Thermal Decomposition Mechanism of Tetraethylsilane by Flash Pyrolysis Vacuum Ultraviolet Photoionization Mass Spectrometry and DFT Calculations: The Competition between β-Hydride Elimination and Bond Homolysis
Thermal Decomposition Mechanism of Tetraethylsilane by Flash Pyrolysis Vacuum Ultraviolet Photoionization Mass Spectrometry and DFT Calculations: The Competition between β-Hydride Elimination and Bond Homolysis
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四乙基硅烷的快速热解真空紫外光电离质谱和 DFT 计算的热分解机理：β-氢化物消除与键均质分解之间的竞争
DOI：
10.1021/acs.jpca.2c09081
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Zhang, Jingsong
中科院分区：
文献类型：
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作者：
Shao, Kuanliang;Liu, Xinghua;Zhang, Jingsong
用闪光热解真空紫外光电离质谱仪研究了四乙基硅烷在1330K以下的热分解。用密度泛函理论和过渡态理论计算证实了实验结果。实验和理论证据都表明，四乙基硅烷的热解是由主要反应产物三乙基硅基(SiEt3)和乙基自由基的Si-C键断裂引发的。在三乙基硅自由基的二次反应中，在较低的温度下，β-氢化物消除途径(生成HSiEt2)比其竞争的反应通道Si-C键断裂(生成：SiEt2)更有利；随着温度的进一步升高，Si-C键裂解反应变得更加明显。确定了其他重要的二次反应产物，如EtHSi═CH2(m/z=72)、H_2SiEt(m/z=59)和SiH_3(m/z=31)，并提出了它们的形成机理。
Thermal decomposition of tetraethylsilane was investigated at temperatures up to 1330 K using flash pyrolysis vacuum ultraviolet photoionization mass spectrometry. Density functional theory and transition state theory calculations were performed to corroborate the experimental observations. Both experimental and theoretical evidence showed that the pyrolysis of tetraethylsilane was initiated by Si–C bond fission to the primary reaction products, triethylsilyl (SiEt3) and ethyl radicals. In the secondary reactions of the triethylsilyl radical, at lower temperatures, the β-hydride elimination pathway (producing HSiEt2) was found to be more favored than its competing reaction channel, Si–C bond fission (producing :SiEt2); as the temperature further increased, the Si–C bond fission reaction became significant. Other important secondary reaction products, such as EtHSi═CH2(m/z= 72), H2SiEt (m/z= 59), and SiH3(m/z= 31) were identified, and their formation mechanisms were also proposed.