Selection of Representative Asphaltene Molecules in an Asphalt Molecular Model Based on Quantum Chemistry and Statistical Analysis

Asphaltenes, as the most complex and strongly polar component among the four components of asphalt, have a significant impact on the macroscopic physicochemical properties of asphalt. Currently, the vast variety of molecular structures used to characterize asphaltenes increases the construction complexity of asphalt molecular models. To construct a more realistic asphalt molecular model and reduce the construction difficulty, this investigation obtains the molecular morphology, molecular polarity, and infrared spectrum indicators of 21 asphaltene molecules through quantum chemical calculations. Based on statistical analysis methods, the differences among asphaltene molecules are explored, and suggestions for selecting representative asphaltene molecules are proposed. The investigation shows that AS2, AS3, AS12, AS15, and AS17 are representative molecules that are significantly different from other asphaltene molecules. Among them, AS2, AS15, and AS17 are significantly different from the other molecules in terms of polarity and functional groups, while AS3 and AS12 are significantly different from the other molecules in terms of aromatic carbon percentage. This investigation is expected to provide valuable insights into the intrinsic relationship between the nanoscale characteristics and macroscopic properties of asphalt molecules.