Raman spectroscopy was employed to study the polymerization of pyrrole
over a selection of copper-exchanged ZSM-5 zeolites. No polymerizatio
n occurred on catalysts of low copper content, which suggested that a
critical concentration of copper(II) cations was required for reaction
. On ZSM-5 materials with low Si/Al ratios, bands were detected which
were characteristic of partially oxidized polypyrrole and monomeric py
rrole. The polymer was degraded in the presence of residual oxygen. It
was shown that the polymer incorporated both aromatic- and quinoidal-
type structures. Further, resonance Raman spectroscopy suggested that
the charge carrier present in the oxidized polymer was associated with
the quinoid arrangement.