The thermolysis of ethyltrichlorosilane and ethyltrimethylsilane

The thermal decompositions of ethyltrichloro-and ethyltrimethyl-silane have been studied in the gas phase at 823K. The main primary process in each case is the dehydrosilylation reaction X₃SiCH₂CH₃ → X₃SiH+CH₂ = CH₂ (X = Cl or Me), though several additional products are formed, mainly in secondary reactions. It is concluded that the dehydrodesilylations involve a radical chain sequence, and that the formation of vinyl chloride by dehydrosilylation during the thermolysis of (2-chloroethyl) trichlorosilane probably also follows a radical pathway rather than the four-centre molecular process previously suggested. The following reactions at ca. 823K have also been briefly examined: (i) the thermal decomposition of trichlorosilane; (ii), the interaction of ethylene and tri-chlorosilane; (iii) the thermal decomposition of vinyltrichlorosilane.