Fullerenes and PAH in low-pressure premixed benzene/oxygen flames

Grieco, William J.; Lafleur, Arthur L.; Swallow, Kathleen C.; Richter, Hanz; Taghizadeh, Koli; Howard, Jack B.

doi:10.1016/s0082-0784(98)80006-4

Cited by 54 publications

(42 citation statements)

References 14 publications

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“…2e. Shorter flames, which result from higher dilution or lower pressure, favor fullerenes over soot, possibly indicating fullerene consumption by soot, as has also been suggested based on behavior seen in premixed flames [17]. This consumption should be slower for lower pressures and higher dilutions because of lower soot concentrations.…”

Section: Fullerenesmentioning

confidence: 64%

Synthesis of fullerenes and fullerenic nanostructures in a low-pressure benzene/oxygen diffusion flame

Hebgen

Goel

Howard

et al. 2000

Proceedings of the Combustion Institute

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Samples of condensable material from laminar low-pressure benzene/argon/oxygen diffusion flames were collected and analyzed by high-performance liquid chromatography to determine the yields of fullerenes and by high-resolution transmission electron microscopy (HRTEM) to characterize the fullerenic material (i.e., curved-layer nanostructures) on and within the soot particles. The highest concentration of fullerenes was always detected just above the visible stoichiometric surface of a flame. The percentage of fullerenes in the condensable material increases with decreasing pressure. The overall highest amount of fullerenes was found for a surprisingly high dilution of fuel with argon. A comparison of the flames with the same cold gas velocity of fuel and oxygen showed a strong dependence of fullerene content on flame length. A shorter flame, resulting from higher dilution or lower pressure, favors the formation of fullerenes rather than soot, and the amount of soot and precursors of both soot and fullerenes is less at lower pressure and higher dilution. This behavior indicates a stronger correlation of fullerene consumption to the total amount of soot than of fullerene formation to precursor concentration. The maximum flame temperature seems to be of minor importance in fullerene formation. The HRTEM analysis of the soot showed an increase of the curvature of the carbon layers, and hence increased fullerenic character, with increasing distance from the burner up to the point of maximum fullerene concentration. After this maximum, where soot and fullerenes are consumed by oxidation, the curvature decreases. In addition to the soot, the samples included fullerenic nanostructures such as tubes and spheroids including highly ordered multilayered or onionlike structures. The soot itself shows highly ordered regions that appear to have been cells of ongoing fullerenic nanostructure formation.

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Section: Fullerenesmentioning

confidence: 64%

Synthesis of fullerenes and fullerenic nanostructures in a low-pressure benzene/oxygen diffusion flame

Hebgen

Goel

Howard

et al. 2000

Proceedings of the Combustion Institute

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“…Grieco et al found [28] that in the flame reaction zone, the quantity of closed-shell structures in soot, as well as the fullerene concentration in the gas phase, increases with increasing residence time. At a distance of more than 70 mm above the burner, the fullerene concentration decreased, and at a distance between 60 and 120 mm the concentration of closed-shell structures decreased.…”

Section: Fullerenes and Their Formation During Combustionmentioning

confidence: 99%

“…The concentrations profiles of fullerenes [28] are characterized (Fig. 8) by two local maxima, the first of which is smaller.…”

Section: Fullerenes and Their Formation During Combustionmentioning

confidence: 99%

“…8) by two local maxima, the first of which is smaller. Studying the evolution of the concentrations of fullerenes, PAHs, and soot with increasing distance above the burner, Grieco et al [28] draw the conclusion that the first maximum may be due to the reactive coagulation of PAHs, accompanied by intramolecular condensation, including dehydrogenation, rearrangement, and ring formation. Apparently, PAHs are mostly consumed in soot formation, and to a lesser extent in fullerene formation.…”

Section: Fullerenes and Their Formation During Combustionmentioning

confidence: 99%

“…Apparently, PAHs are mostly consumed in soot formation, and to a lesser extent in fullerene formation. Grieco et al [28] concluded that the second concentration maximum, which is in the region of the most intense fullerene formation, cannot be attributed to reactions involving PAHs alone, whose concentrations in this region are at or below the detection limit of analytical equipment, but it can be explained by sequential attachment of acetylene to PAHs.…”

Section: Fullerenes and Their Formation During Combustionmentioning

confidence: 99%

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Supramolecular Ensembles Formed via Calix[5]arene‐Fullerene Host‐Guest Interactions

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This Review introduces the research directions for the synthesis of supramolecular fullerene polymers. First, the discovery of host-guest complexes of pristine fullerenes is briefly outlined. We focus on progress in supramolecular fullerene polymers directed by the use of calix[5]arenefullerene interactions, which comprise linear, networked, helical arrays of fullerenes in supramolecular ensembles. The unique self-sorting behavior of right-handed and left-handed helical supramolecular fullerene arrays is discussed. Thereafter, an extensive investigation of the calix[5]arene-fullerene interaction for control over the chain structures of covalent polymers is introduced.

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Fullerenes and PAH in low-pressure premixed benzene/oxygen flames

Cited by 54 publications

References 14 publications

Synthesis of fullerenes and fullerenic nanostructures in a low-pressure benzene/oxygen diffusion flame

Synthesis of fullerenes and fullerenic nanostructures in a low-pressure benzene/oxygen diffusion flame

Soot Formation in Combustion Processes (Review)

Supramolecular Ensembles Formed via Calix[5]arene‐Fullerene Host‐Guest Interactions

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