Asphaltene aggregation studied by molecular dynamics simulations: role of the molecular architecture and solvents on the supramolecular or colloidal behavior

Hugo Santos Silva (1) , A. Alfarra , Germain Vallverdu (2) , Didier Bégué (2) , Brice Bouyssière (2) , Isabelle Baraille (2)

1 Instituto de Física
2 IPREM - Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux

This paper addresses molecular dynamic simulations to correlate the aggregation properties of asphaltenes, their molecular structure and the concentration of these solvents. We show that the formation of the nanoaggregate depends, primarily, on the size of the conjugated core and on the eventual presence of polar groups capable of forming H-bonds. Heteroatoms on the conjugated core do not change their shape or type of aggregation but may induce stronger π−π interactions. The macroaggregation formation depends upon the length of the lateral chains of asphaltenes and also on the presence of polar groups at its end. Moreover, n-heptane and water may interact selectively with asphaltenes in function of their molecular architecture. Given this fact and the aggregation behavior observed, we advocate toward the assumption that a colloidal behavior of asphaltenes might be a particular case of a more general model, based on a supramolecular description.

Mots clés: Asphaltenes Molecular dynamics Aggregation Heavy oil; Asphaltenes; Molecular dynamics; Aggregation; Heavy oil

Domaines: Chimie théorique et/ou physique

Hugo Santos Silva, A. Alfarra, Germain Vallverdu, Didier Bégué, Brice Bouyssière, et al.. Asphaltene aggregation studied by molecular dynamics simulations: role of the molecular architecture and solvents on the supramolecular or colloidal behavior. Petroleum Science and Technology, 2019, 16 (3), pp.669-684. ⟨10.1007/s12182-019-0321-y⟩. ⟨hal-02172587⟩