Mechanism and kinetics of the silane decomposition in the presence of acetylene and in the presence of olefins

Kinetic data and product studies are reported for the silane pyrolysis in the presence of olefins and acetylene. The kinetics of silane loss in the presence of acetylene was found to be identical to the initial gas phase silane decomposition step (SiH4 + M → SiH2 + H2 + M) when corrected for pressure fall‐off effects. This result and the absence of methane or ethane from the pyrolysis of SiH4 in the presence of 1‐butene or 1‐pentene demonstrate that silyl radicals and H atoms are not involved in silane‐olefin or silane‐acetylene reactions. Qualitative aspects and kinetic data from the SiH4 pyrolysis in the presence of propylene are in accord with propylsilane formation via propylsilylene formed by silylene addition to propylene.