Intermolecular Forces in Aggregates of Asphaltenes and Resins

ABSTRACT In order to determine the forces acting in the asphaltene and resin molecular aggregates, an analysis of the origin of the intermolecular interactions in organic molecules was made. The results showed that the forces present in the aggregates of asphaltenes and resins were only those originated in the van der Waals, Coulombic (electrostatic), charge transfer and induction plus the exchange–repulsion interaction. No other forces were found to be significant in these aggregates that are formed by molecules containing well-known atomic groups. Molecular orbital calculations in resins and model asphaltene suggested that charge transfer is small or negligible in their aggregates. Although the H bonds present could be quite strong, other intermolecular interactions should not be disregarded in the analysis of the energy of their aggregates. Acknowledgments