Nucleophilic Cleavage of Lignin Model Compounds under Acidic Conditions in an Ionic Liquid: A Mechanistic Study

Abstract

A range of lignin model compounds were examined for their reactivity with hydrogen bromide in the ionic liquid N‐butylpyridinium triflate. It was found that the ionic liquid enabled rapid reaction at both the hydroxy and methyl ether sites of the model compounds at room temperature. Reactions at the phenyl ether moieties were more complex; rather than facilitating cleavage at these sites, alternate breakdown products that had not been seen in previous studies were observed; these products are consistent with functionalisation of the aromatic components of the model compounds.

Catalytic Processes For Lignin Valorization into Fuels and Chemicals (Aromatics)

“…Second group of processes is classified by the extension of the structural modifications induced in lignin ( Figure 4) [21]. Then, it is possible to find methods where a significant modification of lignin is produced, thus giving four types of lignin: sulfite [22], klason [23][24], alkali [25], and Kraft lignin [26][27]; and methods where mild structural modifications have been done giving lignin-type commonly named as Organosolv [28] milled wood [29], cellulolytic enzyme [30] and ionic liquid lignin [31][32], respectively. The type of manufacturing process of pulp used for papermaking determines the type of lignin industrially available, or at least the most affordable today.…”