Method of making starch acetate using an acid catalyst
AssigneeHoechst Celanese Corporation
InventorBernice I. Feuer
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Abstract
Methods of synthesizing starch acetate containing at least 20% high molecular weight carbohydrates using a MSA catalyst alone, or in combination with a co-catalyst promoting cross-linking, such a phosphoric acid, are described. The MSA is desirably added slowly following beginning of the exothermic reaction of starch, acetic acid and acetic anhydride.
Claims24
A method for the production of starch ester polymer comprising
- catalyzing the synthesis of starch esters from the reaction of
- (a) a starch,
- (b) a carboxylic acid selected from carboxylic acids which are liquid at room temperature, and
- (c) a carboxylic anhydride, selected from carboxylic anhydrides which are liquid at room temperature with an acid catalyst which does not generate oxidation products and does not depolymerize the starch,
- wherein the starch ester is characterized by at least about 20% high molecular weight carbohydrates, as determined using size exclusion chromatography, and is white in color.
The method according to claim, 1 wherein said catalyst is an aryl sulfonic acid selected from the group consisting of toluenesulfonic acid, benzene sulfonic acid, and 2,4-dimethylbenzene sulfonic acid.
A method for the production of starch acetate polymer comprising the steps of:
- heating corn starch, with acetic acid and acetic anhydride in the presence of an acid catalyst which does not generate oxidation products and does not depolymerize the starch under conditions at which the reaction reaches exotherm;
- and
- precipitating starch acetate from said reaction product, wherein said starch acetate is characterized by at least about 20% high molecular weight carbohydrates, as determined using size exclusion chromatography, is white in color and is soluble in acetone and water.
Dependencies are inferred from the claim text.