Patent US2923706A successfully refreshed from Google Patents.
US2923706A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Manufacture of cellulose esters of aliphatic acids
Assignee: Canadian Celanese Ltd
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Filing: 1955-06-22
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Granted: 1960-02-02
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Expires: 1975-06-22
Abstract
No abstract record available.
Inventors
- 👤 Norman B Campbell
- 👤 Berthiaume Laurent
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 15:04
CPC Classifications
C; C08; C08B; C08B3/00; C08B3/06
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
144 words
PROCESS FOR THE MANUFACTURE OF LOWER ALIPHATIC ACID ESTERS OF CELLULOSE, WHICH COMPRISES ESTERIFYING CELLULOSE WITH AN ALIPHATIC ACID ANHYDRIDE CONTAINING FROM 2 TO 4 CARBON ATOMS IN THE MOLECULE IN THE PRESENCE OF AT LEAST SUFFICIENT ALIPHATIC AND CONTAINING 2-4 CARBON ATOMS IN THE MOLECULE TO DISSOLVE THE CELLULOSE ESTER AS IT IS FORMED, AND OF SULPHURIC ACID IN AMOUNT AT MOST 1% AS CATALYST, THE WHOLE OF THE SAID SULPHURIC ACID HAVING BEEN UNIFORMLY DISPERSED THROUGHOUT THE CELLULOSE IN THE COURSE OF AN ACTIVATING PRETREATMENT IN WHICH AN ALIPHATIC ACID CONTAING 1-4 CARBON ATOMS IN THE MOLECULE IS EMPLOYED, THE ESTERIFICATION BEING EFFECTED AT TEMPERATURE WHICH REACHE AT LEAST 50*C. AND RECOVERING THE CELLULOSE ESTER UPON COMPLETION OF ESTERIFICATION AND NEUTRALIZATION OF THE CATALYST, WITHOUT REQUIRING ANY HYDROLYSIS OR OTHER ACTION TO REMOVE THE SULPHURIC ACID FROM CHEMICAL COMBINATION WITH THE ESTER.
Claim 2
Dependent Claim
144 words
PROCESS FOR THE MANUFACTURE OF LOWER ALIPHATIC ACID ESTERS OF CELLULOSE, WHICH COMPRISES ESTERIFYING CELLULOSE WITH AN ALIPHATIC ACID ANHYDRIDE CONTAINING FROM 2 TO 4 CARBON ATOMS IN THE MOLECULE IN THE PRESENCE OF AT LEAST SUFFICIENT ALIPHATIC AND CONTAINING 2-4 CARBON ATOMS IN THE MOLECULE TO DISSOLVE THE CELLULOSE ESTER AS IT IS FORMED, AND OF SULPHURIC ACID IN AMOUNT AT MOST 1% AS CATALYST, THE WHOLE OF THE SAID SULPHURIC ACID HAVING BEEN UNIFORMLY DISPERSED THROUGHOUT THE CELLULOSE IN THE COURSE OF AN ACTIVATING PRETREATMENT IN WHICH AN ALIPHATIC ACID CONTAING 1-4 CARBON ATOMS IN THE MOLECULE IS EMPLOYED, THE ESTERIFICATION BEING EFFECTED AT TEMPERATURE WHICH REACHE AT LEAST 50*C. AND RECOVERING THE CELLULOSE ESTER UPON COMPLETION OF ESTERIFICATION AND NEUTRALIZATION OF THE CATALYST, WITHOUT REQUIRING ANY HYDROLYSIS OR OTHER ACTION TO REMOVE THE SULPHURIC ACID FROM CHEMICAL COMBINATION WITH THE ESTER.
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) | 1963-02-01 | 1963-08-03 | 1964-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1967-02-01 | 1967-08-03 | 1968-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1971-02-01 | 1971-08-03 | 1972-02-02 | $7700.00 | Window Closed / Lapsed |