Location: Plant Polymer Research
Title: Reactions of Starch in Ionic Liquids Authors
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: September 10, 2009
Publication Date: September 12, 2009
Citation: Biswas, A., Shogren, R.L., Willett, J.L. 2009. Reactions of Starch in Ionic Liquids. Meeting Abstract. #. Technical Abstract: We found that starches are found to be soluble at 80 ºC in ionic liquids such as 1-butyl-3-methylimidazolium chloride (BMIMCl) and 1-butyl-3-methylimidazolium dicyanamide (BMIMdca) in concentration up to 10% (w/w). Higher concentrations of biopolymers in these novel solvents resulted in solutions with too high viscosity to stir. Solutions of both starch and zein in BMIMCl were acylated with anhydrides in presence of pyridine to give acetyl starch and benzoyl zein with various degrees of substitutions. Without pyridine the acylation reaction did not proceed. 1H NMR and IR spectroscopies were used to determine the degree of substitution of starch. Viscosity studies indicated that the starch underwent slight reduction in molecular weight during the course of acylation. Starch was also soluble in other non-conventional solvents such as choline chloride/oxalic acid and choline chloride/ZnCl2. We also carried out catalyst free esterification of maltodextrins in ionic liquid. Stearate esters of maltodextrin were obtained in various degree of substitution (DS) when vinyl stearate or stearic acid was heated with maltodextrin in ionic liquid 1-butyl-3-methylimidazolium cyanamide (bmim [dca]). Reaction temperatures of 75 ºC gave the highest values of DS (0.64) and reaction efficiency (64%). Structure and DS of the esters were confirmed by NMR, titration, GC, and elemental analysis. It was found that for some of the maltodextrin stearates the mixed solvent of chloroform/DMSO (70/30) was better than DMSO.