2 research outputs found
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