Reactions of trifluoromethyl radicals. II. Hydrogen abstraction from monochlorosilane

Abstract

Hydrogen atom abstraction from SiH₃Cl by CF₃ radicals                   CF₃ + SiH₃Cl → CF₃H+SiH₂Cl                    (1) has been studied in the temperature range 69-168°. The rate constant, based on Ayscough's value of 10^13.36 cm³ mol^-1 s^-1 for the recombination of CF₃ radicals, is given by (k₁ in cm³ mol^-1 s^-1, E in kJ mol^-1):                    logk₁ = (12.38±0.06)-(25.72±0.41)/2.303RT At 400 K, the rate constant for CF₃ + SiH₃Cl is greater than the average value reported for CF₃+SiHCl₃ by a factor of 3.6. This is due to a difference in A factors since the activation energies are equal within experimental error.