Patent US2509873A successfully refreshed from Google Patents.
US2509873A
Expired / Lapsed
US
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Dicarboxylic acid anhydride preparation
Assignee: Standard Oil Development Co
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Filing: 1946-01-18
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Granted: 1950-05-30
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Expires: 1966-01-18
Abstract
No abstract record available.
Inventors
- 👤 Mcateer James Howard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 19:05
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/54; C07C51/56
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
69 words
THE METHOD OF DEHYDRATING MALEIC ACID TO ITS ANHYDRIDE WHICH COMPRISES FORMING A REACTION MIXTURE OF MALEIC ACID WITH TOLUENE AND A SMALL CATALYTIC AMOUNT OF SULFURIC ACID, HEATING THE REACTION MIXTURE TO BOILING, CONTINUOUSLY DISTILLING FROM THE REACTION MIXTURE TOLUENE TOGETHER WITH WATER FORMED BY DEHYDRATION OF THE MALEIC ACID AT 80*C. TO 115*C., SEPARATING WATER DISTILLATE FROM TOLUENE DISTILLATE, AND RETURNING TOLUENE DISTILLATE TO THE REACTION MIXTURE.
Claim 2
Independent Claim
69 words
THE METHOD OF DEHYDRATING MALEIC ACID TO ITS ANHYDRIDE WHICH COMPRISES FORMING A REACTION MIXTURE OF MALEIC ACID WITH TOLUENE AND A SMALL CATALYTIC AMOUNT OF SULFURIC ACID, HEATING THE REACTION MIXTURE TO BOILING, CONTINUOUSLY DISTILLING FROM THE REACTION MIXTURE TOLUENE TOGETHER WITH WATER FORMED BY DEHYDRATION OF THE MALEIC ACID AT 80*C. TO 115*C., SEPARATING WATER DISTILLATE FROM TOLUENE DISTILLATE, AND RETURNING TOLUENE DISTILLATE TO THE REACTION MIXTURE.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1953-05-29 | 1953-11-28 | 1954-05-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1957-05-29 | 1957-11-28 | 1958-05-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1961-05-29 | 1961-11-28 | 1962-05-30 | $7700.00 | Window Closed / Lapsed |