FULLERENE FORMATION IN ACETYLENE OXYGEN/ARGON/CHLORINE FLAMES/

The impact of Cl-2 addition on the fullerene formation in acetylene/ox ygen/argon flat flames burning at low pressure was investigated. The q uantities of C-60 and C-70 in the soot were determined by HPLC after e xtraction with toluene. Negative ion mass spectra were measured using chemical ionization by means of a CH4/N2O mixture. The chlorine contai ning species were identified by means of a precursor ion mass spectrum . The addition of 25% of Cl-2 led to a dramatic increase of fullerene formation; soot containing 7.7% of (C-60+C-70) was deposited in the co mbustion chamber. The mass spectra showed signals at the masses of C10 H2, C11H8 and C12H10 for soot formed in flames with and without chlori ne addition while peaks corresponding to the polycyclic aromatic hydro carbons (PAH) C18H10, C22H12 and C24H12 could be observed only without chlorine addition. A positive role of thermally and photochemically u nstable chlorinated intermediate species is suggested for the increase of fullerene formation. Copyright (C) 1996 Elsevier Science Ltd