Polyynes: Synthesis with the Submerged Electric Arc - Polyynes: Synthesis, Properties, and Applications - page 173

appears that both PAHs and pyrocarbon are essentially formed from the
plasmalysis of the solvent. When halogenated solvents are employed in the
carbon arc in place of hydrocarbons or alcohols no polyynes and PAHs are
formed but only halogenated products. The formation rate of pyrocarbon
becomes extremely high in comparison to other solvents (see Table 8.2 ) .
Arcing titanium electrodes in alcohols in place of graphite electrodes
causes complete suppression in the formation of any polyyne. Only PAHs
produced from the pyrolysis of the solvents are obtained. This fact demon-
strates the key role played by the graphite electrodes in supplying the
elemental carbon for the formation of the polyynes.
ACKNOWLEDGMENTS
ASI, the Italian Space Agency, is gratefully acknowledged for financial sup-
port of this work under grant I/R/070/02. Discussions with W. Kraetschmer,
L. Kavan, and P. Milani are gratefully acknowledged.
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