Characterization of Thermally Degraded Asphaltene Fractions Using Gel Permeation Chromatography

Huang, J.

doi:10.1080/10916460500423536

Cited by 5 publications

(5 citation statements)

References 9 publications

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“…Both unfractionated asphaltenes reveal a considerable mass loss between 300 and 500 °C. Friesen et al already reported for Athabasca asphaltenes that all pyrolyzable material is decomposed below 525 °C, while Huang et al found that thermal decomposition occurred primarily between 350 and 450 °C for Florida asphaltenes …”

Section: Resultssupporting

confidence: 91%

“…Friesen et al already reported for Athabasca asphaltenes that all pyrolyzable material is decomposed below 525 °C, 68 while Huang et al found that thermal decomposition occurred primarily between 350 and 450 °C for Florida asphaltenes. 69 In contrast to the whole asphaltenes, the polarity fractions revealed a mass loss below 300 °C, indicating the release of enriched occluded material later discussed in detail. This result is consistent with the supramolecular assembly model for aggregation of asphaltenes introduced by Gray et al 66 The model implies the occlusion of maltene compounds by, e.g., acid−base interactions, hydrogen bonding, or metal coordina- tion, in addition to the well-known π−π stacking.…”

Section: ■ Results and Discussionmentioning

confidence: 90%

“…already reported for Athabasca asphaltenes that all pyrolyzable material is decomposed below 525 °C[67], whileHuang et al (2007) found that thermal decomposition occurred primarily between 350-450 °C for Florida asphaltenes[68].…”

mentioning

confidence: 86%

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Investigation of Island/Single-Core- and Archipelago/Multicore-Enriched Asphaltenes and Their Solubility Fractions by Thermal Analysis Coupled with High-Resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

et al. 2020

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Despite extensive research, the molecular-level chemical characterization of asphaltenes, a highly aromatic solubility fraction of petroleum, remains an analytical challenge. This fraction is related to diverse problems in crude oil exploration, transportation, and refining. Two asphaltene architecture motifs are commonly discussed in the literature, "island" (single-core)-and "archipelago" (multicore)-type structures. The thermal desorption and pyrolysis behavior of island-and archipelago-enriched asphaltenes and their extrography fractions was investigated. For this purpose, the evolved chemical pattern was investigated by thermal analysis coupled with ultrahigh-resolution mass spectrometry (Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS)). Soft atmospheric pressure chemical ionization preserved the molecular information of the thermal emission profile. Time-/temperature-resolved analysis allowed the chemical characterization of the occluded material as well as of asphaltene building blocks during pyrolysis. Regarding the thermogravimetric information, the island-type enriched sample (Wyoming asphaltenes) revealed a significantly higher coke residue after the pyrolysis process compared to the archipelago-type enriched sample (Athabasca asphaltenes). In contrast to whole asphaltenes, extrographic fractions revealed that occluded material evolved during the desorption phase. For the acetone fraction, this effect was the most abundant and suggests cooperative aggregation, which persists at high temperatures. Pyrolysis revealed a bimodal behavior for most of the compound classes, suggesting the presence of both architecture motifs in each asphaltene. double-bond equivalent (DBE) vs #C diagrams of the pyrolysis molecular profile revealed specific compositional trends: compounds with high DBE values and short alkylation are likely to be originated from island-type asphaltenes, whereas species with low DBE values and high carbon numbers likely derive from archipelago-type asphaltenes. In the asphaltene structural debate, thermal analysis ultrahigh-resolution mass spectrometry serves as an additional technique and supplements results obtained by other techniques, such as direct infusion approaches. Consistent results on the structural motifs are indicated by the molecular fingerprint visualized by DBE vs #C diagrams and serve as a measure for the dominance of a structural motif.

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Section: Resultssupporting

confidence: 91%

Section: ■ Results and Discussionmentioning

confidence: 90%

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Investigation of Island/Single-Core- and Archipelago/Multicore-Enriched Asphaltenes and Their Solubility Fractions by Thermal Analysis Coupled with High-Resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

et al. 2020

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“…For example, there has been debate in the research community about the best methods for estimating the number average molecular masses, often expressed as M n . The issues range from the choice of appropriate eluents in liquid chromatography − and solvents in vapor pressure osmometry (VPO) , to the choice of mass spectrometric techniques, as well as the selection of particular sample preparation and ionization methods within individual mass spectroscopic methods. ,,− …”

Section: Introductionmentioning

confidence: 99%

Characterization of Maya Crude Oil Maltenes and Asphaltenes in Terms of Structural Parameters Calculated from Nuclear Magnetic Resonance (NMR) Spectroscopy and Laser Desorption−Mass Spectroscopy (LD−MS)

et al. 2010

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Fractions of Maya (Mexico) crude oil were examined by quantitative liquid-state 1 H and 13 C nuclear magnetic resonance (NMR) spectroscopy. The NMR data was combined with molecular-mass estimates determined in a previous work to calculate average structural parameters. The approach clearly showed structural differences between the fractions and allowed for the inference of detailed information on the chemical structures involved. The sample of crude oil was first fractionated into maltenes and asphaltenes, and the asphaltenes were further sub-fractioned into 1-methyl-2-pyrrolidinone (NMP)-soluble (labeled as "MNS") and NMP-insoluble (labeled as "MNI") fractions. The aromatic rings per average molecule value derived were 2-5 for the MM sample, 8-10 for the MA sample, ∼5 for the MNS sample, and 11-38 for the MNI sample. Thus, while some differences between maltenes and asphaltenes could be expected from prior general knowledge, some results were unexpected. The MNS fraction turned out to be more aliphatic than the MNI fraction. On average, the MNS sample appeared to contain a greater number of smaller aromatic cores, linked by means of biphenyl-like aromatic-aromatic single bonds and aliphatic/naphthenic bridges, and shorter aliphatic side chains. If the aromatic groups are in external positions, this would account for the solubility of these species in NMP (a more open structure). Meanwhile, results for the MNI sample strongly suggest fewer, larger aromatic cores per average molecule, linked by long alkyl side chains and naphthenic structures. The alkyl substituents would appear to form a barrier between the aromatic core and the solvent. These findings have implications regarding how different structural sub-groups within an asphaltene will respond to ultraviolet (UV) laser desorption-mass spectrometry (LD-MS) and UV-fluorescence spectroscopy.

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“…(2005) already reported for Athabasca asphaltenes that all pyrolyzable material is decomposed below 525 °C [67], while Huang et al (2007) found that thermal decomposition occurred primarily between 350-450 °C for Florida asphaltenes [68]. In contrast to the whole asphaltenes, the polarity fractions revealed a mass loss below 300 °C indicating the release of enriched occluded material later discussed in detail.…”

Section: Resultsmentioning

confidence: 82%

Investigation of Island/ Single Core and Archipelago/ Multicore Enriched Asphaltenes and Their Solubility Fractions by Thermal Analysis Coupled to High Resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Neumann¹,

Chacón-Patiño²,

Rodgers³

et al. 2020

Preprint

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Despite extensive research, the molecular-level chemical characterization of asphaltenes, a highly aromatic solubility fraction of petroleum, remains an analytical challenge. This fraction is related to diverse problems in crude oil exploration, transportation, and refining. Two asphaltene architecture motifs are commonly discussed in literature, “island” (single core) and “archipelago” (multicore) type structures. The thermal desorption and pyrolysis behavior of island- and archipelago-enriched as-phaltenes and their extrography fractions was investigated. For this purpose, the evolved chemical pattern was investigated by thermal analysis coupled to ultrahigh resolution mass spectrometry (FT-ICR MS). Soft atmospheric pressure chemical ionization preserved the molecular information of the thermal emission profile. Time/temperature-resolved analysis allowed the chemical characterization of occluded material as well as of asphaltene building blocks during pyrolysis.Regarding the thermogravimetric information, the island-type enriched sample (Wyoming asphal-tenes) revealed a significantly higher coke residue after the pyrolysis process compared to the archi-pelago-type enriched sample (Athabasca asphaltenes). In contrast to whole asphaltenes, extrograph-ic fractions revealed occluded material evolved during the desorption phase. For the acetone frac-tion, this effect was most abundant and suggests cooperative aggregation.Pyrolysis revealed a bimodal behavior for most of the compound classes suggesting the presence of both architecture motifs in each asphaltene. DBE versus #C diagrams of the pyrolysis molecular pro-file revealed specific compositional trends: compounds with high DBE values and short alkylation likely to be originated from island-type asphaltenes, whereas species with low DBE values and high carbon numbers likely derive from archipelago-type asphaltenes.In the asphaltene structural debate, thermal analysis ultrahigh resolution mass spectrometry serves as additional technique and supplements results obtainable by other techniques, such as direct infu-sion approaches. Consistent results on the structural motifs are indicated by the molecular finger-print visualized by DBE versus #C diagrams and serve as measure for the dominance of a structural motif.

show abstract

Characterization of Thermally Degraded Asphaltene Fractions Using Gel Permeation Chromatography

Cited by 5 publications

References 9 publications

Investigation of Island/Single-Core- and Archipelago/Multicore-Enriched Asphaltenes and Their Solubility Fractions by Thermal Analysis Coupled with High-Resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Investigation of Island/Single-Core- and Archipelago/Multicore-Enriched Asphaltenes and Their Solubility Fractions by Thermal Analysis Coupled with High-Resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Characterization of Maya Crude Oil Maltenes and Asphaltenes in Terms of Structural Parameters Calculated from Nuclear Magnetic Resonance (NMR) Spectroscopy and Laser Desorption−Mass Spectroscopy (LD−MS)

Investigation of Island/ Single Core and Archipelago/ Multicore Enriched Asphaltenes and Their Solubility Fractions by Thermal Analysis Coupled to High Resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

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