Lignin can be an excellent source for aromatic monomers in the polymer & chemical industry. However, lignin's complex and heterogeneous structure poses a significant challenge for designing energy-efficient catalytic processes for depolymerization. During aqueous-based pretreatment, lignin fragments form aggregates and coalesce into larger droplets, and recondense on the cellulose surface, and bind with the cellulose as well as the catalyst. As many proposed catalytic depolymerization processes are solvothermal, it is essential to understand the structure and dynamics of lignin in solution. In this talk, we share our recent work on understanding the nature of lignin polymers in the solution with different solvent quality. In particular, we utilize molecular dynamics simulations to understand the effect of water models on the structure and dynamics of different model lignin oligomers (softwood and hardwood) as a function of temperature. We find that there are significant differences in the water models, especially for the dynamical properties. We will also examine the effect of solvent quality on the structural properties of model lignin oligomers. These can provide valuable insights on preferential solvation of different linkages, specifically targeting a particular linkage for the depolymerization process.

Molecular insights into structure and dynamics of lignin in the condensed phase

ACS Spring 2022

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