US3410888A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for recovering aromatic diisocyanates
Assignee: Pharmacia and Upjohn Co
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Filing: 1965-05-18
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Granted: 1968-11-12
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Expires: 1985-05-18
Abstract
No abstract record available.
Inventors
- 👤 Philip D Hammond
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 20:27
CPC Classifications
C; C07; C07C; C07C263/00; C07C263/18; C07C263/20
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
120 words
A PROCESS FOR THE RECOVERY OF AN AROMATIC DIISOCYANATE FROM A REACTION MASS RESIDUE WHEREIN SAID DIISOCYANATE CONTAINS TWO PHENYL NUCLEI AND THE ISOCYANATE GROUPS ARE ATTACHED TO NUCLEAR CARBON ATOMS IN DIFFERENT PHENYL NUCLEI, SAID PROCESS COMPRISING THE STEPS OF: (1) REACTING THE CORRESPONDING AROMATIC DIAMINE WITH PHOSGENE AND DISTILLING OFF A PORTION OF THE AROMATIC DIISOCYANATE SO PRODUCED, (2) PASSING THE REMAINING RESIDUE INTO A SECOND DISTILLATION VESSEL IN WHICH (A) THE RESIDUE IS DISTRIBUTED UPON THE INNER SURFACE OF SAID VESSEL AS A THIN FILM, AND (B) THE FILM IS SUBJECTED TO A TEMPERATURE AND VACUUM SUFFICIENT TO EVAPORATE THE AROMATIC DIISOCYANATE, AND (3) REMOVING AS VAPORS FROM SAID VESSEL, A VAPOR SUBSTANTIALLY RICH IN AROMATIC DIISOCYANATE.
Claim 2
Dependent Claim
120 words
A PROCESS FOR THE RECOVERY OF AN AROMATIC DIISOCYANATE FROM A REACTION MASS RESIDUE WHEREIN SAID DIISOCYANATE CONTAINS TWO PHENYL NUCLEI AND THE ISOCYANATE GROUPS ARE ATTACHED TO NUCLEAR CARBON ATOMS IN DIFFERENT PHENYL NUCLEI, SAID PROCESS COMPRISING THE STEPS OF: (1) REACTING THE CORRESPONDING AROMATIC DIAMINE WITH PHOSGENE AND DISTILLING OFF A PORTION OF THE AROMATIC DIISOCYANATE SO PRODUCED, (2) PASSING THE REMAINING RESIDUE INTO A SECOND DISTILLATION VESSEL IN WHICH (A) THE RESIDUE IS DISTRIBUTED UPON THE INNER SURFACE OF SAID VESSEL AS A THIN FILM, AND (B) THE FILM IS SUBJECTED TO A TEMPERATURE AND VACUUM SUFFICIENT TO EVAPORATE THE AROMATIC DIISOCYANATE, AND (3) REMOVING AS VAPORS FROM SAID VESSEL, A VAPOR SUBSTANTIALLY RICH IN AROMATIC DIISOCYANATE.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1971-11-12 | 1972-05-13 | 1972-11-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1975-11-12 | 1976-05-13 | 1976-11-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1979-11-12 | 1980-05-13 | 1980-11-12 | $7700.00 | Window Closed / Lapsed |