Howard J B, McKinnon J T, Makarovsky Y, Lafleur A L, Johnson M E
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge 02139-4307.
Nature. 1991 Jul 11;352(6331):139-41. doi: 10.1038/352139a0.
The fullerenes C60 and C70 were first identified in carbon vapour produced by laser irradiation of graphite, and have recently been produced in macroscopic quantities by vaporization of graphite with resistive heating. It has also been suggested that fullerenes might be formed in sooting flames, and indeed all-carbon ions with mass/charge ratios suggestive of fullerenes have been detected in flames. These species were assumed to have the cage structures of fullerenes, but the mass spectroscopic evidence could not establish this conclusively. We have now collected samples of condensible compounds and soot from hydrocarbon combustion under a range of conditions, and analysed these using conventional techniques in an effort to detect fullerenes. Spectroscopic studies reveal the presence of C60 and C70 in yields and ratios that depend on temperature, pressure, carbon/oxygen ratio and residence time in the flame. Control of these conditions allows optimal yields of 3 g of fullerenes per kilogram of fuel carbon burned, and variation of the C70/C60 ratio over the range 0.26-5.7.
富勒烯C60和C70最初是在激光照射石墨产生的碳蒸气中被发现的，最近通过电阻加热使石墨汽化已能大量生产。也有人提出富勒烯可能在煤烟火焰中形成，事实上在火焰中已检测到质荷比表明为富勒烯的全碳离子。这些物质被认为具有富勒烯的笼状结构，但质谱证据无法确凿地证实这一点。我们现在已经在一系列条件下收集了烃类燃烧产生的可冷凝化合物和煤烟样本，并使用传统技术对其进行分析，以努力检测富勒烯。光谱研究表明，C60和C70的存在量和比例取决于温度、压力、碳/氧比以及在火焰中的停留时间。控制这些条件可使每燃烧一千克燃料碳的富勒烯最佳产量达到3克，并使C70/C60比例在0.26至5.7的范围内变化。
