US4052456A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of preparing polyaminopolyphenylmethanes
Assignee: Huntsman Corp
•
Filing: 1977-01-31
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Granted: 1977-10-04
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Expires: 1997-01-31
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 an aluminum silicide catalyst.
Inventors
- 👤 Edward T. Marquis
- 👤 Lewis W. Watts, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 14:23
CPC Classifications
B; B01; B01J; B01J23/00; B01J23/16; B01J23/24; B01J23/30; C; C07; C07C; C07C209/00; C07C209/68; C07C209/78; C07C211/00; C07C211/43; C07C211/44; C07C211/49; C07C211/50
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 an aluminum 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 an aluminum 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)
US3676497A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-10-03 | 1981-04-04 | 1981-10-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-10-03 | 1985-04-04 | 1985-10-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-10-03 | 1989-04-04 | 1989-10-04 | $7700.00 | Window Closed / Lapsed |