Hydrogenolysis of lignin and Lignin-based molecules catalyzed by nickel and Sc(OTf)3

Abstract

Renewable aromatic carbon sources and their transformation into value-added chemicals represent one of the most promising approaches of sustainable development. Here, we prepared and characterized nickel catalysts and evaluated their activity in transfer hydrogenolysis reactions using formic acid as hydrogen donor, finding excellent activity and high selectivity to CO bond cleavage in lignin and lignin model compounds using water/ethanol or propylene carbonate as solvents. Particularly, a nickel catalyst named Ni-1, was used in the guaiacylglycerol-β-guaiacyl hydrogenolysis to selectively obtain guaiacol and isoeugenol. Thus, in the case of Ni-1 (NiIINx) we found that small clusters and nanoparticles of 3 –5 nm diameters coexist in the material. Further, the Sc(OTf)3 Lewis acid (LA) successfully promoted the CO bond cleavage of 1-(o-tolyloxy)propan-2-ol to obtain guaiacol. Additionally, we describe the synthesis of benzodioxanes catalyzed by scandium triflate from 1-(o-tolyloxy)propan-2-ol as product of the propylene carbonate decarboxylation catalyzed by ZIF-8.

Keywords

• Catalytic hydrogenolysis
• Nickel catalyst
• Lewis acid
• C–O bond cleavage
• Formic acid
• Kraft lignin