Abstract
In this study, average structural characteristics of amber were researched and used as an example to establish the three-dimensional (3D) average structure of resin. Two coal samples containing solid amber were collected from Fushun and Hunchun in Northeast China, from which pure amber samples were separated and resin was extracted. Solid-state nuclear magnetic resonance ((13)C NMR) spectroscopy was used to obtain structural information of amber, and matrix-assisted laser desorption ionization time-of-flight mass spectrometry was performed on the resins to determine their molecular mass. The results of these studies revealed that the average structure of amber was dominated by cycloalkane, with a small amount of aromatic carbon, and there were almost no aliphatic chains in the structure. The molecular masses of the compounds in the resin were mainly in the range 99-750 Da, and the average molecular mass was ∼370 Da. To characterize the resin chemical structure, two 3D molecular models based on density functional theory were established taking amber as the example, and the relevant molecular bond energies were calculated. Based on these models, the interactions among the components in oil were studied, and the binding energies of the different molecules were calculated. In summary, in this study, amber was used as a medium to establish an accurate molecular model of resin and proved that compared to hydrocarbon compounds, resin molecules were more likely to interact with bitumen.