US2690994A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Formaldehyde purification by use of alcohols
Assignee: Individual
•
Filing: 1950-02-01
•
Granted: 1954-10-05
•
Expires: 1970-02-01
Abstract
No abstract record available.
Inventors
- 👤 James F Mccants
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 08:03
CPC Classifications
C; C07; C07C; C07C45/00; C07C45/78; C07C45/81; C07C45/82; C07C45/783; C07C45/84
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
60 words
A METHOD FOR CONCENTRATING AQUEOUS SOLUTIONS OF FORMALDEHYDE COMPRISING PASSING VAPORS OF THE FORMALDEHYDE AND WATER UPWARDLY THROUGH A FRACTIONATING COLUMN, PROVIDING A REFLUX IN SAID COLUMN OF A WATER-SOLUBLE ALCOHOL SELECTED FROM THE GROUP CONSISTING OF ETHANOL, ISOPROPANOL, NORMAL PROPANOL AND TERTIARY BUTANOL, WHILE MAINTAINING THE TEMPERATURE IN SAID COLUMN AT A TEMPERATURE ABOVE ABOUT 80* C., AND WITHDRAWING
Claim 2
Independent Claim
60 words
A METHOD FOR CONCENTRATING AQUEOUS SOLUTIONS OF FORMALDEHYDE COMPRISING PASSING VAPORS OF THE FORMALDEHYDE AND WATER UPWARDLY THROUGH A FRACTIONATING COLUMN, PROVIDING A REFLUX IN SAID COLUMN OF A WATER-SOLUBLE ALCOHOL SELECTED FROM THE GROUP CONSISTING OF ETHANOL, ISOPROPANOL, NORMAL PROPANOL AND TERTIARY BUTANOL, WHILE MAINTAINING THE TEMPERATURE IN SAID COLUMN AT A TEMPERATURE ABOVE ABOUT 80* C., AND WITHDRAWING
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) | 1957-10-04 | 1958-04-05 | 1958-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1961-10-04 | 1962-04-05 | 1962-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1965-10-04 | 1966-04-05 | 1966-10-05 | $7700.00 | Window Closed / Lapsed |