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Atomic insights into the thermal runaway process of hydrogen peroxide and 1,3,5-trimethybenzene mixture: Combining ReaxFF MD and DFT methods
Process Safety and Environmental Protection ( IF 6.9 ) Pub Date : 2021-01-02 , DOI: 10.1016/j.psep.2020.12.036
Yanan Qian , Wei Xu , Jin-Hui Zhan , Xuewu Jia , Fan Zhang

The explosive hazard of hydrogen peroxide (H2O2) and organics mixtures had drawn much attention, but the mechanism is still unclear. In this work, the atomic insights into the thermal runaway process of H2O2 and 1,3,5-trimethylbenzene (TMB) mixture was conducted using a new approach of combining reactive molecular dynamics (ReaxFF MD) and density function theory (DFT). The detailed reaction pathways were obtained through ReaxFF MD. The kinetic and thermal properties of main reaction steps were examined by DFT. This work divided the thermal runaway process into two stages. In Stage I, H2O2 molecules were decomposed first to generate ·OOH and ·OH free radicals. The ·OH radicals induced the initial oxidation of TMB molecular through H-abstraction and ·OH-combine reaction steps with the highest thermal energy of 921.76 kJ/mol released, evoking the opening and cracking of benzene ring. In stage II, once the generated small molecules were further oxidized, the reactions showed a runaway for the massive thermal energy released, which explains the mechanism of larger potential risk of H2O2-organics mixture. Notably, ·OH is the most crucial free radical carrier for the whole reaction process, the explosion hazard will be inhibited or weakened if the concentration of ·OH radical is controlled. It is expected that this work will help researchers and industrial practitioners to better understand the intrinsic thermal hazard of H2O2-organics, and provide valuable guidance for the further development of efficient explosion suppression methods.



中文翻译:

关于过氧化氢和1,3,5-三甲基苯混合物的热失控过程的原子见解:结合ReaxFF MD和DFT方法

过氧化氢(H 2 O 2)和有机物混合物的爆炸危险引起了广泛关注,但其机理尚不清楚。在这项工作中,使用结合了反应性分子动力学(ReaxFF MD)和密度函数理论(DFT)的新方法对H 2 O 2和1,3,5-三甲基苯(TMB)混合物的热失控过程进行了原子洞察。)。详细的反应途径是通过ReaxFF MD获得的。通过DFT检查主要反应步骤的动力学和热学性质。这项工作将热失控过程分为两个阶段。在第一阶段,H 2 O 2分子首先分解产生·OOH和·OH自由基。·OH自由基通过H-吸收和·OH-结合反应步骤诱导TMB分子的初始氧化,释放出的最高热能为921.76 kJ / mol,引起苯环的开裂和裂化。在阶段II中,一旦生成的小分子被进一步氧化,反应就显示出大量热能释放失控,这解释了H 2 O 2潜在风险更大的机理。-有机混合物。值得注意的是,·OH是整个反应过程中最关键的自由基载体,如果控制·OH自由基的浓度,爆炸危险将得到抑制或减弱。预期这项工作将有助于研究人员和工业从业人员更好地了解H 2 O 2有机物的固有热危害,并为进一步开发有效的爆炸抑制方法提供有价值的指导。

更新日期:2021-01-02
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