub.2 tetrahedral units; 2) an intracrystalline pore system; and 3) an empirical formula, on an anhydrous basis, expressed as the ratio of the oxides of:
- aM.sub.2/n O:Al.sub.2 O.sub.3 :bSiO.sub.2
- where "a" has a value from about zero to about 1.2, M is a cation having a valence of "n" and "b" has a value of about 30 to about 200, the zeolite characterized in that it has the crystal structure of zeolite beta and has absorbance maxima in the infrared region at 3780-3785 cm.sup.-1, 3745 cm.sup.-1 (shoulder), 3735 cm.sup.-1, 3675 cm.sup.-1, and 3610 cm.sup.-1, with the 3675 cm.sup.-1 absorbance being smaller than the 3610 cm.sup.-1 absorbance and has a surface area of at least 600 m.sup.2 /g.
- 2. The zeolite of claim 1 where "b" has a value from about 30 to about 80.
- 3. A process for preparing a crystalline zeolite SN-beta having: 1) a three-dimensional microporous framework structure of SiO.sub.2 and AlO.sub.2 tetrahedral units; 2) an intracrystalline pore system; and 3) an empirical formula, on an anhydrous basis, expressed as the ratio of the oxides of:
- aM.sub.2/n O:Al.sub.2 O.sub.3 :bSiO.sub.2
- where "a" has a value from about zero to about 1.2, M is a cation having a valence of "n" and "b" has a value of about 30 to about 200, the zeolite characterized in that it has the crystal structure of zeolite beta and has absorbance maxima in the infrared region at 3780-3785 cm.sup.-1, 3745 cm.sup.-1 (shoulder), 3735 cm.sup.-1, 3675 cm.sup.-1, and 3610 cm.sup.-1 with the 3675 cm.sup.-1 absorbance being smaller than the 3610 cm.sup.-1 absorbance and has a surface area of at least 600 m.sup.2 /g, the process comprising
- a) calcining an as-synthesized zeolite beta starting material at a temperature sufficient to decompose any organic cations contained in the intracrystalline pore system;
- b) heating the calcined product of step (a) in the presence of about 5 to about 100 percent steam at a temperature of about 500.degree. C. to about 800.degree. C. for a period of time sufficient to dealuminate and stabilize the zeolite.
- c) contacting the steamed product of step (b) with a sufficient amount of an aqueous solution of ammonium ions at a pH of about 1.0 to about 3.5 for a time sufficient to remove extraframework aluminum and provide said crystalline zeolite SN-beta.
- 4. The process of claim 3 where the calcination of step (a) is carried out at a temperature of about 540.degree. C. to about 650.degree. C.
- 5. The process of claim 3 where in step (b) the temperature is from about 550.degree. C. to about 700.degree. C.
Parent Case Info
This application is a continuation-in-part of prior copending application U.S. Application No. 08/292,665 filed on Aug. 18, 1994, now abandoned which is incorporated by reference.
US Referenced Citations (14)
Non-Patent Literature Citations (1)
Entry |
Kiricsi et al., "Progress toward Understanding Zeolite Beta Acidity: An IR and AI NMR Spectroscopic Study," J. Phys. Chem., vol. 98, pp. 4627-4634, 1994. |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
292665 |
Aug 1994 |
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