US4009329A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Bioresistant cellulose ethers
Assignee: Union Carbide Corp
•
Filing: 1975-11-14
•
Granted: 1977-02-22
•
Expires: 1995-11-14
Abstract
Abstract Cellulose ethers which are resistant to enzyme catalyzed hydrolysis can be prepared by using a mixture of sodium and lithium hydroxides as the catalysts in conjunction with etherification reagents, such as, epoxides or alkyl halides.
Inventors
- 👤 William Charles Arney
- 👤 Clarence Alfred Williams
- 👤 Joseph Edward Glass, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 18:03
CPC Classifications
C; C08; C08B; C08B11/00; C08B11/02; C08B11/04; C08B11/08
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
82 words
In the method of preparing cellulose ethers by contacting the unsubstituted anhydroglucose units of cellulose with one or more etherification agents in the presence of a catalyst, the improvement which comprises using a mixture of sodium and lithium hydroxides as the catalyst with a weight ratio of total hydroxide:cellulose of about 0.1 to about 0.8 and a weight ratio of lithium hydroxide:sodium hydroxide of about 0.1 to about 10, whereby a cellulose ether which is resistant to enzyme catalyzed hydrolysis is obtained.
Claim 2
Dependent Claim
82 words
In the method of preparing cellulose ethers by contacting the unsubstituted anhydroglucose units of cellulose with one or more etherification agents in the presence of a catalyst, the improvement which comprises using a mixture of sodium and lithium hydroxides as the catalyst with a weight ratio of total hydroxide:cellulose of about 0.1 to about 0.8 and a weight ratio of lithium hydroxide:sodium hydroxide of about 0.1 to about 10, whereby a cellulose ether which is resistant to enzyme catalyzed hydrolysis is obtained.
Claim 3
Dependent Claim
18 words
Method claimed in claim 1 wherein the weight ratio of total hydroxide:cellulose is about 0.2 to about 0.5.
Claim 4
Dependent Claim
19 words
Method claimed in claim 1 wherein the weight ratio of lithium hydroxide:sodium hydroxide is about 0.5 to about 1.5.
Claim 5
Dependent Claim
29 words
Method claimed in claim 1 wherein the etherification of cellulose is carried out in an aqueous slurry with the weight ratio of water:cellulose being about 0.5 to about 10.
Claim 6
Dependent Claim
27 words
Method claimed in claim 4 wherein the aqueous slurry is diluted with an organic diluent in a weight ratio of diluent:cellulose of about 5 to about 20.
Claim 7
Dependent Claim
64 words
Method claimed in claim 1 wherein the etherification reagent is a cyclic organic compound having the formula: ##STR3## wherein R is a monovalent radical selected from the group consisting of hydrogen, alkyl having 1 to 10 carbon atoms and aryl or aralkyl having 6 to 12 carbon atoms, and Y is a divalent radical selected from the group consisting of --O--, --S--, or --NR--.
Claim 8
Dependent Claim
13 words
Method claimed in claim 6 wherein the cyclic organic compound is ethylene oxide.
Claim 9
Dependent Claim
13 words
Method claimed in claim 6 wherein the cyclic organic compound is propylene oxide.
Claim 10
Dependent Claim
47 words
Method claimed in claim 1 wherein the etherification reagent is a halide having the formula: R' -- X wherein R' is a monovalent radical selected from the class consisting of alkyl having 1 to 10 carbon atoms and aryl or aralkyl having 6 to 12 carbon atoms.
Claim 11
Dependent Claim
12 words
Method claimed in claim 9 wherein the halide is an alkyl halide.
Claim 12
Dependent Claim
12 words
Method claimed in claim 10 wherein the alkyl halide is methyl chloride.
References Cited (Backward Citations)
US2254249A
Cited
US2831852A
Cited
US2824779A
Cited
US2985501A
Cited
US3032549A
Cited
US3567360A
Cited
US3761465A
Cited
US3709876A
Cited
US3769247A
Cited
US3873518A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-02-22 | 1980-08-23 | 1981-02-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-02-22 | 1984-08-23 | 1985-02-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-02-22 | 1988-08-23 | 1989-02-22 | $7700.00 | Window Closed / Lapsed |