Fu Yan-Hua, Shen Guang-Bin, Wang Kai, Zhu Xiao-Qing
College of Chemistry and Environmental Engineering, Anyang Institute of Technology, Anyang, Henan 455000, China.
School of Medical Engineering, Jining Medical University, Jining, Shandong 272000, P. R. China.
ACS Omega. 2022 Jul 12;7(29):25555-25564. doi: 10.1021/acsomega.2c02700. eCollection 2022 Jul 26.
The H-abstraction activity of a free radical is a research hotspot and has been extensively studied. In this article, the second-order rate constants of 21 HAT reactions in acetonitrile at 298 K were chosen from several published literature. A kinetic study on the H-abstraction reaction from TEMPOH by a DPPH radical was carried out. This reaction was researched as an insertion point. By combining this reaction with the 21 HAT reactions in this paper, the thermokinetic parameters of 28 free radicals X and their corresponding antioxidants XH were obtained by the cross-HAT reaction method. The scales of the H-abstraction activities of these 28 oxygen and nitrogen free radicals were determined by using the thermokinetic parameters Δ (X). Applications of the thermokinetic parameter Δ (X) in assessing the actual H-abstraction activity of a free radical quantitatively and selecting a suitable free radical in scientific research and chemical production were discussed. Predictions of the rate constants by using thermokinetic parameters of reactants were researched, and the reliabilities of the predicted activation free energies of XH/Y reactions were also examined.
自由基的氢原子提取活性是一个研究热点，且已得到广泛研究。在本文中，从多篇已发表文献中选取了21个在298 K乙腈中的氢原子转移（HAT）反应的二级速率常数。对DPPH自由基从TEMPOH提取氢原子的反应进行了动力学研究。该反应被作为一个切入点进行研究。通过将此反应与本文中的21个HAT反应相结合，采用交叉氢原子转移（cross-HAT）反应方法获得了28种自由基X及其相应抗氧化剂XH的热动力学参数。利用热动力学参数Δ( X)确定了这28种氧自由基和氮自由基的氢原子提取活性尺度。讨论了热动力学参数Δ( X)在定量评估自由基实际氢原子提取活性以及在科研和化学生产中选择合适自由基方面的应用。研究了利用反应物的热动力学参数预测速率常数，并检验了预测的XH/Y反应活化自由能的可靠性。
