Process for the preparation of cellulose ethers from ammonia-activated cellulose
First Claim
1. A process for the preparation of water-soluble cellulose ethers, comprising the steps of:
- (a) activating cellulose with ammonia;
(b) alkalizing the activated cellulose with an alkalizing agent in the presence of ammonia, said alkalizing agent comprising an aqueous solution of an alkali metal hydroxide;
(c) removing the ammonia from the alkali cellulose in the presence of the alkalizing agent; and
(d) etherifying the alkali cellulose with an etherifying agent in the presence of an organic solvent.
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Abstract
A process is disclosed for the preparation of water-soluble cellulose ethers, comprising the steps of activating cellulose with ammonia, alkalizing the activated cellulose, and etherifying the alkali cellulose. In the process, the activated cellulose is alkalized in the presence of ammonia and, optionally, in the presence of an organic solvent, and the ammonia is removed from the alkali cellulose in the presence of the alkalizing agent and, optionally, the organic solvent. Etherification proceeds in a medium which contains at least portions of said organic solvent. The organic solvent comprises, in particular, an alkanol which has from 1 to 6 carbon atoms. For the etherification step, carboxymethylation or hydroxyethylation is preferred.
21 Citations
15 Claims
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1. A process for the preparation of water-soluble cellulose ethers, comprising the steps of:
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(a) activating cellulose with ammonia; (b) alkalizing the activated cellulose with an alkalizing agent in the presence of ammonia, said alkalizing agent comprising an aqueous solution of an alkali metal hydroxide; (c) removing the ammonia from the alkali cellulose in the presence of the alkalizing agent; and (d) etherifying the alkali cellulose with an etherifying agent in the presence of an organic solvent. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification