采用多种密度泛函理论方法(如 CAM-B3LYP, M062x 和 wB97x 方法),并辅以极化连续介质模型对叔丁氧基自由基( t BuO·)与一系列胺类、烷烃、醇类和醚类反应物之间氢迁移反应的反应机理进行研究。计算结果表明,这类氢迁移反应主要受熵的控制。通过对液相平动熵和气相平动熵得到的活化自由能数据进行对比,可以看出,使用气相平动熵得出的活化自由能明显偏高于实验测量值,而以液相平动熵计算的反应活化自由能垒与实际结果相近,3种方法对胺类和烷烃类反应物体系得出的结果更可靠,对醇类和醚类反应物体系自由能垒则略低。%The reaction mechanisms of hydrogen abstractions from carbon by the t-butoxyl radical were investi-gated with several density functional theory(DFT) methods, such as CAM-B3LYP, M062x and wB97x. The results show that most of these reactions are dominated more by entropic than by enthalpic factor. The activation free energy barriers were calculated with both gas-phase translational entropy and solution transla-tional entropy, in which those from ideal gas-phase translational entropy(output of Gaussian job) were much higher than the experimental estimations. It has been verified that free-energy barriers of amines and hydrocar-bons reactions generated from solution translational entropies are close to the experimental measurements, but all these methods predict a little low free-energy barriers for alcohols and ethers reactions.
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