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

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.