Proposed fullerene precursor corannulene identified in flames both in the presence and absence of fullerene production

Lafleur, Arthur L.; Howard, Jack B.; Marr, Joseph A.; Yadav, Tapesh

doi:10.1021/j100153a020

Cited by 76 publications

(59 citation statements)

References 9 publications

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“…It is similar to the spectrum of corannulene in ethanol reported by Barth and Lawton. [13] It is also similar to the spectrum of the corannulene reference standard in solution reported by Lafleur et al [17] The inset displays also Figure 4. Raman spectrum of a crystal grain of corannulene at room temperature.…”

supporting

confidence: 84%

IR, Raman, and UV/Vis Spectra of Corannulene for Use in Possible Interstellar Identification

Rouillé¹,

Jäger²,

Steglich³

et al. 2008

ChemPhysChem

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The spectroscopic characterization of corannulene (C(20)H(10)) is carried out by several techniques. The high purity of the material synthesized for this study was confirmed by gas chromatography-mass spectrometry (GC-MS). During a high-performance liquid chromatography (HPLC) process, the absorption spectrum of corannulene in the ultraviolet (UV) and visible (vis) ranges is obtained. The infrared (IR) absorption spectrum is measured in CsI pellets, and the Raman scattering spectrum is recorded for pure crystal grains. In addition to room temperature measurements, absorption spectroscopy in an argon matrix at 12 K is also performed in the IR and UV/Vis ranges. The experimental spectra are compared with theoretical Raman and IR spectra and with calculated electronic transitions. All calculations are based on the density functional theory (DFT), either normal or time-dependent (TDDFT). Our results are discussed in view of their possible application in the search for corannulene in the interstellar medium.

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supporting

confidence: 84%

IR, Raman, and UV/Vis Spectra of Corannulene for Use in Possible Interstellar Identification

Rouillé¹,

Jäger²,

Steglich³

et al. 2008

ChemPhysChem

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“…The elimination of CO from oxidized PAH is thought to be a source of fivemembered rings [115] in the structure of combustion-generated PAH, which are precursors to fullerenes in flames [32,92,116]. However, the highest concentration of fullerenes is in the region of the flame where the precursor concentration is decreasing due to oxidation.…”

Section: Fullerenesmentioning

confidence: 99%

Combustion synthesis of fullerenes and fullerenic nanostructures

Goel

Hebgen

Sande

et al. 2002

Carbon

117

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Fullerenes are molecules comprised entirely of sp 2 -bonded carbon atoms arranged in pentagonal and hexagonal rings to form a hollow, closed-cage structure. Buckyballs, a subset which contains C 60 and C 70 , are single-shell molecules while fullerenic nanostructures can contain many shells and over 300 carbon atoms. Both fullerenes and nanostructures have an array of applications in a wide variety of fields, including medical and consumer products. Fullerenes were discovered in 1985 and were first isolated from the products of a laminar low-pressure premixed benzene/oxygen/argon flame operating at fuel-rich conditions in 1991. Flame studies indicated that fullerene yields depend on operating parameters such as temperature, pressure, residence time, and equivalence ratio. High-resolution transmission electron microscopy (HRTEM) showed that the soot contains nanostructures, including onions and nanotubes.Although flame conditions for forming fullerenes have been identified, the process has not been optimized and many flame environments of potential interest are unstudied. Mechanistic characteristics of fullerene formation remain poorly understood and cost estimation of large-scale production has not been performed. Accordingly, this work focused on: 1) studying fullerene formation in diffusion and premixed flames under new conditions to identify optimal parameters; 2) investigating the reaction of fullerenes with soot; 3) positively identifying C 60 molecules in HRTEM by tethering them to carbon black; and 4) providing a cost estimation for industrial fullerenic soot production.Samples of condensable material from laminar low-pressure benzene/argon/oxygen diffusion flames were collected and analyzed by high-performance liquid chromatography (HPLC) and HRTEM. The highest concentration of fullerenes in a flame was always detected just above the height where the fuel is consumed. The percentage of fullerenes in condensable material increases with decreasing pressure and the fullerene content of flames with similar cold gas velocities shows a strong dependence on length. A shorter flame, resulting from higher dilution or lower pressure, favors the formation of fullerenes rather than soot, exhibited by the lower amount of soot and precursors in such flames. This indicates a stronger correlation of fullerene consumption to soot levels than of fullerene formation to precursor concentration. The maximum flame temperature seems to be of minor importance in formation. The overall highest amount of fullerenes was found for a surprisingly high dilution of fuel with argon. The HRTEM analysis 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 which it decreases, consistent with the HPLC analysis. The soot shows highly ordered regions that appear to have been cells of fullerenic nanostructure formation. The samples also included fullerenic nanostructures such as tubes and sp...

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“…The elimination of CO from oxidized PAH is thought to be a source of five-membered rings [18] in the structure of combustion-generated PAH, which are precursors to fullerenes in flames [19][20][21]. However, the highest concentration of fullerenes is in the region of the flame where the precursor concentration is decreasing due to oxidation.…”

Section: Fullerenesmentioning

confidence: 99%

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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Proposed fullerene precursor corannulene identified in flames both in the presence and absence of fullerene production

Cited by 76 publications

References 9 publications

IR, Raman, and UV/Vis Spectra of Corannulene for Use in Possible Interstellar Identification

IR, Raman, and UV/Vis Spectra of Corannulene for Use in Possible Interstellar Identification

Combustion synthesis of fullerenes and fullerenic nanostructures

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

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