US2675377A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of preparing sulfuric acid esters of cellulose
Assignee: Eastman Kodak Co
•
Filing: 1951-01-18
•
Granted: 1954-04-13
•
Expires: 1971-01-18
Abstract
No abstract record available.
Inventors
- 👤 Carl J Malm
- 👤 Carlton L Crane
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 15:59
CPC Classifications
C; C08; C08B; C08B5/00; C08B5/14
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
147 words
A METHOD FOR PREPARING SULFURIC ACID ESTERS OF CELLULOSE WHICH COMPRISES ESTERIFYING CELLULOSE WITH A BATH ESSENTIALLY CONSISTING OF ALCOHOL, SULFURIC ACID AND AS THE DILUENT THEREOF LIQUID SULFUR DIOXIDE, THE ALCOHOL IN THE BATH BEING SELECTED FROM THE ALIPHATIC ALCOHOLS OF 1-5 CARBON ATOMS THE PROPORTION OF SULFURIC ACID TO ALCOHOL IN THE BATH BEING 90-55% OF THE FORMER TO 10-45% OF THE LATTER, THE RATIO OF ALCOHOL-SULFURIC ACID TO CELLULOSE THEREIN BEING 6-12:1, AND THE RATIO OF LIQUID SULFUR DIOXIDE TO CELLULOSE THEREIN BEING 15-75:1, THE SULFURIC ACID USED BEING IN A SUFFICIENT AMOUNT TO PROMOTE THE REACTION BUT LESS THAN WILL CAUSE APPRECIABLE DISSOLVING OF SULFURIC ACID ESTERS OF CELLULOSE IN THE REACTION MASS, THE REACTION BEING CARRIED OUT AT A TEMPERATURE OF 0-40* F. FOR A SUFFICIENT TIME TO GIVE AS THE PRODUCT A CELLULOSE SULFATE WHICH IS SOLUBLE IN DILUTE AQUEOUS ALKALI.
Claim 2
Independent Claim
147 words
A METHOD FOR PREPARING SULFURIC ACID ESTERS OF CELLULOSE WHICH COMPRISES ESTERIFYING CELLULOSE WITH A BATH ESSENTIALLY CONSISTING OF ALCOHOL, SULFURIC ACID AND AS THE DILUENT THEREOF LIQUID SULFUR DIOXIDE, THE ALCOHOL IN THE BATH BEING SELECTED FROM THE ALIPHATIC ALCOHOLS OF 1-5 CARBON ATOMS THE PROPORTION OF SULFURIC ACID TO ALCOHOL IN THE BATH BEING 90-55% OF THE FORMER TO 10-45% OF THE LATTER, THE RATIO OF ALCOHOL-SULFURIC ACID TO CELLULOSE THEREIN BEING 6-12:1, AND THE RATIO OF LIQUID SULFUR DIOXIDE TO CELLULOSE THEREIN BEING 15-75:1, THE SULFURIC ACID USED BEING IN A SUFFICIENT AMOUNT TO PROMOTE THE REACTION BUT LESS THAN WILL CAUSE APPRECIABLE DISSOLVING OF SULFURIC ACID ESTERS OF CELLULOSE IN THE REACTION MASS, THE REACTION BEING CARRIED OUT AT A TEMPERATURE OF 0-40* F. FOR A SUFFICIENT TIME TO GIVE AS THE PRODUCT A CELLULOSE SULFATE WHICH IS SOLUBLE IN DILUTE AQUEOUS ALKALI.
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) | 1957-04-12 | 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 |