US3909456A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Catalyst for promoting reduction of nitrogen oxides contained in exhaust gases
Assignee: Nissan Motor Co Ltd
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Filing: 1973-04-12
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Granted: 1975-09-30
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Expires: 1993-04-12
Abstract
Abstract A catalyst for reducing nitrogen oxides contained in exhaust gases, comprising a major portion of a carrier, and 0.02 to 0.85 wt% of ruthenium. The catalyst may also contain platinum, rhodium and/or palladium. The catalyst is obtained by immersing the carrier in an aqueous solution containing a catalytic component or components, and calcining the same in a flow of hydrogen gas at 300* to 1,000*C.
Inventors
- 👤 Kiyoshi Numagami
- 👤 Toshiki Okuyama
- 👤 Tadanari Kato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 19:12
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/92; B01D53/94; B01D53/9404; B01D53/9409; B01D53/9413; B01J; B01J23/00; B01J23/38; B01J23/40; B01J23/46; B01J23/464; B01D2255/00; B01D2255/10; B01D2255/102; B01D2255/1021; B01D2255/1023; B01D2255/1025; B01D2255/1026
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
123 words
A METHOD FOR PREPARING A CATALYST FOR REDUCING NITROGEN OXIDES CONTAINED IN EXHAUST GASES, SAID METHOD COMPRISING THE STEPS FORMING A MONOLITHIC CARRIER IN A DESIRED FORM, IMMERSING SAID CARRIER IN AN AQUEOUS SOLUTION CONTAINING A RUTHENIUM SALT SO AS TO SUPPORT RUTHENIUM IN AN AMOUNT OF 0.020.85% BY WEIGHT, AND A SALT OF AT LEAST ONE METAL SELECTED FROM THE GROUP CONSISTING OF PALLADIUM, PLATIUM AND RHODIUM SO AS TO SUPPORT THE AT LEAST ONE METAL IN AN AMOUNT OF 0.001 TO 0.7% BY WEIGHT REMOVING THE IMMERSED CARRIER FROM THE SOLUTION, EXPOSING THE CARRIER TO A FLOW OF AMMONIA GAS, DRYING THE CARRIER, AND CALCINING THE RESULTANT CARRIER IN A FLOW OF HYDROGEN GAS AT A TEMPERATURE OF 300*C TO 1,000*C.
Claim 2
Independent Claim
123 words
A METHOD FOR PREPARING A CATALYST FOR REDUCING NITROGEN OXIDES CONTAINED IN EXHAUST GASES, SAID METHOD COMPRISING THE STEPS FORMING A MONOLITHIC CARRIER IN A DESIRED FORM, IMMERSING SAID CARRIER IN AN AQUEOUS SOLUTION CONTAINING A RUTHENIUM SALT SO AS TO SUPPORT RUTHENIUM IN AN AMOUNT OF 0.020.85% BY WEIGHT, AND A SALT OF AT LEAST ONE METAL SELECTED FROM THE GROUP CONSISTING OF PALLADIUM, PLATIUM AND RHODIUM SO AS TO SUPPORT THE AT LEAST ONE METAL IN AN AMOUNT OF 0.001 TO 0.7% BY WEIGHT REMOVING THE IMMERSED CARRIER FROM THE SOLUTION, EXPOSING THE CARRIER TO A FLOW OF AMMONIA GAS, DRYING THE CARRIER, AND CALCINING THE RESULTANT CARRIER IN A FLOW OF HYDROGEN GAS AT A TEMPERATURE OF 300*C TO 1,000*C.
Claim 3
Dependent Claim
15 words
A method as claimed in claim 1, wherein said ruthenium salt is ruthenium (III) chloride.
Claim 4
Dependent Claim
25 words
A method as claimed in claim 1, wherein said palladium saLt is selected from the group consisting of palladium (II) nitrate and palladium (II) chloride.
Claim 5
Dependent Claim
15 words
A method as claimed in claim 1, wherein said rhodium salt is rhodium (III) nitrate.
Claim 6
Independent Claim
110 words
A method for preparing a catalyst for reducing nitrogen oxides contained in exhaust gases, said method comprising the steps of: forming a monolithic carrier in a desired form; immersing said carrier in an aqueous solution containing a ruthenium salt so as to support ruthenium in an amount of 0.02 -0.85% by weight, and chloroplatinic acid so as to support the metal in said acid in an amount of 0.001 to 0.7% by weight; removing the immersed carrier from the solution; exposing the carrier to a flow of ammonia gas; drying the carrier; and calcining the resultant carrier in a flow of hydrogen gas at a temperature of 300*C to 1,000*C.
Claim 7
Independent Claim
110 words
A method for preparing a catalyst for reducing nitrogen oxides contained in exhaust gases, said method comprising the steps of: forming a monolithic carrier in a desired form; immersing said carrier in an aqueous solution containing a ruthenium salt so as to support ruthenium in an amount of 0.02 -0.85% by weight, and chloroplatinic acid so as to support the metal in said acid in an amount of 0.001 to 0.7% by weight; removing the immersed carrier from the solution; exposing the carrier to a flow of ammonia gas; drying the carrier; and calcining the resultant carrier in a flow of hydrogen gas at a temperature of 300*C to 1,000*C.
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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) | 1978-09-29 | 1979-03-31 | 1979-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-29 | 1983-03-31 | 1983-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-29 | 1987-03-31 | 1987-09-30 | $7700.00 | Window Closed / Lapsed |