Catalytic valorization of lignin to monomers

RMN+ECI2D+DLA:CLO:CGEInternational audienceThe use of co-produced lignin from pulp industry or biorefinery gains nowadays a strong interest to produce aromatic compounds in a sustainable way. The valorization of those technical lignins faces their complex structure and the study of lignin conversion requires huge analytic development and careful mass and carbon balance effort during the conversion. Heterogeneous catalysts have proved to increase the liquefaction of lignin by solvolysis especially under hydrogen pressure. We report here the last results obtained for lignin valorization by catalytic hydroconversion, with a CoMo based sulfide catalyst, as a mean to depolymerize lignin and produce aromatic compounds. The originality is the use of a batch reactor opened on the gas-phase, with a continuous feeding of H2, a reflux/condensing system to remove continuously light products and water from the reacting mixture and recycle the solvent. The advanced reaction system has been demonstrated to be powerful compared to a traditional batch system previously used and allows to separate the deoxygenated monomers easily from the reaction mixture. The water formed was also successfully recovered in cold trap and quantified, and, we followed the gases formed online, which is important to get kinetic insights