Selective oxidation of p-xylene by emulsion electrolysis yields p-tolualdehyde. The reaction was carried out with platinum electrodes at 35-40 degrees C in an undivided cell with an emulsion consists of chloroform containing substrate and an aqueous solution of 2% sodium nitrate as a mediator with a catalytic amount of H2SO4. The electrochemical oxidation was optimized with various experimental parameters to result in high yield of p-tolualdehyde (84%). Crown Copyright (C) 2013 Published by Elsevier Ltd. All rights reserved.