Method for producing polysaccharide esters or polysaccharide mixed esters

摘要

The invention relates to a method for producing polysaccharide esters or polysaccharide mixed esters, in which a polysaccharide or a modified polysaccharide is converted with at least one esterification reagent and at least one halogenide component, an imidazole compound which is generated in situ being used as catalyst.

主权项

1. A method of
esterifying at least one selected from the group consisting of a starch starting material and a modified starch starting material to provide at least one selected from the group consisting of a starch ester and a starch mixed ester, the method comprising:
combining the starch starting material or modified starch starting material with at least one esterification reagent selected from the group consisting of a carboxylic acid, carboxylic acid anhydride, a carboxylic acid ester, and mixtures thereof, to form a reaction mixture;heating the reaction mixture to 90° C. to less than 120° C.;adding N-methyl imidazole to the reaction mixture;increasing the temperature of the reaction mixture to greater than 90° C. to less than or equal to 120° C.;adding at least one halogenide component selected from the group consisting of a carboxylic acid halogenide, halogenide ether, alkylhalogenide, a halogenated carboxylic acid, and mixtures thereof, and optionally at least one additional esterification reagent selected from the group consisting of a carboxylic acid, carboxylic acid anhydride, a carboxylic acid ester, and mixtures thereof; andallowing the reaction mixture to react to form the starch ester, mixed starch ester, or combination thereof, wherein the esterifying is complete within about 24 hours;wherein the reaction generates an imidazole compound of the general formula (I) wherein X− is a counterion, wherein the imidazole compound of formula (I) is a catalyst in the esterification reaction, wherein a molar ratio of the N-methyl imidazole to the starch starting material or the modified starch starting material is in the range of 1:2 to 1:0.3, and wherein the molar ratio of the N-methyl imidazole to the halogenide component is in the range of 1:1 to 1:0.4.