Nanoaggregates of Diverse Asphaltenes by Mass Spectrometry and Molecular Dynamics

Wang, Weiguo; Taylor, Chris; Hu, Hui; Humphries, Kathryn; Jaini, Arjun; Kitimet, Michael; Scott, Thais R.; Stewart, Zach; Ulep, Kevin John; Houck, Shannon; Luxon, Adam; Zhang, Boyi; Miller, Bill R.; Parish, Carol A.; Pomerantz, Andrew E.; Mullins, Oliver C.; Zare, Richard N.

doi:10.1021/acs.energyfuels.7b01420

Cited by 65 publications

(72 citation statements)

References 80 publications

(167 reference statements)

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“…Details of the DLS technique can be found in the relevant literature. 42,43 A multifunctional ALV 5022 laser light scattering goniometer (ALV, Asphaltene samples of ~5 mg were used for the analysis.…”

Section: Dynamic Light Scattering (Dls)mentioning

confidence: 99%

“…The heteroatoms (N, O and S) embedded in the aromatic rings of asphaltenes could strengthen the aromatic interaction between asphaltenes, 17,57 which is considered to be the dominant driving force for asphaltene aggregation. 17,43,57,58 The presence of heteroatoms increases the polarity of asphaltenes and hence enhances the -electron cloud density of aromatic rings, thus contributing to stronger -stacking interactions between the polyaromatic cores of asphaltenes. In addition, heteroatoms along the aliphatic side chains of asphaltenes also play a significant role in the aggregation of asphaltenes through polar interactions.…”

Section: Interaction Forces Between Fractionated Asphaltenes In Organmentioning

confidence: 99%

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Interactions of Asphaltene Subfractions in Organic Media of Varying Aromaticity

Qiao

Harbottle

et al. 2018

Energy Fuels

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Whole asphaltenes were fractionated by extended-saturates, aromatics, resins and asphaltenes (E-SARA) analysis into four asphaltene subfractions: toluene-extracted interfacially active asphaltenes (T-IAA), toluene-extracted remaining asphaltenes (T-RA), heptol 50/50-extracted interfacially active asphaltenes (HT-IAA), and heptol 50/50extracted remaining asphaltenes (HT-RA). The aggregation kinetics of fractionated asphaltenes measured by dynamic light scattering (DLS) showed that decreasing solvent aromaticity promoted asphaltene aggregation for all subfractions. In a given solvent, T-IAA exhibited the strongest aggregation tendency, followed by HT-IAA, then T-RA and

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Section: Dynamic Light Scattering (Dls)mentioning

confidence: 99%

Section: Interaction Forces Between Fractionated Asphaltenes In Organmentioning

confidence: 99%

Interactions of Asphaltene Subfractions in Organic Media of Varying Aromaticity

Qiao

Harbottle

et al. 2018

Energy Fuels

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“…The faculty published 2 peer‐reviewed books, [ 238,239 ] 9 peer‐reviewed book chapters, [ 240–248 ] and 115 peer‐reviewed research papers. [ 249–363 ] This comes to 1.6 peer‐reviewed products/faculty/year during the 3‐year grant period, which is 3.2 times the rate of publication for natural science faculty at PUIs. [ 46 ]…”

Section: Research Accomplishments (Intellectual Merit) and Transformamentioning

confidence: 99%

Twenty years of exceptional success: The molecular education and research consortium in undergraduate computational chemistry (MERCURY)

Shields

2020

Int J of Quantum Chemistry

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The molecular education and research consortium in undergraduate computational chemistry (MERCURY) consortium, established in 2000, has contributed greatly to the scientific development of faculty and undergraduates. The MERCURY faculty peer-reviewed publication rate from 2001 to 2019 of 1.7 papers/faculty/year is 3.4 times the rate of the physical science faculty at primarily undergraduate institutions. We have worked with over 1000 students on research projects since 2001, and 75% of our undergraduate research students have been under-represented in chemistry, either female or students of color. Approximately half of our alumni attend graduate school for the purpose of obtaining advanced degrees in STEM fields, and two-thirds are female and/or students of color. We have had more than 1600 attendees at 18 MERCURY conferences, including 111 invited speakers, 61 of whom have been female and/or faculty of color. In this paper, the research accomplishments, transformational outcomes, and scientific productivity of the MERCURY faculty are highlighted.

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“…23 The use of quantum-chemical calculations to obtain partial charges is a way to represent the chemical features of the asphaltenes in the atomistic simulations. 23,39,40 The replacement of groups of asphaltene atoms with “grains” is a way to increase the available time and length scales in comparison with simulations based on the atomistic models. 41−45 The coarse-graining procedure significantly simplifies the chemistry of the asphaltenes and their interactions.…”

Section: Introductionmentioning

confidence: 99%

Toward Predictive Molecular Dynamics Simulations of Asphaltenes in Toluene and Heptane

et al. 2019

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The conventional definition of asphaltenes is based on their solubility in toluene and their insolubility in heptane. We have utilized this definition to study the influence of partial charge parametrization on the aggregation behavior of asphaltenes using classical atomistic molecular dynamics simulations performed on the microsecond time scale. Under consideration here are toluene- and heptane-based systems with different partial charges parametrized using the general AMBER force field (GAFF). Systems with standard GAFF partial charges calculated by the AM1-BCC and HF/6-31G*(RESP) methods were simulated alongside systems without partial charges. The partial charges implemented differ in terms of the resulting electrical negativity of the asphaltene polyaromatic core, with the AM1-BCC method giving the greatest magnitude of the total core charge. Based on our analysis of the molecular relaxation and orientation, and on the aggregation behavior of asphaltenes in toluene and heptane, we proposed to use the partial charges obtained by the AM1-BCC method for the study of asphaltene aggregates. A good agreement with available experimental data was observed on the sizes of the aggregates, their fractal dimensions, and the solvent entrainment for the model asphaltenes in toluene and heptane. From the results obtained, we conclude that for a better predictive ability, simulation parameters must be carefully chosen, with particular attention paid to the partial charges owing to their influence on the electrical negativity of the asphaltene core and on the asphaltenes aggregation.

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Nanoaggregates of Diverse Asphaltenes by Mass Spectrometry and Molecular Dynamics

Cited by 65 publications

References 80 publications

Interactions of Asphaltene Subfractions in Organic Media of Varying Aromaticity

Interactions of Asphaltene Subfractions in Organic Media of Varying Aromaticity

Twenty years of exceptional success: The molecular education and research consortium in undergraduate computational chemistry (MERCURY)

Toward Predictive Molecular Dynamics Simulations of Asphaltenes in Toluene and Heptane

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