Patent US990573A successfully refreshed from Google Patents.
Patent US2863879A successfully refreshed from Google Patents.
US2863879A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Heating
Assignee: —
•
Filing: —
•
Granted: 1958-12-09
•
Expires: 1975-12-09
Abstract
No abstract record available.
Inventors
No inventors recorded.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 16:44
CPC Classifications
B; B01; B01J; B01J23/00; B01J23/002; C; C07; C07C; C07C51/00; C07C51/16; C07C51/21; C07C51/255; C07C51/265; C07C63/00; C07C63/14; C07C63/15; C07C63/16; C07D; C07D307/00; C07D307/77; C07D307/87; C07D307/89
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
115 words
A METHOD OF PRODUCING PHTHALIC ANHYDRIDE WHICH COMPRISES PASSING A MIXTURE OF NAPHTHALENE VAPOR AND AN OXYGEN-CONTAINING GAS AT LINEAR VELOCITIES OF ABOUT 0.2-2 FEET PER SECOND THROUGH A BED OF FLUIDIZED CATALYST PARTICLES CONTAINING AS THE PRINCIPAL ACTIVE CATALYST A MIXTURE OF V2O4 AND V2O5 AT A TEMPEATURE WITHIN THE RANGE OF ABOUT 320*-420*C. AND A NAPHTHALENE-TOOXYGEN RATIO SUCH THAT UPON CONTINUED OPERATION OF THE RATIO OF V2O4 TO V2O5 IN THE CATALYST WOULD EXCEED 70:30 AND MAINTAINING SAID RATIO BETWEEN THE LIMITS OF 70:30 AND 20:80 BY CONTINUOUSLY WITHDRAWING CATALYST FROM SAID BED, CONTINUOUSLY PARTIALLY OXIDIZING IT TO A V2O4 TO V2O5 RATIO WITHIN SAID LIMITS AND RETURNING IT TO SAID CATALYST BED.
Claim 2
Independent Claim
115 words
A METHOD OF PRODUCING PHTHALIC ANHYDRIDE WHICH COMPRISES PASSING A MIXTURE OF NAPHTHALENE VAPOR AND AN OXYGEN-CONTAINING GAS AT LINEAR VELOCITIES OF ABOUT 0.2-2 FEET PER SECOND THROUGH A BED OF FLUIDIZED CATALYST PARTICLES CONTAINING AS THE PRINCIPAL ACTIVE CATALYST A MIXTURE OF V2O4 AND V2O5 AT A TEMPEATURE WITHIN THE RANGE OF ABOUT 320*-420*C. AND A NAPHTHALENE-TOOXYGEN RATIO SUCH THAT UPON CONTINUED OPERATION OF THE RATIO OF V2O4 TO V2O5 IN THE CATALYST WOULD EXCEED 70:30 AND MAINTAINING SAID RATIO BETWEEN THE LIMITS OF 70:30 AND 20:80 BY CONTINUOUSLY WITHDRAWING CATALYST FROM SAID BED, CONTINUOUSLY PARTIALLY OXIDIZING IT TO A V2O4 TO V2O5 RATIO WITHIN SAID LIMITS AND RETURNING IT TO SAID CATALYST BED.
References Cited (Backward Citations)
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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) | 1961-12-08 | 1962-06-09 | 1962-12-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-12-08 | 1966-06-09 | 1966-12-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-12-08 | 1970-06-09 | 1970-12-09 | $7700.00 | Window Closed / Lapsed |