US2973371A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Phthalic anhydride catalysts of high surface area
Assignee: Wyeth Holdings LLC
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Filing: 1957-11-20
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Granted: 1961-02-28
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Expires: 1977-11-20
Abstract
No abstract record available.
Inventors
- 👤 Chomitz Nicholas
- 👤 William R Rathjens
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 00:31
CPC Classifications
C; C07; C07D; C07D307/00; C07D307/77; C07D307/87; C07D307/89; B; B01; B01J; B01J23/00; B01J23/16; B01J23/20; B01J23/22
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
79 words
A CATALYST FOR THE VAPOR PHASE FLUID BED CATALYTIC OXIDATION OF NAPHTHALENE TO PHTHALIC ANHYDRIDE COMPRISING ABOUT 5-20% BY WEIGHT OF VANADIUM OXIDE AND 20-50% OF A POTASSIUM SULFATE SUPPORTED ON ABOUT 40-75% OF A SILICA GEL CARRIER HAVING A SURFACE AREA WITHIN THE RANGE OF ABOUT 200-700 SQUARE METERS PER GRAM AND A PORE DIAMETER OF FROM 50 TO ABOUT 350 ANGSTROMS, SAID CATALYST HAVING A SURFACE AREA OF FROM 20 TO ABOUT 75 SQUARE METERS PER GRAM.
Claim 2
Dependent Claim
79 words
A CATALYST FOR THE VAPOR PHASE FLUID BED CATALYTIC OXIDATION OF NAPHTHALENE TO PHTHALIC ANHYDRIDE COMPRISING ABOUT 5-20% BY WEIGHT OF VANADIUM OXIDE AND 20-50% OF A POTASSIUM SULFATE SUPPORTED ON ABOUT 40-75% OF A SILICA GEL CARRIER HAVING A SURFACE AREA WITHIN THE RANGE OF ABOUT 200-700 SQUARE METERS PER GRAM AND A PORE DIAMETER OF FROM 50 TO ABOUT 350 ANGSTROMS, SAID CATALYST HAVING A SURFACE AREA OF FROM 20 TO ABOUT 75 SQUARE METERS PER GRAM.
Claim 3
Independent Claim
100 words
A METHOD OF PRODUCING PHTHALIC ANHYDRIDE WHICH COMPRISES PASSING A MIXTURE OF NAPHTHALENE VAPOR AND AIR IN CONTACT WITH A FLUIDIZED CATALYST BED MAINTAINED AT A TEMPERATURE WITHIN THE RANGE OF ABOUT 325*-425*C. AND CONTAINING A CATALYST COMPRISING ABOUT 5-20% BY WEIGHT OF VANADIUM OXIDE AND 20-Z50% OF POTASSIUM PYROSULFATE SUPPORTED ON ABOUT 40-75% OF A SILICA GEL CARRIER HAVING A SURFACE AREA WITHIN THE RANGE OF ABOUT 200-700 SQUARE METERS PER GRAM AND A PORE DIAMETER OF FROM 50 TO ABOUT 350 ANGSTROMS, SAID CATALYST HAVING A SURFACE AREA OF FROM 20 TO ABOUT 75 SQUARE METERS PER GRAM.
Claim 4
Independent Claim
100 words
A METHOD OF PRODUCING PHTHALIC ANHYDRIDE WHICH COMPRISES PASSING A MIXTURE OF NAPHTHALENE VAPOR AND AIR IN CONTACT WITH A FLUIDIZED CATALYST BED MAINTAINED AT A TEMPERATURE WITHIN THE RANGE OF ABOUT 325*-425*C. AND CONTAINING A CATALYST COMPRISING ABOUT 5-20% BY WEIGHT OF VANADIUM OXIDE AND 20-Z50% OF POTASSIUM PYROSULFATE SUPPORTED ON ABOUT 40-75% OF A SILICA GEL CARRIER HAVING A SURFACE AREA WITHIN THE RANGE OF ABOUT 200-700 SQUARE METERS PER GRAM AND A PORE DIAMETER OF FROM 50 TO ABOUT 350 ANGSTROMS, SAID CATALYST HAVING A SURFACE AREA OF FROM 20 TO ABOUT 75 SQUARE METERS PER GRAM.
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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) | 1964-02-28 | 1964-08-29 | 1965-02-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-02-28 | 1968-08-29 | 1969-02-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-02-28 | 1972-08-29 | 1973-02-28 | $7700.00 | Window Closed / Lapsed |