US3897314A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for removing distillation residue from crude isocyanates
Assignee: Bayer AG
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Filing: 1974-02-07
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Granted: 1975-07-29
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Expires: 1994-02-07
Abstract
Abstract A process is provided for separating residue from isocyanate concentrates produced by the phosgenation of organic amines. The isocyanate concentrate is passed under high vacuum through a system of downpipe evaporators and cyclone separators a portion of the liquid residue from the separator being recycled to the inlet of the evaporator along with the concentrate feed.
Inventors
- 👤 Dietrich Liebsch
- 👤 Dieter Becher
- 👤 Rudolf Kress
- 👤 Heinz Sauer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 20:40
CPC Classifications
C; C07; C07C; C07C263/00; C07C263/18; C07C263/20
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
142 words
A PROCESS FOR THE SINGLE STAGE CONTINUOUS SEPERATION OF RESIDUE FROM ISOCYANATE CONCENTRATES OBTAINED BY REACTING ALIPHATIC, CYCLOALIPHATIC, AROMATIC AND MIXED ALIPHATICAROMATIC AMINES WITH PHOSGENE COMPRISING EVAPORATING THE VOLATILE ISOCYANATE FROM THE CONCENTRATE IN A DOWNPIPE EVAPORATOR, THE PRESSURE AT OUTFLOW FROM SAID DOWNPIPE EVAPORATOR BEING BETWEEN 0.05 TO 50 MMHG, THE TEMPERATURE AT THE EXIT OF THE DOWNPIPE EVAPORATOR BEING BETWEEN 80* TO 250*C, RELEASING THE MIXTURE OF LIQUID AND VAPOR TO A SEPERATOR IN WHICH THE SAME TEMPERATURE AND PRESSURE CONDITIONS ARE MAINTAINED, SEPARATING THE LIQUID RESIDUE FROM THE VAPOR AND CONTINUOUSLY RETURNING A PORTION OF THE LIQUID RESIDUE TO THE INLET OF THE DOWNPIPE EVAPORATOR WHILE DISCHARGING THE REMAINER OF THE LIQUID RESIDUE FROM THE SYSTEM, THE QUANTITY OF THE LIQUID RESIDUE WHICH IS RETURNED CORRESPONDING TO ABOUT 2 TO ABOUT 100 TIMES THE QUANTITY OF ISOCYANATE CONCENTRATE FEED.
Claim 2
Dependent Claim
142 words
A PROCESS FOR THE SINGLE STAGE CONTINUOUS SEPERATION OF RESIDUE FROM ISOCYANATE CONCENTRATES OBTAINED BY REACTING ALIPHATIC, CYCLOALIPHATIC, AROMATIC AND MIXED ALIPHATICAROMATIC AMINES WITH PHOSGENE COMPRISING EVAPORATING THE VOLATILE ISOCYANATE FROM THE CONCENTRATE IN A DOWNPIPE EVAPORATOR, THE PRESSURE AT OUTFLOW FROM SAID DOWNPIPE EVAPORATOR BEING BETWEEN 0.05 TO 50 MMHG, THE TEMPERATURE AT THE EXIT OF THE DOWNPIPE EVAPORATOR BEING BETWEEN 80* TO 250*C, RELEASING THE MIXTURE OF LIQUID AND VAPOR TO A SEPERATOR IN WHICH THE SAME TEMPERATURE AND PRESSURE CONDITIONS ARE MAINTAINED, SEPARATING THE LIQUID RESIDUE FROM THE VAPOR AND CONTINUOUSLY RETURNING A PORTION OF THE LIQUID RESIDUE TO THE INLET OF THE DOWNPIPE EVAPORATOR WHILE DISCHARGING THE REMAINER OF THE LIQUID RESIDUE FROM THE SYSTEM, THE QUANTITY OF THE LIQUID RESIDUE WHICH IS RETURNED CORRESPONDING TO ABOUT 2 TO ABOUT 100 TIMES THE QUANTITY OF ISOCYANATE CONCENTRATE FEED.
Claim 3
Dependent Claim
47 words
The process of claim 1 wherein the downpipe evaporator is comprised of a plurality of vertically arranged downpipes having a diameter of from about 25 to about 60 mm and A length of up to about 3.5 m, said downpipes being surrounded by a common steam jacket.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-07-28 | 1979-01-27 | 1979-07-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-28 | 1983-01-27 | 1983-07-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-28 | 1987-01-27 | 1987-07-29 | $7700.00 | Window Closed / Lapsed |