Asphaltenes, subfractions A1 and A2 aggregation and adsorption onto RH-SiO2 nanoparticles: Solvent effect on the aggregate size

Castillo, Jimmy; González, Ginés López; Bouyssière, Brice; Vargas, Vicmary

doi:10.1016/j.fuel.2022.125635

Cited by 7 publications

(7 citation statements)

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“…GPC−ICP−MS analyses of the asphaltene fraction of crude oil are a common technique to characterize such complex matrices. 16,23 The separation of the compounds of the sample is based on their size, with the larger compounds requiring a longer time to pass through the column. 23,45 The presence of asphaltene aggregates is detected from the presence of vanadyl porphyrins in the crude oil, which are embedded or linked to the aggregates.…”

Section: Link Between Simulations and Chromatography Resultsmentioning

confidence: 99%

“…Global properties of the obtained aggregates, such as the size and dipole moments, are described. Finally, these results are compared to the size distributions observed by gel permeation chromatography separation followed by mass spectrometry analyses using an inductively coupled plasma for sample ionization (GPC–ICP–MS) …”

Section: Introductionmentioning

confidence: 99%

“…Changing the solvent will impact the width of the hydrodynamic volume distribution. 16 Molecular dynamics simulations provide an essential tool to increase our knowledge of the behavior of the asphaltene fraction by considering, at an atomic scale, the intermolecular interactions in relation to the molecular structure. This is useful to understand the behavior of asphaltenes in solution at a nanometer scale and to link the results with experimental results on macroscopic samples.…”

Section: Introductionmentioning

confidence: 99%

“…Finally, these results are compared to the size distributions observed by gel permeation chromatography separation followed by mass spectrometry analyses using an inductively coupled plasma for sample ionization (GPC−ICP−MS). 16 2. METHODOLOGY 2.1.…”

Section: Introductionmentioning

confidence: 99%

“…Recently our group showed that asphaltenes form aggregates that are stable in various solvents, such as toluene and tetrahydrofuran (THF). Changing the solvent will impact the width of the hydrodynamic volume distribution …”

Section: Introductionmentioning

confidence: 99%

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Aggregation of Asphaltene Subfractions A1 and A2 in Different Solvents from the Perspective of Molecular Dynamics Simulations

Villegas

Vallverdu²,

Bouyssière³

et al. 2023

Energy Fuels

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The aggregation behavior of model molecules of asphaltene subfractions A1 and A2 dissolved in heptane, toluene, and tetrahydrofuran (THF) were studied using molecular dynamics simulations. The proposed asphaltene molecular models are based on previously studied structures with two new models, including a highly aromatic model with a prominent island-type molecule and another molecule with a prominent archipelago-type architecture. The aggregation mechanisms in toluene, THF, and heptane solvents were studied. The results in heptane and toluene were consistent with the solubility of asphaltenes and their subfractions in these solvents. The size of the aggregates is well-correlated with aromaticity. When considering THF, large aggregates are broken down into smaller aggregates. This could lead to the mixture of high, medium, and low molecular weight distribution bands usually observed when gel permeation chromatography (GPC) analyses are conducted on asphaltene samples in THF. The size distribution extracted from the simulations shows a bimodal distribution with profiles similar to the size distribution profiles usually found in GPC analysis for asphaltene samples in THF. The distributions of dipole moments of the aggregates against the number of molecules in aggregates were constructed in both THF and toluene and reveal that the dipole moment of the aggregates vanishes when the number of molecules increases as a result of a random structure of the aggregates. The contributions of different molecular interactions to the aggregation mechanism, such as π stacking, van der Waals, and hydrogen bonds, are described.

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