A two-step chemistry for highlighting heteroatom species in petroleum materials using carbon-13 NMR spectroscopy

Rose, Kenneth D.; Francisco, Manuel

doi:10.1021/ja00210a075

Cited by 37 publications

(30 citation statements)

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“…51 and 55 ppm, respectively. Primary alkanols, except methanol (Ϫ7.71 ppm), have 19 F chemical shifts upfield from Ϫ7.88 ppm, and from the low signal in this region are present in small amounts in the unoxidized material, as substantiated from 13 C n.m.r. spectra.…”

Section: Carbon-13 and Fluorine-19 Nmr Spectroscopymentioning

confidence: 94%

“…peaks in the narrow range, ca. 58-59 ppm [11][12][13], which may be hidden, but contribute resonance signal in the region of overlap of the two much larger methyl aryl ether bands.…”

Section: Carbon-13 and Fluorine-19 Nmr Spectroscopymentioning

confidence: 99%

“…52-53 ppm (Figs 2 and 3). In the correlation of molecular structures to the 13 [5,14,15]. Experimental evidence in favour of the methyl ester nature of the 50-53 ppm resonance comes from:…”

Section: Carbon-13 and Fluorine-19 Nmr Spectroscopymentioning

confidence: 99%

“…The fact that this phenomenon occurs for PTM reaction in THF or dichloromethane, of asphaltene or oxidized asphaltene, suggests that it is caused by reaction with methyl iodide and the base tetra-n-butylammonium hydroxide, and not from the sharp minor resonances of unreacted reagents. For example, in deuterochloroform, tetra-n-butylammonium hydroxide has 13 C n.m.r. peaks at ca.…”

Section: Carbon-13 and Fluorine-19 Nmr Spectroscopymentioning

confidence: 99%

“…Ϫ23 ppm. Candidates for the increased signals are S-CH 3 (10-23 ppm), C-CH 3 (18-31 ppm), and N-CH 3 (30-50 ppm) methylation products [12,13,19]. Spectral editing techniques, viz.…”

Section: Carbon-13 and Fluorine-19 Nmr Spectroscopymentioning

confidence: 99%

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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

Lahajnar

Ripmeester

et al. 1999

Fuel

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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: 94%

“…peaks in the narrow range, ca. 58-59 ppm [11][12][13], which may be hidden, but contribute resonance signal in the region of overlap of the two much larger methyl aryl ether bands.…”

Section: Carbon-13 and Fluorine-19 Nmr Spectroscopymentioning

confidence: 99%

“…52-53 ppm (Figs 2 and 3). In the correlation of molecular structures to the 13 [5,14,15]. Experimental evidence in favour of the methyl ester nature of the 50-53 ppm resonance comes from:…”

Section: Carbon-13 and Fluorine-19 Nmr Spectroscopymentioning

confidence: 99%

Section: Carbon-13 and Fluorine-19 Nmr Spectroscopymentioning

confidence: 99%

“…Ϫ23 ppm. Candidates for the increased signals are S-CH 3 (10-23 ppm), C-CH 3 (18-31 ppm), and N-CH 3 (30-50 ppm) methylation products [12,13,19]. Spectral editing techniques, viz.…”

Section: Carbon-13 and Fluorine-19 Nmr Spectroscopymentioning

confidence: 99%

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