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In this paper the aggregation of asphaltenes is studied for two asphaltene molecule families, namely PA3 and CA22 analogues, based on the work of Schuler et al. (JACS, 2015, 137, 31, 9870). The chemical characteristics of these molecules were screened by changing the heteroatoms on the backbone and the lateral chain-ends. These molecules were mixed together with different relative concentrations and for the first time the aggregation of different asphaltenes was determined using molecular dynamics simulations (MDS). The results show that the interaction energies vary for different heteroatom arrangement within a given structure and depend on the type of asphaltene. Moreover, we showed that the chain-ends have a crucial role on this phenomenon.

We present molecular dynamics simulations (MDS) for interpreting the molecular aggregation of four different asphaltene molecular models. These simulations are based on recent small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS) experiments from Eyssautier and co-workers [

Asphaltene aggregation is a subject under vivid discussion: There are several parameters one needs to determine before its behavior can be mastered and better target solutions can be tailored. The nature of asphaltene aggregation (colloidal or supramolecular) and the role of solvents and their mixtures are among the least understood parameters in asphaltene science. 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.

The presence of metalloporphyrins in crude oil has been known by many years now but their role on the physical-chemical properties of petroleum fluids, such as the aggregation of the high-molecular weight phases, remains unknown. In this paper, these properties are studied using different molecular modeling techniques (Molecular Dynamics, Semi-empirical PM7 and Density Functional Theory). This combined methodology allowed us characterizing the nature of these interactions, how it dominates the electronic structure of the stacked molecules and what is their participation on the formation of the nano-, microand macro-aggregates.