Selective Hydrodeoxygenation of Lignin-Derived Phenols to Aromatics Catalyzed by Nb2O5-Supported Iridium

The dominating catalytic approach to aromatic hydrocarbons from renewables, deoxygenation of phenol-rich depolymerized lignin bio-oils, is hard to achieve: hydrodeoxygenation (HDO) of phenols typically leads to the loss of aromaticity and to non-negligible fractions of cyclohexanones and cyclohexanols. Here, we report a catalyst, niobia-supported iridium nanoparticles (Ir@Nb2O5), which combines full conversion in the HDO of lignin-derived phenols with appreciable and tunable selectivity for aromatics (25-95%) under mild conditions (200-300 degrees C, 2.5-10 bar of H-2). A simple approach to the removal of Bronsted-acidic sites via Hiinig's base prevents coking and allows reaction conditions (T > 225 degrees C, 2.5 bar of H-2), promoting high yields of aromatic hydrocarbons.

Automated summary

A catalyst of niobia-supported iridium nanoparticles (Ir@Nb2O5) is reported, which can achieve full conversion of lignin-derived phenols to aromatics under mild conditions with appreciable selectivity.