(97a) Adsorption Free Energy Surfaces of Lignin Dimers over Zeolite Nanosheets in Solution
AIChE Annual Meeting
2022
2022 Annual Meeting
Catalysis and Reaction Engineering Division
Catalysis in Liquid Media I: Catalysis for Biomass Conversion in Liquid Phase
Monday, November 14, 2022 - 12:30pm to 12:50pm
Lignin depolymerization into aromatic chemicals and fuels has gained significant attention due to lignin's abundance in nature.
Although lignin shows potential as a renewable feedstock, it is difficult to selectively cleave the stable aryl-ether and carbon-carbon linkages.
Zeolite nanosheets (2D zeolites) show promise as a catalyst for lignin depolymerization due to their enhanced surface activity and low diffusion barriers for high molecular weight compounds like lignin. Previous work has shown that solvothermal conditions influence the binding modes of β-O-4 linkages on the surfaces of MWW-2D surfaces. However, it is unknown how the choice of solvent impacts the binding modes of linkages other than β-O-4, and how Brønsted acid zeolite nanosheets influence the binding modes.
In this work, we use ab initio molecular dynamics (AIMD) to model the adsorption lignin dimers over MWW zeolite nanosheets in different solvothermal environments. The solvents included in this study are formic acid, tetralin, water, and methanol. Calculations performed with pure silica MWW and including Brønsted acidity in the framework are also performed. Biased AIMD simulations are performed with metadynamics to estimate the adsorption free energy surface of lignin binding to the catalyst. Current work suggests that hydrogen bonds between the terminal silanol groups on the zeolite are mainly responsible for the β-O-4 linkage binding to the surface.
Although lignin shows potential as a renewable feedstock, it is difficult to selectively cleave the stable aryl-ether and carbon-carbon linkages.
Zeolite nanosheets (2D zeolites) show promise as a catalyst for lignin depolymerization due to their enhanced surface activity and low diffusion barriers for high molecular weight compounds like lignin. Previous work has shown that solvothermal conditions influence the binding modes of β-O-4 linkages on the surfaces of MWW-2D surfaces. However, it is unknown how the choice of solvent impacts the binding modes of linkages other than β-O-4, and how Brønsted acid zeolite nanosheets influence the binding modes.
In this work, we use ab initio molecular dynamics (AIMD) to model the adsorption lignin dimers over MWW zeolite nanosheets in different solvothermal environments. The solvents included in this study are formic acid, tetralin, water, and methanol. Calculations performed with pure silica MWW and including Brønsted acidity in the framework are also performed. Biased AIMD simulations are performed with metadynamics to estimate the adsorption free energy surface of lignin binding to the catalyst. Current work suggests that hydrogen bonds between the terminal silanol groups on the zeolite are mainly responsible for the β-O-4 linkage binding to the surface.