<sup>13</sup>C NMR STUDIES ON ROADWAY ASPHALTS

Hagen, A. P.; Johnson, Marie Ponder; Randolph, B. B.

doi:10.1080/08843758908962291

Cited by 13 publications

(16 citation statements)

References 33 publications

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“…spectrum of AOSA containing carbon-13 only at the natural isotopic abundance of 1.1% (Figs 1 and 5). Therefore, although ketones and sulfoxides are known oxidation products of asphaltic substances [28,30,31], they are not readily detected in the 13 C n.m.r. spectrum of AOSA when present in small quantities.…”

Section: Carbon-13 and Fluorine-19 Nmr Spectroscopymentioning

confidence: 99%

The low temperature oxidation of Athabasca oil sand asphaltene observed from 13C, 19F, and pulsed field gradient spin-echo proton n.m.r. spectra

Desando

Lahajnar

Ripmeester

et al. 1999

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The low temperature oxidation of Athabasca oil sand asphaltene observed from 13C, 19F and pulsed field gradient spin-echo proton n.m.r. spectra Desando, Michael A.; Lahajnar, Gojmir; Ripmeester, John A.; Zupancic, Ivan AbstractCarbon-13 and fluorine-19 nuclear magnetic resonance spectra of chemically derivatized, by phase transfer methylation and trifluoroacetylation, Athabasca oil sand asphaltene, reveal a broad site distribution of different types of hydroxyl-containing functional groups, viz., carboxylic acids, phenols, and alcohols. The low temperature air oxidation of asphaltene, at ca. 130ЊC for 3 days, generates a few additional carboxyl and phenolic groups. These results are consistent with a mechanism in which diaryl methylene and ether moieties react with oxygen. Self-diffusion coefficients, from the pulsed field gradient spin-echo proton magnetic resonance technique, suggest that low temperature oxidation does not appreciably alter the average particle size and diffusion properties of asphaltene in deuterochloroform. ᭧

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Section: Carbon-13 and Fluorine-19 Nmr Spectroscopymentioning

confidence: 99%

The low temperature oxidation of Athabasca oil sand asphaltene observed from 13C, 19F, and pulsed field gradient spin-echo proton n.m.r. spectra

Desando

Lahajnar

Ripmeester

et al. 1999

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“…It consists of two fractions, heavy oils and resins [2-6, [12][13][14][15][16][17][18]. These oils are the liquid part of the asphalt and consist of normal-, iso-and cyclo-paraffins and condensed naphthenes with some alkyl aromatics.…”

Section: Heavy Oilsmentioning

confidence: 99%

Certain Relationships between Chemical Composition and Properties of Petroleum Asphalts from Different Origin

Oyekunle¹

2006

Oil & Gas Science and Technology - Rev. IFP

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Résumé -Des relations entre la composition chimique et les propriétés de bitumes d'origines différentes -Les bitumes sont habituellement classés selon trois propriétés physiques : ductilité, pénétration et point de ramollissement. L'étude présentée ici démontre à travers plusieurs exemples que ces traits physiques ne sont pas assez distinctifs. Il a été découvert que la composition chimique apporte davantage d'enseignements sur les différentes propriétés physiques des bitumes. On note des différences remarquables entre la composition chimique de bitumes de même point de ramollissement et de même origine. Une plus grande ductilité provient d'une plus forte teneur en résines alors qu'une pénétration moindre est la conséquence d'une plus grande teneur en asphaltènes. La corrélation de deux indices et de la composition de bitumes révèle que l'indice Gaestël (1 c ) est un meilleur paramètre de caractérisation de bitumes que l'indice d'asphaltène (1 A ). Ces deux indices peuvent être utilisés comparativement pour distinguer des bitumes ayant des points de ramollissement voisins. Abstract -Certain Relationships between Chemical Composition and Properties of Petroleum

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“…However, the isotopically enhanced carbon-13 NMR spectra are sensitive to slight changes at the molecular level, and reveal at least three different Fig. 6 [41,55]. The experiment also reveals that the broad unresolved band of overlapping resonances at ca.…”

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confidence: 90%

Chemical derivatization of Athabasca oil sand asphaltene for analysis of hydroxyl and carboxyl groups via nuclear magnetic resonance spectroscopy

Desando

2002

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Athabasca oil sand asphaltene was methylated with different base catalyst/solvent combinations in order to ®nd an optimum procedure for analysis of the number and types of hydroxyl and carboxyl functional groups. High resolution carbon-13,¯uorine-19, and silicon-29 NMR spectra were used to monitor the degree of methylation, tri¯uoroacetylation, trimethylsilylation, and aromaticity of asphaltene. Tetra-nbutylammonium hydroxide as phase transfer base catalyst and tetrahydrofuran or dichloromethane as solvent result in enhanced O-methylation of asphaltene. At least two types of acidic oxygen containing functionality have been detected, viz. hydroxyl and carboxyl (aliphatic and aryl). On average there are few, #4±8, hydroxyl containing groups (including COOH) per asphaltene molecule.13 C NMR lineshapes suggest a broad asymmetric distribution of acidic sites. The NMR and elemental analyses allow for oxygen containing functionalities to be included in an average molecular structure. A sludge phase collected from aqueous and hydrochloric acid extractions of asphaltene has also been analyzed. A correlation is observed between the degree of O-methylation and the dielectric permittivity of the solvent and the acidity of the substrate reaction site. q

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¹³C NMR STUDIES ON ROADWAY ASPHALTS

Cited by 13 publications

References 33 publications

The low temperature oxidation of Athabasca oil sand asphaltene observed from 13C, 19F, and pulsed field gradient spin-echo proton n.m.r. spectra

The low temperature oxidation of Athabasca oil sand asphaltene observed from 13C, 19F, and pulsed field gradient spin-echo proton n.m.r. spectra

Certain Relationships between Chemical Composition and Properties of Petroleum Asphalts from Different Origin

Chemical derivatization of Athabasca oil sand asphaltene for analysis of hydroxyl and carboxyl groups via nuclear magnetic resonance spectroscopy

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13C NMR STUDIES ON ROADWAY ASPHALTS

Cited by 13 publications

References 33 publications

The low temperature oxidation of Athabasca oil sand asphaltene observed from 13C, 19F, and pulsed field gradient spin-echo proton n.m.r. spectra

The low temperature oxidation of Athabasca oil sand asphaltene observed from 13C, 19F, and pulsed field gradient spin-echo proton n.m.r. spectra

Certain Relationships between Chemical Composition and Properties of Petroleum Asphalts from Different Origin

Chemical derivatization of Athabasca oil sand asphaltene for analysis of hydroxyl and carboxyl groups via nuclear magnetic resonance spectroscopy

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¹³C NMR STUDIES ON ROADWAY ASPHALTS