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US 4,129,722 AGranted
Process for the preparation of high D. S. polysaccharides
AssigneeNational Starch and Chemical Corporation
InventorsCarmine P. Iovine, Dilip K. Ray-Chaudhuri
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Abstract
Water soluble and water swellable highly substituted polysaccharide derivatives are prepared in highly concentrated aqueous solutions under controlled reaction conditions. The resultant derivatives are produced efficiently and readily isolated in solid form.
Claims11
A process for the production of a water-soluble or water swellable highly substituted polysaccharide derivative comprising the steps of
- (a) suspending a polysaccharide substrate in an organic solvent, which solvent is immiscible with the aqueous derivatizing reagent phase, does not dissolve the reagent or polysaccharide derivative as it is formed, has a boiling point at or above the temperature of the derivatization reaction, is insensitive to alkali and does not participate in the derivatization reaction;
- (b) adding thereto an aqueous solution of the derivatizing reagent;
- (c) derivatizing the resultant mixture in the presence of alkali if required, with agitation at a temperature of 10.degree. to 100.degree. C.;
- and
- (d) isolating the resultant derivative;
- wherein it is required that either the aqueous solution or the organic polysaccharide suspension, or both, contain a cationic, anionic or nonionic surfactant and that the solids concentration is greater than 50% by weight of the total aqueous system.
3 more elements
Dependencies are inferred from the claim text.