Structural studies of asphaltics by x-ray small angle scattering

Pollack, S. S.; Yen, Teh Fu

doi:10.1021/ac60288a010

Cited by 67 publications

(41 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…On the other hand, the bond distance calculated between the centers of mass of asphaltene sheets was found to be around 4-5 Å, and the vertical distance to be 3.5 Å, which are in good agreement with X-ray diffraction and small angle scattering results reported by Yen et al [2,80] who reported the interlayer distance between two asphaltene sheets to be 3.55-3.70 Å. In addition, our result is comparable with those from Molecular Dynamics (MD) simulations that reported an interlayer distance of 3.5-4 Å [73,81].…”

Section: Diagonalsupporting

confidence: 89%

The influence of asphaltene-resin molecular interactions on the colloidal stability of crude oil

Mousavi

Abdollahi

Pahlavan

et al. 2016

Fuel

134

View full text Add to dashboard Cite

g r a p h i c a l a b s t r a c t Micellar structure of asphaltene in a dispersing medium of lighter resins, aromatics, and saturates. a b s t r a c tIn the colloidal hypothesis of vacuum residua and asphalt, micelles are assumed to have an asphaltenic core with the greatest weight and aromaticity and an outer shell composed of lighter and less aromatic molecules. The true nature of the micelles, and the asphaltenic core in particular, has always been a debatable issue among asphalt researchers. One of the frequently asked questions is whether asphaltenes exist as stacked layers within the micelles or as single molecular units stabilized by resin molecules. In this paper, we investigate the correlation between the number of asphaltene sheets and the final stability of the system in a medium of asphaltene and resin components. Our evaluation is based on rigorous quantum mechanical calculations using a DFT-D approach. Our quantitative findings corroborate the view that the colloidal behavior of crude oil is better described by asphaltene-asphaltene associations. Moreover, our calculations show that if both asphaltene and resin are present, resin-asphaltene interactions are preferred over asphaltene-asphaltene interactions only if the number of resin molecules per micelle is greater than the number of asphaltene molecules per micelle.

show abstract

Section: Diagonalsupporting

confidence: 89%

The influence of asphaltene-resin molecular interactions on the colloidal stability of crude oil

Mousavi

Abdollahi

Pahlavan

et al. 2016

Fuel

134

View full text Add to dashboard Cite

show abstract

“…Many different techniques, such as small angle neutron scattering (SANS) [44][45][46][47], small angle X-ray scattering (SAXS) [48][49][50][51], and fluorescence spectroscopy [52,53], have been employed for investigating the size of asphaltenes and various structures, such as disc-like and spherical, have been proposed to explain the data. For example, results from studies with SANS suggest that asphaltenes could have a disc-like geometry with radii between 30 and 100 Å [47], while SAXS studies have indicated that asphaltenes could be discs with a thickness of 3.4 Å and a radius between 12 and 800 Å [51].…”

Section: Correlation Of Average Diffusion Coefficients To Sizementioning

confidence: 99%

Characterization of fractionated asphaltenes by UV–vis and NMR self-diffusion spectroscopy

Östlund

Wattana

Nydén

et al. 2004

Journal of Colloid and Interface Science

View full text Add to dashboard Cite

“…The existence of ordered agglomerates has been proven by small angle X-ray scattering and small angle neutron scattering experiments [11][12][13] and the nature of asphaltene agglomeration is well established for different solvents, leading to problems and discussions regarding the size of the asphaltenes and their agglomerates [11,[14][15][16]. The existence of a bitumen microstructure and its visualization was performed by various techniques, ranging from confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) to atomic force microscopy (AFM) [17][18][19][20][21][22][23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Impact of maltene and asphaltene fraction on mechanical behavior and microstructure of bitumen

et al. 2015

View full text Add to dashboard Cite

As a widely accepted concept, bitumen consists of four fractions that can be distinguished by their polarity. Highly polar asphaltene micelles are dispersed in a viscous phase of saturates, aromatics and resins (maltene phase). Different concentrations of asphaltenes in the bitumen result in a range of mechanical response properties. In an interdisciplinary study the impact of the maltene phase and asphaltenes on the linear viscoelastic behavior and the microstructure of bitumen were analyzed by creep recovery testing in a DSR and by atomic force microscopy (AFM). Therefore, bitumen was separated into the maltene and asphaltene fractions and artificial bitumen samples with different, pre-defined asphaltene concentrations were produced and investigated. It was found that the artificially produced, precipitated bitumen samples can be regarded as a representative, bitumen-like material in terms of mechanical behavior and microstructure. Asphaltenes play an important role in the typical viscoelastic behavior of bitumen being mainly responsible for stiffness and elasticity. Also, their concentration appears to be correlated to the occurrence and shape of the bee-like inclusions which can be typically observed by AFM.

show abstract

Structural studies of asphaltics by x-ray small angle scattering

Cited by 67 publications

References 10 publications

The influence of asphaltene-resin molecular interactions on the colloidal stability of crude oil

The influence of asphaltene-resin molecular interactions on the colloidal stability of crude oil

Characterization of fractionated asphaltenes by UV–vis and NMR self-diffusion spectroscopy

Impact of maltene and asphaltene fraction on mechanical behavior and microstructure of bitumen

Contact Info

Product

Resources

About