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

“…An important structural parameter, the aromaticity (f ar ) was determined using 13 C NMR. This parameter has been used widely in the literature (Fergoug and Bouhadda, 2014;Luo et al, 2010;Ostlund et al, 2004;Sanchez-Minero et al, 2013) to gauge the aromatic fraction. Figure 2 shows typical 13 C NMR spectra of Buton and its subfractions.…”

Section: Aromaticitymentioning

confidence: 99%

“…Snape and Ladner (1979) compiled a survey of 13 C chemical shift in aromatic hydrocarbons in coal-derived materials. Since then a large body of literature on asphaltene molecular parameters using 13 C NMR has been reported (Artok et al, 1999;Begon et al, 2003;Buenrostro-Gonzalez et al, 2001;Calemma et al, 1995;Christopher et al, 1996;Dickinson, 1980;Fergoug and Bouhadda, 2014;Gillet et al, 1980;Korb et al, 2013;Masuda et al, 1996;Michon et al, 1997;Myhr et al, 1990;Netzel, 1987;Ostlund et al, 2004;Rafenomanantsoa et al, 1994;Sanchez-Minero et al, 2013;Sheremata et al, 2004;Storm et al, 1994;Trejo et al, 2007;Yoshida et al, 1980). Likewise, since its introduction in 1988, laser desorption ionisation mass spectrometry has been increasingly used in the study of heavy fractions of petroleum (Karas and Hillenkamp, 1988).…”

Section: Introductionmentioning

confidence: 99%

Characterisation of subfractions of asphaltenes extracted from an oil sand using NMR, DEPT and MALDI-TOF

Zheng

Zhu

Zareie

et al. 2018

Journal of Petroleum Science and Engineering

View full text Add to dashboard Cite

This paper reports the findings of an investigation into molecular structures and properties of an oil sand asphaltene sample and its subfractions. The asphaltene sample extracted from Buton Oil Sand (Indonesia) was fractionated stepwise into four subfractions by precipitation in a binary solvent system made from mixtures of dichloromethane/n-heptane with volumetric ratios of 30/70, 20/80 and 10/90, respectively. The average molecular structural parameters, including the average polycyclic aromatic hydrocarbon size, average side chain length and average molecular weight of the oil sand asphaltene sample and its subfractions, were measured and compared, using characterisation data obtained from nuclear magnetic resonance in combination with distortionless enhancement by polarisation transfer. The molecular weight distributions of the asphaltene samples were measured using a matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry. The results indicated that the island molecular architecture was featured in all the asphaltene samples. The average polycyclic aromatic hydrocarbon size was found to be 7 rings for the least soluble subfraction, 6 rings for the other subfractions and the oil sand asphaltenes. The fractionation mechanism was dictated by polarity difference amongst subfractions as a result of relative luxuriance of the aliphatic parts. The use of 13 C NMR, DEPT and MALDI-TOF was shown to provide a useful means for characterisation and estimation of molecular structures of the asphaltenes.

show abstract

“…Estos, por lo general, se han usado para medir diferencias entre cambios en la concentración de asfaltenos en una misma disolución, por ejemplo, en estudios de adsorción de asfaltenos (7). Otros investigadores han propuesto un método que permite cuantificar el porcentaje de asfaltenos considerando una gran cantidad de crudos, basándose en medir la diferencia entre el crudo inicial diluido y los maltenos luego de precipitar los asfaltenos, a dos longitudes de onda distintas para corregir por línea de base y diferencias en los índices de refracción (8,9). La existencia de grupos aromáticos en la estructura de los asfaltenos, que son una familia más que una molécula particular, ayuda a su determinación por UV-Visible.…”

Section: Introductionunclassified

Estandarización del método espectroscópico UV-Visible para la determinación del contenido de asfaltenos en crudos pesados.

Samaniego

Rojas²,

Leone

et al. 2017

Ingeniería

View full text Add to dashboard Cite

Este estudio pretende implementar una metodología para lograr determinar el contenido de asfaltenos en crudos pesados resultantes de la aplicación del proceso de desasfaltación para disminuir el tiempo de medición y reducir el volumen del disolvente en comparación con el método convencional ASTM D 3279-07. Se logró mejorar la reproducibilidad de los datos en comparación con el método convencional. El tiempo de medición se redujo a menos de 3 horas en vez de 2 días, mientras que el volumen del disolvente se disminuyó a una cuarta parte.

show abstract

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

Cited by 74 publications

References 49 publications

NMR relaxometry and diffusometry in characterizing structural, interfacial and colloidal properties of heavy oils and oil sands

NMR relaxometry and diffusometry in characterizing structural, interfacial and colloidal properties of heavy oils and oil sands

Characterisation of subfractions of asphaltenes extracted from an oil sand using NMR, DEPT and MALDI-TOF

Estandarización del método espectroscópico UV-Visible para la determinación del contenido de asfaltenos en crudos pesados.

Contact Info

Product

Resources

About