Lignin oxidation with an organic peroxide and subsequent aromatic ring opening.

The oxidation of an organosolv lignin with tert-butylhydroperoxide, initiated by titanium grafted into the lignin structure, was investigated. Titanation of reactive groups on lignin is responsible for the cross-linking of the lignin structure. IR and MAS C-13 NMR spectroscopy spectra confirmed the oxidation of the lignin structure and other pronounced structural changes. A study with guaiacol as a model compound helped to recognise that aromatic ring opening occurs under the given conditions and is catalysed by the grafted titanium. The structure of the oxidised lignin becomes less robust and therefore potentially more susceptible to be depolymerised and converted into monomeric units. (C) 2018 The Authors. Published by Elsevier B.V.