US4284816A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of preparing polyaminopolyphenylmethanes
Assignee: Huntsman Corp
•
Filing: 1980-09-17
•
Granted: 1981-08-18
•
Expires: 2000-09-17
Abstract
Abstract Covers a method of preparing diaminodiphenylmethanes and higher homologues thereof which comprises the step of condensing aniline and formaldehyde in the presence of a tungsten silicide catalyst.
Inventors
- 👤 Edward T. Marquis
- 👤 Lewis W. Watts, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:53
CPC Classifications
B; B01; B01J; B01J23/00; B01J23/16; B01J23/24; B01J23/30; C; C07; C07C; C07C209/00; C07C209/60
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
26 words
A method of preparing diaminodiphenylmethane and higher homologues thereof which comprises the step of condensing aniline and formaldehyde in the presence of a tungsten silicide catalyst.
Claim 2
Independent Claim
26 words
A method of preparing diaminodiphenylmethane and higher homologues thereof which comprises the step of condensing aniline and formaldehyde in the presence of a tungsten silicide catalyst.
Claim 3
Dependent Claim
30 words
The method of claim 1 wherein said catalyst is present in an amount ranging from about 0.5 to about 3.0 percent by weight based on the weight of aniline present.
Claim 4
Dependent Claim
17 words
The method of claim 2 wherein said catalyst present in an amount of 1-2 percent by weight.
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) | 1984-08-17 | 1985-02-16 | 1985-08-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-08-17 | 1989-02-16 | 1989-08-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-08-17 | 1993-02-16 | 1993-08-18 | $7700.00 | Window Closed / Lapsed |