Synthesis of starch esters in ionic liquids

Abstract Chemical modification of corn starches with succinic anhydride or acetic anhydride was carried out using 1‐butyl‐3‐methylimidazolium chloride (BMIMCl) as a reaction medium. The reaction progress was followed in terms of the degree of substitution (DS) for the starch derivatives. The results showed that the homogeneous esterification of starch at 5 : 1 molar ratio of anhydride/anhydroglucose units at 100°C led to formation of acetates with DS ranging from 0.37 to 2.35 and succinates with DS ranging from 0.03 to 0.93. Moreover, the reaction media applied could be easily recycled and reused. Further, the formation of starch esters was confirmed by the presence of the carbonyl signal in the FTIR and NMR spectra. It was shown that the starch granules were mostly converted from their crystalline structure into amorphous state in the ionic liquid system under the given reaction conditions. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010