Inulin esterification

More recently, the chemo-enzymatic synthesis of inulin-containing hydrogels was reported [54]. The key point was the solubility of inulin [a mixture of oligomers and polymers containing 2-60 (or more) 5-2,1 linked D-fructose molecules having a glucose unit as the initial residue] in dimethylformamide (DMF), a fact that allowed its esterification by action of a protease from Bacillus subtilis. 

Esterification of succinic anhydride in dimethylformamide with 4-dimethylaminopyridine gives O-succinoylated inulin (Vermeersch and Schacht, 1985), which can be used as a drug carrier. Esterification of alkenyl succinic anhydrides having chain lengths of C8 to C20 in dimethylformamide, with or without a catalyst, produces potential deflocculating agents for use in detergents... 

Another interesting HMF-derived compound is levulinic acid formed together with formic acid by solid acid catalysis. A one-pot cascade route from c.g. inulin seems feasible. Manzer et al. [37] give examples in which an esterification step with an alkene is coupled as well. The... 

As an answer to the growing demand for products made from renewable resources and with (modified) starch as a reference in mind, a lot of these starches have been devoted to the chemical modification of inulin [3]. Hydrophobization of inulin, e.g. grafting of alkyl chains on to the inulin backbone and as such obtaining an inulin derivative showing the wanted amphiphilic character, can be done in several ways by esterification, by etherification or by carbamoylation. The reactions are usually performed in solvents like pyridine, dimethylformamide or dimethylsulfoxide, using catalysts like, for example, sodium acetate, potassium carbonate or triethylamine. 

Esterification can be carried out using conventional reactions with acid chloride or with acid anhydrides. The etherification of inulin can be done using alkylepoxides as reactant. Carbamoylation reactions using alkyl isocyanate can be performed, obtaining inulin carbamates. 

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