Insights of asphaltene aggregation mechanism from molecular dynamics simulation

Leon, Jennifer De; Hoyos, Bibian; Cañas-Marín, Wilson A.

doi:10.15446/dyna.v82n189.41963

Cited by 13 publications

(3 citation statements)

References 12 publications

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“…The PA3 molecule properties were evaluated to compare them with the typical asphaltene reported values, as seen in Table 2. The solubility parameter was calculated as explained by De Leoń et al 61 According to the molecular weight (484.6 Da for the molecules without heteroatoms), the molecule has a lower value than the commonly reported 600−700 Da. 62 The solubility parameter of the CCC molecule is below the expected and reported value for asphaltene molecules, even below the solubility parameter of toluene (∼18.2 MPa 1/2 ) and near to the n-heptane solubility parameter (∼15.3 MPa 1/2 ).…”

Section: Resultsmentioning

confidence: 99%

Molecular Dynamics Study of the Aggregation Behavior of Polycyclic Aromatic Hydrocarbon Molecules in n-Heptane–Toluene Mixtures: Assessing the Heteroatom Content Effect

et al. 2021

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This study is focused on evaluating the aggregation behavior of four asphaltene molecules (PA3-type) dissolved in three different solvents. Hence, solution models composed of asphaltenes dissolved in toluene, n-heptane, and mixtures of n-heptane and toluene (known as heptol), were evaluated with molecular dynamics (MD) simulations. For MD calculations, four PA3-type structures were chosen to evaluate the effect of the location of one heteroatom in the polyaromatic core on the aggregation behavior. The first structure consists of only a CH structure, the second has sulfur, the third has nitrogen, and the last one contains oxygen. The heteroatom was replaced in the same location in one of the five-membered rings in the center of the molecule to test the different chemical effects induced by these heteroatoms. Molecules with the heteroatoms showed a higher aggregation tendency in n-heptane than in heptol-50 and toluene, with an average size of 12.8, 6.2, and 2.4 molecules per aggregate, respectively, whereas the PA3 molecule with no heteroatom forms less and smaller aggregates. The inclusion of only one heteroatom increases the polarity and the planarity of the molecule, increasing the attractive interaction energies (140−160% in n-heptane) and the overall aggregation tendency. The molecule with the sulfur heteroatom forms bigger and more stable aggregates than molecules with oxygen and nitrogen. In conclusion, the inclusion of heteroatoms in the PA3 structure increases the polarity and planarity of the molecule, improving the aggregation tendency in all solvents, notoriously in n-heptane.

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Section: Resultsmentioning

confidence: 99%

Molecular Dynamics Study of the Aggregation Behavior of Polycyclic Aromatic Hydrocarbon Molecules in n-Heptane–Toluene Mixtures: Assessing the Heteroatom Content Effect

et al. 2021

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“…30 From the Archipelago model perspective, the mechanisms for nanoaggregation are not well-defined, but it is thought that heteroatoms and the diversity of the molecular structures present permit aggregation among molecules. 31 Acid−base interactions, metal complexes, and hydrogen bonding play important roles. 32 The distinction between nanoaggregation and flocculation is not delineated within this conceptual framework.…”

Section: Introductionmentioning

confidence: 99%

Gold Core Nanoparticle Mimics for Asphaltene Behaviors in Solution and at Interfaces

et al. 2016

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Asphaltenes are a poorly defined class of self-assembling and surface active molecules present in crude oils. The nature and structure of the nanoaggregates they form remain subjects of debate and speculation. In this exploratory work, the surface properties of asphaltene nanoaggregates are probed using electrically neutral 5 nm diameter gold-core nanoparticles with alkyl, aromatic, and alkanol functionalities on their surfaces. These custom synthesized nanoparticles are characterized, and their enthalpies of solution at near infinite dilution and the interfacial tensions of solutions containing these nanoparticles are compared with the corresponding values for Athabasca pentane asphaltenes. The enthalpies of solution of these asphaltenes in toluene, heptane, pyridine, ethanol, and water are consistent with the behavior of gold-alkyl nanoparticles. The interfacial tension values of these asphaltenes at toluene–water and (toluene + heptane)–water interfaces are consistent with the behavior of gold-biphenyl nanoparticles as are the tendencies for these asphaltenes and gold-biphenyl nanoparticles to “precipitate” in toluene + heptane mixtures. Gold-alkyl nanoparticles are minimally surface active at toluene–water and (toluene + heptane)–water interfaces and remain dispersed in all toluene + heptane mixtures. The behavior of these asphaltenes in solution and at interfaces is inconsistent with the behavior of gold-n-alkanol nanoparticles. The outcomes of this formative work indicate potential roles for aromatic submolecular motifs on aggregate surfaces as a basis for interpreting asphaltene nanoparticle flocculation and interfacial properties, while alkyl submolecular motifs on aggregate surfaces appear to provide a basis for interpreting other aspects of asphaltene solution behavior. A number of lines of inquiry for future work are suggested.

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“…[8][9][10][11][12][13][14][15][16][17][18] Sodium alkyl benzene sulfonates have also been investigated via simulation for several years. Mao 13 and others studied the effects of SDS, SDBS, LAS and LABS on the morphology of calcium sulfate hemihydrate (HH) by experiment and MD simulation.…”

Section: Introductionmentioning

confidence: 99%

Interfacial assignment of branched-alkyl benzene sulfonates: A molecular simulation

Liu

Wei

et al. 2015

AIP Advances

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Insights of asphaltene aggregation mechanism from molecular dynamics simulation

Cited by 13 publications

References 12 publications

Molecular Dynamics Study of the Aggregation Behavior of Polycyclic Aromatic Hydrocarbon Molecules in n-Heptane–Toluene Mixtures: Assessing the Heteroatom Content Effect

Molecular Dynamics Study of the Aggregation Behavior of Polycyclic Aromatic Hydrocarbon Molecules in n-Heptane–Toluene Mixtures: Assessing the Heteroatom Content Effect

Gold Core Nanoparticle Mimics for Asphaltene Behaviors in Solution and at Interfaces

Interfacial assignment of branched-alkyl benzene sulfonates: A molecular simulation

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