Electrochemistry in Liquid SO 2 : IX . Oxidation of n‐Alkanes and Alkylammonium Ions at Pt Ultramicroelectrodes in Liquid

When CsAsF6 is used as the supporting electrolyte in liquid SO2, the anodic solvent limit is about +6V vs. SCE. This very positive potential range allows the electrochemical oxidation of straight-chain hydrocarbons (C~H2~+2 (n = 1-8)) and quaternary alkylammonium ions (R4N § (R = C2~H2~+ 1, n = 3-16)) to be studied in this solvent system by cyclic voltammetry at Pt ultramicroelectrodes (10 and 25 ~m). Single, totally irreversible, anodic voltammetric waves were observed. The peak potentials of these compounds became more negative with an increase in the length of the carbon chain. The peak poten- tials correlated with ionization potentials and the length of the carbon chain. Bulk electrolysis of n-hydrocarbons at low concentrations (1-5 mM) required 2 faradays per mole of hydrocarbon. However, when higher concentrations were em- ployed (>10 mM), the electrolytic current did not fall to background levels. Some delocalization of the C ~--~ bonds is pro- posed to account for the negative peak potential shift with increasing length of the hydrocarbon chain.