Patent US2849443A successfully refreshed from Google Patents.
US2849443A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Production of organic acid esters of cellulose
Assignee: Celanese Corp
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Filing: 1955-03-03
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Granted: 1958-08-26
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Expires: 1975-03-03
Abstract
No abstract record available.
Inventors
- 👤 Henry W Steinmann
- 👤 Dunay Michael
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 07:32
CPC Classifications
C; C08; C08B; C08B3/00
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
92 words
IN A PROCESS FOR THE PRODUCTION OF ORGANIC ACID ESTERS OF CELLULOSE, THE STEPS WHICH COMPRISE ESTERIFYING CELLULOSE WITH AN ORGANIC ACID ANHYDRIDE IN THE PRESENCE OF A WATERIMMISCIBLE SOLVENT FOR THE ESTER BEING FORMED WHEREBY THERE WILL BE OBTAINED AT THE COMPLETION OF THE ESTERIFICATION A SUBSTANTIALLY HOMOGENEOUS SOLUTION, PASSING THE SAID SOLUTION OVER ONE SURFACE OF A MEMEBRANE, AND PASSING AN EXTRACTING LIQUID OVER THE OTHER, SURFACE OF THE MEMBRANE WHEREBY IMPURITIES IN THE SOLUTION WILL PASS THROUGH THE MEMBRANE BY DIALYSSI AND BE CARRIED AWAY BY THE EXTRACTING LIQUID.
Claim 2
Dependent Claim
92 words
IN A PROCESS FOR THE PRODUCTION OF ORGANIC ACID ESTERS OF CELLULOSE, THE STEPS WHICH COMPRISE ESTERIFYING CELLULOSE WITH AN ORGANIC ACID ANHYDRIDE IN THE PRESENCE OF A WATERIMMISCIBLE SOLVENT FOR THE ESTER BEING FORMED WHEREBY THERE WILL BE OBTAINED AT THE COMPLETION OF THE ESTERIFICATION A SUBSTANTIALLY HOMOGENEOUS SOLUTION, PASSING THE SAID SOLUTION OVER ONE SURFACE OF A MEMEBRANE, AND PASSING AN EXTRACTING LIQUID OVER THE OTHER, SURFACE OF THE MEMBRANE WHEREBY IMPURITIES IN THE SOLUTION WILL PASS THROUGH THE MEMBRANE BY DIALYSSI AND BE CARRIED AWAY BY THE EXTRACTING LIQUID.
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) | 1961-08-25 | 1962-02-24 | 1962-08-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-08-25 | 1966-02-24 | 1966-08-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-08-25 | 1970-02-24 | 1970-08-26 | $7700.00 | Window Closed / Lapsed |