US2647124A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of preparing sulfuric acid half esters of leuco anthraquinones in mildly alkaline aqueous medium
Assignee: Wyeth Holdings LLC
•
Filing: 1950-07-24
•
Granted: 1953-07-28
•
Expires: 1970-07-24
Abstract
No abstract record available.
Inventors
- 👤 William B Hardy
- 👤 Elizaheth M Hardy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 23:37
CPC Classifications
C; C09; C09B; C09B9/00; C09B9/02
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
64 words
A PROCESS FOR THE MANUFACTURE OF WATERSOLUBLE, SULFURIC HALF ESTER SALTS OF LEUCO ANTHRAQUINONE COMPOUNDS, WHICH COMPRISES SUBJECTING THE ANTHRAQUINONE COMPOUND IN AN ALKALINE, AQUEOUS MEDIUM, HAVING A PH NOT GREATER THAN 11.5, TO SIMULATANEOUS REDUCTION WITH A REDUCING AGENT, AND ESTERIFICATION WITH A SULFUR TRIOXIDE ADDITION COMPOUND OF A TERTIARY AMINE, HAVING A DISSOCIATION OF CONSTANT OF AT LEAST 1X10-7 AT 25* C.
Claim 2
Dependent Claim
64 words
A PROCESS FOR THE MANUFACTURE OF WATERSOLUBLE, SULFURIC HALF ESTER SALTS OF LEUCO ANTHRAQUINONE COMPOUNDS, WHICH COMPRISES SUBJECTING THE ANTHRAQUINONE COMPOUND IN AN ALKALINE, AQUEOUS MEDIUM, HAVING A PH NOT GREATER THAN 11.5, TO SIMULATANEOUS REDUCTION WITH A REDUCING AGENT, AND ESTERIFICATION WITH A SULFUR TRIOXIDE ADDITION COMPOUND OF A TERTIARY AMINE, HAVING A DISSOCIATION OF CONSTANT OF AT LEAST 1X10-7 AT 25* C.
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) | 1956-07-27 | 1957-01-26 | 1957-07-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1960-07-27 | 1961-01-26 | 1961-07-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1964-07-27 | 1965-01-26 | 1965-07-28 | $7700.00 | Window Closed / Lapsed |