Patent US3969901A successfully refreshed from Google Patents.
Patent JPH04106941A successfully refreshed from Google Patents.
Patent US372124A successfully refreshed from Google Patents.
Patent US288677A successfully refreshed from Google Patents.
US2829160A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Purification of terephthalic acid
Assignee: Solutia Inc
•
Filing: 1953-10-12
•
Granted: 1958-04-01
•
Expires: 1973-10-12
Abstract
No abstract record available.
Inventors
- 👤 Carlyle J Stehman
- 👤 Clarence E Hieserman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 15:46
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/42; C07C51/02; C07C51/487
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
71 words
A PROCESS FOR PURIFYING TEREPHTHALIC ACID COMPRISING, DISSOLVING CRUDE TEREPHTHALIC ACID IN PYRIDINE, REACTING THE CRUDE TEREPHTHALIC ACID, WHILE DISSOLVED IN THE PYRIDINE, WITH A COMPOUND SELECTED FROM THE GROUP CONSISTING OF ISOPROPYLAMINE AND MORPHOLINE TO FORM AN AMINE SALT OF TEREPHTHALIC ACID, RECRYSTALLIZING THE AMINE SALT FROM ETHYLENE GLYCOL, DISSOLVING THE AMINE SALT IN WATER, ACIDIFYING THE AQUEOUS SOLUTION OF THE AMINE SALT, AND RECOVERING THE PURIFIED, INSOLUBLE TEREPHTHALIC ACID.
Claim 2
Dependent Claim
71 words
A PROCESS FOR PURIFYING TEREPHTHALIC ACID COMPRISING, DISSOLVING CRUDE TEREPHTHALIC ACID IN PYRIDINE, REACTING THE CRUDE TEREPHTHALIC ACID, WHILE DISSOLVED IN THE PYRIDINE, WITH A COMPOUND SELECTED FROM THE GROUP CONSISTING OF ISOPROPYLAMINE AND MORPHOLINE TO FORM AN AMINE SALT OF TEREPHTHALIC ACID, RECRYSTALLIZING THE AMINE SALT FROM ETHYLENE GLYCOL, DISSOLVING THE AMINE SALT IN WATER, ACIDIFYING THE AQUEOUS SOLUTION OF THE AMINE SALT, AND RECOVERING THE PURIFIED, INSOLUBLE TEREPHTHALIC ACID.
References Cited (Backward Citations)
US2742496A
Cited
US2664440A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1961-03-31 | 1961-09-30 | 1962-04-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-03-31 | 1965-09-30 | 1966-04-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-03-31 | 1969-09-30 | 1970-04-01 | $7700.00 | Window Closed / Lapsed |