Enhanced Demethylation of Aromatic Ether to Phenol Over Hydrotalcite-Derived Ni9s8-Al2o3 Catalyst

Abstract

The production of phenol from lignin or its model compounds, instead of cumene oxidation is very interesting from the viewpoint of sustainability and economics. The selective demethylation of anisole was an efficient route to produce phenol. In this work, we demonstrated the fabrication of Ni9S8 nanoparticles on Al2O3 matrix by a facile in situ sulfuration of NiAl hydrotalcite and announced that Ni9S8 can serve as efficient active site for the demethylation of anisole for the first time. The as-designed Ni9S8-Al2O3 catalyst exhibited a hierarchical morphology with a high particle density and high dispersion, affording a 95.6% yield of phenol in the demethylation of anisole under relative milder reaction temperature (270 oC) when compared to the reported state-of-the-art results. We found that the Ni9S8-Al2O3-4/1 with modest S vacancies and particle size resulting in strongest electronic transfer from Ni3+ to Al2O3 in Ni9S8-Al2O3 interface, which can an not only favor the C-O cleavage but also accelerate the hydrogen dissociation, thus demonstated an outstanding activity in demethylation of anisole to phenol.

Keywords: Anisole, Demethylation, Phenol, Hydrotalcite, Ni9S8