US4547570A
Expired / Lapsed
US
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Process for preparing cellulose ethers
Assignee: Dow Chemical Co
•
Filing: 1983-10-20
•
Granted: 1985-10-15
•
Expires: 2003-10-20
Abstract
Abstract Improved reaction efficiencies are obtained when water is removed during a reaction of alkali cellulose and an etherifying agent to produce cellulose ethers. The removal of water during the etherification reaction reduces the amount of by-products formed during the reaction.
Inventors
- 👤 Joseph L. Garner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 13:31
CPC Classifications
C; C08; C08B; C08B11/00; C08B11/02
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
41 words
In an etherification process for preparing cellulose ethers wherein alkali cellulose is reacted with an etherifying agent which also reacts with water, the improvement comprising removing water by distillation, during the reaction, whereby the efficiency of the etherification reaction is improved.
Claim 2
Dependent Claim
41 words
In an etherification process for preparing cellulose ethers wherein alkali cellulose is reacted with an etherifying agent which also reacts with water, the improvement comprising removing water by distillation, during the reaction, whereby the efficiency of the etherification reaction is improved.
Claim 3
Dependent Claim
19 words
The process of claim 1 wherein the etherification reaction is conducted in the presence of an inert organic diluent.
Claim 4
Dependent Claim
19 words
The process of claim 2 wherein the etherification reaction is conducted at a temperature of at least 100° C.
Claim 5
Dependent Claim
27 words
The process of claim 2 wherein the organic diluent and the water form an azeotropic mixture and water is distilled as an azeotrope with the organic diluent.
Claim 6
Dependent Claim
15 words
The process of claim 1 wherein the water is distilled continuously during the etherification reaction.
Claim 7
Dependent Claim
48 words
The process of claim 1 wherein the alkali cellulose contains water at the start of the etherification reaction and the weight ratio of water removed from the reaction to the water contained in the alkali cellulose at the start of the etherification reaction is at least about 0.6.
Claim 8
Dependent Claim
12 words
The process of claim 6 wherein said ratio is at least 1.0.
Claim 9
Dependent Claim
45 words
The process of claim 1 wherein alkali cellulose is prepared from about 0.8 to about 3.0 parts by weight of an alkali metal hydroxide per part by weight of cellulose and additional alkali metal hydroxide is added to the alkali cellulose during the etherification reaction.
Claim 10
Dependent Claim
12 words
The process of claim 1 wherein the etherifying agent comprises ethyl chloride.
Claim 11
Dependent Claim
12 words
The process of claim 4 wherein the etherifying agent is ethyl chloride.
Claim 12
Dependent Claim
12 words
The process of claim 8 wherein the etherifying agent is ethyl chloride.
Claim 13
Dependent Claim
19 words
The process of claim 8 wherein no water is removed following the addition of said additional alkali metal hydroxide.
Claim 14
Dependent Claim
67 words
In an etherification process for preparing cellulose ethers wherein alkali cellulose containing an amount of water is reacted with an etherifying agent which also reacts with water, the improvement comprising removing water by distillation during the reaction, whereby the weight ratio of water removed from the reaction to the water contained in the alkali cellulose at the start of the etherification reaction is at least about 0.3.
Claim 15
Dependent Claim
67 words
In an etherification process for preparing cellulose ethers wherein alkali cellulose containing an amount of water is reacted with an etherifying agent which also reacts with water, the improvement comprising removing water by distillation during the reaction, whereby the weight ratio of water removed from the reaction to the water contained in the alkali cellulose at the start of the etherification reaction is at least about 0.3.
Claim 16
Dependent Claim
14 words
The process of claim 13, wherein said weight ratio is at least about 0.6.
Claim 17
Dependent Claim
14 words
The process of claim 14, wherein said weight ratio is at least about 1.0.
References Cited (Backward Citations)
US1683682A
Cited
US1746663A
Cited
US1694127A
Cited
US2137343A
Cited
US2145273A
Cited
US2284860A
Cited
US2254249A
Cited
US2362900A
Cited
US2512338A
Cited
US3903076A
Cited
US4250305A
Cited
US4339574A
Cited
US4341892A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-10-14 | 1989-04-15 | 1989-10-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-10-14 | 1993-04-15 | 1993-10-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-10-14 | 1997-04-15 | 1997-10-15 | $7700.00 | Window Closed / Lapsed |