Patent US3717613A successfully refreshed from Google Patents.
US4064218A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Removal of phosgene from off-gases
Assignee: BASF SE
•
Filing: 1976-06-21
•
Granted: 1977-12-20
•
Expires: 1996-06-21
Abstract
Abstract Process for the removal of phosgene from an off-gas in which it is present in small quantities, by washing with an aqueous solution of alkali and ammonia.
Inventors
- 👤 Heinrich Scholz
- 👤 Martin Decker
- 👤 Franz Neumayr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 23:37
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/34; B01D53/46; B01D53/68; B01D53/70
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
55 words
A process for removing phosgene from off-gas which comprises washing the off-gas with an aqueous solution containing from 1 to 50% by weight of sodium hydroxide or potassium hydroxide and from about 0.1 to 10% by weight of ammonia, said washing step being carried out at a temperature of from about 10° to 100° C.
Claim 2
Dependent Claim
55 words
A process for removing phosgene from off-gas which comprises washing the off-gas with an aqueous solution containing from 1 to 50% by weight of sodium hydroxide or potassium hydroxide and from about 0.1 to 10% by weight of ammonia, said washing step being carried out at a temperature of from about 10° to 100° C.
Claim 3
Dependent Claim
24 words
A process as set forth in claim 1 wherein the amount of ammonia in the solution is from about 0.5 to 5% by weight.
Claim 4
Dependent Claim
22 words
A process as set forth in claim 2 wherein the temperature of the washing step is from about 40° to 60° C.
Claim 5
Dependent Claim
25 words
A process as set forth in claim 1, in which the treatment is carried out in a packed column or a column provided with baffles.
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) | 1980-12-19 | 1981-06-20 | 1981-12-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-12-19 | 1985-06-20 | 1985-12-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-12-19 | 1989-06-20 | 1989-12-20 | $7700.00 | Window Closed / Lapsed |