US2587861A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation of benzidine sulfate
Assignee: EIDP Inc
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Filing: 1951-03-13
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Granted: 1952-03-04
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Expires: 1971-03-13
Abstract
No abstract record available.
Inventors
- 👤 William S Krause
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 20:37
CPC Classifications
C; C07; C07C; C07C211/00; C07C211/43; C07C211/54
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
91 words
A PROCESS FOR PREPARING BENZIDINE SULFATE FROM A RELATIVELY PURE BENZIDINE HYDROCHLORIDE WHICH COMPRISES TREATING A SOLUTION OF ONE PART OF BENZIDINE HYDROCHLORIDE IN 9 TO 15 PARTS OF WATER AT 60* TO 80* C. WITH SUFFICIENT SALT TO COMPLETELY PRECIPITATE THE BENZIDINE HYDROCHLORIDE, THEN WHILE MAINTAINING THE TEMPERATURE AT FROM 60* TO 80* C. ADDING FROM 2 TO 2.5 PARTS OF AN AQUEOUS SOLUTION OF SULFURIC ACID OF FROM 30% TO 40% CONCENTRATION WHICH CONTAINS DISSOLVED THEREIN FROM 0.1 TO 0.5 PART OF HYDROCHLORIC ACID PER PART OF SULFURIC ACID.
Claim 2
Dependent Claim
91 words
A PROCESS FOR PREPARING BENZIDINE SULFATE FROM A RELATIVELY PURE BENZIDINE HYDROCHLORIDE WHICH COMPRISES TREATING A SOLUTION OF ONE PART OF BENZIDINE HYDROCHLORIDE IN 9 TO 15 PARTS OF WATER AT 60* TO 80* C. WITH SUFFICIENT SALT TO COMPLETELY PRECIPITATE THE BENZIDINE HYDROCHLORIDE, THEN WHILE MAINTAINING THE TEMPERATURE AT FROM 60* TO 80* C. ADDING FROM 2 TO 2.5 PARTS OF AN AQUEOUS SOLUTION OF SULFURIC ACID OF FROM 30% TO 40% CONCENTRATION WHICH CONTAINS DISSOLVED THEREIN FROM 0.1 TO 0.5 PART OF HYDROCHLORIC ACID PER PART OF SULFURIC ACID.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1955-03-04 | 1955-09-03 | 1956-03-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1959-03-04 | 1959-09-03 | 1960-03-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1963-03-04 | 1963-09-03 | 1964-03-04 | $7700.00 | Window Closed / Lapsed |