Lignin is one of the most abundant biopolymers on Earth, constituting about 20 to 30 percent of wood; it is one of the major waste materials of the pulp and paper industry and emerging biorefineries [1]. Utilization of lignin as a raw material for industrial chemicals would provide additional revenue streams for pulping mills and biorefineries, and especially in the case of the latter, reduce the overall cost of generating biofuel. Lignin depolymerization is the main approach to conversion of the biopolymer to value-added chemicals. It occurs by cleavage of C-C and C-O linkages between lignin units to produce low molecular weight aromatic compounds. However, the high molecular weight and three dimensional structure of lignin results in a high amount of energy to break down these linkages [4]. Electrochemical techniques applied to this problem could address issues like low selectivity toward desirable products, high energy consumption and low reaction rates.

This presentation will focus on our efforts to develop continuous electrochemical processes to convert biorefinery lignin to aromatic compounds useful to industry. We will discuss electrocatalyst development, product stream analysis techniques, and validation of a continuous process that leads to higher yield and selectivity toward useful aromatic compounds.

References:

[1] R. Behling, S. Valange, and G. Chatel., Heterogeneous Catalytic Oxidation for Lignin Valorization into Valuable Chemicals: What Results? What Limitations? What Trends?, Green Chem. (2015) 1.

[2] M.D. Kärkäs, B.S. Matsuura, T.M. Monos, G. Magallanes, C.R.J. Stephenson, Transition-metal catalyzed valorization of lignin: the key to a sustainable carbon-neutral future, Org. Biomol. Chem. (2016) 1853.

[3] B. M. Upton, A.M. Kasko, Strategies for the Conversion of Lignin to High-Value Polymeric Materials: Review and Perspective, Chem. Rev. (2016) 2275.

[4] Claudia Crestinia, Marcello Crucianellib, Marco Orlandic, Raffaele Saladinod, Oxidative strategies in lignin chemistry: A new environmental friendly approach for the functionalisation of lignin and lignocellulosic fibers, Catalysis Today 156 (2010) 8.