Abstract: Resin in Fengcheng heavy crude was separated by silica gel column chromatography. The compositions and structures of the resin were characterized by elemental analysis, FT-IR, NMR and XPS. The average structural parameters and average molecular formulas of the resin were determined by 1H NMR/IR method. The results showed that the resin in Fengcheng heavy crude is polar molecules containing heterocyclic aromatics, n-alkanes and N, O and S atoms. Oxygen atoms exist mainly in the form of ether oxygen and N atoms are mostly in the form of pyrrole and pyridine. The average molecular weight of the resin is 3 773, the number of average structural units (n) is 6.57 and the average structure unit formula is C39H55O2N. In addition, the aggregation behaviors of the resin in heptane and toluene were also discussed by molecular dynamics simulation method. It is showed that the resin can form stable aggregate system in heptane, however toluene is good for diffusion of resin molecules.

Key words: resin, average structural parameters, average structure unit formula, molecular dynamics, heavy oil