Production of propyl 4-hydroxybenzoate via selective hydrogenolysis of lignin catalyzed by Ni/MFI-ns

Abstract

Selective conversion of lignin macromolecules into aromatic monomers is of great significance but remains a major challenge. Here, we present metallic Ni supported on hierarchical multilamellar MFI nanosheets (MFI-ns), which demonstrates good efficiency in producing the versatile petrochemical ethyl 4-hydroxyhydrocinnamate (H-E) via selective cleavage of the ester linkages in lignin. With Ni₂₀/MFI-ns, an excellent H-E yield of 12.1 wt% (62.1% selectivity in the volatile products) is obtained, representing 58.7% of the theoretical yield. The synergistic interplay between enhanced mass diffusion of lignin macromolecules, NiO on the external surface of MFI-ns, Ni⁰ species and moderate Brønsted acidic sites predominantly facilitates the coupling reactions involving ester bond cleavage between pCA units and other lignin structures, esterification with ethanol, and hydrogenation of CC bonds on the side chain. In summary, this work provides a novel concept for production of value-added petrochemicals via a sustainable route by the rational design of a catalyst.