Date of this Version
United States Patent, Patent No.: US 9,637,560 B2
A reactive extrusion process for the production of substituted polysaccharides, in particular, cellulose acetate, starch acetate, carboxymethyl cellulose, and carboxymethyl starch.
The present application claims the benefit of PCT/ US20111059785 filed on Nov. 8, 2011, which claimed the benefit of U.S. provisional application 611411,521, filed on Nov. 9, 2010, U.S. provisional application 611411,992, filed on Nov. 10, 2010, and U.S. provisional application 611472, 748, filed on Apr. 7, 2011, each of which is which is incorporated herein by reference in its entirety.
The production of substituted polysaccharides such as starch and cellulose acetates and carboxymethylated starches and celluloses have typically been produced using batch reactors. During such production methods, the starch or cellulose is suspended in a mixture comprising the reactants and usually a catalyst. Undesirably, such processes require significant amounts of solvents and may require significantly more the stoichiometric amounts or reactants each of which results in waste and the higher associated costs (e.g., financial, environmental, and health) in both the production of the desired product and the treatment and disposal of waste.