US3928239A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for the production of exhaust and waste gases purifying catalysts
Assignee: Nippon Shokubai Co Ltd
•
Filing: 1973-11-29
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Granted: 1975-12-23
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Expires: 1993-11-29
Abstract
Abstract A catalyst used for the purification of exhaust gases from internal combustion engine and waste gases from industrial plants is produced by dissolving an alumina sol with an inorganic acid to form an alumina sol solution, adding thereto a powdered alumina which contains at least 50 % by weight of rho alumina and is capable of forming, upon calcination, an activated alumina to form an alumina slurry, immersing in the alumina slurry a monolithic multicellular chemically inert support, while maintaining said alumina slurry at 0* to 30*C, to deposit an alumina layer on to the surface of said support, aging the alumina layer at a temperature of 50*C or below for at least 30 minutes, drying the alumina layer to form a thin alumina film on the surface of the support, impregnating the so treated support in a noble metal containing solution and activating the so impregnated support.
Inventors
- 👤 Kiyoshi Yonehara
- 👤 Kunihiro Kubota
- 👤 Tetsuji Ono
- 👤 Takashi Ohara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 04:05
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/74; B01D53/86; B01D53/92; B01D53/94; B01D53/9404; B01D53/9409; B01D53/9413; B01J; B01J23/00; B01J23/38; B01J23/40; B01J35/00; B01J35/30; B01J35/34; B01J35/38; B01J35/391; B01J35/395; B01J35/80; B01D2251/00; B01D2251/20; B01D2251/202; B01D2251/21; B01D2255/00; B01D2255/10; B01D2255/102; B01J2235/00; B01J2235/15
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
194 words
A METHOD FOR THE PRODUCTION OF A CATALYST FOR PURIFICATION OF EXHAUST GASES OF INTERNAL COMBUSTION ENGINES AND WASTE GASES OF INDUSTRIAL PLANTS COMPRISING THE STEPS OF DISSOLVING AN ALUMINA SOL WITH AN INORGANIC ACID TO FORM AN ALUMINA SOL SOLUTION, ADDING TO THE SOLUTION A FINELY POWDERED ALUMINA CONTAINING AT LEAST 50% BY WEIGHT OF RHO-ALUMINA AND CAPABLE OF FORMING ACTIVATED ALUMINA ON CALCINATION TO FORM AN ALUMINA SLURRY, IMMERSING IN THE ALUMINA SLURRY A MONOLITHIC MULTICELLULAR CHEMICALLY INERT REFRACTORY SUPPORT, WHILE MAINTAINING SAID SLURRY AT A TEMPERATURE OF 0* TO 30*C, TO DEPOSIT A COATING FILM OF ALUMINA ON TO THE SURFACE OF SAID SUPORT, AGING THE IMMERSED SUPPORT AT A TEMPERATURE NOT EXCEESING 50*C FOR AT LEAST 30 MINUTES, DRYING SAID COATING FILM OF ALUMINA TO FORM A THIN UNIFORM FILM OF ALUMINA ON THE SURFACE OF SAID SUPPORT, IMPERGNATING THE SO TREATED SUPORT IN A SOLUTION OR SUSPENSION CONTAINING A MEMBER SELECTED FROM THE GROUP CONSISTING OF WATER SOLUBLE SALTS, METALLIC ACIDS AND METALLIC COLLOIDS OF A NOBLE METAL TO DEPOSIT A NOBLE METAL THEREON AND SUBJECTING THE BOBLE METAL-SUPORTING SUPPORT TO ACTIVATION AT A TEMPERATURE OF 150* TO 600*C.
Claim 2
Independent Claim
194 words
A METHOD FOR THE PRODUCTION OF A CATALYST FOR PURIFICATION OF EXHAUST GASES OF INTERNAL COMBUSTION ENGINES AND WASTE GASES OF INDUSTRIAL PLANTS COMPRISING THE STEPS OF DISSOLVING AN ALUMINA SOL WITH AN INORGANIC ACID TO FORM AN ALUMINA SOL SOLUTION, ADDING TO THE SOLUTION A FINELY POWDERED ALUMINA CONTAINING AT LEAST 50% BY WEIGHT OF RHO-ALUMINA AND CAPABLE OF FORMING ACTIVATED ALUMINA ON CALCINATION TO FORM AN ALUMINA SLURRY, IMMERSING IN THE ALUMINA SLURRY A MONOLITHIC MULTICELLULAR CHEMICALLY INERT REFRACTORY SUPPORT, WHILE MAINTAINING SAID SLURRY AT A TEMPERATURE OF 0* TO 30*C, TO DEPOSIT A COATING FILM OF ALUMINA ON TO THE SURFACE OF SAID SUPORT, AGING THE IMMERSED SUPPORT AT A TEMPERATURE NOT EXCEESING 50*C FOR AT LEAST 30 MINUTES, DRYING SAID COATING FILM OF ALUMINA TO FORM A THIN UNIFORM FILM OF ALUMINA ON THE SURFACE OF SAID SUPPORT, IMPERGNATING THE SO TREATED SUPORT IN A SOLUTION OR SUSPENSION CONTAINING A MEMBER SELECTED FROM THE GROUP CONSISTING OF WATER SOLUBLE SALTS, METALLIC ACIDS AND METALLIC COLLOIDS OF A NOBLE METAL TO DEPOSIT A NOBLE METAL THEREON AND SUBJECTING THE BOBLE METAL-SUPORTING SUPPORT TO ACTIVATION AT A TEMPERATURE OF 150* TO 600*C.
Claim 3
Dependent Claim
20 words
A method according to claim 1 in which the alumina sol solution is of a pH of 4.0 or below.
Claim 4
Dependent Claim
27 words
A method according to claim 1 in which the inorganic acid is at least one member selected from the group consisting of nitric acid and hydrochloric acid.
Claim 5
Dependent Claim
49 words
A method according to claim 1 in which the finely powdered alumina is of a weight accumulative average particle size of 25 microns or less and of a content of particles of sizes of 50 microns or less of at least 80% in the weight accumulative particle size distribution.
Claim 6
Dependent Claim
44 words
A method accordiong to claim 1 in which the alumina sol is amorpHous fibrous colloidal alumina in a concentration of 5 to 20% by weight, which dissolves when one acid selected from the group consisting of nitric acid and hydrochloric acid is added thereto.
Claim 7
Dependent Claim
35 words
A method according to claim 1 in which the alumina content which is originated from the alumina sol in the whole alumina which is contained in the alumina slurry is 5 to 50% by weight.
Claim 8
Dependent Claim
24 words
A method according to claim 1 in which an amount of the supported alumina is 30 to 300 g per litre of the support.
Claim 9
Dependent Claim
27 words
A method according to claim 1 in which an amount of the supported noble metal is 0.1 to 5 g as metal per litre of the support.
Claim 10
Dependent Claim
28 words
A method according to claim 8 in which the noble metal is at least one member selected from the group consisting of platinum, palladium, iridium, rhodium and ruthenium.
Claim 11
Dependent Claim
25 words
A method according to claim 8 in which the noble metal is at least one member selected from the group consisting of platinum and palladium.
Claim 12
Dependent Claim
29 words
A method according to claim 1 in which the activation is carried out by calcining the supported catalyst at a temperature of 300* to 600*C in an oxidative atmosphere.
Claim 13
Dependent Claim
26 words
A method according to claim 1 in which the activation is carried out by reducing at a temperature of 150* to 600*C in a reductive atmosphere.
Claim 14
Dependent Claim
22 words
A method according to claim 1 in which the noble metal containing solution is an aqueous solution of a noble metal compound.
Claim 15
Independent Claim
180 words
A method for the production of a catalyst for purification of exhaust gases of internal combustion engines and waste gases of industrial plants comprising the steps of: dissolving an alumina sol with an inorganic acid to form an alumina sol solution, adding to the solution a finely powdered alumina containing at least 50% by weight of rho-alumina and capable of forming activated alumina on calcination to form an alumina slurry, immersing in the alumina slurry a monolithic multicellular chemically inert refractory support, while maintaining said slurry at a temperature of 0* to 30*C, to deposit a coating film of alumina on to the surface of said support, aging the immersed support at a temperature not exceeding 50*C for at least 30 minutes, drying said coating film of alumina to form a thin uniform film of alumina on the surface of said support, calcining said treated support at a temperature of 300* to 600*C, impregnating the so treated support in a noble metal containing solution or suspension to deposit a noble metal thereon and subjecting the noble metal-supporting support to activation.
Claim 16
Independent Claim
180 words
A method for the production of a catalyst for purification of exhaust gases of internal combustion engines and waste gases of industrial plants comprising the steps of: dissolving an alumina sol with an inorganic acid to form an alumina sol solution, adding to the solution a finely powdered alumina containing at least 50% by weight of rho-alumina and capable of forming activated alumina on calcination to form an alumina slurry, immersing in the alumina slurry a monolithic multicellular chemically inert refractory support, while maintaining said slurry at a temperature of 0* to 30*C, to deposit a coating film of alumina on to the surface of said support, aging the immersed support at a temperature not exceeding 50*C for at least 30 minutes, drying said coating film of alumina to form a thin uniform film of alumina on the surface of said support, calcining said treated support at a temperature of 300* to 600*C, impregnating the so treated support in a noble metal containing solution or suspension to deposit a noble metal thereon and subjecting the noble metal-supporting support to activation.
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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) | 1978-12-22 | 1979-06-23 | 1979-12-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-22 | 1983-06-23 | 1983-12-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-22 | 1987-06-23 | 1987-12-23 | $7700.00 | Window Closed / Lapsed |