ReaxFF Reactive Force Field for Molecular Dynamics Simulations of Lignite Depolymerization in Supercritical Methanol with Lignite-Related Model Compounds

To investigate the detailed mechanisms for lignite methanolysis, we used ReaxFF reactive force field to perform a series of molecular dynamics simulations (MDSs) on a unirnolecular model compound. The alpha-O-4 and beta-O-4 types of lignite-related model compounds were selected as representatives Of linkages in lignites. The reaction products predicted by ReaxFF MDSs are consistent with those from experimental results reported. The initiation reaction observed in ReaxFF MDSs involving the ether linkage cleavage and methanol participation closely matches the results observed from previously reported experiments. The agreement of these results with available experimental observations demonstrates that ReaxFF MDSs can give an atomistic description of the initiation mechanism for methanolysis and provide useful insights into the complicated reaction processes.