Kinetics and Mechanism of Pyrolysis of Methyltrichlorosilane

Abstract

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, k1, 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, k1∞ = (9.6 ± 2.5) × 1019 exp (−(392 ± 18) kJ mol-1/RT) s-1. The rate constants for hydrogen abstraction, k2, and chlorine abstraction, k3, from MTS by methyl radicals were also calculated on the basis of experimental measurements. The Arrhenius expression for hydrogen abstraction was k2 = (5.1 ± 0.4) × 108 exp(−(61 ± 3) kJ mol-1/RT) L mol-1s-1 and for chlorine abstraction was k3 = (1.5 ± 0.5) × 109 exp(−(72 ± 6) kJ mol-1/RT) L mol-1s-1.