ELECTROCHEMICAL CONVERSION OF ALPHA-NITROBENZYLIC COMPOUNDS INTO THE CORRESPONDING OXIMES .2. MACROSCALE ELECTROLYSES

Electroreduction of alpha-nitrobenzylic compounds, performed in aqueous acetic buffer (65%) and ethanol (35%) leads to a mixture of oxime and hydroxylamine; the latter can be oxidized into oxime, via the corresponding nitroso. Differents strategies have been developed in order to improve the conversion yield into oxime: controlled potential reduction in a batch cell at a mercury pool cathode, followed either by chemical iodine oxidation or by controlled potential oxidation; galvanostatic electrolyses carried out in a flow cell fitted either with two consecutive porous electrodes of opposite polarities or with only a porous cathode, the flowing out solution being oxidized with iodine. The last method gives the best results and conversion yields of 90% are reached.