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US4024335A
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Homogeneous hydroxy-alkylation of cellulose
Assignee: Union Carbide Corp
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Filing: 1976-05-04
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Granted: 1977-05-17
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Expires: 1996-05-04
Abstract
Abstract A solvent mixture consisting of dimethyl sulfoxide and formaldehyde is used for the hydroxy-alkylation of cellulose.
Inventors
- 👤 Myron Donald Nicholson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 11:54
CPC Classifications
C; C08; C08B; C08B11/00; C08B11/02; C08B11/04; C08B11/08
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
59 words
The method of hydroxy-alkylating cellulose which comprises contacting a slurry of cellulose and dimethyl sulfoxide containing up to about 15 percent cellulose with sufficient formaldehyde to effect a homogeneous solution and then contacting said solution with a 1,2-alkylene oxide in the presence of a catalyst at a temperature of about 0° to 110° C. for at least one hour.
Claim 2
Independent Claim
59 words
The method of hydroxy-alkylating cellulose which comprises contacting a slurry of cellulose and dimethyl sulfoxide containing up to about 15 percent cellulose with sufficient formaldehyde to effect a homogeneous solution and then contacting said solution with a 1,2-alkylene oxide in the presence of a catalyst at a temperature of about 0° to 110° C. for at least one hour.
Claim 3
Dependent Claim
17 words
Method claimed in claim 1 wherein the concentration of cellulose in the homogeneous solution is about 15%.
Claim 4
Dependent Claim
12 words
Method claimed in claim 1 wherein the 1,2-alkylene oxide is ethylene oxide.
Claim 5
Dependent Claim
12 words
Method claimed in claim 1 wherein the 1,2-alkylene oxide is 1,2-propylene oxide.
Claim 6
Dependent Claim
12 words
Method claimed in claim 1 wherein the 1,2-alkylene oxide is 1,2-butylene oxide.
Claim 7
Dependent Claim
26 words
Method claimed in claim 1 wherein the 1,2-alkylene oxide is contacted with the homogeneous solution at a temperature of about 20° C. to about 60° C.
References Cited (Backward Citations)
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US1863208A
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US2679449A
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US3023183A
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US3278521A
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US3236669A
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US3644082A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-05-16 | 1980-11-15 | 1981-05-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-16 | 1984-11-15 | 1985-05-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-16 | 1988-11-15 | 1989-05-17 | $7700.00 | Window Closed / Lapsed |