Pathways of polycyclic hydrocarbon formation during plasma arcing of carbonaceous materials

A number of plasma arcing experiments have been carried out using naphthalene as fill in hollow graphite anodes in order to simulate the way fullerenes might be formed from polycyclic hydrocarbons in coal. The results show that naphthalene in the plasma are fringe increases the C-70 to C-60 fullerene ratio in the product soot. The most probable explanation is that naphthalene is more readily incorporated into the C-70 fullerene structure because two aromatic rings together can be accommodated. C-60 fullerene may incorporate naphthalene, but only after a six to five membered ring rearrangement. It is generally believed that fullerenes are constructed from single C-1 or double C-2 carbon units when graphite is used as the anode. The results offer strong evidence that fullerenes can be produced via processes involving larger primary fragments when naphthalene is present in the anode. (C) 1997 Published by Elsevier Science Ltd.