US4377530A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Manufacture of isocyanates
Assignee: Wyeth Holdings LLC
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Filing: 1982-03-05
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Granted: 1983-03-22
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Expires: 2002-03-05
Abstract
Abstract A process for producing aromatic mono- and polyisocyanates by the addition reaction of isocyanic acid with vinyl aromatics is disclosed. The process is characterized by the slow addition of the olefin to a reaction mass of solvent and isocyanic acid to maintain the isocyanic acid in high excess to unreacted olefin.
Inventors
- 👤 Steven L. Trenbeath
- 👤 Allan M. Feldman
- 👤 Laurence J. Nummy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 08:27
CPC Classifications
C; C07; C07C; C07C263/00
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
113 words
In the preparation of isocyanates by addition of isocyanic acid to an olefin in an inert solvent and in the presence of a catalyst effective to promote the reaction, the improvement which comprises establishing a reaction mass of isocyanic acid and inert solvent therefor at approximately atmospheric pressure and at a temperature between about 25° and 80° C. and adding the olefin to the reaction mass at a rate such that the molar proportion of remaining isocyanic acid to unreacted olefin is above about 25 to 1, while maintaining said temperature between 25° and 80° C. and maintaining the molarity of unreacted isocyanic acid in said mass between about 1 and about 6.
Claim 2
Dependent Claim
113 words
In the preparation of isocyanates by addition of isocyanic acid to an olefin in an inert solvent and in the presence of a catalyst effective to promote the reaction, the improvement which comprises establishing a reaction mass of isocyanic acid and inert solvent therefor at approximately atmospheric pressure and at a temperature between about 25° and 80° C. and adding the olefin to the reaction mass at a rate such that the molar proportion of remaining isocyanic acid to unreacted olefin is above about 25 to 1, while maintaining said temperature between 25° and 80° C. and maintaining the molarity of unreacted isocyanic acid in said mass between about 1 and about 6.
Claim 3
Dependent Claim
13 words
The improvement according to claim 1 in which said olefin is a diisopropenylbenzene.
Claim 4
Dependent Claim
15 words
The improvement according to claim 1 or claim 2 in which said solvent is toluene.
Claim 5
Dependent Claim
16 words
The improvement according to claim 1 or claim 2 in which said solvent is methylene chloride.
Claim 6
Dependent Claim
15 words
The improvement according to claim 1 or claim 2 in which said solvent is chlorobenzene.
Claim 7
Dependent Claim
17 words
The improvement according to claim 1 or claim 2 in which said catalyst is dodecylbenzene sulfonic acid.
Claim 8
Dependent Claim
21 words
The improvement according to claim 1 or claim 2 in which said catalyst is selected from hydrogen chloride and hydrogen bromide.
References Cited (Backward Citations)
US3290350A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-03-21 | 1986-09-20 | 1987-03-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-03-21 | 1990-09-20 | 1991-03-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-03-21 | 1994-09-20 | 1995-03-22 | $7700.00 | Window Closed / Lapsed |