Mechanism and kinetics of the shock‐tube decomposition of vinylsilane

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Abstract
The shock‐induced thermal decompositions of vinylsilane and vinylsilane‐d3 (0.2% on argon) have been studied in the temperature range of 1085–1275 K, and at total pressures of about 3100 torr. In systems without silylene traps, some induced decomposition occurs which is attributed to the silylene chain sequence VSiH → C2H2 + SiH2, S̈iH2 + VSiH3 ⇄ VSiH2SiH3 → VSiH2S̈iH + H2, VSiH2S̈iH → VSiH + S̈iH2. In the presence of silylene traps (butadiene and acetylene), the overall decomposition kinetics are log k(VSiH3, s−1) = 14.95 − 63,268 cal/2.303RT and log k(VSiD3, s−1) = 15.14 − 64,815 cal/2.303RT. Three primary processes contribute to the decomposition: 1,1‐H2 elimination, 1,2‐H2 elimination, and ethylene elimination. Two mechanisms are proposed, one for exclusive primary process formation of C2H4, and the other for both primary and secondary formation routes. Modeling studies are reported which show that both mechanisms can be made compatible with the rate and product yield data within experimental errors.