Kinetics and Mechanism of Pyrolysis of Methyltrichlorosilane

The thermal decomposition of methyltrichlorosilane (MTS) was studied in a flow system in the temperature range of 825−977 K and pressure range of 10−120 Torr. Yields of products were measured by gas chromatography. The rate constant, k 1, for the initiation reaction was determined from the sum of the rates of the termination reactions. The Arrhenius expression for this reaction at the high-pressure limit was obtained from a nonlinear least-squares fit to the experimental data using the Troe factorization method, k 1 ∞ = (9.6 ± 2.5) × 10 19 exp (−(392 ± 18) kJ mol -1 / RT ) s -1 . The rate constants for hydrogen abstraction, k 2, and chlorine abstraction, k 3, from MTS by methyl radicals were also calculated on the basis of experimental measurements. The Arrhenius expression for hydrogen abstraction was k 2 = (5.1 ± 0.4) × 10 8 exp(−(61 ± 3) kJ mol -1 / RT ) L mol -1 s -1 and for chlorine abstraction was k 3 = (1.5 ± 0.5) × 10 9 exp(−(72 ± 6) kJ mol -1 / RT ) L mol -1 s -1 .