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US3759916A
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Process for trimerizing polyisocyanates with pyrazine catalysts
Assignee: Olin Corp
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Filing: 1972-03-27
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Granted: 1973-09-18
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Expires: 1992-03-27
Abstract
Abstract A process for trimerizing organic polyisocyanates using selected pyrazine compounds as catalysts. The trimers produced are useful in the preparation of polyurethane resins.
Inventors
- 👤 J Pitts
- 👤 J Babiec
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 08:48
CPC Classifications
C; C07; C07D; C07D487/00; C07D487/02; C07D487/04; C08; C08G; C08G18/00; C08G18/06; C08G18/70; C08G18/72; C08G18/77; C08G18/78; C08G18/79; C08G18/791; Y; Y10; Y10S; Y10S521/00; Y10S521/902; Y10S528/00; Y10S528/902; Y10S528/906
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
27 words
The process of claim 1 wherein R is hydrogen and each of R1, R2, R3 and R4 is a lower alkyl having one to four carbon atoms.
Claim 2
Dependent Claim
32 words
The process of claim 2 wherein said catalyst is selected from the group consisting of 1,4,5,8-tetramethylhexahydropyrazino (2, 3-b) pyrazine; 1,4,5,8-tetraethylhexahydropyrazino (2,3-b) pyrazine; 1,4,5,8-tetrapropylhexahydropyrazino (2,3-b) pyrazine; 1,8-dimethyloctahydropyrazino (2,3-b) pyrazine; and 4,5-diethyloctahydropyrazino (2,3-b) pyrazine.
Claim 3
Dependent Claim
30 words
The process of claim 3 wherein said catalyst is employed in an amount of about 0.001 to about 5.0 percent by weight based on the weight of said organic polyisocyanate.
Claim 4
Dependent Claim
20 words
The process of claim 4 wherein said trimerization is carried out at a temperature from about -10* to about 200*C.
Claim 5
Dependent Claim
30 words
The process of claim 5 wherein said catalyst is employed in an amount of about 0.004 to about 3.5 percent by weight based on the weight of said organic polyisocyanate.
Claim 6
Dependent Claim
12 words
The process of claim 6 wherein said organic polyisocyanate is tolylene diisocyanate.
Claim 7
Dependent Claim
20 words
The process of claim 7 wherein said trimerization is carried out at a temperature of about 0* to about 80*C.
Claim 8
Dependent Claim
12 words
The process of claim 8 wherein said catalyst is 1,4,5,8-tetramethylhexahydropyrazino (2,3-b) pyrazine.
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) | 1976-09-17 | 1977-03-19 | 1977-09-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-09-17 | 1981-03-19 | 1981-09-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-09-17 | 1985-03-19 | 1985-09-18 | $7700.00 | Window Closed / Lapsed |