Electrochemistry in Near-Critical and Supercritical Fluids. 5. The Dimerization of Quinoline and Acridine Radical Anions and Dianions in Ammonia from -70C to 150C

摘要

An experimental apparatus capable of supporting electrochemical measurements in ammonia at high temperatures and pressures is described. The dimerization reactions of the radical anions of quinoline and acridine were studied over a 220 C temperature range in ammonia. The cyclic voltammetric and chronoamperometric experiments were analyzed by the theory for reversible dimerizations. At low temperature the dimerization was totally irreversible, but at elevated temperatures the rate of the back reaction was significant and the dimerization reaction was facile. The rates of the dimerization reactions were extrapolated to very high temperature, and were found to be in qualitative agreement with cyclic voltammetric results in supercritical ammonia. The activation energies for the dimerization reactions are reported. The diffusion coefficients of quinoline and acridine from -70 C to 150 C are reported.