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US4370260A
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Method of preparing supported platinum group metal catalysts
Assignee: WR Grace and Co Conn
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Filing: 1981-04-20
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Granted: 1983-01-25
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Expires: 2001-04-20
Abstract
Abstract A refractory inorganic oxide support is impregnated with a mixture which contains a platinum sulfito complex solution, a palladium sulfito complex solution, and a rhodium nitrate solution and has a pH of from about 1 to about 5. Activation of the impregnated support provides a three-way automotive exhaust catalyst having high efficiency and improved durability by a single impregnation method.
Inventors
- 👤 Gwan Kim
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 11:51
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/92; B01D53/94; B01D53/9445; B01D53/945; B01J; B01J23/00; B01J23/38; B01J23/40; B01J23/46; B01J23/464; B01J37/00; B01J37/02; B01J37/0201; Y; Y02; Y02A; Y02A50/00; Y02A50/20; Y02T; Y02T10/00; Y02T10/10; Y02T10/12
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
52 words
A method of preparing a platinum group metal catalyst composition comprising impregnating a refractory inorganic oxide support with a mixture having a pH from about 1 to about 5, said mixture comprising a platinum sulfito complex solution, a palladium sulfito complex solution, and a rhodium nitrate solution, and activating the impregnated support.
Claim 2
Independent Claim
52 words
A method of preparing a platinum group metal catalyst composition comprising impregnating a refractory inorganic oxide support with a mixture having a pH from about 1 to about 5, said mixture comprising a platinum sulfito complex solution, a palladium sulfito complex solution, and a rhodium nitrate solution, and activating the impregnated support.
Claim 3
Dependent Claim
16 words
The method of claim 1 in which the mixture further comprises a rhodium sulfito complex solution.
Claim 4
Dependent Claim
21 words
The method of claim 1 or 2 in which the mixture has a pH of from about 1 to about 4.
Claim 5
Dependent Claim
20 words
The method of claim 1 or 2 in which the mixture has a pH of from about 1.2 to 2.
Claim 6
Dependent Claim
21 words
The method of claim 1 or 2 in which the palladium sulfito complex solution is an acid complex in situ solution.
Claim 7
Dependent Claim
17 words
The method of claim 5 in which the palladium sulfito complex solution further comprises dibasic ammonium citrate.
Claim 8
Dependent Claim
21 words
The method of claim 1 or 2 in which the platinum sulfito complex solution is an acid complex in situ solution.
Claim 9
Dependent Claim
21 words
The method of claim 1 or 2 in which the platinum sulfito complex solution is an ammonium complex in situ solution.
Claim 10
Dependent Claim
26 words
The method of claim 1 or 2 in which the platinum sulfito complex contains from about 1 to about 4 sulfito groups per atom of platinum.
Claim 11
Dependent Claim
16 words
The method of claim 1 or 2 in which the support comprises shaped spheroidal alumina particles.
Claim 12
Dependent Claim
16 words
The method of claim 1 or 2 in which the support comprises shaped spheroidal ceria-alumina particles.
Claim 13
Dependent Claim
76 words
The method of claim 1 or 2 in which the platinum and palladium sulfito complexes are prepared by reacting a compound of platinum and a compound of palladium with a sulfiting agent in an amount of from about 1 to about 6 moles of SO 2 or HSO 3 - per gram atom of platinum and of from about 1 to about 6 moles of SO 2 or HSO 3 - per gram atom of palladium.
Claim 14
Dependent Claim
74 words
The method of claim 12 in which the platinum and palladium sulfito complexes are prepared by reacting a compound of platinum and a compound of palladium with a sulfiting agent in an amount of from about 3 to about 5 moles of SO 2 or HSO 3 - per gram atom of platinum and of from about 3 to about 5 moles of SO 2 or HSO 3 - per gram atom of palladium.
Claim 15
Dependent Claim
44 words
The method of claim 2 in which the amounts of rhodium nitrate solution and rhodium sulfito complex solution in the mixture are such that from about 30 to about 70 weight percent of the total rhodium in the mixture is provided by each solution.
Claim 16
Dependent Claim
44 words
The method of claim 2 in which the amounts of rhodium nitrate solution and rhodium sulfito complex solution in the mixture are such that from about 40 to about 60 weight percent of the total rhodium in the mixture is provided by each solution.
Claim 17
Dependent Claim
19 words
The method of claim 2 in which the rhodium sulfito complex solution is an acid complex in situ solution.
Claim 18
Dependent Claim
24 words
The method of claim 2 in which the rhodium sulfito complex contains from about 1 to about 3 sulfito groups per atom of rhodium.
Claim 19
Dependent Claim
33 words
The method of claim 2 in which the rhodium sulfito complex is prepared by reacting rhodium trichloride with sulfurous acid for about 1/2 to about 2 hours at about 40° to 80° C.
Claim 20
Dependent Claim
34 words
The method of claim 3 in which the rhodium sulfito complex is prepared by reacting rhodium trichloride with sulfurous acid for about 16 to about 24 hours at about 20° to about 30° C.
Claim 21
Independent Claim
90 words
A method of preparing an automotive exhaust catalyst composition comprising impregnating shaped spheroidal ceria-alumina particles with a mixture of an in situ platinum sulfito complex solution, an in situ palladium sulfito complex solution, a rhodium nitrate solution, and an in situ rhodium sulfito complex solution, said mixture having a pH of from about 1.2 to about 2 and containing sufficient amounts of each rhodium-containing solution so that each rhodium-containing solution provides from about 40 to about 60 percent of the total rhodium in the mixture, and activating the impregnated support.
Claim 22
Independent Claim
90 words
A method of preparing an automotive exhaust catalyst composition comprising impregnating shaped spheroidal ceria-alumina particles with a mixture of an in situ platinum sulfito complex solution, an in situ palladium sulfito complex solution, a rhodium nitrate solution, and an in situ rhodium sulfito complex solution, said mixture having a pH of from about 1.2 to about 2 and containing sufficient amounts of each rhodium-containing solution so that each rhodium-containing solution provides from about 40 to about 60 percent of the total rhodium in the mixture, and activating the impregnated support.
References Cited (Backward Citations)
US3932309A
Cited
US4154812A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-01-24 | 1986-07-26 | 1987-01-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-01-24 | 1990-07-26 | 1991-01-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-01-24 | 1994-07-26 | 1995-01-25 | $7700.00 | Window Closed / Lapsed |