Patent US4359577A successfully refreshed from Google Patents.
US4359577A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Non-pyrophoric nigrosine base
Assignee: Wyeth Holdings LLC
•
Filing: 1980-04-04
•
Granted: 1982-11-16
•
Expires: 2000-04-04
Abstract
Abstract Nigrosine base (Color Index 50,415:1) which is pyrophoric is made non-pyrophoric by sparging a solution thereof in aniline with air.
Inventors
- 👤 Albrecht H. Granzow
- 👤 Erwin Klingsberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 17:10
CPC Classifications
C; C09; C09B; C09B17/00; C09B17/02
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
36 words
A method of preparing non-pyrophoric nigrosine base comprising aerating pyrophoric nigrosine base in aniline with an oxygen-containing gas at a temperature of about 20°-150° C. for a period of about 4 to 30 hours with agitation.
Claim 2
Independent Claim
36 words
A method of preparing non-pyrophoric nigrosine base comprising aerating pyrophoric nigrosine base in aniline with an oxygen-containing gas at a temperature of about 20°-150° C. for a period of about 4 to 30 hours with agitation.
Claim 3
Dependent Claim
31 words
The method of claim 1 wherein the gas is used at the rate of about one part by volume per minute per six parts by volume of nigrosine base in aniline.
Claim 4
Dependent Claim
12 words
The method of claim 1 wherein the temperature is about 50°-60° C.
Claim 5
Dependent Claim
14 words
The methods of claims 1, 2 or 3 wherein the oxygen-containing gas is air.
Claim 6
Dependent Claim
12 words
The product produced by the process of claims 1, 2 or 4.
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) | 1985-11-15 | 1986-05-17 | 1986-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-11-15 | 1990-05-17 | 1990-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-11-15 | 1994-05-17 | 1994-11-16 | $7700.00 | Window Closed / Lapsed |