Electrochemical thermospray mass spectroscopy - anodic oxidation of N, N-dialkylanilines

The coupling of an electrochem. cell online with a thermospray mass spectrometer can be used for the identification of reaction products. The objective of this study was to demonstrate the performance of electrochem. thermospray mass spectrometry (ETMS). The anodic oxidn. of N,N-dialkylanilines in 0.1M NH4OAc was studied. Structural information on the products were obtained by measurements in D2O-based electrolyte soln. The 1st step was the oxidn. of dialkylaniline to radical cations. Recombination of the radical cations formed benzidine as the chief product. In the main side reaction the radical cations were deprotonated at the C-H acid .alpha.-carbon atom to radicals. A part of these radicals was oxidized at the electrode to immonium ions. By follow up reactions, such as hydrolysis, dealkylation, oxidn. and recombination with monomeric radical cations, dimers were formed. Repeating the side reaction, these dimers reacted to give trimers and higher oligomers. A scheme of the different reaction pathways is presented.