Patent US3620929A successfully refreshed from Google Patents.
US3620929A
Expired / Lapsed
US
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Process for separating ortho-isomers from tolyene diisocyanate mixtures
Assignee: Olin Corp
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Filing: 1968-10-31
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Granted: 1971-11-16
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Expires: 1988-10-31
Abstract
Abstract Removal of ortho-isomers from tolylene diisocyanate mixtures is effected by reacting said mixtures with a primary aromatic amine and subsequently distilling to recover nonvicinal tolylene diisocyanate.
Inventors
- 👤 Ehrenfried H Kober
- 👤 Wilhelm J Schnabel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:35
CPC Classifications
C; C07; C07D; C07D235/00; C07D235/02; C07D235/04; C07D235/24; C07D235/26; C07C; C07C263/00; C07C263/18; C07C263/20
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
13 words
The process of claim 1 wherein a mononuclear primary aromatic amine is employed.
Claim 2
Dependent Claim
15 words
The process of claim 2 wherein aniline is employed as the mononuclear primary aromatic amine.
Claim 3
Dependent Claim
16 words
The process of claim 2 wherein tolylene diamine is employed as the mononuclear primary aromatic amine.
Claim 4
Dependent Claim
23 words
The process of claim 1 wherein said mixture is heated at a temperature from about 100* to about 250* C. prior to distillation.
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) | 1974-11-15 | 1975-05-17 | 1975-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-15 | 1979-05-17 | 1979-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-15 | 1983-05-17 | 1983-11-16 | $7700.00 | Window Closed / Lapsed |