FULLERENE SYNTHESIS BY LASER PYROLYSIS OF HYDROCARBONS

A novel route for the synthesis of carbon soots containing fullerene; has been developed i.e. the pyrolysis of hydrocarbons in gas, vapour o r aerosol phase, which are heated and decomposed through the absorptio n of IR photons emitted by a high power CW CO2 laser. Hydrocarbons suc h as benzene (+ cyclopentadiene), acetylene or ethylene have been test ed, pure or mixed with an oxidizer agent (nitrous oxide or oxygen) and /or a sensitizer (sulfur hexafluoride). The fullerenes were identified in the soots obtained by using as precursor the benzene/oxygen or ace tylene/oxygen mixture. When these compounds are produced in significan t amounts they can be detected directly in the as-formed soots by Four ier Transform Infrared Spectroscopy (FTIR). For small quantities, a So xhlet extraction procedure is necessary and th:extracts are characteri zed by FTIR and by other methods which are more sensitive, like mass s pectrometry or High Performance Liquid Chromatography (HPLC) coupled w ith ultraviolet-visible spectroscopy. The influence of the operating c onditions is discussed. (C) 1997 Elsevier Science Ltd.