Esterification Mechanism of Bagasse Modified with Glutaric Anhydride in 1-Allyl-3-methylimidazolium Chloride

Abstract

The esterification of bagasse with glutaric anhydride could increase surface adhesion compatibility and the surface of derived polymers has the potential of immobilizing peptides or proteins for biomedical application. Due to its complicated components, the esterification mechanism of bagasse esterified with glutaric anhydride in ionic liquids has not been studied. In this paper, the homogenous esterification of bagasse with glutaric anhydride was comparatively investigated with the isolated cellulose, hemicelluloses, and lignin in 1-allyl-3-methylimidazolium chloride (AmimCl) to reveal the reaction mechanism. Fourier transform infrared (FT-IR) indicated that the three components (cellulose, hemicelluloses, and lignin) were all involved in the esterification. The percentage of substitution (PS) of bagasse was gradually improved with the increased dosage of glutaric anhydride (10–40 mmol/g), which was primarily attributed to the increased esterification of cellulose and hemicelluloses. However, the PS fluctuation of lignin led to a decrease in the PS of bagasse at high glutaric anhydride dosage (50 mmol/g). The esterification reactivity of bagasse components followed the order of lignin > hemicelluloses > cellulose. The esterification mechanism was proposed as a nucleophilic substitution reaction. Nuclear magnetic resonance (NMR) analysis indicated that lignin aliphatic hydroxyls were prior to be esterified, and primary hydroxyls were more reactive than secondary hydroxyls in cellulose and hemicelluloses.

Surface modification of cellulose by glutaric and succinic anhydride using solvent-free grafting process: A comparative study of surface functionalization

“…Other reports in the literature also con rmed the peak at 1571 cm − 1 for stretching carboxylate groups (Ma et al 2012;Wang et al 2017). It might establish an equilibrium reaction in the presence of water.…”

“…The grafting of the cellulose surface by the anhydride groups initiates a nucleophilic attack of the more accessible hydroxyl group of cellulose to the carbonyl group of glutaric or succinic anhydride molecule. Then, the ring-opening of the as-obtained intermediate creates glutarylated or succinylated cellulose (Wang et al 2017). Glutaric anhydride has a pyranose ring structure, while succinic anhydride has a furanose ring structure.…”

On the“Staple” Effect in thed-Glucose Acetylation by Choline-Chloride Ethylene Glycol and Choline-Chloride Urea Deep Eutectic Solvents

“…This allows the calculation of the one-dimensional free energy change, known as potential of mean force (PMF). , For this study, energy minimizations were performed on the reactant ( d -glucose and acetic anhydride) and product (acetylated d -glucose at the C6 position and acetic acid) structures in various conformations. The C6 position in d -glucose (Figure d) was selected due to its susceptibility to acetic anhydride attack, as reported in several studies. ,− HBDs facilitate proton dissociation and complex formation with the reactants. However, experimental studies have shown that ethylene glycol and urea HBDs do not provide a sufficient concentration of H + to significantly alter the neutral mechanism in other reactions .…”

Nanocomposites of LLDPE and Surface-Modified Cellulose Nanocrystals Prepared by Melt Processing

“…Citric acid was also studied as a catalyst for cellulose acetylation [ 28 ]. Alternatively, CNCs can be esterified with glutaric anhydride in an ionic liquid medium [ 29 ].…”