Claims
- 1. A process for preparing cellulose ethers from cellulose and alkylating agents, in the presence of a base and water and a water miscible cyclic ether as a suspending agent consisting essentially of dioxane and/or THF comprising the stages:
- a) alkalization,
- b) subsequent alkylation, and optionally stage
- c) hydroxyalkylation which would be performed between stages a) and b);
- wherein the water-miscible cyclic ether is admixed in
- 1) stage a) or,
- 2) if optional stage c) is performed then in stage a) or stage c) , and wherein after stage a) and before stage b) a part of the water-miscible cyclic ether together with a part of the .water are removed by distillation.
- 2. The process as claimed in claim 1, wherein a hydroxyalkylation c) takes place after stage a) and before stage b) and, optionally, the water-miscible, cyclic ether is admixed during stage c).
- 3. The process as claimed in claim 4, wherein up to 70% by weight of the suspending agent/water mixture admixed is removed.
- 4. The process as claimed in claim 1, wherein the alkalisation is carried out at between 0.degree. C. and 100.degree. C. and for between 5 minutes and 3 hours and the alkylation is carried out at a temperature between 20.degree. and 150.degree. C. over a time period of 15 minutes to 16 hours.
- 5. The process as claimed in claim 1, wherein after stage a), but before stage b), up to 70% by weight of the suspending agent/water mixture admixed is removed.
- 6. The process as claimed in claim 5, wherein 20-60% by weight of the suspending agent/water mixture admixed is removed.
- 7. The process as claimed in claim 1, wherein after stage c), up to 70% by weight of the suspending agent/water mixture admixed is removed.
- 8. The process as claimed in claim 7, wherein 20-60% by weight of the suspending agent/water mixture admixed is removed.
- 9. The process as claimed in claim 1, wherein the cellulose is cotton linters, chemical wood pulp or is present in a regenerated form as cellulose hydrate.
- 10. The process as claimed in claim 9, wherein the cellulose has a particle size less than 2.5 mm.
- 11. The process as claimed in claim 1, wherein the hydroxyalkylation is carried out at a temperature between 20.degree. and 150.degree. C. in a time period of 15 minutes to 16 hours.
- 12. The process as claimed in claim 4, wherein the hydroxyalkylation is carrier out at a temperature of 60.degree. to 120.degree. C. in a time period of 30 minutes to 6 hours.
- 13. The process as claimed in claim 12, wherein the alkylation is carried out at a temperature range between 60.degree. and 120.degree. C. over a time period of 30 minutes to 6 hours.
- 14. The process as claimed in claim 13, wherein the quantity of alkylating agent added is in the range of 0.1 to 10 mols per cellulose; the bases are present in an amount of 0.6 to 8.0 mols per mol of cellulose; the water is in the range of 3 to 20 mols per mol of cellulose; and hydroxyalkylation agent is alkylene oxide and said alkylene oxide is present in an amount from 0.5 to 5 mol per mol of cellulose.
- 15. The process as claimed in claim 1, wherein 2 to 30 parts by weight of water-miscible cyclic ethers are admixed per one part by weight of cellulose.
- 16. The process as claimed in claim 15, wherein 2 to 18 parts by weight of water-miscible cyclic ethers are admixed per one part by weight of cellulose.
- 17. The process as claimed in claim 15, wherein 2 to 9 parts by weight of water-miscible cyclic ethers are admixed per one part by weight of cellulose.
- 18. The process as claimed in claim 17, wherein 20 to 60% by weight of the suspending agent/water mixture admixed is removed.
Priority Claims (1)
Number |
Date |
Country |
Kind |
42 13 329.7 |
Apr 1992 |
DEX |
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Parent Case Info
This application is a continuation of application Ser. No. 08/050,583, filed Apr. 21, 1993, now abandoned.
US Referenced Citations (16)
Foreign Referenced Citations (2)
Number |
Date |
Country |
2929011 |
Feb 1981 |
DEX |
1468017 |
Oct 1981 |
DEX |
Non-Patent Literature Citations (1)
Entry |
Derwent Abstract of JP 01165601, Toho Chemical Ind. Ltd., Jun. 29, 1989. |
Continuation in Parts (1)
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Number |
Date |
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Parent |
50583 |
Apr 1993 |
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