Spectroscopic identification of basic nitrogen compounds in Wilmington petroleum

Brandenburg, C.F.; Latham, D. R.

doi:10.1021/je60038a027

Cited by 37 publications

(18 citation statements)

References 8 publications

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“…1,2,[10][11][12] Under combustion conditions these heterocycles may form nitrogen precursors of NOx, and the rate of precursor formation may determine the rate of NOx formation. Thus, it is important to understand the reaction mechanism and kinetics of these heterocycles at combustion temperatures.…”

Section: Introductionmentioning

confidence: 99%

A Theoretical Study of Pyrolysis Mechanisms of Pyrrole

1999

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Density functional theory and ab initio calculations were carried out to investigate the pyrolysis mechanisms of pyrrole. All equilibrium and transition state structures of the proposed reaction channels were fully optimized by the density functional B3LYP method using the 6-31G(d,p) basis set. Relative energies were evaluated at the QCISD(T)/6-311G(d,p) level of theory. In addition to the mechanism proposed in experimental studies, alternative unimolecular pathways for the formation of cis-crotonitrile and allyl cyanide, major nitrogencontaining isomerization products, were proposed and investigated. The results suggest that a mechanism proposed in the present study is more likely responsible for the formation of allyl cyanide. For the formation of cis-crotonitrile, a mechanism proposed in the present study should also be competitive, especially under low-pressure conditions. Although extensive calculations were carried out, we failed to identify a unimolecular decomposition pathway generating HCN, another major nitrogen-containing pyrolysis product, with an activation barrier close to the experimental value.

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Section: Introductionmentioning

confidence: 99%

A Theoretical Study of Pyrolysis Mechanisms of Pyrrole

1999

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“…Afterward, the reaction mechanism was discussed, and using vibrational mode analysis, frontier orbital analysis and electron population analysis to reveal the reaction mechanism was firstly reported. The results show that, for 1-penten-4-yl (b), the energetically most favourable channel is a→TSb4→IMb1→TSb5→IMb2→TSb6→ butadiene＋CH 3 , and the products of this channel are the same as those of 1-penten-3-yl (a). The main products of 1-penten-5-yl (c) may be C 2 H 4 and C 3 H 5 radical because the potential energy of TSc3 is very high, but intermediate cyclopentyl is of low internal energy.…”

Section: Resultsmentioning

confidence: 95%

“…When used as energy sources, they can produce free radicals and precursors of polycyclic aromatic hydrocarbons. These radicals may give rise to negative effects on our circumstances, and some in the form of aromatic heterocycles 2 like pyridyl radicals 3,4 even pollute atmosphere. Successive pyrolytic degradation of large radical structures can lead to smaller unsaturated fragments via isomerization and bond cleavage.…”

Section: Introductionmentioning

confidence: 99%

Reaction Mechanism of the Multi‐channel Decomposition Reactions of 1‐Pentenyl Free Radicals

Cheng¹,

Zhao²,

Li³

et al. 2008

Chin. J. Chem.

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The reactions of 1-pentenyl decomposition system have been studied extensively at the B3LYP/6-311＋＋G** level with Gaussion 98 package. The potential energy surface with zero-point energy correction was drawn. All reaction channels were fully investigated with the vibrational mode analysis, frontier orbital analysis and electron population analysis to confirm the transition states and reveal the reaction mechanism.

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“…This spectrum is similar to that of many substituted pyridines and pyridine benzolog model compounds which show two absorption bands near 1600 cm-I with the higher wavenumber band having the stronger absorption intensity. Spectra of pyridine compounds showing two absorption bands have been previously observed in a Wilmington petroleum sample (14). Fluorescence spectra were obtained for several subfraction 1 samples that were further separated using gelpermeation chromatography and thin-layer chromatography.…”

Section: Correlation Of Titration and Total Nitrogen Datamentioning

confidence: 81%

Characterization of nitrogen bases in high-boiling petroleum distillates

McKay¹,

Weber²,

Latham³

1976

Anal. Chem.

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138

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The nitrogen bases in eight high-bolllng crude oil distillates from four crude oils having different geological sources were characterized. Four basic compound types were found in all of the distillates-pyridine benzologs, dlaza compounds, amides, and carbazoles. A chromatographlcinfrared method was developed for the qualitative and quantitative determination of the major compound types. t h e data obtained using this method were compared with titration and total nitrogen data. This comparison demonstrated that the chromatographic-infrared method alone can be used to qualitatively and quantitatively analyze basic compound types in high-boiling petroleum distillates and that titration and total nitrogen data alone can be used to quickly estimate the kinds and amounts of major compound types in these distillates. The structures of the basic compounds were examined in detail using fluorescence, mass, and infrared spectrometry.Crude oil distillates may be separated into seven fractions-acids, bases, neutral nitrogens, saturates, monoaromatics, diaromatics, and polyaromatics-using the separation scheme developed by the Bureau of Mines in American Petroleum Institute Research Project 60 (1, 2 ) . Further characterization of these fractions is desirable to identify the major compound types. The polar compound types are important constituents of petroleum because, even in small amounts, they cause serious problems in processing and in the stability of the products. For example, the polar compounds cause catalyst poisoning and are involved with the formation of gums in products. Characterization of the acid fractions has been reported ( 3 ) . The analysis of base fractions according to compound types is discussed in this paper.Early work on petroleum bases has been reviewed by Lochte and Littman ( 4 ) . Much credit is due to the early workers who, without modern spectroscopic instrumentation, have identified many individual pyridine, quinoline, and benzoquinoline compounds. Recent research by Snyder (5-7) and Jewel1 and Hartung (8) has extended the compositional studies to include the identification of amides, compounds containing both nitrogen and sulfur, and diaza compounds. Quantitative estimates of the different compound types have also been made using mass spectrometry (5-7) and potentiometric titration (9-21).This investigation extends previous work by developing a standardized scheme of analyzing basic compound types in 370-535 "C and 535-675 "C petroleum distillates. Bases in crude oils from four different geological sources were studied to compare the composition of the base fractions.First described are titration data and elemental nitrogen and sulfur analyses of total base fractions. Second, a method is described involving adsorption chromatography and infrared spectrometry that was developed for the qualitative and quantitative determination of major compound types. T h e results obtained using this chromatographicinfrared method are then compared with the results of the Petroleum titration and total nitrogen ...

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Spectroscopic identification of basic nitrogen compounds in Wilmington petroleum

Cited by 37 publications

References 8 publications

A Theoretical Study of Pyrolysis Mechanisms of Pyrrole

A Theoretical Study of Pyrolysis Mechanisms of Pyrrole

Reaction Mechanism of the Multi‐channel Decomposition Reactions of 1‐Pentenyl Free Radicals

Characterization of nitrogen bases in high-boiling petroleum distillates

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