US5389357A
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US
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Modified crystalline aluminosilicate zeolites and process for their preparation
Assignee: JGC Catalysts and Chemicals Ltd
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Filing: 1994-06-01
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Granted: 1995-02-14
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Expires: 2014-06-01
Abstract
Abstract A process for the manufacture of a modified aluminosilicate zeolite is disclosed which includes contacting a starting zeolite in an aqueous phase with a dealuminating agent at a pH value of lower than 4 in the presence of a soluble silica. A novel zeolite composition is also disclosed which has increased acid and thermal stability.
Inventors
- 👤 Goro Sato
- 👤 Yusaku Arima
- 👤 Takanori Ida
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 09:59
CPC Classifications
C; C01; C01B; C01B39/00; C01B39/02; C01B39/026; Y; Y10; Y10S; Y10S423/00; Y10S423/21
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
170 words
A process for the manufacture of a modified crystalline aluminosilicate zeolite which comprises the steps of: (a) contacting a starting faujasite crystalline aluminosilicate zeolite having a crystalline lattice with a silica/alumina mole ratio of not more than 6 and a unit cell size of 24.65 Å or greater in an aqueous phase with a dealuminating agent selected from the group consisting of sulfuric acid, nitric acid and hydrochloric acid at a pH value not exceeding 4 in the presence of a soluble silica in an amount of not less than 500 ppm, said soluble silica being derived from a soluble silica source selected from the group consisting of silicic acid, metasilicate, orthosilicate, disilicate, trisilicate and silica sol; and (b) recovering a modified faujasite crystalline aluminosilicate zeolite wherein a portion of the aluminum from the zeolite crystal structure has been replaced with silicon, such that the recovered zeolite has a silica/alumina mole ratio of more than 6 and a crystallinity of at least 70% relative to that of said starting zeolite.
Claim 2
Dependent Claim
170 words
A process for the manufacture of a modified crystalline aluminosilicate zeolite which comprises the steps of: (a) contacting a starting faujasite crystalline aluminosilicate zeolite having a crystalline lattice with a silica/alumina mole ratio of not more than 6 and a unit cell size of 24.65 Å or greater in an aqueous phase with a dealuminating agent selected from the group consisting of sulfuric acid, nitric acid and hydrochloric acid at a pH value not exceeding 4 in the presence of a soluble silica in an amount of not less than 500 ppm, said soluble silica being derived from a soluble silica source selected from the group consisting of silicic acid, metasilicate, orthosilicate, disilicate, trisilicate and silica sol; and (b) recovering a modified faujasite crystalline aluminosilicate zeolite wherein a portion of the aluminum from the zeolite crystal structure has been replaced with silicon, such that the recovered zeolite has a silica/alumina mole ratio of more than 6 and a crystallinity of at least 70% relative to that of said starting zeolite.
Claim 3
Dependent Claim
40 words
A process according to claim 1 wherein said step (a) is effected by contacting said starting faujasite zeolite in said aqueous phase with said dealuminating agent at a pH value not exceeding 2 in the presence of said soluble silica.
Claim 4
Dependent Claim
68 words
A process according to claim 1 wherein said step (a) is effected by suspending said starting faujasite zeolite in said aqueous phase so as to maintain a mole ratio of SiO 2 to zeolite in the range of 0.01 to 0.30 and thereafter slowly adding said soluble silica in an amount of 0.01 to 2.0 mole of SiO 2 per mole of zeolite along with said dealuminating agent.
Claim 5
Dependent Claim
68 words
A process according to claim 2, wherein said step (a) is effected by suspending said starting faujasite zeolite in said aqueous phase so as to maintain a mole ratio of SiO 2 to zeolite in the range of 0.01 to 0.30 and thereafter slowly adding said soluble silica in an amount of 0.01 to 2.0 mole of SiO 2 per mole of zeolite along with said dealuminating agent.
Claim 6
Dependent Claim
31 words
A process according to claim 2 wherein said dealuminating agent is added at a rate of less than 0.2 moles per hour per mole of zeolite suspended in said aqueous phase.
Claim 7
Dependent Claim
16 words
A process according to claim 1 wherein said starting faujasite zeolite comprises an ammonium-sodium Y zeolite.
Claim 8
Dependent Claim
16 words
A process according to claim 1 wherein said starting faujasite zeolite comprises a sodium Y zeolite.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-02-13 | 1998-08-15 | 1999-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-02-13 | 2002-08-15 | 2003-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-02-13 | 2006-08-15 | 2007-02-14 | $7700.00 | Window Closed / Lapsed |