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Gonçalves, Maria Luísa A.; Teixeira, M. A. G.; Pereira, Roberto; Mercury, R. L. P.; Matos, J. R.

doi:10.1023/a:1011588226768

Cited by 62 publications

(15 citation statements)

References 7 publications

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“…62 However, for all cases, the pressure increase favors the amount of chemisorbed oxygen in the n-C 7 asphaltene structure due to the thermal expansion of the aggregates, increasing the number of active sites available for the interaction with oxygen atoms. 27 Although the oxygen content follows another order, a direct relationship with oxygen in the form of carboxyl groups in the molecular structure of the system was found. This demonstrates that the amount of chemisorbed oxygen depends not so much on the oxygen percentage present in the n-C 7 asphaltenes and aggregates but on whether it is found in a greater proportion as COO− groups.…”

Section: Resultsmentioning

confidence: 98%

“…The M W values obtained are in the range reported in other studies for asphaltenes isolated from HO and EHO. 27,45 4.1.2. FTIR Structural Characterization.…”

Section: Resultsmentioning

confidence: 99%

“…26 Finally, the asphaltene decomposition activation energy at HTO is reduced by the presence of saturates and resins because of the boosted coke formation. Goncalves et al 27 used n-C 7 asphaltenes with 85.8% carbon, 8.4% hydrogen, and 1.8% nitrogen, the mass-based composition, to investigate their thermal behavior through thermogravimetric experiments using different heating rates from 2 to 20 °C•min −1 under nitrogen and air atmospheres. The authors found in a first step an asphaltene mass loss of about 5% below 250 °C and a decrease in 45% between 250 and 550 °C, evidencing the coke formation, approximately equal to 50% of the initial mass.…”

Section: Introductionmentioning

confidence: 99%

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Thermo-Oxidative Decomposition Behaviors of Different Sources of n-C₇ Asphaltenes under High-Pressure Conditions

et al. 2020

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Effects of pressure on thermo-oxidative decomposition of different sources of n-C7 asphaltenes were investigated at high pressure using a thermogravimetric analyzer under an air atmosphere. The n-C7 asphaltenes were extracted from different heavy and extra-heavy crude oils around the world and were thoroughly characterized by elemental analysis (EA), vapor pressure osmometry (VPO), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and nuclear magnetic resonance (NMR) techniques. A high-pressure thermogravimetric analyzer coupled to a mass spectrometer was employed to obtain thermograms at 0.084, 3.0, and 6.0 MPa, and gaseous products were obtained by asphaltene decomposition. Kinetic analyses were performed for thermo-oxidative multistep reactions and compared based on the trends of pre-exponential factor and effective activation energies using an approximation of the Ozawa, Flynn, and Wall (OFW) isoconversional method. The n-C7 asphaltene decomposition profile was determined by four thermal events, namely, oxygen chemisorption (OC), desorption/decomposition of chemisorbed oxygen functional groups (DCO), and first and second combustion (FC and SC, respectively). We found that the amount of chemisorbed oxygen depends not so much on the oxygen percentage present in the n-C7 asphaltenes and aggregates but on whether it is found in a greater proportion as COO groups, independent of the used pressure. In addition, as the aromatization degree increases and the alkylation degree decreases, the amount of oxygen atoms chemisorbed also increases. As for the DCO region, it was corroborated that the increase in pressure from 0.084 to 6.0 MPa has a positive influence on the mass loss in this region for all samples used. The n-C7 asphaltenes with a higher chemisorption in the previous region showed a higher decomposition or loss of oxygenated compounds during DCO because there are more oxygenated groups in the basal plane of aromatic structures; therefore, the kinetics of the carbonaceous material consumption is increased. According to XPS analysis, n-C7 asphaltenes with a higher content of sulfur as thioethers show facilitated decomposition, due to the low energy required for their oxidation and subsequent cracking, throughout the range of evaluated pressures. Further, the higher content of hydrogen on α carbons to aromatic rings suggests that some of their small alkyl side chains are cracked in this zone due to the easy decomposition of α-methyl, α-methylene, and α-methine structures. As for the FC region, up to 3.0 MPa, a greater mass loss occurs in n-C7 asphaltenes with a high content of short aliphatic chains. Nevertheless, at 6.0 MPa, the mass loss percentage decreases in similar measures for all samples, indicating that under these conditions there is greater ease of breaking the functional groups located both in the basal plane of the aromatic rings and on the periphery of the molecule. Finally, during high-temperature oxidation reactions (SC), the higher a...

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Section: Resultsmentioning

confidence: 98%

“…The M W values obtained are in the range reported in other studies for asphaltenes isolated from HO and EHO. 27,45 4.1.2. FTIR Structural Characterization.…”

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Thermo-Oxidative Decomposition Behaviors of Different Sources of n-C₇ Asphaltenes under High-Pressure Conditions

et al. 2020

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“…In this stage, the aromatic molecules show a steady increment, asphaltenes decompose [20], and char is formed due to the condensation of free radical molecules. The char, which is found to be comparatively stable, is eventually burned.…”

Section: Resultsmentioning

confidence: 99%

An In-Depth Investigation into the Physicochemical, Thermal, Microstructural, and Rheological Properties of Petroleum and Natural Asphalts

Nciri

Kim

et al. 2016

Materials

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Over the last decade, unexpected and sudden pavement failures have occurred in several provinces in South Korea. Some of these failures remain unexplained, further illustrating the gaps in our knowledge about binder chemistry. To prevent premature pavement distress and enhance road performance, it is imperative to provide an adequate characterization of asphalt. For this purpose, the current research aims at inspecting the chemistry, microstructure, thermal, and physico-rheological properties of two types of asphalt, namely petroleum asphalt (PA) and natural asphalt (NA). The binders were extensively investigated by using elemental analysis, thin-layer chromatography with flame ionization detection (TLC-FID), matrix-assisted laser desorption ionization time-of-fight mass spectroscopy (MALDI-TOF-MS), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy (RS), Nuclear magnetic resonance spectroscopy (1H-NMR), ultraviolet and visible spectroscopy (UV-VIS), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), penetration, softening point, ductility, and viscosity tests. The findings of this research have revealed the distinct variations between the chemical compositions, microstructures, and thermo-rheological properties of the two asphalts and provided valuable knowledge into the characteristics of the binders. Such insight has been effective in predicting the performance or distress of road pavement. This paper will, therefore, be of immediate interest to materials engineers in state highway agencies and asphalt industries.

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“…%) was accompanied by the appearance of endothermic and exothermic effects and the elimination of water (H 2 O) and carbon dioxide (CO 2 ). The remaining residues of AMA and ACA above 650 • C were transformed into coke due to the formation of cyclic derivatives (pyrolysis: elimination of nitrogen N 2 , ethylene C 2 H 4 , and ethyl CH 3 -CH 2 -) [33]. We also noticed that the thermal stability of AIL (Figure 3e) and AIL-2 ( Figure 3f) showed new additional peaks at 450 • C, which also appeared in the QAE-Br thermogram (Figure 3d) to confirm the reaction of As-COCl or AMA with QAE-Br.…”

Section: Characterization Of Amphiphilic Asphaltene Ilsmentioning

confidence: 99%

Synthesis and Application of New Amphiphilic Asphaltene Ionic Liquid Polymers to Demulsify Arabic Heavy Petroleum Crude Oil Emulsions

et al. 2020

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Asphaltenes are heavy petroleum crude oil components which limit the production of petroleum crude oil due to their aggregation and their stabilization for all petroleum crude oil water emulsions. The present study aimed to modify the chemical structures of isolated asphaltenes by converting them into amphiphilic polymers containing ionic liquid moieties (PILs) to demulsify the emulsion and replace the asphaltene layers surrounding the oil or water droplets in petroleum crude oil emulsions. The literature survey indicated that no modification occurred to produce the PILs from the asphaltenes. In this respect, the asphaltenes were modified via oxidation of the lower aliphatic chain through carboxylation followed by conversion to asphaltene acid chloride that reacted with ethoxylated N-alkyl pyridinium derivatives. Moreover, the carboxylation of asphaltenes was carried out through the Diels–Alder reaction with maleic anhydride that was linked with ethoxylated N-alkyl pyridinium derivatives to produce amphiphilic asphaltene PILs. The produced PILs from asphaltenes acid chloride and maleic anhydride were designated as AIL and AIL-2. The chemical structure and thermal stability of the polymeric asphaltene ionic liquids were evaluated. The modified structure of asphaltenes AIL and AIL-2 exhibited different thermal characteristics involving glass transition temperatures (Tg) at −68 °C and −45 °C, respectively. The new asphaltenes ionic liquids were adsorbed at the asphaltenes surfaces to demulsify the heavy petroleum crude emulsions. The demulsification data indicated that the mixing of AIL and AIL-2 100 at different ratios with ethoxylated N-alkyl pyridinium were demulsified with 100% of the water from different compositions of O:W emulsions 50:50, 90:10, and 10:90. The demulsification times for the 50:50, 90:10, and 10:90 O:W emulsions were 120, 120, and 60 min, respectively. The interaction of the PILs with asphaltene and mechanism of demulsification was also investigated.

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Cited by 62 publications

References 7 publications

Thermo-Oxidative Decomposition Behaviors of Different Sources of n-C₇ Asphaltenes under High-Pressure Conditions

Thermo-Oxidative Decomposition Behaviors of Different Sources of n-C₇ Asphaltenes under High-Pressure Conditions

An In-Depth Investigation into the Physicochemical, Thermal, Microstructural, and Rheological Properties of Petroleum and Natural Asphalts

Synthesis and Application of New Amphiphilic Asphaltene Ionic Liquid Polymers to Demulsify Arabic Heavy Petroleum Crude Oil Emulsions

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Untitled

Cited by 62 publications

References 7 publications

Thermo-Oxidative Decomposition Behaviors of Different Sources of n-C7 Asphaltenes under High-Pressure Conditions

Thermo-Oxidative Decomposition Behaviors of Different Sources of n-C7 Asphaltenes under High-Pressure Conditions

An In-Depth Investigation into the Physicochemical, Thermal, Microstructural, and Rheological Properties of Petroleum and Natural Asphalts

Synthesis and Application of New Amphiphilic Asphaltene Ionic Liquid Polymers to Demulsify Arabic Heavy Petroleum Crude Oil Emulsions

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Product

Resources

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Thermo-Oxidative Decomposition Behaviors of Different Sources of n-C₇ Asphaltenes under High-Pressure Conditions

Thermo-Oxidative Decomposition Behaviors of Different Sources of n-C₇ Asphaltenes under High-Pressure Conditions