Metal Catalyst-Free Oxidative C-C Bond Cleavage of a Lignin Model Compound by H2O2 in Formic acid

Selective cleavage of the beta-O-4 ether bond of lignin to produce aromatics is one of the most important topics for the sustainable production of chemicals from biomass. A simple system has been developed for C-alpha-C-beta bond cleavage of a beta-O-4 ketone-structured lignin model compound (LMC) by H2O2 in formic acid under metal catalyst-free conditions. By using this simple system, with H2O2, formic acid, and mineral acid catalyst, over 90 % product yield is achieved in 6 h at room temperature. The reaction proceeds through the classic Baeyer-Villiger oxidation and in situ-generated performic acid serves as the key oxidant. The cleavage of alcoholic LMCs by using the presented method in a two-step process is also demonstrated.