Structural premises and laws of formation of bundled laminar associates of petroleum asphaltenes

The tendency of asphaltenes to associate, accompanied by the formation of stable supermolecular formations, to a great degree determines the methods of processing and using residual petroleum fractions. For this reason, investigators have been continuously interested in establishing the nature of binding of asphaltene molecules in these primary supermolecular formations and the possible effect on the stability of these formations. Based on the features of the chemical structure of asphaltenes, their molecules are held in bundled laminar associates primarily due to the {pi}-{pi} interaction of polyconjugated aromatic systems and the donor-acceptor reaction of heteroatomic groups. The authors fractionated asphaltenes by ion-exchange chromatography with separation of concentrates of donor- and acceptor-active compounds to determine the contribution of each of these two types of interaction. 3 refs., 2 tabs.