Preparing esters from high-amylose starch using ionic liquids as catalysts

The use of different ionic liquids (IL), mainly 1- N-alkyl-3-methylimidazolium chlorides as possible catalysts for esterification of starch is reported. A high amylose maize starch is used and the esterification is performed with the aid of different carboxylic anhydrides. These are used both as a r...

Full description

Saved in:
Bibliographic Details
Published in:Carbohydrate polymers 2011-02, Vol.83 (4), p.1529-1533
Main Authors: Lehmann, André, Volkert, Bert
Format: Article
Language:English
Subjects:
acetates
activation energy
amylose
anhydrides
Applied sciences
catalysts
Catalyze
chlorides
corn starch
esterification
Exact sciences and technology
glucose
Ionic liquids
ions
molecular weight
Natural polymers
Physicochemistry of polymers
propionic acid
SEC-MALLS
solubility
Starch and polysaccharides
Starch ester
titration
Citations: Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The use of different ionic liquids (IL), mainly 1- N-alkyl-3-methylimidazolium chlorides as possible catalysts for esterification of starch is reported. A high amylose maize starch is used and the esterification is performed with the aid of different carboxylic anhydrides. These are used both as a reactant and a solvent for all reactions using a maximum of 1.2 molar equivalents (moleq) of IL per anhydro glucose unit (AGU). Highly substituted starch esters can be achieved within a 4–24 h reaction time depending on the molar ratios of ionic liquid and esterifying agent. The ionic liquids used for these reactions can easily be recovered and reused. The influence of the structure and amount of ionic liquid used in the preparation of starch acetate and starch propionate as model substances are analyzed in terms of their degree of substitution (titration), reaction rate, solubility and average molecular weight (SEC-MALLS). A study of the effects of different bases on degradation of the starch was investigated, too. We conclude that imidazolium-based ionic liquids with halogenides as counter ions can be used as catalysts for the esterification of starch and thus fulfill the definition of a recyclable catalyst that lowers activation energy.
ISSN:0144-8617
1879-1344
DOI:10.1016/j.carbpol.2010.10.002