OH与TCE和PCE加成中间体消除反应的机理

用从头计算法在UHF/6-31G水平研究了羟基自由基与三氯乙烯和四氯乙烯形成的加成中间体的消除反应，通过振动分析确认了过渡态，计算了内禀反应坐标(IRC).研究表明，该反应消除一个氯化氢分子，形成具有平面构型的另一个中间体，反应活化势垒较低，分别为79.84kJ mol-1和62.68kJ mol-1,且二者反应在常温常压下是熵增、放热、吉布斯自由能ΔGΘ<Ο，具有较大自发趋势的过程。

Mechanisms for the Elimination Reaction of the Addition Radical Formed by Hydroxyl Radical with Trichloroethylene and Perchloroethylene

The ab initio method atUHF/6-31G level is used to probe the reaction meaction mechanism of the elimination reaction of the addition radical formed by hydroxyl radical with Trichloroethylene and Perchloroethylene.The optimized transition state (TS) is tested by vibrational analysis,and the intrinsic reaction coordinate (IRC) calculations are performed.The reaction can proceed with eliminating a hydrogen chloride molecule to form an intermediate radical whose configuration is planar.The activation energy barrier is low,it is 79.84kJ mol-1 and 62.68kJ mol-1 respectively,both the elimination reactions under normal temperature and pressure are entropy increase,exothermal and Gibbs free energy ΔGΘ<Ο,that is,strongly spontaneous processes.