Selective hydrogenolysis of phenols and phenyl ethers to arenes through direct C–O cleavage over ruthenium–tungsten bifunctional catalysts

Abstract

Direct hydrogenolysis of the aromatic C_sp²–O bonds in both phenols and phenyl ethers to form arenes selectively is a core enabling technology that can expand greatly the scope of chemical manufacture from biomass. However, conventional hydrogenolysis of phenols typically led to aromatic ring saturation instead of the cleavage of the C_sp²–O bonds. Herein, we report a recyclable Ru–WO_x bifunctional catalyst that showed high catalytic activities for the hydrogenolysis of a wide range of phenols and phenyl ethers, including dimeric lignin model compounds and the primitive phenols separated from pyrolysis lignin, to form arenes selectively in water. Preliminary mechanistic studies supported that the reactions occurred via a direct cleavage of the C_sp²–O bonds and the concerted effects of the hydrogenating Ru sites and the Lewis acidic W sites are the key to such an unusual reactivity.