Patent US3253031A successfully refreshed from Google Patents.
US3253031A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for the preparation of crude diphenyl methane diamine
Assignee: Bayer Corp
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Filing: 1962-08-16
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Granted: 1966-05-24
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Expires: 1982-08-16
Abstract
No abstract record available.
Inventors
- 👤 Eugene L Powers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:37
CPC Classifications
C; C07; C07C; C07C209/00; C07C209/68; C07C209/78; C07C209/30; C07C209/32; C07C209/36; C07C209/82; C07C209/84; C07C211/00; C07C211/43; C07C211/44; C07C211/45; C07C211/46; C07C211/49; C07C211/50
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
104 words
A METHOD FOR THE PREPARATION OF AMINES WHICH COMPRISES CONTACTING FORMALDEHYDE WITH AN AMINE OF THE GENERAL FORMULA R-(NH2)X WHEREIN R IS A MONOCYCLIC AROMATIC RADICAL AND X IS AN INTEGER HAVING A VALUE OF 1 TO 4, IN THE PRESENCE OF AN ACID, THEREBY FORMING AN ACIDIC REACTION MIXTURE, NEUTRALIZING SAID ACIDIC REACTION MIXTURE WITH A BASE, DISTILLING THE NEUTRALIZED PRODUCT WHEREBY AN EXCESS OF THE INITIAL AMINE IS REMOVED, PRECIPITATING SALTS OF NEUTRALIZATION BY SAID DISTILLATION STEP, THEREBY RENDERING THE SALTS OF NEUTRALIZATION INSOLUBLE IN SAID RESULTING NEUTRALIZED PRODUCT, AND THEREAFTER REMOVING SAID PRECIPITATED SALTS FROM SAID RESULTING NEUTRALIZED PRODUCT BY FILTRATION.
Claim 2
Independent Claim
104 words
A METHOD FOR THE PREPARATION OF AMINES WHICH COMPRISES CONTACTING FORMALDEHYDE WITH AN AMINE OF THE GENERAL FORMULA R-(NH2)X WHEREIN R IS A MONOCYCLIC AROMATIC RADICAL AND X IS AN INTEGER HAVING A VALUE OF 1 TO 4, IN THE PRESENCE OF AN ACID, THEREBY FORMING AN ACIDIC REACTION MIXTURE, NEUTRALIZING SAID ACIDIC REACTION MIXTURE WITH A BASE, DISTILLING THE NEUTRALIZED PRODUCT WHEREBY AN EXCESS OF THE INITIAL AMINE IS REMOVED, PRECIPITATING SALTS OF NEUTRALIZATION BY SAID DISTILLATION STEP, THEREBY RENDERING THE SALTS OF NEUTRALIZATION INSOLUBLE IN SAID RESULTING NEUTRALIZED PRODUCT, AND THEREAFTER REMOVING SAID PRECIPITATED SALTS FROM SAID RESULTING NEUTRALIZED PRODUCT BY FILTRATION.
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) | 1969-05-23 | 1969-11-22 | 1970-05-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-05-23 | 1973-11-22 | 1974-05-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-05-23 | 1977-11-22 | 1978-05-24 | $7700.00 | Window Closed / Lapsed |