Molecular Size of Asphaltene Solubility Fractions

Groenzin, Henning; Mullins, Oliver C.; Eser, Semih; Mathews, Jonathan P.; Yang, Mingzheng; Jones, A. Daniel

doi:10.1021/ef010239g

Cited by 139 publications

(156 citation statements)

References 22 publications

(36 reference statements)

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“…For instance Small-Angle X-ray and Neutron Scattering (SAXS and SANS) experiments were generally performed at concentrations close to 10 g.L -1 for asphaltenes dissolved in model solvents 17,18,[48][49][50][51] . It was not until 1999, using techniques such as fluorescence depolarization technique [52][53][54][55][56] , fluorescence correlation spectroscopy [57][58][59] and mass spectrometry 60,61 that reliable results, accounting for the molecular aggregation at higher concentrations, became available. These results have shown that typical mean molecular weights of asphaltenes were ∼750 g.mol -1 with a factor of 2 in the width of the molecular weight distribution.…”

Section: Structurementioning

confidence: 99%

Model molecules mimicking asphaltenes

Sjöblom

Simon

2015

Advances in Colloid and Interface Science

161

132

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Section: Structurementioning

confidence: 99%

Model molecules mimicking asphaltenes

Sjöblom

Simon

2015

Advances in Colloid and Interface Science

161

132

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“…Several different methods have been applied to determine the molecular mass of asphaltenes and/or their different aggregation states: vapour pressure osmometry [16], small-angle neutron and X-ray scattering (SANS and SAXS, see below), mass spectrometry [8][9][10][11][12][13][14][15][16], fluorescence depolarisation measurements [9,10], and NMR [17,18]. Mass results are different in regard to the concentration range and the measurement technique.…”

Section: Structural Information From Scattering Measurementsmentioning

confidence: 99%

“…Despite the small number and limited range of data, a regression analysis yields the following relationships: (19) [η] = 0.049M w 0.41 (20) A 2 = 0.0129M w -0.55 (21) As previously explained in Section 1, all these power law type relations could be related to mass fractal organisation of the aggregates. Comparison of relations (19,20,21) with Equations (9,16,10) large q values, is a very strong indication of the fractal nature of asphaltene aggregates. It can be concluded that asphaltene solutions in toluene are described as a polydispersion of solvated aggregates characterised by a fractal dimension close to 2.1.…”

Section: Viscositymentioning

confidence: 99%

“…Chemical analysis indicates that this fraction concentrates the most aromatic and polar molecules [7]. The determination of asphaltene molecular weight has been a subject of intense debate and it is now generally agreed that values are 500 to 1000 g.mol -1 [8,10]. Furthermore, most of the molecules have a central aromatic part with peripheral aliphatic or naphthenic moieties [8,10].…”

Section: Introductionmentioning

confidence: 99%

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Relation between Nanoscale Structure of Asphaltene Aggregates and their Macroscopic Solution Properties

Barré

Jestin

Morisset

et al. 2009

Oil & Gas Science and Technology - Rev. IFP

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Résumé -Relation entre nanostructure des agrégats d'asphaltène et les propriétés macroscopiques de leur solution -Certaines propriétés particulières de bruts pétroliers sont attribuées à leur fraction la plus dense, lourde et polaire : les asphaltènes. La compréhension de l'origine de ces propriétés repose sur une description structurale fine de ces fractions. Nous présentons une caractérisation des solutions d'asphaltène, à l'échelle du nanomètre, basée sur de nouvelles ou récentes expériences de diffusion de rayonnement (rayons X ou neutrons) à partir desquelles des paramètres structuraux des agrégats d'asphaltène (R g , M w et A 2 ) sont déduits. La dépendance de ces paramètres est compatible avec un modèle d'agrégats de type fractal de masse. Ce modèle rend compte de toute la variété de propriétés macroscopiques de ces solutions. En particulier, la prise en compte de l'aspect solvaté des agrégats permet de prédire la viscosité de solutions d'asphaltène en fonction de leur concentration. D'autre part, les asphaltènes s'adsorbent aux interfaces liquide-liquide et liquide-solide et forment des monocouches dont l'épaisseur est du même ordre de grandeur que la taille des agrégats de la solution. L'analyse des isothermes d'adsorption, les expériences de réflectivité des neutrons ainsi que les expériences de diffusion des neutrons en conditions d'extinction de contraste, mettent en évidence une densification des agrégats d'asphaltène dans la couche adsorbée relativement à leur état solvaté dans le volume. Enfin, la résultante des interactions attractives/répulsives entre agrégats peut être reliée à la stabilité relative d'émulsions d'eau dans l'huile et à la stabilité d'effluents d'hydroconversion. Cette approche de mise en relation entre structure et propriété permet d'asseoir et de justifier le modèle de fractal de masse qui est discuté. Abstract

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“…Generally, hydrodynamic properties such as intrinsic viscosity [4,5], diffusion coefficient [3,[6][7][8][9][10][11], and interface or surface tension [12][13][14] are used to elucidate information about the shape and size of heavy oil molecule in solution. In recent years, with the fast development of computer technology, molecular simulation has been applied into characterizing the shape and size of heavy oil molecules [15,16].…”

Section: Introductionmentioning

confidence: 99%

Molecular size characterization of heavy oil fractions in vacuum and solution by molecular dynamic simulation

Ren

Chen

Yang

et al. 2010

Front. Chem. Eng. China

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Two kinds of heavy oils were fractionated into eight fractions by Liquid-Solid Adsorption Chromatography, respectively, and samples were collected to measure properties. According to the elemental analysis, molecular weight and 1 H-NMR data, average molecular structures of polycyclic aromatic and heavy resin were constructed with improved Brown-Ladner (B-L) method and several corrections. And then, the most stable conformations of polycyclic aromatic and heavy resin in vacuum and toluene solution were obtained by molecular dynamic simulation, and the molecular size was gotten via the radius of gyration analysis. The results showed that the radius of gyration of polycyclic aromatic and heavy resin was 0.55-0.70 nm in vacuum and 0.60-0.90 nm in toluene solution. With molecular weight increasing, the molecular size in vacuum and toluene solution also increased. Due to the swelling behavior of solvent, the alkyl side chains of heavy oil molecule in solution were more stretched. Thus, the molecular size in toluene solution was larger than that in vacuum.

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Molecular Size of Asphaltene Solubility Fractions

Cited by 139 publications

References 22 publications

Model molecules mimicking asphaltenes

Model molecules mimicking asphaltenes

Relation between Nanoscale Structure of Asphaltene Aggregates and their Macroscopic Solution Properties

Molecular size characterization of heavy oil fractions in vacuum and solution by molecular dynamic simulation

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