Lignocellulosic biomass is rich with useful aromatics for chemicals and energy sources; thus a renewable source of energy. Lignin, a complex polymer of valuable phenols, is the 2nd abundant constituent of this biomass. It is processed as a black liquor waste in large amounts from the pulp and paper industries (Kraft lignin) where only 2% is commercialized and 98% are burnt as low cost fuel. However, the cheap and easily accessible aromatic kraft lignin can be a renewable precursor for phenolic building blocks; thus kraft lignin selective degradation is favored. Among different conversion process of lignin, catalytic hydrogenolysis is preferred as it is less dangerous than oxidation, higher atom efficiency, and produces less char which fits the green chemistry principle. Hence, this research focused on the degradation of kraft lignin via heterogeneous catalytic hydrogenolysis using homemade Ni nanoparticle composites. The results illustrate successful synthesis of Ni nanoparticles supported on a salt melt nitrogen doped carbon (Ni–NDC) with a hierarchical porosity applied as heterogeneous catalyst for the degradation of phenolic kraft lignin. They revealed that Ni–NDC is more efficient compared to Ni nanoparticles deposited on an N-free carbon support, prepared with similar porosity features (Ni–C) and to Ni nanoparticles deposited on a benchmark commercial carbon (Ni–Cref). Moreover, the structural nitrogen in the NDC improves the stability of the catalyst, its efficiency, and activity. Finally, the efficiency of these materials was compared for reactions performed in batch and flow reactors, highlighting the effect of the reactor setup on the stability of the recovered catalysts.

Efficiency of Ni-nanoparticles deposited on a hierarchically porous carbon doped with nitrogen for kraft lignin hydrogenolysis in flow and batch systems

253rd National Meeting (2017)

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