Patent US4278790A successfully refreshed from Google Patents.
US4278790A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Novel cellulose solutions
Assignee: Hopkins Agricultural Chemical Co
•
Filing: 1980-03-07
•
Granted: 1981-07-14
•
Expires: 2000-03-07
Abstract
Abstract Cellulose solutions containing cellulose dissolved in lithium chloride and dimethylacetamide are useful in preparing cellulose derivatives. The solutions may contain up to about 8% lithium chloride and up to about 3% cellulose. The preparation of cellulose derivatives using the cellulose solutions is also described.
Inventors
- 👤 Charles L. McCormick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:56
CPC Classifications
C; C08; C08J; C08J3/00; C08J3/02; C08J3/09; C08J3/091; C08J3/096; C08B; C08B1/00; C08B1/003; C08B11/00; C08K; C08K3/00; C08K3/16; C08J2301/00; C08J2301/02
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
10 words
A homogeneous solution containing cellulose in lithium chloride and dimethylacetamide.
Claim 2
Dependent Claim
10 words
A homogeneous solution containing cellulose in lithium chloride and dimethylacetamide.
Claim 3
Dependent Claim
17 words
A solution of claim 1 which contains up to about 8% lithium chloride on a weight/weight basis.
Claim 4
Dependent Claim
16 words
A solution of claim 1 containing up to about 3% of cellulose on a weight/weight basis.
Claim 5
Independent Claim
21 words
The method of preparing a homogeneous solution of cellulose which comprises adding cellulose to a solution of lithium chloride in dimethylacetamide.
Claim 6
Independent Claim
21 words
The method of preparing a homogeneous solution of cellulose which comprises adding cellulose to a solution of lithium chloride in dimethylacetamide.
Claim 7
Dependent Claim
26 words
The method of claim 4 in which the solution of lithium chloride in dimethylacetamide containing cellulose is alternately heated and cooled until the cellulose is dissolved.
Claim 8
Dependent Claim
20 words
The method of claim 4 in which the solution contains up to about 8% lithium chloride on a weight/weight basis.
Claim 9
Dependent Claim
25 words
In the method of preparing cellulose derivatives from cellulose, the step which comprises first dissolving the cellulose in a solution of lithium chloride and dimethylacetamide.
Claim 10
Dependent Claim
25 words
In the method of preparing cellulose derivatives from cellulose, the step which comprises first dissolving the cellulose in a solution of lithium chloride and dimethylacetamide.
Claim 11
Dependent Claim
35 words
In the method of preparing cellulose derivatives by chemical reactions utilizing the hydroxyl functionality of the cellulose, the improvement which comprises using as the cellulose reactant, a solution of cellulose in lithium chloride and dimethylacetamide.
Claim 12
Dependent Claim
35 words
In the method of preparing cellulose derivatives by chemical reactions utilizing the hydroxyl functionality of the cellulose, the improvement which comprises using as the cellulose reactant, a solution of cellulose in lithium chloride and dimethylacetamide.
Claim 13
Dependent Claim
16 words
The method of claim 8 in which the cellulose derivative being prepared is a cellulose ether.
Claim 14
Independent Claim
33 words
A method of separating lignin from cellulose which comprises dissolving the cellulose in a solution of lithium chloride and dimethylacetamide and then separating the lignin from the cellulose by differential precipitation using methanol.
Claim 15
Independent Claim
33 words
A method of separating lignin from cellulose which comprises dissolving the cellulose in a solution of lithium chloride and dimethylacetamide and then separating the lignin from the cellulose by differential precipitation using methanol.
References Cited (Backward Citations)
CA876148A
Cited
US1746663A
Cited
US1924238A
Cited
US3236669A
Cited
US3935022A
Cited
US4028132A
Cited
US4059457A
Cited
US4062921A
Cited
US4097666A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-07-13 | 1985-01-12 | 1985-07-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-07-13 | 1989-01-12 | 1989-07-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-07-13 | 1993-01-12 | 1993-07-14 | $7700.00 | Window Closed / Lapsed |