Ether cellulose ethers

Action of acids on cellulose ethers. Cellulose ethers, like cellulose, are hydrolyzable by acids. Methods for viscosity reduction of the ethers have been proposed which involve treatment of the ether with sulfuric acid31 or with gaseous hydrogen chloride.32... 

Cellulose Ethers. Cellulose ethers are formed when cellulose, in the presence of alkali or as alkali cellulose, is treated with alkyl or arylalkyl halides. Two types of reaction are employed in the preparation of cellulose ethers. The most common is nucleophilic substitution. Methylation of alkali cellulose with a methyl halide is an example of this type. The other type of etherification reaction is Michael addition. This reaction proceeds by way of an alkali-catalyzed addition of an activated vinyl group to the cellulose. The reaction of acrylonitrile with alkali cellulose is a typical example. The general reaction is outlined in Scheme 4. 

Brandt, L. (2002) Cellulose ethers - cellulose ethers, Ullmann s Encyclopedia of Industrial Chemistry, WUey-VCH Verlag GmbH, Weinheim. 

P. are viscous liquids, which are either strongly alkaline, aqueous solutions that contain - methyl-cellulose or acrylic polymers as thickener or are solvent-based (e. g., methylene chloride) and neutral. The latter are thickened by ->methylcellulose of high DS, - hydroxyethylcellulose, - hydroyx-propylcellulose and their mixed ethers (- cellulose ethers). Some contain - ethylcellulose. 

Mixed alginate salts Mixed catalysts Mixed cellulose ethers... 

Two important classes are cellulose esters (qv) and cellulose ethers (qv). Cellulose esters are not water soluble and are not discussed here cellulose ethers are an important segment of water-soluble polymers. 

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