【摘要】 在ρ-硝基氯苯(1)与α-氰基乙酸乙酯-α-碳负离子(2)的反应过程中,测得了反应中间体ρ-硝基氯苯负离子自由基(3)的ESR谱.用ESR场/频联锁技术测定了(3)的ESR吸收强度-时间曲线,当[1]<<[2]时,其结果与连续一级反应动力学相吻合.测得了从2向1的电子转移和3的分解反应速率常数和活化参数.反应产物为α-氰基α-(ρ-硝基苯基)乙酸乙酯和微量的硝基苯.为该反应提出了非链式的电子转移-负离子自由基分解-自由基偶合机理.更多还原

【Abstract】 The ESR spectrum of p-nitrochlorobenzene anion radical (3) resulting from single electron transfer reaction of p-nitrochlorobenzene (1) with ethyl α-cyanoacetate-α-carbanion (2) in DMSO has been recorded at various temperatures by means of ESR F/F lock technique. It was found that when [1]<<[2], the reaction gave the kinetic expression for successive first-order reaction. The rate constants and the activation parameters for the SET reaction from 2 to 1 and the decomposition of 3 were determined. The products were found to consist of chiefly ethyl α-cyano-α-(p-nitrophenyl) acetate and minute amount of nibrobenzene. A non-chain radical mechanism of aromatic nucleophilic substitution is proposed.更多还原