Electrochemical oxidation of quaternary ammonium electrolytes : Unexpected side reactions in organic electrochemistry

摘要: Quaternary ammonium salts are among the most widely used electrolytes in organic electrochemistry, but there is little known about their unwanted side oxidation reactions. We have, therefore, studied constant potential products of quaternary using mass spectrometry, and proposed reaction mechanisms were verified by stable isotope labeling studies. Oxidation tetrabutylammonium at +2.5 V vs Ag showed m/z 256, 258, 299 which shown corresponding to alcohol, ketone, acetonitrile-derived amide products, respectively. propose a mechanism based on anodic chain, generate carbocation, followed nucleophilic attack water or acetonitrile. Incorporation molecule and/or an acetonitrile structure was analysis isotopically labeled products. can be avoided use ions with shorter alkyl chains, where electrostatic repulsion presumably prohibits carbocation generation. (C) 2012 Elsevier B.V. All rights reserved.