Estimation of Noncovalent Interactions in Aromatic Unit Clusters of Coal and Asphaltene Using Molecular Simulation

摘要

For model structures of coal extract and petroleum asphaltene, molecular mechanics and molecular dynamics calculations showed that they form aggregated structures through several noncovalent interactions, such as aromatic stacking, and electrostatic and van der Waals interactions. The aggregation energy between the aromatic unit clusters, and the contribution of each interaction (heteroatoms, alkyl chains, hydrogen bonds and aromatic stacking) to the total aggregation energy were computationally estimated. For the model structure of asphaltene, the average contribution rate of aromatic stacking interactions was the largest of all noncovalent interactions, 49.9 %, while those of heteroatoms, alkyl chains, and hydrogen bonds were 20.2, 27.2 and 2.7 %, respectively, although the hydrogen bonds had a large effect locally at the hydrogen-bond site. Difference in contribution of each noncovalent interaction in coal and asphaltene is presented.