Thermal decomposition of tetramethylsilane (TMS) was studied over the temperature range of 298-1450 K by combining flash pyrolysis vacuum ultraviolet photoionization time-of-flight mass spectrometry (VUV-PI-TOFMS) and density functional theory (DFT). The initial step of TMS pyrolysis produced methyl radical (Me) and Me3Si. Me3Si underwent subsequent loss of a hydrogen atom to form Me2Si=CH2 and loss of a methyl radical to form Me2Si:. Isomerizations via 1,2-shift and H2 eliminations were major secondary decomposition reactions of Me2Si=CH2 and Me2Si:. Among the various isomers, silylene species containing Si-H bond, such as :Si(H)CH2CH2CH3, :Si(H)CH2CH=CH2, :Si(H)CH2CH3, and :Si(H)CH=CH2, played an important role in H2 elimination reactions. On the other hand, silene species were insignificant in H2 eliminations. Unlike the silylene species, H2 elimination of :Si=CH2 was energetically unfavorable.

Mechanism of thermal decomposition of tetramethylsilane: A flash pyrolysis vacuum ultraviolet photoionization time-of-flight mass spectrometry and density functional theory study

2019 Spring National Meeting

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