Process for the preparation of an ester from starch and a monocarboxylic acid, and a composition based on the starch ester thus prepared.

摘要

Preparation of a starch ester having an m̅n̅ of 1000-50 000 and a degree of substitution of 0,4-3,0, by heating a mixture of starch, a C1-7 monocarboxylic acid, water, and optionally a catalyst and meanwhile withdrawing water until the ester being formed has attained the desired degree of substitution. Optionally remaining free hydroxyl groups may be esterified by reaction with a carboxylic anhydride or - halide. The resulting solution may be treated to neutralize remaining free monocarboxylic acid by mixing it with an esterifiable hydroxyl compound and esterifying it at 40-270°C under the removal of water. In this way, use is made of cheap ingredients, and the resulting product is suitable for immediate use in a number of applications, e.g., as binder in coating compositions.