Sensitivity of Asphaltene Aggregation toward the Molecular Architecture under Desalting Thermodynamic Conditions

The challenges faced by the oil and shale industries include the comprehension of the physical–chemical behavior of heavy-weight phases. These phases have a high tendency to aggregate, mainly as a result of the presence of asphaltenes, the composition of which has been fairly unclear up to now. The chemical composition of this phase is one of the driving forces behind the physical–chemical behavior in oil, and the structure–property relations of these systems are key in the development of improved refining techniques, including the design of new catalysts. In this paper, the aggregation of asphaltene molecules is studied with regard to molecular architecture and variations in the size of the aromatic core and lateral chain length using classical molecular dynamics simulations. How these characteristics are impacted by the temperature and pressure is also examined. This analysis provides a general overview of the factors that have the strongest impact on the formation and stability of nanoaggregates and clusters of nanoaggregates

Discerning Inter- and Intramolecular Vibrations of Sulfur Polyaromatic Compounds

Thiophenes are an important class of molecules in fields as diverse as petrochemistry, molecular electronics, and optoelectronics. Thiophenic submolecular motifs are thought to play a role in molecular association and nanoaggregation phenomena in both pure materials and natural and synthetic mixtures. Vibrational (infrared and Raman) spectroscopy provides the means to characterize these species. In this work far-infrared photoacoustic and low-frequency Raman spectra of a series of polycyclic aromatic hydrocarbons containing sulfur have been measured and interpreted using DFT calculations based on a perturbational-variational method coupled with potential truncation. The approach and outcomes illustrate how inter- and intramolecular vibrations for thiophenic systems in single and multicomponent mixtures can be discriminated. This work offers the perspective to search the inter- and intramolecular signatures of the main submolecular motifs and heteroelements postulated as being present in the asphaltenes