The modification of lignocellulose with cyclic anhydrides could confer stronger hydrophilic properties to lignocellulose, which could be used in many industrial fields. To elucidate the modification mechanism of lignocellulose, bagasse was phthalated comparatively with its three main components in 1‐allyl‐3‐methylimidazolium chloride (AmimCl) using 4‐dimethylaminopyridine as catalyst and phthalic anhydride as acylation reagent in the present study. From FT‐IR and 2D HSQC analyses, the skeleton of bagasse and the fractions were not significantly changed during phthalation in AmimCl. 2D HSQC results suggested that the reactive hydroxyls in bagasse were partially phthalated, and the reactivity of the hydroxyls in anhydroglucose units followed the order C‐6 > C‐2 > C‐3. Similarly, the reactivity order of hydroxyls in anhydroxylose units was C‐2 > C‐3. For lignin, the predominant diesterification occurred during the homogeneous modification, and both aliphatic and aromatic hydroxyls were phthalated. The reactivity order of phenolic hydroxyls was S‐OH > G‐OH > H‐OH, which was distinct from that without catalyst. In addition, it was found that the thermal stability of phthalated bagasse was affected by the disruption of cellulose crystallinity and the degradation of components. The thermal stability of the phthalated bagasse decreased upon chemical modification and regeneration.
Part of the book: Biomass Volume Estimation and Valorization for Energy