Hydrogenolysis of biorefinery corncob lignin into aromatic phenols over activated carbon-supported nickel†
Lignin is the most abundant renewable resource for production of bio-aromatic chemicals. However, the catalytic depolymerisation of lignin into phenolic monomers is still challenging due to its intrinsic heterogeneity. Herein, we report that Ni/AC can serve as an efficient and stable catalyst in the hydrogenolysis of biorefinery corncob lignin into low-molecular-weight aromatics. This catalyst showed high activity towards reductive fragmentation of hydroxycinnamic esters and β-O-4 linkages through scission by reaction with hydrogen to cleave C–O bonds. Under optimal conditions, this catalytic system produced 31% selectivity towards unsaturated substituents containing coumarate and ferulate derivatives, which afforded mono-aromatic phenols (up to 12.1 wt%) derived from hydroxycinnamic acid moieties (8.1 wt%) and β-O-4 units (2.7 wt%), respectively. The use of non-precious metals to develop highly efficient heterogeneous catalysts makes this approach of great interest in the production of aromatic phenols for the valorisation of industrial lignin.