Preparation of Polypyrrole from Pyrrole by Using the Catalytic System of VO(acac)2–AlCl3–O2

Polypyrrole was prepared by the oxidation of pyrrole with molecular oxygen in the presence of bis(acetylacetonato)(oxo)vanadium(IV) (VO(acac)2) and aluminum chloride (AlCl3) as a catalyst. The polymerization of pyrrole at 20 °C at a mole ratio of VO(acac)2/AlCl3 = 1/1 in acetonitrile under 1 atm of oxygen gave polypyrrole, 10−2 S cm−1 in electrocondutivity in 260% yield on the basis of the catalyst charged. The addition of pyridine to the system improved the electroconductivity of the polypyrrole produced. The reaction mechanism is discussed based on the UV-vis spectra of the reaction mixtures, the ESR spectra of the catalytic system, and the oxygen consumption during polymerization.