The ESR spectrum of p-nitrochlorobenzene anion radical (I) resulting from single electron transfer (SET) reaction of p-nitrochlorobenzene (II) with Na+-CH(CN)CO2Et (III) in DMSO has been recorded at various temps. by means of ESR F/F lock technique. It was found that when II ?III, the reaction gave the kinetic expression for successive first-order reaction. The rate constants and the activation parameters for the SET reaction from III to II and the decomposition of I were determine The products were found to consist of chiefly Et a-cyano-a-(p-nitrophenyl)acetate and minute amount of nitrobenzene. A non-chain radical mechanism of aromatic nucleophilic substitution is proposed.

Key words: REACTION MECHANISM, CYANO GROUP, FREE RADICAL, ELECTRON SPIN RESONANCE, ELECTRON TRANSFER REACTION, KINETIC STUDY, NITROCHLOROBENZENE, CARBON ION, ETHYL ACETATE P