Production of C{sub 60} and C{sub 70} fullerenes in benzene-oxygen flames
- Massachusetts Institute of Technology, Cambridge, MA (United States); and others
Fullernes C{sub 60} and C{sub 70} were produced in varying amounts in premixed laminar benzene/oxygen/argon flames operated under ranges of conditions including pressures of 12-100 Torr and C/O ratios from 0.717 to 1.072, the critical value for soot formation being 0.760. The fullernes were identified in toluene extracts of condensed flame material including soot, using high-performance liquid chromatography (HPLC) with diode-array spectrophotometric detection, mass spectrometry, and infrared spectrophotometry. The yields of C{sub 60} and C{sub 70} and the C{sub 70}/C{sub 60} ratio depend on temperature, pressure, carbon/oxygen ratio, and residence time in the flame. In the sooting flames, C{sub 60} and C{sub 70} first appear well after the onset of soot formation. The mass of C{sub 60} + C{sub 70} produced is in the range 0.0026-902% of the soot, compared to 1-14% of the fuel carbon was found in a nonsooting flame. The largest rate of production of C{sub 60} + C{sub 70} was observed in a sooting flame at a pressure of 100 Torr. The C{sub 70}/C{sub 60} molar ratio varied over the range 0.26-5.7, compared to 0.02-0.18 for the graphite vaporization method, and can be controlled by selection of flame conditions. Depending on flame conditions, the C{sub 60} + C{sub 70} fullernes were produced with varying amounts of polycyclic aromatic hydrocarbons (PAH). The mass ratio of PAH to C{sub 60} + C{sub 70} varies roughly from 0.01 to 100 over the range of conditions studied. Also, the C{sub 60} + C{sub 70} fullerenes are accompanied by metastable C{sub 60} and C{sub 70} isomers as well as C{sub 60}O, C{sub 70}O, C{sub 76}, C{sub 84}, C{sub 90}, and C{sub 94}, the identification of which by liquid chromatography/mass spectrometry is described elsewhere. 49 refs., 5 figs., 2 tabs.
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- FG02-84ER13282
- OSTI ID:
- 468073
- Journal Information:
- Journal of Physical Chemistry, Vol. 96, Issue 16; Other Information: PBD: 6 Aug 1992
- Country of Publication:
- United States
- Language:
- English
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