Iron porphyrin catalyzed oxidation of lignin model compounds: oxidation of phenylpropane and phenylpropene model compounds

Abstract

The oxidation of 1-(4-ethoxy-3-methoxyphenyl)propane (2) and 1-(4-ethoxy-3-methoxyphenyl)propene (3) by meso-tetra(2,6-dichloro-3-sulphonatophenyl)porphyrin iron chloride (TDCSPPFeCl, 1) and tert-butylhydroperoxide (t-BuOOH) are discussed. In addition to a C α -hydroxylation product, demethoxylation and direct aromatic ring cleavage products were found in the oxidation of 2. When 3 was oxidized by 1 and t-BuOOH in aqueous acetonitrile, an acetonitrile-incorporated product was found. A mechanism for the oxidation of 3 is proposed. Keywords: lignin, ligninase, iron porphyrin, model, degradation.