Kinetics of the gas-phase reaction between iodine and trichlorosilane and the bond dissociation energy D(Cl3Si—H)

Abstract

The title reaction has been investigated in the temperature range 561–627 K. The principal products were trichlorosilyl iodide and hydrogen iodide, although small quantities of hydrogen were also formed. The rate law [graphic omitted] was obeyed over a wide range of iodine and trichlorosilane pressures. This expression is consistent with an iodine atom abstraction mechanism and for the step I˙+ Cl₃SiH [graphic omitted] Cl₃Si˙+ HI log(k₁/dm³ mol^–1 s^–1)=(10.92 ± 0.06)–(89.6 ± 0.7 kJ mol^–1)/RT ln 10 has been deduced. From this the bond dissociation energy D(Cl₃Si—H)=(382 ± 6) kJ mol^–1(91.3 kcal mol^–1) is obtained. The kinetic and thermochemical implications of this value are discussed.