FABRICATION OF FULLERENES IN BENZENE OXYGEN/ARGON AND BENZENE/ACETYLENE/OXYGEN/ARGON FLAMES/

The synthesis of fullerenes in benzene/oxygen flames has been describe d in the literature. A combustion chamber equipped with a burner of an effective diameter of 100 mm has been constructed in order to burn fl at premixed hydrocarbon/oxygen flames at low pressure. In this work 21 benzene/oxygen/argon and 3 benzene/acetylene/oxygen/argon names have been studied varying the atomic C/O ratio, the percentage of argon, th e velocity of the initial fresh gas mixture, the pressure and the acet ylene fraction of the combustible. The fullerene content of the soot h as been analyzed quantitatively by means of HPLC chromatography. Mass spectrometric measurements showed the possible presence of heavier ful lerenes up to more than C-150- (C-60 + C-70) formation rates up to 588 mg h(-1) have been observed while the maximum (C-60 + C-70) percentag e in the soot reached 6.1%. The C-60/C-70 ratio varied as a function o f the atomic C/O ratio. The predominance of fullerene formation by coa gulation compared to direct formation by multiple addition of acetylen e has been suggested.