US3903075A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the preparation of water-insoluble hydroxybutyl cellulose
Assignee: Hoechst AG
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Filing: 1971-06-07
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Granted: 1975-09-02
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Expires: 1991-06-07
Abstract
Abstract This invention relates to a process for the preparation of hydroxybutyl cellulose which comprises etherifying alkali cellulose with butylene oxide in a quantity corresponding to at least four times the weight of cellulose present in the form of alkali cellulose, at a temperature of at least 60*C., continuing the reaction until at least 0.7 mole of butylene oxide per glucose unit has been used for substitution on the cellulose and washing the reaction product with water.
Inventors
- 👤 Wolfgang Schminke
- 👤 Hans Macholdt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 14:38
CPC Classifications
C; C08; C08B; C08B11/00; C08B11/02; C08B11/04; C08B11/08
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
77 words
A PROCESS FOR THE PREPARATION OF HYDROXY BUTLY CELLULOSE WHICH COMPRISES ETHERIFYING ALKALI CELLULOSE IN A SINGLE STAGE WITH BUTYLENE OXIDE IN A QUANTITY CORRESPONDING TO AT LEAST FOUR TIMES THE WEIGHT OF CELLULOSE PRESENT IN THE FORM OF ALKALI CELLULOSE, AT A TEMPERATURE OF AT LEAST 60*C, CONTINUING THE REACTION UNTIL 1.8 TO 3.0 MOLES OF BUTYLENE OXIDE PER GLUCOSE UNIT HAVE BEEN USED FOR SUBSTITUTION ON THE CELLULOSE, AND WASHING THE REACTION PRODUCT WITH WATER.
Claim 2
Dependent Claim
77 words
A PROCESS FOR THE PREPARATION OF HYDROXY BUTLY CELLULOSE WHICH COMPRISES ETHERIFYING ALKALI CELLULOSE IN A SINGLE STAGE WITH BUTYLENE OXIDE IN A QUANTITY CORRESPONDING TO AT LEAST FOUR TIMES THE WEIGHT OF CELLULOSE PRESENT IN THE FORM OF ALKALI CELLULOSE, AT A TEMPERATURE OF AT LEAST 60*C, CONTINUING THE REACTION UNTIL 1.8 TO 3.0 MOLES OF BUTYLENE OXIDE PER GLUCOSE UNIT HAVE BEEN USED FOR SUBSTITUTION ON THE CELLULOSE, AND WASHING THE REACTION PRODUCT WITH WATER.
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) | 1978-09-01 | 1979-03-03 | 1979-09-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-01 | 1983-03-03 | 1983-09-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-01 | 1987-03-03 | 1987-09-02 | $7700.00 | Window Closed / Lapsed |