Table 1.
Elemental analyses of resin and asphaltene fractions before and after derivatization with hydroxylamine and aniline.
Fig 1.
Quantitative liquid-state C-13 NMR spectra of asphaltene before and after PTC-methylation with 13CH3I.
LB = line broadening. For the underivatized asphaltene, carbon aromaticity(fa) = 0.63.
Fig 2.
Quantitative liquid-state C-13 NMR spectra of resin before and after PTC-methylation with 13CH3I.
LB = line broadening. For the underivatized resin, carbon aromaticity(fa) = 0.33.
Fig 3.
Liquid-state DEPTGL C-13 NMR methyl subspectra of asphaltene before and after PTC-methylation with 13CH3I.
LB = line broadening.
Fig 4.
Liquid-state DEPTGL C-13 NMR spectra showing all protonated carbons of asphaltene before and after 13C-diazomethylation.
LB = line broadening.
Fig 5.
Liquid-state DEPTGL C-13 NMR methyl subspectra of resin before and after PTC-methylation with 13CH3I and 13C-diazomethylation.
LB = line broadening.
Fig 6.
Carbon-13 NMR chemical shift ranges and examples of O-CH3, N-CH3, C-CH3 and S-CH3 methyl carbons resulting from methylation of acidic oxygen, carbon, nitrogen and sulfur groups.
Fig 7.
Solid-state CP/MAS N-15 NMR spectrum of naturally abundant asphaltene nitrogen.
LB = line broadening. ct = contact time. Spinning speed = 5 kHz.
Fig 8.
Solid-state CP/MAS N-15 NMR spectra of asphaltene and resin derivatized with 15N-labeled hydroxylamine.
LB = line broadening. ct = contact time. Spinning speed = 5 kHz for resin and 6 kHz for asphaltene. Asterisks denote spinning sidebands.
Fig 9.
Reactions of carbonyl groups with hydroxylamine.
Fig 10.
Nitrogen-15 NMR chemical shifts in ppm for oximes and Beckmann reaction products.
From reference {Thorn, 1992 #523}. Separate resonances are observed for the Z and E isomers of ketoximes. In general, the E isomers of ketoximes are deshielded with respect to the Z isomers.
Table 2.
Assignments for N-15 NMR spectra of resin and asphaltene fractions derivatized with hydroxylamine.
Fig 11.
Solid-state CP/MAS N-15 NMR spectrum of asphaltene derivatized with 15N-labeled aniline.
LB = line broadening. ct = contact time. Spinning speed = 6 kHz.
Fig 12.
Reactions of carbonyl groups with aniline.
Fig 13.
Nitrogen-15 NMR chemical shifts in ppm for Schiff Bases and condensation products of aniline with carbonyl compounds.
From reference {Thorn, 1996 #277}. (a) Determined in CDCl3, referenced to neat aniline as 55.7 ppm. (b) Determined in CD3OD, referenced to neat formamide as 112.4 ppm. (b) Determined in DMSO-d6, referenced to neat formamide as 112.4 ppm.
Table 3.
Assignments for N-15 NMR spectra of asphaltene derivatized with aniline.
Fig 14.
Liquid-state DEPT N-15 NMR spectra of asphaltene and resin derivatized with 15N-labeled aniline.
LB = line broadening.