POLYMERIZATION OF ANILINE IN AQUEOUS SULFURIC-ACID STUDY BY ELECTROCHEMICAL THERMOSPRAY MASS-SPECTROMETRY

Electrochemical thermospray Mass Spectrometry (ETMS) has proved to be a suitable method for the investigation of electrode processes. The mechanisms for the anodic oxidation of N,N-dialkylanilines in neutral aqueous solution and of phenothiazine in non-aqueous methanol/ammonium acetate electrolyte solution were elucidated. These reactions showed formation of higher oligomers. First experiments were done on the electrochemical polymerization of aniline at a Pt-electrode in sulfuric acid. ETMS allows the detection of soluble products. Experiments with the rotating disc electrode indicate that the polymerization of aniline proceeds via soluble oligomers. Thermospray mass spectra are presented of the aniline/sulfuric acid electrolyte and of the electrochemically generated oligomers. Mass spectrometric cyclic voltamograms of aniline and the oxidation of isotope labeled aniline give information about the structure of dimers and trimers and a first insight in the mechanism of the aniline polymerization process.