US2675346A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Concentration of formaldehyde by distillation and fractional condensation
Assignee: Celanese Corp
•
Filing: 1949-11-04
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Granted: 1954-04-13
•
Expires: 1969-11-04
Abstract
No abstract record available.
Inventors
- 👤 Alexander F Maclean
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 06:17
CPC Classifications
C; C08; C08G; C08G2/00; C08G2/08; C07; C07C; C07C45/00; C07C45/78; C07C45/81; C07C45/82
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
104 words
PROCESS FOR THE PRODUCTION OF PARAFORMALDEHYDE, WHICH COMPRISES SUBJECTING A DILUTE AQUEOUS SOLUTION OF FORMALDEHYDE TO DISTILLATION UNDER A PRESSURE OF ABOUT 30 TO 45 POUNDS PER SQUARE INCH GAGE, REDUCING THE PRESSURE ON THE VAPOR DISTILLATE TO A PRESSURE OF ABOUT 5 TO 15 POUNDS PER SQUARE INCH ABSOLUTE, PASSING THE VAPORS THROUGH A PLURALITY OF COOLING ZONES IN EACH OF WHICH A PARTIAL CONDENSATION OF THE VAPOR TAKES PLACE, REMOVING THE CONDENSED LIQUID FROM EACH ZONE RAPIDLY SO THAT THE RESIDENCE TIME OF THE CONDENSED LIQUID IN THE COOLING ZONE IS LESS THAN ABOUT ONE SECOND, THE TOTAL AMOUNT OF LIQUID SO
Claim 2
Dependent Claim
104 words
PROCESS FOR THE PRODUCTION OF PARAFORMALDEHYDE, WHICH COMPRISES SUBJECTING A DILUTE AQUEOUS SOLUTION OF FORMALDEHYDE TO DISTILLATION UNDER A PRESSURE OF ABOUT 30 TO 45 POUNDS PER SQUARE INCH GAGE, REDUCING THE PRESSURE ON THE VAPOR DISTILLATE TO A PRESSURE OF ABOUT 5 TO 15 POUNDS PER SQUARE INCH ABSOLUTE, PASSING THE VAPORS THROUGH A PLURALITY OF COOLING ZONES IN EACH OF WHICH A PARTIAL CONDENSATION OF THE VAPOR TAKES PLACE, REMOVING THE CONDENSED LIQUID FROM EACH ZONE RAPIDLY SO THAT THE RESIDENCE TIME OF THE CONDENSED LIQUID IN THE COOLING ZONE IS LESS THAN ABOUT ONE SECOND, THE TOTAL AMOUNT OF LIQUID SO
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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) | 1957-04-12 | 1957-10-12 | 1958-04-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-04-12 | 1961-10-12 | 1962-04-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-04-12 | 1965-10-12 | 1966-04-13 | $7700.00 | Window Closed / Lapsed |